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Thin branch of the science has made so much progress of late years, that a very wide and inviting field has been laid open. Several hundred new substances have either been dis- covered, or their characters have been determined with such preci- sion, and their composition investigated with such accuracy, as to give a pretty accurate idea of their constitution, and of their con- nexion with each other. These ultimate analyses, with a very few exceptions, have been all made upon the continent, and chiefly in Germany and France. British chemists have scarcely entered up- on the investigations. Dr Prout, indeed, 'v 1827, published an analysis of sugar, starch, lignin, and some of tlu> vegetable acids. His results were accurate, but his apparatus was of too complex a nature to warrant trust-worthy results in the hands of ordinary ex- perimenters. Within these very few years, Mr Kane of Dublin, and Dr Gregory, who liad been trained to vegetable analysis in Liobig's laboratory in Giessen, have liegun the investigation of vegetable bodies. Already various important facts have been ascertained by them; and, if they continue their investigations, there can be no doubt, from their well known sagacity and dex- terity, that many important discoveries in this interesting branch of chemistry will result from them. The present volume, by exhibiting a pretty complete view of the present state of vegetable chemistry j and, by presenting together the most important facts that have been ascertained, will, I trust, be of some use to those British chemists, who may wish to enter upon this very interesting field of investigation. I had intended at first to have given a minute detail of the method employed for obtaining an accurate analysis of a vegetable substance. But, after considering the subject maturely, I was in- duced by two circumstances to delay these details till the publica- VI PHEFACE. tion of my next volume on Animal Substances, which will complete my plan. The first of these is the great and unexpected size to which this volume has swelled. This has rendered it necessary to leave out every thing that did not constitute an essential part of the subject. The second circumstance, which induced me to delay the descrip- tion of the mode of the analysis to the next volume, is the very minute details of that method which have been given by Liebig and Dumas, the two chemists to whom we are indebted for the greatest number, and the most accurate vegetable analyses which we possess. Liebig contrived the most important part of the apparatus ; and in his Handworterhuch {dictionary) der reinen und angewandten Chemie, under the word Analyse, organische, he has given such minute de- tails of the whole steps of the process, accompanied by accurate figures of the apparatus, that every chemist, who peruses it witl» care, can feel no difficulty in analyzing any vegetable substance whatever. Professor Liebig has published this article as a separate pamphlet. Were any person to favour us with an English transla- tion of it, he would contribute essentially to promote the prosecu- tion of vegetable chemistry in Great Britain, and would be confer- ring an important favour on the British chemical public. Dumas, in the Introduction to the 5th volume of his Traite de Chimie ap- pliquee aux Arts, has also given a minute detail of the methods of analyzing vegetable bodies, and pointed out various methods of checking the errors to which the method is liable, and of deducing the atomic weight from methods independent of the elementary analysis. His observations are highly worthy of an attentive per- usal, and cannot fail to communicate much useful information. Professor Mitscherlich of Berlin, has made some attempts to im- prove the apparatus of Liebig ; though I doubt whether the addi- tional accuracy is not more than compensated by the complicated nature of his improvements. To him, as well as to H. Rose, Pe- louse, and some other young French chemists, we are indebted for a great number of accurate vegetable analyses. ^^ C CONTENTS. Lntroduction, DIVISION I. OF VEGETABLE PRINCIPLES, 14 Class I. Vegetable Acids, Chap. I. Volatile acids. Sect. 1. Oxalic acid, 2. Croconic acid, 3. Formic acid, 4. Mellitic acid, 5. Succinic acid, 6. Acet'"e acid, 7. Lactic acid, 8. Suberic acid, 9. Naphthalic acid, 10. Sebacic acid, 1 1 . Camphoric acid, )2. Valerianic acid, 13. Benzoic acid, « 14. Cinnamonic acid, 15. Hippuric acid, 16. Esculic acid, ("hap. II. Of fixed acids. Sect. 1. Malic acid, 2. Equisetic or maleic acid, 3. Fumaric, lichenic, or paramaleic 4. Citric acid, 5. Pyrocitric acid, 6. Citricic acid, [Appendix] 7. Paratartaric acid, [Appendix] 8. Pyrotartaric acid, 9. Pyruvic acid, 10. Racemic acid, 11. Oxalhydric acid, 12. Mucic acid, 13. Paramucic acid, 14. Pyromucic acid, 15. Meconic acid, 16. Pyromeconic acid, 17. Metameconic acid, 18. Gallic acid, 19. Pyrogallic acid. acid 14 15 15 17 17 19 20 21 22 26 27 31 33 35 42 43 46 50 52 53 54 57 58 62 1039 1042 63 65 G6 75 77 78 80 80 82 83 84 86 via CONTENTS. Sect. 20. Metagallic acid, .... PAOI! 88 21. Kinic acid, ..... 89 22. Pyrokinic acid, .... 93 23. EUagic acid, ..... 93 24. Cahincic acid, j 94 25. Bicoloric acid, .... 96 26. CaflPeic acid, ..... 98 27. Picrotoxic acid, .... 100 28. Mechloic acid, .... 103 29. Amygdalic acid, .... 104 30. Tannic acid, ..... 107 31. Catechuic acid, .... 112 32. Japonic acid, 116 33. Rubinic acid, ..... 118 34. Ulmic acid, 119 Chap. III. Of oily acids, 120 Sect. 1. Margaric acid, .... 120 2. Stearic acid, ..... 122 3. Metamargaric acid, .... 122 4. Meta-oleic acid, .... 124 5. Hydromargaric acid, 124 6. Hydro-oleic acid, .... 125 7. Anchusic acid, .... 127 8. Roccellic acid, . . . . , 128 9. Chlorophenisic and chlorophenesic acids, . 129 10. Santonin, 133 11. Smilacin, ...... 137 12. CEnanthic acid, .... 138 Chap. IV. Of acids containing azote. 140 Sect. 1. Azulmic acid, ..... 140 2. Indigotic acid, 141 3. Carbazotic acid, .... 142 4. Aspartic acid, .... 143 5. Cholesteric acid, .... 144 6. Ambreic acid, .... 145 Chap. V. Acids imperfectly examined, 146 Sect. 1. Pectic acid, ...... 146 2. Crenic acid, 147 3. Apocrenic acid, .... 153 4. Puteanic acid, .... 156 5. Palmic acid, ..... 156 6. Gummic acid, 157 7. Igasuric or strychnic acid, 157 8. Vulpinic acid, .... 158 9. Lactucic acid, ...... 159 10. Verdous and verdic acids 159 ll.Ilhein, 160 12. Polygalic acid, .... 162 1 3. Comic acid, 164 14. Gentisic acid, 165 15. Ampelic acid, 167 Chap VI. Of compomid acids, .... 168 1 i CONTENTS. IX /■ I'AOB PAOB ¥ 88 Sect. 1. Althionic acid, 169 89 2. Oxalovinic acid, .... 172 93 3. Tartrovi) '>', acid, .... 173 93 4. Racer. K .c acid, .... 177 94 5. Sidphoi ■ i iylic acid. 179 96 6. Tartroiiietiiylic acid. 180 98 7. Racemomethylic acid. 183 100 ,_. 8. Phosphovinic acid, .... 185 103 1 9. Arseniovinic acid, .... 188 104 i 10. Camphovinic acid, .... 189 107 '■' 11. Ethionic acid, .... 190 112 12. Sulphonapthalic acid, 192 116 13. Hyposulphonaphthalic acid. 193 118 14. Benzosulphuric acid. 194 119 15. Sulphocetic acid, .... 195 120 16. Sulphoglyceric acid. 196 120 1 7. Sulphoindigotic and hyposulphoindigot ic aci ds, 197 122 18. Stearin, ...... 201 "\ 122 19. Olein, 202 ■i 124 20. Hyponitromeconic acid, 202 124 21. Xanthic acid. 203 125 22. Formobenzoilic acid, 206 127 Chap. VII. Of cyanogen and its compounds, 207 128 Sect. 1. Cyanuric acid, 208 129 2. Cyanic acid, . . . • 209 133 3. Insoluble cyanuric acid. 210 137 4. Cyanilic acid, 211 138 5. Allantoic acid, . . . 212 140 6. Uric acid, .... 214 140 Appendix. Method of detecting vegetable acids, 214 141 142 Class II. Vegetable Alkalies, 221 143 Chap. I. Of alkalies analyzed, 222 144 Sect. 1. Menispermina, 223 145 2. Cinchonina, 225 146 3. Quinina, 230 146 4. Aricina, 237 147 5. Salicin, 239 153 6. Veritrina, 241 156 7. Sabadillina, 243 156 8. Thebaina, 244 157 I 9. Delphina, 246 157 I 10. Narceina, 248 158 1 11. Codeina, 250 159 ■ 12. Strychnina, 252 159 ■ 13. Brucina, 258 160 ■ 14. Emetina, 262 162 ■ 15. Solanina, 264 164 ■ 16. Narcotina, 265 165 ■ 17. Morphina, 267 167 ■ 18. Atropina, 273 168 1 19- Conicina, ■ 20. Pnrillinn, 276 278 ^^rrr:U'^mmr»SiT4 III P'ff! X CONTENTI!. • PikUB Sect. 21. Meconin, 279 Chup. II. Alkalies imperfectly examiaed, 282 Sect. 1. Jervina, « . 282 2. Digitalina, 283 3. Nicotina, 284 4. Curarina, 286 5. Corydalina, 287 6. Jamacina, 289 7. Surinamina, 290 8. Cathartina, 290 [). Guaranlna 291 10. Hurina, 292 1 1 . Sanguinarina, 292 12. Violina, 293 13. Esenbekina, 293 14. Buxina, 293 15. Eupatorina, 294 16. CrystlUina, 294 17. Theina, . 295 Appendix. Method of detecting alkalies, 296 Class III. Intermediate Bodies, 300 Chap. I. Alcohol and its compounds 300 Sect. 1. Aldehyde, 301 2. Compounds of aldehyden, 307 3. Acetal, 309 4. Deuto-carbohydrogen, 310 5. Chloroform, 312 6. Bromoform, 314 7. Iodoform, . 315 8. Chloral, . 316 9. Bromal, 320 10. Ethal, 321 Chap. II. Of Ethers, 324 Sect. 1. Mercaptan, 325 2. Hydrocyanic ether, 328 3. Sulpholiydric ether, . 328 4. Carbonic ether. 330 5. Oxalic ether, 332 6. Succinic ether. , 333 7. Acetic ether. . 334 8. Citric ether. . 335 9. Mucic ether, , 337 1 0. Pyrocitric and pyrotartaric ether s, 338 1 1 . Pyromucic ether, 339 12. Suberic ether, . 340 13. Qinanthic ether, 341 14. Chlorocarbonic ether. 342 15. Cyanic ether, , 343 If). Chlorocyanic ether, . 344 1 7. Elaidic ether, . 345 Chap. III. Of Pyroxylic spirit and its compounds, 346 IV. Of Acetone, , , 362 PAUK 279 282 282 283 284 286 287 289 290 290 291 292 292 293 293 293 294 294 295 296 300 300 301 307 309 310 312 314 315 316 320 321 324 325 328 328 330 332 333 334 335 337 338 339 340 341 342 343 344 345 346 362 CONTENTS. XI PACE Chap. V. Of Mesite, 365 VI. Of Colouring matters, 367 Division I. Of Blue colouring matters, 367 Sect. 1 . Of Indigo, 367 2. Litmus or turnsole, . 384 3. Blue flowers. 386 Division II. Of red colouring matters, 387 Sect. 1. Madder, . 387 2. Archil and cudbear, . 399 3. Safflower, . 405 4., Logwood, 407 , 5. Brazil wood. 409 6. Red Sanders, 410 7. Cactin, 411 8. Red flowers, 412 Division III. Yellow colouring matters. 412 Sect. 1. Quercitron bark, 412 2. Old fustic, 413 3. Weld, 415 4. Persian berries, 416 5. Anotta, 417 6. Turmeric, 419 7. Saffron, 421 8. Sumac, 422 9. Rhein, 423 10. Chaya-ver, 423 1 1 . Yellow flowers, . 423 Division IV. Of green colouring mattei fS, 425 Sect. 1. Chlorophyllite, 425 2. Sap green. 426 3. Coffee green. 426 Division V. Of white flowers. 427 Chap. VII. Of fixed oils, 427 Division I. Of drying oils, . 428 Sect. 1 . Linseed oil. 428 2. Oil of walnuts, . 429 3. Oil of hempseed. 429 4. Poppy oil, 430 5. Castor oil. 430 6. Croton oil. 433 Division II. Of fat oils, 433 Sect. 1. Olive oil, . 434 2. Oil of almonds, 438 3. Rapeseed oil, 438 4. Oil of colza, 439 5. Oil of mustard, 439 6. Tea oil, 439 7. Laurel oil, 439 8. Oil of alysum, . 440 Division III. Of solid oils. 440 Sect. 1 . Butter of cacao, 440 2. Palm oil, . 440 r" xu CONTENTS. FAOa Sect. .3. Touloucouna oil, .... 441 4. Butter of nutmeg', .... 441 5. Coooa nut oil, ..... 442 6. Butter of illipe, .... 442 7. Bees' wax, 443 8. Myrtle wax, ..... 446 9. Brazil wax, ..... 447 10. Japan wax, 447 1 1 . Fossil wax of Moldavia, 448 12. Galactin, 448 13. Wax of ceroxylon andicolo, 450 Chap. VIII. Of Volatile oils, 452 Divi'jion I. Of light volatile oils, 453 Sect. 1 . Oil of turpentine, .... 453 2. Oil of lemons, ..... 459 3. Orange flower oil, .... 461 4. Juniper berry oil, .... 463 5. Oil of pepper, ..... 464 6. Oil of sabinc, ..... 464 7. Oil of thuya occidentalis, . 465 Division II. Of Volatile oils containing oxygen, . 465 Sect. 1 . Oil of cloves, 465 2. Oil of cinnamon, .... 469 3. Oil of bitter almonds. 469 4. Oil of bergamotte, .... 472 5. Oil of roses, 472 (). Oil of jonquille, .... 473 7. Oil of peppermint, .... 473 8. Oil of avender, .... 474 9. Oil of rosemary, .... 474 10. Oil of anise, ..... 475 1 1 . Oil of cajeput, ..... 476 12. Oil of mint, 476 13. Oil of fennel, 476 14. Oil of dill, 477 15. Oil of chamomile, .... 477 1 6. Oil of nutmegs, .... 477 1 7- Oil of tansey, ..... 478 1 8. Oil of asarum, ..... 478 19. Oil of caraways," .... 478 20. Oil of pimento, 478 21. Oil of parsley, ...... 478 22. Oil of sassafras, .... 479 23. Oil of basil, 480 24. Oil of hops, 480 25. Oil of whisky, . , . . . 481 2fi. Oil of brandy, 481 27. Oil of potatoes, ..... 481 Division III. Of aci'id and vesicating oils, 482 Sect. 1. Oil of mustard, ..... 482 2. Oil of horse radish. . . . . . 484 3. Oil of scurvy grass. . . . . . 485 9 441 441 442 442 443 446 447 447 448 448 450 452 453 453 459 461 463 464 464 465 465 465 469 469 472 472 473 473 474 474 475 476 476 476 477 477 477 478 478 478 478 478 479 480 480 481 481 481 482 482 484 485 f CONTENTS. Xiii . PAQR Sect. 4. Oil of garlic 485 Division IV. Of camphors, 487 Sect. 1. Common camphor, 487 2. Camphor from oil of peppermint. 493 3. Camphor from oil of anise, 493 4. Camphor from oil of cubebs. 494 5. Asarin, ..... 495 Appendix, Sect. 1. Helenin, . 498 2. Betulin, . 498 3. Nicotianin, 498 4. Anemonin, 499 Chap. IX. Of Resins, .... 500 Division I. Of Balsams, 505 Sect. 1. Turpentine, 505 2. Copaiva, .... 510 3. Balsam of Peru, 516 4. Balsam of Tolu, 520 5. Liquid sty rax, . 520 6. Opobalsamum, . 523 7. C lina varnish, . 525 Division II. Solid Resins. 525 Sect. 1. Rosin or colofan, 525 2. Mastich, .... 528 1 3. Sandorach, 529 '% 4. Elemi, .... 531 M 5. Tacamahac, 532 a 6. Labdanum, 532 ■ 7. Botany bay resin, 532 ■m 8. Black poplar resin, 533 9. Guaiacum, 5.34 10. Storax, 537 1 1. Dragon's blood, 537 12. Dammara, 538 13. Resin of Jalap, . 540 14. Benzoin, 540 15. Anime, 542 16. Copal, 543 17. Highgate resin. 550 18. Lac, 550 19. Amber, 557 20. Pasto resin. 562 ■ 21. Of Varnishes, . 563 ■ Chap. X. Of Gum Resins, 566 I Division I. Fetid Gum Resins, 567 ■ Sect. 1. Ammoniac, 567 ■ 2. Galbanum, 569 I 3. Asafoetida, 570 1 4. Opoponax, 571 I 5. Sagapenum, 572 ■ Division II. Stimulating Gum Resins, 574 H Sect. 1. Olibanum, 574 ■ 2. Myrrh, 575 H 3. Euphorbium, 576 XIV CONTENTS. ].;■ um Sect. 4. Bdellium, . Division III. Cathartic Gum Kesins, Sect. 1. Aloes, 2. Scammony, 3. Gamboge, Division IV. Sedative Gum Resins, Sect. 1. Opium, 2. Lactucurium, 3. Upas, Class IV. Neutral Vegetabu: Principles, Chap. I. Of Amides, or Amidets, Sect. I. Oxamide 2. Oxttmethane 3. Succinamide 4. Benzamide 5. Benzimide 6. Asparamide 7. Urethun or ethercarbamide 8. Sulphamide Chap. 11. Benzoyl and its Compounds Sect. 1. Benzoyl, 2. Hydret of benzoyl, 3. Benzoin, 4. Benzoic acid, 5. Chloride of benzoyl, . 6. Bromide of benzoyl, . 7. Iodide of benzoyl, 8. Sulphuret of benzoyl, 9. Cyanodide of benzoyl, 10. Benzone, . 1 1. Benzin, 12. Nitrobenzide, 13. Suljihobenzide, 14. Azotobenzide, Chap. III. Of Spiroil and its Compounds, Sect. 1. Hydrospiroilic acid, 2. Chloride of spiroil, 3. Bromide of spiroil, 4. Iodide of spiroil, 5. Spiroilic acid, . Chap. IV. Of Sugars, Sect. 1. Common sugar, 2. Liquid sugar, 3. Sugar of grapes, 4. Mushroom sugar, 5. Manna, 6. Liquorice sugar, 7. Sugar of figs, 8. Sarcocollin, 9. Glycerin, . Chap. V. Of Amylaceous Substances Sect. I. Common Starch, 2. Hordein, . Mai 578 579 579 581 582 584 584 587 587 590 590 590 592 593 594 596 597 598 600 601 603 604 604 605 605 606 607 607 607 608 609 610 611 612 613 613 617 618 618 618 620 620 636 636 639 640 642 644 645 645 649 650 fi57 578 579 579 581 582 584 584 587 587 590 590 590 592 593 594 596 697 598 600 601 603 604 604 605 605 606 607 607 607 608 609 610 611 612 613 613 617 618 618 618 620 620 636 636 639 640 642 644 645 645 649 <;50 657 M I ll CONTENTS. XV S .'.t, 3. Liclieuin, ....... PAai 658 4. Iiuilin, ....... 660 5. liignin, ....... 661 6. Fungi n, ....... 665 7. Diastufle, ....... 666 8. Olivilin, 668 9. Columbin, ...... 669 Chap. VI. Of Gums, 670 Sect. 1. Arabin, 671 2. Bussorin, ....... 674 3. Cerusin, ....... 677 4. Culendulin, ... . . . 678 5. Saponin, ....... 678 Chap. VII. Of Glutinous Substances, . . . . 680 Sect. 1. Albumen, 681 2. Emulsin, ....... 682 3. Mucin, 683 4. Glutin, 684 5. Zein, ....... 685 6. Viscin, ....... 686 7. Pollenin, ....... 689 8. Legumin, ....... 690 9. Aniygdalin, 691 10. Glairin, 693 Chap. VIII. Of Caoutchouc, 694 IX. Of Extractive, ..... 702 X. Of Bitter Principles, .... 704 IX. Of Products of the Destrictive Distillation of Vegetable Substances, 718 Sect. 1. Persian naphtha, .... 719 2. Coal naphtha, 720 3. Petrok'ue, ..... 721 4. Asphalene, 722 5. Paraffin, ...... 723 6. Eupion, ...... 725 7. Creosote, ...... 728 8. Ampelin, 733 9. Picamare, 733 10. Pittacall, 735 1 1 . Capnomore, ..... 735 12. CetU-iret, 737 13. Naphthalin, 738 14. Paranaphthalin, .... 746 15. Idrialin, ...... 748 16. Eblanin, 750 17. Lamp black, ..... 751 18. Animal charcoal, .... 754 Chap. XII. Of Neutral Compounds, often contaiaing Azol .e, 757 Sect. 1. Staphysin, ..... 757 2. Caftein, 758 3. Piperin, ...... 760 4. Daphnin, ...... 761 5. Jalapin, ...... 762 6. Sinapin, ...... 762 '1 \\i 1st,. xvi CONTENTS. Moa Sect. 7. Coumariii, 763 8. IIi'Hporidiii, 765 y. Populin, 766 10. riiimbagin, 767 Chap. XIII. Of Melon, ami some anulof^ous Comp oundi of Azote, 768 Sect. 1. Sulphurct of cyunogoii, 768 i 2. Melon, 768 3. Melani, 772 4. Melaniin, .... 774 5. Animelin, . . • . 776 (]. Aniinelide, 779 7. Chloriile of cyanogen. 780 8. Cyanamide, 781 9. The potash salt. 782 10. Nitrosulphuric acid, . 783 DIVISION II. OF THE PARTS OF PLANTS. 786 ChaiJ. I. Of the Sap of Plants, 786 II. Of the peculiar Juices, 790 III. Of the Gases in Plants, 796 IV. Of Barks, .... 797 V. Of Roots, .... 812 VI. Of Bulbs, .... 838 VII. Of Woods, 848 VIII. Of Pith, .... 853 IX. Of Leaves, 853 X. Of Herbaceous Plants, 863 XI. Of Flowers and Pollen, 867 XII. Of Seeds and Fruits, 875 Xin. Of Ferns, 929 XIV. Of Lichens, 932 XV. Of Mushrooms, 936 XVL Of Algjo, 943 XVIL Of Diseases of Plants, 946 DIVISION in. OF VEGETATION. . 949 Chap. I. Of the Structure of Plants, .... 946 II. Of the Temperature of Plants, 955 III. Of Germination, 961 IV. Of the Food of Plants, 967 V. Of the Motion of the Sap, 980 VI. Of the Functions of the Leaves, 988 VII. Of the Peculiar Juices of Plunts, . 1003 VIII. Of the Decay of Plants, . 1007 DIVISION IV. OF DECOMPOSITION OF PLANTS, 1009 Chap. I. Of the Vinous Fermentation, . . . . 1011 Sect. 1. Of Beer, . 1011 2. Of Wine, . 1022 Chap. II. Of the Panary Fermentation, 1028 III. Of the Acetous Fex'mentation, . 1032 IV. Of Putrefaction, . 1035 Appendix . 1039 PAOK 7()5 7<)<) 767 3,768 768 768 772 774 776 771) 780 781 782 783 786 786 790 796 797 812 838 848 853 853 863 867 875 929 93'i 936 943 946 949 946 955 961 967 980 988 1003 1007 k :s, 1009 1011 1011 1022 1028 1032 1035 1039 INTRODUCTION. All substances, so far as we have an opportunity of examining them, belong to one or other of the three kingdoms of nature, distinguished by the names of the mineral, vegetable and animal kingdoms. The bodies belonging to the first of these have been described, as far as their chemical properties are concerned, in the preceding volumes of this work. We come now to the Chemistry of vegetable and animal bodies. It is well known that every vegetable and animal constitutes a machine of greater or less complexity, composed of a variety of parts dependent on each other, and acting all of them to produce a certain end. Vegetables and animals on this account are called organized beings ; and the chemical constituents of which they are composed are called the constituents oi organized beings or organized bodies, to distinguish them from the constituents of the mineral king- dom, which consist merely of aggregates of atoms combined together without constituting an organized structure. The chemical principles of which animals and vegetables are composed are exceedingly numerous. But we can seldom obtain them in a state of such purity as to enable chemists to examine their properties with accuracy, unless when they are capable of crys- tallizing or of entering into definite compounds with acids or alkalies. Hence the great difficulty which has attended the investi- gation of oils, glues, albumen, &c., which we have no means of pro- curing in a state of absolute purity. The chemical principles of organized bodies are all compounds, and consist sometimes of two, sometimes of three, and sometimes of four, simple bodies united together ; but seldom of more. These simple bodies are hydrogen^ carbon, oxygen and azote, which may be considered as constituting, in a great measure, the basis of the ani- mal and vegetable kingdoms. I. Organized principles composed of two ingredients are of four kinds. (I.) 1. Composed of hydrogen and carbon. Thus oil of turpen- tine is a compound of C" H** * The atom of the different simple bodies is denoted by the first letter of the name, or in certain cases by two or even three letters to prevent ambiguity, and the number of atoms of each by the figure placed on the right side of the letters. Thus C" H" means a compound of 10 atoms carbon 8 atoms hydrogen. B . miij:: ._ 9 IMIlonUCTION. Il i: I '2. ri)ni]M)sc(l of liydnigcn nml oxyp[en. Thua water in a com- pound of II (). 3. Of ciirhon niul oxj-,','oii. Tlmx oxalic nci.l is n coiiipouiul of 4. Of rarhoii and nzoto. Thus cyanojron in C^ Az. Organized principles foniposcd of throe constituenta arc nnich more nuniorouH than those composed of two. 1. The nioHl ennniion eonstitnentrt are carfxm^ fiydmgrn and oa*;/- gcu. The greater mnnher of the acid?*, alcohol, ethers, sngarn, gums, &c., are thus conHtitutcd. When carlxm is saturated with oxygon it united with two atoms, and the union is attended with tlio phenomena of conduistion. Hydrogen by cond)nHtion forms water containing one atom of hydrogen united to one atom of oxygen. But in organized principles containing hydrogen, carhon and oxygen, the oxygon never amounts to so nuich as three atoms for two atoms ol' the other constituents. Sometimes it is enough to convert the hydrogen into water, or the carhon into carbonic acid, but never to convert both at once into water and carbonic acid. Hence it happens that all these compounds of throe ingredients, though they contain oxygen, arc still combustiblo. When heat is applied to them, if we raise it to a certain point, which is different in each body, a portion of carbon unites to a portion of oxygen, and flies off in the state of carbonic acid, or a portion of oxygon unites to hydrogen and escapes under the form of water. What remains is a new organized principle. 2. Some few organized bodies are composed of carbon, hydrogen, and azote. Thus azulmic acid seems to be C H Az'. 3. Some are supposed to be composed of carbon, azote, and oxy- gen. Thus carbazotic acid is C"' Az^ O''*. The organic principles composed of four constituents, consist of carbon, hydrogen, azote and oxygen united in various proportions. Thus aspartic acid is C** H^ Az O". AKnost the whole of the alkaloids contain these four constitucntf;. The number of atoms of azote coDtained in these compounds is generally small compared with that of the other three constituents. And there is almost always a great preponderance in the atoms of carbor and hydrogen over those of azote and oxygen. The richest body in azote known is melon, which is composed of C* Az^. It has been supposed by some chemists that there is an essential differeni between the affinities which unite the atoms constituting organic princi|)les, and those which unito the atoms of unorganized h I i T The meaning of the letters will bo uiidcratoo C is carbon H is hydrogen Az is azote (I i^ oxygrcii Chi. 1,' chlorine Br is S.ic'T.'.nc. oy the following tabic ■ - I is iodine S is sulphur N is sodium K is potassium Ph is phosphorus. INTUODLM TKIN. 3 mds is Itucnts. tonis of I richest bscntial Tituting janized bodies— that tlicro is somo imkii \\i\ powcM'bodulod i-licMiiicalnttiuity, which intiTtoPLM with, luid rcjfuiaUM the comhiiiutioiw and docom- ])ositioiis of or;jraui/('(l Ixidicn, w'liich i.s wantiii'j; in thonc that aro uti()i';;aii!/ed. Hut I can sec no uvidcnco tor any Huch opinion. Th(! /i^roat dillcrcnco between the tw" chi3sc3 of bodicM consists in this, that the orjfani/ed arc? nnich mor«' < ouijilicated in their struc- ture, oontainin<;' ii nnieh j,M'oater number of atoms than the unor^ran- ized. Hence they aro nuich more uii^^able, much more easily decomposed, and nmch more liable to iln ouipositiou than unor- ganized bodies. Hut tiie reason of this I consider to bo very obvious. Organic principles aro made by the processes connected with vegetable and animal life. They constitute the results pn.i-eedinfjf from the chemical skill of the Creator of plants and animals, which »s in- finitely greater than ours can pretend to be. 13ecauso wo have not hitherto b( on ibL* to make eompounds consisting; of the various atoms coii-iti.ui ijg mineral bodies, as complicated as those which exist in M'l- ini, il and vegetable kingdoms, it does not follow that Buch ooD.plicatcil compounds^ are impossible, or that they may not here "tc '>'.i produced as chemical skill improves. It Is very pro- bible thai silicon, the metals, sulphur, chlorine, bromine, iodine, pUosphorus, &c., will hereafter give rise to bodies as complicated in their structure as the vegetable acids, alkaloids^ oils, resins, sugars, and other organized comj)ounds, which at present appear to ditler so far from mineral compounds. Nor is it at all unlikely that chemists may hereafter acquire skill enough to be able to form, artificially, the various organic principles, such as sugar, gum, &c., which at present are obtained ready formed from the vegetable or animal kingdom. The prevailing opinion at present among chemists is, that binary compounds alone exist: that is to say, that one electro-negative atom is only capable of combining with one electro-positive atom. Two of these binary compounds may combine together, making a new binary compound consisting of four atoms. Two of these new binary compounds may cond)ine with each other, making a new binary compound consisting of eight atoms. And in this way binary compounds may be formed as complicated as any that exist. But I do not see the evidence upon which this opinion rests. The most stable of the unorganized principles indeed as barytes, lime, stron- tian, magnesia, potash, and soda, are binary compounds, being com- posed each of an atom of oxygen united to an atom of the respec- tive metals, which consiitute the bases of these bodies. But suljdiuric icid, which is -scarcely less stable than these bodies, is quaternary compound, being composed of one atom of sulphur united to three atoms of oxygen, and nitric acid is a sextenary compound of one atom of azote with five atoms of oxygen. Now, I cannot conceive any rt^ison for not believing, that in sulphuric acid the three atoms of oxyj^on surround the atom of sulphur in the :h ^1 4 INTnODUCTION. way long ago suggested by Mr. Dalton, forming a complex atom, which may be represented thus, -^ in which ® represents an atom •2 H* 0*+Br H^ 0*+ I H2+0 H2+0« The oil or hydret Chloride of spiroil Bromide of spiroil Iodide of spiroil . . . C* Spiroilic acid . . . C'^ Analogy leads to the inference that other (probably all the) vege- table acids have, like benzoic acid, a base, and that the acid is a com- pound of that base with oxygen. Thus, since Peucedanin is .... C'' Succinic acid . . . . C"* Malic and citric acids ' . . C"* Tartaric and racemic acids . . C* may it not be inferred, that they have for a common base C* H The common base of the alkalies, cinchonina, quinina, and are- cina, seems to be C^" H'^ Az. Cinchonina is . . . C"" H'" Az+O'i Quinina . . . . C^" H'^ Az+O^ Arecina . . • . C^" H'^ Az+O^ 3. Theory of Ethers. A discussion respecting the constitution of ethers has been carried on with much animation, between M. Dumas on the one side, and M. Liebig on the other. According to Dumas, the base of ether is C* H^ ; or what I distinguished in the Chemistry of Inorganic 2 o I '3' ■I f: ^il! an .4 H2 ? id are- Icarried lie, and l)t" ether organic ! if' f VEGETABLE BODIES. 9 Bodies by the name of tetarto-carbohydrogen. Sulphuric ether is C* H*+HO; oxalic ether is (C^ n*+llO)+C^ oK and so on of the others. AccordinjT to Liebig on the other hand, the radical of ether is C* H^. Sulphuric ether is an oxide of C* H^, and is represented by C* H^+O: or (for shortness' sake) by C* R^ O. Alcohol is a hydrate of sulphuric ether, or C'' H^ O+HO. The radical of ether, or C^ H'', is capable of combining with chlo- rine, bromine, and iodine, and forms chloric, bromic, and iodic ethers, composed as follows : — Chloric ether . . . C* H^ 3 Chi Bromic ether . . . C* W+ 2 Br Iodic ether . . . . C* H«-i- 2 1 All the oxygen acid ethers are combinations of an atom of sul- phuric ether, which possesses the characters of a base with an atom of the acid. Thus, Nitrous ether is C* H» O+Az 0' Acetic ether C* W 0+C* W 0^ Oxalic ether C^ W O+C^ 03 Benzoic ether C^ H^ 0+C'^ H5 0' Formic ether C^ H« 0+C2 H 0' Mucic ether C^ H» 0+C6 H^ O^ Citric ether C* H' 0+C^ H2 O* Succinic ether C* W 0+C* H2 0' Chlorocarbonic ether C^ H« O+C^ Chi 0^ Chlorocyanic ether C* H5 0+C2 Az Chi. CEnanthic ether C^ H' O+C* H13 02 W 0+2 (S O') W 0+2 (Ph O^*) H^ 0+2 (C2 03) H« 0+2 (C^ H2 OO What have been considered as alcohol acids are merely combinations of one atom of ether acting as a base with two atoms of the acid. Thus, Althionic acid is . C* Phosphovinic acid . C* Oxalovinic acid . C* Tartro-vinic acid . C'' They ought rather to be considered as salts, consisting of two atoms acid united to one atom base than aa acids sui generis ; ac- cordingly one atom of barytes added to an integrant particle of each of these acids renders them neutral, because the atom of ether neutralizes the other atom of the acid present. Of these two views, I am disposed to prefer that of Liebig as the simplest, and as agreeing best with the phenomena. Liebig has extended his theory much farther, and made it apply to sugars, mercaptan, xanthic acid, &c. Common sugar is . . . C'^ Now it is resolvable into 2 atoms ether . . . . C* 4 atoms carbonic acid . . . C'* H'« 0-" H 10 O^ 0« Qli HIO O'O 1 fijl I: th ■''■ . I 1- i ii I: 10 VEGETABLE nODIES. We may, therefore, represent common sugar by this formula : 2 (C* H» 0)+4 (CO^). Anhydrous sugar of grapes is C" H'^* O'^. It may be repre- sented by 2 (C* H« 0)+4 (C02)+2 (HO), and common grape sugar is 2 (C^ H» 0)+4 (CO'0+4 (HO). Mercaptan is C* H^ S H (sulphuretted hydrogen). And xanthic acid C* H« 0+2 (S=» C) (bi-sulphuret of carbon). Alcohol is C* H" 0+HO. 4. Theory of Pyracids. There are several vegetable acids which, when distilled, undergo decomposition, and new acids are generated by the process, which have been distinguished by the name oi pyracids. Thus tartaric acid, when so treated, yields/? yrotartaric acid ; mucic acid gives pyro' mucic ; gallic, pyroffallic, and kinic, pyrokinic acid. Now, M. Pelouze has observed, that the nature of the decompo- sition is regulated by the degree of heat applied. When the heat is not too high, the acid is resolved into a pyracid, carbonic acid and water, or sometimes into a pyracid, and one or other of the two last products. Thus, when tannin is distilled at a heat of 482°, it is resolved completely into cmbonic acid, water, and metagallic acid. Tannin being C'^ H« O'S 3 atoms of tannin are C" H^* 0^\ Now these three atoms are resolved by the heat into 6 atoms carbonic acid = C* O^^ 8 atoms water = H^ O^ 8 atoms metagallic acid = C^^ H'« O'^ C54 H24 036 When gallic acid is distilled at 419°, it is converted into pyro- gallic acid and carbonic acid. Gallic acid is . C7 H^ 0« Pyrogallic acid is Carbonic acid is c W 03 02 C7 H^ O^ At the temperature of 482° no pyrogallic acid is formed, but only metagallic acid, water and carbonic acid. 1 atom gallic acid is . C W O^ 1 atom metagallic acid = C" H^ O^ 1 atom carbonic acid ="- C O^ 1 atoui water = HO C^ W 0= When malic acid is distilled at a low heat, it is resolved into maleic acid and water. 'f 'mula : rcpre- grape irbon). ndergo , which ic acid, 5 pyro- compo- he heat icid and two last i°, it is c acid. :o pyro- )ut only led into VEGETAHI-E UOUIES. Malic acid is . . C* 11'^ O^ Maleic acid Water = C* H O' = II O C* H» O* When acetate of barytes is distilled, the acid is resolved into carbonic acid, which remains combined with the barytes and pyro- acetic spirit or acetone. Acetic acid is . . C* H' O^ Acetone is Carbonic acid is C IP O C O'' C* H' 03 Sometimes the saturating power of a vegetable acid is not altered by converting it into a pyroacid ; sometimes, according to Pelouze, it is reduced to one-half.* From these very important and curious observations, for which we are indebted to M. Pelouze, it has been inferred, that gallic acid is a compound of pyrogallic acid and water, and so of the rest. But I cannot see upon what evidence that opinion rests. An atom of tannin cannot be resolved into metagallic acid, carbonic acid and water, though these are the products when the acid is distilled at 482°. It is much more probable, that by the temperature applied, a certain portion of the carbon, or hydrogen, or of both, undergoes combustion, and that the remaining atoms arrange themselves so as to constitute the pyroacids. 5. Theory of Substitutions. Oxygen, chlorine, bromine and iodine may be made to unite with various conipound bodies, while at the same time these bodies give out hydrogen. Thus when dry chlorine gas is passed into pure oil of bitter almonds, which is composed of C^* H^ 0^+H, it loses its atom of hydrogen which constituted it a hydret, for which an atom of chlorine is substituted, making a compound consisting of Q14 JJ5 o^+Chl. which is a chloride of benzoyl. Dumas has gene- ralized this and various analogous facts, and drawn from them the following general conclusions : — 1 . When a body containing hydrogen is subjected to the dehy- drogenizing action of oxygen, chlorine, bromine, or iodine, for every atom of hydrogen that it loses it gains an atom of oxygen, chlorine, bromine or iodine. 2. When the hydrogenous body contains water, this last body loses its hydi'ogcn without any thing being replaced. If, after this, any hydrogen be abstracted, it is replaced by a corresponding num- ber of atoms of oxygen, chlorine, &c. Ann. tic Chiin. ct dc Pin?. Ivi. 303, I .. B I id 12 VEUUTAULU BODIES. Dumas gives the following examples of these rules : — (I.) Dry oxalic acid is C^ O'+H O. That is to say, an atom of oxalic acid and an atom of water. The water, when the acid is treated with nitric acid, loses its hydrogen, and there remains C^ OS that is two atoms of carbonic acid, into which it is well known that oxalic acid is converted by the action of nitric acid. I think that the phenomena would be explained in a simpler way in this case by considering the water of the oxalic acid to be inert, and that the nitric acid gives out an atom of oxygen to the anhyd^ rous oxalic acid, and thus converts it into carbonic acid. For if we take crystallized oxalic acid composed of C^ 0^+3 H O the result is the same. Here two atoms of the combined water are admitted to be inert. Why should they not all three be in the same predica- ment ? (2.) Formic acid by the action of oxides of mercury or silver is converted into carbonic acid. Formic acid is C^ H O"^. Here the oxygen of the oxides forms water with the hydrogen of the acid, and adds an atom of oxygen, making C^ O*, which is two atoms of car- bonic acid. (3.) Alcohol, by the action of the atmosphere, h converted into acetic acid. Alcohol is C* H^ 0-hH O, and crystallized acetic acid is C^ H^ 0^+H O. Here, if we neglect the atom of water in both, which is not affected by the action, we see that two atoms of hydrogen are replaced by two atoms of oxygen. So that the change corresponds exactly with Dumas' law. (4.) Alcohol, by the united action of sulphuric acid and binoxide of manganese, is converted into formic acid. Alcohol is C* H^ O -f-H O. If four atoms of the hydrogen are replaced by four atoms of oxygen we have C'* H^ O", which is two atoms of formic acid. (5.) The chloride of olefiant gas, usually called Liquor of the Holtanders, is a compound of C^ H^ Chi or C^ H* ChF. When mixed with chlorine gas and exposed to the action of solar light it loses all its hydrogen, which is replaced by as many atoms of chlorine, and it becomes C* ChP or sesquichloride of carbon. (6.) When hydrocyanic acid is exposed to the action of chlorine, it loses its atom of hydrogen, which is replaced by an atom of chlorine. Hydrocyanic acid is C^ Az+H. It becomes C^ Az+ Chl or chlorocyanic acid. (7.) The essential oil of cinnamon is converted by the action of the air or oxygen gas into cinnamonic acid. Oil of cinnamon, ac- cording to the analysis of Dumas and Peligot, is C'** H'-* O^ and cinnamonic acid is C"* H"^ O^. Here it loses H'^ and gains O, which does not quite agree with Dumas' theory. But I consider the true composition of the oil of cinnamon to be C* H^ O^, which would bring it under the formula. These examples are amply sufficient to explain the nature of Dumas' empyrical formula. Were it to hold universally, it would indicate, either that the bodies which undergo such changes were J VEGETABLE BODIES. IS I atom acid ia jmains 13 well id. er way inert, anhyd- ir if we 5 result Imitted . iredica- silver is lere the cid, and } of car- ted into d acetic water in itoms of ; change binoxide H^ O ir atoms acid. );• of the When light it chlorine, chlorine, atom of Az+ iction of ion, ac- O^ and jains O, [consider which hydrets, or at least that hydrogen ia the principle most easily acted on by the supporters of combustion. M. Laurent has given us a theory of organic combinations, in some respects the same as that of Dumas ; but more extended.* He considers the base or radical of every organic body to be a com- pound of carbon and hydrogen united together, so that the atoms of the carbon bear a simple relation to those of the hydrogen : the series which he gives are the following : — Carbon, 1, 5, 2, 3, 5, 10 Hydrogen, 1, 2, 1, 2, 4, 7 In the first, the number of atoms of the carbon in the radical are equal to those of the hydrogen ; in the second they are as 5 : 2 ; in the third as 2 : 1 ; in the fourth as 3 : 2 ; in the fifth as 5 : 4 ; and in the sixth as 10 : 7. When these radicals iire subjected to a dehydrogenizing pro- cess, as by passing a current of chlorine through them, they gradu- ally lose their hydrogen or a part of it, but gain as many atoms of H the dehydrogenizing body as they lose of hydrogen. So that if we add the number of atoms c ' the new body to those of hydrogen remaining the sum will make up the number of atoms of hydrogen originally present in the radical. The dehydrogenizing body, or a part of it, being converted into water, nitric acid, muriatic acid, &c., may either be disengaged or remain combined with the new compound formed. The fundamental radical and its derivatives will be neutral or alkaline, whatever be the portion of oxygen, hydrogen, chlorine, &c., entering into it. But when the oxygen, &c., enters into combina- tion with the radical, it renders it acid, how small soever the uniting portion may be. Those bodies which enter into combination without being a part of the radical, may be removed by heat, alkalies, &c., without being replaced by any thing else. But when a body constitutes a part of the radical, this cannot be done. These are the most important points in M. Laurent's theory. It is not possible to illustrate it by examples, without entering into discussions which would lead us too far. * Ann. de Chim. et de Phys. Ixi, 128. lature of lit would jes were DIVISION I. or VEGETABLE PRINCIPLES. It will bo sufficient in the present state of our knowledjre, to arrange those which are very numerous, under the four following classes : 1 Acids, IJ Intermediate bodies, 2 Alkalies, 4 Neutral bodies, These will be described in succession under their respective heads. CLASS I. OF VEGETABLE ACIDS. n^i f A considerable number of the acids belonging to the vegetable kingdom, were described in the Chemistry of Inorf/anic bodies, (vol. ii. p. 45). Rut so much has been done on this subject since the year 1831, when that work was published, thfit it will be necessary to resume the account of them here, referring to the former work for every thing which does not require to be corrected or amended. The acids derived from the vejjetable kingdom which have been recognised by modern chemists, and more or less accurately examined, amount to about 116. These acids are all composed of 2, 3, 4 or more constituents ; two of them contain only carbon and oxygen ; namely, Composition, Oxalic, . . C2 O^ Croconic, . . C^ O'* Fifty-seven of them are composed of carbon, hydrogen, and oxygen. One is composed of carbon, hydrogen, and azote ; namely, Azul- mic, C-' H Az^ Two are composed of carbon, azote, and oxygen, namely, Indigotic, . . C» Az* 0« Carbazotic, . . C'^ Az=* O" Five are composed of carbon, hydrogen, azote, and oxygen. There are 16 which, not having been hitherto subjected to chemical analysis, cannot be accurately classified. And, finally, there are 23 acids, which consist of combinations of some other powerful acid, sulphuric acid for example, with alcohol, ether, or some other vege- table principle. In describing these acids, it will be convenient to divide them into sets. Perhaps the following subdivisions into 7 sets may answer our purpose. 1. Volatile Acids or acids which may be volatilized without de- composition. They are 17 in number. 2. Fixed Acids or acids that cannot be volatilized or distilled over VOLATILK ACIDS. It arrange ssos : ) heads. vegetable Hcs, (vol. since the [leccssary iner work amended, lave been xamincd, 2, 3, 4 or oxygen ; d oxygen, .ly, Azul- oxygen. cheniical jre are 23 trful acid, |;hcr vege- .iile thorn lay answer lithout dc- Btilledovcr without docotnposition. They are 34 in nunduM". They consist ol' two divisions. The first are fixed acids, which, wlieu exposed to heat, are decomposed, hut furnish at the same time other acids which liavo been distinguished by the name pi/rncids. These arc 8 in number; and the pyracids whidi they furnish amount to 14. The second division consists of fixed acids whoso pyracids arc unknown. 4. Oili/ acids, or those acids into which oils or wax arc converted when boiled witli potash or soda. The combination of these acids with the alkali constitutes soap. They are 11) in number. 5. Acids containing azote. They are 8 in number. (). Acids imperfectly examined. They are KJ in number. 7. Compound acids, consisting of a vegetable jn'inciplo united to a strong mineral or vegetable acid. They are 'J.'j in number. Let us consider these ditFerent orders of acids in succession. CHAPTER I. VOLATILE ACIDS. It has been already stated, that these acids, so far as our present knowledge extends, are l(i in number. The following table exhibits their names and atomic constitution, so liir as it has been investi- gated. Conititucnta. 1 Oxalic, C^ 0^ 2 Croconic, C» 0* 3 Formic, C» H 03 4 Mellitic, C* H 0* 5 Succinic, C* H^ 03 6 Acetic, C* W 03 7 Lactic, C6 IP 0* 8 Suberic, C« H6 03 9 Naphthalic, C'" H'-^ 0* 10 Sebacic, C>» W 0"' 11 Camphoric, C^o m 03 12 Valerianic, CIO 1^9 03 13 Benzoic, C'^ LP 03 14 Cinnamonic, C'« H^ 03 15 Hippuric, CIS H8 0'^ Az 16 Esculic, C^2 H^6Q24 SECTION I. — OF OXALIC ACID. This acid has been described in detail, in the Ckcmistry of Inor- gallic Bodies, (vol. ii. p. 15). We shall here add the facts respecting it, which have been ascertained since that work appeared. Though it contains only a single base, being composed of two 16 VOLATILE ACIDS ntoina carbon and three atoniH oxypen, yet as it is so easily formed by the action of nitric acid upon a variety of vegetable substances, wo may, without any {jjreat breach of propriety, introduce it here in order to point out what happens when it ia exposed to determinate degrees of heat. 1. It was observed by Dobcroiner that when the crystals of oxalic acid are heated in contact with sulj)huric acid, they arc resolved into equal volumes of carbonic acid and carbonic oxide. The water of the crystals in this case combines with the sulphuric acid, and the other constituents resolve themselves into the two gases just mentioned.* This experiment which has been frequently verified, demonstrates the composition of anhydrous oxalic acid. For 1 volume carbonic acid is . . . CO* 1 volume carbonic oxide is . . . CO Hence oxalic acid is . . . C* O^ 2. Gay-Lussac has made some important experiments on the de- composition of oxalic acid by the naked fire in a glass retort.f When the crystals arc heated to 208" they fuse into a liquid. At 230" a gas is disengaged along with the vapour of water, and the quantity of this gas increases progressively in proportion as the temperature of the acid is elevated by the loss of its water of crys- tallization, between 248° and 2i)i)° the disengagement was very rapid, and it continued till the complete decomposition of the acid with some variations of temperature, which were not exactly marked. If the heat be raised slowly, the whole acid is decomposed. The gas obtained is a mixture of 6 volumes carbonic acid, 5 volumes carbonic oxide. The water distilled over was acid, and owed its acidity to the pre- sence of a quantity of formic acid, formed during the decomposition of the oxalic acid. Now it is easy from the known constitution of oxalic acid and formic acid to explain what happens during this decomposition. Let us suppose 12 atoms of oxalic .icid crystals put into the retort, they are composed 1 2 atoms anhydrous oxalic acid, 36 atoms water, they yield 12 volumes carbonic acid 10 volumes carbonic oxide 1 2 atoms of oxalic acid C«2 QU C" O'" C" O" C" 03« o^ Excess ..... C* But an atom of formic acid is composed of C* H O^. Let us suppose that one of the 36 atoms of water is decomposed and enters into the composition of the fon^ c acid. Water is com- • Schweigger's Journal fiir Chemie und Phjsik, xxiii, 6G. t Ann. de Cliim. et de Phys, xlvi. 218. I I [cid and )Osition. retort, 13 water, imposed is com- Fon.Mic Arm. II ll '/ posed of H O. If we add this to the excess in the oxalic acid over the carbonic acid, and c/irhonic oxide formed, we have C H O*, which 13 an atom of formii icid. Thus, it appears that by tho action of heat oh 12 atoms of oxalic acid, or 94*5 grains, wo obtain Oraln*. 1 2 volumes carbonic acid . . s=33 10 volumes carbonic oxide . . =17*5 1 atom formic acid . . . =: 4*625 35 atoms water .... =39*375 94*5 3. M. Dumas has obtained, by distilling oxalate of ammonia, a substance to which he has given tho name of oxamide* It will be described in a subsequent Chapter of this volume. SECTION II. — OF CROCONIC ACID. This acid has been described in tho Chemistry of Inorqanrc Bodies, (vol. ii. p. 97). It is there stated, on the authority of L. Gmelin, that it is a compound of C" H O*. But it is obvious that a mistake has been committed in the calculation. Gmelin obtained Carbon .... 23*80 Hydrogen . . . . 0*15 Oxygen .... 25*54 Now this is equivalent to 5 atoms carbon . . =3*75 0*18 atoms hydrogen . . =0*0225 4 atoms oxygen . . =4 It is obvious that the hydrogen is too small, to constitute a true constituent. It must have been derived from a little water hygro- metrically present, in the salt analyzed by Gmelin. This opinion I stated in the work referred to. It is at present generally adopted by chemists. Liebig,t found that 100 parts of croconate of potash, when pro- perly dried, yielded, when decomposed by oxide of copper, only 1*08 of water equivalent to j oVod^-^s of its weight of hydrogen. A quantity still smaller than that found by Gmelin, and inconsistent with the notion that hydrogen enters as a constituent into croconic acid. Liebig's analysis of this acid corresponds with that just stated. SECTION Hi. — OF FORMIC ACID. This acid is described in tV>e Chemistry of Inorganic Bodies, (vol. ii. p. 58). Dobereiner has pointed out an economical method of preparing this important acid, which deserves to be stated. Tt is as fol- lows: — Dissolve one part of sugar, starch, &c., in two parts of water, and * An abreviation of oxalic acid and ammonia, because the substance in ques- tion is obtained fioin these two bodies conjointly. f Ann.der Phann. xi. 185. C 18 V(TLATILE ACIDS. mix the solution (in a large vessel) with 2^ or 3 parts of binoxide of manganese in fine powder. This mixture is to be heated to 140°, and then 3 parts of concentrated sulphuric acid, previously diluted with its own weight of water, is to be added by little and little at a time, carefully agitating the mixture after every addition with a wooden rod. After the addition of the first third of the acid, so violent an effervescence takes place, that unless the vessel be at least 15 times the bulk of the mixture, a portion will run over. The effervescence is owing to the rapid formation and evolution of car- bonic acid. At the same time, pungent vapours of formic acid are exhaled. To preserve these the mixture should be made in a copper alembic, the top of which should be put on and connected with the worm in the refrigeratory. When the violence of the eflervescence is over, the rest of the sulphuric acid is to be added ; the mixture is to be agitated, and the whole distilled over almost to dryness. A limpid acid liquid is obtained, having a strong smell, and consisting of water, formic acid, and an etherial liquor. Saturate the formic acid with carbonate of lime, and distil thi liquor a second time to preserve the etherial liquid which comes over with the water, and from which it may be afterwards separated by distilling it off fused chloride of calcium. A pound of sugar yields a quantity of formic acid, capable of saturating 5 or 6 ounces of carbonate of lime. To obtain the formic acid in a concentrated state, evaporate the formate of lime to dryness, and mix 7 parts of this dry salt previously reduced to powder with 1 parts of concentrated sulphuric acid and 4 parts of water, and distil in a retort. The formic acid passes into the re- ceiver. If we substitute 6 parts of alchohol for the 4 parts of water and distil, we obtain formic ether.* Many other vegetable substances besides sugar yield formic acid when treated with binoxide of manganese and sulphuric acid. Ac- cording to Dobereiner, salicin yields it in greater quantity than any other.f M. C. G. Gmelin obtained it in the same way from sugar of mill;, starch, lignin, althea root, mucic acid, &c., and also from alcohol ; but he could not succeed in forming any from acetic acid.J Pelouze has shown that it is formed when hydrocyanic acid comes in contact with muriatic acid, ammonia being formed at the same time.§ Professor Emmet of the University of Virginia, affirms that the binoxide of manganese is of no use in this process. His method is as follows : — Mix together in a retort equal measures of water, strong sul- phuric acid, and clean, but unground, rye, maize, or any other grain. Heat to the boiling point, and as soon as the mass has become thoroughly blackened, add another measure of water, and distil off one measure of formic acid.|| * Ann. de Chim. et de Phys. lii. 108, f Ibid, p. 1 10. 4: Poggendorf 8 Annalen, xvi. 55. § Ann. de Chim. et de Pliys. xlviii. 395. II Silliman's Jour, xxxii. 140. MELLITIC ACID. 19 lit the lod is sul- ^rain. [come I distil 395. Dobereiner has pointed out a. strikiti": character of formic acid, by which its presence may be easily ascertained. When formic acid or formate of soda is put into a solution of any salt of gold, platinum, or silver, an effervescence takes place, carbonic acid is given off, and the gold, platinum, or silver is deposited in the metallic state.* When we mix formate of soda with a solution of corrosive sublimate, calomel is precipitated. Advantage might readily be taken of this imj>ortant property to separate gold, platinum, or silver from other metals with which they may be in combination. When formic acid is dropt into a solution of nitrate of lead, crystals of formate of lead in needles are immediately deposited. Liebig has found that formic acid may be obtained, con'^aining only 1 atom water, by decomposing dry formate of lead by sul- phuretted hydrogen. When of this strength it is much more cor- rosive than concentrated sulphuric acid. The smallest drop applied to the skin occasions a sensation, like that produced by red hot iron. A sore is produced, which is long in healing. This hydrate crystallizes at 32° and boils at 212° like water. The common acid, which is a bihydrate, crystallizes at 5° and boils at 226 ^°.f SECTION IV. — OF MELLITIC ACID. This acid has been described in the Chemistry of Inorganic Bodies (vol. ii. p. G2). In that description an analysis of mellate of alumina by Wiihler is given. From this analysis it was inferred, that the atomic weight of mellitic acid is 6*5, and from the charac- ters of the acid it was presumed that it contained no hydrogen ; but was a compound of C"* O^. But the subject has been lately investigated by Liebig and Pelouze.t They consider mellitic acid as a compound of 4 atoms carbon .... 3 4 atoms oxygen .... 4 1 atom hydrogen . . . . 0*125 7-125 They consider the atom of water which may be extricated from the acid, not as existing in it as water, but as constituting an integrant part of the acid. They found that 100 parts of mellate of silver dried for 24 hours over sulphuric acid in vacuOy were composed of Mellitic acid, . 33-08 or 7-167 Oxide of silver . 66*92 or 14.5 This raises the atomic weight to 7*167. The salt thus dried loses no more weight though kept at 212°. But at a higher temperature, water is again disengaged. After this, if it be heated up to 356° it loses its white colour, and assumes that of chloride of silver. When the heat is still farther raised, a slight detonation is observed, and there remains what is probably a chemi- cal compound of carbon and silver, but no water whatever is extri- ' Ann. de Cliiin. ct de Phys. lii. 107 + Jour, de Phurmacio, xxi. 381 . X Ann. der Pharm. xix. '252. 20 VOLATILE ACIDS. m cated. The mellate of silver, dried in vacuo, contains mellitic acid, composed of C* H O'*, and an atom of oxide of silver : that dried in a higher temperature, is C* O^ Ar. Liebig and Pelouze are of opinion, that the atom of hydrogen in the acid, combines with the oxygen of the base, and thus reduces the silver to the metallic state. SECT. v. — OF SUCCINIC ACID. This has been described in the Chemistry of Inorganic Bodies^ (vol. ii. p. 89). It has been recently analyzed by MM. Liebig and Wbhler,* and by M. Felix Darcet.f The results obtained agree with the old analysis by Berzelius, given in the Chemistry of Inorganic Bodies, (ii. 91). But a number of important facts re- specting this acid has been ascertained by M. F. Darcet, which it will be proper to state here. Succinic acid may be obtained in three states: — 1. Combined with an atom of water. 2. Combined with half an atom of water. 3. Anhydrous. In the first state it constitutes the crystallized acid of the shops, supposing that acid pure. It is soluble in water, and much more soluble in hot than in cold water. So that it is easily crystallized by cooling the hot solution. It is less soluble in alcohol, and scarcely at all in ether. It melts at 3.56° and boils at 455**. To determine the atomic weight of succinic acid, Darcet analyzed anhydrous succinate of silver, and obtained Succinic acid . . . 30-39 or 6*33 Oxide of silver . . . 69*61 or 14*5 100-00 According to this analysis the atomic weight of succinic acid is 6*33, approaching as nearly to 6*25, which I had shown to be its true atomic weight, as could be expected. M. DarcetJ analyzed the crystallized succinic acid by means of oxide of copper, and obtained, as the ultimate constituents. Carbon 40*22 or 4 atoras=3 or per cent. 40*67 Hydrogen 5*48 or 3 atoms--0-375 — ■— 5*09 Oxygen 54*30 or 4 atoms=4 — — 54*24 100 7*375 100 These numbers correspond with an atomic weight of 7*375, while dry succinic acid has an atomic weight of 6*25, and is composed of C^ H^ O'. It is obvious that the crystals consist of an atom of succinic acid combined with an atom of water ; or it is C* H" O' + H 0.§ When crystallized succinic acid is kept for a long time in a re- tort at a temperature of 266° or between that and 284'', it under- * Poggendorfs Annalen, xviii. 163. + Ann. de Chim. et de Phys. Iviii. 282. X Journ. fur Pract. ch. iii. '212, or Jour, dc Pharmacic, xx. 656. § This new analysis corresponds sufficiently with the old one by Berzelius. o n t r( ci J T fi- re ar so liz th( foi coi on Pe ACETIC ACin. 21 57 )9 24 }, while )sed of ktom of In a re- under- ^ I J goes a remarkable change. By degrees there are deposited, in the neck of the retort, a great number of beautiful whito needles, while at the same time a little water is disengaged. These needles con- sist of succinic acid deprived of half its water, while the portion in the retort remains unaltered. It seems to have been this dihy- drous succinic acid that was analyzed by Liebig and Wiihler. M. Darcet subjected it to analysis and obtained Carbon 43'46 or 4 atoms=3 or per cent. 44*03 Hydrogen 4-87 or 2^ atoras=0-3125 -— — 4-59 Oxygen 51-67 or 3J atoms=3-5 — — 51-38 6.8125 100 Liebig and Wohler obtained Carbon • • 44-12 Hydrogen • • 4-83 Oxygen • • 51-05 ■lUS. 100-00 . These numbers correspond, as nearly as could be expected, with the supposition, that the needles consist of an atom of succinic acid united to half an atom of water. Anhydrous succinic acid may be obtained by distilling a mixture of dry phosphoric acid with crystallized succinic acid. The best method of proceeding is, to fuse the succinic acid in a retort, and then add the phosphoric acid and distil slowly. We obtain in the receiver a crystalline mass, white, and consisting of anhydrous suc- cinic acid. It yielded when analyzed, C.irbon 47-34 or 4 atoras=3 or per cent. 48 Hydrogen 4-20 or 2 atoms=0-25 — — 4 Oxygen 48-46 or 3 atoms=3 — — 48 100-00 6-25 100 Thus we see that the atomic weight of anhydrous succinic acid is 6-25 Anhydrous succinic acid, though left exposed to the air, does not recover the water which it has lost. It melts, when heated to 393°, and boils at the tempera'.ure of 482°. It is less soluble in water than hydrous succinic acid ; but more soluble in alcohol and ether. If we dissolve it in water and crystal- lize, we shall find that the crystals recover the atom of water which the acid had lost. The salts formed by it are the same as those formed with crystallized succinic acid. SECTION VI. — OF ACETIC ACID. The only addition which it seems necessary to make to the ac- count of acetic acid, given in the 2d volume of the Chemistry of In- organic Bodies, is the following, for which we are indebted to M. Pelouze. Liquid acetic acid, composed of 1 atom pure acid and 1 atom t ifi ii il ! 22 VOLATILE ACIDS. Wcater, which ha? a specific gravity of 1*06296, does not redden litmus paper. It may he kept in contact with dry carbonate of lime, as Ion"- as we please, or even boiled over it without disengaging a sino-le bubble of carbonic acid gas, or combining with the lime; yet it dissolves quicklime instantly. It decomposes carbonate of potash, soda, lead, zinc, strontian, barytes, and magnesia, disengag- ing their carbonic acid ; but its action on the last three carbonates is very slow. The same acid, when diluted with water, acts with great' energy on all these carbonates. When the crystallizable acetic acid is mixed with several times its volume of alcohol, it loses all its action upon every one of these carbonates. If we dissolve acetate of potash in alcohol, and pass a current of carbonic acid gas through the solution, carbonate of potash is .)rc- cipitated and ace c ether formed. But carbonic acid does not throw down lime from the acetate dissolved in water.* SECTION VII. OF LACTIC ACID. The account of lactic acid, in the Chemistry of Inorganic Bodies, (ii. 55), left some uncertainty about its nature, which has been removed by the subsequent experiments of MM. Jules Gay-Lussac and Pelouze.f These chemists obtained pure lactic acid by the following process. A large quantity of beet-root juice was placed in a stove, and kept at a temperature between 77" and 86°. In a few days, fermentation commenced, and hydrogen and carburetted hydrogen gases were disengaged in abundance. When this fermentation (which con- tinued about two months) had subsided, the liquid was evaporated to the consistence of a syrup. Crystals of mannite made their appearance in it, and it contained a quantity of sugar similar to that from the sugar cane. The syrup being digested with alcohol, the lactic acid was dissolved in that liquid, while various substances, not subjected to examination, were left undissolved. Water was mixed with the alcoholic solution, and the alcohol distilled off, which occasioned another precipitation. The lactic acid in the aqueous solution, was saturated with carbonate of zinc. This saturation occasioned a still more abundant precipitation than had taken place befon. The liquid being sufficiently concentrated, the lactate of zinc crystallized. It was collected and heated in water, containing animal charcoal previously digested in muriatic acid. The boiling solution being filtered and concentrated, lactate of zinc separated in crystals perfectly white. They were washed in boiling alcohol, in which liquid they are insoluble. The lactate of zinc thus purified, was dissolved in water, and the oxide of zinc precipi- tated by barytes water. The lactate of barytes thus formed, was decomposed, l»y adding just the quantity of sulphuric acid requisite to saturate the barytes contained in it. The \u\uu\ was filtered, and * Pclouze, Ann. tie Chiin. rt de Pliys. 1. 314, t Ann. U' Cliitn. ct dc Phys. lii. 410. LACTIC ACID. 28 prccipi- ed, was equisite red, and the lactic acid concentrated by evaporation, in the vacuum of an air- pump. Finally, the lactic acid thus obtained in a state of dryness, was agitated with sulphuric ether, which dissolved it, leaving behind a few particles of a flocky matter. Lactic acid obtained in this way, and as concentrated as possible, is a colourless liquid, of a syrupy consistence, and having a specific gravity (at the temperature of 69") of 1*2 15. It has no smell. Its taste is exceedingly sour. Indeed, in this respect it may be com- pared to the most powerful of the vegetable acids. It attracts mois- ture when exposed to the air. Water and alcohol dissolve it in all proportions, ether likewise dissolves it, but in smaller quantity. When boiled with concentrated nitric acid, it is converted into oxalic acid. Two drops of lactic acid, added to 1543 grains of boiling milk, produce its immediate coagulation. But a considerably greater quantity of the acid does not alter cold milk. It possesses also the property of coagulating albumen when added in small quantity. It dissolves the phosphate of lime of bones with rapidity. When boiled with a solution of acetate of potash, it disengages the acetic acid. When dropt into a concentrated solution of acetate of magnesia, it occasions in a few minutes a white granular precipitate of lactate of magnesia, and the liquid assumes a strong smell of vinegar. It throws down in like manner a precipitate of lactate of zinc, when added to a concentrated solution of acetate of zinc. But lactate of silver is decomposed by acetate of potash, acetate of silver being deposited in abundance. Lactic acid occasions no muddiness in lime, strontian, or barytes water. When lactic acid in its most concentrated state is heated gradually, and cautiously, it becomes more fluid, assumes a darker colour, and gives (besides inflammable gas, vinegar, and a residue of charcoal) a great quantity of white solid matter, having at once an acid and bitter taste. When this substance is exposed to pressure between folds of bloiting paper, it is freed from an odorous substance which accompanies it. Thus purified, it dissolves abundantly in boiling alcohol, whence it is deposited, as the solution cools in very white rhomboidal tables. These crystals have no smell, and their taste is incomparably less sour, than that of the lactic acid in a liquid state, owing doubtless to their little solubility in water. These crystals melt when heated to 125°. They boil at the temperature of 482°, giviug out white and irritating vapours. When these vapours are brought in contact with a cold body, they form crystals similar to those from which they were produced. These vapours are inflammable, and burn with a pure blue flame. The crystals may be sublimed, without leaving any residue, and give no indica- tion of the presence of water. Its tendency to assume a crystalline form is very remarkable. These crystals dissolve very slowly in water ; but the solution ,f i V; 'fit 34 VOLATILE ACIUS. once formed cannot be made to yield crystals. It thickens to a syrup, and presents exactly the appearance and properties of the liquid lactic acid, from which they were originally obtained. MM. Jules Gay-Lussac and relouze, subjected the syrupy acid to analysis, and obtained from an average of two trials. Carbon 40*30 or 6 atoms =4'5 or per cent. 40 Hydrogen 6'96 or 6 atoms =:0'75 — — 6*66 Oxygen 52*74 or 6 atoms =6 — — 53*34 100*00 11*25 100 The crystals being analyzed in the same way, gave, as the average of three trials, Carbon 49*1 or 6 atoms =4*5 or percent. 50 • Hydrogen 5*6 or 4 atoms =0*5 — — 5*5 Oxygen 45*3 or 4 atoms =4 — — 44*5 100-0 9 100*0 MM. Jules Gay-Lussac and Pelouze analyzed lactates of zinc, copper, and silver, and the mean of four analyses gives the atomic weight of lactic acid 10*33. Now, 6 atoms carbon . . =4*5 5 atoms hydrogen . . = 0*625 5 atoms oxygen . . =5*0 10*1^5 But the analysis of lactic acid gave only 6 atoms carbon, 4 atoms hydrogen, and 4 atoms oxygen. Hence it would appear, that the lactates examined, after being dried at 248°, still retain an atom of water. The true atomic weight of anhydrous lactic acid is doubtless 9, and it differs from acetic acid, by containing 2 addi- tional atoms of carbon + 1 atom hydrogen + 1 atom oxygen. This analysis of lactic acid, has been confirmed by MM. Liebig and E. Mitscherlich,* they found that lactate of zinc was composed of Lactic acid' 54*93 or 10.316 =1 atom Oxide of zinc 27*29 or 5*125 =1 atom Water 17*78 or 3*375 =3 atoms <^ V( oj w ol e: tl F 100*00 The salt had been kept at 266° till it ceased to lose water. Their analysis of the acid in the salt, gave the formula 6 carbon, =4*5 or per cent. 44*44 ' 5 hydrogen, =0*625 — — 6*17 5 oxygen, ==5 — — 49*39 j 10*125 100 If we admit that the acid, after exposure to a heat of 266°, stil m bi lil 'f ! * Aniialen dcr Pharm. vii. 47. LACTIC ACID. 25 I retained an atom of water, the result obtained by Liebig and Mitscherlich, will coincide with that of J. Gay-Lussac and Pelouze. Liebig has shown that the acid in sauer kraut is the lactic* We are indebted to J. Gay-Lussac and Pelouze for an exami- nation of several of the lactates, with an account of which we shall terminate this section. L Lactate of lime. This salt is white and very soluble in boiling water, from which it is deposited, on cooling, in very short white needles, radiating from a common centre. It is very soluble in hot alcohol. When heated it undergoes the watery fusion, and after- wards the igneous fusion, and is at last decomposed like other salts containing a combustible acid, ^ts constituents are 1 atom lactic acid ..... 9 1 atom lime ...... 3*5 6 atoms water 6*75 rbon, 4 ar, that atom acid is addi- 19-25 2. Lactate of magnesia is easily obtained by double decomposition. It forms brilliant white crystals, which effloresce slightly in the air, and require 30 times their weight of water to dissolve them. They are composed of 1 atom lactic acid 9 ' 1 atom magnesia 2-5 4 atoms water 4-5 16 3. Lactate of alumina crystallizes, though with difficulty. It is very soluble in water. The same description applies to the lactates of potash, soda and ammonia. 4. Lactate of proloxide of iron. Lactic acid attacks iron filings with energy, while hydrogen gas is evolved. The lactated protoxide of iron precipitates in four-sided needles, little soluble in water and exceedingly white. In a dry state it does not alter by exposure to the air ; but when held ir solution by water, the iron is speedily peroxidized. Its constituents are 1 atom lactic acid 9 1 atom protoxide of iron . . . 4*5 6 atoms water 6*75 ", stil 20*25 5. Lactate of peroxide of iron is brown and deliquescent. 6. Lactate cf manganese crystallizes readily. The shape, accord- ing to M. Braconnot, is a flat rectangular prism terminated by a bihedral summit. 7. Lactate of cobalt has a red colour, and crystallizes in grains little soluble in water. It is composed of * Ann. dcrPharm. xziii. 113. I 1 I 86 VOLATILE ACIDS. i I 1 atom lactic acid 1 atom oxide of cobalt 3.5 atoms water 4-25 3-9375 17'1875 When the water is driven oft' it assumes an exceedingly beautiful colour. 8. Lactate of nickel has a grass-green colour, and is more soluble than lactate of cobalt. Its crystals were so confused that the shape could not be determined. 9. Lactate of zinc is white, and little soluble in cold, but more solu- ble in boiling water. It crystallizes in four-sided prisms terminated by oblique summits. It is insoluble in alcohol, and is composed of 1 atom lactic acid • . . . 9 1 atom oxide of zinc . . . . 5* 1 25 4 atoms water ..... 4*5 18-625 10. Lactate of copper has a fine blue colour and crystallizes readily in four-sided prisms. It effloresces when exposed to the air. It is insoluble in alcohol. It may be formed by leaving lactic acid in contact with suboxide of copper. Lactate is formed and copper separates. This salt is composed of 1 atom lactic acid .... 9 1 atom oxide of copper ... 5 3 atoms water 3-375 17-375 11. Lactate of mercury is very soluble in water, and on that ac- count is not easily crystallized. 12. Lactate of silver crystallizes in fine but long needles. It is very white, very soluble in water, and easily altered by light. 13. Lactate of chromium does not crystallize.* SECTION VIII. — SUBERIC ACID. In the history of this acid, in the Chemistry of Inorganic Bodies (ii. 117), the constituents of it, according to the analysis of it by Dr R. Brandes, are given as follows : — Carbon 37-2536 Hydrogen 15*9856 Oxygen 46-7608 100-0000 M. Bussy had analysed it in 1822, and had obtained Carbon 56*29 Hydrogen 6*89 Oxygen 36*82 * Ann. de Chim. ei dc Phys. Hi. 4 10. 100-OOt t Jour, de Pharmacic, viii. 110. NAPUTHALIC ACID. «7 The great difference between tlus result and that of lirandes, in- duced liiin to repeat his analysis. The acid employed was carefully prepared, and seems to have been ultimately sublimed, in order to free it completely from all foreign matter. It was white, quite soluble in water, and had a weak acid taste. It did not melt till it ./aS heated to 255°. If it be dried at 212**, it loses no weight when fused. When the heat is raised above 255", suberic acid distils over like the^^ acids. If the acid was not quite pure, but had a yellow colour, the first portion distilled was a dirty rose red, the middle portions were pure, and the last portion impure and yellow. When the acid was pure, what came over was pure, and on cooling, concreted into a crystalline mass, having a slightly empyreumatic smell ; and there remained in the retort a small quantity of charry matter. It was soluble in water and alcohol, and precipitated from alcohol by water. M. Bussy found suberate of lead rendered anhydrous, to be com- posed of Suberic acid . . . 207'6 or 9*905 Oxide of lead . . 292-4 or 14 500-0 According to this analysis, the atomic weight of suberic acid is 9-905. The sublimed acid being analysed by means of oxide o" copper, the mean of five analyses gave Carbon 55-20 or 8 atoms =6 or per cent. 55-18 Hydrogen 8-03 or 7 atoms = 0-875 — — 8-04 Oxygen 36-77 or 4 atoms =4 — . _ 36-78 100 10-875 100 But when 100 parts of sublimed suberic acid are heated with oxide of lead, they lose, at an average of three experiments, 9*133 of their weight, showing that water is still present. It is obvious from this, that the sublimed acid contains 1 atom of water. The anhydrous acid, of course, is a compound of 8 atoms carbon . . 6 6 atomi hydrogen . . 0-75 3 'dtovrs oxygen . . 3 110. So that its true atomic weight is 9-75.* 9-75 SECTION IX. — OF NAVHTHALIC ACID. This acid was discovered and described by M. Laurent, about the beginning of 1836.t The mode of preparing it is the following : • Bussy, PogrgendorPs Annalen, xxix. 151, and Jour, de Pharmacie, xix. 423. These experiments of Bussy were confirmed by the subsequent researches of Brandes. See Ann. der Pharmacie, ix. 295. f Ann. de Chim. ct de Pliys. Ixi. 1 13. 28 VOLATILE ACIDS. Ill Introduce into a retort muriate of chloronaphtlialese,* and pour on it four or live times its woiglit of common nitric acid, and raise the temperature to the boilinj^ point. The action is very slow, about 300 grains of the matter requiring a whole day to convert it into naphthalic acid. Evaporate the solution to dryness to get rid of the greatest part of the nitric acid. We obtain a mass confusedly crystal ized, and having a yellow colour. Pour into the retort a larn^e quantity of water, and boil till the greater part of this residue is dissolved. A little brown matter remains, which is sometimes mixed with a small portion of muriate of chloronaphthalese unaltered. Filter the solution while boiling hot. On cooling, pearly plates are deposited, which commonly unite in concentric round groups. De- cant off the mother water, and evaporate again. On cooling we get a new crop of crystals. And in this way we proceed till we exhaust the liquid. Naphthalic acid thus obtained has a yellowish red colour. To purify it we must dissolve it anew, and crystallize it a second time, or it may be sublimed. For sublimation, it may be put into a porcelain capsule, covered with a glass capsule containing cold water. When the lower capsule is slightly heated the acid sublimes, and crystallizes on the glass capsule in the form of beautiful white needles, having a great deal of lustre. The acid tiius purified is white, brilliant, and in long feathery crystals. They are, in fact, oblique four-sided prisms. Naphtha- lic acid has a great deal of resemblance to benzoic. When heated it melts at 22 P; on cooling, it concretes into a tibrous mass. When the heat is still farther raised, the acid is volatilized without decom- position in white fumes, which have a certain degree of pungency. These fumes readily catch fire and burn with a strong flame, giving out much soot. Naphthalic acid is unaltered in the air. When kept in corked phials it is slightly volatilized, crystals being deposited on the sides of the phial at the end of some months. It has no smell. Its taste is weak, and by no means disagreeable. While dry it has no effect on litmus paper ; but it reddens it if moistened. In cold water it is scarcely soluble ; but pretty soluble in boiling water. Alcohol and ether dissolve it easily. Chlorine has no action on it. Muriatic acid, nitric acid, and sulphuric acid, dissolve it at a boiling heat, but do not alter it. M. Laurent analyzed it by means of oxide of copper, and ob- tained Carbon 64-70 or 10 atoms = 7"5 or per cent. 63*83 Hydrogen 2-38 or 2 atoms = 0-25 — — 2-13 . Oxygen 32-92 or 4 atoms = 4-0 — — 34-04 (i 100 11-75 100 * For the nature of this body, see a subsequent Chapter, iu which naphthaline and its compounds are described. "^.-^ NAPHTIIALIC ACID. Lnd ob- bthalino i I S9 The acid, in the state in whicli it was analyzed, was anhydrous. But when it is crystalll/ed from a solution in boiling water, it is combined with an atom of water. The alkaline nuphthalatcs are very soluble in water, and less soluble in alcohol. The naphthalates with bases of the alkaline earths, are little soluble. Those of lead and silver are insoluble ; yet the water employed to wash them becomes muddy when mixed with muriatic or sulphuric acid. The g I'ater number of them have the singular property, when heated, of becominjj elonjrated to a great extent under the form of a black glass, while, at the same time, a peculiar jrystalline matter is disengaged from them. The soluble naphthalates, when in solu- tion, may be recognised by mixing them with muriatic or nitric acid, a white precipitate falling crystallized in needles. It is naph- thalic acid. If they are insoluble, we heat them in a tube with some drops of concentrated sulphuric acid : naphthalic acid sublimes in needles. Naphthalic acid is very similar in appearance to benzoic acid, but it may be easily distinguished by combining it with am- monia, with which it forms a very characteristic salt. 1. Naphthalate of ammonia. When we leave to spontaneous evaporation a solution of naphthalate of ammonia the base is disen- gaged by little and little, and we obtain an acid salt remarkable for the beauty of its crystallizations. The crystals are right oblique prisms, with a cleavage parallel to the rhombic bases. We may, by means of a knife, detach plates as thin as those of sulphate of lime. Sometimes the crystals are hexagonal plates, sometimes in octa- hedrons, obviously derived from the prism. It is not altered by exposure to the air, and strongly reddens litmus paper. When heated in a tube it melts, and then is decom- posed without leaving any residue ; being converted into water, am- monia, and a new acid, which suL^imes in white plates. Its composition, as determined by the analysis of Laurent, is as follows :t- 1^ atom naphthalic acid . . 15*66 1 atom ammonia . . . 2' 125 1^ atom water 1-5 19-285 No doubt, if it could be crystallized without loss of ammonia, the composition would be I atom naphthalic acid . . 11 "75 1 atom ammonia . . . 2*125 2 atoms water . . . . 2*25 16-125 Probably it might be obtained in this state by crystallizing in vacuo over sulphuric acid. 2. Naphthalate of potash. This salt is exceedingly soluble in water. To obtain it in crystals, we must evaporate the aqueous 80 VOI.ATILR ACIDS. w golution to (Iryrcss, and dissolvo the rcalduo in other. Wo obtain the salt in scales, having a poarly histro. When dried, it iu com- posed of 1 atom naphthalic acid . . . 11 '75 1 atom potueh .... 6 17-75 3. Naphthalate of soda. It is also very sohihlo. When h.'ft to spontaneous cry^^illization tho surface becoiiK's covered with a crystalline crust, which prevents the rest of the liquid from evapo- rating. When dissolved in boiling alcohol it crystallizes in plates as the solution cools. 4. Naphthalate of harytes. Obtained by mixing concentrated solutions of naphthalate of ammonia and chloride o, barimn. It pre- cipitates in white scales, soluble in water. 5. Naphthalate of lime. Similar to naphthalate of barytos, and obtained by the same kind of process. 6. Naphthalate of magnesia. Sulphate of magnesia is not pre- cipitated by naphthalate of anmionia. 7. Naphthalate of zinc. This salt is little soluble in water. As we evaporate its solution it falls down in a crystalline powder. When heated it is decomposed, giving out an oil which crystallizes on cooling. It may bo obtained by dissolving carbonate of zinc in naphthalic acid. 8. Naphthalate of lead. When boiling solutions of naphthalate of ammonia very dilute, and a salt of lead are mixed together, naph- thalate of lead falls down in silver white plates. It constitutes a neutral salt. 9. Naphthalate of silver. Obtained by mixing boiling solutions of naphthalate of ammonia and nitrate of silver. The salt precipi- tates in white shining plates. When heated in a porcelain dish, it decomposes with such rapidity, that M. Laurent was not able to determine its composition exactly. Naphthalamide. This substance may be obtained by heating naphthalate of ammonia in a retort. Water and ammonia are diseutiaged, and naphthalamide sublimes, while nothing remains in the rett)rt. Naphthalamide is colourless, inodorous and insipid. When heated, it enters into fusion, and on cuoling soliditicjs into a fibrous mass. When heated more strongly, it boils, emitting vapours which con- dense under the form of very light crystalline plates. It is almost insoluble in cold water. Boiling water dissolves a little, but as the liquid cools the naphthalamide is deposited in very fine silky needles. Weak and dilute acids have no action on it. Chlorine does not attack it. Concentrated sulphuric acid dissolves it with the assist- ance of heat. If we dilute the solution with water and allow it to cool, crystals of hydrated naphthalic acid are deposited. A con- sKUAric Acin. 31 as ilky not list- tto Bon- ccntrnted alcoholic Holutlon of potash, when hnllod upon it, disonjja^'ea uuiinonia. It" wo now wattirato tiio pota.sh with Bulphuric acid and cvajioratc to dryncHS, naphthalic acid Hubliuics. M. Laiiront subjected naj)lithalan>ido to an analysis by means of oxide of copper. He obtained ('arbon (H'C)^) ov 33 atoms = 24*7r> or per cent. ()4'39 Ilydrojren 310 or 9] atoms = 1-1H75 -- — 3-09 Azote H'90 or 2 atoms = 3-50 — — 9'U) Oxygen 23-35 or 9 atoms = 9-00 — — 23-42 100-00 ,38-4375 100 M. Laurent considers it as isomeric with binaphthalate of am- monia. Hut supposing wo wore to reduce the atoms to one-half, they would not tally with binaphthalate of ammonia, which is Q-20 in QH ^ fp Az ; whilo naplitlialamide would be C'«* H'i O** + PP Az. NnphCalic ether. If we boil in a retort, a nixture of alcohol, muriatic acid, and naphthalic acid, we obtain at the end of the distillation an oily matter which remains in the retort. It is heavier than water, and is considered by M. Laurent, who, however, has never examined it, as naphthalic ether. SECT. X. — OF SEUACIC ACID. Though this acid had been noticed by the chemists of the last century, and though Crell had given various processes for preparing it ;* yet its characters do not seem to have been determined till Thenard published an accouni; of if in tbo year 1799.t Berzelius, in his Traite de Chimie, considf^. it as the same with benzoic acid; but the analysis of it in 1834, ;)y Dumas and Peligot, showed that it had no resemblance whatever io that acid in its composition.:^ It is easily obtained by distillimg a quantity of tallow, and agitat- ing the product in boiling w iter, which dissolves the acetic acid. The water thus impregnated is mixed with acetate of lead, which throws down a precipitate of sebate of lead. It is washed, dried, and treated with dilute sulphuric acid, which forms an insoluble com- pound with the oxid(! of lead. The sebacic acid, thus set at liberty dissolves very well, if we boil it in water, and it crystallizes vvlun the liquid cools. By two or three successive crystallizations it is freed from any sulphuric acid with which it may be at first mixed, and brought into a state of purity. Sebacic acid thus obtained crystallizes in white needles, having a pearly lustre. It has no smell, and is almost uestitute of taste, though it reddens litmus paper. It meits when heated, and may be volatilized like benzoic acid, and • Jour, de Phys. xviii. 100 and 383— xix. 384. t Ann. de Chim. xxxix. 193. t Ann. de Chim. et de Phys. Ivii. 332. *. Ifl m 32 VOLATILE ACIDS. is much more soluble in hot than in cold water. It is very soluble in alcohol. When a strong acid is poured into a concentrated sebate, a precipitate of sebacic acid immediately appears. Dumas and Peligot subjected it to two several analyses by means of oxide of copper. The analyses do not agree very well with each other. But they seem to consider the last as the most to be de- pended on. Taking it as correct, the constituents of sebacic acid are Carbon 59*59 or 10 atoms=7*5 or per cent. 59'40 Hydrogen 9-04 or 9 atoms=M25 — — 8-91 Oxygen 31-37 or 4 atoms=4 -- — 31-69 100-00 12-625 10000 To determine the atomic weight of sebacic acid they dissolved in water a quantity of neutral sebate of ammonia, and mixed the solu- tion wi;l> nitrate of silver. The sebate of silver which precipitated was well washed and dried at the temperature of 248° in vacuo. In two successive analyses they obtained Sebacic acid .... 106-7 or 11-77 Oxide of silver . . . 131-3 or 14-5 Sebacic acid . . . . 91-2 or 11-93 Oxide of silver . . . 110-8 or 14-5 The mean of these analyses gives us 11-85 for the atomic weight of sebacic acid. But the atomic weight deduced from the analysis of the acid is 12-625 greater than results from the constitution of sebate of silver. It is obvious from this, that the sebacic acid, as it was analyzed by Dumas and Peligot, was a hydrate containing one atom of water. If we subtract this atom, we have for the composi- tion of anhydrous sebacic acid, 10 atoms carbon . • . . . =7.5 8 atoms hydrogen . . . . =1 3 atoms oxygen . . . . . =3 11 5 giving us an atomic weight of 11-5, which does not deviate too far from that deduced from the sebate of silver. Now this constitution is quite different from that of benzoic acid which is composed of 14 atoms carbon .... =10-5 . , 5 atoms hydrogen . . . . = 0-625 3 atoms oxygen . . . . = 3-0 "t ' 14125 And has an atomic weight of 14-125. Sebacic acid occasions precipitates when dropt into acetate or nitrate of lead, nitrate of silver, acetate or nitrate of mercury. It saturates the alkalies and forms with them soluble salts. The sebate of potash does not absorb moisture from the air, it has little taste, and when sulphuric, nitric, or nuu-iatic acid is added to it, the solution becomes muddy, and sebacic acid is deposited. CAMPHORIC ACID. 33 air, it julded tod. It produces no precipitates when dropt into lime, barytes, or strontian water. SECT XI. — OF CAMPHORIC ACID. This acid has been described in the Chemistry of Inorganic Bodies, (vol. ii. p. 114). But since that time an important set of ex- periments on its composition, and that of camphor, has been made by M. Liebig.* When camphor is treated with concentrated nitric acid^ it melts, as is well known, into a yellowish liquid. If we prolong the diges- tion this yellow liquid disappears entirely, and the acid on cooling deposits a great number of white opaque crystals, which, when boiled with water, communicate to its vapour the odour of camphor. These crystals constitute the camphoric acid of Bouillon La Grange, which form, with all the bases, salts which are insoluble or nearly so. They arc in reality a chemical combination of camphoric acid and camphor, and may be formed directly by dissolving camphor in camphoric acid melted in a gentle heat. If we treat these crystals a second time with concentrated nitric acid, we obtain more trans- parent crystals. These crystals constitute camphoric acid, and form the same kind of salts which Brandes described. An account of them will be found in the Chapter on Salts, in the second volume of the Chemistry of Inorganic Bodies. To determine the atomic weight of this acid, Liebig combined it with oxide of lead and tried experimentally how much sulphate of lead a given weight of the anhydrous camphorate of lead was capable of furnishing. The result was that the salt is composed of Camphoric acid .... 957 or 14 Oxide of lead .... 957 or 14 1914 This gives 14 for the atomic weight of camphoric acid. Liebig subjected camphoric acid to an analysis by means of oxide of copper, and obtained 61-4098 or 12 atoms=:9 or per cent. 64-28 6-8070 or 8 atoms=l — — 7-14 . Carbon Hydrogen Oxygen 31-7832 or ^4 atoms=:4 — — 28-58 100 14 100-00 But these numbers differ so mucli from the results obtained, that the analysis cannot be considered as satisfactory. This induced M. Liebig to heat a portion of his camphoric acid a third time with nitric acid, and tO' continue the action till all smell of camphor dis- appeared, when the camphoric acid was boiled with water. Cam- ' phoratc of lead prepared with this new acid was composed of Camphoric acid . . . 545 or 13-625 Oxide of lead . . . 560 or 14 1105 * Ann, de Chim. et He Pliys. xlvii. 95. D A 34 VOLATILE ACIDS. h According to this new analysis the atomic weight is only 13-625 instead of 14, as by the first analysis. The camphorate of lead being analyzed by means of oxide of copper, he obtained Carbon 56* 167 or 10 atoms=7'5 or per cent. 55'82 Hydrogen 6-981 or 7J atoms=0-9375 — — 6-97 Oxygen 36-852 or 5 atoms=5 — — 37-21 100 13-4375 100-00 This would make the atomic weight 13*4375, which differs but little from that obtained from the analysis of camphorate of lead. When camphor is treated with nitric acid, no effervescence or disengagement of carbonic acid is observed. From this it would seem, that camphor constitutes the base of camphoric acid, or that camphoric acid is a compound of camphor and oxygen. To de- termine this point, M. Liebig analyzed camphor, and obtained Carbon . . . 81-763 Hydrogen . . . 9-702 Oxygen . . . 8-535 100-000 These numbers lead to the conclusion that camphor is a compound of 81-763 or 12 atoms carbon =9 or per cent. 80-89 9-702 or 9 atoms hydrogen = 1-125 — — 10-12 8-535 or 1 atom oxygen =1- — — 8-99 11-125 00-00 100 or 6 (C^ Wi) + O. _ Now, if we express the composition of camphoric acid by the formula 5 (C H** ) ■+- O", it will result from camphor, if each of the atoms of camphor combine with 5 atoms of oxygen. So that 5 atoms of camphor will produce 6 atoms of camphoric acid. This explanation, for which we are indebted to Liebig, seems a little strained. It would be simpler to consider camphor as composed of Q\o j^7j o, and to admit that it is converted into camphoric acid, merely by combining with 4 atoms? of oxygen. This would make the constitution of camphor Carbon • Hydrogen Oxygen 79-55 9-93 10-52 100-00 Now, if we consider the great diflSculty of analyzing camphor with accuracy, perhaps the deviation of these numbers from those ob- tained l)y Liebig, is not greater than might have been expected. M. Laurent has made a set of experiments still more lately on the component parts of camphoric acid. To convert the camphor into camphoric acid, he distilled it 30 times in succession with nitric acid. formula of the that 5 This a little losed of fie acid, Id make lor with lose ob- Ited. on the [or into nitric VALERIANIC ACID. 86 From the analysis of camphorate of silver, he deduced the atomic weight of the acid to be 1 1'7. The anhydrous acid he found com- posed of 10 atoms carbon = 7*5 or per cent. 65*93 7 atoms hydrogen = 0'S85 — — 7*69 3 atoms oxygen =3- — — 26*38 11*385 100*00 The hydrous acid of 10 atoms carbon =: 7*5 or per cent. 60 8 atoms hydrogen =1* — — 8 4 atoms oxygen =4* — — 32 12*5* 100 Still more lately M. Mallagutti has repeated this analysis with crystallized acid, and obtained Carbon .... 59*50 Hydrogen .... 7.98 Oxygen .... 33*52 100*00t These numbers correspond with the following atomic constitu- tions : — 10 - ' • carbon = 7*5 or per cent. 60 8 aii'T! hydrogen =1 — — 8 4 atoms oxygen =4 — — 32 12*5 100 If we consider this acid as containing an atom of water, of course, the anhydrous acid will have the constitution assigned above by M. Laurent. The coincidence in the results of these two chemists, seems to leave no doubt about the true constitution of camphoric acid. SECTION XII. — OF VALERIANIC ACID. Some years ago, M. Pentz accidentally discovered an acid in the water expressed from the Valeriana officinalis. From some experi- ments which he made on this acid, he considered it to be the acetic. M. Grote made some additional experiments on this acid, but did not determine whether it was merely acetic acid, or an acid of a different nature. In 1833, M. J. Trommsdorf published the result of his experiments upon it, described its properties, and showed that it differed in its characters from all the acids hitherto observed, and that it was entitled to rank as a peculiar acid. He gave it the name of valerianic acid, from the plant from which alone it can be procured.^ * Ann. de Chim. et de Phys. Ixiii. 207. f Ibid. p. 151. X Ann. de Chim. et de Phys. iiv. 208 ; or Annalcn der Pharmacie, vi. 76. 36 VOiA'vUE Acros. I I When the roots of the Valeriana ojff nnalis are distilled with water, there pass over into the receiver, water and an oil ; both of which contain valerianic acid. Saturate the water with carbonate of potash, and treat the oil with caustic potash ley. Concentrate the aqueous portion, add a sufficient quantity of sulphuric acid to saturate the potash, and distil to dryness. We obtain in the re- ceiver an aqueous solution of valerianic acid, with a quantity of the same acid swimming upon it in the state of an oily hydrate. Trommsdorf gives us also another process, namely, to distil the acid oil with carbonate of magnesia. The oil passes over into the receiver, while val- iinate of magnesia remains in the retort. This salt is decomposed oy adding the requisite quantity of sulphuric acid to combine with the magnesia. Valerianic acid obtained by either of these processes, is in the state of a hydrate. We cannot deprive it of its water by distilling it off chloride of calcium, because this salt alters the nature of tlie acid, and seems to communicate muriatic acid. But it may be partially deprived of 'to water by simple distilla- tion, taking care to keep the receiver cooi, and stopping the process when the drops which pass over cease to be milky. Valerianic acid thus obtained, is a colourless, limpid, oleaginous liquid. It has u peculiar odour, having, however, considerable analogy with that of the root of valerian and the essential oil from the same plant. But it is more disagreeable, and cannot be re- moved either by animal charcoal, or any other process ; but is diminished when the valerianic acid is combined with a ba?e. The taste of the acid is very strong, very sour, and very disagreeable, and the impression of it remains long in the mouth. When very dilute, it leaves on the palate an impression of sweetness. Its specific gravity at 50° is 0*944, that of water being unity. It remains liquid though cooled Jown to — ()°. When heated in a pla- tinum spoon, it readily catches fire, and burns with a strong flame, leaving no residue. It stains paper like an oil, but the stain may be completely removed by heat, wif-hout injuring the paper. It boils at the temperature of 270" under the pressure of the atmo- sphere ; but it begins to evaporate at a much lower heat. This acid reddens litmus paper as powerfully as any of the mineral acids ; but if the paper be left exposed to the atmosphere, its blue colour is very soon restored. When as well freed from water as possible, this acid requires 30 times its weight of water to dissolve it com- pletely. Alcohol dissolves it in every ])roportion. A solution of equal parts of alcohol and valerianic acid becomes muddy when water is added ; but it becomes again transparent if we add water in great excess ami then agitate. It is insoluble in oil of turpentine. If we agitate such a mixture it become* milky, and the two Tn^uids gradually separate from each other. The same thing ha])pens wlien we agitate valerianic acid with olive oil. It dissolves rapidly and abundantly in concentrated acetic acid, of 1 a IX o: I n a a li^ ty. It 1 a pla- flarae, 111 may er. It atmo- This acids ; lour is ssible, com- ion of water kixture li each acid Icid, of VALERIANIC ACID. 87 the specific gravity 1*07. Fumino; sulphuric acid makes it yellow when added cold. If heat be applied, the valerianic acid is charred, and sulphurous acid disengaged. Nitric acid scarcely acts upon it, even when the two liquids are distilled together. Valerianic acid dissolves iodine, but when water is added, a por- tion of the iodine is thrown down. Camphor dissolves in it also, slowly indeed, but abundantly. The solution is thick and colourless, and may be distilled over without alteration. When it is agitated with thirty times its weight of water the camphor is separated. To determine the atomic weight of this acid, valerianate of barytes was formed by (digesting the acid over carbonate of barytes in powder. The solution was crystallized in vacuo over sulphuric acid. 1'he crystals were afterwards raised to the temperature of 266° and exposed to a current of dry air, till their water of crystal- lization was dissipated. This anhydrous salt was analyzed by ignlii m, in a platinum crucible, which converted it into carbonate of bar ,'tes. The mean of two analyses made in this way, gave Valerianic acid . . . 1*55 or ll'5j Barytes . . . 1-28 or 9*5 according to this analysis, the atomic weight is 11 '5. This atomic weight was confirmed by an analysis of valerianate of sil> or, which was found composed of Valerianic acid . . . 11 5 14 Oxide of silver . . . 14*5 M. Ettling, assistant to M. Liebig, analyzed tae valerianic acid in these two salts, by heating determinate proportions of valerianate of barytes and of silver with oxide of copper. The results obtained gave the constituents as follows : — Salt of Barytes. Salt ot Silver. Mean. Carbon 64-97 63-65 64-310 Hydrogen 9*63 9-68 9-655 Oxygen 25*40 26-67 26-035 100-00 ! 100.00 100-000 From these we deduce the atomic constituents as follows : — 10 atoms carbon =7*5 or per cent. 64-52 9 atoms hydrogen = 1-125 — — Q-67 3 atoms oxygen =3-0 — — 25-81 11-625 TOO-OO From this it appears, that the atomic weight of valerianic acid is 1 1-625, and that it differs from sebacic acid, by containing one atom more of hydrogen. Valerianic acid in an isolated state, after having been rendered as anhydrous as possible, still retains an atom of water, being composed, according to M. Ettling's analysis, of 10 atoms carbon . . =7*5 10 atoms hydrogen . . =1-25 4 atoms oxygen . . =4 12-75 « ! 88 VOLATILE ACIDS. These numbers obviously difFer from the preceding, by an atom of water, which raises the atomic weight from 1 1*625 to 12-75- The valerianates, so far as they have been examined, possess the following properties. They have a peculiar smell, and a sweet taste, leaving a sharp impression in the mouth. Some of them remain unaltered in the air, while others effloresce and some even deliquesce. Some may be obtained >n regular crystals, while others only give amorphous crusts. Most of them have a slightly soapy feci. Some are soluble in water, while others are only imperfectly so. The greater num- ber are soluble in alcohol. They are all decoi >sed by heat. At the beginning of the action, valerianic acid is oft' disengaged unaltered. If to a concentrated solution of a valerial.^,te, we add sulphuric, nitric, arsenic, phos- phoric, muriatic, tartaric, malic, succinic, or acetic acid, valerianic acid immediately separates in an oleaginous state. Benzoic acid has no action on the valerianates. But valerianic acid decomposes the benzoates and carbonates.* The following are the valerianates that have been particularly examined by Tromrasdorf :t 1. Valerianate of soda. When a mixture of valerianic acid, water, and carbonate of soda is ^eated, carbonic acid gas is disengaged, and the valerianate c ? soda formed. The neutral solution is colour- less, and does not crystallize when concentrated. By cautious eva- poration we obtain a white mass, tallowy in appearance, and having a sweet taste. It is very soluble in absolute alcohol, absorbs mois- ture, and deliquesces in the air, and is very soluble in water. When heated to 266", it becomes very soft : at 284°, it melts into a colour- less transparent liquid without allowing any of the acid to escape. On cooling, it concretes into a snow-white mass. Its constituents, as determined by Trommsdorf, are Valerianic acid . . 11*27 Soda .... 4 15*27 2. Valerianate of potash. It may be obtained as the former salt. It is neutral, does not crystallize, has a very sweet taste, deliquesces in a moist atmosphere, and is very soluble in water and alcohol. It melts at 284°, without decomposition ; but when raised to a higher temperature, decomposition takes places. Its analysis gave Valerianic acid . . 11*62 Potash ... 6 17*62 3. Valerianate of ammonia. This salt may be formed, by adding an .xcess of carbonate of ammonia to the acid mixed with water. If it contain an excess of ammonia, it crystallizes in needles, having Trorumsilorf, Ami. de Chiin. ct . salt, lesces W. It [ding later. \y'mg VALERIANIC ACID. 39 a sweet taste, leaving an impression of valerian. When these crystals are exposed to the air, they lose a portion of their base, and become acid. Trommsdorf could not obtain this salt in a state fit for analysis. 4. Valerianate of lime. This salt may be obtained by the same process as the preceding. The neutral solution is colourless, and yields, when concentrated, small prismatic crystals, united in the form of stars. When dried, the salt forms a brittle white mass. Its taste is very sweet. The crystals effloresce in a warm atmo- sphere, but remain unaltered in moist air. They dissolve madily in water and spirits, but scarcely in absolute alcohol. When heated to 284° it becomes soft, and loses some of its acid. In a higher temperature it melt , but becomes quite black, giving out a thick vapour, wh' 1 burns with a light-coloured flame. Its constituents, as determined by Trommsdorf, are Valerianic acid Lime .... 11 -So 3-5 14-03 5. Valerianate ofharytes. Prepared as the former sslts. Its taste is sweet, with an impression of valerian oil. It crystallizes in prisms, dissolves readily in water, and is not altered by exposure to the air. By the analysis of Ettling, it is composed oi Valerianic acid Barytes 6. Valerianate of strontian. It crystallizes in long four-sided tables, which effloresce in the air. It is pretty soluble in water, and dissolves also in alcohol, and the solution burns with a carmine-red flame. The taste is sweet, and somewhat sharp. It is composed, according to Trommsdorf, of Valerianic acid . . . 11*6 Strontian .... 6'5 18-1 7. Valerianate of glucina. Formed by dissolving carbonate of glucina in a mixture of water, and valerianic acid. The solution does not crystallize. When dried, it forms an opaque gummy-look- ing matter. The taste is very sweet, leaving an impression of as- tringency. It is not altered by exposure to the air. It is com- posed of Valerianic acid . . . 11*73 Glucina . ... 3*25 8. Valerianate ofzirconia. Zirconia may be dissolved in valeri- anic acid by gentle boiling, but only in small quantity, and the solu- tion has an acid reaction, yet it has a sweetish taste. By careful evaporation, the greatest part of the excess of valerianic acid is dis- engaged. No crystals arc obtained, but a white dry mass, which 40 VOLATILE ACIDS. HI is not complotely soluble in water. Zirconia seems to have a very weak affinity tor valerianic acid. 9. Valerianate of alumina. When alumina, which has not been exposed to a red heat, is ])laced in contact with valerianic acid, combination speedily takes place. When hot water is added to the compound, no solution follows ; but flocks swim in the liquid, which soon fall to the bottom. On cooling they concrete, and resemble tallow which has been melted and allowed to cool. Water dissolves merely a trace of this substance ; nor is it soluble in valerianic acid. It I3 very soft, has a sweetish taste, and is insoluble in alcohol. Ac- cording to Trommsdorf, it is composed of Valerianic acid . . . 1 2*49 Alumina . . . . 2*25 It is obvious that it contained an excess of acid. 10. Valerianate of magnesia. A neutral salt which shoots into fine transparent prisms, they effloresce in dry air but remain unaltered in moist air. When the solution is evaporated no crystals are ob- tained but merely an amorphous mass. The taste is very sweet. Slightly soluble in alcohol. The salt is easily decomposed by heat. Trommsdorf found it composed of Valerianic acid . . . II "21 Magnesia . . . . • 2*5 11. Valerianate of Lead. Metallic lead dissolves very slowly in valerianic acid, and carbonate of lead dissolves only in a boiling heat. The salt is soluble in boiling water. When digested with more oxide of lead, a subsalt is formed, which falls to the bottom. The neutral salt has a very sweet and astringent taste. When slowly evaporated it deposits white plates. When rapidly concentrated it forms a tough mass, which absorbs some moisture from the atmo- sphere, and is very soluble in water. It is composed, according to Trommsdorfs analysis, of Valerianic acid . . . 11*63 Oxide of lead . . . 14 12. Valerianate of silver. Ettling formed this salt by mixing together solutions of nitrate of silver and valerianate of barytes, tak- ing care to have a small excess of the latter salt. It fiills down in white cheesy flocks, which after some days assume a crystalline tex- ture. Its colour, when dried, is greyish white. It was dried at 266°, and was found a compound of Valerianic acid . . . 1 1 •;') Oxide of silver . . . 14-5 26-0* 13. Valerianate of cobalt. Carbonate of cobalt dissolves in valer- ianic acid when assisted by heat. The solution has a rose-red col- our, and does not crystallize. When dried, the salt is a violet red, transparent, foliated mass. When dissolved in as small a quantity of water as possible, so as to form a syrup, and left in a cold place, * Ann. (Icr Pharmacic, vi. 186. VALERIANIC ACID. 41 very iv m it shoots into violet-red prismatic crystals. It is very soluble in water and alcohol, has a sweet and astringent taste, and is not altered by exposure to the air. 14. Valerianate of copper. Valerianic acid gradually dissolves copper, assuming a dark-green colour. When water is added to the saturated solution, the salt swims on the surface like a green oil. When the liquid is evaporated, it yields green ])rismatic crystals of neutral valerianate of copper. The salt dissolves readily in boiling water and alcohol. It is not altered by exposure to the air. 15. Valerianate a/ nickel. Valerianic acid does not act on metallic nickel ; but it rapidly dissolves the carbonate when assisted by heat, assuming the appearance of a thick green oil. Boiling water dis- solves a little of it ; but the addition of alcohol occasions a complete solution of a light-green colour. By evaporation we obtain a light- green mass very difficultly solubii in water. 16. Valerianate of iron. Valerianic acid dissolves iron slowly, and gradually assumes a dark brownish-red coloiu*. When water is added the salt separates under the "orm of a brown oil. The water is scarcely coloured, but caustic potash throws down a red precipi- tate showing that the iron it peroxidized. Newly precipitated hy- drated peroxide of iron is slightly soluble in valerianic acid. We may form a neutral valerianate of iron by mixing together solutions of perchloride of iron and valerianate of soda. The light brown pre- cipitate becomes darker when dried, and is very little soluble in water. It is doubtless a compound of Valerianic acid . . . 11*5 Peroxide of iron ... 5 ps, tak- )wn in le tex- lied at valer- col- red, Intity llace. 16-5 17. Valerianate of mercury. Mercury is not attacked by valer- ianic acid. But when red oxide of mercury is added by little and little to the hot acid, a combination takes place, having the appear- ance of a red transparent oil, which on cooling concretes into a mass of the consistency of ointment. If more oxide be added than the acid is capable of dissolving, the compound has a brownish-red colour. Cold water dissolves little of this salt, but boiling water dissolves the most of it, and from the hot filtered solution crystals of valerianate of mercury shoot, in soft white needles grouped in stars. When the liquid from which the crystals were obtained is evapo- rated to dryness, a red insoluble matter remains, which is readily dissolved by valerianic acid when assisted by heat. When solutions of corrosive sublimate and valerianate of soda are mixed, neutral valerianate of mercury separates in soft white crystals, doubtless composed of Valerianic acid . . . li'5 Oxide of mercury . . . 13*5 25 18. Valerianate of zinc. Carbonate of zinc dissolves readily in m 42 VOLATILE ACTUS. valerianic arid when assisted by heat. When the solution is evapor- ated small shining plates are deposited resembling crystals of boracic acid. The taste is scarcely sweet but rather harsh. The salt dis- solves easily in water and alcohol, and is not altered by exposure to the air. At 284" it melts into a syrup without losing any acid. It is doubtless coin])oscd of Valerianic acid ... 11*5 ' Oxide of zinc . . . 5-125 manganese 16-625 19. Valerianate of manganese. The carbonate of dissolves readily in valerianic acid when assisted by heat. The solution yields crystals in rhombic tables, they have a fatty feel, a strong lustre, and are readily soluble in water. This salt ia doubt- less composed of Valerianic acid . . . 11-5 4-5 Oxide of manganese 16- SECTION XIII. — OF BENZOIC ACID. Benzoic acid, as it occurs in commerce, is usually contaminated with some resinous and oily matter. M. Righini has pointed out an economical method of purifying it. Dissolve the benzoic acid, to be purified in four or five times its weight of sulphuric acid pre- viously diluted with six times its weignt of water. When the solu- tion is boiling, add a very small quantity of pure animal charcoal, filter, ;i lid allow the liquid to cool. The benzoic acid is deposited in crystals. If these crystals are not in long beautiful needles, and if they still retain any smell, the process is to be repeated. Collect the crystals on a filter, wash them with cold water to remove the sulphuric acid, and then allow them to dry in the shade. The sul- phuric acid dissolves the resin and the oil with which the benzoic acid was contaminated, and thus leaves it in a state of purity.* Benzoic acid, when pure, has no smell. It melts when heated to 248°, and boils at 473**. But it sublimes readily in a current of air when gently heated. It gives out vapours, even at the ordinary temperature of the atmosphere. When sublimed, it assumes the form of long flat prismatic needles, having a beautiful satin lustre. The specific gravity of its vapour is about 4-27.t The crystals of benzoic acid were analyzed by MM. Wohler and Liebig, and found composed of Carbon 68*04 or 14 atoms = 10-5 or per cent. 68-85 Hydrogen 5'02 or Oxygen 26-94 or 6 atoms = 0-75 4 atoms = 4 loot 15-25 4-91 26-24 100-00 » Ann. de Chini. et de Phys. Ivi. 443. f Mitsehcrlich and Dumas. t Ann. de Chim. et de Phys, li. 282. / qua anc obtJ mo}i Th[ rest wei^ and! Pen tityl steel distf CINNAMONIC ACID. 43 t But when anhydrous benzoatc of silver was analyzed, it was found composed of Benzoic acid , 49*4() or 14*19 Oxide of silver . 50*54 or 14*5 100-00 The acid in benzoate of silver being subjected to an ultimate ana- lysis with oxide of copper, yielded Carbon 73*30 or 14 atoms = 10*5 or per cent. 74*34 Hydrogen 4*5(i or 5 atoms = 0*625 — — 4*42 Oxygen 22*14 or 3 atoms = 3*0 — —21*24 14*125 100 Thus it appears, that the atomic weight of benzoic acid is 14*125, and that the crystals consist of 1 atom of the acid united with 1 atom water. SECT. XIV. — OF CINNAMONIC ACID. This name has been given by Dumas and Peligot to a substance which occasionally appears in old oil of cinnamon, in large reddish- yellow crystals, and which has been noticed by various chemists, and confounded with benzoic or succinic acid, or with camphor. Cinnamon is the inner bark of the branches of the Laurns cinna- momum, a tree which grows in Ceylon, and in various other parts of the East Indies. Though known to the ancients, and used by them in their religious services, they seem to have been ignorant of the country whence it was imported, as both Herodotus and Pliny mention Africa as its place of nativity. The celebrated Benjamin Robins sent a specimen of the cinnamon tree to Sir William Watson, who gave an account of it in the Philosophical Transactions for 1751.* Of late years, much of the cinnamon of commerce comes from China, and is known by the name of Cassia. It is the produce of another species of tree, the laurus cassia. When cinnamon is distilled in the usual way, it yields a small quantity of a volatile oil, to which the bark is indebted for its taste and smell. Two varieties of oil of cinnamon occur in commerce, one obtained from the cinnamon of Ceylon, the bark of the laurus cinna- momum ; the other from cassia, the bark of the laurus cassia. The latter of these has a reddish-brown colour, a disagreeable smell resembling that of bugs, and sells at about thirty shillings the pound weight. The oil of cinnamon from Ceylon, has an agreeable smell, and sells at a much higher price. As this oil never occurs pure in commerce, MM. Dumas and Peligot, who undertook to examine its properties, prepared a quan- tity of it from Chinese cassia. They reduced the bark to powder, steeped it for twelve hours in water saturated with salt, and then distilled it over the naked fire. A milky water came over, which * Vol. xlvii. 301. I I 44 VOLATIKR ACID8. |i \ > "1 1 * ^'' _ — griulmiUy depositod its oil. This oil hoiiig distilled oil' cliloridi* of calcium was c^onsidi-rcd as pure. Oil of ciiinninoii n>s(!inl)l('s camphor strony^ly, in tlio way that concontratcd nitric acid acts upon it. It concrot(!s almost imme- diately, and forms with it a true crystalline salt, in which the oil of cinnamon acts the part of a hase. This comhination takes place imperfectly when the comiium oil of commerce is used, but the pure oil, when mixed with nitric acid, crystallizes directly. Oil of cinnamon combines with muriatic acid j^as ; but it assumes a greenish colour, indicating some alteration in its nature, which does not take place when it is combined with nitric acid. Itcombi'ics with ammonia, and forms a crystallized product which is not altered by exposure to the ntinosphere. Thus it has the curious property of combining both with acids and bases, and forming detin- ite componiuls with both. Oxygen gas is rapidly absorbed bv oil of cinnamon, especially when moist, and an acid is formed to which Dumas anu Peligot have given the name of cinnatnonic acid. We shall give an urcount of the properties of this acid after we have made a few observations on oil of cinnamon, which obviously constitutes its base. When oil of cinnamon is subjected to the action of hot nitric acid the smell of bitter almonds becomes perceptible, and when the acid ceases to act on the oil we find a great (piantity of benzoic; acid in the residue. When this oil is boiled with hypochlorite of lime a great quantity of benzoic acid is formed, or rather of benzoate of lime. When we heat it with an aqueous solution of potash, it does not appear to undergo any alteration. But if we heat it with hydrate of potash, a great quantity of pure hydrogen gas is driven off and cinnamate of ])otash is formed. When a current of chlorine is passed through the oil, a liquid chloride is at first formed, which appears to correspond with chloride of benzoyl ; but if we heat the oil and cause it to absorb as much chlorine as it will take up, we obtain a crystallized substance ap- proaching chloral in its constitution.* From the preceding account of the properties of oil of cinnamon, as determined by Dumas and Peligot, it is obvious that it is very analagous to oil of bitter almonds. They consider it a:^ a compound of hydrogen and the base of cinnamonic acid, to which they have given the name of cinnamoyl. The oil they distinguisli by the name of hydret of ciimamoyl. But while the hydrct of benzoyl forms only combinations in which the radical of benzoic acid always appears unaltered, the hydret of cinnamoyl often undergoes a molecular alteration, which destroys its proper radical, which is replaced by the radical of benzoic acid. This shows that the ratiical of cinna- monic acid is much less stable than the radical of benzoic acid ; a circumstance which renders its investigation considerably more difficult. * Ann. lie Chiin, et lie Pliys. Ivii. 308. ( INNAMONIC ACM). 4ft 1 1 lilt |naiTion, is very iipound sy have le name forms H)])ears ilecular ced by cinna- [cid ; a more Dumas and Poli^ot suhjoetod oil of ciiiiiumon to an idtimatu analysis by moans of oxide of copjH'r, and obtained CJarbon HOC or IH atoiiis= KJ'f) or per cent. 81"80 IIvdro;j;en (••4 or !) atoms= I ••2') — — it'll Okygen i;j'0 or 2 atoms= 2-0 — — 12-()3 100 l(>-«)25 100-00 M. Blanchet has also analyzed oil of cinnamon.* lie obtained Carl)on 80*3 or IH atoiiis= Kl'S or per cent. 80'(i0 Ilydro^jen 7*7 or 10 atouis=- l'2r) — — 7*47 Oxvijen 12-0 or 2 atoms= 2*0 — — ll-!)3 100 1()-7H 100-00 If it be a hydret of cinnamoyl it is obvious that eiimamoyl must be C'** li" O'^ or C'« H" O'^ Cinnamonic acid frequently occurs in old oil of eiimamon in large yellow crystals. These crystals are prisms, they dissolve in b iling water, which, on cooling, deposits the pure acid in colourless pearly plates. As the acid is but little soluble even in hot water, it is ne- cessary to digest the impure crystals in successive portions of boil'jig water as long as the liciuid continues, on cooling, to deposit the })early plates. This acid was subjected to an ultimate analysis, by Dunuis and Pcligot ; by means of oxide of copper, they obtained Carbon 72-44 or 18 atoms = 13-5 or per cent. 72-97 Hydrogen b'lW) or 8 atoms =1 — — 5-41 Oxygen 21-<)0 or 4 atoms =4 — — 21-62 100 18-5 100-00 Two different analyses of cinnamate of silver were made, the mean of which gave its Constituents Cinnamonic acid . 54*9 or 17*65 Oxide of silver . 45-1 or 14*5 100-0 It is obvious that the cinnamonic acid analyzed, contained an atom of water, while the acid in the cinnamate of silver was anhydrous. To verify this, Dumas and Pcligot analyzed the cinnamonu ..• id in the cinnamate of silver, and obtained Carbon 76-41 or 18 atoms = 13-5 or per cent. 77-71 Hydrogen 5-32 or 7 atoms = 0-875 — — 5-03 Oxygen 18-27 or 3 atoms = 3-0 — — 17'26 17-375 100-00 It is obvious from these analyses, that cinnamonic acid has an atomic weight of 17-375, and that its constitution is expressed by the formula, (>"* IP O^. The crystals after being dried in vacuo, still retain an atom of water. * PoggenJorfs Annalcn, xxxiii. 58. 46 VOLATILE ACIDS. Let US now compare the constitution of oil of cinnamon and cin- namonic acid. Oil of cinnamon is . . . C'^ H^ 0» Cinnaraonic acid . . . C* H^ O' We see that the oil is converted into cinnamonic acid, by depriving it of an atom of hydrogen, and adding an atom of oxygen. The base of cinnamonic acid or cinnamoyl is C* H^ O'*. Oil of cinnamon is a hydret of that base, or C'^ H'' O'^ + H, and cinna- monic acid C'8 H^ 02+0. Cinnaraonic acid is colourless. It melts at 248** and boils at 559". At that temperature it may be completely distilled over without leaving any residue. When slowly heated, it sublimes in brilliant plates, very similar to the crystals of benzoic acid. Its vapour has a strong odour, and excites coughing. It is very little soluble in cold water, but hot water is a better solvent ; and this solution, on cooling, concretes into a gelatinous crystalline mass, having a pearly lustre. Alcohol is a good solvent of this acid, and it is precipitated from its solution by water. It combines with bases, and forms salts, which, in general, have a striking resemblance to the corresponding benzoates ; but hitherto the properties of these salts have not been much examined. Nitric acid decomposes cinnamonic acid ; red vapours are disen- gaged, and oil of bitter almonds formed, and finally benzoic acid is deposited.* Dumas and Peligoi have also examined the action of chlorine, nitric acid, muriatic acid, and ammonia, upon oil of cinnamon; and have shown that the compounds formed may be thus represented : Chloride of cinnamoyl . C'* H' 0» + Chi Nitrate of cinnamoyl 1 atom cinnamoyl C* H'' O' 1 atom nitric acid O' Az 1 atom water H O Qu H7 02 + Az 0« + H O Muriate of oil of cinnamon C'^ H» O^ + H Chi Ammoniated oil of cinnamon C** H® 0^ + H' Az SECTION XV. OF HIPPURIC ACID. Rouelle was the first person who discovered the existence of ben- zoic acid in the urine of the horse.f Fourcroy and Vauquelin an- nounced, that this benzoic acid existed in the urine of the horse in the state of benzoate of soda.J Scheele, and after him Fourcroy and Vauquelin, found that the same acid existed in the urine of infants. This discovery was confirmed by the subsequent experi- ments of Proust and Thenard. In 1834, M. Liebig§ resumed the examination of the urine of the horse, and satisfied himself by nu- * Dumas and Pcligot, Ann. de Chim. et de Phys. Ivii. 311. t Jour, de Medicine, 1777. ijl Mem. de 1' Institute, ii. 431. ^Annalen der Pharmacie, xii. 20. HIPPURIC ACID. 47 merous experiments, that the acid contained in it was not the ben- zoic, as hitherto supposed; but another easily convertible into benzoic acid, and which he distinguished by the name of hippuric acid* To obtain it, he concentrated the urine of the horse, and mixed it with muriatic acid in slight excess. On setting the mixture aside, yellowish-brown crystals were deposited, having a peculiar and dis- agreeable smell. When these crystals were dissolved in water, and the solution boiled with animal charcoal, the liquid, after filtration, was colourless : and the concentrated solution, on cooling, deposited large semitransparent brittle crystals, which constituted pure hip- puric acid. When hippuric acid is heated it melts, undergoes decomposition, and becomes black ; while, at the same time, benzoic acid sublimes, and a very distinct odour of bitter almonds is observed, and a great quantity of porous charcoal remains. When mixed and heated with four times- its weight of hydrate of lime, it allows a great deal of ammonia to be disengaged, while, at the same time, a volatile oil passes over into the receiver. Sulphuric acid dissolves hippuric acid with facility, without black- ening, at the temperature of 248°, and water throws it down again unaltered. But when the sulphuric acid solution is heated above 248°, i ulphurous acid and benzoic acid are disengaged. It dissolves with equal facility in nitric acid ; but by a boiling heat, it is entirely converted into benzoic acid, though scarcely any nitrous or carbonic acid is evolved. It dissolves in hot muriatic acid, and when the solution cools the hippuric acid crystallizes, possessed of all its pro- perties : an excess of chlorine does not attack it ; but when boiled with a great excess of hypochlorite of lime, it is converted into ben- zoic acid. Liebig subjected anhydrous hippuric acid to an analysis by means of oxide of copper. He found hippurate of silver composed of Hippuric acid . . 61-09 or 22*79 Oxide of silver . . 38-91 or 14-5 100-00 This would make the atomic weight of hippuric acid 22*79. But Dumas and Peligot, who repeated the analysis with great care, ob- tained Hippuric acid . . 59*9 or 21-65 Oxide of silver . . 40-1 or 14-5 nu- lOO'Of This makes the atomic weight only 21 -65. The same chemists subjected hippuric acid to an analysis with oxide of copper. • Form i**a(, a horse, and iv^n, urine, f Ann. de Chim. et de Phys. Ivii, 329. 48 VOLATILE ACIDS. Ir The following table shows the constituents of this acid according to the two analyses. Liebig. 60'7392 4-9588 7-8518 26-4502 Carbon Hydrogen Azote Oxygen Dumas and Peligot. 60-68 5-21 7-70 26-41 loot ley indicate for the atomic 3-5 or per cent. 60-34 1-125 — 5-02 1-75 7-82 6-00 — 26-82 100-0000* These numbers very nearly agree. T constitution of hippuric acid, 18 atoms carbon = 9 atoms hydrogen = 1 atom azote = 6 atoms oxygen = 22-375 Now, 22-375 is nearly the mean of the atomic weights deduced by Liebig and Dumas and Peligot from their respective analyses. Dumas and Peligot are of opinion, that hippuric acid, as analyzed both by themselves and by Liebig, contained an atom of water. If that supposition be well founded, its constitution, supposing anhydrous, will be 18 atoms carbon . . = 8 atoms hydrogen . . — 1 atom azote . . = 5 atoms oxygen . . = 21-25 and its atomic weight 21-25. We can now see how hippuric acid is converted into benzoic acid, Hippuric acid is . C* H* Az O^ Benzoic acid is . C* H^ O^ It Remain . . . C^ H^ Az O^ H^ Az is an atom of ammonia. There remains C^ O^. If we add 2 atoms of water and 2 atoms of oxygen, we get 2 atoms of for- mic acid C^ H^ O^. Thus it appears that hippuric acid is capable, with the addition of water and oxygen, of being converted into 1 atom benzoic acid, 1 atom ammonia, and 2 atoms formic acid. Now when Dumas and Peligot tn ted hippuric acid with hypochlorite of lime, saturated the liquids and heated them with nitrate of silver, or a salt of mercury, metallic silver or mercury was always precipi- tated, a phenomenon which characterizes formic acid. Hippuric acid readily dissolves the greater number of the bases. Its soluble salts precipitate the peroxide of iron with the colour of * Poirgcndorrs Annalon, xxxii, 573. f Aim. de Uhim ct do I'liys. Ivii. 3"2G. HIPPURIC ACID. 49 ling jmic dby yzed . If ig it acid, I we for- able, ito 1 Now orito ver, icipi- ases. ir of rust. They precipitate the nitrates of silver, and suboxide of silver, in white heavy flocks. 1. Hippurate of ammonia. The neutral salt crystallizes with difficulty, but the supersalt readily. When the neutral salt is eva- porated it gives out ammonia. When evaporated to dryness, it melts and assumes a red colour. This residue is soluble in hot water, and the liquid on cooling deposits red crystals, which have the characters of hippuric acid. 2. Hippiirates of potash, soda, and magnesia. These salts are very soluble and difficultly crystallizable. 3. Hippurate of barytes. When we boil hippuric acid over car- bonate of barytes, we obtain a liquid which reacts as an alkali, and which, when evaporated, assumes the form of a jelly. When allowed to cool, it constitutes conical masses, having a white colour like por- celain. This white matter, after having been dried in vacuo, melts, when greatly heated, without diminishing in weight, and forms a clear liquid, which, on cooling, is converted iftto a transparent glass. If we dissolve this subsalt in water, and add dilute acetic acid till it becomes sensibly acid, we obtain by evaporation white ti'ansparent plates of neutral hippurate of barytes. 4. Hippurate of lime. This salt is prepared by heating the acid with carbonate of lime. It crystallizes on cooling in rhombic prisms, and by evaporation we obtain it in large shining plates. It dissolves in 18 times its weight of cold, and 6 times its weight of boiling water. Its taste is bitter and sharp. 5. Hippiirates of cobalt and nickel. The salts of cobalt and nickel are not precipitated by hippuric acid. The carbonate of cobalt dis- solves readily in that acid, and the concentrated solution deposits red needles, which contain water of crystallization. 6. Hippurate of lead. Oxide of lead when heated with water and hippuric acid is partly dissolved. Another portion of it forms a tough mass which remains at the bottom of the vessel, and is easily decomposed and blackened even under water. The portion dissolved constitutes a subsalt, which, by evaporation, forms a tough shining skin on the surface of the liquid. When sufficiently concentrated it constitutes a white mass. The neutral salt may be obtained by mixing together solutions of a salt of lead and a hippurate. On cooling, the salt is deposited in silky needles, which when dried become tender, and assume a pearly lustre. In a dry atmosphere they become opaque and white. This salt is soluble in between 5 and 6 times its weight in water. 7. Hippurate of copper. The carbonate or hydrous oxide of cop- per dissolves readily in hippuric acid. The salt crystallizes in blue needles so united as to constitute stars. At a high temperature these needles lose tlieir water of crystallization and become green. 8. Hippurate of silver. Obtained by mixing concentric solutions of hippurate of potash and nitrate of silver. It is deposited in white flocks. When the solutions are dilute, the salt is slowly de- posited in crystalline grains. Its constituents are E iMf r f m 50 VOLATILE ACIDS. 1 atom hippuric acid I atom oxide of silver 21-25 14-5 35-75* PVom the experiments of Dr. C. G. Lehman of Leipsig, it would appear that hippuric acid is gradually formed in diabetic urine after it has been voided.f SECTION XVII. — OF ESCULIC ACID. This acid was discovered by M. Fromy ; but the only account of it hitherto publisiied, is. in the 5tli v^olume (p. 296) of Dumas' Traile fie Chimie appliquce mix Arts. M. Fremy, by treating horse chc';5tnu'3 (the fruit oi Esculus hip- pocastaniim) with alcohol of O-83'l, and evaporating the liquid, obtained a light yellow viscid matter, which was deposited in flocks. It had a very striking resemblance to the substance extracted by M. Bussy, from the Sapoaaria of EgyptJ which he called saponin. When saponin, or the substance from the horse chestnut is digested in acids cold, no change is produced. But when the temperature is raised to 195° or to 212° a white matter instantly precipitates, which is esciilic acid. Esculic acid is insoluble in water, soluble in alcohol, and is deposited from that solution in crystalline grains. It dissolves in hot nitric acid, nitrous acid being disengaged, and is converted into a yellow resin. This resin dissolves in potash, but when precipi- tated from the solution by an acid it still retains azote as a constituent. We do not know the atomic weight of this acid ; but it has been subjected to an ultimate analysis by means of oxide of copper. The constituents are Carbon 58-19 or 52 atoms = 39- or per cent 56'7 Hydrogen 8*27 or 46 atoms = 5-75 — — 8-3 Oxygen 33-54 or 24 atoms =24- — _ 35 68-75 100-0 These numbers given by M. Dumas, do not accord very well with the analysis; but it is not worth while to correct them till the atomic weight of esculic acid be determined. The esculates of potash, soda, and ammonia, are too soluble in water to crystallize. When concentrated sufficiently, they assume the form of a jelly. They are insoluble in alcohol of 0-817, and crystallize in pearly plates in alcoliol of 0'!)'28. All the other escu- lates are insoluble in water ; but they all dissolve, and some of them crystallize in weak alcohol. Esculic acid and saponin, have some resemblance to a substance found in sarsaparilla, which has been distinguished by the name of sarsnparillin. * Duni:is C'liiniii! a|)pliqiioG aiix Arts*, v. 2'20. t Jour. (!e Fliaiin. xxii. N2. % f> iijisop/iila stiuthium. ESCULIC ACID. M It may be worth while to make a few observations on the saponin, extracted by Bussy, from the gypsophila struthium* because it is very intimately related to, if not quite the same as, the saponin from the horse chestnut. To obtain it, M. Bussy digests the saponaria of Egypt in boiling alcohol of 0'834. After some minutes' boiling, the alcohol is filtered and left to cool. The saponin partly precipitates. It is collected on a cloth. And this treatment is repeated till the root is ex- hausted. Saponin thus obtained is white, incrystallizable and friable. It has an acrid and sharp taste, which remains long in the mouth. When in powder, it acts as a powerful sternutatory. It is soluble in water in all proportions. The solution is at first muddy, but it gradually acquires transparency, by being repeatedly filtered. It froths strongly when agitated, even when it contains only i^j^jyth of its weight of saponin. The same weight of it does not form a mucilage so thick as gum does. When the solution is evaporated, it leaves a shining varnish, easily detached from the vessel and reduced to powder. Alcohol of all strengths dissolves saponin ; the weak spirits in all proportions, while absolute alcohol dissolves only one-fifth of its weight of it. Ether does not act upon it. It burns in the air and emits an aromatic smell. When distilled it blackens, swells, and gives off an acid cnipyreumatic oil. Boiling acids, according to M. Fremy, convert it into esculic acid. Boiling nitric acid, according to M. Bussy, decomposes it, forming a yellow resin, mucic acid, and oxalic acid. Weak alkalies have no action on it while cold ; but boiling potash changes it into esculate of potash. Its constituents, according to the analysis of M. Bussy, are Carbon 51-3 or 2G atoms = 19-50 Hydrogen 7-4 or 23 atoms = 2-875 41-3 or 16 atoms = 16-0 Oxvffen 100-0 79-375 M. Bussy found the compound of saponin and oxide of lead, com- posed of Saponin . . . 72-8 or 37*47 Oxide of lead . . 27-2 or 14 100-0 tan CO lie of • Jour, lie Pharmacic, xix. 1. H fi2 FIXED ACIDS, CHVrTER II. OF F I X I D ACIDS. In the preceding Chapter an account has been given of those vegc- tabl ■ acids which may be volatilized by heat without decomposition. But by far the greatest number are deci^mposed when heat is applica ; and, in general, wl r-.i the req'iirite care is taken not to fany the heat too far, new acids are il rmed, possessing properties {[uitr- different from those by the decoii. position of which they have V)een obtained. Only eight of tliese fixed acids have been hithertc -..ib- jected to these experiments. Bui there cannot be any doubt that most, if not all, of the remaining rixed acids, as soon •v; they a e properly examined, will be found to })cbl similor Mi'oducts. The following table exhibits a view nf the (•o;;!position of the.^e eight .'.cids, with the names and constitution of the aci'ls obt'tined by theli' decomposition : — Acids. Composition. 1 MaiJc C* W 0* 2 Citric . Do. 3 Tartaric y HM> 4 Bnreniic Ox jJhydric I'D. 5 Mucic C" H*0' I 6 Meconic CJ H^O^ i 7 Gallic . C" H^O-' <' Kinic C'* H» 0« Derivative Acids C imposition. 1 Miiloie or Eqii setic C' H 0» 2 I'iir.siiiHleic or Fainaric ho. .'.. Pyrocitric , C5 ipo^ 4. Citrine , Do. 5 I'yrotartaric , C tFO» G Pynivic , C" H'H)^ Yields similar acids. 7 Paraniiicic . C/' 'FO^ 8 Pyroniueic . C" 11' 0' 9 Pyromecoiiic (JIO H < 09 10 Aletaiiieconic Q\2 HI Ol" 11 PyrofTiiUic . C" HM)' 12 J\l('ta}.'allic . CIS H3 U^ 13 Pvrokinic. I'he following table gives the composition of the remaining fixed vegetable acids, which have been hitherto investigated with toler- able av;- uracy :- 1 Ellagic . 2 Cahincic . C^ FP 0* C7i H« 0"'* Bicoloric . C^ H^i 0^ 3 Caffeic . C'2 HIT Qio Picrotoxic C'2 W 0' 4 Japonic 5 Mechloic C'2 H^ 0* 6 Catechuic €'■' IP 0^ 7 Amygdalic 8 Tannic C40 H2G 0^^ C'« IP 0'2 9 Rubinic CIS H« 0'» 10 Uhnic C/'o 11'^ O'" We shall give an account of all these acids in the following Sc< tions : — g fixed 1 toler- g Scc- MALIC ACID. 53 SECT I. — OF MALIC ACID. In the account of malic acid given in the Cliemisiry of Inorganic Bodies (ii. 70), two different analyses of it arc stated, one by Prout and another by Frommrerz. These two were utterly irreconcilable with each other. In consequence of which it was impossible to ''orae to any satisfactory conclusion respecting the constitution of this acid. The subject has been since taken up by Liebig,* who has shown that malic and citric acids are isomeric bodies. He obtained, as the result of a very careful analysis, for the constituents of malic acid, 41*02 or 4 atoms carbon =3 or per cent. 41*37 3*51 or 2 atoms hydrogen = 0*25 — — 3*45 55*47 or 4 atoms oxygen =4 — — 55*18 7*25 100*00 Liebig analyzed several of the malates, and showed that the a'.omic weight of malic acid is 7*25. 1. Malate of silver. When fused nitrate of silver and bimalate of ammonia are mixed together, we obtain a granular precipitate, hav- ing a brilliant white colour, but becoming yellow when dried. If we heat it after it has been dried, it swells up and undergoes decom- position, giving out an empyreumatic odour. Metallic silver re- mains in a state of purity, which adheres firmly to the porcelain crucible in which tlie experiment was made. Its constituents are Malic acid . . 33*41 or 7*33 Oxide of silver . . 6(J*59 or 14*5 100 If we admit that the malate of silver analyzed by Liebig contained 0*12 per cent, of water, then the quantity of malic acid, in 100 grains will be 33*29 grains, and the atomic weight will be exactly 7*25. When citrate of silver is heated it behaves quite differently from malate of silver. It requires to be heated with the utmost caution. At a certain temperature it makes a kind of explosion, and the whole crucible is filled with light spongy flocks of metallic silver. Both malate and citrate of silver dissolve readily in boiling water. When the solution of malate cools, small crystals are deposited, the liquid blackens, and lets fall metallic silver. The solution of citrate of sil er, in the same circumstances, deposits groups of con- centric needles having a yellowish-white colour, 2. Malate of zinc. The constituents of this salt are Malic acid . . . 63*08 or 8*75 Oxide of zinc . . 30*92 or 5*125 100 It is obvious that this salt contained either an excess of acid, or still retained water. The crystallized malate of zinc contains 3 atoms of water, which it loses when heated to between 212° and 248°. * Aniialcii der Phannucic, V. 141. S4 FIXED ACIDS. 3. Malate of magnesia. The crystals of this salt effloresco when exposed to the air. They are at first transparent, but become gradually opaque and white. Wl"^n dried at a temperature between 212° and 302°, it loses from 29*5 to 30 per cent, of water. But about one-fourth of its water still remains, which cannot be driven off even by the heat of a boiling solution of concentrated chloride of calcium. The crystals are composed of 1 atom malic acid . . . 7*25 1 atom magnesia . . . 2*5 5 atoms water . . . 5*()25 15-375 Heat drives off 4 of the 5 atoms ; but the other remains obstinately fixed at the greatest heat which can be applied without decompos- ing the acid. 4. Malate ofbarytes. It is very difficult to saturate malic acid by means of carborate of barytes. When the solution is evaporated, white crusts are deposited which have no appearance of crystalliza- tion. They are insoluble in water, whether hot or cold, but dis- solve rapidly when a little acid is added, and the liquid is not preci- pitated by ammonia. In this state it is anhydrous, and composed of 1 atom malic acid . . . 7 25 1 atom barytes . . . 9*5 16-73 From Liebig's analysis the dry salt seems still to retain 0*488 per cent, of water. After the neutral malate of barytes is deposited, if we continue to evaporate the solution, we obtain a supermalate of barytes, which is very soluble in water. Liebig did not succeed in his attemp<^s to form a submalate of barytes.* The crystals of malic acid are composed of 1 atom malic acid . . . 7-25 1 atom water . . . 1-125 8-375 They lose no weight at 248°, and can only be deprived of their water by combining them with a base. Malic acid melts at 181°. At 349° it is decomposed and resolved into water and two pyroacids, which are isomer ic.f SECTION II. — OF EQUISETIC OR MALEIC ACID. It was ascertained by Pelouze, that when malic acid is distilled at the temperature of 349°, it is resolved into water, and two pyro- acids, which are isomeric. These acids have been distinguished by the names oiequisetic ovmaleic, Sind/umaric or paramaleic acid.X Of these acids, the maleic is the most, and the paramaleic acid the least volatile. At 392°, much more maleic acid is formed than * Ann. de Chirn. et cie Phys. lii. 434. f Ibid. Ivi. 72. J Ibid. )f their t 181°. oacids, Tiistilled pyro- ruished acid.X iid the than EQUISETIC OH MALEIC ACID. 55 paramalcic. At 302°, scarcely any thing else is formed than water and paramalcic acid. Maleic acid crystallizes in ohlique four-sided prisms. It has no smell, but a very acid taste ; and it leaves a very disagreeable im- pression in the mouth. It is very soluble in water and alcohol. It melts at 2(JG°, and boils at 320°. At that temperature the crystals are decomposed into water, and anhydrous maleic acid. When kept in a temperature a little above its melting point, it is gradually transformed into crystals of paramaleic acid, and the heat may be raised to 392° without volatilizing or melting these crystals. When maleic acid is dissolved in water and left to spontaneous crystallizations, the crystals run up the sides of the vessel and make their way over it. Maleic acid is not precipitated by lime water. With barytes water a precipitate falls, which speedily assumes the form of small crystalline grains. The precipitate is re-dissolved, when an excess either of maleic acid or of barytes is added. No precipitate falls when this acid is dropt into solutions of chlo- ride of barium, chloride of calcium, sulphated peroxide of iron, or nitrate of silver. When concentrated solutions of maleate of potash, and chloride of calcium are mixed together, no precipitate falls ; but after an in- terval of some days, we find a deposition of crystalline needles of maleate of lime. Acetate of lead occasions a white precipitate when dropt into very dilute solutions of maleic acid. This precipitate speedily assumes the form of brilliant plates. When the solutions are concentrated, and the lead in excess, the whole assumes the appearance of a white tremulous mass like starch mucilage. Maleates of potash, soda, and ammonia, are very soluble. The last is incrystallizable. Maleate of barytes is obtained, by saturating a concentrated solu- tion of maleic acid with barytes water. In a few minutes the liquid assumes the form of a white jelly. When dried, it is in small crys- talline plates, and is composed of 1 atom maleic acid . . 6*125 1 atom barytes . . . 9*5 1 atom water . . . I'r25 l()-75* Maleate of silver is anhydrous, and slighly soluble in water. When heated to 300** or 302°, it is decomposed all at once, and changed into a dark-grey matter, having the metallic lustre, and into carbonic acid. At the same time, on the sides of the vessel, there appear yellow crystallizable drops, having a very sour taste. The residue washed in water, acidulated with muriatic acid till nothing more is dissolved, effervesces with nitric acid, and leaves black flocks of charcoal. It was a bicarburet of silver.f Rcgnaiilt, Jour, lie Pharin. xxiii. 31. f Rcgnatilt, ibid. V L \4 56 FIXED ACIDS. IM Mfileates of copper and iron are less aoluhle. Tlioso iiialeates which contain a vojretahh! alkah)i(l for a haso, are in general, easily crystallizable and solnhle. ISlaloate of lead is a lumtral salt containing throe atoms of water. To determine the atomic wei:j:ht of inaleic acid, M. Pelouze analyzed nialcute of lead, and found its constituents, when dried, at 248% Malcic acid . . :iO-9r) or ic acid . . 240 or 6*31 Oxide of lead . . 545 or 14 20-31 Ann. 'lo Chiin. el dc I'liys. xxxix. 10. f Jour, dc Pliarnmcic, xxiii. 30. VIXEI) Acins. il Making the atouii(t wol^ht of panimuleic ac'ul fi'Sl. Tlio true weififht is ohviousl^ (i'l^r). This is OIK! ot the most extraonliiiary cxmupli's of isomorisiii at present known. In most other isomeric hodies tliere is a dilfor- enceinthe proportion of water inconil)ination with tiie two isomeric bodies. Ihit in the present ease no such ditt'erence exists. Sonic years ajrt), M. VVinckh;r fomid in the juice of i\w fntmrria ojficinalisy a salt in snndl grains, composed of lime, and a j)eculiar acid, to which he gave the name oij'wnnriv. He sent a (juantity of tiiis acid to M. Lichig, who riMiuested M. Dcniorj^'ay to subject it to analysis. I'lie result of the analysis showed it to be identical with the paramaleic acid of Pelon/e ; and, upon comparing the two acids together, they were found to agree in ever\ rcspi'ct.* Still more lately, M . Schodler has ascertained tliat tho lichemc avid discovered by Pfatf in the ccttaiia IshnuUca, or i and its composition stated. It has been recently examined by lierzelius and JNI. Jules (iay-Lussac, and found exact. We may then consider it as established that its constituents are 4 atoms carbon . . . =3 2 atoms hydrogen . . . =0-25 4 atoms oxygen . . . =4 7-25 But the salts formed by means of this acid have been lately examined by Berzelius, who has shown them to have a much greater tendency to combine with additional portions either of acid or base than any other genus of salts hitherto examined.^ It is of importance to state the results obtained by this distinguished chemist. 1. Citrate of soda. When this salt, whether in crystals or powder, is dried in vacuo over sulphuric acid, and then exposed to the tem- perature of 212*, it loses 17] per cent, of water of crystallization. It undergoes no further loss of weight though heated to 230°. If the salt, after being thus heated, be exposed to the temperature of * Aun. de Chiin. et de V\\\i-. Ivi. 429. \ Auii. der Plianii. xvii. 148. t Ann. dc L'liim. ct de Phys. 'ii. 424. c it a n P v I 1 t'lTItlC ACID. 59 U'iu. 392", it I08O8 12*3 j)t'r cent, of its wt'ij,'ht, without assuming u brown colour or j;ivinif out einpyriMiniatic vapours. If wc now dissoivi' it in water and evaporate to dryness, wo obtain the orij,nnal 100 of citrate of soda cpiito unaltered. It is pretty evident from this statement that the citrate of soda dried over sulphuric acid is composctl of I atom citric acid 1 atom soda .... 4 atoms water 15-75 When heated to 212° it loses 2 J atoms water, and the remainiuj;- 1 ] atoms, which are uu)re intinuitely cond)ined, are driven of by a heat of 31)2". These atomic nundiers when applied to 100 parts of the salt would io, ovev [5 16 19 )0 id 8-25, It is ob- uo, over the true acid is s to be OS.* i, h.iv- is not as an % Th crystals are easily soluble in water, not altered by exposure to the atmosphere. The solution gives a line white precipitate with nitrate of silver ; with sulphate of copper a blue precipitate, which is insioluble in water ; with nitrate of mercury a wliite precipitate. 3. Bipyrotartrate of soda does not crystallize so readily as the preceding salts, but it assumes the same form witli the potash salt. It dissolves readily in water. 4. Barytcs forms with pyrotartaric acid, star-shaped crystals, easily soluble in water, and not altered by er.posure to the atmosphere. 5. The saltof lime isacrystalline powder, difficultly soluble in water. 6. Pyrotartrate of copper is nearly insoluble in water. 7. When oxide or carbonate of lead, is dissolved in pyrotartaric acid, two salts are formed, one soluble and the other insoluble in water, and which therefore may be separated by the filter. When bipyrotartrate of potash is decomposed by nitrate of lead, no preci- pitate appears at first ; but after some days fine needles of bipyrotar- trate of lead are deposited on the sides of the glass. They are slightly soluble in water. When racemic acid is distilled, it yields an acid identical with pyrotartaric acid. SECTION VIII. — OF PYRUVIC ACID. M. Pelouze observed, that when tartaric or racemic acid is dis- tilled in a retort, besides pyrotartaric acid, another acid was formed, which he considered as acetic acid. It was examined by Berzeliug in 1835, and found to be a new acid, which he has distinguished by the name oi pyruvic acid* To obtain it we have only to distil tartaric or racemic acid at the temperature of 392°, and rectify the produce of the distillation, which has a yellowish colour, over the vapour liath. The first half that comes over in this second distillation must be kept separate, because it contains some acetic acid. The last half contains the pyruvic acid. It is a yellowish, somewhat thick liquid, having a weak smell similar to that of a mixture of acetic and muriatic acids. Its taste ii', acid and hot; its specific gravity 1'25. It does not crystallize, ihough cooled down to 23°. It undergoes a slight decomposition every time it is distilled ; this is the reason of its yellow colour ; but the quantity of foreign matter is so small, that the liquid evaporates spontaneously, leaving hardly any residue. Berzelius determined its composition by analyzing anhydrous py- ruvate of silver. It was composed of Oxide of silver 5!)'34 or 1 atom =14'5 or per cent. 59"49 Carbon . 18*36 or 6 atoms= 4*5 — — 18*46 Hydrogen 1*92 or 3 atoms= 0-375 — — 1-53 Oxygen . 20-81 or 5 atoms= 5 — — 20-52 24.375 Jour, ilcr Pharmacie, xiii. 61. F 100 Ml m 111. %''\ ^!^ 66 FIXED ACIDS. Hence the composition of pyruvic acid from tartaric, which is C* H'' O^ by an Hi 18 C H' 0».* It differs from tartaric, which is C* H^ O^ by an atom of bicarbohydrogen ; while it contains 1 atom of carbon and 2 of oxygen, constituting an atom of carbonic acid more than pyrotartaric acid. With the bases it forms a set of salts, which, when in crystals, give to the finger drawn over them the same sensation as talc. They crystallize only when they are prepared cold. When their solution is heated, and they are then evaporated, in vacuo, over sulphuric acid, they assume the appearance of gum. Concentrated sulphuric acid decomposes the pyruvates with difficulty. No smell is observed when the mixture is cold. When heat is applied the mass becomes black, and a smell like that of muriatic acid is observed. We cannot in this way obtain concentrated pyruvic acid. Pyruvate of potash is deliquescent ; that of soda crystallizes in large prisms. Pyruvate of ammonia is deliquescent, that of lithia is but little soluble, and crystallizes in grains ; that of barytes cry^*^ I'lizes in scales. It contains I atom of water, which it loses at 212°. Pyruvate of strontian is in small grains, but little luiluble in cold, but much more so in hot water ; pyruvate of lime furins a crust 111 grains. When dissolved in cold water and evaporated, it assumes the appearance of gum. Alumina, glucina, and yttria, 1 ' ;it neutral insoluble salts, having the aspect of gum, and subsalts . the form of flocks. Pyruvates of zinc, iron, manganese, nickel, and (u /"t, are little soluble, and have the form of grains, which are deposited as soon as the solution is saturated. They contain three atoms of water. Zinc and iron dissolve in pyruvic acid, giving out hydrogen. Py- ruvate of lead is precipitated in a white crystalline powder. It is little soluble in water, but dissolves in an excess of acid, and assumes the appearance of gum. When heated to *212° it becomes yellow. It contains an atom of water, which it does not lose at 248". But it becomes orange. Pyruvate of silver is snow white, and little soluble. It contains no water. When distilled it gives out acetic acid, mixed with a little pyruvic acid, and leaves a residue of silver and char- coal. SECTION IX. OF RACEMIC ACID. This acid has been described in the Chemistry of Inorganic Bodies (vol. ii. p. 69), under the name of vinic acid. But the term racemic acid, given it by M. Gay-Lussac in 1828, is better, because in some parts of the continent vinic acid is the name given to tartaric acid-t I stated, from some imperfect experiments which I had made on a small quantity of this acid, given me by M. Kestner, the original discoverer of it, my suspicion that its atomic weight was 8*5. But having been since supplied with a large quantity of racemic acid, by * Poggendotf's Annalen, xxxvi. 10. f The German name for tartaric acid is weinsiiure, moaning wine or vinic acid. tl o tl a di so w cc N hai in ha wii RACEMIC ACID. 67 Py. It is ■iodies Icemic some Karic K " \ M M' icid. the liberality of Mr Edmond Thomson of Manchester, I was en- abled to make a pretty full set of experiments on its combinations. These experiments, after lying by me for two or three years, were published, in 1835, in the Records of General Science (ii. 97, 161, 241).* These experiments leave no doubt that tartaric and race- mic acids are isomeric; yet the operations of the two are very different. They both form doubly oblique prisms, but in tartaric acid M on M' is . . . 88° 30' In racemic acid .... 68° In tartaric acid P on M or M' is . 97° 10' In racemic acid . . . . 75° The lustre of tartaric acid is glossy, that of racemic acid silky. When racemic acid is heated to 150°, it loses its crystalline from, and gives out 5-59 per cent, of water. At the same temperature the crystals of tartaric acid undergo no change, and lose no weight. When the heat is increased, racemic acid undergoes no farther change till it reach the temperature of 370°, when it assumes a yellow colour, and begins to nndergo decomposition. At 250° tartaric acid liqui- fies, and loses about 4 per cent, of its weight. By this heat its na- ture is altered, for it forms salts with bases quite different from tar- trates. At the temperature of 49°, 100 parts of water dissolves 14'1 parts of racemic acid crystals ; while they dissolve at the same tempera- ture 64' 8 parts of tartaric acid. When racemic acid is dropt into a solution of chloride of calcium, a copious precipitate falls ; while tartaric acid occasions no imme- diate precipitate when added to this chloride. But both of these acids possess the property of preventing the solution of antimony in muriatic acid from being precipitated by water. Berzelius analyzed racemic acid, and informs us that he found its constituents the same as those of tartaric acid, namely, 4 atoms carbon . . . =3 2 atoms hydrogen . . =0-25 5 atoms oxygen . . . =5 Atomic weight . . 8 '251 Now I found racemate of lead composed of Racemic acid . . . 8*206 Oxide of lead . . . 14 * From a paper ijy Berzelius on racemic acid, it appears that M. Walchner has also examined the racemates, and that his experiments have been inserted in the third edition of L. Gmelin's Handbuch der theoretischen Chemie. Not having seen tliat edition, I do not know iio^v far Walchner's experimen'j agree with my own. f Annates de China, et de Phys. xlvi. 128. ii i k I liit ' 4-„_ J 66 FIXED ACIDS. 8-224 And racemato of potash Kaccinic acid Potash ..... And racemic acid crystals of Raceraic acid . . 8-25 or 8-202 Water . . . 2-263 or 2-25 These numbers come so near 8-25, the atomic weight of racemic acid, as determined by Berzelius, that there can be no doubt that its con- stitution is the same (so far as the number of ultimate elements goes) with that of tartaric acid. The crystals of tartaric acid contain only 1 atom water, while those of racemic acid contain 2 atoms. But the difference between the characters of these two acids will be better understood if we compare together some of the principal tartrates and racemates. 1. Racemate of ammonia. This salt is best formed by adding racemic acid to a solution of carbonate of ammonia, till all efferves- cence is at an end. The crystals are beautiful, consisting of doubly oblique prisms, whose faces are inclined at an angle of 94° 45'. They effloresce slightly in the atmosphere, and have a specific gra- vity of 1-639. Taste saline, and cooling. 100 parts of wateV at 60° dissolve 14-58 of this salt. Insoluble in alcohol, or almost so. tuents are 1 atom racemic acid . . 8-25 I atom ammonia . . . 2-125 0-5625 Its consti- ^ atom water 109375 When ammonia or its carbonate is cautiously droj)t into a solution of racemic acid, biracemate falls in bulky flocks, consisting of minute crvstals. Tartrate of ammonia. The taste of this salt is saline, very like that of sal ammoniac. It usually forms gritty crystals ; but it may be obtained in large transparent four-sided prisms, the base of which meets the adjacent faces at angles of 120° and 60°. In general all the edges are replaced by tangent planes, making an eight-sided prism, with angles of 135°. At 55°, 100 parts of water dissolve 60-03 parts of it, so that it is at least four times as soluble as race- mate of ammonia. Its constituents are 1 atom tartaric acid . . 8-25 1 atom ammonia . . . 2-125 1 atom water . . . . 1-125 11-5 Thus it differs from racemate of ammonia, by containing twice as much water of crystallization, by being mucli more soluble in water, and by the shape of its crystals being different. 2. Racemate of potash. It crystallizes in large transparent crystals, like may which •cil all iiileil isolve race- llACEMIC ACID. 69 which are right ohruiue four-sided prisms, whose faces are inclined ut angles of 120° and 00°. The edges of 60° are usually replaced by planes, making unequal angles with the adjacent faces. The terminal edges are almost always replaced by tangent planes, con- stituting a four-sided pyramid, with very uiuujual faces. Taste saline, harsh, and bitter, ijpecitic gravity 2'08. At 55° 100 parts of water dissolve 1 12'59 of this salt. It is not -cnsibly soluble in alcohol. It is composed of 1 atom racemic acid . . 8*25 1 atom potash . • . 6 1 atom water . . . 1*25 15-375 In general the water amounts to 1*32; the 0*195 (about ^ of an atom) of excess is doubtless lodged mechanically between the plates of the crystals. Tartrate of potash. Crystals large, right oblique transparent prisms, the faces of which are inclined at angles of 89" 30' and 90" 30'. 'The obtuse edges are generally replaced by tangent planes. Taste saline, and unpleasantly bitter. Specific gravity 2*140. Dissolves at 50" in its own weight of water, according to Wenzel. Its constituents are 1 atom tartaric acid . . 8*25 1 atom potash . . . 6*00 2^ atoms water 2*8125 17*0625 3. Biracemate of potash. Obtained by mixing a solution of 214 grains of racemic acid crystals with that of 87*5 grains of anhydrous carbonate of potash. A white crystalline powder, reddening vegetable blues, and having an acidulous taste. Specific gravity 2*555. At 55", 100 parts of water dissolve 0*57, and at 108", 1- 12 of the salt. Crystals very irre- gular ; but seem to be six or four-sided prisms and pyramids. It seems anhydrous, and is composed of 2 atoms racemic acid . . 16*5 1 atom potash ... 6 22-5 Bitartrate of potash is less soluble in water, and contain? 2 atoms of water in its crystals. 4. Racevhitc of soda. Crystallizes in small rectangular prisms. Taste saline, and bitter. Sp. gr. 1*511. Not sensibly soluble in alcohol. 100 parts of water at 03" dissolve 31*73 parts of it. When heated it does not melt like racemate of potash, but becomes brown, froths and burns with flame, leaving carbonate of soda, coloured by charcoal. It is anhydrous, or contains only ^ of an atom of water. Its constituents arc stals, lt;| jl I 70 FIXED ACIDS. 1 atom raceniic ucid I atuiu soda Water 12-25 0177 12-427 Tartrate of > 17-375 Tartrate of lime. A white tasteless powder, having the sp. gravity of 1-9000. 100 parts of water at 58" dissolves 0-013 of it, while 100 of boiling water dissolves 0-17. When heated nearly to red- ness, it burns like tinder, and leaves carbonate of lime. Its composition seems to be exactly the same as that of racemate of lime. But as this is scarcely the case with any other pair of these salts, the subj(!ct still seems to deserve further investigation. 8. Racemate of magnesia. A tasteless powder having a sp. gravity of 1-980. 100 parts of water at 64" dissolves 0-05 of it. When heated, it burns like tinder, and leaves magnesia. Its constituents are 1 atom racemif. acid . . 8-25 1 atom magnesia . . . 2-5 2 atoms water 2-25 13 Magnesia alba may be dissolved in racemic acid, and by washing the salt we get rid of almost all excess of acid. The racemate thus formed has a specific gravity of 1-32, and is composed of 1 atom racemic acid . . 8-25 1 atom macnesia ... 2-5 atom magnesia 4^ atoms water 5-0025 15-7525 Tartrate of magnesia. A snow-white powder consisting of very minute crystals. Nearly tasteless, but giving, when kept in the mouth, a slight impression of bitterness. Sp. gr. 1-960. 100 parts boiling water dissolves 0-6 of it. Cold water dissolves nearly as much. Its constituents seem to be *!i ; IMAGE EVALUATION TEST TARGET (MT-3) ^/ ..V .v^ iO^" i'^j^ 1.0 1.1 to 121 |2.5 2.0 us u lAO 1.8 1.25 II U 1.6 ^ 6" ► o 7 Hiotographic Sciences Corporation 23 WEST MAIN STREET WEBSTER, N.Y. 14580 (716) 872-4503 72 FIXED ACIDS. 1 atom tartaric acid 1 atom magnesia 2 atoms water 8-25 25 2'25 13 or the same as that of one of the racemates. 9. Racemate of alumina, Racemic acid does not dissolve alumina, but, by digestion, converts it into a bulky white powder, tasteless and insoluble in water, and composed of 1 atom racemic acid . . 8*25 1 1 atom alumina . . . 3*141 2 atoms water . . . 2*25 13'64l But the two-thirds of the atom of alumina may have been only me- chanically mixed with the salt. Tartaric acid dissolves hydrated alumina with ease, and forms a viscid transparent matter like gum arabic. It is tasteless and neutral and composed of 1 atom tartaric acid . . 8*25 1 atom alumina . . . 2*25 1 atom water .... 1*125 11*625 10. Racemate of iron. Racemic acid dissolves iron with evolu- tion of hydrogen gas, and soft white needles of racemate of iron are deposited. But it is most easily obtained by mixing solutions of sulphate of iron and racemate of soda in the atomic propor- tions. A white or greenish crystalline matter having an inky taste. 100 parts of boiling water dissolves 0*4 of it, and water at 58" dissolves nearly as much. When heated to 400, it catches fire and burns like tinder. It is composed of 1 atom racemic acid . . 8.25 1 atom protoxide of iron . . 4'50 1 atom water .... 1*125 13*875 Peroxide of iron combines with racemic acid, and forms a red- coloured salt having a harsh and astringent taste. 11. Racemate of manganese. It may be formed by digesting car- bonate of manganese in a solution of racemic acid. The carbonate gradually assumes a flesh-red colour, being converted into race- mate. When this salt, after being washed and dried, is put into the mouth it gives a slight impression of sweetness. Sp. gr. 1*960. 100 parts of water at 55° dissolve 0*048, and at 2I2« 0*14 of this salt. Its constituents are ;! IIACEMIC ACIU. 73 I atom racemic acid 1 atom protoxide of manganese 2 atoms water 8-25 4-5 2-25 15 Tartrate of manganese crystallizes in line flesh-red four-sided prisms, apparently rectangular. This salt is more soluble in water, but its composition is the same as that of the racemate. 12. Racemate of nickel. A fine green powder, tasteless, but leaving a disagreeable impression in the mouth. Sp. gr. 1 '76 176. 100 parts of water at 57° dissolves 0*056, and 100 parts of boiling water 1*724 of it. The solution has a fine green colour, and, when cooled, slowly deposits the salt in small crystals, which seem to be flat rectangular prisms. Its constituents seem to be 1 atom racemic acid . . 8*25 1 atom oxide of nickel . . 4*25 2 atoms water . . . 2*25 a red- 14-75 13. Racemate of cobalt. Colour a fine deep violet. It is taste- less, yet leaves a disagreeable impression in the mouth. Sp. gr. 1-769. 100 parts of water at 60°, dissolves 0-118, and 100 parts of boiling water 0-42 of it. The solution has a pretty deep red colour ; but it does not yield crystals. Its constituents are 1 atom racemic acid . . 8*25 1 atom oxide of cobalt . . 4-25 5 atoms water . . . 5-625 ^ 18-125 14. Racemate of zinc. A soft white powder, having a slight shade of buff". Taste weak, but similar to that of the salts of zinc. Sp. gr. 1-980. 100 parts of water at 60° dissolve 1-067, and 100 parts of boiling water 2-58 of it. When the solution is cooled slowly, it deposits beautiful silky crystals. They are flat four-sided prisms, having some resemblance to benzoic acid . Its constituents are 1 atom racemic acid . . 8-25 1 atom oxide of zinc . . 5-25 4^ atoms water . . . 3-9375 17-4375 15. Racemate of cadmium. A beautiful white salt crystallized in small needles. Tasteless. Lustre satiny. Sp. gr. 2-64. 100 parts of water at 52°, dissolve 0-105, and at 212", 0-206 of it. Its con- stituents are 1 1 4J atom racemic acid atom oxide of cadmium atoms water 8-25 8 5-0625 21-3125 ilil } H 74 FIXED ACIUS. 16. Racemate of lead. A white crystalline tasteless powder. Sp. gr. 3*168. 100 parts of water at 60° dissolves 0*021, and at Sl'i" 0*088 of it. Its constituents are 1 atom racemic acid . . 8*25 1 atom oxide of lead . . 14 4| atoms water . . . 5*245 27*495 When exposed to a heat of 100" it loses all its water except 1^ atoms. Hence it is probable that the chemically combined water is only 1 J atom. This would reduce the atomic weight of the salt to 23*9375. The tartrate of lead is an anhydrous salt. 17. Racemated suboxide of mercury. This salt precipitates in the state of a white powder when solutions of nitrated suboxide of mer- cury and racemate of soda are mixed together in atomic proportions. It is a white powder having a slight mercurial taste. Sp. gr. 2*525. 100 parts of water at 195" dissolve 0*0296 of it. It is anhydrous and composed of Racemic acid . . 8*25 Suboxide of mercury . . 26 34*25 18. Racemate of silver. This salt precipitates when nitrate of silver and racemate of soda are mixed in atomic proportions. It is a white powder, but becomes black when heated. Sp. gr. 3*168. 100 parts of water at 100° dissolves 0*268 of it. Has a slight taste similar to that of the other salts of silver. Its constituents are 1 atom racemic acid . . 8*23 1 atom oxide of silver . . 14*50 \ atom water .... 0*5625 23*3125 19. Potash racemate of antimony. This salt, which is analogous to tartar emetic, may be formed by boiling together bird te of potash and glass of antimony. White. Crystallizes in four-sided prisms. Sp. gr. 2*589. 100 parts of water at 48" dissolve 4*11, and at 130°, 14 of it. Like tartar emetic it possesses emetic qualities. Indeed, when adminis- tered, it cannot, as far as its action goes, be disti iguished from tartar emetic. When heated, it blackens and burns lik j tinder. Its con- stituents are 2 atoms racemic acid . . 16*5 1 atom potash ... 6 2 atoms protoxide of antimony . 18 3 atoms water . . . 3*375 43*875 Tartar emetic contains onlv two atoms water. il OXALHYDRIC ACIU. 75 ler. Sp. at Ql'i" SECT. X. — OF OXALHYDRIC ACID. xcept Ig water is le salt to ;es in the ; of mer- portions. gr. Sp. nitrate of ns. It is r. 3-168. fflit taste are nalogous te of \9. 100 Like adminis- m tartar Its con- Scheele upon mucous observed, that when dilute nitric acid was made to act bodies under peculiar circumstances, an acid was formed, which he could not crystallize, and which possessing several properties in common with the malic acid, which he had extracted from various fruits, he considered as identical with that acid. Fourcroy and Vauquelin many years after repeated the experiments of Scheele, and drew from them the same conclusions that he had done. The incrystallizable acid obtained, when nitric acid is made to act upon sugar, gum, and various other bodies, was generally admitted by chemists, to be the same with the malic acid of fruits. Trommsdorf seems to have been the first chemist who thought of examining minutely the characters of this artificial acid. He found them different from those of malic acid, and therefore announced that the artificial acid was a peculiar acid sui generis* In the year 1831, M. T. Guerin Varry made a set of experi- ments to determine the point, and finding the artificial acid to possess peculiar properties, he determined its composition, and distinguished it by the name of oxalhydric acid. He drew up a minute account of the chai-acters of this acid, and of the salts which it forms.t It will be proper to state the most important of the facts which he has ascertained in this place. The oxalhydric acid is noticed in the work on the CJiemistry of Inorganic Bodies (ii. 80), as probably constituting a new and peculiar acid, in consequence of the experiments of Vogel, published as long ago, as 1819.t The statements of Vogel have been fully confirmed by the experiments of M. Guerin Varry, of which I shall now give the substance. M. Guerin prepared the oxalhydric acid which he examined by the following process. 1 part of gumarabic, and 2 parts of nitric acid diluted with half its weight of water, were put into a retort capable of holding four times the bulk of the substances introduced. The retort was attached to a globular and tubulated receiver. A moderate heat was applied till the gum was all dissolved. When nitrous vapours began to appear, the retort was removed from the fire. When the disengagement of nitvous gas was at an end, the liquid was kept gently boiling for an hour. It was then diluted with four times its weight of water, and saturated with ammonia. Nitrate of lime was dropt into the liquid, to throw down the oxalic acid formed during the process. The reddish yellow liquid being filtered, was precipitated by acetate of lead. The oxalhydrate of lead which fell was collected on a filter and thoroughly washed with water. It was then mixed with water, and the lead separated from the acid by a current of sulphuretted hydrogen gas, or it may be separated by sulphuric acid diluted with six times its weight of water. Oxalhydric acid thus obtained was yellow. It was evaporated by a gentle heat, to the consistence of a syrup, it was then saturated * Ann. de China, et de Phys. liv. 320. + Ibid. xHx. 282, and lii. 318. X Gilbert's Annalen, ixi. 233. 76 FIXED ACIDS. i 1; with ammonia, and evaporated till it began to crystallize. The crystals were dissolved in water, and deprived of their colour by animal charcoal. The salt was then decomposed by acetate of lead, and the lead separated by suli)huretted hydrogen as before. The liquid thus obtained was colourless. It Mas evaporated to the consistence of a syrup, and then dried, in vacuo, over sulphuric acid. The acid could not be made to crystallize, but constituted a white solid matter, composed of two atoms oxalhydric acid, and 1 atom water. Sugar or starch may be employed to form oxalhydric acid, instead of gum. 1000 parts of gum yield 2*8 parts, 1000 of starch 3*1 parts, and 1000 of sugar 3*5 parts of dry oxalhydric acid. Oxalhydric acid has a sour taste ; but is destitute of smell. Its specific gravity at 68° is 1*416. It is very deliquescent, and after having absorbed moisture from the atmosphere, its specific gravity is reduced to 1*375. It is very soluble in water and alcohol; but these solutions cannot be made to yield crystals. It is also very soluble in ether. Lime, barytes, and strontian water are precipitated by oxalhydric acid ; but the precipitates are redissolved by a slight excess of the acid. It precipitates in bulky flocks, the subacetate, acetate, and nitrate of lead. The precipitate is insoluble in cold water, and in an excess of oxalhydric acid. But it is slightly soluble in boiling water, from which it precipitates, as the liquid cools, in small scales. When exposed to the action of heat, it is decomposed very readily, and leaves a charcoal of difficult incineration. When heated in a tube, it leaves a residue, which when cooled without contact of air, and then projected into the atmosphere, suddenly becomes red hot in globule, leaving traces of a thick vapour. When oxalhydric acid dissolved in water, was left for a month in a phial, with a ground stopper, it deposited crystals having the shape of those of oxalic acid, but possessing the properties of oxal- hydric acid. M. Guerin who obtained them, considered them as crystals of oxalhydric acid. But M. Erdmann has since shown that they are crystals of tartaric acid. It does not precipitate potash from a concentrated solution like tartaric acid. But it agrees with that acid in precipitating lime, barytes and strontian waters, which malic acid is unable to do. It dissolves zinc and iron with the evolution of hydrogen gas. The concentrated solution of oxalhydric acid may be kept for months without undergoing any sensible change ; but when diluted with water, it deposits a mucilaginous matter in a few di«ys. When 1 part of oxalhydric acid was mixed with 3 parts of nitric acid, and left in a phial with a small opening for a month, being well agitated every day, it deposited a great number of crystals of oxalic acid, while deutoxide of azote was disengaged. When heated with nitric acid it is converted into oxalic acid and carbonic acid. : F it ca CO ac tai mi T WJ mj m( pr tw W( its pe en Fi f and 1 0. jas. :ept for diluted ■ nitric being stals of MUCIC ACID. 77 To determine the atomic woii;;ijt of oxalhydric acid, M. Guerin Varry analyzed oxalhydrate of lead, and found it composed of Oxalhydric acid . 4034 or !)*406 Oxide of lead . 59'66orl4 100-00 According to this analysis, the atomic weight is 9*460 or 9*5. He subjected it to an ultimate analysis by means of oxide of copper. The following table shows the result, when he employed oxalhy- drate of lead, and oxalhydrate of zinc. From salt of lend. Carbon 31-35 Hydrogen 4-08 Oxygen 64-57 From salt of zinc, 33-14 3-65 63-21 100 I 4 atoms carbon . = 3 3 atoms hydrogen . = 0-375 6 atoms oxygen . = 6 Mean. 32-25 3-86 63-89 or per cent 32 _ _ 4 — — 64 9-375 100 From this it appears that its true atomic weight is 9*375, and that it is C* H' 0<5 Professor Erdmann* of Leipzig, has published a set of very careful experiments, to prove that oxalhydric acid has the same composition as tartaric acid. He says, that if a solution of this acid be exposed to spontaneous evaporation, it yields crystals of tartaric acid. Now the constituents of oxalhydric acid as deter- mined by M. Guerin Varry are . . C* H^ O^ Tartaric acid is . C* H^ 0« H O Thus it appears that if oxalhydric acid be deprived of an atom of water, it becomes tartaric acid. It is easy to see how the change may take place. M. Guerin has answered M. Erdmann's experi- ments, and affirms, that both oxalhydric acid and tartaric acid are present in the liquid.! It was called oxalhydric acid by M. Guerin Varry, because if to two atoms of oxalic acid (C O*^) we add 3 atoms of hydrogen (H^) we obtain this acid. Erdmann called it paratartaric acid, because its composition is the same as that of tartaric acid, though its pro- perties are dift'erent. SECTION XI. — OF MUCIC ACID. In the Chemistry of Inorganic Bodies (vol. ii. p. 88), I have endeavoured to show, that mucic acid is composed of C*' H* O^. From the analysis of this acid by Berzelius, the constitution is * Annalen der Pharm. xxi. 1. f Jour, de Pharmacie, xxiii. 416. 78 FIXED ACIDS. h Qa JJ8 o". But M. Mala;?uti lias shown, that in the state in which it was examined by lierzclius, it contained an atom of water, and that the true constitution of the anhydrous acid, is 6 atoms carbon = 4'5 or per cent. 37*5 4 atoms hydrogen = 0*5 — — 4"16 7 atoms oxygen = 7'0 — — 58*33 12 100* So that the true atomic weight of this acid is 12. The analysis of Malaguti has been repeated by Liebig and Pelouze, and found correct.! They found the mncate of silver composed of Mucic acid . . 375-2 or 12-17 Oxide of silver . . 446*8 or 14*5 White mucic ether, discovered by M. Malaguti, was found com- posed of 10 atoms carbon . . =7*5 9 atoms hydrogen . . =1*125 8 atoms oxvjicn . . = 8*0 if' i Now, if from . we substract mucic acid 16*()25 CIO H9 0» C« H* O' there will remain , . . . C^ H^ O which corresponds with an atom of sulphuric ether. It is obvious, from this, that mucic ether is a compound of 1 atom mucic acid, and 1 atom ether. SECTION XII. — OF PARAMUCIC ACID. This acid, which is isomeric with mucic acid, was discovered by M. Malaguti, in 1835.$ If we saturate boiling water with mucic acid, evaporate the solu- tion to dryness, digest the residual matter in alcohol, and allow the alcoholic solution to evaporate spontaneously, we obtain, at first, a white flocky precipitate, and by continuing the evaporation, a crys- talline crust, mixed with crystals sufficiently large, to show that they consist of rectangular plates. This matter has a much more acid taste than mucic acid. It dissolves pretty readily in cold water, 100 parts of cold water dissolve 1*359, and 100 parts of boiling water dissolve 5*8 parts of it, while the same quantity of boiling water dissolves only 1 -5 of mucic acid. As mucic acid is insoluble in alcohol, it might naturally be supposed, that the acid thus obtained by means of alcohol is different from mucic acid. Yet its constituents, determined by the analysis of Malaguti, are identical. He obtained from paramucic acid, in crystlds, * Ann. de Cliim. et de Phys. Ixiii. 86. f Ibid. 182. ♦ % Jour, de Pliarm. xxi. 640. * ) py> r« PAllAMUCIC ACin. Carbon 34*120 or 6 atoms = 4*5 or jjcr cent. 34'28 Hydrogen 4'8(>() or 5 atoms = 0*(I25 — — 4* 76 Oxygen 61-014 or 8 atoms = 8-0 — — 60-96 79 100 13-125 100-00 Now, this is obviously C*' II* O^ + HO, or a compound of 1 atom anhydrous mucic acid, and 1 atom water. This agrees well with the paramucate of silver, which M. Mala- guti found composed of Paramucic acid . 47*65 or 13*198 Oxide of silver 52-35 or 14 5 100-00 The actions of paramucic acid correspond nearly with those of mucic acid ; only in the same bulk of solution, we find less mucic than paramucic acid, and in consequence, the latter has more energy than the former. If we pour a solution of common mucic acid into a solution of protonitrate of mercury, an abundant and very liglit white precipi- tate falls, and the supernatant liquid remains long muddy. When paramucic acid is substituted, there is no immediate precipitate, but gradually a heavy gritty powder falls, leaving the supernatant liquor quite transparent. The same phenomena takes place with nitrate of silver. A little mucic acid precipitates nitrate of silver, while the precipitate is abundant, immediate, and has a mucous appearance. With paramucic acid the precipitate is slow, and falls in a curdy state. The mucates are less soluble than the corresponding paramucates, provided they have not crystallized in their aqueous solutions. The reason of this exception is, that when paramucic acid is allowed to crystallize from an aqueous solution, it is converted into mucic acid. If boiling water be saturated with paramucic acid, crystals are de- posited as the solution cools; but these crystals are insoluble in alcohol, and possess all the cliaracters of mucic acid. If we have saturated solutions of mucic and paramucic acids if boiling water, and saturate each with soda, on allowing the solutic ; to cool, the salts formed are common mucates. If we pour ammonia into two saturated boiling solutions of mucic and paramucic Acids in water, small crystalline plates are precipitated from the latter while still hot, but not from the former. The para- mucate of ammonia is almost insoluble in water, while the mucate is sensibly soluble in that liquid. When paramucic acid is distilled, it yields an acid, identical with pyromucic acid. Malaguti analyzed it, and obtained Carbon .... 53-37 Hydrogen .... 3*90 Oxygen .... 42-73 100-00 I SI 80 riXEU ACIDS. Numbers njnfrcoinf? vory nearly with tlic analysis of the same acitl, by Ilouton Lahillardiore. SEO'ION XIII. — OK PYUOMUCIC ACID. There is notbiiijj;' to add to the aceoutit of this acid, jjiven in the Chemistrif of Inor/fonic Ihdies (vol. ii. p. HH), exceptiuj,^ that the formula for its composition should be (from a comparison of the analyses of Iloutou Labillardiere and Malaj^uti*) 10 atoms carbon = l-^i or per cent. 53T)8 4 atoms hydrogen = 0*5 — — 3*37 (i atoms oxygen = (i — — 42'J)5 14 100 According to Roussingault, when uncombined with a base, it con- tains an atom of water. Hence the anhydrous acid consists of 10 atom^ carbon . . = 7'5 3 ati) hydrogen . . = 0*375 5 atii i oxygen . . =5 r2'875 j'l' i 1)1. !• tm SECTION XIV. — OF JIECONIC ACID. Chemists are indebted to j\f. Kobicpiet for an important set of experiments on this acid, and for the discovery of metamcconic and ptft'omeconic acids, which had been jjreviously compounded with it.f And to M. Licbig, for an accurate analysis of ineconic and metame- conic acids.X The easiest method of procuring meconic acid from opium, is to make an infusion of opium with water, acidulated with sulphuric acid. This infusion is mixed (according to the process of Drs Robertson and (Jregory) with a (juantity of chloride of calcium, sufficient to throw down the sulphuric and meconic acids in com- bination with lime. This precipitate is washed, first with cold water, and afterwards with boiling alcohol. It is next mixed with ten times its weight of water, and heated to about 194°. We then add to it by little and little, agitating violently, a ijuantity of muriatic acid, sufficient to dissolve the meconate of lime, which constitutes the greater part of the precipitate. The liquid is poured upon a filter, previously washed with muriatic acid. On cooling, it de- posits numerous light and brilliant crystals of bimeconate of lime. Dry these crystals by pressure between the folds of a cloth, dissolve them in hot water, and add a sufficient quantity of muriatic acid to decompose the salt. Keep the liquid for some time hot, but not raised so high as 212". On allowing the liquid to cool, crystals af ineconic acid are deposited. If these crystals, as sometimes liap-- * Jour, der Pharmacio, xxi. 641. f Ann. de Chim. ct de i'liys, li. t2;5G, and liii. 4iJ5. X Ibid. liv. 26, and Aunalen der Pliarmacic, vii. 237 ; or Jour, der Pliarmacie, XX. 21. % MBCONIC ACID. 81 con- cium, coin- cold with e then uriatic itutes pon a it de- lime, issolve acid to )ut not tals af s Viap- pons, aro mixed with himoconato of il:n( , wo must repeat the treat- ment with muriatic acid, or separate the crystals uf hiincconato, which aro much lighter, h\ levigation. To deprive it of its colouring matter, let it bo saturated by a dilute solution of caustic potash. DissoWe the meconatc of potash formed in a small quantity of hot water, let it cool, and expose the resulting magma to pressure. Dissolve and crystallize the salt anew, and finally decompose it by muriatic -cid. Meconic acid thus obtained is not altered by exposure to the air. When exposed to a temperature from 212" to 248°, it loses 21*5 per cent, of its weight, ^^ut this loss is not owing merely to the escape of water ; carbonic acid is also j."iven off, and the acid is partly converted into metamcconic acid. It becomes gradually white and opaque. When once rendered as dry as possible, the Iirocess of decomposition stops ; but it cojumonces again if we add a ittlo water. Dry meconic acid is entirely dcotroyed, when the tcmperatire is raisetl sufficiently high. First a peculiar acid distils (>ver, to which the name of pyromeconic acid has been given. It is accompanied by a little water, and a little acetic acid, and is at first nearly colourless. After this an oil passes over, which becomes solid, and there is disengaged a little carbonic acid and inflammable gas. Towards the end of the process a few needles sublime, constitut- ing another acid, which has not hitherto been pnrticularly examined. Meconic acid is soluble in four times its weight of hot water. When the solution is long boiled, it becomes gradually yellowish, then red, and at last, deep brown, at the same time, carbonic acid is disengaged, and the acid is changed into metamcconic acid, which is no longer altered by the water. This change may be produced by the action of the water-bath continued for several days. The new acid precipitates during the cooling. The change goes on still better if we boil a meconate, mixed with an acid, capable of com- bining with its base. Meconic acid crystallizes in white transparent scales. It is not altered by cold sulphuric or muriatic acid. Dilute nitric acid, con- verts it into oxalic acid. To determine the atomic weight of meconic acid, Liebig* lyzed meconate of silver, and found it composed of Meconic acid . . I(i8*8 or 12-73 Oxide of silver . . 192-2 or 14-5 ana- 3G1.0 He analyzed meconic acid, and obtained) Cai'bon 41-54 or 7 atoms = 5-25 or per cent. 42 Hydrogen 2-07 or 2 atoms = 0-25 — — 2 Oxygen 56-39 or 7 atoms =7 — — 5() I 'I armacie, 12-5 * Annalcn der Pharmacie, vli. 239. G 100 •9 FIXED ACinn. 1 i !' i 11 ; ! Aocordinff to UiIh (lotorminntion, the atomic weight of tneconic ncid i» 12'ft, which nppronc^hcs pretty nearly to the iniinl)cr obtained hy analyzing nieconate of silver. DoiibtlesH, the ditFerenoo i§ owing to the difficulty of obtaining mcconate of Hilver perfectly anhy- drous. Meconic acid cond)ine.s with bases in three pronortions ; it forms with them neutral salts, bisalts, and disalts. The bisalts are dif- ficultly deprived of their bases, they strike a very deep red with tho pcrsalts ot iron. This colour disappears when the iron is reduced to protoxide, but reappears when tht^ metal is again pcroxidizcd. Meccmates of potash and amnu)nia becouu? less soluble when they contain an excess of acitl. The neutral meconates of barytes, strontian, lime, lead, are almost insoluble ; but become soluble when they contain an excess of acid. l'h(> uu'couates are, in gem>ral, insoluble in alcohol. When an olcoholic solution of acetate of soda is poured into tincture of opium, mecouate of soda ]»recipitates. When nitrate of silver is poured into a solution of meconic acid, and a little more nitric acid added than is sufficient to dissolve tho meconate of silver ; if we heat the liipiid, the salt is converted into cyanide of silver. The li(]uid at first limpid, becomes «rradually filled with flocks of cyanide. . It contains also oxalate of silver in solu- tion. If too much nitric acid be added, miuh oxalate of silver is formed, but no cyanide. For these curious facts wc are indebted to Liebig. SECT. XV. — OF PYUOMECOXIC ACID, This acid was first examined by Robicpiet in 1832. It is obtained when meconic or parameconic acid is distilled. It melts, when heated to 248", and then has the appearance of an oil. It volatilizes at a gentle heat. It is soluble in water, and still more soluble in alcohol. Muriatic, sulphuric, and nitric acids act upon it as they do on nietameconic acid. Like the meconic and metameconic acids it reddens the persalts of iron. Meconic or metameconic acid, when distilled, gives about one- fifth of its weight of jnrouiecouic acid. It is purified by pres- sure between the folds of blotting j)aper and repeated crystalliza- tions. Robiquct analyzed the pyromeconate of lead and found it com- posed of Pyromeconic acid . i;J02'7 or 13'07 Oxide of lead . KJDO-O or 14 2(;97-7 According to this analysis the atomic weight of pyromeconic acid is about 13. He analyzed tho crystallized pyromeconic acid and anhydrous pyromeconate of lead, and obtained I METAMECONIC ACID. 83 onc- :oin- liil is rous I''rnm Ariil. rrom !U1t nf iMi. Carhon 52-70 58-7 I lydrojjffn :j-(i4 2-9 Oxygen 4:J-(i(i :jh-4 100-00 j 100 Now the numhers cnrrcrtpondiii;? with tliis analysifl and with the atomic wtMijht of pyroincconic acid uro 10 ntDuis'carhon = 7-r) or per cent. 58-25 3 atoms hydrojron = 0-.*}75 — — 2-91 5 atoms oxygen =5-0 — — 38-84 I2-H75 100 The crystals are C" II' ()", or tiicy are pyromeconic acid com- bined with an atom of w.jffr.* This constitution of p\ romoconic acid enables us to explain its formation from the other two acids. Metameconic acid . C* H* 0>" Subtract 2 carbonic acid C ()* 1 water . . HO Remain . . . C" IP O" which is an atom of pyromeconic acid. So that metameconic acid may be resolved into 1 atom pyromeconic acid, 2 atoms carbonic acid, and 1 atom water. 2 atoms meconic acid are . C* II* O'* Subtract 4 atoms carbonic acid C* O" 1 atom water . HO Remain 1 atom pyromeconic C'*^ H" O* So that 2 atoms of mecomic acid may be resolved into 1 atom pyro- meconic acid, 4 atoms carbonic acid, and 1 atom water. SKCT. XVI. — OF METAMECONIC ACID. This acid, as has been already observed, was first accurately dis- tinguished from mecoTiic acid by M. Robiqnet in 1832.t The best method of obtaining it is to dissolve meconate of potash or of lime, to add the reciuisite quantity of muriatic acid to decom- pose the salt, and then to boil the rKpiid for some time. The me- tameconic acid precipiiates nuich less soiled with colouring matter than when we decompose mec(mic acid by boiling it in water. It is rendered colourless by treating it with animal charcoal. Like meconic acid it strikes a red with the salts of peroxide of iron. It is less soluble in water than meconic acid. Its crystals are hard and granular, and require about 1(3 times their weight of water to dissolve them. Muriatic acid does not alter them. Sul- phuric acid destroys them by long-continued boiling. Nitric acid • See Ann. dc Cliim. et de Phys. li. 251. Ibid. li. 236. !l 84 FIXED ACIDS. M\ m< converts them into oxalic acid. When distilled they give pyrome- conic acid. Liebig* analyzed raetameconate of silver in order to determine the atomic weight of the acid. It was composed of Metameconic acid . 125'7l or 19*96 Oxide of silver . 91'ii9 or 14*5 2r7M0O" He analyzed the acid and obtained Carbon 45*8 or 12 atoms = 9 or per cent. 46*15 Hydrogen 2*7 or 4 atoms =0*5 — — 2*57 Oxygen 51*5 or 10 atoms =10 — — 51*28 i00~ 19*5 100-00 According to this constitution the atom of metameconic acid is 19*5. From this composition it is easy to see how meconic acid, by the abstraction of carbonic acid, is converted into metameconic acid, Meconic acid is . . C^ H^ O^ Subtract 1 atom carbonic acid C O'^ There will remain C« H^ which is just half an atom of metameconic acid. 0» SECTION XVII. OF GALLIC ACID. ' The history of gallio acid, and the most economical process for obtaining it have been given in the Chemistry of Inorganic Bodies (vol. ii. p. 99). When pure it does not alter the transparency of a solution of isinglass. The crystals are colourless needles, which, according to Braconnot, require 100 times their weight of cold water to dissolve them. When dropt inlo a solution of persulphate of iron, a deep blue precipitate falls, much more soluble than tannate of peroxide of iron. This precipitate dissolves slowly, and without the assis- tance of heat in the liquid in which it was formed ; and after an interval of some days, this liquid becomes almost colourless. Sul- phuric acid takes almost the whole of the iron from gallic acid, and protosulphate of iron crystallizes in the liquid, the iron being reduced to protoxide by the destruction of a portion of the gallic acid. The same changes are produced in a few minutes if we boil the liquor ; and in that case carbonic acid gas is disengaged. Tan- nin exhibits a similar reaction, and in all cases prussiate of potash gives a greenish preci})itate, showing tlie deoxidizcmcnt of the per- sulphate of iron. Gallic acid occasions no precipitate in the salts containing the vcgeta])Ie alkaloids. With barytes, strontian, and lime water, it forms white precipitates, which redissolvc in an excess of acid, and crystallize in prismatic needles, having a satiny lustre, and not altered by exposure to the air. These salts assume various colours, from green to deep red, and are destroyed when exposed the influence of the air, and an excess of base. * Annalen dcr Pharmacic, vii. 420. w Bi P ei ui ai M sa Tl fr( th Si so w; GALLIC ACID. 85 Potash, soda, and ammonia, form, with gallic acid, very soluble salts, quite colourless, while kept from the contact of oxygen ; but when this gas is present, it is absorbed in great quantity, and the salts assume a deep brown colour. Acetate or nitrate of lead, poured into a solution of gallic acid, produces a white precipitate, the colour of which is not altered by exposure to the air.* Gallic acid dissolved in water, and left to itself in an open vessel, undergoes gradual decomposition, a mucilaginous matter is formed, and a black substance, which Dobereiner considers as ulmin.f When the crystals of gallic acid are exposed to a gentle heat, they give out water and effloresce. A quantity of these crystals, dried at the temperature of 248", were analyzed by Pelouze and Liebig, by means of oxide of copper. They obtained Carbon Hydrogen Oxygen M. Pclouzc made two analyses of galla'^e of lead, and found the salt composed of Gallic acid . . 95-3 or 10-7 Protoxide of lead . 124-7 or 14 Pclouzc. 49-51 3-67 46-82 Liebig. 49-17 3-64 47-19 100-00 1 100-00 § 220-0 This makes the atomic weight of the acid 10-7. Now 7 atoms carbon =5-25 or per cent. 49-42 3 atoms hydrogen =0-375 — — 3-53 5 atoms oxygen =5 — — 47-05 10-625 100-00 give an atomic weight which agrees very nearly with that deduced from gallate of lead, and at the same time coincides sufficiently with the mean of the analyses of Pelouze and Liebig. The crystals of gallic acid are composed of ' 1 atom gallic acid • • 10*625 1 atom water . . . 1-125 11-75 Now that we are acquainted with the composition of tannin and gallic acid, it is easy to explain the way in which tannin, by ab- sorbing oxygen is converted into gallic acid, carbonic acid, and water. For 2 atoms tannin C^e H'^ O^^ + 0="* are equal to * Pelouze, Ann. de Chim. et de Phys. liv. 348. t Ann. de Cliini. ct dc Phys. xxiv. 335. X Ibid. liv. 350. § Ibid, Ivii. 419. 86 \'\ I FIXED ACIDS. 3 atom gallic acid 15 atouiS carbonic acid 9 atoms water Q2l jp 0" CIS Q30 IP 0» C36 H'» 0»< Consequently, every two atoms of tannin absorb 24 atoms oxygen, and are decomposed into 3 atoms gallic acid + 15 atoms carbonic acid + 9 atoms water. SECTION XVIII. — OF PYROGALLIC ACID. Berzelius stated it as his opinion that gallic acid, obtained from the infusion of nutgalls by the process described in the Chemistry of Inorganic Bodies (vol. ii. p. 100), was not free from tannin, and that the only method of procuring gallic acid in a state of purity was to sublime it. This opinion was examined by Braconnot,* who showed that waen gallic acid is sublimed, it is converted into a sub- stance possessing quite different properties from the gallic acid of Scheele. He therefore gave it the name of pyroijalUc acid, and showed that gallic acid obtained by his own process is quite pure. These conclusions have been confirmed by the more recent experi- ments of Pelouze.f To prepare pyrogalHc acid we must expose gallic acid in a retort to a temperature between 4 1 0° and 428*^. Pyrogallic acid sublimes. If the temperature be allowed to get as high as 4()4'', not the least trace of pyrogallic acid will be obtained ; but another acid, namely, the metagallic. The best way of preparing pyrogallic acid is to fill a retort half full of gallic acid, and to plunge it into an oil-bath. A thermometer ought to be kept constantly in the oil, that we may be sure that the heat does not get beyond the proper point. Scheele was the first person who obtained pyrogallic acid ; but he was not aware of the difference between it and the common gallic acid.J Deyeux afterwards repeated Scheele's experiment. He dis- tilled with precaution a quantity of nutgalls. Much carbonic acid, a volatile oil, tar, and an acid liquid came over. This last liquid, when filtered and left to spontaneous evaporation, deposited many crystals of pyrogallic acid.§ But Deyeux did not suspect, any more than Scheele, that the acid thus obtained differed from com- mon gallic acid. Pyrogallic acid obtained by sublimation is in crystalline plates, which are white and brilliant, and contain no water. The taste is cooling and bitter. The acid reddens litmus pajjcr. At the tem- perature of 55° it is soluble in 2*25 times its weight of water. It is soluble also in alcohol and ether. When the solution of pyrogallic acid is exposed to the air, it gradually assumes a deep colour, and in a few days is decomposed ; being converted into a substance pos- sessing the characters of ulmin. When sulphuric acid is mixed with pyrogallic acid, and slightly heated, no change of colour or decom- • Ann. de Chiin. vt Je Plivs. xlvi. 206. X Crt'll's Chemical Journal, i. iO. + Ibid, xxxiv. 348. $ Jour, de Plivs. xlii. 416. I'YROGALLIC ACID. 87 |lates, ste is Item- It is rallic and Jpos- Ivvitli bom- posltion takes place ; but at a higher temperature sulphurous acid is exhaled, and the liquid assumes a brown colour. Pyrogallic acid melts when heated to 239° and boils at 410°. Its vapour is colourless, slightly irritating. At the temperature of 482" it becomes black, .ter is disengaged, and there remains be- hind a considerable resimre of metagallic acid. Potash, soda, and ammonia, form, with pyrogallic acid, very soluble salts. Pyrogallate of potash crystallizes in rhomboidal tables, which are beautifully white. This acid occasions no preci- pitate in barytes or strontian water. Nor does it become coloured, unless oxygen be in contact with it. When persulphate of iron is poured into a solution of pyrogallic acid, whether cold or hot, it is instantly changed into protosulphate, and at the same time the liquid assumes a beautiful reddish-brown colour, without depositing any precipitate. No carbonic acid is formed as is the case when tannin or gallic acid is substituted for pyrogallic acid. If instead of pyrogallic acid we employ a pyrogal- late, and mix it with a solution of peroxide of iron, the liquid assumes a deep blue colour, while at the same time a precipitate of the same colour falls. Protosulphate of iron when mixed with pyrogallic acid gives the liquid a blackish-blue colour. Pyrogallic acid was analyzed by M. Pelouze, and by M. Liebig, and M. Berzelius. They obtained Carbon Hydrogen Oxygen Pelouze. 56-74 4-83 .38-43 100-00* Liebig, 56-86 4-86 38-28 Berzelius. 56-64 5-00 38-26 100$ lOO-OOf Berzelius likewise analyzed pyrogallate of lead, and found it composed of Pyrogallic acid . . . 8 047 Oxide of lead . . .14 22-047 showing that its atomic weight is about 8. These results lead to the following atomic constitution of the acid 6 atoms carbon =4*5 or per cent. 57 '15 3 atoms hydrogen =0-375 — — 4-75 3 atoms oxygen =3 — — 38-10 7-875 Its atomic weight is 7*875. Now Gallic acid is Pyrogallic acid Difference * Ann. (le Cliim. et de Pliys. liv. 360. X Annals of Philosophy, v 100-00. C^ H' 0« C« H3 0» C 0^ t Ibid. Ivii. 4*20 176. jji 88 FIXED ACIDS. or an atom of carbonic acid. Heat then decomposes gallic acid into 1 atom of pyrogallic acid, and 1 atom of carbonic acid. This was what M. Pelouze found experimentally to be the case. SECTION XIX. — OF METAGALLIC ACID. This acid was discovered and named by M. Pelouze in 1833.* When tannin or gallic acid is exposed to the temperature of 484°, carbonic acid still continues to come over, but instead of the crystals of pyrogallic acid which appear when the temperature is no higher than 428", water passes over in considerable quantity, and runs down the beak of the retort, and there remains behind a black matter, very brilliant, destitute of taste, and completely insoluble in water. This is the metagallic acid of Pelouze. Potash, soda, ammonia and glucina dissolve it with facility. When an acid is poured into the solution, the metagallic acid pre- cipitates in black flocks, quite unaltered. Metagallate of potash obtained by boiling an alkaline solution, with an excess of metagallic acid in a gelatinous state, produces no change en vegetable blues. It forms black precipitates with the salts of lead, iron, copper, magnesia, zinc, silver, lime, barytes, and strontian. Metagallic acid disengages carbonic acid from che carbonates of potash, and soda, but it has no action on the carbonate of barytes, nor even on barytes water, no doubt in consequence of its great insolubility, and of the equally great insolubility of metagallate of barytes. M. Pelouze analyzed metagallate of silver, and found it com posed of Metaffallic acid . . 86 or 12*428 Oxide of silver 42 or 14-5 i! I 78 He analyzed metagallic acid united to silver, and in a separate state, and obtained Salt of silver. Acid. Carbon . 73-8 66-00 Hydrogen . 3-2 3*74 Oxygen . 23-0 30-26 100-0 100 The analysis of the combined metagallic acid leads to the following atomic quantities 12 atoms carbon = 9 or per cent. 72-73 3 atoms hydrogen = 0-375 — — 3-03 3 atoms oxygen =3 — 24-24 12-375 100-00 \m\, 'ie Cliiiii. ct dn Pl,v?. li\ . a.>2. KINIC ACID. 89 f<\ It is C'» H" 0», and the uncombined acid is C'» H» 0» + H O, or anhydrous acid united to an atom of water. It has been already stated, that when pyrogallic acid is exposed to a temperature of 484" water passes over, and metagallic acid remains in the retort, and that nothing else except these two sub- stances appears. Now 2 atoms pyrogallic acidare C H^ O* Metagallic acid is Qli JJ3 03 Remain . . H» 0« or three atoms of water Thus it appears that when pyrogallic acid is exposed to a temperature of 484° every two atoms of it are resolved into an atom of metagallic acid and three atoms of water. SECTION XX. — OF KINIC ACID. In the Chemistry of Inorganic Bodies (vol. ii. p. 108), I have ascribed the discovery of this acid to Vauquelin. But M. Baup Las pointed out M. Hoffman of Leer, as the discoverer.* Hoffman accidentally observed a quantity of kinate of lime crystallized in an extract of cinchona. Upon examining these crystals, he ascertained that they were composed of lime, combined with a vegetable acid, which was neither oxalic, tartaric, nor citric acid, nor any acid at that time known. He concluded, from his experiments, that it was an acid sui generis^ and he attempted in vain to convert it into oxalic acid, by digesting it in nitric acid.f The only analysis of kinic acid that had been published when the Chemistry of Inorganic Bodies was printed, was that of Henry and Plisson, which was evidently inaccurate. Since that time it has been analyzed by Liebig,t and Baup.§ M. Liebig found the anhydrous acid composed of 15 atoms carbon = 11'25 or per cent. 52*63 9 atoms hydrogen = I* 125 — — 5'26 9 atoms oxygen = 9*00 — — 42* 11 21-375 100-00 But it usually retains at least, 1 atom of water. It was hydrous acid which was analyzed by M. Baup. Hence the reason why he represents its constitution by 15 atoms carbon = 11-25 or per cent. 50-000 1 atoms hydrogen = 1-25 — — 5-556 10 atoms oxygen = 10-00 — — 44-444 22-5 100 Liebig found that crystallized kinate of lime, when dried at 302**, lost 29*58 per cent, of water. One hundred parts of the dried salt, when exposed to a red heat, left a quantity of carbonate of lime, * Ann. de Chim. ct dc Pliys. li. TiT. f Crcll's Annalen, 1790, i. 314. \. Ann. dc Cliiiu. ct dc Fliys. xlvii. 193, and Annulcn dcr Pharmacic, vi. 14. § Ibid. li. ,j8. I 1 90 FIXED ACIDS. ' equivalent to 13*069 of lime. Consequently the crystallized salt con- tained 9*18 per cent, of lime. The dried salt still contained 2 atoms of water. Hence the constituents of the salt are , Kinic acid . 55*4 1 or 1 atom Lime . . 9*18 or 1*01 atom Water . . 35*41 or 12*1 atoms , 1 M ii!' 100 It is clear from this, that the true constitution of the salt is 1 atom kinic acid 21*375 or per cent. 55*70 1 atom lime 3*5 _- _ 9*12 12 atoms water 13*5 — — 35*18 38*375 100*00 It is obvious that two of the atoms of the water are intimately com- bined with the acid. The other ten atoms are water of crystallization. M. Baup has also examined and analyzed several of the kinates. It will be worth while to state here the result of his experiments. 1. Kinate of soda. This salt is easily obtained, by saturating carbonate of soda with kinic acid, and crystallizing by spontaneous evaporation. Its taste is not bitter. At the temperature of 59° it dissolves in half its weight of water. It is composed of 1 atom kinic acid . . . 22*5 1 atom soda .... 4 4 atoms water .... 4*5 31*0 M. Baup could neither obtain kinate of potash nor of ammonia in a crystallized state. 2. Kinate of lime. This salt, which exists in considerable quantity in several species of cinchona, crystallizes in rhomboidal plates with angles of about 78° and 112°, often rendered hexagonal plates by the truncation of the acute angles. They are foliated, and easily split into brilliant folia. It is soluble in six times its weight of water at 61°. Its constituents, as determined by Liebig, are 1 atom hydrous kinic acid 23*625 , 1 atom lime . . . 3*5 10 atoms water . . . 11*25 38*375 3. Kinate ofharytes. It is easily formed, by saturating kinic acid with carbonate of barytes. It crystallizes in dodecahedrons, con- sisting of two six-sided pyramids, applied base to base. M. Baup never observed it under the form of acute octahedrons, described by Henry and Plisson. This salt effloresces. 1 atom hydrous kinic acid 1 atom barytes 6 atoms water It is composed of 22*5 9*5 6*75 38*75 KINIC ACID. 91 4. Kinate of strontian. Its shape is the same as that of kinate of lime. But it is easily distiiirfuished by the rapidity with which it effloresces when exposed to the air ; whereas the kinate of lime re- mains unaltered. At 54° it dissolves in twice its weight of water. It is composed of 1 atom hydrous kinic acid . 22*5 1 atom strontian . . . 6*5 10 atoms water . . . 11*25 40-25 When it is allowed to effloresce, it loses 3 atoms of its water and retains the other 7- 5. Kinate of lead. It crystallizes in needles ; but the solution requires to be so concentrated before it crystallizes, that it is dif- ficult to extract the crystals. When dried, pulverized, and exposed to the air in a warm room, it was found composed of 1 atom hydrous kinic acid . 22' 5 1 atom oxide of lead . . 14 2 atoms water . . . 2*25 38-75 6. Siibkinate of lead. This salt may be obtained by mixing subacetate of lead with kinate of soda, or kinate of ammonia, taking care not to add an excess of subacetate. The precipitated sub- kinate of lead ought to be washed, and dried as completely as pos- sible, excluded from the action of the air, otherwise it will imbibe carbonic acid. M. Baup did not succeed in determining the water which it contains ; but he found the dry salt composed of Kinic acid . . . 27-273 Oxide of lead . . . 72-727 100-000 This corresponds with 1 atom kinic acid 4-285 atoms oxide of lead. Probably it consists of tetartokinate of lead, mixed with a little oxide of lead. We have no evidence that the whole oxide of lead is in combination with the acid. Indeed, so odd a combination as 4-285 atoms oxide of lead with 1 atom kinic acid, is a very improbable thing. 7. Kinate of copper. This salt may be obtained, by dissolving carbonate of copper in kinic acid, taking care to leave a small excess of acid. By evaporation we obtain a greenish salt, which should be redissolved in water, containing a little kinic acid. By repeat- ing this process twice, and crystallizing each time, we obtain the salt pure. It crystallizes in foliated needles, has a pale blue colour, and effloresces in the air, losing f ths of its water of crystallization. When dissolved in water it undergoes spontaneous decomposition, subkinate of copper precipitating. Its constituents are li 92 FIXBD ACIDS. 1 atom kinio acid 1 atom oxide of copper 5 atoms water 22-5 5 5-625 l< i m. 33-125 8. Subkinate of copper. It is obtained by heating a dilute solu- tion of kinic acid in contact with an excess of carbonate or oxide of copper. It forms small brilliant green crystals, not altered by exposure to the air. At the temperature of 64° it dissolves in be- tween 1150 and 1200 times its weight of water. Boiling water dissolves more, and the salt crystallizes on the solution cooling. Its constituents are Kinic acid . . . 57-931 Oxide of copper . . . 27-586 Water .... 14-483 By the analysis of Liebig,* it is composed of 1 atom kinic acid 2 atoms oxide of copper 4 atoms water 35-875 9. Kinate of silver. When a solution of kinate of silver is evapo- rated in the dark by a moderate heat, or under the vacuum of the air-pump, it forms a very white anhydrous salt in little sphericles. When heated it melts, swells, gives out abundant vapours, and leaves metallic silver behind. It is composed of 1 atom kinic acid . . 21-375 1 atom oxide of silver . . 14-5 100-000 = 21-375 = 10 = 4-5 35-875 \Q. Kinate of cinchonina. This salt, at 59**, dissolves in half its weight of water. It contains 4 atoms of water of crystalliza- tion. It is partially decomposed by alcohol. If we dissolve it in a quantity of hot alcohol not suflScient to keep it in solution after be- coming cold, a salt is deposited in brilliant crystals, which arc short prisms, with from 4 to 6 faces truncated obliquely. These crystals become slowly opaque. While transparent they are very soluble in water ; even air, saturated with moisture, causes them to run into a liquid. A little cinchonina separates when we dissolve them. The aqueous solution of these crystals reacts as an acid, the alcoholic solution as an alkali, on litmus paper. 11. Kinate of quinina. This salt, at 52°, dissolves in 3^ times its weight of water, and in 0-88 of its weight of alcohol. It contains 4 atoms of water of crystallization. * Annaleii ilcr I'harmacic, vi. 17. n n n P ti a o g ti c s r ij F c c } il ELLAGIC ACID. 93 3S its Itains SECT. XXI. — OF PYROKINIC ACID. I have ..'•tiling to add to the imperfect account of this acid given in the Chemistry of Inorganic Bodies (vol. ii. p. 110). SECT. XXII. — OF ELLAGIC ACID. Little additional information respecting this acid has been ob- tained by chemists since the account of it inserted in the Chemistry of Inorganic Bodies (vol. ii. p. 104). Pelouze, after drying it as much as possible, subjected it to an ultimate analysis, by means of oxide of copper, and obtained Carbon 55'14 or 7 atoms =5*25 or per cent. 55*26 Hydrogen 2-71 or 2 atoms =0-25 — — '2-()3 Oxygen 42* 15 or 4 atoms =4*00 — — 4211 100* 9-5 100-00 If these atomic numbers be adopted the atomic weight of ellagic acid will be 9*5. Now M. Pelouze found that when ellagic acid was dried in a temperature of 248° it lost 1 1*7 per cent, of its woight, and was then composed of Pure ellagic acid , 88'3 or 8*49 Water . . . 11-7 or 1-125 100-0 If we admit the acid to be a compound of 1 atom anhydrous acid and 1 atom water, its atomic weight, according to this experi- ment, would be 8*5. Now this does not differ more from 9*5, the number deduced from its atomic constitution, than might be ex- pected in an experiment of this nature. From this atomic consti- tution it is easy to see the relation between ellagic and gallic acid. Gallic acid is . . . C^ IP O* C^ W O* Ellagic acid Difference ... HO So that an atom of ellagic acid -f- 1 atom of water constitutes an atom of gallic acid. M. Robiquct mixed 1 part of crystals of gallic acid with 5 parts of concentrated sulphuric acid, in a retort, and applied heat very gradually. The gallic acid was dissolved, and the liquid became transparent. The heat being cautiously increased, the liquid be- came first fawn-coloured, then rose-red, and passed through all the shades of red to crimson, and, at the same time, became viscid. When heated to 284", traces of sulphurous acid began to appear. The process was stopped, the liquid allowed to cool, and then mixed by little and little with cold water. An abundant reddish-brown precipitate fell partly in flocks and partly in small crystals. These crystals were a beautiful reddish-brown like kermes, and exceeded one-half, or approached to two-thirds, of the gallic acid employed. When heated to 248° they lost 10 J per cent, of their weight, and * Ann. de Cbim. et de Phys. liv. 357. I i I 11 I! 94 FIXED ACIDS. their colour waa injured. When heated over the fire they are de- composed slowly, but arc at last charred and covered with little red crystals. Wiien analyzed, they were found composed of C^ 1 1* O*, and of course had the same composition as e/far/ic acid. Lilte tiiat acid they are insoluble in water ; but their l)cluvviour witli the alkalies is ditl'erent. An excess of potash holds ellagic acid in solu- tion, but in ])roportion as the excess of potash combines with car- bonic acid, suHiU scales of elia«>ate of potash, little soluble in water, are deposited. The red crystals neutralize potash ; but no scales fall. After a long interval small crystals appear, having a red colour, and being very soluble in water. llohi(piet found that this red-coloured acid possessed powerful dyeing ])roperties, cloth im- pregnated with iron when treated with them become violet, brown, or black, according to tlie (puuitity of peroxide of iron present. With alum mordant thoy gave the same red colours as madder. Robi(pjet conceives that this red substatu-c exists in nutgalls, aiul is disposed to ascribe to it the use of galls in the process of dyeing Turkey red. But this opinicm is not likely to be correct.* SECT. XXIII. — OF CAHINCIC ACID. This acid was discovered, in 1830, in the bark of the root of the Kaliinfa (chiococca racemosn awimfmjn^ flore- luteo) a ])ljint whicli grows in Brazil, in the province of Minas Geraes, and belongs to the order of ruhiacecB. It is a shrub whicli rises to the height of six feet, or even higher. The bark has a brown colour, an aromatic but disagreeable smell, and an intensely bitter taste. It is hard, brittle and compact, and is easily separated by striking the root be- tween two hard bodies. By the inhabitants of Brazil it has long been employed as a cure for intermittent fevers. But it was first made known in Europe as a valuable medicine by Major Langsdorf. MM. Fran9ois, Caventou, and Pelleticr, received a cargo of it from Brazil, and subjected it to a chemical analysis. The most impor- tant of the constituents discovered in this bark was cahincic acid.f This acid may be extracted from the Kahin9a bark by the follow- ing process : — Digest the bark in alcohol, evaporate the alcoholic solution to dryness, and dissolve the residue in water. Add lime to the solution till the liquid loses all taste of bitterness. A calcareous salt is deposited which is cahincate of lime. Decompose this salt by oxalic acid and the cahincic acid is disengaged. It may be puri- fied by repeated solutions and crystallizations. It may be precipitated directly from the a(pieous decoction of the bark by dropping into it muriatic acid. Tlie acid is deposited slowly, during several days, in the state of small crystals. But when ffot in this wav it is always deci)lv coloured,' and a ijood deal remams in solution, being kej)t from precipitating by the colouring matter. Cahincic acid requires six hundred times its weight of water and * Jour, de Pliarmacic, xxii. 484. t Ann. de Chim. etdc Phys. xliv. 291, and Joiir. de Pliarmacie. xvi. 265. Ig long )f the )sited But deal uring and i\ CAHINCIC ACID. 95 nearly as much other to dissolve it. Hut it is very soluble in alcohol, and when dissolviMl in hot alcohol it crystalli/es as the liquid cools. The crystals are sniall white needles usually in the form of stars. The acid has no smell. When j)Ut into the mouth it appears at first tasteless, but socm jjivcs an im))rc8si(m of intense bitterness. At 212" it loses only a little water of crystallization ; but when stronjjly heated in a fflass tube it l)Ccomcs soft, is charred, and j^ives out white va|)ours, which are deposited in small li;?ht crystals on the sides of the glass. These crystals have no bitter taste and contain no ammonia. Sulphuric acid dissolves cahincic acid and chars it immediately. Muriatic acid dissolves it, but almost innnediately assumes the form of a jelly, which is changed by the addition of water into white trans- lucent Hocks quite destitute of bitterness. Nitric acid acts in the same way, and by a long-continued action it produces a yellow bit- ter matter without any trace of oxalic acid. Dilute muriatic or nitric acid scarcely dissolves cahincic acid. Concentrated acetic acid dis- solves it, and, when assiste« FIXED Arms. II I' \ I i Ji Hut it (loofl not comn nuffli'lontly near I/iobi<:f'a uimlysla to givo ua full contidorn'o in itn affunicy. It is clt'iir that a much j^roator nurnhcr of oxperiincnts and analyses upon a lar^'or (juantity of the acid than Lichig possessed woidd ho requisite before the nature and properties of this curious acid can he accurately understood. SECT. XXIV. — OF lilCOLOIlIN, OH UlCOLoniC ACID. It was observed a j^ood many years aijo, by Lort('ke, that various vejfctables, when dijxestiMl in hot water, i^ivea solution which appears pellow by transmitted liyht, but violit or Nuc by retlected lijiht. The wood of the Gui/diiditin Moringn or li Ten pounds of the bark of the horse chestnut reduced to powder, were mixed with six times their bulk of alcohol, of the specific gravity 0*8631, and digested at tirsi, in a gentle heat, but at last the liquid was made to boil. The alcohol was then drawn oft' while hot, and the bark digested a second time with half the quantity of alcohol used at first. This last portion was then separated from the bark by expression — the tincture was filtered and distilled till sev^n eighths of the whole liquid had passed over. The residue was left exposed for some weeks in an open vessel. The impure bieo- lorin precipitated. It was washed with ice-cold water, to separate it as i'" r as possible from the impure ■ ..atter with which it was mixed. It was then dissolved in a boiling heat, in a mixture of ether and iJcohol. It was deposited from this solution as the liqi'il couled. These solutions and precipitations vvre repeated till the blco'dvin assumed a snow-white colour. It was then considered .-- jM.; ,•. Bieolorin has a snow-white colour, and is nsually in tlie state of a light flocky powder, somewhat resembling carbonate of magnesia in appearance. It is not capable of crystallizing. Its taste is " For this li storioal sketch, I am indebted to Trommsdorf. See Ann. der Pharraacic, xiv. 1^;». t nil. der )'! arnuicie, xiv. 190. i I r u;ivo 118 Limlyaes ould 1)0 u'id can various A lijflit. 'tint, wM 'olour ot* ids, but (0(1 that ; similar [•a which ml men- waa by tner into Martiua not very furnish- In 1835 ration of alyzed it powder, specific at last If while lintity of d from tiled till duo was re bico- eparate mixed, ler and eoiiled... J'' ■' Istatc of ignesia taste is Lnn. dcr BIl HOniC ACID. 97 bittori»h, and it has no smell. It dissolves in 12'00 times its weiizht of boiliiit,' water. The solution on coolini,', concretes into a bulky white ntass. When this white lu iter is dried at 212" it losoa onlv fr<»m O-.'i to 0*7o of its weijfht. U'atcr of the temperature of 51'' dissolve^ only ^f, part of its weiuht of bicoh)rin. At the tempn '-ire of 77*', water dissolves ;Tf i;th of its weii,'ht of it. The .Mpuuiis soluri'^n is ahiuist colourless, i>ut lublo in 24 times its weight of boiling alcohol, of the 8))ecitic gravity ()"7!)H. Hut the greater part precipitates in (locks when Mt(> dution cools. Absolute ether dissolves a scarcely per- ce]itillc portion of bicolorin. It re(pnres seventeen times its weight oft) 11 )u; ' iiiixture, of I jiart ether and 5 narts alcohol, to dissolve it. V\ hen a drop of this solution is let fall on water, it variegatea etro.i^Iy. The aqueous solution loses its variegating quality when mixed with a few drops of sulphuric, nitric, muriatic, phosphoric, or ar-joiiic acids. The same etlect is ])roduced by boracie, tartaric, malic, and even acetic acids. A few drops of ammonia, potash, soda, lime, or barytes solutions restore the variegating property immediately. All alkaline bodies increase the variegating property ; but give a yellow colour to the solution. No precipitate is produced by the alkalies, lime, barytes, or strontian, or their carbonates. All these bodies increase the solubility of bicolorin in water. Acids on the contrary throw it down. Chlorine water instantly gives a red colour to the aqueous solu- tion of bicolorin. The colour changes to brown and then to yellow, and the variegating property is destroyed. But alkalies again restore the variegating property. Bicolorin reddens litmus paper, and possesses the characters of a weak acid. When heated it melts into a dark brown liquid, giving out a thick white vapour, like that of burning sugar, and burns with a light coloured flame, leaving a bulky charcoal which may be burnt all away without leaving any residue. In a distilling heat it under- goes decomposition. Bicolorin was analyzed by M. Herrmann Troramsdorf, who obt.UT.vid* Carbon 51*70 or 8 atoms = or per cent 51*90 Hydrogen 4*97 or 4^ atoms = 0-5625 — — 4*86 Oxygon 4li"33 or 5 atoms zz 5 — 43-24 11*5625 100-00 • Aim. dor Pharmucie, xiv. 205. I liil 98 FIXED ACIDS. 511 B'TL 11 ly.'I IJ SECTION XXV. — OF CAFFEIC ACID. Coffee is the fruit of the cqffea Arabica, a low evergreen tree, a native of Arabia. It was unknown to the ancient Greeks and Ro- mans. The generally received opinion is, tiiat the use of its infu- sion as a drink originated in Ethiopia. But the practice of drinking it in Arabia was introduced from Persia by the Mufti of Aden, in the 15th century. In 1554, its use first began at Constantinoi)le, from whence it was gradually adopted in the western parts of Europe. At Marseilles it was begun in I(J44. At Paris it was nearly un- known till the arrival of the Turkish ambassador, Soliman Aga, in 1669. In 1672 the first coflfee-house was established in Paris by an Armenian named Pascal ; but meeting with little encouragement he went to London, where the beverage had been previously introduced in the year 1652, when Mr Edwards, a Turkey merchant, brought from that country a Greek servant, of the name of Pasqua, who understood the method of preparing coffee, and first sold it in Lon- don, in a house which he kept for that purpose in George Yard, Lombard Street.* The first attempt at a chemical examination of coffee was by Neumann, or more probably by Dr Lewis in 1759.t It was found that coffee by roasting lost one-fourth of its weight, fj-ths of the coffee were dissolved in water, and spirits dissolved a little more. The effect of distilling the decoction and tincture of coffee was tried. But the chemistry of vegetable bodies had at that time made so little progress, that it would be useless to give the results. In the year 1800, Herrmann, an apothecary at Magdeburg, made a comparative set of experiments on Levant and Martinique coffee.^ He treated the coffee with alcohol and with water, remarked the different quantities of each coffee dissolved by these liquids, and made some experiments on the matters extracted by them. But his experiments did not elicit any new facts of much importance. In 1802, Mr Chenevix made some experiments on coffee. § He digested unburnt coffee in water, filtered the liquid, and precipitated by means of chloride of tin. The precipitate was washed, diffused in water, and the tin separated by sulphuretted hydrogen. The filtered liquor being evaporated to dryness, left a yellow semitrans- parent matter, solul)le in water and alcohol, and striking a green with salts of iron. The taste was bitter, and he considered it as the bitter principle of coffee. In 1806, an elaborate memoir on coffee was published by Cadet, || in which he endeavoured to determine the constituents of coffee by analysis, and to ascertain the changes induced by roasting. In the same year a valuable set of experiments on coffee by M. Paysse was published by M. Parmentier.^f He showed iimong other im- * Woodville's Medical Botany, i. 183 ; and Houghton, Phil. Trans, xxi. 311. f Lewis's Neumann's Chemistry, p. 378. i Crell's Annalen, 1800, ii. 108 and 176. § Phil. Matr- xii. 350. II Ann. tic Chim. Iviii. 216. T Ibid. lix. 196. r.VFFEIO ACID. 99 green id it as ici. 311. 350. portant facts that the peculiar principle discovered by Chenevix in coti'ee was {in acid to which he gave the name of caffeic acid, and the properties of which he describes. In 1808, a new and elaborate analysis of coffee was published by Schrader.* Hut though his experiments were useful in clearing the way, he did not succeed in obtiiining any of the peculiar prin- ciples of coffee in a separate state. In 1821, Robiquet discovered a crystallizable substance in coffee, to which the name of caffein has been given, but which does not possess alkaline properties.! The properties of caffein were farther investigated by Pelletier.| In 1821, Runge and Garot§ pointed out an easy method of obtaining caffein, and showed also that coffee contained a peculiar acid, thus confirming the statement of Paysse.|| These statements were con- firmed, and the properties of caffeic acid described at some length by Pfaff.t To obtain caffeic acid, the precipitate by means of acetate of lead from the infusion of coffee is mixed with water, and the lead precipitated by sulphuretted hydrogen. The filtered liquid is eva- porated to the consistence of a syrup, and then mixed with its own bulk of alcohol. The portion held in solution by the alcohol is tanvo-coffeic acid, the portion thrown down caffeic acid. Caffeic acid is a white powdor insoluble in alcohol, but soluble in water. The aqueous solution has a slight colour. It reddens litmus paper. It is either not at all or only very slightly opalized by caustic ammonia, carbonate of potash, or soda, lime water, nitrated suboxide or oxide of mercury, or by acetate or diacetate of lead. But the first three of these substances give it a brown colour, while lime water colours it yellow. When mixed with perchloride of iron it does not become green, and with ammoniatcd copper it does not strike the green, which is so characteristic of malic acid. With barytes water it throws down a yellow precipitate, soluble in nitric acid, and with albumen a flocky precipitate, without any shade of green. The characteristic property of caffeic acid is this : — when strongly heated it emits a smell precisely similar to that of roasted coffee. According to the analysis of Professor Pfaff, its consti- tuents are Carbon 29-1 or 12 atoms =9 or per cent. 29-88 Hydrogen 6*9 or 17 atoms = 2-125 — — 7-06 Oxygen 64-0 or 19 atoms =19 — — G3-0(] 30-125 100-00 But no confidence can be put in this formula. Indeed, it is obvious from the description, that Pfaffs caffeic acid could not have been pure. Tanno-caffeic acid. It is obtained by evaporating the alcoholic solu- * N. Gelilin's Journal, vi. 544. f Jour, de Pharmacie. xii. 2:29 ; and Ann. de Chini. et de Pliys. xxiv. 183. X Ibid. xii. 2-29. $ Ibid. p. 234. || Materialien zur Phytologie, p. 146. T Sweigger's Jour. 1x1. 4»7, and ixii. 31 ; or Poggendorf's Annalen, xxiv. 376. 100 FIXED ACIDS. ! ! H 1 tion from wliicli the cafi'eic tickl was precipitated. It is a dark brown extractive substance, having a very acid and astringent taste, without the least flavour of bitterness or sweetness. In water it dissolves in all proportions, but is less soluble in absolute alcohol. The aqueous solution diluted till it has become colourless, assumes a fine emerald- green colour when mixed with nitrated peroxide of iron. When the solution is concentrated a dark-green precipitate ftills. By persul- phate of iron it is not at first altered ; but after some time it as- sumes a green colour, and at last a white precipitate falls. With ammonieted copper, it assumes first a pure pistacio-green colour, then a dark-green precipitate falls. When mixed with chloride of gold it is green by transmitted, and brown by reflected light, and at last a precipitate of metallic gold falls. With nitrate or sub- nitrate of mercury it throws down a precipitate, at first grey, but afterwards becoming flesh-red : with lime water an orange-yellow, and with barytes water a sulphur-yellow precipitate. By corrosive sublimate, tartar emetic, cand isinglass solution, it is not altered. By ammonia, potash, and soda, it is coloured reddish-brown ; by car- bonate of potash or soda, at first greenish, then reddish-brown which becomes a full green when exposed to the air. Albumen, by this acid, is thrown down in flocks, and the liquid, after a certain time, becomes grass-green. Sulphuric ether dissolves the greatest part of it, and the un- dissolved portion possesses all the above described characters, except the green colour of the albumen, which it does not produce. SECTION XXVI. — OF PICROTOXIN OR PICROTOXIC ACID. This is the substance to which the cocci/Iks indicns, the fruit of the menispermum coectilus owes its deleterious (lualities. Its nature and properties were investigated by Boullay in 1811.* He bestowed uj)on it the name of picrotoxin, from its bitter taste and its poisonous nature.f It may be obtained by the following process: Boil the berries in a sufficient quantity of water. Filter the decoction, and add to it acetate of lead as long as any precij)itate falls. Filter the liquid a second time, and evaporate it with caution to the consistence of an extract. Dissolve this extract in alcohol of the specific gravity 0'817. Evaporate this liquid to dryness. These alternate solu- tions and evaporations in water and alcohol must bo repeated till the dry residue is completely soluble both in water and alcohol. It is now picrotoxin united with a yellow colouring matter. Agitate it with a small (quantity of water. That liquid dissolves the colouring matter, which is very soluble, and occasions tin; separation of a great number of small crystals which constitute picrotoxin nearly pure. Wash them with a little water and then with alcohol. Picrotoxin thus prepared possesses the following properties : — It assumes different forms. INIost commonly it crystallizes in needles ; but some times it is in silky flexible filaments, in tran- * Ann, tie Cliitn. Ixxx. 209. f From rut^m, bitter, an(' ro^intt, jioison. yjwi -^. berries add to liquid ence of gravity e solu- till the It is tate it louring Iti great pure. otoxin CCS in tran- PICROTOXIC ACID. 101 sparent plates, in radiating and niamrniForm masses, or in hard granular crystals. To dissolve it, 25 times its weight of boiling water, and 150 times its weight of water, at the temjjerature of 57°, are requisite. Its taste is intensely bitter, and it does not alter the colour of litmus paper. No reagent is capable of precipitating it from its aqueous solu- tion. Alcohol of the specific gravity 0*8 10 dissolves one-third of its weight of it. Sulphuric ether of the specific gravity 0*7 dissolves two-fifths of its weight of it. It is insoluble in oils. M. Boullay, the discoverer of picrotoxin, considered it as a vege- table alkali, and several of the salts which it forms with acids, have been described. M. Casaseca* has endeavoured to prove, that it is incapable of neutralizing acids. But this alone is not sufficient to deprive it of its alkaline characters. Pellctier and Couerbe, in their new analysis of the seeds of the menispermum cocciilus,] turned their particular attention towards the question, whether picrotoxin was entitled to rank as an alkali. They decided in the negative, and consider it as approaching more nearly to the characters of an acid than a base. But when they attempted to unite it with the organic salifiable bases, they were un- able to obtain stable and definite compounds. They found that picrotoxin was incapable of depriving muriatic acid of the property which it has of reddening litmus pajjcr, or even of diminishing that property. Muriatic acid dissolves picrotoxin, and the solution yields beautiful crystals. But when these crystals are washetl with a sufficient quantity of water, the whole acid is washed off, and the ])icrotoxin is obtained pure and unaltered. Similar experiments were made with other acids, with the same results. When picrotoxin is dissolved in acetic acid, we also obtain crystals from the solution. But the whole acetic acid is washed off by cold water, and the picrotoxin is left pure and unal- tered. When picrotoxin and iodine are boiled in distilled water, the liquid becomes and remains acid, in si)ite of the presence of a great excess of picrotoxin. By repeated crvstallizations we obtain the picrotoxin perfectly pure from this solution, without any trace of iodine or hydriodic acid. The concetitrated acids destroy picrotoxin. Sulphuric acid, at the temperature of 57°, docs not seem to act at first. But gradually the picrotoxin becomes light yellow, and finally, saffron yellow. The slightest augmentation of temj)crature causes the destruction of the picrotoxin, which is charred. Nitric and hyponitrous acid transform picrotoxin to oxalic acid. From these and other similar facts, JMM. Pellctier and Couerbe conclude, that picrotoxin has not the property of combining with acids. They do not even facilitate its solution in water. * Jour. (Jo I'lianiiacio, xii. CD. f Ann. 'le Cliim. et de Pliys. liv. 181. !'fa Hr i ' 'it 1 ill' ;l 102 FIXED ACIDS. 1*1 I B ■a I il All the alkaline bodies, on the other hand, facilitate the solution of picrotoxin in water. With potash and soda we may dissolve a considerable quantity of it in water. If we add an acid to the solu- tion, the picrotoxin separates unaltered. We can, by washing, sepa- rate the alkaline liquid, and obtain the picrotoxin in a state of purity. But when we heat concentrated solutions of potash, soda, or ammonia containing picrotoxin, that substance undergoes a com- plete alteration, and is converted into an orange-yellow substance, soluble in the alkali. It may be thrown down by acids in the state of a brown powder. This substance possesses acid characters. But has not been much examined. Lime, strontian, barytes, and magnesia, unite to picrotoxin, and hinder it from crystallizing in prismatic needles. The crystolliza- tions of picrotoxin from the seeds of the menispermum in plates or grains, is owing to the presence of lime. Wlien an alkaline solution of picrotoxin is subjected to the action of the galvanic battery, the compound undergoes decomposition, and the picrotoxin attaches itself to the positive pole, while the potash goes to the negative jjole of the battery. The same result was ob- tained with solutions of picrotoxin in soda and ammonia. Pelletier and Couerbe attempted to combine picrotoxin with brucina. They boiled a mixture of 1 ])art of brucina, and 4 parts of picrotoxin in distilled water. The liquor was filtered while boiling hot. On cooling, it deposited a mass of flexible, dirty-white, silky crystals. Tliey were subjected to pressure and redissolved in boil- ing water. When the solution cooled, they appeared again with all their original characters. When they were dissolved in water and potash, or soda added, the brucina was precipitated, being recog- nised by the jjroperty which it has of striking a red with nitric acid. When subjected to the action of a galvanic battery, the picrotoxin crystallized round the positive pole, while the brucina crystallized round the negative ])ole. They succeeded equally in forming and in decomposing by the galvanic battery, ))recisely with the same phenomena, picrotoxates of strychnina, quinina, and cinchonina. They found that picrotoxin was rendered less soluble by inorphina than by any other of the vegetable alkalies. This seems to show, that the alkalinity of mor- phina is very feeble. But it accpiires a greater degree of solubility than when per se, as the solution is precipitated by ammonia, and decomposed by the galvanic battery with the usual jihenoniena. Nar- cotina is the weakest of all the alkalies, yet it acquires an increase of solubility by the action of ])icrotoxin, which appears to combine with it. The picorotoxate of narcotina is precipitated by ammonia, and decomposed by the galvanic battery. MM. Pelletier and Couerbe, determined the atomic weight of picrotoxin, by analyzing the picrotoxate of lead. They made two aniilyses. In the first, they found the salt composed of Picrotoxin ... 52 or 15" 16 Oxide of lead . . or 14 MECHLOIC ACID. 103 by tlie toxates otoxin of the " mor- ubility and Nar- croase iiiibine nonia. k In the second, of Picrotoxin . . . 55 or 17*11 Oxide of lead . . 45 or 14 By the first of these analyses, the atomic weight is 15" 16, by the second, 17*14. They analyzed picrotoxin by means of oxide of copper, and the same analysis was made by Oppermann. They obtained Carbon Hydrogen Oxygen Pellcticr and. Couerbe. 60-91 6-00 33*09 These numbers lead to t Oppermann. 60-09 6-11 33-89 100^ 100-00 le following atomic constitution :- 1 2 atoms carbon =9 or per cent. 60-5 1 7 atoms hydrogen = 0-875 — — 5-88 5 atoms oxygen =5 — — 33-6 1 14-875 100-00 But this analysis is not satisfactory, because Pelletier and Couerbe have not given the data from which their atomic quantities were de- duced. SECTION XXVII. — OF MECHLOIC ACID. This acid was discovered by M. Couerbe, and was shortly described by him in a paper, read before the Academy of Sciences of Paris, in July, 1835.t If a current of chlorine be made to pass over meconin in fusion, it is absorbed, and the meconin becomes first red and then deep yellow. Two new substances are formed ; the one white and crys- tallizable, is mechloic acid ; the other has a resinous aspect, con- tains a great deal of chlorine, and may be sepai'ated by boiling the product with carbonate of soda. To purify the mechloic acid, it must be dissolved in potash, and precipitated by nitric acid. It is then white, and crystallized in beautiful prismatic needles, soluble in boiling water, but very sparingly in cold water. It is little soluble in alcohol and ether. Its taste is acrid and acid. It melts v. !ien heated to 257", and is volatilized at a temperature between 374° and 378°. When thrown upon red hot coals, it gives out a white smoke without flame, ac- companied by an odour analogous to that of jessamine. It is, when in the state of chloride, composed, according to Couerbe, of Chlorine . . . 5-43 or 4*5 Organic matter . 94-57 or 78-37 100-00 When dissolved in alcohol and digested with oxide of silver, the * Aim. dcr Pharin. x. 205. \ Ann. de Cliini. et de Phys. lix. 148. n u « 104 FIXED ACIDS. chlorine is separated. If wo filter and evaporate tlio solution, we obtain a white, pearly substance in scales, which dissolves in ctlicM-, and crystallizes in very short four-sided square prisms. It melts at 320°, and is volatilized at 321)". It reddens litmus paper, and precipitates the soluble salts of lead and copper ; but not those of silver, iron, lime, and mercury. Sulphuric and muriatic acid do not alter it ; nitric acid destroys it, but without changing it into oxalic acid. It is soluble in boiling alcohol, and ether and water, and crystal- lizes when the solutions cool.* Couerbe subjected mechloic acid to analysis, 100 parts yielded 178*66 of carbonic acid, and 36*66 of water. Hence (as it contains no azote), the constituents must be Carbon 48*727 or 14 atoms = 10*5 or per cent. Hydrogen 4*073 or 7 atoms = 0*87') — — Oxygen 47*200 or 10 atoms = 10*000 49*12 4*09 47*79 loot 21*375 100-00 If the chloride of mech;o'C acid, the analysis of which is given in last page, be a neutral compound, mechloic acid has an atomic weight of 78*37. To obtain this weight, it would be necessary to multiply the preceding numbers by 3|. This would give us 51^ atoms carbon . . = 38*;'5 25J atoms hydrogen . . = 3*2 36| atoms oxygen . . = 36*6 or probably (to get rid of fractions) of f; 1 .. i t 5 1 atoms carbon 26 atoms hydrogen 37 atoms oxygen 78*3 = 38*25 = 3*25 = 37*00 78*5 .1 u making the atomic weight 78*5. :! il SECTION XXVIII. — OF AMYGDALIC ACID. This acid was discovered by M. Winckler some years ago, and noticed by him in a paper which he published on tlie oil of bitter almonds-l In the year 1836 he published, in the same journal, a detailed description of the mode of preparing this acid, and an ac- count of its properties. § His mode of pieparing it is the following: — 80 ounces of bitter almonds, freed by pressure as much as possible from the fixed oil whicl) they contain, were mixed with 90 lbs. of water, and put into a distilling apparatus and 160 ounces of the water distilled oft". This portion was put into a smaller still and 80 ounces of it distilled * Ann, (!e Cliim. ft dc Pliys, I. r,:>\. f Ibid. lix. 149. X Liehig'? Aniialen der Fharinacie, w, 24-2. § Ibid, xviii. ;310. but: and AMYGDALIC ACID. 105 ac- ofF. This portion was well agitated in order to mix the volatile oil that had come over with the water, and then 4 ounces of pure mu- riatic acul, of the specific gravity 1'12 were added, and this mixture was evaporated to dryness in a porcelain dish over the water-hath, taking care to dissipate the whole of the muriatic acid. By this pro- cess 330 grains of a yellowish-white imperfectly crystallized matter was obtained. When digested in ether it all dissolved except 90 grains of sal ammoniac. The ether being left to spontaneous crys- tallization a light yellowish crystalline matter was obtained, having a very sour taste, and reddening litmus paper. Being dissolved in water, and treated with animal charcoal and again crystallized, it was obtained quite colourless, and, in this state, was considered as pure amygdalic acid. It appears from this mode of preparation that by the addition of muriatic acid to the oil of bitter almonds and sub- sequent evaporation, almost the whole of this oil is converted into amygdalic acid and ammonia. Wohler and Liebig have since found that amygdalic acid is easily obtained from amygdalin. If we dissolve amygdalin in cold barytes water no decomposition takes place. But if the solution is raised to the boiling temperature (though air be excluded) ammonia is disen- gaged. When air is admitted carbonic acid is disengaged, and a little barytes precipitated. If wc boil the solution for a quarter of an hour the decomposition is completed, and all indications of am- monia disappear. A current of carbonic acid passed through the hot liquid throws down the uncombined barytes, and leaves a solu- tion of pure amygdalate of barytes.* Amygdalic acid thus obtained, has a slight tendency to crystallize, and the crystals constitute usually transparent plates or scales. Its taste is acid, styptic and peculiar. Its smell is faint, but has some resemblance to that of sweet almonds. When heated in a platinum spoon, it gives out water and speedily melts into a yellowish-white liquid, having the consistence of oil, and which, on cooling, con- cretes into a translucent gummy-looking mass. When the heat is in- creased the acid flies off^ in a white smoke, havinj? a smell resembling hawthorn blossom, while a bulky coal remains behind. When this smoke is brought in contact with flame, it catches Are and burns with a red flame. Amygdalic acid is obtained easily by precipitating the barytes from tlie amygdalate of barytes by sulphuric acid. It is a slightly acid liquid, which, over the water-bath, dries into a gummy mass. When the solution is left for some time in a warm place, v/e ob- serve marks of crystallization. It is very deliquescent. It is insolu- ble in absolute alcohol and in ether, and but little soluble in spirit of wine. When boiled with binoxide of manganese it undergoes no change; but if we add sulphuric acid we obtain formic acid, carbonic acid, and oil of bitter almonds. * Ann. (le Chiin. ct de Pliys. Ixiv. 19,>. I II I 106 FIXEU ACIDS. IP II' I m When heated in a retort it allows the temperature to he raised pretty high hefore it begins to be decomposed, it becoines brown by degrees, and, when the heat is raised it distils over in a dark red- dish-brown, resinous-looking matter, which is very slightly soluble in water, but readily soluble in alkaline ley and in alcohol. Neither sulphuric nor nitric acid occasion any alteration in the colour of amygdalic acid at the ordinary temperature of the atmo- sphere. Wiihlcr and Liebig analyzed amygdalate of barytes, which they obtained by boiling a solution of amygdalin in barytes water. They could not crystallize this salt. But obtained it in a gummy mass, which may be heated to 374° without decomposition. It becomes white, has the aspect of porcelain, and is easily reduced to powder. 100 parts of the anhydrous salt were composed of Amygdalic acid . . 85'9 or 57*87 Barytes . . . 14*1 or 9*5 100-0 Making the atomic v/eight of the acid 57"87. The salt being analyzed by oxide of copper gave Carbon 44".38 or 40 atoms = 30 or per cent. 44*94 Hydrogen 5*28 or 26 atoms = 3*25 — — 4*86 Oxygen 36*24 or 24 atoms =24 _ _ 35*99 Barytes 14*10 or 1 atom = 9*5 — — 14*21 66*75 100*00 It is obvious that amygdalic acid is C"*" H^*' O** ; that is to say, it is amygdalin combined with two additional atoms of oxygen and deprived of an atom of azote. Hence its atomicweight must be 57*25 or rather more than I per cent, lighter than the number resulting from the analysis of amygdalate of barytes. It forms neutral salts with the bases and disengages carbonic acid from the alkaline and earthy carbonates. The amygdalates, in general, crystallize readily, though some, as amygdalates of potash and ammonia, show no tendency to assume a crystalline form. 1 . Amygdalale of potash. It may be obtained by digesting solu- tions of amygdalic acid and carbonate of potash. To obtain the salt in a neutral state the best way is to evaporate to dryness and digest the dry mass in alcohol. That liquicl dissolves the neutral portion, while the excess of carl)onate of potash remains behind. On evaporating the alcoholic solution, the amygdalate of potash re- mains behind similar in appearance to soap. It dissolves readily both in water and alcohol. The solution is neutral, its taste is mild and scarcely saline. When heated, it be- haves very similar to amygdalic acid. 2. Amygdalate of ammonia. This salt may be obtained by mix- ing a solution of amygdalic acid with a slight excess of ammonia, and evaporating till that excess is driven ott". The salt is a yellowish-white soft mass, having a mild taste, and TANNIC ACID. 107 00 to say, behavinfj, when heated, hkc amygdalic acid It is sohible in water and in alculio]. 3. Ainyg(htlate of harytcs. Obtained by digestin^r a sohition of amygdalic acid over carbonate of barytes. It crystallizes readily, when the sohition is evaporated in short, fine prisms. It is much less soluble in water than amyfrdalates of potasii or ammonia. It behaves, when heated, as amygdalate of potash does. 20 parts of amygdalie acid, dried at 8()°, decomposed 13-38 parts of carbonate of barytes. A small portion of carbonate of barytes which passes into the solution, precipitates when the liquid is heated. 4. Amygdalate of silver. This salt is easily obtained by mixing together solutions of camygdalate of ammonia and nitrate of silver. It falls down in the state of a heavy, white crystalline powder, which is very easily washed. It must be dried in a gentle heat, and where it is excluded from the action of the light. When boiled in water, and the solution filtered wh"'e hot, it is deposited on cooling in pretty large crystals, very similar to those of benzoic acid, only having a slight yellow colour. When heated it melts into a dark-coloured mass, and when the temperature is raised it undergoes decomposition, behaving in the way that amygdalic acid does under the same circumstances, and leaving pure metallic silver behind. This salt, according to the analysis of M. Winckler, is composed of Amvffdalic acid 54*03 or 52*38 or I atom Oxide of silver 45*37 or 14*5 X 3 or 3 atoms 100*00 of M. Liebig analyzed amygdalate of copper, and found it composed Amygdalic acid Oxide of copper 53*025 5X3 or 1 atom or 3 atoms lition IS it be- ly mix- iionia, and 22*875 When a solution of amygdalic acid is heated with binoxide of manganese, carbonic acid is given off, and oil of bitter almonds dis- tils over, which by the action of the air is converted into benzoic acid. When amygdiilic acid is boiled with fuming nitric acid, the formic acid is entirely decomposed, and if we continue the heat till no more acid fumes are observed, and then add Vtater, colourless crystals of benzoic acid are deposited. SECTION XXIX. — or TANNIN, OR TANNIC ACID. Nutgalls are excrescences that grow upon certain species of oak, particularly the qiiercus inftcioria and the qnercus ccrris. They are produced by the puncture of the female of the Cynips gallcc tine- torice, or of the cynips (jitcrcus folii, hymeno})terous insects, which deposit their ova in the puncture. The nutgall gradually fcrms round the ovum. It is a hard spherical body, varying in size from III ■iV; ■I .'li i 108 FIXKU ACIDS. 1 ill * j : I' I t 1^ BUI > m 111 ^ f ll u quurtor of un inch to a whole inch in lUametor. The best gall- nuts coine from the Lovatit. (Jalluiits (in Latin, (tal/re) were known to the ancients, and were employed l>y them in medicine. Hut. they seem to have had no accurate idea of their origin, as they considered them to he the fruit of the oak. Though nulgalls had, for a long time, been employed in medicine, and thougli tliey were an essential ingredient in the black dye, and in the manufacture of ink, yet the lirst attempt to investigate their nature was by Dr Lewis, about the middle of the last century, during a set of experiments undertaken to ascertain the best method of making ink.* lie detected in them a substance which strikes a b/ac/t colourf with solutions of iron, and comfit fates with isinglass.^ Hut chemistry, in his time, had not advanced far enough to enable him to investigate, or to obtain this substance in a separate state. Deyeux was perhaps the first chemist who attempted to procure tannin in a sej)arate state. lie pointeil it out as a ))eculiar jcshtous sul)- stance ; but without assigning it a name.§ Nothing could be more inaccurate than his classing it with the resins, to which it bears no resemblance whatever. Sequin, soon after the commencement of the French Revolution, engaged in a series of ex})eriments on tlu; art of tanning leather ;|| during which, he discovered that tannin has the property of precipitating glue, from its solution in water, anil of combining with the skins of animals. This led him to consider it as the essential constituent of the substances em])loyed for the pur- pose of tanning skins. , I lence the name tannin and tanning principle, by which it was distinguished by the French chemists. Proust was the tirst chemist who attempted to procure it in iv separate state, and to investigate its properties.^ Consideral,\ light was thrown upon the constitution of astringent substances, and on their operation in tanning, by Sir H. Davy.** The number of ex- perimenters npon nutgalls, and the methods proposed for extracting tannin from them in a state of purity, made during the course of the present century, is so great, that a bare enumeration of them would occupy a considerable space. And as very little light was thrown upon the nature of nutgalls by all these experimenters, numerous as they were, it seems unnecessary to enter into any further historical details. In the year 1834, an exceedingly simple process for extracting tannin from nutgalls, in a state of purity, was discovered by IVI. Pelouze. This enabled him to ascertain its properties, and investi- gate its composition.tt And his experiments were speedily repeated and contirraed by M. Licbig.JJ * Philosophical Commerce of the Arts, p. 377. f ^^"^' P* ''^^^^^• I Ibid. p. 3S7. $ Ann. de Chim. xvii. 23. ; ibid. xx. 38. \ Ibid. XXV. 225— XXXV. 32, and xlii. 89. ** Piiil. Trans., 1803, p. 233, and Jonr, of the Uoyal Institntlon, vol. ii. f f Ann. de Chiin. el do Phys. liv. 337. XX Ibid. Ivii. 417, and Annalt'u dor PInirniacio, x. 172. of the would thrown •ous as orical [•acting by M. nvesti- poatoJ 310. xx. 38. ii. TANNIC ACID. 109 Tannin may he obtained pure from nuty muriatic, nitric, jiliosphoric, and arsenic acids ; hut not hy oxalic, tartaric, lactic, acetic, citric, succinic, or selenious acid. Neither does sul|tluu"ous acid iras j)roduce any j)recij)itate. When nitric acid is heated with tainiin it deconinoses it rujjidly, red vapours are izivcn olf ahtmdantly, and oxalic acid is formed and de|)osited in crystals. Salts of cinclionina, quinina, hrncina, strych- ninu, codeiua, narcotimi, and niorjduna, form with solution of tannin white precipitates, very little soluble in water ; but very soluble in acetic acid. When tannin is poured into a solution of <;elatin in excess, a white opaque i)reci|)itate falls, which is soluble (especially wiieu heated) in the liquid remainin«f. Hut when there is an excess of tannin in the liquid, the precipitate, instead of dissolvinj^ when heated, col- lects into a yrey-coloured and very elastic membrane. In both cases the filtered liquor strikes a blue with the persalts of iron. M. Pelou/e adopted the following method, to determine whether tannin contains any gallic acid. A j)iece of skin depilated by lime, as is usual, when it is ])rej)ared for being tanned, is put into the solu- tion of tannin, and agitated with it from time to tinu'. The rHpiid is then filtered. Tiie whole of the tannin is absorbed by the skin, and the filtered li(|uid, if no gallic acid be present, does not strike a blue with the persalts of iron. Hut if any gallic acid be ])resent, though it amount only to one thousandth part, it gives a very per- ceptible shade of blue. When alumina in the state of jelly is agitated with a solution of tannin, it absorbs it ra])i(lly, and forms w'.th it a very insoluble com- pound. For when the liquid in which the alumina has been agi- tated is filtered, it no longer strikes a blue with the persalts of iron. M. Pelouze dried tannin in a temperature of 248°, and then sub- jected it to an ultimate analysis by means of oxide of copper. Liebig analyzed it in the same way. The results obtained are the ft )llowing : Ptlouzc ] Mebiff. Carbon •OO-Dl i 51-79 Hydrogen 4- it) 1 4-12 Oxygen 44-1)3 4i-09 100-00* loot To determine the atomic weight of tannin, a quantity of tannate of lead, obtained by pouring acetate or nitrate of lead into an excess of tannin was washed and dried at the temperature of 248° and ana- lyzed by combustion. Liebig obtained * Ann. (le Cliiiii. ct cle Plivs. liv. 343. flbui. Ivii. 417. f ;i ^-^ TANNIC! A(Mn. Ill thy ciu. Tftn»in ( )\"ulo of loiul i]rr\) or 27'0:. :i4-l or 14 l(H)-() This jjives us '27 for tbe utoniic weii,'lit of tiiimiii. Now, M. Pelouze coiiiiidcra IH atoiiiH carlxin = 13-r) or per coiit. r>()'7l 1) atoms liv(ln»;,'on = l-l'Ih — — 4-2*2 1'2 utoinsoxviicii = l*2'0 — — 4rv(>7 •2(i'<)2ri 100- 00 {»roportions sufRoleiitlv near his analysis und tiio atomic weight found »y him. Liehi<]r« "" ^''^ contrary, considers the following atomic constitu- tion as approHchiiig ncann* the truth : — 18 atoms carbon = i;j'5 or per cent. 50'9.^ H ntoms hydrogen =1 — — 3*77 12 atoms oxygen =12 — — 4;>28 2G-5 100-00 The difference between these two determinations being only an atom of hydrogen, antl Pelou/e's nuud)ers exceeding the hydrogen found, while Liebig's falls short of it, this circumstance weighs in favour of Liebig's view. The peroxide of iron was cond)ined with tannin by M. Pelouze, by pouring persulphate of iron into a solution of tamiin, washing the precipitate and drying it at 248". 1073 parts of this salt were found tc contain 1 29 parts of peroxide of iron. Hence it was composed of Tannin .... 3(3-58 Peroxide of iron ... 5 41-58 Now, if an atom of tannin weighs 2G-5, it is obvious that this salt must be a sesquitannate of peroxide of iron. For sesquitannate would consist of 1^ atom tannin . . . =39*75 1 atom peroxide of iron . = 5 44-75 It is this sesquitannate which constitutes the basis of common ink. For the recent infusion of nutgalls contains very little gallic acid ; und the gallate of peroxide of iron is rapidly decomposed when boiled in water. The tannate of protoxide of antimony is a white gelatinous preci- pitate, very insoluble in water. It is also a sesquitannate composed of 1,} atom tannin 1 atom protoxide of antimony 39-75 9*5 49*25 [if 1 iil \m 11' 112 FIXED ACIDS. According to Berzelius, tannate of potash and tannate of amnionia are very little soluble in water. They precipitate under the form of a white earth. They dissolve in boiling water, and partly pre- cipitate as the liquid cools. When these precipitates are washed and dried, they have the appearance of a white earth, and are not altered by exposure to the atmosphere. But when they are kv. ;/t moist, extractive is formed by the absorption of oxygen from the air. The tannate of soda has the same appearance but it is much more soluble.* When a very dilute aqueous solution of tannin is exposed to the air, it gradually loses its transparency, and lets fall a grey precipi- tate in crystals consisting almost entirely of gallic acid. To obtain that acid in a state of purity, we have only to treat the boiling solu- tion with a little animal charcoal. If we put the solution in a graduated glass tube in contact with oxygen gas, we shall tind that the gas is gradually absorbed and replaced by an equal volume of carbonic acid gas, while after some weeks numerous crystalline needles of colourless gallic acid may be seen traversing the liquid. If oxygen have not access to the solution of tannin, it may be kept a long time without undergoing any alteration. The same remark applies to the infusion of nutgalls. Chevreul kept it in a well-corked bottle for 3 years without any alteration. Nutgalls give out to water about half their weight of soluble matter ; about 40 per cent, of which is tannin. The gallic acid contained in the solution amounts only according to Kichter to 3| per cent, of the weight of the nutgalls. Yet we know that when infusion of nutgalls is left to spontaneous decomposition, it yields about ^th part of the weight of the galls of gallic acid. Hence it is obvious that the greater part of this acid formed during the spon- taneous decomposition of infusion of nutgalls, is at the expense of the tannin. It is well known to chemists that the only way of getting gallic acid in considerable quantity from infusion of nutgalls, is to leave the infusion covered with paper to spontaneous decom- position. SECTION XXX. — OF CATECHUIC ACID. Catechu {cachou in French) has been an article of the Materia Medico for above a century. It is imported from India, and was at first distinguished by the name of terra Japonica, because it was considered as n earth, which was found in Japan. This opinion, stated by Pomet on the authority of Dr Caen, was so inconsistent with the characters of the substance that it fell under general dis- credit. And it came to be believed that catechu was extracted from the juice of a nut (areca, or betel nut). And agreeably to this opinion, Linnaeus, in both editions of his Materia Medica, refers it to tlie areca catechu. The first accurate information upon the manufacture (>f catechu, was obtained from a paper published by Ann. (le Ciiim. et tie Plivs. xxxvii. 389. CATECHUTC ACIU. 113 Ipinion, isistent ral dis- tracted [ably to refers Ion the lied by Mr Ker, entitled " Description of the plant from which the terra Japonica is extracted."* This gentleman, at that time assistant- surgeon to the civil hospital at Bengal, not only attended carefully to the process of the manufacturer, but actually repeated it himself. The tree yielding catechu is the Mimosa catechu of Linnaeus ; the acacia catechu of modern botanists. It grows plentifully in the mountains of Kanhanna in Hindostan, and flowers in June. It seldom exceeds 1 2 feet in height, and 1 foot in the diameter of the stem. The catechu is obtained from the interior brown wood of the tree. After felling the trees, the manufacturer carefully cuts off the exterior white part of ihe wood. The interior coloured wood is cut into chips with which he tills a narrow mouthed unglazed earthen pot, pouring water upon them till he sees it among the upper chips. When this is half evaporated by boiling, the decoction without straining is poured into a flat earthen pot, and boiled to one third part. This is set in a cool place for one day, and after- wards evaporated by the heat of the sun, stirring it several times a-day. When it is reduced to a considerable thickness, it is spread upon a mat or cloth, which has previously been covered with the ashes of cow-dung. This mass is divided into quadrangular pieces by a string, and completely dried by turning them frequently in the sun till they are lit for sale. This extract is called cutt by the natives. The term catechu is said to be a compound of the word cate, a tree, and chu, juice. Catechu is used in India as a masticatory, it is employed also for tanning leather, and it constitutes an important dye-stuff. Con- siderable quantities of it are consumed in this country by the calico printers. Two kinds of catechu come to this country ; one from Bombay, the other from Bengal. They differ from each other more in their external appearance, than in their chemical composition — that from Bombay has a uniform texture, and a red brown colour, and its specific gravity is generally about 1'39. What comes from Bengal is generally more friable and less consistent. Its colour externally is like chocolate, but when broken it presents streaks of chocolate and reddish brown. Its specific gravity is about 1-28. The taste of both is the same ; being astringent, and leaving in the mouth a sen- sation of sweetness. They are not altered by exposure to the air.f Davy found the two varieties composed of Tannin Peculiar extractive matter Mucilage Insoluble matter, chiefly sai an( lime Bombay. Bengal. 54-5 48-5 34-0 36-5 6-5 8-0 • 5-0 T-0 100 100-01 I ;H \m V \ „ ' ' '■' fl * Med. Obs. and Inquiries, v. 15 1, f Davy, Piiii. Trans. 1803, p. 232. \ Ibid. 2,59. ' ' l! •H u ,1 If < 'I I ill I 114 FIXED ACIDS. The tannin struck a black with the pcrsalts of iron, while the extractive with the same salts gave a grass-green colour. Buchner, in the year 1834, discovered tlie existence of an acid in catechu, to which he gavethe name of tannic ncid{tanningensaure). But that name having been already given to the substance usually denominated tannin, Buchner's name was changed into catechuic acid. In 1835 some experiments on the mode of obtaining this acid in a state of purity, were made by Dahlstrom, an account of whicli has been given by Berzelius in his Jahrshericht, No. 14, p. 235. In the year 183(5, a set of experiments on this acid was published by Mr L. F. Svanberg, in the Memoirs of the Stockholm Academy of Sciences.* Buchner employed the following method to procure catechuic acid. Eight ounces of Bombay catechu (Bengal catechu is not so productive) were reduced to a very fine powder, and macerated during eight days in four times their weight of water, taking care to agitate frequently during the whole time that the maceration continued. The solution, after being left four or five days to become clear, was drawn off. The undissolved residue was treated as before with four times its weight of cold water. This process was repeated three or four times more, employing only twice the weight of the powder of water instead of four times. The undissolved residue was finally dissolved in eight times its weight of boiling water. The boiling hot solution containing the catechuic acid and the tannin was treated while boiling hot with a very dilute solution of acetate of lead, till the liquid (a little being filtered on purpose) has only the colour of Rhinewine, a proof that the colouring matter has been thrown down. The liquid is now filtered while boiling hot as rapidly as possible, because the acid begins to be deposited as soon as the liquid cools. At the temperature of 32° it is deposited immediately ; but at the summer temperature, some hours elapse before it begins to appear. The acid is deposited in the state of small white grains. After 12 hours it is collected on the filter, dis- solved ir boiling water, clarified by white of egg, and filtei'ed while boiling hot into a flask that can be shut so as to be air tight, because the acid becomes coloured when exposed to the air. When the liquid has been filtered the flask is to be filled with water, corked up, slowly heated, and then allowed to cool slowly. The acid is deposited during the cooling. As the catechuic acid obtained in this way was still impure, Svanberg dissolved it in hot water and precipitated it completely by acetate of lead. The catechuate of lead thus obtained was decom- posed by sulphuretted hydrogen. The catechuic acid was separated from the sulphuret of lead by hot water, and thus the whole of the colouring matter was left behind. When the solution cooled, the catechuic acid was deposited perfectly white. But if it be exposed while moist to the air, or if we attempt to wash it on the filter, it • Sec a translation of tlie paper in Pog'Sfiiulorf's Annalen, xxxix. IGl. lile tlic an acid isiiio'e). usually itccluiic .liis acid >f which p. 235. Liblished xdemy of atcchuic s not so acerated :ing care iceration [) become eated as icess was le weight dissolved if boiling acid and 3 solution purpose) g matter iling hot psited as ieposited rs elapse state of liter, dis- ced while because hen the ', corked acid is impure, [ctely by decom- 3parated |e of the [)led, the lexposed Ifilter, it Ici. CATECHDIC ACID. 115 i becomes yellow. It must therefoi ' be rapidly squeezed between folds of paper, and dried, in vacuo, over sulphuric acid. The water employed to dissolve it from the siilphuret of lead, must not be boiling hot, and it must not be employed in so small quantity as to become completely saturated ; for in both cases a portion of the colouring matter is again redissolvcd. This is prevented by apply- ing the water in sufficient quantity, and at a tempei'ature not exceeding 194°. Catechuic acid is very feeble, not stronger in its acid properties than common sugar. When boiled with carbonate of Hme, it does not expel the carbonic acid. When it is dissolved in carbonate of potash no carbonic acid is disengaged, until the acid has been added in sjch qiicintity that a portion of it crystallizes on the cooling of the liquid.* When catechuic acid is put into a glass vessel filled with ammonia- cal gas, that gas is absorbed, and the acid combines with it ; but the union is so slight that the whole gas makes its escape if we put the salt into a vacuum, or if we apply heat. If we dissolv(« in cold water catechuic acid, combined with ammonia, after the alkali has been expelled by placing it in vacuo, the catechuic acid almost im- mediately resumes its former state, and falls to the bottom under the form of a white powder. If we allow the access of air to the compound of catechuic acid and an alkali, oxygen gas is absorbed, and the acid becomes red, and at last black. Catechuic acid is not precipitated by gelatin. Acetate of lime gives with it a white precipitate, which is not soluble even in hot water ; but like all the compounds of this acid it becomes coloured when exposed to the air. Acet.itoof barytcs is neither precipitated by catechuic acid, nor by its compound with ammonia. Acetate of copper is not precipi- tated by the uncombined acid ; but the solution becomes brown and seems to be brought into the same state as when treated with caustic potash with access of air. If ammonia be added to the acid liquid, a dark brown precipitate falls. When acetate of copper is mixed with a hot solution of catechuic acid, a brown precipitate falls, which soon becomes black. Nitrate of silver is not precipitated by catechuic acid. But if a very little ammonia be added a black precipitate falls. Hot solution of catechuic acid throws down the same precipitate — it is redissolved in dilute nitric acid, and in caustic ammonia. Potash-chloride of gold is precipitated of a reddish brown colour by catechuic acid. The precipitate dissolves with a fine yellow colour when more water is added. When the mixture is heated, the gold is reduced and falls down light coloured. Soda-chloride of platinum is not precipitated by this acid ; but the solution becomes * The experiment must, be made out of the contact of air, othcrvvisi; the acid nil! be chaiijrpd into japonic acid. The best method is to fill the vessel containing the liquid \Yitli hydrogen {^as. I li \\ I I":. 116 FIXED ACIUS. iiiiii M V h\ yellow, and when heated the platinum is reduced, though slowly, and a small flocky brown matter falls down along with it. Acetate of lead is thrown down white by catechuic acid. The precipitate is dissolved completely when we attempt to wash it on the filter. By exposure to the air it becomes speedily yellow. To prevent this it must be rapidly dried between folds of blotting paper, and then placed in a vacuum over sulphuric acid. This salt was analyzed by M. Svanberg, and found composed of Catechuic acid . . 2316 or 16"91 Oxide of lead . . 1917 or 14 4233 This makes the atomic weight of catechuic acid 16*91, or very nearly 17. He analyzed the acid by heating it with oxide of copper, and found the constituents to be Carbon 61*666 or 15 atoms = 11*25 or per cent. 62*50 Hydrogen 4*720 or 6 atoms = 0*75 — — 4*16 Oxygen 33*614 or 6 atoms = 6-00 — — 33*34 18 100*00 But the atomic weight in this case is too high. The reason, doubt- less, is, that the catechuic acid, in the state in which it was analyzed by Svanberg, contained an atom of water. The anhydrous acid is, doubtless, composed of 15 atoms carbon . . =11*25 5 atoms hydrogen . . = 0*625 5 atoms oxygen . . =5 16*875 The true atomic weight is 16*875, a number almost coinciding with that derived from the analysis of catechuate of lead. SECTION XXXI. — OF JAPONIC ACID.* When catechuic acid is digested with caustic potash, in contact with the air, it absorbs oxygen gas, and the colour changes first to rose red, then to deep red, and finally to black. The same altera- tion takes place when ammonia is substituted for potash. By this absorption of oxygen, the catechuic acid is changed into japonic acid. Svanberg digested catechuic acid for several days in an excess of caustic potash, assisted by heat, taking care that the air had free admission. The alkaline liquor was now treated with an excess of acetic acid, evaporated almost to dryness, and digested in alcohol. The acetate of potash vas dissolved, and a superjaponate of potash remained behind. To purify this last salt completely, it must be repeatedly digested in alcohol. It is then to be dissolved in water, and muriatic acid added in the smallest possible excess. The japo- nic acid precipitates, only a very small portion of it remaining in * I'ojrgendorf's Annalen, xxxix. 171. J. ;h slowly, ;id. The rash it on low. To ing paper, is salt was 1, or very lopper, and , 62-50 4-16 , 33-34 100-00 ason, doubt- ?as analyzed rous acid is, [neiding with .1, in contact pges first to [same altera- [sh. By this I japonic acid, an excess of I air had free an excess of [d in alcohol. ate of potash f, it must be ired in water, . The japo- Iremaiuing in TAPONIC ACID. 117 solution. The greater the excess of muriatic acid, the greater quantity of japonic acid will be dissolved. Japonic acid is black, and dissolves very slightly in cold water — almost not at all, indeed, if it has been well dried. When fresh prepared, and still moist, it dissolves better in hot water, and, as the solution cools, the acid is deposited in black grains. Its aqueous solution reddens litmus paper. It is insoluble in alcohol. Acetic acid does not throw it down from its solutions ; but when japonate of potash is digested with an excess of acetic acid, and the whole evaporated to dryness, a superjaponate of potash is obtained. The japonates do not crystallize, but dry into hard masses. We obtain neutral japonate of potash when we boil the acid in a very concentrated state with caustic potash, and then remove the excess of potash by alcohol. It gives, with chlorides of barium, calcium aluminum, glucinum, and yttrium, bulky black precipitates, not soluble in dilute nitric acid. With sulphate of copper, it gives a very dark green precipitate ; with nitrate of silver, a black ; but it whitens when washed with water, in which it is somewhat soluble. After being dried at 2 1 2°, it is not decomposed by muriatic acid ; but caustic potash dissolves the acid, and leaves the oxide of silver. Svanberg analyzed japonate of silver, and found it composed of Japonic acid . . 4757 or 13-49 Oxide of silver . . 5112 or 14*5 9869 According to this analysis, the atomic weight of japonic acid is 13-49. He analyzed the acid by means of oxide of copper and obtained Carbon 61*34 or 12 atoms = 9 or per cent. 61-54 Hydrogen 4-25 or 5 atoms = 0-625 — — 4-27 Oxvffen 34-41 or 5 atoms = 5-0 — — 34-19 100-00 14-625 100-00 The atomic weight- is 14-625, or more than that resulting from the analysis of japonate of silver by 1-125, which is equivalent to an atom of water. Anhydrous japonic acid, therefore, is a compound of 1 2 atoms carbon . . . =9 4 atoms hydrogen . . = 0-5 . 4 atoms oxygen . . . =4 13-5 When we compare catechuic acid with japonic acid, we find the diflference as follows : — Catechuic acid . . C'» H'^ O'* Japonic acid . . . C'^ H* O* C^' H O This is equivalent to an atom of water, and three atoms of carbon. i 118 FIXED ACIDS. From this it would appear, that the oxygen gas absorbed by the catechuic acid, when it is converted into japonic acid, unites with the carbon. Whether carbonic acid be formed has not been ascertained, but it is probable. In fact, the ratios between the atoms in both compounds is the same. Wc might consider the composition as identical, if it were not for the ditFerence of the atomic weights. SECTION XXXII. — OF UUBINIC ACID.* If we dissolve catechuic acid in carbonate of potash, and leave the solution exposed to the air without the application of heat, it becomes red, and dries into a hard, uncrystalline mass, which dissolves in water with great difficulty. In this state, it is a ruhinate of potash, mixed with a quantity of carbonate of potash. If we apply heat during the evaporation, the acid blackens, and the salt is converted into japonate of potash. The evaporation, when we wish to obtain rubinic acid, must be spontaneous, or conducted in vacuo, over sul- phuric acid. The rubinate of potash is to be reduced to a very fine powder, mixed with water, and well shaken, a long time being required before the water is saturated with the salt. The dissolved portion is filtered from the undissolved portion, and saturated with acetic acid, in order to convert the carbonate of potash into acetate. Care must be taken to add as small an excess of acetic acid as pos- sible, because it dissolves some of the rubinic acid. The solution must be rapidly filtered from the undissolved portion. For, if air be admitted, the rubinic is always converted into japonic acid. The solution being mixed with strong alcohol, the rubinate of potash pre- cipitates. To obtain it pure, it should be washed with alcohol. Rubinate of potash thus obtained, throws down the earthy and metallic salts of a red colour. The precipitates generally redis- solve during the washing, when they are freed from the excess of the precipitating salts. From Svanberg's experiments it does not ap- pear possible to obtain rubinic acid in a disengaged state. When a solution of rubinate of potash is mixed with muriatic acid, the acid which falls possesses the characters of japonic acid. M. Svanberg analyzed rubinate of silver, and found it composed of Rubinic acid . . 32'81 or 23'56 Oxide of silver . . 20*19 or 14*5 53-00 This makes its atomic weight 23*56. He analyzed a given quantity of rubinate of silver by means of oxide of copper, and found the acid composed of Carbon 58*20 or 18 atoms = 13*50 or per cent. 58*07 Hydrogen 3*41 or 6 atoms = 0*75 — — 3*22 Oxygen 38*39 or 9 atoms = 9*00 — — 38*71 \h I 100 23*25 * Foggcndorf's Annalcn, xxxix. 17 !• 100*00 LLMIC ACID. 119 e being iposed ins of If tli's analysis be accurate, rubiuic acid bears no analogy either to catechuic or japonic acids, as will be obvious from the following comparison : — Catechuic acid . . C U' O" J.'ponic acid . . . C'2 H* O* Rubinic acid . . . C'« H« O" SECTION XXXIII. — OF ULMIC ACID. In the account of this acid given in the Chemistry of Inorganic Bodies (vol. ii. p. 105), the analysis of it by M. P. BouUay is inserted. It has been since obtained by M. Malagutti, by boiling sugar in diluted acids. He analyzed it, dried in the temperature of 392°, and obtained Carbon .... 57*48 Hydrogen .... 4"76 Oxygen .... 37'36 100-00* Numbers approaching nearly those of Boullay. M. Malagutti analyzed ulmate of silver, and obtained Ulmicacid . . . 74 or 41-27 Oxide of silver . . 26 or 14-5 100 Uljnate of copper was composed of Ulmic acid . . 89*2 or 41-29 Oxide of copper . . 10-8 or 5 If the salt be neutral, those numbers give us 41*28 for the atomic weight of ulmic scid. This deviates but little from Boullay 's pre- vious analysis of ulmate of copper. If we adopt Malagutti's formula, we have for the composition of ulmic acid, 30 atoms carbon =22-5 or per cent. 57*15 15 atoms hydrogen = 1-875 — — 4-76 15 atoms oxygen = 15*0 — — 38*09 39*375 100*00 This constitution agrees exactly with the previous experiments of Boullay. M. Malagutti has found, that when the boiling of ulmic acid with an acid is continued, a black insoluble matter is depoE , jd, which he calls ulmin. In its composition it agrees exactly with ulmic acid. * Jour, de Pharm. xxi, 453. i III i in I I; ' I 120 OILY ACIDS. CHAPTER III. OF OILY ACIDS. These acids are so called, because they are formed from oils or fat, and enter into the composition of soaps ; or because they possess many of the characters of oils. They are 23 in number, and were first investigated by M. Chevreul, who devoted ten years to the assiduous study of the chemical properties of fixed oils and fats. The following table exhibits their names and constituents, or at least, their ratios : — 1 Butyric . 2 Smilacic . 3 Phocenic 4 Hydrospiroilic 5 Caproic . 6 Spiroilic 7 Chlorophenisic 8 Chlorophenesic 9 Oenanthic 10 Anchusic 11 Roccellic 12 Capric 13 Ricinic 14 Santonin . 15 Stearic 16 Oleic 17 Metoleic . 18 Hydr oleic 19 Margaric 20 Metaraargaric 21 Hydromargaric 23 EkTodic^ Not yet analyzed. Several of these acids have been described in the Chemistry of Inorganic Bodies, (vol. ii. pp. 122 to 139). I shall here give an account of the new oily acids which have been discovered since the publication of that work, and of the new views respect- ing some of the acids of Chevreul, which have resulted from later experiments. SECTION I. — OF MARGABIC ACID. When margaric acid is mixed with a fourth part of its weight of quicklime, and distilled in a retort, there comes over first a small quantity of water. Then a soft matter, which, when pressed be- tween the folds of blotting paper, gives out oil, and a white sub- stance remains, the properties of which will be immediately described. C» H« O^" C« H7» O'' C'o Wi 0» C'» H« 0* C'2 H>o 0" C'^ Hs 0» Cia H3 0» ChF C12 H3 0^ ChF C* H^' 0^ C'^ H'o 0* C'7 H'« 0* C'8 H'* 0' QH HU 0* C60 H3« 012 QU H68 0* (J70 Hoa 0^ C70 H64 0» C^" H" 010 C" H6» 0« Q10 H6' 0« C70 H70 09 MARUAUIC ACID. 121 give later Hit of small be- Isub- ibed. The last portions of the acid undergo a more complete decomposi- tion, for the matters pass over coloured and cmpyreumatic, and there remain behind, in the retort, lime, and carbonate of lime, blackened by a small quantity of charcoal. Forty parts of margaric acid, thus treated, yielded 28 parts of solid matter, of a light-yellow colour, which, when exposed to pressure, left 22 parts of a hard white solid matter, to which M. Bussy, to whom ^ are indebted for these ex- periments,* has given the name of viargarone. To obtain it pure, it ought to be repeatedly dissolved in alcohol, and allowed to sepa- rate by crystallization. Margarone thus purified is white, brilliant, and has a pearly lustre. It melts when heated to 170", and crystallizes confusedly on cooling, bearing in that state some resemblance to margaric acid or spermaceti. It is a non-conductor of electricity, and be- comes electric by fricti(m or by pressure. When heated in a retort it boils, and may be distilled over without alteration, and without leaving any residue. It burns with a bright flame, and without smoke. It dissolves in 50 times its weight of boiling alcohol of the specific gravity 0'836. But the greater part is deposited when the alcohol cools. Water also throws it down from this solution. It is more soluble in alcohol of 0*817, 3 parts dissolving in 20 of the alcohol. The solution becomes solid on cooling. Ether, at the boiling point, dis- solves about f ths of its weight of it. But the greatest part preci- pitates when the solution cools. Acetic ether, and likewise oil of turpentine, dissolve it abundantly. It combines with camphor in all proportions. When boiled with concentrated potash ley, it undergoes no altera- tion, being incapable of forming a soap. Sulphuric acid deepens its colour, and decomposes it with the disengagement of sulphur- ous acid. One part of margarone gently heated with two parts of sul- phuric acid becomes first red, then brown, then black, and is soon converted into a mass of charcoal. Nitric acid acts on it \ery feebly, even when assisted by heat. When exposed in a tube to a current of dry chlorine gas, and under the influence of a gentle heat, it is transformed completely into a colourless transparent viscid liquid. Margarone has considerable resemblance to paraffin. But paffin melts at 110°|, and 'n not altered by sulphuric acid. Margarone was an:tlyzed by M. Bussy by means of oxide of cop- per. He found it composed of Carbon .... 82-22 Hydrogen .... 13*51 Oxygen . . . . 4*27 100*00 Now, according to the analysis of M. Chevreul, margaric acid is composed of # Ann. Ue Chim. ct de Phys. liii. 398. ii;,!l 198 OILY ACIDS. i ii Carbon I lydrogen 12-()10 100-00 And he considers its constitution to be C"* W^ O^. Now, the numbers obtained by Uussy for margarone, j^ivo us for its constitu- tion C^* W* O, so that it differs from niargaric acid by wantin<^ an atom of carbonic acid. The atom of mar This le crys- Iprocess Ved on When hmonia, liquid ^aurent pult :— )2 a 2 [o SANTONIN. 133 These numbers do not correspond well with the result of his ana- lysis. But the reason of this he supposes to be, that the acid, as he examined it, containevi a mixture of chlorophenisic acid. If we admit the presence of an atom of water, as in the chloro- phenisic acid, then the true constitution of chlorophenesic acid will be 12 atoms carbon . . . =9 4 atoms hydrogen . . . = 0*5 2 atoms oxygen . . . = 2 2 atoms chlorine . . . =9 20-5 So that its atom'c weight is 20*5, and it differs from chlorophenisic acid by v^ntaining 1 atom more of hydrogen, and 1 less atom of chlorine. The excess of chlorine (more than 1 per cent.) was owing tu .he existence of chlorophenisic acid in the chlorophenesic acid analyzed ; for when kept for some weeks it had deposited a small quantity of that acid. Chlorophenesic acid will be converted into chlorophenisic acid, if we substitute an atom of chlorine for one of the atoms of hydrogen which the former acid contains. SECTION X. — OF SANTONIN. This substance, which possesses acid properties, though its affinity for bases does not seem very strong, wa'- 'iscovered about the same time by Kohler and Alms, in the seeds v.* the artemisia sontonica, or southernwood. Its properties were afterwards examined more in detail by Trommsdorf, junior.* He procured it in the following manner : — Four parts of coarsely pounded seeds of santonicum were mix^'d with 1 ,]- parts of dry quicklime, and digested three times in sucr sion with from 16 to 20 parts of spirits, of the specific gravity Q'\)t. These three solutions were mixed and distilled, till only about 14 parts remained. This last portion was allowed to cool, and then iiltered, to separate the matter which had been deposited. The filtered liquid contained a compound of lime and santonin. It was evaporated to half its original bulk, and, while still warm, mixed with acetic acid in excess, and left to cool. The santonin was gradually der tsited in feathery crystals, mixed with a brown resinous body, the combination of which, with lime, existed also in the solution. The mother ley was evaporated to the consistence of a syrup, and then diluted with cold water. A precipitate, consist- ing partly of santonin crttals, remained undissolved. These two deposits of santonin were mixed, and treated with as small a quantity of cold alcohol as was sufficient to dissolve the resin, without dis- solving more than could be avoided of the santonin. The santonin is now collected on a filter, and washed with cold alcohol, added by little and little, till it ceases to acquire colour. The remaining san tonin is dissolved in from eight to ten times its weight of boiling * Ann. (Icr Pharmacie, xi. 190. ill I ■ I- , 134 OILY ACIDS. A alcohol, of the specific gravity 0*844, mixed with a little ivory black, agitated, filtered, and left to cool. The santonin crystal- lizes in a state of purity. It must bo carefully kept from the action ©flight. The alcohol employed in washing the santonin, contains a portion of it in solution. Distil off the alcohol, dissolve the residue in warm caustic alkaline ley, and dilute the solution with 6 or 8 times its weight of cold water. Mix it with an excess of acetic acid. The renin precipitates ; and the liquid, after filtration and some evapo- ration, deposits santonin, which must be dissolved in alcohol and crystallized. Santonin, thus obtained, possesses the following properties : — It crystallizes in six-sided prisms, in long plates, or rectangular tables and feathery crystals. It is colourless, and destitute of smell and taste ; but when long chewed an impression of bitterness is per- ceived. It refracts the light strongly, and when exposed to it for a few miniites, becomes yellow. In the dark it undergoes no change. Its specific gravity is [•247 at 70°. When h.-ated to about 27fi° it melts into a colourless liquid, which crystallizes on cooling, and loses no weight. If we raise the temperature a few degrees higher than 276°, it emits a white smoke, and may, with suflUcient care, be sublimed in needles without alteration. If the temperature be raised still higher, the sublimate becomes yellow, and does not crystallize. In the open air it burns with flame, giving out smoke. It requires between 4 and 5000 times its weight of cold, and 250 times its weight of boiling water to dissolve it. It requires 43 times its weight of alcohol of 0*848 at 59° to dis- solve it ; 12 times its weight at 122°; and only 2*7 times its weight at 176°. It requires 280 times its weight of spirits of specific gravity 0*928 to dissolve it at 59", and 10 times its weight at 178°. It dissolves in 75 times its weight of cold, and 42 times its weight of boiling ether. It is soluble likewise in fixed and volatile oils. None of these solutions act upon vegetable colours ; but the alco- holic solution has a very bitter taste. When in a state of fusion, it neither unites with sulphur nor phosphorus. Chlorine and iodine have little action on it ; but it it be heated along with them it is destroyed. Sulphuric acid dissolves santonin without altering its colour, and water throws it down again unaltered. If the solution be left to itself, it gradually assumes a yellow colour, then becomes blackish- brown, and water throws down a brown substance, which contains unaltered santonin mixed with it. If we boil it with sulphuric acid, and then dilute the solution with water, the same alteration is produced. Nitric acid of 1*35 specific gravity dissolves santonin by the as- sistance of heat, and allows it to fall again in crystals when the solu- tion cools. By long boiling in this acid, decomposition is produced, oxalic acid being formed, ami a bitter tasted substance precipitable by water. Phosphoric and muriatic acids have no action while cold, c t q c tJ e o SI b t( d ir "■ i \ SANTONIN. 135 178"= IS he as- solu- duceil, litable e cold, but at a boiling heat they dissolve santonin, and change it into a brown resinous -like substance. Acetic acid dissolves santonin cold ; hot acetic acid dissolves it in greater quantity ; but the excess crystal- lizes as the solution cools. Santonin unites with the alkalies and salifiable bases, with a weak but evident affinity. Most of its compounds with the metallic oxides are, to a certain extent, soluble in water. The saturated solutions cannot be boiled ; the bases separate and precipitate when they are insoluble, and when the liquid cools the santonin crystallizes. Santonate of potash may be formed by boiling santonin in a con- centrated potash ley. When the liquid acquires a certain degree of concentration, the salt separates in yellow oily drops, which, on cooling, constitute a soft, uncrystallizable matter, which is soluble in alcohol, and may be melted by heat. This salt is best obtained when santonin is dissolved in an excess of boiling hot carbonate of potash. The solution is to be evaporated to dryness, and the santonate obtained by digesting the residue in anhydrous alcohol. When the alcohol 10 evaporated, the santonate is obtained in a white or yel- low indistinctly crystallized maiss. It melts easily, is soluble in alcohol, and tastes and reacts as an alkali. If we dissolve it in water and boil the solution for a few minutes, the salt is decomposed, and the santonin is deposited in crystals when the solution cools. If santonin be treated with potash and weak alcohol, the liquid, during the solution, becomes carmine red, but this colour disappears as soon as the salt is formed. It may be combined with the other bases, but not without the agency of alcohol. Santonate of soda may be prepared in the same way as santonate of potash. It crystallizes in small colourless prisms, grouped to- gether, and when exposed to the rays of the sun, acquires a yellow colour. Santonate of ammonia exists only in solution. When we attempt to evaporate, the ammonia flies ofl', and leaves the santonin. We obtain santonate of lime by boiling a mixture of santonin and quicklime in spirits. The solution is freed by carbonic acid of any ex- cess of lime which it may contain. When filtered and left to spon- taneous evaporation, the salt crystallizes in brilliant needles. If tha. evaporation be pushed too far, the whole mass congeals in the fofiH of needles. This salt dissolves readily in water and in spirits, but with difficulty in alcohol. Santonate ofbarytes may be prepared in the same way, and pos- sesses analogous properties. Santonate of magnesia has not yet been prepared in a pure state, but it seems to be soluble in water. Santonate of alumina is obtained in the state of a white precipi- tate by double decomposition. It is decomposed by boiling, and dissolved in an excess of the alum solution. Santonafcs cfzinc, protoxide of iron, and oxide of copper, are soluble in a certain quantity of water, but when formed by double decom- :: t1 11 iff B 136 OILY ACIDS. positions, they separate froni tlio concentrated solution. The san- ton, ite of zino is colourless, anil crystalli/os. The protosantonate of iron is white, finely divided, and sneiMlily hecomes yellow. The santonate of copper, in flocks and lijjrht-hlue. The per santonate of iron is isabella-yellow, and insoluble in water, but soluble in alcohol. Santonate of lead is insoluble in ('()ld water, but somewhat soluble in boilinof water. It crystallizes in tine silky needles. It is soluble in idcohol, and crystallizes when a .--iiturated boilinjr solution is left to cool. When boiled with an excess of ucetate of lead, it is changed into a disalt, and the santonin is left behind. Santonate of silver is a white precii)itate, soluble both in water and in alcohol. Santonate of black oxide of mercury is white, insoluble in water, but soluble in alcohol. Santonate of red oxide of mercvry U sd soluble that it does not separate, except from a very concentrated solution. It is very soluble in alcohol. A saturated boiling solution of santonin in water gives, with in- fusion of nutualls, a yellow precipitate, soluble in alcohol. The change of thy colour of santonin from white to yellow, when exposed to the sun's rays, is remarkable. This change takes place in vacuo, and under water, alc(»liol, ether, oils, &c. When fused, santonin is exposed to the light of the sun, it splits in all directions. The violet end of the sj)ectrum acts much more powerfully upon santonin than the rod end. The common light of day acts slowly. After this change has taken place, the; red colour, observable when santonin is acted on at once by potash and alcohol, does not appear. Tlic colour becomes yellow, and this colour disappears when the alkali is saturated. The yellow uncrystallized body, obtained by the sublimation of santonin, deserves attention. It is insolnble in water, but dis- solves readily in alcohol, ether, and potash. With the uncom- bined alkalies it strikes an intensely red colour, .and might be em- ployed as an excellent re-agent for detecting their presence It is the change of the santonin into this yellow substance by heat, that occasions the red colour, when heat is ap})lied to an alkali and al- cohol in contact with santonin. Liebig has given us the result of an analysis of santonin, partly by himself, and partly by Ettling and Laubenheimer : — Carbon 73*()3 or 5 atoms = 3*75 or per cent. 73' 17 Hydrogen 7*2 1 or 3 atoms = 0-375 — — 7*32 Oxygen ,19-lG or 1 atom = I'OO — — 19*51 100-00* 5-125 100-00 The atomic weight of santonin not being known, these nund)ers supi)ly us only with the ratios of the atomic constituents. It is ob- * AniuiK'ii (Icr riianiiuclo, xi. -JO". I'' SMILACIN. 137 111- when imation flit dis- mcorn- |bc cm- It it, that ind al- I partly Imbers is ob- vious, from the phonomona, tliat this atomic wciglit is much hij^her than 5' 1 25. Licbijr supposes it to bo 12 times as hi<5'h. This would make santonin a compound of CO atoms carbon . . . ■= j 30 atoms liydroffen . . = 4*5 12 atoms oxygen . . =12 61-5 This would make the atomic weight 61 "5. Liebig observed that the alcoholic solution of santonin reddens litmus. It is obvious that it possesses the characters of an oily acid. SECTION XI. — OF SMILACIN. I place this substance here, though its acid characters have not been accurately determined, on account of the great resemblance which it bears to santonin. It is obtained from the root of the smilax sarsaparilla, or the sarsaparilla of apothecaries. This root was first examined by Pal- lota,* who extracted from it a peculiar substance, to which he gave the name of parifflin. It was afterv/.ards examined by Folchi, and called by him smilacin. Thubcuf followed next, and gave it the name of sasseparin.'f Batkat published a set of experiments on the root of the sarsaparilla, and drew as a conclusion from them, that the pe- culiar substance distinguished by the above names was an acid, to which he gave the name of pnrillinic odd. Poggiale§ has examined tlie statements of his predecessors, and has come to the conclusion, that the paritjlin, smilacin, sasseparin^ and parillinic acid are all one and the same substance, under differ- ent names. To this substance, the properties of which he has eaxmined, he has given the name of sasseparin ; but the term smilacin, applied to it by Folchi, is so much more agreeable to the ear, that there can be no hesitation in adopting it. The best mode of procuring smilacin is the process of Thubeuf. It is as follows : — Digest the root in warm alcohol. Distil off ^tlis of this tinc- ture. Digesst the residue for 24 hours with ;inhnal charcoal, and filter while th'j rupiid is still hot. On cooling, the smilacin is deposited in crystals. By repeated solutions and crystallizations, it is obtained pure. If we ev;'porate the mother ley to dryness on the water-bath, and treat the dry residue with hot water, resin and fatty matter are left behind. The aqueous solution being evapo- rated to dryness, and the residue treated with alcohol, we may ob- tain more smilacin by evaporating the alcohol. Smilacin thus obtained is a white powder, which, when dissolved in alcohol, and left to spontaneous evaporation, crystallizes in fine needles. They are white and tasteless while solid, but have a bitter * .lour, tie Pliarmacir, x. .54.). f Ibid, xviii. 7.14. J Ibid. xx. 4;J. § Jour, (le Cli. Medic, x.577, or Jour, do I'liarmacic, xx. .553. It \'j i:38 OILY ACIDS. ■ I t ^1 taste when dissolved. They uro heavier thun water. They tlis- Bolve with difficulty in cohl, but more easily in boiling water. They dissolve in alcohol whether hot or eold. Hoth the a«{ueous and al- coholic solutions froth liki> soap-suds when agitated. Sinilaciu is soluble in hot ether and in volatile nils, and somewhat soluble in fixed oils. When heated it melts into a yellow licjuid, is charred and de- stroyed, leaving a very brilliant charry matter behind. It is soluble in dilute acid and alkaline solutions, and is thrown down when the acids or alkalies are saturated. In these respects it is analogous to santtdiin. Sulphuric acid gives it a dark red colour, which clianges to violet, and lastly to yellow. Hut water throws down the smilacin unaltered. Hy nitric acid it is very slowly converted into a yellow substance. When dissolved in muriatic acid, and the solution eva- porated on the water-bath, the smilacin is deposited in beautiful crystals. Smilacin was analyzed no fewer than 12 times by Poggiale,* once by Henry. The mean of these analyses gives Carbon ()2'38 or 9 atoms = 6*75 or per cent. r»3'15 Hydrogen 8-86 or 7 J atoms = 0-9375 — — 8-77 Oxygen 28-6() or 3 atoms = 3-00 — — 28-08 and 100-00 10-()875 100 According to Poggiale, the crystals contain 8-5G per cent, of water. If this be one atom, then the atomic weight of smilacin will be 12. For W'ater . . . 8-5G or 1-125 Smilacin . . . 91-44 or 12-01 It is evident from this, that the formula deduced from the analyses, is not correct. 1-3125 = 1 atom oxygen + 2^ atoms hydrogen be- ing wanting to make up the etomic weight 1 2. SECTION XII. — OF OSNANTHIC ACID. This acid was discovered by Liebig and Pelouze, constituting one of the component parts of cenanthic ether to which wines owe their peculiar smell. If the oily liquid obtained in small quantity when wine is distilled, be agitated with carbonate of soda, the alkali is gradually saturated with a'nanthic acid, provided the quantity of the oily liquid be sufficient. On adding sulphuric acid to the a-nanthate of soda thus formed, the acid separates in a buty- raceous state. It must be washed with hot water, and then dried, either by agitation with chloride of calcium, or in vacuo over sul- phuric acid.t (Enanthic acid thus obtained, at the temperature of 55°;], is snow-white, and has the consistence of butter. At a higher tem- perature it melts into a colourless oil, without taste or smell, which * He analyzed tliree times successively, sasscparin, pariylin, parilUnic acid, and smilacin, and found the coinpusitiun ufali the same. f Ann. do Chim. et de Pliys. Ixiii. 1 18. ley dis- . Thev nnd uf- iliu'in is lublu in and (le- I sulublo hen tho 3gOU8 to fliaiiiceedmgly easily decomposed, and it is difficult to obtain them in a definite state of composition. Very often they are mixtures of supertcnanthates and ocnanthates in various proportions. This makes it hardly possible to determine the atomic weight by analysis. The cenanthate of co|)per was found composed of CEnanthic acid . 74-03 or 14-25 Oxide of copper . 25-97 or 5 malyses, logon be- stituting ]h wines in small |of soda, Ided the iric acid a buty- m dried, )ver sul- i^o.|, IS lier tem- which Inic acid, ^ 100 This would make the atomic weight of the acid 14-25. CEnanthic acid, when first prej)arcd, contains an atom of water ; but when distilled it abandons its water and becomes anhydrous. In both states it was analyzed by Liebig and Pelouze. They found the hydrous acid composed of Carbon 68-39 or 14 atoms z= 10-5 or percent (58-86 Hydrogen 11-73 or 14 atoms = 1-75 — — i ' 47 Oxygen 19-88 or 3 atoms = 3 — _ l'j-67 100 15-25 100 The anhydrous acid has a higher point of boiling than the hydrous. Its point of fusion is also higher. \^ hen liquid, it does not become solid till cooled down to 88°. Its constituents were found to be Carbon 73-88 or 14 atoms carbon = 10-5 Hydrogen 12-19 or 13 atoms hydrogen = 1-625 Oxygen 13*93 or 2 atoms oxygen = 2 100-00 14-125 It is obvious to tho eye that it contains an atom of water less than the hvdrous acid. ■ . i - '; i, • i 140 ACIDS CONTAINING AZOTE. The composition of cenantluc ether, which will be given in a sub- sequent part of this work, leaves no doubt that the atomic weight of this acid is 14-125, and that its constitution is C* H'^ O^ CHAPTER IV. ACIDS CONTAINING AZOTK. m. i ll-. ! '( . : : ij J ' t ' ' i:h These acids (excluding a few belonging to the order of pound acids, and the acids from cyanogen,) are 8 in number, following table exhibits their names and composition com- The 1 Azulmic 2 Indigotic 3 Carbazotic 4 Aspartic 5 Cliolesteric 6 Ambreic 7 Nitrosaccharic 8 Nitroleucic (.8 C" CIS c» CI3 C" H* Az* O* H7iAz»*0'« Az'' 0'« H'^ Az 06 H'^Azi 0« H47Az* 0^7 Not analyzed. SECTION I. OF AZULMIC ACID. When an aqueous or alcoholic solution of cyanogen gas is left in a well stoppered phial, it undergoes spontaneous decomposition, and a dark-brown substance, almost black, precipitates. To this sub- stance M. PoUydore BouUay has given the name of azulmic acid.* It is insoluble in water whether cold or hot. It is equally insolu- ble in alcohol ; out concentrated nitric acid dissolves it without the assistance of heat, and it assumes a beautiful aurora-red colour. Water renders this solution muddy ; but the precipitate dissolves in alka- line bases and in ammonia. The solution has a very deep-brown colour, similar to that of ulmate of potash, only a good deal redder. The acids throw down from it a very light precipitate of a reddish- brown colour, which, when dry, is nearly destitute of lustre, and it has a good deal of resemblance to china ink. The metallic salts throw down a brown precipitate, and completely deprive the solution of colour. When heat is applied, azulmic acid is converted into hydrocyanatc of ammonia, which sublimes, and, if the heat be still farther raised, a gas is evolved, which burns with a blue flame, and has the odour of cyanogen : a quantity of charry matter remains in the retort. Several interesting experiments on azulmic acid have been made in the course of the winter 1837-8, by M. Pelouze and Mr Richard- son, in M. Pelouze's laboratory in Paris. They first analyzed the azulmate of silver and found it composed of i,,f ♦ Ann. de Cliim. ct de Plivs. xlii. "JSl. 'I in a sub- veight of of com- !r. The is left in tion, and this sub- ic acid.* y insolu- hoiit the . Water in alka- ip-brown redder, reddish- , and it Inpletely nic acid and, if with a charry bi made Lichard- fzed the INDIGOTIC ACID. 141 Azuhnic acid Oxide of silver 17-57 14-5 32-07 Indicating 17*57 for the atomic weight of that acid. This salt being analyzed by means of oxide of copper, gave Carbon 18-884 or 8 atoms = 6 or per cent. 18-75 Hydrogen 1-833 or 4 atoms = 0-5 — — 1-56* Azote 21-868 or 4 atoms = 7 — — 21-87 Oxygen 12-149 or 4 atoms = 4 — — 12-50 Oxide of silver 45-2G6 or 1 atom :^ 14-5 — — 45-32 100-000 32 100 Hence the formula for azulmic acid is C* H'' Az* O*, and its atomic weight 17-^. When cyanogen undergoes spontaneous decomposition in water, it has been inferred by Pelouze and Richardson, from their experi- ments, that for every 1 1 atoms of it which undergo decomposition, 17 atoms of water are decomposed at the same time. 11 atoms of cvanogen are C^'^ Az" 1 7 atoms water are Making together They are converted into 1 atom urea . 3 atoms hydrocyanic acid 4 atoms carbonic acid 1 atom ammonia HIT QU C22 Az'i W^ O'^ C^ Az2 H* O^ C Az3 W C* 08 Az IP 1 atom oxalate of ammonia C Az H' O' 1 atom azulmic acid C» Az' H* O* C22 Az" H'7 O'^ These atomic numbers agree with the atomic weight of 1 1 atoms of cyanogen; but the supposition that 11 atoms cyanogen and 17 atoms water undergo mutual decomposition seems rather strained. SECTION II. OF INDIGOTIC ACID. To the account of indigotic acid given in the Chemistry of Inor- ganic Bodies (\o\. ii. p. 153), I have the following addition to make: This acid has been called nitranilicf by Berzelius. Besides the analysis of Buff, given in the Chemistry of Inorganic Bodies, there is another which he made at a later period, and which he considered as more exact. It is as follows . — Carbon 49-575 or 15 atoms = 11-25 Azote 7*588 or 1 atom = 1-75 Oxygen 42-837 or 10 atoms = 10 100-0001 23-00 * Reckoning the hydrogen 1 atom less than given by the analysis, f From anil, a species of the Indujopera. % Ann. de Chim. et de Phys. xli. 176. ii L 142 ACIDS CONTAINING AZOTE. ii \i fi t !' ■n\ ill' i f r I i Buff found indigotate of barytes composed of Indigotic acid . . 10 or 13"57 Barytes . . . 7 or 9*5 17 This would make the atomic weight of the acid only 13'5, while the weight derived from indigotate of lead is 27*08, or just double. But Dumas, who has analyzed this acid with great care, and in a state of great purity, has found hydrogen one of its constituents. According to him it is composed of Carbon .... 48*09 Hydrogen .... 2*61 Azote ..... 7*40 Oxygen . . . . 41 "90 100-00* From this analysis the following formula may be deduced : 23 atoms carbon = 17*25 or per cent. 48*17 7 J atoms hydrogen = 0*9375 — — 2*61 U atom azote = 2*625 — — 7*33 15 atoms oxygen =15 — — 41*89 35-8125 100*00 So that it is merely indigo, containing five times as much oxygen as that pigment does. SECTION UI. OF CARBAZOTIC ACID. This acid has been described in the Chemistry of Inorganic Bodies, (vol. ii. p. 151). It has been called nitropicric\ by Berzelius. Its composition, as determined by Liebig's analysis, is Carbon 36*081 or 5 atoms = 3*75 Azote 16*714 or 1 atom = 1-75 Oxygen 47*205 or 5 atoms = 5 100*000 10-5 But as the atomic weight is above 30, we must multiply these numbers by 3. This gives us 15 atoms carbon . . . =11-25 3 atoms azote . . . =5-25 15 atoms oxygen . . . =15 31-5 This gives us 31-5 for the atomic weight of carbazotic acid, which is very nearly the mean of the numbers derived from Liebig's analysis of the carbazotates of potash and barytes, as given in the Chemistry of Inorganic Bodies (vol. ii. p. 152), that mean being 30*7. Om * Jour, de Pharmacie, xx. 32. f From nitro, and «-<*j»», hitter. ASPARTIC ACID. 143 /hile the ible. !, and in tituents. xygen as Bodies, fy these which ^iebig's in the being Dumas has subjected this acid to a careful analysis, and considers its constituents to be atoms = 9'375 or per cent. 31*25 atoms = 0-375 — — 1-25 atoms = f)'2b — — 17*5 atoms =15 — — 50 31*3 or 121 Carbon Hydrogen 1*3 or 3 Azote 17*7 or 3 Oxygen 49*7 or 15 100-0* 30 100-0 SECTION IV. — OF ASPARTIC ACID. In the Chemistry of Inorganic Bodies (vol. ii. p. 160), the dis- covery and character of this acid have been given. Since that time it has been shown that asparagin, a crystallized substance discovered in 1805, in the juice of asparagus, by Robiquet, and still more abundant in the althcea officinalis, is nothing else than aspartate of ammonia,\ or rather asparamide. This curious discovery was made by MM. Boutron-Charlard and Pelouze.if These chemists obtained asparagin from the roots of the althoea by cutting them into small pieces, and macerating them twice successively in four times their weight of cold water, filtering the liquor through cloth, concentrat- ing it sufficiently over the water-bath, and setting it aside for four or five days in a cold place. The asparagin was deposited in crystals. They procured aspartic acid by boiling an excess of barytes water with asparagin till all the ammonia was disengaged. The liquid was then filtered, and the barytes exactly saturated with sulphuric acid while the liquid was hot. On cooling, the aspartic acid almost wholly precipitates in small silky crystals. Aspartic acid, when exposed to a heat of 248°, loses no weight. But Liebig has shown that it contains 2 atoms of water.§ Its atomic weight was determined by analyzing the aspartates of lead and silver. Aspartate of lead, dried at 248°, was composed of Aspartic acid . . 669 or 14-68 Oxide of lead . . 638 or 14 Aspartate of silver was composed of Aspartic acid . . 430 or 14-5 Oxide of silver . . 430 or 14-5 According to these analyses , the atomic weight of aspartic acid ap- pears to be 14*5. Aspartic acid, in the state of crystals, was analyzed both by MM. Boutron-Charlard and Pelouze, and by M. Liebig. They obtained the following results : — * Jour, (le Pharmacie, xx. 32. •f- Agedoxte of liquorice root is the same as asparagin. See Jour, de Pliarm. xiv. 177. The althein discovered by Bacon in the root of the althea officinalis (Ibid. xiii. 24) has been shown by M. Plisson to be the same as asparagin. (Ibid. p. 477.) \ Ann. de Chim. et de Fhys. lii. 90. § Ibid. liii. 419. m 144 ACIDS CONTAINING AZOTE. ' (. «: I 1\U 'h, P ' i'i'll Boutron and Pclouze. Liebig.* 38-771 36-041 5-500 5-355 11-266 10-386 44-463 48-021 100-000 99-803 Carbon Hydrogen Azote Oxygen These numbers do not differ much from each other, except in the oxygen and carbon. Liebig's numbers gave an atom of oxygen more than the others. If we adopt his analysis as most exact, we obtain the composition of crystallii^ed aspartic acid as follows : — 8 atoms carbon — 6 or per cent. 36-10 7 atoms hydrogen ^ 0-875 — — 5-27 1 atom azote =: 1-75 — — 10-51 8 atoms oxygen =: j-00 — — 48-12 16-625 100 But the atomic weight of the acid, instead of 16-625, was found only 14-5. This shows us that the crystals contain two atoms water, and that anhydrous aspartic acid is composed of 8 atoms carbon =6 or per cent. 41-74 5 atoms hydrogen = 0-625 — — 4-34 1 atom azote =1-75 — — 12-18 6 atoms oxygen = 6-00 — — 41*74 14-375 100-00 ' SECTION V. — OF CHOLESTEniC ACID. In the Chemistry of Inorganic Bodies (vol. ii. p. 143), an analysis of cholesterin by Chevreul has been given. It has been since sub- jected to a new analysis by M. Pelletier,t who found it composed of Carbon 83-37 or 33,^ atoms = 25-125 or per cent. 83-40 Hydrogen 13-32 or 32 atoms =4 _ _ 13-28 Oxygen 3-31 or 1 atom =1 — — 3-32 100-00 30-125 100 This is the very constitution of ambrein, so that, according to these analyses, ambrein and cholesterin are isomeric bodies. Pelletier likewise subjected cholesteric acid to analysis, and obtained Carbon .... 54-93 Hydrogen .... 7*01 Azote . . . . 4-71 Oxygen .... 33-35 100-00 In the Chemistry of Inorganic Bodies (vol. ii. p. 144), it is shown that the atomic weight of this acid, deduced from the best analyses * Ann. de Chiin et de Pliys. liii. 419. f Ibid. Ii. 188. AMUUEIC ACID. 145 )t in the oxvffen tact, we as found atoms 1 analysis ince sub- nposed of 13-40 3-28 3-32 to these 513, and is shown analyses at that time made, is 18. Pelleticr considers his analysis of choles- terate of strontian as the most exact. He found ii compose^ of Cholesteric acid . . 100 or 17'57 Strontian . . . 36*98 or 6'5 130-98 According- to this estimate, the atomic weight of cholesteric acid is 17-57. Now if it he composed of 13 atoms carbon = 9*75 or per cent. 54-5 10 atoms hydrogen - 1-25 7-0 1 atom azote -0-875 4-9 6 atoms oxygen = G-00 33-6 17-875 100-0 we obtain 17*875 for the atomic weight, and the resulting numbers agree very well with the analysis. SECTION VI OF AMBREIC ACID. In the Chemistry of Inorganic Bodies (vol. ii. p. 141), the history and characters of this acid have been given, together with the pro- perties of ambrein, from which it was obtained by the action of nitric acid. M. Pelletier has since subjected both ambrein and ambreic acid to an ultimate analysis, by means of oxide of copper.* Ambrein is composed of Carbon 83-37 or 33| atoms = 25-12.5 or per cent. 83-40 Hydrogen 13-32 or 32 atoms =4 — — 13-28 Oxygen 3-31 or 1 atom = 1 — — 3-32 M. 100-00 30-125 100-00 Pelletier found the constituents of ambreic acid as follows : — Carbon 51*942 or 57 atoms = 42*75 or per cent. 51*74 Hydrogen 7*137 or 47 atoms = 5-875 — — 7*11 Azote 8-505 or 4 atoms = 7-00 — — 8-47 Oxygen 32-416 or 27 atoms = 27-00 — _ 32*68 100-000 82-625 100-00 It is needless to speculate upon the composition of ambreic acid till its atomic weight be determined. But it would not be surprising if it were nothing else than a combination of an integrant particle of ambrein, deprived of a certain quantity of carbon and hydrogen, with two atoms of nitric acid. 2 atoms ambrein are C" H*'* O^ 1 atom ambreic acid C/^ H*^ O" Az* Abstracted . . . C'° H^ Added .... 02« Az* The oxygen in this quantity exceeds that in nitric acid by about ]th part. But the real quantity of oxygon in ambreic acid is less * Ann. de Chim. et de Phys. li. 188. i ' I 1 1 !l, i 1^ 1 i A i Nl H ■^M 14f) ACIDS IMPERFECTLY EXAMINED. tlian 27 atoms : find if ambrein contain no oxygen, the discrepancy would be dimi:. sled somewhat. I have no addition to make to the account of the nitrosaccharic and nitrokneii' aci la, given in the Chemistry of Inorganic Bodies (vol. ii. pp. 162 and 164). CHAPTER V. ACir.S IMPERIFCTLY EXAMINED. These acids, 23 in number, lave not yet been subjected to a chemical examination. This puts it out of our pov.er to !!ran<:'c. them, and makes it necessary to jnit them ir\ an order ))y theiuholvcs. This order will, of course, disappear when liie necess'ry chtdtical examination of the acids arranged under it bn;-; taken placn. section I. OF 1 f,CTIC ACID. I l;ave nothing to add to the account of this acid, given in the Cht7nisfry of Inorganic Bovhichgt'!atiuiz(vi, and which, on that account, has been long fairjiliiir to most persons This substanf e has a very intimate connection with pectic acid, beini; iiiBtantly converted into that acid by the smalle^st quantity of ;» ^.%• fainilia/ mnection d by the leen dis- *;amining i>rtant of it as the aid Gui- ld! (ation If we louple of Ited in a lal pres- state of Isinglass. Ibtaining ?ith the Decant le liquid l^eight of rming a \ Boiling water has less action than cold water upon dry pectin. It dissolves also to a certain extent in dilute and boiling-hot alcohol. But the solution cannot be used as a paste, like a solution of gum or starch ; nor has it the property of reddening litmus paper. The least trace of a fixed alkali instantly converts it into pectic acid. The carbonate of potash has the property also of converting it into pectic acid. But neither carbonate of soda, nor concentrated ammonia possesses that property. If we add an excess of potash or soda to the solution of pectin, the whole of it precipitates in the state of subpectate of the alkali. Lime water converts pectin, at least parti£^lly, into pectic acid. It is precipitated in gelatinous masses, soluble in dilute nitric acid oy the soluble salts of barytes and strontian, the acetate of lead, the nitrate of copper, the nitrates of mercury, the sulphate of nickel, and the chloride of cobalt. It is not altered by the infusion of nutgalls. When distilled it does not melt, but gives off an empyreumatic oi! and an acid product, in which M. Braconnot could not detect the presence of ammonia. There remains in the retort a very bulky charcoal, which, after incineration, leaves a yellow ash, con- sisting of carbonate of lime, sulphate of lime, phosphate of lime, and peroxide of iron. When pectin is treated with nitric acid, it furnishes mucic and oxalic acids, and a slight trace of a bitter yellow matter. Muriatic acid, heated with pectin, assumes a fine red colour, and red flocks are separated, which are insoluble in ammonia. Such are the properties of pectin, as they have been determined by Braconnot. He found pectin also in the bark of all the trees which he examined. As neither pectic acid nor pectin have been subjected to analysis, we do not know the relation in which they stand to each other. One of the most striking differences between them is the action of cold water. Dry pectin, when put into cold water, swells up very much, and gradually dissolves, while pectic acid, under the same circumstances, is scarcely altered. We still want a more minute examination of pectic acid and pectin ; and, above all, a chemical analysis of each, to enable us to understand the relation in which they stand to each other. SECTION 11. OF CRENIC ACID. This acid was discovered by Berzelius, in the year 1832, in the water of Porla well, near Orebro, in Sweden. He had examined this water in 1807, and published the results of his analysis in the first volume of the Afhandlingar (p. 145). The crenic acid in that analysis was distinguished by the n?me of extractive matter. He recommenced his examination of this water again, and published the result in the Memoirs of the Stockholm Academy for 1833.* * Kong. Vet. Acad. Handl. and 238. 1833, p. 18; and Poggendorf's Annalen, xxiz. 1, M i W ii^ll ' :i '.!' I ,:, :i i ■, 1 ij. 1 1 t . (\ii li 148 ACIDS IMPERFECTLY EXAMINED. Porla water, though it proceeds from a stroDg spring, yet is so much charged with crcnic acid,* that it has a yellow colour and a disagreeable taste. When left exposed to the air, the water lets fall an ochrey sediment, consisting chiefly of crenated peroxide of iron. Ber/elius found the constituents in 100,000 parts of this water to be, Water . . . . . . 99970-5942 Chloride of potassium . . 0"3398 Chloride of sodium . . . 0'7937 Crenate of soda . . . 0*6413 Crenate and carbonate of ammonia 0'8()08 Bicarbonate of lime . . . 9*0578 Bicarbonate of magnesia . . 1*9103 Bicarbonate of manganese . 0*0307 Bicarbonate of iron . . . ()*(il09 Phosphate of alumina . . 0*0110 Silica 3*89(>0 Crenic acid .... 5*2535 29*4058 It was from the ochrey deposits that Berzelius obtained the new acid, in (juantity sufficient for examination. It was composed of Crenated peroxide of iron . 90*54 Carbonate of lime . . . 3*54 Phosphate of alumina . . 0*38 Silica ..... 5*54 100*00 This ochre was boiled in caustic potash, which produced a brown solution, from which an ochrey matter fell when it was allowed to stand for some time. The ochre must be boiled with the caustic potash till the oxide of iron, instead of forming a fine powdoi , which passes through the filter, assumes the flocky appearance of the hydrated peroxide. The liquid, which has now a deep brown colour, is to be filtered, and acetic acid added in slight excess. Acetate of copper is now dropt into the liquid, as long as a brown-colour od precipitate falls. Should the precipitate be white, some more acetic acid must be added. This brown precipitate is the apocrenate of copper. The liquid thus freed from apocrenic acid is to be filtered, and saturated with carbonate of ammonia in slight excess. Add now acetate of copper, as long as a greenish-white precipitate con- tinues to fall. The quantity of this precipitate, which is crenate of copper, is materially augmented by keeping the hquid for some time between the temperatures of 140<^ and 176°. Collect this crenate on a filter, and wash it. Mix it with water (taking care not to employ too much), and pass through it a current of sulphuretted hydrogen. Filter and evaporate the liquid to dryness in vacuo, over sulphuric acid. * Named from x^ntn, a fountain. CHENIC ACIl). 149 yet is so lur and a nter lets roxido of ts of this 942 I the new osed of a brown lowed to [e caustic ji, which le of the n colour, Icetate of [colon rod •e acetic snate of filtered, Add late con- lenate of >r some lect this Ing care liuretted vacuo, (', Crenic ac id thus ohtained is yellowish-brown. If we dissolve it in absolute alcohol, a little crenate of lime usually remains undissolved. If the alcoholic solution be now evaporated to dryness in vacuo, the crenic acid remains still mixed with a little apocrenato of lime. To separate this salt, dissolve the acid in water, and add, drop by drop, to the liquid acetate of load, as long as a brownish j)recipitate falls ; filter, add diacetate of lead, and decompose the precipitate by sulphuretted hydrogen. The filtered liquid has now a yellow colour, and when evaporated in vacuo, leaves crenic acid in a state of purity. Crenic acid thus obtained has a yellow colour, and is quite transparent. It seems to have no tendency whatever to crystalli/e. It has no smell. Its taste is sharp ; at first acid, and afterwards astringent. When in solution, the astringent taste only can be ob- served. When the solution of this acid is exposed to the air, it assumes a brown colour, and apocrcnic acid is formed. In water and alcohol it is excessively soluble. Its salts resemble extracts, and are insoluble in absolute alcohol, but become more and more sohible the more water we add. When these salts are exposed to the air they become rapidly brown, and apocrenates are formed, which are easily separated by means of gelatinous ■ilumina. Crenic acid dissolves in cold nitric acid without any alteration. When heat is applied nitrous gas is disengaged, and nitric acid may be distilled over. By evaporation a yellow mass is obtained, having an intensely bitter taste. When an alkali is added, a combination takes place, and a crenate is formed. When silica is sopai'ated from a solution of crenic acid, it con- tains a quantity of crenic acid, which may be separated by an alkali, but not completely ; for, when the silica is heated, it gives out an animal smell, and becomes black. When crenic acid is distilled, it aff'ords an acid liquor, and a brownish-yellow oil. When jjotash is added, ammonia is disengaged ; showing that crenic acid contains azote as a constituent. To determine the atomic weiglit of this acid, Berzclius precipi- tated a solution of acetate of lead by pure crenic acid. The preci- pitate was white by reflected, and yellow by transmitted light. It was washed, and dried in vacuo, at a temperature of 212°. It weighed 0*59 gramme. Being decomposed l)y sulphuric acid 0*4165 gramme of sulphate of lead was obtained. Being ignited in a platinum crucible, it gave out smoke, and the weight was reduced to 0*41 gramme. It was now no longer altered by nitric acid. The matter thus driven oft' by heat, arose from a little apocrenate of lead, which had been mixed with the sulphate of lead. Now, it will be shown in the next section, that the atomic weight of apocrenic acid is I()-75. Hence the oxide of lead which was com- bined with it in the sulphate, must have been 0-0054. And this quantity must have been united with 0-0064 of apocrenic acid, making together 0-0118. This quantity must be subtracted from I i ^■■m 150 ACIDS IMPERFECTLY EXAMINED. W I I, I ! I i!' ! m ID iV the 0*59 gramme of crenate of lead analyzed, because it was foreign matter, leaving 0'5782 gramme for the crenate of lead actually ana- lyzed. Now, this gave 0*4046 sulphate of lead — •0054 oxide of lead with which it waa mixed. This amounts to 0'3i)i)2 gramme, equivalent to 0*2980 oxide of lead.* So that the crenate of lead la a compound of Crenicacid . . 28-02 or 13-498 Oxide of lead . 29-80 or 14 57-82 We see, from this analysis, that the atomic weight of crenic acid is 13-5. To verity this analysis, Berzelius saturated, as completely as pos- sible, hydrate of lime with crenic acid, filtered the solution, and evaporated in vacuo The salt constituted a dark yellow, hard translucent mass. To free it from any excess of crenic acid or acetate that might be present, it was digested two several times with alcohol, and then dried //* vacuo, at the temperature of 212°. 0*261 parts of this salt gave 0-1305 anhydrous sulphate of lime = 0-0537 lime. Hence the crenate of lime is composed of Crenic acid . . 20*73 or 13*51 Lime . . . 5*37 or 3*5 26*10 These two analyses do gi >at credit to the accuracy of Berzelius, and leave no doubt whatever that the atomic weight of crenicacid is 13*5. The salts formed by combininnr!this acid with the bases, are called crenates. They all resemble extracts in appearance, and are in- capable of crystallizing. The followinu;^ are those which have been examined by Berzelius : — 1 . Crenates of potash and soda. These salts form yellow extractive- looking substances, which are hard and crack, and are easily detached from the glass. They are neutral, have hardly any taste, but when kept in the mouth an alkaline flavour is at last perceptible. They are insoluble in absolute alcohol ; but are pretty soluble in alcohol of the specific gravity 0*86, and they are the more soluble the weaker the alcohol is. When heated, they swell up, give out a smoke having the smell of tobacco, and leave a porous coal, mixed with an alkaUne carbonate. 2. Crenate of ammonia. This salt becomes acid when we attempt to concentrate it, and leaves a brown extractive-looking matter, which reddens litmus paper. In this state it still contains much ammonia, which n?ay be separated by potash or lime. 3. Crenate of barj/tes. This salt is of such difficult solubility, that it may be obtained by double dccompo.«ition in the state of yellow flocks. But it may be dissolved in a - .fficient quantity of water, leaving a resinous-looking varnish on the vessel. * Berzelius, by not attciuiing to these correctiona, has not done justice to his own analysis, which almost coincides with that of crenate of lime. 1 19 foreign ally ana- oxide of gramme, of lead [» ic acid is ly as pos- tion, and low, hard c acid or ral times ! of 212°. oi lime = lius, and disi:3-/>. ire called d are in- ave been itvactive- letached iste, but !eptible. )luble in soluble |ve out a mixed [attempt 1 matter, [s much [ty, that yellow water, ice to his CllENlC ACID. 151 4. Crenate of lime. This salt is moro soluble than the preced- ing, but may be obtained also by do ' Ic decomposition. When crenate of jiotash is added to chloridi; of calcium, crenate of lime precipitates in pale yellow flocks ; but when we add chloride of calcium to crenate of potash, the liipiid remains clear. When dis- solved, it leaves a yellow translucent varnish, which is often mixed with a white earthy matter. Crenate of lime is completely soluble in water. When the neutral salt is mixed with an excess of acid, evaporated, and then the excess of acid removed by alcohol, there remains a light yi'llow extractive-looking and easily soluble salt. We obtain a Suosalt when the neutral salt is procii»itated by lime water. It falls in light yellow flocks. We obtain the same salt when crenate of ])otasl» is mixed with hydrate of lime- Caustic potash in that case remains in solution in the li(iuid. 6. Crenate of magnesia. It is easily soluble in water, and re- sembles the alkaline crenates. It forms also a supersalt, which is slightly soluble in absolute alcohol. 0. Crenate of alumina. When a solution of crenic acid is mixed with moist hydrate of alumina, a neutral crenate of alumina is formed, which is yellow, and insoluble in water : but it dissolves in that liquid if we add an t^xcess of acid. When the supersalt is evaporated by a gentle he^at, there remains a yellowish translucent varnish, agam soluble in water. When a solution of this salt is mixed with caustic ammonia, no precipitate falls, and when we evaporate to dryness we obtain a double salt, which is completely soluble in water. When this salt is burnt, snow-white alumina remains. Neutral crenate of alumina, when treated with ammonia, is partially decomposed. The double salt is formed, and subcre- nate of alumina remains undissolved. 7. Crenate of iron. It is soluble in water. It may be obtained directly from the ochrey deposit from the water, by mixing it with Avater, and passing a current of sulphuretted hydi'ogen through the mixture. The iron is brought into the state of protoxide, which, united to the crenic acid, remains in solution. When evaporated in vacuo, it leaves a residue similar to that from the preceding salts. But a portion of the iron is apt to be peroxydized during the evaporation. Crenic acid dissolves metallic iron with g'.i'at difficulty, and so as only to form with it a supersalt. The action wa j carried on in a cylindrical vessel, covered with a layer of olive oil, and continued for 24 hours. The olive oil became reddish-yeliow, probably from having dissolved a portion of the iron salt, which would be peroxydized by exposure to the air. The colour of the liquid was not altered. It reddened litmus paper, and tasted as a salt of protoxide of iron. When exposed to the air, brown streaks appeared in it, but vanished on agitating the liquid; but by degrees it became all brown and muddy, and when evaporated to dryness, left a crenated peroxide of iron, no longer soluble in water, mixed with crenic acid. 4i^ ^1. m I 11 ku\ .; i '■ '. ill -J! 152 ACinS IMPRRFRCTI.Y RXAMINKI). 8. Cretifitfd peroxiffc of iron, Ohtaiiicil wlu«ii cronii- acid i' iiil'^.i-d with a luuitral siilpliatcd peroxide or rldoridc of iron. A '''..'lit roddisli-j^rey priMMjiitato falls. When wa.ilicd and driod it is our;i v, and of dirty-white colour; hut when nioisttetied, heconu'sreddi.Hli-^jrey. It dissolves couipletely in unnuonia. When the solution is ev.ipo- rated, it leaves a reddish-yellow nnitter, from which water dissolves a (h)uhle salt, leavin;x hehind a sidxrenated peroxide of iron, reseni- l)lin;X in appearance liydrated peroxide of iron. The percrenate of iron is precipitated hy the fixed alkii'i(>s, hoth caustic aii. Vrenntc of mmnjaiusc. It forms a soft pale-yellow insohihlo powder. With an excess of acid, a salt is formed, which is soluhle in water. 10. Crennfc of had. This salt is hc-t ohtained hy adding crenic acid in small (puintities at a time, to a weak solution of ui . rate of lead, as long as the precipitate continuer^ to have a hrown or yellow colour. The precipitate is to he well v.ashed with cold water, andhetter still with alcohol, and dried in vacuo, over sulphuric acid. The salt is a light-grey powder, passing into yi How. It is .very slightly soluhle in water. It is also soluhle in acetic acid, and some- what in crenic acid. Hence acetate of lead is dropt into crenic acid, and the precii)itate is again redissolved. When the solution is evaporated, a granular grey j)owder is de|iosited, which does not crystallize, and when stirred, is converted into tlocks. This con- stitutes the neutral salt. The supersalt dries into a gummy mass. Suhcrenate of lead is ohtained hy mixing suhacetato of lead with crenic acid. It falls ([uite white. VVhen dried in vacuo it acquires a slight shade of yellow. A solution of chloride of lead is not pre- cipitated hy crenic acid ; hut it is hy crenatc of jjotash. 1 1. Crenatc of copper. This salt is precipitated from the acetate, hut not from the sulphate of copper, hy crenic acid. Hut crenate of potash occasions a precipitate in suljjhate of copper. The pre- cipitate appears at first to he dirty-white, hut after it has heen col- lected in the hottom of the vessel, it is light-grey, witli a strong tint of green, or yellowish-green. It retains this colour when dry ; hut it is somewhat lighter in the shade. It is very slightly soluhle in ■water, hut dissolves readily in acetic acid, or an excess of crenic acid. It cannot he completely precii)ltated, unless the solution he heated to 122". When its sohition in acetic acid is evaporated, we ohtahi much of the red compoiuid which appears when sugar is employed to produce acetate of copper. A supercrenate is formed hy adding crenic acid to the neutral solution. It dries into a gummy mass, insoluble in alcohol, soluhle in water, and having a very disagreeable metallic taste. When saturated with an alkali, it irives a double salt, to which formation the crenate of copper has as much inclination as other copper salts. It dries into an extractive-like mas?', having a metallic taste. It AI'OCnENIC ACID. \r,:\ mass. (I with acctiite, ronate le \nv- vn col- n\iy tint 7 ; I'lit iihle in cronic ion be eMs no precipitate in crenic acid, or a solubK; crenate. lIen(;o it wouhl appear that the eremite of mercury is a soluble salt. I. "J. Crenate (tf silver. Crenic acid, when dropt into a solution of nitrate of silver, jjives at Mrst no, or only a tritlin;,' precipitate, liut by degrees a greyish-white deposit takes j)lace, which after some hours assumes a tme but dark purple colour. It does not blacken. When treated with nitric acid it becomes colourless. It is soluble in ammonia withoJit residue, and the solution has a yellowish tint. If we mix a solution of crenate of potash with nitrate of silver, in such ])roportion that only a portion of the salt is decomposed, it renuiins clear, owhig to ilio lurmation of a soluble diuible salt. The solution after some days becouuvs purple red. When the solution in which crenate of silver, has jjrecipitatod is heated to 170°, the precipitate bcH'omes brownish-yoHow ; not from the formation of apocrenate of silver, but from the appearance of a .silver salt of quite another nature, which has not yet been sufficiently examined. SECTION III. — OF AI'OCUENIC ACID. This acid was obtained by digesting- the ochre from Porla well with potash, to extract the crenic acid, and then precipitating the acid by means of acetate of copi)er. The apocremite of copper falls.* It is to be washed in cold water, which assumes a yellowish colour, while the precipitate, which is a supersalt, is to be dissolved hi pure water, as it is insoluble in the saline solution. This precii)itatc while still moist is agitated in a little water, and decomposed by sulphuretted hydrogen. It is very difficult to separate the sulpliuret of copper from the solution. The best way is to eva])orate and wash the residue with absolute alcohol, which dissolves the apo- crenic acid, mixed with a small quantity of saline matter. Another portion of the apocrenic acid remains on the filter, being little soluble in water. A solution of acetate of potash removes it, and })asses with it in sMutioii through the filter. After evaporating the solution, wc separate the acetate of potash by alcohol of 0*80, in which apocrenic acid is not soluble. The apocrenate of potash may now be decomposed by muriatic acid. Apocrenic acid thus obtained is brown, and resembles a vegetable extract. Its taste is purely astringent. It is only slightly soluble I m * I'l.'ggcinlorl".. Arinalcn, xxix. '2o2. Lt'!l ■i IWm \ 154 ACIDS IMPEHFECTLY EXAMINED. ( gfp i[]!. in water, but dissolves readily in a solution of crenic acid. It is more soluble in absolute alcohol than in water, though alcohol does not act upon it immediately. It is almost entirely precipitated from its solution in water by sal ammoniac, which throws it down in dark brown flocks, soluble anew in a large quantity of water. Its com- binations with the alkalies are perfectly neutral. They hav e a blackish- brown colour, resemble an extract, and are insoluble in alcohol. It disengages acetic acid from its combinations. It is soluble in a solution of acetate of potash, which acquires the property of redden- ing litmus paper. To determine the atomic weight of apocrenic acid, Berzelius decomposed apocrenate of lead, dried in vacuo, at the temperature of 212''. 0'43(i5 gramme gave 0*268 gramme of sulphate of lead. Now 268 : 436'5 : : 19 (an atom of sulphate of lead) : 30'57 (an atom of apocrenate of lead). Each of these containing 14 of oxide of lead, it is obvious that the atom of apocrenic acid must be 16*57. Berzelius also analyzed apocrenate of barytes. He does not give us the numbers, but merely states that the result gave the atomic weight of apocrenic acid, 16*422. Now the mean of these two numbers giving almost exactly 16*5, we can have no hef.itation in adopting that number as the true atomic weight of this acid. The apocrenates have been but imperfectly examined ; owing, doubtless, to the small quantity of this acid which Berzelius had at his disposal. 1 . /Apocrenates of potash and soda. These salts are best obtained by dissolving apocrenic acid in acetate of potash or soda, evaporat- ing the solution to dryness, ar removing the alkaline acetate by alcohol. These salts dry into a black friable mass, full of cracks, which dissolves in water, giving the liquid a dark brown colour. The concentrated solution is somewhat mucilaginous. These salts are precipitated from their aqueous solution by alcohol. 2. Apocrenate of ammonia. The solution of this salt becomes acid when evaporated. 100 parts of apocrenic acid, dried in vacuo, at 212", when saturated with ammonia and dried on the water-bath, gave 113*22 parts. It would follow from this (if no water be present) that the salt is composed of Apocrenic acid . . 100 or 16*5 Ammonia . . . 13*22 or 0*82 Now 0*82 approaches 0*708, which is the third part of an atom of ammonia. It would appear from this that the salt formed was a tersalt, composed of 3 atoms apocrenic acid . . 49*5 1 atom ammonia . . . 2*125 51*625 3. Apocrenates of the alkaline earths. These salts are dark brown precipitates, which, when washed, dissolve with a yellow colour. When the solution is evaporated, a brown matter full of cracks remains, which is again soluble in water. When there is an APOCRENIC ACID. 155 ; dark yoUow full of •c is an excess of base, these salts are quite insoluble. An alkaline apocre- nate can be rendered caustic by the addition of hydrate of lime. 4. Apocrenate of alumina. Apocrenic acid has a strong affinity for alumina. When it is digested with an excess of hydrate of alumina, the apocrenic acid is precipitated in combination with the alumina. When the alumina is not in excess, apocrenate of alumina is found in the solutions. When apocrenate of potash is digested with hydrate of alumina, the liquid becomes colourless, and a mere trace of apocrenic acid remains in the solution. The precipitate is dark brown, and contains both potash and alumina. When digested in ammonia, nothing is dissolved, or only a little crenate of alumina. After evaporating the ammoniacal liquid, a brown mass remains, from which water dissolves a supersalt, com- posed of crenic acid, alumina, and ammonia, and apocrenate of alumina remains undissolved. Superapocrenate of ammonia dissolves a portion of hydrated alumina. But when the acid becomes saturated, the whole apo- crenate of alumina falls down. 5. Apocrenate of iron. This salt is soluble in water, but when exposed to the air, it passes to the state of a subapocrenated per- oxide. We obtain the subapocrenate of iron when apocrenate of potash, mixed with a little caustic ammonia, is mixed with a salt of protoxide of iron. It falls in black flocks, which become brown in the air, quite similar in colour to the ochre from the Porla well. 6. Apocrenated peroxide of iron. It is a black flocky precipitate, obtained by dropping apocrenic acid, or an apocreniite, into a neutral solution of sulphated peroxide of iron. It dissolves with a black colour in caustic ammonia. After evaporating the solution to dryness, there remains a black matter like an extract, from which water dissolves a neutral double salt, and leaves behind a subsalt of peroxide of iron. Caustic potash, dissolves apocrenated peroxide of iron, but a precipitate almost immediately falls. It consists of subapocrenated peroxide of iron, while apocrenate of potash remains in solution. Yet the solution still contains iron. 7. Apocrenate of copper. When obtained by precipitating acetate of copp.r, it is a supersalt, having a brown colour, and a mucilaginous consistence. Water dissolves a small quantity of it, and assumes a dark yellow colour. The solution has a metallic taste, and when evaporated, leaves a blackish-brown residue, again soluble in water. When the yellow solution is mixed with a small quantity of alkail, we obtain a precipitate similar in appearance, which is a neutral apocrenate of copper. With ammonia and soda it forms double salts. Such are the characters of the crenic and apocrenic acids, so far as they have been ascertained. Berzelius is of opinion that they occur frequently in waters, and that the substances so often described by chemists, as existing in mineral waters, and which they have distinguished by the name of extractive, in reality consists of these acids. He thinks too that they exist abundantly 'n bog iron ore. m m m •Sii it. \'\ 15G ACIDS IIMI'KIIFECTI.Y EXAMINED, I 1,i '•■ I ■ ill . !l wi 11 t m SECTION IV. — OF PUTEANIC ACID. This acid was discovered, in 1835, by M. Haenle, apc'^^hecary at Lahr, in the ochre which deposits abundantly in the wells of that neighbourhood. He obtained it in the following manner : — The ochre was boiled in distilled water, in which one-twelfth of its weight of caustic potash had been previously dissolved. The filtered decoction was saturated with acetic acid, added slightly in excess, which disengaged carbonic acid. The puteanic acid was precipitated from this solution by acetate of lead, added as long as a precipitate of an uniform colour appeared. The precipitate was washed, and the lead disengaged from it by sulphuretted hydrogen. The filtered residue was evaporated to dryness in vacuo over sul- phuric acid, Puteanic acid, obtained in this way, possesses the fol- lowing properties : — It is a resinous-looking body, transparent when in thin crusts, having a strong lustre, and a brown colour. It has no smell. Its taste is acid, sharp, and slightly astringent. It is quite insoluble iu absolute alcohol, but dissolves readily in water, and the solution reddens litmus paper. Nitrate of silver throws down a yellowish-brown precipitate, soluble in ammonia. Acetate and subacetate of lead, throw down a yellowish-white, while acetate of copper throws down a whitish-yellow precipitate. The protoxide of iron is soluble in a concentrated solution of this acid ; but the peroxide of iron only dissolves when we add am- monia. When puteanic acid is distilled, it evolves substances containing azote. When we add potash and distil, ammonia is disengaged. When we saturate it with ammonia and evaporate, the greatest part of the alkali is disengaged, and the liquor becomes acid. Puteanic acid is distinguished from crenic : 1. By a deeper colour. 2. By the whitish-yellow precipitate with acetate of cop- per, while crenic acid gives a greenish-white, .'i. By its insolu- bility in absolute alcoh.ol. 4. By tlie nitrate of silver, which, with puteanic acid, gives a brownlsl.-ycUow ])recipitate, which remains unaltered, while the precipitate, with crenic acid, soon changes into a reddish-purple. It is distinguished from apocrcnic acid: I. By its sharp acid taste, while that of apocrcnic acid is purely astringent. 2, By its solubility in water. The apocrcnic acid is very little soluble in that liquid. ;J. By its insolubility in absolute alcohol — apocrcnic acid being more soluble in absolute alcohol than in water. 4. By its aqueous solution not being preci])itatcd by sal annnoniac, while that of apocrcnic acid is prccipitatcil by that salt.* SECTION -OF I'ALMIC ACIU. An account of this acid will be giver in a subsccpient part of this volume, whiU' treating of castor oil. * Ji)ur. ti(> FliHiiiuiric. x.\i. [ilO. 1 STRYCHNIC ACID. 157 acid H\ its 1 that 2 acid h its 10 that It' this SECTION VI. — OF GUMMIC ACID. This cacid was discovered by M. Simonin, about the year 1830, and an account of it published by hira in 1832.* His results were speedily confirmed by M. Guerin-Varry.f Four ounces of gum senega! were dissolved in 6 1 cubic inches, or rather less than three wine pints of water, and a current of chlorine gas was passed through the solution for 48 hours. The liquid, which now contained a great deal of muriatic acid, was mixed with an excess of lime, when it emitted a smell of apples. The precipitate was well washed with water, and then decomposed by dilute sul- phuric acid. Alcohol was added to the liquid, to throw down the whole sulphate of lime. It was then filtered, and evaporated to dryness. What remains is a yellowish solid body, not the least crystalline, and reddening litmus paper. It scarcely attracts moisture from the atmosphere. It has the consistence of soft wax. When incinerated it leaves a little lime. It is very soluble in alcohol of 0*8 17, and also in spirits. The aqueous solution of this acid is precipitated in a fine powder by acetate of lead, in scanty flocks by nitrate of silver, and in bulky flocks by lime and barytes water. These last precipitates are so- luble in nitric acid. W'ith the salifiable bases it forms salts, which do not crystallize. When saturated with carbonate of lime it gives a very soluble salt, according to Simonin, which, when dried, resembles gum, does not attract moisture from the atmosphere, and whose solution is decom- posed by sulphuric acid, which separates the lime. Such are the properties of this acid hitherto ascertained. A more complete investigation would be necessary to determine whether it be a new acid, or a modification of malic acid, to which it bears some resemblance. SECTION VII or IGASUIIIC OH STRYCHNIC ACID. This .acid was discovered by Pelletier and Caventou, in the strychnos nux vomica, strychnos Ignatii, and the strvrhnos colubrina, the same which yield strichnina. It may be extracted by the following process : — Rasp nux vomica^ or St lynatius^ bean, and treat it first with ether, and then with al- cohol. Evaporate the alcoholic solution, mix it with water, filter and digest the liquid with calcined magnesia, which throws down the strychnina, and form with the igasuric acid a salt, insoluble in cold water. The precipitated matter is first washed with cold water, and then boiled in alcohol, till the whole strychnina is dis- solved. The residual matter is now boiled in a great quantity of water, which dissolves the igasuratc of magnesia. This solution is now mixed with acetate of lead. Igasurate of lead precipitates, ', .1,1 'I I ■■: i. t i ■ [A . ^ a Ann. de Chim. ot de Phys. 1. 319. t Ibid. li. 222. 158 ACIDS IMPERFECTLY EXAMINED. f .! I which is washed, and decomposed by a current of sulphuretted hy- drogen gas. The filtered liquor, freed from sulphuretted hydrogen, is an aqueous solution of igasuric acid. When sufficiently concentrated, it constitutes a brown syrup, from which the igasuric acid is gradually deposited in crystalline grains. Its taste is acid, and rough. It dissolves readily in water and in al- cohol, and forms with the alkalies, salts which are very soluble in water and alcohol. With barytes it forms a salt very soluble in water. When the solution is evaporated, the salt is gradually de- posited in spongy vegetations. The salts of iron, mercury, and silver, are neither precipitated nor altered by the igasurate of am- monia. The salts of copper are coloured green by this salt, and a light green precipitate gradually falls, little soluble in water, which Pelletier pxid Caventou consider as characteristic* SECTION VIII. — OF VULPILIN OR VULPINIC ACID. 1 his substance was discovered, in 1831, by M. Bebert, apothe- cary in Charabery, in the evernia vulpina of Achard, or the lichen vulpinus of Linnaeus. t 'j'his plant, which is a native of the South of Europe, is found in great abundance on the trees in the forests of Ausbourg, at the foot of Mount Cenis and the little St. Bernard. This lichen has a yellow colour. It is composed of filamentous expansions, the extreme divisions of which are almost capillary. When shaken it gives out a yellow powder, which occasions sneezing. When treated by MM. Robiquet and Blondeau with alcohol, it lost its colour, while the alcohol had acquired a deep greenish-yellow colour. When the alcohol was evaporated, the solution became muddy, and the same yellow irritating substance was deposited as from the lichen itself. When the liquid is cooled it deposited a great quantity of granular crystals, of a greeni.n-yellow colour, which, when dried by pressure between folds of blotting paper, had a raicacious appearance, mixed with a deep yellowish-green colouring matter. This matter, treated twice successively by ether, was mostly dis- solved. The solution had a deep grass-green colour. Left to spon- taneous evaporation it deposited flat prisms, of a yellow colour, mixed with chlorophylle. The portion of msitter not dissolved by ether had a yellow colour. Boiling alcohol dissolved it, and when left to spon- taneous evaporation, deposited transparent rectangular prisms, of a fine yellow colour. These crystals constitute the vulpilin of Bebert. The alcohol, from which the matter treated with ether had been ob- tained, being evaporated to dryness, and the residue treated with ether as before, more vulpilin was obtained. Vulpilin is transparent, and of a fine lemon-yellow colour, not altered by exposure to the air, melting when heated, and assuming its crystalline state on cooling. It may be volatilized without de- composition. It is not decomposed by concentrated nitric, sulphuric, or muriatic acids. It is but little soluble in cold water, though it * Ann. de Chini. ct de Phys, x. 1C7. t Jour, de Pharm. xvii. 696. VERDIC ACID. 159 from communicates to it a yellow colour. It is very soluble in boiling water, and in hot alcohol, and in ether. The aqutous solution, though evaporated to the consistence of a syrup, does not crystallize. Gelatinous alumina discolours this solution. It is precipitated by acetate of lead, chloride of tin, and the nitrates of mercury. The concentrated acids likewise render it muddy. Wlien heated in a crucible it swells, and is decomposed, giving out carburetted hydrogen, oil, and a little acid water, without any trace of ammonia. Robiquet and Blondeau ascertained that the solution of vulpllin reddens vegetable blues, and that it combines with ammonia forming a salt. It is therefore an acid. It would probably constitute an important yellow dye ; and, indeed, the lichen vulpinus has been already pointed out by Bucholz as a substance employed for dying woollen cloth. i lur, not Isuming lout de- Iphuric, lough it li. 696. SECTION IX. — OF LACTUCIC ACID. This acid was discovered by Pfaff, in the juice of the lactuca virosa. The clarified juice was precipitated by sulphate of copper, or acetate of lead. The precipitate was washed and decomposed by sulphuretted hydrogen. When the filtered liquid was evaporated, the lactucic acid precipitated in colourless crystals. Its taste is strongly acid, and it has a great resemblance to oxalic acid ; but differs from it by forming abundant green precipitates when di'opt into the neutral protosalts of iron, and a brown precipi- tate with sulphate of copper. With magnesia it forms a little soluble salt. Its other properties have not been examined. SECTION X. — OF VERDOUS AND VERDIC ACIDS. Runge discovered an acid to which he gave the name of verdic, because it becomes green when exposed to the air, combined with an excess of base, in various families of plants, namely, the acoracecB, valeriancSf caprifolicB^ umbellifercE^ and plantaginea:. The green colour is induced by the absorption of oxygen. On that account Berzelius calls the colourless acid verdous, and the green acid verdic. The verdous acid may be obtained from the root of the scabiosa siiccisa, after having first dried it, reduced it to powder, and deprived it of its fibres. It is digested in alcohol, as long as any thing is taken up. The alcoholic solution is concentrated, and ether poured into it. The flocks which are precipitated are dissolved in water, and the solution mixed with lead. The precipitate consists of verdite of lead. It is decomposed by sulphuretted hydrogen. The filtered liquid being evaporated, we obtain the verdous acid under the form of a yellow brittle matter which reddens the infusion of litmus, and undeigoes no alteration when exposed to the air. When this acid is saturated with an alkali, ammonia for example, and exposed to the air, it absorbs oxygen, and gradually assumes a green colour. When thus altered, acids throw it down from its solutions under ' Jii I'j ;.r m ^: ii 1 ('■] 160 ACIDS IMPKIIFECTLY EXAMINED. 1 fl ii ;I;J : II ' the form of a brownish-red powder, which constitutes verdic acid. The alkalies dissolve it, and assume a green colour. The earthy and metalline verdltes are yellow ; but the verdates of the same bases are green. According to llungc, verdous is changed into verdic acid by absorbing an atom of oxygen. SECTION XI. — OF IIHEIN. This substance has been extracted from rhubarb, which is the root of various species of rheum, namely, the palmatum, compactum, australe, et widulatum, and probably even other species. These roots were analyzed with much care by Schradcr, Brande, and Hornemann. The last of these chemists detected in them a peculiar principle, to which he gave the name of rhaponticin. It was ob- tained as follows : — The rhubarb was digested in water till every thing soluble was taki;n up : the aqueous solution was evaporated to the consistence of an extract, and the extract mixed with water. It deposited a yellow i)ulverulent matter, which being washed in cold water, and dissolved in absolute alcohol at a boiling temperature, crystallized, on the cooling of the licjuid, in yellow plates or needles. This substance is destitute of taste and smell, insoluble in cold v,'nter, ether, and volatile oils ; but soluble in 24 times its weight of .;:.: /lute alcohol. It does not act on vegetable colou' s. It has not been analyzed, but appears to contain much azote, and leaves, when calcined, a charcoal difficult to burn.* Vaudin has found, that when ether is digested with rhubarb in powder, it dissolves a reddish-yellow substance, liltle soluble in water, but soluble in alcohol and ether, giving a red colour to the former, and a yellow to the latter. This substance is without smell, but has a slightly bitter taste. Its solutions strike a red colour with alkalies, antl a yellow with acids. Nitric acid does not destroy this substance. If, therefore, we dissolve rhubarb in nitric acid, and evaporate the solution to the consistence of a syrup (which de- stroys the other principles of the root), precipitate the substance with water, and wash it with cold water to free it from the adher- ing acid, we obtain it in a state of purity. Vaudin has given it the name oh-hein.] Its characters have not been determined with accuracy. Dr Carpenter, in 182f), published the following formula for ob- taining rhabarbarin, which he considered as the active principle of rhubarb.l Boil for half an hour six pounds of coarsely bruised Chinese rhubarb in six gallons of water, aciiulated with 'i^ ounces of sulphuric acid ; strain the decoction, and submit the residue to a second ebullition in a similar quantity of acidulated water ; strain * Berzelliis' Traitc de Cliimio, vi. 205. •f- The rhein, rhahnrhnrin, yellow resin, i/elloio matter of different chemists are obviously ditferent iiaiiies for the same substance. The rhabarharine, ca])hoi>i- crite, and bitter principle of rhubarb, are also synonymcs for another substance which exists in riiubarb. X Annals of riiilosophy (Second Scries), xi. 301. : I RHEIN. 161 ; acid. lates of langed 1 is the oactunii These le, and peculiar was ob- ible was isistcnce ositcd a ,ter, and itaUizod, e. in told A'eJirht of t has not es, when nbarb in iluble in lur to the ut smell, id colour t destroy ric acid, bich de- iibstance le adher- cn it the .ccuracy. a for ob- nciple of bruised |l ounces 2sidue to strain liemists are ]?, atphopi- suljstauce as before, and si'bmit it aj^ain to a third ebullition. Unite the three decoctions, and add by small portions recently powdered lime, con- stantly stirring it, to facilitate its action on the Jicid decoction. When the decoction has become slightly alkaline, it deposits a red flocculent precipitate, which is to be separated by passing it through a linen cloth, and dried. After which, reduce it to powder, and digest it in three gallons of alcohol, of the specific gravity 0*837, in a water-bath for several hours, which dissolves the rhabarharin. Se- parate this solution from the calcareous precipitate, and distil off three-fourths of the alcohol. There then remains a strong solution of rhubarb, to which add as much sulphuric acid as will exactly neutralize it, and evaporate the whole slowly to dryness. The resi- duum will be of a brownish-red colour, intermingled with brilliant specks, possessing a pungent styptic taste, soluble in water, and its odour that of native rhubarb. This preparation is stated by Dr Carpenter to be a concentrated form of the active principle of rhubarb. It is of uniform strength, and may be administered safely to new born infants. Brandes has given the following process for obtaining pure rhein. Agitate the powder of rhubarb with ether. liistil off the greatest part of the ether from the solution, and leave the residue to spon- taneous crystallization. Small yellowish-brown crystals are de- posited. Dry them by pressure between folds of paper. Dissolve them in boiling alcohol of 0"856 specific gravity. When the solu- tion cools, most of the crystals are deposited. By repeating these solutions and crystallizations two or three times, the rhein may be obtained in a state of purity.* iMem possesses the following properties : — It is in small grains, which, when dried, assume the foi'm of a powder, having an intense yellow colour. It is destitute of taste and smell, and when dry is not altered by exposure to the air. When heated it melts into a transparent yellow li(iuid ; but if the heat be continued or augmented, it becomes reddish-brown, and is charred without the evolution of any ammonia. It may, however, be sublimed in a yellow smoke, which, when condensed, is a yellow powder, sometimes crystallized. It requires 1 000 times its weight of cold water to dissolve it ; but it is twice as soluble in boiling water. It is very little soluble in alcohol of 0'85() specific gravity. Anhydrous alcohol dissolves jx?*^ part of its weight of it at a boiling temperature, andj^^th when cold. Tliese solutions redden litmus paper. Rhein is slightly soluble in cold oil of turpentine, and oil of al- monds, but more soluble in these liquids while hot. In sulphuric and nitric acid it dissolves with a dark-red colour ; but water throws it down from these acids unaltered. Nitric acid may be distilled off it without procbicing any change. With the saline bases it forms beautiful red compounds. The * Annalen der Pliarinacie, ix. 8j. Rumicin, from rumex patientia, seems the same as rhein. Ibid. p. 810. M |; II ,.:W m 1^ , if. 1 '^ 162 ACIDS rMPERFECTLY EXAMINKI). vfl! r ' J earthy and metalline eonipounils may be formed by double decom- position by means of the compounds of rhein with the alkalies. They are insoluble, and those containinff the metallic oxides differ- ently coloured. The compound of rhein and oxide of copper, for example, is violet. SECTION xii -Ol' I'OLYOALIC ACID. This acid constitutes the peculiar principle of the root of the poll/gala sepega, or rattlesnake root. It was first obtained by ( Jehlen, in a state of impurity? in 1804, and described by him under the name of senegin. M. Quevenne made an elaborate analysis of this root, in 1830, and first showed that its peculiar principle possessed the characters of an acid.* Polygalic acid was obtained by him in the followin<^ way : — The root was pulverized and treated first with cold water and then with boiling water, till every thing soluble in these liquids was taken up. Koth liquids had a reddish-brown colour, strongly reddened litmus paper, and possessed a bitter and pungent taste. Acetate of lead being dro])t into these liquids, a dirty greyish-yellow precipitate fell, which was a compound of the colouring matter of the root with oxide of lead. Through the liquid thus freed from colouring matter, a current of sulphuretted hydrogen gas was pa-'sed, to throw down any excess of lead that might have been added. I^he filtered liquid was now evaporated to dryness. The solid residual matter being treated with alcohol of the sp. gravity 0*8.37, there was left a brown tasteles sraatter, converted by nitric acid into mucic acid, and of course possessing the characters of gum. The alcoholic soluticm being evajiorated, left a brown matter, soluble in water, and having a sharp taste. It was the bitter princi- ple found in senega by PY'neulle. When treated with ether the greatest part of the bitter nuitter was removed ; for after this treat- ment the residue was not bitter, but acrid and jjungent. The extract thus deprived of these foreign matters was dissolved in water, and the solution was mixed with diacetate of lead, which formed a fine yellow precipitate consisting of })olygalic acid luiited to oxide of lead, and not quite free from colouring matter. This precipitate is washed till sulphuretted hydrogen ceases to indicate lead in the washings. It is then mixed with water, and a current of sulphuret- ted hydrogen passed through it to sej)arate the lead. The li((uid is then heated, filtered, and eva])orated to dryness. The dry residue is dissolved in boiling alcohol of 0*837, and filtered while hot. On cooling, a white powder is precij)itated, which is polygalic acid in a state of purity. More of it is obtained by evaporating the alcohol ; and an additional dose by digesting the sulphiiret of lead in alcohol. Polygalic acid, thus obtained, possesses the following characters : — It is a white powder, without smell, and apjjcaring at first taste- less ; but it soon communicates an acrid, pungent feeling to the * .lour, (le Pliarinacio, xxii. 449. POLYGALIC ACID. 163 tlccom- Ikalies. ; ditt'er- per, for , of the Golilen, lie nivinc iiis root, ssed the :_The lien with as taken reddened Lcetate of •ecipitate root with g matter, •ow down red liquid ;ter being 't a brown d, and of n matter, er princi- ethcr the lis treat- le extract ater, and led a fine oxide of ipitate is (I in the idphuret- he liijiiiil y residue lot. On acid in a alcohol ; 1 alcohol. licters : — st taste- |> the solution ether was added as loim' as it i-ontinued to deposit anv sediment. As the litjuid was still coloured, it was agitated witli some bydrati; of lead. From the liipiid, thus rendered eolourlesi, the alcohol and ether were distilled off, and the residue being left to s[)ontaneoua evaporation, deposited corni(^ add in star-shaped crystals. Comic a 1, thus obtained, has a very bitter taste, and is very soluble in water and alcohol. It is soluble also in ether; but less so than in ileohol. Neither ammonia, nor potash, nor lime, pro- duce any change in its acpieous solution. 'I -^ of luitgalls occ;<-;ion9 no alteration. Tincture of iodine d' • '"olour, but no iiidine is separated. It is not altered b\ oj ; 'ad; but subacetate occasions the deposition of a granuhi ' . Corro- sive sublimate occasioned no precipitate ; but niti aio of sdver threw down a white crystalline precipitate;, which was not altered by heat, showing that it contained no aldehydic acid. When comic acid is heated in a platinum spoon it niidts very speedily, then becomes black, giving out a vapour having no smell of ammonia, takes tire and burns with a light name, leaving a very bulky charcoal, which gradually burns away without leaving any I'esidue. When heated with caustic potash in a glass tube it gives out no smell of ammonia ; showing that it contains no a/ote.* Such are the few properties of comic acid determined by Geiger. Farther iuvestigations are wanting before we know anything very precise about its nature and constitution. SECTION XIV. — OF GENTISIN OU GENTISIC ACID. The root of the genliana liitea, under the name of (jenlian, has been long employed in medicine as a bitter; but it was not till 1819 that an attempt was made by M. Henry to ascertain the constitu- ents of this root, and to determine the substan e on which its virtues depend. In 1820, an elaborate analysis of this root was made by MM. Henry and Cavcntou.'*' They extracted a yellow coloured crystallized substance to which they gave the name of gentianin, and to which they ascribed the medicinal cpialities of the root. They describe the mode of obtaining this substance, and give an account of its characters, one of which is, that it has an exceedingly bitter taste. In 1837, M. Lcconte published a very elaborate set of ex periments on gentian.J He found that when the yellow crystals * Geiger found that, when a glass tube, moistened with muriatic acid, was held over the fumes, a few vvhite vapours appeared. But it is not likely that these were owing to ammonia. f Jour, de Pharmacie, vii. 173. % ^^^^- ^*"'- ^'^^' i H*' 1 til.' ' ■ ill '[;■•■' i:! v^!^'^.. IMAGE EVALUATION TEST TARGET (MT-3) /q ^ A^^. ,V4 z 1.0 1.1 150 ^ Ui |2g |25 1^ 12.2 2.0 1.8 1-25 1.4 1.6 ^ 6" ► Hiotographic Sciences Corporation 23 WEST MAIN STREET WEBSTER, N.Y. 14580 (716) 872-4503 in 166 ACIDS IMPERFECTLY EXAMINED. obtained by Henry and Caventou are properly puritied, they lose their bitter taste entirely, and that they possess acid characters, being capable of combining with, and neutralizing bases. On that account he gave it the name of gentisin* or gentisic acid. M. Leconte obtained his gentisin in the following manner: — The root was digested in successive portions of alcohol of 0'825, till every thing soluble in that liquid was taken up. These liquids were mixed, and the alcohol distilled off. The extract was treated with water, which dissolved the bitter extract, sugar, and an acid, and left a white solid oil, mixed with gentisin and some resin. This residue being treated with boiling alcohol of 0'871, the gentisin was dissolved, together with a little resin, and the fatty matter was left behind. Evaporate the alcoholic solution to dryness. Ether will remove any of the fatty matter that may have been dissolved. And by successive solutions and evaporations the gentisin may be rendered quite pure. It amounts to about To\jnt^ V^^^ °^ ^^ ^^^^ employed. It hab a pale yellow colour, is crystallized in long needles, and is exceedingly light. It has a peculiar but weak smell, and is destitute of taste. It has no sensible action on the animal economy. It may be exposed to the air without undergoing any alteration. At 212° it loses no weight, and experiences no change. It is not decomposed though heated to 482°. At 572° it acquires a brownish colour and is not volatili^ied. Cautiously heated over an alcohol lamp, it gives out some yellow vapours which are condensed on the upper part of the tube. It becomes gradually darker coloured, and at last melts, assuming the aspect of an oil. If the heat has not been carried too far, it solidifies on cooling into a brown crystalline substance. It requires 2000 times its weight of cold water to dissolve it, but is rather more soluble in boiling water. Water acidulated with sulphuric, nitric, or muriatic acid, does not dissolve more of it than pure water. But if we add a little potash, soda or ammonia to the water, the liquid assumes a fine yellow colour, and the gentisin dissolves. Cold alcohol dissolves but little of it, but boiling alcohol dissolves its own weight of it, and when the liquid cools the gentisin is de- posited in fine needles. Pure sulphuric ether is hardly a better solvent than water of gentisin. The alkalies dissolve it without alteration, and form with it crystalline compounds, which Leconte considers as salts. But these compounds are very easily decomposed, showing that gentisin is an exceedingly weak acid. The gentisate of soda may be formed by adding a little caustic soda to water, in which gentisin is suspended. The acid is immediately * From Gentiiis, the nainc of the King of Illyria, after whom the plant was named. Plinii Hist. Nat. lil). xxv. c. 7. Il< AMPELIC ACID. 167 , they lose iharacters, On that ler: — The 0-825, till jse liquids as treated id an acid, sin. This le gentisin natter was js. Ether dissolved, in may be jf the root lies, and is is destitute inomy. It ation. At It is not a brownish an alcohol ised on the loured, and at has not crystalline olve it, but ated with of it than onia to the le gentisin dissolves tisin is de- water of m with it But these itisin is an austic soda amediately e plant was dissolved, and the liquid assumes a fine yellow colour. Being evaporated, it leaves a mass of crystals, which being digested in boiling alcohol, of 0*871 specific gravity, dissolve in part, and are deposited in gold-coloured needles when the liquid cools. When these crystals are heated to 212° they lose 23 per cent, of their weight, and become reddish. At 482° they become brown, without being decomposed. At a red heat they melt and leave carbonate of soda. This salt is much more soluble in water than gentisin ; but water decomposes it, the acid being precipitated, and the soda dissolved. 110 parts of boiling alcohol of 0*871 dissolve 10*3 of the salt. While the same quantity of cold alcohol dissolves 7 parts. Alcohol also decomposes it as well as water. When carbonic acid gas is passed through a solution of this salt, the gentisin is thrown down white ; but it recovers its yellow colour when dried. According to the analysis of M. Leconte, this salt is composed of Gentisic acid .... 54*73 Soda 4*00 Water 17*54 76*27 This would make the atomic weight of gentisic acid, 54*73 ; and the crystals seem to contain 1 5 atoms of water. It is proper to state that the facts ascertained by Leconte, had been observed by Trommsdorf about the same time.* SECTION XV. OF AMPELIC ACID. This acid was obtained by M. Laurent, by means of the oils which he extracted by distillation of bituminous slate. t These oils had a certain resemblance to naphtha. Their boil- ing points varied very much ; the lowest being 176", and the highest 572". The oils whose boiling points lay between 176" and 302" formed ampelic acid when boiled in a retort with concentrated nitric acid. Ampelic acid is colourless, without smell, and almost insoluble in cold water. Boiling water dissolves but little, but alcohol and ether are excellent solvents of it. Litmus paper is slightly reddened by it. Its boiling point is above 500°. If we continue the heat, it sublimes in very minute needles. Nitric acid does not act ol it. Hot concentrated sulphuric acid dissolves it, and water throws it down from this solution. When thrown on burning coals it takes fire, and partly sublimes, giving out a smell similar to that of those bodies which have been azotized by nitric acid. With the alkalies it forms soluble salts. When much diluted, nitric acid throws down the ampelic acid in white flocks. The remaining six acids belonging to this order are the follow- ing :_ • Jour, de Pharmacie, xxiii. 479, f Ann. dc Chim. et de Phys. Ixiv. 321. Ill 168 COMPOUND AGIOS. 1 Fungic acid. 4 Crameric. 2 Laccic. 5 Boletic. 3 Solanic. (i Ccvaetic. These acids have been already noticed in the Chemistry of Inor- ganic Bodies (vol. ii. pp. 82, 83, 84, 107, 112, and 139), and nothing can be added to the imperfect description drawn up six years ago. CHAPTER VI. COMPOUND ACIDS. It has been already stated that these acids consist of a vegetable principle, united to a strong mineral or vegetable acid. They may be divided into two sets. The first set consists of two atoms of an acid, combined with one atom of a base, which may be driven off by a stronger base. They are, strictly speaking, not acids, but acidulous or supersalts. The second set contains hyposulphuric acid, combined with an organic substance, not acting the part of a base, and not capable of being expelled by a stronger base. The following table exhibits the names and constitution of these acids, as far as it has been ascertained : — I. Supersalts. 1 Althionic . 2 Oxalovinic 3 Tartrovinic 4 Racemovinic 5 Sulphomethylic . 6 Tartromethylic ,. 7 Racemomethylic . 8 Phosphovinic 9 Arseniovinic 10 Camphovinic 2 (S 03) + C* H« O + H O 2 (C^ O^) + C* H« O + H O 2 (C* H^ 0») + C* H** O + H O 2 (C* W 0») + C* H'^ O + H O 2(S O^) + C' H^ O + H O? 2 (C* H^ 0«) + C^ H' O 2 (C* W 05) + C2 H^ O + H O 2 (Ph O^O + C* W O 2 (Ars 024) + 2 (C* H* O) 2 (C»<» m* O") + C* H» O + H O II. Compound acids containing an acid, combined with an or- ganic substance, not acting the part of a base, and not capable of being expelled by a stronger base. 1 Ethionic . . S^ O'^ + C* H* O + H O 2 Sulphonaphthalic . S^ 0« + C"" H' 3 Hyposulphonaphthalic 2 (S O^) + C" H" 4 Benzosulphuric . S^ O^ + (C^* H< O^) 5 Sulphocetic . S^ O** ? + (C«* W^) + 2 (H O) 6 Sulphoglyceric . S^ O'*? + (C« H^ O^ 7 Sulphoindigotic and hyposulphoindigotic 8 Stearin , Stearic "acid. Glycerin. 2 (C'*" H''^* 0'«)+C« H^ OH 2(H O) ALTHIONIC ACID. 169 rf Jnor- }), and up six jjietable ley may Ltoms of riven off ids, but ulphuric )art of a e. The se acids, ) H O H O ? H (> H O th an 01- apable of ^0) 1-2(H0) 9 Olein . 10 Vegetosulphuric 11 Hyponitromeconic 12 Xanthic 13 Hydrocarbosulphuric Oleic arid. 2 (C" H^"* 0'^i)+ C" IP (>''+2(H0) J (Az 0<) + C'« IF O^ 2 (C S'O + C* H° O + II O C S'-* + H S I. SET. SECTION I. — OF ALTHIONIC ACID. This name has been given by Magnus, to what was formerly called sulphovinic acid: and I am disposed to adopt it, for the reasons assigned in the preface to the Chemistry of Inorganic Bodies. Since the account of this acid in the Chemistry of Inorganic Bodies (vol. ii. p. 170) was drawn up, additional experiments on it have been made, chiefly by Wbhler and Liebig,t Magnus,$ and Mar- chand.§ The. principal object of these experiments, was to de- termine the composition of the acid, and particularly, whether water entered into it as an essential ingredient. It seems to be proved by the experiments of Magnus, that when equal weights of concen- trated sulphuric acid and absolute alcohol are mixed together, one- half of the acid deprives the other half of all its water, while every two atoms of the anhydrous acid thus formed unites with C* H' O -I- H O (or alcohol). Suppose four atoms of concentrated sulphuric acid : — This acid, as is well known, is composed of 1 atom acid + 1 atom water ; so that the four atoms of it contain 4 atoms acid -j- 4 atoms water. They are resolved into 2 (S O^*) + 4 (H O) and 2 (S O'). Now these 2 (S O") unite with (C* H« O + H O). Hence, the com- position of althionic acid is represented by the formula 2 ( S O^) + (C* W + HO). Half the acid employed, therefore, goes to the formation of althi- onic acid. Now, C* H® O is ether, which acts the part of a base. Hence, althionic acid is, in reality, a bisalt, or a bisulphate of ether. The althionates have been hitherto so imperfectly examined, that it would be improper to omit in this place, the few facts which have been ascertained since the Chemistry of Inorganic Bodies was published. All the althionates are, in reality, double salts. They are soluble in water, and many of them are soluble also in alcohol. In general, they form large crystals, though some of them only crystallize in scales. The alkaline althionates are decomposed when heated to 392°. Water is disengaged, together with sulphurous acid, a little carbonic acid, and an oil, which SeruUas considers as identical with * A contraction of alcoholthionic, from hiav, sulphur, and alcohol, as being a compound of sulphuric acid and absolute alcoiiol. tA.nn.deChini.etde Phys. xlvii. 421; and Annaleii der Pharmacic, i. 37. X Ibid. lii. 139. § Pog-gendorf's Annalen, xxxii. 454'. ii lf£! 4 170 COMPOUND ACIDS. heavy oil of wine, but its nature has not yet been fully examined. There remains in the retort an alkaline sulphate, mixed with char- coal. I. Althionate of ammonia. This salt is easily obtained, by adding carbonate of ammonia to a solution of althionate of barytes or lead, till the whole of these bases is precipitated, and then con- centrating the solution. It forms large transparent crystals, but so irregular, that their shape has not been made out. They are not altered by exposure to the air, and are very soluble in water, and less so in alcohol and ether ; so that these liquids throw down the salt from an aqueous solution. Althionate of ammonia has a peculiarly bitter, saline, and cooling taste. It melts at 122°, and, when free from sulphate of ammonia, does not undergo decomposition till heated up to 226°. This is the more surprising, as most of the althionates are decomposed at a lower temperature, and none of them can be fused without altera- tion. This salt, when melted, gives off no water, and undergoes no alteration in its weight. At 226° it gives off alcohol, which is neither mixed with oil of wine, nor with sulphuric acid. Towards the end of the process the smell of ether becomes perceptible, and this salt increases as the heat is raised. At last sulphuric acid is given off, and finally every thing vanishes from the retort, except a small quantity of charcoal.* 2. Althionate of potash crystallizes in scales having a pearly lustre, and resembling boracic acid. It has a soapy feel and a bitter taste. It is very soluble in water, and undergoes little altera- tion when exposed to the air. When heated it melts, gives off in- flammable vapour, and leaves sulphate of potash. Its constituents are 2 atoms sulphuric acid 1 atom potash I atom ether 10 6 4-625 20'625-j- 3. Althionate of soda crystallizes in rectangular prisms, which effloresce in the air. It is very bitter, dissolves in twice its weight of cold, and in its own weight of boiling water. It is composed of 2 atoms sulphuric acid . . 10 I atom soda .... 4 1 atom ether . . . 4*625 2 atoms water . . . 2*25 c< o h, lo gi b( of Pt si] ta an i \ i \ 20-875 4. Althionate of barytes crystallizes in beautiful square tables, not altered in the air, but which lose, in vacuo, 4*3 per cent, of * Marchand, PosgendorPs Annalcn, xxviii. 233. f Dumas, Chiniie appliquee aux Arts, v. 534. Tlic analysis was made by Mr Hennell, and confirmed by Murchand. It i • i amined. th cbar- ned, by • barytes hen con- s, but so J are not .ter, and lown tbe d cooling immonia, This is losed at a ut altera- indergoes which is Towards tible, and ric acid is »rt, except a pearly eel and a ttle altcra- ves off in- nstituents which [its weight tnposed of lare tables, ler cent, of made by Mr ALTHIONIC ACID. 171 water. It is very soluble in water, but scarcely soluble in absolute alcohol. When distilled, it gives out sulphurous acid, enipyreu- matic water, and heavy oil of wine. Liebig analyzed it with great care, and determined its composi- tion to be 2 atoms sulphuric acid . 10 1 atom barytes . . . 9*5 1 atom ether . . . 4'<)25 2 atoms water . . . 2*25 2(i-375* When dried in vacuo, it loses two atoms water.f What re- mains is two atoms sulphuric acid, one atom barytes, and one atom ether. 5. Althionate of lime was analyzed by Marchand, who found it composed of 2 atoms sulphuric acid . . 10 I atom lime .... 3*5 1 atom ether . . . 4*625 2 atoms water . . . 2* 25 20-375t 6. Althionate of iron. Althionic acid dissolves iron with effer- vescence, and the disengagement of hydrogen gas. The solution is colourless, has a sweetish taste, and is not precipitated by chloride of barium. By spontaneous evaporation we obtain four-sided prisms, having a yellowish-white colour. They effloresce in the air, and lose their transparency. § 7. Althionate of lead. In addition to the account of this salt, given in the Chemistry of Inorganic Bodies (vol. ii. p. 051), it may be mentioned that it is very deliquescent, absorbing such a quantity of moisture as to be converted into a liquid, by a few hours' ex- posure to the atmosphere. Dumas and BouUay obtained althionate of lead crystallized in silky needles, while Vogel affirms that it is incapable of being crys- tallized. 8. Althionate of copper. This salt, from the analysis of Dumas and Boullay, seems to be composed of 2 atoms sulphuric acid . . 10 1 atom oxide of copper . . 5 1 atom ether . . . 4*625 2 atoms water . . . 2*25 21*875 * Animlen der Pliarmacic, xiii. 27. + Magnus, Ann. de Chini. ct de Phys. Hi. 1.53. :j: Poggcndorf, xxxii. 436. ^ Dumas, Chimic applicjuee anx Arts, v. 337 ■ m 172 i ! COMl'OUNI) ACIUS. SECTION II. — OF OXALOVINIC ACID. This acid wus discovorctl by Mitscherlich,* and liitiierto it has been but iinperfectly investigated. The method of prepariiijj it is as follows : — Oxalic ether is dissolved in absolute alcohol, and a solution of potash in absolute alcohol is added, precisely sufficient to saturate half the acid contained in the ether. A salt soon precipitates in crystalline scales, almost insoluble in absolute alcohol. This salt is oxalovinate of potash. It dissolves readily in water, but there is some difficulty in obtaining it in crystals from its aqueous solution. An excess of base converts it into oxalate and alcohol ; just us would happen to oxalic ether itself. It undergoes no change at the temperature of 212°. Its constitu- ents are 1 atom potash ... (J 2 atoms oxalic acid ... 9 1 atom ether . . 4*625 19^25 To obtain oxalovinic acid the oxalovinate of potash is dissolved in weak alcohol, and the solution filtered. Sulphuric acid being cau- tiously added in the requisite quantity, sulphate of potash is deposited and oxalovinic acid remains in solution. It decomposes carbonates of barytes and lime, forming soluble oxalovinates capable of crystallizing. From oxalovinate of barytes it is easy to obtain pure oxalovinic acid. Several bases, oxide of copper, for example, when placed in con- tact with this acid, decompose it, and oxalate of copper is formed. The same thing happens when we digest oxalovinate of potash with sulphates of copper, manganese, cobalt and zinc, or acf.tate of lead. Oxalates of these bases are formed. When oxalovina*"** cf potash is boiled with any salt of lime oxalate of lime is formed. When we concentrate a solution of oxalovinic acid either on the sand-bath, or in vacuo, we obtain for residue puye oxalic acid. When we dissolve oxalic ether in alcohol and add to it ammonia by little and little, till a little oxamide begins to precipitate under the form of a white powder, the liquor thus prepared gives bulky crystals of a new substance. While the oxalovinate of potash is decomposed by boiling it with acetate of lead, oxalate of lead being formed, this new substance pro- duces nothing similar. Its constituents, according to Mitscherlich, are {) atoms carbon . . = 4*5 4^ atoms hydrogen . . = 0*5625 1 atom azote . . . =1-75 2 atoms oxygen . . = 2*00 4-8125 This remarkable substance requires further investigation. * Lehrbucli, p. 644. TAmnoviNic Acm. 173 to it lias •iug it is lution ol" saturate jitatcs in liis salt is tliere is solution. ; just us coiistitu- ssolved in jeing cau- I deposited ng soluble of barytes ed in con- is formed, otash with te of lead, f potash is ler on the acid. ammonia ;ate under lives bulky tng it with \tance pro- [erlich, are SECTION III. — 01- TAUTllOVINIC ACID. This acid has been recently discovered and described by M. Guerin-Varry.* Trommsdorf observed lonj^ajro, that when tartaric acid was dissolv- ed is absolute alcohol by the assistance of heat, the liquor, though concentrated, did not deposit crystals of tartaric acid. When this liquid was saturated with carbonate of lime tartrate of lime was ob- tained, and a liquid containing tartaric acid, alcohol and lime. It was the knowledge of this fact that led M. Guerin- Varry to investi- gate the subject farther. He dissolved tartaric acid in powder in its own weight of boiling alcohol, and kept the solution for six hours at a temperature of between 150" and 160°. The syrupy mass was then divided into two parts. The first was diluted with a great deal of water to see whether any tartaric ether would be separated ; but none appeared. The other portion was mixed with four times its bulk of water and saturated with carbonate of barytes in a gentle heat. Tartrate of barytes precipitated, which was separated by the filter. The liquid being concentrated and filtered at about 120°, to get rid of some more tartrate of barytes which had precipitated, was left to spon- taneous evaporation. It gradually deposited beautiful crystals of tartrovinate of barytes. To obtain tartrovinic acid from these crystals we have only to dissolve them in water, and to add to the solution the quantity of sulphuric acid requisite to saturate exactly the barytes which they contain. The liquid must be filtered and evaporated in vacuo, till the solid and crystalline residue undergoes no farther loss. Tartrovinic acid, thus obtained, has a fine white colour, is desti- tute of smell, and has a sweetish and agreeable acidulous taste. It crystallizes in long oblique four-sided prisms, is heavier than water, and speedily absorbs moisture from the atmosphere. It dissolves readily in water and alcohol, but is insoluble in ether. It burns with a flame similar to that of alcohol, giving out the same smell as tartaric acid does under similar circumstances. When kept boiling for ten hours with 40 times its weight of water, it is decomposed entirely into alcohol and tartaric acid, which is de- posited in beautiful crystals. When exposed to heat it softens at 86°, and becomes more and more moist as the heat increases, and at 194° it is a thick syrup. The liquidity augments to 284", when it begins to give oft' vapours. At 329° they are disengaged in such quantity that the liquid appears to be boiling. At this time alcohol, water, acetic ether, acetic acid, carbonic acid, and carburetted hydrogen are disengaged, and may be collected. At 356" the retort contains an acid having consider- able analogy to that which M. Braconnot obtained by exposing tar- taric acid, for an instant, to a strong heat. At 392°, besides the * Ann. de Chim. et de Phvs. Ixii. 57. f.\ ^sa V! ll m I m 174 COMPOUND ACIDS. nbove-mcntioncil products, ii voliitilo oil roined over, and u liquid very similar to jicctone. Tiiero rcinaina in the retort charcoal, nyrotartaric acid, and un oily matter. A dilute solution of tartrovinic acid, when left exposed to an atmoHphere of 77°, lets fall some mucus, and a syrup containing crystals of tartrovinic acid. Tartrovinic acid dissolves in nitric acid of specific gravity I'.'J. After an hour's solution, red vapours are given off. If we now ap])ly heat we obtain acetic acid, carbonic acid, and crystals of oxalic acid. Sulphuric acid dissolves it completely without the discngjiii'e- ment of any gas. When the solution is heated there are given off acetic, carbonic, and sulphurous acids, together with carburetted hydrogen and traces of sweet oil of wine. Iron and zinc are dissolved by this acid with the disengagement of hydrogen ; but it has no action on tin, even when assisted by heat. When an aqueous solution of tartrovinic acid is let fall, drop by drop, into barv' water, a precipitate falls, which diminishes in proportion as t1 liquid approaches neutrality, and when the acid is once added in i\cess the precipitate disappears and the liquid be- comes transparent. This is directly contrary to what happens when we employ tartaric acid. This acid does not occasion any precipitate in strontian water. With lime water it throws down a precipitate which disappears with an excess of acid. No precipitate appears when it is added to potash or soda, whatever be tlie state of the liquid. With acetate of lead it deposits small prisms, soluble in tartro- vinic acid. When these crystals are dried they have a pearly lustre and a fine white colour. With concentrated nitrate of silver it throws down a precipitate insoluble in an excess of the acid. These characters allow us to distinguish it readily from tartaric acid. M. Guerin-Varry subjected this acid to an analysis with oxide of i'opper, and obtained Carbon 40*35 or 12 atoms =9 or per cent. 40*45 Hydrogen 5*74 or 10 atoms = 1*25 — — 5*()1 Oxygen 53*£ 1 or 12 atoms : = 12 - 53*94 22*25 100*00 These atoms are resolvable into 2 atoms tartaric acid • C8 H^ QIO 1 atom ether , C* W o 1 atom water • H o C'2 W O'' It is therefore a compound of 2 atoms of tartaric acid with 1 atom of ether and 1 atom of water. All the tartrovinates are soluble in water and little soluble in strong alcohol ; but they dissolve readily in dilute alcohol. They in general crystallize easily. Most of them have a soapy feel, and thev burn with a flame like that of alcohol. TAUTUOVINU ACID. I7r> charcoal, s('(l to an [•ontaining ravity l*Ii. now apply I of oxalic (Uscujiiii'e- ^ivcn off ;arl)uretted ingagement ;c(l by lieat. ill, drop by niinisbea in 1 the acid is e liquid be- lat bappens ccasion any •ows down a ) precipitate I the state of lie in tartro- pcarly lustre of silver it ;id. These ic acid. ith oxide of 40-45 5-()l 63-94 100-00 with I atom le soluble in 3bol. They ipy feel, and Tho alkaline tnrtroviimtoa, when oy,)()rted to the action of heat, melt between IJH.'i" and 4l!)°. Tlicy are deconinosed when heated a few deirrees above this last tenipcraturo. VVlien tluis destroyed they yield water, alcohol, acetic ether, acetic acid, a little volatile oil, carbonic acid, and carl)uretted hydrogen. There remains in the retort charcoal and a pyrotartrate, unless the heat has been raised too high. When their aqueous solution is kept long boiling they are resolved into alcohol and i)itartrates. When treated with an alkali at a tem- Eerature between 320" and 338**, alcohol, acetic ether, and a very itter-tasted oily looking substance are disengaged. The tartrovinates may b(( prepared either by means of tartaric acid, alcohol and a carbonate, or by double tlecomposition. All those hitherto examined contain water of crystallization, except the tartrovinatc of silver, which is anhydrous. 1. Tartrovinate of ammonia may be obtained by neutralizing tar- trovinic acid by carbonate of ammonia, and abandoning the solution to spontaneous crystallization. It crystallizes in silky fibres, seem- ingly very long oblique four-sided prisms. 2. Tartrovinate. of potash may be obtained by decomposing tartro- vinate of barytes by sulphate of potash in slight excess. The liquid, filtered and evaporated to the consistence of a syruj), and treated with alcohol to precipitate the sulphate of potash which it contains, is to be filtered anew, and then left to spontaneous crystallization. This salt is white and has no smell. Its taste is very slightly bitter. It crystallizes in oblique prisms with angles of 124° and 5()°. The acute edge of the prism is usually truncated, and the base is inclined to that edge at an angle of 1 12° 30'. 100 parts of water at 74" dissolve 105-83, and at a boiling tem- perature any quantity whatever of this salt. It is insoluble, when cold, in alcohol and pvroxylic spirit, foiling absolute alcohol dis- solves only a trace of it. It softens at 302°, and melts at 401°. An aqueous solution of this salt exposed to the action of a gentle heat, and in contact with the atmosphere, allows bitartrate of potash to precipitate, while alcohol makes its appearance in the liquid. The precipitate is increased by long-continued boiling. It was carefully analyzed by M. Guerin-Varry. He obtained Carbon 32-20 or 12 atoms = 9 Hydrogen 4-44 or 10 atoms = 1-25 Oxygen 42-58 or 12 atoms = 12 Potash 20-78 or 1 atom = 6 100-00 28-25 Or 1 atom tartrovinic acid united to 1 atom of potash. Tartrovinic acid forms also a subsalt with potash, which possesses alkaline characters, and crystallizes in eight-sided prisms, terminated probably by an oblique base. 3. Tartrovinate of soda may be prepared in the same way as the tartrovinate of potash. I 17<5 COMTOimi) ACIDH. It is wliitp, crystulli/cii in plutes, »uinutitnus rliumbuiilul unil etutiiu- timcs nu'tiui^fiiliir. It in composed o( I iitoiii tartroviiiic acid . . *i'2'25 1 atom sodii ... 4 2J ntoiiw wuter . . . '2'H\'2r> 2!>-0()25 4. Tnrtrnvinntc of hnrytea crvHtallizcs in ohrKpio rliomlioidal |)risins. It is white, Im.s no sujell, and its taste is slii^litly Ititter. 100 parts of water at T.\° dissolve :JH'I2, at 212° 127'2°. It gives out, when in fusion, an odoiu" of alcohol and ether. It is composed of 1 atom tartrovinie acid . . 22*2r> 1 atom liarytes . . . \)'b I atom water . . . l"125 When dried in vacuo it gives out two atoms water. Hence thetar- Hrovinic acid nuist lo«e the atom of water which it usually contains, 5. Tartrovinate of lime. Pr«![)ared in the same May as tartrovin- ate of harytes. It crystallizcjs in white rectangular prisms or plates. At 212° it undergoes the watery fusion, and at 410*^ the igneous fusion. It is composed of 1 atom tartrovinie acid . . 22*25 1 atom lime .... ,')'5() 5 atoms water . . . 5-()2;> 31 -.37/5 6. Tartrmnnate of zinc. Obtained by dissolving zinc with the assistance of heat in dilute tartrovinie acid. It is white, has a very soapy feel, and crystallizes in rectangular prisms, usually occurring in groups. 7. Scsfjnitartroviuatc of copper. Formed by dissolving black oxide of cop])er in tartrovinie acid by means of a gentle heat. It has a bbic colour, effloresces when exj)osed to the atmosphere, and crys- tallizes in long silky needles. It contains (j atoms of water. 8. Tartrovinate of silver. It is preparcnl by ])ourn)g a concen- trated solution of nitrate of silver into an ecpially concentrated solu- tion of tartrovinate of barytes or potash, taking care that an exces.s of the latter salt slioidd be present. A multitude of jn-isniatic crys- tals precipitate. They should be dried in a dark j)lace, and washed with cold water. They should then be exposed to a tcmi)craturo not exceeding 122°. This salt is white, and crystallizes in prisms, often bulging out in the centre. It is but slightly soluble in cold water. When exposed to the light, the colour becomes tirst red, which gradually darkens RACUMOVINIC ACID. 177 rtomo- inho'ulul I'ltttT. i-l \mrtH irit. It i the tar- conta'ms. ;artn)vin- or ^)lllteI4. > igncoua with the Ictangular lack oxide It has a mil crys- jr. la conccn- jitcd sohi- lan excess latic crys- |i(l washed I'ature not hig out in In exposed darkens into brown. At 212* it underf(oes ducotnpodition, whether heated l»y itself or in contact with water. It \» unhydrouM, and waH found hy M. (tucrin-Varry composed of Tartrovinic acid rij)'47 or 21'27 Oxide of silver . 40*5.3orfi4'l lUO-00 Thirt analysis makes the atomic weijj^ht of tartrovinic acid a little less than the theoretic nundier. Henco it is prohahle that, like turtovinate of barytes, it wants the atom of water which usually exists in tartrovinic acid. This would reduce the atomic weight to 21-12.'), which agrees very nearly with the constitution of tartrovinate of silver. SECTION IV. — OF IIACKMOVINIC ACID. For the knowledge of this ii'id, also, we are indebted to M. Guerin- Varry, who, after the discovery of tartrovinic acid, was naturally led to examine the action of racemic acid, which has the same com- position with tartaric acid (if we abstract the water), upon alcohol, and the result was the discovery of racemovinic acid.* Kacemic acid being but little soluble in absolute alcohol, we mutt employ four parts of alcohol for one of acid. This solution w^ nuist boil slowly, takinjjf care to pour it back into the retort when it passes into the receiver. We may stop the boiling when the liquid, after being brought to the state of a syrup, does not deposit any crystals on cooling. It is then to bo diluted with water, and saturated with carbonate of barytes. The filtered rujuid is to be concentrated in a temperature between 122° and 140°, and then left at rest. The racemovinate of barytes crystallizes. The crystals are easily de- composed by means of sulphuric acid, and racemovinic acid obtained in solution. It crystallizes when the liquid is properly concentrated. Racemovinic acid thus obtained is white, without smell, and has rather a sweeter taste, than tartrovinic acid. Its crystals are very similar to those of tartrovinic acid, except that the base of the crystals of the latter acid is more inclined to the axis of the prism. The crystals are snmll and deliquescent. Its relations to water, alcohol, and ether, are similar to those of tartrovinic acid. It burns also in the same way as that acid. When kept boiling in 40 times its weight of water, it is decomposed into alcohol and racemic acid, which crystallizes. Heat, sulphuric and nitric acids, zinc, iron, and tin, act upon it, as upon tartrovinic acid. Its action on barytes water is also the same. Lime water occasions a precipitate, insoluble in an excess of racemovinic acid and water, but soluble in nitric acid. With strontian water a precipitate falls, soluble in an excess of the acid. With potash a pulverulent precipitate falls, which is very fine if there be an excess of acid present. In soda it produces an opaline precipitate, which appears a little before the liquid becomes neutral, and increases with * Ann. dc Cliim. et dc Phys. Ixii. 70. N il 178 COMPOUND ACIDS. I ■! ' :i m ■■ I ! I \ the quantity of acid. This precipitate is insoluble in cold water. The phenomena are the same when carbonate of soda is used. When dropt into solutions of sulphate of lime, or sulphate of soda, it occasions no precipitate even after an interval of 24 hours. It precipitates acetate of lead white, and throws down a white precipitate when dropt into a concentrated solution of nitrate of silver. This last precipitate is in prisms similar to those of tartro- vinate of silver. When analyzed by oxide of copper, it gave Carbon 38*655 or 12 atoms =9 or per cent. 38'50 Hydrogen 5-925 or 1 1 atoms = 1-375 — — 5-88 Oxygen 55-420 or 13 atoms =13 — — 55-()2 100-000 23-375 100-00 These atomic numbers obviously resolve themselves into 2 atoms racemic acid . . C^ H* O"* 1 atom ether . . . C* H^ O 2 atoms water ... H^ 0» QU H" 0'» Thus it differs from tartrovinic acid by containing an additional atom of water. The remarks made in the last section on the tartrovinates apply pretty accurately to the racemovinates. It may be observed, how- ever, that racemovinates do not by any means crystallize so regu- larly as the tartrovinates. Several of them contain more water than the corresponding tartrovinates, but this water maybe dissipated by drying them in vacuo, over sulphuric acid. 1 . Racemovinate of potash may be prepared in the same way as the tartrovinate of potash. It is white, and has the same taste as the tartrovinate of potash ; but it does not crystallize so well. The crystals are rectangular prisms, with square bases, having the edges of the base replaced by very oblique faces. When dried in vacuo it loses 7-65 per cent, of water. Its constituents are 1 atom racemovinic acid . . 21*125 1 atom potash .... 6 2 atoms water . . . .2*25 29-375 2. Racemovinate ofbarytes is white, and crystallizes in very small prisms concreted into tubercles. It is much more soluble in hot than in cold water. It is insoluble in alcohol and pyroxylic spirit. It is composed of 1 atom racemovinic acid . .21-125 1 atom barytes . . . 9-5 2 atoms water . . .2-25 32-875 SULPHOMBTHYLIC ACID. 179 ater. soda, white ite of artro- 50 88 62 •00 ( ditioTial !s apply d, how- 50 regu- ter than )atedby way as potash ; ;angular aced by cent, of fry small in hot ic spirit. 3: Racemovinate of silver may be obtained in the same way as the tartrovinate of silver, and agrees with that salt in all its pro- perties. Its constitution is also the same : for it is composed of 1 atom racemovinic acid . . 21*125 1 atom oxide of silver . . 14'5 35-625 SECTION V. — OF SULPHOMBTHYLIC ACID. The easiest method of obtaining this acid is from sulphomethylate of barytes, which may be prepared in the following way : — Add, by small quantities at a time, one part of pyroxylic spirit to two parts of concentrated sulphuric acid. Much heat is evolved, and the liquid contains sulphomethylic acid. To this liquid add a slight excess of barytes, filter to get rid of the sulphate of barytes, which precipitates, then pass a current of carbonic acid through the liquid, to throw down any uncombined barytes which may be present, and filter again. When this liquid is concentrated on the vapour- bath to the proper consistency, and placed under the vacuum of an air-pump, along with some quicklime, it crystallizes to the very last drop in beautiful square plates. This salt is colourless, has a cooling tasie, and effloresces when exposed to the air. It effloresces still more rapidly in vacuo, and becomes quite opaque. When heated it decrepitates, and effloresces without melting. A stronger heat disengages sulphurous acid, an inflammable gas, water, and neutral sulphate of methylene. Sul- phate of barytes remains coloured by some particles of charcoal. When heated in an open vessel it takes fire, and leaves pure sulphate of barytes behind it. its constituents, as determined by the analysis of Dumas and Peligot, are Sulphate of barytes . . 58*5 Sulphuric acid Carbon Hydrogen Water Loss (oxygen) 20-8 602 1-5 10-013 96-833 3-167 100-000 It is bbvious that the organic matter in this salt is composed of Carbon 6-02 or per cent. 56-33 Hydrogen 1*5 — — 14*03 Oxygen 3*167 — — 29-64 These numbers approach 100 i i4 •;i| i f m I ii 'i i' ■ m :i ' 180 r I ii COMPOUND ACiDS. 2 atoms carbon =1*5 or per cent. 52*17 3 atoms hydrogen = 0-375 — ~ 13-06 1 atom oxygen =1- — — 34-77 2-875 100 Now, this is the compound to which Dumas and Peligot have given the name of hydrate of methylene, and which I have consi- dered as methylene. It is clear that the sulphuric acid in this salt is combined, one half of it with barytes, and the other half of it with methylene. We may represent the constitution thus : — 2 atoms sulphuric acid ■ . 10 1 atom barytes . . . 9-5 1 atcrii methylene • . . 2-875 2 atoms water . . . 2-25 23-825 To obtain sulphomethylic acid from this salt, we have only to dissolve it in water, and to add, by little and little, as much sulphuric acid as will exactly precipitate the whole of the barytes which it contains. We then filter the liquid, and evaporate it spontaneously in vacuo. When it has acquired a syrupy consistency, the sulpho- methylic acid, or bisulphate of methylene crystallizes in white needles. This compound is very easily altered. In vacuo it is rapidly de- stroyed, sulphurous acid being formed. It is very acid. It dis- solves in water with facility, but does not dissolve so well in alcohol. It forms double salts with all the mineral bases ; and these salts are very soluble in water. When these salts, with alkaline bases, are decomposed by heat, they give out the neutral sulphate of methy- lene in great quantity. The double sulphate of barytes and methylene crystallizes with great facility and regularity. That of lime is deliquescent. That of potash crystallizes in pearly plates.* When anhydrous sulphuric acid is made to pass into pyroxylic spirit, if we dilute the liquid with water, and supersaturate with barytes, a peculiar sulphomethylate of barytes will remain in solu- tion. It crystallizes in long slender prisms, having a rhombic base. Yet the composition of this salt is quite the same with that of com- mon sulphomethylate of barytes.f Oxalic, acetic, and benzoic acids, did not form compound acids with methylene.^ SECTION VI. OF TARTROMETHYLIC ACID. This acid was also discovered by M. Guerin- Varry, and described by him in the same paper in which he gave an account of the tar- trovinic and racemovinic acids. § It may be obtained by dissolving, at a boiling temperature, 1 part • Ann. de Chim. el de Phys. Iviii. 54. I Ibid. Ixi. 200. t Ibid. Ixi. 199. § Ibid. Ixii. 77. TAUTROMETHYLIC ACID. isr ot have ! consi- ed, one no. We only to ulphuric which it aneously ; sulpho- I needles, pidly de- It dis- alcohol. salts are ases, are F methy- izes with That [)yroxylic late with in solu- )ic base, of com- id acids lescribed Ithe tar- j, 1 part 1 199. of tartaric acid in 1 nart of pyroxylic spirit, and distilling the liquor to the consistence of a syrun »t a temperature under 212". When we perceive that the di;.J lon goes on slowly, we examine the syrup to ascertain whether 2 . contains tartaric acid. Should any be present, the liquid which has passed into the receiver must be poured back, and the distillation repeated. If no tartaric acid be detected, we dilute the syrup with half its weight of water, and concentrate in a temperature below 212<». We obtain a thick syrup, which, when left to spontaneous evaporation, deposits crystals of tartro- methylic acid ; or more frequently the whole liquor concretes into a crystalline mass, which must be dried in vacuo. Tartromethylic acid is white, destitute of smell, has an acid, but, at the same time, a sweet taste. It is heavier than water, and crystallizes in four-sided prisms, with right bases. It scarcely attracts moisture from the atmosphere. Dissolves readily in cold water, and in any proportion whatever in boiling water. It is soluble also in alcohol and pyroxylic spirit ; but it is very slightly soluble in ether. It burns with a flame, similar to that of pyroxylic spirit. When its aqueous solution is kept boiling, it is decomposed into tartaric acid and pyroxylic spirit ; but is not so easily decomposed by this process as tartrovinic acid. When exposed to the action of heat it melts, then gives out water, pyroxylic spirit, acetate of methylene, and a very heavy liquid, the nature of which has not been determined. When an aqueous solution of tartromethylic acid is exposed to spontaneous evaporation, it deposits crystals of tartromethylic acid. With zinc, iron, and tin, it behaves as tartrovinic acid does. With barytes, strontian, and lime water, it forms precipitates, which dissolve in a slight excess of acid. The precipitate from strontian water dissolves also in water. With potash it forms a pre- cipitate when the liquid is a little acid. But this precipitate is not granular and crystalline as that formed with tartaric acid; it is milky, insoluble in an excess of acid, but soluble in a very large quantity of water. When examined under the microscope no ap- pearance of crystallization can be observed. With soda tartromethylic acid throws down an abundant precipi- tate as soon as the liquid contains an excess of acid. This precipi- tate is granular ; but not crystallized. It is insoluble in an excess of acid, but dissolves in a large quantity of water. Tartromethylic acid does not precipitate sulphate of potash or sulphate of soda. When dropt into acetate of lead it occasions a precipitate at first in flocks, but becoming pulverulent when there is an excess of acid. In this last case there appear flat prisms, dis- posed in the form of stars. With concentrated nitrate of silver it forms a flocky precipitate, insoluble in an excess of acid, and very little soluble in water. It was analyzed by M. Guerin- Varry, by means of oxide of cop- per. He obtained l(f t'5l ?ff I'M? '■ iif ir t ' t 162 ■ I ii! I , ■■• Carbon Hydrogen Oxygen COMPOUND ACIDS. 36'44 or 10 atoms = 7*5 or per cent. 36*58 4-88 or 8 atoms =1-0 — — 4-87 58-68 or 12 atoms =12-0 — — 58-55 100-00 20-5 100-00 Now, it will be shown in a future Chapter of this work, that me- thylene is a compound of C^ H' O. It is obvious that the preceding atomic numbers maybe resolved into 2 atoms tartaric acid . C^ H* 0'° 1 atom methylene . . C H' O 1 atom water . . HO ' ' . '• i: :-. CIO H8 0'2 Thus it appears that tartromethylic acid is composed of 2 atoms tartaric acid . . = 16-50 1 atom methylene . . = 2-875 1 atom water . . . = 1-125 20-500 So that its atomic weight is 20-5. Very few experiments have been made upon the tartr omethylates ; two only of them having been hitherto examined. 1. Tartromethylate of potash may be obtained in the same way as tartrovinate of potash. It is white, has no smell, and crystallizes in right rectangular prisms. It is much more soluble in hot than in cold water. It is insoluble in alcohol and in pyroxylic spirit. When heated it softens at 302°, and becomes yellow. At 338° it gives out white vapours. At 392° it undergoes rapid decompo- sition. Carburetted hydrogen and carbonic acid are given out, and a liquor which contains acetate of methylene, pyroxylic spirit, acetic acid, water, and a syrupy matter. When boiled long in water it is transformed into pyroxylic spirit and bitartrate of potash. When dried in vacuo it loses 4-2 per cent, of its weight in water. Its constituents are 1 atom tartromethylic acid . 19-375 1 atom potash . . . 6- 1 atom water . . . 1-125 26-50 2. Tartromethylate ofharytes. — This salt may be prepared in the same way as tartrovinate of barytes. It is white, has a bitter taste, and crystallizes in right prisms, oc- casionally terminated by bihedral summits. It is insoluble in alcohol and pyroxylic spirit. It is more soluble in hot than in cold water. It is more easily decomposed by boiling its aqueous solution than tartromethylate oi potash. KAdEMOMETHYLIC ACID. 183 jd in the |sras, oc- soluble boiling When raised to a temperature of between 302' and 320", it gives off a syrupy liquid, having an alliaceous smell, and containing water, pyroxylic spirit, acetate of methylene, and a crystallized substance, obtained by evaporation. This substance has not b^en much ex- amined ; but it is not oxalate of methylene. This salt, according to the analysis of Dumas and Peligot, is composed of 1 atom tartromethylic acid . 19'375 1 atom barytes . . . 9*5 1 atom water . . . 1*125 30 SECTION VII OF UACEMOMETHYLIC ACID. For the knowledge of this acid also we are indebted to M. Guerin- Varry, who described its properties in the same paper which con- tains an account of the preceding acids.* It may be obtained in the same way as the tartromethylic, sub- stituting raceraic for tartaric acid. It is white, without smell, and has the same taste as tartromethy- lic acid. It crystallizes in right rectangular prisms, having their lateral edges truncated. Water, alcohol, and ether, act upon it as on tar- tromethylic acid. Boiling water decomposes it into pyroxylic spirit and racemic acid, which crystallizes. But it is more difficult to decompose this acid in this way than it is to decompose tartrovinic and racemovinic acids. When its aqueous solution is left to spon- taneous evaporation no decomposition takes place. It burns with a flame similar to that of pyroxylic spirit. When exposed to the action of heat it gives off the same products as tartromethylic acid. It behaves in the same way as that acid to iron, zinc, and tin. With barytes water it gives a precipitate soluble in an excess of acid. With strontian water the same, but the precipitate is insoluble in an excess of acid. With lime water it gives a precipitate composed of needles. This precipitate is insoluble in an excess of acid. With soda or its carbonate no precipitate. With potash and an excess of acid a precipitate falls soluble in water. Acetate and diacetate of lead are precipitated in flocks insoluble in an excess of acid. With sulphate of potash no precipitate, even after an interval of 16 hours. With a concentrated solution of nitrate of silver a flocky precipi- tate, soluble in an excess of acid. The constituents of this acid, as determined by the analysis of M. Guerin-Varry, are * Aim. tie Chim, et de Phys. Ixii. 83. 1 I m li >% I ill < ' m 1 ti ,1 m i m I u 184 COMPOUND ACIDS. Carbon 34*20 or 10 atoms = 7*5 or per cent. Hydrogen 5'43 or 9 atoms = 1-125 — — Oxygen 60'37 or 13 atoms = 13 — — 34-68 5-20 60-12 100-00 s : 21-625 These are obviously equivalent ta 2 atoms racemic acid ii r. ' C* 1 atom methylene . ' C* 2 atoms water 100-00 H* 0'« H^ O H» 0» CIO PI9 013 Differing from tartromethylic acid only by containing an additional atom of water. 1 . Racemomethylate of potash may be prepared in the same way as the tartrovinate of potash. It is white, and destitute of smell, and crystallizes in rectangular prisms. It is more soluble in hot than in cold water. In alcohol and pyroxylic spirit it is insoluble. When heated, it softens at 2 1 2", and begins to be decomposed at 302°. At 338° the decomposition is more evident, and at 392° the same products are disengaged as from the tartromethylate of potash under the same circumstances. When its aqueous solution is kept long boiling the acid is decomposed into pyroxylic spirit and bitar- trate of potash. When dried in vacuo, it loses a quantity of water equivalent to 4-25 per cent. When subjected to analysis this salt was found to be composed of 1 atom racemomethylic acid . 19*375 1 atom potash ... 6 1 atom water . . . 1-125 26-5 It is therefore exactly the same in its composition as tartromethylate of potash. 2. Racemomethylate of barytes may be prepared in the same way as the tartromethylate of barytes. It is white, and has the same taste with the tartromethylate, crys- tallizes in doubly oblique four-sided prisms. The lateral faces are inclined to each other at angles of 119° and 61°. The base is in- clined to one of the lateral faces at an angle of 87°, and to another at 113°. It contains, when in crystals, four atoms of water : when exposed to the air it loses three of these atoms, becoming opaque, and assuming a satiny lustre. When heated before its efflorescence, it softens at 140°, and at 2 12° gives out vapours, which condense into fine crystalline plates. It melts at 221°, at 248° it boils, at 266° it constitutes a transparent liquid, at 347" it becomes yellow, at 401° the decomposition becomes very conspicuous. The liquid in the receiver contains water, 'f i8 50 [2 [)0 dilional 3 way as tangular I alcohol posed at 392° the )f potash n is kept nd bitar- ivalent to posed of lethylate Jame way ite, crys- Ifaces are lise is in- another exposed ]ue, and Idat2l2° ites. It Itisparent 1 becomes Is water, PHOSPHOVINIC ACID. ■% ♦ 185 acetate of methylene, pyroxylic spirit, and a substance in crystals which is obtained by slow evaporation. When we apply heat to the salt after it has undergone efflores- cence crystals only appear in the upper part of the retort when the temperature has been raised to 266°, and vapours do not escape in any considerable quantity till tl» temperature amounts to 284°. Racemomethylate of bafytes w nore soluble in hot than in cold water. It is insoluble in alcohol and pyroxylic spirit. When the effloresced salt is dried in vacuo it loses a quantity of water, amounting to 3*80 per cent. The constituents of the effloresced salt are ' 1 atom racemomethylic acid 19*375 1 atom barytes ... 9*5 1 atom water . . . 1*125 30 We see from this that when dried in vacuo it loses its atom of water, and becomes anhydrous. These two are the only racemomethylates hitherto examined. > '■'. SECTION Vm. OF PHOSPHOVINIC ACID. * In the year 1807, M. Boullay, senior, showed that an ether, similar to sulphuric ether, could be formed, by distilling a mixture of phosphoric acid and alcohol.* This fact naturally led chemists, after the discovery of althionic acid, to expect the existence of phos- phovinic acid. This suspicion was verified by M. Lassaigne, in 1820. He made a solution of phosphoric acid, of the specific gravity 1*500. This solution was introduced into a retort, and heated to the boiling point. Then alcohol, of 0*817, was let fall into it, drop by drop, till the quantity was equal to that of the acid employed. By repeated distillations he obtained sulphuric ether, mixed with a great deal of alcohol. The viscid residue in the re- tort was dissolved in eight times its weight of water. It was then • saturated with lime, filtered, and rendered neutral. The liquid • contained a soluble salt of lime. He showed that it contained phosphoric acid and the elements of alcohol or ether. He gave it the name oi phospho-vinous acid.f But this name was afterwards changed into phosphovinic acid, as being more systematic. But it was the Memoir of M. Pelouze, published in 1833, which fully explained the formation and characters of this acid, and made us acquainted with its constitution.^ Soon after, the analysis of the phosphovinate of barytes, made by M. Pelouze, was repeated by M. Liebig, who corrected a slight oversight, committed by Pelouze, relating to the water of crystallization contained in the salt, and thus rendered the constitution of the acid more intelligible.§ Phosphovinic acid is prepared in the same way as althionic * Ann. de Chim. Ixii. 192. f Ann. de Chiin. et de Phys. ziii. 294. •■ X Ibid. Hi. 47. § Ibid. liv. 81. • ll Iltl ) in "vl I if k 1 ill ■|ls :'( 111 t n . . 1 186 COMPOUND ACIDS. acid for which the' reader is referred to Section I. of the present Chapter. After having dissolved the phosphovinate of barytes in water, we add to the solution dilute sulphuric acid, by little and little, as long aa it occasions a precipitate. We then filter and concentrate the liquid. After the concentration has been carried to a certain point, we finish the process by placing the concentrated liquid, in vacuo, over sulphuric acid. We obtain a liquid of the consistence of a . thick oil. It cannot be farther concentrjited ; but, if we continue the desiccation in vacuo, it undergoes decomposition, just as hap- pens to althionic acid. Phosphovinic acid may be obtained also by decomposing phosphovinate of lead, by means of sulphuretted hydrogen gas. It has a biting and very acid taste, is destitute of smell, colour- less, and of an oleaginous consistence. It reddens litmus paper. It is soluble in all proportions in water, alcohol, and ether, and may be boiled for a long time without undergoing decomposition, when diluted with two or three times its weight of water. But when as concentrated as possible, if it be made to boil, it undergoes imme- diate decomposition, ether and alcohol pass over, carburetted hydrogen is disengaged, together with traces of sweet oil of wine ; and there remains in the retort, phosphoric acid mixed with charcoal. When a very concentrated solution of this acid is set aside, some crystals are deposited, the quantity of which is not increased, though the liquid be cooled down to — 7°*5. This acid coagulates albumen. No difference has been observed in the acid, whether it be prepared with phosphoric or pyrophos- phoric acid. When dilute phosphovinic acid is placed in contact with zinc or iron, hydrogen gas is disengaged, and phosphovinates of these metals formed. It decomposes the carbonates, driving oif the car- bonic acid gas. Like althionic acid, it contains two atoms of phos- phoric acid, united with an atom of ether, and a quantity of water still undetermined, on account of the difficulty of obtaining the acid in a crystallized state. The only phosphovinates hitherto examined are those of barytes, potash, lime, strontian, lead, and silver, for our knowledge of which we are indebted to M. Pelouze. 1. Phosphovinate of barytes was the salt which M. Pelouze chiefly studied, and by means of which, he determined the composition of phosphovinic acid. To obtain it, we mix equal weights of alcohol of 0*817, and phos- phoric acid of the consistence of a thick syrup, and keep the mix- ture, for some minutes, in a temperature of between 140° and 17C°. After 24 hours we dilute the mixture, with from 7 to 8 times its weight of water, and neutralize it by carbonate of barytes in the state of a fine powder. The liquid is then brought to the state of ebullition, to volatilize the excess of alcohol. It is afterwards al- lowed to cool down to 1.58°, and passed through a filter. The liquid, '.ff*- PHOSPHOVINIC ACin. 187 |)re3ent ter, we as long ate the n point, vacuo, ice of a ■ jontinue as hap- led also liuretted , colour- aper. It and may on, when when as es imme- rburetted of wine ; charcoal, lide, some id, though 1 observed pyrophos- [th zinc or of these Iff the car- ls of phos- of water |r the acid If barytes, |e of which ize chiefly Position of [and phos- tlie mix- land 170°. times its [tes in the \e state of rwards al- rhe liquid. on cooling, dn-osits a fine white salt in hexagonal plates. This is phosphovinate of baiytes. It is white, without smell, and has a disagreeable taste, being saline and bitter at the same time. Wlien exposed to the air it effloresces, but exceedingly slowly. It is insoluble in alcohol and ether, which precipitate it immediately from its solution in water. Its solubility in water is remarkable. It is greatest at about 104°, and dinunishes whether we increase or diminish the tempera- ture of that liquid. M. Pelouze found, that 100 water at 32", dissolves 3-4 of the salt. 41 . 3-3 68 . G-72 104 . ' 9-36 122 . 7-96 131 . 8-89 140 . 8-08 176 . 4-49 212 . 2-80 When heated, the phosphovinate of barytes loses a portion of its water of crystallization, amounting to about 30 per cent, of its weight, and acquires the lustre of mother-of-pearl. It does not be- gin to undergo decomposition till it approaches a red heat. It then gives out water, carburetted hydrogen, and slight traces of alcohol jind ether. The residue is phosphate of barytes, mixed with some charcoal. The primary form of the crystal of this salt is a short right prism, with a rhomboidal base. When cold nitric acid is placed in contac' ;ith it, the colour be- comes opaline ; phosphovinic acid is disengaged, and nitrate of barytes formed. This last salt is easily separated by means of alco- hol, which dissolves the phosphovinic acid, and leaves the nitrate. When this salt is dried, and heated with carbonate of potash, it does not give out alcohol, as is the case with althionate of barytes : it does not undergo decomposition till air '">'=t: red hot : the carbo- nate of potash seems to have no effect in hastening the decomposition. M. Pelouze found, that the crystals of this salt, when dried at 248°, lost 30*575 per cent, of water. M. Liebig, who repeated the experiment, found the loss 29' 15 per cent. He assigns, as the reason of the difference, that the dried salt rapidly attracts mois- ture from the atmosphere. To prevent this, he decomposed the crystals by means of oxide of copper, and calculated the quantity of water of crystallization. M. Pelouze analyzed the dry salt, and obtained Phosphate of barytes . . 82*80 Carbon 9*04 Hydrogen Oxygen 2*26 5*90 100*00 I'.: , 1(1 ft- tyit. 188 COMPOUND A CI OS. M. Liebig,* who analyzod the salt in a crystuUized state, obtained ii ' ! ' Phosphate of bar^te* Water of crystalhzation Carbon Hydrogen Oxygen We may consider it as a compound of 2 atoms phosphate of barytes = 28 1 2 atoms water . . = 13'5 \ 4 atoms carbon = 3 1 atom ether < 5 atoms hydrogen = 0'(i25 1 1 atom oxygen = 1 60-87 29'15 6-43 1-15 2-40 100-00 or per cent. 60-71 — — 29-17 — — 6-59 — — 1-36 — — 2-17 100-00 46-125 It is clear, from this, that phosphovinic acid is a compound of 2 atoms phosphoric acid . . 9 1 atom sulphuric ether . . 4*625 13-625 2. Phosphovinate of potash. All the succeeding phosphovinates are easily obtained, by decomposing phosphovinate of barytes with a corresponding sulphate. Phosphovinate of potash is very difficult to crystallize ; and the crystals are so confused, that their shape has not been made out. It is very deliquescent, and fuses in its water of crystallization. The same observations apply to ihc phosphovinate of soda. 3. Pfiosphovinate of strontian crystallizes with difficulty. Like that of barytes, it is much less soluble in boiling than in warm water. It contains water of crystallization. Alcohol throws it down from its aqueous solution. 4. Phosphovinate of lime. It contains four atoms of water of crystallization. It is very little soluble, and precipitates under the form of smair brilliant micaceous scales, when phosphovinate of barytes is poured into nitrate or muriate of lime. It dissolves readily in water, acidulated by vinegar, or phosphoric acid. 4. Phosphovinate of lead is the most insoluble of all the phospho- vinates. It precipitates in an anhydrous state. 5. Phosphovinate of silver^ in its aspect and little solubility, re- sembles the phosphovinate of lime. It is easily obtained when nitrate of silver and phosphovinate of barytes are mixed together. It contains water of crystallization, though the exact quantity has not been determined. SECTION IX. — ARSENIOVINIC ACID. This acid was discovered, in 1836, by M. Felix d'Arcet, and has been hitherto but imperfectly described. It is formed by causing • Ann. iler Pliannacie, vi. 149. CAMniOVINlC ACID. 189 taincd )0-7l 29-17 6-59 1-36 2-17 00-00 Lof lovinates yies with and the nade out. ,tion. ia. Like m water. Dwn from water of under the vinate of dissolves phospho- )iUty, rc- led when together. ntity has ;, and has ly causing arsenic acid to act on alcoliol, in tlie same way as is followed when phosphovinic acid is prepared. IJy saturating the mixture with carbonate of harytes, filtering and evaporating, we obto'n arsenio- vinate of barytes. This salt, according to the analysis of d'Arcet, is composed of Harium 27-20 Carbon . . . . 19-21 Hydrogen .... 3-3.3 Arsenic .... 15-31 Oxygen .... 34-95 lOO-OO* But he conceives the true constituents to be 1 atom barium 8 atoms carbon 10 atoms hydrogen 2 atoms arsenic 8 atoms oxygen = 8-5 = () = 1-25 = 9-5 = 8 or per cent. 25-56 18-05 3-75 28-57 24-07 33-25 100-00 This would give 1 atom barytes 2 atoms arsenic acid 2 atoms of (C* H" O) or ether. But it is obvious that the results of the analysis are utterly unrecon- cileable to this formula. SECTION X. OF CAMPHOVINIC ACID. M. Malagutti observed that when camphoric acid is boiled with sulphuric acid or muriatic acid and alcohol, we obtain a bitter tasted syrupy substance, which is insoluble in water, but dissolves in alka- line solutions, from which it is precipitated by acids, and which is very soluble in alcohol. This substance, after having been for seve- ral days dried in vacuo, was found by Malagutti to be a compound of C** H^" O^. These numbers may be resolved into 1 atom ether . . C* H» O 1 atom water . . HO And ... . 0^° H'* 0« Now, this last is equivalent to two atoms of anhydrous camphoric acid, so that the syrupy substance is composed of 2 atoms camphoric acid = 22-75 1 atom ether = 4-625 1 atom water =1-125 28-5 This is the reason why M. Malagutti has distinguished it by the name of camphovinic acid.f * Ann. dcr Pharinacie, xix, *J02. f Jour, tic riiarmacic, xxiii. 75. I II 'M !i i ! 190 CUMI'Ol/ND ACIDH. If WO distil it in a rotort, ovor h apirit lamp, wo obtain a butyru- C0OII8 matter, inflammablo ^aHCs, and a roHidiio of oliarcoal. If wo treat the butyraceouH matter with boiling alcoiiol, tho solu- tion on coolinjf deposits very lt»ng crystals, which have neither tasto nor smell, and have no action on vegetable colours. When heated they melt, and may be sublimed without decomposition. Notwith- standing these charactera thoy combine with bases, and form with them crystallizable salts. Their properties are *)! occupy the present. When anhydrous sulphuric acid is made to pass into absolute alcohol and ihe temperature is allowed to rise, sulphurous acid is disengaged, an^^ tho odour of sweet oil of wine is perceived. But Ann. der Pna:>; ncic, yiii. S5. I Aiuv. dr. Lihm . i ,, de Ph;- t JouT. de Pharniacie, xxiii. 480. xiii. 62. § Ibid. Hi. 155. KTIIION. \cin. 191 mtyra- e solu- ;r tasto . heated otwith- •m with nt from [id t\»cm ric ao'id )hol and need by d. )ric acid ty dense I a little lisagrec- L'his sub- resolved the pre- indebted IS farther |)duccd by them by ; but his ttle atten- lus, in his liich seem lec' iieni IThc iii-st absolute IS acid is led. But I 480. if the temperature be kept low, and the process l)e conducted slowly, all the sulphuric acid is absorixMl by tli*> alcohol, and we obtain an oily-looking licpiid, without the disenwa. inont of any jraseous body whatever. If we employ too little alctih ,1, cryhtala of anhydrous sulphuric acid are deposited, which niav be itroserved for a long time under the lie tinu!, a sohdtle salt of barytes, very easily decomposed, and which can only be evaporated in vacuo over sulphuric acid. Tliiw salt is not an althioiuite of barytes ; for this last salt is soluble in alcohol, crystallizes, ; nd J^ives, at a high teniperature, sulphurous acid and sweet oil of w'me. But the new salt is not soluble in alcohol, can- not be m.' K, :.. ri J t,tallize, furnishes no sweet oil of wine when its temjc ia„uri.) is elevated, but only sulphuric acid in great quantity, while ■• pC'Mllar empyreumatic odour is perceptible. This new salt was analyzed by M. Magnus, who obtained. 2 atoms sulphuric acid . . 10 1 atom barytes . . . !)'5 I atom ether . . . 4'()25 24-125 The only difterence observed between the constituents of this salt and those of althionate of barytes is that the althionate contains two atoms water, while this salt contains none. Liebig examined this salt,* and considers it as a mixture 6f isethionate of barytes and altliionate of barytes. The presence of this last he considers as the reason why Magnus obtained in his analysis 1 per cent, more barytes, and 1 per cent, less carbon, than theory indicated. Liebig found that the solution, when saturated with carbonate of barytes, may be evaporated by heat without de- composition. When concentrated and mixed with alcohol, a white matter fell, which, being washed with alcohol and dried, became a white powder. It is remarkable that it may be exposed to a red heat in a platinum crucible and decomposed, without the peculiar frothing which characterizes the althionate of barytes. It loses no weight when heated to 212'' At 302° it gives out a smell like that of sulphuric acid and oil ot wine. Liebig found that the althionic acid might b' driven off by boiling the licjuid before it was saturated V. • ' ' arytes, and that the purified acid when saturated with barytes and the solution concentrated, deposited needle-form crystals. If we now mix the liquid with alcohol, the ethionate of barytes is deposited. When this salt is washed in alcohol and dissolved in 40 times its weight of boiling water, it is deposited quite pure when the liquid cools. The crystals arc «ibliqut prisms, very like chlorate of pot- * Ann. | ^'1^ ! ash. They undergo no change in the air, though exposed to a heat of 392°. At a higher temperature, water, sulphurous acid and sulphur are driven off, and there remains a mixture of sulphite and sulphate of barytes. When treated with sulphuric acid and ignited, it leaves from 66*8 to 67 per cent, of sulphate of barytes. When mixed with saltpetre and carbonate of potash, and ignited, and then treated with nitric acid and chloride of barium, it gives twice as much sulphate of barytes as by the former treatment. From these facts Liebig concludes (and the opinion is very probable) that this salt consists of 1 atom hyposulphuric acid . . 9 1 atom C* H* O . . . 4-5 1 atom barytes .... 9*5 23 And he considers ethionic acid as a compound of S^ 0^+C^ IV 0+H O. There is reason, from the experiments of Liebig, to consider the isetliionic acid of Magnus as identical with the ethionic. SECTION II. SULPHONAPHTHALIC ACID. This acid was considered as a compound of two atoms of sul- phuric acid and one atom napti aline, and has been described as such in the Chemistry of Inorganic Bodies (vol ii. p. 177). But the analysis of Faraday, on which this conclusion was founded, did not quite agree with it. The subject has since been investigated by Berzelius.* The sulphonaphthalate of barytes (formed by dissolving carbonate of barytes in sulphuric acid digested on naphthaline), he found a mixture of two salts diflScult to separate exactly. But he succeeded in the following way : — Evaporate the solution of these salts till a pellicle begins to appear on the surface. Then mix the liquid with twice its bulk of alcohol of 0*833. In a few minutes oni of the salts bej^ins to precipitate in a white powder. After an interval of between 12 and 16 hours the white powder ceases to precipitate. But a good deal of labour is necessary to separate the two salts completely from each other. The salt held in solution is the true sulphonaphthalate of barytes. It crystallizes in brilliant plates, which, when dried, have a silvery aspect. It gives from 41*7 to 41-9 per cent, of sulphate of barytes. This is nearly 2 per cent, more than it would have yielded had it consisted of 2 atoms of sulphuric acid united to 1 atom of barytes. Berzelius considers it as a compound of 1 atom hyposulphuric acid . S^ O® 2 atoms naphthaline . . 2 (C" H^) 1 atom barytes . . . Ba O But it has been recently analyzed by M. Regnault, who found its constituents to be, when dried at 356°, * Jour, de Pharrn. iv. 842. HYPOSULPHONAPIITHALIC ACID. 103 to a land ! and ilted, iVhen I then ice as these it this ler the , of sul- •ibed as But the did not rated by irbonate 'ound a cceeded ts till a uid with the salts jetween it a good ly from barytes. a silvery barytes. d had it barytes. If ound its Rarytes 27-35 Sulphur 11-7(5 Carbon 43-15 Hydrogen 2-63 Oxygen 15-11 100* Leadini>' to the formula 1 atom barytes ^ 9*5 or pel • cent. 27-64 2 atoms sulphur =: 4 — 11-64 20 atoms cai'boi = 15 — 43-64 7 atoms hydrogen ^ 0-875 2-54 5 atoms oxygen = 5 — 14-54 34-375 100 This is obviously equivalent to 1 atom barytes 1 atom hyposulphuric acid S^ O* 1 atom of . . . C20 H^ g2 03 C^o H^ C^^ W is 2 atoms of naphthaline minus 1 atom uf hydrogen. This hydrogen had combined with an atom of oxygen of the sulphuric acid, and thus had converted 2 atoms of that acid into 1 atom of hyposulphuric acid. The crystallized acid contains an atom of water. M. Regnault has examined some of the sulphonaphthalates with much care. SECTION III. OF HYPOSULPHONAPHTHALIC ACID. This is the acid contained in the salt precipitated in the state of white powder from the true sulphonaphthalatc of barytes. It dissolves slowly in water, and less abundantly than the preceding salt. It is very little soluble even in dilute alcohol. It gives 50 per cent, of sulphate of barytes. When heated in a glass tube it gives at the instant of decomposition a little naphthaline sublimed, and an acid gas which has not a sulphureous odour, but affects the palate with the peculiar sensation given by sulphurous acid. This salt was found composed of Sulphate of barytes Sulphuric acid Carbon Hydrogen 99-886 These numbers give the following as the constitution of the salt : * Ann. lie Chini. ct de Phys, Ixv. 90. o 50-930 or 1 atom 17-507 or I atom 29-523 or 1 1^ atoms 1-926 or 4-38 atoms !fil a>^ ll 'B ■ukM '. i! 194 COMPOUND ACIDS. 2 atoms sulj)liuric acid 1 atom barytcs 1 1 atoms carbon 4^ atoms hydrogen 10 !)-5 8-25 0-5625 28-3125 It is obvious that the base, with which the sulpliuric acid was com- posed, was composed of C" H'**. SECTION IV OF HENZOSULPHUniC ACID. This acid was discovered and described by M. Mitscherlich in 1834.* His process for obtaining it was the following : — Common fuming sulphuric acid is put into a phial to which benzine is added by small quantities at a time as long as the acid continues to dissolve it ; taking care to agitate the phial well after each addition. Heat is evolved during the combination, which would injure the process. The phial therefore must be kept cool by means of cold water. The acid is now dissolved in water, which occasions the separation of a small quantity of a substance to which Mitscher- lich has given the name of snlphohenzide. It is easily separated by the filter. The acid is now to be saturated with carbonate of barytes, and as the benzosulphate of barytes is obtained only in crystalline crusts, it is best to filter the solution and to precipitate the barytes by adding the exact quantity of sulphate of copper requisite for that purpose. When the liquid is evaporated to the requisite consistency, large crystals of benzosulphate of copper are obtained. The benzosulphates of zinc, iron, silver, potash, soda and ammonia, also crystallize quite well. The benzosulphate of copper is dissolved in water, and the cop- per precipitated by a current of sulphuretted hydrogen gas. When the liquid, thus freed from copper, is concentrated to the consistence of a syrup it leaves a crystalline residue, which undergoes decomposi- tion if we elevate the temperature too high. The benzosulphates bear a pretty high temperature without undergoing decomposition. Mitscherlich raised benzosulphate of copper to 428°, and its solu- tion in water did not precipitate barytes water. At 338° it loses all its water. Mitscherlich, before analyzing this salt, kept it for a quarter of an hour in the temperature of 356°, to ensure the com- plete disengagement of the water. M. Mitscherlich afterwards found that when benzoic acid is added to concentrated sulphuric acid it dissolves with facility ; but, wlien the solution is diluted with water, the benzoic acid is again separated. When benzoic acid is added to anhydrous sulphuric acid, heat is evolved, and a combination takes place, the whole being con- verted into a viscid, translucent mass. When we dilute this mass with water, the excess of benzoic acid (if too much has l)(!en added) will separate, but a combination of the sulphuric acid and benzoic * Poggcndorrs Annalen, xxxi. 283, and xxxii. 227. Ann. dc Cliim. ct de I'lij s. Ixvi. 318. UENZOSULPHUUIC ACID. 195 IS com- vlich in » which the acid ell after ;h \vould y means ccasions litscher- rated hy onate of [ only in •ecipitate f copper ed to the ipper are soda and the cop- Vhcn the tence of composi- lulphates position. its solu- it loses it for a ;he com- lis added ; but, lis again Iric acid, ling con- iiis mass added) benzoic do Phjs. acid will remain, constituting benzosulphuric acid. When this acid is saturated with carbonate of barytes, the liquid filtered, and muriatic acid added to the liquid, the benzosulphate of barytes is deposited in crystals. To obtain the salt pure let it be dissolved in twenty times its weight of water at C8°. By evaporating this solution we procure the salt in a state of purity. It acts as an acid on vegetable blues. It undergoes no alteration in the air. When treated with smoking nitric acid and other oxy- dizing substances, the sulphuric acid is not disengaged. Heated to 392'' it loses 10-63 jier cent, of water. After this loss no more water can be driven off from it. Mitscherlich analyzed it, and obtained from 100 parts of the salt : Barytes . . 28-36 or 1 atom Sulphuric acid . 2 3<)'()8 or G atoms = O-O Oxvjjen or per cent. 50*0 4*2 -_ _ 5-8 — — 40-0 lOO-OO But ineconin is And half an atom nitrous acid If) 1 00-0 C" IP O* C)» A/j which make up the constituents of hyponitromeconie acid. Hence, this acid nmst be a compound of 1 atom meconin I atom nitrous acid It would he better to call the acid nitromeconic acid. It combines readily with the bases, and forms salts that have been but imperfectly examined. Potash, soda, and ammonia, dissolve it with exti'eme facility. The hyponitromeconate of potash is very soluble. TIio yellow colour of the acid is much deei)ened by com- bining it with bases — so much so, that it passes into red. When an acid is poured into any of these salts, the hyponitromeconie acid is precipitated unaltered. The salts of iron and copper are precipitated by it, the former reddish-yellow, the second li0 or 4 atoms = 8 — — 39"75 Carbon 22-5(i50 or atoms = 4-5 — _ 22-30 Hydrogen 3*1153 or 5 atoms = 0*025 — — 3*11 Oxygen 10*4570 or 2 atoms = 2*0 — — 9*94 100-0000 20*125 100 But one of the atoms of the oxygen was in combination with the * • • • potassium, constituting it potash. Hence the constituents of xanthic acid must be S' C*^ H"' (). Now, this may be resolved into * Poggfiidorrs Amialen, xxxii. 307. I i ru^ If" 204 COMI'Ot'ND ACIDS. 2 atoms liistilpliurot of carbon S* V/^ I atom ttulphuric ctlior C* II'* O It is obvious from this, tliat xantbic acid is a coinpoimd of two atoms bisulphurct of carbon, and one atom of otbcr, and tbat its atomic weigbt is 14'12r). To verify tbis atomic weigbt, M. Zeisc* »inuly/cd several neutral xantbates, and found tbein »'omposed jis foHows t — Xnnthatc of potash was sometimes prepared by saturating an al- cobolic solution of potasb witli bisnlpburet of carbon, ami sometimes by adding bydrate of notasb to an alcobolic solution of bisidpburot of carbon. It was tlried in vacuo, over sulpburic acid. By ana- lysis, tins salt was foend composed of Xantbic acid . . "tO'.M or 14-25 Potasb 2i)-(i.'J or () Hy tbis analysis tbe atomic weigbt of xantbic acid is 14**25, ditl'er- ii)g from tbe tbeoretic nund)er by only ()'12.'>. Xnnt/inte of soda wiM olitained by saturating an alcobolic solu- tion of soda witb bisulpburet of carbon. Wlien evaporated in vacuo, it sometimes gave a colourless salt in rbond)oidal crystals, and some- times a yellow-coloured nuiss, composed of needle-form crystals in tufts. Tbe first were dissolved in alcobol, and tben completely dried. Tbe last were dissolved in water, and tbe solution evapo- rated till tbe needle-form crystals were deposited in sucb quantity as to give tbo wbole tbe consistence of pap, and tben subjected to ])ressure between folds of blotting-pajjcr, wbicb imbibed all tbo colouring matter ; and tbe colourless crystals were fully dried in vacuo over sulpburic acid. Xantbate of soda was composed of Xantbic acid . . 1235 or 14-2.3 Soda ... 347 or 4 1582 Xanthate of barytes was made in tbe following manner : — Anby- drous barytes in fine ])owder was j)ut into a solution of bisulpburet of carbon in absolute alcobol. Tbe mixture was left carefully covered for some hours. It was filtered wbile it contained unconi- bined bisulpiiuret of carbon. It was then put utvler tbe receiver of an air-pump, and a vacuum being made as quickly as possible, was dried over sulphuric acid. Xantbate of barytes was composed of Xantbic acid . . <)1-18 or 14-05 Barvtes . . . (i2-17 or 9'5 1.034-.35 23-55 Xanthate of lead was obtained, by mixing togetlujr solutions of nitrate of lead and xantbate of potasb. At fi'-st ibere was an excess of tbe former salt, but afterwards xantbate of j)otasb was added till it constituted an excess. By tbis method we obtain pure xantbate of * rnp:i.'cn(lorf''!> Aiiiialcii, xxxv. tS7. XANTIIIC ACID. 205 of two that its neutrul iX iiu III- riU'timos il[)lmrot liy uua- >, differ- lie solu- in vacuo, n(l some- crystals nipletely n evapo- quantity jected to I all the 1 dried in -Auliy- ilplniret arefuUy uncoin- receiver )Ossil)le, tions of Ixcess of ]d till it lliate of lead ill fine powder, whieh may bo collected on the llUor, vvarfaol, and drieil. Xanthate of lead was romposed of Xanthic arid . . 4o3H or l4'lo Oxido of h-ad . . 4487 or 14 The xnnthatc. of r.opjx : , examined hy M. Zeise, was a compound of xanthic acid and siihoxide of copper. It cannot he formed di- rectly, hy mixinix tof,'i'ther anueous solutions of salts. The jiortion suhjectcd to analysis was obtained hy nuxinr> The atomic weij?ht of xanthic acid, deduced from the composition of these salts, with the exception of the last, comes so near 14*125, as to leave no doubt that the constitution of this acid, as determined hy M. Zeise, is correct. He made numerous additional experi- ir.eotg, to determine the composition of xanthate of potash and xan- thate of lead. He obtained Potassium .... 24*287 Sulphur .... 39*880 Carbon .... 22*583 Hydrogen . . . . 3*189 Oxygen .... 10*001 100*000 Numbers which serve to confirm his previous analysis. M. Couerbe has analyzed the xanthate of potash and the xanthate of lead.* The results obtained for. the first of these salts agree very closely with those of M. Zeise. liut the constitution of xan- thate of lead found by him, differs totally from that found by M. Zeise. According to him it is composed of Sulphur .... 29*720 Carbon .... 16*940 Hydrogen .... 1*843 Oxide of lead . . . 51*497 100*000 This would make xanthic acid S* C° H*. It would be a compound of S* C^, or two atoms of bisulphurct of carbon, and C* H*, or an • Ann. tie Cliim. et ilc I'hys. Ixi. 239. I! a ;» m ,»'■ I m I i-'f 2()f; CORirOUND Acins. atom of tctarto-carboliydrogcn. It would differ from the xanthic acid of Zoise by the absence of an atom of water. But MM. Lie- bi"- and Pelouze repeated the analyses both of xanthate of lead and xantliate of silver, and found their composition to be exactly as stated by M. Zeise.* Hence M. Couerbe's notion, that when xan^ thic acid unites with metallic oxides, it always loses an atom of water, is not correct. SECTION XIII. — OF rORMOBENZOILIC ACID. This acid was first formed by M. Winckler. But for the knowledge of its properties and composition we are indebted to M. Liebig.f It may be obtained by mixing the water distilled off bitter al- monds with a quantity of muriatic acid, and then evaporating it. It remains in crystalline masses, mixed with sal ammoniac, from which it is easily freed by ether, which dissolves the new acid, but does not touch the sal anmioniac. It is white, very soluble in water, has a strong acid taste, neu- tralizes bases, and forms with oxides of silver and copper, crystal- line salts, little soluble in water. It decomposes the acetates, ben- zoates, and formates. When heated, it melts in its water of crys- tallization, and at a higher temperature it is decomposed, leaving a considerable residue of charcoal, and giving out an odour like that of peach-blossoms. The crystallized acid, according to Liebig's analysis, is com- posed of 16 atoms carbon . . . =12 8 atoms hydrogen . . . =1 6 atoms oxygen . . . =6 19 In the salts of silver and copper it is anhydrous, and, composed of 16 atoms carbon . . =12 7 atoms hydrogen . . = 0*875 5 atoms oxygen . . = .5 17-875 It is obvious, from this formula, that it is a compound of 1 atom formic acid . . C^ H O' 1 atom hydret of benzoil . C'^ H« O^ Oil of bitter almonds is a mixture of hydrocyanic acid and hydret of benzoil. The hydrocyanic acid with water, is decomposed into formic acid and ammonia. For 1 atom of hydrocyanic acid C H Az 3 3toms water . . H' 0' I Ann. dc Cliim. ct de Phvs. Ixiii. 135. C^ H^ Az O' + Ibid. Ixii. 135. nYDROCAKUOSUI.PHURU" ACID. 207 1 atom formic acid 1 atom ammunia C^ II O'^ IF Az neu- C2 H« Az 0» When a solution of the new acid is heated with binoxidc of man- ganese, a strong effervescence takes place, carbonic acid is formed, and there distils over liydret of benzoil perfectly pure. This constitutes the first well-authenticated example of an acid, formed by the combination of two organic bodies possessing the characters of acids, and capable of being formed at pleasure. Many others will, no doubt, hereafter present themselves. Doubt- less, several of the acids described in this work are in this predica- ment. SECTION XIV. — OF HYDROCARBOSULPHUUIC ACID. Already described in the Chemistry of Inorganic Bodies (vol. ii. p. 175). M Ii i>.'ii CFIAPTER VII. OF CYANOGEN AND ITS COMPOUNDS. hydret Ised into A FULL account has been given of cyanogen and its coTT.pounds, in the Chemistry of Inorganic Bodies (vol. ii. pp. 208 — 255). Our object here will be, to state the additions which have been made to our knowledge of this important class of compounds, since the pub- lication of that work. For these additions, we are chiefly indelited to the genius and industry of Liebig and Wiihler. It will be recollected that cyanogen* is a compound of 2 atoms carbon and 1 atom azote, or C^ Az, that it combines with the sup- porters of combustion, and forms 1 Cyanic acid C^ Az +0 2 Chloride of cyanogen li (C Az) -|- ChPi 3 Bromide of cyanogen Ig (C^ Az) + Br'* 4 Iodide of cyanogen 1| (C^ Az) -{• Pi The first of these compounds has been described in the Chemistry of Inorganic Bodies (vol. ii. p. 225), under the name of cyanous acid, because, at that time, it was believed by chemists, that there existed another compound of cyanogen and oxygen containing two atoms of oxygen, and therefore entitled to the name oi cyanic acid. Liebig and Wobler overturned this opinion, by showing that the cyanic acid of SeruUas contained hydrogen. It will be described * Some very interesting experiments have been lately made by M. Pelouze and Mr Richardson, on tlie spontancons decomposition of cyanogen in water. Be- sides azulmic acid, there was formed hydrocyanic acid and carbonic acid, am- tnonia, urea, and oxalate of ammonia. :,.i! mm M Hi:* Hi ' I • i If 3 1 I ! { it: 208 OF CYANOr.EN AND ITS COMPOUNDS. in this Chapter under tlie name cyanuric acid, by wliich it was dis- tinguished by Liebig and Wiihler. Cyanogen was known also to combine with liydrogen, sulphur, and selenium, and to fonu 1 Hydrocyanic acid . C^ Az 2 Disulphuret of cyanogen 2 (C^ Az) 3 Sulphuret of cyanogen C'^ Az 4 Bisulphuret of cyanogen C'^ Az 5 Seleniet of cyanogen C^ Az + 11 + s + s + S2* + Se? These compounds having been described in detail in the Chemistry of Inorganized Bodies, the reader is referred to that work for these and some other analagous compounds of cyanogen, which it is need- less to particularize here. But the following, having been unknown, or erroneously or imperfectly estimated, when that work was pub- lished, demand a place in the present volume : — SECTION I. -OF CYANUniC ACID. This acid, together with its analysis by Serullas, the discoverer of it, has been described in the Chemistry of Inorganic Bodies (vol. ii. p. 227), under the name of cyanic acid. VVohler and Liebigf found that when pure urea was heated strongly in a retort, ammonia was given off abundantly, and a yellow matter remained in the retort, which was a mixture of cyanuric acid with some ammonia. When this matter, which is white or yellowish- white, is dissolved in hot sulphuric acid, and nitric acid dropped into the solution till all effervescence was at an end, if we mix the cold solution with water the cyanuric acid is precipitated quite pure in a white crystalline powder. It may be obtained in large crystals by evaporating the saturated solution at 160° to about one half, and then allowing it to cool slowly. 100 parts of these crystals, when dried at 212°, fall to powder, and lose 21 '56 per cent, of water. Now it will appear immediately that the atomic weight of this acid is 8. Hence it follows that the crystals are composed of 1 atom cyanuric acid . . 8 2 atoms water . . . . 2*25 10-25 Liebig and Wohler obtained cyanurate of silver by mixing nitrate of silver and cyanurate of ammonia. It fell in white flocks, which did not become black when dried in the open air. It was anhydrous, and composed of Cyanuric acid . . 35*55 or 8 Oxide of silver . . C4*()5 or 14*5 100 * JoForilicil atul aiiiilyzod by Liebig. Sec PciggiMiilorre Ainiuleii, xviii. 355. t Ibid. XX, .'J7;j. PAS (lis- ulpbiir, hemistry or these is necd- nknown, ras pub- iscoverer c Bodies s heated . a yellow mric acid ,'ellowish- )pped into i. the cold pure in a ystals by half, and powder, mediately that the Ig nitrate IS, which [hydrous, iviii. 355. CYANIC ACID. 209 When cyanuric acid is dissolved in potash ley till the liquid re- fuses to take up any more, and the solution evapor.ited, wo always obtain an acid salt. But if we mix the solution with alcohol, the neutral cyanurate of potash precipitates in fine crystalline needles. If we redissolve these needles in water, and evaporate, we a^ain obtain an acid salt, and the solution becomes alkaline. The bisalt is but little soluble in water, and forms cubes, having considerable brilliancy. When heated the salt melts, cyanic acid is disengaged, a white insoluble matter sublimes, and cyanate of potash remains behind. It was analyzed, and found a couiponnd of Cyanuric acid . 15-84 or 7-92 >< 2 Potash . . 6 Obviously 2 atoms cyanuric acid, and I atom potash. The cyanuric acid, in an anhydrous state, being analyzed by Liebig and Wohler, was found composed of Carbon 27*921 or 3 atoms = 2-25 Hydrogen 2-397 or 1| atom = 0-1875 {\ atom = 2-625 3 atoms = 3-000 Azote. Oxygen 32-.575 or 37-10: or or per cent. 27*907 - — 2-:^ 27 - — 32-.;58 - — 37-208 100-000 8-0625 100 These atomic numbers may be resolved into li (C Az) + 0'* + H'l O'*; that is to say, an atom and a half of cyanic acid, and an atom and a half of water. SECTION II. OF CYANIC ACID. It was stated in the last section that cyanuric acid is resolvable into an atom of cyanic acid, C^ Az O, and an atom of water H O. Liebig and V\'()hler have shown that when anhydrous cyanuric acid is subjected to dry distillation, a volatile, transparent liquid passes over, which is a compound of 1 atom cyanic acid, and 1 atom water.* The receiver must be surrounded by a mixture of snow and salt. The anhydrous cyanuric acid is to be gradually heated to incipient ignition. The liquid cyanic acid obtained is a colourless liquid. Its smell is strong and disagreeable, somewhat similar to that of concentrated acetic acid. It is very volatile, and when mixed with gaseous bodies, long preserves the gaseous state. It acts strongly on the eyes, oc- casioning a copious flow of tears. It reddens litmus, and is the most corrosive of all known acids. The smallest drop of it applied to any part of the skin produces instantly a blister, accompanied by severe pain. It is not combustible. This liquid acid has very little permanence, so little indeed that it has been impossible to determine its characters witli minute pre- cision. When taken out of the freezing mixture, and exposed to the common temperature of the air, it becomes milky, thickens like gruel, and becomes hot. Frequent and successive explosions take * Pi'Srgendorf's Atmalen, xx. 383. ■:"(« ■K \ i IP 210 CYANOGEN AND ITS COMPOUNDS. r> i f 'III place in it, so tbat one is afraid of the destruction of the vessel con- taining it. In a short time it is converted into a white, dry, taste- less powder. This change does not occupy a longer time than five minutes. When a portion of the liquid is put into a well-closed vessel, and surrounded with ice, so as to preserve the temperature at 32°, the same alteration takes place, only it is not accompanied by explosions. When we attempt to separate cyanic acid from its salts, by means of an acid containing water, it is immediately decomposed into car- bonic acid and ammonia. When the vapour of liquid cyanic acid is passed into water, it is absorbed as rapidly as ammoniacal gas. In a short time the whole liquid becomes filled with small bubbles of carbonic acid gas. By degrees it becomes warm, and a strong effer- vescence takes place. The liquid, which was at first acid, becomes alkaline when evaporated, and smells strongly of ammonia. On cooling it concretes into a white opaque matter, consisting of a mixture of urea, and the white substance into which the acid spon- taneously changes. It appears, from the experiments of Wohler and Liebig, that the liquid acid is speedily converted into carbonate of ammonia. The addition of a new portion of acid drives off the carbonic acid, and forms cyanate of ammonia. Thi^, cyanate, by uniting with an atom of water, is speedily converted into urea ; while a third portion of the acid is converted into the white substance already noticed. SECTION III. -OF INSOLUBLE CVANURIC ACID. Liebig and Wohler have distinguished the insoluble white matter into which cyanic acid spontaneously changes by the name of insolu- ble cyanuric acid; because though its properties be very different, its elementary constitution is identical with that of cyanuric acid. It was discovered by Liebig in 1829.* It may be obtained also by triturating together crystals of oxalic acid and cyanate of potash. It is a white powder, without ttie least appearance of crystalliza- tion. It is insoluble in water, inui'iatic acid, and nitric acid, and is not altered by fuming nitric acid, or aqua regia. It dissolves readily in caustic potash, and, when the solution is evaporated, we obtain cyan urate of potash. Ammonia is disengaged during the evapora- tion, rendering it probable that some cyanate of potash was also present. When exposed to heat, the insoluble cyanuric acid behaves exactly as the crystallizable acid, being converted into liquid cyanic acid. When gently heated with sulphuric acid the white powder is de- composed, pure carbonic acid gas being disengaged. In the solution we find a little ammonia, and nothing else, provided the acid employed wa; pure. This white matter, being analyzed by Liebig and Wohler, was found to consist of the same o(mstituents as cyanuric acid, united in % * Pog^'cndorf's Aiinaleii, xv. iU3. CYANILIC ACID. 211 cl con- , taste- lan five [-closed erature npanied y means nto car- 3 acid is ras. In ibbles of ng effer- becomes lia. On ing of a cid spon- , that the ia. The acid, and 1 an atom portion of iced. itc matter of insolu- different, uric acid. ;d also by potash, rystalliza- id, and is readily in l^ve obtain evapora- was also |d behaves lid cyanic ier is de- le solution the acid [liler, wjis 1 united in the same ratios. They found further that the white matter, when dried at the temperatin-e of 212°, lost 3 1*08 per cent, of water. If we consider this water as constituting 3 atoms, we have the composi- tion: White matter . . 68-92 or 8-065 Water . . . 31-08 or 3-79 100-00 The number 3-79 comes as near 3-375, or 3 atoms water, as could be expected in such an experiment. Hence there can be little doubt that the white insoluble matter is isomeric with cyanuric acid. SECTION IV OF CYANILIC ACID. This acid was discovered by M. Liebig in the year 1833.* When sulphocyanodide of potassium is decomposed in the dry way by chlorine, we obtain a yellow powder. If we carefully wash this yellow powder, mix it with chloride of potassium, and then boil it in nitric acid, it dissolves by little and little, and the solution, on cooling, deposits colourless and transparent crystals of ajanilic acid. The sulphocyanodide of potassium is decomposed by chlorine more easily if we mix it with twice its weight of common salt in powder. It ought not to be brought into a state of fusion, because, under these circumstances, the action is violent, and the decomposi- tion incomplete. The best way is to heat by a bath of solution of chloride of calcium and not to increase the heat till towards the end of the process. At the beginning of the process chloride of sulphur passes over, but when a red heat is applied, long needles of chloride of cyanogen are deposited in the beak of the retort. The crystals of cyanilic acid are washed with water to remove all nitric acid. They are then dissolved in hot water, and allowed to crystallize by slow cooling. The crystals are large plates, having a metallic or pearly lustre. They contain water of crystallization, which they lose completely and with facility when kept in a warm dry room. When the anhy- drous acid is submitted to distillation it yields the same products as cyanuric acid under the same circumstances; namely, hydrated cyanic acid, which changes quickly into the white substance, insolu- ble cyanuric acid, described in the last Section. No residual matter remains. The composition of cyanilic acid is precisely the same as that of cyanuric. The crystals, when perfectly dried, lose 21 per cent, of water, exactly the loss sustained by hydrated cyanuric acid. When burnt with oxide of copper, the gas which comes over is a mixture of 2 volumes carbonic acid and 1 volume of azotic gas. Liebig, in order to determine the atomic weight of this acid, analyzed the cyanilate of silver, formed by nnxing nitrate of silver with cyanilate of ammonia. By a first experiment it was composed of * Ann, de Chim. ot de Plivs. Ivi, 40. w w Ha 212 CYANOGEN AND ITS COMPOUNDS. i urn ^ I . t 494 or 16-31 439 or 14-5 Cyanilic acid Oxide of silver By a second, it was composed of Cyanilic acid . . 298-45 or 15-2G Oxide of silver . 283*55 or 14-5 The mean of these two analyses gives us 15*785 for the atomic weight of cyanilic acid.* If the atomic weight he 16, as is probable from these analyses, it will follow that cyanilic acid, though the ratios of the atomic consti- tuents be the same, yet contains twice as many atoms of each con- stituent as cyanuric acid. It must be 3 (C^ Az) H' O"^. This would make the atomic weight 16*125, which does not deviate much from that resulting from the first analysis of cyanilate of silver. SECTION v. — OF ALLANTOIN, OR ALLANTOIC ACID. This is the substance described in the Chemistry of Inorganic Bodies (vol. ii. p. 167), under the name of allantoic acid. MM. Liebig and Wiihler formed it artificially by mixing pure uric acid with water to the consistence of a thin pap, heating the mixture nearly to the boiling temperature, and then adding, by small quan- tities at a time, peroxide of lead in fine powder. An effervescence took place, carbonic acid gas was extricated, and the colour of the peroxide of lead was destroyed. When all action was at an end, the liquid was filtered. Oxalate of lead remained on the filter. The colourless liquid deposited, on cooling, crystals of allantoin. And when concentrated, crystals of urea were deposited. Thus by the action of peroxide of lead, uric acid was converted into carbonic acid, oxalic acid, allantoin and urea : and these were the only products.! Liebig and Wiihler ascertained the identity of the crystals thus deposited with the allantoic acid of Lassaigne by a comparative analysis of each. Allantoin forms colourless transparent rhombic crystals. They are hard and very brilliant. They were obtained about three lines long, and from a half to one line in thickness. It is tasteless, and does not act on litmus paper. At the temperature of 68°, one part of it requires for solution 160 parts of water. It is more soluble in boiling water, and is deposited in crystals as the solution cools. It had been already shown by C. G. GmelinJ not to bo capable of neutralizing bases, and therefore not entitled to the riame of acid : and his experiments were confirmed by those of Liebig and Wiihler. Oxide of silver constitutes, however, an exception. When a hot solution of allantoin is mixed with nitrate of silver, and ammonia dropt in as long as any precipitate falls, a white powder is obtained, which is a combination of allantoin and oxide of silver. This com- pound is decomposed by all dilute acids, allantoin being left behind unaltered. • M. Liebig says that his second analysis gives the atomic weight of the acitl 16'2C ; but unless there be a typographical error in the numbers given, the true atomic weight deduced from them is only 15"26. f PoggendorPs Aniialcii, xli. jG'2. J Gilbert's Aunalen, Ixiv. 351. ALLANTOIC ACID. 213 itomic ses, it jonsti- h con- This ; much er. organic MM. ric acid mixture 11 quan- ^escence r of the end, the r. The n. And IS by the nic acid, oducts.t als thu3 parative They ree lines ess, and one part oluble in (ols. It pable of of acid: Wbhler. len a hot ammonia ibtained, his cora- "t behind Df the acid In, the true 351. I At a high temperature, allantoln is decomposed by the caustic alkalies into ammonia and oxalic acid. This decomposition is most easily obtained by means of barytes. If we dissolve allantoin in boiling hot barytes water, ammonia is disengaged, and a white powder falls, which is oxalate of barytes. When allantoin is heated with concentrated sulphuric a;;id, carbonic acid and carbonic oxide gases are disengaged, and ammonia remains in combination with the acid. Allantoin was subjected to analysis in Liebig's laboratory, and found composed of Carbon 30-20 or 4 atoms = Hydrogen 4*04 or 3 atoms = Azote 35*27 or 2 atoir- = Oxygen 30*49 or 3 atoms = 3 or per cent. 30*38 0*375 — — 3*80 3*5 — — 35*44 3*0 — — 30*38 100*00 9*875 100*00 We might consider it as a compound of 2 atoms cyanogen (2 (C Az) ) and 3 atoms water (3 (H O) ). To convert it into oxalate of ammonia we must add to it 3 atoms water. For Allantoin . . C* Az^+H^ O^ 3 atoms water . . H^ O' C^ AzHH« 0« Now 2 atoms oxalate of ammonia are C* O" +Az'^ H*^. The allantoate of silver was analyzed in Liebig's laboratory, and found composed of Allantoin . . . 56*45 or 18*79 Oxide of silver . . 43*55 or 14*5 100 But the atomic weight of allantoin, as determined by the preceding analysis, being 9*875, two atoms will weigh 19*75 It is obvious from this that the compound consists of 2 atoms allantoin united to 1 atom of oxide of silver. The difference between 19*75 and 18*79 being 0*96, which approaches an atom of water, Liebig conceives that the 2 atoms of allantoin united with the atom of oxide of silver have lost an atom of water, so thpt their constitution has become C8 Az* H5 O^ The knowledge of the constitution of allantoin enables uf > ex- plain the reactions which take place when uric acid and peroxide of lead are made to act on each other. 1 atom uric acid is . C" Az* H* 0« 1 atom urea is . C^ Az^ H* O^ Remain . . C» Az^ O* To this add O* from peroxide of lead O^ * (: (■' C« Az» 0« 214 APPENDIX. These atoms are resolvable into 2 atoms oxalic acid . 2 atoms cyanogen To these 2 atoms of cyanogen, if we add a atoms water, we have of allantoin. Az* H' O^, or an atom SECTION VI. — OF URIC ACID. I have nothing to add to the account of this acid given in the Chemistry of Inorganic Bodies (vol. ii. p. 15G), except to correct the analysis. It has been subjected to a careful analysis by M. Liebig, who considers its atomic weight to be 2 1 , the salts formerly called binurates being, in his opinion, simple urates. He considers its composition to be C" H^ Az' O". We have seen in the last Sec- tion how, by the action of peroxide of lead, it may be resolved into oxalic acid, allantoin, and urea. .'ii ir , I ii; APPENDIX. ON THE METHOD OF DETECTING THE VEGETABLE ACIDS, AND Ol' DISTINGUISHING THBiM FROM EACH OTHER. Many of these acids have been so imperfectly examined, that it is not in our power to point out simple characters by which they may be detected. But it mav be useful to mention the method of ascer- taining those acids with which we are well acquainted, and which are freciuently used as cliemical reagents. 1. Acetic acid. This acid, when j)urc, is easily known by its smell, which is quite peculiar. It forms soluble salts with all the bases. Nitrate of mercury throws it down from several of its saline solutions ; but not in all cases. It docs not occasion any precipi- tate in a solution of albumen or gelatine, though it does in a solu- tion of chondrin. 2. Oxalic acid. If we saturate this acid with ammonia, so as to form a neutral salt, the solution of this salt, though very dilute, throws down a white precipitate when dropt into a dilute solution of chloride of calcium. Neither tartaric, citric, nor malic acids, occasion an immediate precipitate when thus treated. When oxalic acid is mixed with binoxide of manganese in line powder, or with bichromate of potash, and sulphuric acid or muriatic acid poured upon the mixture, an effervescence takes place, and carbonic acid is given off. When concentrated sulphuric acid is poured on crystals of oxalic acid, and heat applied, the acid is converted into carbonic acid and carbonic oxide gases. 3. Tartaric, rocemic, citric, and malic acids may be distinguished from each other in the following way : — Dissolve the acid to be tried in the smallest quantity of water. MKTIIOI) or DKTECTINc; VECiKTAHLE ACIDS. 215 t atom in the rect the 'Ay Licbi { called Icrs its st Scc- ed into AND OF that it is hey may )f ascer- id which a by its 1 all the ts saline precipi- a solu- |so as to dilute, I solution tie acids, In oxalic or with poured acid is [crystals carbonic jiruished water. To the solution add iiu excess of lime water, so that the mixture may restore the blue colour t)f reddened litums paper. (1.) If the acid bo citric or malic, no precipitate falls ; but if it be tartaric or racemic, a white i)recipitate appears. (2.) If the acid be tarlaricy the addition of a little sal ammoniac will completely redissolve the precipital (3.) But if it be racemic, it will not be redissolved by this addi- tion. (4.) If into a neutral solution of tartrate of ])otash or soda, chlo- ride of platinum be added, a black powder separates, which is me- tallic i)latinum. Ikandes dissolved I grain of tartaric acid in 1 000 grains of water, saturated it with potash, and added five drops of chloride of platinum. On heating the mixture, or rather boiling it, it became almost as black as ink, and a black powder gradually fell to the bottom.* (5.) U tartaric acid be dropt into a solution of sulphate of lime, no precipitate falls. (().) But when racemic acid is dropt into a solution of sulphate of lime, a precipitate gradually falls. (7.) The solution of citric acid gives, with lime water, no preci})i- tate while cold ; but if the mixture be raised to the boiling tempera- ture, a copious white precipitate falls. (8.) If the citric aeir: solution be very dilute, the precipitate pro- duced by boiling disappears again when the liquid cools. (9.) Malic acid is not precipitated by lime water, whether cold or hot.t 4. Lactic acid does not crystallize, but may be reduced to the consistence of a syrup. It has no smell, and is soluble in water, alcohol, and ether. Coagulates milk and albumen. Precipitates acetate of magnesia in the state of lactate, and the liquid acquires the smell of acetic acid. Precipitates ?.lso acetate of zinc. Doet' not throw down lime, strontian, or barytes water. 5. Formic acid. If this acid, or Jbrmate of soda, be added to a solution of any salt of gold, platinum, or silver, an effervescence takes place, carbonic acid gas is given off, and the gold, platinum, or silver is deposited in the metallic state. When formate of soda is put into a solution of c* rrosive sublimate, calomel is precipitated. When formic acid is dro;jt into a solution of nitrate of lead, formate of lead is deposited in needles. 6. Pyrotartaric acid. It crystallizes with ease, and has no smell. Melts at 212". Does not render lime, strontian, or barytes water turbid. Does not precipitate salts of mercury, lime, barytes, nor sulphates of zinc, manganese, or peroxide of iron. Pyrotartrate of potash is a deliquescent salt. This acid does not form a bisalt with potash. 7. Pyrocitric acid crystallizes with difficulty. Its other charac- * Annalen der Phanti. ix. 302. t Sec H. Rose, I'oggendorf's Annalen, xxxi. 219, If •:« 111 ■!;' ^m ! ■'ft I ■'■(. $, H ';.atic needles or scales, having a fine white colour, and a satiny bistre. The characters of succinic and benzoic acids rescuiblo each other 80 closely, that it is very difficult to distinguish these tw) acids from each other by reagents. M. Macaire-Princep, however, has pointed out two reagents, which produce ditterent ett'ects upon them. 1. A neuti 1 solution of benzoato of ammonia, gives, with the salts of copper, iipale ash-coloured powder ; while succinate of ammonia gives a copious, curdy, fine green precipitate. 2. With the salts of cobalt, benzoate of aunnonia gives a copious, ^ocAy precipitate, of a white colour, with a sliyht shade of red ; while succinate of ansmo- nia scarcely renders the liciuid muddy, and a whole day elapses be- fore a scarcely perceptible red precipitate falls.* 14. Caffeic acid. A white po*vder, insoluble in alcohol, but soluble in water. Lime water colours it yellow, but occasions no precipitate, nor is it precipitated by protonitrate of mercury, or acetate, or subacetate of lead. Does not become green with chloride of iron, nor strike a green with ammoniated copper. Barytes water throws down a yellow precipitate. Albumen a flocky precipitate. When strongly heated it gives out a smell simi- lar to that of roasted coffee. 15. Amygdalie acid. Crystallizes in plates or scales. Has a slight smell of bitter almonds. Taste acid, styptic, and peculiar. When heated it melts into a yellow oily-looking fluid, which concretes on cooling into a translucent gummy-looking mass. A higher temper- ature drives it off in white smoke, which has the smell of hawthorn blossom. 1(). Hippuric acid. Forms largo transparent brittle crystals. When heated, melts and becomes black, while benzoic acid sublimes, and a distinct smell of bitter almonds is perceived. 17. Cinnamonic acid. Appears in old oil of cinnamon, in brown prisms. Soluble in boiling water, and deposited in white plates as the solution cools. Alcohol is a good solvent of it ; melts at 248°, boils at 559°. When sl'wly heated, sublimes in brilliant plates, simi- lar to benzoic acid. Its vapour excites coughing. Its salts are very like the benzoates. 18. Tannin or tannic acid. A white powder. Taste very as- tringent. Without smell. Very soluble in water. Precipitated white by muriatic, nitric, phosphoric, and arsenic acids ; but not by oxalic, tartaric, lactic, acetic, citric, succinic, or selenious acid. ' It precipitates glue, and strikes a black with the salts of iron. Absorbed rapidly by alumina, and forms with it a very insoluble compound. 19. Gallic acid. Does not precipitate solutions of glue or isin- * Jour, dc Pharmacic, xv. 529. ii !■! .fi I 'Am I ; TmwM I* M i! 21 N AI'l'KNDIX. glnsH. roriiiH wliilo crvstjilji. Striko.-t a iloop-hliio colour with m\U oF iron. With liiiii?, Ixirytcs, and strontiuii watcM", tiirowrf down white j)roci|)itiit('s. With acetate of lead, a white precipitate. Tannin and ijaUic (uid umy he* distinj^fiiished from each other hy the followinj,'' characters : — In dilute solutions of <;old, liallic acid strikes a jfrei'uish-hhie colour, apj)oariii<»' hrowu hy reflected li^jfht, nnd reduces the <,n)ld to the metallic state; but tannin strikes a purple. In solution of titanium, gallic ucid strikes a tint of brown, scarcely percei)til)le, while tannin throws down ordngt- red Hocks. '1 annin precipitates tartar emetic wlUte ; irallic acid renders it mndtti/ only after a certain time (fallie acid <,nvet; a brown colour to the pure alkalies ; to the alkaline carhonates a brownis/i-i/c/foir, which passes into green. Tannin is precipitated hy the pure alkalies and hy their carhonates, and tl'j Tupud assumes a brown colour, whii'h does not pass into i^reen. The salts of nu)r- phinn, strychnina, ipiinina, and cinchoninu, are nut precipitated hy gallic acid, hut they an; hy tannin.* 20. ryrogallic acid. C'rystals white plates. Taste bitter and cooling. With barytes and strontian water no precipitates. Changes persulphate of iron into proto3ulj)hate, and strikes a fine reddish- brown colour without oc^casioning any precipitate. 21. Metagallic acid. A black, tasteless, and very brilliant matter, insoluble in water. Dissolved easily by potash, soda, or ammonia, and precipitated by an acid in black Hocks. 22. Ellagic acid. A liglit-bufi', tasteless powder, insoluble in boiling water ; unites and neutralizes potash, soda, or .ammonia, but the salts are insoluble, but become soluble when a little alkali is previously dissolved in the water. When agitated in lime water, sepa- rates the lime. Does not melt when heated. When distilled a green- ish-yellow vapour passes over, having the properties of ellagic acid. 23. Kinic acid. Very like tartaric acid. Soluble in 2^ times its weijjlit of cold water. Soluble also in alcohol. Its salts all soluble in water. 24. Meconic acid. Crystals transparent scales, soluble in 4 times their weight of water. When the solution is boiled, it becomes in succession yellow, red, and deep-brown. Strikes a red with the ])er- salts of iron. When nitrate of silver is dropt into a solution of me- conic acid, and a little more nitric acid is added than is sufficient to dissolve the meconate of silver, if we heat the liiiuid, the silver is converted into cyanodide of silver. If too much nitric acid be added, much oxalate of silver is formed, but no cyanodide. 25. Metnmtconic acid. Strikes a red with the persalts of iron. Re- quires 16 times its weight of water to dissolve it, while meconic acid is much more soluble. 2(). Pyromecunic acid. Melts at 248'^, and while fluid resembles an oil. May be volatilized in a gentle heat. 27. Camphoric acid. In feathery crystals. Taste acid and bitter. * Ptaft', Jour, de Pharinacio, \\. 434. \ \ I METHOD OF DETECTING VEOF.TAIU.E ACIDS. 21!) I down thcr by iU" iic'ul trlkort a tint t)l' orange- llic acul trivoti a )natfs a Uated l)y smncs a ( of nior- tatcd by ittm- and Cliannes reddiah- brilliant soda, or soluble in lamnionia, alkali is ter, sopa- a green- iiH. Suhvric nritf. A white solid, soluble in water. '2ob°. May be distilliMl over. 2!>. Ca/iincic acid. Crystals white needles. No stnc^ll. Solidde hi 30 H'6 Az 0^ 12 Brucina . C32 H'8 Az 0^ 13 Veratrina (.34 H32 Az ()' 14 Emetiua (;35 J.p5 Az ()" Ij Solaniiia C" H''^' Az» O^H are all irogen, ,ve clis- cd from found ; )r ine — pium by ggetable now be- termina- the re- a of this lat were name of oda, and jmists to y British lierefore, ite in a : lames for s. The ;e in in. meconin iin of the Iccording MENISPEUMINA. 16 Narcotina C" H2" Az Q19. 17 Morphina C"' H>« Az 0« 18 Atropina C^'' H>« Az O^ 19 Conicina C'2 H'* Az O 20 Parillina C» W 0' 21 Meconin CIO H5 0* 223 It will 'jf seen, that each of these alkalies contains an atom of azote, with the exception of solanina, which contains only half an atom, and parillina, which contains none. The two bodies termi- nating in in are not alkalies. SECTION I. — OF MENISPERMINA. The fruit of the menispermum cocculus (cocctdus suherosus of De- candolle), a black berry about the size of a pea, which comes from the East Indies, was first examined by M. Boullay in 1811, who ex- tracted from it a peculiar poisonous substance, to which he gave the name of picrotoxin,* an account of which has been given in a preceding Chapter of this volume. It was examined in 1825 by AI. Casaseca, who concluded from his experiments that it was destitute of rlkaline properties, and incapable of uniting with acids.f In 1833, the subject was resumed by Pelletier and Couerbe, who examined picrotoxin with great care, and showed that it possessed rather the properP^* of an acid than a base.J But these gentlemen detected two alk^,^ *n the cocculus indicus, to which they have given the names ■ !spermina axid paramenispermina. These alkalies were obtained from the covering of the seeds of cocculus indicus in the following manner: — The matter was reduc- ed to a coarse powder, and digested in boiling alcohol as long as any thing soluble was taken up. The tinctures were filtered, and the alcohol drawn off by distillation, till the liquid was reduced to the consistence of an extract. This extract being digested in hot water, a brown-coloured liquid was obtained, which when mixed with ammonia, let fall a brown-colourea precipitate. The colour was in a good measure removed by treating it with water acidulated with acetic acid. This dilute acid dissolves the precipitate with the exception of a black matter, and a little phosphate of lime. The matter being again precipitated by ammonia, assumes the form of a greyish-yellow resin, which when left undisturbed at the bottom of the vessel soon assumed the form of a powder. Being dried, dissolved in alcohol, and left to spontaneous evaporation, it fur- nished three distinct substances. 1 . A sul)stance having a resinous appearance, and alkaline properties. This substance Pelletier and Couerbe denominate yellow alkaline matter, and consider it as similar to a substance found in the mother water of nux vomica, cinchona, opium, &c., after the extraction of strychnina, quinina, morphina, &c. * Aim, (le Chim. Ixxx. '209. f Ann. de Cliira. et de Phys. xxx. 307. i Ibid. liv. 178. !» I ij I. I? \h I 1 I m 224 ALKALIES ANALYZED. I|» ih 2. The second substance is crystallized in fine prismatic needles. This is menispermina. 3. The third substance has the aspect of a bufF-coloured mucilage. This is parametiispermina. These three substances may be separated from each other in the following; manner : — Cold hydrous alcohol dissolves the yellow alkaline resin. Ether dissolves the menispermina, while absolute alcohol dissolves the paramenispermina, and deposits it in crystals. Menispermina thus obtained 's white and opaque, and has very much the external appearance of cyanodide of mercury. The crystals are four- "ed prisms, terminated by four-sided pyramids. It is tasteless, ar a seems to have no marked action on the animal economy. At least, 6 grains taken into the stomach produced no sensible effect. It melts when heated to 249°. When heated in a glass tube it is decomposed, and leaves a bulky charcoal. But if it be heated in a watch glass, so as to allow free access to the air, it leaves very little charcoal behind it. It is insoluble in water. Alcohol and ether dissolve it cold, and still better when hot. When the solutions are concentrated, the menispermina is deposited in crystals. Dilute acids dissolve it, and at the same time are neutralized. From these solutions the alkalies precipitate menispermina unaltered. Concentrated sulphuric acid while cold has little action on it ; but when assisted by heat, dissolves it unaltered, as it is again precipi- tated by the addition of water and ammonia. Concentrated nitric acid has little action on menispermina while cold, but when assisted by heat it converts it into oxalic acid, and a yellow-coloured resin- ous-looking matter. Sulphate of menispermina crystallizes in prismatic needles. It melts at 329", and while li'^aid resembles wax. When the heat is increased, the menispermina becomes red, and is decomposed, while sulphuretted hydrogen gas is given off. The constituents of this salt, determined by the analysis of Pelletier and Couerbe, are Sulphuric acid ... 5 Menispermina . . . SC'Sl Water 10-90 Pelletier and Couerbe consider this sulphate as a subsalt, composed of 4 atoms menispermina united to 1 atom sulphuric acid. If this opinion be well founded, the atomic weight of menispermina will be 14-25. They subjected it to an ultimate analysis, and found its consti- tuents as follows : — Carbon 71-80 or 18 atoms = 13-5 or per cent. 72 Hydrogen 8-00 or 12 atoms = 1-5 _ — 8 Amtc 9-57 or I atom = ?-75 — — 9-33 Oxygen 10-53 or 2 atoms = 'i-00 — — 10-«37 99-90 18-75 100-00 This analysis makes the atomic weight 18-75, wliicii does not cor- f CINCHONINA. 225 eedles. jct of a e three Uowinji e resin. issolve3 las very '. The ^ramids. B animal luced no s tube it leated in ives very cold, and •ated, the utralized. maltered. ,n it ; but n precipi- Lted nitric n assisted red resin- idles. It Ihe heat is ;ed, while Its of this are composed If this la will be [ts consti- •33 •07 •00 not cor- respond very well with the number 14'25, derived from the analysis of sulphate of menispermina. Perhaps, therefore, it would be bet- ter (especially as very few tetrasalts are known) to consider the sul- phate of menispermina, analyzed by Pelletier and Couerbe, as a disul- phate, which would make the atomic weight of menispermina 28*4, and to consider the constituents to be 27 atoms carbon = 90'25 or per cent. 72 18 atoms hydrogen = 2*25 — — 8 n atom azote = 2-625 — — 9-33 3' atoms oxygen = 3-000 — — 10-67 as 28-125 100 before, but the number of atoms IS Here tha ratios remain increased by one-half. Poramenispermina is solid at the ordinary temperature of the atmo»i here. Its crystals are oblique four-sided prisms, generally arrange; d in stars. It is not easily decomposed on account of its volatility. When heated in a glass tube it sublimes unaltered. If it be heated in a watch-glass, it begins to be volatilized in a white smoke before it has been completely melted. If the glass '^o with- drawn from the flame we see this smoke fall down again like snow, and the globule of melted paramenispermina becomes enveloped in a brilliant crystalline crust. The fusing point may be fixed at 482°, and the point of volatilization is nearly the same. It is not sensibly soluble in water, and ether dissolves it in very minute quantity. Its true solvent is absolute alcohol, and the solu- tion is promoted by heat. The mineral acids have very little action on paramenispermina at the temperature of 57**. When heat is applied they decompose it. Dilute acids dissolve it ; but without being neutralized or altering their form. Of course paramenispermina does not possess alkalkine properties, nor does it form salts. Yet its constituents, according to the analysis of Pelletier and Couerbe, are exactly the same as those of menispermina. SECTION II. OF CINCHONINA. This alkali was detected by Pelletier and Caventou, in . ^20, in the grey Peruvian bark, which is considered as the bark of the cinchona nitida, or the cinchona condaminep* and is not much esteemed for its medical properties. But there is reason to suspect that the cin- chona lancifolia of Loxa, the most celebrated of all the varieties of cinchona, contains the same principle. Pelletier and Caventou extracted it from this bark by the follow- process : — 2 kilogrammes (4? lbs. avoirdupois) of grey bark in powder were digested in 6 kilogrammes (131 lb.) of alcohol. Tliis treatment was repeated four times. The alcoholic tinctures were all united, * Ann. de Chim. et de Phys. xv. 289. Q 926 ALKALIES ANALYZED. i:i ■m i) f u ■'7- and the alcohol was distilled oft" after the addition of 2 litres (122 cubic inches) of water. The residual liquid was filtered, and it left on the filter a reddish matter apparently resinous, which was washed with water containing a little potash till the liquid passed without colour. The matter remaining on the filter, after being well washed with distilled water is greenish-white, very fusible, soluble in alcohol, and capable of crystallizing. It was cinchonina, not quite freed from foreign matter. To purify it, they dissolved it in very dilute muriatic acid. The weak acid dissolved the cinchonina, but left undissolved the greater part of the mattei th which it was mixed. The solution, which had a golden-yello olonr, was digested with magnesia, assisted by a gentle heat. Ijs magnesia, which was employed in excess, decomposed the muriate of cinchonina and formed a precipitate con- sisting of the cinchonina mixed with the excess of magnesia. It was collected on a filter, and washed with cold water till that liquid passed colourless. The precipitate was now dried on the water- bath, and treated thrice successively with boiling alcohol, which dis- solved the cinchonina. The solutions, when evaporated, deposited crystals of a dirty-white colour. But, by a second solution and crystallization, they wer'^ obtained quite white and brilliant. It crystallizes i,i delicate prismatic needles, or in white hairy translucent tufts. It requires 2500 times its weight of boiling water to dissolve it, and, on cooling, the liquid in general becomes opaline; showing that cinchonina is more soluble in boiling than in cold water. It has a peculiar bitter taste, which is not much perceived at first on account of its very little solubility. When rendered soluble by being united with acids, its taste is very bitter, styptic, and per- manent, similar to a strong decoction of cinchona bark, only less astringent. It is not altered by exposure to the air. When heated in a some- what large-sized tube the dry cinchonina does not melt, but furnishes a crystalline sublimate ; whether this sublimate be the unaltered cinchonina has not been determined. It is very soluble in alcohol, especially when assisted by heat. A saturated alcoholic solution at a boiling temperature crystallizes on cooling. The alcoholic solution is very bitter. It is soluble in ether, but less so than in alcohol, especially while cold. It is slightly soluble in fixed oils, and still more soluble in volatile oils, at least in oil of turpentine. Pelletier formed an iodide of cinchonina by the following process : Cinchonina was triturated with half its weight of iodine, and then digested in alcohol of 0"837. When the solution is left to spontan- eous evaporation the iodide is deposited in safron-coloured plates. Towards the end of the evaporation some hydriodate of cinchonina is deposited. The colour of the iodide is a deep-yellow. Its taste is slightly bitter. When heated to 77° it becomes soft, and melts at 116°. It CINCHONINA. 227 -es (122 , and it liich was d passed :er being ■ fusible, ichonina, ;id. The iG greater on, which ssisted by n excess, )itate con- nesia. It that liquid the water- which dis- deposited ilution and ant. jvhite hairy )iling water les opaline ; nan in cold iived at first soluble by , and per- ils, only less in a oome- lut furnishes unaltered jd by heat, ktallizes on jcially while soluble in \cr process : and then to spontan- Ired plates. Icinchonina is slightly 176°. It is insoluble in cold water, and very little soluble in boiling water. It is soluble in alcohol and ether. When acted on alternately by acids and alkalies it is decomposed. According to the analysis of Pelletier, it is composed of 1 atom iodine . . . 15*75 2 atoms cinchonina . . 38*5 p. and D.+ Liebig.t Henry and Pliisou.^ 76-97 76-36 73-88 6-22 7-37 8-876 9-02 8-87 9-3522 7-97 7-40 2-8918 100-18 100 100-0000 54-25* Cinchonina does not combine with combustible bodies, nor with those oxides that are destitute of acid properties. It was analyzed by Pelletier and Dumas, and ' y Liebig, and by Henry and Plisson. The following table shows the results : — Carbon Hyuiogen Azote Oxygen Liebig found that 630 parts of dry cinchonina absorbed 143 parts of muriatic acid. Hence the muriate of cinchonina is composed of Muriatic acid . . . 4-625 Cinchonina .... 20-36 This makes the atomic weight of cinchonin? ' 36. But the ultimate analysis of Liebig, which was made with very great care, leads to the conclusion that the atomic weight is 19'25, and the constituents as follows : — 20 atoms carbon =15 or per cent. 77-93 12 atoms hydrogen = 1"5 — — 7*79 i atom azote = 1-75 — — 9*09 1 atom oxygen = 1-00 — — 5-19 19-25 100-00 Liebig's analysis would agree much better with the supposition that the integrant particle of cinchonina contains 1 J atom oxygen. It would then stand thus, 20 atoms carl ,n =15 or per cent. 76 12 atoms hydrogen = 1-5 — — "J'S 1 atom azote = 1-75 — — 8-8 1| atom oxygen = 1*50 — — 7'6 19-75 100-0 These numbers agree almost exactly with the result of Liebig's analysis. The salts of cinchonina have a bitter taste They are precipi- tated by oxalates, tartrates and gallates, and by the infusion of nut- * Ann. de Chira. et de Pliys. Ixiii. 181. t Il»id. xxiv. 176. X Poggendorfs Annalen, xxi. 24. § Jour, de Phariuacie, xvii. 4.'>3. i ■ ;i l! |i; i I ill m 228 ALKALIES ANALYZED. galls. Cinchonina combines in two proportions with acids, forming' neutral salts and disalts, or salts composed of 2 atoms base united to 1 atom acid. 1 . Muriate of cinchonina. The composition of the neutral mu- riate formed by exposing dry cinchonina to the action of muriatic acid gas has been already given. When we dissolve cinchonina in muriatic acid we always obtain a (limuriate, which crystallizes in needles. It is very soluble in water. It dissolves also in alcohol but scarcely in ether. Its composition, according to the analysis of Pelletier and Caventou, Is Muriatic acid . . . 4* 625 Cinchonina . . . 39*42 This is obviously 2 atoms of cinchonina to 1 atom of muriatic acid. 2. Hydriodate of cinchonina. This salt is but little soluble in water; but if we saturate boiling water with it we may obtain the salt in crystals by allowing the solution to cool. The crystals are trans- parent needles with a pearly lustre. With 'corrosive sublimate and with cyanodide of mercury it forms curdy precipitates, which, accord- ing to Caillot, are double salts. It is more soluble in hot water, and crystallizes during the cooling of the solution. At first it seems tasteless ; but it leaves a bitter and metallic impression.* 3. Sulphate of cinchonina. When sulphuric acid is satursited with cinchonina, we obtain, as Baup has shown, a disulphate, which crys- tallizes in short oblique prisms terminated by bihedral summits. It dissolves in G parts of alcohol of the specific gravity 0*85, and in 1 1 parts of absolute alcohol. It is soluble in 54 times its weight of cold water. Its constituents are 1 atom sulphuric acid . . 5 2 atoms cinchonina . . . 40*5 4 atoms water . . . 4*5 50 When dried in a temperature of 248°, it loses all its water of crys- tallization. If we add sulphuric acid to the solution of disulphate of cinchonina and evaporate till a pellicle forms on the surface, we obtain, after allowing the liquid to remain sometime at rest in a cool place, crys- tals of neutral sidphate of cinchonina. This salt is colourless, does not undergo any alteration from ex- posure to the air, except becoming slightly opaque in a dry atmo- sphere. The crystals are octahedrons, consisting of two four-sided pyramids with rhomboidal bases. They effloresce when slightly heated. It is soluble in about hnlf its weight of water at the tem- perature of 55°, in rather less than its weight of alcohol of the sp. gravity 0*85, and in its own weight of absolute alcohol at the same temperature. Its constituents are Pelletier, Ann. de Chim. ct de Phvs. Ixiii. 183. CINCHONINA. 229 3, fomiinff ; united to cutral mu- f muriatic ys obtain a e in water, imposition, uriatic acid. c soluble in tain the salt Is are trans- il)limate and nch, accord- n hot water, first it seems I.* iturated with , which crys- summits. ity 0-85, and les its weight I atom sulphuric acid I atom cinchonina H atoms water 20'25 irater of crys- )i cinchonina obtain, after ll place, crys- Ition from ex- a dry atmo- vo four-sided jvhen slightly [v at the tem- lol of the sp. ll at the same 34-25 4. Nitrate of cinchonina. This salt must be prepared by satu- rating very dilute nitric acid with cinchonina. When its solution is pretty concentrated, whether it be hot or cold, a portion of nitrate of cinchonina separates in globules having an oily appearance. If these globules be covered with water they are converted in two or three days into groups of crystals. This curious character distin- guishes cinchonina and quinina (which possesses it also) from all the other vegetable alkaloids. 5. Carbonate of cinchonina. Cinchonina absorbs carbonic acid from the atmosphere. The carbonate may be obtained by precipi- tating a soluble salt of cinchonina by an alkaline carbonate, 6. Phosphate of cinchonina. T' "s salt is very soluble, and only forms the rudiments of crystals, or assumes the form of transparent plates. 7. Arseniate of cinchonina. This salt is very soluble in water and crystallizes with difficulty. 8. Chlorate of cinchonina. This salt maybe obtained by dissolv- ing cinchonina in chloric acid. It crystallizes in white tufts. When heated it melts, and if the heat be increased it is decomposed with an explosion. It is less fusible and more easily decomposed than chlorate of quinina. According to SeruUas this salt is a dichlorate. 9. lodate of cinchonina , Obtained like the last. It crystallizes in very fine needles in tufts. According to SeruUas it is a diodate of cinchonina. It is composed of 1 atom iodic acid . . . 20*75 2 atoms cinchonina . . 38*5 5()-25* 10. Acetatt of cinchonina. Acetic acid dissolves cinchonina ; but the liquid remains acid, whatever quantity of cinchonina we employ. When concentrated it deposits small translucent scales. When these scales are washed they are no longer acid, and are little soluble in water. When we evaporate to dryness we obtain a gummy mass, which water decomposes into binacetate, which dissolves, and diacetate, which remains undissolved. 11. Tartrate of cinchonina. This salt is similar to the oxalate, but is more soluble in water. 12. Oxalate of cinchonina. It precipitates in the form of a white powder, little soluble in water when an oxalate is mixed with a salt of cinchonina. By adding an excess of acid it becomes soluble, forming a binoxalate. 13. Gallate of cinchonina. Gallic acid throws down a precipitate i '>■ B ■'- w- i'i 'J'ii; %' 1 . • -A' . 'ii; * Pellcticr, Ann. dc Cliim. ct do Plus. Ixiii. 18.'j. li't I' R ' I ! ! 1 1 ' 1 1 1 i l':if Al i :> 230 ALKALIES ANALYZED. from a solution of a cinchonina salt, which is scarcely soluble in cold water. But it dissolvos when the liquid is heated. On cooling, the liquid becomes milky, but, after some hours, it becomes again trans- parent, and tlie gallate of cinchonina ia deposited in &uiall granular translucent crystals. 14. Tannate of cinchonina is composed, according to M. O. Henry, of Tannin . . . 72-84 or 54-30 Cinchonina . . 27-16 or 20-25 100-00* It is therefore a tertannate. 15. Kinate of cinchonina. When the solution of this salt is con- centrated to the state of a syrup and set aside for a few days it de- posits silky needle-foi-m crystals, which are very soluble in water. It is composed of Kinic acid . . . . 11*94 Cinchonina .... 19-75 It is therefore a dikinate. 31-()9t SECTION III. — OF QUININA. Some steps toward the discov ery of this principle, certainly one of the most important of all the alkalies, was made by Vauquelin,^ and by Gomes, in 1811 ;§ but it was Pelletier and Caventou who, ill 1820, pointed out its alkaline character, and showed how it may be obtained in a separate state. || Since that period sulphate of quinina has come into general use as a medicine, and has almost superseded the administration of bark. Quinina may be extracted from the yelloio bark, usually considered as the bark of the cinchona cardifolin, by the following process : — Let the yellow bark be coarsely pulverized, and boilcv^ in eight times its weight of water, containing live per cent, of sulphuric acid. Let this boiling be repeated, with an additional dose of acidulated water. Filter, and squeeze out the liquid portion from the undis- solved bark. Mix the liquid thus obtained with unslacked lime, amounting to a fourth of the weight of the yellow bark employed. Agitate well, and .as soon as tlie liquid begins to exhibit alkaline cliaracters, let it be passed through a filter. The lime remaining on the filter is to be w^ashed with a little cold water, exposed to pressure, and then dried. It is then to be boiled three times suc- cessively, in different portions of alcohol, of the specific gravity 0-83(). Mix the filtered alcoholic solutions with a little water, and distil off the spirit. The water remaining contains, mixed with it, * Jour, de Pharmacie, xxi. 221. f Henry and Plisson, Jour, de Pharmacie, xv. 406. + Ann. de China, lix. IIS. § Edinr. Med. and Surg'. Journal, 1811, p. 420. II Ann. de Chim. et de Phys. xv. 345. iJUlNINA. 231 »le in cold oling, the ;aiiJ trans- 1 oranular ;o M. O. lalt is con- days it de- 5 in water. ;rtainly one V^auquelin,$ entou who, how it may sulphate of has almost e extracted ic cinchona 3v1 in eight khutic acid. acidulated Ithe undis- jicked lime, employed. l)it alkaline remaining [exposed to ] times suc- Ific gravity Iwater, and led with it, Lim. lix. 113. the quinina, but not free from colouring matter. Lot it be dissolved in an acid, mixed with ivory black, and digested. When the filtered solution is now mixed with an alkali, the quinina is ^-recipitated in a state of purity. As sulphate of quinina is prepared on a largo scale for the use of medical men, it is more convenient to obtain quinina from that salt than to prepare it from the yellow bark. Nothing more is neces- sary than to dissolve the sulphate in water, and to mix the solution with a dilute solution of ammonia. The quinina falls in white flocks. It generally becomes a little coloured during the process of drying. Quinina crystaUizes with difficulty, and was long thought inca- pable of assuming a regular form. Pelletier first showed that when alcohol of 0'815 is saturated with it, and the solution set aside in a cool place, the quinina, by spontaneous evaporation, is deposited in silky tufts, consisting of minute needles. If we dissolve it in hot alcohol, and add a small quantity of ammonia to the liquid, and then set it aside to allow the liquid to cool, crystals of quinina are de- posited in fine needles. The crystallized quinina is in the state of a hydrjite. When it is exposed to heat it softens first, and then falls down in the state of a white powder. When heated to the temperature of 302", or a few degrees higher, it melts, and loses the whole of its water. When suddenly cooled, while in fusion, it becomes yellow, translucent, and brittle, like rosin. When slowly cooled it assumes a fibrous texture, and becomes opaque. When rubbed it becomes negatively electric. When quuiina, freed from water, is put into that liquid, it gra- dually swells, and absorbs again all the water which it had lost. Its taste is intensely bitter, similar to that of yellow bark itself. The taste is much stronger than that of cinchonina. It is soluble in 200 times its weight of boiling water. It is abun- dantly soluble in alcohol, and is usually deposited from it in a soft viscid mass, which becomes indurated in the air, and assumes the aspect of a resin. It is more soluble in ether than cinchonina is. Iodide of quinina may be formed in the same way as iodide of cinchonina, and the two iodides resemble each other so closely, that it is difficult to distinguish them. This iodide, according to the analysis of Pelletier, is composed of 1 atom iodine . . . 15" 75 2 atoms quinina . . . 40*5 56-25* We have four analyses of quinina, one by Pelletier and Caventou, one by Pelletier and Dumas,f one by Liebig,t and one by Henry and Plisson.§ * Ann. de Cliini. et de Phys. Ixiii. 184. t Pojrgendorfs Annalen, xxi. 25. + Ibid. xxiv. 1C9. § Jour, de Pharinacic, xvii. -l.^S. ■^"' M m !l 1 I'li 11 232 ALKALIEH ANALYZED. P.*C. p. & OuniM. Mobig. Henry ft Pllnon, 75 (i-25 8-75 10 75-02 (]-(;g ' 8-45 10-43 74-40 7-()l 811 9-88 74-552 8-4;i22 8-2y4(i 8-7212 100 100-5() 100-00 100-0000 Carlioii Hyilrogen Azote Oxygen To (lefermine the atomic weight of ([uinina, Leibig analyzed the sulphutf, ami found it composed of Quinina . . 85-83 or 42-9 15 Sulphuric acid . 10-00 or 5 Water . . . 4-17 or 2-085 100-00* This salt being a disulphate, it follows, from the above analysis, that the atom of quinina weighs 21-4575. The atomic constituents which would correspond best with Lie- big's analysis, are the very same as we have given for the constitu- ents of cinchonina ; namely, 20 atoms carbon = 15 or per cent. 74*08 12 atoms hydrogen = 1-5 — — 7-40 1 atom azote = 1-75 — — 8-04 2 atoms oxygen = 2-00 — — 9*88 20-25 100-88 But the atomic weight derived from the analysis of disulphate of quinina would indicate 21-25 at least. I am disposed (considering the difficulty of an exact analysis of sulphate of quinina) to adopt 20*25 for the atomic weight or quinina, and to conclude that cin- chonina agrees with it exactly in composition, but contains only one atom and a half of oxygen. This would reduce its atomic weight to 19*75. The salts of quinina arc distinguished by a strong bitter taste, similar to that of yellow bark, and those that are in crystals have a pearly lustre. Most of them are soluble in water, and several of them soluble in alcohol and in other. These solutions are preci- pitated by oxalic, tartaric, and gallic acids, and also by the infusion of nutgalls. 1. Muriote of quinina. This salt crystallizes in needles, dis- tinguished by a pearly lustre. It is but little soluble in water. It would ajjpear, from the experiment-, of Liebig, compared with those of Pellet ier and Caventou, that there are two distinct apecies of this salt. According to Liebig, 100 parts of quinina absorb 24*1 parts of muriatic acid. But there was an excess of the acid, which had lodged itself in the pores of the (juinina. Allowing for this excess, the salt is obviously a compound of * PoggeiidoifV Aiinulcn, xxi. 'JC. QUININA. 1 atom nmriatic acid 1 atom (|uiiiiiia • • 4'(i2r> 20-25 233 1 I 1 24-87') The muriate of (juinina fonnod hy I'ollcticr atid (.'avontoii con- taiiifd only 7 ])i!r cent, of the niuriutic acid. Hence it is a com- pound of Muriatic acid . . . 4-()25 Quinina . . . . (!1*44 Now, 'Af^ = 20-48. So tlmt the salt of rolletier and Caven- o ton contained 3 atoms ciuinina, united to one atom muriatic acid. 2. Ili/driot/ale o/ f/uitiiua. This salt is formed alonjjf with iodate, when a mixture of (juinina and iodine is dis^ested in h.ot water, .^oth salts precipitate, when the liiiuid cools, in the form of a white pow- der. 3. Sulphate of qiiininn. The powerfully febrifufre propcrtio; of this salt has introduced it into jienerul use as a medicine in every part of the civilized world. On this account it has become an im- portant article of umnufacture, especially in France, where the cheapness of the; alcohol, compared with its jjrice in this country, enables the manufacturers to produce it at a much lower rate than could be done in this country. The animal produce in Paris, where it is chiefly made, exceeds 120,000 ounces per annum. The pro- cess usually followed is that of M. Henri, junior, with some sli^^ht modifications. It is as follows : — The yellow bark is reduced to powder, and boiled with 8 or 10 times its weight of water, acidulated with 12 per cent, of sulphuric, or 25 per cent, of muriatic acid. The boiling is continued for at least an hour, and the liquid is then strained through a cloth. The residual bark is boiled three or four times successively with new portions of acidulous water, till the liquids cease to acquire any taste. When these decoctions (which are all mixed together) ai'v i-^d, they are mixed with milk of lime, by small portions at a time, i;tking care to agitate without intermission, to promote the action of that base upon the acidulous liciuor. Lime must be added, slightly in excess, which is determined by ascertaining when the liquid acts like an alkali on vegetable colours. This excess forms, with the colour- ing matters of the bark, an insoluble lake. Accordingly, when enough of lime has been added, it will bo found that the liquid has lost its "cd colour, and become deep grey. The M»ewill occasion a considerable deposit. When it has sepa- rated from the liquid portion it is poured upon a cloth, and after the liquid part has run otf, the residual matter is subjected to a gra- duated pressure. The liquids must be set aside, because they gra- new dually dep if 1 '■'.; ;: i i : ! i j ' *!i . a, riie precipitated matter, thus freed from water, is allowed to dry, and then digested in alcohol, of the specitic gravity 0-847, in i ;=it*t 234 ALKALIES ANALYZED. % mm \ liilijf ty I order to dissolve the quinina. The digestion must be repeated, with fresh portions of alcohol, over the water-bath, till all the quinina is dissolved. The alcoholic liquids, containing the quinina, are now subjected to distillation, and about three-fourths of the alcohol employed is recovered. To the residual liquid sulphuric acid is added till it reddens litmus paper. The liquid is evaporated to the requisite quantity, and then set aside. The sulphate of quinina is gradually deposited in crystals. The great expense of this process is the quantity of alcohol con- sumed. M. Pelletier, some years ago, took out a patent for a new process, in which oil of turpentine is substituted for alcohol. The dry matter, from the action of lime on the acidulous decoctions of the bark, is digested in oil of turpentine, which dissolves the quinina. When the oil, containing the quinina, is agitated with water acidu- lated with sulphuric acid, the quinina unites with the acid, and the salt is held in solution in the water. The oil of turpentine swims on the surface, and may be decanted off. The sulphate is obtained in the usual way from this liquid by concentration. When this patent process is followed, it is said that the produce from the bark is about g'^th less than by Henri's process. This more than counterbalances the saving of alcohol, in consequence of which, Pelletier's process is seldom employed. Good yellow bark yields about ^^rpth part of its weight of sulphate of quinina, or from 34 pounds of tlie bark, one pound of sulphate of quinina may be ex- tracted by Henri's process. There are two sulphates of quinina : the disulphate, and the neu- tral sulphates the former is the one commonly employed in medi- cine. Disulphate of quinina effloresces vhen exposed to the air. It is soluble in 740 times its weight of water at the temperature of 55°, and in thirty times its weight of boiling water. It dissolves in eighty times its weight of alcohol of the specific gravity 0*85, at the ordinary temperature of the atmosphere. It crystallizes in tufts, composed of fine needles, which are slightly flexible, and have a pearly lustre. When heated it readily melts, and assumes the ap- pearance of liquid wax. At a still higher temperature it assumes a fine red colour, and at last burns all away, without leaving any residue. From the analysis of this salt, by Liebig, stated in a preceding page, it is evident that it is a compound of 2 atoms quinina . . . 40*5 1 atom sulphuric acid . . 5 2 atoms water . . . 2*25 47-75" ♦ The analysis of this salt by Robiquet comes exceedingly near these theoretic numbers. See Ann. dc Chim. ct de Phys. xvii. 320. with ina is [ected yed is till it ^uisite dually )1 con- a new The ions of uinina. acidu- md the I swims htained produce This lence of ow bark or from ly be ex- the neu- in medi- It is of 55S eighty at the tufts, have a the ap- assumes ving any Dreceding QUININA. 235 m This, however, is the constitution of the salt after it has efflor- esced. The crystals consist of 2 atoms quinina . . . 40*5 1 atom sulphuric acid • . 5 8 atoms water ... 9 54-5 Neutral sulphate of quinina was first made and analyzed by Robi- quet.* It may be formed by adding a little sulphuric acid to the solution of the disulphate, and crystallizing the solution. The crys- tals are rectangular prisms, with rectangular or square bases. At the temperature of 55°, it dissolves in eleven times its weight of water ; while at 72°, it requires only eight times its weight of that liquid to dissolve it. At 212° it is soluble in its water of crystalli- zation. It is much more soluble in hot than in cold alcohol, what- ever the specific gravity of the alcohol may be. When crystallized in alcohol the crystals fall to powder on exposure to the air. It reddens vegetable blues, though its taste is not perceptibly acid, but bitter. Its constituents, from a comparison of the analyses of Ro- biquet and Baup, appear to be 1 atom quinina . . . 20*25 1 atom sulphuric acid . . 5 8 atoms water ... 9 sc theoretic 34-25 The high price of sulphate of quinina, and its great importance in medicine, have induced fraudulent dealers sometimes to adul- terate it by a mixture of foreign matter. Sulphate of lime in needles, boracic acid, margaric acid, and sugar, are the ingredients most commonly employed for that purpose. The presence of sul- phate of lime, or boracic acid, is easily ascertained by incinerating a portion of the suspected salt. The sulphate of lime or boracic acid will remain behind. Margaric acid may be separated by means of weak muriatic acid, which dissolves sulphate of quinina, but leaves the margaric acid. To detect sugar, we may dissolve a little of the suspected salt in water, and throw down the sulphuric acid by means of barytes water. The quinina will fall at the same time, and a current of carbonic acid gas will throw down any excess of barytes which may have been added, leaving nothing but the sugar, easily recognizable by its taste. 4. Nitrate of quinina. Quinina combines readily with nitric acid, and \^ihen the solution is concentrated, the salt separates under the form of an oleaginous liquid, which gradually assumes a crys- tallized form. The crystals are rectangular prisms with inclined bases. 5. Phosphate of quinina. This salt crystallizes readily in small white needles, having a pearly lustre. It is soluble in alcohol, and also in water. * Ann. dc Cliim. el de Phvs. xvii. 317. 1| !>!.:! :;! 236 ALKALIES ANALYZED. 6. Arseniate ofquinina. This salt resembles the phosphate very closely, excepting that its lustre is less pearly. As the arseniate of cinchoniiia does not crystallize, we can easily distinguish between these two alkaloids by combining them with arsenic acid. 7. Chlorate ofquinina. It is obtained by saturating dilute chloric acid with quinina, and concentrating the solution. Its crystals are very line needles, united in tufts. When heated, it melts into a colourless liquid, which, on cooling, solidifies ; into a transparent varnish. If we increase the heat, the salt suddenly explodes, and is decomposed. 8. lodate ofquinina. Obtained in the same way as the preced- ing salt. It crystallizes in silky needles. 9. Acetate ofquinina. This salt is easily distinguished from the acetate of cinchonina. The latter salt, with an excess of acid, does not crystallize ; whereas the acetate of quinina, with an excess of acid, crystallizes readily. When the liquid acetate is concentrated, it assumes, all at once, the form of a solid mass, composed of long needles, having a pearly or silky lustre. By a slow evaporation the flat needles group themselves into stars. This salt is so little soluble in cold water, that when it is coloured it may be rendered white, bv washing it in cold water. It is much more soluble in hot water. A saturated solution in boiling water becomes solid on cooling. 10. Tartrate of quinina. Similar to the oxalate, but more soluble in water. 11. Oxalate of quinina. This salt maybe obtained, by mixing a solution of oxalate of ammonia with any soluble salt of quinina. It precipitates in the state of a white powder. It is but little soluble in cold water, but boiling water dissolves it better. A saturated boiling hot solution assumes, on cooling, the form of a pearly mass, composed of needles. Tlie neutral oxalate is very soluble in alcohol, and by allowing a saturated boiling-hot alcoholic solution to cool, the salt is deposited in white needles. 12. Gallate ofquinina. This salt precipitates in the form of a white powder, when a gallate is mixed with a soluble salt of quinina. The gallate of quinina dissolves in boiling water. When the liquid cools it becomes milky, and an opaque powder is deposited. Gallate of quinina is soluble in aicohol, and in an excess of acid. 13. Bitaftnate of quinina. The infusion and tincture of gall nuts, throws' down quinina from its solutions. The precipitate is scarcely soluble in water, but dissolves in acetic acid. It is com- posed, according to O. Henry, of Tannin . . . 71-48 or 50-75 Quinina . . . 28-52 or 20*25 1 00-00" Jiiiii. (Ic Phiiriiiauic, xxi ii'JI. h \'\ \ hate very arseniate 1 between ite chloric ystals are elts into a ansparent lodes, and he preced- d from the ■ acid, does n excess of iicentrated, sed of long )oration the is so little be rendered iluble in hot les solid on more soluble rl, by mixing quunna. It little soluble A saturated pearly mass, )y allowing a is deposited Ihc form of a jit of quinina. lien the liquid ^ted, Gallatc id. . ,, cturc ot gall brecipitate is ^ It is com- AUICINA. 237 This is rather a tertannate than a bitannate ; for 3 atoms of tannin weigh 49*875. 14. Kinate of quinina. This salt is very soluble in water, and crystallizes most readily when the solution has an excess of acid. The crystals are needles, or mushroom-shaped tubercles. Taste bitter. Composed of Kinic acid .... 10-42 Quinina . • . . 20-25 It is, therefore, a dikinate.* 15. Hydroferrocyanate of quinina. Hydrocyanate of quinina has been found a more powerful febrifuge than sulphate, but being kept in a liquid state, it is liable to undergo decomposition. This in- duced M. Berto?;/!, apothecary to the hospital of Cremona, to pre- pare hydroferrocyanate of quinina.f The process was as fol- lows : — One part of sulphate of quinina is reduced to an impalpable powder, and mixed with 1 \ parts of common prussiate of potash, previously dissolved in six or seven times its weight of water. The two substances being well agitated together, are put into a phial and gradually heated, under repeated agitation, to the boiling point. A greenish-yellow matter precipitates to the bottom, having an oily consistency. Decant off the liquid, wash the deposit with cold water, and dissolve it in alcohol. Filter, and evaporate. The salt is deposited in confused crystals. It has a greenish-yellow colour, and a very bitter taste. It dissolves in cold alcohol, but much better in boiling alcohol, and is precipi- tated by water. It was found an excellent febrifuge, chiefly in those cases where sulphate of quinina failed to produce a cure. SECTION IV. — OF ARICINA. This alkali was accidentally discovered in 1829, by MM, Pelletier and Cariol, in the following manner : — A dispute took place be- tween two Bourdeaux merchants, respecting a quantity of bark from Arica, in Peru, which had been sent to Europe as the bark of cinchona. It resembled the yellow bark exactly in its appearance, but it was alleged that no quinina could be obtained from it. A quantity of it was sent to Pelletier, in order to subject it to a chemi- cal examination. He and M. Cariol, who, at that time, had the charge of his laboratory, subjected it to the process described in the last Section, for extracting quinina from yellow bark. But, instead of quinina or cinchonina, they obtained a salifiable base possessed of quite difterent properties. To this base they gave the name of aricina, from the place whence it came- The name of the tree which yields this bark (employed in South America to adulterate cinchoua bark) is not known. Pelletier and Cariol drew up an ac- count of this new alkaloid, which was read to the Academy of Medi- cine in Paris, and published in the Journal de Pharmacie.X * Henry and I'lisson, Jour, dc Pharmacie, xv. 405. f Jour, dc IMiaruuicic, xi.\'. 4j, X ^"'' ^^'' !•• ^'•'^- il ='l ^i m . .',1 238 ALKALIES ANALYZED, .' ;!' ft ,« I ':l ! ,'! Jl 1: ill Aricina is white, and crystallizablc. It has considerable re- semblance to cinchonina, but differs from that base in many of its properties. It is insoluble in water. Hence it seems at first to have no taste, but when kept for some time in the mouth, it leaves a sharp and hot impression. When dissolved in an acid, its taste becomes intensely bitter. When heated it melts, like quinina, at a temperature lower than that at which it undergoes decomposition ; but it cannot be volatil- ized like cinchonina. Like the other alkaloids, it saturates acids, and forms with them salts. The sulphate of aricina is not crystalHzable from its aqueous solution. When we dissolve the salt in boiling water, it assumes, on cooling, the form of a white tremulous jelly, which, when left exposed to the atmosphere, assumes the appearance of horn. This matter, when digested in boiling water, is again converted into a jelly. When dissolved in boiling alcohol it crystallizes in silky needles, having much of the aspect of sulphate of quinina. When we add to the gelatinous sulphate a few drops of sulphuric acid, a bisulphate is formed, which crystallizes in flat needles. When aricina is dissolved in concentrated nitric acid, it assumes a very deep-green colour. If the acid be weaker the green colour is lighter, and when it is very dilute it dissolves the aricina without communicating any colour whatever. In this last case, a simple nitrate of aricina is formed ; but when the aricina assumes a green colour its nature is altered. This alkaloid was subjected to an ultimate analysis by Pelletier,* who obtained the following result : — Carbon 71 or 20 atoms = 15 or per cent. Hydrogen 7 or 12 atoms = ['5 — — Azote 8 or 1 atom = 1*75 — — Oxygen 14 or 3 atoms = 3*00 — — 70-59 7-06 8-24 14-11 100 21-25 100-00 If the atomic weight of aricina be 21-25, and its constituents as now stated, it is obvious that a very simple relation exists between cin- chonina and aricina. The atoms of carbon, hydrogen, and azote, are the same in all : the only difference in their constitution lies in the proportion of oxygen, which is 1 ^ atom in cinchonina, 2 atoms in quinina, and 3 atoms in aricina. This will become more evi- dent, if we represent the atomic constitution of these bodies by symbols : Cinchonina . (C^o H'^ Az) + O'l Quinina . . (C^" H'^ Az) + O^ Aricina . . (C»" H'^ Az) -h (F I • Ann. de Cliim. et de Phys. li. 13G. SAMCIN. 239 letier,* I as now len cin- azote, lies in atoms •ve evi- lies by SECTION V. — OF SALICIN. Though this substance does not possess alkaline properties, I am induced to place it here, in consequence of the analogy which it bears to the alkalies from the different varieties of cinchona. It appears to have been discovered by M. Buchner in 1828.* It was detected in 1830, by M. Leroux, in the bark of the salix helix.] It may be obtained by the following process : — Boil the powdered bark with water till a strong decoction is obtained. Add to this decoction slacked lime till all the tannin is precipi- tated in the state of ditannate of lime. Then filter and concen- trate the liquid to the consistence of a syrup, or we may precipi- tate the tannin by the white of eggs. Add alcohol, which will precipitate the gum. If we now concentrate the liquid it deposits salicin, which may be washed in a little cold water. By mixing the brown-coloured mother water with the diacetate of lead, we may obtain from it another portion of salicin. Dissolve all the salicin thus obtained in boiling water, and digest the solution with ivory black. Filter the boiling solution, and allow it to cool. It depo- sits pure colourless crystals of salicin. Salicin thus obtained has the form of small white scales, which, under the microscope, appear to be rectangular tables with bevelled edges. Its taste is very bitter, and it has something of the aro- matic flavour of the willow bark. One hundred parts of water at the temperature of 67 , dissolve 5*6 parts of it. Hot water is a much better solvent, and boiling water dissolves it in any proportion whatever. It is soluble also in alcohol ; but ether and oil of turpentine do not take up any sensible quantity of it. Concentrated sulphuric acid poured upon salicin gives it a beautiful red colour, very similar to that of bichromate of potash. This property is not confined to salicin in a state of purity ; but holds in solutions containing no more than ^-^^jth of their weight of this principle. Hence it may be employed to ascertain whether any bark contains salicin. It dissolves in muriatic and nitric acids, without becoming coloured. The solutions of salicin are not precipitated by nutgalls, gelatin, acetate, or diacetate of lead, alum, or tartar emetic. When boiled in excess with lime- water, no combination takes place ; nor is it capable of dissolving oxide of lead. When heated a few degrees above the temperature of boiling water it melts, and, on cooling, assumes a crystalline form. When thus treated it loses no water ; but if the heat be raised it assumes a lemon-yellow colour, and becomes brittle like resin. t It does not combine with acids, or possess alkaline properties. ,(;il:. * Jour, de Pharm. xvi. 242. + Ann. de Chim. et de Phys. xliii. 440. See also Hoff, Jour, de Pharmacie, xvii. 169. X Pclouze and Jules Gay-Lussac, Ann. de Chim. et de Pliys. xliv. 220. 240 ALKALIES ANALYZED. ! : : ( Its constituents, (kterniined bv the analysis of Pelouze and J. Gay-Lusvac, are :- - Carbon ..... Hydrogen Oxygen 55-49 (j-38 38-13 ./if- 100-00* As we do not know the atomic weight of salicin, we cannot de- duce from this analysis the number of atoms of which it is comp'f-d. But C* H^ O"'* gives an .approxiniii'ion of the smallest numho' of atoms which correspond with the ab.ve analysis. And C"i IP O" comes still nearer to it. riie first would gi\o G-3V5 for iho atomic weight, and the la!^it, 15-625. According to Herberger, the salicin of Loroiix is a -alt con - posed of a peculiar acid, combined witli Ihe true ^-.I'icin, wlii ■ii pos- sesses tlkaline properties. It may b(^ oiitained by dissolving ordi- nary sallt'in in oxalic acid, and separating the oxalic aciii by means of limo- It cryL-Uillizes in prism.s, restores the blue coloiir of re^Meiied litmus jiaper, dissniv(\^ in alcohol and water, and comljine:"? with acids. He and Bu> hncr formed the sulpiiate, nitrate, pliosphale, acetate, tartrate, oxaiu. mxl inurla*o of salicin. These salts are soluble in alcohol, but rot in ether. They melt when heated, and most of them may be obtit'ned in crystals. The acid of ordinary salicin is volaiile, and uj.iy be distilled over.f Brac.mnot found salicin in the bark of the salixjissa, amyQiialina and helix. And M. B4 or 1 atom ; iil ''f . ir.-ono or per ront. fi4'l8 1-1 r, — — 7-48 Oxygen 21 '7.0 or 5 atoms = 5M) — — 21-38 loo-oo* aa-MTrj loo The jjumresin olitaincd l>y M. Couerbe, wliilo jtiirifylnjj vora- trina, as doscrlbed in tlic last Section, is a substance of a reddish colour, and very soluble in water. When heated '^, t I tliiiik it prol)al)lo that thebaina does not exist ready Ibrmed in o])iiim ; but that it is evolved liy tiie action of lime on inor|)liinii. I Couerbe eonsidors tliis mode of obtaininir morpliina as more eronomical tlian tlie common one. Tiie nior))iiina thus obtained may be converteii into sulpliate without previous solution in alcohol. aci at( is ] nilCUAlNA. 345 4K 38 i(T vor same as (loiii^e- o had the the year » of ;>flra- id it in the which we ina from ' aqueous )re(.'i\)itate n alcohol, rplilna, a a current had hecn lid a good :allizes in protuhcr- isolated, \\ prisms, it melts, 1338°, and li at 194°. tituents of oiiiuni ; but Umical tlian ito suliiliate Wlioii the crystaU of thcbaiiia an; iiiolt( ley jfive out 4 per cent, of water. It will l»e seen iininediately that the utoUi of thebainu in 2<)*75. Hence the crystals consist ot 1 atom thehaina . . . 20*75 I atom water . . . l'12r) M. Couerbe subjected it to an analysis in the usual way by means of oxide of copper, and obtained Carbon Tl'DTO or 25 atoms = 18*7.0 giving percent. 71'44 Hydrogen (i-JliO or 14 atoms = 1*75 — — ()*G() Azote 6*385 or 1 atom = 1*75 — — i'rtUt li3*17y or 4atoin8= 4*00 — — l(]-24 Oxygen lOO-OOO* 2(J*75 10()-0() M. Couerbe found that 323 parts of tliebaina absorb 27 parts of dry muriatic acid, and in anotlier '>xperiment that (iO parts absorb 5 of muriatic acid. If we consider the salt fhus termed as a bimuriate, we h.ive the atomic weight of thehaina 2()*75. It was analyzed in 1830 by Mr. Kane of "Dublin, who obtained (Carbon .... 73*20 Hydrogen .... 0*85 Azote ..... 0*!)4 Oxygen . . . . 13*01 This gives the formula 25 atoms carbon 14 atoms hydrogen 1 atom azote 3 atoms oxygen lOO'OOt 18*75 or per cent. 74*25 l-7a _ _ 0*<>3 1-75 _ — 0*1)3 3-00 _ _ 11*8!) 25*25 100 This result differs from that of Couerbe by an atom of oxygen. According to Mr Kane, 100 parts of thebaiiia absorb 33*28 parts of muriatic acid. This would nuke the muriate a compound of Muriatic acid . . . 4*025 Thehaina .... 13*89 It would seem from this that the salt formed by Mr Kane was a compound of 2 atoms muriatic acid . . 9*25 1 atom thehaina . . . 25*25 34*5 My (Jouerbe's experiments 100 thehaina absorb only 8*35 of muriatic acid. His salt must have contained 2 atoms thehaina united to I atom muriatic acid. None of tlie salts of thehaina have been hitherto examined. Nor is its effect uiion the animal economy yet known. ♦ Ann. (le Cliiiii. ct dc Pliys. lix. I j(). f Aim. dcr'Phurm. xix. 9. * 'I ir 24(i Al KAI.IKS ANAl Y/Kli. U'l! Iff 1 m . ( SUCTION IX. — OJ' l>l':i,i'lllNA. |)('l|(liirm W.18 tllHcovDrcnl, iii lHl!>, l)y MM. Lartaaiij;no an«l I<'(!iuMill(!* ill till' Mcrtls of till' (Mphiniinti ufapfit/srKjriu m- sffiirsanr, 11 hioiiiiial plant, wliicli j^rows in tlie South of Miironc. 'I'lii; si-i'ds are u«iially importeil into tlii.s country from Italy, i'lu'v aro larj,'i?, roiijih, of an irrejjcular trian<;ular tijruro, and of u Mackish colour on the outsiilo but yellowish within. 'J'lieir aiiiell is disaifrooahlo and somewhat fii'tid : to tlii' taste they are very hitter, aerid, and nau- seous. The aiu'ients seem to have employed them as a masticatory. They are sel(h)m used now-a-days except as an external appliciition in s(tnie eruptions, and to destroy lice. M. Coiierlie proposes the following' method of extractinj: delphina from thesi! seeds :t — They aro pounded in a mortar, and thus hrouijht into the consistence of a paste. This paste is dJL'Csted in hoilinj,'' alcohol, of the specific gravity ()'R;J7, till everythini; soluhio is taken uj). The alcohol is distilled otf and a lackiah-red extract left, containinjf much fatty matter and very acrid. Let it be boiled ill water acidulated with sulphuric acid till it ceases to communicate any colour to that licpiid, or til' lo precipitate is thrown down by an alkali dropt into it. The delpiiuia is held in solution in the state of an impure sulphate, and a \hich will din- milvc the delphitia. Treat tin; solution with ivory black, fdter and precipitati! the delphina by atnnu)nia. It has the form of a jelly. Hein^r disMolved in alcohol and obtained by evaporation it af^sunics th(! form of a crystalline povvih-r, whicli bocoines opaiiue when dried. Delphina has a alight and)er •olouv. It is aolid, soluble in ether, still nu)re soluble in alcohol, but scarcely sohd)le in water wluither cold or hot. The taste is excessively adi.l, and it re- mains very louy in the nu)uth. It does not crystallize. It melts at 248". At u higher temperature it underjroes decomposition and is charred. The dilute acids dissolve it without alteration ; but concentrated ucids decompose it. Nitric acid at the eomnu)n temperature of the atniosj)here has but little action in it, but when boated it alters its properties and converts it into a bitter and acid resin. Chlorine at the usual temperature of the air has no action on it, but at the temperature of 300° or .320", it attacks delphina with violence, j^ives it first a green colour and then a brown, and renders it very friable. Muriatic acid is formed, and the matter formerly soluble in alcohol is now only j)artially so. Ether dissolves an ad- ditional portion, and a powder of a deep chestnut-brown colour re- mains undissolved. ( 'ouerbo found that 100 delphina absorbed 17 '52 of umriatic acid, making the muriate Muriatic acid . . . 4*025 Delphina .... 2 for the atomic weight of delphina. from the analysis of delphina by Couerbe* and Henry, f its con- stituents are (-arbon Hydrogen Azote Oxygen Coiiorbe. Henry. | 1 7r>-<).5 8-89 5-93 9-53 77-55 ^ 8-81 .o-r>8 8-0() 1 00-00 100-00 or 27 atoms = "20-25 or per cent. 77-14 or 18 atoms = 2-20 — — S-51 or 1 atom = 1-75 — — ()'(i7 or 2 atoms = 2-00 _ — 7-62 20-25 100-00 Deljjhina combines w ith acids and forms salts, which have an ex- tremely bitter and acrid taste ; but only a very few of them have been examined. 1 . Muriate of delphina. This salt deliquesces when exposed to the atmosphere. 2. Sulphate of delphina. Ac(!ording to M. FeneuUe, there art; two species of this salt, neutral sulphate and disulphate of delphina. * Ann. Hi. Cliiin. ct dr rii)s, lii, 36(i. i .luui. . (i'i. fl fi> : I 4i* m% IP Ml Ifel :ii'iii 248 ALKALIES ANALYZED. v i When delphina is saturated with sulphuiic acid and the solution is left to spontaneous evaporation we obtain a transparent hard mass resembling' gum, which dissolves readily in water and in alcohol. The taste is at first bitter, and then acrid, and the impression re- mains long in the mouth.* 3. Nitrate of delphina. Delphina when saturated with weak nitric acid forms a colourless solution, which becomes yellow when concen- trated. By evaporating to dryness we obtain a yellow crystalline mass. 4. Oxalate of delphina is obtained in white plates, having the same bitter and acrid taste as the other salts of delphina. SECTION X. — OF NARCEINA.f This substance was discovered by Pelletier, in 1832.^ It may be obtained from opium, in the following manner : — Let opium be digested several times in cold water, till every thing soluble be taken up. Evaporate the aqueous liquid to the consistence of an extract. Dissolve this exti*act in boiling water : a brilliant crystalline matter remains undissolved, which is nareotin. Raise the aqueous solution to the boiling temperature, and add ammonia till it is in slight excess. Boil for a little, to drive off this excess as much as possible, then allow the liquid to cool. Abundance of morphina falls in the state of crystals ; while a crust of morphina, mixed with a matter, apparently resinous, swims on the surface of the liquid. The greatest pf.rt of the morphina being thus separated, the remaining solution is concentrated to one half of its bulk, and set aside in a cool place. An add'tional precipitate of morphina falls. Barytes water being added to the liquid thus freed from morphina, * M. Feneullo has analzyed three diftbrent sulphates of delphina (Jour, do Pharinacie, ix. 5). I. Sulpiiate by digesting an excess of delphina in dilute sulphuric acid, filtering and evaporating to dryness. It was composed of Acid . . . 3*0;H or 5 or 1 atom. Deljjhina . 95'9G9 or 139-9G or 6 atoms. •J. Sulphate composed of Acid Delphina ,3. Supersulphate of delphina Acid Delphina 100-000 1 '7 16 or 5 or 1 atom. 98-284 or 28*3-3 or 1 1 atoms. 100-000 6*438 or 5 or 1 atom. 100 77-6 or 3 atoms. 106-4:38 But these analystj cannot bo depended on. \ Named probably I'mm vajxn Inrpnr. \ Ann. do Chiiu, ct k\c V 1. Ul. NARCEIN.A. 24!) the the and hina una. 3ur. de jilteriii!; [IV, a precipitate oi meconate nf barytes falls, wliich is io bo separated by a tilter. To the remaining liquid carbonate of ammonia is added, to throw down any excess of barytes that may have been introduced. Keat the liquid thus freed from barytes, and drive off the excess of car- bonate of ammonia, and evaporate it to the consistence of a thick syrup. When brought to this consistence it is left for some days in a cool place. It assumes the form of a pulpy mass, among which crystals may be observed. This pulpy matter is put upon paper to dry, and then strongly pressed between folds of cloth to free it from a black viscid matter. It is now digested in boiling alcohol, which partly dissolves it. The alcohol being distilled off, and the residual liquid allowed to cool, crystals are deposited, which are easily purified, by repeated solutions in water and crystallizations. These crystals constitute narceina. Should it be mixed with meconin, this last substance is easily separated by digestion in ether. Narceina has a white colour, and silky lustre. It crystallizes in delicate four-sided prisms, having the aspect of needles. It has no smell ; its taste is slightly bitter, and it gives an impression similar to what one perceives when he puts his tongue between two metallic plates of zinc and silver, and the two plates are brought into con- tact. It dissolves in 230 times its weight of boiling water, and in 375 times its weight of water of the temperature of 57°. When heated to 198° it melts, and on cooling concretes into a white translucent mass, exhibiting vegetations on the surface, which show a tendency to crystallization. At 230" it becomes yellow, and when the heat is increased it is decomposed without subliming. The concentrated mineral acids act upon narceina with great energy, and quite alter its nature. When the same acids are in a dilute state it combines with them; but it does not prevent them from reddening vegetable blues. Wlien muriatic acid, diluted with one third of its weight of water, is placed in contact with narceina, the alkaloid assumes a fine blue colour. If we add enough of water to dissolve the compound, the solution is colourless. If we evapo- rate this solution, we obtain a violet-red crust, which passes at last into blue, if the liqui'l does not contain too much acid, in which case the crust is yellv w, but the narceina is altered in its nature. When the blue colour is pr(^duced, the narceina is unaltered, for it may l)e precipitated with all its properties by an alkali. If we jibs( . J the water from a muriatic solution of narceina, by means of chloride of calcium, w. can obtain the red, violet, and blue colours in succession. The dilute sulphuric and nitric acids produce the same pheno- mena as the nmriatic. The peroxldized salt-? of iron do not strike a blue with nnrceina. VV(> have f wo analvsos of narceina, one bv Pelletior, and the other i \l u ■ iiJH h; bv ( oueriio The results are as follow: 250 ALKALIES ANALYZED. Carbon Hydrogen Azote Oxygen Pelletier.* i C'oucrbc.t or 28 atoms = 21*00 or per eent. 5()'38 or 20 atoms = 2-50 _ _ (i-U or 1 atom = 1'75 — — 4*70 or 12 atoms = 12-00 _ _ 32-21 10000 100-000 37-25 100 This would make tlie atomic weight 37*25, which, from analogy, ought to be pretty near the truth, admitting the accuracy of Couerbe's analysis. When narceina is exposed to a temperature above 230° it swells, gives out vapours, at first white, and afterwards yellow, and leaves a bulky charcoal. We find iu the receiver an acid licjuid, a brown bituminous liquid, having a balsamic odour, together with some white crystalline needles, which seem to be crystals of gallic acid.J SECTION XI. — OF COUEINA.§ This substance was discovered in opium by M. Kobitjuet, in 1832, while occupied in examining the process of Dr Robertson of Edinburgh, for extracting morphina from opium, by means of chlo- ride of calcium. II This method consists hi macerating opium in water, concentrating the infusion, and mixing it with chloride of calcium. Meconate of lime precijjitates, while iuuria*.is of morphina and codeina remain in solution. These salts are obtained in crystals, by concentrating the liquid sufficiently, and the crystallizations are repeated till the salts are quite white. They are then dissolved in water, and the morphina precipitated by annnonia. The codeina remains in the solution. To obtain it the residual li([uid is concentrated, and a crystalline mass obtained, which is pressed between folds of blotting paper, and digested in boiling water. A portion only dissolves, which, as the liquid cools, is deposited in silky tufts of crystals, perfectly white. When these crystals are treated with a solution of caustic potash, a ])ulverulent liydrate of codeina h deposited, which is first washed in a little cold water, and after being dried, is digested in boiling etlier, A portion of the powder is dissolved, and the liquid, when evaporated spontaneously, deposits small radiated plates, which are hard and transparent, and at last a licjuid remains of the consis- tence of syruj). W hen a little water is added to this liquid, a num- ber of white crystals are deposited in needles. These are collec- ted on a filter, and washed witli a little water. When dried they * Anil, do Chim. et do Phys. !. 2G8. f Ibid. lix. 151, t IVlletier, Ann. do Cliim. I't de I'hvs. 1. '267. ^ NaiiiL'd |ii()liulily tiom Koiir,, ihc tVtnt of the poppy. |i Ann. dc Clijiii ci dc Tlivs. li. ':?59. CODEINA. 251 constitute pure codeina. 100 lbs. of oj)iuni yield about six ounces of it. It has been hitherto very imperfectly described. When ex- posed to heat on platinum foil it ''urnf! with Hame. When heated in a tube it melts at 302 ", and on cooling concretes into a crystal- line mass. It possesses alkaline properties. 1000 parts of water at ,59° dissolve l2-() parts of it; at 110", .'57 parts; and at 212", 58-8 parts. When added in excess to boiling water, it gives out its water of crystallization, and then melts, assuming the appearance of an oil. Codeina is insoluble in alkaline solutions. It combines with acids, and forms salts, several of which crystallize. The nitrate in par- ticular crystallizes very readily. The tincture of nutgalls occasions a copious jnecijjitate in solutions of codeina. Hi/driodafe of codeina is a white salt, which may be obtained bv dissolving codeina directly in hydriodic acid. It is very similar to hydriodatc of niorphina, but cannot, like it, be decomposed by ammonia. Iodic acid dissolves codeina ; ])ut Pelletier did not suc- ceed in obtaining the iodate in crystals, except there was an excess of acid present. The crystals were Hat needles.* Nitric acid does not change codeina to red as it does morj)hina ; nor docs it strike a blue with the persalts of iron. Couerbe analyzed muriate of codeina, and found it composed of Muriatic ac^d . . . 4-025 Codeina .... 36*25 Kolti(juet found that 100 parts of codeina crystals contain ()'5 \\;itcr. Ilenco they arc composed of 1 atom codeina . . . 3(i*25 2 atoms water . . . 2*25 m 38-5 According to M. O. Henry, tannate of codehia is couipos'u < f Tannin . ' . . 02 or 59-14 Codeina ... 38 or 3()-2 lOOf Now, 3.' atoms of tannin = .>8*1878. It would soeii^. liorefore, as if this salt were composed of 3^ atoms tannin, and 1 atom codeina. Robi(piet| and Couerbe § siibjected codeina to an ultuuate ana- lysis, and obtained for its constituents Ami. do Cliim. et dc Phys. Ixiii. 194. ■\ .loiir. do Plianiiacio, xxi. '1-1\. Ann. do Chilli, et do Plivs. li. ^IGo. 5? Ibid. iix. I J8. ^1 t\ n '\v. B!,'. '11 If ' 1 I i 252 Carbon Hydrogen Azote Oxygen ALKALIES ANALYZED. Itobiguet. Coucrbe- 71-339 72-846 7-585 7-148 5-353 5-231 15-723 14-775 100-000 100-000 or 32 atoms = 24-0 giving 72-4() or 19 atoms — 2-375 7-17 or 1 atom = 1-75 5-28 or 5 atoms = 5 15-09 33-125 100-00 Dr William Gregory has made some experiments on the action of nitrate of codeina on the animal economy. When administered in doses of from 4 to (i grains, it produces an excitement, similar to into::ication, which in a few hours is followed by a disagreeable depression, accompanied by nausea, and sometimes by vomiting. M. Kunkel has remarked that codeina loses a good deal of its activity wlien combined with acids. Hence it is probable that a simple aqueous solution of codeina would be more active than the nitrate.* SECTION Xll. — OF STRYCIININA. Strrdmina was discovered, in 1818, by MM. Pelletier and Ca- ventou.f It exists in the seeds or fruits of several species of strych- nos, particularly in the mix vomica, the fruit of the strychnos nux vomica ; in St Ignatius' bean, the fruit of the strychnos iynatia, and in that of the strychnos colubrina or snakeivood. It was found also in the poisonous matter called upas, which the natives of the Indian Archipelago employ to poison their arrows. P'roiu St Ignatius' bean Pelletier and Caventou extracted strych- nina by the following process : — The beans were grated down to a kind of powder, and then di- gested in ether as long as any soIulIo matter could be extracted. Tlie residual matter was treated a great many times successively with boiling alcohol. The alcohol being distilled off, a yellowish- brown matter remained, having an exceec' . gly bitter taste, and soluble both in water and alcoiiol. When this substance was treate 1 with caustic potash a precipitate was obtained, which, after being washed in cold water, furnished a white crystalline matter, having an exces- sive bitter taste. It was strvchnina. To obtain strychnina from nux vomica, an alcoholic extract is obtained, which is dissolved in water. To the solution diacetato of lead is added as long as any precipitate falls. The strychnina remains in solution, united to acetic acid. The solution contains, besides, colouring matter and an excess of the diacetate of lead. This excess is thrown down by sulphuretted hydrogen, and the liquid is then boiled with magnesia, whicli precipitates the strych- nina. It is washed in cold water, and dissolved in alcohol which frees it from the magnesia employed in excess. When the alcohol is evaporated, the strychnina is obtained in a state of purity. It is by u similar process that it is obtained from snakewood. * ,](Ha'. <1(' 'I'lMiiiiiU'ie, XX. 85. t .Jour, fk- Pluiiiiuieic, v. 17;.), uml Am:. il'.' ('liiiii, cl i!<.' I'liv X. 14-_>. STUYCHNINA. 253 7-17 5-28 15-09 00-00 action stered iirailar eeablc ig. M. ,ctivity simple tratc* nd Ca- strych- los nux 'ia, and .ud also Indian stryeh- then di- tractetl. essively Uowisli- soluble e I with washed 11 cxces- Itract is liacetato lyclinina lontains, )f lead, land the «trych- [\ which alcohol . It is nig M. Henry* extracts strychnina from nnx vomica, by the foUow- nr process: — Tlie nnx vomica is grated down to powder, and treated with water till every thing solnl)le is extracted. These de- coctions being eva])orated to the consistence of a syrup, lime in a pulverized state is added, care being taken to employ it in slight excess. The lime forms an insoluble salt with igasuric acid, which seems to exifst in nux vomica combined with strychnina. It preci- pitates the strychnina, and some other substances. The digestion, with lime, is continued for several hours. The precipitate is then washed, and digested in alcohol of the specific gravity 0-827, which dissolves the strychnina and some colouring matters. The alcohol being distilled off by the water-bath, the strychnina is obtained in brilliant crystals, together with a small quantity of dark-coloin-ed liquid, containing some strychnina. By repeatedly dissolving these crystals in alcoliol, or still better, by combining them with nitric acid, crystallizing the nitrate, dissolving the crys- tals in water, and throwing down the strychnina by annnonia, it is obtained pure. 1000 parts of nux vomica, by this process, furnish 5 or G parts of strychnina. M. Henry, junior,t has proposed the following process, which he considers the best of all those hitherto proposed : — Nux vomica is reduced by grinding to a fine powder. It is di- gested under the heat of the water-bath with alcohol of the specific gravity 0-85(5, and acidulated with sul])huric acid. For e\ery kilogramme (1.5433 grains) of nux vomica, 40 to .50 grammes of sul- phuric acid and from 4 to .5 litres of alcohol must be employed.^ Or for every avoirdupois pound weiglit of nux vomica, add 280(j grains, or about 10 drams of sulpliuric acid, and 111 cubic inches, or rather more than 3 imperial jiints of alcohol. Two digestions in alcohol take place, and the residual undis- solved nux vomica is $id)j(>cted to jjressure, and all the alcoholic liquids being mixed together, an excess of quicklime in powder is added, sufficient to saturate the acid and to throw down the colouring matter. The alcoholic liquor, which has a light-amber colour, is decanted oti" the precipitate. The precipitate is washed with alco- hol, and all the licjuids are carefully filtered, and the alcohol is dis- tilled off. There remains a greenish-brown, pitchy alkaline matter, which is to be saturated with water weakly acidulated with sulphu- ric, muriatic, or acetic acid. The neutral licpiid is filtered, con- centrated, and precipitated cold, by adding a slight excess of am- monia. The preci})itate which fiills is washed, and digested in hot al- chol, of the specific gravity 0-!)42, in order to dissolve the hrucina. The strychnina is then dissolved in boiling alcohol of 0'837, and treated with a little animal charcoal to remove the colouring matter. When the liquid is allowed to cool the strychnina crystallizes. * .T'liir. tie Pliarmacie, viii. 401. f Il)i(). xvi. 75-2. J Tlie grainiiic is I,V433 grains, and tlip litre coiitaiiis Gr028 cubic inches. ill 254 AI,KAI.IES ANALYZED. According to Wittstock,* lib. of mix vomica yields 40 oraiiit; of nitr.itc of strychnina, and 50 grains of nitrate of brucina, when treated in the following way : — Boil the nux vomica with alcohol of the specific gravity 0*94. Decant off the liquid, and dry the nux vomica in an oven. It is thus rendered easily pulverizable. Digest the powder in alcohol, till every thing soluble is taken up. Distil off the alcohol, and treat the residual liquid with acetate of lead, as long as a precipitate con- tinues to fall. By this process the colouring matter, the fatty matter, and the acids present in the solution are separated. Throw the whole on a filter, wash the dcjjosit, and evaporate the liquid, till for every pound of nux vomica employed, there remains from 6 to 8 ounces of liquid. Add 2 gros of magnesia,t and allow the mix- ture to remain at rest for some days, that the brucina may have time to be deposited. Collect the deposit on a cloth, expose it to pressure, dry it, and digest it in alcohol of 0*813. When the alco- hol is distilled the strychnina is deposited in the state of a white crystfilliae powder, while the brucina remains in the mother water. When strychnina is obtained by the spontaneous evapvivUion of an alcoholic solution, it assumes the form of octahedron-, composed of tw<) four-sided j)yramids, between which a four-sided })risni i'? ^/iii'Hnnes interposed. Its taste is intensely bitter, and it leaves an impression in the mout' imilar to that produced by certain metallic salts. It is des.iruro of smell. It acts with great energy on the animal economy, being a most virulent poison, and ])roving equally fatal whether it be taken into the stomach, or mixed with the blood by being introdu;!ed into a wound. Death ensues very rapidly, often in a few minutes. It oc- casions violent contractions of the muscles, and induces tetanus. The best antidote is infusion of nutgalls, or warm tea. But its ac- tion is so rapid, that it is seldom in our power to apply any remedy. In small doses (^'^jth grain) it has been tried in paralysis, and, it i'" said, sometimes with success. It undergoes no alteration when exposed to the air ; and docs not melt nor lose any weight when heated up to 248". It is decom- posed when heated to about (500°. It requires 2")00 times its weight of boiling water, and ()G07 times its weight of cold water to dissolve it. But this last solution, weak as it is, has a decidedly bitter taste. Anhydrous alcohol does not dissolve it. At the temperature of (iO", alcohol of 0-820 disisolves only a trace of it. Alcohol of 0'83;5 dissolves r- sensible ([uantity of it at the boiling temperature. It is scarcely soluble in ether. The volatile oils dissolve it, and when a boiling solution is allowed to cool, part of the strychnina II bitter taste, but dissolve very little of it. •qui * Berzeliiiti's Traile de Chiinie, v. 142. f The u:ros is 7'2 grains. SrUYCHNlNA. 255 when : 0-04. It 13 ilcoliol, 111 treat ite con- le fatty Throw ^uid, till ■oni () to the mix- lay have ,ise it to the alco- • a white !!• water, ivvtion of tomposeil prism i'' on in the ts. It is i(r a most aken into ;;ed into a (S. It oc- is tetanus. \h\t its ac- \,' remedy. and, it'!"* docs not lis doconi- GG7 times [ion, weak ll does not dissolves (juantity it, and Ltryt'hnina ive (lissoi ve iraui'' M. Pelleticr formed tlie iodide of strychnina, by triturating the alkali with half its weight of iodine, digesting in water, filtering, and dissolving the brown residue in boiling alcohol. The solution had an orange colour, and deposited small yellow crystalline plates, resembling Mosaic gold. These crystals consisted of iodide of strychnina. Towards the end of the evaporation, white needle- form crystals fell, consisting of muriate of strychnina. Iodide of strychnina is insoluble in cold, and very little soluble in boiling water. It is but little soluble in alcohol of 0-817. Its best solvent is boiling alcohol of the specific gravity 0-837. It crystal- lizes on cooling. Ether does not dissolve it. At first it seems tasteless, but some bitterness and astringency becomes o-radually perceptible. It is infusible at the temperature of 212°, and at every temperature below that at which it undergoes decomposition. When heated on platinum foil it swells, softens, emits iodine, and is charred. Very dilute acids have no action on it while cold, but decompose it by long boiling. Nitric acid, when concentrated, diseng.ages iodine without the assistance of heat. Sulphuric acid acts in the same way, but with less energy. Muriatic acid has no action while cold ; but when assisted by boat it disengages iodine. Potash and soda, when aided by heat, disengage stryclmina, while an iodide of ])ot.issium or sodium is formed. Ammonia has no action on it. r L'Uetier analyzed this iodide, and found it composed of 1 atom iodine . . . 15*75 1 atom strychnina . . . 31 40-75* We have three analyses of strychnina, one by Pellctier and Dumas, another by I^icbig, and a third by Henry and Plisson. The following table exhibits the results of these analyses : — roUetier & Diiinast LiebiK. t I Henry & Plisson.^ Carbon 78-22 75-35 7G-4 Hydrogen G-54 6-70 7-8784 Azote 8-92 5-81 7-503f) Oxygen 0-38 12-14 8-2190 100-OG 100 100 I^iebig found that muriatic acid.ll He of . ...^. 100 parts of strychnina absorbed 15-02 Hence muriate of strychnina is a compound of Strychnina . . . 30-792 Muriatic acid . . . 4-G25 According to this experiment the atomic weight of strychnina is 30-792. Ihit, in another experiment, he finds that 100 strychnina * Ann. dc Chiin. ct ilo Phys. Ixiii. \G5. f Ibid. xxiv. 180. i I'oggendorf's Annaleii, xxi, 21. § Jour de Pliannaeie, xvii. 433. II Poggendorfs Annulcn, xxi. 21. . , 'U ir III It i ii I LI W. t i! III! j ■ :■ r ' 25fi Al.KAMES ANALYZED. absorb H'fi imiriHtic acid.* This would misc tlic atoniic weight to 31-74. By another analysis he found suljdiate of strychnina composed of strychnina 8()-102, and sulphuric acid l.'}*828.t Hence the con- stituents are Strychnina . . . . 31*13 Sulphuric acid ... 5 The mean of tliese analyses gives 31*22 for the atomic weight of this alkali. Now, the number of atoms which agree best with the preceding analyses is the following : — 30 atoms carbon = 2'2*o() or per cent. T()"{)3 1() atoms hydrogen = 2-00 _ — ()-84 1 atom azote =1-75 — — 5-98 3 atoms oxygen =: 3-00 — — 10-25 2!)-2.5 100-00 But they do not coincide with the atoniic woiyht. Doubtless the atomfi of oxygen in strychnina are 4, and not 3, as Liebig has suj)- posed. When heated strongly, strychnina swells, blackens, gives out an eni])yreumati(' oil, and a little amnioniacal water. It gives out car- bonic acid and carburetted hydrogen, while a bulky charcoal re- mains behind. When a mixture of strychnina and sulphur is luatod, the strych- nina is docomiHised, and a great cpiantity of sulpluu'otted hydrogen gas is evolved. When a mixture of .■strychnina and iodine is boiled in water, the colour of the iodine disappeiirs, and the strychnina is dissolved abundantly, assuming, in the first j)lace, a red colour. When a current of chlorine is pas.-ed through water, holding strychnina in suspension, the latter is dissolved ; and when the solution is evaporated, \mni crystals of nun-iate of strychnina are obtained. The salts of stryclmina have been more examined than those of any of the other alkaloids. Tliev are all solu])le in water, h.ive an intensely bitter taste ; and when taken into tlu; stomach, or intro- duced into the circulation, prove fatal, by inducing tetanus. When nitric acid is poured ujion a salt of strychnina, and heat applied, the ^alt assumes a beautiful red colour ; but this is owing to the presence of a foreign matter. They are preei])itate(l by the infu- sion of nutgalls, and the precipitate is soluble in alcohol. 1. Miiriote of stnjchuinti. This salt crystallizes in very line needles, usually grouped together in tufts. When ex])ose(l to a dry atmosphere, these crystals become oj)a(pie. This salt is pretty soluble in water. When heated to tlu; temperature at which the base beirins to be decomposed, it lets go the nnu'iatic acid. VN'hen corrosive sublimate is poured into a solution of niuriat(? * Ann (le Ciiiiii. it (l(; I'liv^ xlix. 24."). Ibi.l. ( -' \Y '.r^^vt.i.^^.>.4^,^i;as}K?;?Ksai»' ~wrc STRYCHNINA. 257 eight 5C(l of I con- o-ht of [•cding ess the las sup- j out an o\it car- Lry fine jmI to a U pretty liicli the luiriate of strychuina, a ilouldo salt Is de])osited iu white flock". Tlie cyanodide of uiereiiry produces au analogous deposit. 2. fli/ffriodate o/sfri/r/itu'uff. This salt crystallizes in white Hat needles. It is so little soluble in cold water, that it precipitates when a solution of iodide of potassium is dropt into a salt of strych- uina. Its taste is bitter, and from the experiments of Peilctier, it appears to he a compound of 1 atom hyilriodic acid, and 1 atom strvehnina.* h. [Ji/drori/miafe ofstryvhninn. This salt is obtained by dissolv- iuff strychuina in prussie acid. It may be evaporated to dryness without losing its acid. 4. Siilphnte of stn/chninn. This salt crystallizes in cubes, and requires ten times its weight of water to dissolve it. Its taste is ex- quisitely bitter, and it is deccmiposed by all the salifiable bases which throw down the strychuina. This salt loses its water when heated to 21 2». If we add a little sulphuric acid to a neutral sulphate of strych- uina, evaporate to dryness, and digest the residue in ether to remove the excess of acid, we obtain a hisiilphatc of strychnina, which crystallizes in fine needles, and has a taste at once bitter and acid. f). Cupreous sulphate of strychnina. This salt may be obtained by boiling strychnina in a solution of sulphate of copper, filtrating the liquid, which has a pale-green colour, and crystallizing. The salt forms long needles, having a green colour. (j. Nitrate of strychnina. To prejjare this salt, we must dilute nitric acid, and heat it with a greater proportion of strychnina than is sufficient to saturate it. When the liquid is evaporated, it yields crystals of nitrate of strychnina in pearl-coloured needles, grouped together in the form of stars. Its taste is excessively bitter, and it acts with more violence on the animal economy than pure strych- nina. It is much more soluble in hot than in cold water. When heated a few degrees above 212" it liecomes yellow, and undergoes decomposition. If we increase the heat the salt swells, blackens, and a noise is heard similar to that of nitre in a state of fusion. But no light apjjcars if the salt be neutral. This salt is slightly soluble in alcohol, but insoluble in ether. If to a hot saturated solution of nitrate of strychnina we add a little nitric acid, crystals of hinitrate ofsfrychuina are deposited as the ]i(piid cools. They have the form of very fine needles. When heated they become red, and by augmenting the temperature they are de- composed with a kind of detonation and evolution of light. Pelle- tier and Caventou have shown, that this red colour is owing to the presence of a small quantity of foreign matter derived from the nux vomica and attached to the strychnina. In the upas there is a similar matter, but it is converted into green by nitric acid, in- stead of into red. m h' * Ann. do Cliiin. ot, di; Plivs. Ixiii. 172. m 2.")H AlKAI.ir.S ANAI.YZFI). 7. Cnrbonate o/\sf/i/rhntii/t. This salt iiiay ^w olitaiiiod by niix- ind prisms. When i; prepare i; iiy dissolving strychnina in phosj)li"iiC acid, the li(piid still retaitis the ])roperty of reddening veget Mf blues. Hut this does not hinder the four-sided prisms IVum heing deposited. Probably they constitute a biphosphate. f). Chlorate qfstrf/chtiiiia. This salt may be obtained by saturat- iny dilute chloric acid with strychnina. When the solution is heated it becomes coloured, and the salt crystallixes in small short ])risms. If the solution is concentrated, it becomes almost a solid mass on cooling. 10. lodate of strychniua. When a solution of iodic acid is heated moderately in contact with strychnina, it assmnes a wimvred colour. When the concentrated solution is left in a cool place, it deposits transparent crysta.s in long needles in tufts, suj)erficially stained red, but rendered "olourless when wasluvl on a filter with a little cold water. They are very soluble in water, and are decomposed when suddenly heated. From the analysis of Pelletier, it appears that this salt is com- posed of 1 atom iodic acid and I atom strychnina.* 11. According to M. (). ilenrv, tannale of strychnina is com- posed of Tannin . . . (V.Vd^i or 54-<)4 Strychnina . . .*J(i'07 or 31 lOO'OOt It is, therefor-*, a vc uutrj.'vto. 1 2. The acetic, tartaric- and oxalic acids, form with strychnina neutral salts, very soluble in water, and more or less capable of as- suming regular crystalline forms. SECTION XIII. — OF BIIUCINA. Brucina was discovered by Pelletier and Caventou, in 1811), in the bark of the hrucea antidysenterica.X This bark has been intro- duced into medicine as a substitute for angustnra, and had been dis- tinguished by the name oi false anr/usturo. Brucea was named from Druce, the Abyssinian traveller, who first brought the seeds of the shrub from Abjssinia, and they afterwards vegetated in the botanic gardens of Europe. Brucina was afterwards detected along with strychnina in mix vomica, and has been found in general to accom- pany that alkali in the different vegetable bodies which contain it. Pelletier and Caventou extracted 6/-MCJ/(1 when is coin- is com- •yclinina le of as- 1819, in bn intro- peen dls- lied from Is of the botanic tuff with accom- lain it. ^ustuva, si. 221. Irk of the in the followin^^f way: — A kil(K'ramnie ('2} lbs. avoirdnpoirt) of the hiirk reduced to a marsc powdtM', was (lii,fested in ether to remove ill.* greatest part of tlie ,itty matti^r wliicli it contains. It was then ^ examined. Narcotina may be introduced into the humai stomach without producing any deleterious or even sensible effect. Orfila adminis- tCiCd it to the amount of several drams a-day, in various forms, with- out perceiving any action whatever. When about 2 scruples of it, dissolved in oil, were given to a dog, it was very speedily fatal. Smaller doses kill more slowly, bringing on a stupor from which the animal never recovers. Acetate of narcotina is almost without effect on dogs, the acid having the property of destroying its poisonous qualities. SECTION XVII. — OF MORPHINA. Morphina may be obtained from opium by the following process : — Macerate any quantity of opium in twice its weight of water for * Aniiiilen dcr Pliarmacie, vi. &a. ^i mm 968 AKKAIJE8 ANAI.Y/KD. if i twenty-four hours, agitating the mixture occasionally to promote the solution. Decant off the solution, and pour over the undissolved portion a new quantity of distilled water, equal to the portion first employed. Repeat tiiis process four times, or till everything soluble in cold water be taken up. If the opium bo of good quality, about three-fourths of it will be dissolved, and the remaining fourth re- mains in a solid state. Filter the solutions thus obtained, and eva- porate the whole to dryness in a low heat, to prevent any portion of the residue from being decomposed or injured. Pour distilled water upon this dry residue. The whole will dissolve except a bril- liant crystalline matter, which is narcotinn. Heat the solution to the temperature of 212°, and add to it ammonia in slight excess. Boil the mixture for ten minutes, to drive off this excess, and then allow the liquid to cool. The morphina precipitates in crystals, pretty pure. But a portion of it swims on the surface, mixed with impurity. If the morphina thus obtained be digested in sulphuric ether, a portion of narcotina is dissolved, and the morphina is ren- dered more pure. It may be rendered quite pure by dissolving it in boiling alcohol, digesting the solution with some Ivory black, filtering and crystallizing. This process should be repeated three or four times, in order to free the morphina of all impurity. An easier mode of purifying it is to dissolve it in sulphuric acid, taking care to avoid adding an excess of the acid. By evaporation the sulphate of morphina is obtained in crystals. Let this salt be decom- posed by digesting it with magnesia. The sulphate of magnesia is washed off, and the morphina, which is mixed with the excess of magnesia employed, is to be dissolved in boiling alcohol, and crys- tallized. Various other methods of procuring morphina have been proposed, but the preceding appears to be on the whole the easiest. Opium yields at an average about iVi^h of its weight of pure morphina. Morphina has a white colour, and is usually crystallized in very small four-sided prisms, sometimes terminated by four-sided pyramids. Its taste is very bitter and astringent; but it has no sensible smell. It is insoluble in cold water ; but boiling water dissolves about Y^jjth of its weight of it, and allows it to fall in crystals as the solu- tion cools. It dissolves in 40 times its weight of cold, and 30 times its weight of boiling alcohol. It dissolves also in fixed and volatile oils, and may be fused with camphor. But ether scarcely dissolves it. The crystals are always small. The primary form, according to Brooke, is a right rhombic prism, the ftices of which meet at angles of 127° 20', and 52" 40'. The acute edges are usually replaced by tangent planes, converting the figure into a six-sided prism. The base of the prism is usually concealed by two faces, which meet at an angle of 95° 20'.* • Brooke, Annals of Philosophy (Second Series), vi. 118. MORPHINA. 269 ) promotu ndissoWed jrtion firat ng soluble ility, about fourth re- (l, anil eva- y portion ot ur distilled Lcept a bril- solution to ight excess. ss, and then t in crystals, , mixed with in sulphuric phina is ren- dis&olvinji it ivory black, epeated three npurity. An c acid, taking aporation the salt be decom- 3 of magnesia i the excess of .hoi, and crys- jeen proposed, siest. Opium morphina. allized in very ided pyramids, as no sensible lissolves about lis as the solu- imes its weight )latile oils, and solves it. The lino- to Brooke, [t at angles of Illy replaced by Id prism. The n which meet at The transparent crystals of niorpiiind contain, nccordinfl^ to Lie- big, (J I per cent, of water. Wlu»n heated this water flies oft*, and the crystals become opatpio, and white?. If we raise the temperature the morphina melts, and forms a yellow li(iuid, which becomes wiiite, and crystalline when allowed to cool. When still farther heated in contact with the air, it gives out a resinous odour, smokes, and burns with a vivid red flame, giving out much smoke, and leaving a charry residtic. Caustic potash, or soda ley, dissolves morphina. These alkalies, of course, cannot be employed in throwing it down from the infu- fcion of opium. Caustic annnonia dissolves it also, though in nmch smaller quantity. We ought, therefore, when we employ ammonia to throw down morphina, to take care not to add too great an excess of that alkali. From the experiments of Pelletier it appears that iodine forms only an ephemeral combination with morpluna. When the two are triturated together, a reddish-brown powder is formed, which soon becomes black, the iodine being disengaged, and the morphina altered in its properties. At the same time hydriodic acid is formed.* When morphina is taken into the stomach in a solid state, it has been found to have but little action, probably on account of its little solubility in water ; but when in solution it nets with considerable energy. It has been tried in solutiim in olive oil and alcohol ; but the best solvents are the acids, — acetic acid, muriatic acid, and sul- phuric acid, answer very well. When these salts are taken in small doses of from ^ to ^ grain, they act as sedatives. In larger doses they produce the symptoms of intoxication, and occasion dele- terious and even fatal eflects when given to the amount of 6 or 8 grains. Morphina has been subjected to analysis by heating it with black oxide of copper, and collecting the products. The following table exhibits the analyses that seem to have been made with the greatest care : — Bussy.t Ilcnry *: riisson.l Pelletier & Uuma^i ^ Erandcs.ll Lieblg.U Moan. 69-0 6-5 4-.V 20 70-52 7-9884 4 7860 16-7056 72-02 7(il 5-53 14-84 720 5-5 55 170 7 1 -364 6 '559 4-GOO 17-471 71-340 6-494 5-131 17035 100 100-0000 100-00 100-0 100-000 100-000 Carbon Hydrogen Azote Oxygen If we adopt (instead of the mean) Liebig's analysis, the formula for morphina will be * Ann. tie Chim. et de Phys. Ixiii. 185. f L. Gmelin's Handhuch, ii. 937. J Jour, de Pharmacie, xvii. 453. § Ann. de Cliini. ct de Phys. xxiv. 185. II L. Gmelin's Handbucli, ii. 987. \ Poggendorf's Annaien, xxi. 17. 118. 270 It i ALKALIES ANALYZKr). 34 atoms carbon = ^H'li or por cent. 7 1 "83 IH iitonirt hydrogen = 'i-'i.') — — fi-.'H 1 ntoni nzoto = l'7.'5 — — 4'n3 6 utoinH oxygen = <» — — 1(M)0 3fl'5 100 To (loterminc the ntomic weight of morphiim, Liehig passed a current of dry nuiriutic acid over (JOO parts of it, till the gaf» ceased to ho absorbed. The muriate thus formed weighed Cud parts, and was perfectly neutral. It was dissolved in water, and the muriatic acid thrown down by nitrate of eilver. The chloride of silver obtained weighed 2!)H.* The atomic weight deduced from the increase of weight of the morphina when saturated with muriatic acid is .'Wi'.'>l That from the weight of chloride of silver is .'J(i'*24 2)72-75 Mean .•5()-3 75 iviean ....... Liebig, in order to corroborate the accuracy of these experiments, subjected the sulphate of morphina to analysis. It was crystallized, dried in the open air, and then heated in a temperature of 248°, till it ceased to lose weigjit. '•'••" ••"°"i» "f •"" """i" lows: — eii iii.:(iiuii ill (I tuiiiiii;! fitiii v: kji ^-iii , I'he result of his analysis was as fol- Mor|)hina Sul])huric acid Combined water Water of crystallization 75'.'i8 or 30-48 10-;i3 or 5 4-(JC or 2-25 9-03 or 4-06 100-00 ,5 being the atomic weight of bulplmrlc acid, it is obvious that 36-48 is the atomic weight of morphina. This approaches very near the deduction from the muriate. Indeed, if we assume the composition of the muriate as indicated by the increase of the weight of the morphina, when saturated with muriatic acid (which is most sus- ceptible of accuracy), the two very nearly agree, and give us for the atomic weight of morphina the number 30-5. It has been observed above that the transparent crystals of mor- phina contain 0^ per cent, of water. It is obvious from this that they are composed of 1 atom morphina . 30-5 or 94-19 2 atoms water . 2-25 or 5 81 38-75 100-00 The small excess of water obtained by Liebig was doubtless liy- grometrical water. Many experiments have been made to discover a ready mode of * Poggenclorf's Annalcn, xxi. 18. f MOnPIIINA. 271 passed he ffiw A (57 <» Br, and iliioride t of tlio 75 >rimcnt9, rttivUizcd, of 248°, as aa fol- Ihat 36-48 near tlio Imposition tht of the lOSt sus- (Ve U3 for Is of mor- thia that [btleaa hy- mode of detecting morphina, and diatinj^uishinjf it from other budien. When this alkaline substance, or any of its salts is placed in contact with a neutral solution of a neutral salt of peroxide of iron, it strikes a blue colour, as was Hrat obsorved by M. Robiiiet. The addition of a slight excess of acid causes tlfn colour to disappear immediately. The addition of too much water causes tlm blue colour to pass into red.* Nitric acid changes the colour of morphina into orange-red, which gradually passes into yellow. Hut as this acid produces the same alteration on brucinaand its salts, we cannot depend upon this character. SeruUat, pointed out iodic acid as an excellent reagent for de- tecting morphina. When a solution of iodic acid is brought in con- tact with a little morphina, or acetate of morphina, the liquid assumes a reddish-hrown colour, and exhales the peculiar smell of iodine. A very minute quantity of morphina (y^nth of a grain for example) is sumcient to produce a sensible ette. Bisttlphate of morphina. This salt may be obtained by adding sulphuric acid to the neutral salt, and digesting the whole in ether, to remove any excess of acid that may have been added. It has an acidulous taste, and contains just twice the acid in the sulphate.* 6. titrate of nmrphina. When dilute nitric acid is saturated with morphina, and the solution evaporated, needle crystals are de- posited in stars, soluble, according to Choulant, in 1^ times their weight of water .f 7. Phosphate of morphina. The phosphate of morphina, accord- ing to Pettenkoffer, crystallizes in cubes. When the salt contains an excess of acid, the crystals are needles conjjected in bundles. 8. Acetate of morphina. Morphina dissolves readily in acetic acid, and when the solution is concentrated, the acetate crystallizes, with difficulty, in short prisms, easily soluble in water, but less soluble in alcohol. This salt is apt to lose a portion of its acid, even when kept in crystals ; and during the evaporation crystals of morphina are sometimes deposited. This salt is employed in medicine on the Continent in preference to every other ; but in Edinburgh the muriate of morphina is pre- ferred. 9. According to Choulant, tartrate of morphina crystallizes in oblique prisms. § * Pelletier and Caventou ; Ann. de Cliim. et de Pliys. xii. 122. t Gilbert's Annalen der Phys. Ivi. 318. % Il)id. 348. BrJ Ri cai foiiil dur ATROPINA. 273 10. Pectate of morphina may be obtaiiicil by digesting pectic acid, still moist with morphina and water. The base and acid dissolve, and the salt precipitates in the state of a jelly when alcohol is poured into the solution.* 1 1 . Meconafe of morphina. There is reason to believe that it is in combination with meconic acid that morphina exists in opium. But this meconate has never been obtained in the state of crystals ; nor indeed have its properties been examined. ;| 12. Tannate of morphina. It is a white powder, composed, ac- cording to M. O. Henry, of Tannin . . . 59*81 or 54-31 Morphina . . . 40-19 or 30-5 lOO-OOt It is therefore a tertannate. 13. Kinate of morphina. Does not crystallize, but forms a gummy transparent mass, dry on the surface, but moist internally.| The salts of morphina have been hitherto but superficially ex- amined. They have all a strong, bitter, and disagreeable taste. Their aqueous solutions are precipitated in flocks by the alkaline carbonates. Ammonia produces no precipitation in dilute solutions of these salts when aJd-jd in excess ; or if a precipitate fall, it is again redissolved. They are not precipitated by infusion of nut- galls, unless they contain narcotina. SECTION XVIII. OF ATROPINA. The first attempt to analyze the leaves of the atropa belladonna, or deadly niyht-shade, was made by Melandri, in the year 1808. § He found in them oxalates of lime and magnesia, chloride of potas- eiam, resin mucus, extractive, and a substance which he called animal extractive. Vauquelin examined atropa belladonna, in 1809,11 and detected albumen, a bitter nauseous substance, to which he ascribed the narcotic properties of this plant, and a number of salts of potash. In 1819, M. Brandes detected in this plant a vegetable alkaloid, which he distinguished by the name of alropina, and the properties of which he described pretty minutely.^ Succeeding experimenters not being able to obtain this alkaloid by the method described by Brandes, called in question its existence altogether. But M. Runge, in his experiments on dattirina, an alkaloid exceedingly re- sembling, if not the very same with atropina, explained the reason of this want of success, by showing that it was decomposed by the caustic alkalies, even when very weak.** Hence it is obvious, that * Braconnot. f Jour, do Phannacie, xxi. 22 1. X Henry and Plisson, Jour, de I'liariuacie, xv. 40(i. § Ann. de Chiui. Ixv. 2-22. || Ibid. Ixxii. u'.i. % Scluvoigijer's Journal, xxviii. 9. Tiie paper, translated into linglisli, will Ijo foniKJ in the Ann:ils of Pliiiosopliy {Second Series), i. 203, See aUo Annulen dcr Pljarmacie, i. 08, 2;J(). *• Ann. dc Chiui. et de Pliys, xxvii. 32. T 'iii i'\ fil! !'; ': m I II m I I 274 AI,KAI,1ES ANALYZED, no caustic alkali, how weak soever, should ever be employed in the preparation of atropina. In 1833, atropina was obtained, and its properties examined by MM. Geiger and Hesse.* But M. Mein Goders was the first person who obtained it in a state of purity .f The process recommended by M. MeinJ for obtaining atropina from the roots of the atropa belladonna, is as follows : — Let 80 parts of the roots of belladonna, coming from plants from two to three years of age, be reduced to a very fine powder, and digest- ed with 00 parts of alcohol, of the specific gravity 0*830, for several days. The alcohol is then to be separated by subjecting the matter to strong pressure in cloth. Let an equal quantity of alcohol be poured on the powder, and let the mixture be treated as before. These tinctures being mixed together and filtered, one part of slacked lime is added, and the whole is left in a close vessel for 24 hours, and then filtered. Sulphuric acid is now added, drop by drop, till there is a slight excess. Sulphate of lime precipitates, which must be separated by the filter. Distil off the half of the tincture or rather more ; and add to the residue from 6 to 8 parts of water, and heat till the alcohol be dis- engaged. Concentrate the liquor with great caution, till it is re- duced to one-third of its bulk. When it is cold, add to it, drop by drop, a concentrated solution of carbonate of potash, as long as a precipitate continues to fall. If the liquid contains much atropina, it usually (after a few hours' rest) assumes the form of a gelatinous mass. Filter, and add more carbonate of potash to the liquid which passes through, till all the atropina be thrown down. The matter left to itself gradually as- sumes the form of a jelly, and exhibits frequently on its surface, or in the mass, white stars of crystallized atropina. By agitation the gelatinous matter separates from the mother water, which is got rid of by pressing it between folds of blotting paper. Were we to attempt to wash it in this state a great portion of it would be lost. We must allow it to dry, and then making it into a paste with water, squeeze out that liquor, by placing the paste be- tween folds of blotting paper. The residual matter is now dried, and dissolved in about 5 times its weight of alcohol. Filter the solution, and add from (i to 8 times its volume of pure water. This addition renders the liquid milky, or at least, it becomes so when the excess of alcohol is evaporated. In 24 hours the atropina will be found deposited in crystals of a light-yellow colour. After washing them in a few drops of water, these crystals are dried upon blotting-paper. We obtain from 1000 ])arts of the root of bella- donna, by this process, about 3 parts of atropina. Atropina thus obtained has a white colour, and is crystallized in transparent prisms, having a silky lustre. It is destitute of smell. It is solul)le in absolute alcohol and in ether, and much more soluble in these liquids when hot than when cold. Cold water dissolves * Aiiiialtii (ior IMiartnario, v. 4.'<. f Ibid. vi. 07- X Jour, do I'lianiincie. xx. 87 ; or Amialon tier I'liui in. vi, 07. ATKOiMNA. 275 in the id its Mein ty.t ropina 3 from iigest- several matter )bol be before, part of for 24 irop by pitates, d to the I be dis- it is re- drop by mg as a !W hours' idd more ill all the ually as- rface, or ation the is got rid tion of it ig it into paste be- )\v dried, 'liter the ;er. This SI) when »pina will After l-ied upon of bella- fvUized in of smell. Ire soluble dissolves about y^ijth of its weight of it ; but it is more soluble in hot water. The solution has a very disagreeable bitter taste, and restores the colour r ■tmus paper reddened by an acid. When applied to the eye ev: n a very dilute state, it speedily dilates the pupil, and tne dilivjtion continues for a considerable time. It is not volatilized at the temperature of boiling water. But at a higher temperature it melts, and is converted into vapours, which are deposited like a coat of varnish. Heated in the open air it melts, gives out empyreuraatic vapours, becomes brown, and finally, burns with a yellow flame, and giving out but little smoke. Chlorine has little action on it. With the acids it combines in definite proportions, and forms salts. Its constituents, according to the analysis of Liebig,' areas fol- lows : — Carbon 69-84 Hydrogen . . . . 8-14 Azote ..... 7'52 Oxygen .... 14-.50 100-00 M. Liebig found, that 100 parts of atropina, dried in the air, absorbed 18-9 parts of muriatic acid. The atropina became hot, and melted into a yellow transparent matter, which was completely soluble in water. This experiment gives 24*47 for the atomic weight of atropina. Liebig considers atropina as composed of 92 atoms carbon = 16*5 or per cent. 71*34 1 5 atoms hydrogen = 1*875 — — 8*11 1 atom azote = 1*75 — — 7*57 3 atoms oxygen = 3*00 — ~ 12-98 23-125 100-00 These atomic proportions make the atomic weight less than that deduced from the muriate of atropina. This, indeed, is generally the case. But the ultimate analysis is susceptible of greater ac- curacy than that of the salts. The salts of atropina have been examined by MM. Geiger and Hrandes. I. Muriate of atropina. It forms brilliant crystals, which are either cubes or square plates. The salt is soluble in water and al- cohol. Composed of 1 atom muriatic acid . . 4-625 1 atom atropina . . . 24-5 29*125 2. Sulphate of atropina. Atropina, when heated with concentrated sulphuric acid, is decomposed and blackens. Dilute sulphuric acid dissolves it without alteration, and the sulphate crystallizes, though II ill m r5 I 484 Ann. der Pharmacio, vi. GO. I m:^ 276 ALKALIES ANALYZKI). the crystals are so small and irregular that their shape has not been determined. The salt dissolves in between 4 and 5 times its weifrht of water. It is soluble also in alcohol. When exposed to the air, it loses its water of crystallization. When strongly heated, it un- dergoes decomposition, and becomes black. According to Geiger and Hesse, 100 parts of atropina are just saturated by 13*87 parts of sulphuric acid.* If we consider the salt as a compound of 1 atom acid, and 1 i atom atropina, the atomic weight of atropina will be 24. 3. Phosphate of atropina. When atropina is dissolved in phos- phoric acid and the solution evaporated, the salt assumes the ap- pearance of gum, which deliquesces when exposed to the atmo- sphere. 4. Tartrate of atropina. When dried, forms a colourless tran- sparent mass, which did not crystallize, but absorbed some moisture from the atmosphere. Nitric, acetic, and oxalic acids dissolve atropina, and form acicular salts, all soluble in water and alcohol. Nitric acid acts much less powerfully on atropina than on strychnina.f The action of chloride of gold, slightly acid, when dropt into an aqueous solution of atropina is characteristic. The precipitate at first formed is lemon-yellow ; but when allowed to remain for some time it assumes a crystalline structure, and is probably a compound of chloride of gold and muriate of atropina. The aqueous solution of atropina is precipitated white by the in- fusion of nutgalls, and isabella-yollow by chloride of platinum. M. Brandes likewise obtained alkalies from seeds of hyoscyamus niger and the datura stramonium, to which he gave the name of hyoscyaminaX and daturina.^ But these two bodies approach so near atropina in their properties, that I think it likely that a more minute examination will show that they are identical. There are reasons for believing that the Turks are in the habit of administering preparations of these plants to those individuals whom they wish to render idiots. 1| SECTION XIX OF CONICINA. This is the active principle of conium maculatum, or hemlock ; and is next to hydrocyanic acid, the most virulent poison at present known. Geiger seems to have been the first person who obtained it in a state approaching to purity. A set of experiments proving its alkaline properties, and adding considerably to the facts already known, was published in 183() by MM. Boutron-Charlard and O. Henry,^ and considerable light has been thrown upon its action * Annalen der Pharmacie, vi, 52. f Brandes, Annals of Philosophy (Second Series), i. 264. X Sehwei^gcr's Jour, xxviii. 91, and Annalen der Pharmacie, i. SS.I. § Jour, de Pharmacie, vi. 47, and 230. See also Geiger and Hesse, Ibid. xx. 94 ; and M. Bley, Annalen der Pharmacie, iii. 135. Ij Jour, de Pharmacie, xx. 117. t Ann. de Chim. ct de Phys Ixi. 337. m CONICINA. 277 not been ts weifrbt ) the air, ed, it un- o Geiger j'87 parts of 1 atom la will be i in phos- es the ap- the atmo- rless tran- e moisture and form ; acid acts opt into an jcipitate at in for some , compound 3 by the in- ;inum. hyoscya7ntts le name of proach so lat a more In the habit 1 individuals nlock ; and tent known. Ined it in a Proving its ks already larlard and its action i. 333. kse, Ibid. xx. Iivs Ixi. 3i57. on the animal economy, by Dr. Christison of Edinburgh, in a paper published in the 13th volume of the Transactions of the lioyal Society of Edinburgh. According to Brandes,* it may be obtained in the] following manner : — Digest fresh hemlock in alcohol, add magnesia, or hydrate of alumina, or hydrate of lead to the solution, and distill off the alcohol. Evaporate the residual liquid to dryness on the vapour-bath. Treat the residual matter with a mixture of alcohol and ether, which will take up the conicina. Evaporate this solution to dryness, and digest the residue in ether. When the ether is evaporated, it leaves an extractive substance of a light yellowish-brown colour, and a dis- agreeable smell. Giesecke, in order to obtain conicina, mixes the expressed juice of conium with magnesia, and distils. The ammoniacal liquid which comes over is neutralized with sulphuric acid, and evaporated to dryness by a gentle heat. The dry residue being digested in absolute alcohol, the conicina is dissolved, while the sulphate of ammonia remains. Conicina thus obtained gives a flesh-coloured precipitate with tincture of iodine. It is precipitated of a dirty-white colour, by acetate of lead, nitrate of mercury, and nitrate of silver. Tannin throws it down brown. A grain of it was sufficient to kill a rabbit. Geiger succeeded in isolating from hemlock, a volatile alkaline poisonous substance (doubtless true conicina), by the following process : — Mix fresh hemlock with potash and water, and distil as long as what comes over has any smell. Neutralize this product with sul- phuric acid, evaporate to the consistence of a syrup, and dilute it with anhydrous alcohol, as long as sulphate of ammonia continues to separate. Separate the liquid portion from this salt, distil off the alcohol, mix the residue with very strong potash ley, and distil anew. The alkaline substance conicina passes along with the water into the receiver. It has the form of a yellowish-oil, has a strong smell analogous at once to that of hemlock and of tobacco, and an exceedingly acrid and bitter taste. It is solub'e in water, and combines with and neutralizes the acids. It even smokes slightly like ammonia when brought near the volatile acids. It possesses marked alkaline properties, and neutralizes acids. It is poisonous, and so are its salts, but in a less degree. The sulphate of conicina does not crystallize. It undergoes an alteration by exposure to the air, both when un- combined and when united to acids. When saturated v/ith an acid it assumes a red-colour, which the alkalies destroy. Houtron-Charlard and Henry succeeded in freeing conicina from ammonia, with which it is at first mixed, by washing it in dis- tilled water. Thus purified it had the following properties :— * Br. Arcli, xx. 111. ill IS IS I ■J- '' ,1' 1 Ji^i ii 8 * 278 ALKALIES ANALYZED. I I- It has the appearance of yellowish liquid oil. It dissolves com- pletely in alcohol and ether. It is lighter than water, and is slightly soluble in that liquid. Its smell is strong and penetrating, and recalls at once that of hemlock and of tobacco. Its taste is acrid and corrosive, and it occasions death almost as rapidly as prussic acid. A single drop put into the eye of a rabbit, killed it in nine minutes. Three drops used in the same way, killed a strong cat in a minute and a half. Five drops poured into the throat of a small dog began to act in thirty seconds, and in as many more, motion and respiration had entirely ceased. MM. Boutron-Charlard and Henry found conicina possessed of decided alkaline characters. It dissolves in the acids, and is capable of neutralizing them. With sulphuric, phosphoric, nitric, and oxalic acids, it forms salts, which crystallize in prisms of a con- siderable size. During the saturation of these acids, the liquids assume a bluish-green colour, which gradually passes into reddish- brown ; and when these salts are evaporated, whether by means of a gentle heat, or by placing them in vacuo, over sulphuric acid, they lose a part of their base, as happens with the ammoniacal salts. The salts of conicina absoi'b moisture from the atmosphere very rapidly, and they are soluble in alcohol. When conicina is placed in vacuo, along with substances which rapidly absorb moisture, it is partially volatilized, and leaves a reddish ^pitchy-like matter, very acrid, and which Boutron-Charlard and Henry consider as anhydrous conicina. The vapour of conicina is inflammable. It occasions white fumes when placed near a glass rod dipt in muriatic acid. When the salts of conicina are dissolved in water, they give, with pure tannin, a white curdy precipitate, soluble in alcohol, and very bulky. Conicina, dissolved in alcohol of the specific gravity 0*87 1, gives, with iodic acid, a copious white precipitate, similar to that which the same acid forms with quinina, cinchonina, strychnina, and brucina. It appears, from a note to Boutron-Charlard and Henry's paper,* that conicina has been analyzed by M. Carbon (i6"91 or 12 atoms == Hydrogen 12'00 or 14 atoms = Azote 12-80 or 1 atom = Oxygen 8-29 or 1 atom = Liebig, 9 1-75 1*75 1 who obtained or per cent. lOO-OOf 13-5 6G-67 12-9() 12-9() 7-41 100 SECllON XX. -I'AIULLINA. This alkali was detected by Pallotta, in 1825, in the root of smilax mrsaparilla, or the common sarsuparilla of the shops.| His process was as follows : — * Ann. 'if ( ;hiin. rl ile I'liys. Ixi. 340. f Pogjrendorfs Animleii, xxxvii. ;,'0. 4. Brugnatelii's (iioni. xvii. 386, and Jour, de Pharinacie, x. .'i4a. MECONIN 279 jonicina is The roots, reduced to powder, were boiled with six times their weight of water, and the decoction was repeated with fresh water till every thing soluble was taken up. These decoctions were filtered and mixed with a quantity of milk of lime, with which they were frequently agitated till they acquired alkaline properties. The grey precipitate obtained in this way was washed and dried, and boiled for two hours with alcohol of the specific gravity 0*817. This pro- cess was repeated with fresh alcohol till every thing soluble was taken up. The alcoholic decoctions were filtered, distilled, and the residual matter left at rest till the parilliua was deposited. Parillina thus obtained is a white })owder, not altered by exposure to the air. It has a peculiar smell, and a bitter and sharp taste, slightly astringent and nauseous. It is precipitated from its solu- tions by chloride of calcium and by the mineral acids. It gives a brown colour to turmeric paper, fuses when heated to 257°, becomes black, and is partly decomposed. When placed upon a red hot iron plate it behaves like a substance destitute of azote. Concentrated sulphuric acid decomposes it. It is insoluble in cold and but little soluble in hot water. It dis- solves in alcohol. It neutralizes dilute sulphuric acid and other acids, and forms salts. It is only slightly soluble in cold alcohol, but it dissolves readily in boiling alcohol. Parillina was analyzed by M. Christian Petersen, who obtained Carbon (i2'80 or 9 atoms = (rT5 or per cent. G2*79 Hydrogen 9' 14 or 8 atoms = 1 — — 930 Oxygen 28-0() or 3 atoms = 3 — — 27-91 100-00* 10-75 100-00 Pallotta tried the effects of parillina upon himself. When swallow- ed to the extent of 13 grains it occasioned nausea, vomiting, di- minished the rapidity of the jmlse, and acted as a sudorific. It is obvious from this that it is a debilitant. Falchi states that if the pith of sarsaparilla be macerated in water, and the solution, after having been treated with ivory-black and filtered, be left to si)ontaneous evaporation, small light-yellow crys- tals separate, which are slightly soluble in alcohol, have but little taste, yet leave a strong imjjression in the throat, and give a green colour to syrup of violets. To this substance he has given the name oi smilacina.^ Its properties have scarcely been examined. SECTION XXI. — OF MECONIN. Meconin difl'ers from all the preceding alkaline bodies, except parillina, in containing no azote. On that account I think it doubt- ful whether it be really an alkali. This has induced me to leave to it the name meconin, by which it is known on the Continent, and to place it at the end of the analyzed alkaline bodies. it- ,«- Mr , 4 IF"!, m n IF' ft II i Ami. dor I'liiiiiiuicic, \\, "I, f Borzeliiis, Tnute dc Chiuiic, v. 188. w<- ' ■ 280 ALKALIES ANALYZED. It was discovered by M. Duhlanc, junior, in 182G. It was after- wards discovered anew by M. Couerbe, in 1830, who was un- acquainted with the previous examination of it by Dublanc* It may be extracted from opium in tlie following manner : — Cut the opium into small pieces, and digest it in cold water till that liquid ceases to acquire any colour from it. Filter the aciueous solution and concentrate to the sjjecific gravity of 1'05. Add .iramonia, previously diluted with 5 or (i times its weight of water, as long as a precipitate continues to fall. This preci])itate is com- ])lex, but consists chiefly of raorphina. Decant off the liquid portion after a few days, and wash the precipitate with water as long as the liquid continues to be coloured. All these liquids being mixed are to be evaporated in a gentle heat, to the consistence of a syrup, and left in a cool place for 14 or 15 days. A crop of granular crystals is gradually deposited. Decant off the liquid portion, and dry the crystals, after they are as well freed from the mother water as possible, in a gentle heat, hav- ing previously subjected them to pressure between folds of blotting paper. The crystalline mass obtained is brown or fawn-coloured. Re- sides raeconin it contains some other substances, ])articularly nar- ceina. Digest it in boiling alcohol, of the si)eciHc gravity 0*837, till every thing soluble be taken up. Distil off the alcohol till the solution be reduced to one-third of its original bulk. On cooling, it deposits a quantity of crystals which contain mcconin. Hy farther concentration more of these crystals may be obtained. Subject these crystals to the press. Dissolve them in boiling water, digest the solution with animal charcoal, and filter. The crystals now deposited from the solution are nearly white ; but they still contain narceina. Treat tliem with ether, which dissolves only the meconin. IJy si)ontaneous evajjoration, mcconin is de- posited from this licjuid in a state of purity. Opiunj yields about .j^'fjo^'^ of its weight of meconin. Meconin is white and destitute of smell. When first put into the mouth it has no taste, but soon imparts an impression of acridity. It is soluble in water, alcohol, and ether, and crystallizes very well froi^ all these solutions. The crystals are six-sided prisms, termi- nated by dihedral summits. When heated to 194° it melts, and assumes the form of a colour- less limpid fluid. At 311° it may be distilled over without any alteration, and, on cooling, concretes into a hard mass having the aspect of tallow. '•It requires 2G5| times its weight of cold water, and only 18i times its weight of boiling water to dissolve it, as determined by the experiments of Couerbe. When digested in water the liquid be- cojnes opaline as it heats, the crystals lose their shape and swim in • Ann. i\c Cliiii) ft (Ir I'livs. I. ■J.j.'!, ami ."l:!?. MECONIN. 281 isr the flocks upon the surface of the water. When the heat approaches the boihng point of water the nieconin nssunica the appearance of coloiirlcss drops of oil, which gradually dissolve.* Sulphuric acid, diluted with half its weight of water, dissolves it without the assistance of heat. If we heat the solution, oven gently, the ineconin is altered ; green streaks make their apjjearance, and, in a short time, the whole liquid assumes a fine deep-green colour. If we now mix it with alcohol it becomes rose-red ; but when the alcohol is driven off by heat, the green colour again appears. Water throwD down from the solution a brown flocky matter, which does not redissolve in the dilute acid, even when assisted by heat. But it is dissolved by concentrated sulphuric acid when assisted by a gentle heat, and the solution is green. It is insoluble in water, but easily dissolved by alcohol and ether, to which it communicates a deep-red colour. Acetate of lead, when dropt into a solution of meconin, occasions no precipitate ; but the diacetate throws it down, and forms with it a kind of chemical compound. Potash and soda dissolve meconin, but do not appear to form a chemical compound with it. Ammonia does not dissolve it, and carbonate of ammonia throws it down from its solution in caustic potash or soda. When treated with nitric acid crystals are obtained which possess the characters of an acid, and which M. Couerbe, who discovered it, has distinguished by the name of hyponitromeconic acid. When a current of chlorine gas is passed over meconin in fusion, the gas is absorbed, and a substance is formed at first red and then deep-yellow. By this action two distinct substances are formed. The first is white and crystallizable, and hit: been distinguished by M. Couerbe, who discovered it, by the name of chloride of mech- loic acid. The other substance has a resinous aspect and a yellow colour, contains much chlorine, and may be separated by boiling the product with carbonate of soda. Meconin does not possess alkaline pro])erties, and does not seem capable of combining in definite proportions with acids. Its crystals contain no water of crystallization, for lli.^y may be kept in fusion for any length of time without any loss of weight. Wc are thrt^©- fore ignorant of the jj.tomic weight of tl.is substance. Bui it contains no azote, and when subjected to analysis by Couerbe he obtained from 1 part of meconin '2'241 parts of carbonic acid and 0*462 parts of water. This gives for its constitution, per cent. * Carbon 01*03 or 10 atoms = 7*5 or percent. 6 1 'SO Hydrogen 5* 13 or 5 atoms = 0*()25 — — .5*15 Oxygen 33-84 or 4 atoms = 4*0 — — 32-99 lOO-OOf • Ann, do Chini. ct ^ •It i m 284 AI.KALIB»« IMI'RnFRCTLY EXAMINED. ay contain. And the liciuid being decanted oft', is distilled by a gentle heat. The ether passes over into the receiver, while the nieotina does not begin to rise till the temperature be raised to 212°. Nieotina obtained in this way has the consistence of honey, an acrid taste, and a brown colour. To obtain it perfectly pure it must be distilled in an oil-bath, at the temperature of 284°. MM. (). Henry and Boutron- Charlard obtained it by the follow- ing process : — A pound avoirdup; '^ of tobacco, togetliei' .vir!? ^32 cubic innbes of water, and {'y^^ ounces avoirdupois of .'tUf^u s., la were j ..it into a cucurbite. A moderate heat was first Ujjpiicd, and then the liquid was made to boil. What distilled over was received into a glass vessel, containing rather more than an ounce of sulphuric acid, diluted with three times its weiffht of water. When about 150 cubic • J r. de PI, niacie, xiii. 37!). 4. iciiweiggir's Jour, x.xxi. 442. t Ann. (Ic Cliim. Ixxi. 189. 5 Mag. I'lmrni. xxiv. 13S. NICOTINA. t86 tho in- i rttato It was . Tho ])luHt9.t olerablc lined it, xtracteil A'ith 8iil- i\v lioat, boliiiioT), c(l lim«' ,tcr, con- r it with jr. The upon t\»o (listilleil )ortion of arc to be y, and is im of tlie led off, is receiver, Irature be [loney, an pure it le follow- [\r ir>"bes J .It into ^be litiuid a glass Lric acid, 1 50 cubic Ixxi. 189. Viv. 138. inclicM liavo passed over, the jtroeesH is stopped. The pro(hiet (which nui.st Im» k"pt slij^htly acid) is evaporated (h»wM to about I.IDO grains. It is the i allowed to cool, to separate a small deposit. It is to he filtered, imxcd with an excess of caustic soda, and diiiilled in a small retort, A colourlc^-' volatile Tupiid is obtained, wliicli i* concentrated in vmm to the con^istiMue of a Hjrup. 'This mattnw has an amber cnbuu*, and •; 'dually deposits snmll crystifUine pUiteis constitutinjf nicin la.* The crystals soon absorb moisture, and form a transpn "ont, «1- most colourless licpiid. I's smell, while cold, .< almost nothlnnf, but that of its vapour is similar to thai cd' tobacco, acrid and "lis- aj^reeablo ; and its taste is acrid and caustic, and contiiHies long in the month. It remains licpiid though cooled down to 21 >. It re- stores the colour of litmus paper, reddened by an acid, and renders turmeric paper brown. When heated to 212° it uives out a whiti; smoke, which tinges turmeric paper brown. At 375'^ it boils, and at the same time undergoes decomposition, bcconiing brown, as- suming the appearance of resin, and losing its acrid (|ualitics. Even at the ordinary temperature of the atmosphere, the air acts uj)on it, connnunieatingabrown cidour, and inducing inspi^sntioa and partial decomposition. It is difficult to make it burn uitb ttmne without using a wick. It then burns, giving a strong flu le, and emitting much smoke. Water dissolves it in all proportions, hither lissolves it also with facility, and when agitated with water, deprivt - that liipud of a great part of the nicotina which it holds in solutiu . Oil of tur- ])entine dissolves a little of it. It is soluble also in ahi.ind oil; when acetic acid is niixod with this solution it separates the m -otina. The alcolud solution of iodine destroys it, giving it at tirst a yellow, and finally a red colour. Its specific gravity is 1*048. When cautiously heated in a jjlatinum capsule, it may be volatilized in a white irri- tating vapour, without leaving any residue. This vapt ir catches fire at the approach of an ignited body. It contains a much greater proportion of azote than any of the other vegetable alkaloids. It has not been analyzed ; but its atomic weight is about 2()-25. Nicotina acts with great violence on the living body, being a most virulent poison. A single drop of it is sufficient to kill a mo- derate-sized dog. It possesses alkaline qualities, And neutralizes acid*. The salts of nicotina are distinguished by their taste of t( it)acco, and their acrid causticity. They are colourless, and geuerally soluble in water and alcohol ; but they do not seem to be soluble in ether. 1. Sulphate of nicotina. One part of common sulphuric acid requires 4'^ parts of anhydrous nicotina to saturate it. The salt crystaUizes with difficulty in plates. It has no smell, and is soluble in alcohoj. 2. Phvsphate of nicotina. It crystallizes, when concentrated to * Jour, tic Pharniiicic, xxii. 692. f1 ii; 286 ALKALIES IMPERFECTLY EXAMINED. i'ii i n > the consistence of a syrup, in plates, having some resemblance to cholesterin. 3. Acetate ofnicotina. This salt forms an incrystallizable syrup. When it is mixed with corrosive sublimate, or chloride of platinum, a double salt is formed, which precipitates, being but little soluble in water. 4. Oxalate ofnicotina. A very soluble and crystallizable salt. 5. Tartrate of nicotina. It is very soluble, and crystallizes in grains, the shape of which it is not easy to discover. The following are the effects of reagents on the aqueous solution of nicotina, as determined by Henry and Boutron-Charlard : — 1. Protosulphate of iron, a greenish precipitate, passing into ochre red. 2. Sulphate of copper, a greenish-white precipitate, not redis- solved by an excess of nicotina. 3. Phosphate of magnesia, a gelatinous precipitate. 4. Perchloride of iron, a brick-red precipitate. 5. Sodium chloride of gold, a copious orange precipitate. 6. Chloride of platinum, a yellowish granular precipitate. 7. Sulphate of zinc, a flocky precipitate. 8. Corrosive sublimate, a copious curdy precipitate. 9. Tartar emetic, a white precipitate. 10. Sulphate of manganese, white flocks. 11. Acetate of lead, a white precipitate. 12. Nitrate of silver, and cyanodide of mercury, O. The following table exhibits the quantity of nicotina yielded by 1 000 parts of various kinds of tobacco : — Cuba .... 8*64 Maryland . . . 5-28 Virsfinia . . . 10-00 11-20 He de Vilain Lot North Lot-et-Garonn For smoking 6-48 11-28 8-20 3-86 SECTION IV OF CURAUINA. This alkali was discovered, in 1828, by Boussingault and Rou- lin,* in a substance used by the Indians of South America to poison their arrows, and which is distinguished by the name of curara, or 7irari. Humboldt informs us that it is extracted by water from a species of strychnos, called in Soutli America mava cure. The aqueous extract is mixed, to give it consistence, with the mucilagi- nous extract of another plant. Curara may be taken into the stomach with impunity, but when introduced into a wound it occa- sions death in a few minutes. Tlie experiments of Boussingault and Roulin were repeated, and contirnicd, in 1829, by Pelletier and Petroz.f Curarina was obtained in tlic following manner : — Ann. de Cliim. ct do Phys. xxxix. 24. t Ibid. xl. 213. I IS COUYDALINA. •2S7 t occa- tuid 113. The curara was reduced to powder, and boiled in alcohol. The tincture being mixed with a littlo water, the alcohol was distilled off. The aqueous residue was decanted off a resinous precipitate which had fallen. It was digested with ivory black, and then precipitated by infusion of nutgalls. The precipitate, which was brown-coloured, and bitter tasted, consisted of a combination of tannin and curarina. It was washed with a little water, heated to the boiling temperature, and then mixed by little and little M-ith crystals of oxalic acid till the whole was dissolved. The acid liquor was treated with mag- nesia, which united both with the oxalic acid and the tannin, while the cm*arin remained in the solution. It was evaporated to dryness, and the dry residue was treated with alcohol, which left undissolved a small quantity of oxalate of magnesia. The alcoholic solution was evaporated, and the curarina dried in vacuo by means of sul- phuric acid. Curarina thus obtained constitutes a yellow-coloured, horny-look- ing substance, which is transparent when in thin plates, but has not the least tendency to form crystals, and which deliquesces when exposed to the air. Its taste is very bitter. When heated it is charred, and gives out the odour of burning horn. It is very soluble in water and alcohol ; but it is insoluble in ether and oil of turpen- tine. It restores the blue colour of litmus paper reddened by an acid, and gives a brown coiour to turmeric paper. It combines with acids, and forms neutral salts, having a bitter taste. The muriate, sulphate, and acetate of curarina, the only ones hitherto examined, are incrystallizable. Tannin alone, of all the reactives tried, has the property of throwing down curarina from its solutions. It is still a more active poison than the curara from which it was obtained. SECTION v. OF CORYDALINA. This alkali was detected by M. Wackenroder, in the root of the corydalis tuberosa, or fumaria bulbosa* It may be extracted in the following way : — The root, reduced to a coarse powder, is to be macerated in water for some days ; a deep-red infusion is obtained, which red- dens litmus paper. Let it be filtered, and mixed with as much alkali as will render it slightly alkaline. A grey-coloured precipi- tate falls, which is to be collected on a filter. The root remaining is subjected to a new maceration in water, acidulated with sulphuric acid, which dissolves a new quantity of corydalina. It is to be thrown down by an alkali, but not mixed with the former precipi- tate, because it is more diificult to purify. Let the precipitate be dried, and boiled in alcohol till every thing soluble has been taken up. Distil off the greatest part of the alcohol from this solution. Sometimes the residual liquid, on cooling, deposits a little cory- dalina in crystals. Eva})orate the liquid to dryness, and pour on the * Kastner's Arcli. viii. 417. il n m i I H i) Pi I 288 ALKALIES IMPERFECTLY EXAMINED. V ■ ■5 residutal matter very dilute sulphuric acid, which dissolves the corydalina, and leaves the green resinous matter. Precipitate the solution by an alkali, taking care to separate the dark-coloured matter which falls first, because it is impure matter. This being removed, the alkali throws down the corydalina white ; but it as- sumes a shade of grey while washing. When dry, it is a greyish- white incoherent mass, which stains the fingers. It has no smell, and little taste. It is very soluble in alcohol, and the more so the freer it is from water. The colour of the solution is greenish-yellow. Alcohol, when saturated with corydalina at the boiling temperature, lets fall, on cooling, colourless prismatic crys- tals, about a line in length. By spontaneous evaporation corydalina crystallizes in scales. The alcoholic solution of corydalina changes the colour of litmus, red cabbage, and roses, in the same manner as an alkali does. When exposed to the action of solar light, corydalina becomes deeper coloured, and assumes a greenish-yellow tint; and this change takes place more rapidly when the alkaloid is in the state of powder, than when in crystals. It melts when heated to 212°. The fused mass is translucent when in thin coats, and yields a crys- talline fracture. * If the temperature be elevated it becomes brown, Sfives out water and ammonia, and assumes the form of a brown translucent mass. It is very little soluble in water, but is easily held in suspension in that liquid by occasional agitation. When boiled with water it melts, and rises under the form of greenish-yellow drops, which swim upon the surface of the liquid. During the cooling the water becomes muddy, because part of the corydalina is deposited. Ether dissolves corydalina with facility. Caustic alkalies are better sol- vents than water, and the solution has a greenish-yellow colour. We must, therefore, beware of adding too nmch alkali when we precipitate this alkaloid from its solution in an acid. No attempt has hitherto been made to analyze corydalina. The salts which it forms with the acids have a bitter taste. 1. Muriate of corydaUna. Obtained by dissolving corydalina in muriatic acid. When the solution is eva])orated to dryness, an in- crystallizable salt remains, which is soluble in water, alcohol, and ether. 2. Sulphate of corydalina. When an excess of base is digested with dilute sulphuric acid, the liquid deposits, when concentrated by evaporation, a crystallized salt, which is but little soluble in water. If to an alcoholic solution of corydalina we add a little sulphuric acid, so as not to su])ersaturate the base, and then evaporate the li(piid, we obtain, in the first place, the crystallized salt. The mother water being afterwards evaj)orated to dryness, yields a translucent mass of a greenish-yellow colour, having the appear- an(;e of gum, not altered oy exposure to the air, and very soluble in water. It reddens litmus pai)er. When there is an excess of concentrated sulj)huric acid present, the base is destroyed. .TAMACINA. 289 I the ; the )ured being it as- eyisli- coliol, )lution at t\ie c crys- ^(lalina litmus, 1 does, locomcs nd this state of 212°. 5 a crys- i brown, a brown sponsion water it IS, which ho water \. Ether tter sol- colour. ,vhen wc The Idalina in an in- jhol, and digested Itrated by ]\u water, jidphuric irate the It. The yields a a^ipear- ly soluble lexcess of 3. Nitrate of corydalina. Nitric acid destroys corydalina, and grives it a red colour when the liquid is concentrated. This reac- tion is so sensible, that nitric acid, heated with a liquid containing, corydalina, detects the most minute quantity of that base. 4. Acetate of corydalina. Concentrated acetic acid dissolves corydalina much more slowly than the mineral acids. When the solution is evaporated we obtain the acetate of corydalina in crystals. This salt is very soluble in water. Corydalina is precipitated from its solutions by infusion of nut- galls, which constitutes an excellent reagent for detecting it. SECTION VI. — OF JAMACINA. This alkali was discovered in 1824, by M. Hiittenschmidt,* in the bark oi geqffroya jamaicensis ; the geoffroya inermis, or cabbage hark tree of Dr Wright. It was obtained by the following pro- cess : — Boil the bark repeatedly in alcohol of the specific gravity 0*832, and distil off the alcohol from the filtered decoctions. Dissolve the residue in water, and filter the solution. Mix it with acetate of lead as long as any precipitate falls, and throw down the excess of lead by a current of sulphuretted hydrogen gas. Filter the liquid, and add a little sulphuric acid to it. Sulphate of jamacina falls in small grains. Concentrate the residual liquid till as many of these crystals as possible are obtained. Dissolve the sulphate of jamacina in water, and digest the solution with carbonate of barytes till all the sulphuric acid is abstracted. Filter the liquid while boiling hot, and concentrate the solution till the jamacina is deposited in crystals. These crystals are four-sided tables, translucent, and lemon-yel- low. They undergo fusion at 212°, have a very bitter taste, and seem to possess purgative qualities. They dissolve readily in water, and the colour of the solution is lemon-yellow. The aqueous solution gives a yellow precipitate, with tiucture of nutgalls. Jama- cina dissolves also in alcohol. It possesses alkaline properties, as it dissolves in acids, and forms salts. The muriate, sulphate, nitrate, and phosphate, crystallize. They have a bitter taste, and a yellow colour, are solul)le in water and alcohol, and burn when sufficiently heated. The filtrate of jamacina has a yellow colour. It melts, when heated, rather under 212°. Sulphuric acid drives off the nitric. It dissolves better in water than in alcohol. Oxalate of jamacina is obtained by saturating the aqueous solu- tion of jamacina with oxalic acid. The salt is gradually deposited in crystals. The acetate of Jamacina is obtained by the process al)ove de- scribed for the preparation of jamacina. After the excess of lead * Disser. sist. Aiiiilys. (jooffroyne Jamsiiceiisis et Surinam, as cjuotcd by L. (iinelin ; Hiiiulbucli tlir CliiMiiio, ii. 908. U m\ ■ i\ V m 290 ALKALIES IMPERFECTLY EXAMINED. has been thrown down by sulphuretted hydrojren, the sohition is to be evaporated to dryness, without the addition of sulphuric acid. • The residue is to be washed with a little cold alcohol, and purified by dissolving it in water, filtering the solution, and evaporating it. Yellow bitter-tasted tables are deposited, which melt at a tempera- ture lower than 212°, and then take fire and burn, giving out the odour of acetic acid. This salt is very soluble in water, and less soluble in alcohol. SECTION VII OF SURINAMINA. This alkali was discovered in 1824, by M. Overduin, in the bark of the Geoffroya Surmamenis, another species of the same genus, which grows in Surinam, and the account of it was published at the same time.* It was discovered also by M. HUttcnschmidt, who described its mode of preparation and its properties, in his in- augural dissertation. M. Van der Byll is of opinion that Hiitten- schmidt's alkali was nothing else than sulphate of alumina. But this is not likely. To prepare surmamina, digest the bark in alcohol, and from the alcoholic solution distil ott' the spirit. Digest the remaining extract in water, and mix the solution Mith acetate of lead. Filter, and throw down the excess of lead by suljihuretted hydrogen gas. Filter again, and then evaporate the solution. A portion of the surina- mina precipitates. The rest may be obtained by digesting the liquid with magnesia, filtering, and ftirther eva])oration. Surinamina thus obtained is in bulky, woolly-looking needles. Its colour is white, its taste not strong, but disagreeable, and when given to the extent of two grains it had no effect upon a pigeon. It is but little soluble in cold, though moderately soluble in hot water. The aqueouS solution is not altered by iodine, ammonia, nitrated suboxide of mercury, nor tincture of nutgalls. In hot alcohol it is less soluble than in water. In dilute sulphu- ric acid it dissolves w^ith facility. The solution is light-red, tastes like sulphate of magnesia, and yields crystals. When surinamina is heated in a glass tube, it gives out first a smell resembling bruised plums, and at last exhales a vapour, hav- ing the smell of ammonia, and leaves a bulky charcoal. When it is^ dissolved in nitric acid the solution is at first violet, and then Berlin-blue. In 48 hours the colour vanishes, and violet-coloured fli)cks are precipitated. SECTION VIII. — OF CATHARTINA. The examination of the leaves of cassia acutifolia, or common senna, was begun by Bouillon Lagrangc,f and prosecuted still farther by Braconnot. But it was Lassaigne and FeneuUe, who in 1821 extracted from them the cathartic principle, to which they are indel^ted for their introduction into medicine.^ This principle, to * Aim. tlor Pli;inn;ioit>, vii. 205. f Ami. do Cliiiii. x;;vi. ;). X Aim. lie Cliiiii. ft de I'liys. x\i. 10. GUARANINA. 291 13 to acid, ivified njr it. ipcra- ut the id less le bark genus, I at the It, who his in- liittcn- L. But rem the extract ter, and . Filter ! surina- Ding which they give the name of cathartina, was obtained in the follow- ing manner : — the lies. Its id when pigeon. in hot mmonia, sulphu- tastes )ut first |ur, hay- IWhen it knd then coloured Icommon ll farther lin 1821 |hey are -iple, to The decoction of the dried leaves of senna was precipitated by acetate of lead, and the filtered solution treated with sulphuretted hydrogen, to throw down any excess of lead that may have been added. The liquid was now evaporated to dryness, and the residue treated with alcohol which dissolved the cathartina, together with some acetate of potash. The alcoholic solution was distilled till it was brought to the consistency of an extract and then mixed with alcohol containing some sulphuric acid, in order to throw down the potash in the state of sulphate. The liquid was now filtered to separate the sulphate of potash. The excess of sulphuric acid was thrown down by acetate of lead, and the excess of lead by sulphuretted hydrogen. Nothing now remained but the cathartina held in solution by acetic acid. By adding ammonia and evaporat- in"- to dryness it was obtained in a separate state. Cathartina thus obtained has a yellowish-red colour, and cannot be made to assume a crystalline form. Its smell is peculiar, and its taste bitter .and nauseous. It is very soluble both in water and alcohol ; but it is insoluble in ether. When exposed to the atmo- sphere it gra'-lually absorbs moisture. Its aqueous solution is pre- cipitated in brown flocks by the infusion of nutgalls. The diacetate of lead occasions a precipitate, having the same shade of colour. Sulphated peroxide of iron strikes with it a brown colour. The alkalies do not throw it down from its aqueous solution. Whether it possesses alkaline properties has not been determined ; but it is probable that it does, because in senna it seems to be in the state of a nialate, and because it combines with acetic acid. It pos- sesses the purgative qualities of senna in great perfection. SECTION IX OF GUARANINA. This substance was discovered by Theod. Mirtiua in the giiarana, a Brazilian medicine obtained by drying the fruit of the paullinia sorhilis* To prepare it mix guarana in powder with one third of its weight of slacked lime, and digest the mixture in alcohol of the specific gravity 0*852, till every thing soluble be taken up. Filter the solu- tion and distil^ off a little of the alcohol, then allow the liquid to cool in order to get rid of a greonisli fat oil which will have made its appearance. After separating this oil continue the distillation till the greatest part of the alcohol is drawn off. The residue is to be evaporated to dryness, and the dry matter remaining heated in a subliming apparatus. The guaranina which first sublimes is yellow ; but afterwards it rises in the form of white feathery crystals. Guaranina, thus obtained, is little soluble in watcn*, but very solu- ble in alcohol. Tlie solution has a bitter taste, and gives a green * KustiK.'r's Arch. vit. 'J(!(i. 292 ALKALIES IMPERFECTLY EXAMINED. colour to the tincture of rose leaves. When the alcoholic solution is evaporated the guaranina is deposited in the form of crystals. It combines by fusion with phosphorus and sulphur, the compound is brown, and, when it is digested in water, the guaranina is dis- solved. It combines also with iodine. When heated with concen- trated sulphuric acid it is partly volatilized and partly decomposed. When assisted by heat it combines with the fixed oils and with cam- phor—the combination of it with camphor crystallizes ; that with the fixed oils is partly crystalline, partly unctuous. Tlie solution of guaranina is precipitated by the infusion of nutgalls. Guaranina seems to possess alkaline properties ; but hitherto none of its salts have been examined; nor have any experiments been made to determine its atomic weight or its ultimate constituents. SECTION X. — OF HURINA. There exists in the hot valleys which surround the table land of Bagota a tree named by the natives AJuapar, which yields a yellow- coloured milk of a very acrid nature. When heated, it gives out fumes which attack the face and eyes, causing swelling, suppura- tion, and considerable pain. The ajuapar is said to be the Hum crepitans of botanists, a beautiful tree, the fruit of which is used in South America, instead of sand, for strewing upon fresh writing to prevent it from blotting. The milk of the ajua})ar was examined, in 1825, by MM. Boussingault and Rivero.* They found it to contain a volatile oil to which its acridity may be ascribed, and an alkaline principle which we may distinguish by the name of hiirina. The milk was evaporated to tiie consistence of an extract, which" was digested in alcohol of 0*837. The solution had a yellow colour, and reddened vegetable blues owing to the presence of a quantity of bimalate of potash. The alcoholic solution was evaporated, and the residu.al matter digested in water. A yellow viscid matter remained undissolved. This matter was well washed in boiling water. When digested in ether it was chiefly dissolved, but it left a small quantity of matter, which was the hurina. Hurina, when thus left by the ether, has at first the appearance of an oil. But when the ether which it contains is completely driven off it assumes the form of small crystals, soluble in water and alcohol, and having an acrid and burning taste. The solutions of it redden turmeric paper, and restore the blue colour of litmus paper reddened by an acid. These are only properties of this substance determined by Bous- singault and Rivero. They are sufficient to show that it is an alkaloid ; though none of its salts have been examined. SECTION XI OF SANGUINARINA. This substance was discovered by M. Dana in the root of the samjidnnria aivadcnsis^ which is occasionally used on the Continent as an oitictic.t » Aiiii. tic Cliini. ci ilf riiys. xxviii. JSO. f Mug-, riiiiiui. xxiii. li>j. BUXINA. 293 I solution ?stals. sompound ,na is dis- \\ concen- ;omposed. with cam- [vt with the solution of herto none nents been tituents. ible land of Is a yellow- it gives out g, suppura- »e the Hum h is used in h writing to LS examined, found it to ibed, and an \e of Imrina. tract, which" ellow colour, a (juantity of ited, and the ;ei* remained ater. When lall quantity appearance |)letely driven and alcohol, of it redden ler reddened led by Bous- that it is an le root of the Ihe Continent im . sxiii. l-J- The root is digested in absolute alcohol till every thing soluble in that liquid is taken up. Water and atnuionia being added to this solution a red precipitate falls. Wash this precij)itate and boil it with water and ivory black. Decant off" the watery portion and digest the ivory black and precipitate in alcohol, tilter and eva- porate the alcoholic solution. The sanguinarina remains under the form of a white or pearl-grey matter. Its taste is bitter. It is in- soluble in water, but dissolves in alcohol and ether ; and possesses well-marked alkaline characters. It reddens turmeric paper, and with the acids forms red-coloured salts. SECTION XII. — OF VIOLINA It has been ascertained that several species of viola contain eme- tina. But Boullay is of opinion that the viola oderata contains a peculiar alkaline principle, analagous to emetina, to which he has given the name of violina. To obtain this principle the alcoholic extract of the plant is treated with ether to dissolve some ftitty matter and some chlorophylle. The residue is to be boiled with dilute sulphuric acid, and the solu- tion is to be precipitated by hydrate of lead. The precipitate, con- sisting of sulphate of lend and violina, is to be dried and treated with alcohol. When this alcoholic solution is evaporated, the violina is left under the form of a pale yellow-coloured matter, which is to be washed with strong alcohol to deprive it of its colour. According to lioullay, violina differs from emetina by giving a green colour to reddened litmus paper, while emetina renders it blue. It is more soluble in water and less soluble in alcohol than emetina. Ether and the oils do not dissolve it. Infusion of nut- galls throws it down. Like emetina it acts as an emetic. SECTION XIII. — OF ESENBEKINA. This alkaline principle has been detected by Buchner in the Esenhekia fehrifuga.* The bark of this plant is boiled with acidu- lated water. The boiling hot solution is treated with magnesia, the precipitate is dried and digested in boiling alcohol till every thing soluble is taken up. When the alcoholic decoction is evaporated, the esenbekina remains in a mass, having a pigeon's-neck lustre. It has a bitter taste like that of cinchona. It is slightly soluble in water, but is precipitated by oxalate of potash, infusion of nut- galls, or one of its own salts. When heated in a retort it gives out much ammonia. SECTION XIV OP BUXINA. Faure informs us that he obtained from the Imocus sempervirens an * Unless this be the Evolia febrifutja, a tree which grosvs in Brazil, and which hears a close affiiiitv to the Cinchona, I do not know what it is. The only s|)ccies iA' Esenhekia wliicli I have seen dcserihcd is stated to lie very closely allied to tviilin, and is, like it, ;k i.iitivc ot Brazil, ri\ m- u ill!: A' f ■ I 294 ALKALIES IMPERFECTLY EXAMINED. alkaline principle, to which he hao given the name of buxina* His process was as follows : — The hark of the box tree was digested in alcohol till every thing soluble was taken up. Evaporate the liquid and dissolve the resi- due in water, and boil the solution with ammonia. The precipitate, thus obtained, is digested in alcohol, which, being evaporated, leaves the buxina in the state of a dark-brown transluced mass. It is difficult to render buxina white, even when treated with ani- mal charcoal. It has a bitter taste and excites sneezing. It is in- soluble in water, soluble in alcohol, and slightly so in ether. It restores the blue colour of reddened litmus paper, and forms neutral salts with the acids which have a more bitter taste than the buxina itself. The alkalies throw down from these salts white gelatinous precipitates. The sulphate of buxina crystallizes confusedly. M. Couerbe has succeeded in obtaining buxina in crystals. His process was to add nitric arid to the sulphate of buxina. This acid removes a resinous matter aud leaves sulphate of buxina pure. From the salt thus purified pure buxina may be precipitated in crystals.f SECTION XV OF EUPATORINA. This alkali is said to have been discovered by M. Righini in the flowers and leaves of the Eupatorium cannabinum, or hemp agrimony, a plant indigenous in Great B.itain4 He boiled, for 2 hours, 2 lbs. of the leaves in 10 lbs. of water acidulated with half an ounce of sulphuric acid. This process was repeated. The two decoctions were mixed and saturated with lime. The precipitate obtained was exposed to the air to favour the action of sulphuric acid on tlie lime. It was then digested in 8 lbs. of alcohol of 0*817, during two days, in a temperature between 113° and 122°. The filtered liquor was then distilled to sepai'ate the alcohol. The residue evaporated in a porcelain basin yield the eupatorina. It is under the form of a white powder, having a pecu- liar taste analagous to that of the bitter principle contained in eupatoria ; but at the same time sharj). It is insoluble in water, but soluble in ether and alcohol. When lieated it swells up and burns. It combines with sulphuric acid, and forms a sulphate which crystallizes in silky needles. Such are the characters given by Righini. But they are insuffi- cient to distinguish it from other alkaloids. Nor have we any evi- dence that it was obtained in a state of purity. SECTION XVI. — OF CRYSTALLINA. When indigo is subjected to dry distillation, we obtain first water, and an oil, and afterwards resin, mixed with oil, comes over. The oil obtained by this jjrooess has been particularly examined by Unverdorbcn.§ It has ii peculiar, but not disagreeable odour. Part oft his oil * .I'Hir. (le riiariiMcic, wi. l-'J*'^. f litiii. \x. fy\. § I'ofjfgotitlorfs Aniialpn, viii. ;J07. Uiiii, xiv.fJ-23. tvipa TIIEINA. 295 ar His ery thing the resi- •ecipitate, ed, leaves I with ani- It is ii»- cther. It ms neutral the buxina irelatinous A'. stals. His This acul uve. From crystals-t [crhini in the ,p agrimony, lbs. of water 1 process was turated with air to favour digested in B ture between ^ to separate asin yield the iving a pecu- contained in ible in water, Iwells up and IS a sulphate ley are insuffi- >e we any evi- Lin first water, ^s over. The examined by [art oft his oil li'\(i, xiv. (J-3. constitutes an oily alkaline body, wliicli Uuverdorben distinguished by the nanie of crystallina, because it has the property of forming; crystallizablt! salts with acids. It is extracted fro he emi)yreu- matic oil of indij^o by uieans of sulphuric acid, which combines with it, and enables us to distil over the remaining ingredients of the einpyreumatic oil. We have only to mix the sulphate of crystal- lina thus obtained with another base, and distil ; the crystallina passes over into the receiver. Thus obtained, crystallina is a colourless oil, which falls to the bottom of water. It has a peculiar and strong odour, somewhat resembling that of honey. It is very little soluble in water, but may be easily distilled over with that liquid. It does not restore the blue colour of litmus paper reddened by acids. When exposed to the air it becomes red. It is then soluble in water, communicat- ing a yellow colour to that licpiid. Sulphate of crystallina, whether neutral, or containing an excess of acid, crystallizes. When the neutral salt is evajjorated, it gives out crystallina, and passes to the state of a bisalt. It is insoluble in absolute alcohol. Its aqueous solution becomes gradually brown, and then contains suli)hate of fuscin in solution. When the bisul- ])hiite is heated it melts, and, on cooling, concretes into a crystal- line mass. When heated more strongly it is decomposed, sulphate of crystallina, sulphate of oderuia, and a great deal of sulphate of ammonia being formed. Phosphate of crystallina crystallizes easily when neutral, but the bisalt does not crystallize at all. Alcohol separates crystals by re- moving the excess of acid. The other salts of this base have not been examined.* SECTION XVII. — OF THEINA. Oudry has lately announced that he has discovered in tea a sali- fiable basis, to which he has given the name of theina. I'o obtain it, let 12^ parts of tea be infused in 200 parts of water, holding in solution 3 parts of common salt. After 24 hours' infusion evaporate the liquid to dryness, and treat the dry residue with alcohol of the specific gravity 0*8 1. Evaporate the alcoholic solution, dissolve the residue in water, and digest the solution with magnesia. The li(|uor, filtered and evaporated to a certain degree of concentration, deposits "vystals of theina. The magnesia, when digested in al- cohol, givos up an additional quantity of theina to that liquid. Theina at the temperature of 50°, requires from 3.5 to 40 times its weight of water to dissolve it. From that solution it may be ob- tained in fine prismatic needles. It dissolves in all proportions in alcohol, but that solution yields only ill-defined crystals. When theina is heated it melts, and at a still higher temperature under- goes decomposition, leaving a residue of charcoal. Oudry assures us that thehia combines with sulphuric acid, and ^that the salt is raj)able of crystallizing.t * Soc l'()gfreminrr'.« Aniialcn, viii. 39". t Nouvcllc I^ibl. Med., March 18-J7, and Mnpr. riiarni, xix. 49. 290 METHOD OF DETECTING THE VEGETABLE ALKALOIDS. APPENDIX. METHOD OF DETECTING THE VEGETAULE ALKALOIDS. The greater number of these alkaloids being poisonous, it comes to be an object of importance to be able to discover their presence, when they have been employed in order to destroy life. I -shall, therefore, in this place, state the tests which have been discovered to obtain this object. So far as we know at present, all the alkaloids are precipi- tated by tannin. The first step, therefore, when we examine a liquid, to discover whether it contains any of these bodies, is to droj) into it a little of the fresh infusion of nutgalls. If an alkaloid be present, a bulky white precipitate will fall. Wash it with cold water. Tiien mix it intimately with a slight excess of slacked lime. Dry the mixture over the water-bath. Digest it in alcohol. Put the alcohol in a watch glass, and leave it to spontneous evapora- tion. The alkaloid will crystallize.* Morphina and strychnina crystallize in pris-iiis; cinchonina in arbori.'^ed needles ; brucina in ramified plates ; quinina does not crystallize at all, but its acetate crystallizes in beautiful feathers.f I. ALKALOIDS IN OPIU.^I. The alkaloids known to exist in opium are six in number, namely, thebaina, narcotina, codeina, morjjliina, meconin and narceina. These substances when in a solid ant' separate state, may be dis- tinguished by agitating a few grains of each in half an ounce of sul- phuric acid, containing some nitric acid mixed with it.J 1 . Thebaina instantly reddens, and the shade becomes gradually deeper. When viewed in a thin layer it has a yellowish aspect. 2. Narcotina becomes first yellow. It retains that colour for seven or eight minutes, and then becomes red. Even suits contain- ing nitric acid produce this effect, according to the observation of M. Louis Mialhe de Vabre.§ 3. Codeina assumes at first a weak green colour, which passes after some time to bluish-green. 4. Morphina instantly assumes a green colour. 5. Meconin is at first unaltered, but after 24 hours it assumes a fine rose-red colour. (i. Narceina assumes immediately a yellowish-red colour. It was observed by Dr Meeson, in 1835,|| that if a solution of morphina, or any of its salts, be mixed with a strong solution of chlorine, and ammonia be added, a d' .A-l>rown colour pervades the solution, which will disappear by the addition of more chlorine. * O. Henry, Jour, tin I'liiirmacic. xxi. 22. f Donin', Ibid. xvi. ;J74. I Couerbi', Jour, dc I'harniacic, xxii. 84. § llikl. ji. 086. li rhil. }>hvr. (Third Scries), vi. 108. STIIYCHNINA, HllUClNA, VEUAII A. f»r imes to esencey I-slmll, jovereil precipi- imino a >s, is to alkaloid ith colli cd lime. .1. I'ut jvapora- anina in iloes not itbers.t namely, larceina. be dis- te of sul- radually ject. dour for contain- vation of j\ passes bsumes a lution of iution of ides the tine. i. ;n4. Andre, in 1836, foinul that when a little linnid chlorine is added to a weak a(|ucou8 solution oimorphino, or any of its salts, the; liquid be- comes yellow, with a slight orange tint. Ammonia renders the coloui more intense. An acid weakens, but does not destroy this colour.* When solutions of narcotina are treated in the same way, no colour is produced."!- When iodic acid, or an acid iodatc, is dropt into a solution of morphina, or a salt of morphina, the liipiid innnediately assumes a red colour.^ The acid is decomposed by the morphina, and the iodine disengaged. Perchloride of iron gives a deep-blue colour to morphina. Morphina is precipitated from its solution in nitric acid by proto- chloride of tin of a dirty-broicn colour. When we wish to discover the presence of morphina in the con- tents of the stomach, or in sugared water, broth, milk, cotlee, beer, &c., we must proceed in th*^ following way : — Let the liquid be acidulated by means of acetic acid, and let it be concentrated to the thickness of a syrup. Drop into it a little am- monia. A precipitate will fall, which must be collected on a filter, washed, and dried. It is pure morphina, which may be recognised by the characters given above. Should ammonia throw down no precipitate, which is apt to happen, especially when the morphina is dissolved in beer, we nmst, after having reduced the liquid to the consistence of a syrup, digest it in alcohol, and then precipitate the alcoholic solution by means of ammonia.§ M. Lassaigne has proposed a method nearly the same as the pre- for detecting the presence of acetate of morphina in the contents of the stomach of animals poisoned by that substance. He filters the liquids contained in the stomach, evaporates them cau- tiously, and then digests the residue in boiling alcohol of 0*837, which separates the animal matter present. The alcohol is evapo- rated to the consistence of an extract, and treated by distilled water to separate any fatty matter that may be present. The liquid is then filtered, and evaporated slowly. Crystals of acetate of mor- phina gradually form, which may be detected by their characters. |1 The method of detecting morphina which has succeeded best with me, is to precipitate it by fresh made tincture of nutgalls. Alcohol dissolves the tannate of morphina. By the solution of isinglass the tannin may be separated from the morphina, and this latter sub- stance obtained dissolved in alcohol. By evaporating the alcoholic solution, we obtain the morphina in a separate state, and can easily ascertain it by its characters. II. STUYCHNINA, BRUCINA, VERATRINA. Strychnina, when treated with sulphuric acid, assumes a yellow colour, passing into brown.^ * Aiuln'', Jour, dc Pliiirmacic, xxii. 134. +AiKlri', Ibid. t Serullas, Jour, df I'liann. xvi. '200. § Ibid, xviii. oi- U Ibid. x. 'iOfi. % Ibid, xviii, 4H. ceding. ' ^Jl m.\ 298 MF.TIIOI) or DKTKCTINO THE VIUJETA ril.K .M kAI.Oin*. When tilt! •ilc()Iu>li(r solution of hnirina i.s put in o'liitiuf with bruniine, it uiv»;.s, after hoiiio tiino, a tino vioh't colour. Verotrinn, when treutod with sulphuric aciil, m^ivos a lieuutiful violet eolour.* When chlorine is mixed with a Holution of strychnina, that Bolution becomes milky. Tlu! addition of aunnonia determines i\ precipitate, which gnidually disappears, and tho liquid remains niilky.f Bnicinn, when treated with chlorine, gives the same results us strychnina. Hut when treated with protochloride of tin, it j^nves a violet precipitate. Nitric acid tinjjes hrucina yellow. Iodic acid producer no sensible change upon solution of brucina und strychnina. Strychnina, brucina, and veratrina, have the pro])erty of forming insoluble salts with muriatic acid. Advantage has been taken of this property to discover their presence in solutions. Evaporate the solutions containing them to the consistence of a syrujt, then mix with the Tupiid a little muriatic acid and corrosive sublimate. A copious white precipitate falls, which being redissolved, and treated with sulphurct of barium and sulphuric acid, leaves a solu- tion of the alkaloid j)resent easily recognised by its properties.^ When strychnina conies in contact with the vapour of iodine it becomes fine yellow, and brucina and veratrina become a dirty- yellow. The vapour of bromine clianges veratrina and strychnina to yellow. It changes brucina to greenish-yellow. § When strychnina is treated with sulphocyanate of potash, it be- comes muddy, and deposits beautiful crystals in fine white s^ars. If we heat the licpiid to 158° the crystals dissolve, but apjiear again in silky needles when tlm licpiid cools to (33°^. In this way strychnina may be detected in a solution containing only 77 jth of its weight of that alkaloid. When we mix corrosive sublimate with a solution of strychnina, and throw down the mercury by sulphuretted hydrogen, muriate of strychnina remains in solution, and may be recognised by its properties.il III. QUININA, CINCnONINA. When a little liquid chlorine is added to a dilute aqueous solution of quinina, or salt of quinina (except the sulphate), the solution be- comes slightly brown. This ft'ect will not be sensible if the licjuid con- tain an excess of acid. The chlorine first seizes upon the ammonia united to the resin of (|uinina, obliging it to remain in suspension for want of a solvent. The li(iuid becomess lightly blue ; but on adding an excess of chlorine the resin is dissolved, and the colour tlisappears or becomes yellow. Ammonia throws down a green precipitate, which instantly redissolves, communicating a fine ' AihIm', Jour (Ic Pharni. xxii. l.'Ji. f Andre, Ibid. X Jouniiil lie riiariiiacie, xviii. ,j;j. sj Ibid. xvi. a7.i. !| Artus .lourn. fiir prari. Cb. iii. y-JO. SAi.iciy. '2<»!> with uitit'ul , tluit inos a LMUuinrt ults art rives a brucina forminsJj aken t)f aporatc H», then hlimate. ed, ami s a 8olu- ics.t iodine it a dirty- rychnina ih, it he- s^ars. If aj^ain in rychnina .eight of lution of ydroficn, bcogniscd s solution lution be- Jiquid eon- ammonia tuspcnsion but on fhe colour a green tine emcrald-ji:reon oolour.* If the solution of quiitina thu.s treated he coneentriited, the iifi fen is tlull. If we very (•iiiitiously ueutrali/e the nminoniu, the li(|uid assuuies a sky-litue colour. If too nntch ai'in sponay platinum is introduced, the action goes on with uuconnnon rapidity. If we lot fall a drop of it into a vessel IL-. ALDEIIYDK. 303 iwliicli jair, it trated ^oes full of moist air, wo iinincdiately pcM'ceive a strong smell of acetic acid. Aldehyde dissolves sulphur, phosphorus, and iodine ; but these bodies do not appear to unuergo any alteration. Chlorine and bromine are absorbed with the evolution of much heat, while muria- tic and hydrobromic acids are produced. Liebig is of opinion that in these reactions the aldehyde is changed into chloral and bromal. Weak nitric acid, when heated with aldehyde, decomposes it, nitrous acid being disengaged, and acetic acid formed. Concentrated sulphuric acid when mixed with it becomes immediately deep-brown, and afterwards black and thick. When liydrated aldehyde is heated with potash, the liquid becomes first yellowish and muddy. In a short time a brownish-red resinous matter separates and swims on the surface. To this matter Liebig has given the name of aldehyde resin. If we heat aldehyde with water and oxide of silver at first moder- ately, and then raise the liquid to the boiling temperature in a glass tube, the silver is revived, and covers the glass with a brilliant coating, like a mirror ; showing that no iras is evolved during this process. After this reduction we have lu the liquid a Siilt of silver, and the liquid may be evaporated without any farther reduction of the silver to the metallic state. If we add to this liquid, after allowing it to cool, as much barytes water as is requisite to throw down all the oxide of silver, and if we now heat the liquid without removing the precipitated oxide, the whole silver is reduced to the metallic state without the evolution of any gas. If we mix the liquid with nitrate of silver, immediately a great number of plates of acetate of silver aro deposited, and no other product is observed but acetic acid. Thus it apjjcars, that when the salt of barytes is boiled with oxide of silver, the acid in combination with the barytes, is converted into acetic acid by the absorption of oxygen. The very same phenomena are observed when aqueous aldehyde, to which a few drops of ammonia have been added, is heated with oxide of silver. The reduction of oxide of silver which takes place in this experiment affords an easy method of ascertaining the ])rcsence of the smallest quantity of aldehyde in any liquid in which it may be suspected. When aldehyde is kept in vessels to which air has access, oxygen is absorbed, and a number of prismatic crystals are formed. Those crystals fuse when heated to 212°, and when raised to a higher temjjerature, sublime in splendent transparent white needles. They are hard, easily pulverised, inflammable, without smell, soluble in alcohol and ether, but not in water. Besides these crystals, there is a liquid which makes its appearance in the aldehyde, very similar to acetal in its characters. Liebig analyzed aldehyde in the usual way, by heating it with oxide of copper. Its great volatility renders the process difficult. The result was as follows : — 304 ALCOHOL AND ITS COMPOUNDS. h < 8 ' ;i;in Carbon 53-67 or 4 atoms = 3*0 Hydrogen 8*97 or 4 atoms = 0'5 Oxygen 37'3(i or 2 atoms = 2 or per cent. 54-55 9-09 30-36 100-00 5-5 100-00 M. Liebig determined the density of the vapour of aldehyde, and found it 1-532. Now, if we consider vapour of aldehyde as composed of 4 volumes carbon vapour, 4 volumes hydrogen gas, and 1 volume oxygen gas, condensed into 2 volumes, we have 4 volumes carbon vapour . = l-6()66 4 volumes hydrogen gas . = 0-2777 1 volume oxygen gas . =1-1111 2)2^9555 1-4777 =sp. gravity of aldehyde vapour. The vapour then is composed of 4 volumes carbon, 4 volumes hydrogen, and 1 volume oxygen, condensed into 2 volumes. Now that the composition of aldehyde is known, it is easy to see how, by means of oxygen, it is converted with such fiicility into acetic acid. Acetic acid . . . C* H^ 0» Aldehyde . . . . GUI* O^ If therefore the oxygen combine with one of the atoms of hydrogen, and convert it into water, while another atom of oxygen replaces the hydrogen, it is obvious that aldehyde will become acetic acid. Liebig is of opinion that there exists an unknown basis composed of C* H^ to which he has given the name of aldehyden. The oxide of this basis is C* IP O, and when this oxide is combined with an atom of water it constitutes aldehyde, the true formula for which is C* H3 O + HO. Acetic acid is C* IP 0» + HO. It is obvious also that alcohol and aldehyde differ from each other merely by the aldehyde containing 2 atoms less hydrogen than alcohol. Alcohol is . . . C H« O^ Aldehyde ... C* H^ O^ Ammonialdehyde. The preparation of this salt has been already described. The crystals are acute rhomboids, the faces of which meet at an angle of about 85°. They are colourless, transparent, and refract the light strongly. Thoy have the hardness of loaf sugar and are easily reduced to powder. They have a smell both of ammonia and turpentine. They are volatile, melt when heated to between 158° and 176°; probably aboat 167°, and they may be distilled un.altered at the temperature of 212°. Their vapour reddens turmeric paper, and their aqueous solution acts as an alkali. The acids, even the acetic, decompose this salt. An ammoniacal salt is formed, and aldehyde is set at liberty. It is exceedingly solu- ble in water, a little los* so in alcohol, and with difficulty in other. ALDEHYDE. 305 5 9 6 de, and krolutncs oxygen ). gravity volumes ised into Lsy to see ility into liydrogen, places the cid. composed ;he oxide Id with an which is lach other Ijjen than ah-eady of which |nsparcnt, 5S of loaf hi both of licated to may he reddens Hi. The :a\ salt is |irly solu- liii other. When exposed to the air and light the crystals become yellow, and acquire an odour resembling burning animal substances. If these crystals, after they have become brown, be distilled over the water- bath, ammonialdehyde sublimes in its usual state of purity, and there remains a brown resin, insoluble in water, which contains acetate of ammonia, and another ammoniacal salt. We obtain crystals of ammonialdehyde of uncommon size and beauty if we mix ether with a concentrated alcoholic solution of the salt, and allow the mixture to remain in a state of rest. This compound behaves to acids and alkalies as aldehyde does. When we heat it with water and oxide of silver, aldehyde and am- monia are disengaged ; a portion of the oxide of silver is reduced, and the other phenomena take place which have been already described. This salt was subjected to analysis by Liebig, by means of oxide of copper. He obtained the following results : — Carbon 39*8 or 4 atoms = 3 or per cent. 39*34 Hydrogen 11*4 or 7 atoms = 0-875 — — 11*47 Azote 23-0 or 1 atom = 1-75 — — 22-96 Oxygen 25-8 or 2 atoms = 2-00 — — 26*23 100-0 7-625 100-00 These atomic numbers may be resolved into 1 atom aldehyde . C* H* O* 1 atom ammonia . H' Az C* W 02 Az If we mix together concentrated solutions of ammonia, aldehyde, and nitrate of silver, a white, brilliant, granular precipitate falls, readily soluble in water, but with difficulty in alcohol. It may, therefore, be obtained pure by washing it with spirit of wine. If the solution of this precipitate be gently heated, aldehyde is disengaged, and a portion of the oxide of silver reduced. If we heat the solu- tion with concentrated sulphuric acid, nitrous acid is disengaged, and if we mix it with lime there is a disengagement of ammonia. Hence it appears that the precipitate contains aldehyde, ammonia, nitric acid, and oxide of silver. Licbig's attempt to analyze it did not succeed. But it is obviously a combination of ammonialdehyde and nitrate of silver, in proportions not yet determined. Aldehyde resin. It has been already observed, that when an aque- ous solution of aldehyde is heated in contact with a solution of potash, the liquid becomes muddy and yellowish, and speedily a soft brownish-rod matter comes to the surface, having a spirituous, but disagreeable smell, and so adhesive that it may be drawn out into threads. This matter is produced when potash is dissolved in alcohol, and most speedily when the access of air is permitted. It is to the presence of this substance that the alcoholic solution of potash owes its reddish-brown colour. It is produced also in a few minutes when a solution of potash in alcohol and acetal is exposed X f h %\ m m 306 ALCOHOL AND ITS COMPOUNDS. hi VI ''\ 1 1 1 ■ i . 'f. I ( • ■ f i r I \ _ to the air. This is a useful character to enable us to distinguish acetal from acetic ether and other etherial liquids. All the liquids containing aldehyde, nitric ether, muriatic ether, &c., assume a reddish-brown colour when heated with potash ; and when diluted with water, or an acid, the resin of aldehyde separates in brown flocks. If the liquid obtained by distilling a mixture of spirit of wine, binoxide of manganese, and sulphuric acid, be heated to the boiling temperature, and then mixed with water, an abundant precipitate of resin of aldehyde is obtained. When this substance is boiled in water it collects into lumps, becomes of a deep-brown, almost black colour, and when pounded gives a light-brown powder. This powder, when washed in water, forms a deep brown -coloured so- lution. If we dry this substance first at the ordinary temperature of the atmosphere, and then at the temperature of boiling water, we observe a peculiar spirituous smell, and it sometimes takes tire of its own accord at that temperature, and burns like tinder. When heated in a spoon it burns like resin, leaving a brilliant charcoal, difficidt to incinerate. It was analyzed by Liebig, and its constituents were found : Carbon 73*3405 or 5 atoms = 3*75 or per cent. 73*17 Hydrogen 7*7590 or 3 atoms = 0-375 — — 7-31 Oxygen 18*9005 or 1 atom = 1*00 ~ _ 19*52 100*00 100*0000 5*125 But the analysis is scarcelv entitled to confidence. Aldehydic acid. It has been shown that when aldehyde is made to act upon oxide of silver, a portion of the silver is reduced, and that an acid is formed which combines with another portion of the oxide of silver, and forms a salt, decomposable by barytes, and that then the acid is easily converted into acetic acid. Liebig has given to this acid the name of aldehydic acid* The action of this acid on the oxides of mercury and silver, and on the salts of these oxides, enables us to distinguish it from all other acids. W'hen mixed with nitrate of silver, the liquid becomes muddy ; when heated it assumes a blue colour, and the glass becomes covered with metallic silver. The same phenomena appear when the acid is mixed with solutions of gold or platinum. Oxide of silver dissolves in this acid ; but when the solution is heated the silver is reduced. Nitrate of mercury, heated with this acid, is immediately decomposed. A kind of metallic shower falls, and brilliant globules of mercury collect at the bottom of the vessel. The red oxide of mercury dissolves in the acid. When heated a * He considers it as the lampic acid of Daniell. But Mr Connel has shown thut lampic Hcitl is a mixture of about 3 parts of formic acid, and 1 part of acetic acid.— See Phil. Mag. (Third Series), xi. 512. COaiPOUNDS OF ALDEHYDEN. 307 stinguisli lie liquids assume a n dilutctl in brown t of wine, lie boilins cipitatc of boiled iu most black er. This loured so- turc of the we observe of its own n heated in difficult to tuents were 73-17 7-31 19-52 100-00 vde is made educed, and irtion of the s, and that Ig has given silver, and )ra all other |ies muddy ; les covered 3n the acid solution is Ll with this liower falls, I the vessel. [n heated a ijl has shown [part of acetic white salt in micacious crystals is formed, and metallic mercury separates at the same time. When this acid is neutralized by barytes, a salt is formed, which is not easily crystallized, and which deliquesces in moist air. It acts upon the salts of mercury and silver in the same way as the free acid. When the salt formed by the combination of this acid with oxide of copper is heated, the copper is reduced. Aldehydic acid is de- composed by sulphuric acid with the deposition of charcoal. Liel)ig has ascertained that when oxide of silver is heated with aWehyde, one half of the oxide is reduced to the metallic state, while the aldehyde becomes aldehydic acid. Hence it is obvious that an atom of aldehyde, to be converted into aldehydic acid, re- quires to c. bine with one atom of oxygen. Hence aldehydic acid is composed of C* H* 03 It differs from acetic acid merely by containing an additional atom of hydrogen. Hence the facility with which it is converted into acetic acid by the action of oxide of silver. SECTION II OF COMPOUNDS OF ALDEHYDEN. It has been already stated that Liebig conceives that there exists an unknown base composed of C* H', of which aldehyde constitutes a hydratcd oxide. M. Regnault has rendered this opinion exceed- ingly probable, by discovering compounds of this unknown base with chlorine, bromine, and iodine. The two last of these we shall here describe. 1. Bromide of aldehyden. If we mix together an alcoholic solu- tion of bromide of deutocarbohydrogen (plefiant gas), with a con- centrated alcoholic solution of potash, a white precipitate falls, and the liquid begins to boil, giving out a peculiar smell. If we keep th? mixture in a temperature between 86° and 100° an ethereal gas, with the smell of garlic, is disengaged. To this substance Reg- nault has given the name of bromide of aldehyden. To render it pure it may be passed through a little water, and then through a long tube filled with chloride of calcium. When exposed to a freez- ing mixture of snow and salt, it is converted into a thick liquid. In this state it was mixed with oxide of copper, and analyzed by Reg- nault, who obtained Carbon 22-17 or 4 atoms =3 or per cent. 22-43 Hydrogen 2-92 or 3 atoms = 0'3;ii — — 2-80 Bromine 74-91 or 1 atom =10 — — 74-77 100-00* 13-375 100 Regnault determined the specific gravity of this bromide in the state of vapour, and found it 3-69 1 . Now * Ann. der Pharni, xv. G^. ii fill.' b I I i m m mi { 1 1.1:1 i _f 308 ALCOHOL AND ITS COMPOUNDS. 4 volumes carbon vapour weigh 3 — liydrogen — 1 volume bromine — 0-2083 5-5400 2)7-4150 3-7075 It is therefore composed of 4 volumes of carbon vapour, 3 volumes of hydrogen gas, and 1 volume of bromine vapour, united together, and condensed into 2 volumes, or to a fourth part of the original bulk, before combination. Bromide of aldehyden, in a liquid state, is a colourless and very volatile fluid. Its specific gravity is 1-52. Its smell resembles that of garlic, but is not disagreeable. It boils at the common tempera- ture of the atmosphere, and when in the state of gas is absorbed in considerable quantity by water. Chlorine decomposes it, and converts it into the chloride of olefiant gas. Bromine decomposes it also. A portion of liquid bromide of aldehyden was mixed with bromine, and exposed in a close glass balloon to the solar light for several days. On opening the vessel a quantity of acid vapour, probably hydrohromic acid, escaped. When the liquid remaining was washed with alkaline water, an etherial liquid fell to the bottom, which was heavier than sulphuric acid. It boiled at a tem- perature above 212°, and had a perfect resemblance to bromide of bicarbohydrogen. Regnault considers it as identical with this bromide, though he did not succeed in making a satisfactory ana- lysis of it. Neither hydrohromic nor muriatic acid decompose bromide of aldehyden. Potassium slowly decomposes it, being converted into bromide of potassium. The decomposition goes on much more rapidly when heat is applied. The potassium becomes red-hot, and charcoal is disengaged. But no C* H' is evolved. When bromide of aldehyden is passed through a hot tube contain- ing metallic iron, charcoal is always deposited, and a gas is disen- gaged, which seems to be a carbohydrogen. When the tube was of an incipient red heat, the gas evolved was a compound of 110 vo- lumes hydrogen, and 45 carbon, and a strong smell of naphthaline was perceptible. 2. Iodide of aldehyden* When a concentrated solution of caustic alkali is poured upon iodide of bicarbohydrogen, a lively action is produced, and a gas is evolved, having the smell of garlic, similar to that given out by chloride and bromide of bicarbohydrogen under like circumstances. After some time the decomposition ceases, and can only be completed when the mixture is heated to between 122o and 140°. This gas may be purified by passing it through a little water, and then through a long tube filled with chloride of calcium. When exposed to a freezing mixture of snow and salt, it is converted I Regnault, Ann. der Pliurm. xv. 69. Hi ACETAL. 309 into a liquid, which afterwards continues in that state, even at the usual temperature of the atmosnhore. A portion, however, retains the gaseous state, and still smells feebly of garlic. This gas, from tliJ analysis of Regnault, appeared to be bicarbohydrogen. The liquid portion was the iodide of aldehyden, h-id a specific gravity, when in a state of vapour, of 4'76. Now, 4 volumt . i^cirbon weiffh . I'GOGG weigh 3 — hydrogen — 1 volume iodine — 0-2083 8'8 2)10-0750 5-3375 We see from this that, like bromide of aldehyden, it is composed of 4 volumes carbon, 3 volumes hydrogen, and 1 volume of iodine va- pours, condensed into 2 volumes. SECTION III. OF ACETAL. This substance was discovered by Dobereiner, but examined and named by M. Liebig, in 1833.* Dobereiner's process was the fol- lowing : — Alcohol of the specific gravity 0-8631 was put upon a saucer; a support was placed in the saucer, the top of which is raised a few lines above the alcohol ; and upon this support a number of watch glasses are arranged, having a quantity of spongy platinum in each. The whole is covered by a bell glass, open above, so that the walls of the glass are in the saucer containing the alcohol, in order that the vapours which condense upon them may tumble back into the alcohol. The apparatus thus disposed is left in a place not too cool till the alcohol acquires a very acid taste. The whole is then distilled over carbonate of lime. To the product of this distilla- tion chloride of calcium in powder is added. This causes the sepa- ration of an ethevial liquor, to which Liebig has given the name of acetal. It is colourless, as fluid as ether, and has a smell, which Dobe- reiner refers to that of nitric ether — Liebijj to that of muriatic eth^r. Its specific gravity is 0-823. It boils at 203°. It may be mi^.ed with a'cohol and ether in any proportion. Watar dissolves the sixth part of its weight of it. It burns with a bright flame. When the action of spongy platinum is prolonged, the acetal is con- verted into acetic acid. The addition of potash changes it into a brown resin, and sulphuric acid produces this change still more rapidly. But Liebig has shown that this resinous matter is not formed when the acetal is pure. It was analyzed by Liebig, who obtained * Ann. ilcr I'liannucie, v. 2,j. l m 'iIt ^^llh I i i I 310 Carbon Hydrogen Oxygen ALCOHOL AND ITS COMPOUNDS. 58*72 or 8 atoms = 6 or per cent. 59*2(5 11*35 or 9 atoms = 1*125 — — 11*11 29*93 or 3 atoms = 3 — — 29*()3 100*00 10*125 100*00 If we compare this formula with that which gives the constitution of alcohol, it will bo obvious that the action of the spongy j)latinum consists in the combination of the oxygen of the atmosphere with part of the hydrogen of the alcohol — 2 atoms alcohol 0« H'» O* Take away 2 atoms hydrogen, 1 atom water H ' O Remain C* II " O or acetal. We might also consider acetal as a compound of 1 atom acetic acid C * H 3 O' 3 atoms ether . . C'^ H'^ O^ C" H'» 0« For it is obvious that C" H'» 0« is a multiple of C» H'-' O^ Or, what is still simpler, we may consider it as C* H* + H* O'^ and then it would come under the second set of compounds men- tioned in the next Chapter, as incorrectly called ethers. SECTION IV. — OF DEUTOCARBOHYDROGEN. Olefiant gas, which I distinguish by this name, has been described at sufficient length in the Chemistry of Inorganic Bodies. But se- veral compounds of it, which have been lately formed, or more accu- rately examined, require to be noticed here : — 1 . Chloride of deutocarbohydroffen, or oil of the Dutch chemists. This substance, rendered as pure as possible, was analyzed by Reg- nault, who obtained Carbon 24*02 or 2 atoms =1*5 or per cent. 24 Hydrogen 4*04 or 2 atoms = 0*25 — — 4 Chlorine 72*38 or 1 atom = 4*5 _ _ 72 100 100*44* 0*25 This analysis corresponds with tliat of Dumas. The specific gravity of the oily liquid was 1*256. Regnault found the boiling point 180°*5. The specific gravity of its vapour was 3*45. 2 volumes carbon weigh . 2 — hydrogen — 1 volume chlorine gas — Now, 0*8333 0*1388 2*5000 3*4722 Hence it is obviously composed of 2 volumes carbon, 2 volumes hy- drogen, and 1 volume chlorine gas, condensed into 1 volume. * Ann, dcr Pharmacic, xiv. -JL'. l)EUTOCAUU()HYI)RO\ ■ 1 n > «l !i ■ li (• *. I i-ii 312 ALCOHOL AND ITS COMPOUNns. 3. Iodide qf deutocarhohydmfrn. Wlion olofinnt gns is nnsscil into a ^-Inss balloon with ii lon<; nock, in the bottom of which iodine lies, and which is heated to between 122° and 140°, the iodine soon i'nses, assumes a brown colour, and yelh)w needle-aiiapcd crystals arc depo- sited in the neck of the jjlass. These, if the current of oleliant j^as bo continued, become quite white. They must be treated witii a solution of potasli or anunonia, then washed in pure water, and finally dried in vacuo over suli)huric acid. W'luni dry it is yellowisli, but may be obtained white when triturjxted with mercury, and then exposed to a stream of dry air, at a temperature between 1 13° and 122°. Iodide of deutocarbohydroj^en thus prepared has a silky lustre, and a smell which excites headach, and occasions a flow of tears. It undergoes spcmtaneous decomposition, even if kept in the dark. It melts at l()3o^. In a scnewhat higher temperature (but on the water-bath) it becomes brow n, and is completely decomposed. It is insoluble in water, but solnbL in alcohol, though in smaller quantity than the chloride and bromide of deutocarbohydrogen. It wjus analyzed by M. Hegnault, who obt; .ned Carbon 8*4() or 2 atoms = 1'5 or per cent. 8*57 Hydrogen 1*46 or 2 atoms = 0-25 — — 1*43 Iodine 90-08 or 1 atom = 15-75 — — 90-00 100-00* 17-5 100-00 This iodide is so easily decomposed, that we cannot determine the specific gravity of its vapour. It ought, from analogy, to be 9-7722. When a stream of chlorine gas is passed over it, decomposition takes jjlace, chloride of iodine is formed, and chloride of deutocarbo- hydrogen. Bromine decomposes it in the same manner. Potassium decomposes it without the assistance of heat. It is decomposed also by the alcoholic solution of potash There is obviously a close relation between aldehyden and de- fiant gas. Aldehyden is ... Chloride of aldehyden Bromide of alilehyden Iodide of aldehyden defiant gas Chloride of deutocarbohydrogen Bromide of deutocarbohydrogen Iodide of deutocarbohydrogen Aldeliyde .... Aldoliydic acid Acetic acid .... SECTION V. OF CHLOROFORM. This remarkable substance was discovered about the same time • Ami. ilcr Fharni. xv. 08. c* IP c* H' + Chl c* IF + Br c* H^ + lod c* IF + H c< IF Chl -1- II Chl c* M'' Br + I! Br c« IF lod + H lod c* II' () + H O c* IF ()2 + n c^ H'' 03 + II O CIlI.OROIOnM. 313 !Cil into me litis, II t'usea, •(' (lepo- innt gas I with a jUowisli, md then 13" and y lu8trc, of tears, the dark, ut on tlie sd. It is • qnantity 8-57 1*43 0-00 )0-00 determine iry, to be mposition jutocarho- otassium nosed also and ole- Chl Hr lod O O O lame time by M^f. Sonboiran* and Licbijr.f Somewhat later, its properties were investipited l)y M. Diiinas.J It is easily obtained by dirftiHiiif; a mixtnrc of alcohol andanueona solution of fh/oritf. of lime, or blnicliin>,' powder. It is u liin))id and transparent eolourh'ss li(|uid. Its smell and several of its other eharaeters have some unaloj;y with those of hydrovarbitret of chlorine. Its sj)e('itie j^ravity is 1*480. It boils when heated to the tem- perature of 141°^. The specific gravity of its vanour is 4*ll)i). It is not intlammablo. Mnt if a glass rod moistened with it be put into the tlume of burning alcohol we observe a yellow fuliginous flame. Ilydrocarburet of chlorine, in the same circumstances, burns with a large luminous tlame, the lower edge of which is coloured green. If vapour of chloroform be passed over red-hot iron or copper it is entirely decomposed. VVc obtain a metallic chloride covered with charcoal ; but no intlaninmble gas, if the exj)eriment8 of Liebig be accurate. If its vapours be passed through a glass tube raised to a dull red hcii' we obtain a small quantity of gas, a portion of which is absorbed by water, and another is combustible and burns with a green-coloured flame. The inner surface of the tube becomes black and is covered with a number of white filamentous crystals, which, (judging from their smell) have a great resemblance to Faraday's solid chloride of carbon. It is decomposed by lime at a dull-red heat, and no trace of in- flammable gas disengaged can be observed. At a higher tempera- ture carbonic oxide gas is obtained, occasioned by the action of the charcoal deposited on the carbonate of lime produced. Chloroform is not decomposed by potassium. It may be distilled off that metal without occasioning the smallest alteration. At the commenceme»199. Thus there can be no doubt whatever about the consti- tution of chloroform. It is a compound of I atom bicarburet of hydrogen with 3 atoms chlorine. SECTION VI. OF BIIOMOFORM. This compound, analagous to the last, was discovered by M. Dumas, in 1834.* It is obtained when a mixture of bromide of lime and alcohol, or acetone, is distilled, precisely as to prepare chloroform. The phenomena are the same, and we obtain a heavy oily-looking liquid. When agitated with sulphuric acid, and then left at rest, it falls to the bottom of the vessel, because it is heavier than concentrated sulphuric acid. It must be drawn off by a sucker, and rectified by distillation. When placed in contact with fused chloride of calcium it abandons the alcohol or water which it may have retained. The chloride of calcium swims, being lighter than bromoform. On this account frequent agitation is necessary to enable the salt to remove all the water or alcohol. • Ann. (le Chim. ct de Plivs. Ivi. 120. nnr far J ! IODOFORM. 315 Being less volatile than chloroform, it is more easily converted into bromide of potassium and formate of potash when boiled with a solu- tion of that alkali. The other properties of this substance have not hitherto been ascertained. But Dumas .oubjected it to ? chemical analysis, and obtained Carbon 5*32 or 2 atoms = 1*5 or per cent. 4*74 Hydrogen 0*47 or 1 atom =0*125 — — 0*40 Bromine 94*21 or 3 atoms = 30 — — 94*86 100*00 31-625 100 Thus the constitution of bromoform is precisely the same as that of chloroform ; namely, I atom bicarburet of hydrogen united to 3 atoms of bromine. There can be little doubt that the specific gravity of the vapour of bromoform is 8*7847, since it must be a compound of 2 volumes carbon vapour . = 0*8333 1 volume hydrogen gas . = 0*0696 3 volumes bromine vapour = 16*6666 2)17*5694 8*7847 united together and condensed into 2 volumes. SECTION VII. — OF IODOFORM.* This compound was first observed by SeruUas, in the year 1822,t who formed it by dissolving potassium in a solution of iodine in very strong alcohol. Afterwards, he discovered that the same substance might be formed in abundance by mixing together alcoholic solutions of iodine and of potash. J It was subjected to chemical analysis by Duma's, in 1834.§ Iodoform is a solid substance, of a sulphur-yellow colour, and crystallizes in plates. It is friable and soft to the touch. It exhales a smell analagous to that of safron. It is tasteless ; but its solution in alcohol has a sweet taste. At a temperature lower than that at which paper is charred it is decomposed into iodine, hydriodic acid, and charcoal. It is but little soluble in water ; but dissolves readily in alcohol, from which it is precipitated by water. The method of obtaining iodoform is to pour an alcoholic solu- tion of potash or soda into an alcoholic solution of iodine till the latter becomes colourless. Tli3 whole is then evaporated to dryness, and the dry residue is washed in cold water, which dissolves the iodide of potassium or sodium, and leaves the iodoform. If it be * This compound is described in my Inorganic Chemistry (vol. i. p. 182), under the name oi' sesguiodide of carbon. To that place 1 refer for its liistory, as far us Britisli chemists are conreriie-1736 Hence it is obvious ttiat the vapour of chloral consists of 4 volumes CHLORAL. 319 jtance Moral. »ral to when il. It srcury, in the t when icy de- ; oxide ses are r iron, le time Ived in est ease ution is ed, and iolution. d. We led with 5suines a erwards as de- 16-11 0-67 72-48 10-74 100-00 toins of Ipour of carbon vapour, 1 volume hydrogen gas, 3 volumes chlorine gas, and 1 volume oxygen gas, united together and condensed into 2 volumes. It has been stated above, that when hydrate of chloral comes in contact with an alkaline base it is decomposed into chloroform and formic acid. Now Chloral is . . C* H ChF 0» Chloroform is . . C^ H ChP There remains Add an atom of water H O and we have C* H 0=» which constitutes an atom of formic acid. Thus it appears that an atom of water being added to an integrant particle of chloral, enables it to resolve itself into chloroform and formic acid. It has been already stated that chloral dissolves in water, with the disengagement of heat, and that the solution, when evaporated in vaaio or spontaneously, crystallizes in rhomboids. These crystals have been subjected to analysis by Dumas, who found them composed of 1 integrant particle chloral . 18-(J2f^ 1 particle of water . . i - 1 25 19^; This analysis is confirmed by the specific gravity of its vapour, which Dumas found to be 2-76. Now Sp. Gravity. 5-1736 0-6250 :»lumes 1 volume chloral 1 volume vapour of water . 2 )5-71)86 2-8993 Thus the vapour of hydrated chloral is obviously composed of 1 volume chloral and 1 volume vapour of water, united together, and constituting 2 volumes. Insoluble chloral. It has been already remarked, that Liebig has given the name of insoluble chloral to a singular substance which is formed when chloral is left to the action of concentrated sulphuric acid at the ordinary temperature of the atmosphere. It is obtained wh jn we put into a phial, furnished with a ground stopper, chloral and six times its weight of concentrated sulphuric acid, and leave the mix- ture at rest for 24 hours. The chloral is converted into a white opaque solid substance. After a few days the whole is washed with water, taking care to press the white matter to powder, that it may b 85-40 5-70 100-00 35-125 100 Hydrate of bromal, like hydrate of chloral, is doubtless composed of ' ' ' . . . ? 125 1 atom bromal 1 atom water 125 30-25 It is obtained in crystals when bromal is exposed to the air, or mixed with a little water. The formation of bromal admits of the same explanation as that of chloral. SECTION X. — OF ETHAL.* An account of ethal is given in the Chemistry of Inorganic Bodies (vol. ii. p. 332). Since the publication of that work, it has been carefully examined by Dumas and Peligot,f who found it com- posed of Carbon 79*2 Hydrogen .... 14*2 Oxygen ..... 6-6 100-0 * The word et/ial is formed by joining together the first syllables of ether and alcuhol. t Jour, do Pharmacie, xxii, C"24. Ann. de Chiin. et de Phys. Ixii. 5. Y Ei'i' I'll n w ( M.I ! !, I I'l. I m r'.\ IV I ■ : 322 ALCOHOL AND ITS COMPOUNDS. Agreeing very nearly with the previous analysis of Chevreul. They consider its constitution to be ; 16 atoms carbon =12 or per cent. 79*34 1 7 atoms hydrogen = 2*125 — — 14*05 1 atom oxygen =1 — — 6*01 15*125 100 These a*onuc numbers may be resolved into 4 (C* + H*) + H O; that is to say, into 4 atoms of tetarto-carbo-hydrogen, and 1 atom of water. Now, when ethal is mixed with pure phosphoric acid in the state of powder and distilled, we obtain an oily substance much more volatile than ethal, and composed, according to the analyses of Dumas and Peligot of Carbon 86 Hydrogen . . . . . 14 100 This is equivalent to 16 atoms carbon = 12 or per cent. 85*71 16 atoms hydrogen = 2 — 14*29 14 100 It consists, therefore, of the same number of atoms of carbon and hydrogen, having been deprived of the water by the phosphoric acid. The specific gravity of the vapour of this oily matter was 7*846. Now, the specific gravity of 16 volumes carbon . . = 6*6666 16 volumes hydrogen = 1-1111 7*7777 It is obvious from this that the oily vapour is composed of 16 volumes carbon vapour, and 16 volumes hydrogen gas united to- gether and condensed into 1 volume. Here, then, we have a com- pound of 16 atoms carbon, and 16 atoms hydrogen. This new sub- stance has been distinguished by Dumas and Peligot by the name of cetene. It is a colourless oily liquid, which stains paper. It boils at 627°, and may be distilled over unaltered. It is insoluble in water, but very soluble in alcohol and ether, and has no action on vegetable colours. It is tasteless, and burns like the fixed oils with a white flame. When ethal is placed in contact with sulphuric acid no action takes place, unless heat be applied ; but when the mixture is heated over the water-bath and frequently agitated, the two substances combine, and form sulphocetic acid. When this compound is dis- solved in alcohol, and saturated with potash dissolved in alcohol, sulphate of potash is deposited, and sulphocetate of potash remains in solution with an excess of ethal. When the liquid is filtered and evaporated, the sulphocetate crystallizes. It is to be dissolved in This The mixti tion, ETHAL. 323 rhey H O; atom Lcid in I much ^ses of bon and 3sphoric tter was ;d of 16 lited to- a com- lew sub- le name . boils at in water, vegetable ite flame. 10 action is heated abstances A is dis- alcohol, remains tered and isolved in absolute alcohol, and crystallized a second time. This frees it from sulphate of potash, but it still retains ethal, from which it is freed by reducing it to powder, and digesting it in ether. Thus purified, it is in pearly-white scales. This salt was analyzed by Dumas and Peligot, who found it composed of 32 atoms carbon = 24 or per cent. 53' 28 33 atoms hydrogen =4-125 — — 9*14 1 atom oxygen =1 — — 2*21 1 atom sulphate of potash =11 — — 24*31 1 atom sulphuric acid =5 — — 11*06 45*125 100 These numbers are resolvable into 2 atoms sulphuric acid 1 atom potash . 2 atoms cetene . 1 atom water = 10 = 6 = 28 = 1*125 45*125 So that the basis of sulphocetic acid appears to be a hydrate of cetene, composed of 2 atoms cetene, and 1 atom water. When equal volumes of ethal and perchloride of phosphorus in fragments are put into a retort, they act upon each other with con- siderable violence. The mixture melts, becomes hot and boils, and a great deal of muriatic acid is disengaged. When the retort is heated, after the action is at an end, there passes over protochlo- ride cf phosphorus, then perchloride, and at last muriate of cetene. The product of this distillation is dlstii^^d again, with a little per- chloride of phosphorus. The liquid obtained is treated with water, which destroys the greater part of the chlorides of phosphorus con- tained in it, and disengages an oily liquid, which is purified by boil- ing it five or six times successively with water, and then distilling it off a small quantity of quick lime recently slacked. This liquid was analyzed by Dumas and Peligot, and found com- posed of 32 atoms carbon . . =24 33 atoms hydrogen . . =4*125 1 atom chlorine . . =4*5 32*625 C" H" H Ch This is resolvable into 2 atoms cetene 1 atom muriatic acid The liquid is, tiierefore, a muriate of cetene. MM. Dumas and Peligot consider spermaceii as a compound or mixture of margarate and binoleate of cetene and water. Its consti- tion, they think, is as follows : — \-t ■ir M ?! i il ■' R 324 KtilKltS. 2 atoms mnr«;aric iicld 2 atoms oleic, acid 3 atoms cctene 3 atoms water C70 ji«» ()« IP O'' Or, 2 atoms margarate of cetene C'"* H"*"' O" 1 atom binoleate of eetene C" H^" O' 3 atoms water . . H'^ O'"' CisH ll^^, ()i4 In p. 307, the relation of aldoliyde and several similar compounds to the base aldehyden has been shown. Chloroform, l)romoform, and iodoform, have for their base bicarburet of hydrogen, or C^ H. Thus bicarburet of hydrogen C"^ H Chloroform . . C'^ H + ChP Bromoform . . . C'^ H + Ih-"' Iodoform . . . C2 H + lod"* Chloral and bromal have for abase C II O^ or 2 (C^ H) Thus chloral is . . . C H O^ -j- ChP Bromal . . . C H O- ^ Br^* : :i Ct ' i ! i ill J CHAPTER II. OF ETHERS. It has been already stated that sulphuric ether consists of C ' H^ O, and that it possesses the characters of a base, being capable of neutralizing various (probably all) acid? and supporters of com- bustion. These new compounds are at present very inaccurately termed ethers. Thirteen of these ethers have been already described in the Chemistry of Inorganic Bodies. Since the publication of that work, the action of acids on alcohol has been very much investi- gated. The consequence has been the discovery of many new ethers, and the rectification of our ideas respecting some of those previously known. I propose to state these new facts in the pre- sent Chapter. I. The base of ether is C^ H'', a substance not yet obtained in a separate state, but to which Liebig has given the name of ethyl. But several of its compounds, with simple bodies, have been accu- rately examined. The following are the most important of these: — M K nc A PTAN. 323 1 Oxido of I'tliyl, or counnon etlior . (■' II' O 2 Clilorido of otiiyl, or inuriatic other ('' II* Chi 3 Uromide of t'thyl, or h\drohromi(' ether C II'' Ik 4 Iodide of ethyl, or hydriui .o ether C II" lod 5 Sidphiirot of ethyl, or incrcaptiin . C II* S+H S i) ('yaiiodidc of ethyl, or hydroeyanic ether C* H'' (C" Az) 7 Sulphohydrieether . . . C^'IPCHi^)!* Several of these compounds have been described in the Chemistry of Inorganic Bodies (vol. ii. p. 295), though the view of tlie consti- tution j^iven in that work is not always correct. 1. Common ether, described Ihid. vol. ii. p. 21)5. 2. Muriatic ether, Ibid. p. 310. 3. Hydrobromic ether, Ihid. p. 314. 4. Hydriodic ether, Ibid. p. 315. 5. Mercaptan and the two other bodies have been discovered since the publication of that work. We shall, therefore, give an account of them here. SECTION I. — OF MERCAPTAN. This name has been given by M. Zeise, professor of Chemistry, at Copenhagen, to a new compound which ho discovered about the year 1833, and which he caWad mercaptan, on account of the energy with which it acts on the red oxide of mercury.* M. Zeise obtained mercaptan by the following process : — A quantity of althionate of barytes, lime, or potash, was heated in a concentrated solution of the })rotosulphuret of barium. The pro- cess was conducted in a distilling apparatus. There distilled over along with the water an ethereal li(iuid, while the althionate was changed into sulphate. And, if the proportions of althionate and sulphuret were such, that each contained an atom of metal, the de- composition of both was complete, and nothing remained in the re- tort but neutral svdphato. Hardly any suljjhuretted hydrogen was disengaged in the state of gas; and neither the water nor the ethereal liquid contained any considerable (quantity of it. The ethereal liquid thus obtained was lighter than water. When separated mechanically from the water with which it had condensed in the receiver, then freed from the adhering sulphuretted hydrogen by agitation in water, and finally freed from water by means of chloride of calcium, it exhibited the following properties : — It was a colourless licjuid, with an exceedingly penetrating odour, having some analogy at once to that of assafuitida and garlic. Its taste was sweet. It inflamed readily, giving out the odour of tiul- phurous acid. When this liquid was distilled it was divided into two distinct liquids. To the first of these Zeise give the name of thialic ether ; to the second, that of mercaptan. It signitioj, lie s:tys, corpus mercuriioii mptaiis. S(H> Aim. ilo Cliim. et do Phvs. Ivi. 87. '^\ ii J I It f 320 KTIIKIIH. m W Till) thittlic other constUiitea tlie j^nuitest portion of tlio produce. It is not atFc'cted l>y an alcoholic solution of n salt of load. It does not act on tlio red oxide of luercury, annetrating. ^ity at 5J)° Its boiling iebig, only lor it dis- )n on vege- , II copious e of lead, oxide with lile at the uR'd when ul muriatic )erchloride y it into a bnsiderable the metal lin alcohol. Imd nitrate |cl chloride bed by the Jdry to the Imercaptan khich red composed MKIICAI'TAN. 327 4 atoms carbon . 5 atoms hydrogen 'i atoms sulphur I atom mercury s 3 0-«26 4 12-5 20-125 Zeise subjected mercaptan itself to an analysis, and found its con- •tituents 4 atoms carbon ... 3 atotns hydrogen . . . O'lT) 2 atoms sulphur ... 4 7-75 The analysis was repeated by Liebig with the same result. Thus the difference between mercaptan and the white mercurial sul't.'.ico is, that in the former an atom uf hydrogen replaces an atom of mercury in the latter. Zeise considers C* H' S'^ as the base of this substanc •, which he calls mercaptan,* But it is simpler to view the base as ethyl, and to consider mercaptan as a sulphuret of ethyl or C* li' S united to an atom of sulphuretted hydrogen. Mercaptan is a hydrate of this substance, and he proposes to call it , ydrome ■ aptuin. The white mercurial substance he calls mt/captide qfmemiry. Zeise analyzed the mercaptide of gold, and found it c.tui^)osed of 1 atom mercaptan 2 atoms gold Or better, C* IP S + Au-" S. Mercaptide of platinum is C* H* of mercury melts at 187°. The mass, chlorate of potash after it has been fused. It is without smell, but emits a peculiar odour when rubbed. At the temp jrature of 257° it begins to deposit mercury. At 347° it is completely decom- posed, giving out, among other things, an oil resembling thialic oil. Mercaptide of mercury is insoluble in water, and but little soluble in alcohol. It may be melted in a concentrated solution of potash without undergoing any alteration. Tbe acids scarcely act upon it at the ordinary temperature, except ni^r:. cid. Mercaptide of gold is an amorphous mass without lustre and colourless. With water, alkalies, and acids, it behaves nearly as the mercaptide of mercury. It may hr. heated to 428° without any sensible alteration. When distilled at a somewhat higher tempera- ture, it gives a peculiar oily substance, without disengagement of gas. Gold remains apparently pure. Mercaptide of platinum when distilled is transformed into sulphu- ret of platinum, exhibiting, at the same time, the phenomenon of C« H' fc' Au-* S^* + PI. The mercaptide after congealing, resembles n '111 Ignition. Corpus mircurio nptttm. 1 ! j 1 1 :! . ! : L i I ' 328 ETHERS. Mercaptides of potassium and sodium have always an alkaline re- action. When dry, they support a temperature of 212° without alteration. But when their aqueous solution is heated it is easily altered. SECTION II. — OF CYANODIDE OF ETHYL, OR HYDROCYANIC ETHER. This ether was discovered by M. Pelouze, in 1834.* It may bo obtained by heating gently a mixture of equal parts of cyanodide of potassium and althionate of barytes. The liquid which distils over is to be mixed with from four to five times its bulk of water to wash away the alcohol and hydrocyanic acid which it may contain. It is kept afterwards for some time at a temperature between 140° and 160°, and finallv distilled over chloride of calcium. It is a colourless liquid, having a very strong alliacious odour. Its specific gravity is 0*78. It boils at 179°^. Water is a very bad solvent of it ; but alcohol and ether dissolve it in any proportion. It acts with great energy on the animal economy. When pure it does not precipitate nitrate of silver. Potash ley decomposes it with great difficulty, and only when much concentrated. Its constituents, according to the analysis of Pelouze, are 6 atoms carbon . . . =4*5 5 atoms hydrogen . . = 0*G25 1 atom azote . . . = 1'75 We may consider it as a compound of I atom cyanogen 1 atom ethyl 6-875 C'^ Az SECTION III. — OF SULPHOHYDRIC ETHER. This ether was formed by M. Lowigjf in 183G, by the following process: — Oxalic ether was mixed with sulphuret of potassium, prepared by decomposing sulphate of potash by means of charcoal. The sulphuret was reduced to a fine powder, and while still hot, it was introduced into a retort, and pure oxalic ether poured over it till the whole formed a thick mucilaginous mass. This mixture was exposed for some hours to a moderate heat, taking care to avoid all contact of water. The heat was then increased, and the distillation continued till the oxalate of potash formed began to be decomposed. The product of this distillation consisted of a mixture of sulpho- hydric ether, and oxalic ether. It was agitated for a considerable time with a concentrated solution of pure potash, or of sulphuret of barium, which decomposed the oxalic ether. The sulphohydric ether thus purified, was decanted and rectified over chloride of calcium. Its purity was ascertained by agitating it in a solution of sulphuret t)f barium. It occasioned no precipitate in that liquid. * Jour, (ic riiaiii;. x.v. J'OO. f Poa-trriiddii'V- Aiiimlcn, xxxvii, .WO. ^,1 i SULPHOHYDIUC KTHEI!. 329 Sulphohydric ether is lighter than water and has an ethereal, but very disagreeable odour of assafcetida. A single drop is sufficient to spread this smell over a large space. Its taste is sweet. It has no action on vegetable blues. It is little soluble in water, but it communicates to that liquid its taste and its smell. It may be mixed in all proportions with alcohol and ether. It burns with a blue flame, disengaging sulphurous acid. It is not altered by ex- posure to the air. When boiled with an aqueous solution of potash, it is not decomposed. But if we distil it off hydrate of potash in fine powder, we obtain sulphuret of potassium and alcohol. But this decomposion goes on slowly, and a great part of the ether is disengaged without decomposition. Potassium decomposes it when assisted by a moderate heat ; but the decomposition soon stops, because the sulphuret of potassium formed covers the potassium re- maining in a crust, and thus hinders any farther action. No hydrogen gas is disengaged during this decomposition. Sulphohydric ether has no action on red oxide of mercury, and by this character it is easily distinguished from mercaptan. Yet it precipitates some heavy metallic salts. Thus it throws down the alcoholic solution of acetate of lead yellow. When mixed with a concentrated alcoholic solution of sulphuret of potassium, a white substance is precipitated, having considerable resemblance to raer- captate of potassium of Zeise. Probably this ether might be obtained also by distilling a mix- ture of sulphuret of potassium and dry althionate of barytes. f '■ '! ,lt over it ixture are to nd the to be 3ulpbo- ilcrable uret of jhydric ride of ition of luid. II. The next set of bodies to which the term ether has been applied, are in fact not ethers, but ought to constitute a different class of bodies. Their base is not C* H^ but C^ H* or tetarto- carbo-hydrogen. They are the following :- 1 Light oil of wine 2 Chloric ether 3 Bromic ether 4 Iodic ether 5 Acetal . 6 Sulphocyanic ether C^ H* C^ H^ + ChP* C* H* -h Br2 C* H* + lod^ C* H^ -h Hi () III. The third set of bodies classed among the ethers, consists of chemical compounds of sulphuric ether and an acid. Ether {sulphu- ric ether) possesses the characters of a base and probably neutralizes all acids. But the only compounds of this kind hitherto examined are the following ; — 1 Nitric ether . C^ W O + Az O^ 2 Carbonic ether . C^ \V> () + C O^ 3 Oxalic ether . C^ HM) + C^ 0=* 4 Formic ether . C* H^ () + C^ H O^* 5 Succinic ether . CMP O + C^ IP O'^ I:.jO. * Sec Ciieiiiiilry of Inorfraiiic Uodios, ii. 3"j;?. ': I i . 1 ! ! 1'- i : I !|5 \ n > f i ^1 M. ETHEIIS. c* w O + C^ H» 0' c* H» O + C'^H** 0» c* H« + C* H^ 0^ c^ H' O + C* H^ 0* c« H'' O + C^ H^ 0* c^ H^ O + C« H* 0^ c^ H« O + C K^ 0' c* H' O + C ' IP 0* c^ H-' O + C'"H» o» c* H« o + c« H6 03 c H'^ + C'^H'- iQ2 c H'- + C2 ChlO' c H^' + 2(( D^A LzO) + 3(HO) c H^ O + C2 Az Chi 330 6 Acetic ether 7 Benzoic ether 8 Malic ether 9 Citric ether 10 Tartaric ether 1 1 Mucic ether 12 Pyrocitric ether . 13 Pyrotartaric ether 14 Pyroraucic ether . 15 Suberic ether 16 -^nanthic ether . 17 Chlorocarbonic ether 18 Cyanic ether 19 Chlorocyanic ether 20 Elaidic ether . C^ H'^ O + C^^i^^Qs Such of these salts, improperly called ethers, as have not been inserted in the Chemistry of Inorganic Bodies, will be described in the following Sections. SECTION I. — OF NITRIC ETHER. Described in the Chemistry of Inorganic Bodies (ii. 317). SECTION II. OF CARBONIC ETHER. This ether was discovered by Dr Ettling in 183G.* M. Liiwig of Zurich had announced, that when potassium or sodium is made to act on oxalic ether, the ether is decomposed into oxalic acid, croconic acid, carbonic oxide gas, and sulphuric ether. M. Ettling repeated the experiments of Liiwig, but obtained very different results. No croconic acid was formed, but a red resinous-looking substance, soluble in alcohol, ether and water. The ether produced, instead of being sulphuric, he found to be carbonic ether. The process followed was this : — A fragment of sodium was put into anhydrous oxalic ether exempt from oil of wine. No action was observed while the liquid was cold ; but when heat enough was applied to soften the sodium, it separated from the crust of oxide with which it was environed when introduced into the liquid. Then yellowish white flocks were formed round the sodium, which gradually deepened in co- lour, and at last assumed a dirty-red tinge. The sodium appeared brilliant and no gas was given off. But when the temperature was raised to 26(i°, gas began to issue from the sodium. When this ni tter was collected, it measured 45*7 cubic inches from 100 grains of oxalic ether. The properties of this gas were similar to those of carbonic oxide, but from the analysis of Ettling, by means of oxide of copper, it seems to have been a mixture of 12"(i volumes of carbonic oxide, and 1 volume of hydrogen gas. When new pieces of sodium introduced occasioned no farther * Jour, (le Pliartuacic, xix. 17. VV( CARBONIC ETHER. 331 KHO) lot been ribed in 1. Lowig I is made lalic acid, . Ettling different s-looking voduced, 3r. The Llic ether jtlie liquid B sodium, pnvironed tte Hocks ^d in co- [appeared nperature When Ifrom 100 limilar to |by means volumes lo farther evolution of gas, the matter in the retort had a deep-red colour, a syrupy consistence while hot, but almost solid when cold, and pos- sessing a peculiar smell. It was completely soluble in absolute alcohol, and when dried in vacuo, over sulphuric acid, formed a mass having a glossy lustre. When reduced to powder, it had a reddish- brown colour, and was very easily moistened and agglutinated together. When the mass before being dried was put into water, it dissolved readily, and the new ether separated and swam on the surface of the liquid. It was washed with water, and then distilled with a new portion of water. When it still contained oxalic ether undecom- posed, it was rectified on a small quantity of sodium, after having been previously deprived of water by digestion with chloride of calcium. Finally, it was heated in a small retort till its boiling point became constant, in order to deprive it of any alcohol that it might contain. Thus purified, it possessed the following properties : — It is a colourless and very fluid substance. Its specific gravity is 0-976 at 66°. It boils at 257". It burns with difiiculty at the end of a glass rod with a small blue flame. Its taste is hot and aromatic, its smell cooling, having some resemblance to that of oxalic ether. When mixed with an alcoholic solution of caustic potash, no action is observed while the mixture is cold, but when a slight heat is applied it becomes muddy, and a white bulky precipitate falls, which, when a very little water is added, unites into drops of oil at the bottom of the liquid. The addition of an acid occasions then a lively eff'ervescence, by the evolution of carbonic acid gas. The liquid after being neutralized shows no trace of oxalic acid ; nor is any formic acid shown when salts of silver or mercury are added to the liquid. It was analyzed by Ettling, and found composed of Carbon 50-25 or 5 atoms = 3-75 or per cent. 50-85 Hydrogen 8-52 or 5 atoms = 0-625 — — 8-47 Oxygen 41-23 or 3 atoms = 3-00 _ _ 40-68 100-00 7-375 These numbers may be resolved into 1 atom sulphuric ether . C^ 1 atom carbonic acid . C 100 H^ O 02 C W 03 M. Ettling determined the specific gravity of the vapour of this ether and found it 4-243. Now the weight of 1 volume ether vapour is . 2-5694 1 volume carbonic acid gas . 1*5277 4-0972 W^e see from tliis that carbonic ether is a compound of 1 volume ether vapour, and 1 volume carbonic acid ga? united together and condensed into 1 volume. ^^1 ! Mi Sit h r ^l! 332 ETIIKnS. ■ i ^! P .nil ;■ SECTION III. — OF OXALIC ETHKU. This ether has been described at sufficient length in tlie Chemis- try of Inorganic Bodies (vol. ii. p. 322). We introduce it here to explain the nature of the following compounds : — 1 . Oxamethane. M. Dumas* passed a current of dry ammoniacal gas over a givi n quantity of pure oxalic ether. The matter being solidified, it was heated, and the current of gas continued for some time longer. The substance thus obtained he called oxamethane. 100 ether treated in this manner furnished 7 (i or 77 of oxamethane. It melts at .n. Temperature below 212", but is not volatilized under 428°. When sublimed it crystallizes in beautiful radiated plates. It dissolves in alcohol, without alteration. When put into water that liquid be onics very acid, and probably alcohol and binoxalate of anmionia are formed. It was analyzed by Dumas and Boullay indirectly, and aft.erwards directly by Dumas, with the following result: — Carbon .... 40-725 Hydrogen .... 5-990 Azote • . . - • 12-345 Oxygen .... 40-940 100-000 It was analyzed by Mitscherlich w ith the same result.f The mean of both analyses is Carbon 41-50 or 8 atoms = ti or jier cent. 41-02 Hydrogen ()-0() or 7 atoms = 0-875 — — 5-99 Azote 11-81 or 1 atom =1-75 — — 11-97 Oxygen 40-()3 or 6 atoms = 0-00 — — 41-02 100-00 These atoms may be resolved into 2 atoms oxalic acid 1 atom ether 1 atom annnonia 14-625 100 C^ 0« C O H"* H^' Az Minus I atom water C« 0" H« Az O H C« ()« IF Az So that it wants an atom of water in order to be a compound of one integrant particle of oxalic ether, and one integrant ])nrticle of oxalate of ammonia. It is therefore a compound of oxamide and oxalic ether. Hence the reason wbv by Mitscherlich it is denom- inated ethcroxnmide. 2. Etheroxulate of potash . It was shown by Liebig that oxalic ether has the pro})erty of combining with bases like an acid. Mitscherlich has analyzed the etheroxalatc of j)otash, and found it composed of * Ann.de Chim. rt tlr I'liys. liv.-.24l ; mikI I,if'lli^^ Anii.ilcn dor riiiiriir.u'ic.ix. 1-'!). f- I''>l:::( riliirt'V Aiiiialcn. x.wiii. J.iiJy. SUCCINIC KTHEI?. 333 Id of one Irtide of ude and denoui- IVu' etlier Kc\ievVK-li losed ot Carbon 31*16 or H atoms = (5 or per cent. 30*57 Hydrogen 3*17 or 5 atoms = 0*625 — — 3*18 Oxygen 35*65 or 7 atoms = 7 Potash 30*02 or 1 atom = 6 _ — 35*67 _ _ 30*88 100*00* These may be resolved into 2 atoms oxalic acid . 1 atom snlphuric ether 19*625 100 C* o« C* H^ O C» IP O^ imitod with an atom of potash. According to Mitscherlich, this salt is obtained when oxalic ether is dissolved in absolute alcohol, and as much hydrate of potash pre- viously dissolved in obsolute alcohol is added as is just sufficient to neutralize half the oxalic acid contained in the ether .f If more potash be added, the oxalic ether is decomposed. The salt being insoluble in alcohol, precipitates in crystalline plates. They are to be collected on a filter, and washed with abso- lute alcohol, and then dissolved in hydrous alcohol, which will leave undissolved any oxalate of potash that may be mixed with the ether salt. We obtain the etheroxalate of potash by exposing this solution to spontaneous eva])oration, it falls, though with difficulty, in crystals. It is exceedingly easily decomposed. The addition of even a weak base, or a salt of lime, or a metallic oxide, as oxide of cobalt, lead, or copper, occasions always the formation of a metallic salt and the separation of the ether in the state of alcohol. The best way to combine the acid of this salt with other bases, is to precipitate the solution of the salt in hydrous alcohol with sulphuric acid, and to saturate the acid thus set free with carbonate of bai*ytes, or carbo- nate of lime. If we evaporate the solution to the consistence of a syrup, we obtain the salts with tl ese bases in crystals. These may be decomposed by neutral s' Iphates, and thus other etheroxalates obtained. If we attempt to aturate the free acid of etheroxalate of potash with oxide of copper, we obtain nothing but an oxalate. The acid cannot be obtained iu i\ concentrated state either by eva- porating it on the water-bath, or in vacuo. The solution thus treated shoots into crystals of oxahc acid. SECTION IV. OF FORMIC ETHER. f Described in Chemistry of Inorganic Bodies (vol. ii. p. 330). SECTION V. — OF SUCCINIC ETHER. M. J. d'ArcetJ has discovered an ether of succinic acid, it may be obtained by mixing together 10 ])arts of succinic acid, 20 parts alcohol, and 5 parts of concentrated muriatic acid, and distilling * Poggenilorf's Annalen, xxxiii. 332. + Lelirbuch der Chiin. 2 Aufl. i. 6114. J Jour, fiir pract. Ch. iii. '213. »na »•' ||. :m 'i ^M ETHERS. the mixture. What passes over is to be returned back into the ret'irt an J li^^ Ued again, and this process must be several times repeated. At last an oily-looking body will be observed in the retort, which, vhen treated with water, gives out succinic ether. It is washed with cold water in a retort, containing a thermometer, and it is to be gradually heated, but not to the boiling point. Oxide of lead is now added, and the ether distilled off. It is a colourless transparent liquid, not unlike ben/oip other, and when burnt ha-- a sour smell like it. It has an oi!y feci ; a, s]k:' ific gravity of l*03t', and boils when heated to U'/^ , /according to the analysis of d' Arret it is composed of 1 atom ether 1 at(jm succinic acid C* H2 0=* it fil:f ml i i C8 w o* When boiled with potash it is decomposed, i'nd alcohol pai Q3 over. The vapour of this ether has ;i spocjf'.c gravity of TrSii at the temperature of 32°, anl when tha barometer stands at 29*&i inches. Now, the specilic gravity of 8 volumes carbon = 3'.3333 7 2 hydrogen = 0'48(il oxygen = 2-2222 6-0416 It is evident from this that these 7 volumes of gaseous matter are condensed in the vapour of ether into I volume. Chlorine decomposes this ether by the assistance of light, and succinic acid is separated in crystals. SECTION VI. — OF ACETIC ETHER. ' In the Chemistry of Inorganic Bodies (vol. ii. p. 325) I have given an account of this ether, and have stated its composition according to the analysis of Dumas and BouUay. It has been since subjected to a new analysis by Liebig, who prepared it by distilling a mix- ture of 16 parts anhydrous acetate of lead, 5 parts sulphuric acid, 4^ parts of absolute alcohol. He got from this mixture cix parts of acetic ether. This ether was deprived of all water by digestion with chloride of calcium, and analyzed. Liebig obtained Carbon .... 53-60 Hydrogen .... 9*68 Oxygen . . . . 36- T 2 This gives the formula 100-00* • Annalen der Pharinacie, v. 34. 335 latter are CITrtIC ETHER. 8 atoms carbon -- a 8 atoms hydroeen ^ i °' ^^' '""*• ^4-54 4 atoms oxyrren - d ~~ ~~ ^'09 " ~J — — 36-37 These a.„„, , ^^ M_^_^ ,^J atom sulphuric eti.er r' v, r. ' "torn acetic acid . ; g' W o See ae„,Jl^/r '""r '"~™"^ ""^»- ^•n>slr„ oflnorgm,, Bodu, (vol. u. p. ggg, ^ery short a^S' "{ ^T-^"'"'' *'"'«» (vol. ii „ „n , He put into a ^etT'"^ " "»' ™-ty "-e ^Z as .Kf ThSafd"' 90 parts citric acid crystals the alcohol l^pioved '??^^^'' ^™°"nted to Xuf ! S^T'^ ^^^ 'nima ctoat'tf "'A<^^^i Zl^:Zt '"''^ ""- P'oach'cs so nearly., r„fi""' """ ""= P"'"' ofvl,iW?r''''' - without des.r;s^.t^-s:;»o?H'^~^^^^^^^^ ^ '"• ^t begins to lose its I :m m. •An„.deChi™.e,dePh,s.|.iii.20,. 3:}<) ETHKItS. ;il 'I' iili'i: If fi. u limpidity at 248°. It heconios red at 3\S^. It begins to boil and to bo decomposed at r)41''/r, a brown oily matter passing over. Soon after, *'ater containing alcohol i)asses over, and, finally, car- buretted hydrogen and citric ether. A (juantity of charcoal remains in the retort. Citric ether is neutral, and, when burnt, leaves no residue. It is soluble in ether, in alcohol, even though weak, and a little solidilc in water. An aqueous solution of it becopies acid by keeping, and the change is more rapid when heat is ap})lied. If we boil citric ether with a solution of potash or soda, we obtain alcohol and citrate of potash or soda. Licpiid ammonia has no immediate action, but, by degrees, it acts like potash or soda. Amniouiacal gas has no action whatever. Harytes and strontian water do not precipitate a recent aipieous solution of citric ether. Cold nitric acid dissolves this ether, and when the solution is mixed with water the ether does not separate. When the solution is slightly heated a lively action takes place ; red vapours arc disengaged, and the residue has the smell of liyponitrous ether. If the heat be long continued and the quantity of ether considerable, oxalic acid is formed. Concentrated sulphuric acid immediately deepens the colour of citric ether. The acid dissolves the ether without the assistance of heat, but, when water is added to the solution, the ether separates again unaltered. When the suli)huric solution of the ether is heated to 158° a reaction conunences, and becomes more violent as the temperature is raised : alcohol and sulphuric ether are disengaged, and a thick transparent matter remains which is solul)le in water. Cold muriatic acid dissolves citric ether and separates from it again when diluted with water. When the solution is hcatiHl suffi- ciently muriatic ether is disengaged, together with a little jilcohol, and no citric ether is found in the residue. When potassium is placed in contact with citric ether gas is dis- engaged, but it stops as soon as the surface of the metal becomes oxidized. Citric ether dissolves iodine and bromine. When the solution of bromine is heated all the bromine is disengaged and the residue is acid. But the solution of iodine (I")es not lose its iodine nor become acid when heated. Citric ether was analyzed by M. Malagutti, by passing it through red-hot oxide of copper. He obtained Carbon 50-40 Hydrogen . . . . 7*31 Oxygen . . . . 42-29 100-00 Now, these numbers correspond with 8 {itoTus car])on = (i or jjcr 7 atoms hydrogen = 0-825 — cent. o atoms oxygen = 5-0 11-825 50-74 ()-97 42-21) 100-00 MUCIC ETHEH. 337 jil and over. y, car- cinains . It is ilviblc in and the ic ether itrate of on, but, s has no ccipitatc dissolves ther does ily action I has the il and the colour ot* ^stance of separates r is heated ent as the isengaged, u water, tes from it 3atvHl suffi- le jilcohol. Las is dis- jil becomes When tiie led and the its iodine , it through But 1 atom citric acid is I atom sulphuric ether C« IP O* C« H^ 0» It is obvious from this that citric ether is a compound of 1 atom citric acid, and 1 atom sulpliuric ether. So that it agrees in its constitution with all the othor acid ethers.* SECTION X OF TARTARIC ETHER. See Chemistry of Inorganic Bodies (vol. ii. 231). SECTION XI. — OF MUCIC ETHER. This very curious ether was discovered and examined by M. Malagutti, cliemistto the Porcelain Manufactory at Sevre, in 183(j.t He obtained it in the following way : — One part of mucic acid was mixed with 4 parts of sulphuric acid, and the mixture gently heated. It became tirst of a delicate red colour, then crimson, and the colour gradually deepened till it became black. It was taken from the lire, hermetically sealed, and after an interval of 12 hours was mixed witli 4 parts of alcohol of 814, and the whole was left at rest for 24 hours. The whole had now become solid. To rem.ove it from the vessel alcohol was poured in, it was briskly agitated, and then thrown upon a filter. To rende:' it quite pure it was repeatedly dissolved in boiling alco- hol, from which it was deposited on cooling in a crystallized state. The crystals are right four-sided prisms. At tirst they appear taste- less, but they leave an impression of bitterness in the mouth. They melt at 33(5°^, and when cooled down to 275°, congeal into a crys- talline mass. Just before melting, a little brownish oily liquid is discharged from them. If after the fused crystals have solidiiied, we allow the temperature to sink to 158°,, and then raise it again, fusion takes place at the temperature of 302*^. At 338° the matter blackens, and is decomposed. The products of the decomposition are alcohol, water, carbonic acid, j)yromucic acid partly crystallized on the upper part of the retort, acetic acid, carburetted hydrogen, and charcoal. The specific gravity of crystallized mucic ether is I" 17. It is insoluble in ether, very soluble in boiling, though but little soluble in cold alcohol. 1000 parts of alcohol of t)'8l4, at the temperature of ()0° dissolve only fj-4 parts of mucic ether. It is very soluble in boiling water, and the solution, on cooling, deposits large crystals, having the form of right oblique four-sided prisms, two of the opposite faces being usually much broader than the other two. These crystals have a specific gravity of 1-32. 100 parts of water at 59° dissolve 2*27 of them. Tliey melt at 330°}., and the fused mass concretes again when cooled down to 251°.t. If we sink the temperature to 158°, & vn v\ li * Ann. do Cliiui. ct do Phvs. Ixiii. 107. t Ibid. 86. ai I 338 ICTHKItS. w nml tlion Uo.at a rocitric ether s H 4 f 'If "'•«'"^'''^''-v. Tl c noc'wi ''''^'' ««-<'eIy soluble „\',to; 'Y\ ''' 1 Y'-^^-^'^'-i^- • '0 « Th""^ "^ C a O =4«0'25 f'yi-otartaric ether of 1 atom j)yrorartaric acid i atom ether C^H^o^ 11.625 C' fP 03 = 7.12-5 CMP o =441 «25 11-75 This ether Z'Z ""rr "^'""""'^ — «ac? tune into the retort Mi) i *™''^' returning the nrJ. ! lilSf IS?!:- ffravitv l-Qo? J'^"*-- i.iste eoolino-. sh-irr. o„ i , P "^ "^o tnat of be dSiltd • f """^ "^^'It at [)3° 'boi : i 1*^ ^'*^'^"- Specific ^ "Jhtijiea over wifhnnf i " .'l» , dous at about 4n«o „ j "IS etlier was analyzed bv M Af i 3^ f^y M. Malagutti, and found composed of arompyromucicacid . pio m r»5 ^ '"'""= ""ight. ' atom ether ,., i], ^ = ' ^"875 • ^ H^ O = 4.(j25 H ;l 'M * A"", lie Ciiiui. et ,le Pi.v s- Ixiv. '279. i '- ■ * » ll ' i! I i" ijiiwi' !i 1l !h 340 ICTIIICItS. WIuMi a current of pure •.")<» •27- 7 or- 4 atoms = 4*0 _ _ 27*83 Oxygen lOO-O 14-37r> These inunhers may he resolv((d nito I atom suhoric aeid . C H** O' I atom eth r . . . C* M^ O 1 ()()'()(» (Jli III. Qi Showing the constitution of the etlier. SECTION XV. OF (KNANTHIC KTIIKII. 'I'his remarkable ether was first j'xamincd by Liebijr and Pelonze. It is to it thatt'ic peculiar odour which distiu<;uish('s \yines is owing.* When i; i!.' • (|uantitio9 of wine are distilled, w(! ol)tain at the end of the pro( est- a small (|uantity of an oily licpiid. The same liquid is obtained when we distil the lees of wine, especially what is depo- sited at the !)ottom of the cask after the fernu;ntation ha?! he ...1 Wi 1 I! i.'i • !'^ I ! ihi They found the specific gravity of the vapour of this ether 10-508. Now, 18 volumes carhon weigh . 7*5 18 volumes hydrogen — . 1*25 1^ volume oxygen weighs . 1'666G 10-416G This etiier is obviously a compound of 1 atom ocnanthic acid . C* H'' O^ 1 atom ether . . C^ W O C'« H'« 0=* SECTION XVI. — OF CHLOUOCARBONIC ETHER. M. Dumas* filled a glass globe with 915 cubic inches of chlorocar- bonic acid gas, and poured into it 4G4 grains of anhydrous alcohol. The alcohol almost immediately became hot, and assumed an amber colour. The vessel was agitated, and when the action ap- peared at an end, air was allowed to enter to replace the gas ab- sorbed. In about a quarter of an hour the liquid was taken out of the vessel, and mixed with its own volume of distilled water. Two layers were immediately formed, the heaviest had an oily aspect, and resembled oxalic ether. The ether was watery, and contained a good deal of chlorocarbonic acid. The oily liquid being distilled by the water-bath from chloride of calcium and litharge, exhibited all the characters of an ether. It forms a colourless liquid, not acting upon litmus paper. It boils at 201°. Its specific gravity is 1*133, at the temperature of 59°. It burns with a green-coloured flame. Its odour is agree- able when air, containing only a little of it, is breathed, but when its vapour is abundant it is suffocating, and occasions intense cough- ing and tears. The specific gravity of its vapour was found to be 3'82. When placed in contact with hot water it renders it strongly acid. Concentrated sulphuric acid dissolves it. The solution, especially when heated, gives out abundant vapours of muriatic acid. If we continue the heat the acid blackens, and gives out an inflammable gas. M. Dumas analyzed this ether, and found it composed of Carbon 34*2 or 6 atoms = 4*5 or per cent. 33*03 Hydrogen 5-0 or 5 atoms = 0*625 — — 4*59 Chlorine 30-7 or 1 atom =4-5 _ _ 33-02 Oxygen 30-1 or 4 atoms = 4-0 _ — 29-36 100-0 13-625 100-00 This is resolvable into C^ Ch O" + C^ H'' O ; that is to say, an ;.toui of an acid, composed of Aim (Ir ''him. cl He Pliv?. Ii\. 22^. 'fissc in re but sulplj Into I drive in li^ that I cant'l decol i n CYANIC ETHER. 343 2 atoms carbon I atom chlorine 3 atoms oxygen = 1-5 = 4-5 = 3-0 9-0 Constituting a new acid, the same as oxalic acid united to an atom of chlorine. C* H^ O is sulphuric ether. It is,' therefore, a compound of 1 atom ether, and 1 atom of a new acid not yet observed in a separate state, and not yet distinguished by a name. The specific jjravity of the vapour of this ether corresponds with its analysis. For the specific gravity of 6 volumes carbon vapour . = 2*5 5 volumes hydrogen . . = 0*3472 1 volume chlorine . ;= 2*5000 2 volumes oxygen . . = 2*2222 2)7*5694 3*7847 We see that the 14 volumes of atoms constituting this vapour are condensed into 2 volumes. SECTION XVII. — OF CYANIC ETHER. This remarkable ether was discovered by Liebig and Wiihler, about the year 1830.* They obtained it by passing liquid cyanic acid into alcohol. The acid was rapidly absorbed. The alcohol became hot and began to boil, but no permanent gas was evolved. There was gradually deposited a considerable quantity of a white crystalline powder. This substance was cyanic ether. Cyanic ether has neither taste nor smell, nor does it produce any alteration on litmus paper. It is scarcely poluole in cold water. It is even difficult to moisten the crystals with water, they resist the action of that liquid as tallow does. It is more soluble in hot water, but the greater part precipitates again when the solution cools. It fiissolves readily in hot alcohol, and is deposited as the liquid cools in regular prismatic crystals. It is soluble also in boiling ether, but not so much so. It appears to dissolve in boiling nitric and sulj'huric acids without decomposition. When heated it melts into a clear liquid, which again concretes liito crystals when allowed to cool. When thus melted, a portion is driven off in a vapour, destitute of smell. This vapour is deposited in light-white flocks, like those of oxide of zhic, which fly off when that metal is burnt in the open air. This vapour catches fire at a candle, and burns like cyanogen gas. When heated in a retort it partly sublimes unaltered, and is partly «lecoraposed. When raised to a temperature at which concentrated * I'dygcndori's Annalcn, x\. '3'.)j. m- i- '1!.:': ^.1 - r Il 1' ^' 344 KTHEKS. llll I, H If sulphuric acid smoke?, it boils violently, and a liquid passes over, which is alcohol. What remains in tin retort is solid cyanuricr acid, which may be dissolved in distilled water, and crystallized. It was analyzed by Liebig, and found composed of Cyanogen .... 50"7()45 Carbon . . . . 17*85;J0 Hydrogen .... (3-0420 Oxygen .... 25-3405 100-0000 These numbers give the formula 2 atoms cyanic acid = 8*5 or per cent. 51 52 4 atoms carbon =3 — — 18-lS M atoms hvdroiien =1 — — ()-0(J 4 atoms oxygen =4 — — 24-24 l()-5 100 These atomic quantities may be arranged as follows : — 2 atoms cvanic acid 2(C-^ Az ()) = C A/' O' 1 atom etiier . . . C H^ O 3 atoms water 3(H O) IF O^ Making altogether J.(C^ Az O) + C 11"> O + 3(11 ()). atomic weiijht of which is l(i-5, as in the formula. Tlu« SECTION XVIII. — OF CHLOUOCYANIC ETHER. This ether was discovered by M. Aime, in the year 1837.* It may be obtained by passing a current of chlorine through absolute alcohol, holding cyanodide of mercury in solution, and collecting the product of the distillation. What j)asses over is a mixture of alcohol and mi ethereal licjuor. The alcohol may be separated by water. The ether remaining is an oily-looking liquid, having a specific gravity of 1-12. It boils at 122". It burns with a purple ilame, and the vapoUi produced precii)itates nitrate of silver. Alcohol and ether dissolve it. Watc throws it tlown from its alcoholic solu- tion. Licpiid ammonia decomposes it instantly with the disengage- ment of gas. The alcoholic solution undergoes spontaneous decomposition in 24 hours ; and there remains a crystalline substance, which dis- solves very well in water. When heated with water it is easily decomp.oscd. Its smell is similar to that of chloride of cvano<>cn. It irritates the eves. Its taste is very similar to that of liydrocyanit; acid. Its constituents, according to AimO, are 1 atom chloride of cyanogen ('- Az Cli 1 atom ether . . . C H'' O It seems to follov,-, from this compound, that the cliloride of cvanoLien is an acit!. since it conii'iucs wids and neutralizes ether. ♦ Aim. .1 ( iiuri el ili I'liv? I» ■ '■.'tom cf ''".vidic acid. It follows from this analysis, that an atom of elaidic ncid is C^^ H'''' O'', and consequently that its atomic weight is 33'375, l>y a similar process, Laurent prepared margaric ether and oleic ether. The specific gravity of this Inst ether is 0-871. IV. The fourth set of bodies, which have by some been classed among ethers, are certain acidulous salts, consisting of 1 atom of ether united to 2 atoms of an acid. They may be considered as the ethers of the last set, united each to an additional atom of the -•.Old, which is combined with and neutralizes the ether. The fol- lowing are the principal salts of this kind hitherto examined: — 1 Heavy oil of wine C H' (H* ()*) + S O^ C ' H^ 2 Althionic acid 3 Phos])hovinic acid 4 Oxalovinic acid 5 Tartrovinic acitl C H C^ H O -h 2 (S O^) + H () O + 2 (Ph O'i) () + 2 (C- ()') + H () () -b 2 (C ir^ ()') + II () Ami. ^. 4: ■ ! I it I m' m '^r .1 346 I'YIIOXYLIC SPIRIT AND ITS COMPOUNDS. 6 Racemovinic acid C H** C) + 2 (C 1 1'' O^) + H O 7 Camphovinic acid C IP () + 2 (C" H^* O'') + H O These salts have, in compliance with the opinions entertained by the original discoverers of them, been described in the first part of this volume, while treating of compound acids. In reality, their true place is immediately after the acid ethers, of which they constitute a kind of complement. CHAPTER III. OF P Y II O X Y L I C SPIRIT AND ITS COMPOUNDS. mi nil Dumas informs us that this remarkable substance was discovered by Mr Philip Taylor, in 1812, but that he did not make it known to the public till 1 822, in a letter to the editors of the Philosophical Journal* Never having seen this communication of Mr Philip Taylor, I do not know the evidence which he has bro'ight forward in proof of his being the discoverer. IJut I have been myself in the habit of using it in lamps ever since 1816. And when I went to Glasgow, in 1817, I found that it was prepared for sale in that city, by Messrs Turnbull and Ramsay. It was, undoubtedly, therefore, well known in this country long before 1822, the date of Mr Taylor's communication. When wood is distilled for the purpose of obtaining acetic acid, the pyroxyiic spirit is formed, and found in the aqueous liquid which comes over. It is (Y'canted off to separate it from the tar which comes over at the b.me time. This aqueous liquid being subjected again to distillation, it is in the first tenth part of the product that we are to look for the pyroxyiic spirit. By repeated rectifications it is obtained in a state of considerable parity. The last rectifica- tions must be made over quick lime, partly to remove water, and partly some other im])urities. The quantity o" ammonia disengaged, when the lime is added, is considerable. This ammonia was in com- bination with acetic acid. Pyroxyiic spirit is pure when it does not become coloured by ex- posure to the air and light, when it mixes with water in all propor- tions without becoming muddy, and when it does not form a black precipitate when mixed with protonitrate of mercury, and has no action on paper stained with vegetable colours. The quantity of it contained in the liquid obtained by distilling wood, is about 1 per cent. Mr Kane, of Dublin, published an interesting set of experiments on pyroxyiic spirit, in 183^;.t He informs us that he had begun the examination of it before the appearance of Dumas' ])a]>er ; and I remember hearing a paper on the subject read by him, at the meeting of the British Scientific Asso«'iation at Dublin, in ISS.O. ' rhimic A|ii''iqiuV aiis Ait:=, v. 4: t Aim, tier rbui'inac'u , xix, lOl, Hiif til ^ VYIIOXYLIC Sl'IUIT AND ITS COMPOUNDS. 347 ) O dby irt of true titute iovcretl known iophical Philip forward lyself in I 1 went in that )ubtec\\y, c date of >tic acid, lid which ;ar which subjected Iduct that Atications rectifica- iter, and sengJ^ged, LS in com- led by ex- |ll propor- a black |(\ has no |ntity of it percent. Leriments luvd begun per; and im, at th^e in 1B3.J. He purified the spirit by saturating it with dry chloride of calcium. The saturated solution crystallizes in long shining six-sided tables. He distilled these crystals over the water-bath, as long as they yielded spirit, and then adding water, continued the distillation. It is colourless, very fluid, and has a peculiar smell, at once alcoholic and aromatic, and mixed with the o'lour of acetic ether. It boils by my trials at 150°. Dumas and Peligot state the boil- ing point to be 15 1 °'7,* under a pressure of 2l)*96 inches of mercury ; Macalr and Marcet, 150° ;t while Leopold Gmelin makes it as low as 137° ;$ and Kane found it 140°.§ The tension of its vapour at 570° is 3*27 inches of mercury. The specific gravity of the liquid at 68° is 0*798. So that in this respect it does not differ much from alcohol. The specific gravity of its vapour at the temperature of boiling water is 1*120, that of air being unity. It was analyzed by MM. Dr.mas and Peligot, and by Mr Kane, of Dublin, who obtained I D. &P. Carbon Hydrogen Oxygen 1 atom = 0*75 or per cent. 37*5 2 atoms =0-25 — — 12*5 1 atom =1-00 _ — 50-0 100*00 2-00 100 We might consider it as a compound of 1 atom carbo -hydrogen, and I atom water. But the analogy of ether renders it more likely that it is an oxide of dicarburettcd hydrogen. Dumas and Peligot found the specific gravity of the vapour of pyroxylic spirit to be 1*120, while Kane obtained 1*121, or almost exactly the same result. • Now, 1 volume cai'bon vapour weighs . 0*4166 2 volumes hydrogen gas weigh . 0*1388 ■| volume oxygen gas weighs . . 0'5555 1*1111 Hence, it is obvious that the vapour consists of 1 volume carbon, 2 volumes hydrogen, and half a volume oxygen, condensed into 1 volume. Pyroxylic spirit may be preserved without alteration in a vessel, though imperfectly corked. But when its vapour mixed with air * Ann. He Chim. et de Phys. Iviii. 10. f Bibliothequc Universelle, xxiv. 126. t Handbuch dcr Thcoret. Chiinie, ii. 344. § Ann. der Pharmacie, xix. 1G3. 11 Liebig obtained Carbon .... 54"20 Hydrogen . . ." 1 1 • 11 34-C9 Oxygen 100 \\x. u;i. But tlie spocitic ciavity was 0'804. Tiir siibstano^ analyzed was difl'crenf from pyrf>xylic spirit, Licl)i,s: uot it from L. Umeliii. Ann, dcr Pliarni. v, ;J'J. , ,■(' w K 348 PYJIOXYLIC SPiniT AND ITS COIMroiINDS. ' t E -I i .t ■r: ■iij " ' i' : V f I I i • I- >. \ I ;;i N is left in contact with sjjongy platinnni, nuicli licat is evolved, ami formic acid is formed. To make this experiment with ease, lot a glass cylindrical jar, o])en at both ends, be placed upon a large plate containing distilled water. Put 3 or 4 capsules, containing from 200 to 300 grains of spongy platinum within the jar, and also some pyroxylic spirit in a wine glass, and within the glass jar. By degrees the vapour of the pyroxylic spirit diffuses itself through the glass jar, and the reaction commences whenever a mixture of this vapour and air comes in con- tact with the spongy platinum. Abundance of vapours condense on the sides of the glass, which trickle down into the waler, and gives it an acid taste. If the pyroxylic spirit be renewed in proportion as it evaporates, the liijuid in a few days contains enough of acid to enable us to ascertain that it is impregnated with Ronnie acid. When alcohol is treated in the same way, acetic acid is formed. What happens in this case will be anderstood by inspecting the following formula' : — 2 atoms of pyroxylic sjjirit are C^ H* O^ 1 atom of formic acid . (*' H O'' Hence, to convert 2 atoms of pyroxylic spirit into 1 atom of formic acid, we must abstract 3 atoms of hydrogen, and add 1 atom of oxygen. The oxygen of the atmosplicre, by the intervention i)f the sponiiy ])latinum, converts 3 atoms of hydrogen into water, and adds 1 atom of oxygen. If we let the pyroxylic spirit fall, drop by drop, on the spongy platinum, it becomes incandescent, and the spirit burns, producing carbonic acid in great quantity. Chlorine acts upon pyroxylic spirit much less violently than upon alcohol. When it is poured into a ])hial of dry chlorine gas, hardly any heat is evolved, and the action is slow, even when assisted by the solar influence. Even when chlorine and pyroxylic spirit are agi- tated together, the action is very slow. It is necessary to distil the liquid a number of times in contact with chlorine. Two liquids are produced very different in their volatility. The least volatile com- bines with ammonia, and forms a crystallizable compoiuid. But Mr Kane found, that when dry chlorine gas and vajjour of pyroxylic spirit come in contact, an explosion takes pi ice. lie j)assed a current of chlorine through the s])irit to saturation. Much muriatic acid was formed. He obtained two liquids. The lightest was very acid. The other ..as thick, had nearly the specific gravity of sulphuric acid, had a sharp and biting taste, and reddened litnms, doubtless because not quite free from umriatic acid. It was ana- lyzed bv Mr Kane, who obtained Carbon 2I-,52 Hydrogen .... 1*5() Oxvgon .... l()-3r) ("hloviiic .... (i(i\57 (l(»-0() I'YKUXYI.U; SPlUir and its COMTwUNDS. 349 , anil il jar, jtilleil ins of t in a of the action in con- mse on I gives portion of aciil Ic acid. icd. ing tlie ,f formic atom of jn of tlie and adds ic sponoy Toducing han upon Ls, bardly .\ by the are agi- distil the quids are tile coui- ^^apour of lice. llt> In. ^Tucli Ic ligiitest tc gravity [)i\ litmus, 1 was ana- Froiu tlioso numbers we might deduce Llie following formula: — 2] atoms carbon = 2*0025 or per cent. 20'7o 1 atom hydrogen =0-1250 — — 1-25 1 atom oxygen =1-0000 — — 10-10 U atom chlorine =0-7500 — — G7-i)0 9-9375 100 But this formula is so unlikely to represent the true constitution of a body, that it would be wrong to adopt it without further investigation. Wiien pyroxylic spirit is distilled with a solution of chlorite of lime (or bleaching powder) a liquid is obtained, to which Dumas, who investigated its nature, has given the name of chloroform. It has been already described in a preceding Chapter. It was discovered about the same time by MM. Soubeiran* and Liebig,t by distilling a mixture of alcohol and solution of chlorite of lime. But Dumas assures us that its nature is the same, whether we employ alcohol or pyroxylic spirit.| Pyroxylic spirit dissolves j)otash and soda. The solutions arc similar to those of alcohol. Tiiey become brown-coloured wlicn exposed to the action of the atmosphere. When pyroxylic spirit, concentrated as much as possible, is brought in contact with barytes, it becomes hot, dissolves the base, and remains combined with it. To obtain the solution pure, we must add barytes in powder to absolute pyroxylic spirit, filter the solution, and evaporate in vacuo. A crystalline compound remains, composed of Barytes . . 70-5 or 1 atom = 9-5 Pyroxylic spirit 29-5 or 2 atoms = 4 100 13-5 When this compound is cautiously distilled, it furnishes a liquid similar to pyroxylic spirit ; then melts and yields an oily product. Finally, it blackens slightly, and the barytes is left in the state of a carbonate. When hot pyroxylic spirit is saturated with barytes, it deposits on cooling, silky needles, which speedily become brown when exposed to the air. Pyroxylic spirit dissolves salts almost like alcohol. It precipitates the sulphates from aqueous solutions. It dissolves chloride of cal- cium in abundance, and forms with it a crystallizable compound. It dissolves the resins, and as it is more volatile than alcohol, it answers ex(!eedingly well for making varnishes. It is not so good a solvent of very hydrogenous bodies as alcohol ; but it is an excel- lent solvent of bodies which contain nuich oxygen. When a mixture of 1 part of pyroxylic spirit, and 4 parts of concentrated sulphuric acid is distilled, v gas comes over, which possesses exactly the constitution of alcohol va])our. i| ;;i I, i „ I I f Ann. dc Cliiin. et de Pliye. xlviii. 1,'jl. f Ibi.J. xlix. \A^. % l'^'*!- '^''''- ^^' T fl ! 350 rvnoxYLic spinrr and its compounds. E) ! fji I 1.1 It has an ethereal smell, is totally soluble in water, and burns with a flame similar to that of alcohol. At Hrst it is mixed with carbonic acid gas, and sulphurous acid gas ; but if it be left for 24 hours in contact with fragments of potash, these impurities are dissolved. The specific gravity of this gas, as determined by MM. Dumas and Peligot, is 1*61 7. A volume of it requires for complete combustion 3 volumes of oxygen gas, and forms 2 volumes of carbonic acid. Hence it contains 2 volumes carbon . J0*8333 7 condensed into 2 volumes hydrogen 0-1388 3 1 volume. 0-9722 If we subtract 0-9722 from l-fil7, the specific gravity of the gas, the remainder 0'G248 is almost exactly equal to the sjjecific gravity of a volume of vapour of water, namely, 0-625. Hence it is obvious that this vapour is a compound of 1 volume oleliant gas . 0-9722 I volume vapour of water 0-(i25 1-5972 condensed into 1 volume ; vbieh gives preciscjly the elements that enter into the constitution of alcohol. The very same thing takes place in this distillation as when we heat a mixture of alcohol and sulphuric acid. One half the water is abstracted relative to the other ingredienf, the carbohydrogen. When* alcohol is used, the deutocarbohydrogon, or olefiant gas, is converted into ether ; but when pyroxylic spirit is used, the com- ])ound is C'^ IP O, or it contains an atom oi olefiant gas less than ether. This is the same thing in both cases as abstracting one half of the water which the spirit contained. But in reality Alcohol is . . C* H^ O + H O While this gas is . C^ H'^ + II O We see the reason why its properties are so dilierent from those of alcohol. Action of the hyihacids on pyroxylic spirit. When j)yroxylic sj)irit is made to act on the hydracids, a set of compounds is formed very analogous to the ethers wliic^h the same acids form with alcoiiol. These bodies have been examined by Dumas and Peligot, who consider them as compounds of the hydracid employed and methylene, which in their opinion acts the part of a base.* * Dumas and Peligot have given the name of methylene to what they consider to be the base of |)yroxylic spirit, and wliieh lliey nuikt C- H-, and j)yroxyhc spirit tiiey maice C- H'^ + ^ O. Hut the subject will be much simplified if wi; ap|)ly Liei)ig's tlieory of ethers to j)yroxylie spirit with the reciuisitc modification. The base of pyroxylic si)irit will be C- H', and j)yroxylic spirit will be C" IP (). This base has not yet been insulated, but the following sails are obviously tlu! chloride and iodide of C- IF, which we may, al'ier Dumas and I'cligot, denoininutc methylene. It follows from the ex|ieriments of Dinn,\;- and I'eliirot, tliiil pyroxylic spirit is Til, ia I'YUOXVLIC SIMllU AND ITS COMPOUNDS. 351 urns with u- 24 n {irc MM. ics of ntains e gas, irravity jbvlous nts that when we lie water ^drogcn. ; iias, is he cora- ess than iiig one reality I those of |)yroxylic Is formed Irui with Peligot, lyed and ly consiJcr I pyroxylic tlicil if "'• jJitit:ation. C- H^ O. lioiisly till.' leiiomiii'i-'l<; lii' spirit is) 1. ('hloride or muriate of methylene. Tliia compound, analogous to nnn-iatic etlier, is most conveniently obtained by heating a mix- ture of two parts of common salt, one part of pyroxylic spirit, and three parts of concentrated sulphurii acid. By the application of a gentle heat, a gas is obtained, which may be collected over water, and which is pure muriate of methylene. This gas retains its elasticity though cooled down to zero, or even a degree lower. It is colourless, has an ethereal odour, and a sweet taste. It burns with a flame, white in the middle, and green round the edges. Water dissolves 2*8 times its bulk of it, at the temperarure of 61°, and when the barometer stands at 30 ii>ches. It does not alter vegetable blues, nor does it precipitate nitrate of silver. When detonated with an excess of oxyg( i gas, it is decom- posed, and the products are water, carbonic acid, muriatic acid, and some traces of chlorine. The water formed is sufficient to condense the muriatic acid disengaged. Each volume of gas requires I^ volume of oxygen, and produces a volume of carbonic acid gas. Hence it is obvious that every volume of the gas contains a volume of carbon vapour, and a volume of hydrogen gas, united into a vo- lume of carbohydrogen. The specific gravity of gaseous chloride of methylene is . ... 1'7310 That of carbohydrogen . . 4861 1-2449 Now, the specific gravity of muriatic acid gas is 1*28472, almost identical with this residue. Hence there can be no doubt that the chloride of methylene is composed of C IP Chi. C H- (). Ferliiips it would be bettor to double these numbers, and to considor it as C- H' O + H O. It would then bear the sjine relation to the base which these elicinists liave distinfjuished by the name of methylene, that alcohol does to ether. On that view we mif^'ht consider the unknown basis of |)yroxylic spirit to be C* H'', or methyl. Of this pyroxylic s])irit is tiio hydratcd oxide. The other compounds, by Dumas and Pciigot's analysis, are Chloride or nmriate of methylene . C' H' + Cid- • Iodide or hydriodato . . . C- H'' -|- lod Fluoride of fluate . . . . C'^ H-' + Fl The salts of methylene, analogous to the acid ethers, are the following : — Sulphate Nitrate Oxalate Acetate Formate Benzoatc Mucate Oxy chlorocarbon a te Chlorocyanate Cyanate C^ H ' O + S 03 C- H^ O C- H' O + C^ ()■* Az 0=* C H' O' C2 H 03 , C-' W O C- H^ O C- H^ O + C" W 0» iZ' H' O + C8 H^ O' . C^ W + C- Chi 0» . C^ H' O + (C^ Az) Chi , C- H" O 4- '2 (C- Az O) + 3 (H O) The acidulous methylene salts, similar to althionic acid, and the other compound ethereal salts, are the following : — Sulphomethylic acid . C* H^ O + 2 (S O^) Tartromethvlic . . C- H'' + 2 (C H'^ O'') Racemometin lie . . C- H^ O + 2 (C^ H^ O") ill lit ^' ; T^ ii ' ;i.V2 I'YK(jXYLIc si'iKiT \Ni) ITS ' t):'.ii>')ii :; j;.s. ; M' H I It is tliorfforc jnToxylic spirit, with an iitom of clilorino l^.^titute acid. When the ebullition thus ])rodure(l Is at an end, the rest of the phosphorus is added, and the whole agitated. By and by heat nnist be applied, otherwise the eH'ervescence would cease altogether. The distillation is continued as long as an ethereal li(piid continues to ])ass. The residue ii'. the retort contains phosphorous acid, phospho- methylic acid, and phosphorus. It is quite tlcprived of colour. The liipiid in the receiver is composed of pyroxylie acid and iodide of methylene. When water is added to the mixtiu'c the iodide im- mediately separates. The (piantity obtained nccirly equals the weight of the iodine employed. It is still very impure. To obtain it in a state of purity, we must distil it over the water-bath with chloride of calcium, and litharge in great excess. It is a colourless liquid, weakly cond)ustible, burning only when T\ut tisio the flame of a lamj), and then giving out violet vapours in ..icat abundance. Its specific gravity at 71" is 2*2.'i7. It boils Mh«',n heated to between 100° and 120°. I'umas and Peligot analyzed it by means of oxide of copper, and obtained Carbon 8'<)2 or 2 atoms = Iv'i or per cent. 8'.5l Hydrogen 2-23 or 3 atoms = 0-375 — — 2-12 Iodine 88-85 or 1 atom = 15*75 — — 8i)-37 100-00 17-f! \olnmc3 of the gas. Its spocitic gravity was 1*180. It was composed of ne • 1 1 volume m 1 volume ' united together, and condense 1 atom fluoric, acid I atom niethylene me ; or it is composed of 1-25 1-875 .3-125 So that its atomic weight is 3-125. Action of the oxacids on pijroxylic spirit. When the oxacids are made to act upon pyroxylic spirit, two different compounds are formed ; one corresponding with the ethers formed by means of the same acids and alcohol, and which are in reality neutral salts ; an- other constituting acid salts, and corresponding with althionic and other similar acids. The former, which are perfectly neutral, are obtained more easily than the corresponding alcohol ethers. They all contain an atom of C IP C), united to an atom of the acid. They are more volatile, and more stable than the corresponding alcoholic compounds. 1 . Sulphate of methylene. No compound made from alcohol cor- responding to this is known. The simplest method of obtaining it is to distil one part of pyroxylic spirit with eight or ten parts of con- centrated sulphuric acid. A-. soon as ebullition commences there passes into the receiver an oily liquid, mixed with a methylic liquor. This oily Tupud becomes gradually very abundant, and when the distillation is finished, its quantity is at least equal to that of the pyroxylic spirit employed. The acid mixture should be distilled slowly, but the boiling should be constantly kept up. This oily licpiid being separated by decantatiou from the aqueous rKjUor, is first agitated with a little water, and then with a little chlo- ride of calcium. It is then rectified several times successively over caustic barytes in a very fine powder. Finally it is proper to leave it for some time in the vacuum of an air pump with concentrated sulphuric acid and potash. The object of these processes is to Irvor e ither Ann. do Cliim. ot dc? Plivn. Ixi. 19:3. 2 A IMAGE EVALUATION TEST TARGET (MT-3) %^ LO I.I 1.25 ■ 50 21 |2.5 ■^ 1^ 12.2 £f 134 ■ WU4. 1^ U , ,A 1 ^ < >/ i^ 1 w •'I Photographic Sciences Corporation 23 WEST MAIN STREET WEBSTER, N.Y. 14580 (716) 873-4503 v.. \° ^ i'^: t:,^l 304 PYROXYLIC SPIRIT AND ITS COMPOUNDS. ■"!' separate some sulphuric acid, sulphurous acid, water, and pyroxylic spirit, which the liquid may contain. When pure it is colourless, has an alliacious smell, and a specific gravity of 1'324 at the temperature of 71°^. It boils at the tem- perature of 370°, under a pressure of thirty inches of mercury. Dumas and Peligot subjected it to analysis by means of oxide of copper, and found 100 parts of it to yield Carbon .... 19-03 Hydrogen .... 4*78 Now, these two numbers are to each other in the proportion of 2 atoms carbon . . . = 1*5 3 atoms hydrogen . . . = 0-375 If we consider it as composed of 2 atoms carbon =1*5 or per cent. 19'04 3 atoms hydrogen = 0*375 — — 4*76 1 atom oxygen = 1-000 — — 12-70 1 atom sulphuric acid = 5-000 — — 63-50 7-875 100-00 Then it consists obviously of C2 H' O + S 03 If C^ H' O be methylene, it is a sulphate of methylene. Dumas and Peligot attempted to determine the density of the vapour of sulphate of methylene. They obtained as a result 4-565. But they do not consider this number as deserving of confidence. There can be little doubt that the true specific gravity of the vapour of this substance is 4-3750, for it obviously consists of 1 volume methylene vapour . 1*5972 1 volume sulphuric acid . . 2-7777 4-3750 The sulphate of methylene may not only be distilled over without alteration, but it may be heated to 392° without undergoing any decomposition. It is slowly decomposed by cold water, and rapidly by boiling water. The last acts w ith violence, evolving much heat, and the sulphate disappears altogether, without producing any new oil. Sulphomethylic acid is formed, and pyroxylic spirit is regenerated. Caustic barytes has no action on it. Hydrate of barytes, and the hydrated alkalies, or their aqueous solutions, decompose it with great facility. Thus, solution of potash converts it, with much heat, into sulphoraethylate of potash and pyroxylic spirit. By means of sulphate of methylene all the other compounds of methylene and acids may be obtained. Thus, when heated with fused common salt, sulphate of potash is formed, and muriate of methylene is disengaged in the gaseous form. When heated with fluoride of potassium, hydrofluate of methylene is disengaged in the gaseous state. When heated with cyanodide of mercury, or of potassium, sulphate of potash, or sulphate of mercury is formed, and cyanodide of methylene may be collected in the liquid form. ^^■Y^mfM^ PYROXVLIC SPIRIT AND ITS COMPOUNDS. 355 >xyVic )ecific I teni- ae of of ty of the It 4-565. infidence. le vapour ;r without roing any id rapidly I heat, and y new oil. renerated. rytes, and 3se it with nuchheat, apounds of eated with aiuriate of leated with mgaged in cury, or of is formed, iquid form. When it is distilled with benzoate of potash, we obtain benzoate of methylene ; and so on. When 2 parts of pyroxylic spirit, 2 parts of binoxide of man- ganese, and 3 parts of sulphuric acid, diluted with their own weight of water, are mixed, a violent effervo«icence takes place, and a great deal of formic acid is evolved. The otlier products from the distil- lation of this mixturehavebeen examined with great care by Mr Kane.* 2. Nitrate of methylene. This compound was obtained by Dumas and Peligot by putting into a retort 50 parts of nitre, 100 parts of sulphuric acid, and 50 parts of pyroxylic spirit. The retort should be large, and connected with a large receiver communicating with a bottle containing salt water, and surrounded with a refrigerating mixture, and from this should pass a tube capable of conducting the gas formed into the chimney. It is only necessary to apply heat at the commencement of the process. Afterwards it goes on of its own accord. When the process is finished, the liquid in the receiver is poured into the bottle. In this way we obtain at the bottom of the bottle a colourless layer of the new compound. It must be separated by decantation and purified by distilling it off a mixture of massicot and chloride of calcium. Thus prepared it is impure. If it be heated to the temperature of 140°, it boils and gives off a substance having a decided odour of hydrocyanic acid. The temperature gradually rises to 151°. What comes over at that temperature is considered by Dumas and Peligot to be in as pure a state as they could procure it. It is a colourless liquid, having a specific gravity of 1*182 at the tem- perature of 7 1 °. It boils at 1 5 1 °, giving out a weak ethereal odour. It is perfectly neutral, and burns with a lively yellow flame. When the vapour is heated to about 302°, it detonates with great violence, so as to produce dangerous results if the quantity be considerable. Dumas and Peligot analyzed it by means of oxiae of copper. The result of 6 analyses made in this way led to the conclusion that it was composed of ' 2 atoms carbon . . . = 1*5 3 atoms hydrogen . . . = 0*375 1 atom azote . . . = 1*75 6 atoms oxygen . . . = 6*00 9-625 This is equivalent to C^ H» O + N 0». They found the specific gravity of the vapour of nitrate of me- thylene to be 2-640. Now, 1 volume methylene . . =1*5972 1 volume nitric acid vapour . = 3*7500 2)5*3472 2*6736 'I. i ^1! ♦ Annalender Pharmacie, xix. 175. 356 PYROXYHC SPIRIT AND ITS COMPOUNDS. This result agrees as nearly as could be expected with the specific gravity of the vapour fouud. When pyroxyhc spirit is treated with nitric acid and silver, in the well known method for obtaining detonating silver, no violent action takes place. Nitrate of methylene, distils over ; and towards the end of the process, if the nitric acid was strong, oxalate of silver is deposited.* The same thing happens when we substitute mercury for silver. 3. Oxalate of methylene. The method of obtaining this com- pound, is to distil a mixture of equal parts sulphuric acid, oxalic acid, and pyroxylic spirit. There passes over into the receiver a spirituous liquor which, when exposed to the air, speedily evaporates, leaving a residue crystallized in fine rhomboid plates. As the dis- tillation proceeds, the quantity of this crystalline matter increases. At last the whole liquors that pass over assume a solid consistency. When the distillation is terminated, if we allow the retort to cool, and add as much pyroxylic spirit as at first, and distil a second time, we obtain the same product. The crystals from these two distillations being well drained on a filter, are to be melted over an oil-bath to dry them, and distilled over massicot to free them from oxalic acid. The product thus obtained is pure oxalate of methylene. It is colourless, and has a smell similar to oxalic ether. It melts at 124", and boils at 322°, under a pressure of 30 inches of mer- cury. It dissolves in cold water, and speedily undergoes decompo- sition when thus dissolved, especially if it be heated, being converted into oxalic acid and pyroxylic spirit. It is soluble in alcohol and pyroxylic spirit, and more soluble when these liquids are hot than when cold. The alkaline hydrates destroy it napidly, forming oxalates and pyroxylic spirit. But anhydrous bases, or at least oxide of lead, do not alter it ; anhydrous ammonia converts it into a new substance. Liquid ammonia con- verts it into oxamide. Dumas and Peligot analyzed it by means of oxide of copper, and obtained for its constituents Carbon 41-08 Hydrogen .... 6*28 Oxygen .... 53*64 These numbers approach 4 atoms carbon 3 atoms hydrogen 4 atoms ciygen 100-00 = 3 or per cent. 40-68 = 0-375 — — 5-08 = 4 — — 54-24 100-00 7-375 This is equivalent to C" H^ O + C^ O^. 4. Acetate of methylene. This compound may be obtained in • Dumas and Peligot, Ann. de Chim. ct de Phys. xi. 193. But it PYnOXYLTC SPiniT AND ITS COMPOl'NDS. 357 fie ICl r, in olent mrds ite of titute coin- oxalic liver a jrates, tie dis- reases. steticy. ;o cool, second ed on a distilled xct thus It melts of mer- lecompo- onverted soluble hydrates rit. But nbydrous onia con- jper, and abundance by distilling a mixture of 2 parts pyroxylic spirit, 1 part crystalli;:able acetic acid, and 1 part sulpburic acid of commerce. The product obtained is ])ut in contact with a solution of chloride of calcium, which separates an abundant ethereal liqiiid, containing much acetate of methylene. As it still contains some sulphurous acid, and some pyroxylic spirit, it is agitated with quick lime, and then left to digest over chloride of calcium for 24 hours, which absorbs the pyroxylic spirit. It is a colourless ethereal liquid, having an agreeable odour, analogous to that of acetic ether. It boils at 136°^ under a pressure of 30 inches of mercury. Its specific gravity is 0*919 at the temperature of 71°^. Its constituents, determined by the analysis of Dumas and Ptjligot, are Carbon 49*2 or 6 atoms = 4*5 or per cent. 48'65 Hydrogen 8*3 or 6 atoms = 0*75 — — 8*11 Oxygen 42*5 or 4 atoms = 4*00 — — 43*24 100*0 9*25 100*00 This is equivalent to C=» H' O + C* H» O'. The specific gravity of the vapour of acetate of methylene is 2*563, as determined by Dumas and Peligot. Now, the specific gravity of 1 volume methylene vapour . := 1*5972 1 volume acetic acid vapour . = 3*5416 2J5TSSS 2*5694 M. Laurent passed a current of chlorine gas slowly through acetate of methylene, and then distilled the liquid, leaving out the first portions which contained two oils. He obtained a colourless liquid, heavier than water, insoluble in water, but soluble in ether and alcohol. It boiled at 293°, and could be distilled over unaltered. Liquid potash attacked it, the liquid became brown, and a vapour was disengaged having a strong smell and a sweet taste. Perhaps, also, formate of potash was formed. The liquid was analyzed by Laurent, and found composed of Carbon 20*25 Hydrogen . . . . 1*71 Chlorine . . . . 63*09 Oxygen .... 14*95 100*00 From these numbers (which are only distant approximations) he deduces the following formula : — 6 atoms carbon = 4*5 3 atoms hydrogen = 0*375 3 atoms chlorine = 13*5 2 atoms oxygen = 2*0 or per cent. 22*09 - — 1*84 - _ 66*25 - — 9*82 jtained in 20*375 But it would be unsafe to draw deductions from this analysis.* * Ann. de Chim. ct dc Phys. Ixiii. 382. 358 PYUOXYLIC SPlllIT AND ITS COMPOUNDS. 5. Formate of methylene. Dumas and Peligot obtained this com'- pound by distilling in a retort a mixture of about equal parts of sulphate of methylene and dry formate of soda. When the mixture is gently heated, the reaction commences, and the temperature becomes speedily high enough, to allow the process to go on without the farther application of artificial heat. A very volatile liquid passes into the receiver, which must be kept cool. This liquid is formate of methylene nearly in a state of purity. To make it quite pure, it should be distilled first over a fresh quantity of formate of soda, and afterward alone in a dry retort over a water-bath. Pure formate of methylene thus obtained is very volatile, lighter than water and has an agreeable ethereal smell. It was analyzed by Dumas and Peligot by means of oxide of copper, and found to be composed of Carbon 40*66 or 4 atoms = 3 or per cent. 40 Hydrogen 6*83 or 4 atoms = 0*5 — — 6*7 Oxygen 52*50 or 4 atoms =4 — — 53*3 7-5 100-0 100*00 Equivalent to C» H» 0-f C« H O' The specific gravity of vapour of formate of methylene, as deter- mined by Dumas and Peligot, is 2*084. Now 1 volume methylene vapour . = 1*5772 1 volume vapour of formic acid . =2*5672 2)4*1644 2*0822* 6. Benzoate of methylene. This compound may be obtained by distilling a mixture of 2 parts of benzoic acid, 2 parts of sulphuric acid, and 1 part of pyroxylic spirit, and mixing the liquid which passes over into the receiver with water. The ethereal portion separates. After washing it two or three times with water, let it be agitated with chloride of calcium, decanted off, and distilled over dry massicot. Finally, let it be boiled till its point of ebullition becomes fixed. It ought to be 388°^. Benzoate of methylene is oily, colourless, and has an agreeable balsamic odour. Its specific gravity is 1 * 1 at 62°^. It is insoluble in water, but it dissolves readily in pyroxylic spirit, alcohol, and ether. Its constituents, determined by the analysis of Dumas and Peligot, arc Carbon 71*4 or 16 atoms = 12 or per cent. 70*59 Hydrogen 6*2 or 8 atoms =1 — — 5*88 Oxygen 22*4 or 4 atoms =4 — — 23*53 100*0 17 100*00 Now these atOxnic numbers mwy bo nronpod as follows : — * Aim, dc Chim. ct de Phvs. Ixiii. 48. PVROXYLIC SPIRIT AND ITS COMPOUNDS. 359 com- rts of ixture rature ithout liquid ^uid is L fresh ■ retort lighter oaiyzed )und to I atom nietliylenu 1 atom heiiitoic acid = C» W O as deter- tained by sulphuric lid which portion er, let it lied over ebullition 1 laoreeable Isoluble in lind ether. jligot, arc )9 >3 )0 Thus its constitution is precisely similar to that of the other salts of methylene which have been already described. Dumas and Peligot found that beuzoate of methylene may be obtained by distilling a mixture of dry benzoate of soda and neutral sulphate of methylene. The specific gravity of the vapour of benzoate of methylene, as determined by Dumas and Peligot, is 4*7 17. Now 1 volume methylene gas . = 1*5772 1 volume benzoic acid vapour = 7*8475 2)9*4247 4*7123 7. Mucate of methylene. This compound was first formed in 1836, by M. Malagutti.* The process for preparing it is precisely the same as that for preparing mucic ether, only substituting pyroxylic spirit for alcohol. It is solid, crystallized, colourless, fixed, and insipid. It may be ob- tained in crystals, either from alcohol or water, but the crystals are not so distinctly shaped as those of mucic ether. When viewedwith a micro- scope they appear to be rectangular prisms with bevelled summits. When heated the mucate of methylene undergoes decomposition before it melts. Decomposition begins at the temperature of 325°^ and shows itself by the evolution of a black oily matter ; at 345*'*2 it assumes the form of a black liquid, which swells and gives out carburetted hydrogen. It is very little soluble in boiling alcohol, one part requiring 200 of alcohol of 0*814 to dissolve it. When the solution cools the mucate almost all falls under the form of a crystalline powder. It is very soluble in boiling water ; but partly precipitates as the solution cools. The specific gravity of the crystals from alcohol is 1*48, that of those from water 1*53. M. Malagutti analyzed this mucate of methylene, and obtained Carbon 40* IG or 8 atoms = G or per cent. 40*34 Hydrogen 5*91 or 7 atoms = 0*875 — — 5*88 Oxygen 53*93 or 8 atoms =8*0 — — 53*78 lOO-OOf 14*875 100*00 Equivalent to C^ W O + C« H* 0^ Thus it agrees jn its compo- sitions with all the preceding compounds. 8. Oocy-chloro-carbonate of methylene. When pyroxylic spirit is introduced to a glass vessel filled with chloro-carbonic acid the tem- perature rises suddenly, and the reaction is terminated in a very sliort time. Muriatic acid is formed, and chloro-carbonate of * Ann. de Chim. ct dc Phys. Ixiii. 94. f Ibid. y. 295. 360 PYROXYLIC SPIRIT AND ITS COMPOUNDS. ^ ril } t, ! I i t I i I j methylene, which separates under the form of a heavy oil when the pyroxylic spirit employed contains some water. It is easily sepa- rated from the water by decantation. It must then be rectified by distilling it by the vapour-bath over a great excess of chloride of calcium and massicot. Should it be suspected of still retaining any pyroxylic spirit, it may be digested without heat over fragments of chloride of calcium. Thus purified it is a colourless liquid, very fluid, has a penetrat- ing odour, is very volatile, and heavier than water. It burns with a green flame. From the analysis of Dumas and Peligot, it follows that the con- stituents of this chloro-carbonate are Carbon 25'57 or 4 atoms =3 or per cent. Hydrogen 3*46 or 3 atoms = 0*375 — — Chlorine 37*12 or 1 atom = 4*5 — — Oxygen 33*85 or 4 atoms =4*0 — — 25*26 3-16 37*90 33*68 10000 10000 11-875 Equivalent to C» H^ O + (C» O^) Chi An atom of the water which enters into the constitution of pyroxy- lic spirit is decomposed, its hydrogen uniting to the chlorine of the chloro-carbonic acid, and converting it into muriatic acid, while the oxygen takes the place of that chlorine ; so that 2 atoms of chloro-carbonic acid, C O^ Chi", become C* O' Chi, or an atom of oxychloro-carbonic acid.* 9. Chlorocyanate of methylene. This compound was discovered in 1837 by M. Aime, who obtained it by passing a current of chlorine through a solution of cyanodide of mercury in pyroxylic spirit,! and washing the liquid that distilled over in water. Its specific gravity is 1*25. It boils at a heat under 122". It burns with a red flame, green round the edges. Ammonia decom- poses it immediately, and water in a few days. It is composed of 1 atom chloride of cyanogen . C^ Az Ch 1 atom methylene . . . C* H^ O 1 0. Cyanate of methylene. This compound was formed in Liebig's laboratory, examined and analyzed by Mr Richardson in 1837. It was obtained by passing liquid cyanic acid into pyroxylic spirit. The cyanate of methylene was deposited in the state of a white crystalline powder. Its characters and composition are stated by Mr Richardson to be the same as those of cyanic ether. It must then be C* H^ O + 2(C> Az 0) + 3(H O). M. Laurent has formed elaidate of methelyne, raargarate of methylene, and oleate of methylene, by processes similar to what has already been described. For the characters of these com- pounds I refer the reader to Laurent's paper.t Acid wmponnds of methylene. The first of these formed by * Ann. (le Cliini. ct He Phys. Ixiii. TrJ. t ll)itl- Ixiv. 222, j Ibid. Ixv. 206. '•--vuc ,P,„,„ .,„ „^ ^„,,_,^^^__^_ Duma, and Pe,i„„( ,. , "' c„„„„„«„,. ^^^ melhylic acid if- fl "»™ ■»■> iaSlL 1. „ , ■luce the proper reaS .t ' ,^''^'" l"*"' "a evolvert K ! ^"'"'^ a state of f„s5„„ ,pV°"; "'5 oxalate of methvW '.r' '" P'o- -\ 'ft a X™- cryst:fc''S?''"%S °s 1,T" "kohol andalloweSC J^ , '::^% ^-- «d t 'Sr ''-r'srirf-"S:!^reor-^^^^^^^^ Carbon "^ ' Hydrogen . * ' * 34-47 Azote .' * • • 5-06 Oxygen .' ' * • 13-90 46-57 These proportions give the following atom.V ^ 6 atoms carbon - 4.^ ^"'"'^ constituents ;^ f atoms hydrogen = O'62'S °'' ^^'' ''^"*- ^^'-^^ 1 atom azote :- 2-75 ~~ ~~ ^'^^ t> atoms oxygen =6-00 ~" "~ ■3°59 — — 4d-6l These numbers are resolvable intf'' ; atom oxalic acid pa ^3 I atom methylene ; g §' ^3 362 ACETONE. Thus wc see that the oxamcthylune is a compound of 1 atom oxalate of methylene . 7*375 1 atom oxamide . . . 5 '6 ^ CHAPTER IV. OF ACETONE. 21-875' I ?iil1 This is the name by which the pyro-acetic spirit of Chenevix is distinguished by modern chemists. It appears n-om a quotation of Proust, that acetone was first observed by Beccher. He obtained it by distilling acetate of lead, an(^ considered it as alcohol regenerated.! Proust himself had ob tned it, and he notices some of its most remarkable properties^ in ais remarks on Fourcroy's Systeme des connoissances Chimiqiiesy which were published in 1802. He mentions also that it had not been overlooked by Baum6 ; and that Bernard Pluvinet, in his dissertation defermentatione spirituosa et acetosa, had given a detailed account of its properties. It was obtained by Trommsdorf in 1805, by distilling acetate of soda, and this chemist described its properties at considerable length. § But Derosne was probably the modem chemist who first drew the attention of men of science to it. He obtained it during the distillation of verdigris in 1807, and determined its most remark- able properties. II Chenevix examined it again in 1809, determined the proportion of it furnished by the different acetates, and ascer- tained almost all its remarkable properties.^ Nothing farther was added to our knowledge of it till 1823, when it was subjected to a chemical analysis by MM. Macaire and Marcet,** in order to determine its chemical constitution ; but as these gentlemen give us no means of judging of the purity of the liquid which they subjected to analysis, the value of their experi- ments is thereby much diminished. Another analysis of it was made by Matteucci in 1831, ft and in 1832 it was examined and analyzed successively by LiebiglJ and Dumasf§§ Acetone is usually obtained by distilling acetate of lime. Thus *" Ann. de China, et de Phys. Ixi. 60. f Unde contingit quod si spiritus aceti cum plumbo in concluso vase distilletur, noil amplius spiritus accti, sed rursus spiritus vini ardens in lucem prodcat depo- sita priori larvu saliuu medianteque aceti spiritus vocabatur. X Jour, de Phys. Ivi. W8. § Gehlen's Jour. v. 578. II Ann. de Chim. Ixiii. 267. f Ibid. Ixix. 5. ** Bibliotheque Universelle, Oct. 1823. Annals of Philosophy (Second Series), viii. 71. ft Ann. de Chim. et de Phys. xlvi. 429. Jf Ibid. xlix. 195. Thd Liebifl CarboJ HydroJ Oxyge §§ Ibid. p. 208. t Ch end ACETONE. 363 8 first f lead, If had lertiest miques, nad not in his detailed •etate of iiderable vho first t during remark- tennined (1 ascer- ill 1823, caire and but as of the ir experi- was made analyzed ty Thus EC distilletur, rodeat Uejio- 78. cond Scries), Ibid. p. 20e. prepared, it requires to be rectified repeatedly over dry chloride of calcium over a water-batb, till its point of ebullition becomes steady. It is a colourlesa liquid, very fluid, and has a peculiar aromatic odour. Its specific gravity, when pure, is 0*792, as determined by Liebig* and l)uma3.t 1 he following table exhibits the specific gravity of this liquid, as obtained by the ditferent experimenters : — Deroane 0*71) Proust 0'88 Chenevix .... 0*78 Trommsdorf . . . . 0'75 L. Gmelin .... 0-822 J. Liebig .... 0-7921 at 640^ When pure it boils, according to Liebig, at 132° ; according to Dumas, at 133°.$ The density of its vapour, as determined by Dumas, is 2*019. Soluble in all proportions in water, alcohol, and ether — takes fire readily, and, like ether, gives out much light when burning — not altered by exposure to the uir, provided it be not allowed to fly ofl' in vapour — not altered by alkalies — has no action on chloride 01 calcium. When distilled with chlorite of lime, it forms chloroform. When chlorine gas is passed into acetone, the liquid becomes hot, much muriatic acid is formed, and the liquid assumes a green- ish-yellow colour. But the reaction soon ceases, unless the liquid be kept boiling-hot during the passing of the chlorine gas through it. When mixed with sulphuric acid, an oily liquor separates, which may be decanted ofl^, and rectified over quick lime. It has an amber colour, is insoluble in water, has a peculiar penetrating smell, and a specific gravity of 1*33. According to Dumas, its constitution may be represented thus : — 3 atoms carbon = 2*25 or per cent. 28*125 2 atoms hydrogen =0*25 — — 3*125 1 atom chlorine = 4*5 — — 50*25 1 atom oxygen =1 — — 12'5 8 100*0 The constituents of acetone, as determined by the analysis of Liebig and Dumas, are as follows : — Carbon Hydrogen Oxygen or 3 atoms or 3 atoms or I atom 2*25 or per cent. 62*07 0*375 — — 10*34 1 _ — 27*59 3*625 100 * Ann. de Chim. et de Phys. xliy. 196. f Triiilc de Cliimic appUquee aux Arts, v. 180. t Chenevix states the boiling point to be 138", while L. Gmelin makes it 133"!. II 3C4 ACBTONB. Now, if from an atom of acetic acid we Buhstruct an atom of carbonic acid C* C w o» Tlio remainder will be . . . C IP ( ) which is e((uivahnit to the constituents of an atom of acetone. I lenco acetone seems to be acetic acid, minus an atom of carbonic acid. If wo multiply the constituents of acetone, as above determined, by 4, we get C'» H'" O* Now these (juantities may bo resolved into 1 atom acetic acid . . C* IF O' 1 atom water . . . HO 1 atom octo-carbohydrogen C H* QVi H>a O* This is the view of the constitution of acetone, taken by Dumas. But I consider it as very unlikely to be correct. The specific gra- vity of the vapour of acetone was found by Dumas to be 2'OIU. Now, the specific gravity of 3 volumes carbon is . . 1*25 3 volumes hydrogen . . 0*2083 ^ volume oxygen . . . 0*5555 2*0138 Were we to adopt Dumas' opinion, it would be necessary to con- sider the vapour of acetone to be composed of 1 volume vapour of acetic acid = 3*5416 1 volume octo-carbohydrogen = 3*8888 I volume vapour of water = 0*()250 4)8*0555 2*014 united together and expanded into 4 volumes. But this is an alteration of bulk that has nowhere hitherto been observed in gas- eous combinations. Acetone resembles ether in its mode of burning. But as it unites in all proportions with water, it must rather be considered as a species of alcohol than of ether. M. Fremy discovered that when 1 part of sugar is intimately mixed with 8 parts of unslacked lime, and distilled, the product con- sists of two liquids, one of which is acetone, and to the other he has given the name of metacetone* The metacetone, when purified, is a colourless liquid, which boils at 183°. It is insoluble in water ; but soluble in alcohol and ether, and has an agreeable smell. The purification of it is at- * Ann. de Chim, ct de Phys. lix. 5. MRSITK. 365 jno. onic ncd, lumas. ic gra^ 2-019. r to conr- tondcd with considerable difficulty. M. Fromy nnaiyzud it, and obtained Corbon 72-37 or (I atoms = 4-5 or per cent. 73-47 Hydrogen 10-15 or 5 atoms =:0-()25 — — 10-20 Oxygen 17-48 or 1 atom =1 _ ^ l()-33 100 (M25 100 5| atoms carbon would come nearer the analysis than it atoms. Now sugar is a compound of C* H" O", and *^ 3 atoms acetone are . C» H" 0» 3 atoms carbonic acid . C O* 2 atoms water . . IV O" Cia H" 0>' Thus we see, that an atom of sugar is resolvable into 3 atoms ace- tone, 3 atoms carbonic acid, and 2 atoms water. The carbonic acid remains in combination with the lime. To perceive how the metacetono is formed, wc have 2 atoms sugar . . = C" H" O" 3 atoms metacetone 6 atoms carbonic acid 7 atoms water C" H" O" So that 2 atoms sugar must be resolved into 3 atoms metacetone, 6 atoms carbonic acid, and 7 atoms water. _. CIS H'» 0» = c« 0»a ^ W 0^ n CHAPTER V. OF M ESITE. jiis is an I This substance was discovered by Reichenbach among the pro- In gas- I ducts of the distillation of wood, and the account of it published in the year 1834.* It was obtained in the following way : — Eleven \ it unites I hunared pounds of tar from beechwood were distilled in an iron red as a | still by a very low heat. There came over at first a light-yellow oil. This was followed by an acid aqueous liquor. These two pro- ^timately I ducts came over together or separately, according as the heat luct con- I was higher or lower. When about 4| imperial gallons had been [other be I distilled over, the product was neutralized by the addition of dry I carbonate of potash, of which an unexpectedly large quantity was lich boils I requisite. In consequence of this saturation, a considerable quan- jbol and I tity of oil separated from the watery liquid. The whole liquid was it is at- I distilled over the water-bath, till no more oily liquid passed over. • Schweigijer— Seider8 Jour. Btl. ix., and Annalen der Pharmacic, x. 298. '} ii 366 MBSITE. 81 i {i J li ►» It appeared now bright yellow, clear, ^ad a spirituous smell, left, when rubbed on the hands, a peculiar smell, and was not acid. To separate the watery liquid, and to free it from creasote, pica- mar, and the yellow colouring matter, it was mixed with an excess of slacked lime, and distilled again over the water-bath. The oil was now colourless, and had a purer spirituous smell. When exposed to the air for some days, it assumed a yellow colour. To deprive it of this colour, it was once more distilled off lime. To separate it from eupion, it was well agitated with 15 times its bulk of water. The greater part dissolved in that liquid, but a small portion sepa- rated and swam on the surface. It consisted of eupion, and an- other substance hitherto unknown. The aqueous solution was distilled on the water-bath, and what passed over was treated with chloride of calcium, to free it from pyroxylic spirit, and water till it ceased to communicate moisture. It was then distilled over chloride of calcium by the water-bath. The liquid thus obtained had considerable resemblance to eupion, but its chemical properties were quite different. M. Reichenbach gave it the name of mesite* It is colourless, has a very aromatic and spirituous smell, when the vapour is drawn into the lungs it has a stifling effect. The taste is burning, followed by a cooling impression. It is as liquid as ether, and as volatile as alcohol. It boils at 143°*5, and has a specific gravity of 0*805. When brought near a candle, it burns with a light yellowish flame, with a shade of blue, without smoke, and without leaving any residue. It dissolves in all proportions in alcohol and ether. Two parts of water dissolve 1 part of mesite, and 2 parts mesite dissolve I part of water. Alkalies do not combine with it, nor do they occa- sion any alteration in its properties. Sulphuric acid mixes with it, and occasions the evolution of so much heat that the liquor boils. It becomes brown, and is decomposed without the formation of any ether. Chlorine gas is absorbed by it rapidly, and in great quan- tity. The liquid neither loses its fluidity, nor acquires colour, yet its appearance is altered. This chloride does not dissolve in water. Reichenbach considers mesite as identical with acetone ; but the properties, which he has ascertained, are too different from those of that body, to permit their being confounded. Mesite, however, is a substance well entitled to a further examination. It has a certain analogy to pyroxylic spirit ; but is obviously different from that substance. * From /itfirns, a mediator. He considered it as acetone. It is not easy to see the meaning of the term mesite, as applied to tliis substance. #■ * Lib. iv tnell, left, acid. ote, pica- an excess lie oil was xposed to )rive it of tparate it of water, ion sepa- , and an- and what 3 it from moisture, •-bath, to eupion, chenbach lell, when ct. The as liquid nd has a it burns it smoke, 'NDIGO. 367 CHAPTER Vr ^SS^ ^^-* sub. processes of dveb^ ° T "fP"'"!^ to superinleml °" j^^ont'ient, ■natters fromX S,? '' ^'"'"-P'-intins-. tK ""'' ""P™'ethe . Jeve™, onpZ4-S„t bod!'e^''o3 . "^^ """««'' "-f ^-deharacfert '' '"^^"^^ "o do not wlLr,£!?"°^™°«e DIVISION I _op nr rrr, dTe""4?hy r^ °*e~t™£"^ ^-=*™. are no. „„ flowers. -ark or two „„ ,,, eoIourL'ta^^'oSe ^^J:l&'^fr^^g^s%^' i^ '•^«„ed fro™ ■>d,>fer;,Ta l"!^™*'"^- There are" ab'r- ?'""" ''<"'"'' yield »%„, b„t r ''•° ''^^""'"'d 4botankf""rP'"'''''°f are the «7 ,|1 ""' 'Pecies from ,,,,3. ""tamsts, all „f which f-out ten ;e'a *f t«J,f «; and the Sft,"^'» "-a'ly extracted '"■o years' old, have ^. f '"'"'•'*' "'"''n the ,1„, • " P ""' «''es of older Teo-rt,u """' *<»'"d to yield m„l •'^j^"' " ""'y one or eonflned Io=t?e' ^JiAta"'"?^"^^- "^ P e^f^ fe""^ •'^'''»' manufacturers t« Ti^' '^''- ^r Roxburo-h If o "*=" " "ot Hindostan, from ti,*", "'"'«"' *cto„w a frf *'""'«ention of ^ Ind,g„ was probaWy k '"wr^u'!' " dye-stuff. ^ """ ''''"'^ ">« '^&t\uT'^rprd.^t^^^^^^^^ -- '^^ - V'ilS- an^rStB^^ -St * ^^- iv. c. 57 or m. ^^ '* ""^^ brought 368 COLOURING MATTERS. from India. The descriptions of both so nearly ai^ree, that it is probable Pliny, who dedicates his book to Titus Vespasian, bor- rowed his account from Dioscorides, who is supposed to have writ- ten in the time of Nero ; though he does not give the name of Dioscorides in the list of authors whom he consulted. They inform us that then are two kinds of indigo, one which is formed spon- taneously, lil- - a froth upon Indian reeds. The other kind, says Dioscorides, comes from the workshops of dyers attaching itself to the vessels, from which it is removed and dried.* This, I think, shows that indigo was used as a dye-stuff in India, and that Dios- corides was aware of it.f Be that as it may, the value of indigo as a dye was not known in Europe before the middle of the 16th century. It is not even men- tioned in the Plictho, a celebrated work on dyeing^ published in Italy in 1548. The Dutch first imported it from India, and made its valuable qualities known in Europe. Even as late as the middle of the 17th century, its use was restricted in different countries. It was prohibited in England during the reign of Queen Elizabeth, and the prohibition was not taken off till the reign of Charles II. It was prohibited also in Saxony. In the edict it is spoken of as a corrosive substance, and caWedybodJbr the devil. Colbert restricted the French dyers to a certain quantity of it. Soon after its importance as a dye-stuft' began to be generally understood, it was cultivated in Mexico and the West Indies with such success, that the indigo from these countries was preferred to every other. But towards the end of the 18th century it began to be cultivated in British India ; and the culture was carried on so successfully, that East Indian indigo soon recovered its original character, and being furnished to the dyers at a cheaper rate than that from Mexico and the West Indies, it has in a great measure superseded the indigo from these countries, Hindostan at present supplying almost all the indigo employed by the dyers or calico- printers in the various countries of Europe. The dyeing principle of indigo resides in the leaves, and is most abundant when the plant is in blossom. At a later period the indigo extracted is more beautiful, but smaller in quantity. For the first accurate account of the process for extracting indigo from the leaves of the indigofera, we are indebted to Labat.J Since his time some improvements have been introduced into the manufacture ; but the mode of rearing the plants still continues the same. In the West Indies the seeds are sown in March, in * Alterum infcctoriic dant officinae et est spuma purpurea innataiis cortinis, quam detractani artifices siccant. f Dr Bancroft (on Permanent Colours, i. 97) informs us that Dioscorides con- sidered indigo as a stone ; but the passage just quoteri shows that this is a niistako. % Jean Baptist Labat was a monic of the order of St Dominic, wlio, in 169:J, went to America as a missionary. On his return to France, he published " A New Voyage to the American Islands," in 6 vols, duodecimo. It is in this book that ills ac^'ount of the mannfacti;rc of indigo is to be found. See also Lewis' edition of i>ewraan's Chemistry, p. 435, where Labat's account is transcribed. e, that it is ipasian, bor- have writ- ;he name of rhey inform irraed spon- r kind, says ling itself to his, I think, i that Dios- ot known in t even men- lublished in I, and made 5 the middle ountries. It 1 Elizabeth, Cliarles II. )ken of as a rt restricted e generally Indies with )referred to •y it bearan irried on so its original sr rate than (at measure at present i or calico- find is most period tlie ting indigo to Labat.J sd into the ntinues the March, in iortinis, quam scorides con- I is a mistaku. ho. in 1 693, iil)lished " A in this book '. also Lewis' inscribed. 'S t«-enches about a foot a.nn^ 369 perience. Th,, ;„ i e ? ^^°"' ""tensive cmfit.?! ', '" "'<= heiffht •jWed them, i„' ™tt"^* <'«rt;„„rofXe^n,?"'' "'?"■'•«'' '"^- 't deseru. ii" TlX^''^"- to overcome the ^f« ^^^^ o- Kevol„ti„„, ™if' °Ti°S°.»t the £/„„?„';'''? "f'o'; and d.fc:riro^5.r V'"-'- xr '° '-^ *'-p^ '-t ■"illions of Znrf! ' P™''"'^". as much .-.T •T'"'^" "«« a Pro! "f "■eprice.'Td" h?r"„ro'/- '^''^ ^"4""^;^" "T-"''""- Sr' ""!"'°'' »4ted "n'rnS •'""' "anufecCrs tII'"'""" wliat quantity of tlieV.1, »^, ™'a « affreeino- u,;.r.l '"o "ost at a fixed price a7 ' "i"^ "an produce 1! ^'''^ """"os for ■"othert „tS/:-'''-fVh«C£beT;i^^ -"-^'rifT'^'-^^^^^^^^^ «-it is specially if ,-^•^"■'''0 kept for „ very sto,!"'?"^ "^ Possible, destroying the i„dZ^' " '»" °f fermentaliS tak s„ 'T' """ •"»'■« W.th those bundle; a I, "^ ' '»"?'»«)' of from at "S ?* "'?'"'•' a"d alloVertoT'^'r"'- '"'"'o »tate of the woa.aZ%f-"'"'"'S '° the skiU „f tt!'? '^»'- " PO"od j-'a-ts be stcepe too , P'T "'' "«> Process reJ^-P'"""-'''' ""J the '«™a as it ;. ,„V , , """'- the indi™ „rrr ! '^'"l""'os care. If the "'e 'luant ;; 7";^ V."'o plantc,:' '"jf" ' ''« """^h dan,a.ed, „ . The yelL eZ'r^d",;:,'"'''^'' 'hmi„i,|„'J^^ ''« ^"-'oped too short, -t^^£:^.dlF^^ '^Ihf fc-7 " -dish) "°" '» -p ''.e w4in::;tt;: . .t ~ -J ™rat,r "■»„»,■, ,„,„„„ „ ^ °'.'""' have become con,- ,, "^cr(Mtions, n. | jg. 370 COLOUniN*} MATTKRS. i ill I *>4 pletely formed, and separated from the mother liquor. If the beating be continued for too short a time, a part of the contents will be lost ; if it be continued too long the grains will be again broken down, and it will be with the greatest difficulty, if at all, that they can be separated from the liquid. When the workman considers that the grains are properly formed, a few pailfuls of cold water, or sometimes of lime water, are added, the whole is then gently stirred with a circular motion, and the fecula allowed to subside. The supernatant liquid is drawn off, and the blue precipitate at the bottom (being previously washed with clean water, if lime water had been mixed with it) is removed into a copper boiler till it assumes the appearance of effervescing, or till it ferments, as the planters term it. Some planters do not boil, but only keep it milk-warm, till the same appearance takes place. When boiling is used the indigo is much lighter, or more bulky, than when the liquid is merely kept warm. It is then placed upon a bamboo frame, covered with cloth, in the form of a filter, and all the liquor that will is allowed to drain from it. It is then placed in proper frames, and strongly pressed by means of screws, then taken out and cut into cakes of the proper size, and placed in the drying-house. In some districts it is now ready for the market. But farther up the country it is in this state loosely packed in boxes, with a layer of coarse hemp, or some similar material, placed between each layer of cakes. Being allowed to stand for some time it becomes hot, and a quantity of moisture is exuded, or in the language of the planters, the crude and bad humours are sweated out. It is now again placed in the drying- house, and when thoroughly dry, packed up and sent to market. One becgah (the third of an acre) of land, in an average season, yields 20 bundles, each 5^ feet in girth. The usual price paid in Jessore to the ryots is one shilling and ten pence halfpenny, for eight bundles. The leaves of the indigofera vicld a green infusion to hot water, and a green powder may be precipitated from it ; but unless a fer- mentation has taken place, neither the colour nor the properties have any resemblance to those of indigo. There is little doubt that in the leaves it exists in the state of white, or deoxygenized indigo, and that during the fermentation it combines with the re- quisite quantity of oxygen to convert it into blue indigo. The evolution of carbonic acid renders it not unlikely that the white in- digo was in combination with some princi])le (probably of an alkaline nature), which was decomposed during the fermentation. Dr Roxburgh's process for extracting indigo from the leaves of the ncrium tinctorum is shorter. The leaves are kept in a copper j'ull of water, supported at the temperature of 1G0°, till they as- sume a yellow hue, and the liquid acquires a deep-green colour. The liquid is then drawn off, agitated in the usual manner, and the indigo thrown down by lime water.* * Bancroft on I'criiianont Colours, i. 423, [uor. If the tlie contents will be again ilty, if at all, perly formed, r, are added, tion, and the rawn off, and washed with removed into iscing, or till not boil, but )lace. When y, than when cloth, in the drain from ' pressed by f the proper !ts it is now in this state ip, or some 3ing allowed of moisture >ide and bad the drying- • market, 'age season, ice paid in Ifpenny, for 3 hot water, mless a fer- 1 properties little doubt eoxygenized vith the re- iigo. The e white in- an alkaline e leaves of in a copper ill they as- ;en colour, er, and the In this state the? h ""^ ''^^«'' and exnot^ .'"^?^ "P into ball" the balls with water Wk V'^^oted, if neceJ.. 1 ^n^moniacal thet^o«rfisa,]^^;^^^- When 't has contin^d f '^' '^^ «P»nkling !oW as d dye-stuff n''" *° ^ coarse nowl ^"^ ^ sufficient timf ^n Germany since the c™^*' '" *^« ^^n^e subject h?" t '^^"^^ ^^ *"*« of^a blue CO o„^^n^•' ''' -4^ ZSr^'^^ '^ ^^'' fro'n fic'-g-man showed Inn "^ '"capable of beinri ^, ^^ "^^tter desti- "^eree contained ontf-'^^' *''^^ ^^0 parts o^f?.'^.^^ ^ dye-stuff "'-tter, or oxide ofi'^^r^' «^ P^^e So tho ' '""^ ^^ ^om- "Y^ dissolved by vS.p'^"'"' '^^re«in.**"Part of!f' ^^^"^ ^^^-thy f "d by alkaline leyl r"'' P?^^ by alcohol and n . u"'" impurities cahco-printer's va Tn ii.'"? ^"^^ ^'"^iffo, is to h Wue colour by sulnh . i'""^ ^^^ indigo L u^^^ '"^^^urse to thp -e water. Vhtt^r^^^.' ^^ ^^n \Z'''T'' ^^ ^ ot It be j,ut into an onpn *''\' '°^"tion is vpH. "r^>^ "^^ans of it has been Jono- l„^ , "* ^ned, it is „„ "P"scuJa, V, 36. . , „, ^^'' ^"'' vi. j, anj M 372 COLOUIIING MATTEHS. ) ; I". ' i >( ! drawer, in London, who gives a method for collecting the snb- limate.* • Mr Cruni, after in vain endeavouring to sublime indigo by the process of Chevreul,t found the following method to answer : — He employed the covers of two platinum crucibles, nearly 3 inches in diameter, and of such a form, that when placed with their concave sides inwards, they were about three-eighths of an inch distant in the middle. About the centre of the lower lid were placed thinly about 10 grains of indigo, precipitated from the dyer's vat, not in powder, but in small lumps of about a grain each ; then having put on the cover, the flame of a spirit-lamp was applied beneath the indigo. In a short time the indigo began to melt, and the vapour to be disengaged, which was known by the hissing noise that accom- panied it. 'rhe heat was continued till the noise nearly ceased, when the lamp was withdrawn, and the apparatus allowed to cool. The sublimed indigo, upon removing the cover, was found planted on its inner surface, with sometimes a few long needles upon the bottom of the apparatus, which were easily removed from the button of charry matter that remained. In this way he obtained from 18 to 20 per cent, of the indigo employed.^ When 10 grains of precipitated indigo were sublimed in this way, Mr Crum obtained 1'88 grain sublimed indigo, 6*44 grains of cinder remained, and consequently 1*68 grain of volatile matter escaped. 10-00 Thirteen grains of the same indigo, kept a quarter of an hour at a strong red heat in a small platinum crucible, firmly, though not exactly closed, left 7*9 grains of cinder, which is equal to Gl per cent. Indigo sublimes in long flat needles, which readily split when bruised into four-sided prisms. Viewed at a particular angle they have the most brilliant and intense copper colour ; but when lying in heaps they have a rich chestnut-brown colour. Besides these needles, indigo is formed in plates, much broader than the needles, and extremely thin, twisted sometimes almost into tubes. When viewed obliquely through a microscope they appear opaque, and copper-coloured like the needles ; but when held perpendicular to the rays of light, they are seen to be transparent, and of a beauti- ful blue colour. Tlie vapour of indigo is transparent, and of a most beautiful reddish-violet colour, resembling the vapour of iodine, but dis- tinguished from it by the shade of red. The sublimation takes place at the temperature of about 550°. The melting point of indigo, its point of volatilization, and that at which it is decomposed, are remarkably near each other. * Aiiiials of Philos()|)hy (New Series), v. 81. f Ann. do Chini. Ixvi. '24. J Annals of Philoso|)hy (Second Series), v. 82. at with C haus but \ the id the Ni yellov names Til aftori the an 71ie INDIGO. 373 sub- V tbc LHe cs in ncave in the thinly lot in ig put ;h the mpour iccom- ;eased, o cool, planted )on the om the ibtained ) grains )btained lour at a lusjh not Gl per [lit when igle they jien lying [ea these needles, When Ique, and liculav to la beauti- l beautiful but dis- lon takes point of loraposed, The specific gravity of sublimed indigo is 1"35. The crystals of indigo sublime when lieated in open vessels, leav- ing no residue. In close vessels the vapour is at first reddish-violet, as in the open air ; but as the heat advances it aipiires a tinge of scarlet, and before it is entirely decomposed, becomes deep-scarlet, and then orange-coloured : a quantity of charcoal is at the same time deposited.* Indigo is d(!stitute both of taste and smell, and has neither the characters of an acid nor a base. When heated on platinum foil it ^ives a beautiful purple smoke ; and if the heat be rapidly aug- mented it fuses, boils, catches fire, and burns with a lively flame, giving out much smoke, and leaving a quantity of charcoal, difficult to burn, but which may be entirely consumed without leaving any residue of ashes. It is insoluble in water. When alcohol is boiled over it the liquid assumes a blue colour, but gradually lets fall a very minute quantity of indigo, and becomes colourless. Olive oil, and oil of turpentine, as was ascertained by Mr Crum, act precisely in the same way. Indigo is insoluble in ether. Neither dilute acids nor alkaline levs ay d;,,olv,;,| " a":'.!™» »"'P1"*C of a,n,„„„i, ,,,. , powder is „„i,,. ,,..' ''1? .''y'lrosi--.i cts i, m' „ . "•"■'°' "!™"Sl' powder i8 „ui.,.'i,. "i? "yilroso.i ,>as i. m, u . ■* ' ""'""S-''' exclude a.I» ,t • .'^"!"i'l-5.ndi^/„,Hr'^l'"...!""»> '".' 'W powder ia ;„.„:,,.'" V ''J''™Si-.„ gar is Z 7. ^'^°' ""•""?-''' exclude almo™l,'^'' ■'^"'"•"I'Standin" aiw,™"^" '" P"'*' «" the . This whUesub to rtS ?f "","'" ™"«»'« S e '''^'"'• tint wh7„ dried rr ''""P-""" «»'»"' anTicl", "''™ P'""""" contact with "i;"„e^'"„'. °°,?f f "'kali or li,„e water be hr . • Senerated, and mZ^t'. "' ^''* '» al-sorbed wbil'„ ■ r "?"" " Liebigdis'solvedTwtrt'or ?" """" »""- oftb"ue"° " /••- over a mercurial troK ;° "''.'-°=™ '" ammonia and J l^"'' generated indin-„i,„T° ",".'" """'act with ovvwr, „ fred it ^:— -»a-S.--.«£d^ ■■' oonlinr.l-tr :?'-"= «'=">« «f i»*«o .«-,75 L '^^ lute of oxygen ?, ,/ '!^'"'"' "'"' «•■»( ind°4^e„ ?.' ? "1""' """ (theinereaSUtbtnfT """'" ""' be ills '^"'"•''^/le.ti- ;nd,g„„e„ i, onlypjn'"^ °' °''->'-™ "l-wrbed by ih„ ?'"""'; >t probable that li df^!""' <>■•. »•«. les, than 1 atom, \°Z f Now 4-6' is very n'f '"!'"'. ^'^^ i^n^bed 4'6-''"ar?"'/"« P^^ts parts of indi'o^ &wtf^ "* ^''« -hole oxytenCnLn f^^^"'^ confidence TK^'^f." ^Wment seems tol k ! "^ ^" ^^^"^ «f -• The .b,ect has been lat^f; ZZ^'^'^i^ ' Ann. <)i. /'!.:._ . . _. * Ann. do Cliim. el do Ph.c *-' "^ ' nys. XXXV. 2Cf). Ml I'j t 'Iniite dc (.■Iii„,i,., ,i ^^^^ 37G r 5: ''fi ' COLOl'KINd MATTKItS. huH subjected indigogcn to a new niuilysis, from which he hu» deduced its composition to be 16 atoms carbon = 12 or per cent. 72'73 6 atoms hydrogen = 0*75 — — 4*54 1 atom azote = 1*75 — — lO'Ol 2 atoms oxygen = 2*00 _ — 12' 12 16-50 100 According to this analysis, it is a hydrate of irnUgo, or indigo united to an atom of hydrogen. Dumas has entered into no details, so that we have no means of judging of tlie accuracy of his analysis, which must be ditficidt. lint he himself places full confidence in his result.* Chemists, however, cannot adopt his conclusions till he furnishes the details, to enable them to judge of the accuracy of the analysis. It has been already mentioned that indigo dissolves in concen- trated sulphuric acid. By this treatment it sutt'ers a remarkable change, being converted into a blue pigment ditfercnt in its nualities from indigo, with which Saxon blue is dyed. This blue substance was first accurately examined by Mr Crum, who has distinguished it by the name of ccrtiUn.] The mixture of the blue substance with sulphuric acid is a semi- fluid, which requires a considerable quantity of water to dissolve it. The cerulin is precipitated from this solution by any salt of potash, and the precipitate is a combination of cerulin and sulphate of potash. Mr Crum distinguishes it by the name of cerufeu-sulphate of' potash. This salt is soluble in pure water ; but not in solutions of potash salts. The salts of soda form also precipitates in the solution of cerulin with sulphuric acid, and these are likewise insoluble in solutions of potash or soda, though soluble to a certain extent in pure water. When heated, these ceruleo-sulpbates dissolve even in solutions of their salts. On cooling, the greater part falls down in blackish grains ; a portion, however, remaining in solution. The soda com- pound is more soluble than that of potash. The salts of ammonia likewise form precipitates in the sulphuric solution of cerulin, when not much diluted. The precipitate dis- solves readily in hot solutions of ammoniacal salts, and again separates when cold, the whole mass becoming curdy. The preci- pitate seems to be a combination of cerulin with sulphate of am- monia. It is much more soluble than the ceruleo-sulphate of potash or soda. Potash and soda and their salts decompose it. Hot water dissolves it abundantly. It is soluble also in between 40 and 50 times its weight of cold water. Similar compounds may be formed with barytes, strontian, and lime, and probably with most of the bases. But the salts of magnesia have not the property of preci- pitating cerulin from its solution in sulphuric acid. * Aim. (Ic Chilli, ol do VUys. Ixiii. 2C9. i Annuls nl riiilosophy (Second Scries), v. 88, INDIUO. 37; lie llUft ;o unvto«l litails, so analysis* idcnce iu furnishes ! analysis. 1 concen- jmarkablc s qualities substance tinguished . is a semi- dissolve it. ; of potasb, e of potash. of potash. of potash of ccrulin solutions of Lure water, [solutions of In blackish soda coni- ('orulco-sulpliatc of potash has so deep a hliie cnh)ur, that whtMi wetted with water it appears b/ncft. When (h'v it lias a shininj; stronjT cojjpor-red colour. \iy transmitted light it is blue. It attracts water from the air with great rapidity. Cold water dis- solves TTjTjt'' of its weight of this substance, and forms a solution so deejdy coloured, that when diluted with 20 times its weight of water in a phial, an in(;h in diameter, it may be just seen to be trans- lucent. Water in a wine glass containing 6,xi!ou..th of its weight of it is distinctly blue coloured. Mr Crum found that the saturated solution was precipitated by spring water, and by every licpiid tried except distilled water. Hence the presence of any foreign substance in i)ure water greatly diminishes its solubility. If the solution be diluted with 20 times its weight of pure water, it is still precipitated h^, solutions of the salts of potash, soda, lime, barytes, strontian, lead, and mercury. The addition of sulphuric or nmriatic acid does not dissolve the precipitate. But neither annnonia nor any of its salts precipitate this weak solution. None of the salts of magnesia, zinc, or copper, nor the solution of alum, sulj)hate of manganese, perchloride of tin, sulphated protoxide or jjcroxide of iron, nor nitrate of silver, decom- pose it. It is not precipitated by any of the acids, by infusion of nutgalls, nor by gelatin. Alcohol and ether do not precipitate the weak aqueous solution, though they do not dissolve any of the dry substance. Ceruleo-sulphate of potash dissolves readily in con- centrated sulphuric acid, but not in concentrated muriatic acid. Protochloride of tin gives the solution a yellow colour, by de- oxidizing the indigo. It becomes blue again by the addition of any substance, as salt of coi)per, capable of imparting oxygen to it. When heat is applied to the blqe substance it does not melt ; no purple vapour is given off, and in consequence of its being defended by the saline matter, a strong heat long applied is requisite to re- duce it to ashes. When indigo is dissolved in sulphuric acid considerable heat is produced, but there is no evolution of sulphurous acid. The solu- tion is at first yellow ; if it be dropt into water it instantly becomes blue, and the indigo prcci})itate3 unaltered, leaving the liquid colourless. If the solution be kept undiluted for 24 hours the indigo is converted into cerulin. Mr Crum analyzed cerulin by mixing ceruleo-sulphate of potash with oxide of copper, heating the mixture to redness, and collecting the products. He has drawn, as a conclusion, that cerulin is a compound of 1 atom indigo . . . 15'G25 4 atoms water . . . 4*5 1 *! m V]' 20-125* Such is the result of Mr Crum's experiments on the action of ♦ AnnaU of I'hilosopliy (.Second Scries), v. 94. n ' ' I. ^i; b' ■ ♦! 378 COl.OintlNO MATTKnS. sulpliiiric acid uii itidi^o. Hor/i>liii.s Iiih tukeii a diti'crciit vluw uf tlio Buhjcct.* Aci'unliii^ tu liiiii, wIkmi imli^ro i.s d'hsi^olvi'd in Hidpliiiru* arid u coinbiiiution takes placo hctwoen tlieni, and two now acida are rorined, Ui which lie haa j^ivon the names of hi/posu/pho-im/if/vtic acid, and snlpUu-indiyotic acid. 'I'lie «tronj^er the sulphuric, acid eniph)ycd, tlio f,'reuter is the (piantity ot* tlie lirst of these aclda furnied, and the smaller of the second. English sulphuric acid gives more sulpho-indigotic acid than acid of Nordhausen does. An account of these two acids has heen given in a previous Section ot this work, when treating of the vegetahle acids. See page 11)7. M. Duniasf has lately examined this solution of indigo in sulphuric acid, lie finds it to possess the characters of an acid., and has given it the name of sulphindilic acid, and assures us that it is a compound of 1 atom indigo 1(]'375 2 atoms sulphuric acid . . . 10 26-375 It has the property of combining with the bases and forming salts, some of which are capable of crystallizing. The sulphindilate of potash crystallizes in fine silky plates, and has a deep-blue colour. It is composed of 2 atoms sulphuric acid . . lU 1 atom indigo .... 1 ()'375 1 atom potash (] 32-375 The sulphindilate of barytes separates in flocks from the hot solu- tion while it is cooling. Its composition is precisely sinular to that of sulphindilate of potash. The purple matter which precipitates when indigo is dissolved in sulphuric acid is, according to Dumas, a comi)ound of 2 atoms indigo .... 32-75 2 atoms sulphuric acid . . . 10 42-75 It possesses acid properties and has been called by Dumas sidpho- pur mric acid.X With potash it forms a purple salt composed of 1 atom sulphopurpuric acid 1 atom potash. It is clear that these two acids o. Dumas are identical vnli the sulpho-indigotic acid and hyposulpho-indigotic acid ct \Wi r-Jii'v^-. Sulphuretted hydrogen gas possesses also the property of re- ducing the indigo in these acids. Hence the reason why the liquid iio.s a yellow colour when the sulpho-indigotate or hyposul- * Traiu' Uj < ;r.'nie. i. SI. f Ann. (Ic C'him. et de Pliys. Ixiii. 265. I Ibid. p. -IW). of tlio pUuric iiciila tlii/utic V. aciil il gives (. An jtion of 11)7. li^o in :>,iil5 and at it ii ng salts, itca, and lot aolu- ir to tluit iolved in siilpho' *he -i-i fty of re- wliy the hyposul- xiii. 265. INUKiO. :i7U plio-indigotato of lead is dccoinposiMl by tlint jjns. It even reduces tliea(|U(M)us rtdliilionof tlu'se iw.'nU, provided it be assisted by raisinjf the tein|)eratiire of tbi! li(|uid to l'j.'i''. This deoxidi/inff process is considerably opposed by the prcsotti i; of an excess of acid in the liciuid. The protochlorido of tin prod cflect when assisted by heat. produced tb<; same deuxidizinjf Aecordini^ to Mitscherlich, when these aeld« are saturated with a base, the sulphuric acid only eontl)ii •" with ii, .tinl the indi^ftt (tho cerulin of Cruni) acts in a way similar to the wiitor of ci vMtiilliaa- tion in simple salts. Mr Crum, in his researches on indij^o, discovered, that if tlio ac- tion of sulphuric acid on indigo be stopped at a certain point, a new substance is formed, posscssinff rather singuhir properties. It is formed .it the instant that indiffo changes from yellow to blue, by the 'trti.)), ot sulphuric acid. Mr Crum has distinguished this sub- 8t!inc ' ) : ' iime o( phenicin;* while Herzelius, who has also oxa- niiuod it, givc^ it the name o( purple nfinditfo.'\ Ml' ^ ' "um obtained phenicin in the following manner : — He mixed 1 port o^ purified indigo with 7 or 8 parts of concentrated sul- phuric acid in a stoppered phial, and agitated the mixture o(;ca- siondJ", till it became of a bottle-green colour. It was then mixed with a large quantity of distilled water, and thrown upon the filter. By continuing to wash the filter with distilled water, the liquid, which was at first colourless, became more and more blue, and after some time all the indigo which had been changed passe a chemical analysis, and con- cluded from liis experiments that it is a compound of 1 atom indigo .... 15'()25 2 atoms water . . . . 2 25 17-875 He has given us the following method of preparing plienicin in greater quantity, though not so pure: — Mix together 1 part of in- digo in powder and 10 parts of concentrated sulphuric acid in a ])hial, and agitate for some time, till the blue colour which the in- digo loses at first is completely restored. This, at the ordinary heat of summer, requires about 3 hours. At the temperature of 100°, it is effected in about 20 minutes; and indigo, mixed with sulphuric acid, at the heat of boiling water, becomes blue the in- stant the mixture is made. At 45°, 10 or 12 hours are necessary, and the time increases as the temperature diminishes. Pour this mixture into a large quantity of distilled water, and filter. Take the precipitate off the filter, and wash it well with distilled water, containing as much sal ammoniac as will prevent the substance from dissolving in it. Then collect it on a filter again. Dissolve the precipitate anew, in a large quantity of distilled water; heat the solution, to drive off any particles of air which might prevent the impurities from subsiding, and let it stand two or three days in a tall vessel. Then draw off with a syphon as much as may bo thought perfectly clear, leaving the remainder to be washed with more distilled water. Add to the solution any alkaline salt, till the phenicin precipitate, then throw it on a filter, and wash it with dis- tilled water till the liquid refuses to pass through. Phenicin dissolves in the water of liquid ammonia without injury ; but the fixed alkalies dest' oy it, though not very readily. Chloride of tin precipitates the solution, but gradually redissolves the pre- cipitate, forming a yellow solution ; and the phenicin is thrown down again of its own colour by the salts of copi)er. Phenicin dissolves readily in concentrated sulphuric acid, forming a blue solution; and if this be poured immediately into water, the greater part of it is j)recipitated again, the impurities of the acid being sufficient to pre- vent its solution in water. A portion is converted into cerulin, which remains in solution. When allowed to remain dissolved in sulphuric acid, it is soon entirely converted into cerulin. Conse- quently, in preparing phenicin by the last described process, it is impossible to prevent the formation of a certain quantity of cerulin. Such are the properties of phenicin, as described by Mr Crum, to whom we are indebted for our first knowledge of it. The great ])urpose to which indigo is applied, is to dye woollen cloth, silk, linen, and cotton, blue. It constitutes a most beautiful and very fixed colour, and combines with the fibres of the cloth, without the necessity of a mordant, its affinity, es))ecially for woollen and silk, being verv considerable. But to enable it to combine with the cloth, it nmst be in a state of solution. Now, there are two d con- INDIGO. 381 licln in ■t of in- ;id in IV tVie iu- jrdinary rature of ted with J tlie in- Qcessavy, t>our tliis .. Take ed water, ince from ssolvc the heat tlie ■event the days in a s may he ashed with dt, till the t with dis- )ut injury ; Chloride the pre- own down n dissolves utiovi; and irt of it is ent to pre- cerulin, issolved in Conse- ocess, it is of cerulin. r Crum, to [ye woollen st beautiful the cloth, for woollen lubine with ere are two ways in which this state is induced. 1 . The indigo is deprived of its oxygen, and reduced to the state of indigogen. Now, hidigogen has the property of combining with alkaline bases, and of forming with them a compound which is soluble in water. 2. The indigo is dissolved in sulphuric acid. This is the method employed for dyeing what is called Saxon blue. I. Indigo is converted into indigogen, and dissolved in various ways. It will be sufficient here to describe the methods most com- monly employed. 1 . The calico-pr (titer's indigo-vat is made by mixing 1 part of in- digo in powder with 3 parts of slacked lime, and 150 parts of water. After this mixture has been well agitated for some hours, 2 parts of pure and recently crystallized sulphate of iron are to be added. The liquor is well stirred, till the reduction of the indigo has taken place. This is known by the liquid assuming a yellow colour. The lime decomposes the sulphate of iron, setting the protoxide of iron at liberty. This protoxide being every where in contact with the indigo, abstracts its oxygen, being converted into |>eroxide of iron ; and the indigogen, in proportion as it is formed, combines with the excess of lime present, and dissolves in the water of the vat, forming the yellow-coloured liquid. If the indigo employed were perfect.y pure, the proportions indicated by the atomic weights of these different substances would be 1 part of indigo \h part of lime 4i parts of sulj)hate of iron. But as the indigo contains usually more than half its weight of im- purity, it is obvious that half these quantities, or 0*75 lime 2'25 sulphate of iron, will be sufficient. It is obvious from this, that the quantity of sul- phate of iron used by the calico-printers for making their indigo- vat is rather too small. The slacked lime used is about twice as much as is necessary. But as it is the cheapest constituent, and as the excess does not dissolve in the water, it does little or no injury. And perhaps an excess of lime may be proper to supply the place of that which is continually converted into carbonate at the surface of the vat, and which, of course, falls to the bottom of the vat in the state of an insoluble powder. The ingredients of the indigo-vat being thus mixed, and the in- digo reduced, the vat is covered to preserve it as much as possible from the action of the air, which would revive the indigo, and precipitate it from its solution. It ought to be recollected by the calico-printer that lime has the property of forming an insoluble compound with indigogen, as well as a soluble ; and that, therefore, too much lime may be injurious. The cloth to be dyed is dipt into the vat, and being drawn out is left exposed to the air. The indi- gogen immediately begins to absorb oxygen from the atmosphere, ir' ; 1 t '^^ 382 COLOUIiING MATTEIKS. ii I ! ' i ' » and becomes blue. The mixture of the yellow and blue causes the cloth at first to a])pear green ; and it only assumes the blue colour when the whole of the indigog-en is converted into indigo. The depth of the shade of blue depends upon the number of dips to which the cloth is subjected. 2. The orpiment vat. This vat is made by mixing together, and raising to a boiling heat, 1 part of indigo in powder, 2 parts of potash, and 20 parts of water, adding 1 part of recently slacked lime, and lastly, 1 part of orpiment in powder. The whole is boiled for a fe..' minutes, and then the clear liquid containing the indi- gogen united to the potash is drawn off. The sulphur and arsenic of the orpiment unite with the oxygen of the indigo, and convert it into indigogen. This solution, thickened with gum or roasted starch, is employed by the calico-printers when they wish to apply the blue colour to certain portions only of the cloth by moans of the block. 3. Woad or pastel vat. What is called pastel, and sometimes iroad,* is a preparation of the isatis tinctoria. The leaves of this plant are cut, dried as rapidly as possible, reduced to powder, or rather into a paste, which is placed upon an inclined plane, furnished with conduits to carry the juice that runs out into a reservoir. Here it ferments, and swells, and cracks. These cracks are filled up by pressure, and the mass is moistened, from time to time, and every two or three days it is well kneaded by the feet. The fer- mentation is continued for twenty or thirty days, and then the whole is made up into cakes of from 1 to 3 lb. each, which are dried. By a second fermentation, to which it is often subjected, the quality of the pastel is improved. Thus prepared, pastel has a yellow or greenish-yellow colour, and gives a green stain to paper. Old pastel answers better as a dye- stuft' than that which is new made. To prepare the pastel vat, 4 parts of indigo, .50 parts of pastel, 2 parts of madder, and 2 parts of potash are employed. The indigo is reduced to powder and boiled with the potash. The pastel is mixed with 2000 times its weight of water, and being heated to 194°, and kept for some time at that temperature, the indigo and the other ingredients are added, taking care to stir the whole well. Small portions of lime are added at long intervals, till 1^ parts altogether have been added. In many dye-works, besides the madder, about half a part of bran is added. The mixture is al- lowed to cool slowly, while the lime in small quantities is added at in- tervals. By degrees the pastel and madder ferment, probably giving out gas, by means of which the indigo is deoxidized, and converted into indigogen. This fermentation continues for a very long time, and it is sufficient to add to the vat, from time to time, new matter in proportion as it becomes exhausted, to be able to continue the • Woad is more commonly applied to tho reseda luteola, a plant which yelds a j'cUow-dye stuff, to be mentioned afterwanis. INDIGO. 383 368 the colour The :) whicli ler, and parts of slacked is boiled the indi- L arsenic onvert it employed colour to lometimes cs of this lowdcr, ov furnished reservoir, i are filled , time, and The fer- n the whole dried. By quality of ;olour, and ir as a dye- Ivbich yelds a dyeing processes with it for a great length of time. The use of the lime is to retain the brown matter of indigo, which dissolves in the potash in proportion as the lime falls down in the state of car- bonate. II. The solution of indigo in sulphuric acid has received the name of Saxon blue, because the process was discovered by Barth, at Grossenhain, in Saxony, in the year 1810. The indigo is re- duced to a fine powder, and dried in a temperature of between 1 20° and 140°, to free it as much as possible from water. It is then added by small quantities at a time to concentrated sulphuric acid. From 4 to G parts of Nordhausen acid and from 8 to 1 2 parts of Eng- lish sulphuric acid are employed to dissolve 1 part of indigo. The solution may be heated to 212° without undergoing any decomposi- tion. But the foreign substances, with which the indigo is always contaminated, are much more easily decomposed. Hence the reason why the indigo should be added in small quantities at a time, in order to prevent the evolution of heat, which would occasion the disengagement of sulphurous acid. And this disengagement would be attended with injury to the indigo itself. When the solution is completed, the vessel containing it must be shut close, to prevent the absorption of water from the atmosphere, and left at rest for 24 or 48 hours, according to the temperature of the air. The sul- phuric acid dissolves, i.i the first place, the foreign bodies mixed with the indigo, and acquires a yellowish-brown colour. The indigo is afterwards dissolved, and the acid assumes a deep-blue colour. When the solution is complete the acid is poured into 20 times its bulk of water, and the whole is passed thrt)ugh a filter. There remains on the filter a substance which gives a green colour to water after the solution has passed through. It must not be washed, because it consists of impurities, which would injure the liquid as a dye. When wool or cloth is digested in the blue liquid, the cerulin be- comes fixed upon them, and gives them a blue colour. What re- mains is a yellow-coloured acid liquid, containing free sulphuric acid. If we wash the dyed cloth with a little water, and set the liquid to digest in a temperature of 104°, it becomes yellow. It contains, in solution, the gluten of indigo combined with sulphuric acid. It requires a great deal of water to wash ofl^ the whole of this matter. We know that it is all dissolved by the liquid beginning to assume a blue colour. If wo now digest the cloth in a solution of carbonate of potash, containing 1 part of carbonate to 200 parts of water, the liquid assumes a blue colour, and the cloth acquires a dirty-red colour. This is owing to the red matter of indigo which the alkali does not dissolve, and which remains fixed upon the cloth. From all this it is evident that the foreign matters in the indigo have a great ettect in deteriorating the colour of Saxon blue. 384 COLOUlllNG MATTERS. i ;.'.- i ,^ I • f The most beautiful Saxon blue is obtained by means of the ceruleo- sulphate of potash of Cruin, or the sulpho-indigotate of potash of Berzelius, wliich precipitates when potash is poured into a solution of indigo in sulphuric acid till } or i of the acid is saturated. The soluble blue which remains in solution is separated by the filter from the precipitate, which is allowed to drain. It is then dissolved in water and mixed with sulphuric acid. This liquor gives a very line blue colour to wool. To dye those tissues blue which do not combine with the blue acids of Berzelius, we may begin by steeping them in a solution of alum, or in a hot solution of chloride of barium and bitartrate of potash mixed together, and afterwards plunare them into the blue liquid. When alum has been employed, a little carbonate of potash is added to the blue acid solution ; because it is necessary that it should contain an excess of alkali. It is the subsuli)ho-ii'..'.!gotate of alumina (according to Berzelius) which in this crise attaches itself to the cloth and dyes it blue. When we employ a mixture of chloride of barium and bitartrate of potash, the acid solution may be used without any addition, and the dye which fixes itself on the cloth is sulpho-indigotate of barytes.* SECTION II. OF LITMUS, OK TURNSOLE. Litmus, called lakmus by the Germans, and turnsole by the French, seems to have been prepared at first in Holland, and the Dutch seem still to be the manufacturers of it. It is sold in small cubical cakes of a dirty-blue colour, which are light and friable. At first it is said to have been ])repared from a lichen from the Canary Islands (doubtless the roccella tinctoria). But at present the leconora larlnrea is used, which is said to be chieHv collected in Norway. Probably other lichens are also employed in the manufacture. The lichens tare cleaned, reduced to powder, and passed through a seirce. This j)owder is mixed with i)utrid urine, and left for some time in vessels. The ammonia from the urine acts on the powder, a kind of fermentation is produced, and the blue colour is develoj)ed. It is probable that the urine is distilled in the first place, and only the ammoniacal solution that comes over employed in this process ; for litmus contains no acid, which cuuld hardly be the case if urine were employed in its j)reparation. Fourcroy and Vauquclin advanced, that litmus is natiu'ally of a red colour, and that it is made blue by the addition of carl)onate of soda to it. But Mr Smithrion has shown that this is a mistake.! There can be little doubt that the substance to which litmus owes its colour and its dyeing properties is erythriu, a matter which exists in archil, and which will be described in a subsecpient Sec- tion of this Chapter. But we do not know what variation in the manufacture gives to litmus a blue colour, while archil has a red. * Truite de Cliimic, vi. 110. •|- riiil. Tn\ii«. 1818, p. 110. % LITMUS, OR TURNSOLE. 385 evuleo- (tash of solution . The ,er from )lved in 3 a very the blue lution of rtrate of the blue of potash •V that it t%\igotate attaches nixture of iition may elf on the le by the d, and the Id in small ud friable, n from the at present V collected k'ed in the led through Ind left for licts on the 10 colour is in the first [r employed luld hardly ] Fourcroy [red colour, soda to it. Ilitiuus owes Itter which (^ucnt Sec- tion in the has a red. 1. 1 iO. It is known, however, that archil becomes deeper coloured by keep- ing ; and that when old it assumes a blue colour, almost as fine as that of litmus. The erythrin in this case undergoes a notable change, for it is insoluble in water, while the blue colouring matter of litmus dissolves readily in that liquid. The colouring matter of litmus is soluble in water and in alcohol. It has not yet been obtained in an insulated state. The concentrated infusion of litmus has a purple colour ; but it stains paper of a beautiful blue. Acids change this blue colour to red, and alkalies restore the original blue colour without changing it lO green. Hence it difiers in its nature from the juice of red cabbage, the blue colour communicated by the petals of the violet, the blue from the skins of radishes, and, indeed, most blue vegetable colours. Chevreul informs us that the blue of litmus is naturally coloured red by an acid at present unknown, with which it is in combination. When the chloride of barium is poured into the infusion of litmus, there is formed, he says, a blue precipitate, which, after being washed and treated with a quantity of sulphuric acid, less than what is necessary to saturate the barytes, we obtain a red acid liquor which contains no sulphuric acid. The weakest acids, even sulphuretted hydrogen, have the pro- perty of reddening litmus. Hence its value as a reagent to indi- cate the presence of acids, which it does with more delicacy than any other re.-igent with which we are acquainted. When infusion of litmus is mixed with a solution of sulphuretted hydrogen in close vessels, and kept for several days exempt from the contact of the atmosphere, the colour disappears ; but it appears again if we expose the mixture to the atmosphere, or raise it to the boiling point. The infusion of litmus is rendered colourless also by sul- phurous acid, or the hyposulphites. It is obvious from these facts, that a certain analogy exists between the colouring matter of litmus and indigo. Both are capable of being deprived of oxygen ; and when thus deoxidized they lose their blue colour, which is again restored by those substances, as atmospheric air, which are capable of supplying the oxygen that has been subtracted. M. Desfosses informs us that this deoxidizement of litmus may be accomplished by the protosalts of iron. He assures us that when the infusion of litmus is mixed with a small quantity of protosulphate of iron, and some ammonia added, the liquid becomes colourless on standing, while the iron is peroxidized. On exposure to the air the blue colour is again revived. When too large a quantity of protosulphate of iron is used, the deoxidized litmus precipitates white along with the oxide of iron when ammonia is added. If we wash the precipitate, and then mix it with water, and decompose it by means of sulphuretted hydrogen gas, sulphuret of iron is fc/rmed ; but the deoxidized litmus does not dissolve till we digest the sul- phuret in ammonia. If we evaporate the ammoniacal solution, the It is soluble in water, but does not dis- 2 c 1 colouring matter remains. 386 COLOURING MATTKUS. ' .1.1 solve in stronjf alcohol. When burnt it . The alcoholic solution is evaporated to the point t)f crystallization. 7. The crystallized madder-purple is again dissolved in hot alcohol, and crystallized a second time. It is now a light crystalline pow- der of a heautiful orange-yellow colour. It imparts to cotton, impregnated with the alum mordant, a deep reddish-brown purple colour, when it is emploved in excess. Hut if the cotton he in excess, the colour is hrigfit red. A boiling solution of alum forms with it a cherry-red li(piid, which is not altered on cooling, if the purple-red be not in excess. Caustic ])otash forms with it a fine cherry-red colour. Carboiuite of soda forms with it a cherry-red solution, not altered by potash. Sul- phuric acid acq\iires from it a bright red colour. When cautiously heated in a glass tube, madder-purple melts into a dark brown viscid liquid, from which a va])our proceeds, which does not collect in the form of needles, but forms a brown- red viscid mass on the sides of the glass. By the additioil of more heat, it may be driven along the tube, but is then decomposed, be- ing covered with carbonaceous matter. In })ure water it dissolves, and forms a dark pink-coloured li(|uid. In cold water it is little soluble ; but when a hot solution is allowed to cool, it de])osits no Hocks. If the water contain lime, the madder-purple dissolves at first ; but a portion of it combines with the lime, and jjrecipitates in the form of a dark red gum. Hence, if we use in dyeing with madder-purple water containing lime, the loss of colouring matter will be very great. Spirits, alcohol, and ether, dissolve madder-purple very readily, and form orange-yellow solutions. After the evaporation of the liquids, the nuidder-purjjle remains in the form of a bright orange- yellow crystalline powder. When water is added to a hoc concen- trated solution of madder-purple in spirits, a quantity of silky crystals is separated, whidi swim in the solution. Dilute acids, when boiling-hot, dissolve madder-purple, forming a yellow solution ; on cooling, the purple separates in orange-yellow flocks. Ammonia forms with madder-purple a beautiful bright red solu- tion, which, when printed on cotton not i'nprcgnated with a mor- dant, and after drying, being washed in hot water, leaves a clear pink colour. When printed on cotton, impregnated with alum mordant, and washed in hot water, a clear red is obtained. Potash dissolves madder-purple, forming a fine cherry-red coloured liquid, and gives to unmordanted cotton, after clearing with hot water, a pink colour. With mordanted cotton, a dark-red colcur is obtained. 2. Madder-red (the alizarin of R-^biquet and Colin) is obtained separate from madder-purple, in or equence of its insolubility, in a >'Al)OKu. melts •trung alum ^olm'ion. kh '^^'^ 5o^rttr^r-t-*^ .i; •l«rk ora,,j;e<;„|„i J," " n " f .'"^tuto, nwdd,.r.r,.,l ...d,, !„, iZ"S"!~ -E T?;eJ;[."" ■"■■"—"«,- . C;s Ll:f ,ri",' "■ ^^^' * """"'"> -'■ ^"^^ Ammoma forn.s will, m., t ' M« separate. '""' wh. when pri„.ea onuZforl^LVc -""''"'. ■'"^'''°-"'' ""•"'■>"• mlT; ""'«■•• '""« ■■> dark rll ?" ""''."^ed (after dry! ™ ton nnprcgiiated with .p,' ^i "'' ""'"U"- "'ithout lustre 'L Seaiu^T''. '"^ d^-i eVtddrS"'- ■'/■"P-tsadull.r u" ifef : ^1 394 COLOUllING MATTERS. !!■: : It makes the colour considerably darker and redder. The best proportions are 132 parts of clay, 1 part of madder-red, and 22 parts of cloth. The addition of chalk is decidedly injurious. 3. Madder-oraufje is distinguished from and separated from madder-purple and madder-red by its little solubility in spirits. To obtain it let madder from the Levant be well washed with pure water, and then macerated for 1(J hours in 8 times its weight of water. This brown-coloured infusion is then to be strained through muslin, and its place supplied by fresh water. This should be left for It) hours in contact with the madder. It should then be strained and mixed with the tirst infusion. After from 4 to 6 hours re"i'/i.', the liquor should be poured olf the sediment, and the madder-orange separated by liltering through fine paper. The liquid exhibits on being stirred a quantity of small crystals of madder-orange, which remain on the filter. These should be well washed with cold water, afterwards boiled with spirits, and the solution filtered while hot. From this solution madder-orange separates on cooling. The pre- cipitate is to be washed with spirits till it dissolves in sulphuric acid with a fine y .;Uow colour without any mixture of red. As a test of its purity we may impregnate cotton with the tin mordant, and dye it by means of madder-orange : if the dye-stuff has been pure, the colour will be a fine nankin. It imparts to mordanted cotton a bright orange colour when in excess, but paler when the cotton is in excess. Boiling solution of alum forms with madder-orange a.i orange-yellow solution, which on cooling deposits a little colouring matter. Madder-orange^ when heated in a glass tube, exhibits the same characters as madder-purple ; but with this difference that the vapours disengaged are yellow, and condense into a yellow-brown mass. If this is heated again, the same phenomena appear as with madder-purple, and some charcoal is left. Caustic potash produces a dark rose-coloured solution, while carbonate of soda affords an orange-coloured liquid. Sulphuric acid produces an orange-yellow colour. With pure water madder-orange, by the addition of heat, forms a yellow-coloured solution. On cooling some deposition takes place. In cold water the colouring matter is little soluble. When the water contains lime the solution is reddish ; and its dyeing power is diminished or destroyed altogether if the quantity of lime be large. Ether dissolves madder-orange readily. When the liquid is evaporated, the dye-stuff' remains in the form of a bright yellow crystalline powder. Cold spirits dissolve it sparingly. Boiling spirits form a bright yellow solution, from which on cooling the greater part of the madder-orange is deposited. If water be added to a hot solution in spirit, small crystals separate, as with madder- red and madder-purple under the same circumstances. Dilute acids form with madder-orange a yellowish-coloured solution : on cooling the greatest part separates. Liquid annnonia forms a red-brown solution, from which, on evaporating the annnonia, c best lid 22 I from spirits. Lh pure ight of :lirough I be left strained re">''.^' > :_orange dibits on e, wiiicU id water, bile bot. Tbe pve- sulpburic A. As a mordant, bas been r wben in solution of ion, wbicb 5 tbe same tbat tbe ilow-brown ar as witb 1 produces atfords an o-e-yellow it, forms a ikes place. I Wben tbe l(T power is %e large, liquid is Igbt yellow Boiling tooling tbe ir be added Itb madder- Lb-coloured [d ammonia |e ammonia, MADDER. 395 orange-yellow flocks separate. When printed on cotton, impregnated with alum mordant, a dull orange colour remains after washing the cloth in water. Potash ley forms with madder-orange a dark red- coloured solution, which by exposure to the light becomes orange. When printed on cotton, impregnated with the alum mordant, the result is not superior to that with the anmioniacal solution. .'30 parts of alumed cloth require for saturation 1 part of madder- orange. It requires therefore the greatest quantity of cloth for saturation of all the madder dyes ; madder-purple requiring only 16, and madder-red 22 parts of cloth for saturation. Clay has a stronger affinity for madder-orange than alumed cloth has. Hence the reason of the bright orange-yellow which clay assumes when added to the madder dye. And hence the reason why it improves the red colour of madder. It removes, if added in sufficient quantity, the nmdder-orange. 4. Madder-yellow is characterised chiefly by its great solubility in water, and its want of disposition to combine with cotton impreg- nated with the alum mordant. The Dutch madder is especially rich in madder-yellow. It may be separated by digesting 1 part of Dutcli madder in 16 parts of water. After the digestion has continued for 12 hours, let the solution be boiled and mixed with an equal volume of lime water. In 12 hours a dark red precipitate is formed, which besides madder-yellow contains the other consti- tuents of madder, especially madder-orange and madder-purple. To separate these an excess of acetic acid is added to the precipi- tate, which dissolves the lime and madder-yellow, and leaves a red mass which nmst be separated by filtration. The madder-yellow mixed with acetate of lime is still rendered impure by the presence of some madder-purple. This is separated by boiling the solution with cotton impregnated with the alum mordant as long as it is coloured red or orange. A point is at last attained where the cotton acquires a bright rust colour, and the yellow liquor on evaporation, leaves not a brown-red, but a bright yellow residue. The colouring matters are then completely separated. The yellow residue is now dissolved in spirits, and the madder-yellow precipitated from its solution by means of an alcoholic solution of acetate of lead. A scarlet-red precipitate falls, which is to be edulcorated with spirits, then dissolved in water, and precipitated by sulphuretted hydrogen, by which means the madder-yellow is separated from the oxide of lead. Since cotton impregnated with alum mordant acquires only a dull nankin colour by the addition of madder-yellow, and is a very inferior dye, it is needless to dilate at any further length upon its properties. 5. Madder-broivn, not being of any value as a dye-stufl\, its pro- perties have not been investigated with any attention. The great use of madder is to dye cotton cloth red : and by far the finest red of all is what is known in this country by the name of Turkey-red, or Adrianoplc-red. The method of dyeing in this manner was discO' ered in India, and continued long in the undis- I • I ii \ i li 396 COLOUUING MATTERS. Si ''J. i i turbed possession of the dyers of that extensive country. But it gradually made its way into other parts of Asia, and becoming known in the dominions of the Turks, was carried into Greece, and naturalized in their European dominions. In the year 1742, MM. Ferquet, Goudard, and d'Haristoy, brought a party of Greek dyers into France, and established a Turkey-red dycwork at Dar- netul, near Rouen, and at Aubenas in Languedoc. Other esta- blishments gradually arose, and in 1765, the French government, convinced of the importance of this method of dyeing, made the processes known to the public. Many establishments were formed in various parts of the kingdom. But it appears that the only suc- cessful ones were those at Rouen. From France the Turkey-red dye gradually made its way into Alsace, Switzerland, and different parts of Germany. The first Turkey-red work in Great Britain was established about 50 years ago in Glasuow by M. Papillon, who commenced dyeing Turkey- rod in partnership with Mr Macintosh. He made an agreement with the commissioners and trustees for manufactures in Scotland that the process was to be by them published for the benefit of the public at the end of a certain term of years. This period having expired in 1803, the trustees laid a minute account of the diflferent processes before the public. Since that period Turkey- red dyeing has been conducted in Glasgow, and probably also in Lancashire, on a very extensive scale. The number of dyers has become considerable, and the fineness of the dye has been generally admired. For an account of the different processes, as executed in India, Greece, Bucharia, Germany, and France, the reader is referred to Leuchs' Traite complet des Matieres Tinctoriales, vol. i. p. 305, where they are detailed at length. It will be sufficient if the pro- cesses at present followed by the most skilful Turkey-red dyers in Glasgow be stated as concisely as is consistent with clearness. The different steps of the process are as follows : — 1. The cloth is steeped in a weak alkaline ley to remove the weaver's dressing. This is technically called the rot steep. From 4 to 5 lbs. of caustic potash are generally employed for every 100 lbs. of cloth. The temperature of the solution is from 100° to 120°. The cloth is kept in the steep for 24 hours, and then well washed. 2. From 7 to 10 lbs. of carbonate of soda are dissolved in a suf- ficient quantity of water to keep the cloth (always supposed to be 100 lbs.) wet. In this solution the cloth is boiled for some time. 3. It is upon the third process that the beauty of the colour depends more than on any other. Without it the dye cannot be produced on new cloth. But when old cotton cloth that has been frequently washed (a cotton shirt for example) is to be dyed, this process may be omitted altogether. A liquor is composed of the following ingredients : — 1 gallon Gallipoli oil, !. But it becomin<^ reece, and 742, MM. of Greek rk at Dar- •ther esta- ivernment, made the ;re formed i only suc- 'urkey-red d different istablished ommenced He made nufactures ed for the irs. This account of d Turkey- 3ly also in dyers has I generally [ in India, s referred i. p. 305, f the pro- id dyers in clearness. emove the ip. From every 100 n 100° to then well d in a suf- )sed to be ne time, the colour cannot be has been dyed, this MADDER. 393 ffravitvoff^-7i- ""'^^^'^ amount to 29 n^^' "^ ^"^^ water to prevent ubliScofT'"'' ^"^ ^^ ^ept ll^l^^'^' '^^^'"^^'«al machinery fe'> ^3^ Y^^^en levers T^^t "\ "^•°'^°" (*" trou-h in wli.,;- T""^ '^ conveyed bv Hn • ""'^ ^" ^^ by impregnated with Z.<\ \ ^°"«er the doth is allnl i ! ""'"^^ ^« toen days is the In,«. ^''^\ ^'^ better does it t Af.? *" ''•^^ain remain.^ '"'" ^'^'^^^ P«nod that this imnreln^H • ^^.'- ^°"r. The sheen dun. • •"P^'effnation ,s allowed to 'Materially to'assist^lfe'bli' "^^^^ '^ ^'^^^ colour and i f . subjected. It i^ ^L ^f .^^^"? Process, to which -'t t fft ' ^^""^ especially when the cloth i, 1"''^'^^^, '^^ rapidit; oV he It^^' ^-ent operations. ^^ ^P-ed on thJgraJs between Xdl' 4. in favourable weathnr f j , , \ g-a on Gallipoli oil "^"= substances :_ In this hquid the cloth is so^L."'" "P ^^^"^^ "'hole to 22 . n . The cloth thus impreX .ff^- •''' '^ ^^« ^"n that of No^ ^^"""'- „ "• The cloth i, 3,ee„ed i„ • "^ *'"'' '- /pec fie gravi., ■•S?1„-V«?'^r '!{ f ?-' -^ -d soda of '•"'^■'"""e^-e.o bo boiled for 398 rOLOUniNG MATTERS. 1 ' '* ., four or five hours in 25 jLijallons of water, till the bulk is reduced to .about 20 gallons. This liquid, after straining, is strong enough to impregnate 100 lbs. of cloth with the requisite quantity of natgalls. Of late years, sumach from Sicily has been substituted for nutgalls ; 33 lbs. of sui.'iach being reckoned equivalent to 18 lbs. of nutgalls. Sometimes a mixture of 9 lbs. of nutgalls, and l(Ji lbs. of sumach, is employed. In this liquor, heated to 80° or 100°, the cloth is fully soaked. The sumach gives the cloth a yellow colour, which serves to im- prove the madder-red, by rendering it more lively. 1 1. The next step is to fix the alumina on the cloth. This step is essential, because without it the madder dye would not remain, but would be washed off by water. In this country alum is used by the manufacturers, but in many parts of the continent acetate of ahnuina is employed. To form the alum liquor of the Turkey-red dyers, to a solution of alum, of the specific gravity 1*04, as much pearl ash, soda or chalk is added, as is sufficient to precipitate the alumina contained in the alum. Through this muddy li(|uor (which should have a temi)erature from 100° to 120°) the cloth is passed, and steeped for 12 hours. The alumina is imi)ibed by the cloth, and unites to its fibres. 12. The cloth thus united with alumina is stove dried, and then washed out of the alum liquor. 13. These essential preliminary steps having been taken, the cloth is ready to receive the red dye. From 1 to 3 lbs. of madder, reduced to the state of powder, are employed for every pound of cloth ; the (juautity depending upon the shade of colour wanted. The cloth is entered into the boiler while the water is cold. It is made to boil in an hour, and the boilinjT continues for two hours. During the whole of this time the cloth is passed through the dyeing liquor by means of the winch. For every 25 lbs. of cloth dyed, one gallon of bullock's blood, is added. This is the quantity of cloth dyed at once in a boiler. The addition of the blood is indisjiensable for obtaining a fine red colour. Many attempts have been made unsuccessfully to leave it out. It seems probable that the ooU uring matter of blood is fixed on the cbth. Its scarlet tint would doubtless improve the colour of madder-red. 14. Madder-hrown, by this process, is fixed on the cloth as well as madder-purple or madder-red. This gives the cloth a brownish- red and rather disagreeable colour, liut the brown colour not being nearly so fixed as the red, it is got rid of altogether -by the next })rocess, which is known by the name of the clearing process. The cloth is boiled for 12 or 14 hours in a mixture of 5 lbs. soda, 8 lbs. soap, and from IG to 18 gallons of the residual liquid of No. 9, with a sufficient quantity of water, liy this boiling, the brown colouring matter is mostly removed, and the clotii begins to assume the fine tint whicl- characterizes Turkey-red dyed cloth. It is still fiirther improved by the next process. be the gaii '^i AUCHIT, AM) CUDHEAR. 399 iccd to i\o;h to itgalls -, utgtiUs. lumacb, soaked. i to im- nus step remain, in many To form alum, of is added, the alum, iture from irs. The ,, and tlicn taken, tlie owdev, are iiding upon the boiler IV, and the Ills time the the winch. 's blood, is ilcr. T^c red colour, it out. It Ixed on the colour of I dyed < 15. Five or six pounds of soap, and from U) to 18 ounces of protochloride of tin in crystals, arc dissolved in wjitcr in a j^lobular boiler, into which the cloth is put. The boiler is then covered with a lid which fits close, and the boiling is conducted under the pres- sure of two atmospheres, or at a temperature of 250°|. The boiler is furnished with a safety valve and a small conical pipe, the ex- tremity of which has an opening of about ^D^hs of an inch in dia- meter, from which there issues a constant stream of steam during the operation. The salt of tin is found materially to improve the colour. Probably the oxide of tin combines with the oleaginous acid of the soap (fixed in the cloth). This insoluble soap doubtless unites with the red colouring matter of the madder, and alters the shade. 16. After all these processes, the cloth is spread out on the grass, find exposed to the sun for a few days, which finishes the clearing. Such is a sketch of the Turkey-red dyeing, as practised in the principal works in Glasgow. Many attempts have been made to shorten these tedious processes, but hitherto without success. The impregnation with oil, or rather soap, is essential. If one, two, or three immersions be omitted, the red is inferior in proportion to these omissions. Doubtless this soap combines with, and remains attached to the cloth. And the same remark applies to common soap. Cloth bleached by means of chlorite of lime does not produce a good red. Doubtless the fibres of the cotton wool combine with lime, or rather with sulphate of lime, which by decomposing the olea- ginous soap, prevents it from combining with the cloth. But cloth bleached by the old process ; namely, boiling in ley or soap and exposure to the action of the sun, answers perfectly. The colours would be as good without the galls as with them. But there would be considerable difficulty in sufficiently impregnating the cloth with the alum liquor, without its being previously passed through the gall decoction, especially if the cloth be in the least degree greasy. SECTION II. OF ARCHIL AND CUDBEAU. Archil, distinguished in France by the name of orseille, is a dye- stuff prepared originally from the parmelia roccella, a lichen which is found in the countries bordering on the Mediterranean ; but the finest quality came from the Canary Islands, which, however, have been so long resorted to for that peculiar lichen, that it has now become so scarce and so high-priced, that these islands no longer furnish the requisite supply. If we believe Tournefort, the use of this lichen, as a dye-stufi", was known to the ancients. It was the substance employed in dyeing what was called the piirple of A morgos, one of the Cyclades, where tunics, celebrated for their colour were dyed, and sold under the name of amorgis. Tournefort informs us that when he was in the island the lichen was still collected, and sold for ten crcwns the hundred weight.* • Tournefort's Voyage, i. 24S. English Translation. ' I U' 400 COI.OITIING MATTERS. If! W ;■ rl 1 1 After tlio extinction of the Roman cujpire, the method of dyeing" by means of this lichen was h)st. Hut abont the beufinninj; of tlie fourteenth century, a Florentine, named Federijj;o, discovered acci- dentally the tinginjif ju'operties of this lichen while in the Levant- He established a manufactory of archil in Florence, and realised so lar of Oricellarii (from the dye- stuff), which was «fradually chanjjed into Hticellarii and Rucellai. For more than a century Italy possessed the exclusive manufactory of archil. The lichen emi)loyed was collci^ted on the shores of the islands in the Mediterranean. When the Clanary Islands w(^re dis- covered, in 1 402, the lichen was collected in them, and more lately in the C'ape Verde Islatuls. The lichens from these islands furnished a j^reater cpiantity of (M)louriniif matter than those in the Mediter- ranean, because they had reached their full fjrowth. Of late years the parnu'lia roccella has become scarce and bijTli- priced in the Canary and (>ape Verde Islatuls. I lence the supply is brought from other places ; and there cannot be a doubt that various other lichens are employed in the preparation of archil. Rerthollet, who has coi)icd Ilellot, who again copied Micheli, has given the following description of the nu)de of preparing it : — The plant is reduced to a fine ])owder, which is aftei'wards passed through a sieve, and slightly nu)isteued with stale urine. The mix- ture is daily stirred, each time adding a certain cpiantity of soda in powder, till it accpiires a ch>ve colour. It is then put into a wooden cask, and urine, linu? water, or a solution of sulphate of lime (gypsum) is added in sufficient (piantity to cover the mixture. In this state it is kept ; but to preserve it any length of time, it is necessary to moisten it occasionally with urine. I havr had an opportunity of seeing the nuide of j)reparing archil, but from my knowledge of the mode of making cudbear, which is an analogous dye-stuff, I suspect that the above description of Micheli is not ac- curate. What is called in this country cudbear, and in Germany perftio, is prepared from the kconorn tartaren and parmclin oniphahuhfi, by a process which is, doubtless, similar to that employed for making archil. The lichen is steeped, and left for some time in flat vessels, moistened with the liquid annnonia. This ammonia was at first obtained from putrid urine by distillation. But it is now j)rocured by distilling the aqueous li(|uor which is obtained during the pro- cess of manufacturiniT coal ""as for lighting the s*^^reets. When the purple colour is sufficiently developed the whole is dried in the open air, and reduced to a fine powder. This manufacture was begun at Leith, about the year 1777, by the late Mr Macintosh of Glas- gow. The manufacture was first started at Leith, under the management of Dr Cuthbert Gordon. It was from this gentleman's name that the term cudbear (at first Cuthbert) originated. Leith was found an improper place for the manufacture, mv Macintosh, therefore, transferred it to Glasgow, where it is still carried on by .-r«ii " 1(1 of (lycinpf ininj; of tlio iiverod ac.ci- tlio Loviintr I rcjilisod so ir.st fiiinilles )iii till! (lye- 1(1 HuC.(!llfU. iijinufactory lores of tlic la won? dis- iiioro liitelv lis furnished 10 Moditcr- ■e and liijTli- } tlio supply doubt tliat f aiTliil. cd Miclicli, arinu^ it : — lards passed . The mix- y of soda, hi to a wooden ate of lunc lixture. In f time, it is e never had )ut from my 1 analogous li is not ac- ny persw, is a lodes, hy a for making Hat vessels, was at first >w jirocured ig the pro- VVhen the in the open ! was begun >sh of Glas- under the gentleman's ted. Leith Macintosh, rried on l)y <^'I..ir pr of ■^'HMUL AN,, c,;,,„,,„. ;!'■''•'«'« Jvra(inf„.si, i,:,„ , ,, 4oi I">'<'"J'itate was ( L'l , • i" J'"^^''^''"' ''Hvi„ f , '^'l'»«'ted impure with ivory-bjt.k «,,''''' ''"t alcohol, ,u,d L T "^'^ "'"^""r. This , ^f- 'Heeien L fv?n ''^ T'"'^ ^^^"'t^- '"^^ *''« ^°«'"'l ^°'- «ome time / ^-f"^'*^ «^^'»"centrated 1 """"''' •'-i'o^ »"'' jrura to the li„„i,i ,|,°'-"'- J 'w ervtlirin instant „ • ° " « 't is ])re(' I) tjiffvl ;?, 'i'; '^'""» e the ervthrin ;., • ^" "^ "en we A' ? temp'erlw ; r'^- "1'' " 1-«itu\c ffl rff '?""•, ' -■" '"!""!. "■hid, bo,.om., ,"''°™ ^'2° it melts n,^ ".""'' "■"<■■"• ,™*d still l,i„|,eA", ft K ''■'""' '"•i"!'-' on eooi,," u '••™*'l'»'-<.'nt "•^.V conclude th.nt „nCL TT-'" ™" ''» observe '« ""''•'"'• 2d I i ' If !l \i ,1 : f 402 ('()T.()lIIUNe al, cvapo- ammonia. colouring I the solu- .er. The has a fine le solutions ,t precipi- ,lour more It 'iis- I It is easily a mixture Ly the yel- AnCHlL AND CUDHEAll. 403 oxidlzcment : for it takes piace equally under olive oil or on mer- cury. When we digest the parmelia roccclla in boilinjuf alcohol, and treat the alcoholic solution as if we were going to ])rei)are erythrin, the liquid filtered boiling-hot, after being mixed with chalk, deposits, after some hours, a slimy sediment. If we heat this deposit with a small quantity of the liquid it dissolves almost completely, and is deposited again during the cooling of the liquid (which must be filtered while liot) under the form of fin .,rown crystals, which nuiy be whitened by digestion in alcohol with animal charcoal. This substance is the result of the action of boiling alcohol on erythrin, and seems to come in place of the bitter of erythrin, for it is impossible to transform it into that substance. Ileeren has dis- tinguished it by the name oi pseudo-erythrin. It is snow-white, and has the form of scales or flat needles, some- times an inch and half long. It is little soluble in water. Alcohol dissolves about a fifth of its weight of it at 32°. It melts when heated a little above 148", and while in fusion resembles a colour- less oil. On becoming solid it assumes the form of crystalline scales. With acids and alkalies it exhibits the same phenomena as erythrin, with this difference, that it does not yield any hitter priv- ciple ; and that when exposed to the joint action of ammonia and air, it is very slowly converted into the wine-red liquor. According to Liebig, its constituents are : — Carbon 60*00 or 20 atoms = 15 or per cent. 61*07 Hydrogen 6-33 ov 12^ atoms = 1-5625 — — 6-36 Oxygen 33-67 or 8 atoms = 8-00 — — c<2-57 100-00* 24-5625 100-00 It appears from the observations of Robiquet,t that the variolaria dealbata is frequently employed in France in the manufacture of archil. This induced him to subject that lichen to an elaborate analysis, the result of which may be stated as follows : — The lichen was dried and pulverized, and digested in boiling alcohol successively, till every thing soluble in that menstruum was taken up. The alcoholic solutions filtered while hot let fall, on cooling, crystalline flocks, which have no connection with the colour- ing matter of the lichen. The alcohol was distilled off till the residual liquid was reduced to the consistence of an extract, which was triturated in a moi tar with water, as long as that liquid con- tinues to dissolve any thing. The aqueous solution, being reduced to the consistence of a syrup Jind left to itself in a cool place, let fall, after an interval of fiome days, long brown brittle needles. These were freed by pressure from the mother water, redissolvcd in water, digested with ivory-black, and crystallized a second time. The new-formed crystals had a yellow colour. They may be rendered still purer by redissolving them in water, • * Poggendorf *s Annalen, xxi. 33. t Ann. de Chim. et dc Pliys. xlii. 230. I' J I i I. ', 1 il •I'.l i .1 t I - « '! Ji 404 COI-OUniNG MATTKHS. •ill i I precipitating tlio s(»lution by moans of diacctato of locad, wasliini^ tliu precipitate, (liti'nsin;^ i^ in water, and tlirowinnf down the lead l)y a current of sulpiiuretted liydrojijen^ The filtered Tupiid now yiehU colourless crystals, which have the shape of flat four-sided prisms terminated by a bihedral summit. This is tlie substance which furnishes the colourint; matter of archil, and which Robiquet has distinfijuished by the name of orciti. Its taste is sweet, and at the same time disafi^reeable. When heated it melts into a transparent liquid, whicli may be distilled over unaltered. It is soluble both in water and alcohol. Nitric acid causes it to assume a blood-red colour ; if we continue the action this colour disapj)ears, but no oxalic acid is formed. Diacetate of lead precipitates it completely from its solution. But the characteristic ])roperty of orcin is, that when exposed to the joint action of ammonia and air, it becomes of a deep-violet colour. To obtain this colour in its most beautiful state, certain precautions are necessary. When di;^ested with potash or soda, and exposed to the air, it becomes of a reddish-brown colour. If we dissolve it in ammonia and then expose it to the air, the colour which it acquires is not so dark, yet it is not beautiful. But if we expose it to the action of air loaded with ammoniacal fumes, it acquires by degrees a violet colour. To obtain it in this state, the orcin, in fine powder, is put into a capsule, beside another open vessel containing ammonia, placed in a water or mercurial trough, and the two are covered by a class jar. As soon as the orcin has become dark-brown it is removed from below the jar, and the excess of ammonia which it has imbibed is allowed to exhale. As soon as it has lost its ammoniacal smell it is dissolved in water. When a few drops of ammonia are added to this solution it assumes a beautiful reddish-violet colour. Acetic acid precipitates the red colouring matter of the lichen from this solution. Sulphuretted hydrogen deprives it of its colour ; but the colour appears again if we satu- rate the sulphuretted hydrogen with an alkali. To the substance into which orcin is converted by the joint action of oxygen, ammonia, Jind water, Robiquet has given the name of orcein. He considers it as orcin united not with ammonia, but with the elements of that alkali, and indebted to these elements for its colouring powers. The oxygen seems only to commence the com- bination, and the moisture is necessary merely to enable the am- monia to act upon the orcein. Orcein is but little soluble in water, but dissolves readily in the alkaline leys.* Robiquet conjectures that the origin of the other colouring matters may be similar to that of orcein. Tims indigo in the leaves of plants is probably a colourless soluble substance, which becomes coloured and insoluble by combining with the elements of ammonia. When the alcoholic decoction of the lichen is evaporated to dry- ness, and the residue treated with water, it yields orcin. When the • Ann. dc Chini. ct de Phvs. Iviii. 320. rr the l)y a wbich it baa When ;d over ic acid I action Btate of ioseil to ;p_violet , certain oda, and .. If we le colour But if we fumes, it state, the ther open al trough, orcin has the excess s soon as [/hen a few [V beautiful colouring hydrogen [if we satu- loint action ^le name of a, but with Ents for its fe the cora- ble the am- \e in water, [ing matters 33 of \>\si(\i& |es coloured |ia. ited to dry- When the KAFI I.OWGn. 405 residual mutter is diyeated in ether, tliat liquid dissolves another substance, to which Ilobi(iuet has given the name of variolin. This substance j)ossessi's the following properties : — It crystallizes in white needles. VVIien heated it melts ; and if the heat be increased a portion of the variolin may be volatilized imaltered, while another portion is converted into an essential oil. It is very soliihle in alcohol and ether. It produces no change upon vegetable colours. When treated with acids or alkalies no coloiu*- ing matter is produced, not even when the action is assisted by the presence f oxygen gas. AccortUng to tlu; jinalysis of Robiquet, orcin is composed of Carbon ()7'x|M»aure to the 8ini, and removed by wasliiii;;. It is used, however, t)cnwioimlly, to ffive a red colour to silk. The metliod is to nuiki; a cold Holution of the red colouring matter in carbonate of potii.sh or 80(hi. The li(|ni(l is inwncdiately iilt(;red, and as \m\v.\\ lemon jnicc bein<^' added as is rc(|uisit(; to throw down the carthamin, the silk cloth is passed thront,'h the liipiid in th(> nsnnl way by the winch. As soon as it has actpiirc*! the reipiisitu shade of coh)ur it is washed and dried. SECTION IV. — OF LOGWOOD. lAtgrvood is the wood of the Iffematoxi/lon Carnpeachiannm, a tree which till containing lucmatin in com- bination. Filter the alcoholic solution, and distil it till what remains becomes of the consistence i)t' ;i ^v rup. This syrup being mixed with some water, crystals bci^in immediately to be deposited. Leave it for 24 hours to evaporate spontaneously, then dei'aut the li([uid portion from ott' the crystals and wash them with a little alcohol. The decanted licpiid being left to spontaneous evajjoration will yield more crystals, and finally remains a thick uncrystalli/able liijuid. If we evaporate this liquid to dryness, macerate tin dry residue in cold water and (evaporate afresh, more crystals are ol)tain- ed, which may be purified like the others by washing them in alcohol. These crystals constitute hccmatin, or the colouring matter of logwood. They have considerable li.stre, and a scai'let colour. Under the microscope they assume the ajq)earance of needles arranged in sphericles. A glass coated with hannatin appears t)range by trans- mitted, and white by refiectcd light. When put into the mouth it is at first tasteless ; but after a certain time a sensation of astrin- * Ann. do Cliim, Ixxxi. 128. I I h! il ! 408 COl.OUHlNC MAT'li;U!^. ■f H f? policy, acridity, luid hittorncss is perceived. Wlieii lieatcd in n retort till it is decomposed it ..;ivos out anunonia, sliowinir that it contains a/ole as one of its constituents. Tlio charry matter re- niaininu; (after every \\\[ug vol.itile has been driven off) amounts to 54 per cent., which, when hunit in the open air, leaves a reaidiu; con- sistinjj of lime and jieroxide of iron, amounting to rather less tiian 1 per cent, of the hannatin employed. Ila'matin requires, to dissolve it, 1000 times its weifas renders it yellow ; and if we keep a solution of lunnatiu, chari^ed with this f^as (for sonu; time), in a corked phial, it loses its colour altoss pleasinjj: to the eye. If ch)th, impregnated witli the alum mordant, be dyed in a mixture of lojjwood and madder, a very fine hrown colour is fixcil upon it. SKCnON V. — OF DRAZIL-VVOOI). nrazil-wood comes to this country both from Brazil and Pcrnam- buco. That from lira/il is said to be the wood of ccnsa/pina sapan^ cmsalpina crista, and cccsalpina vesica ; while that from Pernambuco is the wood of" the ccvsa/pina vr.kinata. These trees are lar'2. 412 coloured matter, water.* COLOURING MATTIillS. Both of these colouring matters arc soluble In SECnON VIII OF HED FLOWERS. The petals of many flowers have a very intense red colour, fre- quently produced by so small a quantity of colouring matter, that it disappears altogether when we attempt to extract it. We find it in general situated in the epidermis of the petals ; the juice obtained by subjecting the petals to ])ressure being generally colourless. The colouring matter of deep red flowers is often rendered blue by an alkali, and yellow or red by acids — in this respect resembling hfematin. The colour of the petals of the papaver rheeas is a lively red. Potash changes it to green, but the carbonates of soda and ammonia are said not to alter it. The infusion of these petals in carbonate f soda or of ammonia is red ; but it becomes green on the addit- u of potash. Some observations upon red flowers were made in the third Sec- tion of the preceding Division. And so little attention has b it a greenish-yellow colour. Sulphated peroxide of iron causes a precipitate, and strikes a green colour with it. Sulphuric acid dissolve"* it, and forms an orange-yellow solution, with a tint of green. Nitric acid, when boiled with it, converts it into oxalic acid. When the aqueous solution of morin is exposed to the air, it im- bibes oxygen, and assumes a red colour. This change does not take place if oxygen gas be excluded. When morin is heated in a retort it melts, assumes a reddish-brown colour, gives out water, and a liquid which crystallizes, on cooling, in yellow needles. It give? out likewise oil and gas, and a light charcoal remains behind. The yellow crystals strike a green instantly with sulphated per- oxide of iron. When we examine the wood of the morus tinctoria, we often per- ceive in it a pulverulent matter, either yellow or flesh-red. This matter, according to Chevreul, is almost entirely composed of morin, as may be ascertained by treating it with ether, which dis- solves it and deposits it in crystals. When the flesh-red powder is digested in ether, it leaves a red matter undissolved, to which it was indebted for its red colour. The ethereal solution is yellow, with a shade of green. When evaporated it leaves crystals less coloured than those of morin ; and if the ether has been applied in sucoessive portions, those of the second washing are less yellow / ■ * Bancroft on Pcnnnnont Colour?, i. 412. f Ann. rle Chim. ct de Pliys. ix.330. X Lemons de Chimic a|>|)li(|ii6i> u la 'IVincture, ii. Levon 30, p. 152. V.'EM). 5 supposes, was called 1)0 cut into r the cloth ic is boiled NJow, if we n a matter ■ is yellow, a rod or ilinl818,t erature. A liich, when solution is ; and when In is depo- in alcohol, tion, dcjjo- itin. Pot- fine yellow >n of alum de of iron Sulphuric with a tint into oxalic air, it im- B does not leated in a out water, sedles. It ins behind, hated per- often per- •ed. This mposed of which dis- ed powder to which it is yellow, •ystals less ap})lied in ess yellow 'liys.i.x.330. ). 152. timn those of the firs^ if '*'^' " 'Cutis r.f ri ^'" "'''"" """'""" precipitate in it u 1 "^f 'P^ ^"'""^ ««Jour. LrZTn ?^^"*'"- with the solution „f • 7^ "!"' """""nt it is comL„? ^"'''' -lied Saxotg^er. '""■*''" '» ''^P'"'- -id ru^t^ 'ZZt grtater abundance. Therp «,.o { ,^. ^®"°^ colour no^ mattp^ ^"d when diluted ^ tl tv If i^''"-^^^"' " '^''^^"i^h-y^ acids render this colour mo •! i ^'^!^''^« '-^ ^h^de of ^rcen tT' f ammoniac renderT deener^^''\^'^ ^'^^'^^«' com^ n'it l^'a •"«.stissS::::;rJ:r:;:: I' i 41(> COLOUIIINO MATTKItS. :| li f luv9 distinguished by thu name oilufeolin. lie obtained it by sub- limation.* It is crystallized in needles, some of which are lonpc, transparent, and of a pale-yellow colour, others short, of a deeper yellow, and havinj? a velvety aspect. It is very little soluble in water ; yet though it fjiA'cs very little colour to that licpiid, it communicates to it the property of dyeing silk and wool, impregnated with the alum mordant, of a fine greenish-yellow colour. It is soluble in alcohol and ether. Solution of potash gives it a beautiful golden-yellow colour, which gradually passes into greenish-yellow, and at last reddish-brown, owing probably to the absorption of oxygen. Barytea water, strontian and lime water, and ammonia, produce similar effects. Acetate of lead, alum, and acetate of copper preciptate the aque- ous solution of luteolin yellow. Sulphatcd peroxide of iron throws it down olive-brown. Concentrated sulphuric acid produces a yel- low colour with a tint of red, and reddish-brown flocks gradually precipitate. Concentrated sulphuric acid dissolves the crystals of luteolin ; the solution is orange-yellow, with a shade of green, and when water is added to the solution a precipitate falls. The yellow colour communicated by weld is more ])ermanent than that connnunicated by quercitron bark, or by old fustic. In calico-printing Bancroft assures us that a heat nearly as high as that of boiling water is necessary to fix the colouring matter of weld, and the parts wanted to be kcjit white are then so much stained by it that the stain is very difficult to remove, f This is doubtless one of the reasons why weld is so little used in this coun- try in calico-printing. Indeed the chrome-yellow has in a great measure superseded vegetable colouring matters in the operations of the calico-printers. SECTION IV. — OF PERSIAN IJERRIES. The dye-stuff known among calico-printers by the name of Per- sian berries is the fruit of a variety of the rhnmnus infextoriiis, which comes to this country from the Levant. These berries are larger than what are called Avignon berries, which are cultivated in the south of France ; though it is believed that both are varieties of the same species of plant. These berries are rich in a very beautiful yellow colouring matter; but unfortunately it is not fast. Hence the use of it of late years, since the discovery of chrome-yellow, is much less frequent than formerly. According to Chevreul, they yield to water among other bodies : — 1 . A yellow colouring matter which is imited to a substance insolu- ble in ether, and very little soluble in strong alcohol ; but very solu- ble in water. Chevreul considers it as volatile. 2. A matter remarkable for the intensity of its bitterness, and which is soluble in water and alcohol. * Lemons lie Cliiinio ai)])!!*!!!!'-!' si la Tcincture, li. 30 Lcyon, p. 144. \ Baiicrolt on Permanent Colonrs, i. 409. pass ml Anot\ of the South the Ead time of] «oon afl this plJ t BoiiJ guage of'l word urtl ANOTTA. 417 sub- irent, , nnd ; yet tea to I ulum Icoliol yellow it last tarytes similar • aque- tlirows i a ycl- adually stals of en, and rmancnt tic. In liigli as lattcr of *o much This is lis coun- a great )crations of Per- fectoritts, rries arc ultivatcd varieties fT matter ; ars, since formerly, odies : — tee insolu- very solu- rness, and 144. 3. A red colouring matter, which exists in only a very small pro- portion in tlie berries, and which has a tendency to undergo de- composition, being changed into a brown substance on exposure to the air. It is found principally in the aciueous extract of the ber- ries, insoluble in ether and alcohol. When Persian berries are boiled for a quarter of an hour, in 1 times their weiglit of water, a brownish-yellow decoction is obtained, having a shade of green. It remains transparent when cold, has a ])eculiar smell, and a very bitter taste, (ielatin causes a slight precipitate in it, which does not fall down immediately. Chloride of b«arium occasions no precipitate. Nitrate of silver, a reddish-brown precipitate, soluble in nitric acid. Oxalate of ammonia throws down lime. Solutions of potash or ammonia change the colour to greenish- orange, without occasioning any precij)itatc. Water of barytes, strontian, and lime, change it to greenish- orange, and throw down some flocks. Protochloride of tin changes it to greenish-yellow, without occa- sioning a precipitate. Alum diminishes the colour, and precipitates nothing. Acetate of lead. 0. Acetate of copper. A slight yellowish-red precipitate. Sulphated peroxide of iron changes the colour to olive-green, without occasioning a precipitate. Concentrated sulphuric acid weakens the colour, but precipitates nothing. Nitric acid of 1*300 weakens the colour without producing a pre- cipitate. An excess of acid develops a beautiful brotvtiish-red colour. Oxalic acid weakens the colour, and throws down oxalate of lime. Acetic acid weakens the colour, and causes a very slight precipi- tate. Iodine water produces no effect. Chlorine deepens the colour to red: a greater quantity makes it pass into yellow.* SECTION V. — OF ANOTTA. Anotta, in French rocou or roucou, is a name given to the pulp of the feeeds of the bixa orellena,] a shrub originally a native of South America, and now cultivated in (iuiana, St Domingo, and the East Indies. It was used by the natives as a dye-stuff at the time of the discovery of America, and was made known in Europe soon after the conquest of Mexico by the Spaniards. The fruit of this plant is a coccus, containing from 30 to 40 seeds, smaller • Chovreul, I. c. p. 174. t Boussingault informs us that the word bixa is drawn from the ancient lan- guage of liayti. Hocon, according to Hinnboldt, is derived from tlie Brazilian word urucct. See Ann, de Chim. et do Fhys. xxviii. 441, 2 E t i 418 COLOt^niNO MATTRtlS. n^r !:li than a poa, and covered with a fjhitinous matter, havinj^ a ver- inillion-rod colour. To extract this coloiirinj; matter, the grains are rasped down, water is added, and tlio whole in allowed to re- main for some days. A sort of putrid fermentation takes place. The whole is then thrown on a drain, and the water which holds the colourins; matter in suspension is collected. The colourinfj matter ffradually subsides. It is taken out and dried in the ^hade. It is made up into small cakes, which come to Europe under the names of anotta and rocou.* This ])rocess yields a very impure matter ; on this account the process followed at Santa- Fe do Bogota is preferable. It consists in rubbinu the firains of the blxa orellana a'jfainst each other under water. Ah the colotu'ini; matter is nuM'cly superficial, it is easily rubbed off without loadinj; the water with the mucil:i rc- mttcr It J9 names nt the )nsist3 i easily matter r being to dry. country geneous "not t\ie becomes i(rrceablc t'softens, r a bulky ,le yellow on, when a beauti- poration, a powder. The solu- [ve anotta 'he acids lot' anotta. I'cmark ap- acid is \e\y a fine [uty, passes ^cording to the same the air, on nnotta, is weak. It comraunicates a green colour, which soon passes into yellow. When a gentle heat is applied, nitrous vdj)ours are given off, the anotta assumes the ccmsistence of a syrup, and some minutes after the whole takes fire, and burns rapidly, leaving a charcoal in the state of minute divisi(m. It dissolves readily in oil of turpentine. The fixed oils dissolve it also. The aborigines of America employ a solution of it in a fixtul oil as a paint, under the name of onoto.* According to Chevreul, anotta contains two colouring matters, the one yellow, and the other red. The yellow colouring matter is soluble in water and alcohol, and slightly so in ether. It gives a yellow colour to silk and wool, impregnated witli the alum mordant. The red colouring matter is very little soluble in water. But it dissolves in alcohol and ether, to whicii it communicates an orange- red colour. It dissolves also in potash ley, and the solution has a deep orange-red colour. It is this colouring matter which has the property of being changed into blue by sulphuric acid, as Boussin- gault first observed.f The price of anotta in France is usually about sixpence a pound. But sometimes it rises as high as half a crown. When this happens it is very common to adulterate it with powder of bricks, colcothar, &c. Til is adulteration is easily detected by exposing anotta (pre- viously dried at 212°) to a red heat till it is quite burnt. If the anotta be pure, the residual matter vill not exceed 13 per cent. Whatever is beyond that quantity is adulteration. t SECTION VI. — OF TURMERIC. Turmeric is the root of the curcuma tonga, a plant, which is a native of the East Indies, and which grows abundantly in Malacca, Java, and Balega. It has been repeatedly cultivated in England. The root, in its dried state, has been long known, and passed under various names, as crocus sativus, terra merita. Externally it is of a pale-yellow colour, wrinkled, solid, ponderous, and internally of a deep-saffron or gold colour. Its odour is somewhat fragrant, and to the taste it is bitterish, slightly acrid, exciting a moderate degree of warmth in the mouth, and on being chewed it tinges the saliva yellow. It has been much employed in dyeing ; but unfortunately the colour which it imparts, though very beautiful, is not fixed. In India it is much used for colouring and seasoning of food ; indeed, it is an essential ingredient in the curry powder, now so much used in this country. The root of the curcuma louffa was examined by MM. Vogel and Pelletier,§ and found composed of 1 Lignin. 2 Starch. , ■ * Boussingault, Ann. y digestiiiff turmeric in boiliiij; alcohol, filteriiijj the Holiition, and evaporatinj^f it to dryness. The residue bein<^ digested in ether, the cnrcumin is dissolved, and the brown- coloured matter left untouched. The ether ht'inadish; the , mercury, occasion a ircuniin. ution has a /\i\fT matter h tour times uliosplioric iui. 'ri>« bd in excess, [of curcuTuin le-rcd matter [)lour— pl^os- he vegetable SAIFUUN. 421 When curcmnin is dlHtillod it givea out a brown oil, water, acetic ucid, carl)urettc(l liydrojrcii, and carbonic acid, aiul leaves a diarry matter in the n^tort. Nitric acid, when conceutruted and assisted by heat, decomposes it.* SKCTION VII. — OF SAI'inON. What is called miffrim, consists of the dried stijjmas of the flower of the crocus satinis, a plant, which is a native of the western parts of Europe. Indeed, it is a native of Kngland, and is abundantly cultivated in (ireat Uritain, iiiul Kn^'lish satlron is preferred to what is imported from abroad, and may be distinguished by its parts being hir,^"" «°we* '" Ss'r-'t,''- -- colo .' ice vert de berries of hich grows ies. This hyllite. Stic potash per tinged irbonate of lour, which ce.t , to which 1818, p. IK). CPIAPTER VII. Of" FIXED OILS. .S^;:sSt;!'tfcr„^t''^"''^««-'''«"-o„stu„ f he tern, salt can be a niod ^ .le"'''"'' "^ '»'° "■■ "><> e "St Tit';! '""/**"' - '0 "esc r^^^^^^^^^ Z *» P'-f-nt im"perfecT ;; '' '""•' '"'' "-■' -^j-^ '» ets tr:s«& * Lriii'lii: 'I',.. .:. - . .^ ■•^ Ul . iirtiic ae» Loulcurs, i. 204. t Le«i., Neumann's Cheniisfry, p. vs-2. ! {( Ml if 428 FIXED OILS. it will })o only from these minute details that general facts can be dijJuced, ^n ord- 1 to form an accurate theory of oily bodies. In Jie Clainistry of Inorganic Bodies (vol -p. 34G), the general characters of the ^tv/d oils have been given, and their constitution ftated, as far as kno',vn. Their division into dryint/ o\ls, fat oils, and solid oils, has been stated, a/ '.I a list of the most important oils belonging to each class has bein g; von. It remains here to enter into some details respecting such of thr- oils belonging to each of these classes, as from their importance seem entitled to particular mention. DIVISION I.— OF DRYING OILS. These oils gradually dry when exposed to the air into a l.ard transparent varnish, which does iMt stain the fingers. The t!\ost important of them are the following : — SECTION I. — OF LINSEED OIL. vipe see lis Is of \i\ hill This oil is obtained by expression from the linum usitatissimum, or common Jlux^ -vhich t'lui :j>h about 22 per cent, of their weight of it. It has a llght-yeiiow colour, and a peculiai smell and taste. It may be cooled down tc 4° without undej g'oin.y' any other change than becom'ng paler in the loiour ; but at - 17'' it congeals into a solid yellow mass. Acconliiig to GurSi:r>w it becomes solid at 3°, provided that temperature Ik; con- tinued for several J ■' s. It dissolves in L lunes hs weigh; of boiling alcohol, end in 40 times its weight of cold alcuh(!!, and in 1*6 times its weight of ether. Unverdorben ha."* pai'ting k« pt, or wlicn it dries. Whi n kept in s ceHar and in a vessel imperfectly shut, it gr.'idually deposits a white, i'atty, soft sediment, and a brownish powder. The fat body is stearin, mixed with a substance insoluble in ether, and possessing tin; characters of vegetable albumen. The solutitm of the stearin in etiier deposits crystals when left to spontaneous eva- poration. This stearin is soluble in 100 times its weight of cold, and 40 times its weight of boiling alcohol. It dissolves in 50 times its weight of cold, and 20 of boiling other. It is very difficult to convii !: this stearin into soap. One-fourth part of the hroivn powder dissolves in water. The solution contains a substance analogous to gum, which is precipi- tated both by the dilute acids and the acetate of copper, and is n< ither soluble in alcohol nor ether. The remaining :^ths of this brown powder are insoluble in most menstrua. The hydrate of potash extracts from it a little resin. To study the substance formed during the drying of this oil, Unverdorben triturated the oil with a sufficient quantity of chalk to render the whole pulverulent, and left it for four weeks exposed in a warm place. At the end of this time the oil was completely dried. The chalk was dissolved by dilute muriatic acid. The residue acts can be ies. the general !onstitution {^^fat oils, [)ortant oils enter into ;h of these ir mention. ito a liard The tnost eils of tivi out 22 per )ur, and a 4° witliout he (. oioiir ; coriliiig to ire Ik; con- and in 40 it of ether, ich this oil t gradually /der. The ether, and solution of neous fva- ht of cold, n 50 times difficult to ter. The is precipi- )er, and is ths of this bydrate of f this oil, of chalk to exposed in tely dried. iio residue OJL op HEMPSEED. toeing treated with ether nn . ' ^^^ the consistence of far ' T» ""^^"""3 matter was dissolvp.l h • ino residue insolnhla • i ««■,' iM rtl';!' ?!/' '* .^"'■ertcd into the mr«;,/, f -"vantage .„ varnishes .„ £^h^C£^ '^ ^^ This -I "'"""'"— »•■ °"- Of IVAMCTS tea grisKr^ bnTwt f"'' f ^'^'"^ ""'"^ when fresh ?;Y|-ps,a„d,.avelta;„': tt°of '/'■? '™« "' bult of TMs oi, i, ll"": "'-"^ •>"• - —- o. ■ «'-, or ,„^. "«tn'Verdr„'ns'''= ^^°f °f-* " it IS greenish-yellow, but * Ann. de Chi,„. et de Ph.s. xlix. 230. I. i\ I k\ 430 FIXED OILS. beconios yellow by keeping. Its smell is disafrrooablc ; but it has I'Uie taste. It dissolves in all proportions in boiling alcobol ; but cold alcohol dissolves only the 30th of its weight. At 5° it becomes thi?k, and at — 17° it freezes like oil of walnuts. It is used for lamps in Russia and other countries ; but it is apt to form a viscid varnish, difficult to remove froir the lamp. It is also used for making soap, and in varnishes. Saussure left hempseed oil for four years in contact with oxygen gas over mercury. Tlie oxygen absorbed was 138*4 times the bulk of the oil. The bulk of the residual gas was 0'2234, or about IJtlis of the original gas. It was composed of Carbonic acid .... 90"7 Azotic 17*8 Hydrogen .... 2()'4 Oxygen ..... 3*() 138-5* • ill . I ' I SECTION IV OF POPPY OIL. This oil is obtained by expression from the seeds of the pnpaver somnifernm. It resembles olive oil in its appearance and taste. Its specific gravity is 0*9249 at 59°. It congeals at zero, or about half a degree lower. It requires 25 times its weight of cold, and 6 of boiling alcohol to dissolve it. It unites in all proportions with ether. In France and Germany it is used as an article of food. SECTION V. — OF CASTOU OIL. This oil, the oleum ricini of the Pharmacopeia, is obtained by expression from the seeds of the ricinus comiminis, a biennial plant, cultivated in the West Indies. It seems to be the x/;c/ or xgorwi/ of Dioscorides,t who mentions that the seeds are powerfully cathartic. When expressed from the seeds cold it is quite transparent, and has only a slight tinge of yellow ; but when obtained by boiling, it has most commonly a deeper shade of yellow. It possesses cohsiderable viscidity. Its specific gravity at 77° is 0*9575, as determined by Saussure. It has no smell, and its taste is scarcely perceptible. It boils, according to Bussy and Lecanu, when heated to 509*^, and may be partly distilled without the evolution of any gas, but emifting a very peculiar smell. When about a third of the oil has been distilled over, gas is disengaged in abundance ; and this gas is in- flammable. VVhen cooled down to zero it congeals into a yellow transparent mass. When exposed to the air it thickens, and be- comes rancid, its colour at the same time deepening. It may be mixed in all proportions with alcohol and ether, and when so mixed it lets fall the foreign bodies with which it may have been mixed. This solubility in alcohol constitutes a remarkable difference between castor and other fixed oils. Bou( tion. Pal ture oalmin ^iquid nielte potas same additio compoi mixed concre Boudc Pah betwee tion. in all diminij its weii * Ann. do Chim. ct de Phvs. xlix. 229. f Diopcorldos lib. iv. c. 1(14. * Jo ; CASTOn OIL. 431 According to Bussy and Lccanu* it f];ive3, when distilled and converted into soap, j)roducts different from the other fixed oils. After a tliird part of the oil has been distilled over, there re- mains a peculiar substance, which is solid at the ordinary temjjcra- ture of the atmo8j)here, and insoluble in oils, alcohol, and ether. Sulphuric, nitric, and muriatic acids scarcely act (m it. But it is dissolved when boiled in a solution of caustic potash or soda. The oil distilled over is colourless, it crystallizes during the cooling, and has a strong smell. This oil is accompanied by two acids, dis- tinguished by their acridity, and by forming with magnesia and oxide of lead salts, which arc very soluble in alcohol. When castor oil is mixed with g^th of its weight of byponitrous acid (diluted with thrice it« weight of nitric acid) it becomes solid in about seven hours. It first assumes a golden-yellow colour, and at last changes into a translucent matter, having the consistence of wax. This change goes on about 8 times slower than with olive oil. The rapidity also is coiniected with the quantity of byponi- trous acid used. When it is only ^'n^^ of that of the oil the solidification re()Mircs ()0 hours. To the solid substance into which castor oil is thus converted, M. Boudet has given the name of palmin.lf Palmin has usually a yellow colour ; but this colour is accidental, pure palmin being white. It is at first of the consistence of wax, but hardens by keeping, and assumes a resinous appeai'ancc. It melts at 151°, though when quite new the melting ])oint is as low as 144°. It has a smell similar to that of the volatile oil obtained by Bussy and Lecanu when castor oil was distilled. But M. Boudet could extract no sensible quantity of oil from it by distilla- tion. Palmin is very soluble in alcohol and in ether. At the tempera- ture of SC}°, 100 parts of alcohol of 0*837 dissolve 50 parts of nalmin. It is much more soluble in boiling alcohol ; and when the Mquid cools it is deposited in small opaline grains. When palmin is melted, ether dissolves it in all proportions. When treated with potash ley it is easily saponified, glycerin being separated at the same time. The soap is soluble in water, but is separated by the addition of chloride of sodium, undergoing at the same time de- composition. When this soap is dissolved in water, and the solution mixed with muriatic acid, an acid is separated, which, on cooling, concretes into a crystalline mass. This is the palmic acid of M. Boudet. Palmic acid when pure, fuses at 122°. It is purified by pressure between folds of paper, and by solution in alcohol and crystalliza- tion. The crystals are white silky needles. Palmic acid is soluble in all proportions in alcohol and ether. But its solubility in alcohol diminishes as that liquid contains more water. It requires 5 times its weight of alcohol of 0*915 to dissolve it at the temperature of I ! I ', Jour, (le Pliarmacie, xiii. 57. t Anil, do Chim. et de Pliys. 1. 413. 432 FIXKI) OII.H. jl'-' 1 Vr 122°. It reddens litmus paper 8troii<;Iy, combines with buses, nnd dccoinj)()Hes the carbonates. I'ldmate of soda is obtained by niixinj^ paluiic acid witli a solu- tion of carbonate of soda, evaporatinjj; to drynijss, and di. 'i'he alcohelic solution of palmate of soda, wlicn cooled, assunu's tln> form of a jelly. This salt does not crystalli/e. When treated with a great deal of water, one-half of the base is removed, and a bipal- niate of soda formed. Palmate ofaynmonia may be obtained in the same way. It does not crystallize. Pa/matt' of inagmnin is soluble in hot alcohol, and is deposited in scales as the s')hiti(m cools. Palmate of lend is soluble in hot alcohol, and assumes the form of a jelly when the solution cools. Hut if the solution bo dilute it deposits silky needles. Palmate of lime is solidde in boiling alcohol. Palmate of copper, obtained by double! decom])osition, has a fine green colour. It is sensibly solidde in ahioliol of 0*8 17. Palmate of silver is insoluble in alcohol and wiiter, but soluble in ammonia. It was analyzed by M. Boudet, who found it composed of Palmic acid Oxide of silver OG-T.') or 2010 32-25 or 14-5 100 ! Ji According to this analysis the atomic weight of palmic .icld vi 29-10. When palmic acid is distilled, about -,"|ths of it passes over in a butyraceous state. It contains a cpiantity of the volatile acid from castor oil obtained by Bussy and Lecanu. . lost of the rest is palmic acid unaltered. When palmin is distilled it gives the same products as castor oil. No palmic acid seems to be formed. Nitric acid and sulphurous acid are capable of solidifying castor oil as well as hyponitroiis acid. The theory of this curious change produced in the oil is still obscure.* Castor oil is well known, and in constant use as an excellent purgative. Its purgative qualities were ascribed to an acrid sub- stance contained in the seeds ; but Guibourt has shown that this acrid substance is so volatile, that it is driven off by the temperature necessary to extract the oil from the seeds. M. Subeixran extracted an acrid resin from castor oil, by the following ])r()cess : — The oil was saponified, taking care not to add an excess of alkali. The soap was dissolved in water, and precipi- tated by chluride of calcium. The ])recij)itate was washed and boiled in strong alcohol. Most of t le soap is deposited as the soJij und and unlij diirii ca.sfc V pn^fo the o very I oil is Tl, fioliiitti oniplny "llcci-tj that it days, 'lets as Oot. <^f wahn. ^Iie thro qualifies Dr N 'ihout ()■( them. I»'oj)erti( ties, 'ij oil is xn{\ to (h'\ iieJ ethrr; „f •i'^-'filied. I The 1, comhiiiini C()mpos(.,i| '"ng is (lif over, J,;, J "arytes wf salt by j,|J •''stilJed ol joints of til 'riieso ol '^"t the solf * Boudet, Ann. de Cliini. ct de Pins. I. 11 1. CROTON Oil,. 433 i\u- n>o 'onu t\\ u doLM oil in form liite it n\)le i» nH)()sed 1(1 w ac ,cr m a •1(1 froi'*. astor oil. i(T castor cluingc excellent •rid 8"li- tliat tills Yperature lil, by tli« lot to add l\ pvocipi- Islied and Id as the solution cools. Tlio a.roliolic solution is evaporated to dryness, and diixested in other. 'I'lit; portion of soap pn^scnt is dissolved, and tlie iirrid resin, in very sniall (piantity, I'-inaiiis.* It is not indikely tluit tlu^ minute (puuitity of rcsiii tlui ,)tained is formed duritiu!' the j)roi'ess. It eaiuiot acroinit for the cathartieiiualities u\' castor oil. 'rh(> oil Is (piite destitute of all acridity. In this (tnnntry, we prefer cold drawn castor oil as a puriiative : in l*Vaiice, they consider the oil obtained by coelien as tlie host. In all likelihood there is very little ditlerenco in their medical (pialities, but tho eold drawn oil is most agreeable to the eye. SKCIION VI. — OF CROTON OIL. Thl.s oil is ohtainc'd by expression from the seeds of the croton /ipliiii/i, a tree which ijfrows in tlu^ I'last Indies. It had been employed in medicine above a century a<;o ; but its action was so nncertaiii, beini; sometimes very vioI(Mit, and sometimes nearly inert, that it was laid aside, hut its use has hw\^ a<:,^nn revived in our own days. A single drop of the oil constitutes a dose, and generally ficta as a sufficient jjurgative. (.roton oil is yellow like iionev, and about the consistence of oil of wahnits. Itssmcdl resembles jalap, its taste is acrid, and irritates the throat. Alcohol and ether dissolve it. It owes its purgative qualities to a portion oi rrntonic m/r/ dissolved in the oil. l)r Nimmo found that wIkmi the seeds were digested in ether, about (iO per cent, of their weight of oil iniuht be extracted from them. Alcohol dissolved '=ds of tluMu, which possessed purgative properties; what remained had litth; taste, and no medicinal (piali- ties. The crotonlc acid may he isolated l)y saponiticati(m. The oil is mixed with magnesia and water, and the mixture evaporated to dr\ uess. The oil is then separated, by digesting the whole in ether ; and the magnesi;i. residu(> is mixed with phosphoric acid and (U.-^rilled. Mut by this process very little acid is obtained. The best method of proceeding is to convert the oil into soa]), by combining it with the reijuisitc portion of potash. The soap is de- composed by tartaric acid, the whole tiltered, and the licpiid remain- ing is distilled in a well luted apparatus. An ac'd liquid comes over, having an acrid and disagreeable odour. Saturate with barytes water, evaporate to dryness, and decompose the barytes salt by ])hosphoric acid in a very concentrated state. The acid is distilled off, taking care to keep the receiver cool, and to have the joints of the apparatus well luted. DIVISION II.— OF FAT OILS. These oils, like the preceding, become solid by long exposure ; but the solid formed has the appearance and properties of tallow. :i : 'i * Jour, (le Pli:iriiincii'. xv. 509. 2 F 434 FIXED Oils. SECTION I. — OK OLIVE OIL. This oil ia oxprcasod from tho pcrlcnrpiiiin of the fruit of tlio olea europcft, or coininon olivis Its iifjuiil colour is a |)ivlo yellow. Ita specilic gravity iit 77° i.s 0*9109, iis (let('rmiiit>(l hy Siiimsuro. It con oU. cent. to\»t a t hav- I pro8- Tivtviro noil liy The (I. i^y ,11 oU of hen tlio u water. v\). %ulk of and hy- irly ^li «f depriving in contact sit. All olive oil, iThc wine, Ivstc. 'r^»« ^lievallier, >aris were U oils. In Institutes a In climates, lat measure lood. What Ipcseed oil. Iiistications. IxUx. 220. I'ontet reconimcnds* the followinj; method for di«roverni;,' the jiro- sei.co of poppy oil : — DJHsolvo () piirtH of inori'ury in 7i parts of nitric acid, of the spe- cific •'rarity, I •3.'). Mix 2 jmrts of this sohition with !)(» j)iirts of the oil to bo tested, and ayituto the niixturo well every half honr, or oftoruT. If the oil was puns \\\v luixtnre in 7 honrs will assnuie the form of a thick maii:ma, and in 24 hoiu's it will liocouu^ ho hard as to oppose resistance to a ^lass rod jjusliod into it. Other lixed oils do not jiossoss this property of conihinin^j^ with nitrate of mer- cury ; and if the olive oil contains any other oil, the whole may be- come thick, but it will never bccouu; solid. If the (piantity of foreijiu oil amount to ^,th, it will separate from the tl ick mass, and form a distinct layer, the thickness of which will depetul upon the (piantity of forcijfn oil i)resont. Should the two oils have been mixed in C(pial 92. t Ibid. :j5 11 43G FIXED OILS. ll ii To tlic solid matter into which olive oil is changed by means of liyponitrous acid, l^oudet has given the name elaidln. It possesses the following characters : — Its colonr is white, or, if yellow, becomes white when digested in alcohol, which dissolves the colouring matter. Alcohol of 0"837 dissolves a very small quantity of it. It has no effect upon vege- table blues. If, after being digested in hot alcohol, it be exposed to pressui e between the folds of blotting paper, it gives out a small quantity of oil, and may then be considered as pure elaidin. Its colour is not altered by potash, ammonia, or sulpholiydrate of am- monia. It melts at 97°. Ether dissolves it in every proportion ; but it requires 200 times its weight of boiling alcohol, of the specific gravity 0'897i^, to dissolve it. The solution, on cooling, becomes muddy, but no crystals are formed. It is easily saponified when mixed with potash or soda ley. Glycerin is evolved, and a fatty acid, which combines with the alkali, and forms the soap. The soap thus obtained is soluble in w.ater, especially when hot ; but assumes the form of a transparent magma on cooling. Muriatic acid decomposes this soap, wlien assisted by heat, and disengages the fatty acid, which appears first as a fluid oil, but on cooling concretes into a solid crystalline mass. The acid thus formed has peculiar properties, and has been called by INI. Boudet elaidic acid. It melts when heated to 111°, and strongly reddens litmus paper. When dissolved in hot alcohol, it is deposited, on cooling, in small pearly very brilliant scales, resembling boracic acid in appearance. Ether dissolves it in all proportions when it is melted. It is also soluble in all proportions in boiling alcohol. At the tem])erature of 97°, I part of alcohol, of specific gravity 0*915, is capable of holding in riolution 5 parts of elaidic acid ; while 00 parts of the same alcohol boiling, is scarcely capable of dissolving 1 part of margaric acid. Elaidic acid may be distilled over almost completely without al- teration. When heated with oxide of copper, it is converted into water and carbonic acid. It saturates bases, and separates the car- bonic acid from the carbonates. If we wish to form neutral elaidate of soda, we have only to heat elaidic acid with a solution of carbonate of soda. Evaporate the solution to dryness, and digest the residue in alcohol of 0*8 17. The elaidate alone is dissolved, and when the solution cools, it crystallizes in silvery scales, lighter and more brilliant than the elaidic acid itself. This salt dissolves readily in hot water, and when cautiously cooled, crystallizes in needles. Eiaidates of potash and ammonia may be obtained in the same wav. The former of these crvstallizes in light brilliant needles. They are both soluble in alcohol and in water, especially when hot. The insoluble eiaidates are easily formed by double decomposi- tion. Elaidate of magneaia. is not sensibly soluble in water. It is very soluble -n alcohol of 0-817. ale J Ace H I)ass( cong ream wash] folds Tl, into e Bui tainty, Lesca nitrate not coi Rou olive oi than th ment fc pile, cc which _ poles is metallic netic, ai Jts point thread t in comm needle 'n which it which th tlie other Now, if where in deviation «il is, the demonstr any other of olive oi When .s, of animal 1 "Jive oil. OLIVE OIL. 437 lis of iOSSCS tcil in 0-837 vege- cposed I small ^. Its of am- ortion ; specific )ecome9 )(la lev. le alljali, n water, t masima sisted by as a fluid has been [leated to ved in bot Y brilliant x)lves it in ivoportions f alcobol, on ;') parts Iboiling, is Lvitbout al- js'ovted into |es tbc ear- Inly to beat Iporate tbe r of 0-817. In cools, it It than tbe [water, and tbe same ^nt needles. wben bot. [decomposi- It is very ElaUlate of lead is insoluble in water; but rather more soluble in alcohol than elaidate of magnesia. Elaidate of mercury is slightly soluble in ether. M. Boudet analyiced elaidate of silver, and found it composed of Elaidic acid . . 70-125 or 34-06 Oxide of silver . 2<)-875 or 14-5 100 According to this determination, the atomic weight is 34-06. When elaidin is distilled it yields abundance of gas, and a liquid passes over, amounting to about half the elaidin, which gradually congeals. It contains water, acetic acid, a volatile oil, an empy- reumatic oil, and a good deal of elaidic acid ; easily obtained by washing the product in water, and subjecting it to pressure between folds of blotting paper. The oils of almonds, of filberts, and of acajou, are also converted into elaidin by hyponitrous acid.* But this test of the purity of olive oil has lost much of its cer- tainty, since it has been shown by Bourdet that castor oil, and by Lescalier that poppy and almond oils, coagulate like olive oil, with nitrate of mercury. Linseed oil and nut oil, on the contrary, are not coagulated by that salt. Rousseau has proposed another method for testing the purity of olive oil, founded on its being a much worse conductor of electricity than the other vegetable oils. He has contrived a particular instru- ment for testing olive oil in this way. It consists of a dry galvanic pile, composed of very thin plates of zinc and copper, between which are placed pieces of paper steeped in poppy oil. One of its poles is placed in contact with the earth ; the other, by means of a metallic conductor, is placed in contact with a needle feebly mag- netic, and very freely suspended. The needle has a small disc at its point. Another disc of the same size is fixed by a metallic thread to the support of the needle. The pole of the pile is brought in communication with this last disc. To use the instrument, the needle is so placed, that in consequence of its polarity, the disc which it carries abuts against the immoveable disc. The electricity which this last disc receives from the pile, is communicated also to the other disc. The consequence is, that tbe needle disc is repelled. Now, if a layer of oil, of a determined thickness, be placed any where in the electrical circuit, we can see how much it causes the deviation of the needle to diminish. The wo.'se a conductor the oil is, the slower is the deviation in taking place. Rousseau has demonstrated that olive oil co iducts electricity 675 times worse than any other vegetable oil. 3 cirops of poppy oil added to 177 grains of olive oil, quadruples the conductibility of this last oil. When such a test is used, we ought to remember that the stearin of animal fat has nearly the same degree of non-condiictibility with olive oil. » Anil, lie Cl.iiii ct do I'livs. 1. aoi. hui -i t: i'l.i H I I Jil 438 IIXEU OILS. Olive oil remains longer than any other vegetable oil without becoming viscid. On this account watchmakers employ it, after having purified it in the following manner : — The oil is put into a crystal bottle along with a plate of lead, and after being corked, it is placed in a window, where it may be exposed to the direct rays of the sun. By little and little, a cheesy matter separates from the oil, and partly swims on its surface, and partly falls to the bottom. The oil loses its colour, and becomes limpid. When the separation of this cheesy matter is at an end, the oil is decanted off, and kept for use. It appears from the experiments of Fremy, that when olive oil is mixed with half its weight of concentrated sulphuric acid, taking care to prevent all increase of temperature, and the mixture left for 24 hours, there are formed sulpho-margaric acid, sulpho-glyceric acid, and sulpho-oleic acid.* SECTION II OF OIL OF ALMONDS. This oil is obtained by expression from the fruit of the amygdalus commtmis. It has a light yellow colour, is very fluid, has an agree- able taste, but no smell. Its specific gravity at (iO^ is about 0*918. When cooled down to 14°, it gives, according to the experiments of Braconnot, 24 per cent, of its weight of stearin, and 76 of elain. The stearin melts at 43° ; but the elain does not congeal at the lowest temperature to which it has been exposed. But this state- ment does not agree with the results obtained by Schubler and Gasserow. According to the last chemist, almond oil contains no stearin at all. Saussure left oil of sweet almonds for four years in contact with oxygen gas over mcrcui'y. The oil absorbed IH'G times its bulk of the gas, giving out at the same time carbonic acid and liydrogen. The residual gas was 0'33'";5, or very nearly ^d of the whole, and was composed of Carbonic acid .... 96 Hvdrogen . ... . 20*4 Azotic ..... 18"7 6-9 Oxvjjen 142-Ot SECTION III. -OF ItAJ'ESEEI) OIL. This oil is obtained by expression from the seeds of hrassica rapa and napus. It is yellow, and I'as a peculiar smell. At the temperature of 28°, it congeals into a yellow mass, and, according to Braconnot, contains 46 parts of stearin, and 54 of elain. The stearin melts at 45°{r. The specific gravity of the oil from brassica napus is 0*9128, at 59°, and that i'vom bnissica ropa, 0*9167. When cooled down to 43°, both of these oils deposit white globules of stearin, and when cooled down a few degrees lower, they assume the consis^tcnce of butter. ' Ann. de Cliiin. ct ilc Tlixs. Ixv. 117. f Ibid. xlix. 228. aisc oli befor for colon It alcol) wliilt thick diate It Til by b(i LAUREL OIL. 439 itliout after into a ved, it !t rays )m the ottom. iration id kept e oil is taking left for glyceric mjgdalus n agree- itO-918. ments ot of elain. il at the [lis state- iblcr and ntalns no itact witli s its bulk ivdrogen. liole, and Of these plants, the seeds of the brassica rapa yield by far the most oil. assica rapa emperature Braconnot, .'in melts at sis 0-9 128, led down to whcncooletl of butter. xlix. 2-28. SECTION IV. — OF OIL OF COLZA. This name is given in France to a superior kind of rapeseed oil, extracted from the seeds of a variety of the hrassica campestris. It is used in lamps, and lias a specific gravity of 0*9136 at 59°. The seeds give 39 per cent, of their weight of oil. SECTION V. — OF OIL OF MUSTARD. This oil is expressed from the seeds of the sinapis olha and nigra. Those of the white mustard give about 36 per cent., and those of the black about 18 per cent, of their weight of oil. It has an and)er colour, is destitute of smell, and is thicker than olive oil. The specific gravity of the oil from the black mustard is 0*9170, and that from white mustard 0*9142 at 59°. It dissolves in 4 times its weight of ether, and in 1000 times its weight of alcohol, of 0*833. It makes an excellent soap, and is beginning to be used instead of rapeseed oil. SECTION VI OF TEA OIL. This oil is much used in China, both for lamps, and as an article of food. It is expressed from the seeds of the Camellia oleifera or sesangita, and perhaps from other species of that genus of plants. There is no evidence, notwithstanding its name, that it is ever ob- tained from the seeds of thca ; though it is probable that these seeds also yield an oil. It was examined in my laboratory by Dr R. D, Thomson. The colour of tea oil is a pale yellow, and it is nearly as liquid as olive oil. Its specific gravity is 0*927. It has no sonsible smell when pure. It remains fiuid at 40°, but at 39° it acquires the con- sistence of an emulsion. Its temperature may be raised above 660° before it begins to boil, or at least while decomposing. When kept for some time at that temperature it becomes thick, and dark coloured. It burns with a remarkably clear white flame. It is slightly soluble in sulphuric ether, but insoluble in water and alcohol. Neither nitric nor nitrosulphuric acid act violently on it while cold ; but nitric acid, assisted by heat, converts it into a thick yellow fluid, having a peculiar smell. Sulphuric acid imme- diately blackens it. It consists of about Stearin Elain 75 100 SECTION VII. — OF LAUREL OIL. The oil from the berries of the layrtis nobilis cannot be obtained by boiling the bruised berries in water, as has been shown by M. v\ \ .): i 440 FIXED OILS. H ! Menigault ;* but it may from the recent berries by pressure. It exists only in the parenchyma, or bhick j)ulp which surrounds tlie cotyledons. M. Subeiran bruised the dry berries, then exposed them to the vapour of Wiiter till thoroughly soaked. In this state, subjected rapidly to the press, they yielded laurel oil.f SECTION VIII OF OIL OF ALVSSUM OR MYACMIUM SATIVUM. This oil is obtained by expression from the seeds of the alyssum sativum, a cruciform plant, occasionally observed in England, though liardly a native. When freed from mucilage it is light-yellow and transparent. Its smell is similar to that of the seeds from which it has been express- ed. Its taste also is disagreeable, leaving an aromatic impression in the mouth. It remains licjuid though cooled down to 21"; but it congeals when exposed to an intense cold. It is not a drying oil, and would not answer for painters. IJut it is excellent for burning in lamps, giving a clear and strong light. It r'ombines with the caustic alkalies, and forms soaps ; but they never actjuirc the consistence of hard soap.J I. I if rt I i ^ ii DIVISION IlI.—OF SOLID OILS. '1 !»ese oils are obtained from j)lants in a solid state. Some of them have some resemblance to tallow ; but the greater number ap- proach nearer to wax. SECTION I. — nUTTER OF CACAO. This oil is extracted from the seeds of the theuhroma cacao, either by expression in a high tem])crature, or by boiling in water. Butter of cacao is yellowish ; but it may be rentlered almost colourless by agitating it, while in a state of fusion, in hot water. It has the same smell as the * Plianiiiicie. xxi. .j-iO. f ll)iil. p. 521. X Henry, Jour, de Pliariimci;, yvi. 71- i| Jour, do I'liiiriiiacii', xx. ;j.JL». Joui. ill' IMiaruKicio, .\x. 'V.Vl. gii oil into a smell "greeaL punity. ties of It is I'revent, s«ife uio siibstaiK i^ciii, but Ohtii tile myfi, land, fro: ^iit cakes ^at butyn * I) BUTIVER OF NUTMEG. It tlie ised tate, I. issuni ougli t. Its essiou ' ; but Hut it ;ht. It ^r never Some of ubev ap- 10, eitlier Butter urless by bas tbe the cou- at 122°. (niietiuics lare lil^ely nearer to [reatcd by Ituting h1- acted on \utyracea; ; lio-c-y .'How It bas an . 52 1. 441 It ll-lf, XX. -J :y.i\). agreeable smell, which has been compared to thtit of violets melts when heated to 91)° l. it is sjiid to be composed of Stearin 31 Elain G9 100 It becomes readily rancid, and whitens at the same time. It is slightly soluble in alcohol, to which it gives a yellow colour. Its solution in ether is orange. In this country it is used in considera- ble quantity, in thr- manufacture of yellow soap, to which it connnu- nicates a fine (Colour, and a degree of softness which makes it more agreeable to washerwomen. It is said to come chiefly from Africa. M. Frederick Mi(;baelis found that this oil may be de})rived of its colour in the following way : — The oil was melted in a copper vessel, and about j^th of its weight of black oxide of manganese in fine powder was put into it, and the whole well mixed together for 8 or 10 minutes. Then a (quantity of boiling water, ecjual to half the weight of the oil, was added, and when the liquid was boiling a quantity of concentrated suli)huric acid was added, amounting to about ogotb i)art of the weight of the oil. The whole was now well stirred, and left to cool. The oil collected on the surface of the water, while the manganese fell to the bottom. The colour of the oil became yellowish-green, and when exposed for some days to the action of the air and light, it became as white as hog's lard.* SECTION IIK — OF TOULOUCOUNA OIL. This oil is obtained from the fruit of a tree which grows in Sene- gal, and which has been described by M. Perrottet under the name of carapa tonloucoima. The seeds are drupas, about the size of a nuisket bullet. When bruised, and thrown into boiling water, the oil separates and swims on the surface. It concretes, on cooling, into a butyraceous substance, having a yellowish-red colour. Its smell is rancid, and its taste exceedingly bitter and hot, very dis- agreeable, and exciting vomiting. Yet hogs eat the fruit with im- punity. It melts at about 110°. With reagents, it has the proper- ties of a fixed oil. It is used by tbe natives to anoint their skins, which eftcctually prevents the ])unctures of insects. It bas been recommended as a safe medicine for destroying vermin in the heads of children. The substance which occasions the bitter taste has been supposed an al- kali, but has not been examined.! SECTION IV. OF BUTTER OF NUTMEG. Obtained by exjjression from the nutmeg, which is the fruit of the myrislica aromatica, or moschata. It is manufactured in Hol- land, from which country it is exported in tbe form of four-sided flat cakes. It consists of two colourless oils similar to tallow : of a fat butyraceous yellow oil, and of a volatile odoriferous oil. * Pdi^ijcndorrs Aiiiiuk'ii, xxviu 6y'i. f X'iroy, .luur. dc Pharuiiiuii', xx. 307. )[ i l| 1!' I' It 442 FIXED Oils. Mr- ,: t r~«*fi I According to Schratler, Hi parts of butter of nutmeg are com- posed of Tallow-like oil .... 7 Yellow oil . . . .8^ Volatile oil .... i 16 It is decomposed by cold alcohol and ether, which dissolve the yel- low and volatile oils, and leave the tallow, which still retains the odour of nutmeg. To separate the volatile oil from the yellow oil, which remains after the evaporation of the alcohol, it is mixed with water, and the volatile distilled off along with the water. When butter of nutmeg is boiled with 4 times its weight of alco- hol or ether, it is completely dissolved ; and during the cooling the tallow precipitates. Tliis butter is employed on the continent in medicine, and always externally. I am not aware of its being em- ployed in this country. Lecanu has observed that this butter has a greater resemblance to Hip animal solid oils than to the vegetable.* it is often imitated by boiling animal fsit with powdered nutmeg, and colouring with safflower. But this fraud is easily discovered ; for ir'.ich a mixture will not dissolve in 4 times its weight of boiling tiicoiial. That portion of the fruit of the myristica moschata called tnacc, contains a volatile oil and 2 Jixed oils. One of these may be ex- tract" 1 by alcohol. On evaporating the alcohol, a red coloured oil 1 jTficiii.s. The other oil is insoluble in alcohol ; but it may be ex- tracted by ether, or obtained by expression. It is yellow. The properties of these oils have been investigated by Bollaert. SECTION V OF COCOA-NUT OIL. This oil is obtained by expression from the kernel of the cocoa- nut, the well known fruit of the cocas niicifera. It is white, and of a pretty hard consistence. Yet it contains both elain and stearin. Of late years it has begun to be employed in considerable quantity in this country as a substitute for tallow in soap-inakiiig. It is r.ot easily saponltied. The soap made from it in India is rather a mix- ture of cocoa-nut oil and carbonate of soda. But I have been assured by more than one of the most skilful soap-makers in this country, that they have succeeded in converting it into an excellent soap. The stearin of this oil is used also as a substitute for wax, in the manufacture of candles, for which, on account of the high temperature requisite to fuse it, it answers very well. SECTION VI. -OF llUTTEIl OF IFLIPE. rli 'I ." This solid oil is extracted from the seeds of the hassia latifolia, a tree which grows abundantly in Bengal, and on the Coromandel coast. The oil is probably obtained by boiling the seeds in vvator. * Jour, rie Pliarriiacic, xx. ;Jo9. Iti cole tasti It r Wh( is sc liqui cools lent obtni Wt the Wi in so drawn Bee wax fr had be their v the po food of sugar, and is ( Wax peculi.ii the vva> melted the ligh they an required Wax, The sp( 0-9C50§ ii- is . Jit-Tt und When pemture into a ( I'esumes the heat and if a , Hith a hv ^or makii i Bostock, ] BKKS WAX. 443 3om- c yel- ls the )W oil, d with f alco- ing the aent iti ing em- inhhincc nutmeg, ["Dvered ; f hoiling led mocf', ay be ex- ioured oil av be ex- ,w. The Ihe cocoa- [te, and of Id stearin. le quantity It is v.ot licr a mix- have been n-s in this t excellent for wax, the high [a latifoHa, poromandel Is in water. It is solid at the temperature of 73°. It has a light greenish -yellow colour, and an aromatic odour resembling that of olive oil. Its taste is at first sweet, but it leaves an acrid impression in the mouth. It melts at about 82°, and when liquid, has a fine yellow colour. When filtered, it leaves a little brown matter containing tannin. It is scarcely soluble in alcohol of 0-842. Ihit wlien boiled with that liquid, a little stearin is dissolved, which crystallizes when the liquid cools. It combines readily with the alkalies, and nmkes an excel- lent soup. From the soap, abundance of stearic acid may be obtained.* SKCTION VII. OF bees' WAX. Wax differs from the solid vegetable oils in its consistence and in the way in which it combhies with alkalies ; but it resembles them in so many respects, that an accurate line of separation cannot be drawn. Bees' wax, though an aiimal production, agrees so closely with wax from plants, that it would be improper to separate them. It had been the received opirion of nattiralists, that the bees collected their wax from the pollen of plants. But Huber has shown that the pollen which the bees carry to their hives, is employed as the food of their larvtc ; and that the wax is manufactured by them from sugar. It exudes from the rings in the abdomen of these insects, and is employed by them in constructing the walls of their cellst. Wax, as it comes from the bee-hive has a yellow colour, and a peculi;iv smell, both of which are derived from the honey, with which the wax cells are filled. To free it from these impurities, it is melted in water, and cast in:o thin ribbons which are exposed to the light of the sun, till by the joint action of the light and moisture they are bleached white. Several fusions and exposures are usually required to render it quite white. Wax, when pure, is snow-white, and without taste and smell. The specific gravity of unbleached wax varies from 0"9600| to 0-9G50§ ; that of white wax from 0-8203 to 0-9()02.§ ii, is insoluble in water ; nor arc its properties altered though kept under that liquid. When heat is applied to wax, it becomes soft; and at the tem- perature of 142° if unbleached, or of 15.5° if bleached, ||. it melts into a colourless trans})arcnt fluid, which concretes again, and resumes its former appearance as the temperature diminishes. If the boat be still further increased, the wax boils and evaporates ; and if a red heat be applied to the vapour, it takes fire and burns with a bright flame. It is this property which I'enders wax so useful for makin}!: candles. * O. Henry, Jour, de Pharmacie, xxi. 503. t Tliis was first ascertained by Mr Joliii Hunter. \. Bostock, Nicholson's Jour. iv. 1;JU. \> Fabroni, Crell's Annals, 1797, ii. i'2o, |l Bostock, Nicholson's Jour. i. 71. '\ i •> i! '. 1 Ji ;.l m 'ii ,'i' ' !: r" t ll I 444 FIXED OILS. '!::'] ^ Wax is s-vfarcoly acted on by alcolu)! vvlion cold, hut holliii'' ami swims upon tlu- suil'ace of \\at( r. When coliol ;(l 1)) renter wn by isisted ts tlio n, wlio Tlicy I takes soluble oreasy- soUibU; lis i'()*»l- Unites jeordinj? the wax times its Id ether. , distiUiMl iric acid oic aci Mf/ririn, wlien distilled, passcvs over almost unaltered. It melts wlien beated to tlie teiaperatiire of I4!)'\ It reijuires to dissolve it, 200 times its \vei«j;lit of boilini>: alcohol of O-H'.V,), and 123 times its weijjht of anhydrous ahrohol ; but at tlie ordinary temperature; of the atujosphere it is insoluble in both TKiuids. When the solution cools the myricin is deposited in flocks. It dissolves in 9!) times its weight of cold ether, and is still more soluble in that liquid when hot. It is v( 1 atom ox)v:«'n . = I . H2-I!> . i2-:{:i r)-4K ;}!> lH-2r) lOO-OO Acconlinuf to this siipjiosltion, wax is a coiiiixhiiuI of 3!) atoms, ami the wt'ii^ht of an iiitc^jfni purticlo of it is IH-ya. l''roin tlio oxpcrimcuts of ( lOvriMil on >u,i|)>i, thoro is some reason for l»elio^ iui; tliut tlie weiffht of an atom of wax is nearly ih)nl)hi the nam' it hero assigned, or HG. If this nnmher were iiccnrate, its true con- stituents wouhl ho, 40 atoms earhon . . = .'50 32 atoms hyiln)<>:cn . . =4 2 atoms oxy^MMJ . . =2 3(i The analysis of Oppermann, by moans of oxide of eo])pcr, does not deviate very far from that of Lavoisier. He ohtained Carbon 80'IH or 37 atoms = 27'7') or per cent. NO' 14 Ilydrojuen 14*07 or 3!) atoms = 4'S75 — — 14-08 ()xy«,'en 5- 7") or 2 atoms = 2*00 — — ,'>-78 100-00* 34-()2r) 100-00 Aceordini; to Ettlinjz's analysi,^, cerin, niyriein, and eorain, are isomerie bodies, and eomi)osed of CJ''^ II''' (). liut as wax is a mixture of three dillbrent substances, it is obxious that no valuable inference can be drawn from these experiments, till they be repeated on each constituent of the wax. SECTION Vi;!. OF MYRTLE WAX. The myrtle wax o; [Korti. America is obtained from the myrka cerifera. Wo are i''.l»Lt(H5. to I)r Hostockf and Mr C'a(let,t for a very exact account of its jiroportios and extraction, '.riio myriru cerifera is a shrub which grows abundantly in Louisiana and otlu-r parts of North America. It produces a berry about the size of a jjoppcr corn. A very fertile shrub yields nearly seven pounds. The berries are picked otf, thrown into a kettle, and covered with water to the depth of about half a foot. The kettle is then boiled, and the berries stirred and squeezed against the sides of the vessel. The wax which they contain is melted out and swims on the surface. It is skinnned oti", passed through a doth, dried, molted again, and cast into cakes. From the observations of Cadet, we learn that the wax forms the outer covering of the berries. The wax thus obtained is of a pale green colour. Its specitic gravity is I'D 150. It melts at the temperature of 100° : when strongly heated it burns with a white flame, produces little smoke, and during the combus- • Ann. dp Chiin. et de Plus. xlix. 244. f Nicholson's ,Iuur. iv. IW. ' } Ann. do Cliim. xliv. 160, JAPAN WAX. 447 t.(»ms, in tho ami t'J' •r, iloi's •14 •08 rlH )^00 •iiin, arc < obvious i-inients, myricn i,X tor '^ myricn lul otluT si/c of ii pounds. 3re(l with !n boiled, 10 vessel, surface. rain, and 11 that the ax thus Is 1-0150. ,1 it burns p coinbus- ». I GO. tlon (MuitH an afjrtM>.il)l(> nroniatic odnur. Wafer does not art upon it. Alcohol, wlicn hot, dijtsolves ,_,\,M» of its wciijilit, but h.'tH most of it f.ni a^rjiin oil cooliii/r. I lot t'tlicr dissolves about |th of itrt weiui'it; and, when slowly cooKnl, doposltH it in crystalline plates, like i-i .rmaccti. 'i'lie other accpiires a y;recu colour, but the wax b 'coincs nearly wliito. Oil of turpentine, wlien as&isti'd by heat, (iis8olv(-s it sparinju'ly. Alkalies net upon it nearly as on boos' wax. 'I'lie 8anie remark applies to acids. Sulphuric aeid, when assisted by h(>at, dissolve's about ,',, th of its wri^lit, and is iron verted into u thick dark-browM mass.* Mr llatchett has diitected a substauce ])reeisely similar to invrtlo wax in /«r.t It probably exiats in many vejretables. 'I'lio wax from tlu> luyrica cordifolia, a shrub wliieh j,m'()ws at tho (^ipo of CJood ll()|)e, has biuMi «>xamined by i)r .lolin, and f" )m the characters which he assiifiis to it, we may consider it as ' "arly the saim; with the mvrtle wax of North America. t siu-rioN IX — or itiiA/ti, wax. Mr Hrande, in 1H||, pii1)lislied a chemical examiiiatit ui w,ix from Urazil, the produce; of an unknown tree in that country. § It had a ifrcenish colour, was insoluble in water, but stdnble in alcohol, other, and oils. Its specilic jj^ravity was 0*<)80. It melted at the temperature of 200°. It could not he made to form a soap with tho fixed alkalies; but answered remarkably well for candles. || Brazil wax was analyzed by Oppermaiin, who obtained Carbon 7l"HK or atoms = 4^r> or per cent. 72 Ilydrojron 12*0;$ or atoms = ()^7;> — — 12 Oxyjrcn 1 ()•(>!) or 1 atom — I — — 1(5 100-00^[ ()-2.'i 100 We see at least, from this analysis, that the constitution of Brazil wax is very different from that of bees' wax. SECTION X. OV .TAl'AN WAX. A species of wax has been known for some time in India, under tlu! name of Japan wax. A specimen of it was sent nu about three years ago from Canton, liut no information was communicated respecting the plant from which it wa? procured. Its colour is white, with a slight shade of yellow. It is translu- cent when in thin slices, and is softer than bees' wax. Its specific gravity is 0'()7. It melts when heated to 104°, and becomes solid again when cooled down to 93°. It does not stain ])aper. It is soluble in alcohol and ether when assisted by heat ; but on cooling * Bostock, Nicholson's Jour. iv. l.'JO. f Analytical Experiments on Lac, I'liil. Trans. 1804. % Cliimische Uiitorsuclmnjren, iii. S8. § It uppcars from the observations of M. Vircv (Jonr do Pharmacio, xx. 112), that tho tree yieltliiig this wax, called carnanhn in Brazil, is the curypha ccriftra of M. Arriida. II Nicholsoirs Jonr. xxxi. 14. S Ann. de Chiin. ct dc V\\ys. xlix. 242. IMAGE EVALUATION TEST TARGET (MT-3) Kt ^ ^•^ i f/. 9 1.0 ^1^ I 11.25 2.5 2.2 I.I f "^ 1^ 6" U 1 1.6 '^l ^/ 0\ Hiotographic Sciences Corporation 23 WEST MAIN STREET WEBSTER, N.Y. MSSO (716) 873-4503 i\ :<\^ \ :\ 4^\ ^ ^ \ ^ 4^ 4^^ ^ "^'^ %^ i^ A V * 448 FIXED OILS. it is deposited from the latter in flocks, wliile the alcoholic solution, on conlinj!^, becomes thick and opaque. This wax may be combined with soda, and converted into a soap. By this process the wax is converted into a solid acid, not resembling stearic acid, and doubt- less peculiar. From Oppermann's description of an East India wax which he examined, it is obvious that it is the same with the Japan wax. He found it composed of Carbon 70-00 or 53 atoms = 39*75 or per cent. 70-09 Hydrogen 12-07 or 55 atoms = 6-875 — — 12-14 Oxygen 17-93 or 10 atoms = 10-00 _ — 17*77 100-00* 56-625 100-00 A constitution very different from both that of bees' wax and Brazil wax. But it is obvious from the properties of Japan wax, that it contains, at least, two distinct principles, which would require to be examined separately before any useful conclusions could be drawn. SECTION XI. OF FOSSIL WAX OF MOLDAVIA. Found in Moldavia in masses of considerable size, and presented by Dr Meyer to the Scientific Association at Breslau. Colour, dark-brown. Composed of two substances, one soluble in alcohol, the other not soluble in oil of turpentine. Magnus ana- lyzed it, and obtained Carbon 84*6 or 100 atoms = 75 or per cent. 84-69 Hydrogen 15-3 or 108^ atoms = 13-5625 — — 15-31 99-9t 88-5625 100*00 SECTION XII. — COW-TREE WAX, OR GALACTIN. This substance to which I have given the name oi galacthi, exists in the milk of the cow-tree, or Galacfodendron utile of Humboldt, iliito : llint with titu i«>niim* Hult \h Hcniity, witi) till* litttiM' ulttiiitlaiit. Tlio uK'oliolic Htilutiou ix y«'ll»»w luul v»M*y hitter tiiHttid. VViitor (UH'tiHioiM n |U'(U'i|iitiiti', which in rotliriHiilvtul on u^ittitiiig thu rHjiiiil. This Hohitioii is pivcipittittHl hy nitnitt* itt' inut, iiitriiti^ of miM'ciiry, Hiilphato ut' /inc, siilpiiato of inan^^aiu'sr, (rhhiriiio of hariiiiii, r.hhi- rido of stroiitiiiiii, ('hh)ri(h> of 4'ah'iiiiii, aiul uiuriato of nui^iicHia. Whoii gahu'tin is |)ut into coiitu'iitrattul Niil|>hiii'i(^ arid tlio liiiuid ussiiiuos a \\\\v hi'ownish~nMl co'.otii-, wliirh ^nuhiallv di>(>|i«ai's ^rooii hy I'cthn-lcd li^ht, and iU'i'\} ImiwuiHh-i'ud l»y transuuttod li<{lit. 'i'ho i^ahictiii hciroiiu's Hoft and dai'k-lirowii. WhtMi heat is applied, olh>i'V(>s(>(Mir(< talu^s phico, tho ^ahuMiii ix fhan't'd, and sulphnrons acid disonj;'a««('d. \VI\cu j»ahii'tin is h»'atod in water it does not Ihiat on the surfaee of that Tapiid unih'i* the form of a transparent oil, as is thit <;ase with wax nnch'i* the SHn\e * irenuistaiiees ; hnt it ind>ii>es a j^reat «h'al <»f water, and assmnes tiie form i>f a wliiti>, «ipa(pie, viseid matter, not uidike the i;hiten of wheat in its appearaiu'e and adhesiviMu^ss, hut innel) more thiid. 'I'he transpartMit liipiid matter which remains wIkmi the cohl idco- holic sohition fnnu the cow-tree milk is distilled oil' in a retort, possesses most of the i'haracters of pdactin, if wi' except the li(ptid form nn(h>r which it appears. It is eiptally fixed, and e(pially eom- hustihh>. It is destitute (»f tast(^ and smell, stains paper like an oil, and does not comhine with potash, hnt dissolves in nitric^ und Htd- phuric acids with the same phenomena as ^alaetin. The two most strikinu^ cir»'ntnstances in which it diU'ers from ^alactin, an^ its Mohd)ility in cold alcohol, and its li(piidity. It does not lose its transparency, hnt concretes into a kind of varnish like the drying oils. SKCTION xiii.- oi- u.'.y '" t;EH()XYL()N ANH1(!<»I,0. hi The tree which yiehls this ' vaa tirst descrihed and named hy M. llumluddt. It orows on tiie Andes at t^nindiu, in South America, and occupies a zone on these mountains, from the heijj^ht of 7530 to 1)S4IJ ft et aht)ve the level of the sea. The mean tem- perature of this i< -.ne varies from 5*2*' to (i4'^f,, aceordinjj^ to its height. The tree ■•ises to the height of ahout H>4 feet, ami its trunk is ahout 2 feet in dianieter. It is, therefore, one of the most majestic palms of the intertropical regions »)f South America. The \va\ of this tree is scraped, or rasj)ed olf the hark. When the raspings are heatetl in water, the wax separates from the im- purities with which it was mixed, and swims on the surface of the water without melting. It is made up into halls, and dried hy ex- posure to the sun. When melted it has a deep yellow colour, slightly translucent, and possesses a good deal of the frangihility of resin. It melts at a temperature a little higher than that of hoiling water. When nd)hed it hecomes strongly electric. It hums w itli tlanie, and gives In tl i'nportf he an ail. ' oils onl WAX (II CICIIOXVI.ON ANIIK Ol.tl. V)l out a ^n^at iloal ()(' Hiii(ik(>. Mot alcohol d'lHKolvi'H it roadily. On cooling tlio rK|uiil (UituTot(>H into a ^rclatitioiis miohh. Ktlioi* diit- Holvt^rt it. My rautioiiH ('vaporatioii it may Ixi olitainitd in tlio Htato (d* Hilky I'ltatmM'ri. (JaiiHtic alkalios attack it with diiiicnity, lint p;radnally diHsolvo it. M. ItouHHin^iinlt cxaniiiicd it, and rmind that it (lonmHtitdof a wax, poHSOriHinii; i^xai^tly the clniractiM'M iind couHtitntion of hcA'M wax, aiitl of a |inr(W<'jv<;/. 'riu^NO two HidistanccH li«riiii^' nn(!<|nally Holnhio in alcohdl, may ho HO|iarat(!d in tlur followin;.^ maniKM' : — l)i;4i>Ht tho wiix of tho ti'co in a coiiHidtM'ulih^ cxc.ohk of lioirniHin, from which it may lio frtMMl, liy diHrtolvin<^ it two or thrc(t tiincH HnccrHHivoly in lioilin;^ al(Mihol, and allowin>^ it to fall down wluni th(> Holntion'coolH. 'I'lu^ cold altMihol rotains the n^Hin in Holntion, lint not ((iiito frc(; from WIIX. Distil oil' one-third of the alcohol, and lot tin; H rosin is ditpositcd, mixed with a little wax. (''ontinne tho evaporation till only omvtonrth of thtt rnpiid rcMiiains : the resin falU ilown, havin<:f ii crystalline! aspi'ct and a (iiu! white cohmr. 'I'hen! nMiiains in tint ahMihol a liittcr-tnsttMl Kulistani^s whiidi HouMsin^anlt (ronsiders as a nalt of an unknown ve;>;(;tahle nlkaloid. 'IMiu wax hinutf analyzed liy M. Honssin/^ault, he ohtained Oarlion H0-2H IIydro},'eii .... i:{-2() Oxy<,'en .... O-.Oii oils. ;i Sovitl \»e\}iht an teui- H> its anil its tlic nuist •a. When t,l\e im- ^.e of the ;d by ex- naluccnt, It melts When iviul gives 10()-()0 This aiiprrmin(!d liy the analysis (if Oppermaim, H'iv(>n in a pr(!C(!dinj^ Section, that th(M'o can he no donht that the cdnHtitution of lioth is prec^isely tho same. The resin reepjin^s to melt it a tiMiineratiire hi<>;lier than that of hoiliii*; waU^r. When nudtel it looks like andior. On con- eretinir it splits in all dinuitions. It is nnieh more solidde in hot than in cohl ahrohol. It is soluble also in etluir, and in the volatile oils. It was analyz(ul by M. Houssin^'ault, and found composed of C'arbon H2'l!» or .'Jr* atoms = '2()-*2.') or per cent. 82-3.^ Ilydrojren ll-.W or '2!) atoms = :j-(i2r> — — ll-:n Oxyj?en ()-28 or 2 atoms = 2-<)() — — ^'e2H 100-00* .31-875 100-00 In the preceding Sections an account has been given of the most important of the iixed oils, whether dryin ' * I have cxamincil the acid formed during the distillation of oil of turpentine. and found it acetic acid. Its properties are disguised by some reain which it holds in solution. But I saturated it with soda, and fused and filtered the salt of soda formed. It then possessed the well-known characters of acetate of soda, and when distilled with sul|)huric ai;id, gives pure acetic acid. t Ann. de Cliini. et dc Phvs. lii. 40.5. m M 464 VOLATILE OILS. 1 volume carbon vapour weighs I volume hydrogen gas . 0-4133 0-0694 0-4827 and -4827 X 10 = 4-827. It ought to follow from this that pure oil of turpentine of the boiling point 313°, when all foreign matter is removed, is a compound of 10 volumes carbon vapour 10 volumes hydrogen gas united together and condensed into 1 volume. Or it ought to be a decacarbohydrogen . Saussure found that oil of turpentine, left for three years and nine months in contact of oxygen gas over mercury, absorbed 127^ times its bulk of that of gas. 118 tines its bulk of the gas were absorbed during the first year, and only 9^ times its bulk during the last two years and nine months. The residual gas was 0-78, or more than ^ths of the whole oxygen gas absorbed, and con- sisted of Carbonic acid . . . . (56 Hydrogen . . . 20-5 Azote ..... 13-8 Oxygen ..... 0-3 100-6'' M. Boissenot observed, that when it thus absorbs oxygen, it de- posits (when cooled down to 20°) white crystals, the properties of which he examined.f It has been long known t'lat when oil of turpentine is placed in contact with chlorine gas it catches fire, burning with a dark-red flame, and giving out a great quantity of smoke and soot. This happens when a feather, dipt in oil of turpentine, is plunged into a phial filled with chlorine gas. When a small quantity of chlorine is placed in contact with a large quantity of oil of turpentine it is ab- sorbed, the oil becomes yellow, and acquires consistence. Iodine is dissolved in great quantity in oil of turpentine. The solution, when saturated with iodine is yellowish-brown. Neither metallic silver nor starch detect the presence of iodine when dis- solved in oil of turpentine. But when nitrate of silver or calomel is agitated with the solution, iodide of silver or of mercury is formed. When the solution of iodine in oil of turpentine is distilled, pure oil of turpentine first comes over, and then a brown oil saturated with iodine. Oil of turpentine absorbs a great quantity of muriatic acid, and forms a crystallized substance, having considerable resemblance to camphor, and, therefore, called artificial camphor. It was dis- covered by M. Kind, apothecary in Eutin, while employed in making ' Ann. de Chitn. et de Phys. xlix. 23.5. f .Tom. de Pharmacip, xii. '214. were mi added, was the tTro 459. i Am OIL OF TUnPENTlNE. 405 pure attev be a '9 and 127^ were luring 1 0-78, 1 con- n, it tle- erties of laced in Lark-red This fd into a ilorine is it is ab- le. The Neither Irhen dis- calomel formed. I, pure oil ted with lacid, and Dlance to was dis- In making a medicine called liquor orthrilicus Pottii,* about the year 1803. He put a quantity of oil of turpentine into a Woulfe's bottle, and caused a current of muriatic acid }?as, expelled from common salt by sulphuric acid, to pass through it. The oil became yellow, then brown, and at last almost solid, from the formation of a great num- ber of crystals in it.f This experiment was repeated by Tromms- dorf. He examined the crystals, and found many of their proper- ties similar to those of camphor, though others were different. The Society of Apothecaries in Paris, on being informed of these par- ticulars, appointed Cluzcl, Chomet, and lioullay to examine the subject. The result of their labours was published by Boullay.J They determined the weight of the crystals yielded by oil of tur- pentine, and the dose of muriatic acid requisite. They ascertained the properties of the crystals, and endeavoured to explain the way in which they were formed. The experiment of Kind was repeated by Hagen, in 1804, § and by Gehlen, Schuster, and Pesth, in 1805, chiefly with a view of elucidating the theory of the process. || They were also repeated by Thenard with the same object.^ According to Saussure, 1 volume of oil of turpentine absorbs 163 volumes of muriatic acid gas. The oil ought to be surrounded with ice, otherwise it becomes hot, and allows the gas to escape. When the process is finished, the whole is left at rest for 24 hours. The quantity of crystals formed varies according to the oil of tur- pentine employed. Oppermann could obtain only crystals corres- ponding to 30 per cent, of the oil employed;** Trommsdorf obtained 26 per cent, of the oil in the state of artificial camphor ; Cluzel obtained 47 per cent. ; and Thenard 1 1 per cent.,tt showing clearly a difiorence in the oil of turpentine employed. The crystals, after being formed, may be freed from the uncrys- tallized liquid, by pressure between folds of blotting paper. They may be still farther purified by solution in alcohol, and repeated crystallizations. Dumas found that they coidd not be sublimed without losing muriatic acid, and that whc : ; •notified off carbonate of lime, they lose a notable portion of that aci '.. Thus purified, the compound is white, and crystallized in flexible needles. At the temperature of 68° it is so soft, that it may be kneaded between the fingers. But when cooled down to 52** it is brittle. It has a slight but aromatic taste, and its smell is similar to that of camphor, but not so strong. When heated it melts ; and, * This medicine was made by Pott in this manner : — 2 [jarts common salt 2 parts oil of turpentine were mixed together in a retort, and I part of concentrated sulphuric acid being added, the whole was distilled over the sand-bath. The liquid that came over was the medicine, t Trommsdorfs Jour, der Pharmacie, xi. 132, as quoted in Gehlen's Jour. vi. 459. X Ann. de Chim. li. 270. $ Gehlen's Jour. ii. 237. ||Ibid. vi. 470. 1[ Mem. d'Arcucii, ii. 29. *# Ann. de Chim. ct de Phys. xlvii. 225. ff Dumas, Ibid. Hi. 404. ' '\ Y'. wfwww u m. i < ' Ml 456 VOt.ATIf.K OII8. if the teini)orature he raised sufficiently Iiigh, it burns witli a lively flame, surrounded by a green border. It does not redden litmus paper, and the alcoholic solution of it is not precipitated by nitrate of silver. I^ut it undergoes decom- position when digested with the alkalies, muriatic acid being ab- stracted. It is very little soluble in water, though it conimunicates its peculiar smell to that liquid. Dilute nitric acid dues not attack it ; but it is dissolved by concentrated nitric acid. It is decomi)oaed when the alcoholic solution, is distilled live or six times oft' hydrate of lime. Artificial camphor, prejjared by M. Oppernmnn with great care at Strasburg, was found by him to be composed of "Carbon 72-81 or 25 atoms = 18-75 Hydrogen 8-98 or 18 atoms = 2-25 Muriatic acids 1*21 or 1 atom = 4'(i25 100-00* 25-025 But M. Dumas has shown that Oppermann's mode of ])urifying the artificial camphor, by subliming it off carbonate of lime, de- prived it of a portion of its muriatic acid. He purified it by pressure between folds of blotting paper, and repeated crystalliza- tions from alcohol. Thus prepared, it was composed of Carbon ()9-32 or 20 atoms = 15 Hydrogen 0-88 or 17 atoms = 2-125 Chlorine 20-80 or 1 atom = 4-5 Or 21-625 ^ 15 =: 2 ^ 4-()25 100 20 atoms carbon 16 atoms h'ydrogen 1 atom muriatic acid 2I-G25t Oppermann, when he decomposed artificial camphor, obtained a clear, transparent oil, not at all similar to oil of turpentine, and which he distinguished by the name of dadyl. It became solid and white at the temperature of 50°, but again melted when exposed to the heat of the hand. Suljjhuric acid changed it into a brown resinous matter. Fuming i itric acid and acetic acid did not dis- solve nor decompose it, showing that it differed completely from common oil of turpentine. Ether, alcohol, and bisulphuret of carbon dissolved it. It was subjected to an analysis, and found composed of Carbon 88-48 Hydrogen . . . . 11-52 camp! 313°, and til Dumaf to be capablJ perimel carbon [ bon -f.| agree detennil oil is al 100-00 But as ducted, * Ann. (Is C'liiin. ct tic I'hvs. xlvii. 'I'd'i. t Ibid. lii. 402 •Jj (HI, OF TUnPENTINF. 4;57 ely f it om- ah- ates tack osed Irate cave •ifying c, lic- it by talliza- taincd a line, and jolid and Iposed to brown Inot dis- ily from )f carbon loniposed 40-2, This 18 equivalent to lU atoms carbon 8 atoms hydroj^on = 7*5 or per cent. 88*24 = 1-0 _ _ ii-yo 8-5 lOO-OO Dumas found that the base which he al)stracted from artiHcial cam- phor, by freeing it completely from muriatic acid, was a liquid which, when properly purified, presented all the characters of oil of turpentine. It boiled when heated to 313°; and the specific gravity of its vapour was 4*83. Me subjected it to analysis, and obtained sensibly the same composition as Oppermann had done, namely, 10 atoms carbon . . . =7*5 8 atoms hydrogen . . . =1 8-.'> Oil of turpentine obtained by Blanchet and Sell, by distilling turpentine from the Vosges with water, and then rectifying it from chloride of calcium, had a specific gravity of 0*880, and its boiling point was 311°. It was composed of Carbon .... 88*54 Hydrogen . . . . 11*52 100*06 Numbers which almost coincide with the preceding analysis.* From the analysis of artificial camphor, it is not unlikely that pure oil of turpentine is C^" il'". It follows clearly from these experiments, not merely that oil of turpentine varies in its comjjosition, but that it contains two dis- tinct substances, both of which are capable of forming artificial camphor. Doubtless the liquid obtained by Dumas, which boils at 313°, is what constitutes the most volatile part of oil of turpentine, and that portion to which it is indebted for its peculiar smell. Dumas has distinguished it by the name of caniphme, conceiving it to be one of a numerous class of bodies which exists in volatile oils, capable of uniting with muriatic acid. It is evident, from his ex- periments, that it contains no oxygen, but is merely a compound of carbon and hydrogen. The result of his analysis is 10 atoms car- bon -f- 8 atoms hydrogen. The density of the vapour does not agree with this supposition. Could we depend upon the accurate determination of this density, we would be obliged to admit that the oil is a compound of 10 atoms carbon . . . 7*5 10 atoms hydrogen . . . 1*25 8*75 But as the analysis by means of oxide of copper, when rightly con- ducted, is susceptible of much greater precision than the method of ' Jour, de Phannacic, xx. '22o ; or Aiiimlcn dcr Pliarmacie, vi. iGU. f li i! tl i ■ I 408 VOLATILB OILS. taking tlio spcciHo gravity of va|K)ur(i, wo must abide by thu roaultH uf tluit analysis, and consider it aa u cunipound uf U) atoms carlxin 7 'ft or 20 carliun = 15 H atoirid hydrogen 1 Ki hydrogen = 2 8'5 17 Hcsides the two liqnids in oil of turpentine, which form artificial camphor, it is obvious that it must contain another li(|uid into which oxygen enters as a constituent, otherwise it could not, as it is well known to do, change potassium so rapidly into potash. Artificial camjihor is obviously a compound uf 1 atom oil of turpentine of 1113" = S'Ji 1 atom muriatic acid . . = 4'('>'25 1;M25 Acconling to Couerlie, the volatile oils aro composed of on oil destitute of smell, and of one or more connnonly two oils, to which the smell and taste of the oil is owing These may be removed by means of a fixed alkali, and then the inodorous oil may be pro- cured in a se)>arate state, lie assures us that he has separated an inodorous oil from oil of turpentine.* If this be so, it constitutes another substance in oil of turpentine. For it is obvious, that neither the camphene of Dumas, nor the solid nuitter obtained by Oppermann, possess the characters assigned by Couerbe to his oil. Oil of turpentine then is a compound of at least four or five different substances, some of which may be obtained in a separate state by the processes above indicated. MM. lioissenot and Perrot obtained from oil of turpentine, long exposed to the air, a transparent solid matter in rectangular jjrisms. It had neither taste nor smell ; fused at 302°, and was volatilized below 311". It is insoluble in cold, but very soluble in hot water. The same remark applies to ether. Nitric acid dissolves it cold without alteration, when hot decomposes it. Sulphuric acid dis- solves it, and assumes a fine red colour. Acetic acid dissolves it cold ; muriatic acid onlv when heated. Concentrated solu- tions oi potash and soda do not act on it, but diluted solutions dissolve it.f It was analyzed by MM. Dumas and Peligot, who obtained Carbon (i 2*99 or 20 atoms = 15 or per cent. 63*16 Hydrogen 11-41 or 22 atoms = 2-75 — — 11-58 Oxygen 25-00 or G atoms = (J — — 25-26 100-00 23-75 100-OOt A similar substance was observed in the oil from ocymum basilicum, and in the essential oil of cardomum minus. What is called oil of templin in Switzerland, is obtained from the pinus mugho, and appears, from the experiments of MM. Blanchet * Ann. de Cliini. et dc Thys. liii. 219. f Ibid, xxxii. 44ii. I Ibid. Ivii. 1334. Wehj Car Hyc showinl turpenf The) and foi * Jour OIL OP LBMONli. 4A<) kUltH iticial into t) it ia ' nil oil ) wliich cnioved be pro- •atetl an ;)8tltUte3 us, that ained by I his oil. r or five separate ;inc, long ir prisms. olatilized jot water. |cs it cold acid dis- dissolves Lied solu- solutions Ivined 63- 10 11-58 25-20 iToo-oot basilicum. Id from the [. Blanchet Ll. Ivii. !J34. and Sell, to ho identical with oil of liirpcntino. Thoy found its properties similar, and itA constituents, Carbon 88-07 Hydrogen . . . . 11-02 »9-09* obviously tho same as those of oil of turpentine. » SECTION II. — OF OIL OV LEMONS. This oil is extracted from the rind of the lemon, tho well known fruit of the citrua medica, or lemot^ tree. It is usually obtained by uxpressiun, and comes to us from tho south of Europe under tho name of essence of lemons. It is limpid, and has a light-yellow colour, which deepens by age. But when distilled over with water, if wo stop the jjrocess when 'i^A% of tho li(iuid has passed over, we obtain a colourless oil, having a specitic gravity of 0-847 at the temperature of 71 °j^, as determined by Saussure.f It does not become solid though cooled down to 4°. This oil has an agreeable odour, similar to that of lemons. Its boiling point has not been determined ; but in all probability it is nearly the same as that of oil of turpentine, or 313°. It dissolves in all proportions in absolute alcohol. But spirit of wine, of the specitic gravity 0-837, dissolves only 14 per cent, of it at the temperature of 00°. Blanchet and Sell analy/ud oil of lemons, and found its consti- tuents to be Carbon 80-73 Hydrogen .... 11-47 This approaches 10 atoms carbon 8 atoms hydrogen 98-20t 7-5 or per cent. 88-23 l-O — — 11-77 8-6 100-00 We have three other analyses of this oil, namely. Carbon Hydrogen showing together that its constitution is similar to that of oil of turpentine. Thenard first observed that this oil absorbs muriatic acid gas, and forms a crystalline substance similar to the artificial camphor • Jour, cic Pharmacie, xx. 226. + Ann. de Cliim. et de Phys. xiii. 263. X Ann. der Pharmacie, vi. 281. Sauuurc. Hermann. Dumas. 80-879 12-320 88-5 *ll-5 88-45 11-40 99-205 100 99-yi lit f( > I'. \ 460 VOLATILE OILS. i I*''! made in the same way with oil of turpentine.* The nature of the combination was afterwards investigated by Saussure. He found that at the temperature of 680°, oil of lemons absorbed 286 times its bulk of muriatic acid gas. During the absorption the oil becomes hot, and assumes a yellow colour, and increases about ^th in bulk, and about 0-49 in weight. At the temperature of 54° it concretes into a mass of crystals, which may be purified by pressure between folds of blotting paper .f The crystals are flat rectangular four-sided prisms. They have a weak odour, resembling that of thyme. They are heavier than water, and do not catch fire, unless they be strongly heated. They do not undergo decomposition when exposed to the atmosphere, and their volatility is not great. However, when long kept in a phial, they rise and are deposited in quadrangular prisms upon the sides of the glass. When heated to 106°, these crystals melt, and on cooling concrete into a crystalline mass, which is very brilliant. This compound may be distilled over without any striking de- composition, if we apply the heat rapidly ; but in a long-continued gentle heat decomposition takes place. It is insoluble in water, and has no perceptible taste. Alcohol of 0-806 dissolves, at the ordinary temperature of the atmosphere, the 16th part of its weight of it. But the solution is precipitated in crystals by the addition of water. It is not decomposed by cold caustic potash. Concentrated sul- phuric acid causes the disengagement of muriatic acid without the formation of any sulphurous acid, and slowly dissolves the oily base of the compound, assuming, at the same time, a yellow colour. Muriatic acid has no action on it whatever. Nitric acid of 1-39, applied cold, scarcely produces any sensible effervescence. 1 part of muriate ofcitrene (as this substance has been called by DumasJ) took 15 days to dissolve in 42 parts of nitric acid, of the specific gravity, 1-235. The nitrate of silver being mixed in excess with that solution, occasioned an abundant precipitate of chloride of sil- ver. The deposition continued to take place for several days.§ This compound has been lately analyzed with great care by Dumas, II and by Blanchet and Sell.^ They obtaii;ed from crystals, purified by compression, and repeated crystallizations in alcohol, Carbon Hydrogen Ciilorine This is equivalent to .Dumas. Blanchet and Sell. 58-025 8-625 33-350 57-49 8-54 33.81 100-000 99-84 or 10 atoms = or 9 atoms = or 1 atom = 7-5 or per cent. 57-14 1-125 — — 8-57 4-5 — — 34-29 13-125 100 * Mem. D'Arcueil, ii. 32, f Ann. de Chim. et de Phys. xiii. 265. I Ibid. lii. 49. § Ibid. xiii. 268. I| Ibid, iii. 405. T Ann. dcr I'tmrmacie, vi. 2S4. Thi^ distillal togethc exposu^ * AnnJ ORANGE-FLOWER OIL. 461 on !ss with ic of sll- •arc by irystals, ;oliol, It. 57-14 8-57 34-29 100 li. 265. 1405. 7*5 or per cent. 57-14 1 — 7-63 4-625 35-23 10 atoms carbon = 8 atoms hydrogen = 1 atom muriatic acid = 13-125 10000 Thus the composition of muriate of citrene is precisely the same as that of muriate of camphene, namely, 1 atom citrene . . . =8-5 1 atom muriatic acid . . = 4*625 13-125 Dumas found that the whole of oil of lemons could be converted into muriate of citrene. The base of this salt, or the citrene, may be obtained by means of potash or lime. When we distil repeatedly, we obtain a limpid colourless oil, possessing all the characters of oil of lemons. Dumas subjected it to analysis, and obtained Carbon . . 87*05 or 10-06 atoms Hydrogen . 11-53 or 8 atoms The analysis of Blanchet and Sell' Carbon . Hydrogen 98-58 gave 87-25 11-52 98-77 Thus it appears that the citrene, or pure oil of lemons, as we must consider it, is exactly similar, in its compositions, to camphijne or pure oil of turpentine. As Dumas has not given us the specific gravity of the vapour of oil of lemons, we cannot compare the above analysis with the theoretic result from specific gravity. Saussure found that oil of lemons, left in contact with oxygen gas over mercury for fifteen months, absorbed 143^ times its volume of that gas. The residual gas amounted to 0*2145, or rather more than jth of the oxygen gas absorbed. It was composed of Carbonic acid . . 61-9 volumes. Azotic . . . 25-2 — Oxygen . . . 16-8 — Hydrogen ... 10-8 — 114*7t SECTION III. OF ORANGE-FLOWER OIL. This oil, called neroli in the south of Europe, is extracted by the distilhition of the flowers of the citrus aurantinm, or orange tree, together with water. When newly prepared, it is yellow ; but by exposure to the sun, it may be made to assume a yellowish-red * Ann. tier Pharmacie, vi. 286. f Ann. de Chim. et de Phys. xlix. 234. !! ! 462 VOLATILE OILS. colour. It is very liquid, lighter than water, and possesses the agreeable odour which distinguishes the orange-ti'ee flowers. The aqueous solution of this oil, under the name oi orange-flower water, is used as an aromatic. It is obtained either by dissolving the oil in water, or by distilling the flowers along with water. During this distillation another substance passes over along with the oil, which possesses the property of assuming a red colour, when a few drops of sulphuric acid are added to the liquid. This property enables us to ascertain whether orange-flower water has been formed by dissolving the oil in water, or by distilling the flowers. In the former case, sulphuric acid does not render the liquid red: in the latter case it does. M. Plisson has shown that this oil, like the preceding, contains at least two different substances. He obtained a solid constituent from it, by adding alcohol, of the specific gravity 0*842 to the oil, till the whole was dissolved. A white precipitate begins to appear, sind continues for some time to fall. Indeed the alcoholic solution continues for days to deposit whites scales. This precipitate is purified by washing it in alcohol, dissolving it in ether, and precipitating it a second time by means of alcohol. When the ethereal solution is evaporated spontaneously, we obtain the white matter in crystals. The recent oil furnishes about 1 per cent, of this substance ; but the quantity diminishes with the age of the oil. The crystals of this substance are in scales, lustre pearly, taste- less, and destitute of smell, and having no action on vegetable blues. They soften at 122°, and melt at 131°. On cooling they concrete into a translucent mass, having the aspect and fracture of wax. The specific gravity in this state, at 63°^, is 0*913. In vacuo, it may be volatilized easily without alteration. It is insoluble in water ; but dissolves in 60 times its weight of boiling alcohol, of the specific gravity 0*800, and is deposited in scales when the solution cools. It dissolves readily in hot oil of turpentine, and is deposited when the solution cools in transparent plates. Sulphuric ether is its best solvent. Sulphuric acid does not attack it while cold ; but when heated, sulphurous acid is formed, and the white substance is charred. Niti'ic acid seems to have no action on it, even when assisted by heat ; the same remark applies to muriatic acid. M. Plisson could not succeed in converting this substance into a soap. He considers it as one of the constituents of oil of orange flowers, and has given it the name of aurade; considering it as a fatty substance analagous to amhrein, myricin, ethal, and cerain, all of which arc fatty bodies, unalterable by alcohol, and not capable of being converted into soap by means of potash.* Its constituents, according to the analysis of Henry and Plisson, are * Ann. do Chim. et dc Phvs. xl. 83. Jour. OIL OF JUNIPER. 463 Me ver itig ter. vith our, rhis ha3 the ■ the ita'ms from ill the , and lution pitate ', and ;n the ! white • cent, age of taste- 5 blues, oncrete ■ wax. acuo, it eight of sited in oil of sparent cid does formed, have no L applies le into a orange it as a [rain, all capable Plisson, )t Carbon Hydrogen Oxygen 83-7() 15-0892 1-1508 100-0000* This (if the oxygen be not accidental) gives the following formula: 97 atoms carbon =72-75 105 atoms hydrogen = 13*125 1 atom oxygen = 1-00 86-875 SECTION IV. OF JUNIPER BERRY OIL. This oil is obtained by distilling pounded juniper berries along with water. It is limpid and colourless, or having a slight shade of yellow. Its specific gravity is 0-911. It has the well known smell and taste of juniper berries. It is very little soluble in water, and scarcely more so in alcohol. Spirits impregnated with it consti- tute the well known Geneva of the Dutch. The distillers at Schie- dam were formerly in the habit of carrying over annually a ship load of juniper berries from Inverness, for the use of their distilleries. Oil of juniper is employed in medicine, and considered as a diuretic. It is said sometimes to be adulterated by oil of turpentine. This fraud may be easily detected by taking the specific gravity of the oil, which is lighter than usual, when mixed with oil of turpentine. M. Blanchet has extracted two different oils from juniper berries.f 8 pounds of unripe juniper berries, distilled with salt water, fur- nished 2 ounces of oil, which, by cautious redistillation, was sepa- rated into a more and a less volatile oil. The same quantity of ripe berries furnished only half an ounce of oil, which was all of the less volatile variety. The more volatile oil is colourless. Has the smell of juniper berries, with something resembling that of pine oil. When it is shaken with salt water, a crystallized substance precipitates, probably a hydrate of the oil. When a drop of this oil, rectified on quicklime, and freed from water by chloride of calcium, is let fall upon paper, it is almost immediately converted into a resin. Its specific gravity is 0-8392, and it boils at 31 1°. It dissolves with difficulty in alco- hol of 0-85. When mixed with its own weight of anhydrous alco- hol, it forms a transparent liquid, from which, however, it gradually separates. It dissolves in ether, and may be mixed in all propor- tions with ether, free from alcohol. It was analyzed by Blanchet,$ who obtained Carbon 87-21 Hydrogen . . . . 11-52 98-73 * Jour, de Pharmacie, xvii. 430. f Poggendorf's Aimalen, xxxiii. 39. J Ann. der Pliarni. vii. ICG. II IJ ! < :i! 464 VOLATILE OILS. ,P i h :H I i ^ If iu If 1 The less volatile oil cannot be obtained colourless. Its specific gravity is 0*8784, and it boils at 401°. It dissolves with difficulty in alcohol of 0*85, and requires 8 times its weight of anhydrous al- cohol to dissolve it. It dissolves in ether, does not effervesce with iodine, and is not decomposed by potassium. It was analyzed by Blanchet, and found isomeric with the more volatile oil- These two oils have the same composition as oil of turpentine ; namely, C" UK When caustic potash is added to the water distilled over with these oils, a crystallized substance falls, which is a hydrate of the oil, composed of C"* H* + 2 atoms water. When a little iodine is added to a few drops of oil of juniper, much heat is evolved, and yellowish-violet vapours are exhaled. The residue, when cold, was fluid, had a yellowish-brown colour, and retained the smell of the oil.* SECTION v. — OF OIL OF PEPPER. This oil is extracfed from common pepper {piper nigrwn). When newly extracted it is limpid and colourless ; but becomes gradually yellow. It is lighter than water. It has the smell, but not the taste of pepper. It is composed, according to the analysis of Dumas, of Carbon 87'9 or 10 atoms = 7-5 or per cent. 88-23 Hydrogen II "7 or 8 atoms = 1 — — 11*77 99-r)t 8-5 100-00 So that its constitution agrees with that of oil of turpentine and oil of lemons. SECTION VI. — OF OIL OF SABINE. It is obtained from the leaves of the juniperus sabina. Limpid. Has the odour and flavour of sabine. This plant furnishes a great deal of oil. Sabine owes its diuretic properties to this oil. It was analyzed by Dumas, and found to be a compound of 10 atoms carbon =7*5 or per cent. 88-23 8 atoms hydrogen =1*0 — — 11*77 8*5 loot Iodine acts violently on it. Much heat is evolved, and yellowish and violet vapours given out. A resinous mass, of a deep brownish- red, remained. § • Hashoff, Jour, de Pharmacie, xvii. 112. It appears hom the experiments of M. Bonastre, that when the rasped wood of the Juniperus Virginiana is distilled with water, a volatile oil is obtained, which is liquid (after being filtered), but thick and glutinous. It yields crystals when cooled down, or when a crystal is put into it. See Jour, de Pharmacie, xxiii. 177. f Jour.de Pliarmacie, xxi. 192. X I'""'- x'*'- '^3. ^'i IhibhoJl', Jour, do Pharmacie, xvii. li'J. Ti aronn clove Ocea deepe well citic ^, has Jail vary k mixing passes I ing wii withoui carbon] Whel phuric ^nd pos cih'c It is volatile turpentil J-ated h) it deposJ 's obtain] * Jour. d| \ PojrgI OIL OF CLOVES. 465 ulty sal- with more itine ; f with of the iniper, iclialetl. colour, When radually , not the 23 77 00 ne and oil Limpid' les a great (il. Indof . yellowish ibrownish- Ixperiments of I filtered), l>"t Ihcii a. crystal 1 93. SECTION VI. — OF OIL OF THUYA OCCIDENTALIS. The thui/a occcidentalis is a native of Canada, and has been long cultivated in our shrubbries. M. Bonastre extracted a volatile oil from it, by distilling its leaves along with water.* This oil is liquid, transparent, lighter than water, and has a light yellow colour, with a shade of green. When rectified it becomes lighter, but does not lose its colour. Its taste is strong, analagous to that of camphor, and its smell resembles that of tansey. Concen- trated sulphuric acid renders it brown, and chars it. Nitric acid deepens its colour, but does not set it on tire. Muriatic acid ren- ders it muddy, and increases its odour. Acetic acid dissolves about ygth of its weight of it. DIVISION II.— OF VOLATILE OILS CONTAINING OXYGEN. As only a very few of these oils have been subjected to a chemi- cal analysis, the greater number of those which occur in this divi- sion have been placed in it merely from analogy. Several of them no doubt belong to the first division. SECTION I. — OF OIL OF CLOVES. This oil is extracted from the unripe fruit of the caryophyllus aromaticus, called by modern botanists eugenia caryophyllata, or clove tree, a plant which is a native of the islands in the Indian Ocean. It is colourless or light yellow when fresh, but the colour deepens by keeping, and becomes at last a dark brown. It has the well known smell of cloves, and a hot disagreeable taste. Its spe- cific gravity, according to Dr Lewis, is 1*034; but Bonastre, who has lately subjected this oil to numerous experiments,! found it to vary from 1*055 to 1*06 1. M. Ettling found it a mixture of two oils, easily separated by mixing the oil with potash ley and distilling. A colourless oil passes over, having a specific gravity of 0*918, incapable of combin- ing with bases, but absorbing muriatic acid in great abundance, without yielding a crystalline compound. It is composed of 10 atoms carbon, and 8 atoms hydrogen, without any oxygen. When the residue is mixed with an excess of phosphoric or sul- phuric acid, the other oil passes over. It reddens litmus paper, and possesses the characters of an acid. It is colourless, has a spe- cific gravity of 1*079, and boils at 4G9°^.| It is one of the least volatile, and most difficult to distil of all the volatile oils. M. Bonastre found, that when oil of cloves and oil of turpentine are mixed together, the latter may be completely sepa- rated by a graduated distillation.§ When kept for a certain time, it deposits a solid crystalline matter. Seemingly the same substance is obtained when pounded cloves are boiled in alcohol, and the solu- * Jour, de Pharumcie, xi. 15G. f ^^"'i- tie Cliiin. et de I'iiys. xxxv. 274. \ Pojrgciulorfs Annalcii, xxxi. 62G. ^ Jour, de I'hariuacie, xiv. 579. 2h : )\ 466 VOLATILE OILS. I I II ' ! tion is filtered while hot. On cooling it deposits brilliant white crystals, which have neither taste nor smell. They are soluble in ether, but insoluble in alkalies, and incapable of forming soap. When gently heated they sublime unaltered. Oil of cloves is soluble in alcohol, ether, and concentrated acetic acid. It may be exposed for hours to a cold of 4% without becom- ing solid. It absorbs chlorine gas, and becomes first green, and then brown. In this state it contains muriatic acid, iind is partially converted into resin. Nitric acid gives it a red colour, and when the mixture is heated oxalic acid is formed. If we mix it with about ^d of its weight of sulphuric acid, added by little and little, to pre- vent the oil from becoming hot, we obtain an acid liquid, at the bottom of which we find a purple-coloured resin. This resin, after being washed, is hard and brittle. Alcohol dissolves it, assuming a red colour, and water throws down the resin from the solution, having a blood-red colour. It dissolves also in ether. When the acid liquid is diluted with water, a dark-coloured oil precipitates, which, when distilled with water, gives a limpid vola- tile oil, leaving a portion of purple-coloured resin. When we agitate together a concentrated solution of caustic soda and oil of cloves in equal volumes, the mixture speedily thickens, and fine laminated crystals are deposited. If we now pour water into the mixture, and distil, a small quantity of a volatile oil passes over, which differs from oil of cloves by its smell and its chemical properties. During the cooling, the liquid remaining in the retort deposits a great number of crystalline needles, which, when separated by expression from the alkaline liquid, are nearly destitute of smell, but have a taste at once alkaline, and burning like that of the oil. These crystals dissolve in from 10 to 12 times their weight of cold water. The oil of cloves combines in a similar manner with other bases, so as to show decidedly the characters of an acid body. The fol- lowing are the results which Bonastre obtained : — 2. Ammoniated clove oil. When a current of ammoniacal gas is passed through the oil, it is absorbed, and the oil becomes inspissated. This matter remains solid as long as the vessel containing it is corked, but when opened it becomes liquid. It solidifies again when we cork the vessel, and this phenomenon may be repeated at plea- sure.* If we agitate oil of cloves with liquid ammonia, a granular deep- coloured matter is deposited, which does not dissolve, and allows the ammonia to escape when left exposed to the air. 3. Clove-oil potash. When clove oil is treated by potash in the same way as has been described by soda, a combination takes place, which separates in white plates, having the taste of the oil, and re- acting strongly as an alkali. When dried at 212°, they contain between 11 '69 and 12 per cent, of potash. These crystals may be dissolved in water, and crystallized a second time, though they are ' Karls, Pd-igcadoif's Aiiriiilcn, x. 609. 7. clove plete 8. sulph sulphi gradi 9. boiJedl yellowf ^ater.l coinpoj tligeste 10. soda ar but by] The make a I suppJiet CLOVE OIL. 467 le in ioap. icetic ecom- i, and TtiaUy L when I about to pre- , at the a, after ssumlng jolution, jured oU pid vola- istic soda thickens, ,our water oil passes s chemical the retort 1 separated te of smell, )f the oil. weight 01 ,ther bases. The fol- iacal gas is inspissated. aining it is again when ited at plea- mular deep- atid allows lotash in the takes place, b oil, and re- [they contain Utals may be Lgh they are partly decomposed during the process. Nitric acid gives them a tine red colour. With water, alcohol, and ether, they behave as clove-oil soda. 4. Clove-oil barytes. When clovf oil is heated, with barytes water, d combination takes place, especially if assisted by heat. On cooling, small crystalline needleS are deposited. These crystals have a pearly lustre. They have the taste and the smell of clove oil. They are composed of Barytes, 30'3 Clove oil, .... 69*7 100-0 If we suppose the barytes saturated in this compound, the atomic weight of clove oil would be 21*85. Nitric acid gives this compound a yellow colour. With the per- salts of iron it strikes a lilac or violet colour. It is somewhat soluble in cold, and much more soluble in hot water. When decom- posed by sulphuric acid, it leaves a brown-coloured clove oil, which after being distilled over gives a red colour to litmus paper. 5. Clove-oil strontian is made in the same way, and possesses properties similar to those of clove-oil barytes. G. Clove-oil lime. When 1 part of oil, and 2 parts lime, are boiled together in water, we obtain a greenish-white liquid, not becoming muddy on cooling. By evaporation we obtain clove-oil lime in the state of a yellow crust, which must be removed from time to time if we wish to continue the evaporation. It has a weak taste of clove oil, when treated with nitric acid becomes safron-yel- low. With sulphuric acid it effervesces and becomes wine-red. It is soluble in 235 times its weight of water. 7. Clove-oil magnesia. Calcined magnesia, when digested with clove oil, forms a white hard compound, not crystallizable, and com- pletely insoluble in water, whether cold or hot. 8. Clove-oil iron. When clove-oil potash or soda is boiled with sulphate of iron, a blue-coloured magma is produced. With the sulphated peroxide of iron the precipitate is red, but becomes gradually violet and then blue. 9. Clove-oil lead. When protoxide of lead and clove oil are boiled together in water, renewing the liquid as it evaporates, a yellow-coloured adhesive mass is obtained, which is insoluble in water. When dried in the open air, it becomes friable. A similar compound is formed when clove oil, potash and acetate of lead are digested together. 10. Clove-oil copper. This compound is precipitated when clove-oil soda and sulphate of copper are mixed together. It is at liru brown, but by half an hour's boiling becomes sky-blue or verdigris-green.* The marked acid properties of this oil induced M. Dumas to make a set of experiments to determine its composition. He was supplied witli the pure oil of cloves by M. Boriastre, and in order * Bonastrp, Ann. de Chiin. et do Phys. xxxv. 274. I !( 468 VOLATILE OILS. «d II hi = i ' ' 1 ! - i to deprive it of water, it was rectified over chloride of calcium. His attempts to determine its atomic weif^lit by combining it with pot- ash or soda were unsuccessful. The crystals always retained a great quantity of unconibined alkali from which it was impossible to free them. But he found no difficulty in saturating the oil with ammoniacal gas. 0*653 grammes of this oil absorbed 83 cubic centimetres of ammoniacal gas at the temperature of 32°, and under a pressure of 29*92 inches of mercury. Hence it follows that 100 parts of the oil absorb (at the temperature of 60°) 9'7 parts of am- monia, so that ammoniatcd clove oil is composed of Clove oil, . . 100 or 21*9 Ammonia, . . 9*7 or 2*125 This would make the atomic weigrht of clove oil 21*9, or very nearly 22. Dumas analyzed clove oil by means of oxide of copper, and obtained Carbon 69*93 or 20 atoms =15 or per cent. 69*36 Hydrogen 7*89 or 13 atoms = 1*625— — 7*52 22*18 or 5 atoms = 5 — — 23*12 Oxygen 100*00* 21*625 100 Ettling subjected to analysis the acid oil extracted from cloves, and obtained Carbon 71*64 or 24 atoms = 18 or per cent. 72*36 Hydrogen 7*44 or 15 atoms = 1*875 — — 7*54 Oxygen 20*92 or 5 atoms =5 — — 20*10 100*00 24*875 100*00 M. Ettling endeavoured to find the atomic weight of this oil by com- bining it with bases. But the experiment was attended with unex- pected difficulties. The best result was clove-oil lead composed of Acid . . . 37-39 or 25*24 Oxide of lead . 62*61 or 42 = 14 X 3 100*00 Supposing the salt to be a trisclove-oil lead, the atomic weight would be 25*24. t It appears from this analysis that oil of cloves differs from oil of turpentine, oil of lemons, and oil of orange flowers, all of which are lighter than water by containing a notable quantity of oxygen. Dumas assures us that a similar constitution belongs to all those volatile oils which are heavier than water. They all possess acid properties, and doubtless these acid ])roperties they owe to the oxygen which they contain. Oil of turpentine, and oil of lemons, on the other hand, that portion of them at least which combines with muriatic acid, contain no oxvjjen. Hence it seems reasonable to conclude that those volatile oils which possess the characters of bases, and which are all lighter than water, contain no oxygen ; but are simple compounds of carbon and hydrogen. * Ann. 'Ic rhim, et fie Phvs. liii. 164. \ rofrucndort's Ainalen, xxxi. .529. f 'ormer OIL OF UITTEK ALMONDS. 401) His I pon- ied a bleto I witVi culnc at 100 of am- or very obtained 36 •52 •12 ) )m cloves, 72-3() 7-54 20-10 00-00 |oU by com- Avitb unex- omposed of 3inic wcigl^t i from oil oi of wliicli are of oxygen. to all tbosc possess acvd I oNve to the 111 of lemons, Icb combines Vs reasonable Icbaractersot , oxygen ; but Ik'D, K^iXl .V •?9. M. lionastre observed a crystallized substance in oil of cloves.* It was in thin, white, nearly, transparent scales. When kept it gradually assumed a yellow colour. It is very soluble in alcohol and ether. It has the smell and the taste of cloves, but far weaker than clove oil. Wlien placed in contact with nitric acid, it imme- diately assumes a red colour. It was analyzed by Dumas who found it to bo clove oil combined with an atom of water, or an hydrate of clove oil. Or its composition may be represented by the formula C^" H'"' 0» + HO. lionastre proposes to distinguish this substance by the name of eugenin. But the term hydrate of clove oil would be better, as it would recal to mind its composition. SECTION II OF OIL OF CINNAMON. Described under cinnamic acid in the Chapter on acids. SECTION III OF VOLATILE OIL OF HITTER ALMONDS. This oil may be obtained by distilling bitter almonds with water. When the fixed oil of bitter almonds is obtained by expression, without the application of heat, it contains no trace of the volatile oil. Reduce the matter of bitter almonds thus freed from fixed oil to a coarse powder, place it loosely upon a seirce at the top of an alembic containing water, and distil off the water ; the vapour of the water passing through the marc of the almonds, carries along with it the volatile oil. The first portions of water that pass over are limpid, and the oil which they contain falls to the bottom of the liquid. The subsequent portions of water are milky and less charged with oil. VVhen the water begins to distil over limpid and colourless, it is a proof that the oil has all been volatillized.t Neither the oil nor the water reddens vegetable blues. The oil which comes over first has so strong an odour that in this respect it has a greater resemblance to cyanogen than to hydro- cyanic acid. The first limpid portions of water that come over contain a good deal of the oil in solution. Oil of bitter almonds has a golden-yellow colour, is heavier than water, and has a strong but agreeable odour of hydrocyanic acid. When exposed to the eir, it absorbs oxygen, and deposits a great number of white crystals, t Robiquet found that this oil is a com- pound or mixture of two different oils. The one, which comes first over is more volatile and contains hydrocyanic acid, which renders it very poisonous. The other oil, which comes over last, is not poisonous, absorbs oxygen from the air, and assumes a crys- talline form.§ Vogel showed that oil of bitter almonds contains abundance of * Jour, de Pharmucie, xx. 563. t Robiquet and Boutron-Charlard, Ann. de Cliim. et de Phys. xliv. 364. X Is it not likely that these crystals are the nmyydalic acid, described in a former Chapter of this work ? Stange considered them as benzoic acid, to which the aniygdalic has a striking resemblance. § .Ann. de Chim. et de Phvs. xxi. 250. 1 I I li ij '^ r. IHI m n ii lA • 470 VOLATILE OILS. hydrocyanic acid.* If we dissolve 100 parts of this oil in alcohol, and mix the liciuid with an alcoholic solution of potash, and then throw down the oil by water, we obtain, accordiiifj; to Schradcr, a Juantity of cyanodide of potassium capable of forming 22^ parts of 'russian-blue. Having kept the oil tor throe years, and then sub- jected it to the same treatment, he obtained 17*(> parts of Prussian- blue. Vogel found that the oil of bitter-almonds, when deprived of all the hydrocyanic acid which it contains, is still characterized by the usual smell and taste, and acts as a poison nearly as violently as when it contained the hydrocyanic acid.f It is obvious from the experhnents of llobiquet, that the portion of the oil which absorbs oxygen and becomes concrete, is not poisonous, and Stange assures us tliat he gave the first portions of the oil, after agitating them with barytes water, both to dogs and cats without injury, though it still retained its peculiar taste and odour| ; but from his own state- ment it is pretty obvious that it consisted chielly of the last portions distilled. For he assures us that a few minutes' exposure to the air was sufficient to convert it into a mass of crystals. Oil of bitter almonds, accordli.g to Robicjnet and Boutron-Char- lard, absorbs chlorine gas, and deposits crystals, no doubt, of amygdalic acid. The liquid from which these crystals have fallen, has the smell of chloride of cyanogen, and mixes readily with water. When we heat this liquid, muriatic acid is disengaged, and a crys- tallized acid (considered as benzoic) begins to be deposited. It is obvious from this that the acid does not exist ready formed in the oil, but is produced by its absorption of oxygen, and the decompo- sition of water, the hydrogen of whicli converts the chlorine into muriatic acid. The oil of bitter almonds combines with the alkalies. Robiquet and Boutron-Charlard mixed the oil with caustic pot- ash, taking care to fill a bottle, which was well stopped, with the mixture. It was kept in this state for a month, being well agitated very frequently. The oil under this treatment was completely transformed into a mass of small crystals, insoluble in the alkaline liquid, and composed of the oil and potash united. These crystals, dissolved in water forming a milky liquid, which when distilled yielded an oil almost destitute of smell. The same chemists assure us that when oil of bitter almonds is treated with an alkali, while in contact with the atmosphere, abun- dance of benzoate of potash is formed. This oil absorbs abundance of ammoniacal gas, and forms a solid compound, which may be reduced to powder, and exposed to the air without losing the ammonia which it contains. § When this oil is treated with nitric acid, benzoic acid is formed, but in much smaller quantity than when the oil is exposed to the oxidation of the atmosphere. When oil of bitter almonds is preserved for a long time, a peculiar * Ann. de Chim. ct ile Phys. xix. 221. f Ibid. J Repert. xiv. 329. § Karls, Poggendorf's Annalen. x. 610. But, on, OK niTTKU AI.MONDS. 471 L\»cn sr, a t8 of sub- jsian- ir'vveil prized >\eut\y )m t\ic ,\)9orb9 vssurcs r tbcm ouffb it n state- povtions ) tbc aiv )n-CUav- loubt, of ve fallen, \tb water. »d a crys- ed. It IS ed in tbe decomvo- lorine into austic pot- 1, witb tbe ell agitated completely tbe alkaline ;se crystals, ^en distdled f almoT^^* is l)bere, abun- Lrms a solid losed to tbe Id is formed, posed to tbe ne, a peculiar Lett. xiv. 329. substance ia formed in it which rciimitK? behind when mo distil tlio oil along with water. This suhstunce was exuniined by lionastre. It is not volatile ; it dissolves in alcohol, and crystalli/es from that solution in 3- or (J-sided prisms. It is little soluble in water ; melts when heated, and burns, giving out at the same time an urouuitic odour. Uobiquct and Houtron-Charlard have endeavoured to prove that the oil of bitter nhnonds does not exist in the almonds, but is formed during the process of distillation. When the ware of bitter almonds is digested in ether, no volatile oil is obtained. Hut if we dilute this marc with water, and then digest it again in ether, the oil of bitter aluionds is now obtained in solution in the ether. If we treat the marc first with ether, then with alcohol, and then with water, we obtain no trace of volatile oil. The alcohol employed contains in solution a crystalline body, to which Kobiquet and IJoutron-Charlard, who discovered it, have given the name of amygdalin. It has a sweet taste, leaving upon the palate an impression of bitterness, somewhat similar to the taste of bitter-almonds. It is destitute of smell. It is not volatile either by itself or when mixed with other substances likely to promote its volatility. When heated in a glass tube it swells, emits at first the odour of caramel ; while towards the end of the calcinatiouj that of the blos- soms of the mespilus oxyacanthus, or common hawthorn is perceptible. It is not altered by exposure to the air. Chlorine seems to have no action on it while both are dry ; but when moisture is present the amygdalin swells out, remains insoluble in water, and assumes the appearance of a resin. Alcohol is incapable of dissolving amygdalin. When heated with a solution of caustic potash, it gives out a strong smell of ammonia, and the solution contains no trace of prussic acid. It is obvious from this that azote enters into its com- position. When treated with nitric acid, some benzoic acid ia formed ; but the quantity obtained in this way can only be small, as nitric acid has the property of destroying benzoic acid in proportion as it is formed. It was subjected to a chemical analysis by MM. Henry, junior, and Plisson, who obtained the following result : — Carbon 58-5616 or 39 atoms = 29*25 or per cent. 59*09 Hydrogen 7*0857 or 28 atoms =3*5 — — 7*07 Azote 3*6288 or 1 atom =1*75 — — 3*63 Oxygen 30*7239 or 15 atoms = 15*0 — — 30*21 10000 100*0000 49*5 But, from the more recent examination by Liebig, it consists of 40 atoms carbon = 30 or per cent. 52*63 26 atoms hydrogen = 3*25 — — 5*70 1 atom azote =1*75 — — 3*07 22 atoms oxygen =22 _ — 38*60 100 472 VOI.ATII.r. OII.N. fl; I li fM! Oil of hitter nlinoiDlri in pruimrcil in Kranco in ^roat ([(inntitii>i4 fur |it>rfuiiiiii^ soap. HonnHtro iiiruriiiti iih that a porriiiiior in I'arit* propnrt'8 every year three hundred weight of it. Oil of hitter ahnonds, a8 analyzed hy Liehi^, is <'oii.poHe 2 atoms oxyj^en =2 — — ir)"0!> 13-2r} 100 SKCTION IV. — OF OIL OF MKIKiAMOTK. It has a smell analogous to that of oranges, and is ol)tained fro i the rine fruit of the ritrus hcn/amimn. It is limpid, vellowi'h, muI fluid, lias a specific gravity of O'HHH. It becomes soliil a Urtif l)eli»\v JJ2°. It is nuich used as a perfume; hut has not hitherio been iil)- jeetcd to n chemical examination. SECTION V. — OF OIL OF ROsES. This oil, called otfn or ottar of roses, is obtained by distilling the petals of the rosa ceutifulia along with wiifer. The roses in this country, and even in France, yield so little oil that it hardly pays the expense of the process. Those in Egypt arc j)robably richer in oil, as it is from that quarter chiefly, and from India, that otto of roses comes. Oil of ro8(!8 is nearly colourless, and has the odour of roses, of course too rut h concentrated to be agreeable; but constituting a delicious jiorfume. The speciflc gravity of Persian oil of roses is according- to (^bardin 0*872, and tliat ot French oil 0*807. When cooled below 80° it congeals into a substance like butter. This melts at 84° into a limpid oil. At the temperature of 57°, 1000 parts of alcohol (of 0'80(j) dissolve only 7^, and at 72°, 33 parts of this oil. It is composed of two oils, one liquid and the other solid, the latter of which is destitute of smell. It is obtained by freezing the oil, an'' compressing it while solid between folds of blotting paper. It constitutes crystalline plates, which melt at about 9.5°, and on cooling congeal into large colourless transparent crystals. It is very little soluble in alcohi I. Blancne> i has analyzed this oil auJ ':)i)tained Carbon 74-07 or 23 a' m -r. V: > or p. .nt. 74*59 Hydrogen 12*13 or 23 aLoius= 2*875 — — 12*43 Oxygen 13*80 or 3 atoms = 3*000 — -- 12*98 100*00* 23-125 100 Blanchct also analyzed the pure crystallized stearin from oil of rof jij. It becomes solid when cooled down to 93°. It boils be- tvsn 536° and 572°. It then smokes like boiling fixed oil, but ui) Jergoes no alteration. Its constituents were found to be * Ann. der Pliaruiacie, vii. 154. Th able menth\ arornal hi spcf t'ooledl merely oil yie^ permit gatherJ l^hel water. Th.J ^'ompos •a,J oil. OF I'KPrKHMINT, 473 iticn f , in t\ii9 dly \'ay8 ly richer tWt otto roses, of ir. ituting a f rosea is When This .. , 1000 I3 parts of Hier solid* [y freezing \i blotting ibout 95°, ft crystals. I74-59 ll2-43 12-98 loo Ifrom oil of It boils be- ted oil, but ,be Hydrogen 81'18 14-40 95-r>8« Saussuru »'ho also aiuilv/od this stearin oMainod Carbon '. . . . Hti-U'A Hydri.^riin . . . , 14-889 l01-<>32 If wo 8up|»oflc it to be a compound (»f I atom cairbon + I atom liydrojjcn, its constituents would be 1 atom carbon 0-75 or per cent. 85-72 1 atom hydroj,a'n 0-l2r> — 14-28 0-875 100-00 Numbers which approach pretty nearly to the result obtained hy Saussure. 'I'lierc is probably a typographical error in the numbers given by Rlanchet. rie himself states the ci uposiirlon Carbon .... 85-8() Hydrogen .... 14-40 1 00-32 Ihit his analysis will not admit of these numbers. SECTION VI. — OF OIL OF JONgUILl.E. Robiquet has shown that the smell of the petals of the narcissus jonquillay is owing to the presence of a volntile oil, which cannot be extracted in the usual way ; but is separated when ♦ho flowers are digested in ether, and that liquid distilled ott*. It hfi - the fragrance of the Jonquille ; but is very easily altered in its nati. cf SECTION VII. — OF OIL OF PEPPERMINT. This is one of the few volatile oils that is prepared in consider- able quantity in this country. It is extracted from the i oaves of the mentha piperita or common peppermint. It has a ycllo\v colour, an aromatic and cooling taste, and the well known odour of [ oppermint. \\i specific gravity is 0-92. The American oil yields cr\ totals when cooled down, which Dumas has shown to differ from camphor, merely by containing two additional atoms of hydrogen. European oil yields no camphor. Giese assures us, that the only oil of pep- permint which yields camphor, is that prepared from the dried plant gathered when in flower. The aqueous solution of this oil, under the name of peppermint water, is occasionally used in medicine. This oil was analyzed by MM. Blanchet and Sell, who found it composed of * Ann. (Icr Phar(nae om a bot L ether, elevation .\ V. lea, a plant ur, is very ntic gravity itest. It IS pliol of tlie ireiglit of it. ic acid, the of a cliemi- ition of the L the acid in of the pure ,\1 under the [gen gas, for ; of that gas. than a third Vg or common 'by the name liivacie, xvii. 112. of oleum anthos. It is limpid like water, and except in its smell, which is that of rosemary, it has a good deal of resemblance to oil of turpentine. Its specific gravity is 0*934, but by rectification Saussure obtained it as light as 0'8886. It boils at 329". It is soluble in all proportions in alcohol of 0*83 ; but it requires 40 times its weight of alcohol ta dissolve it. When kept in imperfectly- stopped phials, it gradually deposits crystals, which have been con- sidered as camphor ; but how far they possess the properties and constitution of camphor, has not been determined by experiment. This oil is sometimes adulterated witjh oil of turpentine. To discover the fraud, we have have only to mix it with its own bulk of alcohol, which will dissolve the oil of rosemary, and set the oil of turpentine at liberty. SECTION X. OF OIL OF ANISE. It is extracted from the seeds of the pimpinella anisum. It is colourless, or slightly tinged yellow, and has the odour and taste of anise seeds. It becomes gradually solid when kept at the tempera- ture of 50°. The camphor which it deposits will be described in a subsequent section of this chapter. Its specific gravity at 78°, was found by Saussure to be, 0*9857. It is soluble in all proportions in alcohol of 0*806, but alcohol of 0*84 dissolves only 0*42 of its weight of it. Oil of anise analyzed by MM. Blanchet and Sell, was composed of Carbon .... 80*24 Hydrogen .... 8*55 Oxygen . . . . 11*21 found 100-00 And the stearin from the same oil of Carbon .... . 80*71 Hydrogen 8*12 Oxygen .... . 11*17 100*00* This gives us 1 atoms carbon = 7*5 or per cent. 81*08 6 atoms hydrogen =0*75 — 8-11 1 atom oxygen =1*0 — — 10*81 9*25 100*00 The stearin was obtained by cooling down the oil to 32°, and then subjecting the solid matter to pressure, between folds of blotting paper. It was then dissolved in hot alcohol of 0-818, and crystal- lized. The crystals were freed fromalcohol by fusion. This stearin was heavier than water. It melted when heated to 61°, and boiled at 428°. Not so soluble in alcohol as the elain of the same oil. * Ann. der riiarm. vi. 287. ' >' m i A 476 VOLATILE OILS. n i'liii Kill /, i ' h ■ V- :i J n SECTION X. OF OIL OF CAJEPUT. This oil is prepared in the East Indies, by distilling along with water the dry leaves of the melakuca leucadendron. It is said to be chiefly prepared at Banda. It has been used in India from time immemorial as a medicine, and was imported into Europe by the Dutch, and employed extensively in Germany before the plant from which it is obtained was known. This was first discovered by Lin- naeus in 1772. Cajeput oil has a green colour. It is very fluid, and has a spe- cific gravity, varying from 0*914 to 0-9274. Its taste is hot, and its smell strong and rather disagreeable. It is entirely soluble in alcohol. According to Leverkiihn it consists of two oils which may be sei)arated by distillation. Seven-eighths of the oil employed comes over colourless, and has a specific gravity of 0*897 ; then a green oil distils over more slowly, having a specific gravity of 0*920 and having a weaker odour, but a more acrid taste. According to Blanchet, it boils at 343°i. When heated to 248°, its green colour disappears, and it comes over colourless. What comes over first has a specific gravity of 0*9196, and boils at 343°^. Potassium is converted by it into potash. It dissolves iodine with- out eftervescence. Sulphuric acid changes its colour to yellow. Nitric acid does not alter it. The constituents of this oil are (as determined by Blanchet*), 10 atoms carbon = 7*5 or per cent. 77*92 9 atoms hydrogen = 1*125 — — 11*69 I atom oxygen =1*0 — — 10*39 9*625 100*00 So that it difl'ers from oil of turpentine, and of juniper, by contain- ing an additional atom of water. It is much used as a medicine, both externally and internally in India. Externally, it seems to act as a stimulant, and is found use- ful in many painful chronic diseases. Internally, when taken in from 2 to 12 drops, it acts also as a stimulant. SECTION XII. — OF OIL OF MINT. This oil which is rarely met with, is prepared by distilling the leaves of the mentha crispa, along with water. It is at first pale yellow, but by keeping, deepens into yellowish-red. Its smell and taste is similar to those of mint. Its specific gravity as determined by Dr Lewis is 0*975. When cooled down sufficiently, it becomes solid. SECTION XIII OF OIL OF FENNEL. This oil is obtained from anethumfceniculum. It is colourless, or has a slight shade of yellow. Its taste and smell are similar to those of the plant, from which it is extracted. Its specific gravity, as determined by Dr Lewis, is 0*997. When cooled below 50°, it * Annalen der Pharmacie, vii. 162. orfev Its j and browi colon J smell ( and tlj Th yield \ far tlic Tht of the expres^ This h gravity! crystalf which ' Ann. OIL OF NUTMEGS. 477 t witVi I to be 1 time by the it from )y Liu- i a spe- lot, and ,uble in ich may mpioyed ; then a of 0-920 to 248°, (. What at 343°^. line witb- o yeilow. ihet*), contain- [ternally in found use- ^en in from r the leaves Bale yellow, Ud taste is Led by Dr Komes solid. Dlourless, or [e similar to Vific gravity [elow 50 crystallizes. Two kinds of crystals are formed, the one kind in large plates is heavier than water, and much less volatile than the second, which is lighter than water, and passes over first when both are distilled together. This oil was analyzed by Blanchet and Sell, and found composed of Carbon . . 76' 14 or 6^ atoms Hydrogen . . 8'49 or 4 atoms Oxygen . . 15' 4 7 or 1 atom 100-00 The stearin from this oil was composed of Carbon 79-89 or 10 atoms = 7-5 or per cent. 81-08 Hydrogen 8-17 or 6 atoms = 0*75 — — 8-11 Oxygen 11-94 or 1 atom =1-0 _ _ 10-81 it 100-00* 9-25 100 Or the same as the stearin from anise oil. The characters of the two also corresponded, showing their identity. SECTION XIV. OF OIL OF DILL. This oil is obtained from the seeds of the anethum graveolens. It has a light yellow colour. Its taste is sweetish and hot ; its smell is very penetrating. It is soluble in 1440 times its weight of water according to Teitzraann ; but dissolves readily in alcohol and water. Tietzmann says its specific gravity is 0-881; while Dr Lewis makes it as high as 0*994. SECTION XV. — OF OIL OF CHAMOMILE. This oil is extracted from the flowers of the matricorla chamomiUa, or feverfew. Its colour is deep blue. It is thick and almost opaque. Its smell is similar to tiiat of the plant from which it is obtained, and its taste aromatic. When left exposed to the air, it becomes brown and unctuous. Nitric acid dissolves it, assuming a brown colour, and water throws down from tiie solution a resin having the smell of musk. Sasse affirms, that if it be mixed with sulphuric acid and then with water, it burns with an explosion. The anthemis nohilis, arnica montana and archillea millefolium yield also blue-coloured oils. But it has not been ascertained how far they agree with the oil of chamomile in their characters. SECTION XVI OF OIL OF NUT3IEGS. There are two oils obtainable from the nutmeg, which is the fruit of the myristica moschata ; namely ?i fixed oil, wiiich is extracted by expression, and a volatile oil obtained by distillation with water. This last is a colourless or slightly yellow-coloured oil. Its specific gravity varies from 0-920 to 0-948. When kept it deposits a solid crystallized matter, which has been considered as camphor, but which sinks in water .f It dissolves readily in alcohol and ether, * Ann. (Icr I*lu«riiiacii'. vi. 289. f John has given il the natn«» of mi/risticiii. ;^ ■) 478 VOLATILE OILS. i I I I i ! f. i and crystallizes in prisms. Fuming nitric acid sots it on fire. With sulphuric acid it becomes reddish-brown, and deposits a resinous substance. SECTION XVII. OF OIL OF TANSEY. This oil is extracted from the leaves and flowers of the tanacetum vulgare, or common tansey. It is usually yellow, but is said some- times to have a green colour, when the plant has vegetated upon a fertile soil. It has the peculiar flavour of tansey, and on the conti- nent is used in medicine. SECTION XVIII. OF OIL OF ASARUM. This oil was obtained from the asarmn Europeum, by Dr Graeger. Ho sent an alcoholic solution of it to MM. Blanchet and Sell, who se])arated it from the spirits, and ascertained its characters and composition.* The oil has a yellow colour, has a glutinous consistence, is lighter than water, has a sharp burning taste, and the smell of valerian. It is but little soluble in water, but more soluble in alcohol, ether, fixed and volatile oils. Its constituents were Carbon . . 76'3C or 7 atoms Hydrogen . . 9*10 or 5 atoms Oxygen . . 14*54 or 1 atom 100-00 But no conclusion can be drawn from this analysis, because the oil contained in solution a quantity of asarin, or asarum camphor. SECTION XIX. OF OIL OF CARAWAYS. This oil is extracted from the seeds of the carum carvi, has a pale yellow colour, and the odour and taste of oi7 of cummin, extracted from the cwninum cyminum. How far these two oils agree with each other has not been ascertained. The latter is said by Dr Lewis to be specifically heavier than the former. But in colour, fluidity, taste and smell, they agree. SECTION XX. — OF OIL OF PIMENTO. This oil is extracted from the covering of the fruit of the wyrtus pimenta. It is yellowish, or almost colourless, has a smell analogous to that of cloves, an acrid taste, and a specific gravity above that of water. According to Bonastre, it combines with bases in the same way as oil of cloves ; but these compounds have not yet been examined. SECTION XXI. OF OIL OF PARSLEY. It is obtained from the apium petroselinum. Colour light yellow, has a strong odour of parsley. When agitated with water it is * Aiinalen der Pharnmcic, vi. tJOG. 1 new It hi is I- into] and has turpJ But teepj ofthi The^ Mli solve I water potasl nitric! m opaquj WJienf OIL OF SASSAFRAS. 479 With i'mous acetum some- upon a 3 conti- 5raeger. ieU, who ter3 and is lighter valerian. lol, ether, )ecau9e the jamplior. cartji, has a \n, extracted , agree with said by Dr it in colour, ijf the inyrtus [ell analogous labovethatof Is in the same lot yet been light yellow, th water it i* divided into a fluid portion, which swims on the surface of the water, and a solid portion, which falls to the bottom. This last portion may be crystallized, and has been considered as camphor. It melts at 8()°. The camphor from this oil was analyzed by MM. Blanchet and Sell. They obtained Carbon 65'53 or 6 atoms = 4*5 or per cent. ()5'46 Hydrogen (J-38 or 3 atoms = 0-375 — — 5-45 Oxygen 28-09 or 2 atoms = 2-0 — — 29-09 100-00* 6-875 100-00 Thus it differs greatly from common camphor, which is a compound of 10 atoms carbon =75 8 atoms hydrogen = 1 1 atom oxygen = 1 9-5 It contains much more oxygen, and less hydrogen. Blanchet and Sell consider it as a hydrate of oil of parsley. The fresh parsley oil was changed into the camphor, by agitation for some days in water. It was pressed between folds of blotting paper, and dissolved in alcohol. It crystallized in G-sided prisms, melted at 86°, and congealed again at 70*. It boiled at 572°, and became brown, but could not be sublimed. SECTION XXII. — OF OIL OF SASSAFRAS. This oil is obtained from the root of the laurus sassafras. When new it is colourless, but by keeping, becomes yellow or even red. It has the smell of sassafras, and a hot taste. Its specific gravity is 1-094. When agitated with water it separates, like oil of parsley, into 2 portions, a fluid oil which swims on the surface of the liquid, and a heavier oil which, though still fluid, falls to the bottom. It has been supposed that the lighter oil is nothing else than oil of turpentine, with which the oil of sassafras has been adulterated. But this is contradicted by the experiments of Bonastre.f By keeping, this oil deposits crystals, which have the smell and taste of the oil. The specific gravity of these crystals, at 43°, is 1-245. They melt at 54°i, and the specific gravity is then said to be only 1-110. These crystals are scarcely soluble in water ; but they dis- solve readily in alcohol, and the solution is not precipitated by water. They are not soluble in muriatic or acetic acid, or caustic potash, even when assisted by heat. When treated with boiling nitric acid, they yield oxalic acid.| When subjected to a current of chlorine gas, it becomes thick, opaque, and white. It scarcely combines with the caustic alkalies. When long exposed to the contact of ammonia, it becomes muddy * Poggendorf's Anriiileii, xxix. 134. f Jour, de Phannacie, xiv. 647. X Bonastrc, Jour, do Pliannacic, xiv. 579. \1 \ mm 480 VOLATILE OILS. rll 11 I' f I and thick, but no crystals are formed. When this muddy oil is kept for some time in a phial with a ground stopper, ^ds of it re- cover their original fluidity. In commerce this oil is found adulterated by a mixture of oil of lavender. The adulterated oil consists usually of 2 parts oil of sassafras, and 1 part oil of lavender. It has a yell )w colour, and when poured into water, the greatest part swims on the surface, while a certain portion sinks to the bottom. Both portions are reddened by nitric acid, a property which characterizes oil of sas- safras. Sometimes it is adulterated with oil of turpentine. If we mix such an adulterated oil with water, and distil cautiously, the oil of turpentine passes over first ; and then the oil of sassafras ; so that the two oils may in this way be completely separated. Sometimes oil of sassafras is mixed at once with oil of turpentine and oil of cloves. To separate these three oils, M. Bonastre put into a retort 300 parts of the mixture, 100 parts of caustic soda, and the requisite quantity of water, and distilled. The oil of tur- pentine was found swimming on the surface of the liquid, in the receiver, and the oil of sassafras at the bottom of that liquid. The residue in the retort being concentrated, deposited crystals, which consisted of a combination of oil of cloves and soda.* V I: I . SECTION XXIII. OF OIL OF BASIL. This cil is obtained from the ocymum basilicum. I merely men- tion it here, in order to notice a crystallized substance observed in it by M. Bonastre.f The crystals were 4-sided pyramids, with very acute faces. They were very little soluble in cold water, but very soluble in boiling water, and were again deposited when the solution cooled. They were partly soluble in cold alcohol, and the solution reddened vegetable blues. Boiling alcohol dissolves them completely, and they are deposited again when the solution cools. The crystals from the aqueous solution had scarcely any taste ; those from the alcoholic had the smell and taste of oil of basil. 6 parts of ether scarcely dissolved I part of these crystals. They were very soluble in cold nitric acid, and acetic acid. S'dphuric acid gave them a red colour. Caustic ammonia dissolved them. Water rendered the solution muddy, but no frothing was produced. SECTION XXIV. — OF OIL OF HOPS. This oil may be obtained either by distillation, or by means of alcohol, from the common hops, which are the blossoms of the hnmilus Inpilus. It has a greenish-yellow colour, and has the peculiar odour and taste which distinguishes hops. Its specific gravity is 0*910. It is converted, by keeping, into a kind of resin. When hops are digested in alcohol, a greenish-yellow solid matter is ob- tained, consisting partlv of oil and partly of resin. The older the -p partly ot oil anu p? Bonastre, Joiir. dc Fharmacie, xiv. G16. f Jour, dc PhHrniHcic, xvii. C4C. degr( oil. heatc It solves acid separi engag heatec Jt niixl soda, COllipoJ But on, OF rOTATOKS. 481 it re- oil oi cil of ir, and arface, ms are of saa- vre mi''' [le oil of , 90 tV.at irpentine istre put stic soda, ,il of tnr- id, in tlie uid. The :al3, wlucU merely tnen- ibservcd in ^cute faces, soluble in ition cooled. ,n reddened detely, and fhe crystals Ise from the ,rts of etber very soluble ave them a ■endered tbe by means of isoins of tbe Is the peculiar I tic gravity is I • When Iniatter is ob- Irbe older the Vus "vii. 640. hops, the 2 1 atom oxygen =1-0 — — 18*20 5*5 100*00 Dumas found the specific gn.vity of the vapour of this oil 3*147. Now 5 volumes ca» bon . . =2*0833 6 volumes hydrogen . . =0*4166 5 ^ volume oxygen . . = 0*5555 3*0555 Hence we see that the vapour consists of 5 volumes carbon, 6 volumes hydrogen, and half a volume of oxygen, condensed into 1 volume. DIVISION III._OF ACRID AND VESICATING OILS. The number of these oils at present known is not great. They all seem to contain sulphur as one of their constituents : whether the vesieating property be connected with this constituent, we do not know. SECTION I. — OF OIL OF MUSTARD. It has been shown by the experiments of Robiquet, Boutron- Charlard, Faure,t Hesse,t and Henry and Garot, that the vola- tile oil of mustard does not exist ready formed in the seeds of the plant, but is formed by the action of water during the distillation. It may be obtained in the same way as volatile oil of almonds. Its colour is usually brown ; but M. Eoutron- Charlard has suc- ceeded in obtaining it very nearly colourless. It is, when in that state, limpid and very fluid. Its specific gravity at 68° is 1*015. It boils at 289''^. Its smell is excessively strong and penetrat- ing. It is very solu])le in alcohol and ether, and is separated from these solutions by water. While hot it dissolves a great quantity of sul- phur, wliich separates in crystals when the solution cools. It dis- toJ alll (]uf the it fori * Ann. (le Chiin. et de Pliys. Ivi. 314 ■ * f Jour, de Piiarmacie, xxi. 4f)I. J Annalcn der Pharmacie, xiv. 41. OIL OF MUSTAItn. 483 a«rroo- ovl S-H7. 3 carbon, 6 ■nsed mto I solves likewise a good ileal of phospliorua while hot. On cooling down, the phosphorns separates in a liqnid titate till the oil eools down to 108° (the melting point of phosphorus'' below which the phosphorus separates in crystals. Chlorine acts upon this oil, and muriatic acid is formed. When alkalies are heated with it, there are produced at the same time sulphurets of the alkalies and sulphocyanodides. Nitric iicid and aqua regia act upon it with energy, and a great (quantity of sulphuric acid is formed.* The specilic gravity of its vapour, as determined by Dumas and Pelouze, is 3*40. An analysis of it by Henry and Garot has been given in the Chemistry of Inorganic Bodies (ii. 182). These gentlemen showed that it contained sulphur, carbon, hydrogen, a/ote, and oxygen. Since that time, the method of analyzing such substances has been greatly improved, and the oil has been obtained in a state of greater purity. This induced Dumas and Pelouze to analyze it again. They obtained the following results : — Sulphur .... 20'2G * Carbon .... 49-53 Hydrogen .... 5*02 Azote ..... 13-45 Oxygen .... 11*74 ilLS. great. Tbey ^ts : wbetber itucnt, we do aet, Boutron- ;\iat tbe yola- le seeds of tbe Ihe distillation, almonds, .rlard bas sue- , wben in tbat (jgo is l*0l5. and penetrat- atcdfromtbese uantity of sul- ols. Itdis- l\ CO LaTniacie, xiv .41. lOO'OOt These numbers have led Dumas and Pelouze to fix upon the following as the atomic constituents of this oil : — 2^ atoms sulphur 16 atoms carbon 10 atoms hydrogen 2 atoms azote 2^ {itoms oxygen = 5 or per cent. 20*62 = 12 — — 4<)-48 = 1-25 — — 5-16 = 3-5 — _ 14-43 = 2-5 _ _ 10-31 24-25 100-00 If we suppose these volumes to be united together, and condensed into :|;th part of their bulk, we obtain for the specific gravity of the vapour of this oil, 3-3!), a number which almost coincides with the specific gravity, as determined experimentally by Dumas and Pe- louze. T' e great quantity of oxygen and sulphur contained in this oil, togetlior with the previous experiments of Henry and Garot, natur- ally led Dumas and Pelouze to examine whether it possessed acid qualities. Kut as those bases which contain oxygen alter its nature, they were obliged to have recourse to ammonia. They found that it was absorbed rapidly by the oil, and that a new compound was formed, which was soluble in water, and capable of being crystal - • Dmuas and Pelouze ; Ann. de Cliim. et de Pliys liii. 182. f Ibid. p. 183. '■ «' ^ 484 VOLATILE OILS. 'J. , I lized. Hilt it did not possess the characters of n salt, for neithcM* acids nor hasos were capable of 8ej)aratinjr the oil from it. It was rather one of the faniily of amides, which are now hecominfr so numerous. This new substance is easily obtained : we have only to put into a phial, furnished with a » Az^ Ox^* The amide is S^* C^<^ H'" Az^ O^i + Az' ir"' which is 1 atom oil, and 2 atoms of ammonia. SECTION n. — OF OIL OF HORSE RADISH. This oil is extracted from the cochlearia armoracia, or horse radish. It has a light-yellow colour, and has the same consistency with oil of cinnamon, and is heavier than water. It has an exceeding y strong smell of horse radish, and excites tears. It is so volatile, and the smell is so strong, that a single drop of the oil is sufficient to infect a large room. Its first impression when put into the mouth, is that of sweetness ; but it speedily inflames the lips and tongue. It is slightly soluble in watc , aud comnumicates to that liquid its smell, and its ])ro])erty of ii! flaming the skin. This solution preci- pitates acetate of lead brown, and nitrate of silver black. Both these precipitates are !?ulphurets, showing that the oil contains sulphur. 6. 7. 10. 11. ii' OIL OF (JAIILU;, 4*«^ lell, i-se radish' ly wit\i oil [iceediviL y volatile, ifficient to [he mouth, kl tongue, liquid its Ition preci- JBoth these lis sulphvu'. Alcohol (lis«tolvo3 this oil readily. Wht^n loni; kej)t, it deposits hri^ >t eryatiiUiiio needles, which luive the smell, and tlie Htiniulatiii;; pi - perties of the oil. These crystals melt when heated, and subliisi** without leaving any residue.* It is hardly necessary to remark, that it is to this oil that horse radish owes its taste and its property of raising a hlister when applied to the skin. SFXTION III. — OF SrURVY-GRASS OIL. This oil is extracted from the cochlearin officinalis, or scurvy f/rass. Colour yellow, odour strong, exciting tears, taste acrid, heavier than water. Very volatile. Soluhle in alcohol, along with which it may he distilled'. The alcoholic solution is employed on the con- tinent as a medicine, under the name of spirit of cochlear ia. SECTION IV. OF OIL OF CIAIILIC. This oil is extracted from the bulbs and stem of the allium sativum, or garlic. Colour yellow, smell that of garlic, taste acrid, heavier than water. Very volatile. When applied to the skin it occasions violent pain. When burnt it emits a smell of sulphurous acid, show- ing that it contains sulphur as a constituent. It is very soluble in alcohol. t A similar oil is obtained from onions, the allium cepa of botanists. It is colourless, and contains also sulphur as a constituent. It was obtained and slightly examined by Fourcroy and Vauquelin. In this Chapter the properties of the most important volatile oils have been stated. It would be fin endless, and indeed impossible task to enumerate them all; but the following table contains a pretty copious list of plants which yield volatile oils. The part of the plant from which it is extracted, and the English name of the oil, are added in separate columns.^ Plants. Parts. oil of Colour. 1. Artemisia absynthium Leaves Wormwood Green 2. Acorus calamus Root Sweet flag Yellow 3. Myrtus pimenta Fruit Jamaica pep.§ Yellow 4. Anethum graveolens Seeds Dill Yellow 5. Angelica archangelica Root Angelica 6. Pimpinella anisum Seeds Anise White 7. lUicium anisatura Seeds Stellat. anise Brown 8. Artemisia vulgaris Leaves Mugwort 9. Citrus aurantium < 10. Melolcuca leucodendra Rind of the fruit > Bergamotte Yellow Leaves Cajeput Green 1 1 . Eugenia caryophyllata Capsules Cloves§ Yellow ♦ Einhoff; Gehlen's Jour. v. 3G5. + Cadet. % See Grcus Haiulljiu li, ii. '204. § Tlio oils luaTkeii § sink in water. r % 48() VO(.ATlI.R OII.8. M U il i ! I I ,' ( Planti. I'drtn. oil i>r Colour, 12. Curum cnrvi Seeds Caraways Yellow 13. Anioiiiuni cardainoinum Seeds Card, seeds. Yellow 14. ('arllna aeaulis Roots White 15. Scandix chaerefolinin Leaves Chervil Sulpli. yel. 16. Matricaria chainomilla Petals Chamomile Blue 17. Laurus cinnainonuui Mark (>innamon§ Yellow 18. Citrus medica ■; Rind of the fruit > Lemons Yellow 19. Cochlearia officinalis Leaves Scurvy grass Copaiba Yellow 20. Copaifera officinalis Extract White 21. Coriandruni sativum Seeds Coriand. seed White 22. Crocjis sativus Pistils Sat}Von§ Yellow 23. Piper cubeha Seeds Cubeb j)ep. Yellow 24. Laurus culilaban Bark Culilaban Ijlrown yel. 25. Cuminuni cyininuui Seeds Cuunnin Yellow 2G. Inula lielcnium Roots Elecampane White 27. Anethuin fjeniculum Seeds Fennel White 28. Croton eleutheria Bark Cyascarilla Yellow 29. Maranta galangu Roots Galanga Yellow 30. Hyssopus officinalis Leaves Hyssop Yellow 31. Juniperus communis Seeds Juniper Green 32. Lavendula spica Flowers Lavender Yellow 33. Laurus nobilis Berries Laurel Brownish 34. Prunus laurocerasus Leaves Lauroceras.§ 35. Levisticum ligusticura Roots Lovage Yellow 36. Myristica moschata Seeds* Mace Yellow 37. Origanum majorana Leaves Majorum Yellow 38. Pistacia lentiscus Resin Mastich Yellow 39. Matricaria parthcnium Plant Motherwort Blue 40. Melis3a officinalis Leaves Balm White 4 1 . Mentlia crispa Leaves White 42. piperitis Leaves Peppermint Yellow Blue and green Orange 43. Achillea millefolium Flowers Millefoil 5 Neroli 44. Citrus aurantiura Petals 45. Origanum creticum Flowers Spanish hop Brown 46. A])ium petroselinum Roots Parsley Yellow . . . C 47. Pinussylvestrisetabies < Wood & resin. > Turpentine Colourless 48. Piper nigrum Seeds Pepper Yellow 49. Rosmarinus )fficinalis Plant Rosemary Colourless 50. Mentha p'l' fjium Flowers Pennyroyal Yellow 51. Genista canariensis Root Rhodium Yellow 52. Rosa centifolia Petals Roses Colourless 53. Ruta graveolens 1 Leaves ! Rue Yellow ^ Tlie oil? maiknl <>'» sink in w;Uor. * 'I'liov violii iil.-(i a fixed oil. COtlll COMMON CAMPHOH. 487 ilouf. low How lite \ite jUow sllow own yel. ellow liltc bite eUow 'cUow 'ellow Jroen fellow {rownisb fellow ellow ellow fellow iluc A bite ^Vbite 'ellow 5lue and green lOrange llirown JYellow IColourless Yellow 1 Colourless 1 Yellow Yellow Colourless Yellow fixed oil. nmti. I'arii. Otluf Colnur. 54. JuniueruH sabiiia Leaves Sttvino Yellow 55. Salvia officinalis Leaves Sago Green 5(1. Santaliun album Wood Santaluin§ Yellow 57. Laurus sasaatVas Root Sassafras Yellow fiH. Satureia hortensls Leaves Satureia Yellow 59. TliyinuB serpilluni j Leaves & Hower > Tbyme Yellow 60. Valeriana officinalis Root Valerian Green 61. Kuiinpferia rotunda Root Zedoary < Ginger (ireenisb blue G2. Aniomum Zin/ibcr Root Yellow 63. Andropogon scha^nan- ^ thum 3 Sira Brown Several of the gum reusing, as myrrh and galhanmn, yield likewise an essential oil, and likewise the balsams, as benzoin, &c. DIVISION IV.— OF CAMPHORS. The term camphor has be n applied by apothecaries to various solid bodies which occasionally appear in volatile oils. They are distinguished by their great volatility, by a strong and [x'culiar smell, by the property of melting when heated, and burning brilliantly when held to a lighted candle. By far the most important of these bodies is the well known substance constituting common camphor, SECTION I. — OF COMMON CAMPHOH. Camphor was unknown to the Greeks and Romans ; but appears to have been introduced into medicine by the Arabian physicians, and to have been distinguished by the name of kamphur. Hence the Greek and Latin word camphora, and our English word cam- phor. iEtius is the first person who notices it. He was physician in the Court of Constantinoi)le, about the middle of the 6th century, and his writings were much admired and studied during the 15th and 16th centuries. Paracelsus mentions it repeatedly in his writ- ings, and from the way in whicii he speaks of it, one would suppose that it must have been in connnon use in his time.* Yet 1 cannot find any allusion to it in the Praxis Chymeatrica of Joannes Hartmannus, printed at Geneva in 1647. There is an account of its medical uses in the Pharmacopee Royale of Charas, printed at Paris in 1676 (p. 704). Van Helmont notices its solubility in nitric acid, and says that it may be thrown down unaltered by water.f The first person who examined its properties in detail was Neumann, in his (J The oils marked (J sink in water. * Thus, in his treatise De Caducis, he classes it with mumia, spodium, and other cuinmuii medicines of the time. Opera Piiraceisi, i. 073 (Geneva edition, of 1 058). t De litliiasi, p. 24. UBBBMBI 488 VOLATII-E OILS. I'' ! ! V: ') well known dissertation on it, published in 1725.* He account of its chemical character? :.:. .1 shows that it differs from oils, resins, and gums, and that it is entitled to rank as a peculiar vegeta- ble principle. He mentions in this paper, that he had obtained from oil of thyme a crystallized substance, possessed of all the characters of camphor, except the colour. It comes to Europe chiefly from Japan. It is obtained from the laurus camphora, a tree common in the East, by distilling the wood along with water in large iron pots, on which are fitted earthen heads stuffed with straw. The cami)hor sublimes, and concretes upon the straw in the form of a grey powder.f It is afterwards refined in Europe by a second sublimation. The vessels are of glass, and somewhat of the shape of a turnip, with a small mouth above loosely covered with paper. According to Ferber, about \th of pounded chalk is mixed with the crude camphor^ ; but others assure us that there is no addition whatever employed. According to Lewis, nothing more is necessary than a proper regulation of the firc§ ; and Professor llobison, who witnessed the process as well as Neu- mann, informs us, that the camphor in the subliming vessel is in a liquid state, which it could scarcely be if quick-lime were employed, at least in any considerable quantity. || The quantity of quick-lime used is said, by Berzclius, to amount to y jth of the camphor. It is necessary to keep the upper part of the subliming vessel only a very little below the temperature at which camphor melts. This causes the camphor to concrete into a cake. Camphor is a white brittle substance, having a peculiar aromatic odour, and a strong hot acrid taste. Its specific gravity is 0*9887.^ It melts at the temperature of 288°, and boils when heated to 400°, according to my experiments.** It is not altered by atmospheric air ; but it is so volatile, that if it be exposed during warm weather in an open vessel, it evaporates completely. When slowly sublimed, or when a hot alcoholic saturated solution is allowed to cool, it crystallizes in octahedrons, or in six-sided plates and pyraniids.ft It is insoluble in water ; but it communicates to that liquid a certain portion of its peculiar odour4+ «|i • Phil. Traiie. vol. xxxiii. j). :i2\. f Neumann's Chem. p. 319. J Gron's Handbuch, ii. 219, (5 Noiirnann. ibid. II Black's Lccturosjii. .')51 . Sue Gay-Lussao, Ann. do Cliini. ct de Pliys. viii. 7.5. II Accordin-^ to Brisson. Dr Shaw states it at 0'9D() (Shaw's Boyle, ii. 340); and this lias been copied into most of the recent chemical books. Probably it varies in its density considerably. ** Gay-Liissac says, that it melts at 349°, and boils at .399*^ (Ann. do Chini. et do Phys. viii. 78). This statement docs not agree with my experience ou the subject. f f Romien. tX Prom (he experiments of Cadet, it appears that a French pint of water liis- solvcs ai)ont Hi grains of rani|)hor, and (I'.iit the eiuiqihor may be preei|iitiited by pure poia>li. Ann. dc <'liiiii. ixii. 1 ;)■_'. COMMON CAMPHOR. 489 lives an ■om oils, vegcta- led from laracters from the he wood icn heads upon the efined in lass, and 'e loosely pounded •e us that Lewis, the tire§ ; 1 as Neu- el is in a employed, to amount )er part of •e at which to a cake, r aromatic p 0-9887.T heated to tile, that if evaporates Dcd solution n six-sided lat liquid a 1. r 319. Phys. viii. "5. ioylc, ii. 34(i); Probably it n. dc Chini. ot, crieiice on the it of water dis- pvpcipitnti'd l)y It dissolves readily in alcohol, and is precipitated again by water. According to Neumann, well rectified alcohol dissolves fjths of its weight of camphor. By distillation the alcohol })asses over tirst and leaves the camphor. This property atlbrds an easy method of purify- ing camphor. Dissolve the camphor in alcohol, distil ofl' the spirit, and melt the camphor into a cake in a glass vessel.* If the alco- holic solution of camphor be diluted with water as nmch as possible, without causing the camphor to i)recipitate, small crystals of camphor resembling feathers gradually i'orm.f Camphor is soluble also in oils, both fixed and volatile. If the solution be made by means of heat, as it cools part of the camphor precipitates, and assumes the form of plumose or feather-like crystals.^ It dissolves in bisulphuret of carbon, and the solution may be mixed with alcohol but not with water.§ Camphor is not acted on by alkalies, either pure or in the state of carbonates. Pure alkalies indeed seem to dissolve a little cam- phor ; but the quantity is too small to be perceptible by any other quality than its odour. || Neither is it acted on by any of the neutral salts which have hitherto been tried. Acids dissolve camphor without effervescence, and in general it may be precipitated unaltered from the recent solution. To Mr Hatchett we arc indebted for an accurate investigation of the action of sulphuric acid on camphor. Upon 100 grains of powdered camphor he poured 1 ounce of sulphuric acid. The camphor immediately became yellow, and gradually dissolved while the acid changed, first to brownish-red, and afterwards to brown. In about an hour the liquid became blackish-brown, and began to emit abundance of sulphurous acid gas. In four hours the whole appeared like a thick black liquid, and no other smell except that of sulphurous acid could be distinguished in it. As, during two days, no farther alteration took place, the alembic con- taining the solution wa"> put upon a sand-bath moderately warm, by which means an additional quantity of sulphurous acid gas was driven oflt". After two days the liquid was slowly mixed with 6 ounces of water. It became reddish-brown, a considerable coagulum of the same colour subsided, the sulphurous acid smell became im- perceptible, and was succeeded by a smell similar to that of a mix- ture of the oils of lavender and pe])pormint. The whole was now slowly distilled. The water which came over had the same smell as the original liquid, and there floated over it a little yellowish oil. A blackish-brown mass remained behind, not acted on l)y water ; but alcohol extracted a resinous substance, and acquired a blackish-brown colour. What remained was charcoal. Thus, by the action of sulphuric acid, the cau)phor was decomposed and con- * This proces?, proposed by Lewis (Ncuinanu's Cheni. p. 3'20). is surely pre- ferable to that of Troiiunsdorf, who precipitates the camphor by water from the alcohol, and then melts it into a cake. See Gren's Mandbiich, ii. 'i-0. t Koniien, Mem. Par. 1756, p 41. % llomicu. ibid. () Liuiipiivliiis. Houilloi) la Cir.mur', Aim ('him. xxiii. \^)4. 490 VOLATILE OILS. verted into oil, blackish-brown resin, and charcoal. The proportion of each was as follows : — Yellow oil . . . . 3 grains Charcoal .... 53 Resinous substance . . 4 J >, : h i! n 105 Making an increase of 5 grains, either from water, which was re- tained by the resinous-like substance, or from oxygen with which it had combined. This resinous-like substance, thus obtained, was in reality a species of artificial tannin. It was very brittle, had the odour of carorael, and an astringent taste. It dissolved in cold water, and the solution precipitated iron, lead, tin, and lime, dark brown. It precipitated gold in the metallic state, threw down isinglass in the state of a blackish insoluble substance, and had the property of converting skin into leather. A small quantity of nitric acid con- verted it into the artificial tannin obtained from charcoal by nitric acid.* From the farther researches of Chevreul on this subject, it ap- pears that when sulphuric acid is distilled ofl" camphor, there is formed, 1 . A volatile oil which has the odour of camphor : 2. A charry matter, which is a combination of sulphuric acid and a hydro- guretted charcoal : 3. An astringent substance, which is likewise a compound of sulphuric acid, and a charcoal still more hydroguretted than the preceding. The charry residuum is not sensibly soluble in water. When distilled it gives sulphurous acid, carbonic acid, and leaves a residue, which is a compound of carbon and sulphur .f Nitric acid dissolves camphor readily, and in great abundance. The solution separates into two portions ; that which contains the camphor, and most of the acid, floats upon the top of the other in the form of a very pale yellow oil. Thi solution is known by the name of oil of camphor. Water and several metals precipitate the camphor unaltered.^ Alcohol combines with the oil of camphor. When this solution of camphor in nitric acid is long kept, a portion of the camphor separates in crystals, and swims on the surface, and a small portion is converted into camphoric acid.§ Muriatic, sulphurous, and fluoric acids, in the state of gas, dis- solve camphor. When water is added, the camphor appears, unaltered, in flakes which swim on the surface of the water. || It is dissolved also by water impregnated with carbonic acid gas,^[ by acetic acid,** and probably by all acids. It absorbs, according to the experiments of Saussure, 144 times * Hatclu'tl's additional Experiments on Artificial Tannin, Phil. Trans. 1805. t Ann. de Chim. Ixxiii. 167. } Neumann's Chemistry, p. 321, § Planehe found these chan<,'e9 in a phial of oil of camphor, wliich had been kept unopened for 14 years. Ann. de Chim. xliii. 340. II Fourcroy. \ .Tour, de Piiys. lii. 67. *» Phil. Mil:. XV 15(>. Aronuuic viurfjar consists chielly of this conipoinid. •portion was re- which it reality a odour of iter, and own. It ss in the iperty of icid con- by nitric ct, it a]p- , there is or: 2. A 1 a hydro- likewise a •oguretted >ly soluble iDiiic acid, sulphur.t bundance. intains the e other in »wn by the ipitate the ■ camphor. a portion irface, and of gas, dis- appears, ;er.|l It is gas,t i>y 144 times rans. 1805. |). 321. had been kept is coiiipounii. COMMON CAMPHOR. 491 its volume of muriatic acid gas, and assumes the form of a' colour- less liquid-like water, which speedily congeals in the air, the watery vapour which is absorbed by the acid separating it from the camphor. When heat is applied to camphor it is volatilized. It catches fire very readily, and emits a great deal of flame as it burns, but it leaves no residuum. It is so inflammable that it continues to burn even on the surface of water. When camphor is set on fire in a large glass globe filled with oxygen gas, and containing a little water, it burns with a very bright flame, and produces a great deal of heat. The inner surface of the glass is soon covered with a black powder, which has all the properties of charcoal ; a quantity of carbonic acid gas is evolved ; the water in the globe acquires a strong smell, and is impregnated with carbonic acid and camphoric acid.* If 2 parts of alumina and 1 of camphor be formed into a paste with water, and distilled in a glass retort, there comes over into the receiver (which should contain a little water, and communicate with a pneumatic apparatus) a volatile oil of a golden-yellow colour, a little camphoric acid, which dissolves in the water, and a quantity of carbonic acid gas and carburetted hydrogen gas, which may be collected by means of a pneumatic apparatus. There remains in the retort a substance of a deep black colour, composed of alumina and charcoal. By this process, from 122*284 parts of camphor, M. Bouillon la Grange, to whom we are indebted for the whole of the analysis of camphor, obtained 45'856 parts of volatile oil, and 30*571 parts of charcoal. The proportion of the other products was not ascertained.! Bouillon la Grange showed that the constituents of camphor are carbon and hydrogen. I made an ultimate analysis of it by means of oxide of copper, from which it appeared that oxygen also enters into it as a constituent. It was afterwards analyzed by Saussure and GtibeLJ But a more accurate analysis was made by Liebig, in 1831.§ It is obvious, from his own statements, that the result is not perfectly exact ; but the volatility of the camphor renders the experiment very difficult of performance. He obtained Carbon 81*763 or 12 atoms = 9 or per cent. 80*89 Hydrogen 9*702 or 9 atoms = 1*125 — — 10*12 Oxygen 8*535 or 1 atom =1 — — 8*99 100*000 11*125 100 But camphor has been still more lately analyzed by Dumas. || He obtained Carbon 78*02 or 10 atoms = 7*5 or per cent. 78*94 Hydrogen 10*39 or 8 atoms =1 — — 10*53 Oyxgen 11*59 or 1 atom =1 — — 10*53 100*00 9*5 * Bouillon la Graiiire. Ann. de Cliiin. xxiii. 1G8. X Si'liweiiT^ev's Juiir. x!. .S.Vi. § Ann. lie ("hi II. ot de V\\\<. \lvii, 9.'). 100*00 t Ibid. 157. ll.id. 'Hi i! ! 6l '■ 492 VOLATILK aiLS. J i Duniaa found the specific gravity of the vapour of camphor 5"468. Now, 10 volumes carhon . . = 4*16(](i 8 volumes hydrogen . = 0*5555 ^ volume oxygen . . = •0*5555 5-2777 So that camphor vapour consists of 10 volumes carbon, 8 volumes hydrogen, and {; volume oxygen condensed into 1 volume. The analysis of camphor by Blanchet and Sell in 1833, agrees very nearly with that of Dumas. They obtained Carbon 77-96 Hydrogen . . . . 10-Gl Oxygen .... 11-43 100-00* Camphrone. This substance was discovered by M. Fremy, in 1835.f He obtained it in the following way : — A quantity of lime was put into a porcelain tube, which was heated red hot. When the requisite temperature was obtained, fragments of camphor were introduced, which made its way through the lime, and there was obtained a liquid, to which Fremy has given the name of camphrone. It is a liquid slightly coloured, has a strong and characteristic odour, quite different from that of camphor. By a single distillation it gives a light oil, soluble in alcohol and ether, but insoluble in water. It boils at 167°. It was analyzed by M. Fremy, who obtained Carbon 85-03 or 24 atoms =18 or per cent. 85-21 Hydrogen 10-21 or 17 atoms = 2-125 — — 10-06 Oxygen 4-76 or 1 atom =1 — — 4-73 100-00 100-00 21-125 Now, camphor is C'^ H'' O'. Consequently 2 atoms of camphor . C^* H»« O" 1 atom of camphrone . C^** H'^ O It is, therefore, 2 atoms of camphor, deprived of i atom of water. M. Fremy found the complete combustion of camphrone attended with considerable difficulty. It sometimes contains camphor. To be certain of its purity wc take care that its boiling point is 167°; or that, when evaporated upon a slip of glass it does not leave any trace of camphor. Dumas subjected the camphor from oil of lavender to a chemical analysis, and found its composition exactly the same as that of connnon camphor. He distinguishes by the name of camphogene, what he considers as the basis of camphor. It is a volatile oil composed of 10 atoms cam I Thud It consi becor * Ann. 'lor IMuuiir.iclo. vi. 004. f Ann. (Ic CliiiTi. el i!c I'livs. li.\. Ki. 5-468. volumes ,, agrees 'remv, m as heated •raginents the lime, the name racteristic listillation soluble in 85-21 10-06 4-73 100-00 of water, le attended phor. To int is 167°; t leave any a chemical as that of e considers f 10 atoms 3 CAMl'HOK FROM OIL OF ANISE. 493 carbon and 8 atoms hydrogen. It may be extracted pure from the artiiicial caihphor formed, by uniting oil of turpentine and muriatic acid. Camphor consists of an integrant particle of camphogene united to an jitom of oxygen. Common camphor, obtained by distillation from the /aMn«cawj/?/ or 2 atoms = 2 IOChToO 8 •(525 or per cent Gi)'57 7-24 23-19 It will be seen, in a preceding Section, that the volatile oil of asarum was found by Hlanchet and Sell composed of Carbon .... 7G'."G Hydrogen . . . . 9- 10 Oxygen .... 14*54 ioo"~ Blanchct and Sell consider the true formula for the oil to be or per cent. 80*00 — — G-GG — — 13*34 100-00 8 atoms carbon = G 4 atoms hydrogen = 0*5 1 atom oxygen = 1 7-5 Thus making the asarin a hydrate of the oil. The reason of the want of agreement with this formula in the analysis of the volatile oil, was the quantity of asarin which it held in solution, which of course sunk the carbon, and raised the hydrogen and oxygen somewhat too high. Leopold Gmelin has collected all the facts scattered through chemical books respecting the camphors obtained from different volatile oils.* He has enumerated no fewer than 32 species. But several of these, naphthalin for example, certainly cannot be con- sidered as camphor. I think it useless to insert this catalogue here, till tha nature of the various substances, at present called camphor, has been determined by accurate experiments. The volatile oils are so numerous, that it would be improper to introduce an account of the whole of them here, even if it were possible. M. Baybaut, a perfumer in Paris, has given a tcble of no fewer than 207 volatile oils prepared by himself, with the names of the plants from which they were obtained, the quantity from a given weight of the plant, and the nature of the oil. To this table, in the Journal de Pharmacie, vol. xx., p. 444, we refer such readers as wish for further information on this curious subject. The most productive of the 207 substances was the seeds of cummin, 100 lbs. of which yielded 2*75 lbs. of volatile oil. APPENDIX. The following substances, connected with volatile oils, are inserted here, to draw tlio attention of chemists to their investigation : — * Il'.inJbucli del' thcoretisclicn Clioniio, ii, 403. Third Edition. lS-29. 2 K I ■j I i T 498 VOLATILE OILS. ii' ^\i ii. :^i. i In < M SECTION I. — OF IIELENIN. This substance, which exists in the root of the inula helenium, or elecampane, was first noticed by M. Oeoffroy, Jun.* It was after- wards examined more in detail by I)r Lewis.f I am not aware that it has been examined by modern chemists. When the roof of elecampane is distilled, the helenin passes with the water under the form of a yellowish oil, which falls to the bottom of the water, and becomes solid. If we digest the root of elt 'am- panc in hot alcohol, and set the liquid aside, the helenin is gradually deposited in crystals. It may be purified liy distilling it a second time along with water. The crystals are colourless, and either rectangular prisms or cubes. When sublimed, it is in soft plates, which may be cut with a knife. It is heavier than water. Its taste and smell are similar to those of elecampane root. At 107°^, it melts into an oil, and when the temperature is raised, may be sublimed without alteration. It is very little soluble in water, whether cold or hot ; but very soluble in hot alcohol, but partly falls down in crystals when the liquid cools, and is totally precipitated by water. It is very soluble in ether, and in oil of turpentine. Nitric acid converts it into a resin. SECTION II. — OF BETULIN. This substance, which exists in the epidermis of the betula alba, or common birch, was discovered by Lowitz, who published an ac- count of its properties in 1788,| and it has not been since that time made a subject of investigation by modern chemists. We may obtain it under the form of white lanuginous vegetations when we heat the bark of the birch in the open air till it becomes brown. It is so bulky and light, that 8 or 10 grains of it occujjy as much room as a pound of water. When thrown on hot coals it sublimes, giving out an agreeable smell. But when we attempt to distil it in a retort, it is decomposed. When held to a lighted candle, it burns with a white flame. It is insoluble in water ; but it dissolves in 120 times its weight of cold, and 80 times its weight of boiling alcohol. When the alco- hol cools it is deposited in capillary crystals. It is soluble in ether, and in the fixed and volatile oils. Sulphuric acid dissolves it; and, when the solution is mixed with water, it concretes and becomes white. Neither the alkaline hydrates nor carbonates dissolve it. SECTION III. — OF NICOTIANIN. This concrete oily substance exists in tobacco, and gives it its characteristic odour. It was first obtained by Hermbstadt. Posselt and Reinmann prepare it in the following way : — Distil a mixture of 6 pounds of tobacco leaves, and 12 pounds of water, till one half of the liquid has passed over. Add to the liquor * Mera.de I'Acad. Paris, 1721, p. 15.5. f Lewis's Neumann's Chemistr}', p. 420. t Crell's Chemische Annulon, 1788, ii, ols?. urn, or i after- re that les with bottom elt 'am- ■adually second isms or I with a miUir to 11(1 when on. jut very hen the oluble in a resin. ula albtty ;(1 an ac- ;hat time nretations becomes )ccupy as t coals it tempt to lighted ts weight the alco- in ether, s it; and, becomes iolve it. ives it its ;. Posselt pounds of the liquor istry, p. 420. ANEMONIN. 409 fi pounds of water, and distil a second time. Repeat this a third time. On the surface of the licjuid which has distilled over, about 1 1 grains of a fatty substance swims. This is the nirotinnin. It has the smell of tobac;'o smoke, and an aromatic and bitterish taste. Heat vglatilizcs it. It is insoluble in water, but dissolves readily in alcohol and etiier. It is insolulde in the dilute acids, but soluble in caustic potash.* It was obtained also by (). Henry, and Houtron-f!harlard, but not particularly examincd.f SECTION IV. — OF ANKMONIN. This substance was discovered by M. llobert, and by Vauqnorm,t in 1820, when the fresh leaves of the anemone prntensis were distilled with 2^ times their weight of water, and the distillati(m was stopped when |ths of the water had come over. The anetmme jmlsntilla and nemorosa yields it also when treated in the same way.§ The liquid thus obtained is put into a retort, and ^th of it is again distilled ott". If this last liquid be set aside for some weeks in a cool place, it de- posits crystals of anemonin. It crystallizes in six-sided needles. It is heavier than water, and easily reduced to powder. When thrown upon a hot metallic plate, it is volatilized without leaving any residue, emitting at the same time acrid vapours. When distilled it ] asses over in the form of an oily liquid, which soon becomes solid. A small portion of it is decomposed. The smell of its vapour occasions tears, and excites a painful sensa- tion in the nostril. At the ordinary temperature of the air it has no smell, and while solid is nearly insij)id. But when in a state of fusion it is caustic, and dejirivos the tongue of sensibility for several days. It is scarcely soluble in cold water. Boiling water dissolves it, and lets it fall in crystals as the solution cools. Alcohol acts like water. The fixed and volatile oils dissolve it when assisted by heat. The strong acids, and the alkaline hydrates and carbonates decompose it. According to Schwartz, anemonin, es])ecially that from the ane- mone nemorosa, is mixed with a precipitate, not capable of crystal- lizing, which is produced by the action of the air on the substances distilled over. This precipitate is a light bulky powder, not vola- tile, scarcely soluble in water, and insoluble in alcohol and the dilute acids. The alkalies give it a yellow colour, and decompose it into two substances, one of which dissolves in the alkaline liquid, while the other forms with the alkali an insoluble compound. The first of these substances may be precipitated by an acid from its alkaline solution. Schwartz conceives th.it this powder is com- posed of two acids : one, volatile and soluble in boiling water, he calls anemonic acid ; to the other, which is yellow and insoluble, he has given no name. Anemonin possesses poisonous qualities, and irritates and inflames the skin. * Mag. Pliarni. xxiv. 138, and xxv. 2, o7. f .Toiir. de Pliarmacio, xxii. (107. \ Jour, dc IMiarmucic, \i. 1129. ^ Schwartz, Mag. I'harin. .\. 193, and xix. 108. ^^r 60(1 RF.NINN. C'lIAPTKR IX. O F U E S I N S. M ! The form resin (rcsinn, ^n'rnri) wn« Mpplicd by tlio ancients to cor- taiu inspissated juices, from tlie tribe ot' j)iue9, which were enipKiyi'il in medicine. Several of them are mentioned by Dioscorides and Pllnv, together with the trees from whicii thoy exude. They drew but little of the attention of chemists, till about the end of the 17th and bejrinninjT of the iHth century. Hoyle mentions couuiion rosin; but without any description of its cpialities or essential characters. Nor do we find any attempt to s])ecify these characteristic proper- ties in the chemical writinjis of Lemery, or Staid, or lioerhaavc Neumann, in his chemical, lectures ^ives a definition of resins, nearly the same as is found in modern chemical works. Of the various investigators of the nature of these bodies, which have appeared in our days, Unverdorben may be mentioned as the person to whom we are indebted for the most elaborate and valuable researches.* As resuis are found in almost all plants, and in almost every part of the jdant, it would be an impossible task to undertake to enu- merate them all. We must confine ourselves to those which exist in considerable (juantity, and which have been ap])lied to purposes of utility. They jire obtained either by exudation from trees, or by digesting the substances containing the resin in alcohol. In the first case, they cither exude from natural openings, or artificial incisions made througb the bark and part of the wood of the tree that yields them . They flow out during summer, in a liquid state, the resin being held in solution by a volatile oil, which, when the exudation is exposed to the air, either makes its escape, or is converted into rosin by the absorption of oxygen. When this change takes place, the li(iuid is converted into a solid resin. In the second case, the alcoholic solution being diluted with water, the resin falls down, and the alcohol is recovered by distilling th(! diluted licpnd. The reader can be at no loss to t'orm a notion of what is meant by resin, when he is informed that common rosin furnishes a very perfect example of a resin, and that it is from this substance that tlie whole genus derived its natne : for rosin is merely tlie word resin, altered by common use. Resins may be distinguished by the following properties : — They are solid substances, naturally brittle ; liavc a certain degree of transparency, and a colour most commonly inclining to yellow. Their taste is insipid, and they lif;ve no smell, except when they retain a portion of volatile oil, in which case they partake of the smell and acrid taste of that oil. * Poffsrenilorf's Annalen, vii. 311- 179, 487— xxi. 17-2. -xi. Q7, 230, 393— xiv. IIG— xvi. 369— xvli. ItESINS. 501 s to cor- (luployeil idos and loy drew the 17tli r)n roHUi ; araetors. • propor- )erlmavL IS, nearly i» various )earcd in to whom ■chcs.* very part ! to enu- h exist in rposes of es, or by I the first incisions his them, eing held tposed to n by the i([uid is alcoholic and the le reader !8W, when example lie genus tercd by 1 : — certain lining to ept when artakc of 369— xvli. They are non-conductori< of ehuitricity, iind when excited by fric- tion their elec^tricity i.s nciiMtivf. 'i'hey are heavier tlian water ; but the? specilic gravity varies con- 8ideral)ly even in tin; saiiu? resin iit dill'iTeiit times. '1 he following table exhibits a view of the specitie gravity of fuch of the resins aa have been hydrostatically exuiiiined :- Jalap resin 1-Olt Klemi I -0182 Anime 10284 Iligiigate resin l-()4<;| Heii/oin i'0(i:i to 1-0U2 Copal l-0(>!)t Tacamaluu! i-()4(;;i Rosin 1-()80| Mastich 1-0742 Sandarich l-0«)Ot Danunura 1-01)7 to 1-123 Lac 1-1390 Dragon's blood 1-1 9() Labdanum 1-18()2 (iuaiacum l-228<)§ When exposed to heat they melt ; and if the heat be increased they take tire, and burn with a strong yellow flame, emitting at the same time a vast (piantity of smoke. They are all insoluble in water whether cold or hot ; but when they are melted along with water, or mixed with volatile oil, and then distilled with water, they seem to unite with a portion of that licpiid ; for they become opaque;, and lose nmch of their brittleness. This at least is the case with common rosin. Tilt" are all, with a few exceptions, soluble in alcohol, especially when assisted by heat. The solution is usually trxmsparent ; and when the alcohol is evaporated, the resin is obtained unaltered in its properties. Alcohol, a<'cording to Tingry, never takes up more than ^d of its weight of resin. When the solution is mixed with water, it becomes milky, and the resin falls in a state of a white powder. They are soluble also in sulphuric ether. Several of them are soluble in fixed oils, especially in the drying oils. The greater number are solul)le in the volatile oils ; at least in oil of turpentine, the one commonly employed. Mr Ilatchett first examin.'d the action of fixed alkalies on resins, and showed that alkaline leys dissolve them with facility. He reduced a quantity of conn ion rosin to powder, and gradually adding it to a boiling lixivium of carbonate of potash, a perfect solution was obtained of a clcir yellow colour, which continued permanent after * The specific Kravitios in the text were ascertained chiefly by Brisson and by myself. The older writers dirt'cr so much from each other, that tiiere is reason to suspect that the substances tried were not always those to which we at jjresent give the same names. f Unvcrdorben. | By my trials. § Brande. I.! 502 hesins. long exposure to the air. The experiment succeeded equally with carbonate of soda, and with solutions of pure potash or soda. Every other resin tried was dissolved as well as rosin. The well-known fact that the soap-makers in this country constantly mix rosin with their soap ; that it owes its yellow colour, its odour, and its easy solubility in water to this addition, ought to have led chemists to have suspected the solubility of resins in alkalies. No such conse- quence, however, was drawn from this notorious fact. These alkaline solutions of resins have the properties of soap, and may be employed as detergents. When mixed with an acid, the resin is separated in flakes, usually of a yellow colour, and not much altered in its nature. From the experiments of Unverdorben, it is evident that several of the resins have the properties of acids. Ammonia acts but imperfectly upon resins, and does not form a complete solution of most of them. But Unverdorben has shown that ammoniacal gas is absorbed by resins, and a neutral compound formed. It was the received opinion of chemists that acids do not act upon resins. This opinion seems to have been founded on the known effect of nitric acid upon oils, and on the old theory derived from that action, that resins are compounds of an oil and an acid.* Mr Hatchett first ascertained this opinion also to be erroneous, and showed that most of the acids dissolve resins with facility, produc- ing different phenomena according to circumstances. When sulphuric acid is poured upon any of the resins in powder it dissolves them in a few minu;.es. At first the solution is trans- parent, of a yellowish-brown colour, and of the consistency of a viscid oil, and the resin may be precipitated nearly unaltered by the addi- tion of water. If the solution be placed on a sand bath, its colour becomes deeper, sulphurous acid gas is emitted, and it becomes very ■ thick, and of an intense black.f If the solution, some time after it is completed, and before it has acquired the deep black colour, be edulcorated, and the residuum digested in alcohol, and the alcohol afterwards separated by distillation, the residue is in part soluble in cold water, and the portion dissolved possesses the properties of artificial tannin.$ Thus it appears, that sulphuric acid dissolves resins, but gradually acts upon them after the solution is completed, converting them first into artificial tannin, and afterwards reducing them to charcoal ; for the last black state of the solution is owing to the evolution of this substance. The charcoal thus formed is dense, and burns rather like mineral than vegetable coal. Its quantity is also very considerable. The following table exhibits a view of the proportion of charcoal obtained by Mr Hatchett, by digesting different resins in sulphuric acid, edulcorating the residue, and separating the tannin by means of alcohol and water.§ The quantity of resin employed was always 100 grains. ' See Hoffmann, Observ. Phys, Chim. Select, p. 55. f Hatchett on an Artificial Tanning Substance, Phil. Trans. X Hatchett's Third Series of Experiments, ibid, 1800. § Hatchett, ibid. 1805. HESINS. Copal 67 Mastich (H) Elemi 63 Tacamahac 62 Amber 56 Rosin 43 503 The quantity of charcoal formed by this process is very remarka- ble. TLe same substances, when charred in the usual way by expo- sure to a red heat in close vessels, yield very little charcoal. The following table exhibits the quantity obtained by Mr Hatchett from 1 00 grains of several of them : — * Mastich . . . 4*50 grains. Amber . . . 3*50 Rosin .... 0*65 Nitric acid likewise dissolves the resins with facility, but not with- out changing their nature. Mr Hatchett was first led to examine the action of this acid on resins, by observing that resins are thrown down by acids from their solutions in alkalies in the state of a curdy precipitate ; but when nitric acid is added in excess, the whole of *he preci])itate is redissolved in a boiling heat. This remarkable fact, which did not hold when sulphuric or muriatic acids were used, led him to try whether the resins were soluble in nitric acid. He poured nitric acid of the specific gravity 1'38, on powdered rosin in a tubulated retort ; and by repeated distillation formed a complete solution of a brownish-yellow colour. The solution took place much sooner in an open matrass than in close vessels. The solution con- tinues permanent, though left exposed to the air. It becomes turbid when water is added ; but when the mixture is boiled, the whole is redissolved. When Mr Hatchett collected the precipitate thrown down by water by filtration, he found that it still possessed several of the properties of resin. The resin is thrown down from nitric acid by potash, soda, and ammonia ; but an excess of these alkalies redissolves the precipitate, and forms brownish orange-coloured liquids. When Mr Hatchett dissolved resin in boiling nitric acid, the solution was attended with a copious discharge of nitrous gas ; and when the powdered resin was thrown into cold nitric acid, a considerable efi'ervescence soon took place, and a porous mass was formed, commonly of a deep orange colour. When the digestion of nitric acid upon a resinous substance is con- tinued long enough, and the quantity of acid is sufficient, the dis- solved resin is completely changed ; it is not precipitated by water ; and by evaporation a viscid substance of a deep-yellow colour is obtained, equally soluble in water and alcohol, and seemingly inter- mediate between resin and extractive.! If the abstraction of nitric acid be repeated, this substance gradually assumes the properties of artificial tannin4 Thus it appears that nitric acid gradually alters * Hatchett's Third Series of Experiments, Phil Trans. I80C. t Hatchett on an Artificial Tanning Substance, Phil. Trans. 1803. t. Hatchett's Additionai Experiments on Artificial Tannin, Phil. Trans. iSOj. 504 IlESINS. ■i i 1 the nature of resin, producing a suite of changes which terminate in artificial tannin, upon which nitric acid has no action. Muriatic acid and acetic acid dissolve resin slowly, and it may be precipitated again from them unaltered. Mr Hatchett, to whom we are indebted for the knowledge of all these solutions, recommends acetic acid as an excellent solvent of resins for vegetable analyses. He employed it himself with much address in his analysis of the dif- ferent varieties of lac* When resins are subjected to destructive distillation, we obtain, according to Gren, carburetted hydrogen and carbonic acid gas, a very small portion of acidulous water, and much empyreuraatic oil. The charcoal is light and brilliant, and contains no alkali.f When volatile oils are exposed for some time to the action of the atmosphere, they acquire consistency, and assume the properties of resins. During this change they absorb a quantity of oxygen from the air. Westrumb put 30 grains of oil of turpentine into 40 cubic inches of chlorine gas. Heat was evolved ; the oil gradually evaporated, and assumed the form of yellow resin.^ Mr Proust observed, that when volatile oil is exposed to the air, it is partly converted into a resin, and partly into a crystallized acid ; usually the benzoic or the camphoric. Hence we see that the oil is con- verted into two distinct substances. During this change oxygen is absorbed ; and Fourcroy has observed that a portion of water is al& j formed.§ It is probable, from these facts, that resin is volatile oii deprived of a portion of its hydrogen, and combined with oxygen. All the resins have not the same tendency to unite with bases. Some indeed, seem to want that property altogether. Unverdorben has divided them into four classes. 1. Strongly acid resins. They dissolve readily in caustic am- monia. And the saturated ammoniacal solution may be boiled for a (juarter of an hour without letting the resin precipitate. When the solution is evaporated we obtain a super-resinate of ammonia. 2. Resins modernlely acid. They dissolve at the usual tempera- ture of the air in ammonia ; but when the solution is boiled for a quarter of an hour it is completely decomposed, the ammonia being driven oft' and the resin precipitated. The ammoniacal compounds of these resins are usually less soluble in water than those of the first class. But their acid properties are sufficiently strong to enable them to be precipitated from alcohol by an alcoholic solution of acetate of copper, and to dissolve by the assistance of a boiling heat in carbonate of soda, from which they drive oft' the carbonic acid. Both the resins of the first and second class, when dissolved in alcohol, redden litmus paper. 3. Resins feebly acid. They arc neitlier soluble in caustic am- monia, nor in boiling carbonate of soda ; but they dissolve in caustic ' Phil. Trans. 1804. X Creirs Annals, i. 1790. t Handbucli, ii. 14(». () Fourcroy, viii. hi TUnPENTlKE. 505 potash and soda. Their alcoholic solution is not precipitated by acetate of copper, but it is by an alcoholic solution of acetate of lead. The alcohol solutions of the resins belonging to this class do not redden litmus paper. 4. Neutral resins. They are not soluble in caustic potash or soda. But some of them dissolve in a solution of potash saturated with another resin. They generally pr'^cipitate when we add to the liquid an additional dose of caustic potash. So far as experiment has gone, the resins are all combinations of carbon, hydrogen, and oxygen. But the facts ascertained respect- ing these constituents will come in bettor when treating of the particular resins to which they refer, than they would do here. In describing the resins it will be convenient to divide them into two sets, namely, semifluid resins, or balsams, as they have been called, and solid resins. DIVISION I BALSAMS. The balsams owe their semifluidity to a certain quantity of volatile oil which they contain. It may in general be separated by distillation, and then the solid resinous body remains behind. The most important of the balsams arc the following : — 1 Turpentine. 5 Styrax. 2 Copaiva. 6 Opobalsamum. 3 Balsam of Tolu. 7 China varnish. 4 Balsam of Peru. Let us take a view of these balsams in the order in which they have been named. SECTION I.— or TUIII'ENTINE. The name turpentine has been given to a semifluid resinous body which exudes from various species of the pinus. Its properties differ according to the species of pine, the age of the tree, the time of the year when it is collected, and the climate in which the tree vegetates. ]3ut the great constituents of it are always colophan, or common rosin, and oil of turpentine. (1.) Common turpentine is extracted by incision from the pinus abies, or spruce Jir, and the pinus sylvestris, or Scotch Jir. It is thick, viscid, and has a greyish-yellow colour, a very slight smell of oil of turpentine, and a bitter burning taste. It is composed, as Unverdorben has shown, of a volatile oil, oil of turpentine, and two resins which he has distinguished by the names of pinic and silvic acids. Berzelius calls thein resin alpha, and resin beta of turpentine. The volatile oil varies from 5 to 25 per cent, of the turpentine. The two resins are no less various in their quantity. Unverdorben separated these three substances from each other in the following way : — The turpentine was mixed with water, and distilled to separate the oil. The rci^ivluo was diied aiul reduced to powder. Ill 506 RESINS. u It) 1^ 'i J] i 5* and digested in alcohol of 0'8()7 specific gravity. It dissolves the pinic acid, but leaves the silvic. At the same time with the pinic acid the iilcohol dissolves a small quantity of neutral resin, which may be called resin c. If we pour into this alcoholic solution an alcoholic solution of acetate of copper, the pinic acid is precipitated in combination with the oxide of copper. If we evaporate the alcohol and dilute it with water, the resin c precipitates. 1. The properties of oil of turpentine have been detailed in the preceding Chapter. 2. The properties of pinic acid have been given in detail in the work on the Chemistry of Inorganic Bodier, (vol. ii. p. 145). The pinates, or combinations of this substance witli the alkalies, niay be obtained by digesting an ethereal solution of pinic acid over the alkaline carbonates. The carbonic acid is driven off, and the alkaline pinate dissolves in the ether. The earthy carbona es, with the excc^ tion of carbonate of magnesia, are not decomposed hy this process. But the carbonic acid is driven off and a pinate formed, when we mix the carbonates of the earths with fixed pinic acid, or when we boil a solution of pinic acid in oil of turpentine over them. The greater number of these pinates dissolve both in melted pinic acid, and likewise in an alcoholic solution of that resinous acid, even when the salt is insoluble in pure alcohol. It is probable that in these cases a bipinate of the base is formed. The pinates, with bases of metallic oxides, ro ly be obtained by double decomposition. We must drop the metalline salt very slowly and cautiously into the alkaline pinate. If we adopt the opposite method by dropping the alkaline pinate into the metalline salt, the precipitate is mixed with a quantity of subpinate of the metalline base. These double de- compositions may be made by dissolving the salts, when that is practicable, in water, and when not, in alcohol. The pinates formed by Unverdorben, who has alone examined thenij have been described in the Chemistry of Inorganic Bodies, while treating of the salts.* 3. That portion of the resin which remains undissolved when the turpentine freed from its oil is digested in cold alcohol of 0'867, has been called silvic acid by Unverdorben, and resin beta by Berzelius. It h not quite free from pinic acid. To obtain it pure, dissolve it by boiling in twice its weight of alcohol of 0*807, and filter the solution while hot. During the cooling the silvic acid falls down in crystals, but still retains about 4 per cent, of pinic acid, from which it may be freed by repeated crystallizations. Its properties have been described in the Chemistry of Inorganic Bodies (vol. ii. p. 140) ; and the salts which it forms, in the Chapter in the same work on tie salts, have been enumerated and described, as far as they have been examined by Unverdorben. Henry Rose has concluded that silvic acid is a compound of 1 * See vol. ii. pp. 400, 440, 4C9, 492, 524, 539, 547, 577, 585, H'.o, 602, 609, 621, 649. 677, 686, 693, 699, and 713. i pimc which IS TURPENTINE. 507 atom oil of turpentine and 1 atom oxygen, or that it consists of Qio iiH o.* But Trommsdorf analyzed it, and obtained Carbonic acid . . . 78*73 Hydrogen .... 9*80 Oxygen 11'47 100-OOt If we adopt the formula of Rose, we get 10 atoms carbon = 7'5 or per cent. 78*94 8 atoms hydrogen =1*0 — — 10*53 1 atom oxygen =1*0 — — 10*53 9*5 100 Trommsdorf considers the composition to be C'° H^* O, a formula which comes nearer the result of his analysis, and which was con- firmed by a subsequent analysis of Liebig. But from the analysis of silvate of copper, Trommsdorf reckons the atomic weight of silvic acid 37*75 = 4 (C" H^* O). This gives us the composition 40 carbon = 30 or per cent. 79*4 30 hydrogen =3*75 — — 9*9 4 oxygen =4 — — 10*7 37*75 100 (2.) Venice turpentine comes from Styria, Hungary, and the Tyrol, and is extracted from the pimis larix, or common larch. It is limpid, transparent, and has a light-yellow colour, and the con- sistence of honey. Its smell is disagreeable, and its wste bitter and hot. It must be many years exposed to the air before it becomes hard and brittle. It contains from 18 to 25 per cent, of oil of tur- pentine, winch is extracted by distilling it with water. What remains is colophan, or common rosin. Venice turpentine dissolves slowly in alcohol, without leaving any residue. The caustic alkalies dissolve it easily, and no doubt com- bine with its acid resins. If Venice turpentine be mixed with caustic potash ley it dissolves, wnile a white flocky matter precipi- tates. The solution is limpid and yellowish-brown. Its taste is not alkaline, and it may be evaporated in a gentle heat without any oil being disengaged. When evaporated till it becomes solid it is opaque and wrinkled. It dissolves readily in water, but separates when we pour into the solution a certain quantity of carbonate or hydrate of potash. Soda acts precisely in the same manner with this turpentine as potash. Very concentrated ammonia has little action on Venice turpen- tine, but when diluted it dissolves the greater part of the turpen- tine by the assistance of heat. The undissolved portion assumes the appear nee of a gelatinous mass, and the solution has a yellow- * Poj-'^cridort s Annalon, xxxiii. 4J t Ann. flor Pharraacic, xiii. 171. il / S hi 508 KESINS. I I ish-brown colour. On cooling the whole concretes into a gelatinous solid, while a brown liquid separates, which may be decanted off. When this mass is mixed with water it becomes white. When agi- tated in from 40 to 50 times its weight of water it forms a milky liquid, which in about 12 hours concretes into a white soft jelly. The turpentine thus treated is divided into two substiinces, which have distinct properties. rt. The Umpid, yellow liquid which separates from the jelly before and after the dilution, and which passes through the filter, is a com- bination of ammonia with a resin, which contains no volatile oil. If we saturate it with an acid the resin precipitates in powder, and may be collected and washed on a filter. It is a white, light, frial "i matter, with an earthy fracture. It melts at the temper'vture of boiling water, or a little higher, and then has the appearance of common rosin. When assisted by a boiling temperature, naphtha dissolves a portion of this resin, and assumes a brown colour; but during the cooling the resin precipitates, and the naphtha becomes colourless as at first. h. The gelatinous part of the combination of ammonia and Venice turpentine, when dried in the open air, has a yellow colour, is transparent and adhesive like the turpentine itself. It consists of the ammonia combined with a resin, and with oil of turpentine. In proportion as the ammonia is driven off, the turpentine is regenerated, but it is softer than before, because it contains less resin. By mix- ing it with acidulated water and distilling, the oil is removed, and a resin remains, which ditfers from the resin in the liquid portion in being soluble in naphtha. A solution of turpentine in potash precipitates the salts which have the alkaline earths, and the metallic oxides for bases. These precipitates are insoluble in water, and when distilled with water after having been dried, they give off oil of turpentine. They have no smell, and seem at first destitute of taste, but by degrees the acrid taste of oil of turpentine becomes perceptible. Unverdorbcn analyzed fresh Venice turpentine, and obtained : 1. A volatile oil easily distilled off. 2. An oil not so easily dis- tilled, and having a great tendency to be converted into a resin. o. Succinic acid, which is found dissolved in the water with which the turpentine is boiled, in order to drive off the volatile oil. 4. Three different resins, which were separated in the following man- ner: — The turpentine freed from its oils was dissolved in alcohol of 0'873, and the solution was precipitated by an alcoholic solution of acetate of copper. This precipitate consisted chiefly of pinate of copper mixed with a very small (juantity of silvate of copper. These two acid resins Avore separated in the way already stated. The solution, which had been precipitated by acetate of copper, was evaporated to dryness, the acetate of copper which it contained was dissolved out by water, and the resin taken up by alcohol of 0*873, which left, without dissolving it, a small quantity of pinate of c()j)per. When the alcoholic solution is evaporated to dryness, nnPENTINK 500 tlio third resin rcmaiDs. It is colourless, ami has a stroni? resinous lustre. It is insoluble in alcohol and naphtha, and belongs to the class of neutral rosins. (3.) French turpentine is obtained from tlie pinus maritimn, which grows in the south of France. It resembles Venice turpen- tine, and is considered as possessed of nearly the same (lualities. When turpentine is kneaded with j'.jth of its weight of mag- nesia alba, a combination takes place gradually, and after six or seven days the mixture become? firm. Faure, who first observed this effect, has recommended this combination as a convenient mode of administrating t rpentine internally as a medicine.* This properly belongs to the turpentine from the pinus maritima, but not to that from the pimni picea.'\ (4.) Strasburg turpentine is extracted from the pinus picea. It is pale yellow, transparent, and more licjuid than Venice turpentine, and has a smell which is rather agreeable. It has been subjected to an interesting examination by M, Caillot. According to him it is obtained not only from the pinus picea, but also from the pijius abies.X When he distilled off the volatile oil along with water, be found that the water contained in solution a »[uantity of succinic acid. He digested it in boiling water till every thing soluble in that liquid was taken up. He then treated it with cold absolute alcohol, which left und'^ ed a neutral resin. It is colourless, and is insoluble in cold alcoliol, in naphtha, and in caustic potash. It differs by its insolubility in alcohol from the neutral resin in Venice turpentine. The alcoholic solution being evaporated, left a resinous mass, which was boiled in a solution consisting of twice its weight of car- bonate of potash. The mixture ' ^ concentrated by evaporation, and the alkaline licpior decanted if. The residual compound of resin and potash was mixed with from 25 to 30 times its weight of water, and the whole left at rest. There was deposited at the bot- tom of the vessel a mass of crystals. Tiiis mass, freed from the liquid in which it was deposited, was dissolved in alcohol, and the solution was left to spontaneous evaporation. The resin was deposited in pyramidnl crystals, to which Caillot gave the name of abietin. It is destitute of smell, and has little taste. It is very fusible, and becomes soft when exposed to the direct rays of the sun. When in a state of fusion, it is colourless and limpid, and looks like melted tallow. On cooling it concretes into a white, opaque, crystalline mass. It is insoluble in v/atcr; but dissolves realily in alcohol of 0*833, and in every proportion at a boihng heat. It is soluble in ether, in na])htha, and in concentrated acetic acid, and crystallizes when these liquids are volatilized. It is in- soluble in potash. The resin dissolved by the alkaline carbonate appears to be a mixture of pinic and silvic acids. Caillot has given it the name of * Jour, do Pliarmacir, xvii. 10"2. \ ll)i.. 495. f Id. Und m m III ** Berlin Jahrl). xxvii. 2, 179. I r 512 UKSINS. not separate, hut it is disoiif^.i^^otl when a conrti(l(>ral)le portion is addtul. Schweitzer has shown that the presence of a fixed oil in this halsani may be detected hy aijitatinjj;' it with caustic anunonia. The iiunnonia becomes milky only if the oil be present.* Halsam of copaiva unites when heated with sidphur and |)hosphoru8. Sometimes it dissolves as nnich as half its weij'ht of sulphur. Uoth of these bodies are thrown down by absolute alcohol. Halsam of copaiva absorbs chlorine ^as, becomes muddy, and muriatic acid is formed. Iodine is dissolved in it by the assistance of heat, fxiving it a dark red coloin*. It combines with sidphuric acid, assumini; a red or brown colour, while sulphurous acid is disengaged.f The balsam becomes viscid. Concentrated nitric acid attacks it violently. Dilute acid has less action ; but transforms it into a hard yellow resin, a portion of which dissolves in the acid at the same time, with a yellow bitter substance soluble in water and in alcohol. Muriatic acid g'ives co- paiva a red colour, but scarcely dissolves it. It may be mixed with concentrated acetic acid, but it becouu^s muddy, and allows an .iqueous litpiid to fall to the bottom, while the balsam, dissolved in anhydrous acid, swims on the surface, lioracic, succinic, and benzoic acids are dissolved in small quantities by this balsam. The best way is to dissolve them in absolute alcohol, mix the solution with the balsam, and then evaporate the liquid to drive off the alco- hol. Aqueous solutions of oxalic and tartaric acids dissolve a little of this balsam. Balsam of copaiva combines readily with the salifiable bases. When we mix 3 parts of balsam with a solution containing ^th of its weight of hydrate of j)otash, a complete cond)ination takes place with the disengagement of heat, and we obtain a limpid licjuid. If we add an additional dose of potash, the liquid becomes nnuldy, and a still greater quantity causes the cond)ination of the balsam and potash to separate and swnr. on the surface. This comj)ound dis- solves in water, and when left to itself a small quantity of neutral resin precipitates. In spirit of wine this conqiound forms a linqtid solution ; but the solution of it in absolute alcohol is muddy. It is soluble in ether, and also in a great measure in naphtha.J it cannot be dried completely without undergoing deconqiosition. With soda it exliibits the same ])lienoniena as with potash. The same remark applies to anunonia. 1 ])art of licpiid ammonia, of specific gravity 0''J(i, mixed with 8 parts of balsam, forms a lim- pid li(juid.§ When we dcmble the quantity of ammonia, the liciuid * Pogtrendorf's Aiinalcii, xvii. 487. f In France copaiva is alien adulterated with castor oil. This ailiilteration M. Pianche has shown may bo detected hy means of sulphuric acii1. A lew drops ot' pure copaiva, mixed with the same (|uaniiiy ot" acid, assume a yellow colour, which persists tor some lime. But it' castor oil be present, the yellow colour becomes immediately weak, and speedily disappears. See .lour, du I'harmacie, xi. 231. X See Gerber, .Tour, de I'harmacie, svi. 71. § The solubility oi' id iiddy. It is 4 It cannot otasb. lid ammonia, forms a lim- lia, the liquid adulteration M. A few drops <>t o\v colo\ir, wliifH ; colour becomes inueie, xi. 2:31. begins to get muddy, and if wo inerease the (juautity of ammonia still farther, a separation of the rKjuid takes nlaee into two portions.* It is then unetiious, g/ ' .olo in weak aleoliol and in ether ; but al- most insoluble in absolute alcohol, and in the fixed oils. Sehweit/er found that when !) j)arts of (topaiva are agitated in 2 parts of licjuid ammonia, of the specific gravity 0-95, and then left at the tempera- ture of 50°, crystals of a neutral resin are gradually deposited. If we wash these crystals in ether, and dissolve them in alcohol, wo obtain larger, but less regular crystals. They are white and trans- lucent. They are four-sided prisms, very nearly rectangular, the angles being 90° 30' and 89° 30'. The acute eclge of the prism is usually replaced by a tangent plane.f They are at first soft, but by exposure to the air become hard and britth?, without losing their transparency. They contain no ammonia.t With the other salifiable bases balsam of copaiva forms insoluble compounds, which m.iy be obtained by double decompositi*. .i. They liave the consistence of plaster ; their smell is analagous to that of the balsam ; they are little soluble in absolute alcohol ; but they dissolve i"» ether, naphtha, and the volatile oils. They are soluble also in balsam of copaiva, and increase its consistence. The affinity of magnesia for this balsam is remarkable. 1 part of magnesia dissolves in 30 j)arts of balsam, into a transparent li- quid. When we agitate balsam of copaiva with a solution of a me- tallic subsalt, it combines with the excess of base, and the salt, held in solution by water, becomes ntJutral. The following table shows the composition of this balsam, as determined by Stoltze and Ger- ber :§ — Volatile oil . Yellow hard resin . Brown soft resin Water . Stoltzu. nEkUER. Fresh Balsam. Old Ralsatn. 45-59 52-75 I'iiC) 41 51-38 2-18 5-44 31-70 53-G8 11-15 4-10 100-00 100 100-63 According to Durand, the balsam contains besides a fatty sub- stance, whicli remains when we dissolve it in a sufficient quantity of alcohol of 0-842. It is insoluble in ether and in absolute alcohol. 1 . The volatile oil is not easily obtained from the balsam by distil- lation. When we distil with water, we must repeat the process seven or eight times, in order to procure all the oil. If we distil the oil alone, it does not come over till the balsam is heated to 500°. But, according to Ader, we may separate the oil without having recourse to distillation. If we agitate 100 parts of alcohol, of 0-836, with vbt uotieccl A by M. * See Gcrlior, Jour, do I'li;U!niic'iC, xvi. To t Ibid. .\\i. 17-2. . 2 I § Jour, de Pliariincio, xvi Pogg;oudorf, xvii. 4Sf). " 7l» and 307. .')14 nKSINS. 100 pnrtH of halHam of copaiva, add 37^ parts of caustic alkali of the Btrongth used by tlio soap-niakor, agitato fitrongly, and pour the wholo into ISO parts of water, the oil separates by little and little, and may ho decanted off. This oil is transparent, slightly yellow, and has a specific gravity of 0*880. It is soluble in alcohol. It dissolves caoutchouc without destroying its elasticity. It appears to contain no oxygen, for po- tassium may be kept in it without losing the metallic lustre. Such are its properties, when obtained by simple distillation from the balsam. This oil was analyzed by Blanchet, who obtained Carbon 8G-H9 Hydrogen .... 11*70 This gives the formula 10 atoms carbon 8 atoms hydrogen 1)8-59 =r 7*r)0 or per cent. 88*23 = 1-0 _ _ 11-77 8*5 100*00 This oil boils at 473°. Tin melts in it with great facility. When obtained by distillation with water it is limpid and colourless, has an acrid taste, and the smell of copaiva. It reddens litmus paper, .ind has a specific gravity of 0*91, but l)(>cominr, Golilcn's Jour. vi. 467. t Gehlen's Jour. vi. 491. I HHtclictt/riiiril Scries ot Exporitnonts on Artificial THiinin, I'hil. Trans, 1806. $ Berl, Jalirbucli, xxv. '2. v?l-. BALSAM OF PERU. 519 bstance, es it an id witli a receiver lonate of 8, which, indicates !oic acid learance, jcipitates hie result ; residue al tannin less than I is com- perties : — 5. Hence on per se. Is the fol- 2 parts of 3mains un- ill dissolve le benzoic ed into the bottom of with water which will iporate the low colour, t evaporate Its specific oiling point m, showing vi. 491. I. Trans, 1806. clearly that balsam of Peru contains a number of oils differing from each other in their volatility. There remains in the retort a bulky charcoal. The oil distilled over is light-yellow, very fluid, a little heavier than water, and has a rancid but not empyreumatic smell. It dissolves readily in alcohol of 0*860, and likewise in hot potash ley. It is insoluble in water, may be mixed in all proportions with absolute alcohol, but requires 4 times its weight of alcohol of 0*860 to dissolve it. It may be mixed with ether, oil of turpentine, and olive oil. Concentrated sulphuric acid dissolves it, and water precipitates it from this solution. Nitric acid acts upon it slowly, and seems to convert it into an acid similar to the fatty acids discovered by Chevreul. Concentrated acetic acid dissolves a small quantity of this oil, which is again precipitated by water. It seems to have the property of combining with potash, and of forming a kind of soap. In this, and several of its other properties, it approaches nearer to a fixed than a volatile oil. 2. The resin, very soluble in alcohol, precipitates when we mix the balsam with olive oil. Stoltze's method of procuring it is this : 1 part of the balsam is well agitated with 6 parts of alcohol of 0*860. Tile resin, little soluble in alcohol, remains undissolved. The alcoholic solution is evaporated to dryness, and the residuum mixed with 12 parts of hot olive oil, which dissolves the oil and the benzoic acid and leaves the resin. To make it pure, let it be treated with another similar dose of olive oil, and then dissolved in alcohol of 0*860. Should the solution contain benzoic acid, it is to be saturated as exactly as possible with carbonate of potash ; hot water is poured into the liquid, and the alcohol is evaporated. The resin remains in a state of purity, and if it be melted in a moderate heat, the water which it may retain is driven off. This resiu has a deep brown colour, is destitute of taste and smell, and melts at a heat under 212°. It is insoluble in water and in ether, provided it be free from alcohol. It is insoluble also in oil of turpentine and olive oil. But it is very soluble in alcohol of less specific gravity than 0*871 . The addition of water renders the liquid milky ; but it is difficult to collect all the precipitated resin. Sulphuric, nitric, and acetic acids dissolve it with facility, but water throws it down from these solutions. It is very soluble in the caustic alkalies. By an excess of alkali the combination is separated from the liquid. The alcoholic solution of this resin gives a green colour to the alcoholic solution of protochloride of iron, and throws down from the alcoholic solution of acetate of lead a brownish-grey precipitate, which is soluble in acetic acid. The same alcoholic solution of the resin renders muddy a solution of gelatine. 3. Resin little soluble in alcohol. It is blackish-brown, very brittle, destitute of taste and smoU. When moderately heated it melts, giving out the smell of benzoin. It is soluble in boiling absolute alcohol ; but the solution becomes nuiddy on cooling. It is insoluble in ether and in oils of turpentine and olives, (^oncen- i "I i Ifl II'. If 520 llESINS. tratetl sulphuric acid dissolves it ; nitric acid decomposes it ; and acetic acid has no action, at least cold. By the assistance of heat it combines with the caustic alkalies, and acids separate it from these bodies unaltered. The alcoholic solution of this resin is pre- cipitated by acetate of lead dissolved in alcohol. The precipitate is dissolved by acetic acid. SECTION IV OF BALSAM OF TOLU. Thu substance is obtained from the tulifera balsamum, a tree which grows in South America. The balsam flows from incisions made in liie bark. It comes to Europe in small gourd shells. It is of a reddish-brown colour and considerable consistence ; and when exposed to the air it becomes solid and brittle. Its smell is fragrant, and continues so even after the balsam has become thick by age. When distilled with water it yields very little volatile oil, but im- pregnates the water strongly with its taste and smell. A quantity of benzoic acid sublimes, if the distillation be continued.* Mr Hatchett found it soluble in the alkalies like the rest of the balsams. When he dissolved it in the smallest possible quantity of lixivium of potash, it complt^toly lost its own odour, and assumed a most fragrant smell, somewhat resembling that of the clove pink. " This smell," Mr Hatchett observes, " is not fugitive, for it is still retained by a solution which was prepared in June, and has remained in an open glass during four months." When digested in sulphuric acid, a considerable quantity of pure benzoic acid sublimes. When the solution of it in this acid is evaporated to dryness, and the residue treated with alcohol, a por- tion of artificial tannin is obtained ; the residual charcoal amounts to 0-54 of the original balsam.f Mr Hatchett found that it dissolved in nitric acid with nearly the same phenomena as the resins ; but it assumes the odour of bitter almonds, which leads him to suspect the formation of prussic acid. During the solution in nitric acid, a portion of benzoic acid sublimes. By repeated digestions it is converted into artificial tannin. $ It dissolves completely in alcohol, ether, and the volatile oils. The fixed oils dissolve it incompletely. SECTION V OF LIQUID STYUAX. What is called liquid styrax in this country, and by the French, haulme de copahne, or liquid amber, is a juice which exudes from the lifjnidamhnr fttyracijiua, a tree which grows in Virginia, Mexico, and some other parts of America. But there can be no doubt that styrax was known to the Arabians before the discovery of America, and that it was brought to them from India. The oriental styrax ' Lewis, Neumann's Chem. p. 285. I IlatcIiLtt, Tliini Seiios of Kxpcriments on Aititicial Tannin, I'iiil. Trans. 180G. I ll)i(]. sr el i I .IQUin ST"UAX. 521 ; anil if heat ; from .3 pre- ipitate a tree cisions , It is i when agrant, by age. )ut im- [uantity t of the .ntity of sutned a ve pink, it is still cmained of pure acid is 1, a por- amounts 3arly the of bitter jsic acid. :oic acid artificial itile oils. 3 French, from the , Mexico, ioubt that America, ital styrax I'liil. Trans. is the produce of the Uqnidamhar alliiujia, a tree which is a native of Java.* Almost the whole of the styrax which occurs in com- merce, has acquired from age nearly a solid consistence. But M. Bonastre was fortunate enough to obtain a fresh specimen which had been sent to Marseilles from South America. The following are its characters in that state : — It has an oleaginous consistence, and is more or less transparent according to the temperature of the air. It has a strong smell, the same as that of liquid styrax of commerce. Its taste is acrid, sharp, and very aromatic. Its consistence depends upon the temperature. At 59° it is about equal to that of balsam of copaiva. At 32° it is very thick, and has lost its transparence. At 24° or 25° it is almost quite opaque, and seems to have a tendency to crystallize. This is owing to one of its immediate principles. Its specific gravity is less than that of water. Hence if dropt cautiously on water it spreads on the surface. But when let fall from a height it sinks to the bottom, and remains there : its levity not being sufl[icient to over- come the cohesion of the particles of water above it. Alcohol at 91°^ dissolves about rds of it. The solution very slightly reddens litmus paper. The portion not dissolved is a white mass, consisting of a congeries of crystals. Ether dissolves it in all proportions. The solution is not quite transparent. This recent balsam of styrax was subjected to a chemical analysis by M. Bonastre, who obtained \ Volatile oil • 7-00 2 Semiconcrete matter • ll-l 3 Benzoic acid • 10 4 Crystalline matter soluble in") 5-3 water and alcohol 5 Yellow colouring matter , 2-05 (J Oleo-resin . • 49-0 7 Styracin • 24-0 99-45 The volatile oil was obtained by distilling the balsam along with water. It is liquid and transparent and colourless like water. It is lighter than water, but heavier than alcohol. Its smell is strong, and quite similar to that of liquid styrax. Its taste is acrid and burning, leaving a very disagreeable impression in the mouth. It communicates to water its taste and smell, though it dissolves only in minute quantity in that liquid. When distilled with precaution we obtain two products. 1. A transparent oil, having a strong aromatic taste and smell. 2. Towards the end a whitish, solid substance destitute of smell, and of the consistence of yellow wax. When dissolved in ether, it unites by evaporation into numerous small globules. The volatile oil congeals at 32° It is then a semitransparcnt !il! ^■^ Jl: our, dc I'liiirinacio, xviii, 711, ,^ %# I 622 RESINS. i; I m^.M H mass lik!j camphor, but without any appearance of crystallization. Nitric acid converts it into a yellow resinous matter having the colour of gamboge ; but no benzoic acid is formed. This volatile oil was analysed by M. O. Henry, who found it composed of Carbon . . HO'Sfi or !0 atoms Hydrogen . . h)"4(i or 7 at.om'5 if this aiialysib be correct, tlis vokrlo oil ''.IfFer? frnni }M of tur- pentine, iemon, ju:;iper, pepjiijr, anJ tHbiiK;, by coataau:;;,' an atom of hydrogen less united to the same v<..vmber of atoms of carbon as in those oils The scmnoncrete lu.vttcr existed in tlie water distilled over with the volatile oiL It was obtained by agitating that liquid wit.i ether. It wap similar to the whit(^ nati.er ol/taincd by distiiliity the volatile oil. The water remaining in the re<^ort b^iiiiR filtered had a yellow colour. Keiiig concentrateu it iJt'positc;! a v 'if crysralline matter in small ;;lohuJes. This constitutes the crystalline matter soluble la watoi* and alcohol. From the account jjiven of it bv Bonastre, It .Huoras to have some resemblance to cotcmairin. The oleo-resin had an oily aspect, and was soluble in alcohol and ( ther. It was probably composed of an oil and a resin. After the balsam had been boUod for 40 hours in water, it might be concluded that all the volatil*: oil had been separated, yet it still retained its soft consistence. It was boiled with lime and water, filtered, and decomposed by an acid. The whole was thrown on a liltcr, dried, and being introduced into a glass tube, was sublimed. Benzoic acid was by this means obtained. When the balsam is treated with alcohol, about a fourth part remains undissolved, constituting a white crystalline mass. This is the substance which M. Bonastre has distinguished bv the name of styracin. The crystals consist of four-sided pyramids. They are insoluble in water, both cold and hot. Cold alcohol dissolves but a very small proportion of them. They dissolve in boiling alcohol, but are deposited in little spherical masses, consisting of congeries of crystals, as the liquid cools. They have the consistence of yellow wax. Their smell has some resemblance to that of vanilla. They have little or no taste. They melt at a heat below that of boiling water. They have no action on vegetable blues. These crystals were analyzed by M. O. Henrv, who obtained Carbon 7<)-2728 or 1 1 atoms = 8-25 or per cent. 75-86 Hvdrogen 5-5032 or 5 atoms = 0-(;25 — — 5'74 18-2240 or 2 atoms = 2-00 — — 18-40 Oxygen 100-OOOOt 10-875 100-00 Jour. (!c riiurinacic, xsii. 314. f Ibid. xvii. 850. BALM OF MECCA. 523 lization. •ing the 1 volatile of 'J of tur- an atom carbon as r with the :>ther. It olatile oil. I a yellow ne matter er soluble Bonastre, in alcohol sin. r, it might yet it still md water, irown on a sublimed. burth part iss. This \f the name c insoluble but a very Icohol, but ;ongerie3 of • smell has or no taste, ley have no d by M. O. it. 75-80 5-74 18-40 SECTION VI OF Ol'OBALSAMUM, OR BALM OF GILEAD BALM OF MECCA. This balsam is obtained from the amyris Gileadensis, and amyris opobalsanmm, a tree which grows In Arabia, especially near Mecca. It is so much valued by the Turks, that it is seldom or never im- ported into Europe. It is said to be at first turbid and white, and of a strong aromatic smell, and bitter, acrid, astringent taste ; but by keeping it becomes limpid and thin, and its colour changes first to green, then to yellow, and at last it assumes the colour of honey, and the consistence of turpentine.* VVi.cn rubbed between the hands, it is said to froth like soap. When poured into water, drop by drop, it spreads upon the surface of the liquid, and mjiy be easily skimmed off by a feather. These two properties are considered as proofs of the goodness of opobal- samum. It does not dissolve completely in alcohol even when assisted by heat. A transparent substance analogous to resin is left, having an agreeable smell. Alcohol of 0-815 dissolves, when assisted by heat, jds of this substance, and leaves a flocky matter, thready when hot. The hot solution docs not become nmddy on cooling, and when left to spontaneous evaporation it deposits a few flocks of a transparent substance, similar to turpentine. Trommsdorf examined opobalsamum, which came to him from Petersburg in leaden flasks. Its specific gravity was 0-950, at the temperature of 71°^. It had a peculiar odour, analogous to that of oil of lemons, or rosemary. When exposed to the air it was speedily converted into resin. He found its constituents to be Volatile oil . . . . 30 Hard resin . . . . ()4 Soft resin ..... 4 0-4 Bitter colouring matter 98-4 1 . The volatile oil, obtained by distillation with water, is colour- less, fluid, and has a very agreeable odour. Its taste is acrid. It dissolves in alcohol, ether, naphtha, and the fixed oils. Iodine is dissolved by it. Sulphuric acid dissolves it, assuming a dark-red colour, and water throws it down converted into a resin. Nitric acid converts it also into a resin, and communicates the odour of musk. It is soluble in concentrated acetic acid, but the caustic alkalies do not dissolve it. It is very easily converted into resin. 2. The hard resin is obtained by treating what remains after distilling off the oil with concentrated alcohol. The soft resin re- 100-00 ;i,;n. * This is the account of Professor Alpinus, as ([uotcd bv Lewis, Neumann's Chcm. p. 284. 524 UESINS. mains while the hard is dissolved, and may be easily obtained by evaporating the solution. It is honey-yellow, transparent, brittle, and has a specific gravity of 1'333. At 1 1 1° it becomes as soft as turpentine, and at \dO° it is in a state of comj)leto fusion. Alcohol and ether dissolve it with the assistance of heat with great facility. The solution goes on cold, but not so well. Both the fixed and volatile oils dissolve it. Sulphuric acid dissolves it, assuming a deep orange-red colour, and water throws it down from this solu- tion. Nitric acid of 1*25 scarcely acts on it, but concentrated acid decomposes it, while oxalic acid is formed, together with a yellow unctuous matter. 3. The s()ft resin is brown and very adhesive, yet it may, by degrees, be dried. It softens at 212°, and melts at 233°{f. It is insoluble in alcohol, but soluble in fixed and volatile oils. Sulphuric acid does not dissolve it.. Nitric acid causes it to swell, and renders it friable and yellow. Alkalies have no action on it. Balm of Gilead has a high reputation among the Turks as an internal remedy. M. Bonastre examined a specimen of opobalsamum that had been sent to Napoleon for the Empress Maria-Louise, and consequently genuine.* By distilling it with water he obtained 10 per cent, of volatile oil. Its specific gravity was 0*87(), it was quite transparent, had an agreeable turpentine smell, and a strong, sharp, aromatic taste. It dissolves in 12 times its weight of cold alcohol. Ether dissolves any quantity whatever. Acetic acid dissolves vory little of it. Nitric acid, cold, has little action on it. Sulphuric acid gives it a red colour. It does not becon.e solid though cooled down to 10°^. It does not combine with the alkalies. The water had dissolved 4 per cent, of a brown, bitter extract, partly soluble in alcohol, and communicating to it a bitter taste. The resin was dissolved in alcohol. The alcohol being driven off the resin remained viscid, and never acquired the solidity of resin from turpentine. It combines but imperfectly with the alkalies. It is but little acted on by nitric acid, even at a boiling heat, and no crystallizable substance is formed. To the portion of resin insoluble in alcohol, Bonastre has given the name of burseriu. It is solid, tasteless, and without smell. Its colour is greenish-white. It softens when heated, and cannot easily be reduced to powder. Very little soluble in boiling alcohol, and separates in white flocks as the solution cools. It dissolves readily in ether, but the solution does not yield crystals. It resembles very much the insoluble portion of the balsam from the hursera guinmi- fera. This is the reason why Bonastre has called it burserin. The following table shows the proportions of these constituents, obtained from 100 parts of opobalsamum by Bonastre: — * Jour, lie riiarmacic, x\iii. Oj. nosiN, OH rOI-OFAN. 525 iiiod l>y brittle, 1 soft as Alcohol tac/ility. xcd and uniing a \is solu- ted acid yellow a may, by U It is ulphuric I renders ■ks as an had been scquently )f volatile irent, had atic taste, dissolves ttle of it. id gives it mto 10°^. er extract, r taste, ling driven solidity of he alkalies, heat, and } has given smell. Its mnot easily dcohol, and Lves readily cmbles very era gummi- ir serin. jonstituents, Soluble viscid resin Bursorin Volatile oil Bitter extract Acid matter ? Impurities . 70 12 10 4 3 1 100 Canada balsam in commerce is sometimes substituted for opobal- samum. They arc easily distinguished by the resins if each. The alcoholic solution of opobalsamum yields a viscid soft resin, that of Canada balsam a solid brittle resin. SECTION VII. — OF CHINA VAHNISH. This is a natural bjilsam, cm])loyed in China as a varnish. According to Boureiro, it comes from a tree called migia si7iensh, which grows in Cochinchina, China, and Siam.* It has the same consistence as turpentine, a brownish-yellow colour, an aromatic odour, and a strong astringent taste. It spreads on the surface of water, imbibing a little of that licjuid, and becomes, at the same time, colourless and transparent. When the water is evaporated the balsam recovers its original appearance. It is composed of a colourless oil, having a strong smell, which may be distilled off along with water, of benzoic acid, and a yellow resin. It is soluble in alcohol, ether, and oil of turpentine. It is insoluble in caustic potash .f This balsam constitutes the best varnish hitherto discovered. It mixes well with colours, and gives a very solid and beautiful covering. DIVISION II.— SOLID RESINS. These bodies are exceedingly numerous, having been extracted from a great variety of vegetable substances, and described more or less in detail by different chemists. But it would be an unpro- fitable waste of labour to collect all the facts on this prolific subject, scattered through an almost infinite number of books. It will be sufficient if those resins are described which occur in large quantities, and have been applied to purposes of utility. SECTION I. — OF ROSIN, OR COLOFAN. This is the nanie given to the resin which the different species of turjientincs leave when they are deprived of their volatile oil by distillation. After this process it is melted with about ^d of its weight of galijwt,X placed upon a straw filter, and a little water is * .Tour, lie Pharmacio. xv. 52.'j. •j- Macaire-Princpj), .Tour, do Pharniacie, xv. 52.}. X Galipot is a mixlMro of resin from the pviits abies and syhesti-is, which occurs in commerce in yellowisii-grcy pieces, v.irying much in s^ize, soft wiiliin but hard on tiie surface. It is notliinyr else than common turpentine, deprived of a portion of its oil. HF •I :!■ f I .526 RE8IN8. sprinklctl on the melted mass. Tims prepared, it 'u common rosin, or resin. Wlien it has a golden-yellow colour, it is called Bur- (juruhj pitch. It has a deep brownish-yellow colour, is translucent, brittle, find has a specific gravity of 1"08(). It softens at 150°, and melts at 275°. It is composed chiefly of what I'nverdorbcn called pinic acid, a substance wnich has been described in a ])rccceding part of this Chapter, while treating of turpentine. This resin is very easily altered into a brown resin, ])0S8essing more powerful acid characters, to which Unverdorbeu has given the name of colophonic acid. This change is produced by distilling pinic acid in a retort, till only ^ths of it remain in the retort. Common rosin contains variable quantities of coloj)honic acid, according to the heat employed in pre- paring it. Sometimes it amounts to Jlth of the weight ut the rosin. It is but little soluble in alcohol of the specific gravity O-STD ; but the solubility is increased when it is mixed with pinic acid. The salts which it forms with bases have been described by Unverdorben in detail. Hut they are so similar in their characters ^0 the pinates, that any description would be little else than a repeti- tion of what lias been already stated, when giving an account of turpentine.* lilancliet and Sell have shown that rosin is a compound of I atom oil of turpentine, and 1 atom oxygci ; or that it consists of Qio jjH Q -j- jj^ Rose has ascertained that the resin from (ropaiva has exactly the same . institution. | Rose analyzed the crystallized resin of colophan, and obtained Carbon 79' 15 or 10 atoms = 7*5 or per cent. 78*94 Hydrogen 9*93 or 8 atoms = 1 — — 10-53 Oxygen 10-92 or 1 atom =1 — — 10-53 100-00 9-5 100-00 He analyzed the colophonates of silver and lead, and found the com- position the sauie as those into which the crystallized resin of copaiva enters. Hence the atomic weight of this resin is 38, and its com- position 4 (C" H» O), or 2 (C'« PP O). The mwrystallizable resin of colophan, called silvic acid by Unverdorben, has been found by Rose to have the same atomic weight as the crystallizable resin. § We are indebted to M. PVemy for an important set of experi- ments on the products of rosin, when distilled per se, or along with lime. II To free the rosin as completely as possible from oil of tur- pentine, it was heated in a retort, a good deal of water and oil of turpentine at first escaped, and the heat was continued till these substances ceased to conii* over. When the heat is now increased, there passes over a very heavy, ♦ See Poggendorf's Annalcn, vii. 311. X Ibid. xxxiii.3j. § Ibid. |). 45. f Ibid. xxix. 133, Ann. der Pharrn. xv. '282. UU8IN, Oil COLOI AN. 527 rosm, I Bur- lo, and (ilts at rtciV/, a of tills easily racters, ThU ily jths variable I in pre- e rosin. 79; but ibcil by laracters a repeti- count of ind of 1 insists of 1 copaiva ystalli/ed 8-94 0-53 0-53 10-00 1 the com- uf copaiva d its com- c acid by me atomic of experi- alonji with oil of tur- and oil of I till these ^ery heavy, :. 133. in. XV. '28'2. \ light-coloured on, almost destitute of taste and smell. It is scarcely soluble in alcohol, not at all in water ; but exceedin < given the name oiresinonCf was analyzed by him. He found the coastituents to be Carbon 77*81 or 10 atoms = 7*5 or per cent. 77-93 Hydrogen 11-76 or 9 atoms = 1-125 — — 11-08 Oxygen 10-43 or 1 atom =1 — — 10-39 100 9-025 100 It therefore differs from oil of turpentine, by containing an addi- tional atom of water. )Vhen, after the separation of the j'esinone, the distillation is con- tinued, we obtain a less volatile oil, \\iilch has a less burning taste. Ki I fl I f'i M fH 1(1 if '; 11^ A3H TtKNINS. boils at 208° J, and id sonu^vvliat loss BoliihU' in alcoiiul thar. reaiiiono. Accordinjf to tlie analysis of Kniiny it is •< ■ po^^v .1 .;f Carbon H.'MM or 2:J atoms = 17-2.'i or j)er cent. 84*14 Ilyilroiron ll-IO or IS atoms = 'i-Hf) - _ l()-i)H Oxv|?en 4-!J*) or I atom = I "5 - - — 4-88 100 20 100 To Uiis 8ubstant'arent, not utdike mastich, but rather more transparent and brittle. When chewed it does not soften as mastich does, but crund)les to powder. Mr Matthews found it almost completely soluble in eight tnues its weight of alcohol. The n^sidue was extraneous matter-J it does not dissolve in tallow or oil, as common resin does.§ Mr Hatchett found it soluble in alkalies and acids with the same phenomena as connnon resin. It melts at IlOH", and froths, giving out an agreea- ble smell. Unverdorbcn has analyzed sandarach, and 'wis found it composed of three resins. If we dissolve it in absolute alcohol, and add a solution of hydrate of potash to the liciuid, a resinati' of potash pre- cipitates in the form of a viscid mass. When the liquid is left at rest in a cool place, it gradually deposits an additional (juantity of this resinate. It retains in solution the compound of potash with the two other resins, which may bt; thrown down by pouring into the rKjuid very dilute nuiriatie acid. The mixture of these two resins thus precipitated is washed and dried, and then boiled In alcohol of the specific gravity 0*879, which dissolves the one and leaves the other. The resin thus dissolved by the weak alcohol may be called resin a, that left undissolved resin b, and that preci- pitated at first by the potash resin c. 1 . The resin a is very analogous to the pinic acid from turpen- tine. It is soluble in alcohol, ether, and oil of turpentine. Naphtha only dissolves it partially ; but the portion undissolved possesses the same characters as the portion dissolved. It is easily soluble both in ammonia and in caustic potash. By an excess of the latter it is thrown down in the state of viscid resinate of potash. Most salts with an alkaline base produce the same etlect. The resinate of potash when dried is brown and brittle ; soluble in alcohol a; ' water, but insoluble in ether. The alkaline carbonates when boiled with this resin are decomposed. When the resinate of ammonia is boiled, the ammonia is disengaged, and the pure resin precipitates. This resin, by double decomposition with the salts of the earths and metallic oxides, forms compounds which are insoluble in alcohol and ether. The resinate of copper, formed by resin a of sandarach, is ' I'ogjjendorrs Amialen, vii. 311. f Tlienard, Traite de Cliimie, ill. 225. X Nicltoison's Juur. \. 24G. ^ Ibid. 2m M r .;, ,'i. 5 ' I m [ill RESINS. insoluble in ether, which distinf?uishes it from the pinate of copper, formed by the pinic acid from turpentine. 2. JResin b remains in the state of a viscid mass, when resin a has been separated from it. It retains a little alcohol, from which it may be freed by boiling it in water. It is a yellow resin, soluble in ether and absolute alcohol ; but insoluble in oil of turpentine and naphtha. The volatile oil from carum carvi dissolves it readily. It combines also with the bases, and forms salts. Its resinate of pot- ash is very soluble in water, but it is precipitated from its solution by an excess of potash, and by the salts having potash for a base. This resinate is oleaginous at the temperature of 212° ; but at the usual temperature of the air it is hard and brittle, and may easily be crumbled to powder between the fingers. When solid it dissolves slowly in cold, rapidly in boiling water. It is also soluble in alco- hol, but not in ether. When its aqueous solution is decomposed by an acid, the resin precipitates in a gelatinous state. By boiling it contracts, and becomes light and porous, but does not assume the aspect of a resin. The resinate of ammonia is easily formed, and is not decomposed though raised to the boiling point. The resinates of the earths and metallic oxides are powders, insoluble in water, alcohol, and ether. When chloride of gold is decomposed by resinate of potash, we ob- tain a red coloured resinate of gold. 3. Resin c is obtained by the following process : — Dissolve in boiling alcohol of 0*879 the resinate of potash preciintated from the alcoholic solution of sandarach. Precipitate this solution, while still boiling hot, by muriatic acid, and wash the white powder precipi- tated. It is a resin containing water, which may be driven off by heat. This resin does not fuse but at a pretty high temperature. It assumes a shade of brown, but does not undergo decomposition. Alcohol of 0'879 does not act on it ; but it dissolves in all propor- tions when digested in alcohol of 0*822, or stronger, and also in ether. Oils of turpentine, carvi, and naphtha have no action on it. This resin, while moist, dissolves readily in potash, but after being dried, it dissolves only slowly. The resinate of ])otash is precipi- tated in the state of a jelly, from its aqueous solution, both by an excess of alkali, and by the salts with an alkaline base. It preserves its gelatinous state even when boiled, and dissolves readily in water. After being dried, it is a light-brown resin, which loses its water without any other change wiicn heated to 536°. It becomes vis- cous in alcohol, but does not dissolve. When placed in contact with it, cold, it combines with a certain quantity of that liquid, and is di- vided into scales. In boiling water it swells like gum tragacanth, but very little of it is dissolved. If we now add a little alcohol, it becomes as soluble as at first. While this resin retains its water, it combines with ammonia, without altering- its form, and without dissolving. This resinate of ammonia is soluble in absolute alcohol, when assisted by heat, but on cooling it falls down again in flocks. We may boil this resin- ELEMI. 531 copper, iin a has :h it may iluble in itine and Badily. It te of pot- 3 solution )r a bjise. Dut at the nay easily b dissolves le in alco- jcomposed By boiling Lssume the ecomposed earths and and ether, ish, we ob- Dissolve in [id from the , while still ler precipi- •iven oif by miperature. omposition. all propor- and also in Lction on it. after being is precipi- both by an t preserves ilv in water. ;o's its water jccomes vis- itact with it, , and is di- tragacanth, e alcohol, it ammonia, s resinate ot l)y heat, but 1 this resin- n ate in water without depriving it of its ammonia ; but it is gra- dually volatilized when the resinate is exp(^3ed to the air. The earthy and metallic resinates of this resin are insoluble in water, alcohol, and ether. SECTION IV. — OF ELEMI. This resin is obtained by incisions from the amyris etemifera, a shrub which is a native of South America, and from the amyris ceylonica, or halsamodendron zeytanicmn, which, as the specific name implies, is a native of Ceylon. Incisions are made in the bark during dry weather, and the resinous juice which exudes is left to harden in the sun. It comes to this country in long roundish cakes wrapped in flag leaves. It is of a pale yellow colour, semitranspa- rent ; at first softish, but it hardens by keeping. Its smell is at first strong and fragrant, but it gradually diminishes. Neumann found that alcohol dissolved j^ths of this substance ; the remainder con- sisted chiefly of impurities, and was partly taken up by water. Both water and alcohol, when distilled with it, come over strongly im- pregnated with its flavour. Along with the water there comes over a fragrant volatile oil, which amounts to about ygth of the resin employed.* When heated, or rubbed with a pointed instrument in the dark, it becomes luminous. Sulphuric acid converts it into tannin, and nitric acid into a bitter tasted substance, which throws down the metallic salts, without altering a solution of gelatin. According to an analysis of Bonastre, elemi is composed of Volatile oil ...... . 12";!) Transparent resin, soluble in cold alcohol . GO'O Milk-white do., soluble in boiling alcohol . 24*0 Bitter substance ...... 2-0 Impurity ....... 1*5 loot The alcoholic solution of the transparent resin reddens vegetable blues. The milk-white resin dissolves in boiling alcohol, but when the solution is cooled slowly, it precipitates in crystals. It is colourless, in powder, and Insoluble in the alkalies. H. Rose analyzed this resin, and found its constituents — Carbon 83*05 or 10 atoms = 7'5 or per cent. 83*33 Hydrogen 11-28 or 8 atoms = 1 — — 11*11 5*67 or i atom = 0*5 — — .5*55 Oxvgen I00*00t 9*0 100*00 It has, therefore, the same constituents with rosin, but contains only half as much oxygen. It is not endowed with acid properties. This resin is sometimes used in varnishes. * Neumann's Chom. p. 296. + SchwoiggerV Jour, xxxvi, .366. \ Poggendorf? Annalen, xxxiii. 49. 532 IlESINS. :i ■! :■ f ' SECTION V. OF TACAMAHAC. There are two species of resin distinguished by this name. One comes from the Isle of Bourbon and Madairascar, and is extracted from the callophyllum inophyllum. It is yellow, translucent, adhe- sive, has an agreeable smell, and an acrid taste. It occurs but rarely in commerce. The other species is obtained from i\\ejagara octandra, and like- wise, it is supposed, from the populus halsamifera. It comes from America in large oblong masses wrapt in flag leaves. It is of a light-brown colour, very brittle, and easily melted when heated. When pure it has an aromatic smell between that of lavender and musk. When distilled along with water or alcohol, nothing comes over with these liquids.* It is but partially soluble in alcohol. Ether, on the other hand, and the fixed oils, dissolve it completely. The Bourbon species is completely soluble in alcohol. The acids act upon it nearly as upon the resins in general. The tannin formed from it by nitric acid precipitates metallic solutions; but not gelatin. SECTION VI.- -OF LAUDANUM, OR LAOANUM. This resin is obtained from the cystus creticus, a shrub which gro\vS in Syria and the Grecian Islands. The surface of this shrab is covered .vith a viscid juice, which, when concreted, forms ladanum. It is collected while moist by drawing over it a kind of rake with thongs fixed to it. From these thonffs it is afterwards scraped with a knife. It is always mixed with dust and sand, some- times in great abundance. The best is in dark-coloured masses, almost black, and very soft, having a fragrant odour and a bitterish taste. The impurities, even in the best kinds, amount to about ,[th. Water dissolves rather more than j'^th of the pure portion, and the matter taken up is said to possess gummy properties. When distilled with water, a small quantity of volatile oil rises. Alcohol likewise comes over impregnated with the taste and smell of labdanum.f SECTION VII. — OF BOTANY BAY RESIN. This resin is said to be the produce of the acarois resinife/a, a tree which grows abundantly in New Holland, especially near Bo- tany Bay. Specimens of it were brought to London about the year 1799, where it was tried as a medicine. Some account was given of it in Governor Philips' Voynge,X and in White's Journal of a Voyage to New South Wales ;§ but it is to Professor Lichtenstein that we are indebted for an account of its chemical properties. He obtained specimens from London, and published t\w result of his experiments in Crell's Journal.^ The resin exudes spontaneously from the trunk of the singular tree which yields it, especially if the bark be wounded, it is at first fluid, but becomes gradually solid when dried in the sun. Accord- * Neumann's Cliom. p. 295. f Ihid. p. 295. X Dunc.in's New Dispensary, p. CO. ^'i Appendix, p. •2\!'>. \\ 1799, ii. 242. BLACK POPLAR UESIN. 533 ne. One jxtracted nt, adhe- ccurs but and like- lines from It is of a n lieated. cnder and ing comes n alcohol, ompletely. The acids [lin formed lot gelatin. hrub which ice of this etcd, forms it a kind of afterwards sand, somc- ■ed masses, , a bitterish about fth. on, and the len distilled hoi likewise anum.t resinifeio, a lly near Bo- out the year it was given Journal of a Lichtenstein perties. He result of his the singular It is at first Accord- in. 05. 1790. ii. 24-2. ing to Governor Philips, it is collected usually in the soil which surrounc's the tree, having doubtless rundown spontaneously to the ground. It consists of pieces of various sizes of a yellow colour, unless when covered with a greenish-grey crust. It h firm, yet brittle ; and when pounded, does not stick to the mortar nor cake. In the mouth it is easily reduced to powder without sticking to the leeth. It communicates merely a slight sweetish astringent taste. When moderately heated, it melts ; on hot coals it burns to a coal, emitting a white smoke, which has a fragrant odour somewhat like storax. When thrown into the fire, it increases the flame like pitch. It communicates to water the flavour of storax, but is insoluble in that liquid. When digested in alcohol, f ds dissolve ; the remaining third consists of 1 part of extractive matter, soluble in water, and having an astringent taste ; and 2 parts of woody fibre and other impurities, perfectly tasteless and insoluble. The solution has a brown colour, and exhibits the appearance and the smell of a solution of benzoiu. Water throws it down unaltered. When distilled, the products were water, and empyreumatic oil, and charcoal ; but it gives no traces of any acid, alkali, or salt, not even when distilled with water. Twelve parts were boiled in a solution of pure soda in water. 2 parts of the resin were dissolved; the remaining 10 parts were floating on the solution, cohering together in clots. No crystals were obtained by evaporating part of the solution ; and when sul- phuric acid was (lro])ped into another portion, resin separated un- altered. When mixed with twice its weight of nitric acid, the resin swims unaltered on the surface ; but when heat is applied, a consi- derable efl'ervescence takes place. The digestion was continued till the efl'ervescence stopped, and the resin swam on the surface of the liquid collected together in clots. It was then separated by filtra- tion. It had lost yVth of its weight. The resin thus treated had acquired a bitterish taste, was no( o easily melted as before, and alcohol was capable of dissolving only one-half of it. The solution was brown, tasted like bitter almonds ; and when mixed with water, let fall a yellow resinous precipitate of a very bitter taste. The in- soluble portion mixed with ^ ''or, but formed a turbid liquid, which passed through the filter,. The nitric acid solution separated from the I esin by liltration was transparent ; its colour was yellow ; its taste bitter ; and it tinged substances dipped into it of a yellow colour. By evaporation it yielded oxalic acid, and deposited a yel- low earthy-like powder. Tins last substance was insoluble in water, and scarcely soluble in alcohol. Its taste was exquisitely bitter, like quassia. It mixed with the saliva, and readily stained the skin and paper yellow. The residuum continued bluer and yellow ; but yielded no precipitate with potash and nitrate of lime.* SECTION VIII. — OF BLACK POPLAR RESIN. In the year 1770, the black poplar was pointed out, in a German ' Lichtenstein, Crell's Jour. 1799, ii. '242. ■: ' B- 1. fM- r 'I.i Ii \^'^ i i H 11 Ik ' ft i* II 'M a (■ 1 Vql m 1 ''1 mn i ' V' h ■ I f:), If I. W ■ "^ I, 1 1 1' I 1 •. t ! 534 UKSINS. periodical work, as a tree from which abundtince of wax could be obtained. It was even said that a manufactory of candles, from the wax of this tree, had been established in Italy. This account hav- ing been revived in 1804, Schraeder was induced to make a set of experiments on the subject. He found, that when the buds of this tree are boiled in water and properly pressed, they yield about ^th of their weight of a yellowish-white substance, which possesses the properties of a resin, and resembles, according to him, the yellow resin of Botany Bay. When digested in water, a coloured solution is obtained, which reddens litmus paper, which becomes muddy by cooling, and which, when evaporated, deposits small crystals.* SECTION IX. — OF GUAIACUM. This resin is obtained from the guaiacum officinale, a tree which is a native of the West Indies, and yields a very hard heavy wood. The resin exudes spontaneously, and is also driven out artificially by beating one end of the wood in billets previously bored longitu- dinally ; the melted resin runs out at the extremity farthest from the fire. This substance has been used in medicine for a considera- ble time, having been originally recommended in the venereal disease. Nothing is known concerning its original introduction into Europe. Guaiacum is a solid resin. Its colour differs considerably, being partly brownish, partly reddish, and partly greenish ; and it always becomes green when left exposed to the light in the open air.f It has a certain degree of transparency, and breaks with a vitreous fracture. When pounded it emits a pleasant balsamic smell, but has scarcely any taste, although when swallowed it excites a burn- ing sensati*^ . in the throat. When Iieated it melts, and diffuses at the same tii; e a pretty strong fragrant odour. Its specific gravity is l-2289.t When guaiacum is digested in water a portion of it is dissolved, the water acquiring a greenish-brown colour and a sweetish taste. The liquid, when evaporated, leaves a brown substance, which pos- sesses the properties of extractive ; Wing soluble in hot water and alcohol, but scarcely in sulphuric ether, and forming precipitates with muriates of aluminu, tin, and silver. This extractive amounts to about nine parts in the hundred of guaiacum. § Alcohol dissolves guaiacum with facility, and forms a deep brown- coloured solution. Water renders this solution milky by separating the resin. Muriatic acid throws down the guaiacum of an ash- grey, and sulphuric acid of a pale-green colour. Acetic acid and the alkalies occasion no precipitate. Liquid chlorine throws it down of a fine pale-blue, which does not change when dried. Diluted nitric acid occasions no change at first ; but after some hours the liquid becomes green, then blue, and at last brown, and at that period a brown-coloured precipitate falls down. If water be mixed * SchrtedcT, Gelilcn's Jour. vl. .598. f WoUaston, Nicholson's Jour. viii. 294. t lirande, Thil. Matj. xxv. 105. ^ Ibid. could be Toni the int hav- a set of s of tliis bout ^th jsses the e yellow solution luddy by lis.* ■ee which .vy wood, rtificially I longitu- hest from !OTisidera- il disease. 3 Europe, jly, being it always air.t It a vitreous smell, but 3S a burn- dittuses at tic gravity dissolved, 3tish taste, which pos- water and irecipitates e amounts eep brown- separating of an ash- ic acid and Dws it down I. Diluted ! hours the and at that H" be mixed Jour. viii. 294. i. GUAIACUM. 535 with the liquid when it has assumed a green or a blue-colour, green and blue precipitates may be respectively obtained.* Sulphuiic ether does not act so powerfully on guaiacum as alco- hol. The solution oltainod by means of it exhibits the same pro- perties when treated with reagents as that in alcohol.f The alkaline solutions, both pure and in the state of carbonates, dissolve guaiacum with facility. 2 ounces of a saturated solution of potash dissolved about 65 grains of guaiacum ; the same quantity of ammonia only 25 grains ^ or guaiacum dissolves in about 15 parts of potash and 38 parts of ammonia. Nitric acid threw down from these solutions a brown precipitate, simibr to what is obtained when the alcoholic solution is mixed M'ith the same acid. Muriatic acid and diluted sulphuric acid throw down a flesh-coloured curdy preci- pitate, which in its properties approaches the nature of extractive.^ Most of the acids act upon guaiacum with considerable energy. Sulphuric acid dissolves it, and forms a deep-red liquid, which deposits while fresh a lilac-coloured precipitate when mixed with water. When heat is applied the guaiacum is charred. Nitric acid dissolves guaiacum completely without the assistance of heat, and with a strong effervescence. When the solution is eva- porated, it yields a very large quantity of oxalic acid.§ No arti- ficial tannin appears to be formed, but rather a substance possessing the properties of extractive. Diluted nitric acid converts guaiacum into a brown substance, similar to the precipitate obtained by nitric acid from the alcoholic solution of guaiacum. This brown matter possesses the properties of a resin. || Muriatic acid acts but slightly, as the guaiacum soon melts into a blackish mass, which is not acted upon.^ Guaiacum is rendered blue by various animal and vegetable sub- stances. It becomes blue, according to Tadei, when rubbed in the state of powder with gluten of wheat, or with the farina which it contains. Planche observed that when transverse slices of the fresh roots of certain plants are cut, and some drops of tincture of guaia- cum let fall on them, they become blue, even though the air have no access to them. This phenomenon was produced on the roots of the following plants : — Cochlearia armoracia Symphitum officinale Leontodon taraxacum Cichorjum intibus Eryngium campestre Iris germanica Nympha;a alba Solanum tuberosum Inula helenium Daucus carota Glycyrrhiza glabra Brassica napus Arctium lappa Colchicum autumnale Saponaria officinalis Fumaria officinalis Rumex acetosa Scorzinera hispanica * Brande, Phil. Mag. xxv. 106. f Ibid. p. 106. | Ibid. p. 109. § Hatchett, Second Series of Experiments on Artificial Tannin, Phil. Trans. 1806. II Brande, Phil. Mag. xxv, 107, H Ibid. :mall portion of the mix- ture. They are separated by digesting powdered gUviiacum in liquid ammonia, which dissolves the one and leaves the < ther. 1. The resin which is soluble in ammonia constitutes but a small portion of tho guaiacum. It dissolves in all proportions in ammonia. It is equally soluble in alcohol, and precipitates the alcoholic solu- tion of acetate of copper. 2. The resin insoluble in ammonia absorbs a considerable portion of that alkali during the digestion, and becomes viscid. But the compound formed requires more than GOOO times its weight of water to dissolve it. The resin may be separated by an acid from the ammonia. It possesses the characteis of guaiacum already de- scribed, as it constitutes tlio principal part of that substance. It dissolves in alcohol, but the solution is not precipitated by acetate of copper. It is very soluble in potash, and when boiled with the carbonate of that alkali, separates the carbonic acid from it. If we add, drop by drop, a solution of the resinate of potash into a solution of the protochloride of iron or mercury, a blue precipi- tate falls, consisting of a blue resin mixed with the respective chloride. Alcohol dissolves the blue resin, and leaves the resinate. When the alcohol i- driven off by evaporation, there remains a deep blue resin, which on fusion becomes brown, and -quite similar to guaiacum. The sulphuric and muriatic acids destroy the blue colour without dissolving the resin. Potash dissolves it and destroys the blue colour. When this oxide is disoxygenized it becomes brown ; and it would appear that the addition of oxygen gives it a similar colour. If we evaporate to dryness an alcoholic solution of the resin of guaiacum, and melt in a low heat the resin thus obtained, to drive off the whole of the alcohol, and then dissolve it in caustic potash, so as to saturate the alkali with the resin, and then drop very slowly this alkaline solution into a dilute solution of protochloride of gold, '^HHMHSHEm^. nUA(;ON S BLOOD. 537 ated to the blue produce rum tra- in eft'ect. le, when icture of does not the air. iposed of the inix- ,iacum in her. it a small ammonia, lolic solu- le portion But the iveitjht of acid from Iready de- itanee. It by acetate ;d with the I it. potash into ue precipi- respcctive le resinate. ains a deep ! similar to blue colour iestroys the mes brown ; , it a similar the resin of led, to drive ustic potash, P very slowly ride of ^^old, taking care not to precipitate all the gold, we obtain a blue-coloured precipitate, which becomes pulverulent when boiled, and assumes a violet colour when treated with nitric acid. This precipitate is a compound of peroxide of gold and the resin. Potash dissolves it, assuming a purple-red colour. It is insoluble in alcohol and ether, and is precipitated by alcohol from its aqueous solution. The resinate of potash may be used to obtain, by double decom- position, other resinates from the earthy and metallic salts. Guaiacum is a good deal employed in medicine. When given to the extent of half a scruple, it frequently acts as a sudorific. It is often adulterated with common rosin. To discover this fraud, we have only to dissolve the guaiacum in caustic potash. If the guaiacum be pure the solution is limpid, but muddy if rosin be pre- sent, as long as there is an excess of alkali ; because this excess precipitates the pinate and silvate of potash from the solution. SECTION X. — OF STORAX. This is the most fragrant of all the resins, and is obtained from the styrnx officinalis, a tree which grows in the Levant, and it is said also in Italy. Sometimes it is in the state of red tears ; and this is said to be the state in which it is obtained from the tree. But common storax is in large cakes ; brittle, but soft to the touch, and of a reddish-brown colour. This is more fragrant than the other sort, though it contains a considerable mixture of saw-dust. It dissolves in alcohol. When distilled with alcohol or with water, scarcely any oil is obtained. When distilled by the naked fire, it seems, from the experiments of Neumann, to yield the same pro- ducts as benzoin.* SECTION XI. — OF dragon's liLOOD. This is a brittle substance of a dark-red colour, which comes from the East Indies. There are two sorts of it ; one in small oval drops or tears of a fine deep red, which becomes crimson when the tears are reduced to powder ; the other is in larger masses, some of which are pale red, and others dark. It is probably obtained from differ- ent kinds of trees ; the calamus draco is said to furnish most of what comes from India. The draccena draco, and the pterocarpus draco are also said to turnish it. Dragon's blood is brittle and tasteless, and has no sensible smell. Water does not act upon it, but alcohol dissolves the greatest part, leaving a whitish-red substance, partially acted upon by water. The soluHon has a fine deep-red colour, which stains marble, and the stain penetrates the deeper the hotter the marble is. It dissolves likewise in oils, and gives them a deep-red colour also. When heated it melts, catches tiarae, and emits an acid fume similar to that of benzoic acid.f When d'gested with lime, a portion of it becomes soluble in water, and it acquires a balsamic odour. On * Neumann's Cheinistry, p. 290. f Lewis, Neumann's Chem. p. 'iDO. »r»*" 538 nESlNS. !l i?. iH U I 1 f I ■! ' f t 1 I adding muriatic acid to the solution, a red resinous substance is preci- pitated, and slight traces of benzoic acid only become perceptible.* Nitric acid acts u])on it with energy, changes it to a deep yellow, a portion of benzoic acid is sublimed, and a brown mass remains, soluble in water and possessing the properti(!s of artificial tannin.f When treated with sulphuric acid no perceptible portion of benzoic acid , sublimes ; but it is converted j)artly into artificial tannin, while a quantity of charcoal is evolved, amounting to 0*48 of the original dragon's blood em})loyed4 Herberger has analyzed dragon's blood, and has found it com- posed of Fixed oil .... 2-0 Red rcsin§ .... 90-7 Benzoic acid .... 3-0 Oxalate of lime ... l*G Phosphate of Ume ... 3"7 101-0|| According to INIclandi ', when dragon's blood is acidulated with sulphuric acid, that r throws it down from this solution with its properties a little altered. Nitric acid nuiy be distilled off it without converting it into artificial tannin. By this process }th of the dammara becomes soluble in water, while the remaining itli dissolve partially in alcohol, and completely in ether. Potash and ammonia, when boiled with this resin, combine with it. The resinate of potash is but little soluble in water, since, when treated with boiling water, jds of it renmin undissolved. VN'hen we dissolve dammara in oil of turpentine, and boil it with a solution of potash till all the oil of turj)entine is driven off, wc obtain a resinate of potash entirely soluble in water and in alcohol. Brandes analyzed dammara, and found it composed of A resin soluble in alcohol . . 83* 1 A resin insoluble in alcohol . 16*8 99-9 With a trace of jjum and succinic acid. Let us call the resin soluble in alcohol, resin a, and the other resin h. 1. Itcsin o, precipitated by water from its alcoholic solution, re- tains obstinately a portion of the alcohol. In that state it is soft, dark-brown, and transparent. It contains, at the same time, a little volatile oil, which gives it a smell similar to that of copaiva. The alcohol may be separated by boiling it in water, or by melting it in a ffentle heat. It is then hard. It dissolves in less than its weijjht of absolute alcohol. In alcohol of 0*855 it does not dissolve, except •by the assistance of heat. It dissolves in ether, oils of turpentine, and lavender, and in the fixed oils. Sulphuric acid and muriatic acid give it a red colour, and redden also its solutions ; but the resin is altered in its properties. Dilute phosphoric acid dissolves a little of it by the assistance of a boiling heat. Nitric acid darkens its colour and decomposes it. 2. Resin b, called also dammarin, is very little soluble in cold absolute alcohol. When dammara is digested in boiling absolute alcohol, and the solution allowed to cool, the resiii b is deposited. It is a snow-white powder, light and bulky. It is fusible, and burns with flame when held to a candle. It requires for dissolving it 1000 parts of cold absolute alcohol, and 40 or 50 times its weight of ether. Oil of turpentine dissolves half its weight of it. It dissolves also in the fixed oils by the assistance of heat. Acids scarcely act upon this resin, and it does not seem capable of combining with the caustic alkalies. lii >l^ I 1 1' Pi 'LI m H J 040 nESINS. ^ ■;.'■. I Apcordin*? to Liu-aims, wIhmi 2 pai'ts <»f dauimara arr ii,.itato(l with 2i parts of oil of turpentiiu; a varnish is fornuil, whi< h ariHwi-ra luui'h better for litliographic enjfraviiigs tlian onlinfi . mastic varnish, being transparent, more durable, and less c( loured.* SECTION XIII. — OF IlEHm OI' JALAP. This resin is obtained by digest) v tJie root of the convolvulus jalappa in Jilcohol, and inixinjj the alcoholie solution with water, and distillinj; olf the ahohol. It has a brownish-yellow colour and little lustre. It is ojjacpic, brittle, and has a bitter and acrid taste. When heated or rid)bed, it exhales the odour of jalap. It is very soluble in alcohol. The solution, digested with animal charcoal and liltered, is rendered nearly colourless. When it is now precipitated an(! nu'lted, it has a yellow colour. Ether disH(»lve8 about i^ijths of its weight of it. The portion dissolved reui.iins after the ether is evaporated in the state of a deep brown resin, which it is difficult to dry completely. It dissolves in caustic soda, and the solution is not precipitated by sulphuric acid. Hut the portion insoluble in ether is ])re(ij)itated when we saturate its solu- tion in soda with sulphuric acid. It is obvious, from this, that the resin of jalap consists of two resins. It dissolves cimipletely in acetic ether and acetic acid. But it is insoluble in the tixed and volatile oils. Ilerberger assures us thac the resui of jalaj) dissolved in alcohol, and mixed with an alcoholic solution of acetate of lead, gives a solu- tion of resinate of lead. The acid resin, vvhi(di, in this case, rombines with the oxide of lead, has not been examined. A great ■jart of the resin is not precipitated. The solution, freed from acetic acid, oxide of lead, and alcohol, gives a transparent colourless resin, very soluble in alcohol. Con- centrated acetic acid dissolves it completely with the assistance of heat. Sulphuric, nitric, phosphoric, and muriatic acids do not dis- solve it. Herberger has given it the name of jalappiii, and considers it as an alkaloid. But its alkaline proj)erties have not been suificiently established.f It is believed that scammony, the highest priced of the cathartic gum resins is sometimes adulterated by an admixture of the resin of jalap. M. Planche has pointed out a way by which this adul- teration may be detected.^ When scammony is triturated with milk in a mortar, an emulsion is formed, and the whole scammony is held suspended. But when the resin of jalap is treated in the same way, the particles are united into a solid mass. This is the case also with the resin of colystegia soldanella, used in France as a purgative. SECTION XIV. — OF BENZOIN. This substance is the produce of the stijrax hemoe, a tree which * Berzelius, Traite de Chiinie, v. 501. f Jour, de Pharm. xvii. 2"J7. % Ibid, xviii. 181. n a^ijitjitctl ■h andwera I , nuistic pa.* :mivolvulus vitlv water, colour ami iicr'ul taste. vith innui:il LMi it is now IV tlissolves oil roiuiiiis irowu resin, auslic soda, I. Hut the ate its solu- isists of two acetie acid. ifives d in alcohol, a solu- this case, d. A great and alcohol, [ohol. Con- I assistance of ,s do not dis- ilupjnn, and :ies have not Ithe cathartic of the resin ich this adul- fturated with jle scamraony •eated in the This is the France as a »EN/()IN. 541 prow- in Sumatra, &r., and which has hoen desrrihcd hy Mr Drvander.* Hcnzoin is obtained from this tree hy incision; u tree yielding 3 or 4 poundH. It is a solid brittle substance, sonietinics in the form of yellowihh-white tears joined together l>y a brown sub- stance, and sometimes in the torm of a l)rown substance not unlike common rosin. It has a very agreeable smell, which is increa^-d by heating the benzoin. It has little taste. Its specillc gravity is 1*U!)2. 'I'his sid)stanc(> has been used in medicine for ages, and various processes have been pointed oit by chemists for extracting benzoic acid from it. It was exaniined chemically a good many years ago by Mr IJrande.t and more lately by I'nverdorben, to whom wi; are in- debted for so much of ouf ' iwledge of resinous substances.^ "tfect on benzoin, but boiling water Cold water has very takes up a |)()rtion of Ik Alcohol dissolves it w 'n deep yellow solution inci- I by a gentle heat, and forms a K reddish-brown. When this solu- tion is diluted with water, ilie benzoin precipitates in the form of a white j)o\vder. It is precipitated also by muriatic and acetic aci^ C'-Vr 7 Hiotographic Sciences Corporation 23 WEST MAIN STREET WEBSTER, N.Y. 14580 (716) 872-4503 '•I) d y. s il 542 RESINS. days' exposure to the air. Ammonia likewise dissolves benzoin sparingly.* Unverdorben subjected benzoin to an analysis, and found it to contain, besides benzoic acid, and a little volatile oil, three different resins, which he distinguishes from each other, by naming them resins a, h, and c. If we reduce benzoin to powder, and boil it in an excess of car- bonate of potash, the benzoic acid and a resin are dissolved, and may be precipitated by adding muriatic acid to the solution. When we boil this precipitate in water, the benzoic acid, and a little ex- tractive are dissolved, and the resin remains, amounting only to j^jyth of the benzoin employed. This is resin c. The principal part of the benzoin does not dissolve in the car- bonate of potash. A light brown-coloured matter remains. When it is digested in ether one resin is dissolved, and the other remains. The first part of these is resin a ; the second, resin h. 1. Resin a remains when the ethereal solution is evaporated to dryness. It is very soluble in alcohol and oil of carvi ; but insoluble in naphtha. It does not decompose acetate of copper, but it dis- solves readily in potash, and an excess of that alkali does not pre- cipitate it from its solution. Ammonia does not dissolve it. Its combinations with earths and metallic oxides are insoluble in ether. 2. Resin b, when washed with ether and dried, has a brown colour. It is soluble in alcohol, but insoluble in the volatile oils. Caustic ammonia does not dissolve it ; but caustic potash dissolves it with facility. An excess of alkali throws down the resinate of potash formed. When resins a and b are precipitated by an acid from their solu- tion in potash, and exposed to the air while still moist, they are converted into resin c. When they are distilled per se, they give out a volatile oil, slightly empyreumatic, which, like the oil of bitter almonds, is converted by exposure to the air into benzoic acid. 3. Resin c has a deep-brown colour. It is soluble in alcohol of 0*875, and in more concentrated alcohol. It is little soluble in ether and volatile oils, and insoluble in naphtha. It possesses weak acid properties : it does not decompose acetate of copper, but it preci- pitates acetate of lead. Carbonate of potash dissolves it slowly. The resinate of potash is soluble in absolute alcohol, but insoluble in ether and oil of turpentine. Its solution in water is precipitated by sal ammoniac. The resinate of copper, obtained by double decomposition, is insoluble in ether and oil of turpentine. M. Dulong d'Astafort has observed that resin of benzoin strikes a fine red colour with sulphuric acid.f This observation had been made long before by Mr Hatchett. SECTION XV OF ANIMfe. This resin is obtained from the hymencBU courbaril, or locust tree, I * Brando, Nicholson's Jour. x. 8G. f Jour, do Pharrtiacie, xii. 33. COPAL. 043 which is a native of Cayenne. Anim6 resembles copal very much in its appearance ; but it is easily soluble in alcohol, which copal is not : this readily distinguishes them. It is said to be very frequently employed in the making of varnishes. Alcohol dissolves it com- pletely. Water, according to the experiments of Neumann, dis- solves about jjjth of it ; and when the decoction is evaporated, it leaves an unctuous mass, which makes the fingers oily. Alcohol distilled over it acquires both the smell and taste of anime. Water distilled from it shows on its surface a small quantity of volatile oil.* When anime is digested in cold alcohol, a portion remains undis- solved. This residue dissolves in boiling alcohol, and crystallizes as the solution cools, or by evaporation if the solution was not saturated. These crystals are colourless, and may be sublimed. Bonastre gives them the name of subresin, but their characters have not been investigated. Anim^ contains a minute portion of volatile oil, to which it is indebted for its agreeable odour. SECTION XVI. — OF COPAL. This resin, by far the most important of the whole class, flows spontaneously from the rhus copalinum. and elceocarpus copaliferus. The first of these trees grows in America, the second in the East Indies. A third species is said to exist on the coast of Guinea, especially near rivers, and it is collected from the sand on the shore. From Dr Roxburgh's account, it appears that the East Indian tree, valeriea indica, yields a resin possessing intermediate properties between copal and amber .f Copal is a beautiful white reshious substance, with a slight tint of brown. It is sometimes opaque, and sometimes almost perfectly transparent. When heated it melts like other resins ; but it diff'ers from them in not being soluble in alcohol, nor in oil of turpentine without peculiar management. Neither does it dissolve in the fixed oils with the same ease as the other resins. It resembles gum anime a little in appearance; but is easily distinguished by the solubility of this last in alcohol, and by its being brittle between the teeth, whereas anime softens in the mouth.:}: The specific gravity of copal varies, according to Brisson, from 1'045 to 1*139. I found it r069. Mr Hatchett found it soluble in alkalies and nitric acid with the usual phenomena ; so that, in this respect, it agrees with the other resins. The solution of copal in alkalies he found indeed opalescent, but it is nevertheless permanent. It deserves attention, that he found rosin, when dissolved in nitric acid, and then thrown down by an alkali, to acquire a smell resembling that of copal. f 1 • Neumann's Chera, p. 297. f Nicholson's Jour, xxvii. 72. It is stated in the Journal de Pharmacic (xxii. 522), that the true copal of Madagascar conies from the hymencea verrucosa ; the copal of India from the trachylobium hornemannianum of Hayne, and the copal of Brazil from the trachylobium martianum of Hayne. X Lewis, Neumann's Chem. p. 299. [ ul I. ! t' i 544 RESINS. When copal is dissolved in any volatile liquid, and spread thin upon wood, metal, paper, &c., so that the volatile menstruum may evaporate, the copal remains perfectly transparent, and forms one of the most beautiful and perfect varnishes that can well be con- ceived. The varnish thus formed is called copal varnish, from the chief ingredient in it. This varnish was first discovered in France, and was long known by the name of verms martin. The method of preparing it is concealed ; but different processes for dissolving copal in volatile menstrua have been from time to time made public. The following are the most remarkable of these : — When copal is kept melted till a sour smelling aromatic odour has ceased to proceed from it, and then mixed with an equal quantity of linseed oil, which has been deprived of all colour by exposure to the sun, it unites with the oil, and forms a varnish which must be dried in the sun.* I have been informed by a very ingenious japan manufacturer in Glasgow, that the copal varnish used by the English japanners is made as follows: — Four parts by weight of copal in powder are put into a glass matrass and melted. The liquid is kept boiling till the fumes, condensed upon the point of the tube thrust into a matrass, drop to the bottom of the liquid without occasioning any hissing noise, as water does. This is a proof that all the water is dissipated, and that the copal has been long enough melted. One part of boiling-hot linseed oil (previously boiled in a retort without any litharge) is now poured into it, and well mixed. The matrass is then taken off the fire, and the liquid, while still hot, is mixed with about its own weight of oil of turpentine. The varnish thus made is transparent, but it has a tint of yellow, which the japanners endeavour to conceal by giving the white ground on which they apply it a shade of blue. It is with this varnisii that the dial plates of clocks are covered after having been painted white. When copal is treated with oil of turpentine '.- ,ise vessels, the vapour, being prevented from escaping, exerts ^ . eater pressure, and the heat rises above the boiling point. This additional heat is said to enable the oil to dissolve the copal. The solution, mixed with a little poppy oil, forms a varnls'S which is distuiguished from the vernis martin merely in having a very rlight tinge of brown.f The method of dissolving copal in oil of turpentine, published by Mr Sheldrake, seems to depend upon the same principle with the last solution. On 2 ounces of copal, broken into small pieces, is poui*ed a mixture of 4 ounces of ammonia with a pint of oil of turpentine. The whole is kept boiling very gently, so that the bubbles may be counted as they rise. If the heat be allowed to diminish, or if it be raised too high, the process stops, and cannot be again resumed. The matrass, in which the mixture is boiled, is stopped with a cork, secured in its place by a brass wire, and per- forated by a pin. When the copal is nearly dissolved, the process Dr Black's Lectures, ii. 359. t Ibid. COPAL. 545 read thin uum may Forms one 1 be con- , from the in France, method of ving copal lie. The odour has [quantity of mre to the 3t be dried facturer in ersismade ; put into a the fumes, drop to the je, as water nd that the -hot linseed now poured ;he fire, and eight of oil aut it has a 1 by giving It is with fter having vessels, the !r pressure, onal heat is ition, mixed uished from f brown.t )ublished by lie with the ill pieces, is nt of oil of so that the allowed to and cannot l-e is boiled, ire, and per- the process is stopped, and the whole allowed to cool before uncorking the matrass. This varnish has a deep colour ; but when spread thin and allowed to dry, it becomes colourless. Its defect is the difficulty with which it dries. This defect Mr Sheldrake remedies by throw- ing the solution into its own weight of nut oil, rendered drying by white lead, and agitating till the turpentine is separated. To dissolve copal in alcohol, Mr Sheldrake dissolves half an ounce of camphor in a pint of that liquid, and pours the solution on four ounces of copal. The matrass is placed in a sand bath, and the process is conducted exactly as the one last described. The solution thus formed contains a great deal of copal, and forms a varnish which is perfectly colourless; but considerable heat is necessary to drive off the camphor. Mr Sheldrake has favoured the public with another and easier method of dissolving copal. This method is as follows : — " Provide a strong vessel made of tin or other metal ; it should be shaped like a wine bottle, and capable of holding two quarts ; it will be convenient to have a handle strongly riveted to the neck ; the neck should be long and have a cork fitted to the mouth, but a notch or small hole should be made in the cork, that when the spirit is expanded by heat, a small portion may force its way through the hole, and thus prevent the vessel from bursting. " Dissolve half an ounce of camphor in a quart of spirit of tur- pentine, and put it into the vessel ; take a piece of copal the size of a large walnut, reduce it to a coarse powder or very small pieces ; put them into the tin bottle, ftisten the cork down with a wire, and set it as quick as possible upon a fire so brisk as to make the spirit boil almost immediately ; then keep it boiling very gently for about an hour, when so much of the copal will be dissolved as will make a very good varnish ; or, if the operation has been properly begun, but enough of copal has not been dissolved, it may be again put on the fire, and by boiling it slowly for a longer time, it may be at last brought to the consistence depired."* Van Mons relates another process much simpler than any of the above, which he says was taught him by Mr Demmenie, a Dutch artist. It consists in exposing copal to the action of the steam of alcohol. A long-necked matrass is filled ^th full of strong alcohol, and a piece of copal is suspended above the surface of the liquid at some little distance ; the top of the matrass is covered with a con- densator ; the alcohol is kept boiling : the copal softens, and drops down into the alcohol like oil. When these drops no longer dissolve, the process must be stopped. The solution thus obtained is per- fectly colourless. Copal may be dissolved in oil of turpentine by the same process.f The following method of making copal varnish has been recom- mended by Professor Lenormand: — Drop upon the pieces of copal pure essential oil of rosemary. Those pieces that are softened by I a ! • Nicholson's Jour. ix. 157. f Ibi'l. xxiv. 67. 2 N ■ I i • : * 546 ^im RESINS. the oil are fit for the purpose, the others not. Reduce them to a fine powder, put this powder into a glass vessel not thicker than a finger breadth, pour oil of rosemary over it, and stir it about with a glass rod. In a short time the whole is converted into a very thick liquid. Pour alcohol on this liquid by little at a time, incorporating it, by gently agitating the vessel, till it is of the requisite thinness for use.* Unverdorben assures us that copal dissolves when we digest, for 24 hours, 1 part of it in 1^ parts of alcohol, because the portion of copal which is insoluble in alcohol dissolves in a very concentrated solution of the soluble portion. Naphtha dissolves the 100th part of its weight of this resin, and oil of turpentine dissolves rather more. Unverdorben has analyzed the African copal, and has extracted from it no fewer than five different resins. His method of analysis was this : — 1. He reduced the copal to powder, and digested it in alcohol of 0*879, till every thing soluble was taken up. 2. The residue was digested in absolute alcohol, till every thing soluble in that liquid was taken up. 3. The residual matter was treated with half its weight of hydrate of potash dissolved in alcohol of 0*855. 4. What remained was a compound of resin and potash, which when digested in alcohol of 0*967 left a new residue. Thus the sub- stances extracted from the copal were distributed in four divisions. 1st Division. The solution in alcohol of 0*879, contained two resins. They are precipitated in combination with oxide of copper, by pouring an acoholic solution of acetate of copper into the liquid containing them. When the precipitate is digested in ether the resinate of copper containing resin a dissolves, while the resinate containing resin b remains undissolved. If we dissolve them in alcohol acidulated with muriatic acid, and add water to the respec- tive solutions, the two resins fall freed from the oxide of copper. (1.) Resin a is colourless and soft, owing to the presence of a small quantity of volatile oil, which is easily disengaged by boiling the resin with water, or by cautiously fusing it. It is then hard. It melts at 212° ; and dissolves in all proportions in alcohol of 0*867. When precipitated from that solution by water, it has the fluidity of a fixed oil, and contains combined alcohol, which can only be se- parated by long boiling in water or by fusion. This resin possesses the properties of an acid, and forms salts. The resinate of potash is colourless. By an excess of caustic potash it is precipitated in the state of a viscid mass from the concentrated solution, and in a gelatinous or mucous state from a diluted solution. It dissolves slowly in cold water, rapidly in hot water. The resin dissolves in ammonia, forming a mucilaginous liquid, which may be boiled for a little without allowing the whole of the resin to precipitate. The resinates of the earths and metallic oxides may be formed by double decomposition. They are insolu- ble in alcohol ; but most of them are soluble in ether. • Jour, do Cliim. iii. 218. COPAL. 547 to a fine a finger h a glass jk liquid, ng it, by , for use.* ligeat, for portion of iccntrated OOtli part res rather extracted jf analysis ested it in . 2. The ; soluble in reated with 1 of 0-855. vhich when IS the sub- ir divisions, ntained two e of copper, o the Uquid n ether the ,he resinate ve thera in the respec- f copper. resence of a d by boiling then hard. lol of 0-867. le fluidity of only be se- forms salts, austic potash concentrated ted solution. inous liquid, whole of the and metallic are insolu- (2.) Resin b has a striking resemblance to the preceding resin. But it does not melt nt 212*^, and its compounds with the metallic oxides are insoluble in ether. It does not dissolve in alcohol of 0-879, but absorbs a certain quantity of it, and becomes viscid and white. When boiled in water it loses the alcohol absorbed, and remains in the state of a coherent, porous, brittle mass. It is soluble in absolute alcohol and in ether, but does not dissolve in oil of turpentine and the fixed oils. It dissolves readily in caustic potash. An excess of alkali precipitates the resinate of potash in a viscid mass. The resinate of potash is soluble in water and in alcohol, hut insoluble in ether and oils. Ammonia dissolves this resin into a thick but transparent liquid. When boiled it becomes muddy, but the resinate is not precipitated. By spontaneous evaporation we obtain the resinate of ammonia in a transparent state. The resinates of earths and metallic oxides may be obtained by double decomposition. They constitute viscid masses insoluble in alcohol and in ether. When we boil a mixture of resinate of potash and protochloride of gold, we obtain a red- coloured resinate of gold, which dissolves in potash or ammonia, and is thrown down unaltered from these solutions by an acid. 2rf Division. The residue left by alcohol of 0-879, is a viscid mass. When it is boiled in absolute alcohol, a great deal of resins a and 6, and at the same time another resin, which we may call resin c, are dissolved. If we mix the alcoholic solution with a con- centrated alcoholic solution of potash, adding this solution in excess, a precipitate falls, consisting chiefly of resin c, combined with potash ; though it contains a little of resin b. To separate these two resins we dissolve the resinate of potash in boiling water, and precipitate the liquid while hot by sulphuric acid ; wash the precipitate, dry it and treat it with absolute alcohol. The resin b will be dissolved, and resin c left. 3c? Division. The viscid residue insoluble in absolute alcohol is boiled with half its weight of hydrate of potash dissolved in alcohol of 0-857. Only the resinate of potash formed by resin c is dissolved. If we saturate the boiling hot solution with sulphuric acid, the resin c precipitates in fine powder. (3.) Resin c possesses the following properties : — It is a powder and cannot be melted without, at the same time, undergoing decom- position. When heated in a retort it begins to swell at 662", and begins to be charred at the same time. It seems to contain no combined water. It does not dissolve in absolute alcohol, but it absorbs a quantity of it and becomes viscid. It is very soluble in ether and oil of cajeput ; but it does not dissolve in oil of turpentine unless it has been previously melted. Its resinate of potash is viscid when in the state of a concentrated solution. When dried it is a transparent gummy mass, which does not dissolve in water whether cold or hot. But it dissolves in water to which a little alcohol has been added, and continues dissolved though the alcohol Ifli 548 RESINS. ,1 ' [( |! be driven off' by evaporation. A very slight excess of alkali throws down the resinate in a gelatinous state ; but a great excess is requisite to throw it down from its alcoholic solution. This resin does not dissolve in ammonia, unless we add a little alcohol to the ammoniacal liquid. And we may evaporate away the alcohol and excess of ammonia without rendering the solution muddy. When sal ammoniac is added to a solution of resinate of potash, or resinate of ammonia, the resin is precipitated in a gelatinous state. The resinates of the earths and metallic oxides are gelatinous and insoluble in water, alcohol, ether, and oils. But they are slightly soluble in an ethereal solution of resin c. 4/fi Division. The residue of copal from the preceding division, is diijested in boiling hot alcohol of the specific gravity of 0*967. It leaves a residue amounting to about 8 per cent, of the copal employed. The weak alcohol dissolves a resinate of potash insoluble in stronger alcohol, and when the solution is mixed with muriatic acid it coagulates into a jelly, which deposits, on boiling, a resin in powder, which may bo collected on a filter, washed and dried. It constitutes resin d. (4.) Resin c? is a white farinaceous powder, which cannot be melted. At 212° it gives out a little water ; at 572° it gives out a great deal and concretes together. At a higher temperature it swells and is charred without melting. It is completely insoluble in absolute alcohol, ether, and oil of turpentine ; nor is it altered by any of these liquids. But after being softened by heat it dissolves in oil of turpentine. It is insol- uble in an aqueous solution of caustic potash, but it is transformed into resinate of potash, which is insoluble iu boiling water, but solu- ble in alcohol of 0-9()7, and precipitated from that solution in a gelatinous state, both by water and alcohol. The alcohol may be driven off from the solution in the weak spirit, without the resinate precipitating. By evaporation it becomes thick and gelatinous, and at last dries into a matter like gum, insoluble in water, and in alcohol stronger than 0'967. Pure resin d is not acted on by ammonia ; but when it is mixed with other resins it may be dissolved along with them in the am- moniacal liquor. Sal ammoniac poured into a solution of resinate of potash, throws down the resin in a gelatinous state, and free fi'om ammonia. The compounds of this resin with earths and metallic oxides, obtained by double decomposition, are gelatinous while moist, and insoluble in alcohol, ether, and oils. (5.) Resin e. The residue insoluble in spirits of the specific gravity 0*967 is gelatinous, and consists of a resin quite different from the preceding, which may be called resin e. While drying it agglutinates into a compact, infusible mass, which when heated gives out a good deal of water. It is insoluble in alcohol, ether, and oils, and neither combines with acids nor bases. It is therefore a neutral resin. . From the preceding analysis we see that when copal is treated n ili throws I requisite (1 a little 1 away the on muddy, potash, or lous state, tinons and re slightly [g division, I of 0-967. the copal i\\ insoluhle th muriatic , a resin in L dried. It , cannot be nrives out a iperature it , and oil of But after It is insol- transformed ;er, but solu- olution in a ohol may be the resinate atinous, and ater, and in n it is mixed in the am- n of resinate ite, and free earths and ) gelatinous the specific luite different hile drying it when heated lol, ether, and is therefore a )al is treated COPAL. 549 with boiling caustic potash, the portion dissolved consists of re»i/i« a and b, while all the other resins are in the coagulated portion. Unverdorben has observed, that, when resins d and e are kept in a phial, not tilled, under absolute alcohol, especially if a little ether be added, they absorb oxygen, and are gradually converted into resins a, b, and c. So that after a month resins d and e are no longer to be found. Copal in powder gradually undergoes a similar change. Probably as the copal flows from the trees that yield it, only resins d and e arc contained in it, and resins a, b, and c, are gradually formed by the action of the air. Unverdorben has also analyzed copal which has been fused. When we heat copal till it is liquid, and dissolves in oil of turpentine, it gives a very volatile oil, and a moderately volatile oil, intermediate between a volatile and empyreumatic oil. Towards the end of the distillation, resinous matter passes over. Fused copal still contains resins a and b, but the other resins are altered and we find in their place resins which are soluble in oil of turpentine. Alcohol of 0*879 extracts from fused copal the resins a and b. Absolute alcohol, being boiled in the residue, does not dissolve it completely. The liquid becomes muddy during the cooling, and deposits a viscid resin, which retains a little alcohol, and dissolves readily in ether and oil of turpentine. It is a moderately-acid resin. The alcohol becomes clear and cold, contains in solution the greater part of the melted copal, and leaves when evaporated resin c of melted copal. It possesses the following properties : — It is very soluble in alcohol of the specific gravity 0*832, and in absolute alcohol, also in oil of turpentine and the fixed oils. Com- bined with half its weight of alcohol, it has the appearance of an oil at the temperature of 185°, but at the ordinary temperature of the atmosphere it is a solid friable resin. Heat drives ofl^" the alcohol and leaves pure resin. It combines easily with potash. The resinate of potash is insoluble in alkaline water, but dissolves slowly in cold water, and more rapidly in boiling water It dis- solves also in alcohol, but is insoluble in ether. When Iry it resembles gum. With the earths and alkalies it forms combinations which concrete at 212°, and are not soluble in ether or in oils. The portion of melted copal insoluble in absolute alcohol may be called resin d. It possesses some of the properties of the resin d of unmelted copal. It is hard and brilliant, and not viscid at 212°. It is very soluble in ether, oil of turpentine, and the fixed oils. With boiling alcohol it forms a viscid compound, insoluble in alcohol, brittle when cold, and letting go the alcohol when heated. Potash and ammonia combine with this resin without dissolving it. Alco- holic water dissolves the resinate of potash, and the solution con- tinues after all the alcohol is driven off. This resinate is but little soluble in absolute alcohol, and the small quantity dissolved by boil- ing precipitates when the alcohol cools. This property of resin d enables us to get it free from all mixture of resin c. For when a mixture of the two resinates of potash is treated with absolute alco- 550 nusiNS. I : I a li ; li hol, all the resinate of c dissolves, while the resinate of d remains. When we pour a dilute acid on the resinate of potash, the resin d separates in the form of a jelly. This resin forms with earths and metallic oxides pulverulent compounds, which are insoluble in alco- hol and ether. SECTION XVII. — OF IIIGIIOATE RESIN. This substance was du^ up at Ilighgatc, near London, during the attempt, in 1813, to run a tunnel through the hill. It was in small amorphous masses of different sizes. Colour a muddy yellow- ish light-brown. Scmitransparcnt. Lustre resinous, and surface smooth, as if it had been long agitated in water. It was less easily broken than common rosin, but nuich more easily than copal. Softer than copnl. Has a resinous and aromatic smell, especially when heated. When heated it melts, and may be rendered as liquid as water, ithout altering its colour. When in lumps it is insoluble in water, alcohol, potash ley, acetic acid ; but ether renders it opaque and white, and quite tender. It loses its cohesion and crumbles into powder upon the least pressure between the fingers. The ether at the same time dissolves a portion, which it deposits when mixed with water. Nitric acid partly dissolves and partly converts it into a red- coloured substance. Water throws down the dissolved portion in the state of bitter-tasted white flocks. Sulphuric acid readily chars it when assisted by heat. When in a state of a fine powder, alco- hol dissolves a small portion of it. It is insoluble in potash ley.* SECTION XVIII. — OF LAC. This important resin is deposited in different species of trees in the East Indies, namely, they?cM« indica,ficus religiosOy and rham- nus jujuha. It flows out in the state of a milky liquid, in conse- quence of the puncture of a small insect, the coccus ficus, on the branches of these trees, made by the insect in order to deposit its ova. It has been imported into Europe, and extensively used from time immemorial ; but it is only of late years that correct informa- tion concerning it has been obtained. For what relates to the natural history of the insect, and the mode of forming the lac, we are indebted to Mr Ker,t Mr Saunders,t and Dr Roxburgh.§ Though very often employed in the arts, it was neglected by chemists. Geoffrey, junior, indeed, published a dissertation on it, but it con- tains few chemical experi nents. He merely subjected it to distilla- tion, and obtained products which he thought similar to those given by wax in the same circumstances.! This led him to consider it as a species of wax, an opinion followed by Neumann ;*| but Junker,** and most of the subsequent chemical writers, place it among the * Annals of Philosophy, ii. 9. f Phil. Trans. 1781, p. 376. X Phil. Trans. 1789, p. 107. § Ibid. 1791, p. 228. II Mem. Par. 1714, p. 121 ; and Marline's translations of the Mcniuires of the Fruncli Acadt-niy, v. 4. H Chemistry, p. 334. ** Conspectus Chemitc, ii. 70. LAC. 551 rcdins. Mr Hatchott has examined it with his usual address, and ascertained its coinnosition and properties.* A very important analysis of it was published by Unverdorben in 1828.t Wo are in- debted also to ik'rzeliiH for some experiments on it. There are varioua kinds of lac distinguished in commerce. Stick lac is the subatanco in its natural state, encrusting small twigs. When broken off and boiled in water it loses its red colour, and is called seed Inc. When molted and reduced to the state of a thin crust, it is called shell lac. Stick lac is of a deep red colour, and yields to water a substance which is used as a red dye. The other two varieties are brown. Water dissolves the greatest part of the colouring matter of lac, which varies from 15 to ^ per cent. Alcohol dissolves the greatest part of the resin, which constitutes the chief ingredient in the com- position of lac. Ether acts more feebly. Sulphuric acid dissolves and gradually chars lac ; nitric acid dissolves, and then produces the same changes on it as on other resinous bodies. Muriatic and acetic acids likewise act as solvents. A solution of borax in water readily dissolves lac. The best proportions are 20 grains of borax, 100 grains of lac, and 4 ounces of water. This solution, mixed with lamp black, constitutes Indian ink ; and may indeed be em- ployed for many of the purposes of varnish. The fixed alkalies readily dissolve lac, but not the volatile. When placed on a hot iron it melts, and emits a thick smoke with an odour rather pleasant, leaving a spongy coal. When distilled, it yields water slightly acidulous, and a thick butyraceous oil. The gases emitted are a mixture of carbonic acid and carburetted hydrogen. Stick lac yields also some carbonate of ammonia ; but the other two varieties none. The following table exhibits the constituents of the different varieties of lac, according to the analysis of Mr Hatchett : — Stick Lao. Seed Lae. Shell Lac Resin . . 68 88'5 90-9 Colouring matter . 10 2-5 0-5 Wax . . 6 4-5 40 Gluten . . 5-5 2-0 2*8 Foreign bodies . 6-5 .—. Loss . 4'5 2-5 1-8 100-5 100-0 100-0 The resin is less brittle than those bodies usually are. The colouring matter possesses the properties of extractive ; the wax is analogous to myrtle wax, and the gluten closely resembles the glu- ten of wheat.J Dr John published a set of observations on st'ck lac in 1810, and drew, as a conclusion, that it consists of three distinct substances, * Analytical Experiments on Lac, Phil. Trans. 1804. t Poggcnilorrs Aunalen, xiv. 116. % Hatchclt, Phil. Trans. 1804. 552 nRNINS. VIZ., a colouring matter, a peculiar body to which he gave the name of Inccin, and resin.* In the year 181(3, a very elaborate analysis of stick lac appcurcMl by the same chemist. According to him, 12U grains of stick luu are composed of the following substances : — liesin, insoluble in ether Laccin Cochenillin . Extractive . Yellow extract Laccic acid . Cochcnil coloured coverings of insects Waxy tallow Laccate of potash Sulphate oi potauli t Muriate of potusli Phosphate of lime A salt of iron Earthy mutter Loss 80 •20 4-5 3 0-5 0'75 f insects 25 • • 2 1-25 0-75 4-75 •It 120-00 The iaccin was the matter that remained after the lac had been repeatedly digested in alcohol and water, till nothing further could be removed. It is distinguished by the following characters : — It is hard and brittle, lias a yellow colour, and a certain degree of transparency. It is insoluble in cold water ; but in hot water, though it docs not dissolve, it becomes soft. In cold alcohol it softens, increases in bulk, and acquires a slippery feel. Even hot alcohol is unable to dissolve it. In ether and essential oils it swells a little, and becomes quite transparent, but does not dissolve. It dissolves very readily in potash ley, and the solution has a light-brown colour. Muriatic acid renders the solution milky, and the laccin slowly precipitates. Concentrated sulphuric acid dis- solves it very rapidly ; the solution has an amethyst colour, and be- comes muddy when mixed with water. When long boiled with water, containing from y\rth to ^th of its weight of sulphuric acid, only a small portion of it is dissolved. This portion is obtained in the state of a yellowish gum, when the acid is separated by means of lime, and the solution evaporated. This property distinguishes it readily from cerasin. Concentrated nitric acid dissolves it slowly when assisted by heat. The bolution is clear, and has a yellow colour, without any bitter taste. It gradually deposits some crys- tals of oxalic acid. Diluted nitric acid has no efi'cct on it either cold or hot. When heated, laccin gives out an aromatic odour, and becomes soft. It does not melt, but is gradually charred. When distilled, it gives out w ater, an acid, which, when saturated with soda, throws * Chcmischc Untcrsuchtingcn, i. 52. LAC. 553 e name pjieared tick luo ■.*•. \5 75 75 00 had been tlicr could ;er8 : — ftin degree hot water, alcohol it Even hot 8 it swells olve. tion has a milky, and acid dis- ur, and be- with water, icid, only a ned in the )y means of ingnishes it es it slowly lis a yellow some crys- on it either nni- down muriate of iron white, and a yellow and brown oil. No monia can be detected in the products of the dintillation.* But the analyoia of Unverdorbun deserves peculiar attention. He had made resinous bodies his particular study, and was able, therefore, to detect its various constituents with more address than his predecessors. IIo found in lac the following substances : — 1. A resin 8ohd)le in alcohol and ether, which may be called resin a of lac. 2. A resin soluble in alcohol, but insoluble in ether, renin h. 3. A resinous-looking substance, a little soluble in cold alcohol, resin e, 4. A crystaliizable resin, resin c. 5, A resin soluble in alcohol and ether, but insoluble in naphtha and uncrystallizabic, resin d. (i. Fat of coccis not saponified, together with some oleic and niargaric acid. 7. Wax. 8. iLac'ctn of John. This substance is not found in shell lac. 9. A red colour i»g matter. His mode of analysis was the following : — I. If wo digest purified lac in boiling alcohol of 0*879, till every thing soluble is taken up, and filter the solution while hot, it deposits, on cooling, a gelatinous matter, amounting lo about 8 per cent, of the lac employed. This is resin c. The alcohol leaves undissolved about 8 per cent, of the lac. H. The filtered alcohol solution is mixed with its own weight of water, and the alcohol being distilled otl', the residue is evaporated to dryness. The resin which remains is digested in water till every thing soluble in that liquid is taken up. A substance is dissolved containing resin a. From this solution the reain is precipitated by phosphoric acid. ( I .) Itesin a of lac possesses the following properties : — It is brown, easily melted, soluble in alcohol of 0*879, ami in ether. But this last liquid does not dissolve it completely. It leaves a portion (doubtless a peculiar resin) soluble in alcohol of 0*879, and in caustic potash. The ethereal solution when evaporated leaves resin a in a state of purity. It dissolves in caustic potash, which assumes a violet colour. The acetates of copper and lead precipitate its solution in alcohol. The resinates of copper and lead collect into a mass in boiling water, and are neither soluble in alcohol nor ether. Unverdorben informs us that rcsinate a of potash is decomposed by boiling, in such a manner that ^d of the resin is converted into oleic and raargaric acid. Lac does not contain more than half a per cent, of resiti a. III. The residue insoluble in water, proceeding from the alcoholic solution of lac, diluted with water and distilled, is dissolved in a quantity of absolute alcohol, equal to its own bulk, and mixed with eight times its volume of ether. This throws down a viscid preci- Chemischc Untersucluingcn, iv. li!. iMMlli ««ki (li III' ! 11 1 554 RESINS. pitate, which ia resin b of lac, combined with ether. It loses its tarry consistence when the ether is evaporated away. Lac contains -j-'^ths of its weight of this resin. (2.) Resin b, thus obtained, possesses the following properties : — It is hard. It dissolves in cold alcohol of 0*860 or in stronger alcohol. When this solution is mixed with water and distilled, the resin precipitates in the state of a firm jelly. When put into boil- ing water it conglomerates into a resinous mass. When heated it melts and swells, giving out the odour of melted lac. It hiis the property of precipitating acetate of copper. The precipitate is a powder soluble in ether and oils, but insoluble in alcohol. Resin b, while in solution in alcohol, decomposes carbonate of magnesia by the assistance of heat, and dissolves the magnesia. But the resinate of magnesia obtained by double decomposition is insoluble in alcohol. The resinate of potash dissolves readily in water, and is not pre- cipitated from its solution by an excess of potash. By means of it, brown-coloured reslnates of the earths and metallic oxides may be obtained, which are insoluble in alcohol, ether, and the oils. This resin, as well as resin a, has the curious property of dis- solving without alteration in cold potash ley, and of being partly converted into oleic and margaric acid when the liquid is boiled. This, at least, is the opinion entertained by Unverdorben. IV. The ethereal solution from which resin 6 had precipitated, is mixed with water and distilled. A resinous substance remains, which is dried and dissolved in a small quantity of ether. This solution is mixed with its own bulk of naphtha, and the ether is evaporated away. The greatest part of the resin now falls from the naphtha, which retains in solution the fat of the coccus, and a small quantity of resin. The weight of the resin, separated in this manner, does not exceed two per cent, of the weight of lac employed. It consists of two resins, which may be distinguished by the names c and d. To separate them from each other, dissolve them in the smallest possible quantity of potash, and mix the solution with sul- phate of magnesia. When the precipitate that falls, consisting of the two resins combined with magnesia, is digested in caustic potash, the resinate d of magnesia is decomposed, and the resin d dissolved in the potash, while the subresinate of resin c remains under the form of a violet-coloured powder. The resins thus separated are thrown down, each, by muriatic acid, washed and dried. (3.) Resin c, while in a state of fusion, is reddish-yellow by trans- mitted light, and black by reflected light, and has the aspect of a resin. When slowly cooled, or when its alcoholic or ethereal solu- tion is evaporated, it is deposited in acicular crystals of an orange- yellow colour. The crystals become particularly bulky when muriatic acid has been added to the ethereal solution. At the tem- perature of 59 °, it requires about 20 times its weight of ether or alcohol to dissolve it. At a boiling temperature it is much more soluble in LAC. 555 these liquids. Oil of turpentine dissolves it with difficulty cold, but more readily when hot, and when the solution cools the resin is deposited again in crystalline flocks. Concentrated sulphuric acid dissolves it, assuming a red colour, and does not decompose it unless raised to a boiling temperature. Concentrated nitric and muriatic acids dissolve a small quantity of it which is precipitated by water. When assisted by heat, nitric acid decomposes it. It possesses the properties of an acid in a very marked manner. With colourless bases it forms compounds, which are violet coloured when neutral; but brown when they contain an excess of resin. This explains why certain violet combinations become brown when exposed to the air, the carbonic acid of the atmosphere combin- ing with a portion of the base. Hence the violet colour is restored by adding an additional quantity of the base in order to saturate the resin. The resinate of potash dissolves readily in water. We may add a certain quantity of potash to the solution without throwing down the resinate ; but a greater quantity causes it to precipitate. When the resinate of potash is dried, it assumes the appearance of a gum. It dissolves in boiling alcohol, but is deposited in a gelatinous state when the solution cools. Ether does not dissolve it, but it deprives it of the property of forming a red solution with water. After digestion in ether, it dissolves in water with a brown colour.* By double decomposition, resinates of the earths and metallic oxides may be obtained, which sve violet when the bases are colour- less, and reddish-brown when these bases have a colour. They are powders, insoluble in ether and alcohol, decomposable by hydrate of potash, with the exception of resinate of magnesia. This last resinate may be obtained either by double decomposition or by boil- ing a solution of resin c with carbonate of magnesia. It is a powder having a violet colour. Hesin c may be extracted from lac, simply by boiling the alco- holic solution of the lac with carbonate of magnesia. It precipitates, when this is done, in combination with magnesia, from which it may be separated by muriatic acid. (4.) Hesin d is soft and flexible, and seems to contain some of the fat of the coccus. When heated to 212° it melts. It is very soluble in alcohol and ether. Potash and ammonia dissolve it, assum- ing a brown colour. When the ammoniacal solution is evaporated, the alkali is dissipated. Potash throws down the resinate of potash from its concentrated solution ; the precipitate is brown and viscid. The resinate of copper is a powder, which does not dissolve in ether. V. We must now speak of the gelatinous precipitate which falls during the cooling of the boiling alcoholic solution of lac, mentioned * The red colour is doubtless owing to the presence of « little of the red colour- ing matter of lac, wiiich is removed by the ether. UIMMHHMiliii Hi 1 11 M I Sl cM i| K i 556 RESINS. in paragraph I., and stated there to amount to about 8 per cent, of the lac employed. After having been washed with alcohol and dried, it is a hard, brown, porous body, with a resinous aspect. We shall call it resin e, because it has more analogy with the resins than with any other set of bodies. (5.) Resin e may be kneaded in boiling water, but it does not fuse except at a high temperature, and while melting it undergoes decomposition, and is converted into a true resin. While cold, it is insoluble in alcohol, ether, and volatile oils. Potash dissolves it, assuming a brown colour. And, according to Unverdorben, a part of the resin is decomposed ; for acids throw it down of the consis- tence of tar, from which ether extracts oleic and margaric acid, and resin. If we add naphtha to this ethereal solution, the resin preci- pitates, and the oily acids alone remain in solution. JResin e dissolves also in ammonia mixed with a little alcohol, and this solution contains oleate and margarate of ammonia. The resinate of copper is brown, and insoluble in ether. VI. The portion of lac insoluble in boiling alcohol, is the laccin of John, which has been described in a preceding part of this Section. It contains besides, a little wax, resin, and fat, besides foreign matters, such as fragments of wood, envelopes of coccus, &c. The wax may be separated by digestion in naphtha or ether. The laccin may be then dissolved by digestion in alcohol of 0*879, previously mixed with a little muriatic acid. Water is poured into this solution, the alcohol is distilled off, and the laccin remains mixed with a little resin. When dried and boiled, first in alcohol and then in ether, the resin is dissolved and the laccin remains. Laccin extracted in this way was found by Unverdorben pos- sessed of the following properties : — It was brown, brittle, trans- lucent, composed of small particles conglomerated together, and has a greater resemblance to resin than to any thing else. At 212° it is not altered; but it melts at a higher temperature, swelling up and giving out the odour of lac. Its composition is then altered. It swells up a little in alcohol and ether ; but does not dissolve. It is equally insoluble in the fixed oils. Alcohol, acidulated by sulphuric or muriatic acids, dissolves it by long-continued digestion, and water throws it down from this solution. But if we saturate the acid solution with carbonate of lime, the laccin, instead of being {)recipitated, is converted into two resins, soluble in alcohol, which lave some analogy to resins a and b of lac. Concentrated acetic acid, whether alone or mixed with alcohol, does not dissolve laccin. Caustic potash dissolves it by a boiling temperature, and converts it into resins a and b. If we add alcohol to the potash solution, this change takes place without the applica- tion of heat. The great purpose to which lac is applied, is the making of seal- ing-wax. The best red sealing-wax is made by melting together, in a VL»rv gentle heat, AMBER. 557 rittle, trans- akinj? of seal- 48 parts of shell lac 19 pn 's of Venice turpentine t \ of balsam of Peru 32 V:.. ts of cinnabar, in fine powder 100 The fused mass, when cooled to a certain point, is cast in moulds. In the cheaper kinds of wax the lac is replaced by rosin, and the cinnabar by red lead. The finest black sealing wax is made of 60 parts shell lac 10 parts turpentine 30 parts levigated ivory black 100 The colouring matter of yellow wax, is chromate of lead ; that of blue sealing wax, cobalt or mountain blue ; that of green wax, mountain green, or oxide of copper. Lac is employed also to lute together broken stoneware vessels. It enters likewise as a frequent ingredient into varnishes.* SECTION XIX. — OF AMBER. This substance is undoubtedly of vegetable origin ; and though it differs from resins in some of its properties, yet it agrees with them in so many others, that it may, without impropriety, be referred to them. For the chemical investigation of the properties of this substance, we are chiefly indebted to the labours of Hoffmann,! Bourdlin,J Stockar de Neuforn,§ Heyer,|| and it has occupied the attention of Mr Hatchett. More recently its properties have been investigated by Berzelius,^ and by Unverdorben. - The best account of amber varnish which I have seen is by Nils Nystrom, in the Stockholm Transactions for 1797.** Amber is found in beds of wood coal, deposited in Greenland, Prussia, France, Switzerland, &c. At Trahenieres, in the Henegau, it is found in clay mixed with a certain quantity of the debris of wood nearly in the state of wood coal. The greatest part of the amber of commerce is found in Prussia, on the south shore of the Baltic, being thrown up from the sea between Konigsberg and Memel. It is supposed to be derived from beds of wood coal in the * The reader will find a valuable set of experiments upon a spurious kind of lac, by RIM. Nees von Esenbeck, and Clamor Marguart, in the Ann. der Phar- macie, xiii. 286. t Obs. Phys. Chem. pp. 60 and 198. % Sur le Succin. Mem. Par. 174-2, p. 192. $ Specimen. Chem. Med. Iiiaugur. de Succino in Genere et speciatim de Succino Fossili Wisbolzensi, 17G0. This tract contains a very copious set of ex- periments ; which, however, do not always agree with those of other chemists. Wasserberg's Treatise on Amber is chiefly an abridgment of Stockard's. ij Chemische versuche mit Bernstein, 1787. 1 Ann. de Chim. et de Phys. xxxviii. 219. I have seen the paper only through the medium of Crell's Journal. It is inserted in Crell's Annals, 1799, m. 171 and 253. 558 RESINfl. basin of the Baltic. It is cast ashore also in considerable quantities on the east coast of England. There seems no reason to doubt that amber proceeded originally from the trees which accompany it, and that it was a resin held in solution by a volatile oil. That it was at one time liquid, is obvious from the insects which are occasionally found buried in it. No living insect is known exactly similar to those found in amber ; showing that a very long period must have elapsed since the trees vegetated from which it flowed. Amber is a brittle, light, hiird substance, usually nearly trans- parent ; sometimes almost colourless, but commonly yellow or even deep brown. It has considerable lustre. Its specific gravity is 1'0G5. It is tasteless, and without smell, except when pounded or heated, when it emits a fragrant odour. When heated it softens ; but, as far as is known, cannot be melted without losing some of its weight, and altering its appearance. In a strong heat it burns, leaving a small quantity of ashes, the nature of which has not yet been ascertained. Water has no action on it ; but alcohol, by long digestion, dissolves about ^th of the amber, and forms a coloured solution, which when concentrated becomes milky when mixed with water. The precipitate possesses the j-roperties of a resin. The residuum of the amber is not acted on by alcohol. Though amber be roasted before the action of the alcohol, the tincture is still formed. Hence we learn that the resinous part of amber is not expelled by a melting heat.* When amber is treated with a boiling fixed alkali, it is almost completely dissolved, according to Hoff'mann, and the compound possesses the qualities of soap ; for it is soluble in water and alcohol, and not thrown down by water. Mr Hatchett found that the alkalies act only partially on amber, extracting a yellow tincture. Probably this ingenious chemist did not continue the process long enough ; for I have accidentally ascertained, that a weak solution of potash is capable of dissolving amber completely without the assistance of heat, provided it be allowed to act for a sufficient time. I had formed a weak solution of potash (I believe carbonate) as nearly as possible of the specific gravity of amber, and I had put into it some amber powder, to show the supposed currents of Count Rumford during the heating of the liquid. On examining the infusion about a month after, I found the amber all lying at the bottom of the phial. I added more alkali to restore the equilibrium. Some time after the amber was again at the bottom, and it was necessary to add more alkali. Hy this time the solution had acquired a yellow colour. I therefore explained the sinking of the amber, by supposing that the potash had dissolved a portion of it, and that this had altered the specific gravity of the solution. Not knowing at the time that any experiments had been made on the subject, 1 put aside the phial to ascertain the result. Three years after only two or three particles of the amber at most could be detected, the rest having dissolved completely. ♦ Ileyrr. AMBER. 559 The weaker acids have no action on amber. Sulphuric acid converts it into a black resinous mass. Nitric acid acts upon it ; when assisted by heat, nitrous gas is emitted. The amber is first converted into a light resinous substance, ar.d at last dissolves com- pletely. Heyer, who first made this experiment, could obtain neither oxalic nor acetic acid by the action of nitric acid on amber. That nitric acid is really capable of dissolving amber has been verified by the experiments of Ilatchett, who found it soluble M'itli the same phenomena as resins in general. Amber consists of a mixture of difibrent substances ; namely, 1, a volatile oil; 2 and 3, two resins soluble in alcohol and ether; 4, succinic acid ; and 5, a bituminous substance, which resists the action of all solvents, and which constitutes the greater part of the amber. These principles may be separated from each other in the following way : — Reduce the amber to a very fine powder, and digest it in a close vessel with ether, renewing the solvent till it ceases to dissolve any thing more. In this way about 10 per cent, of tlie amber may be dissolved. If we mix this solution, which is pale yellow, with water, and distil off the ether in a retort, we find swimming on the surface of the water in the retort a soft transparent resin, almost colour- less when in very thin layers, and yellow when in quantity. This resin has a smell similar to that of amber while pounding. It adheres to the fingers. It gradually loses its viscidity, but long retains its softness and smell. If we heat it while on the surface of the water after the ether has been distilled off, there passes slowly along with the water a little volatile oil, which dissolves in water. Bv this treatment the balsam is converted into a resin, which has a pale yellow colour, is opaque and brittle, and may be rubbed into powder between the fingers. The water on which the resin swims in the retort is acid, and when left to spontaneous evaporation, deposits crystals of succinic acid. We see from this, that succinic acid exists ready formed in amber, and that it is not formed during the distillation. Indeed, Unverdorbcn has shown, that it may be extracted from amber by means of an alcoholic solution of potash. The water found in the receiver, after the distillation, contains some drops of volatile oil ; but furnishes no more of it when cooled down to 32°. It has o strong and agreeable odour, resembling at once oil of pepper and oil of rosemary. Its taste is at first cooling, then aromatic, and it leaves an impression of heat, which continues long. The resin separated from the volatile oil is very fusible. In boiling water it softens, and unites into one mass. When fused, at an elevated temperature, it remains transparent after cooling. It dissolves readily in the alkalies when in excess. But the compound which it forms is insoluble in uncombined alkali. When the resinate solution is evaporated to dryness, it leaves a transparent varnish, partly soluble in water, while a portion remains, swelling into a mu- r : .-ll J \ 5 ; 99 560 RESINS. cilaginoua mass. This resinate is easily decomposed by means of an acid. These two resins may be also separated from each other by di- gesting them in cold alcohol of 0*84, which dissolves the one, and leaves the greater part of the other. If we heat the alcohol, both the resins are dissolved ; but one of them precipitates partly when the solution cools, and partly when it is left to spontaneous evapo- ration. Finally there remains a limpid yellow solution, which, when evaporated to dryness, leaves a soft limpid resin with a smell like volatile oil of amber. This resin melts at 212°. It is very sol- uble in alcohol and ether. It dissolves also in the alkalies, and the solution, which is yellow, gives, when evaporated, a transparent yellow mass, which is soluble in water and alcohol, but which de- posits a mucilaginous matter, when it still retains an excess of resin. The solution of this resinate of potash is precipitated by potash. Mu- riatic acid throws down the resin in the state of a bulky gelatinous mass, almost white Jifter being dried, and breaking with a vitreous fracture. When melted it gives out water and becomes yellow. The resin which has been deposited in a pulverulent state, is more soluble in absolute alcohol. It enters with difficulty into fusion. When in fusion it is yellow, but on becoming again solid, it is quite transparent. It dissolves in the alkalies, and the solution, which is colourless, and which is precipitated by a new dose of alkali, gives, when evaporated, a white mass, opaque and swelling, and partly dissolving in water. The acids throw down the resin from this compound in the state of a hydrate, which is semitransparent, as long as it continues moist. The portion of amber not soluble in ether may be called the hitii^ men of amber. It is insoluble in alcohol, the fixed and volatile oils, and in caustic alkalies. It has the form of a light yellow powder, possessing the principal properties of amber. When heated in a spoon, it becomes brown, giving out the smell of burning fat, but it does not melt. When heated in a distilling apparatus, it gives out a colourless empyreumatic oil, and melts into a deep brown nmss ; and if the distilling be continued, is almost totally converted into empyreumatic oil, having at first the smell of oil of wax, and ulti- mately that of oil of amber. A very little charcoal remains in the retort. If we stop the process as soon as the bitumen of amber has en- tered into fusion, we obtain a resinous-looking mass, which, when cold, is transparent like rosin, when in small pieces. It is easily reduced to powder, and the powder is strongly electric. Alcohol, when digested on it, separates a small quantity of yellow resin, very fusible, and very little soluble in the alkalies. Ether digested on it, after the alcohol, extracts a considerable portion of matter, leaving a brown and viscid mass. When the ether is evaporated, there re- mains a hard transparent resin of a brownish-yellow colour. The portion insoluble in ether dissolves both in oil of turpentine and in naphtha, with the exception of a yellow, transparent, elastic means Oi iier by di- ; one, and ohol, both irtly when ous evapo- )n, which, ith a smell is very sol- us, and the Dransparent t which de- ess of resin, otash. Mu- gelatinous li a vitreous J yellow, ate, is more into fusiottr d, it is quite on, which is alkali, gives, , and partly in from this insparent, as lied the bitu- volatile oils, ;llow powder, I heated in a ing fat, but it i, it gives out 3rown mass; onverted into tvax, and ulti- cmains in the imber has en- which, when It is easily nc. Alcohol, ow resin, very dicrested on it, natter, leaving ated, there re- colour. 1 of turpentine sparent, elastic AMBER. 5GI substance, which is insoluble in all these liquids. After the evapo- ration of the oil, tliis insoluble matter becomes hard and brown, and has exactly the appearance of the original bitumen of amber. When assisted by heat, oil of turpentine and the fixed oils dissolve easily the melted resin, but always leave untouched the elastic mat- ter just mentioned. Absolute alcohol poured into the solution throws down the greatest part of the resin, and ether also occasions a precipitate, though less abundant. The bitumen of amber has some resemblance to the substanc;:* formed when a current of chlorine passes through an alkaline solu- tion of lac, and which remains when we dissolve the bleached resin of lac in alcohol. That substance, like bitumen of amber, when melted in a retort, gives a brown transparent resin, from which alcohol extracts a small quantity, and ether a larger quantity of matter, and which afterwards gives out to oil of turpentine a red- dish-yellow resinous substance. The residue insoluble in that oil consists of a brown elastic matter, which hardens when dried, and appears to be a portion of the primitive matter unaltered. The principal difference between the properties of the bitumen of amber, and of the substance from lac, is the solul)ility of this last substance in potash, which causes it to assume the characters of a resin. But if we mix the bitumen of amber with a solution of caustic alkali, and evaporate till the amber fuses in the hydrate of potash, there is disengaged a quantity of empyreumatic oil, and we obtain a resinate of potash, which yields to water the excess of alkali which it contains. The alkaline solution is colourless, and when neutralized by muriatic acid, it gives a small quantity of fusible precipitate, which has a strong smell of oil of amber, as long as any traces of succinic acid remains in the liquid. But this precipitate does not seem to consist of the bitumen of amber. It is rather a residue of the two other resins which had not been completely ex- tracted from the coarse powder of amber. The resinate of potash dissolves in pure warm water, with a brown colour, leaving unaltered the bitumen of amber. When the solution is evaporated we obtain a brown matter which does not ad- here to the glass, and which, when redissolved In water, and mixed with muriatic acid, gives a greyish-white mucilaginous precipitate. This precipitate consists of a hydrate of the resin. It parts with its water when fused, and then is a deep-yellow hard and transpa- rent resin, soluble in a small quantity of absolute alcohol. It dis- solves very nearly in ether, and altogether in oil of turpentine. Now that we know the constituents of amber, it will be easier to explain the way in which it acts with other bodies. Water has no action on it, or only extracts a small quantity of succinic acid. Absolute alcohol dissolves the same substances as ether. But that these liquids may act, the amber must be in the state of a very fine powder. The alcoholic solution is light yellow, and when evapo- rated leaves a soft yellow transparent resin. If we pour water into the alcoholic solution v. becomes milky, and continues so after the 2 o ' Ilii . '■ 'f .1 I I! is i I ', I f* 'I! i i 'II I 502 RESINS. distillation of the alcohol ; yet it deposits a small quantity of pale yellow resin. When the milky liquid is evaporated to dryness, we obtain a pulverulent substance, which gives out to water succinic acid, and the residue, insoluble in water, consists for the most part of that pulverulent resin, which is but little soluble in cold alconol. The aqueous solution gives, by evaporation, a pale yellow extractive matter, from which ammonia throws down a yellow substance inso- luble in water. The filtered liquid, when evaporated, yields crys- tals of succinate of ammonia. According to Unverdorbon, amber in powder dissolves in concen- trated sulphuric acid, which acquires a brown colour. When water is poured into this solution, the greatest part of the amber is thrown down. The precipitate contains a certain quantity of combined sulphuric acid, and when distilled, besides the ordinary products of amber, it gives out a little sulphuretted hydrogen gas. The por- tion of amber which the water does not precipitate from the acid solution, remains dissolved when the acid is neutralized. It resem- bles extractive, but is not precipitated by the salts of lead and tin. If we boil a solution of amber in sulphuric acid, we obtain, as usual, artificial tannin and charcoal. Nitric acid converts amber into a resinous-looking substance, and afterwards dissolves it. If, after having reduced amber, to a fine powder, we boil it in a solution of hydrate or carbonate of potash, the alkali dissolves very little resin, but a great quantity of succinic acid. By this process, rightly conducted, all the succinic acid might be extracted from amber without rendering it unfit to serve for making amber varnish after having been fused.* SECTION XX. OF PASTO IlESIN. Boussingault has described the characters of a resinous substance employed by the Indians at Paste, in the northernmost parts of Peru, for covering wood and rendering it impermeable to water.f The plant which yields it is unknown. It is procured from Macao, seven days' journey east from Pasto. It is not liquid, but soft and elastic like gluten of wheat. When first applied to the wood in thin elastic plates, it may be scratched off by the finger, but it soon hardens. It has neither taste nor smell. It is heavier than water. Its fracture is vitreous. It is too tough to be pounded ; it can only be rasped down. It becomes electric when rubbed. When heated a little above 212° it becomes elastic like caoutchouc, and rebounds when thrown against a hard body. But it loses its elasticity on cooling. Alcohol separates a little green resin from it, but does not act upon the residue even at a boiling heat. It is insoluble in ether, but swells up and becomes gelatinous. It swells also in fixed oils, but does not dissolve in them. It is insoluble in volatile oils and in water. Sulphuric acid dissolves • Berzeliiis, Traitc de Chimie, vi. 594. t Ann. dc Dhim. ct de Phys. Ivi. 216. VARNISHES. 5fi3 ' of pale neas, we succinic lost part I alconol. jxtractive mce inso- jlds crys- in concen- hen water • ia thrown combinc'i iroducts of The por- ra the acid It resem- id and tin. ! obtain, as verts amber ves it. 5 boil it in a asolves very this process, tracted from nber varnish lus substance lost parts of to water .t rom Macao, )le vheat. When be scratched her taste nor |)us. It is too It becomes 2° it becomes igainst a hard jf separates a esidue even at , and becomes isolve in them, acid dissolves it, out it is precipitated by water. Potash dissolves it, and con- verts it into a species of soap, which is soluble in water, and from which it is precipitated by acetic acid exactly similar to the state in which it is used by the Indians at Pasto. It has a silky lustre, and may be drawn out into thin membranes like gluten. In this state it contains water and a little acetic acid. Exposed to the air, it dries, becomes brown, and loses its elasticity. At 206^ it melts, and gives out all the water and acetic acid which it contains. After cooling it is brown, very tenacious, and dissolves readily in alcohol, ether, and oil of turpentine. In this state it makes an excellent varnish. Boussingault analyzed it, and found it composed of Carbon 70'66 or 10 atoms = 7*5 or per cent. 71*43 Hydrogen 9-82 or 8 atoms =1 _ — 9-52 Oyxgen 19'52 or 2 atoms = 2 _ — 19-05 100-00 10-5 100-00 It is, therefore, the same in constitution as rosin or copaiva resin, with an additional atom of oxygen. SECTION XXI. — OF VARNISHES. The greater number of the resins which have been described in this Chapter are employed in the preparation of varnishes. For this purpose they are dissolved in alcohol, or oil of turpentine, or in a mixture of oil of turpentine and a drying oil. When these solu- tions are spread upon a surface the solvent evaporates, and leaves the surface covered with a thin coating of the resin employed, which gives a shining appearance to the surface so covered, and at the same time screens it from the action of moisture and of the atmo- sphere. This covering is what is called, in common language, a varnish. Alcohol varnishes are best made with absolute alcohol. They dry rapidly, and resist even the action of common spirits. Usually they are prepared from alcohol of the specific gravity 0-833. When a powdered resin is put into alcohol it softens, and the particles are agglutinated together, which greatly retards the solution. To obviate this inconvenience, the resin is mixed with about half its weight of pounded glass. This prevents the particles from agglo- merating into a mass, or sticking to the bottom of the vessel. It may happen that the varnish, when dry, from the brittleness of the resin employed, may crack, or even fall oft' in powder when the sur- face is struck. This is obviated by adding to the varnish a small quantity of Venice turpentine, which gives the coating of varnish a certain tenacity. But this is only a palliative. For the volatile oil of the turpentine gradually evaporates, and leaves the resin as brittle as ever. The best remedy is to add a little linseed oil, either alone, or mixed with oil of turpentine. Colourless varnish is prepared thus : — Take 6 parts of sandarach 3 parts mastich 1 ; I M I 'i *\l if I f 504 nesiNs. 1 part elctni ^ part Venice turpentine 4 parts pounded glass 32 parts alcohol. solution is effected, filter the varnish through paper This varnish is hard, and destitute of flexi- When the on a covered funnel. bility. But the most colourless varnish known is made from copal, steeped in ether till it swells out, and then dissolved in hot alcohol, added by small portions at a time. When copal, which has been previously melted with a little turpentine, is dissolved in absolute alcohol, a varnish is obtained, having a yellow colour. This varnish is very much used, and the yellow colour is concealed by adding a little blue, or by giving a slight tint of blue to the surface before the varnish is applied. Lac varnish (excepting that it has a brown colour) is the best of all varnishes. To make it, take 8 parts shell lac 4 parts sandarach 1 part Venice turpentine 4 parts poundod glass 60 parts alcohol. This is the varnish applied over brass ornaments, and technically called lacker. The surface of the brass is made quite clean, by steeping it in a weak solution of nitric acid. It is then washed in hot water, dried speedily in bran, and covered instantly with hot varnish. This prevents the action of the air, which tarnishes brass with great rapidity. Oil of turpentine varnishes, like those of spirit of wine, are either colourless or coloured. A colourless varnish is made thus : — 24 parts mastich 3 parts Venice turpentine 1 part camphor 10 parts pounded glass 72 parts oil of turpentine. This is the varnish usually employed to cover oil paintings, maps, and engravings. The paper ought first to be covered with a thin coating of isinglass, which prevents the varnish from passing through the paper and rendering it transparent. Several processes for making copal varnishes have been given in a precedmg Section of this Chapter, when treating of copal. To that Section the reader is referred for information on the sub- ject. Both alcohol and turpentine varnishes may be coloured. Yellow by turmeric, anotta, saffron, gamboge. Red by dragon's blood, cochineal, red sandcrs, safflower, orcanette. Green by acetate of copper, or resinate of copper. All the opaque colours may be ob- tained by levigating the respective colouring matters, and mixing them in that state intimately with the varnish. In this way, cin- VAIINISIIES. fi65 rh paper of flexi- m copal, t alcoiiol, has been (1 absolute lis varnish f adding a ace before the best of . technically te clean, by n washed in tly with hot nishes brass !, are hus : — either ntings, maps, ;d with a thin from passing ve been given ting of copal. 3n on the sub- ,ured. Yelloto ■ragon's blood, II by acetate of urs may be ob- jrs, and mixing this way, cin- nabar, indigo, Prussian blue, chromato of lead, &c., may be mixed with varnishes to communicate their respective colours. The following is the receipt for making a gold coloured var- nish : — 8 parts shell lac 8 parts sandarach 4 parts Venice turpentine 1 part dragon's blood \ part turmeric \ part gamboge 64 parts oil of turpentine. A similar varnish, having alcohol for its vehicle, is formed of the following ingredients : — 4 parts shell lac 4 parts sandarach 4 parts elcmi 1 part dragon's blood 192 parts alcohol of 0-85. The varnish made in this way is red, and requires, before having the golden colour, to be mixed with a yellow colouring matter. For this purpose a similar varnish to the preceding is made, only sub- stituting gamboge for dnigon's blood. These two varnishes are mixed in the proportions found by trial best for giving the varnish a golden colour. Brass may be made to assume a golden colour, by corroding its surface for some minutes by means of a mixture of 6 parts nitric acid free from muriatic acid, and 1 part of sulphuric acid ; then, it is to be washed and put into a saturated solution of bitartrate of potash. Finally, it is dried, by rubbing it in saw-dust. The varnish is now applied with a pencil, and dried by the application of heat. When wood is varnished, the varnish requires to be polished, in order to give the surface the requisite lustre. For this several coats of varnish are applied in succession, taking care that those first applied are dry before a new one be laid on. After being allowed to dry for some days, the surface is rubbed with tripoli and oil, and when the surface is quite smooth, the polish is finished by rubbing the varnish with fine starch till it has acquired the requisite brilliancy. When rosewood tables are varnished, they are first polished with pumice, and then with tripoli and linseed oil. The whole is then rubbed over with lac varnish, mixed with a very little linseed oil. During the rubbing the varnish dries, and acquires polish.* * Bcrzclius, Traito de Chimic, v. 533. I ! Sim (MM KKIllNlt. CHAPTER X. o r a V M u K s 1 N s. TiiBiiK nro many plants wliirli, when cut or pierced, give (> grains of gviiu renins digested in alcohol : — Annnoniac ..,.■» 6S Asafiutida . . . 51 Olibanum ..... 44 Myrrh 40 Gamboge il Nitric acid acts upon them with energy ; converting them first into a brittle mass, and then, with the assistance of heat, dissul' mg I'm Hy evaporating this solution, Mr Ilatchctt obtained, irom aiit.iU) uHC and asafoftida, a portion of artificial tannin; but in- did not Succeed in procuring it by the same means from uUbanuni, myrrh, and gamboge.* Their specific gravity is usually greater than that of the resins. The gum resins, in a medical point of view, may be divided into four sets; namely, 1 The fetid gum resins 2 The stimulating 3 The cathartic 4 The sedative. In this Chapter we shall take a view of the most important i^mn resins belonging to each of these Divisions. 11 I! I! DIVISION I.— OF FETID GUM RESINS. These gum resins have an alliaceous, or at least a peculiar smcU, and have a good deal of resemblance to fatty matter. The princi- pal fetid gum resins are the five following : — 1 Ammoniac 4 Opoponax 2 Galbanum 5 Sagapenum 3 Asafaetida SECTION I. — OF AMMONIAC. The plant which yields this gum resin is a native of the north of Persia. It was brought lately to p]ngland by Colonel Wright, and has been described by Mr David Don, under the name of Dorema ammoniacum.] It had been previously conjectured by Willdenow that it was the produce of the Heracleum gummifera. He made the seeds vegetate, which are occasionally met with in ammoniac, and constituted the plant which spring from them into a new species • Phil. Trans. 1806. f Philosophical MagHzine (New Series), ix. 47. Mr Don considers ammoniac to be a corruption of armeniacum, indicating the country (Armenia) whence the gum came. ': '\\^ i 5G8 GUM RESINS. under that name. Hut as this plant was not observed to yield am- moniac, Willdenow was not able to establish his opinion.* Araraoniac is imported in small pieces agglutinated together, and has a yellowish-white colour. Its smell is somewhat like that of galbanum, but more pleasant. Its taste is a nauseous sweet, mixed with bitter. It does not melt. Water dissolves a portion of it ; the solution is milky, but gradually lets fall a resinous portion. More than one-half is soluble in alcohol. This portion is a resin. Colour white, soft, and ductile. Melts when heated, and burns like a resin. When heated becomes harder, but not brittle. Nearly tasteless. Soluble in ether and in nitric acid. Precipitated from it m the form of an orange substance, partly resin, partly bitter. A portion re- mains, and gives the liquid a yellow colour. Taste of the solution slightly acid and bitter. Not precipitated by carbonate of soda, ammonia, nitrate of silver, nor acetate of lead. The orange sub- stance has a bitter taste. When heated, readily swells and blackens, but does not flame. Burns without leaving any residuum. Lighter than water. When agitated in water, tinges it yellow, but does not all dissolve. The specific gravity of ammoniac is 1*207. Mr Hatchett found it soluble in alkalies. Neither alcohol nor water, when distilled off it, bring over any thing. According to the analysis of Braconnot, ammoniac is composed of the following ingredients : — Resin Gum Glutinous matter Water Loss 70-0 18-4 4-4 6-0 1-2 100-0 The resin he found brittle and yellow. In these respects it differs from the resin which I extracted from ammoniac, which was soft, and continued so after being exposed to the air for two months. This difference is probably owing to the state of the ammoniac ; sometimes it is brittle and yellow, at other times soft and white. It was in this last state that I examined it. Braconnot found the yellow matter into which this resin is converted by nitric acid soluble in hot alcohol and water. It had the property of dyeing silk a fine yellow colour, not altered by chlorine. The gum which he extracted from ammoniac possessed the properties of common gum, as far as he examined them. It is transparent, yellowish, brittle, soluble in water, and precipitated by subacetate of lead, but not by the acetate, nor the nitrate of lead. The mercurial salts render the solution milky. By nitric acid it is converted into saclactic and oxalic acids, and furnishes also a little malic a<;id. The glutinous matter was insoluble in water and alcohol ; it became black when ' Sec Ann. lie Chim. Ixix. 'JG7. GALBANUM. 569 ,o yield am- * I gether, and like that of weet, mixed jrtion of it ; rtion. More sin. Colour like a resin, rly tasteless, t in the form \ portion re- the solution late of soda, ! orange sub- and blackens, um. Lighter , but does not i 1-207. Mr lol nor water, 5 is composed jse respects it iac, wbicli was or two months, the ammoniac ; and white. It mot found the )y nitric acid of dyeing silk gum which he common gum, ilowish, brittle, ad, but not by lalts render the saclactic and The glutinous me black when dried, and yielded a yellow matter and some oxalic acid when treated with nitric acid.* Ammoniac is an antispasmodic, but undoubtedly the least power- ful of all the fetid gum resins. It is occasionally administered as an expectorant ; but in this country at least, its expectorant powers are not much confided in. It is said to act as a purgative when administered in large doses. It is sometimes used as an external application, in cases of white swelling of the knee joint, &c. SECTION II OF GALBANUM. Mr David Don has lately advanced sufficient reasons for thinking that this gum resin is the product of a plant allied to the genus Si/er. He proposes to call it Galbanum officinale. It is a native of Persia. It has been generally considered as the product of the Biibon Galbanum, an umbelliferous plant, which grows in Africa, Arabia, and Syria.f Galbanum comes to this country from the Levant, in small pieces composed of tears, agglutinated together, of a yellowish or white colour. The best is in ductile masses, composed of distinct whitish tears, agglutinated together by a pale-brown or yellowish substance. The separate tears constitute the best part of the mass. When the colour is dark-brown or bLckish, it must be rejected as bad. Its taste is acrid and bitter, and its smell peculiar. Water, vinegar, and wine dissolve part of it, but the solution is milky. Alcohol dissolves about fths. When distilled it yields about half its weight of volatile oil, which has at first a blue colour. Its specific gravity is 1*2 12.$ According to the analysis of M. Meisner, it is composed as fol lows : — Resin 65'8 Gum 22-6 Cerasin . . . . . I '8 Malic acid . . . 0-2 . Volatile oil ... . 3-4 Vegetable debris ... 2*8 Loss ..... 3*4 100-0§ Besides these substances, traces of malates were found. When galbanum is distilled, it yields acetic acid held in solution by water, then an oil, at first green, then blue, and lastly, reddish-brown. The volatile oil contained in galbanum is colourless and limpid. Its specific gravity is 0*92. Its odour resembles at once that of galbanum and of camphor. Its taste is at first hot, then cooling and bitter. It dissolves easily in alcohol, ether, and the fixed oils. * Ann. de Chim. Ixviii. 69. f Woodville's Medical Botany, i. 98. I Brissoii. § Annals of I'hilosopliy, xiv. 383. 570 GUM RESINS. The resin of galbanum is dark brownish-yellow, translucent, brittle, and tasteless. It is insoluble in spirits, but very soluble in absolute alcohol, in ether, and in almond oil. Oil of turpentine dissolves very little of it, even when assisted by heat. Concentrated sulphuric acid dissolves it readily. Hot nitric acid destroys it, the smell of acetic acid is perceptible, oxalic acid is formed, and there remains a yellow, bitter, brittle substance, which does not melt when heated, but undergoes decomposition, giving out a peculiar odour. When this resin is digested with hydrate of potash, a combination is formed, which is insoluble in water.* The medicinal properties of galbanum are considered as of the same kind with those of ammoniac ; but it acts with more energy, though with less than asafoetida. It has been found useful in hysteria; and has been occasionally administered in chlorosis, asthma, and chronic rheumatism. It is usually given in pills to the extent of from 1 grains to half a dram. It is also used as an external application. SECTION III. OF ASAFffiTIDA. This gum resin is obtained from the ferula asa/celida, a perennial plant, which is a native of Persia. When the plant is about four years old, its roots are dug up and cleaned. Their extremity being then cut off, a milky juice exudes, which is collected. Then another portion is cut off, and more juice exudes. This is continued till the roots are exhausted. The juice thus collected soon hardens and constitutes asajktida. It comes to Europe in small grains of dif- ferent colours, whitish, reddish, violet, brown. Pretty hard, but brittle. Its taste is acrid and bitter ; its smell strongly alliaceous and fetid. Alcohol, according to Neumann, dissolves about f ths of this substance ; and water takes up nearly {-th, if applied before the spirit. A considerable portion of earthy matter remains undis- solved. It yields a volatile oil, both when distilled with water and alcohol. This oil possesses the active properties of the asafoetida itsclf.f The specific gravity of the gum resin is 1*327. According to the analysis of Brandes, asafoetida is composed of Volatile oil . . . . 9*6 Resin 48'85 Gum, with traces of potash and" lime combined, sulphuric, phos- phoric, acetic, and malic acids Mucilage .... Extractive, with malate of potash Sulphate of lime, with traces of phosphate Peroxide of iron and alumina . Impurities .... 19-40 6-4 1-4 6-2 0-4 4-6 • Berzelius, Traite dc Chimic, vi. 144. 96-85 t Nctirnunn's Chemistry, p. 312. ratislucent, soluble in turpentine ancentrated roys it, the I, and there )t melt when uliar odour, combination •ed as of the nore energy, nd useful in in chlorosis, sn in pills to 30 used as an a, a perennial lout four years ity being then Then another i continued till ^n hardens and I grains of dif- retty hard, but ngly alliaceous ves about -^ths applied before remains undis- with water and the asafoetida [s composed of 1-40 •4 •4 •2 •4 •6 |)-85 Ihcmistry, p. 312. ASAFOiTIDA. 571 It is to the volatile oil that this gum resin owes its disagreeable smell. This oil is lighter than water, very volatile, colourless and limpid when fresh, but by keeping it acquires a yellow colour. Its taste is bitter and rather acrid. It is said to be soluble in 2000 times its weight of water ; but alcohol and ether dissolve it in all proportions. According to Zeise, it contains sulphur as a consti- tuent. It probably, therefore, belongs to the same division of oils with oil of mustard, the nature and properties of which were described in a former Chapter of this work. When the resin of asafoetida is digested in ether, it is divided into two different resins, one of which, amounting to ^th of the weight of the gum resin, is insoluble in ether, very soluble in alcohol, alkalies, oil of turpentine, and oil of almonds. It has a deep yellow colour, is brittle, tasteless, and easily fused. The other resin, which dissolves readily in ether, has a deep greenish-brown colour, is brittle, and breaks with a conchoidal fracture. It has an aromatic smell, and its taste is feeble, but simi- lar to that of garlic, and it remains long in the mouth. When heated, it melts, and gives out a disagreeable smell. It is very soluble both in absolute and dilute alcohol, and likewise in ether, and oil of turpentine, and oil of almonds. Chlorine renders it white. Sulphuric acid dissolves it, and water throws it down from this solu- tion. When the solution is heated, sulphurous acid is given off. When we now dilute it with water, and neutralize the acid by an alkali, the surface assumes a sky-blue colour. Nitric acid communicates an orange colour, which gradually passes into sulphur-yellow, ren- dering it bitter, and slightly soluble in water ; but insoluble in ether, and in the fixed and volatile oils. By the continued action of nitric acid, oxalic acid is formed ; and, according to Brandes, mucic acid also. This resin combines with muriatic acid, losing at the same time its greenish colour, and the property of dissolving in weak alcohol. It becomes acid, and now only dissolves in absolute alcohol at a boiling temperature. It dissolves by boiling in concentrated acetic acid, and is again deposited when the solution cools. This gum resin is a good deal employed in medicine as an anti- spasmodic, especially in cases of hysteria. It is also administered as an expectorant in asthma and hooping-cough ; and it has been long a favourite remedy in chlorosis. The dose is from 5 grains to 20, and it is most commonly given under the form of pills ; though sometimes diffused in water. SECTION IV OF OPOPONAX. This substance is obtained from the pastinaca opoponax, a plant which is a native of the countries round the Levant. The gum resin, like most others, is obtained by wounding the roots of the plant. The milky juice, when dried in tlie sun, constitutes the opoponax. It is in lumps of a reddish-yellow colour, and white :!M m ■ 572 GUM RESINS. within. Smell peculiar. Taste bitter and acrid. With water it forms a milky solution, and about one-half of it dissolves. Alcohol acts but feebly. When distilled with water or alcoliol, these liquids acquire the flavour of opoponax, but no oil separates.* Its specific gravity is 1 -622.1 When distilled it yields a brown oil, acetic acid, in which a bitu- minous oil swims, the residual charcoal weighs j^^q of the opoponax distilled. When incinerated it left j^Yo ^^ ^^^ weight of ashes, com- posed of Carbonate of lime Silica Carbonate 1 Sulphate > of potash Muriate j 18 2 15 S5 According to the analysis of Pelletier, to whom we are indebted for the preceding distillation, opoponax is composed of the follow- ing constituents : — Gum 33-4 Wood 9-8 Starch 4-2 Malic acid 2-8 Extractive 1-6 Caoutchouc Trace Wax 0-3 Volatile oil and loss . 5-9 100-Ot Opoponax was formerly employed in medicine, and considered as possessed of virtues similar to those of asafoctida. But at present it is very rarely used in Great -Britain. SECTION v. OF SAGAPENUM. This gum resin is brought to this country from Smyrna, Aleppo, and Alexandria, and is supposed to be the produce of the ferula persica, a plant which Dr Hope described as the plant which yields asafcetida. If it be the sagapenum {myw^rim) of Dioscorides, it was brought in his time from Media. It is commonly in tears agglutinated together. Colour yellow. Taste hot and bitter. Smell alliaceous. Softens between the fingers, but does not melt when heated. Sparingly soluble in water, but almost completely soluble in alcohol. When distilled with water it yields a little volatile oil. The water is strongly impregnated with the flavour of the sagapenum. § When distilled with water it gives a volatile oil. It was analyzed by Brandes, who found it com- posed of Neumann's Chcni. p. 31G. I Anil, dc Cliim, Ixix. 90. f Brisson. J Neumann's Clieni. p. 310. ith water it Ucohol acts ese liquids Its specific bich a bitu- le opoponax ashes, coin- are indebted f the foUow- D 4 8 2 8 6 [ace ^3 considered as Jut at present tiyrna, Aleppo, ! of the ferula nt which yields )ioscorides, it Colour yellow. IS between the oluble in water, illed with water ;ly impregnated i with water it 10 found it com- ison. leni. I). 31G. SAGAPENUM. 573 Volatile oil . . 3-73 Resin .... 50-29 Gum, with potash and some salts 32*72 Mucilage .... 4*48 Malate and sulphate of lime . 0*85 Phosphate of lime . . . 0*27 Foreign matters . . . 4*30 Moisture .... 4'GO 101-24 The volatile oil is pale yellow, very fluid, and lighter than water, has a very disagreeable alliaceous smell, and a bitter acrid taste somewhat like that of onions. It appears to contain a more volatile oil with an odour of onions, and having a taste at once analogous to that of turpentine and camphor. When the volatile oil of Saga- penum is exposed to the air, it is speedily changed into a transpar- ent resin. It dissolves readily in alcohol and ether. The resin of sagapenum is decomposed by ether into two resins. The one, insoluble in ether, is yellowish-brown, brittle, insipid, and destitute of odour. When heated, it swells up and fuses. It is very soluble in alcohol. Oil of turpentine and oil of almonds do not dissolve it, even when assisted by heat. It dissolves readily in caustic potash, but not in ammonia. It constitutes abouc 2-38 per cent, of the sagapenum. The other resin dissolves in alcohol and ether. It has a reddish- yellow colour, is transparent and soft ; but when long kept it be- comes hard. It has the same odour as sagapenum, and a bitter and disagreeable taste. When heated it melts, swells, and catches fire. It is but little soluble in oil of turpentine and oil of almonds. When put into hot chlorine water, it assumes a green and a blue colour. Sulphuric acid dissolves it, assuming a deep red colour. When we pour water into the solution, a deep violet substance -vims on the surface, and the liquid becomes red. Boiling nitric acid partly dis- solves it, oxalic acid being formed, while a yellow brittle bitter- tasted resinous matter remains behind. This resin is slightly soluble in water, very soluble in alcohol, oils of turpentine and almonds ; but insoluble in ether. When heated it melts and swells up. When ammonia is poured into the nitric acid solution, a yellow-coloured flocky precipitate falls, solu- ble with a red colour, in an excess of ammonia. When muriatic acid is digested with the resin h of sagapenum, it becomes first pale red, then violet, then blue, and by boiling, red- dish-brown. Alkalies precipitate nothing from this solution. Sagapenum is conceived to possess similar medicinal qualities with ammoniac and asafoetida. But it is not so powerful as the last of these, and is therefore very little used, at least in this country. 1 i ■ i I 'Ml! '7= 1(2 •Hi!: 'jlfi : ; • (IITM niCSINS. DIVISION Il.—Or STIMlJI,ATINO (JUM UKSINH. T\w tonn stimulating, wliii-li I liiiv(« iipplicd tt) this class of frmn rosins, is not very propiM", us tlio fetid mikI tin; ciithartic f^mii resins uiuloiiWtedly possess stiiiiMlMliiif; properties to a jjreater extent tliaii olilunmm, mifrrh, ciiphorbium, niid txHlinm, \\w four <^iiin r«!sins wliieh 1 propose now to deseriln* ; but I eainiot tlunk of any other term whieli would eluuwterize them Ix'tttn". SIUTION I. ()|. (U-IHANHM. This snhstanee is the fankineens(> of the ancients. Thoy ob- tained it, as Dioscorides informs us, from Arabia and India. From Pliny we learn that the tree whidi yielded it was neitln'r known to the (Jreeks nor Homans. At present olibamnn is imported to IahuUju in chests, containin<>; each about a hundred wei<>'ht. It couu«s from diiiorent places, anionur others from the Mast Indies, but the Indiati olibannm is least esteemecl. The tree which yields this gum resin continues still doubtful. The probability is, that dili'erent species of trees furnish it in ditl'erent countries. I iamark is of opinion that the tree which yields tin; Arabian olibannm is the amyris (jilfiid- cmis. It is called by the natives souhiou. Accordin*2 I OSS O'H lUO-Of The oil had a lemon colour, and a smell similar to the oil of lemons. The resin is reddish-yellow, brittle, tasteless, and very similar in appearance to rosin. IJoiling water softens it ; but a higher tem- perature is necessary to melt it. When burnt, it emits rather an agreeable odour. When heated to dryness with potash ley, it leaves a matter which is caj)able of forming a kind of emulsion with boil- ing water. The gum possesses few peculiarities. The infusion of nut-galls • Asiatic Researdie«, ix. ;i77. f Ann. do Ciiim. Ixviii. GO. iss of fjuni iriMIl ITsiUH I'JxUMit tliiin iriim rcsiiH f juiy other MYUIiri. /ivr* They ol>- lulia. Ki'«»"» rr known to un|tortoil to woi«;'lit. It 4 Indies, Itnt ;h yieUls this that (UtVei-tint i is of opinii)" imjiris (jilrnd- o Koorskal, it it the InUian ui-oh, a larf?e o\v suhstanee, l)stanee, pro- taste is aeri() liui r)-2 0-8 loo-ot coil of lemons, verv siniiUiv in a higher teui- uiits rather an 1 ley, it leaves Isioii with boil- jon of nut-galls Ixviii. GO. occasionn a |)rccii)itato in its a(iuoous sohttion. Nitric acid converts it ]iart!y into saclactic acid.* Olilianuui poHsesses stinudatin<^ <|iialiti(>H, and was formerly nuich nHcd as a vuhierary, and in ;;;loetH, and alletttions of tin; chest. Hut at pruHont it in hardly ever used for any otlun* purpose than as a perfume. NK(;TION II. — OK MYltllll. Mr Hrnco (Midi^avoured to prove that the plant which yields this fi^uin resin is a Hi)e»tie.s of Mimosa ;f hut this evist myrrh is transparent, and has a nuldish-brown colour. It is brittb;, and ex- hibits tortuous veins of a lij) of Dioscorides. The month of March is the time for cutting the aloes in the island of Barbadoes. The leaves are cut oft' close to the stem and d( .losited in tubs, so that the juice may run out. When a sufficient quantity is collected, it is heated in copper boilers, and as it becomes more inspissated, it is ladled from one boiler to another and fresh juice added. When of the consistence of honey, it is poured into calabashes, where it hardens by age. Barbadoes aloes is consi- dered as inferior to Socotrine aloes, though it is suspected that they are often substituted for the more valuable variety. Aloes has a reddish-brown colour. It is solid, but softens in the hand and becomes adhesive. Its taste is intensely bitter. Barba- does aloes has a stronger and more unpleasant sniell than Socotrine * Ann. dc Chim. Ixxx. 39, :i 1 , ! «' 580 nUM RRniNS. aloes. It dissolves for the most part in water and alcohol. Water leaves undissolved a brown suhstance, which is partially Hohihle in boiling water, but is ajfaiji dcpositcnl when the lupiid cools. 'I'his substance aut it appears from the experiments of Hraconnot, that it is nothinij else than what used to be called orytlizcde.strnctivc, and to which Herzelius has given the name of aputhcnic,* 'nixed with a little uiuUtered aloes. Tiiis last substance may be separated bv diifcstinj; the whole with oxide of lead mixed with water. Tlio oxide combines with the apotheme, which renuiins behind, while the other matter is dissolved in the water. \iy dijiestiny in very dilute nitric acid, the oxide of lead is dissolved, and the apotheme remains under the form of a brown powder. It is insoluble in cold water, gives a yellowish-brown colour to boiling water, dissolves with ditficidty in alcohol, and is precijjitated from that solution by the addition of water. And when the alcohol is evaporated, the apotheme renuiins unaltered. It is soluble in the alkalies, and precipitated from tiiis solution by the acids, aud the f)recipitate which falls contains an acid in cond)ination. It burns ike tinder, without flame, and witluuit melting. The portion of aloes which diss(dves in water, has received the name of bitter principle of aloes. When the solution is left to itself for some months, it becomes dannny, aiul uuiy be drawn into threads, but it neither putrelies nor deposits nnicus. In that state, it is copiously precipitated by infusion of nutgalls. The bitter principle of aloes, is soluble in weak alcolud, but not in absolute alcohol, nor in ether. Chlorine passes through its solution, causes a coagulum to fall analogous to the jjortion of aloes not soluble in water. Cold sulphuric acid dissolves it without alteration. Cold nitric acid dis- solves it, assuming at the same time a green colour. When heat is appUed to this solution, oxalhydric and oxalic acids are formed, and a reddish resinous substance, having the smell of Vanilla, and detonating when gently heated. The bitter principle of aloes, dissolved in water, becomes lighter coloured when an acid is added, .vhile a slight precipitate falls. The alkalies, and the salts of peroxide of iron, give the solution a deep-red colour. Protochloride of tin throws down a slight preci- pitate. The acetate of lead, tartar emetic, salts of manganese, of zinc and of copper, produce no sensible effect. Nitrates of mercury and silver, occasion a ])recipitate which does not appear till some time after the mixture has been nuide. Aloes is very nmch used in medicine. It is an active and brisk purgative, when given in sr ;h a way that it may enter into solution in the stomach. But it is usually administered in pills, which make their way into the larger intestines, before they are broken up. This is probably the reason why aloes is commonly supposed to have a peculiar action on the rectum. • Traite de Chimie, v. 548. Water \uhlo in . This iiul vi«ry WilH coll aooiinot* rtrncfire, * mixed icuarated ,,: The while tlie i»ry dilute remains colour to •ecipitatcd lie alcohol able in the l3, and the It burns iceived the left to itself ito threads, state, it is r>r principle cohol, nor coagulum ter. Cold ic acid dis- When heat are formed, Vanilla, and omes lighter pitate falls. le solution a slight vreci- nese, of zinc mercury and ill some time SCAMMONT. 8KCTION II. — OF 8CAMMONY. 581 This gum rosin is obtained from the convolvulus scamtnnnia, a dimbing plant which grows in Syria, and was first correctly describ- ed by Dr lliisscl.* Scaunnony i-; obtained from the root of the plant, which alone contains it, ami is iHtllccted in tin* be.| Voyel and Bouillon La (Jranire have analvzed the two varieties of scaunnony that come from Aleppo and from Smyrna. The scamuiony of Aleppo was composed of Resin ..... 60 Gum ...... 3 Extractive 2 Vegetable debris, earth, &c . 35 The scammony of Smyrna was composed of Resin . . . . . Gum ...... Extractive . . . . . Vegetable debris, &c. 100 29 8 5 58 100§ The resin of scammony is yellow, translucent, brittle, and very soluble in alcohol. That from Smyrna scammony is brown, trans- parent, difficult to pound, and its alcoholic solution is deeper than that of the resin from Aleppo scammony. From some trials stated in the Journal de Pharmacie (xiii. 589), it appears that the resin of * See ail ahi idgenicnt of liis account liy Dr Lewis, Neumann's Cheni. p. 303. t llussel's Aleppo, ii. 246. :}: Brisson. § Ann. tie Chim. hxii. 61. f \ ! n I'i ' i 582 GUM RESINS. scammony may be rendered colourless by animal charcoa?, without diminishing its pur3 rKpiidpart and Hiihjuct itanow to tlio aniinoiiiii ciirrotit. To roducn tho ben/mnido formed to a state of purity, the wliito iiiiUtor obtiiincd is wushcd in cold water, and then dissolved in hot water and allowed to orystallize on eoolinir. If the ammoniai^al ffua was not tinite dry, bonzoati? of ammonia is formed during the process, at the cxnensc of the luMizaniidc. When the hoihiig-hot solntion of benzaniido is cooled rapidly, larjjfe brilliant crs.tals are deposited similar to those of ehlorate of potash. Hut if the solntion be cooled slowly, the whole liquid assumes tin* form of a white mass composed of silky needles similar to the crystals of catiein. After one or two days, or sometimes earlier, lar;,^e cavities are formed in the mass in which some well- shaped crystals appear, liy degrees the whole silky crystals undergo this transformation. 'r''e crystals of benzamide are right rhombic prisms, having their acute edges replaced by tangent ])lanes. Two of the faces being much hu'gcr than the others, the crystals usually appear under the form of fonr-sided tables with bevelled edges. These crystals have a pearly lustre, they are transparent, and swim on water as if they were oil v. At 239° benzamide melts into a limpid li(piid, which on cooling congeals into a foliated crystalline mass. When strongly heated it boils, and may be distilled over unaltered. Its vapour has a slight smell of almond oil. It easily catches lire, and bnrns with a fuligi- nous tiaine. It is so little soluble in cold water that it scarcely communicates any Havour to that liipiid. Ihit it dissolves very readily in alcohol. Ether dissolves it also at a boiling temperature, and we can obtain it from that solution in r(>mildr crystals. If benzamide, at tlu ordinary temperature of the atmosphere, bo sprinkled over with caustic potash, not the smallest trace of am- monia can be detected. When the solution is mixed with a solution of iron at the ordinary temperature, no precipitate falls. Nor indeed does aiiv metallic salt whatever occasion any precipitate in it. But if we \)oil the solution of benzamide with caustic potash, abundance of ammonia is disengaged and benzoate of potash formed. When a solntion containing peroxide of iron is raised to the boiling temperature, a subbenzoate of iron is precipitated. If we dissolve benzamide in a strong acid, and raise the solution to the boiling temperature, the benzamide disappears, and benzoic acid se])aratos from the solution, while at the same time a salt of ammonia is formed. When we employ concentrated sulphuric acid the benzoic acid fi rmed sublimes. When nenzamide is boiled with water, that decomposition into benzoic a(;id and ammonia does not take place. Benzamide was analyzed by MM. Wbhler and Liebig, by means of oxide of copper. They obtained li>' ■J iif ,r ■v •:', H lit 41 .! II ■if Ml 1 ^ 111 596 AMIDES, OR AMIDETS. Carbon 68*93 or 14 atoms = 10"5 or per cent. 69*43 Hydrogen 5*78 or 7 atoms = 0*875 — — 5*78 Azote 11 -48 or 1 atom = 1*75 — — 11*57 Oxygen 13*81 or 2 atoms = 2*00 — — 13*22 100 Now chloride of benzoyl is Add 2 atoms of ammonia 15*125 C14 H^ O^ + Chi 100*00 Az2 H« We have C* W O^ + Chi + Az^ H" Subtracting 1 atom sal ammoniac H Chi + Az H' We get Cu 116 02 + Az W which is the composition of benzamide. Thus the way in which chloride of benzoyle and ammonia are capable of forming benzamide and sal ammoniac is evident. The addition of an atom of water changes the benzamide into benzoate of ammonia. When benzamide is heated with an excess of caustic barytes, it enters into a kind of fusion ; the barytes is changed into a hydrate, ammonia is disengaged, while at the same time a colourless oily- looking liquid distils over. It has an aromatic and agreeable smell, and a peculiar sweet taste. It is neither altered by the concentrated acids nor alkalies. Potassium may be melted in it without under- going any alteration, demonstrating the absence of oxygen. The same substance is developed in considerable quantity, and without being accompanied by ammonia, when benzamide is fused with potassium, during which the potassium is converted into a cyanodide. When benzamide is made to pass through a red hot tube, the greatest part of it continues unaltered ; but mixed with a little of the oily substance just mentioned. No deposition of charcoal takes place. SECTION V. — OF BENZIMIDE, OR BIBENZAMIDE. This name (too near the preceding) has been given by M. Laurent to a substance extracted by him from a resinous body, obtained by M. Ed, Laugier, while distilling the oil of bitter almonds,* and which he found afterwards to be a constant product.! The resinous substance was found to contain, at least, three ingredients, an oil, benzoin and benzimide. When treated with hot alcohol, the oil and benzoin remain in solution ; but the benzi- mide is deposited as the liquid cools. It may be purified by repeat- ed crystallizations. It is a white solid, in very light flocks, with a pearly lustre, and destitute of smell. It is insoluble in water, but very soluble in alcohol and ether, and still more soluble in pyroxylic spirit. It • Ann. de Chiin. et do Pliys. lix. 397. t Ibid. Ix. 218. ASPARAMIDE. -'■.97 69-43 5-78 11-57 13-22 00-00 Az^ H" Az H» "aTw ntimonia are dent. The ito benzoate c barytes, it a hydrate, lourless oily- ecable smell, concentrated thcut under- ygen. The and without fused with a cyanodide. lot tube, the ith a little of harcoal takes IDE. \f M. Laurent , obtained by Imonds,* and t least, three treated with )ut the benzi- ied by repeat- rly lustre, and >ry soluble in lie spirit. It Ix. 218. melts and is volatilized without decomposition. It becomes again solid when cooled down to 332°i. It burns with a red flame, giving out smoke, leaving a brownish-black residue. Nitric acid dissolves it when assisted by heat without disengagement of red vapours, and it is not precipitated by ammonia. Boiling muriatic acid dissolves it. Nordhausen sulphuric acid dissolves it, assuming a deep indigo colour, provided the benzimide be perfectly dry. If moisture be present, the colour is at first emerald green, then yellow. Potash ley does not attack it, but if a little alcohol be added, ammonia is disengaged and benzoate of potash formed. Benzimide was analyzed by Laurent, who obtained Carbon 76-53 or 28 atoms = 21 or per cent. 74-66 Hydrogen 4-95 or 11 atoms = 1-375 — — 4-88 Azote 7-00 or 1 atom = 1'750 — — 6-23 Oxygen 11-52 or 4 atoms = 4-000 — — 14-23 28-125 100 C28 Hio 0« W Az C28 Hio 0« + H3 O^ + H^ Az 100-00 Now 2 atoms benzoic acid are 1 atom ammonia Bibenzoate of ammonia is Subtract 2 atoms water There will remain C^s H" O* Az which is an atom of benzimide. We see froin this, that benzimide is bibenzoate of ammonia deprived of two atoms of water. It is there- fore analogous to benzamide, and might perhaps be distinguished by the name hibenzamide. The term benzimide is too near benzamide to be adopted by chemists in general. SECTION VI. — OF ASPARAMIDE. This substance, under the name of asparagin, was discovered in the juice of the Asparagus officinaHs, by Vauquelin and Robiquet in the year 1806.* In 1827, M. Bacon discovered a principle in the root of the althcea officinalis^ or marsh mallow, to which he gave the name of althein.'f Henry and Plisson repeated the experiments of Bacon, and showed that his althein wssthe same with the asparagin of Vauquelin and Robiquet. M. Robiquet in 1809 had discovered a substance in the root of the glycyrrhiza glabra,X or common liquorice, to which Caventou afterwards gave the name of agedoite. Tills substance was further examined by M. Plisson, and shown by him to be identical with asparagin.§ In the year 1830, M. Witts- tock repeated the experiments of the French chemists, || and rendered it probable that the asparajiin obtained iv^m the root of the althcea officinalis was formed during the process of extraction, .and did not pre-exist ready formed in that root. * Ann. de Cliiin. Ivii. 88. f Ann. de Chim. et de Phys. xxxiv. 201. X Anil, de Cliirn. Ixxii. 143. $ Jour, de Pharmacie, xiv. 177. II I'ogjj'eudoifs Annaien der Physic, xx. 346. ' i-i % ■ 098 AMIDES, OR AMIDET8. The best mode of obtaining asparagin from the root of marsh mallow is, according to Wittstock, the following : — The aqueous ex- tract of the root is digested in boiling alcohol, of the specific gravity 0*835, till every thing soluble is taken up. When this solution is set aside for 24 hours, it deposits a pasty matter. Decant off the clear liquor and leave it in a cool place. In 24 hours a crop of small crystals is deposited. These consist of aspamgin, and consti- tute about jd of a per cent, of the marsh mallow root employed. If we distil off the alcohol from the liquid portion, and mix the residue with that portion of the aqueous extract which was at first left undissolved by the alcohol, and dissolve the whole in water, we may extract from this solution an additional quantity of asparagin. The method of proceeding is as follows : — Precipitate the liquid, by acetate of lead, and throw down the excess of lead by a current of sulphuretted hydrogen gas. Filter the liquid and evaporate to the consistence of a syrup. In 24 hours this syrup assumes the form of a mass of crystals. Dissolve in boiling alcohol, and let the crystals of asparagin, which are de- posited from that solution, be dissolved in hot water, and leave this solution to spontaneous evaporation in a temperature between 77° and 95°. The asparagin will crystallize in six-sided prisms, quite white if the aqueous solution has been digested with some ivory black. Asparagin crystallizes in rectangular octahedrons and six-sided prisms. It has no smell and but little taste. Its specific gravity at 55° is 1'5I9. When heated it gives out ammoniacal water, showing that it contains azote as a constituent. At 57° it dissolves in 58 times its weight of water, but it is much more soluble in hot water. Alcohol of 0"&37 is a much better solvent of it than water ; but it is insoluble in absolute alcohol and likewise in ether. According to Henry and Plisson it may be dissolved in weak potash ley and thrown down from that solution by an acid. When digested with strong potash ley, ammonia is given out, and the asparagin converted into aspartic acid. When acids are mixed with it, they combine with ammonia, and aspartic acid is disengaged. This rather confirms the opinion of Wittstock, that asparagin is nothing else than a combination of aspartic acid and water. But if it were so, it is difficult to understand why acetate of lead forms no preci- pitate, when dropt into a solution of asparagin ; though it forms a precipitate when added to an aspartate. Asparagin is not preci- pitated by the other metalline salts, nor by the infusion of nut- galls. Anhydrous aspartic acid has been shown to be a compound of C* H^ Az O*'. Of course aspartate of ammonia is composed of C^ H^ Az O*' -H Az H'' ; and asparagin, or asparamido, is C** IP Az O^ -f. Az H^ SECTION VII.- -OF URETHAN, OK ETHER CARBAMIDE. When chlorocarbonic other is placed in contact with concentrated caustic ammonia, dissolved in water, a violent action takes place, URETHAN, OR ETHER CARBAMIDE. 599 ot of marsh aqueous ex- cific gravity solution is icant off the 3 a crop of , and consti- t employed, ind mix the was at first in water, we »f asparagin. 3W down the gas. Filter In 24 hours Dissolve in hich are de- md leave this I between 11° prisms, quite le ivory black. and six-sided gravity at 55° , showing that es in 58 times in hot water. water ; but it olved in weak I acid. When out, and the are mixed with engaged. This ,gin is nothing ISut if it were orms no preci- ugh it forms a a is not preci- ifusion of nut- a compound of lomposed of C^ c, is C« \V Az UAMIDE. th concentrated ion takes place. the mixture boils, and a kinu of explosion sometimes follows. If the ammonia is in excess all the ether disappears ; sal ammoniac is formed, and a new substance, which Dumas, the discoverer, has dis- tinguished by the name of urethan.* To procure it we must evaporate, in vacuo, the product of the reaction to perfect dryness. The dry matter is then put into a re- Lo-t, and distilled by the ,heat of an oil-bath. A colourless liquid passes over, which, on cooling, concretes into plates, having a pearly lustre. If the solution of this substance renders nitrate of silver muddy, we must distil it again, taking care not to raise the heat too high. Urethan thus obtained is a white solid, fusible below 212°, and capable of being distilled over unaltered at about 226° when dry. But if it be moist, it cannot be distilled over without partial decom- position, much ammoniacal gas being disengaged. It is very soluble in water, both cold and hot. It does not precipitate salts of silver. Nor does its solution react either as an acid or an alkali. It dis- solves very well in alcohol, even when anhydrous. It has so great a tendency to crystallize, that when a few drops of its solution are left to spontaneous evaporation, it always shoots into thin and very transparent crystals. These crystals are anhydrous. Urethan was analyzed by Dumas, by means of oxide of copper. He obtained K. 1'i.n 40*5 or 3 atoms = 2*25 or per cent. 40*45 7-9 or U atoms = 0-4375 — — 7*86 ^en Oxygen 15-6 or ^ atom = 0-875 36-0 or 2 atoms = 2-000 _ _ 15-73 _ _ 35-96 100-0 5-5625 100 Or, doubling the numbers, These atoms may be resolved into 2 atoms carbonic acid 1 atom ether 1 atom ammonia Minus an atom of water C« H^ Az O* C^ O^ C* H5 O H^ Az C« H« Az 0» H O C« H^ Az O* It may, therefore, be considered as a compound of an integrant particle of carbonic ether, and an integrant particle of carbamide. It is analogous in its composition to oxamethan. Urethan may be represented also by 1 atom carbonic ether C O^ + C* H» O or C» H« 0» 1 atom uric acid . . . . C H'' Az O Cfi W Az O^ 5 iJl,: * Ann. de Chim. cc de Phys. liv. 232. H 600 AMIDES, OR AMIDETS. HU !■ I It waa in consequence of this isomerism that Dumas gave this new siibstance the name of urethan. Dumas found the specific gravity of the vapour of urethan to be 3*14. Now, the specific gravity of 6 volumes carbon vapour . =2*5 7 volumes hydrogen gas . = 0*4861 1 volume azotic gas . . = 0*9722 2 volumes oxygen gas . = 2*2222 2)6*1805 3*09 It is, therefore, composed of 16 volumes condensed into 2 vol".mo8. SECTION VIII. OF SULPHAMIDE. This curious compound was discovered by M. Henry Rose, and described by him in the yec i836.* It is well known that all the salts composed of ammonia, and the oxygen acids, contain water, as an essential constituent, since they cannot be deprived of it without decoi (position. Thus sulphate of ammonia, dried on the sand-bath, is SO' + H' Az + HO. Now, since the HO is essential to the salt, the view of the composition given by Berzelius is at least plausible ; namely, that it is a compound of an atom of sulphuric acid, with an atom of oxide of ammonium, or SO' + (Az H* + O). If we combine dry ammoniacal gas with anhydrous sulphuric acid, we obtain a compound possessing very different properties from those of common sulphate of ammonia. The best mode of pro- ceeding is to introduce the vapour of the anhydrous acid into a large glass rece'ver, surrounded by a freezing mixture, and continue the process till a very thin coating of the acid is deposited equably upon the inside of the vessel. The dry ammoniacal gas u now passed into the vessc^ as long as the acid continues to imbibe it. If the coating of sulphuric acid be too thick, ?;he ammonia forms a crust which covers it, and prevents the rest of the acid from being satu- rated. The compound thus formed, when neutral, is a white light pow- der, not altered by exposure to the atmosphere, and dissolves readily in cold water, but is insoluble in alcohol. When we mix it with solution of potash or of lime, the evolution of ammonia becomes immediately evident. But if we bruise it with dry carbonate of barytes or lime, no smell of ammonia is perceptible, till we moisten the mixture with water. When mixed with concentrated sulphuric acid, it gives out no smell of sulplmrous acid. When heated with an excess of concentrated sulphuric acid, it dissolves with difficulty, and separates again when t!ie liquid cools. When heated it melts into a clear licjuid, which concretes, on cooling, into a bisulpliate of ammonia, if the heat has been continued * Anil, fie riiim. et dc Pliy?, Ixii. ii8!). 1:1 SULPIIAMIDE. 001 too long. The retort contains sulphurous acid in the gaseous state, and in its neck there is sublimed a mixture of sulphate and sulphite of ammonia. In the receiver we find gaseous ammonia and sulphite of ammonia, but no trace of sulphuric acid. This conipouud was analyzed by M. Rose, who showed .that it consisted of 1 atom sulphuric acid . . 5 I atom ammonia . . . 2* 125 7-125 But these constituents, consisting of SO' + IP Az, were cer- tainly not in their usual state. For the most concentrated solution of the compound was not precipitated by chloride of calcium or jhloride of strontium, though these chlorides occasioned a copious precipitate, wlien mixed with a solution of common sulphate of am- monia. Chloride of barium throws down a precipitate of sulphate of barytes ; but the whole sulphuric acid could not be thrown down hy this reagent, even aftei* a cou])le of months' digestion ; and never till sufficient heat had been applied to volatilize the ammoniacal salt formed, which recjuires a heat of ignition. These facts show clearly, that though the constituents of sul- phuric acid and ammonia are present in this co ".pound, they are not in their ordinary state, but combined in some other way. The conjecture of M. Rose, that they constitute an amide, together with an atom of water, is as probable as any which, in the present state of our knowledge, we can form. We may represent the compound thus : — S O^ + H^ Az + H O, or an atom of sulphurous acid, an atom of amide, and an atom of water, and distinguish it by the name of sulp/iamide. Ill CHAPTER II. OF BENZOYL AND ITS COMPOUNDS. The researches of VVohler and Liebig, upon the volatile ml of bit- ter almonds, published in 1832,* have thrown «, new and unexpected light on the nature and compounds of the bases of compound vege- table acids. It will be proper, on that account, to lay a somewhat detailed account of them before the reader. The volatile oil, or essence of hitter almonds (as it is called), was observed by Staiigc to liave the property of absorbing oxygen from the atmosphere, and of being converted into benzoic acid. From the researches of INIM. Robiquet and Routron-Charlard, it would a[)pear, that this volatile oil does 'lot exist ready formed in bitter almonds, but only its constituents, and that it is formed by the ac- ? I • Aim. rle Chun, ct de Pliy.s. li. 273. il ..' \/ . 602 BENZOYL AND ITS COMPOUNDS. "1 i ■ {■ if' tion of water on these constituents.* It has been long known that the volatile oil of bitter almonds contains a great deal of prussic acid. MM. Wohler and Liebig obtained the oil which they em- ployed in their researches from M. Pelouze. It had a yellow colour, and the peculiar smell by which it is characterized. They freed it from prussic acid, and the other impurities which it contained, in the following manner : — It was carefully mixed with hydiate of j)otash, and a solution of protochlo"*''e of iron, and after being well agitated, the mixture was subj? d to distillation. All the oil passed over with the water, quite free .roT- prussic acid. It was separated from the water by means of a iiucker, and rectified over quick lime recently slacked and ignited. The oil thus purified is colourless and limpid, and refracts the light strongly. Its smell differs from that of common volatile oil of bitter ahnonds. Its taste is acrid and aromatic. Its specific gravity is 1-043. Its boiling point is above 266°. Laurent, indeed, found it 356°.t It takes fire easily, and burns with a clear flame, emitting much smoke. It is not decomposed when passed through a red hot tube. In the air, or in xygen gas, whether dry or moist, it is converted into crystallized benzoic acid. The light of the sun hastens very much this transformation. It commences in a few minutes. When water and potash are present, we obtain a benzoate of that alkali. If these experiments are made in a glass tube, inverted over mercury, we perceive, by the ascension of the mercury, that the oxygen gas is absorbed. Nothing else is produced but benzoic acid during this transformation of the oil. It is not altered by the anhydrous fixed alkalies ; but when heated in contact of air with hydrate of potash, benzoate of potash is formed, and hydrogen gas disengaged. If we put the oil in contact with an alcoholic solution of hydrate of potash, or into absolute alcohol, saturated with ammoniacal gas, it dissolves readily, and there is formed (if air be excluded) a ben- zoate, which precipitates in large brilliant crystals, as soon as potash is added. When water is added, the salt dissolves, and an oil separates, which possesses the properties of oil of bitter almonds. This oil dissolves, without alteration, in concentrated nitric and sulphuric acids. When the sulphuric acid solution is heated, it becomes reddish-purple, then blackens, and sulphurous acid is disengaged. This oil was analyzed by Liebig and by Laurent, by means of oxide of copper, and its constituents were found to be Carbon Hydrogen Oxygen * Ann. (le Cliim. ot de Plijs. xliv. 353. Liebig. Laurent. 78-44 5-74 15-82 78-28 5-42 16-30 100-00 loot t Ibid. Ix. 219 I Ibid. f ! BENZOYL. C03 These numbers correspond with 14 atoms carbon = 10*5 or per cent. 79*26 6 atoms hydrogen = 0*75 — — 5*66 2 atoms oxygen =2 — — 15*08 13*25 100*00 It is easy, from our knowledge of the constituents of volatile oil of bitter almonds, and of benzoic acid, to explain what happens during the conversion of tlie oil into the acid. The oil is . . . C* H« O^ Benzoic acid . . . C* IV O- So that the oil contains 1 atom more of hydrogen, and 1 atom less of oxygen, than the acid. 2 atoms of oy gen are absorbed, the one unitf'r with 1 atom of hydrogen, and forms water, while the other comumos with (C" H"* C), and converts it into benzoic acid. Qn J-J5 Q2 n^ust be the base of benzoic r.cid, and the oil must be this base combined with an atom of hydrogen, or it must be a hydret of benzoyl ; for by this name Wiihler and Licbig have dis- tinguished the base of benzoic acid. SECTION I. — OF BENZOYL. M. Laurent obtained benzoyl in an insulated state, by passing a current of chlorine gas through benzoin,* taking care to keep it in fusion while this gas was passing : muriatic acid was formed, and benzoyl disengaged. He purified it by dissolving it in alcohol, and crystallizing it.f Thus obtained, it is slightly yeliow, destitute of taste and smell, insoluble in water, very soluble in alcohol and ether, fr'^m which it crystallizes in regular six-sided prisms, terminated by three pentagonal faces, indicating a rhomboid for the primitive form. Its b'stre is vitreous. When ground between the teeth it gives a disr seable sensation, like that of sulphur, under the same circumstances. It is fusible, and may be volatilized without decomposition. It becomes solid when cooled down to about 190°. On platinum foil it burns with a red flame, giving out smoke. Sulphuric acid dissolves, and water precipitates it from its solution. When heated with potassium it melts, and is a little altered. On increasing the temperature, there is a disengagement of light, accompanied by a violet vapour, and the deposition of charcoal. Potash ley does not alter it, even in a boiling heat, but an alcoholic solution of potash acquires a blue colour, and the benzoyl disappears, if we continue the boiling. It was analyzed by M. liaurent who obtained ~ 79*6 1 or 14 atoms = 10*5 or per cent. 80 5 rtoms = 0*625 — — 4*76 2 atoms = 2*000 — — 15*24 Carbon Hydrogen 4*91 or Oxygen 15*48 or 100*00 1.3*125 100 Precisely the composition assigned to it by Wiihler and Liebig. * Sec it described in a subsequent part of this Chapter. .... f Ann. do Chim. et de Thys. lix. 402. rt.. 004 UENZOYL AND ITS COMPOUNDS. li CM H» O^ QU H' O^ + H CM H» O' + H QU H^ O-! + QU H'^ 0'^ + Chl CH W O^ + Br C" IP 02 + Iod CM H» o=* + s CM H» 0^ + C» Az It will facilitate the account of the following compounds, if we state their composition here. Benzoyl ..... Hydret of benzoyl (or oil of bitter^ almonds) .... 3 Benzoin Benzoic acid .... Chloride of benzoyl Bromide of benzoyl Iodine of benzoyl Sulphuret of benzoyl . Cyanide of benzoyl Benzone . C'^H^O Benzine . C^ H^. Now,2(C«IF)+2(CO^)=C»^H»0»+0* Benzamide . C'MPO'^ + IP Az Benzimide . C* H'' O^ + Hj Az* ? Nitrobcnzide 2(C«rP) + Az O* Sulphobenzide 2(C«H"') + S 0» Azotobenzide 2(C«H»)+Az SECTION II. — OF HYDRET OF BENZOYL. This is the oil of bitter almonds, the properties and composition of which have been described at the beginning of this Chapter. SECTION III. OF BENZOIN. The substance which Wohler and Liebig have distinguished by the name of benzoin, was pointed out by Stange; but he merely mentioned its external characters. It has been noticed by some systematic writers under the name of camphoride, or camphor of oil of' bitter almonds. It is formed in certain circumstances in the oil of bitter almonds. MM. Wohler and Liebig obtained it accidentally, while rectifying oil of bitter almonds with caustic potash, and they got a great quantity of it by leaving for some weeks oil of bitter almonds in contact with a concentrated solution of caustic potash. When ben- zoin is obtained in this manner, it has a yellow colour. By dis- solving it in boiling alcohol, and treating it with animal charcoal, and then crystallizing it two or three times successively, we obtain it pure and colourless. It forms transparent crystals in prisms, and having a splendent lustre. It has neither taste nor smell. It melts at 248° into a colourless liquid, which assumes the form of a crystalline solid body on cooling. When raised to a higher temperature it boils, and may be distilled over. It catches lire easily, and burns with a lively flame, emitting much smoke. It is insoluble in cold, but slightly soluble in hot water, and falls down when the liquid cools in small crystalline needles. It is more soluble in hot than in cold alcohol. It is neither acted on by con- riMitratcd nitric acid, nor by a concentrated solution of potash. Is, if we O Chi Br lod S C^ Az composition 'hapter. nguished by t he merely jcd by some mphdr of oil ter almonds, lie rectifying rot a great aWnonds in When ben- ,ur. By dis- mal charcoal, sly, we obtain a splendent 248° into a ine solid body loUs, and may with a lively ater, and falls ?s. It is more ed on by con- on of potash. CHLOUIDK Ol' HENZOYL. Gor* Sulphuric acid dissolves it, and the solution has a violet-blue colour, which becomes gradually brown, and assumes, when heated, a deep green colour. Sulphurous acid is disengaged, and the whole assumes the colour and consistence of tar. BVom the analysis of this substance by Wiihler and Liebig, it ap- pears to be isomeric with the hydret of benzoyl. They obtained Carbon 7H Hydrogen .... 5*7 Oxygen IG'3 lOO-O* Now, if the reader will turn to page 602 of this Chapter, and com- pare the analysis of hydret of benzoyl given there, with the pre- ceding numbers, he will be at once satisfied, tliat the constituents of both are the same. Yfit the properties of the two substances arc exceedingly different. When bromine is thrown on benzoin, the temperature rises, and a great deal of hydrobrom'" acid is disengaged. When we drive off this acid, and likewise any excess of bromine that has been added, we find the benzoin changed into a thick brown liquid, which has the smell of bromide of benzoyl, but does not become solid like that substance. Boiling water acts upon it exceedingly slowly. A boil- ing solution of caustic potash acts upon it with difficulty. When muriatic acid is added to this alkaline solution, crystals are de- posited, the nature of which has not been ascertained. Wiihler and Liebig attempted unsuccessfully to convert benzoin into oil of bitter almonds. When melted with hydrate of potash, it gave, as that oil does, benzoic acid, while hydrogen gas was disen- gaged. When treated with alcoholic solution of potash, it assumes a purple colour, and dissolves, and then separates again in a mass of crystalline plates. When treated with water, we obtain a milky liquid. If we heat it, and then allow it to cool, needle-form crystals are deposited, consisting of pure benzoin. SECTION IV OF OXIDE OF BENZOYL, OR BENZOIC ACID. This acid, which is benzoyl, combined with an atom of oxygen, has been described in a former Chapter. SECTION V. OF CHLORIDE OF BENZOYL. When chlorine gas is passed through oil of almonds, or hydret of benzoyl, much heat is evolved, the gas is absorbed, and muriatic acid gas is disengaged. When the evolution of this gas is at an end, the liquid has a yellow colour from an excess of chlorine ; but this excess is easily driven off by heat. The liquid is now pure chloride of benzoyl. , It is liquid and limpid like water. Its specific gravity is 1*196. It has a peculiar and very penetrating smell, which acts itrongly on ' It was analyzed by M. Laurent with the same result. See Ann. de Chim. et de Phys. lix. 402. i f 'I I I GOO BENZOYL AND ITS COMPOUNDS. i:(( t*ii ^. the eyes, and has sornc analogy to that of horse-radish. Its boiling point is higii. It takes fire, and burns with a clear flame with a green bordt.*r, emitting much smoke. When poured into water it falls to the bottom without dissolving. After remaining in water for a long time, or when the action is assisted by heat, it is decmnposed into crystallized benzoic acid and muriatic acid. It undergoes the same change when long ex- posed to a moist atmosjdiere. When chlorine gas is passed through a niixtiiro of hydret of benzoyl and water, the oil disappears, and the water is tilled with crystals of benzoic acid. Chloride of b(;nzoyl may be distilled oft' anhydrous barytes or chalk, without any alteration. When heated with an alkali and water, it gives immediately bciizoate of the alkali, and chloride of the base of the alkali. It was subjected to an analysis by Wohler and Liebig, who obtained Carbon ♦iO"()7 or 14 atoms = 1()"5 or per cent. 59*58 Hydrogen 3'74 or 5 atoms = 0*(J25 — — S-fiS Oxygen 10-84 or 2 atoms = 2'0 -- — 11-34 Chlorine 24-75 or 1 atom =4-5 — — 25-53 100 I7-G25 100-00 It Is, therefore, benzoyl united with an atom of chlorine, or chlo- ride of benzoyl. This chloride, when assisted by heat, dissolves sul])hur and phos- phorus, and, on cooling, these bodies areajiain separ.atod in crystals. It may be mixed in every proportion with bisulphuret of carbon. When placed in contact with perchloride of phosi)horus it becomes hot, while protochloride of phosphorus is formed, together with an oily body, having a penetrating smell. Chloride of benzoyl may be mixed in all proportions with alcohol. This mixture becomes gradually hot, and at last boils, while abundance of muriatic acid is disengaged. It we add water after all mutual action is at an end, a heavy oily substance separates, having an aromatic odour. If we wash it with water, and then distil it oft" chloride of calcium, we obtain it in a state of purity. This sub- stance is benzoic ether, composed, as MM. Wohler and Liebig have shown, of 1 atom benzoic acid C'^ H'' O^ + C* W O or an atom of sulphuric ether. For they obtained, when they sub- jected it to analysis. Carbon . . 72-529 = 18 atoms Hydrogen . . 6*690 =10 atoms Oxygen . . 20*781 = 4 atoms 100-000 SECTION VI. OF imOMIDE OF BENZOYL. This compound is formed when hydret of benzoyl is mixed with CYANODIDE OF BENZOYL. f)07 bromiiio. Heat is evolved, niul tliick vapours of hydrobromic acid are exhaled. \iy heatin«? the mixture, the excess of bromine and th«^ hydrobrouiic acid nro driven otf, and bromide of benzoyl remains in a state of purity. This bromide constitutes a soft, half li(|uid mass, composed of larpo crystalline plates, luivinfj a brownish colour. It melts when gently heated into a yellowish-brown liquid. Its smell is similar to that of the chloride of benzoyl; but much weaker, and slightly aromatic. In the air it smokes slightly ; but the vapours be- come very copious if we heat it. It catches fire when exposed to a flame, and burns with a strong light, but emitting much smoke. Water decomposes it slowly. When heated under water it assumes the form of a brownish oil. Hy long boiling it is decom- posed into hydrobromic acid and crystallized benzoic acid. This shows us that it must be a compound of I atom benzoyl . . C'^ H'^ 0» and 1 atom br(tmine. . . Br It dissolves readily in alcohol and other without undergoing decom- position, and separates from them by evaporation in a mass of crystals. SKCTION Vll. — OF lODinn OF UENZOVL. This compound cannot be formed by mixing hydret of benzoyl and iodine together ; but it is readily obtained by boating a mix- ture of iodide of potassium sind chloride of benzoyl, it distils over in the form of a Irown lifjuid, which, or 13 ntonis = 9'7.'> or per cent. H4'72 Mydrojren 5*()r) or T) atoms = 0'(i'25 — — ty-i'.i Oxygen 7*00 or 1 atom =1 — _ 8'71) 11'375 lOO-OO These numbers d(» not ajjrco very closely with the analysis, but they nuist be tluj true onus, if benzoic ucitl be decomposed into benzone and carbonic acid. For Henzoic acid, is . . C'« H" 0» And subtractinjr carbonic acid C O' Remains for benzone C" IP () SECTION XI. — OF UENZIN. Mitscherlich observed, in 1833,* that when benzoic acid is mixed with 3 or 4 times its weijifht of slacked lime, and the i";xture dis- tilled, we obtain pure bicarburetted hydrogen, Jind nothing ciso, while the lime is converted into a carbonate. To the bicarburet of hydrogen, thus obtained, ho has given the name of bevzin.^ Benzin is a limpid and colourless liquid. It has a peculiar s .• 11, and its specific gravity is 0*83. It boils at 187", and when sui • rounded with ice congeals into a crystalline mass, which melts vvheu heated to 44°^. It dissolves readily in alcohol and ether, but in very small quantity in water, though it conununicfitcs to that liquid a strong smell. It is not dissolved nor altered by sulphuric acid, even though distilled over with it. Muriatic acid and the other powerful acids are equally inert. Chlorine gas has little action on it m the dark ; but when light is admitted, thick clouds of muriatic acid appear, and crystals, together with a soft matter, are formed. The soft substance dissolves easily in ether, while the crystals are much less soluble, so that in this way they may be separated from each other. Bromine decomposes benzin. But iodine dissi Hc" in it without decomposing it. Mitscherlich analyzed it, anu 1" und the consti- tuents Carbon 91*3 or 2 atoms = 1'5 or per cent. 9 1 '38 Hydrogen 7-7 or I atom = 0-125 — — 7*62 1-C25 99-00 It is clear that the benzin of Mitscherlich is the same with the bicarburet of hydrogen of Faraday,t both in its properties and com- position. He found the density of its vapour to be 2*77. It is ob- vious from this, that it is composed of * Ann. do Chim. ct de Phys. Iv. 42. \ Altered by Liobig to Benzol. See Ann. der Pharmacie, ix. 43. X Described in the Chemistry of Inorganic Bodies, i. 202. 2 u 610 BENZOYL AND ITS COMPOUNDS. t h:; 6 volumes carbon vapour 3 volumes hydrogen gas Sp. gravity. = 2-5000 = 0-2083 2-7083 Condensed into 1 volume. So that it is a compound of G atoms carbon . . . =: 4-5 3 atoms hydrogen . . = 0-375 And its atomic weight is 4-875 Crystallized benzoic acid contains an atom of water, and is, therefore, C* W O* It may be resolved into 2 atoms benzin . . C'^ H^ 2 atoms carbon acid . C^ O* Thus we have a new way in which benzoic acid may be resolved into two new and simpler substances. SECTION XII. — OF NITROBENZIDE. This is a name given by Mitscherlich, to a substance formed when nitric acid is made to act upon his benzin. Benzin and nitric acid of moderate strength, have so little action on each other, that they may be distilled together without altering the nature of the benzin. But when benzin is heated with fuming nitric acid, action takes place with the disengagement of heat. The benzin should be added to the hot acid in small quantities at a time. The resultin<; compound dissolves completely in the hot {icid ; but when the liquid cools, a portion separates and swims upon the surface. When water is added, this portion falls to the bottom of the liquid, because it is heavier than water. If we wash this substance and distil it again, we obtain it in a state of purity. It is the nitrobenzide of Mitscherlich. It is a light yellow liquid, having a very sweet taste, and a peculiar odour, intermediate between that of oil of bitter almonds, and oil of cinnamon. Its specific gravity at 59° is 1-209. It boils at 415°, and may be distilled over without alteration. At 37°^ it becomes solid, and crystalline needles make their a])pear&,nce in it. It may be distilled with nitric acid without any alteration. When mixed with dilute nitric acid, it may also be distilled over unaltered, if the temperature be sufficiently high. But concentrated sulphuric acid, when boiling hot, decomposes it, with the disengagement of sulphurous acid. Chlorine and bromine, have no action on it in a liquid state. But when passed *hrough a red hot tube along with chlorine, muriatic acid is formed. When heated with potassium, it detonates and breaks the vessel. An aqueous solution of potash has little action on it. An alcoholic solution of potash does not act at the ordinary temperature, but when boiled with it, the liquid assumes .su - liq -.. VVI of . bo I SULPHOBENZIDE. 611 er, and is, f be resolved 3 formed wben 50 little action thout altering d with fmnmg nent of beat. 11 quantities at ely in the hot u(i swims upon ( to the bottom we wash tins "of purity. It Land a peculiar londs, and oil of V boils at 415°, [70! it becomes in it. .ration. When over unaltered, trated sulphuric Isengagcment of laction on it in a tube along with ith potassium, it ion of potash has ^ does not act at ic liquid assumes a blood-red colour. When distilled it gives a red matter, which is solid at the common temperature of the atmosphere. Ammonia does not act upon nitrobenzide. The mean of two analyses, by M. Mitscherlich, gave for its con- stituents Carbon 58*53 or 12 atoms = 9 or per cent. 58*54 Hydrogen 4*08 or 5 atoms = 0'G25 — — 4'06 Azote 11-02 or 1 atom =1-75 — — 11-38 Oxygen 25-99 or 4 atoms = 4-00 — — 26-02 15-375 100-00 It is probable that the true quantity of hydrogen is 6 atoms. In that case, it would be a compound of 2 atoms benzin, and 1 atom of nitrous acid. For 2 atoms benzin are . . . C"* H" 1 atom nitrous acid ... Az O* C'2 H« Az O* The specific gravity of its vapour was found by Mitscherlich to be 4-40, or from that to 4-35. Now if we consider it as consisting of one volume of benzin vapour, and half a volume of nitrous acid vapour condensed into one volume, we have Sp. gravity. 6 volumes carbon vapour . =2-6 3 volumes hydrogen gas . = 0-2083 ^ volume azotic gas . . = 0-4861 1 volume oxygen gas . =1-1111 4-4055 A specific gravity almost coinciding with that found by Mitscherlich.* SECTION XIII. OF SULPHOBENZIDE. When small quantities of benzin are added to the sulphuric acid of Nordhausen, as long as it continues to be dissolved, and then water is poured into the liquid, there separates a crystalline sub- stance, so small in quantity that it scarcely amounts to 2 per cent, of the benzin employed. If we saturate the liquid with car- bonate of barytes, and throw down the barytes by sulphate of copper, and concentrate, we obtain cr/stal? composed of oxide of copper, and the acid of the soluble salt of barytes ; that is to say, of henzo- sulphate of copper. If, instead of this, we plac3 benzin in contact with anhydrous sulphuric acid, the acid is not decomposed, and there is conse- quently no disengagement of sulphurous acid. We obtain a thick liquid which dissolves entirely in a little water. But if we mix it with a great deal of water, there separates a much greater quantity of the crystalline substance, as it amounts to 5 or 6 per cent, of the benzin employed. * Mitscherlich J Poggondorf's Aiinalen, xxxi. 225. .^1 II w •if f) "p. I It !. : . 612 BENZOYL AND ITS COMPOUNDS. 'I ■ > J ;> :«*• ' ■> I If we saturate the acid with barytes, and decompose the new salt by means of sulphate of copper, we sometimes on evaporating, this liquid, obtain none, sometimes only a little of benzosulphate of copper ; but a crystalline powder separates when we evaporate to dryness. We obtain the same substance, when we treat the crystalline matter with hot and concentrated sulphuric acid. The crystalline substance being but little soluble in water, may be completely freed from all excess of acid by washing. To purify it completely, we have only to dissolve it in ether, let it crystallize, and distil over the crystals. It is soluble in alcohol and ether, and may be obtained from these solutions in regular crystals. At 212° it melts into a transparent and colourless liquid, and boils at a temperature between the boil- ing points of mercury and sulphur. It is colourless and destitute of smell. It is insoluble in alkalies ; but dissolves in acids, and is precipitated by water. When heated with sulphuric acid, it combines with it and forms a peculiar acid, which gives a soluble salt with barytes. The other acids do not alter it. It detonates when heated with saltuetre or chlorate of potash. At the ordinary temperature, chlorine and bromine have no action on it, but when it is heated to the boiling point, these two substances decompose it, and chloride of benzin is formed. Mitscherlich analyzed this substance, and found the constituents : Carbon 66*18 or 12 atoms = 9 Hydrogen 4*55 or 5 atoms = 0-625 Sulphuric acid 35*42 or 1 atom = 5 106-15 14*625 Or probably 2 atoms of benzin combined with 1 atom of sulphuric acid.* ^h'l SECTION XIV. — OF AZOTOBENZIDE. This naw.e. has been given by Mitscherlich to a substance obtain- ed by distilling a mixture of nitrobenzide and lime. But the best way of forming it is to dissolve nitrobenzide In alcohol, and mix it with an alcoholic solution of potash. When heat is applied to this mix- ture, a raj 'd action takes place. A salt of potash is formed, differ- ent from saltpetre, and a compound, upon which a farther addition of potash has no action. When this substance, which is red, is distilled, a red liquid passes over, which, on cooling, shoots into large crystals. If these crystals be dried upon blotting paper, dis- solved in ether, and crystallized again, they constitute azotohenzide in a state of purity. It dissolves readily in ether and alcohol, and easily crystallizes from both solutions. Boiling water dissolves it very sparingly, yet it acquires a red colour, and becomes muddy on cooling. It is very little soluble in ammonia, concentrated potash ley, or strong muriatic * Poergcmiorf's Annalen, xxxi. C28. e new salt atingj thia of copper; dryness, line matter water, may To purify crystallize, L from these transparent ;en the boil- ; in alkalies ; ^hen heated eculiar acid, acids do not • chlorate of bromine have int, these two ned. constituents: 55 HYDnOSPIROILIC ACID. 618 n of sulphuric jstance obtain- But the best and mix it with ;d to this mix- 'ormed, diffev- rther addition lich is red, is ig, shoots into ing paper, dis- te azotobenzide sily crystallizes sparingly, yet mg. It is very strong muriatic acid. It dissolves in concentrated nitric and sulphuric acids, and is again precipitated from them by water. When the sulphuric acid solution is heated, decomposition takes place, charcoal being depo- sited, and sulphurous acid given out. It may be distilled unaltered from potash ley or quick lime. It melts when heated to 141)0, boils at 379°, and may be distilled over without decomposition. It was subjected to an analysis by Mitscherlich, who obtained Carbon 79*16 or 12 atoms =9 or per cent. 79*12 Hydrogen 5*45 or 5 atoms = 0*625 — — 5-49 Azote 14-95 or 1 atom =1-75 — — 15-39 99-56 11-375 100-00 So that it differs from nitrobenzin, in wanting the 4 atoms of oxygen which exists in that substance. It is probably a compound of 2 atoms of benzin and 1 atom of azote.* CHAPTER III. OF SPIROIL AND ITS COMPOUNDS. Spiroil is the supposed base of the volatile oil extracted from the flowers of the spiraea ulmaria, by M. Pagenstecher of Berne, who determined its properties, and showed that it possessed acid char- acters. M. Lowig of Zurich has analyzed this oil, and shown that it is a compound of C*'^ H^ O*, with an atom of hydrogen. This compound, C* H^ O*, has not been obtained in a separate state, but it has been combined with oxygen, chlorine, bromine, iodine, and hydrogen, and shown to form definite compounds with each.v l^o this hypothetical base Liiwig has given the name of spiroil.f The compounds which it forms, so far as they have been examined, will be described in the following Sections : — SECTION I. or HYDKOSPIROILIC ACID. The volatile oil of spircea ulmaria, or hydrospiroilic acid, may be obtained by distilling the fresh flowers of the plant along with water. A quantity of water is allowed to come over, abo'it equal to the weight of the flowers employed. The product of this distillation is distilled anew, till about ^t\\ part of it pass into the receiver. We obtain, in this way, a strong aqueous solution of the oil, and a small quantity of the oil itself. It is heavier than water, has a light-yellow colour, and has the same smell as the flowers of the spircea ulmaria, only much stronger. It may be mixed in all proportions with alcohol and ether. It is * Mitscherlich ; Poggendorfs Annalen, xxxii. 225. f Poggcndorfs Annalen, xxxvi. 283. I H 614 SPIROIL AND ITS COMPOUNDS. ''I soluble also in water, but less so than in the two other liquids. Its taste is hot and acrid. Litmus paper is rendered first green, and then white, by the vapour of the oil, while distilling. Tincture of litmus is rendered first red by the aqueous solution of the oil, then whitened, retaining a slight shade of green. It is combustible, and burns with a lively .;.ime, giving out smoke. When this oil is passed through a red hot tube, filled with frag- ments of iron, we abta'a no ammonia nor hydrocyanic acid ; nor is any sulphuret of Iron formed. It may be evaporated completely without undergoing any alteration. It becomes solid when cooled down to 4°. It boils at 185°, at which temperature it may be dis- tilled over without leaving any residue. It combines readily with the alkalies and alkaline earths, and forms with them salts insoluble, or but little soluble. Concentrated sulphuric acid chars it. Chlorine and bromine immediately decompose it ; muriatic acid or hydrobrornic acid being formed, and chloride or bromide of spiroil. Nitric acid, if not too strong, converts it into spiroilic acid. But concentrated nitric acid changes it into a yellow butyraceous mass, very volatile, and having a bitter taste. The anhydrous oil was analyzed by Lowig in the usual way, by means of oxide of copper. He obtained Carbon 65*26 or 12 atoms = 9 or per cent. 65*45 Hydrogen 5'55 or 6 atoms = 0*75 — — 5*46 Oxygen 29*19 or 4 atoms = 4 — — 29*09 100*00 13*75 100 If we agitate hydrated oxide of copper in an aqueous solution of the oil, taking care that there be an excess of oil, we obtain a green- coloured matter, which may be dried in the temperature of 320°, without undergoing any change. For the oil may be still separated from it unaltered by means of an acid. M. Liiwig subjected this compound to analysis, and obtained Carbon 50*78 or 12 atoms = 9 or per cent. Hydrogen 3*44 or 5 atoms = 0-625 — — Oxygen 23*09 or 4 atoms = 4 — — Copper 22-69 or 1 atom =4 — — 51*06 3*54 22*70 22*70 100*00 17*625 100 If we compare this constitution with that of the hydrospiroilic acid, we ])erceive that the only difference between the two is tlie substitution of an atom of copper in the latter compound for an atom of hydrogen in the former. This is what has induced M. Liiwig to consider the acid or oil as a compound of 1 atom hydrogen with the compound base C'^ H° O*, to which he has given the name of .spiroil. As a farther corroboration of the justness of his views, M. Liiwig made the following experiment : — Ilydrospiroilicacid was placed in | contact with potassium over mercury. The temperature rose a HYDROSPIROILIC ACIU. G15 quids. Its n, and then •e of litmus ; oil, then iistible, and i with frag- icid ; nor is completely when cooled may be dis- I earths, and and bromine lie acid being jid, if not too cd nitric acid ,e, and having usual way, by nt. 65-45 _ 5-46 _ 29-09 100 sous solution of obtain a green- •ature of 320°, ! still separated r subjected this l ;ent. 51-06 ' _ 3-54 - 22-70 I ^ 22-70 100 ; le hydrospiroilic n the two is the lound for an atom :ed M. Liiwig to ; ydrogen with the ven the name of views, M. Linvig icid was placed in mperatuvc roi^o a little, and hydrogen gas was evolved, while a spiroilide of potassium was formed. When this spiroilide is treated with muriatic acid, we obtain chloride of potassium, and the oil is separated unaltered. When this experiment is made at the common temperature of the atmosphere, the action is gentle ; but if we apply heat, it is so ac- celerated, that flame is produced. No charcoal is deposited, and the hydrogen is perfectly pure. If the oil employed be not quite dry, a little hydrogen is evolved the instant the potassium comes in con- tact with it, but this disengagement speedily stops. If we now ap- ply heat, the disengagement of hydrogen begins again, and is dis- charged in the same way as when anhydrous oil is employed. Let us now attend to the characters of the salts formed by the combination of hydrospiroilic acid with the bases. 1. Hydrospiroilate of ammonia. If we pour a concentrated solu- tion of ammonia upon hydrospiroilic acid, the temperature speedily rises, and the whole becomes a solid mass of hydrospiroilate of am- monia. By washing this salt with alcohol, we may deprive it of water, and of any excess of acid that it may contain. It has a weak aromatic smell, analogous to that of the rose. It has a yellow colour, and is destitute of taste. It is almost insoluble in water, and but little soluble in cold hydrous alcohol. But absolute alcohol dissolves it in considerable quantity, both cold and hot. When the boiling alcoholic solution is allowed to cool, the salt crystallizes in fine transparent needles, usually collected in tufts, and having a light yellow colour. When this salt is kept moist in close vessels, it gradually undergoes decomposition. It becomes first black, then semifluid, ammonia is disengaged, and a strong smell of roses is perceptible. When heated to 212°, it undergoes no alteration. At 239°, it melts like wax, and is volatilized unaltered in a yellow vapour, when heated a few degrees above its melting point. Acids decom- pose it, uniting with the ammonia, while the oil is separated unal- tered. M. Linvig analyzed it, and found its constituents to be Ammonia . . . 13-52 or 2-125 Hydrospiroilic acid . 86-48 or 13-59 100-00 According to this analysis, the atomic weight of hydrospiroilic acid is 13-59. Now, this approaches very near to 13-75, wliich is the atomic weight deduced from the direct analysis of the oil. It is obvious that the salt is a compound of 1 atom acid and 1 atom ammonia. 2. Spiroilide of potassium. This compound is obtained when potassium is placed in contact with hydrospiroilic acid, and a gentle heat applied. Or it may be formed by placing in contact aqueous solutions of the acid, and of potash. It is with dlflSculty soluble in water. If we evaporate its solution slowly, we obtain small pris- matic crystals, of a straw-yellow colour. When exposed to the air it is decomposed, attracting moisture and carbonic acid. In dry ves- V- j! Mm hMM 616 SPIBO?L ANn ITS COMPOUNDS. • i I ' sels it may be kept a long time without decomposition. During its decomposition the smell of roses becomes manifest. At last nothing remains bu< carbonate of potash. This spiroilide is coraposed of 1 atom spiroil . . . 13 0:15 1 atom potiiisium ... 5 18"i25 3. Spiroilides of sodium, calcium., and bariim, resen'le closely the spiroilide (^f potassium, onlj' the two jp.st are lesf soluule in water. 4. Spiroilide of magnemfia may be >brmed by agitating together the aqueous solution of hydrospiroilic acid and hydrate of magnesia. It is a light yellow almost ii)S!>luble pov-^der. 5. Spiroilide of iron. Protochloride of iron is not altered by aa niiueoif^ solution of hydrospiroilic acid. V lien uramoaia is «.i led, a dark ^ u.i]e<^ Muo precipltatr; ialls. 6. Sesq^mpii:ulidr. of iron. Perchloride of iron, when mixed with the aqueo". .rlution of hydrospiroilic acid, gives it a fine dark-red cherry-red <;ciour, witiiout occasioning any procipitate. If we ex- pose the raixture to the air, it gradually loses its red colour, and there remains a pure solution of sesquichloride ui' iron. If we add a little more solution of hydrospiroilic acid, th( cherry-red colour ,igain appears. 7. Dispiroilide of copper. Bichloride of copper is not altered by an aqueous solution of the oil. A small addition of ammonia throws down a light brown precipitate. 8. Spiroilide of copper. We obtain this compound when we agitate the aqueous solution of the oil with hydrate of copper. The hydrate speedily loses its blue colour, and becomes green. If we mix a solution of sulphate of copper with spiroilide of potassium, a bulky precipitate falls, which separates very slowly, and puts on an imperfect appearance of crystals. 9. Spiroilide of zinc. When oxide of zinc is agitated with a so- lution of the oil in water, it rapidly combines with it. The water assumes a yellow colour. If we evaporate under the air pump, we obtain a yellow powder. Sesquichloride of iron renders the liquid cherry-red. 10. Spiroilide of lead. Pure oxide of lead does not form a spi- roilide when placed in contact with an aqueous solution of hydro- spiroilic acid. But the hydrated oxide, when agitated with that liquid, is converted into small shining scales, constituting a light yellow powder of spiroilide of lead. 1 1 . Spiroilide of mercury. Red oxide of mercury does not form a spiroilide when agitated with the aqueous solution of the oil. But we obtain it when we mix together concentrated solutions of corrosive sublimate and hydrospiroidate of ammonia. The precipi- tate is bulky, composed of flocks, and has a light straw-yellow colour. 12. Spiroilide of silver. Oxide of silver dissolves partially in the aqueous solution of the oil. The solution has a yellow colour, and CHLORIDE OF SPIROIL. 617 during its it nothing closely the 3 in water. ig together magnesia. •ered by aa la is «..'le'... : [ (i> (J20 .SUGARS. Fuming nitric acid acts violently on spirollic acid. A yellow bitter tasted substance is produced, which gives a yellow colour to the saliva, the skin and the nails. It is fusible, and may be distilled over, and has a strong smell of fresh butter. Oxalic acid is formed at the same time with this yellow substance. CHAPTER IV. OF SUGARS. The term sugar, in common language, is applied to various sub- stances, all of which are characterized by their sw, vol. V. [). 5G. § See Falconer's Sketch of the History of Sugar, Manchester Memoirs, iv. -l'J\ ; and Mosleys History of Sugar. ai til COMMON SUGAR. 621 \. yellow colour to i diatilled is formed arious sub- te. In tliis inces, all ot property in irticle in tlio m at a very But Europe conciucsts of n I'liny* aud solid, wliich his statement ) the ancients 3 so imperfect J introduction 3 consumption enetians, who thcrn parts of [ | It was not luction of the liat its use in hern parts of ar is produced ' it is produced plants indeed America, how- igar maple, but es, c. 74. Reg. Goltingensis, lestcr Memoirs, iv. During the war between Hoi irte and Great Hritain, the ex- traction of sugar from the heet root was introduced into France. This manufacture still continues. In the year 18*27, the quantity of beet sugar made in France was 'ijJJ.'iOjOOO lbs.* 1. Tlie method of making sugar practised in Indostan is exceed- ingly simple, and recjuires little or no expensive apparatus. The soil chosen is a rich vegetable mould, in such a situation that it can bo easily watered from tiu^ river. About the end of May, wiien the soil is reduced to the state of soft nmd, either by rain or artilicial watering, slips of the cane, containing one or two joints, are plantc^l in rows about four feet from row to row, and eiiihteen inches asunder in the rows. When they have grown to the height of two or three inches, the earth round them is loosened. In August small trenches are cut through the field to (U'ain oft" the rain, if the season ])rovo too rainy ; and to water the plants, if the season prove too dry. From three to six canes spring from e.'ich slip set. When they arc about three feet high, the lower leaves of each cane are carefully wrapped round it; and then the whole belonging to each slip arc tied to a strong bamboo eight or ten feet high, and stuck into the earth in the miiUUe of them. Tiiey are cut in January and Feb- ruary, about nine months after the time of planting. They have now reached the height of eight or ten feet, and the naked cane is from an inch to an inch and a quarter in diameter. They have not flowered. When this hapjjens, the juice loses much of its sweet- ness. The newly cut canes are put through tlie rollers of a mill, and their juice collected into large iron boilers, where it is boiled down smartly to a proper consistence, the scum being carelessly taken off. The fire is then withdrawn, and the licpiid by cooling becomes thick. It is then stirred about with sticks till it begins to take the form of sugar, when it is put in mats made of the leaves of the palmira tree {borassus Jlahelliformis), and the stirring continued till it is cold.f This process yields a raw or powdered sugar ; but it is clammy, and apt to attract moisture from the atmosphere, because the acids in the juice have not been removed. By the ad- tlition of quick lime to the juice in the proportion of about three . spoonfuls to every 14 gallons, the sugar loser this property. The impure sugar prepared by this method is called jag- ry. Every three quarts of juice, or every six pounds, yield about one jM-und of sugar. From an acre of ground about 5000 pounds if sugar, and consequently about 30,000 pounds of juice are obtained. 2. In the West India islands the raising of sugar is much more expensive, and the produce much less, owing to the high price of labour ; or, which is the same thing, to the nature of the labourers, and to the inferiority of the soil. The juice extracted by passing the cane twice between iron rollers is received in a leaden bed, and * Ann. de Chim. et do Phys. xxxvii. 53. t See Dr Roxburgh's Account of the Hindoo Method of Cultivating the Sugar Cane, Repertory, ii. 425, Second Series ; and Tennant's Indian Recreations, ii. 31 , C22 SUiiAKS. :' .< I , ' -i . i' (I thence conducted into a receiver. Hero it cannot bo . i v >d to Htand above 20 minutea wlthont be^inninjj; to ferment, 'rheretbre, aa Hoon us collected, it iit rnn into ii Hut <;opper caldron called u clarijier, capable of holdinji; 40()^'allona or more. Here it is mixed with a quantity of lime. The maximum used is a nint of lime to every hundred gallons ; but in fjeneral much less will serve. Fire ia immediately applied, and the juici^ heated to tlw temperature of 140°. The tire ia then extinfrnished. A thick viscid scum forms upon the top, which remains unbroken, and the clear liquid is drawn off from \nuler it by a cock or syphon, ainl introduced into a large copper boiler. Here it is boileil brisklv ; the scum, as it forma, bemg continually removed by large skimmers. When the bulk of the li I i f 628 SUGARS. 1:1 e'! ' which contains hyposulphate of lime in solution. When sugar is long boiled with dilute sulphuric acid, it is converted into sugar of grapes, or that species of sugar into which starch is converted by the same process. By nitric acid it is converted into oxalhydric and oxalic acids. 480 grains of sugar, treated with 6 ounces of nitric acid, diluted with its own weight of water, and cautiously heated, separating the crystals as they formed, yielded 280 grains of oxalic acid. So that 100 parts of sugar yield by this treatment 58 parts of oxalic acid.* When sugar is dissolved in a concentrated solution of arsenic acid, the liquid becomes gradually red, then purple, and finally brown, while at the same time a portion of the sugar is converted into sugar of grapes. Muriatic acid acts upon sugar like sulphuric acid. When chlo- rine or muriatic gas is passed over sugar in powder, it is absorbed, and the sugar is converted into a brown liquid substance, which contains muriatic acid, and which smokes in the air. When chlorine gas is passed through a solution of sugar, it transforms it into oxalhydric acid, while the chlorine is converted into muriatic acid. If, to a solution of sugar, we add 3 per cent, of oxalic or tartaric acid, the sugar loses the property of crystallizing, and does not re- cover it, though V e saturate the acid with carbonate of lime or of lead.f But the action of acids on sugar has lately been investigated by MM. Malagutti ai.d Boucbardat.J They have ascertained that acids, in general, whether organic or inorganic, even when very dilute, act upon sugar in t.i same manner when assisted by heat. They first convert it into incrystallizable sugar, then into sugar of grapes, then into incrystallizable sugar, then into ulmic acid ; and, finally, if atmospheric air be present, into ulmic and formic acids. After cane-sugar has been changed into sugar of grapes, the con- version of it into ulmic and formic acids, goes on even at ihe common temperature of the atmosphere. A very minute quantity of acid acts in the same way, but more slowly. The more concentrated the acid is, the more rapid is the action. The presence of atmospherical air is necessary, otherwise sugar cannot be converted into formic acid. 14. Sugar combines with the acidifiable bases. When dissolved in a ley of caustic potash it loses its sweet taste, and leaves, when evaporated, a mass, which is insoluble in alcohol, and which, when the potash is neutralized with sulphuric acid, yields sugar unaltered, and still soluble in alcohol, § When we introduce sugar in fine powder into a glass filled with ammoniacal gas, and standing inverted over mercury, and allow it to reuiain as long as it continues to absorb the gas, it diminishes in * Cniickshanks, Rollo on Diabetes, p. 460. f Vogel, Ann. di; Chim. Ixxi. 95. % J*'"'", ile Pharmacie, xxi. 440, and 627. § Cruickshanka, Rollo, on Diabetes, p. 460. COMMON SUGAU. 629 n sugar is ;o sugar of nverted by lalic acids, id, diluted separating acid. So s of oxalic of arsenic and finally 3 converted iVhen chlo- s absorbed, ince, wbich len chlorine rms it into riatic acid. B or tartaric does not re- if lime or of estigated by tained that when very ted by heat, nto sugar of i acid ; and, 'ormic acids. )es, the con- ihe common of acid acts ated the acid tmospherieal L into formic len dissolved leaves, when which, when ar unaltered, iss filled with ,nd allow it to diminishes in i. 440, and 027. bulk, becomes coherent, compact, pnd soft, so that it can be easily cut with a knife, and gives out an ammoniacal smell. According to Berzelins, to whom we are indebted for this experiment, this com- pound consists, by weight, of Sugar 90'28 Ammonia . . . . 4*72 Water 5-00 100-00* Now, these numbers are proportional to Ammonia . . 2' 125 or 1 atom Water . . 2*25 or 2 atoms Sugar . . . 40*64 It will appear afterwards, from the analytical experiments on the composition of sugar, that its atomic weight is 20*25 ; 40*64, therefore represent 2 atoms of that substance. Consequently this combination of sugar and ammonia must consist of = 40*5 or per cent. 90*26 = 2*125 _ — 4*73 2 atoms sugar 1 atom ammonia 2 atoms water = 2*25 — 5*01 44*875 100*00 When this compound is exposed to the air the ammonia flies off, and the sugar remains unaltered. When lime Is added to a solution of sugar in water, and the mix- ture boiled for some time, a combination takes place. The liquid still, indeed, retains its sweet taste ; but it has acquired also a bitter and astringent one. A little alcohol added to the solution produced a precipitate in white flakes, which appeared to be a compound of sugar and lime. Sulphuric acid precipitated the lime in the state of sulphate, and restored the original taste of the sugar. When the compound of sugar and lime was evaporated to dryness, a semi- transparent tenacious syrup remained, which had a rough bitter taste, with a certain degree of sweetness.f It would appear from the observations of Mr Daniell, that lime has a tendency to convert sugar into gum. When raw sugar from the West Indies is kept for some time in this country, it is apt to assume a clamminess, with the soft feel of flour. In this slate it is called weak sugar. Mr Daniell is of opinion that this change is occasioned by the action of the lime (always present in raw sugar) upon the sugar .$ From the experiments of Mr William Ramsay, it appears that sugar f-'.cilitates and increases the solubility of lime and strontian, and forms a combination with them. But barytes seems to act with more energy, and to occasion a partial decomposition of the sugar. For on endeavouring to dissolve it in syrup it was constantly * Berzelius, Traite de Chimie, v. 239. f Cruickshanks, liollo on Diabetes, p. 460. X Quarterly Jour. vi. 32. 'i ''■*M i » f »i 630 SUGARS. ■"' ik i ' rli ! i : -T II J ■} converted into a carbonate, and very little in consequence dis- solved.* When a solution of sugar is digested on oxide of lead, the oxide is gradually dissolved, but after a certain interval of time a light white powder makes its appearance. This powder is a compound of sugar and oxide of lead. It is white, light, tasteless, and insoluble in water. According to Berzelius, to whom we are indebted for our knowledge of it,t its constituents are as follows : — Sugar . 41-74 or 10-03 Oxide of lead 58-26 or 14 =1 atom 100-00 Obviously 1 atom oxide of lead, and h an atom of sugar. Sugar forms with oxide of lead two compounds, one soluble,' and the other insoluble. If we digest oxide of lead i;i a certain quantity of sugar, we obtain a yellowish solution, which reacts as an alkali, and leaves, when evaporated, an incrystallizable mass. It is probable that this soluble compound, which has not been analyze'!, is a com- pound of 2 atoms sugar and I atom oxide of lead. 15. M. Desfo&ses assures us, that solutions of pure sugar in water, whether concentrated or dilute, may Iso kept any length of time without alteration. But when sugar is dissolved in water which has been boiled over washed yeast, or gluten of wheat, it un- dergoes a remarkable change. Gas is evolved, consisting of a mixture of carbonic acid and hydrogen gases, and a part of the sugar is converted into a substance having the properties of gum ; but which, when digested with nitric acid, does not form mucic acid, but only oxalic acid.J 16. Sugar possesses the remarkable property of dissolving the carbonate and diacetate of copper, and of forming a green-coloured liquid, from which the oxide of copper is not precipitated by the alkalies, though it is by the prussiato of potash, and by sulphu- retted hydrogen. When sugar is boiled with salts of copper, it reduces the copper to the metallic state. When sulphate of copper is employed, metallic copper is precipitated, and a small quantity of a cupreous salt remains in solution. Along with the metal a brown substance falls, which is soluble in ammonia. Nitrate of copper, subjected to the same treatment, ^ives no precipitate; but the copper is transformed into red oxiue, and caustic potash throws down a yellow hydrate of red oxide. When sugar is boiled with acetate of copper, a great deal of red oxide precipitates, acetic acid is disengaged, and the solution, when evaporated, gives an incrys- tallizable magma. § Solution of sugar produces no sensible alteration when poured into a solution of nitrate of silver. But when the mixt re is boiled, * Nicholson's Journal, xviii. 9. t Annals of Pliilosophy, v. 2(i3. I Jour, lie Pliarmacic, xv. 602. § Voge), Schweiggtr's Jouniiil, xiii. 102. mce dis- ,he oxide ; a light ompomid insoluble id for our luble/and [1 quantity an alkali, 3 probable ss a com- sugar in length of in water eat, it un- sting of a >art of the js of gum ; nucic acid, ivolving the !n-coloured ited by the by sulphu- copper, it e of copper quantity of tal a brown of copper, e; but the ash throws boiled with acetic acid 3 an incrys- lien poured re is boiled. , XV. 602. COMMON SUGAH. 631 a brownish-black powder falls, which, according to Vogel, is a mix- ture of metallic silver and oxide of silver.* When solutions of sugar and corrosive sublimate are mixed, calomel is precipitated. Chloride of gold gives with sugar a precipi- tate, at first light-red, but gradually becoming dark coloured.! When sugar is mixed with a solution of peroxide of iron, the whole of the peroxide cannot be precipitated by ammonia, as H. Rose first observed. Malagutti has shown, that potash acts upon sugar precisely as acids do, converting it first into sugar of grapes, then into ulmic acid ; and if atmospheric air be present, into ulmic and formic acid.J Hi. Sugar is soluble in alcohol, but not in so larjje a proportion as in water. According to Wenzel, 4 parts of boiling alcohol dis- solve 1 of sugar.§ But this proportion is surely too great. Lewis could only dissolve 1 part of sugar in 1 2 of boiling rectified spirits, and MargrafFin IG parts. When the solution is set aside for a few days, the sugar separates in elegant crystals. || Sugar unites readily with oils, and renders them miscible with water. A moderate quantity of it 'prevents, or at least retards, the coagulation of milk ; but Schecle discovered that a very large quantity of sugar causes milk to coagulate.^f 17. The hydrosulphurets, sulphurets, and phosphurets of alkalies and alkaline earths, seem to have the property of decomposing sugar, and bringing it to a state not very ditterent from that of gum. Mr Cruickshanks introduced a quantity of syrup into a jar standing over mercury, and then added about an equal quantity of phosphuret of lime. Phof'phurctted hydrogen gas was immediately extricated. In eight days the syrup was withdrawn : it had lost its sweet taste, and acquired a bitter and astringent one.** From this solution alcohol threw down white flakes, very much resembling those of mucilage separated from water by the same liquid.tt A little sugar was dis- solved in alcohol, and phosphuret of lime added to it. No apparent action took place. The mixture, after standing in the open air for some days, was evaporated, and water added. No gas was disen- gaged, as the phosphuret had been converted into a phosphate. The liquid being filtered and evaporated, a tenacious substance remained, much resembling gum arable. Its taste was bitter, with a slight degree of sweetness. It did not seem soluble in alcohol. It burned like gum.|t Similar experiments were made by this ingenious chemist with the sulphurets. Tlic sweet taste of the sugar was destroyed ; but on account of the solubility of the different products, the nature of the change could not be ascertained, * Vogel, Schweiggcr's Journal, xiii. 174. f Ibid. xiii. 174. X Jour, de Pharmacie, xxi. 464. § Verwandf chaf't, p. 305. Il Lewis, Neumann's Chemistry, p. 329. Margrati, Opusc. i. 217. f Scheele, ii. 32. Dijon Trans. ** This is the taste of i)hosnhuret of lime. ff Rollo on Diabetes, p. 4j2. %X ^^--'luicksnaaks, RoUo on Diabetes, p. 432. ILni ii '1. '■\ '• \ ! ' ' 1 ■i ^1 1 632 SUGARS. 18. When heat is applied to sugar it melts, swells, becomes brownish-black, emits air bubbles, and exhales a peculiar smell, known in French by the name of caromel. At a red heat it instantly bursts into flames with a kind of explosion. The colour of the flame is white with blue edfres. When sugar is distilled in a retort, there comes over a fluid which, at first, scarcely difliers from pure water ; by and by it is mixed with pyromucic acid ;* afterwards some empyreumatic oil makes its appearance, and a bulky charcoal remains in the retort. This charcoal very frequently contains lime, because lime is used in refining sugar; but if the sugar, before being submitted to dis- tillation, be dissolved in water, and made to crystallize by evapora- tion in a temperature scarcely higher than that of the atmosphere, no lime whatever, nor any thing else, except pure charcoal, will be found in the retort. During the distillation, there comes over a considerable quantity of carbonic acid and carburetted hydrogen gas.f Sugar, therefore, is decomposed by the action of heat; and the following compounds are formed from it : — Water, pyro- mucic acid, oil, charcoal, carbonic acid, carburetted hydrogen gas. The quantity of oil in a separate state is inconsiderable ; by far the most abundant product is pyromucic acid. Sugar, indeed, is very' readily converted into pyromucic acid ; for it makes its appearance always whenever syrup is raised to the boiling temperature. We are indebted to Mr Cruickshanks for the most precise set of experiments on the decomposition of sugar by heat. 480 grains of pure sugar were introduced into a coated retort, and heated gradually to redness. The products were. Grains. Pyromucic acid, with a drop or two of oil 270 Charcoal . . . . . 120 Carburetted hydrogen, and carbonic acid gas 90 480 The pyromucic acid required about 75 grains of a solution of potash to saturate it ; and when thus neutralized, no ammonia was disengaged. Hence sugar contains no azote, unless we suppose a very minute portion to be present in the pyromucic acid; which is not the case. The charcoal burns away without leaving any residue. Hence sugar contains no earth nor fixed alkali. The proportion of the gaseous products was 119 ounce measures of carburetted hydrogen, and 41 ounce measures of carbonic acid gas.l These experiments are sufficient to show us, that sugar is com- * Schrickel, in his Dissertation Do Salibus Saccliarinis, published in 177G, en- (IcHVoured to show that pyroniiicous acid was a mixture of vinegar, oxalic, and tartaric acids, Fourcroy and Vunqueiin suf^gcsted more hitely tiiat it is merely acetic acid united to a little oil. It is now known to be a peculiar acid. t Scopoli and Morveau, Encyc. Meth, Chim. i. 209. X Rollo on Diabetes, p. 452. I COMMON SUOAH. 633 becomes ir smell, instantly the flame id which, ixed with nakes its •t. This 5 used in •d to dis- r cvapora- mosphere, rcoal, will omes over hydrogen of heat; ater, pyro- irogen gas. by far the sed, is very' appearance ire. •ecise set of m grains of id gradually iO 30 I sugar is com- .ed in 1776, en- c|,'ai, oxalic, anJ liul it is merely ar acid. 69. posed entirely of oxygen, carbon, and hydrogen. It is, of course, a vegetable oxide. Lavoisier endeavoured to determine its consti- tuents experimentally ; but at that time pneumatic chemistry had made too little progress to permit him to approacli very near the truth. The first chemists who attempted a rigid analysis of sugar, were Gay-Lussac and Thenard. They burnt determinate quantities cf crystallized sugar with chlorate of potash, and ascertained the quantity of carbonic acid and water which it yielded, from which they deduced the constituents. Ber/elius and Brimner also ana- lyzed sugar. The following table shows the results obtained : — Gay-Liisaac and Thcnartl. ncrzcUus. Brunner. Carbon Hydrogen Oxygen 42-47 6-90 50-63 42-225 6-600 51-175 42-244 6-415 51-341 lOO-OO'' Pure sugar candy Impure sugar candy East India sugar candy English refined sugar Carbon, 42-85 41-5 41-9 41-5 to 5T-5 to 57-5 loot I 100$ I , In 1827, Dr Prout published a very careful and accurate set of experiments on the ultimate composition of simple alimentary sub- stances. Among others, he analyzed all the difi'erent varieties of common sugar that occur in commerce. § The following table exhibits the results which he obtained : — Water.- + 57-15 to 42-5 + 58-5 + 58-1 to 42-5 + 58-5 East India refinedsugar 42-2 + 57-8 Maple sugar . . 42-1 Beet sugar . . 42-1 Of course the first, or pure sugar candy, exhibits the constitution of pure sugar. The oxygen and hydrogen in sugar, Dr Prout considers, with Gay-Lussac and Thenard, as existing in the pro- portion which constitutes water. Hence the constituents of pure sugar candy are, according to his analysis. Carbon .... 42-85 Hydrogen . . . . 6-35 Oxygen .... 50-80 + 57-9 + 57-9 100-00 M. Liebig, in 1834, repeated these analyses with the most scrupulous attention to accuracy. He obtained, from 100 parts of crystallized sugar, * Rccherches Physico-Chimiques, ii. 288. t Annals of Pliilosopliy, v. •2G2, and Traito de Ciiimic, v. 242. j: Annaleu dor Pliarinacic, xiv. 319. §?\\\l Trans, 18-27, p. 355. k ; ' \\' >^\ (6 '\f^ H , : '. i >l 634 8(l(;ARit. 1 1 Carbon . Ilydi jjen Oxygun 41-70 6-45 Now, if wn consider sugar in crystals fis n couiinmnd of 12 atoms carbon = U'OO or per cont. 42* II 1 1 atoms hydrogen = 1*375 — — ()*43 1 1 atoms oxygen =11*00 — — 51*46 21*375 100*00 the proportions of the constituents corresiM)nd with the; analysis. Horzelius has shown that crystallized sugar contains an atom of water. C'onsecjuently anhydrous sugar nuist be a conij)OJiiid of 12 atoms carbon = !) or per cent. 44*44 10 atoms hydrogen = 1*25 — — 6*18 10 atoms oxygen =10 _ _ 4!»*38 20*25 10000 Anhydrous sugar of consequence is resolvable into 2 atoms ether . . C* II'" 0« 4 atoms carbonic acid . C'* ()" Qii H'" O'" The eth'T-, !•} uniting with 2 atoms of water, is converted into 2 atoms (.i ^!; ulx 1. Thus it appears that cane-sugar, during itsfer- U'cntion ai)Sorl'3 water, and is resolved into Alcohol 51*12 Carbonic acid . . . 48-88 100*00 An important observation was lately made by MM. Gregory and Demar(;ay. If, into a very dilute acjueous solution of sugar, we pour permanganate of potash, we obtain a neutral solution of oxalate of potash. Were we to admit sugar to consist of C* H'° O'", then 6 atoms of permanganate of potash composed of Mn" O^^, would convert 1 atom of sugar into 6 atoms of oxalic acid, composed of C'^ O'** -j- 6 (K O). The H'" O'" of the sugar, of course, become water, whilu the Mn** O^^ are equivalent to G atoms of manganesious acid.f We are indebted to M. Edmund Fremy for an important set of experiments on the distillation of sugar, mixed with anhydrous lime.| The best proportions are, 1 part of sugar and 8 parts of lime. The lime must be in fine powder, and the sugar must be intimately • Annaleu der Pliartnacic, ix. 21. f Ann. ile Chiin. ct tie Piiys, Ixiii. 139. X Annalun dcr Phaniiacic, xv. "277. COMMON HU(iAll. 035 luixud with it, no tliul tho luiimtcst purtiole of it nmy bu Htirroundcd with lime. The caniicity of the vessel in which ilie process in eon- ihjctcd, oujrht to bo twice that of tho powder (ontained In it, liccause the lui'iture swells up considerably during the diatillution. The heat must bo upj)lied j«lowly. After a certain time wati r is disouijnf^ed froni the su^^ar, wliich, by its combinution with tho lime, occnsio'is the evolution of so much heat that tho lire may b(^ with- drawn. The reaction continues for some time strong, and then suddenly terminates of itself. Scarcely any gas is evolved. Hut an oily matter passes over, having an etlui' ' snioll, and a light- amber colour. When this oily-looking matter is agitat of it dissolves, while another portion rem. is tlie watt y solution is heated to between ''^ licpiid passes over, havhig a burning taste huu an agreeable smell. It is completely soluble in water, and boils at 140". It was re- peatedly analyzed, and found composed of Carbon ()1'82 or 3 atoms = '2'25 or per cent. ()2'07 Hydrogen 10-67 or 3 atoms = 0-375 — — 10-34 Oxygen 27-51 or 1 atom =1 — — 27*59 "•'ter, one portion .1' i upon. When ! 76°, a volatile 100-00 3-625 100-00 It is evident, from this analysis, and from the properties above described, that this liquid is acetone. The oil, which is insoluble in water, is purified by rectifications, though it is peculiarly difficult to free it from all traces of acetone. It is colourless, has an agreeable smell, is soluble in alcohol and ether, but insoluble in water. It boils at 183°. It was analyzed by M. Fremy, who obtained Carbon 7234 or 6 atoms = 4-5 or per cent. 73-47 Hydrogen 10-17 or 5 atoms = 0-625 — 10-20 Oxygen 17-49 or 1 atom =1 — — 16-33 100-00 6-125 100-00 If we double the atoms of the acetone, it will be evident that this oily matter differs from it by the absence of an atom of water. For Acetone . . . C« 11'' O" The oil . . . . C« H'* O Difference ... HO Fremy, on this account, has given it the name of metacetone. 2 atoms of sugar . . C W O" sugar may be resolved into 3 atoms of metacetone 6 atoms carbonic acid 7 atoms water C'8 H'5 03 H7 O^ QH H22 Q22 l'. n ^. A^< IMAGE EVALUATION TEST TARGET (MT-3) // ^«^% ' -* V^^ <" 1.0 I.I ■^ 1^ 12.2 L25 i 1.4 III 1.6 P; "% -^ '4 %j^ Photographic Sciences Corporation «v^ '> ^-^ 23 WEST MAIN STREET WEBSTER, N.Y. 14StO (716) 872-4503 ''h ^ 4^ K, 686 SUOARS. u Thus we see that 2 atoms of sugar may be resolved into 3 atoms ^metacetone, 6 atoms carbonic acid, and 7 atoms water. And 1 atom of sugar may be resolved into b atoms of acetone, 3 atoms of car- bonic acid, and 2 atoms water. For 1 atom sugar is C H'* O*'. 3 atoms acetone is . C H' O' 3 atoms carbonic acid . C* O^ 2 atoms water . . H' O' C»2 H" 0>' When starch and gum are substituted for sugar, and distilled with lime, the same products are obtained. The starch seems to furnish more metacetone than acetone, while the gum gives more acetone than metacetone. SECTION II. — OF LIQUID SUGAR. Liquid sugar was first pointed out by Proust. He has shown that it exists in a variety of fruits and vegetable juices. It is dis- tinguished from every other species of sugar, by being incapable of crystallizing. It can only be exhibited in a liquid state. It is transparent and colourless when pure, and is more soluble in alcohol than common sugar. By means of that liquid it may be separated from common sugar, when they happen to be mixed. It exists in the sugar-cane juice, and constitutes, according to Proust, a con- siderable portion of the molasses. It exists also in grapes, peaches, apples, and other fruits.* From the experiments of Auarie it ap- pears, that a liquid sugar may also be obtained from the stalks of the Zea Mays, or Indian corn ; but no method tried was capable of inducing it to crystallize.f From the experiments of Vogel and Bouillon Lagrange, there is reason to suspect that liquid sugar may be merely common sugar deprived of the power of crystallizing, by being combined with an acid. SECTION 111. — OF SUGAR OF GRAPES AND STARCH. That grapes contain abundance of sugar has been long known. The Due de Bullion first extracted it from the juice of grapes, and Proust pointed out the difference between it and common sugar. The juice of grapes, according to him, yielded from 30 to 40 per cent, of this sugar.J The sugar of grapes is not so white as com- mon sugar, but it crystallizes much more readily.§ Proust has published a long dissertation on the properties of this sugar, and the method of extracting it from grapes. It was of great importance on the continent during the last war, on account of the difficulty of obtaining sugar from the West Indies. Verjuice, or the liquid obtained from unripe grapes, contains tartar, sulphate of potash, sulphate of lime, much citric acid, a little malic acid, extractive, and water ; but neither gum nor sugar. As * Proust, Ann. de Chim. Ivii. 131. % Jour, lie Phys. xxix. 5, and Ivi. 113. f Ann. de Chim. Ix. 61. § Nicholson's Jour. xiv. 178. SUGAR OF GRAPES AND STARCH. atoms 1 atom of car- 637 the grapes advance to maturity, the citric acid gradually disappears, and gum and sugar appear in its place. The juice of ripe grapes contains also gluten and fibrous matter, merely in a state of mixture, and therefore separable by the filter, or still better by boiling and skimming the liquid. The substances held in solution are chiefly sugar, syrup, gluten, gum, and extractive. When this juice is evaporated to dryness, it yields from a third to a fifth of solid matter, according to the species of grape employed, and the season of the year. To extract the sugar from this juice, Proust saturated the acids which it contains with potash, boiled it down to a half, and left it at rest. By this means several of the salts subsided. Its specific gravity was 1'215. It was then mixed with blood, heated, skimmed, filtered, and boiled down to a syrup. It gradually becomes crys- tallized, and resembles the raw sugar from the West Indies. In this state its specific gravity is about 1*500. cording to Proust, is composed of Crystallizable sugar Syrup, or uncrystallizable sugar Gum ..... Malate of lime This raw sugar, ac- 75-00 24-44 0-31 0-25 100-00 Besides some extractive, the quantity of which cannot well be as- certained. The syrup holds in solution a considerable quantity, probably more than half its weight, of crystallizable sugar ; but it is difficult to separate it. The raw sugar thus obtained is not so sweet as that from the sugar cane, since four parts of the latter will go as far as five parts of the former. But it may be applied to all the purposes of com- mon raw sugar. This raw sugar may be refined precisely in the same way as that of the sugar-cane. It is then white, but inferior in consistence to common sugar. It is not so sweet, and has a striking resemblance to the sugar of honey. It does not crystallize, but assumes the form of sphericles. It is not so soluble as the sugar of canes, and is therefore more easily separated from tho other substances in the juice of grapes. Proust informs us that the raw sugar from grapes, when diluted sufficiently with water, ferments and is converted into wine. Starch may be converted into a sugar possessing exactly the properties of sugar of grapes, by mixing it with about 4 times its weight of water, and about xau*^^ P^rt of its weight of sulphuric acid, boiling the mixture for thirty-six hours, supplying water as fast as it evaporates ; then saturating the acid with lime, separating the sulphate of lime, and concentrating the liquid by sufficient eva- poration. This curious fact was accidentally discovered by KirchofF, a Russian chemist, as he was employed in a set of experiments to 638 SUGARS. \ 1 convert starch into gum. He conceived that the starch could be rendered soluble in water by boiling it with very dilute sulphuric acid ; and by prolonging the boiling, he gradually observed the con- version of the starch into sugar. Vogel ascertained that during the conversion of starch to sugar, no gas whatever is extricated. Mr Moore* and M. de Saussuref ascertained, that the quantity of sul- phuric acid was not diminished by the process. Saussure ascer- tained that 100 parts of starch, when converted into sugar, become 110*14 parts. Hence he drew as a conclusion, that starch sugar is merely a compound of starch and water in the solid state.f Ac- cording to his analysis, the constituents of starch sugar are as follows: — Oxygen 55*87 Carbon 37'29 Hydrogen .... 6*84 100*00 Dr Prout has subjected the sugar of starch to an analysis, by means of oxide of copper, and found it composed of Carbon 36*20 or 12 atoms =9 or per cent. 36*36 Hydrogen 7*09 or 14 atoms = 1*75 — — 7'07 Oxygen 56*71 or 14 atoms z= 14 — — 56*57 Or, 100*00§ supposing it anhydrous, 12 atoms carbon 24*75 9 or per cent 100*00 .40 12 atoms hydrogen ^ 1*5 — — 6*66 12 atoms oxygen ™— 12 — '— 53*33 22*5 100 It differs from common sugar, by containing two additional atoms of water. Hence it is resolvable inv :ohol and carbonic acid, without absorbing any water from the i in which the fermenta- tion takes place. Braconnot has shown that by a similar process, saw-dust, straw, linen rags, and even the bark of trees, may be converted into a sugar similar to that of gravies or starch. || Starch sugar has the remarkable property of combining with common salt, and forming a compound which crystallizes in pyra- midal dodecahedrons and rhomboids, which contain 6 or 7 per cent, of water of crystallization. These crystals dissolve readily in water and absolute alcohol. According to Brunner, they are composed (supposing them anhydrous) of Sugar ' . . . . 75 or 22*5 Common salt . . . 25 or 7*5 100 * Phil. Ma?, xl. 134. f Annals of Philosophy, vi. 424. % Ibid, vi 426. § Phil. Trans. 1827, p. 373. || Ann. de Chim. et de Phys. xii. 181. MUSHROOM SUGAR. 639 We see from this, that it consists of an atom of each consti- tuent. Honey f which bees collect from flowers, is a concentrated solution of grape sugar. It is well known that honey, as it is deposited in the cells of the combs by the bees, is a semifluid transparent liquid, having a yellow colour, and a peculiar sweet taste. When this honey is left at rest it gradually separates into two portions. The one remains in a liquid state, the other becomes solid, and assumes the form of small whitish-coloured sphftricles. The liquid portion, so far as is known, exactly resembles the liquid sugar from the sugar-cane ; while the granulated portion is identical with the sugar of grapes. The liquid sugar is easily separated from the crystal- lized portion, by washing the crystals in alcohol, which dissolves the liquid sugar much more easily than the solid. The crystals are needles diverging from a centre, and constituting little spheres. The constituents of these crystals of sugar of honey, according to the analysis of Prout, are Carbon 36*36 Hydrogen . . . 7*07 Oxygen 56*57 100*00* obviously consisting of the same number of atoms as starch sugar. SECTION IV. — OF MUSHROOM SUGAR. M. Braconnot obtained from the juice of the ngaricus volvaceus, by evaporation, a species of sugar, which difi^ers from common sugar. It crystallizes in four-sided prisms with square bases. It has such a disposition to crystallize, that when a very weak aqueous solution of it is put upon the surface of a vessel, it is im- mediately sprinkled with small acicular crystals. When heated this sugar melts, swells, and takes fire, giving out the odour of caro- mel. There remains a small quantity of charcoal, which is desti- tute of alkali. Acids do not deprive this substance of the power of crystallizing as they do common sugar. When digested with nitric acid it produces abundance of oxalic acid ; but no bitter principle. It is capable of undergoing the vinous fermentation.! This sugar is colourless. It is much less sweet than common sugar, and is not so soluble either in water or alcohol. Besides agaricus volvaceus, it has been found in agaricus acriSf theogalus^ campestris ; in boletus juglandis ; peziza nigra ; meruliuf cantharellus; phallus impudicus; hydnum hyhridum, and repan- dum. A quantity of this sugar, extracted by M. Blanchet from the cantharellus esculentus, and the clavellaria coralloides, was analyzed by Liebig and Pelouze. It did not ferment with yeast, and was composed of 1 .?: • Phil. Trans. 1827, p. 373. f Ann, do Chim. Ixxix. 278. 640 SUGARS. 'I Carbon . Hydrogen Oxygen . 39-06 7-71 53-23 100-00* Now it will be seen, in the next Section, that this is the composition of mannite. Mushroom sugar, then, is nothing else than mannite. SECTION V. — OF MANNA. Manna was long considered as a substance which fell from the heavens, till incontestable experiments demonstrated it to be an exudation from trees. It has the form of oblong globules or masses, of a yellowish-white colour, and some degree of transparency. It is the produce of various trees, but is chiefly procured from the fraxinus ornus, a species of ash, which grows abundantly in Sicily and Calabria. It partly exudes spontaneously during the summer months, and is partly obtained by incisions. The juice gradually concretes into a solid mass, or it is dried in the sun or in stoves.f The fraxinus rotundifolia also yields manna, as well as the ornus. It exudes likewise from the pinua larix. This exudation is known by the name of manna of Brian9on. It is so much mixed with tur- pentine, that it is very little used. Vogel has shown also that it exists in the leaves of the apium graveolens, or celery. X And Four- croy and Vauquelin extracted a substance resembling manna, in considerable quantity, from onions.§ The manna of the shops is obtained from the ornus. But there is a tree in New South Wales, the eucalyptus mannifera, which, according to Dr Mudie, yields a manna exactly similar to that of the ornus. It is now imported from Botany Bay for medical pur- poses. || To obtain pure manna it is only necessary to dissolve the manna of the shops in boiling alcohol, and allow the solution to cool. The manna crystallizes. The crystals are white, and have the form of four-sided needles. Its taste is sweet and agreeable, and when placed upon the tongue, it dissolves rapidly, producing a sensation of cold. It is very solu- ble in water, and iPorms a syrup which crystallizes readily, when sufficiently concentrated. It dissolves very readily and abundantly in alcohol, and crystallizes on cooling. When digested in nitric acid it yields both oxalic and saclactic acids, whereas sugar only yields oxalic acid.^ It does not ferment like sugar, and of course * Ann. de Chim. et de Phys. Ixiii. 140. f See Neumann's Che nistry, p. 325, from which all the accounts of manna to be found in chemical books have been copied. 1 Schweigger's Jahrbuch, vii. 363. § Ann. de Chim.'lxv. 161. II Jour, de Pharmacie, xviii. 705. We learn from Mr Wcllsted, that the Be- douin Arabs collect yearly above 700 lbs. of manna in the neighbourhood of Mount Sinai. The manna of that country is supposed to be an exudation from the Hedysarum Alhagi ; that of the wilderness is said by Elirenberg to come from a species of Tamarix. Whether it be similar to the manna of Moses, can- not be ascertained. See Ann. der Pharmacie, xxv. 80. If Proust, Ann. de Chim. Ivii. 144. MANNA. 641 m Z to come does not seem capable of furnishing alcohol.* In a set of experi- ments on the juice of the common onion {allium coepe)^ Fourcroy and Vauquelin found that, at a temperature between 66° and 80°, it gradually underwent the acetous fermentation, without emitting any gas ; and that by this process a quantity of uncrystallizable 8u> gar, which it contained, assumed most of the properties of manna. It was not precisely the same, however, with manna, for it did not yield saclactic acid when treated with nitric acid. The common manna of the shops, according to the experiments of Fourcroy and Vauquelin, consists of four different ingredients. 1. Pure manna, which constitutes at least fths of the whole. 2. A little common sugar, which makes it fermentable to a small extent. 3. A yellow matter with a nauseous odour, to which the purgative quality of manna seems owing. 4. A little mucilage converted into saclactic acid. This last ingredient seems hypothetical. Several substances, by fermenting, seem to be converted into manna. The sugar in onion juice has been already mentioned. Fourcroy and Vauquelin found likewise that fermented melon juice contained manna, though none could be detected in it before the fermentation. Manna appears sometimes to be formed and deposited by insects.! Manna has been analyzed both by M. de Saussure, Dr Prout, M. Oppermann, Henry and Plisson, and Rrunner. The follow- ing table exhibits the results of these analyses: — SauHure.t Prout. ^ Oppcrmann.|| Henry and PliMOl,.! Brunncr.** ! 38-53 7-87 53-60 38-7 6-8 54-5 39-98 7-80 52-22 38-77 8-48 52-85 40-084 7-529 52-387 100-00 100-0 100-00 100-10 100 Carbon Hydrogen . Oxygen If we calculate from Dr Prout's analysis, we find that mannite is a compound of 9^ atoms carbon = 7-125 or per cent. 38-77 10 atoms hydrogen = 1-25 — — 6-80 , 10 atoms oxygen = 10-00 — — 54 -43 ■^- 18-375 100-00 But Liebig and Pelouze consider mannite as composed of 1 2 atoms carbon = 9-0 or per cent. 39-56 14 atoms hydrogen = 1-750 — — 7-69 12 atoms oxygen =12-0 — — 52-75 22-750 100-00 Numbers which approach very nearly to the results obtained by Oppermann. * Du Puytren and Thenard, Ann. dc Chim.lix. 51- t See Klaproth, Gehlen's Jour. iv. 328. % Annals of Phil. vi. 424. § Phil. Trans. 1827, p. 384. || PoggendorFs Annalen, xxiii. 445. If Jour, de Pharmarie, tx. 63. *• Ann. der Pharm. xiv. 320. 2t 642 SUGARS. W' M. Mitousrt fonnd a sugar in the root of the pomegranate tree, which he called grenadin. Boutron-Charlard and Guillcmet have shown it to be identical with mannite.* About the year 1815, specimens of a sweet substance were brought from Botany Bay. They were snow-white, in the form of tears, and had obviously dropped in a liquid state from some vegetable. I was informed that these tears were collected in a plain covered with wood ; but of what species I could not learn. Some bushels of it might have been collected. These tears had a sweet and agreeable taste. They dissolved in much greater quantity in alcohol than common sugar, and when the alcohol cooled it deposited the sugar abundantly in needle-form crystals. The form of these crystals ap- proached that of manna ; but was not quite the same. Nor did it make so cooling an impression on the tongue. It was therefore a peculiar species of sugar ; though approaching much nearer to manna than any of the preceding species. It is very much to be wished that more complete information could be obtained respecting this species of sugar, and that sufficient quantities of it could oe sent over to this country, to permit an accurate set of experiments on it to be made. SECTION VI. — OF LIQUORICE SUGAR. Liquorice sugar is the Inspissated juice of the glycyrrhiza glabra, a plant which is a native of Spain, and other countries situated in the south of Europe. It is cultivated in England, chiefly, it is said, in the neighbourhood of Pontefract ; and Pomet commends the English liquorice root as the best of any. The use of this root in medicine, and the method of obtaining its inspissated juice in a solid form whei it is denominated liquorice, or black sugar, seems to have been known to the ancients. For Pliny gives a description of the glycyrrhiza^ which applies very well to our plant, and mentions the method of obtaining the inspissated juice, and its use in medicine.f What is called black sugar, or liquorice sugar, in this country, is merely the inspissated decoction of the roots of the glycyrrhiza. It is manufactured in Spain, and it is said also in Germany and Hol- land. It comes to this country wrapt up in bay leaves. The Ger- man and Dutch liquorice is said to be adulterated with the rob of plumbs. Pure liquorice sugar is best obtained from the decoction of the root, or from black sugar. Dissolve the black sugar in water, clarify the solution with the white of eg^, without which it cannot be fil- tered. Filter and then pour sulphuric acid into the solution, which occasions a precipitate of the sugar, united to a certain quantity of vegetable albumen. Collect this precipitate on a filter, and wash it till the water ceases to become coloured. Then dissolve it in alco- hol, which, leaving the albumen, dissolves only the sugar combined Ann. der Pharm. liv. 82]. f Plinii Hist. Nat. lib. zxii. cap. 9. LIQUOniCE SUGAR. C43 with the acid. Lot fall into the solution, drop by drop, a solution of carbonate of potash, till the liquid ceases to be sensibly acid. Filter and evaporate. The sugar remains under the form of a yel- low, translucid mass, cracked m all directions, and easily detached from the vessel in which it was evaporated. Its taste is similar to that of liquorice root. It is soluble both in water and alcohol. When heated it swells up like borax, takes fire, and bums with a lively flame and much smoke. When thrown in the state of a powder into the flame of a candle, it burns like lyco- podium, but with a whiter colour. It has a great affinity for acids, salifiable bases, and salts. With acids it forms compounds little soluble in water, and almost insoluble in water acidulated with an acid. Some time elapses be- fore these compounds precipitate from a dilute solution. The vegetable acids form these combhiations, as well as the mineral acids. Sulphated liquorice sugar is deposited at first like a light cloud, and gradually collects into a coherent mass, which becomes slowly viscid, like a half-fused resin, when kneaded in warm water. Its taste, after being well washed, is sweet, like that of liquorice sugar ; but the compound collects on the tongue, and dissolves very slowly in the saliva. Boiling water dissolves it, and when the sa- turated solution is allowed to cool, it assumes the form of a tremu- lous jelly. The colour of the solution is light-yellow. It is soluble in alcohol, and the compound is not thrown down when the solution is poured into water. When the alcoholic solution is evaporated, there remains a translucent, light-yellow substance, which, when dry, is transparent and straw-yellow. It burns like liquorice sugar, and leaves no trace of ashes. The acetate of liquorice sugar is obtained in the same way as the sulphate, which it resembles in its properties, excepting that it is much more soluble in boiling water, and forms a firmer jelly. When dry it has the form of white crusts, having a sweet taste. Liquorice sugar combines also with bases. Hence it happens, that when we precipitate it by an acid, and then saturate the acid with a base, the sugar combines with the excess of that base. Hence in such cases we must beware of adding any ext -, of base. It is better to leave a very little of the acid unsaturated with the base. If we mix the carbonates of potash, barytes, or lime, with liquorice sugar, and digest the mixture, the carbonic acid is disengaged by Kttle and little, and the sugar combines with the base. When the combination (which is soluble) does not contain an excess of alkali, its taste is purely sweet. When treated with an acid, not the smallest trace of carbonic acid is given out. These combinations dissolve readily in water ; but are not so soluble in alcohol. They do not crystallize, and when dry resemble extracts. They are not decora- posed by carbonic acid. When we add carbonate of barytes or of lime to an alcoholic solution of sulphated liquorice sugar, and digest the mixture a long time, we obtain a portion of the compound in a state of solution ; but in proportion as the digestion is prolonged, a 644 8DOAR8. ' i larger proportion precipitates, which is soluble in water. This is the compound of the sugar with the base, free from carbonic acid. Liquorice sugar combines also with sails ; though the pure sugar^ recently extracted from the roots of the plant, docs not combine so readily as common black sugar docs. When we separate this last by means of carbonate of potash, from its sulphate dissolved in alco- hol, we obtain a brown precipitate, completely soluble in water, which gives when evaporated a black mass, cracked in every direc- tion, but not crystallized, and having a sweet taste. Liquorice sugar precipitates the greater number of metallic solu- tions. For example, solutions of nitrate of copper, acetate of lead, sulphated peroxide of iron, protochloride of tin. But corrosive sublimate is not precipitated. These precipitates are combinations of the sugar with the salt, and when decomposed by sulphuretted hydrogen, they give no (or very little) matter soluble in cold water. But some, as for example, the precipitate with protochloride of tin, are (' omposed by alcohol. Alcohol dissolves from this precipitate a mix* e or sugar and muriate of sugar, and leaves a residue contain- ing protoxide of tin. Tf we drop a solution of sugar into trisacetate of lead, we obtain a precipitate composed of sugar and oxide of lead. Sulphuretted hydrogen decomposes this precipitate. But the sugar retains sul- phuret of lead, and cannot be purified by filtration.* Berzelius informs us, that liquorice sugar may be extracted from the leaves of the abrus precatorius.^ This is the tree which yields the red peas, black at one extremity, used for necklaces. The sugar extracted from the polypodium vuigare, has considerable resemblance to liquorice sugar. But Berzelius has shown that its chemical cha- racters are quite different.^ The root of glycyrrhiza glabra was subjected to analysis, by M. Robiquet, who obtained the following substances from it : — n.) Starch, first observed in it by M. Lautour. (2.) Gluten, which is separated by boiling. (3.) Liquorice sugar. (4.) Phosphates and malates of lime, and magnesia. (5.) A brown thick resinous oil, which gives an acrid character to the decoction of liquorice. (6.) A substance similar in its properties to asparugin; but crystallizing in octahedrons. (7.) Woody fibre. § It appears from the experiments of M. Zier, that the root of this plant contains copper ; .nd that this metal is to be found also in the decoction. II SECTION VII. — OF SUGAR OF FIGS. The sugar of figs may be seen in a concrete state upon the out- * Berzelius, Ann. de Chim. et de Phys. xxxvii. 186. t Trait6 de Chimio, v. 260. ' % Ibid. p. 262. $ Ann. de Chim. Ixx. 185. || Jour, de Pharmacie, xix. 226. , This !■ [)ntc acid. )urc sugar, combine so :e this last ed in alco- in water, very direc- itallic solu- ite of lead, t corrosive mbinations ilphuretted cold water, ride of tin, recipitate a ue contain- , wc obtain nlphurctted retains sul- •acted from rhich yields The sugar esemblance 2mical cha- jrsis, by M. I character ragin; but oot of this also in the m the out- .262. ,226. ULYCERIN. 64& side of that fruit in the statu in which it is usually sold in the shops in this country. If wo dissolve it in boiling alcohol and set the liquid aside, wo may easily obtain it in the state of crystals. These crystals have a form diilurent from that uf common sugar ; ndr do they appear to my taste quite so sweet. Hence they must consti- tute a distinct species. SECTION VIII. — OF SAnCOCOLLIN. Sarcocoila usually conies to this country from Persia, Turkey, and India. It is commonly in the state of oblong globules, from the size of a pea to a grain of sand. Its colour is yellow and it has the translucency and much of the appearance of gum arable. It exudes from all the parts (especially the calyces) of tiie penaa mucronata, a shrub which is a native of Persia and Arabia. This substmice con- sists principally of a peculiar principle, to which Pelleticr has given the name of sarcocollin* To obtain it wc have only to digest sarcocoila in ether, to dissolve a resinous matter which is present. Absolute alcohol will now take up the sarcocollin, which it lets fall when evaporated. The colour, as I have obtained it, is brownish-white. Its taste is sweetish, leaving at the same time an impression of bitterness, and in the mouth it dissolves like gum. It cannot be made to crystal- lize. It is soluble in water, and the solubility is augmented by heat. It is soluble also in alcohol ; but insoluble in ether. When digested in nitric acid it is converted into oxalic acid. Thetincture of nut-galls, when poured into a solution of sarcocollin, occasions a copious light-yellow precipitate. The infusion of nut- galls only throws down a slight precipitate, and gallic acid nothing at all. It is precipitated also by diacetate of lead; but not by nitrate or acetate of lead, corrosive sublimate, nitrate of silver, sulphate of zinc, or sulphate of copper. Concentrated sulphuric acid dissolves it, but deepens its colour. The constituents of sarcocollin, as determined by Pelletier, are Carbon 57" 15 or 22 atoms = 16*5 or per cent. 57' 14 Hydrogen 8-34 or 1 9 atoms = 2-375 — — 8-22 Oxygen 34-51 or 10 atoms = 10 — _ 34-64 100-OOt 28-875 100-00 SECTION IX. — OF GLYCERIN. This substance was discovered by Scheele, and called by him sweet principle of oils. He showed that it is evolved when an oil is boiled with oxide of lead and a little water.J The watery portion holds the glycerin in solution. If we deca.^t off this water and • I had detected its peculiar nature and characters thirty years before ; but chemists had not attended to the facts which I stated. See the different editions of my System of Chemistry. t Ann. de Chim. et do Phys. H. 198. % Scheele, Opusc. ii. 189. 1 '1 I* ' ;i! H G4U HU(iARS. throw down the oxide of load whi(*li it contains by sulphuretted hydrogen, and then evaporate, we obtain the glycerin in a state of purity* Chevreul after wardM showed that it is separated whenever an dil is converted into Hoap." And from subsequent experiments of various chomiMts, there seems reason to conclude, that when an oil is uaponitiod it is docompotied into two substances ; namely, glycerin and margaric acid, oleic acid, or some one of the other soap- making acids. To obtain glycerin wo have only to digest an oil with an alkaline ley till wo convert it into soap. The soap being separated, the alKalino liquid remaining is saturated with sulphuric acid, and any excess of acid is removed by carbonate of oarytes. Filter and evaporate to the consistence of a syrup. Dissolve the syrup in alcohol, and filter in order to separate the alkaline sulphate. When the alcoholic solution is evaporated, the glycerin is obtained in a state of purity. Thus obtained, it is a colourless syrup, uncrystallizable, but capable of being converted into a white solid substance. Its taste is sweet, but it is destitute of smell. When concentrated till its speciHc gravity is I '2.52, it still retains water. Chevreul kept it for two months in the vacuum of an air pump along with sulphuric acid. Its specific gravity became 1*27, but it still retained water. Accord- ing to Pelouze, its specific gravity, when anhydrous, is 1 '280.1 It attracts moisture from the atmosphere and dissolves readily in alcohol. When heated in a retort the greatest part of the glycerin may be distilled over unaltered ; but when the retort begins to get red hot, a liquid passes over containing acetic acid and a black empyreumatic oil, while a charry matter remains in the retort. In the open air glycerin burns with a blue flame. Though almost solid it possesses a solvent power, scarcely inferior to that of water itself. It dissolves the vegetable acids, the deliquescent salts, and many other salts that are not deliquescent, as sulphates of potash, soda and copper, nitrates of silver and potash, the alkaline chlorides, and potash and soda in great quantity. Nitric acid converts it into oxalic acid ; but very slowly. Dissolved in 4 times its weight of water it undergoes no alteration, and does not ferment even when mixed with yeast. With potash it forms a compound soluble in alcohol. It is not precipitated by subacetate of lead, and is itself capable of dissolving oxide of lead. Chevreul found the constituents of glycerin, specific gravity 1*27, to be Carbon 40-071 or 3 atoms = 2*25 or per cent. 39' 13 Hydrogen 8'925 or 4 atoms = 0-5 _ — 8'(i9 Oxygen 51*004 or 3 atoms = 3-0 _ — 52-18 lOO-OOOt 5-75 100 Siir Ics Corps Gras, p. 209. t Aim. de Cliim. et de Phys. Ixiii. 19. X Sur Ics Corps Gras, p, 340. OLYCBRIN. 647 Lieblg'a analysis led liini to consider glycerin m composed of 6 atoms carbon = 4*6 or pur cunt. 43'37 7 atoms hydrogen = 0*875 — - — 8*43 5 atoms oxygen =5 — — 48*20 10*375 100*00 There can \w little doubt that these numbers constitute a near ap- proximation to the constitution and atomic weight of glycerin. If we adopt the view presented by Liebig and Pelouzu, fi'om their analysis of stearin, which they find composed of C'*' H'** O", and which they consider as composed of 2 atoms stearic acid . C>" II'" 0»» 1 atom glycerin . . C « H » O » 2 atoms water • , , H ' O * C'« H'" O'^ we must consider I atom of glycerin as combined in stearin with 2 atoms of stearic acid, in which case 1 0*375 will be its true atomic weight, and Liebig's atomic numbers tlie true number of atoms which enter into its constitution. 1" 1 f The plants containing sugar are very numerous. Margraff first pointed out a method of separating it irom them. The plant sus- pected to contain it is reduced to powder or pulp, and boiled with strong alcohol. The liquid is filtered while hot, and set aside in a close vessel. In a few days the sugar separates from the alcohol and crystallizes.* The following are the chief plants from which it has been actually extracted by chemists :t The flower of the rhododendron ponticum The sap of the acer sacchurinum ■ betula alba asclepias syriaca — — heraclium sphondilium cocos nucifera juglons alba agave Americana! ■ fucus saccharinus ficus carica ceratonia siliqua§ The juice of arundo saccharifera arundo bambosll zea mays The roots of pastinaca sativa^ • Margraff, Opusc. i. 216. f See Gren's Handbuch, ii. 123. t Margraff, Opiisc. i. 213. § Klaproih, Gchlen's Jour. iv. 326. II Tcnnant's Indian Kecreation, ii. 268. K Margraff, Opusc. i. 213. I i 648 SUGARS. :.| The roots of slum sisarum* beta vulgaris and cicla* daucus carota* apium petroselinum , The bulb of the allium coepe. It is proper to observe, however, that from the daucus carota^ Margraff could obtain only an uncrystallizable syrup. The sugar from the sap of the agave Americana bore a greater resemblance to manna than to sugar.f It is very seldom that sugar exudes spon- taneously from vegetables ; sometimes, however, it does. Tears of a sweet substance were observed upon the ceratonia siligua, or locust tree, some time ago in Naples. These tears were examined by Klaproth, and found to be sugar mixed v/ith a little tannin and oxalate of potash.J The inspissated juice of the bamboo {arundo bambos) is known in India by the name of sacar nambu ; a term which is supposed to be the origin of our word sugar, and con- stitutes a species of sugar celebrated as a medicine. How far it agrees with common sugar has not been ascertained. Small crystals of sugar are found occasionally in the flower of the rhododendron ponticum. I have received some of these crystals from my friend Dr Charles Mackenzie, but too small in quantity to admit of a rigid examination. They have no regular shade ; but in other respects seem to agree with common sugar in their properties. The same sugar has been noticed by Fourcroy, Vauquelin, and Bosc.§ The list of the saccharine plants would be greatly extended were we to add all sweet-tasted fruits, such as grapes, &c., which obviously contain sugar, and some of the mushroom tribe, from which Hum- boldt affirms he extracted it.|| Sugar has now become an essential part of the food of Europ- eans. It contains perhaps a greater proportion of nourishment than any other vegetable substance in the same bulk. It has the advan- tage of most other articles of food, in not being liable to be injured by time nor by the weather. If we believe Dr Rush, the plentiful use of it is one of the best preventatives of the diseases occasioned by worms. It has been long supposed to have a tendency to injure the teeth ; but this prejudice is now given up. It has the property of preserving other vegetable substances from putrefaction ; and accordingly is often employed for that purpose, constituting the base of conserves, &c. * Margraff, Opusc. i.213. f Margraff, i. 241. | Gehlen's Jour. iv. 327. § Ann. de Chim. Ixiii. 102. |[ The reader will find a much fuller list than I have given, in John's Tabellen, p. 11. I have not ventured to make use of his materials, because I have no means of determining the particular species of sugar which each vegetable contains. AMYLACEOUS SUBSTANCES. 649 CHAPTER V. OF AMYLACEOUS SUBSTANCES. and If a quantity of wheat flour be formed into a paste, and then held under a very small stream of water, kneading continually till the water runs off" from it colourless, the flour by this process is divided into two distinct constituents. A tough substance of a dirty-white colour, called gluten, remains in the hand ; the water is at first milky, but soon deposits a white powder, which is known by the name of starch. A sweet-tasted mucilaginous substance remains dissolved in the water. The starch obtained by this process is not altogether free from gluten ; hence its colour is not very white, and it has not that fine crystallized appearance which distinguishes the starch of commerce.* Manufacturers employ a more economical and more efficacious process. Good wheat is allowed to steep in cold water till it be- comes soft, and yields a milkv juice when squeezed. It is then taken out of the water ; put Jito coarse linen sacks, which are sub- jected to pressure in a vat filled with water ; a milky juice contain- ing abundance of starch exudes, and mixes with the water of the vat. This process is repeated as long as the wheat yields any milky juice. The sack and its contents are then removed. The starch soon falls to the bottom of the vat ; and the water which covers it gradually ferments, in consequence of the substance which it holds in solution. Alcohol and vinegar, or lactic acid, are formed in it, partly, no doubt, at the expense of the starch. The acid, thus evolved, dis- solves all the impurities, and leaves nothing behind but starch. It is then poured ofi^, and the starch edulcorated with water. It is after- wards dried by a moderate heat. During the drying it usually splits into small columnar masses, which have a considerable degree of regularity. The water which has stood over the starch was analyzed by Vauquelin. It contains a considerable portion of alcohol and of acetic acid. The acid holds in solution gluten somewhat altered, phosphate of lime, and ammonia.f Starch was well known to the ancients. Pliny informs us, that the method of obtaining it was first invented by the inhabitants of the island of Chio.J There is a considerable number of substances, which have so great a resemblance to starch, that they have been classed along * Its colour may be much improved by digesting it in an alkaline ley of moder< ate strength. f Ann. de Chim. xxxviii. 248. See La Fabrique de I'Araidon, by Du Hamel do Monceau. See also Gmelin's Handbuch der Technischen Chemie, ii. 737. Tiie reader will find a description of the process followed by our manufacturers in making starch, in Phil. Mag. xxix I6G. X Lib. xviii. cap. 7. 650 AMYLACEOUS SUBSTANCES. with it by chemists. It will be proper to take a view of all these substances here. This Chapter therefore will be divided into nine Sections. SECTION i. — OF COMMON STARCH. Common starch is extracted from wheat by the process described in the beginning of this Chapter. But the purest; starch of all is procured from the potatoe, simply by rasping it down over a seirce, and passing a current of water over the raspings. The water passes through the seirce milky from the starch suspended in it. The starch is allowed to fall to the bottom, and is two or three times washed with pure water. It is then allowed to dry. 1 00 parts of good potatoes, when treated in this way, furnish, according to the experiments of Einhoff, about 15 parts of starch. Besides wheat and potatoes, starch exists in a great number of other vegetables, all the seeds of grassy plants used for food, as oats, rice, rye, barley, &c., contain it. It exists in most bulbous roots. Thus, besides the potatoe, the convolvulus batatas and eduliSy the helianthus tuberosus^ the latropha manihot, &c., may be mention- ed. Arrow-root* consists entirely of very pure starch. It is ex- tracted from the roots of the maranta arundinacea (Monandria Monogynia)y a plant which is a native of South America and of Jamaica, and, as Dr Joxburgh informs us, from those of the curcuma angustifolia (also Monandria Monogynia), which is a native of Malabar. The maranta is about two feet high, has broad-pointed and somewhat hairy leaves, and bears small white flowers in clusters, and globular fruit of the size of currants. The roots are dug when a year old, well washed and beaten in deep wooden mortars, till they are reduced to a milky pulp. This is well washed in clear water, and the fibrous parts of the root being carefully separated, nothing remains but the starch, which is passed through a coarse cloth, and the liquid allowed to settle. The water is drawn off" and the starch washed repeatedly with water till quite clean. The starch is then dried in the sun. Arrow-root is very pure starch, and the maranta yields a greater quantity of this principle than most other vegetable bodies. In commerce it is said that potatoe starch is frequently sub- stituted for arrow-root. The substance imported into this country from South America, and known by the names of Cassava and Tapioca, is also a very pure starch. It is obtained from the roots of the jatropha manihot {Moncecia Monadelphia), a native of South, America. These roots are peeled and subjected to pressure in a kind of bag made of rushes. The juice that is forced out is a deadly poison (containing strych- nina), and is employed by the Indians to poison their arrows. But it deposits gradually a white starch which, when properly washed, is innocent. What remains in the bag consists chiefly of the same * So called because it is considered as an antidote to the poisoned arrows of the Indians. COMMON STARCH. 651 isoned arrows of starch. After being thoroughly washed, it is dried in smoke, and afterwards granulated by being forced through the meshes of a kind of sieve. Sago is an- -r variety of pure starch which is extracted from the pith of a species of palm called Sagus raphia, which grows in the Moluccas, Philippines, ana other East India islands. The palm is cut into pieces of tive or six feet in length : the woody part is cut off one side, exposing the pith lying, as it were, in the hollow of a canoe. Cold water is poured in, and the pith well stirred ; by which means the starch is separated from the fibrous part, and passes through with the water when the whole is thrown on a seirce. The sago, thus separated, is allowed to settle ; the water is poured off; and when it is half dry it is granulated, by being forced through a kind of funnel. It is said to acquire its grey colour while dried in an artificial heat. This substance is employed as an article of food, and its nourishing properties are well known.* Salop is another variety of starch, which comes to this country from Persia ; but is said also to be manufactured in Europe. It is supposed to be the prepared roots of different species of orchis, as the morio, mascula, bi/olia, pyramydalis. According to Moult, the bulbous roots of these plants are deprived of their cuticle, baked in an oven for 10 or 12 minutes, which gives them the semitranspar- ency, and then fully dried in a moderate heat.f Like sago, salop is used only as a nourishing article of food. It is said by Dr Per- cival to have the property of concealing the taste of salt water.J The very nutricious article of food distinguished in Scotland by the name of soioans, and in England cqWqH flummery, is made from the husk of oats, by a process not unlike that by which common starch is made. The husk of the oat (called seeds) is separated from oatmeal by the sieve. It still retains a considerable portion of farinaceous matter. It is mixed with water, and allowed to remain for some days till the water has become sour. The whole is then thrown upon a seive. The milky water passes through ; but all the husk remains behind. The water thus obtained is loaded with starchy matter, which soon subsides to the bottom. The sour liquor is decanted off, and about an equal quantity of fresh water added. This mixture when boiled forms a very nourishing article of food ; and the portion of the sour water which still adheres to the starch gives the whole a pleasant acidity. It is curious enough that the starch-maker's water, notwithstanding the great quantity of acid which it contains, likewise the still sourer water of sowans, are swallowed greedily by hogs. They fatten upon it. Starch, when pure, has a fine white colour, no smell, and very little taste. When kept dry it continues long unaltered though exposed to the air. When squeezed between the fingers it gives a peculiar sound. Its specific gravity, as stated by Raspail, is 1*53. * Forest's Voyage, p. 39. f Phil. Trans, lix. 2. X Phil. Mag. xviii. 161. m ■ I f 1 ' MW ^ il 652 AMYLACEOUS SUBSTANCES. When examined under the microscope, it appears under the form of rounded grains, which vary in their shape, not only when the starch is extracted from different plants, but even from the same plant. They are lodged in particular cells in the plant, which pro- duces them and increase in size as the plant advances to maturity. According to Raspail, they consist of vesicles inclosing within them a clear transparent colourless liquid. In cold water these vesicles remain entire and insoluble ; but when put into boiling water they burst, the central liquid dissolves in the water, and the husk or outer coat of the vesicle becomes much more bulky and transparent than it was before, and floats undissolved in the liquid. Heat causes these vesicles to burst, and to empty themselves of the liquid which they contain.* Thus it appears that starch consists essentially of two distinct substances. 1. The liquid portion which fills each little vesicle. This liquid portion consists of water, holding in solution a peculiar substance, which M. Guerin-Varry, to whom we are indebted for an examination of its properties, has distinguished by the name of arnidin.^ 2. The vesicular portion of the grain, which is insoluble in water, may be distinguished by the name of amylin.X We must consider the properties of each of these sub- stances separately. According to the experiments of M. Guerin-Varry, potatoe starch is composed of Exterior tegumentary ai Amidin . Amylin . myl m 2-12 38-13 59-75 100-00§ 1 . Amidin. Amidin^ or the soluble part of starch, may be obtained in the following manner: — Put 1 part of potatoe starch into 100 parts of water, and boil the mixture for a quarter of an hour, and then pour the whole into a precipitating glass. By degrees the integu- ments of the vesicle of the starch precipitate to the bottom of the vessel. Decant off the clear liquid, filter it, and boil it gently down to the consistence of a syrup. Pour this syrup upon a cloth and squeeze it through. The triticin is retained by the cloth ; but a liquid passes through, which must be evaporated by the vapour-bath, at a temperature below 212°. Some amylin is deposited. We must filter again to get rid of it, and evaporate anew. These alternate filtrations and evaporations must be repeated as long as any amylin continues to appear. The liquid is now evaporated to dryness. It leaves a substance completely soluble in cold water. This new solution is deprived of its colour by animal charcoal, purified and * Chimie Organique, p. 6. f Ann. de Chim. et de Phys. Ivi. 231. X M. Guerin-Varry has called it amidine, but this name is too near amidin^ when pronounced in the English way to enable us to distinguish the one substance from the other. I have therefore been obliged to employ a new term and I have adopted amylin, from the Greek word afivXtt, starch, as sufficiently appropriate. $ Jour, de Pharmacie, xxii. 210. COMMON STAACH. 653 precipitated by alcohol, thrown upon a filter, and washed by alcohol at the temperature of 186°. It is finally dissolved in as little water as possible, and evaporated to dryness over the vapour-bath. Amidin thus obtained is a very light substance, yellow when anhydrous, but white when it contains water. It has neither taste nor smell. When in thin plates it is transparent ; and is easily reduced to powder. M. Biot examined its action on polarized light, and found that it caused a deviation of the rays to the right, about three times as great as common sugar — a deviation which is sensibly the same with that of his dextrine. When heated it melts and swells up, but is not volatilized. Cold water dissolves it, and acquires the consistence of mucilage. It is slill more soluble in boiling water. In alcohol and ether, it is quite insoluble. It adheres very firmly to the glass or procelain vessel, in which its aqueous solution is evaporated. Its aqueous solution acquires an acid taste in a few days, and becomes very slightly muddy. When digested in nitric acid, it forms first oxalhydric acid, and finally oxalic acid. 100 parts of amidin, and 250 parts of sulphuric acid at the tem- perature of 150°, furnish, according to the experiments of M. Guerin- Varry, 95*8 parts of anhydrous sugar. According to the experiments of the same chemist, amidin is com- posed of Water 3'0 Ashes .... 0'2 Pure amidin .... 96*8 100-0 He analyzed pure anhydrous amidin, and obtained Carbon 39-72 or 10 atoms = 7-5 Hydrogen 7-13 or I Of atoms = 1-34 Oxygen 53-15 or 10 atoms = 10-0 M. 100-00 18-84 Guerin has examined also the amidin from the starch of potatoes, and states its composition to be C* H'" O®.* He dried it in vacuo at 265°, and found its constituents Carbon 53-23 or 14 atoms = 10-5 or per cent. 53-16 Hydrogen 6-27 or 10 atoms = 1-25 — — 6-33 Oxygen 40-50 or 8 atoms =8 ~ _ 40-51 100-00 19-75 loot But from the experiments of Prout, I think it more probable that the constituents are * Jour, de Pharmacie, xxii 210. f Ann. de Clum. et de Phys, Ixi. 86. 654 AMYLACEOUS SUBSTANCES. !1f I* ' I ': ; 1 I, 1 ; 1 i:« 1 *'i ( ■ *• * il R* J ?i 'I II t ■ ^i 10 atoms carbon 10 atoms hydrogen 10 atoms oxygen 7*5 or per cent. 40*00 1-25 — — 6-67 10-0 — — 53-33 18-75 100-00 If 18*75 be the atomic weight of amidin, then the hydrous amidin analyzed by M. Guerin-Varry contained about half an atom of water, or was composed of 2 atoms amidin 37*5 or per cent. 97-08 1 atom water 1-125 — — 2-92 38-625 100 2. Amylin. Amylin, or the portion of starch which constitutes the outer covering of the spericles, and which is insoluble in water, possesses the following characters, as they have been investigated by M. Guerin-Varry : — When dried at the temperature of 212°, it is slightly yellow. The pellicles of which it is composed are easily reduced to powder. It gives a fine blue with solution of iodine. When the liquid is heated to 194°, this colour vanishes, but it appears again when the liquid cools. Though kept for 100 hours, in 10,000 times its weight of boiling water, it does not dissolve, nor is it resolved into globules, as Raspail, and Biot, and Persoz affirm it to be. It is insoluble in water, both cold and hot, in alcohol, and in ether. But it swells in water, becomes white, and shows a certain degree of elasticity. When 100 parts of amylin are digested with 800 parts of nitric acid, 25-46 parts of anhydrous oxalic acid are formed. When digested for 1 2 hours, with 2^ times its weight of sulphuric acid, at the temperature of 151°, we obtain a syrup, which, being boiled for 12 hours, with 200 times its weight of water, is converted into starch sugar. Some vegeto-sulphuric acid is formed at the same time. 100 parts of amylin treated in this way gave 88-92 parts of anhydrous, or 110-57 parts of hydrous sugar. Amylin, according to the analysis of M. Guerin-Varry, is com- posed of Water 10-99 Ashes . . . . . 1-00 Real amylin .... 88-01 100-00 Being analyzed by means of oxide of copper, it yielded Carbon 52-74 or 17 atoms = 12-75 or per cent. 52-31 Hydrogen 6-59 or 13 atoms = 1-625 — — 6*66 Oxygen 40-67 or 10 atoms = 10-00 — — 41-03 100-00 24-375 100-00" • M. Guerin-Varrv has analyzed the amylin from potatoe starch, and says that it is composed of C* H'" O'^ See Jour, de Phurm. xxii. 210. I 1 COMMON STARCH. 655 He afterwards dried amylin in vacuo^ in the temperature of 275°, and obtained from it* Carbon 52-80 or 10 atoms = 7*5 or per cent. 53-10 Hydrogen 4-35 or 5 atoms = 0-625 — — 4-42 Oxygen 42-85 or 6 atoms = 6-0 — — 40-48 100-00 14-125 100-00 But I am persuaded that these numbers do not constitute very near approximations to the truth. Dr Prout analyzed pure wheat starch and arrow root, with every possible attention to accuracy. He found the constitution as follows : — Wheat Starch. Arrow Root. 36-400 7-066 56-534 37-5 6-94 55-56 100-00 100-000 Carbon Hydrogen Oxygen These substances were expoSed for 20 hours to a temperature of between 200o and 212°: the wheat lost 12-5, and the arrow-root 15 per cent, of their weight. Being now analyzed, the constitution of both was identical, being composed of Carbon .... 42-800 Hydrogen .... 6-355 Oxygen .... 50-845 100-000 The wheat starch being exposed for 6 hours more, to a heat between 300o and 350", lost 2-3 per cent, more of its weight, and was com- posed of Carbon .... 44 Hydrogen .... 6-22 Oxygen .... 49-78 100-00 The starch had now acquired a slightly yellow colour, and seemed to have suffered some change in its properties. Hence 14-8 per cent, seems to be about the utmost quantity of water that dry wheat starch can part with, without decomposition. The arrow-root subjected for 6 hours longer to a heat between 300° and 350°, lost 1-38 per cent, more of its weight, or in all 16-38 per cent. ; but it had now assumed a deep yellow colour, and was altered in its properties.! Now in these experiments, the amidin and amylin were con- founded together. Yet as the hydrogen and oxygen occur always in the proportions which constitute water, it is obvious that the * Ann. de Chim. et de Phys. bti. 84. f Phil. Trans. 1827, p. 376. ;i ;) . i 656 AMYLACEOUS SUBSTANCES. ; i t! number of atoms of hydrogen and oxygen, must either be equal both in amidin and amvlin ; or that whatever preponderancy of either shall occur in amidin, the opposite preponderancy must occur in amylin. But in M. Guerin-Varry's analysis, there is a prepon- derancy of hydrogen, both in amidin and amylin. Dr Front's analysis of wheat flour, dried in a temperature between 300° and 350°, leads to the conclusion that its constituents were 12 atoms carbon =9 or per cent. 44*44 10 atoms hydrogen = 1'25 — — 6*17 10 atoms oxygen =10 — — 49*39 20*25 100*00 Now if amidin be composed of 10 atoms carbon, 10 atoms hydrogen, and 10 atoms oxygen, it is probable that the above numbers very nearly represent the atomic constitution of amylin. The late experiments of Payen, made with very great care, approach pretty nearly to those of Prout. He obtained from pure amylin, dried at 130°, Carbon .... 43-31 Hydrogen . . . . 6*49 Oxygen .... 50*20 ^ 100*00* Numbers which lead obviously to the conclusion, that amylin is a compound of 12 atoms carbon, 10 atoms hydrogen, and 10 atoms oxygen. It is probable that the dextrine of Biot and Persoz consists chiefly of amidin. But M. Guerin-Varry has shown that the dextrine of these gentlemen, is not a single vegetable principle, but a mix- ture of several. They have stated as an essential chemical pro- perty of dextrine, that it ferments when mixed with yeast. M. Guerin-Varry prepared a quantity of dextrine by their process, and found, as they had stated, that it fermented with yeast. He digested it in alcohol, and extracted a sweet-tasted substance, which ferment- ed abundantly with yeast. But the residue which was insoluble in alcohol, did not undergo the least fermentation when mixed with yeast. Iodine gave it a blue colour, though Biot and Persoz state that iodine gives dextrine the red colour of wine. When the por- tion of dextrine insoluble in alcohol is put into water, one portion of it dissolves while another portion remains undissolved. It would appear from this, to be a mixture of sugar, amidin, and amylin, and probably of other substances.f Payen obtained a quantity of pure dextrine, by a very laborious process.* When pure it dried readily into scales or plates, which did not adhere to porcelain or glass dishes. Being analyzed by M. Payen, he obtained Ann. de Chim. et de Fhys. Ixi. 371. X Ibid. Ixi. 372. t Ibid. Ivi. 239. lal both f either ccur in propon- Prout's 00° and ^drogen, ers very jat care, rom pure (lylin is a 1 10 atoms ists chiefly iextrine of ut a mix- nical pro- ;ast. M. ocess, and [e digested h ferment- (isoluble in aixed with ersoz state !n the por- »ne portion It would ,mylin, and y laborious ites, which .nalyzed by Ivi. 239. HORDEIN. 657 Carbon Hydrogen Oxygen 42*24 6-20 51-56 100-00 These numbers approach so nearly the constituents of amylin, as to leave no doubt of the identity of the two substances. SECTION II. — OF HORDEIN. This substance was first noticed and described by Proust in 1817.* It may be obtained from barley-meal by the following process : — Make the barley-meal into a paste with water, and wash it by a current of water dropping on it. The starch and hordeiti are washed away. If we boil tnis mixture in acidulous water, the starch is taken up, and the hordein remains unaltered. It amounts, accord- ing to Proust, to from 54 to 56 per cent, of the barley meal em- ployed. It is a yellow powder, granular to the touch, and has very much the appearance of sawings of wood. It is insoluble hi water and alcohol, does not yield ammonia when distilled, and when treated with nitric acid, it furnishes oxalic acid, acetic acid, and traces of a bitter substance. According to Proust, during the malting of barley, the hordein is converted into starch. Hordein has been subjected to analysis by M. Marcet. He found its constituents Carbon ..... 44-2 Hydrogen .... 6*4 Azote 1-8 Oxygen . . . . 47-6 100-Ot As hordein yields no ammonia when distilled, the probability is, that the 1*8 per cent, of azote found by Marcet, proceeded from an admixture of common air. If we leave out the azote, the other con- stituents approach 12 atoms carbon 1 1 atoms hydrogen 10 atoms oxygen. But, as in the other substances analogous to starch, the oxygen and hydrogen exist in the proportions requisite to form water, it is pro- bable that this is the case also in hordein, and that the true con- stituents are 12 atoms carbon =9 or per cent. 44*44 10 atoms hydrogen = i-25 — — 6-17 10 atoms oxygen =10 — — 49*39 20-25 • Ann. de Chim. et de Phvs. v. 339. 100 f Mem. de la Societe Physique et d'Histoire Naturelle de Geneve, Hi. 317. 2 u I] I .ill I i; 658 AMYLACEOUS SUBSTANCES. Now this ia the very constitution of ainylin deduced from the analyses of Prout and Payen. We are indebted to M. Marcet also, for an analysis of the starch of malt, the substance into which hordein i8 converted, according to Proust, during the process of malting. He found the constituents as follows : — Carbon 41 '6 Hydrogen .... 6*6 Oxygen 51*8 100-0 These numbers correspond with 1 1 atoms carbon = 8*25 or per cent. 42*30 10 atoms hydrogen = 1*25 — — ()'41 10 atoms oxygen =10 — — 5 1 "29 19-5 100-00 If any confidence can be placed in this analysis, the hordein, during the process of malting, loses one atom of cuibon. Hence doubtless, in part, the cause of the evolution of carbonic acid gas, which takes place during the process of malting. SECTION III. — OF LICHENIN. This name has been given by M. Guerin-Varry to what was formerly called the starch of the cetraria islandica, or Island moss* well known as the food of the rein-deer. Good cetraria islandica contains about 44^ per cent, of lichenin. It may be extracted in the following way : — Minch the lichens very fine, and for every pound of lichen take 18 pounds of water, in whicli about an ounce of common pearl ash has been dissolved. Let the lichen macerate for 24 hours in the water, taking care to stir it about frequently during this interval. The alkali dissolves a bitter matter, almost insoluble in water, and the liquid acquires a brown colour. Throw the whole upon a cloth, and let the liquid drain off from the lichen. Macerate it again in an additional quantity of water, and repeat the maceration till all the bitter principle and potash are re- moved. We must not expose the lichen to pressure, because a good deal of the lichenin would be forced out along with the water. Boil the lichen thus purified (supposing 1 lb. employed) in 9 pounds of water, till they are reduced to 6 pounds. Filter the liquid while hot through a cloth, and subject the residue to pressure. The liquid thus obtained is, while hot, limpid and colourless. On cool- ing, it becomes covered with a pellicle, and at last the whole is con- verted into a grey-coloured, opaque jelly, which contracts by degrees, cracks in all directions, and separates from the water in which it was diissolved. When laid upon blotting paper, this liquid separates by little and little, and the jelly remains. When quite dry it has a * Herberger has given it the name of ce/rarin. It was first examined by Berzeliu^, who obtained it, but not absolutely pure. MCIIBNIN. 659 am the 5 starcli •ding to tituentft n, during loubtlcss, lich takes what was md mosSy* if lichenin. chens very sr. in which Let the itir it about tter matter, »wn colour. )ff from the water, and tash are re- lause a good vater. Boil n 9 pounds liquid while (sure. The i. On cool- irhole is con- j by degrees, in which it uid separates dry it has a eil by Berzelius black colour, is hard, and breaks with a vitreous fracture. The black colour ia owing to the presence of an extractive matter, ren- dered insoluble in water by the preceding treatment. If, therefore, we dissolve the matter in boiling water, wo obtain, when the liquid cools, a colourless, but opaque jelly, which, when dry* is pure lichenin. Lichenin thus obtained has little taste, but a slight smell of lichen, which adheres to every thing extracted from lichens. When dry it is yellowish ; but while it retains water its colour is white. When in thin plates it is transparent. Tough. When put into cold water it swells up into a kind of jelly, but does not dissolve. In boiling water it dissolves into a mucilage, constituting a jelly when much concentrated. It is coloured blue by iodine, but much less intensely than amylin. The aqueous solu- tion of lichenin is precipitated in white flocks when mixed with al- cohol or ether. Water redissolves the alcoholic, but not the ether deposit. The aqueous solution of lichenin exposed to the air be- comes acid in a few days. Diacetate of lead dropt into an aqueous solution of lichenin, forms a copious precipitate, insoluble in water, but soluble in acetic acid. According to Herberger, lichenin possesses alkaline properties combining with acids, but its salts are incapable of crystallizing.* When 100 parts of lichenin are digested with 250 parts of sul- phuric acid at 151°, and then treated in the usual way, we obtain 93'91 parts of anhydrous starch sugar. 100 parts of lichenin digested at 70°, with GOO parts of nitric acid of the specific gravity 1'34, for 28 days, and then heated to 104°, gave a great deal of oxalhydric acid. Being afterwards heated to 140°, and then allowed to cool, it gave 48*17 parts of oxalic acid.t The constituents of hydrated lichenin, according to the analysis of M. Guerin-Varry, are Water ..... 7 Ashes 0*8 Lichenin ..... 92*2 100-0 He subjected anhydrous lichenin to an analysis, by means qf oxide of copper, and obtained Carbon 39*33 or 10 atoms = 7*5 or per cent. 39*74 Hydrogen 7*24 or 11 atoms = 1*375 — — 7*28 Oxygen 53*43 or 10 atoms = 10*0 — — 52*98 100-OOt 18*875 100 But the circumstance rendering the accuracy of this analysis of lichenin doubtful is, that it exhibits 11 atoms of hydrogen to 10 of oxygen ; while we have seen that the previous experiments of Thenard and Gay-Lussac, and of Dr Prout, render it exceedingly probable, that in all the varieties of starch these two constituents * Jour, tic Pharmacic, xvii. 229. f Guerin-Varry, Ann. de Chini. et de Phys. Ivi. 247. t Ibid, p. '<;48. I cno AMYLACROUS DUDIITANCen. ill N i I exist in the proportions recpiisito for forming water. Probably the true constitution of lichenin \h 10 atoms carbon = 7*5 or per cent. 40*00 10 atoms liydrojfon = 1*25 — — 6*07 10 atoms oxygon =100 — — 53'33 18-75 100-00 These numbers do not deviate far from the result of Ouerin- Varry'g analysis. If they are correct, they show that lichenin is in its con- stitution isomeric with aniidin, although the two substances differ somewhat from each other in their properties. Herberger has ob- served that it is poisonous.* SECTION IV. — OF INULlN.f This substance was first noticed and described, in 1804, by M. Valentine Rose, the friend and fellow-labourer of Klaproth.J Hp found it in the roots of the inula heleniiim, John obtained it ft mi tin- anthemis Pyrethrum ;^ Pelletier and Caventou, from the bullxdis roots of the colchiaim autumnale i\\ Payen from the tubers of tlie Dahlia pinnata and purpurea ;^ Hraconnot from the heliant/ius tuberosus, and the roots of the Datisca cannobina;** and Tr'jmmsdorf from the Menyanthea trifoliata.^] When the roota of the iimla helmium are boiled in water, the decoction, after standing some hourt^, deposits the inulin in thu IVirm of a white powder like starch. The dahlia purpurea yields it in greatest abundance; but it is with equal ease extracted from the roots of the inula helenium and hdiauthus tuberosus. The roots are rasped down and boiled with wa tcr. The boiling-hot solution is passed through a cloth, and, if muddy, is clarified by the white of an egg. It is then evaporated till a pellicle begins to api)ear on the surface, and allowed to cool. The inulin is deposited in the form of a white powder. Let it be collected on a filter, washed, and dried. The roots of inula helenium contain I l?,th per cent, of helenium ; those of leontodon taraxicum 12 per cent.; and those of cichorium intybus 12^th per cent. Inulin is a fino white powder, destitute of taste and smell. Its specific gravity is l-SSG.Jt When heated a little above 212° it gives out water, and enters into fusion. On coolintj, it assumes the form of a grey, scaly mass, f>isily reducible to pu'.vilcr la this state it * Jour, do Pharmacie, xvi' 1'^? f Inulin has been distinguished by various nav > . jhn tailed it Helenin ; Trommsdorf, Alantin and Menyanthin ; Henry, Elecampin ; I'ayen, Dahlin and datiscin ; obviously from the names of the plants in which it has been de- tected. X Gehlen's Jour. iii. 217. (J Chom. Schriftcn, iv. 126. II Ann. de Chim. et do Phys. xiv. 09. T Jot;- de Php,r«iucio, ix. 383. The dahlia purpurea, on the Continent, is called iiiorgina i^urpureu. *♦ Vnu. de Chim. et de Phys. iii. 278 ; and xxv. 357. f f Jour, de Pharmacie, xviii. XX Berzelius, Traite de Chemic, v. 209. MdNIN. on I lia8 u Bwoct and jjumuiy 'aate, and alcohul uxtracttt from it a brown matter, loavinj^ a mnn v«»ry Koluhlo in water. When »trongly Iieatcd it behaves like starch, and yields no einpyri'i.matit; oil. lodino j^ivesi it a yellow owlour, and rcndoru it iiisohihle in water. loo parts of cold water ili:*»oUo3 oiiIn 2 parts of iiiiiiliii ; but it in very soiid)le in boiling' water, and •rms with it a ujucilaue, which, however, has not the eouaiatonco of muciliigif* of starcii. When we evaporate tiie solution the iniiliii colUMts at the surt'ice of the liquid, under tho form of a iMucila ■ SECTION VIII. — OF OLIVILIN. This substance was discovered by Pelletier in 18 Hi, while ex- amining an exudation from the oliva Eurupea, or common olive tree in the southern ])arts of Italy.* In Calabria, this exudation bears the name of Lccca f/um, from a town in that country near which it occurs abundantly. It was known to the aHcients, who employed it in dressing sores. Olivilin may be obtained by the following process : — Digest the so called gum of the olive in ether, in order to remove a resinous matter which it contains. From the undissolved portion absolute alcohol dissolves the olivilin, which is deposited in crystals on evjiporating the solution. It is white and brilliant, and has the aspect, of starch. It has no smell ; but its taste is at once sweet, bitter and aromatic. It melts when heated to 158°. When allowed to cool it puts on the ap- pearance of a resin, and is a non-conductor of electricity. When heated in a retort, it gives out no ammonia. It is but little soluble in cold water, and requires 32 times its weight of boiling water to dissolve it. When the decoction is allowed to cool, it becomes milky and remains long in that state. Boiling alcohol dissolves any quantity of it whatever, but it ismach less soluble in cold alcohol. Ether docs not dissolve it at all. Both fixed and volatile oils dissolve a small quantity of it when assisted by heat, but it is again deposited when the liquids are allowed to cool. * Ami. do Cliini, et dc Phvs. iii. 105, and li. 19G. I I contact of lupcraturo 3 parts of than that iniicUagc, jc reaction fi', with 39 J, })arts of sugar, r is formed he greatest b, about 50 kvoen 140'' does it act cr it be left , while ex- n olive tree lation bears jar wliich it employed it ;r to remove ved portion I in crystals It bas no J. It melts on the ap- ity. When \2 times its Jecoction is I that state, it it is macb t all. Botb I assisted by wed to cool. COLUMIUN. G09 Dilute sulphuric acid does not dissolve it, and concentrated acid chars it. Nitric acid dissolves it cold, and assumes a red colour. When the solution is heated it becomes yellow, and oxalic acid and carbnzotic acid are formed. Acetic acid dissolves it and the olivilin is not precipitated from this solution by water. The alkalies dissolve it with facility and without altering its nature. The aqueous solution of olivilin is precipitated by acetate of lead, and the precij)itate is soluble in acetic acid. Its constituents, determined by the analysis of Pelletier, are Carbon ()H'84 or (J atoms = 4*5 or per cent. ()3*72 Hydrogen 8-0() or 4JL atoms = 5025 — _ 7-90 Oxygen 28-10 or 2" atoms = 2 — -— 28-32 100-00 7-0025 100-00 SUCTION IX. — OF COLUMUIN. This principle was discovered in 1830 by M. Wittstock, in Columho root."* Two different vegetal)les yield a root, which is known in commerce by the name of colund)o root. One of them is called African colmnho, and the other American columho, or Marcetta columho, pointing out by these names the country from which the roots come. The African columho is tlie root of the cocciiliis pal- matus, which is abundant in the forests of Mozambique. The j)lunt that furnishes the American columbo, is still unknown to botanists. Columbin was obtained by Wittstockf in the following manner : — The root previously pulverized is digested in ether till every thing soluble is taken up. When the (ithereal solution is abandoned to spontaneous evaporation, the columbin is deposited in crystals. But by this process only a minute (piantity of columbin is obtained. To procure it in greater tpiantity, let the root be treated twice or thrice successively with alcohol, of the specific gravity 0*835. Mix these solutions, distil off ■Jths of the alcohol, and allow the residual liquid to remain at rest for some days. Crystals are deposited which may be collected by throwing the whole on a cloth and allowing tiic liquid portion to pass through. Let these crystals be washed in cold water, dissolved in alcohol, jind the solution digested with ivory black and filtered. When the solution thus treated is concen- trated, it deposits pure crystals of columbin. The mother liquor still contains abundance of the same principle. Let it be mixed with pounded glass and evaporated to dryness, stirring it constantly when it begins to become concrete. Digest this powder mixed with glass in ether, which dissolves wax, fatty matter, and columbin. Distil off the ether, and digest the residue in boiling acetic acid, which will dissolve the columbin and leave the other substances. If the " Poggendorf's Annalen, xix. 298. It appears, from a note in the Journal tie Pharmacie, xvii. 80, that M. Planche had obtained colurabin as early as 1811 ; though not in a state of purity. f Jour, de Pharmacie, xvii. 77. 670 OUMS. acid be evaporated the columbin separates in crystals. Eight ounces of columbo root furnished only 60 grains of columbin. It crystallizes in rhombic prisms. It is destitute of smell, but hns a very bitter taste. When heated it melts, and assumes the appear- ance of wax. When distilled it yields no ammonia. It possesses neither the properties of an acid nor alkali. At the ordinary temperature of the atmosphere, it is but very little soluble in water, alcohol, or ether. Yet these liquids dissolve enough of it to acquire a bitter taste. Boiling alcohol of the specific gravity 0*835 dissolves from ^^^ to ^'^th of its weight of it. It dis- solves also, though very sparingly in volatile oils. Sulphuric acid dissolves it, assuming first a yellow and then a red colour. When water is added to the solution the columbin is precipitated under the form of a rusty yellow matter. Nitric acid of 1*25 dissolves it when assisted by heat, without decomposing it, and the columbin is partly precipitated by the addition of water. Boiling acetic acid of the specific gravity 1*04 is the best solvent of columbin, and when the solution is concentrated the columbin is deposited in regular crystals. Muriatic acid has very little action on columbin. It dissolves unaltered in the caustic alkalies, and is precipitated again by the addition of an acid. It was analyzed by Liebig, who obtained Carbon 65'45 or 12 atoms = 9 or per cent. 64*87 Hydrogen 6*18 or 7 atoms = 0-875 — — 6*32 Oxygen 28*37 or 4 atoms = 4 — — 28*81 10000* 13*875 100*00 I I CHAPTER VI. OF GUMS. r I The name gum was originally applied to a thick transparent taste- less fluid which exudes from various trees and plants, and which gradually concretes into a solid substance when left exposed to the air ; but easily softens again when moistened with water. The gum most commonly used in this country is known by the names of gum arable and gum Senegal. It exudes from the acacia veray acacia arabica and acacia Senegal, but many other plants yield it, as the apple-tree, plum-tree, cherry-tree, &c. Many seeds of plants, lint- seed for example, when macerated in water, render the liquid thick and adhesive, converting it into what is called mucilage. When this mucilage is evaporated to dryness, it leaves a translucent matter behind it, similar in its properties to gum, and usually distinguished by the same name. * Foggendorf's Annalon, x\i. 31. ht ounces 11, but has e appear- poaacases 1 but very is dissolve he specific t. It dis- huric acid ir. When lied under dissolves it jolumbin is )est solvent jolumbin is little action lies, and is . 64-87 6-32 28-81 100-00 ARABIN. 671 3parent taste- rs, and which iposed to the sr. The gum names of guin I verttf acacia ield it, as the of plants. Unt- ie liquid thick oilage. When islucent matter f distinguished For the most careful examination of the different substances usually classed amonfj gums, we are indebted to M. Guerln- ry, who has published some elaborate papers on the subject.* * ney may without inconvenience be arranged under three different genera : namely, arabin, bassorin, and cerasin. These will form the subject of the following Sections : — SECTION I. — OF ARABIN. This name was applied by M. Chevreul, because gum arabic, the best known and most employed of all the gums, consists almost entirely of arabin. Gum arable comes to this country from the Levant ; but its use has been in a great measure superseded by gum Senegal. It is in small rounded di ops or tears, either colourless or having a light yellow colour. H''rd and easily pounded. It breaks with a vitre- ous fracture, and has a specific gravity of l-355.t When moistened it reddens litmus paper, and is said sometimes (though I have never met with it in that state) to have an acid taste. According to the ex- periments of M. Guerin-Varry, gum arabic dried in vacuo, at the temperature 257"^, loses 17-6 per cent, of its weight. Its constitu- ents, according to the analysis of the same chemist, are Arabin 79-4 Ashes 3-0 Water 17-6 100-0 The ashes consist of carbonates of potash and lime ; a trace of phosphate of lime, chloride of potassium, oxide of iron, alumina, silica and magnesia. ^he characters of arabin are the following : — It is colourless, tasteless, and destitute of smell. Fracture vitreous. Transparent. Friable when dry ; but very tough when allowed to imbibe water. When heated to between 282° and 392° it softens, and may be drawn out into threads. When kept in a dry atmosphere, it does not alter its nature ; but it becomes acid when kept long in a moist atmosphere. It is insoluble in alcohol, incrystallizable and incapable of under- going the vinOv:s fermentation. At 68° an aqueous solution of arabin, containing more than 17-75 parts of arabin to 100 of water, will not filter through paper. Nor will it filter at 212° if it contains more than 23-54 per cent. This solution is known by the name of mucilage. It is very viscid and glutinous, and may be employed as a paste. It is commonly used by the calico-printers to thicken their colours and mordants, to pre- vent them from spreading on the cloth. Mucilage may be kept for • Ann. de Chim. et de Phys. xlix. 248. t Its specific gravity, as determined by Herberger, varies from 1 -4600 to 1 '52.00. Jour, de Pliarmacie, xx. 4 i I . 1 ■ ,■ '■ Wm 1 ffi 8 Ita 11 1 ^k:1 m G72 UUMS. f years, without undergoing much change ; hut at last it becomes acid. When boiled with sulphuric acid in the usual way, it is converted into a sugar, which does not ferment when mixed with yeast, and which, therefore, is different from starch sugar, and seems to ap- proach manna. 100 parts of arabin, when heated with 400 parts of nitric acid, of the speciric gravity 1'339, form 16*88 parts of mucic acid, toge- ther with a little oxalic acid. When silicated ])otash solution is dropt into an aqueous solution of arabin, a white flakey i)rccipitate falls, even when the mucilage is very dilute. This precipitate consists of gum, silica, and potash, and there remains in solution a cc^mbination of gum and potash. By this reagent a very minute quantity of arabin, dissolved in water, may be discovered. When a concentrated solution of pcrchloride of iron is dropt into mucilage, the whole becomes a brown semitransparent jelly, which is not readily dissolved in water. We have three analyses of arabin. The first by Gay^ » ,ussac and Thenard, the second by Berzelius, and the third by Af. Guerin- Varry. The following table exhibits the results obtained by these chemists : — Gav.I.uaiinc & Tlieiiard.* Carbon Hydrogen . Azote Oxvgen These numbers approach pretty nearly to each other. As M. Guerin-Varry dried his arabin at a higher temperature than the other experimenters, we see the reason why his product of carbon exceeds theirs. The azote found alone by Guerin-Varry is in so small a quantity, that it cannot be considered as belonging to the constitution of arabin. The preceding numbers lead to the follow- ing atomic proportions for the constituents of arabin : — 12 atoms carbon = 9 or per cent. 42*11 1 1 atoms hydrogen = 1*375 — — 6*43 11 atoms oxygen =11*000 — — 51*46 m 21*375 100*00 Now, this is precisely the constitution of common sugar in crystals. Such are the characters and such the composition of pure arabin. It will be proper now to mention the principal gums that consist altogether or chiefly of arabin. ♦ Rccherches, Pliysico-Chimiqucs, ii. 290. f Annuls of Philosophy, v. 270. t Ann. 6c Chim. et de Phys. xlix. 260. AllAIHV. 678 1 . Cum arahic. It becomes oolourleaa when exposed to the sun, or when treated with ehh)rine water. Its constituents and specific •gravity have been jjiven above. VVlien ah'ohol is boiU;d over gum arabic, it extracts biniahite of lime, chlorides of potassium and cal- cium, acetate of potash and chlorophyllin, together with a matter analogous to wax. 2. Gum sencynl has been shown by Perottet and Guillcniin to bo the produce of the acacia vcrc.k.* It comes from the west coast of Africa, and, being cheaper and equally useful, it has nearly sup- planted gum arabic in this country. Its specific gravity, as deter- mined by M. (fuerin-Varry, is l'43(i.f It occurs in much larger pieces than gum arabic, sometimes even as large as the fist, havmg an ovoid shape, and often hollow. It has a darker colour than gum arabic, but its properties are similar. 100 parts of water, at (>8°, dissolve 18*49 parts of it, while 100 parts of boiling watir dissolve 24' 17 parts. Boiling alcohol, chlorine, and aidphuric and nitric acids act upon it as on gum arabic. 100 parts of it, heated with 500 parts of nitric acid, furnish 10*7 parts of mucic acid, together with a little oxalic acid. Its constituents, determined by the analysis of M. Ouerin- Varry, are Arabin 81*1 Ashes 2'8 Water 16* Ij 100 The ashes are precisely similar to those of gum arabic. 3. Mucilaffe oflintseed. When lintseed is digested in hot water, and the solution obtained concentrated in a porcelain vessel over the water-bath, we obtain this mucilage. When dried it forms brown brittle crusts, having a peculiar smell, which Vauquelin compared to that of osmasome. It reddens vegetable blues, and thickens water, when dissolved in it. In alcohol it is insoluble. It does not crystallize, is neither precipitated by infusion of nutgalls, nor chlo- rine, land is not coloured blue by iodine, provided the lintseed from which it was procured was unadulterated. When this mucilage is put into water, it divides into two parts, the one soluble, the other insoluble. The insoluble portion, when treated with nitric acid, does not form mucic acid. It does not, therefore, belong to any of the genera of gum. But its nature has not yet been ascertained. The composition of mucilage from lintseed, according to the analysis of Guerin- Varry, is * Jour, de Pliarmacie, xix. 250. f According to Herberuer, it varies from 1 *aG86 to 1G31 1. Jour, de Pharmacie, XX. 411. X According to Hcrl)crger, it loses at 212° 19i per cent., but tlio gum is a litllo altered. Jour, de Pharmacie, xx. 410. 2x 674 OUMA. Soluble gum . Inaolul)lu Ashes Water' . 52-70 7'11 10-30 \ I : lOO'OO Tho ashes contain carbonates of potash 'and lime, phosphate of lime, chloride of potassium, sulphate of potash, oxide of iron, alu- mina, and silica. M. Guerin-Varry has subjected lintseed jiiucilago to an elemen- tary analysis, by means of oxide of copper, and obtained Carbon 34*30 Azote 7*27 Hydrogen . . . 5*()r> Oxygen . . . 52*78 100*00 As the soluble constituent is arabin, it is obvious, that the azote must come from the insoluble constituent, the nature of which has not been ascertained. These nunibcrs lead to 12 atoms carbon \ 1 atom a/ote 12 atoms hydrogen 14 atoms oxygen. Now, as arabin is composed of C'' H" O", it is obvious, that the insoluble matter of lintseed nucilage nmst consist of Az II O, pro- vided the analysis be correct. SECTION II. — OF BASSORIN. The substance called hnssorin was first noticed by Vauquelin, in a gum from Bassora. When this gum is treated with water, the bassorin remains in a gelatinous form.* It Mas afterwards found by Bucholz to constitute a portion of gum tragacanth,f and by John, of cherry-tree gum.J Its properties were first accurately investi- gated by M. Guerin-Varry. § To obtain bassorin, we have iothing more to do than to wash gum bassora with cold water, till every thing soluble has been taken up. The residue is then allowed to drain, dried upon a cloth, and finally freed from water, by placing it in a silver cup on a water-bath, till all the mixture is dissipated. It is polid, colourless, semitransparent, insipid, inodorous, and incrystallizable. It is tough, and, consequently, not easily reduced to powder. It is insoluble in water, whether cold or hot ; but swells up, and becomes like jell' . It is insoluble in alcohol ; and, like arabin, is incapable of u-jvlorgoing the vinous fermentation. 100 parts of it, when heated with 1000 parts of nitric acid, formed 22*61 parts of mucic acid, and at the same time some oxalic acid. * Ann. de Mus. d'Hist. Nat. xvi. 167. t Tasdienb. 1815, p. 61. X Schweigger's Jour. vi. 375. § Ann. de Cliim. ct de Pliys, xlix. 266. i 1 iiASSoniN. 675 yVhon treAtr-d with «\ilj)hui-ic nciil, it forms n cryHtnlllzalilo 8u<;ar, which, mroriliiijf to the I'xnoriiiu'iitH of M. (iiiorin- Vurry, is iiii'u- pablo of b»«ing made to undorjjfo tlie vinous formciitatioii. The constitucntH of liussonii, as iletormiiied by tho analysis of M. Guerin-Vjirry, aro Carbon 37'*28 or 10 atoms = 7*5 or per cent. 37*74 Hytlroi.: on (J'Ha or 1 1 atoms = 1'373 -— — (i'Ul Oxygen 55-87 or 11 atoms = 11 '00 — -_ 5.'5-35 lOO'OO l<>-875 100-00 It will now bo proper to notice tho principal gums which contain bassorin. 1. Gum liassora. Its specific f^ravity is I •359. Its colour is yellowish-white. It is imported into France ; but I am not aware of its beinf^ employed in this country. Its constituents, according to the analysis of M. Gucrin- Varry, are Water 21-89 Ashes 5-GO Arabin 11-20 Bassorin . . . . (J I -31 100-00 It yields to alcohol chlorophyllin, wax, acetate of potash, chloride of calcium, and bimalate of lime. 2. Gum tragacanth. This gum is the produce of the astragalus tragncantha, a thorny shrub, which grows in Candia, and other islands of the Levant.* The gum is said to exude about the end of June from the stem and larger branches, and soon dries in the sun. It is in the state of hard vermiform pieces, of a white colour, and not nearly so transparent as gum arable. Its specific gravity is 1-384. When heated to a temperature between 104° and 122-^, it becomes more easily pulverizable. When put into water it gra- dually swells, and forms a thick mucilage. When this mucilage is left to itself for some weeks, it gives out a smell similar to that of starch placed in the same circumstances, and to that of butyric acid. The insoluble portion of this gum becomes blue by iodine, and therefore contains starch. The constituents of gum tragacanth, according to the analysis of M. Guerin- Varry, are ♦ According to Sieber, gum tragacanth is not brought from Crete, but from Asia Minor, and chiefly from Mount Ida. The plant which yields it is the astragalus vents. It grows between 2300 and 3000 feet up the mountain. It is from Smyrna that it is imported into Europe. There is obviously some confusion in this statement. Ida is a mountain in Candia. Tournefort gives a description of the plant which yields tragacanth un- der the name of limoniiim creticutn, and assures us that he witnessed the gum tragacanth exuding from it spontaneously. See Tournefort's Voyage, i. 58. — English translation. * '( !| Ml' il lyii C7(i GUMS. , '.'il ;F Water Ashes Arabin Bassorin and starch l.y 53-3 33-1 100-0 3. Gum kuteera. This gum, according to Dr Roxburgh, is the protjuce of the sterculio urens* a tree which grows in Hindostan. Having some resemblance to gum tragacanth, great quantities of it were imported into Great Britain, about the beginning of the pre- sent century, for the use of the calico-printers, but it was found not to answer as a substitute for gum Senegal. Gum kuteera is in loose wrinkled drops or pieces, without smell or taste, and mostly transparent. In water it slowly forms a pulp or jelly, like gum tragacanth ; but if pourded well in a mortar, and then boiled in water for 15 minutes, with constant agitation, it is said to be com- pletely dissolved. A tea spoonful of its powder gives to water the consistence of capillaire. In India it enters into the composition of some varnishes ; it is used by the calico-printers, and is one of the ingredients of a famous medicine for horses among them.t Some years ago I received from a calico-printer of Glasgow a specimen of a gum, which he found in considerable quantity in a calico-printing establishment, which he had purchased in the neigh- bourhood of Perth. It was in large brown-coloured and wrinkled translucent pieces, having a certain degree of softness ; so that they could not be pounded in a mortar. When put into water, they did not dissolve ; but gradually imbibed the water, and swelled out into a jelly, so nearly colourless, that its presence at the bottom of the vessel containing water was not perceptible, till the water was agi- tated by moving the vessel. When boiled for some hours with water, this jelly completely dissolved. But the water was not mu- cilaginous, like a solution of gum arable, nor had it the least adhe- sive property. When two pieces of paper, besmeared with this solution, were laid upon each other, and allowed to dry, they did not cohere together, but separ.ated just as if the pieces of paper had been moistened by pure water. Thus this substance, though re- sembling gum in its appearance, possessed none of the properties of that substance, and could not be employed to thicken acids or colours intended to be printed on the cloth. I do not know how far this substance agrees with bassorin ; and not being acquainted with the plant from which it was obtained, though there is reason to suspect that it came from India, I can give no farther account of it. I mention it merely to make any per- son, who may be going to India, and is possessed of chemical knowledge, aware of the circumstance. Becauso this peculiar sub- stance, if it could be discovered again, is highly worthy of investi- gation. • Kicholsoii's Jour, xxvii. 70. \ Cowie ; Nichohon's Jour. vii. 301. CERASIN. SECTION 111. — OF CERASIN. fi77 This name has been given to a substance in cherry-tree gum which remains undissolved when that gum is treated with cold water. When obtained by this process, and dried, it possesses the following properties : — It is solid, tasteless, semitransparent, insipid, inodorous, incrys- tallizable, and easily pulverized. It is insoluble in alcohol. Does not undergo the vinous fermenta- tion. Swells a little in cold water, but does not dissolve. When boiled in water, it is converted into arabin. It is isomeric with arabin, as might be expected from its easy conversion. Probably arabin was originally in the same state with cerasin, but rendered soluble in cold water by the great heat to which it is exposed, or in which it is produced. The composition of cerasin was found by M. Guerin-Varry as follows : — Water " 8-4 Ashes ..... I-O Cerasin ..... 90-6 100^0 15-43 grains of it being boiled for six hours in 122 cubic inches of water, adding water as it evaporated, was completely dissolved. Being evaporated to dryness in a platinum capsule, and analyzed, it was found composed of Water 8-402 Ashes 1-011 Arabin .... 90-587 100-000 Numbers almost coinciding with the former, arabin being substi- tuted for cerasin. The gum given out by the cherry-tree, apricot, plum, peach, and almond, consists of a mixture of arabin and cerasin. The following table exhibits the specific gravity of these gums, as determined by M. Guerin-Varry: — Cherry-tree gum . . . 1'475 Apricot . Plum Peach Almond 1-469 1-491 1-421 1-530 The following table exhibits the composition of these gums, as analyzed by the same chemist : — Water Ashes Arabin Cerasin Cherry-tree. Apricot, Plum. Peach, 14-21 3-19 Almoiid, 13-79 2-97 12 1 6-82 3-33 15-15 2-62 52-17 34-9i 89-85 82-83 82-60 83-24 100 100 100 100 100 678 GUMS. The following table exhibits the quantity of raucic and oxalic acid furnished by 100 parts of these gums, when treated with 400 parts of nitric acid : — Cherry-tree gum . . . 15'74 Apricot . . . . . 15*97 Plum 15-78 Peach 14-99 Almond 15-03 SECTION IV. OF CALENDULIN. Calendulin was obtained by Geiger from the flowers of the Calen- dula officinalis, or Marygold* The process which he employed was the following : — The flowers and leaves of marygold were digested in alcohol, and the solution was evaporated to the consistence of an extract. This extract was digested, first in ether, which dissolved a substance analogous to wax ; it was then digested in water. There remains a mucilaginous substance, almost insoluble in water, whether boil- ing or cold. This is the calendulin. When dried it is yellowish, translucent, and brittle. When moistened with water it swells up, and is again converted into mucilage. In the impure state in which it exists in the plant, it is soluble in hot water, but during the cool- ing the liquid assumes the form of a jelly. Calendulin is insoluble in the dilute acids, but it dissolves in con- centrated acetic acid. Dilute solutions of the caustic alkalies dis- solve it; but it is insoluble in the alkaline carbonates, and in lime water. It dissolves easily in strong and absolute alcohol ; from the former, it is deposited in the form of a jelly ; and from the latter, in dry pellicles. Infusion of nutgalls does not precipitate it. It is insoluble in ether, and in the fixed and volatile oils. SECTION v. — OF SAPONIN. This substance was discovered in 1832, by M. Bussy,t while examining a root sent him by the Societe d' Encouragement, which it seems was capable of being employed as a substitute for ooap. The root was considered to belong to the Gypsophiia struthium, a plant which grows spontaneously in Hungary, Greece, and several countries of the east. Bucholz had already, in 1811, described a substance from the saponaria officinalis, to which he gave the name of saponin.X And this substance had been further examined by Braconnot.§ Bussy applied the same name to the substance ex- tracted from the root of the Gypsophiia struthium, doubtless because he conceived it to be the same with the saponin of Bucholz and Braconnot. Saponin may be obtained from the root of saponaria officinalis, or oi gypsophiia struthium, by the following process: — * Bisser. do Calendula officinali. Heidelbcrj,', 1819. f Jour, de Pharmacie, xix. 1. % Taschenbuch, 1811, p. 33. $ Jour, do Pliys. Ixxxiv. 287. SAPONIN. 679 The root, previously reduced to powder, is boiled for a few minutes with alcohol of the specific gravity U"837. The solution being filtered and left to cool, deposits the saponin, which is pressed between folds of blotting paper and dried. It is a white friable mass, without any appearance of crystalliza- tion. Its taste is very acrid, and it continues long in the mouth. When in powder it acts as a powerful sternutatory. In water it dissolves in all proportions like gum. The aqueous solution froths, when agitated, like a solution of soap ; and 1 part of saponin is capable of communicating this property to 1000 parts of water. Weak alcohol is a good solvent of saponin, and the solubility diminishes as the strength of the liquid increases. But saponin is still soluble in alcohol of the specific gravity 0*817. Ether has no action on saponin ; but if the root has not been digested in ether before the alcoholic decoction is made, the etli m* dissolves a portion of fatty matter with which the saponin in that case is mixed. When saponin is heated in a retort or glass tube it swells up and blackens, without being volatilized, but gives out a considerable quantity of acid erapyreumatic oil. In the air it burns with flame, swelling up at the same time. Dilute acids, when added to a solution of saponin, occasion no sensi- ble change. Muriatic and acetic acids augment its solubility in alcohol. When 3 parts of saponin are digested with 5 parts of nitric acid of the specific gravity 1-33, it is partly coagulated like an aqueous solution of albumen. After this the action of the acid becomes rather violent, the matter swells up, and a yellow matter, having a resinous appearance, swims upon the surface. This matter is friable, slightly bitter, soluble in alcohol ; and when the alcoholic solution is evapo- rated, crystals are deposited. This substance is an acid, and appears to have considerable analogy to carbazotic acid. Alkalies have no action on saponin. Barytes water poured into a solution of 1 part of saponin in 4 parts of water, occasions a white preci- pitate, soluble in water, and in an excess of the solution of saponin. Neither lime water nor acetate of lead occasion any precipitate. But diacetate of lead occasions a copious precipitate. According to the analysis of Bussy, saponin is composed of Carbon 51*0 or 26 atoms = 19*5 or per cent. 50*82 Hydrogen 7*4 or 23 atoms = 2*875 — — 7*49 Oxygen 41*6 or 16 atoms =16*0 — — 41*69 1000 38*375* 100 M. Bussy poured subacetate of lead into a solution of saponin. When he stopped the addition, as soon as a precipitate ceased to fall, the compound formed consisted of • \ sliort account of saponin has been given in page 51 of this Volume. There is a typographical error in that place, 79 "373 being substituted for 38"373, the true number. Wo iiave added the observations that follow, as calculated to throw some light on the true atomic weight of saponin. 680 GLUTINOUS SUBSTANCES. Saponin Oxide of lead 72-8 or 37-43 27-2 or 14 1000 When he added an excess of subacetate of lead, the compound formed was composed of Saponin . . . 61*6 or 22-45 Oxide of lead . . 38*4 or 14 100-0 The first of these compounds gives 37-43 for the atomic weight of saponin, which approaches the preceding formula. The second, unless it be a disalt, would lead to the formula 15 atoms carbon = ir25 or per cent. 51*43 13 atoms hydrogen = 1-G25 — — 7*43 9 atoms oxygen = 900 — — 41-14 21-875 100-00 This formula would make the atomic weight 21-875, which comes pretty near 22-45, the number resulting from the second compound of saponin and oxide of lead. I am disposed to prefer the first formula. CHAPTER VII. OF GLUTINOUS SUBSTANCES. If wheat flour be knepded into a paste with a little water, it forms a tenacious, elastic, soft, ductile mass. This is to be washed cau- tiously, by kneading it under a small jet of water till the water no longer carries oft" any thing, but runs oft' colourless ; what remains behind is called gluten. It was discovered in 1742 by Beccaria, an Italian philosopher, to whom we are indebted for the first analysis of wheat flour.* Gluten, when thus obtained, is of a grey colour, exceedingly tenacious, ductile, and elastic, and may be extended to twenty times its original len;:fth. When very thin, it is of a whitish colour, and has a good deal of resemblance to animal tendon or membrane. In this state it adheres very tenaciously to other bodies, and has been often used to cement together broken pieces of porcelain. Its smell is peculiar. It has scarcely any taste, and does not lose its tenacity in the mouth. In the air it assumes a brown colour, and becomes as it were covered with a coat of oil. When exposed to the air, it gradually dries ; and when completely * Colloct. Acadctn. xiv. I. oinpou nd e atomic ila. The dch comes compound !r the first er, it forms fashed cau- he water no hat remains Beccaria, an irst analysis exceedingly twenty times colour, and iibrane. In nd has been n. Its smell 3 its tenacity and becomes ;n completely ALBUMEN. 681 dry, it is pretty hard, brittle, slightly transparent, of a dark brown colour, and has some resemblance to glue. It breaks like a piece of glass, and the edges of the fracture resemble in smoothness those of broken glass ; that is to say, it breaks with a vitreous fracture. Fresh gluten imbibes water, and retains a certain quantity of it with great obstinacy. To this water it owes its elasticity and tena- city. When boiled in water it loses both these properties. When kept moist, it very soon begins to decompose, and to undergo a species of fermentation. It swells, and emits air-bubbles, which Proust has ascertained to consist of hydrogen and carbonic acid gases.* It emits also a very offensive odour, similar to what is emitted by putrefying animal bodies. Cadet kept gluten in a vessel for a week in a damp room. Its surface became covered with byssi, the fermentation just mentioned had commenced, and the odour was distinctly acid. In 24 days, on removing the upper crust, the gluten was found converted into a kind of paste, of a greyish white colour, not unlike bird-lime. In that state he gave it the name of fermented ghilen.^ If the gluten be still left to itself, it gradually acquires the smell and the taste of cheese. This curious fact was first ascertained by Rouelle, junior. In that state it is full of holes, and contains the very same juices which distinguish some kinds of cheese. Proust ascertained that it contains ammonia and vinegar ; bodies which Vauquelin detected in cheese : and ammonia robs both equally of their smell and flavour.! Gluten has been resolved by modern chemists into four distinct principles ; namely, albumen, emulsin, mucin, and glulin. These will constitute the subject of the four following Sections. SECTION I. — OF ALBUMEN. When fresh gluten of wheat is digested in hot alcohol till every thing soluble is taken up, a bulky substance of a greyish colour remains, which constitutes what has been called vegetable albumen. When thus obtained, it possesses the following properties : — 1. Soluble in water. But when the solution is heated, the albu- men coagulates and becomes insoluble. 2. It is insoluble in alcohol and ether. 3. It has not the property of cementing pieces of paper or cloth together, as is the case with a solution of gum, or of starch. 4. When dry, it is opaque, and has a white, grey, brown, or even a black colour, according to circumstances. 5. It is readily soluble in caustic alkalies. The solution may be rendered slightly acid without any precipitation taking place. But a great excess of acid throws down a precipitate, which is a compound of albumen and the acid employed. This precipitate is but little soluble in water ; and when dissolved in that liquid, it is precipitated again by acids, prussiate of potash, corrosive sublimate, and infusion of nutgalls. • Jour, de Pliys. Ivi. 103. f Ann. do Cliim. xli. 315. X Proust, Jour, de Pliys. Ivi. 100. I ■I V^ i t'. ' -! II' if' ; f h is G82 GLUTINOUS SUBSTANCES. i 6. It is not dissolved by the alkaline carbonates, and after having been coagulated, it does not dissolve even in caustic ammonia. If we add carbonate of ammonia to a saturated solution of albumen in caustic potash, a portion of the albumen precipitates, but is again redissolved by adding a sufficient quantity of water. Carbonate of ammonia is the best precipitant of albumen from an acid solution. The albumen falls down in white flocks. Caustic ammonia throws down nothing from such a solution. 7. When earthy or metalline salts are mixed with a solution of albumen in caustic potash, the albumen combines with the base of the salt, and generally forms with it an insoluble compound which precipitates. When a persalt of iron is employed as a reagent in this way, the precipitate, after being washed and dried, has a deep red colour. The protosalts of iron throw down a white precipitate, which becomes yellow by exposure to the air, and the salts of copper throw down a pale bluish-green precipitate. SECTION II. OF EMULSIN. This name has been given by Wiihler and Liebig to a peculiar substance which exists in almonds, and which has the curious pro- perty of decomposing amygdalin, and of forming hydrocyanic acid, and volatile oil of bitter almonds. To form some notion of its properties, they digested almonds in ether till they were deprived of all their fixed oil. The residue dissolves almost completely in water, and gives a colourless, or slightly opalescent liquid. When heated to 158° it becomes muddy, and at 212° coagulates into a thick mass, having the aspect of starch mucilage. When amygdalin was added to the matter, no visible change took place, but a strong smell of hydrocyanic acid became perceptible ; though no oil was deposited. Yet on distilling the mixture, a considerable quantity of the essential oil was obtained, and the emulsin was deposited in white flocks. The solution of emulsin is precipitated by alcohol in thick white flocks. These flocks dissolve completely in water, even if they have been previously dried. And this solution produces the same eft'ect with amygdalin as a solution of emulsin newly prepared.* This constitutes a remarkable difference between emulsin and vegetable albumen. The investigation of emulsin was taken up by Mr Richardson, in the laboratory at Giessen, during the summer of 1837, and it was afterwards prosecuted by him in M. Pelouze's laboratory, in Paris, in the beginning of 1838. In these last experiments he was assisted by Dr R. D. Thomson of London. The milk of sweet almonds was mixed with four times its volume of ether. The mixture was well agitated, and then left at rest for some days. A clear liquid gradually separated, upon which the ether, pnd a quantity of insoluble matter floated. The clear aqueous liquor being drawn ofl', was mixed with pure alcohol. An abundant ' Ann. de Chim. et de Phys. Ixiv. 202. MUCIN. 683 chardson, in 18 or per cent. 48-81 2-875 7-79 7 — 18-99 9 — 24-41 white flocky precipitate fell, which was thoroughly washed, and then dried under tlie air pump, with sulphuric acid, for two or three weeks. In this state it was considered as pure uncoagulated emulsin. The coagulated emulsin was thrown down by boiling a portion of the aqueous solution of it. When emulsin was boiled in barytes water, ammonia was evolved, and the emulsin gradually dissolved. The solution was treated with carbonic acid, to throw down all the uncorabined barytes, and gently heated, to separate any bicarbonate of barytes that might have been formed. By evaporating the solution, a bitter tasted salt was obtained, which cou t.ined a large quantity of barytes. To the acid of this salt the name of emulsic acid has been given. Its characters and atomic weight have not yet been determined. These facts render it exceedingly probable thjit emulsin is an amide of emulsic acid. Mr Richardson made two analyses of it in Professor Liebig's laboratory, the mean of which gave Carbon 48-835 or 24 atoms = Hydrogen 7-732 or 23 atoms = Azote 18-911 or 4 atoms = Oxygen 24-722 or 9 atoms = 36-875 100 This formula can exhibit only the ratios betveen the atoms of each constituent. To know the true composition, it world be necessary to be acquainted with the atomic weight of emulsic acid. Were we to consider emulsic acid as C'^* H'^' Az^ O"*, the constitution of emulsin might be represented thus, C^* H'^' Az' O'-* + Az H^; and the addition of an atom of water would convert it into an atom of emulsate of ammonia. SECTION III. OF MUCIN. If we digest, or rather boil, alcohol upon the gluten of wheat, and filter the liquid while hot, it deposits on cooling a quantity of mucin. This substance possesses the following characters : — 1 . It dries into transparent grains. 2. It burns like animal matter. 3. It is more soluble in water than glu<-' ".. And according to the analysis of Saussure, it constitutes about 4 per cent, of the gluten of wheat flour. 4. One hundred parts of hot water dissolve 4 parts of mucin. The solution runs very rapidly into putrefaction. Mucin is insolu- ble in ether. 5. The aqueous solution of mucin is precipitated by infusion of nutgalls, slightly by alcohol, and not at all by ammonia, lime water, acetate, or diacetate of lead, corrosive sublimate, or prussiate of potash. 6. When mixed with i^tarch and made into a paste, and kept for 10 hours in a temperature of 145°, it converts the starch into sugar \' i! : i i '15 « i :, \m pi 084 GLUTINOUS SUBSTANCES. and dextrine. Saussure's experiments were made upon the follow- ing proportions, with the following results : — 2 starch and 1 albumen formed 2 dextrine, with a trace of sugar. 2 starch and 1 gluten formed C dextrine, and 1-75 sugar. 2 starch and 1 mucin formed 22 sugar, and 15 dextrine. SECTION IV. — OF GLUTIN. This name has been given by M.dc Saussure to the substance which had been already described by Einhott", under the name of kleber. It may be obtained by boiling alcohol upon the gluten of wheat, and freeing the solution from mucin, by repeated precipitations. We obtain at last a transparent colourless solution. If the alcohol be evaporated, the glutin is left in tiie state of a yellowish translucent matter, which possesses the following properties : — 1. It is almost insoluble in water. 2. It is soluble in alcohol, both cold and hot. 3. It is soluble in dilute acids, especially the acetic. 4. It is soluble in caustic alkaline leys. 5. The acid solutions are precipitated by prussiate of potash — the inner surface of the glass vessel containing the solution being covered with a semitransparent coating. 6. It is precipitated by the infusion of nutgalls, and the preci- pitate is not redissolved by ebullition. Glutin has been analyzed by Boussingault, who obtained Carbon 53-75 or 8^ atoms = 6-375 Hydrogen 7-55 or 7 atoms = 0-875 Azote 14-50 or 1 atom = 1*750 Oxygen 24-20 or 3 atoms = 3*000 100* 12-000 Einhoff has shown that glutin exists also in rye and barley, though it is not easily obtained from them in a separate state. M. de Saussure made some experiments in order to determine the alterations which wheat undergoes by germination. The following table exhibits the {»roportion of the several constituents, separated by analysis from 100 parts of wheat, before and after germination : — Starch Gluten Glutinous dextrine Glutinous sugar Albumen Bran Carbonic acid . * Ann. ilc Cliim. cl tic Pbvs. Ixiii. 229. Wheat. Di>. after gcniiiiintiuii. Do. after (i months' iti'cping. 72-72 11-75 3-46 2 44 1-43 5-50 97-30 65-80 7-64 7-91 5-07 2-67 5-60 61-81 0-81 1-93 10-79 8-14 4-07 3-38 94-69 90-93 /EIN. 685 The thiru column exhibits the constituents of wheat that had been kept for six months under water, at a temperature between 7 2° '5, and 83°'75, and afterwards dried.* No accurate experiments determine the constituents of the four substances described in the preceding Sections have yet been made, with the exception of the analysis of glutin by Boussingault. M. Marcet subjected the gluten of wheat to an ultimate analysis, and obtained Carbon 55*7 Hydrogen .... 7*8 Azote . . . . . 14-5 Oxygen 22-0 lOO'Of And he says that the albumen of wheat yields the very same con- stituents in the same proportions. These numbers lead to the following atomic constitution : — 9 atoms carbon = 6*75 or per cent. 5()*55 7^ atoms hydrogen = 0-9375 — — 7-85 1 atom azote =1*75 — — 14* 65 2i atoms oxygen = 2*50 — — 20*95 11-9375 100 But as gluten of wheat is never free from starch, and as it is un- likely that the constitution of the albumen, mucin, and glutin should be exactly the same, little confidence can be put in Mr Marcet's analysis. SECTION V. — OF ZEIN. The name zein has been given, by Professor Gorham4 to the gluten of zea mais, or Indian corn. It may he obtained by the following process :— Treat the meal of mais with water, in the same way as wheat flour is treated to obtain the gluten of Beccaria. There will remain in the li len bag, in which the meal was washed, a matter insoluble in wate' . Digest this matter in alcohol ; mix the alcoholic ;jolutiori with water, and distil off the alcohol. We obtain in this way a yellow, soft, flexible body, mixed with water. It possesses much vis- cosity and ductility ; but has neither taste nor smell. But water, most acids, and alkalies have little action on it. Gorham assures us that it differs essentially from the gluten of wheat, by containing no azote; and that it yields no ammonia when distilled. But Bizio affirms that he obtained ammonia by distilling the zein. Its specific gravity, as determined by Bizio, is 1-0347. It swells up in cold alcohol, and when the liquid is boiled, a slimy solution takes place. Ether placed in contact with it acquires a fine yellow * Memoires de la Societo Physique et d'Histoire Naturelle de Geneve, vi. 237. f Ibid. iii. 217. X Jo"""- oi' Science, xi. 203. CM fJLDTINOlJS 8U1JSTANCKS. colour ; but it does not disaolvo it completely. Acetic acid dis- solves it by the assistance of heat. Nitric acid converts it into a butyraccous mass, with the evolution of nitrous «jas. This matter mixes with oils, and may be aj^ain separated by alcoiiol, in which it dissolves readily, and from which it may be obtained unaltered by evaporating the solution. Zein dissolves in concentrated sulphuric acid. The solution has a purplish-red colour, and is jiflutinous. Zein does not dissolve in muriatic acid, even at a boiling tempera- ture. SECTION VI. — OF VISCIN. The characters of the substance called viscin, by Macaire, were first given by Vauquelin in 1799. It had collected on the epider- mis of a species of acacia, brought to Euro|)C by M. Micaut, and which Cels distinguished by the name of Robinia Viscosa* Within these few years the same substance was observed exuding spontaneously from the involucrum of the Atrnctylis gummifera. He a second time determined its properties, gave it the name of viscin, and subjected it to a chemical analysis.f But it was shown, in 1806, by M. Bouillon-Lagrange, that viscin is essentially the same with hird-lime.X Now, bird-lime was known to the ancients, being called i^m; by the Greeks, and visctim by tiie Romans. Pliny informs us that it was made from acini (probably it y berries), and he describes the process of the manufacture, and mentions the uses to which bird-lime was put.§ Viscin, when fresh, is soft and elastic, and has a greenish or brownish colour. It adheres firmly to the fingers, or to almost any body with which it comes in contact. It is insoluble in water and fixed oils, slightly soluble in alcohol, and very soluble in ether and oil of turpentine. When heated it softens, melts, and swells, and becomes slightly yellow ; when cooled it remains liquid, and attaches itself to the fingers like glue. It burns with a white flame, first becoming soft, and then melting. During its combustion it gives out much smoke, with the smell of empyreumatic oil. When distilled it gives off" an acid, but no am- monia, showing that it contains no .azote. It is soluble in caustic potash, which becomes slightly coloured. Sulphuric acid dissolves it, assuming a deep brown colour. No artificial tannin is formed, but a great deal of charcoal is deposited. Nitric acid dissolves it by the assistance of heat. The solution is reddieh-yellow. When evaporated to dryness a yellowish-white sub- stance remains, not bitter, and containing no oxalic acid, but soluble in caustic potash, and burning like tinder. Its constituents, as determined by the analysis of M. Macaire, are * Ann. de Chim. xxviii. 233. f Mcmoires de la Socictc Pliysique ct d'Histoire NaiurcUe do Gcnrvc, vi. 27. J Ann. de Chiin. Ivi. 24. $ C. Plinii Secundi Hist. Mundi, lib. xvi. c. 44. VISCIN. 087 Carbon 75*0 or 13 atoms = l)'7r) Hydrogen 9*2 or 10 ntoms = 1*25 Oyxgcn] 15*2 or 2 atoms = 2*00 or per cent. 75*0 — -- 9-<) — — 15-4 lOO'O* 13 100-0 But these proportions arc so different from what have heen found in other vegetahle substances, that they must he confirmed hy very careful experiments before wo can rely upon them. There can be little doubt that the viscid substance which covers the stem of the lychnis viscaria, saxifrana tridactylites, and a few other plants common in this country, is viscin ; though, so far as I know, it has not yet been subjected to a chemical examination. Artificial bird-lime is prepared from different substances in dif- ferent countries. The berries of the misletoe are said to have been formerly employed. They were pounded, boiled in hot water, and the hot water ])oured off. At present bird-lime is usually prepared from the middle bark of the holly. The process followed in Eng- land, as described by Geoffrey, is as follows : — The bark is boiled in water seven or eight hours, till it becomes soft. It is then laid in quantities in the earth, covered with stones, and left to ferment or rot for a fortnight or th''ee weeks. By this fer. 'cntation, it changes to a mucilaginous consistency. It is then taken from the pits, jiounded in mortars to a paste, and well washed with river water. Bouillon- Lagrange informs us, that at Nogent le Rotrou, bird-lime is made by cutting the middle bark of the holly into small pieces, fermenting them in a cool place for a fortnight, and then boiling them in water, which is afterwards evaporated. At Com- merci various other plants are used.f Bouillon-Lagrange made bird-lime, for the purpose of analysis, by the following process : — He bruised a sufficient quantity of the middle bark of the holly, boiled it in water for four or five hours, and then deposited it in pits placed in earthen pans, where it con- tinued, being moistened occasionally with water, till it became vis- cous. Lastly, it was freed from all heterogeneous substances, by washing it with pure water. Thus prepared, it resembled the bird-lime of Commerci very cx.actly.J Its colour is greenish, its flavour sour, and its consistence gluey, stringy, and tenacious. Its smell is similar to that of lintseed oil. When spread on a glass plate, and exposed to the air and light, it dries, becomes brown, loses its viscidity, and may be reduced to powder ; but when water is added to it, the glutinous property re- turns. It reddens vegetable blues. When gently heated it melts and swells, and emits an odour like that of animal oils. When heated on red-hot coals, it burns with a lively flame, and gives out a great deal of smoke, leaving a white ash composed of carbonate of lime, alumina, iron, sulphate, and muriate of potash. • Jour, de Pharmacie, xx. 18. \ Nicholson's Jour. xiii. 145. X Bouillon-Lagrange, Nicholson's Jour. xiii. 143. (i 'I I ' f>8H nra'TiNoiis suhhtancms. I \l i:, : ,.1 ''»' I : Wiitcr lias little action on hinl-rmic. VVIicii hoilcd in wntur, the hird-liino becomes more rK|ui(l, Imt recovi'rs its orijjiiial properties when the water cools. The water, !)} this treatim'iit, a((|nire8 the proi)ert) of redileuin;^ vejfetahle hliies, and when evaporated, leaves umuoilaii of the jtiuHH (ihirit, pinits si/lirstris, li/roptHliutn clnvatum, and supposed by hiui to eonytitute the characteristic cun- rttituent of every speciivs solution of potash or soda. Hy this treat- ment, some sugar, extractive, and oil are reujoved, and 100 parts of lycopodium leave about 89"5 parts of pollenin. It preserves the yellow colour, the pulverulent form, and the great cond)ustil)ility of lycopodiinn. It is insoluble in water, alcohol, ether, fat and volatile oils, and likewise in naphtha. If it be left moist in a humid situation, it soon putrefies, giving out a disagreeable odour, mixed with that of aumionia, and at last acquires exactly the smell of putrid cheese. Nitric acid acts on it as on gluten, converting it into oxalhydric and oxalic acid, bitter matter, and tallow. According to Foureroy and Vauquelin, the pollenin extracted from the date-tree dissolves slightly in muriatic acid, and the solu- tion, which has a greenish-yellow colour, gives a precipitate of yel- low pulverulent \>olleuni, when an alkali is poured into it.t Braconnot examined the pollenin of the tj/pha latifolia, and found its properties somewhat different. When freed by means of water, alcohol and ether, of every thing soluble in thes(> liquids, its pro- perties were the following : — When distilled it gave much less am- monia than vegetable albumen does. Concentrated sulphuric, muriatic, and acetic acids dissolve it without deconiuosition. Water throws it down from these solutions. The j)recipitate thus obtained is soluble in potash and ammonia, and the acids ii: their turn throw down the pollenin from the alkaline solutions. When the alkaline solutions are boiiod, the pollenin is altered, for it is no longer pre- cipitated by acids, though it is still capable of being thrown down by alcohol and infusion of nutgalls.J M. Macaire-Princep has examined the pollenin of the cedar. It is yellow, pulverulent, without taste or smell, and burns with less vivacity than the pollen of lycopodium. Besides pollenin, it contains resin, gum, sugar, and different salts, as, for example, malate and * Gelileii's Jour. vi. 39D. f Aiiuules du Miis. d'Hist. Nut i.4l7. \ Ann. de Chiin. et de Pliya. xlii. Ul, •2 Y 'I ••--^aKSBWnWMW^.^^^, F' ' 690 GLUTINOUS SUBSTANCES. Il-I ! ( sulphate of potash, phosphate of lime, and a little silica. He com- pares this poUenin with starch, and says that it is a mistake to sup- pose that poUenin contains azote. The poUenin of the cedar is composed, according to his analysis, of Carbon 40*0 or 1 1 atoms = 8*25 or per cent. 39*76 Hydrogen 11-7 or 20 atoms = 2-50 — — 12-05 Oxygen 48-3 or 10 atoms = 10-00 — — 48-19 100 20-75 100-00 The poUenin of lycopodium he found composed of Carbon 50-2 or 17 atoms = 12-75 or per cent. 51-12 Hydrogen 8-6 or lU atoms = 2-1P75 — — 8-79 Oxygen 392 or lO" atoms = 10-00 — — 40-09 98-0 24-9375 100-00 But these results being inconsistent with the previous observations of Vauquelin, Bucholz, and Braconnot, who observed the evolution of ammonia when poUenin was distilled, and therefore inferred the existence of azote as an essential constituent, would require to be repeated with much care, before they could be adopted. M. Fritche has shown, by microscopical observations, that poUenin is in fact a complex organized body.* It is obvious from this, that it cannot with propriety be considered as an immediate vegetable principle. SECTION VIII. — OF LEGUiMlN. The fleshy cotyledons of the seeds of all papilionaceous plants contain according lo the experiments of Braconnot, a peculiar prin- ciple, to which he has given the name of legumin.f The investiga- tion of these seeds was begun many years ago by EinhofF, who published an elaborate analysis of peas, beans, and kidney beans in 1805.$ From peas Einhoff obtained a peculiar substance, to which he gave the name of animo-vegetable principle, CkWd the properties of which he described. Braconnot's mode of obtaining legumin from peas was as follows : — Ripe peas were macerated several days in warm water to render them soft, and cause them to swell. They wore then reduced to a pulp in a marble mortar, mixed with pure water, and after being agitated, the whole was thrown upon a seirce. A milky liquid passed through, which being left for some time in a state of rest de- posited the starch which it held in suspension. The muddy liquid re- maining contains the legumin in solution, seemingly combined with a vegetable acid, and this matter gives it the property of frothing when agitated, like white of an egg when beat up with water. Yet it does not appear to contain any albumen, for when it is heated no flocky deposit takes place. But if we evaporate it, the legumin is deposited by little and little, under the form of diaphanous pellicles, having a * PoggendorPs Annalen, xxxii. 481. f Ann. de Chini. ct de Phys. xxxiv. 69. % Gehlen's Jour. vi. 115, 136, and 542. LEGUMIX. 691 mucilaginous appearance, and this deposition continues till the end of the evaporations. Legumin thus obtained is still impure and has a greenish colour. If it be washed, while still moist, with boiling alcohol, the impurities are dissolved, and the legumin remains in a state of purity. Thus obtained it has a fine white colour, and does not alter the colour of litmus paper. When dried it is semitransparent, and still retains its white colour. It is soluble in water, but insoluble in alcohol. Oxalic, malic, citric and other vegetable acids, even when diluted with a ^ceai deal of water, dissolve it with great readiness. The mineral acids on the contrary, precipitate it from its solutions, because it forms with them acidulous compounds, which are very little soluble. When the liquid is heated, these precipitates dis- appear, but on cooling, the whole is converted into a gelatinous mass, like pitch, which becomes again liquid when heated. When heated with a little of any vegetable acid, tartaric acid, for example, it forms a thick mucilaginous liquid, which when diluted with water has scarcely any acid taste. Infusion of nutgalls throws down a copious white precipitate, which, when heated, contracts, and becomes buiF-colcured. When legumin is long boiled with concen- trated sulphuric acid, it is decomposed and produces the same sub- stances as animal muscle does when treated in the same way. With nitric acid it behaves like vegetable albumen. Its solution in a vegetable acid is not precipitated by alcohol. Alkaline hydrates and carbonates, even when very dilute, dissolve it with facility. It is soluble likewise in barytes and lime water, and the solutions froth like aqueous solutions of soap. When either of these two solutions is boiled, a coagulum is formed, and when an acid is added which forms an insoluble or little soluble salt with the lime or barytes (such as carbonic, sulphuric or phosphoric acid), there immediately precipitates a combination of legumin with the earthy salt. With iodine it forms a soluble compound without the assistance of heat. But if we heat the liquid, a reddish-yellow precipitate falls, which preserves its colour after being dried. This precipitate is insoluble in water and alcohol, but dissolves readily in ammonia. The solution is colourless, but is precipitated yellow by acids. Starch gives a blue colour to this precipitate, and when it is heated above 212°, the iodine which it contains is volatilized, and the legumin remains behind. Braconnot considers legumin as possessed of alkaline properties. It is in his opinion intermediate between gluten and vegetable albumen; differing from the former in being insoluble in alcohol, and from the latter in dissolving with facility in alkaline carbon- ates. ■;«■» iii 15, 136, and 542. SECTION IX. — OF AMYGDALIN. This name has been given by Dobereiner to a substance which exists in the bitter almond, though the sweet almond seems desti- 692 tJLUTINOUS SUBSTANCES. ' ;!, tute of it. Its properties were examined in detail by Robiquet and Boutron-Charlard.* And it was examined and analyzed by Wiililer and Liebig.t The best mode of obtaininjT it, is to dijjcst the matter of bitter almonds, deprived of their oil, in ether, and afterwards in hot anhy- drous alcohol us long as there is any thing taken up. The first alcoholic decoction deposits on cooling a small (piantity of amygdalin but the subsequent one deposits nothing. Mix all the alcoholic liquids and distil oft' the alcohol till the licpiid is reduced to the con- sistence of a syrup. Put this syrup into a tall and narrow glass cylinder, and add 6 or 8 times its volume of ether, agitate well and leave the whole at rest. lu a few hours the liijuid divides itself into three layers ; the uppermost, consisting of the ether containing in solution a little resin, is limpid jind transparent ; the middle layer, containing the amygdalin, seems as if it contained chalk ; and the lowermost layer, containing an incrystallizabh; sugar, is limpid and amber-coloured. Remove by means of a syphon the uppermost and undermost layers. Dissolve the middle layer in boiling alcohol, and set the solution aside. The amygdalin is deposited in short white needles. Wiihler and Liebig found the following process to yield the greatest quantity of amygdalin : — The residue of bitter almonds, deprived of their fixed oil by expres- sion, was treated twice successively by alcohol of 0*8 157. The liquor was filtered through cloth, and the residue pressed out. On cooling the liquid becomes muddy and deposits a fixed oil which must be separated. It is then filtered in order to obtain it in a clear state. On being left for several days it deposits a quantity of amygdalin in crystals. Distil off the alcohol till the residue amounts only to ^th of its original bulk. Let it cool and mix it with its own bulk of ether. The whole amygdalin precipitates. Collect it and sub- ject it to pressure between folds of blotting paper, to get rid of a quantity of fixed oil with which it is mixed. Agitate it in ether to get rid of the last portions of this oil, then dissolve it in boiling alcohol. It crystallizes on cooling in white scales. They have more lately ascertained that if the liquid containing the amygdalin be mixed with yeast, and fermented to get rid of the sugar contained in it, then filtered, evaporated to the consistence of a syrup and mixed with alcohol, the amygdalin is precipitated in the state of a white powder.^ it has no smell. Its taste is at first sweet, then bitter, commu- nicating the impression of bitter almonds. It cannot be sublimed. When heated it swells and is decomposed, giving out first the odour of caromel, and afterwards of hawthorn. It is not altered by ex- posure to the air. We do not know whether it be soluble in water. It is scarcely soluble in cold alcohol unless it contains water, but boiling alcohol dissolves it easily, and it crystallizes as the solution * Ann. dc Cliim. et. de Pliys. xliv. 332, 37«. f Jl''iJ- '"'i'- >83. X Annaleii dcr Pharmacie, xxi^-. 45. GLAIIIIN. 698 'Kjuet and y Wiihler of bitter hot anliy- The first iunygtlalin alcoholic o the con- •row ghi8S e well and ides itself containing iddle layer, k ; and the linipiil and erniost and ng alcohol, ed in short yield the il by expres- The liquor On cooling ich must be 1 clear state. >f amygdalin lunts only to its own bulk t it and sub- get rid of a it in ether to it in boiling id containing ret rid of the consistence of ipitated in the itter, commu- ; be sublimed, drst the odour altered by ex- luble in water, .ins water, but xs the solution id.Uiii. \8ru cools. It is insoluble Jn ether. Dry chlorine has no notion on it ; but the moist gas cau3os it to swell and changes it into a white powder insoluble in alcohol and in water. Nitric acid decomposes it, and among other products benzoic acid is formed. Caustic potash dissolves it ; when the solution is boiled ammonia is disengaged, showing the presence of azote in amygdalin. The acids occasion no precipitate when added to the alkaline solution. The crystals of amygdalin, according to the experiments of Wiihler and Liebig, are composed of AmygdaUn .... 89*43 Water 10-57 This is obviously 1 atom amygdalin 6 atoms water 100 57 ()-75 63-75 It was analyzed by MM. Henry, junior, and Plisson, who obtained Carbon 58-50 IG or 38 atoms = 28-50 or per cent. 58-GI Hydrogen Azote Oxygen 7-0857 or 27 atoms = 3-375 — ~ 3-0288 or 1 atom = 1-75 — 30-7238 or 15 atoms = 15-00 — 6-94 3-60 30-85 99-9999* 48-625 100-00 Rut it has been more lately analyzed with more accuracy by Wiihler and Liebig, who obtained Carbon 52-00 or 40 atoms = 30 or per cent. 62-62 Hydrogen 6-06 or 26 atoms = 3-25 — — 6-70 Azote 3-069 or 1 atom =1-75 — — 3-07 Oxygen 38-871 or 22 atoms = 22 — — 38-61 lOO-OOOt 57 100 Comparing these numbers with the constitution of the crystals of amvirdalin, it is obvious that its atomic weight is 57. When amygdalin comes in contact with a substance in almonds, similar in its appearance to vegetable albumen, and which Wiihler and Lie])ig term emulsin, a decomposition immediately takes place, and hydrocyanic acid and oil of bitter almonds are immediately formed. SECTION X OF GLAIIIIN. This name has been given to a peculiar substance which has been observed in the sulphureous mineral waters of the Pyrenees, par- ticularly in those of IJarege and Plombieres. It seems to have been first noticed by VauqueHn,t who described several of its properties and considered it as analogous to gelatin. M. Gimbernat noticed it in 1815 in the waters of Baden, and in 1818 in those of Ischia. Aniialcii (Irr Phurinacit", p. 280. + Iliid [i. 192. i Anil. (If Cliiin. x.wix. ITo. 1 >. \ ''A il I M ll ;{ ' H |i! i !; 694 CAOUTCHOUC / M. Anglada, profesaor at Montpellier, drew up an account of it in 1827, which was presented to the Royal Academy of Medicine of Paris, on which a report by M. Boudet was read at the meeting of that learned body on the 29th of December 1827.* Glairin gelatinizes when the water containing it is sufficiently concentrated. Sometimes it is white, and at others of a red colour. W^ftn dried it shrinks to ^'gth of its bulk while moist. It has not t' . property of gluing substances together, like gelatin and albumen. It saturates ammonia, decomposes several metallic salts, and acquires different colours when acted on by different reagents. It is desti- tute of taste and smell. When decomposed it yields ammonia, showing that azote is one of its constituents. It is capable also of putrefaction like animal bodies. The general opinion entertained is, that it is of vegetable origin, and allied to ♦he genus tremella, though nobody has been able to account for its existence in mineral waters. It is the opinion of some, that the sulphuretted hydrdogen which exists in mineral waters owes its origin to the decomposing action of glairin upon sulphates originally contained in these waters. CHAPTER VIII. OF CAOUTCHOUC. About the beginning of the 18th century, a substance called caoutchouc was brought as a curiosity from America. It was soft, wonderfully elastic, and very combustible. The pieces of it that came to Europe were usually in the shape of bottles, birds, &c. This substance is verv much used in rubbing out the marks made upon paper by a black-lead pencil ; and therefore in this country it is often called Indian-rubber. Nothing was known of its produc- tion, except that it was obtained from a tree, till the French acade- micians went to South America in 1735, to measure a degree of the meridian. M. de la Condamine sent an account of it to the French Academy in the year 1736. He told them that there grew in the province of Esmeraldas, in Brazil, a tree called by the natives Hhevi ; that from this tree there flowed a milky juice, which, when inspissated, was caoutchouc. Don Pedro Maldonado, who accom- panied the French academicians, found the same tree on the banks of the Maragnon ; but he died soon after, and his papers v.ere never published. Mr Fvesnau, after "*. very laborious search, discovered the same tree in Cayenne. His account of it was read to the French Academy in 1751.t It is now known that there are at least two trees in South America from which caoutchouc may be obtained ; the havea caoutchouc, and • Jour, de Pharmacie, xiv. 76. t Mem. Par. 1761, p. 319. of it in icine of leting of [ficiently :l colour, has not Ibumen. acquires is desti- te is one animal vegetable las been le opinion in mineral lirin upon ance called It was soft, 3 of it that , birds, &c. marks made IS country it its produc- ■ench acade- iegree of the ) the French grew in the the natives which, when who accom- 3n the banks s v.'ere never 1, discovered the French •uth America outchouc, and , p. 319. CAOUTCHOUC. 695 the jatropha elaatica ; and it is exceedingly probable that it is ex- tracted also from other species of htevea and jatropha. Several trees likewise which grow in the East Indies yield caoutchouc ; the principal of these are, the Jicns indica, the artoccrpu^i integrifolia^ and the urceola elastica ; a plant discovered by Mr Howison, and first described and named by Dr Roxburgh.* Dr Benjamin Smith Barton is said to have obtained it from the juice of the smilax caduca, which grows abundantly in the neigl^bourhood of Philadel- phia.f Mr Woodcock found it in the milky juice of the asclepias vincetoxicum.X It is said also to be furnished by the castilleja elastica^ cecropia peltata, hippomene biglandulosa, and^cus religiosa. Even the papavr and lactuca are said to yield it. Probably more than one species of caoutchouc exists ; but this has not yet been established by experiment. Great quantities of it are now imported into this country both from South America and the East Indies, being employed in the manufacture of Mr Macintosh's water-proof cloth. When any of these plants is punctured, there exudes from it a milky juice, which, when exposed to the air, gradually lets fall a concrete substance, which is caoutchouc. I have received, more than once, bottles filled with the liquid as it flows from the trees in South America. But though the bottles were nearly full, and had been carefully closed to exclude all com- munication of common air, the caoutchouc had been all deposited during the passage, and had moulded itself into the shape of the bottle. Not the smallest trace of caoutchouc, could be detected in the Uquid still remaining in the bottle. Mr Faraday seems to have been more fortunate. The juice as he received it was pale yellow, thick, and similar to cream. It was covered in the bottle contain- ing it with a coating of caoutchouc, amounting to about yth per cent, of the weight of the liquid.§ Its odour is sourish and a little putrid. Its specific gravity was 1*01174. When spread in thin layers on a solid body it becomes quickly solid, and is coverted into common caoutchouc. Caoutchouc was no sooner known than it drew the attention of philosophers. Its singular properties promised that it would be exceedingly useful in the arts, provWled any method could be fallen upon to mould it into the various instruments for which it seemed particularly adapted. Messrs de la Condamine and Fresnau had mentioned some of its properties ; but Maquer was the first person who undertook to examine it with attention. His experiments were published in the Memoirs of the French Academy for the year 1768. They threw a good deal of light on the subject ; but Maquer fell into some mistakes, which were pointed out by Mr Berniard, who published an admirable paper on caoutchouc in the 1 7th volume of the * Asiatic Researches, v. 167. London Ed.tion. t Phil. Mag. xl. 66. % Ibid. 123. § The caoutchouc deposited in the bottles which I received amounted to above 40 per cent, of the whole fluid. ■| ] X-/ . 698 CAOUTCHOUC. f, Jmtrnal de Physique. To this paper we are indebted for the f neater number of facts at present known respecting caoutchouc. Ir Grossart and Mr Fourcroy have likewise added considerably to our knowledge of this singular substance ; both of their treatises have been published in the 1 1 th volume of the Amiahs de Chimie. The latest set of experiments on it was made by Mr Fai aday, and we are indebted to Dr Dalton for an analysis of the volatile oil into which it is converted by distillation.* Caoutchouc when pure has a pale yellow colour, and is destitute h of taste and smell. The blackish colour of the caoutchouc of r .mp"ce is owing to the method employed in drying it after it has bee a spread upon moulds. The usual way is to spread a thin coat of the milky juice upon the mould, and then to dry it by exposing it to smoke ; afterwards another coat is spread on, which is dried in the same way. Thus the caoutchouc of commerce consists of numerous layers of pure caoutchouc, alternating with as many layers of soot. What comes from the East Indies is in yellow cakes or pieces, having obviously been allowed to inspissate, by exposing the juice containing it to the air. Ca( .tchouc at the temperature of 32°, is hard, and possesses but lutle elasticity ; but when heated up to 60° or 70°, it becomes soft and pliable like leather. It is exceedingly elastic and adhesive ; so that it may be forcibly stretched out much beyond its usual length, and instantly recovers its former bulk when the force is withdrawn. It cannot be broken without very considerable force. Its specific gravity is 0-9335.t To the late acute philosopher, Mr Gough of Kendal, I was indebt- ed for some very important experiments on the connection between the temperature of caoutchouc and its elasticity. They have been since published in the second volume of the Manchester Memoirs, second series. It is necessary to premise, that Mr Gough had been blind from an infant, and that therefore his sense of touch was peculiarly delicate ; so much so, that he was an excellent botanist, and could distinguish plants with the utmost certainty by the feel ; a power so extraordinary, that we who enjoy the advantage of sight can scarcely conceive how it can be acquired. Mr Gough's experi- ments are as follows : — Take a thong of this substance two or three inches long, and a few lines in breadth and thickness ; put it in warm water till it becomes quite pliant : then, holding it merely extended between the two hands, bring the edge of it in contact with the lips, and observe the temperature (of the variations of which, that part of the face is a very nice judge) ; then remove the thong a few lines from the lips, and stretch it forcibly, and bring it again in contact with the lips, and a very sensible increase of temperature will be perceived. Allow it to relax to its former state, and the temperature will be perceived immediately to sink. If we stretch the thong again, and then plunge I'iiil. M.igiiziiK.' ('riiiid >Jorit?), ix. 17^. f Biisson. CAOUTCHOUC. 697 (ted for the caoutcliouc. considerably leir treatises } de Chimie. "aiaday, and atile oil into I is destitute aoutchouc of it after it has d a thin coat by exposing hich is dried ;e consists of ith as many yellow cakes , by exposing possesses but becomes soft adhesive ; so i usual length, is withdrawn. Its specific ^ Iwasindebt- jction between ley have been ?ster Memoirs, jugh had been of touch was [Uent botanist, ly by the feel ; 'ntage of sight )ugh's experi- long, and a water till it between the p, and observe [of the face is Ifrom the lips, ]\vith the lips, jived. Allow be perceived |d then plunge Blisson. it immediately into cold water, keeping it extended for a minute or more in the liquid, on letting go one end it will be found to have lost much of its contractile power ; for it will not return to its former dimensions. But if we plunge it into warm water, or warm it by holding it for some time in the shut hand, it will begin to contract again, and soon return to its former figure and size. These experi- ments are of great importance, as they furnish a very palpable and convincing proof that ductility is owing to b.tent heat as well as fluidity. They afford a fine illustration of Dr Black's theory of latent heat. We see clearly that the elasticity of caoutchouc and the ductility of metals are diff'eicnt cases of one and the same thing. Caoutchouc is not altered by exposure to the air ; it is perfectly insoluble in water : but if boiled for some time its edges become somewhat transparent, owing undoubtedly to the water carrying off" the soot ; and so soft, that when two of them are pressed and kept together for some time, they adhere as closely as if they formed one piece. By this contrivance pieces of caoutchouc may be soldered together, and thus made to assume whatever shape we please.* When caoutchouc has once become solid, it cannot be dissolved in water, alcohol, acids, or alkalies. By long boiling in water it softens and swells up, and while in that state it is acted on with greater facility by different menstrua, but when exposed to the air, it soon resumes its former st^' \ By this treatment, the black South American caoutchouc beco. -j translucent on the edges, obviously by the removal of the soot. Caoutchouc is soluble in ether. This property was first pointed out by Macquer. Berniard, on the contrary, found that caoutchouc was scarcely soluble at all in sulphuric ether, which as the ether used by Macquer, and that even nitric ether was but an imperfect solvent. The difference in the results of these two chemists was very singular ; both were remarkable for their accuracy, and both were too well acquainted with the subject to be easily misled. The matter was first cleared up by Mr Cavallo. He found that ether, when newly prepared, seldom or never dissolved caoutchouc com- pletely ; but if the precaution was taken to wash the ether previously in wa^ T, it afterwards dissolved caoutchouc with facility. Mr Grossurt tried this experiment, and found it accurate.! It is evident from this that these chemists had employed ether in different states. The washing of ether has two effects. It deprives it of a little alcohol 'vltli which it is often impregnated, and it adds to it about y'j^th of water, which remains combined with it. Alcohol preci- pitates the caoutchouc from this solution. When the ether is evaporated, the caoutchouc is obtained unaltered. Caoutchouc, therefore, dissolved in ether, may be employed to make instruments of different kinds, just as the milky juice of the hrevea ; hut this method would be a great deal too expensive for common use. * Giossart, Ami. de Cliiin. xi. I.j3. Sec a method uf mpkiii}^ caoutchouc tubes by uipaus of lliis properly, Phd. Mug. xxii. 340. f {'iro.^i^iirt, Ann. de Cliini. xi. 147. ■%'i , m 698 CAOUTCHOUC. ( Caoutchouc is soluble in volatile oils ;* but, in general, when these oils are evaporated, it remains somewhat glutinous, and there- fore is scarcely proper for those uses to which, before its solution, it was so admirably adapted. Coal naphtha was found by Mr Mac- intosh, capable of dissolving caoutchouc by the assistance of a long- continued heat. It is this solution, spread in numerous coats be- tween twi folds of cloth, that renders the cloth water-tight. The quantity of naphtha required for this solution is now so great, that enough of it cannot be procured for the purpose, notwithstanding the numerous coal-gas works scattered over Great Britain. Great quantities of oil of turpentine are also employed ; for it has been long known that oil of turpentine and coal naphtha, are almost identical in their properties. Caoutchouc dissolves both in the fixed and volatile oils ; but when the solutions are dried, the caoutchouc remains in an adhesive state and destitute of elasticity. According to Achard, it is not soluble in oils of lavender, cloves, cinnamon, nor lintseed, nor in Dippel's animal oil. But this statement is not likely to be correct. Lam- padius found that when put into 4 times its weight of bisulphuret of carbon, it becomes soft. If in this state we put it into 16 parts of new bisulphuret of carbon, and stir the whole frequently, we obtain in a few days a milky liquor, which leaves the caoutchouc, when evaporated, in its original elastic state. It is said by Berniard to be insoluble in alkalies ; but I iind upon trial that this is a mistake. I was led to make the experiment by an accident. I employed a caoutchouc bottle fitted with a stop-cock in the usual way for holding ammoniacal gas. The gas very soon disappeared, though the bottle was perfectly air-tight, as I learned by plunging it in water. This induced me to fill it repeatedly with gas. In a short time it became evident that the gas had been absorbed by the bottle itself. It became soft and then glutinous, and never recovered its elasticity. I than tried the alkalies in general, and found that they were all capable of producing the same changes on caoutchouc, and even of dissolving it, though in a very minute proportion. The acids act but feebly upon caoutchouc. Sulphuric acid, even after a very long digestion, only chars it superficially. The proportion of charcoal obtained in Mr Hatchett's experiments was only 12 per cent, and he could observe no traces of artificial tannin.f But when heat is applied the caoutchouc is completely decomposed. When treated with nitric acid, there came over azotic gas, carbonic acid gas, prussic acid gas; and oxalic acid is sa:d to be formed.^ Muriatic acid does not affect it.§ The other acids have not been tried. When heated to a temperature of about 248°, it melts, and on cooling, remains in a semifluid adhesive state, somewhat like tar, or * Berniurd. f Third Series of Experiments on Artificial Tannin, Phil. Trani. 1806. l Ann. de Chim. xi. 232. § Berniard. CAOUTCHOUC. 699 rather turpentine. In this state, in close vessels, it remains unaltered for years, but when spread in thin layers and exposed to the air, it gradually, but very slowly acquires hardness. After fusion, it still continues insoluble in alcohol of 0*815, or nearly so. It is equally little soluble in the caustic alkalies. When caoutchouc is heated sufficiently in the open air, it smokes, giving out an odour which is not disagreeable, it then catches tire and burns with a strong yellow flame, giving out much smoke. It was ascertained some years ago, by Messrs Beale and Enderby of London, that when caoutchouc is distilled in close vessels, it furnishes 831^ per cent, of volatile oil. There passes oif at the same time, a quantity of combustible gas, but neither carbonic acid, water, nor ammonia. This seems to show that caoutchouc contains neither oxygen nor azote. The oil has at first a dark colour, but when repeatedly rectified it becomes limpid and colourless, and has a specific gravity of only 0*640. It begins t.. boil at 95°, but during the boiling it rises as high as 149°. It is obvious from this that it is not homogeneous. Its boiling point, as determined by Dr Dalton, is 108°. And the elasticity of its vapour, is nearly the same as that of ether at the same temperature. It evaporates rapidly, and the evaporation is attended with the evolution of a good deal of cold. Dr Dalton found that its vapour was not absorbed by water. Of course air or oxygen gas impregnated with it over water, acquired a certain augmenta^ tion of bulk according to the temperature, which augmentation of bulk was permanent. Dr Dalton took the specific gravity of this vapour, and found it 2*00. He found that when this vapour was mixed with oxygen gas, in the requisite proportions, it detonated by the electric spark, and was converted into carbonic acid gas and water. 1 volume of the vapour requires for complete combustion, 6 volumes of oxygen gas. The product is 4 volumes of carbonic acid gas and water, and nothing else. It is clear that 4 volumes of the oxygen gas, went to the formation of carbonic acid, and 2 volumes to the formation of water, which would require 4 volumes of hydrogen gas. Hence this vapour is composed of 4 volumes carbon vapour, and 4 volumes hydrogen gas united together, and condensed into one volume. 4 volumes carbon weigh . I "6666 4 volumes hydrogen gas . 0*2777 1*9444 Hence the true specific gravity is 1*9444, and it is a tetarto-carbo- hydrogen ; or the same as 2 volumes of olefiant gas condensed into 1 volume. The oil in the liquid state must be a compound of Carbon 85*71 Hydrogen .... 14*29 100*00 700 CAOUTCHOUC. According to Mr Faraday's analysis, the liquid from which caout- chouc is deposited, is composed of Water* 56-37 Caoutchouc Albumen Wax, a trace An azotic bodyf Gummy body 31*70 1'90 7-13 2'90 100-00 Mr Faraday also analyzed caoutchouc, and found it composed of Carbon 87*2 or 8 atoms = 6 or per cent. 87-27 Hydrogen 12-8 or 7 atoms = 0-875 — — 12-73 100-0 6-876 100-00 The probability is, that it is composed of an equal number of atoms of carbon and hydrogen. If we were to consider the volatile oil obtained by distilling the caoutchouc, as exhibiting its constitution correctly, it would consist of 4 atoms carbon . . . =3-0 4 atoms hydrogen . . . =0-5 This would give the constitution, per cent. Carbon .... Hydrogen 3-5 85-72 14-28 100-00 Dr Gregory found that when this oil was mixed with sulphuric acid in small quantities at a time, cooling it after each addition, and corking the tube in which the mixture was made, we obtain a liquid swimming over a brown matter, and amounting to about half the oil employed. This liquid being washed with water and potash, fur- nishes an oil having an aromatic smell, and boiling at 437°, or a little higher. This new oil is composed of the same number of atoms of carbon and hydrogen. Liebig conjectured it to be eupion, but Dr Gregory does not think this likely.| Caoutchouc has of late years, in London, been rolled out into thin sheets, which are exceedingly useful in the laboratory, for joining glass tubes together, so as to make the joint air-tight, and at the same time preserve its flexibility. Bottles of it, or rather balloons, blown thin by steeping the American little bottles of it in ether containing alcohol, and blowing them out to the requisite size, are convenient for holding small quantities of gas without altera- * The water held in solution a little free acid, which precipitated nitrate of lead, mid gave a green colour to the persalts of iron, without occasioning any |)recipitate. t Tliis substance had a bitter taste, and was soluble, with a brown colour, in water and alcohol. i Jour. '2. CAOuTCHoi;r, 701 tion. The quantity consumed in this country, in the manufacture of water-proof cloth, is very great indeed. In those countries where it is indigenous, it is apnlied to a vast viiriety of uses ; shoes, hoots, cloaks, &c., are made of it, which, fro... being impervious to water, are found extremely convenient under a great variety of circum- stances. A set of experiments on the products of the distillation of caout- chouc, has lately heen made hy M. Bouchardat.* By distilling at a low temperature, and exposing the jjroducts to the action of a freezing mixture surrounding the receivers, he obtained five different liquids. 1. Eupion. A colourless limj)id liqiiid, of the specific gravity 0*69. It boils at 124°, is insoluble in water, but soluble in all pro- portions in absolute alcohol, and is not acted on by acids or alkiilies. 2. Tetarto-cnrbo-hydrogen, or the carburet of hydrogen of Faraday. 3. Caoiitchene. This is an oily substance, which is distilled over by subjecting the product of the distillation of caoutchuc to a tem- perature between 50° and 64°. This substance, when exposed to a freezing mixture, crystallizes in long needles. When obtained by compression, it constitutes a white opaque mass. It melts at 14° into a transparent liquid, which boils at 58°, and has a specific gravity of 0*65. It is insoluble in water, but very soluble in abso- lute alcohol and in ether. Alkaline solutions do not act upon it. Sulphuric acid acts upon it as upon tetarto-carbo-hydrogen. Ac- cording to Bouchardat, it is composed of Carbon ..... 86"65 Hydrogen . . . . 14" 18 99-83t This is obviously 1 atom carbon, and I atom hydrogen. It is, therefore, one of the numerous tribe of carbo-hydrogen. How many atoms of each constituent it contains we do not know, as the specific gravity of the vapour of caoutchene has not been deter- mined. 4. Heveene, This is an oily body, wliich remains after the vola- tile oils are distilled oft' along with water. It is a transparent liquid, having a light amber colour, an empyreumatic smell, and an olea- ginous consistence. Its taste is acrid, and it boils at 600°. It does not become solid, though exposed to the most powerful refrigerents. Its specific gravity is 0*921. It burns like the volatile oils, giving out much smoke. It is soluble in all proportions in alcohol and * Jour, de Pharmacie, xxiii. 454. f These numbers do not agree with his own data, according to which the com- position should be Carbon 94*04 Hydrogen 14'73 108-79 There is doubtless a typographical error in some of the figures. i'i Xm ill III i R^BT t I i ■ti. If 702 exthactivu. ether, and in the (ixcd and volatile oiid. It neither acta as an acid nor alkali. It a constituents were found to be Carbon 8()-22 Hydrogen .... 13*99 100-21 obviously another of the carbo-hydrogen tribe, already so numerous. It absorbs chlorine, thickens, and gives out muriatic acid. In the same way it combines with bromine and iodine. It thickens also when acted on by alkalies, and absorbs oxygen. Sulphuric acid darkens the colour. If the mixture be left for some days, a colourless liquid swims upon the surface, which pos- sesses the characters of eupion. The fifth product has not been described. CHAPTER IX. OF E X T il A C T I V E. The term extract (exlraclum) was employed by apothecaries to denote that portion of any vegetable substance which had been dis- solved by digesting it in any menstruum whatever, and which had afterwards been reduced to a thick consistence, by distilling off the menstruum, if valuable, or by evaporating it away, if not worth preserving. So that originally, the portions of plants dissolved by water, alcohol, wine, acetic acid, carbonate ot potash, &p., and afterwards inspissated, were called extracts. This is the meaning which the word bears in the Pliarmacopee Rot/ale Galenique et Chy- mique ofCharas, published at Paris in 1676.* Thus the extract of opium of Charas was made by digesting opium first in water, and afterwards in alcohol, till every thing soluble in these menstrua had been taken up. The two solutions were mixed, the alcohol distilled off, and the wr';er evaporated in a gentle heat. What remained was called extract of opium. In process of time, these extracts were divided into two sets ; namely, watery and spirituous, or yummy and resinous, according as the menstruum employed was water or alco- hol. This distinction was attended to in the time of Neumann.f Afterwards the term extract came to be restricted to what was ob- tained from vegetables, by macerating them in water, and evapo- rating the watery liquid to dryness. The extracts obtained in this way were generally considered as soaps, till Fourcroy and Vauquelin published some observations on the subject in 1790.$ According to them, extract is a substance at first soluble in water ; but which, when the solution is exposed to the air, absorbs oxygen, and becomes insoluble. Chlorine gas * See pajje 7-21. f Sco Ncuiniinn's Clicinislry, p. 268. t Ann. de Cliiin. vi. 180. EXTUACTIVK. 703 as an acid a numerous. c acid. In It thickens ! be left for , which poa- othecaries to had been dia- ,nd which had stilling oft' the if not worth 3 dissolved by \sh, &P., and s the meaning eniqiie et Chi/- i the extract of jn water, and 1 menstrua had Icohol distilled Vhat remained e extracts were or yummy and , water or alco- of Neumann-t what was ob- ter, and evapo- y considered as observations on s a substance at n is exposed to Chlorine ga3 5try, p. 268. speedily converts it into a solid yellow substance insolul)le in water, but soluble in alcoiiol and alkalioi^. They inform us that they exa- mined 12 different extracts, and found the same charactcrrt in all. In tiie vear ITOl titey published an elaborate analysis of thq Cinchona bark of St Domingo, in which a great many experiments on extract aro stated.* And soon after, Vau(iuelin made a sot of experiments on the extractive principle of vegetables.f Fourcroy, in nis General System of Chemical Knowledge^ published about the beginning of the present century, recapitulates the facts ascertained previously by Vauquelin and himself. The extracts from vegetables are very complex in their nature ; but they all, in his opinion, con tain a peculiar principle, to which he confined the term extract Accordmg to him, it possesses the followiug properties : — It is at first soluble in water, but rapidly absorbs oxygen from the air, or other substances capable of yielding it. By this abaorpticiO, it acquires a brown colour, and becomes insoluble in water. It has a strong affinity for alumina, and is taken away, and the liquid dis- coloured, when alum, mixed with an alkali, is agitated in a solution containing extract. Fourcroy was of opinion that extract was not perfectly identical, but possessed different characters, according to the plant from wl .;;!> it was extracted, though every specicH of extract po'^'essed the properties above stated. Ilis notions on the subject, ho ,o,' r, were too crude and unsatisfactory to merit a lengthened deta 1. Saussurc afterwards showed that the substance called extract or extractive^ by Fourcroy and Vauquelin, did not combine with the oxygen which was absorbed, but gave out hydrogen to it, so as to convert it into water. The extractive, therefore, was not rendered insoluble by uniting with oxygen, but by being deprivel of hydro- gen. It contains a greater proportion of carbon than it did when soluble in water, and hence doubtless the reason why it assumes a brown colour. Berzelius has distinguished this brown extractive by the name of apotheme (by which he means deposite).^ It possesses the following properties. It is not completely insoluble in water, - o^vinunicating a yellow, reddish-brown, or red colour to that liquid, and is again deposited when the liquid is evaporated. But it is dissolved with very great difficulty, and a minute portion of it cmmunicates a good deal of colour to that liquid. Boiling water dissolves more than cold, and the excess is deposited as the solution cools. It is much more so- luble in alcohol than in water, and more soluble in hot than in cold alcohol. Its best solvent is caustic potash, which dissolves a great quantity of it, and assumes a deep brown colour. The alkaline carbonates dissolve it also. The acids throw it down from these solutions. The apotheme thus set at liberty, combines with the excess of • Ann. de Chira. viii. 113. t ^our. do la Soctet. des Pharm. iv. 13!]. t Traite de Chimie, v. 548. n >:\i 1 J niTTEB PRINCIPLES. Z en,pMea to t.J™w U aow^X^^^tlt^y ^^ ^ modern "^'r"!'- I'sU oraP"*''"^ " "' I""'' * ^''hra^Sl or&ntjlants. ,^^ ,.,„,„, „trac., and extraciea ^^ count oi ^^^^^^ ^ phoric acid. II CHAPTER X. iirrrSs,tLr.eLre.^^^^^^^ &d substances differ f ™™J»' '" *ed. There does not, then, ^^t wfhitC been "y i^PerfecUy h«e^.ga^«l. ^.^^^^ "Ta'^^'elr^'tn ^^r t'^^d "Hh^^"-:' T ^SC ^%Ei£lt;areso™eonhe.o.re™ar.ah,ehUter*tane. bitherto «^a"^^"«^--7j^„^ de Pharmcie. xVu. 172. BITTER PRINCIPLES. 705 rty of red- mbine witb t it 13 very Jering from ,ve been ob- attention of this subject, as possible, rent extracts all contain a ir ingredients them. When ure, they all mbined phos- jr taste, and on s, &c. This is xcelsa, the com- gentiana lutea, lus, ovhop; the mon broom; the mile ; and many ination of these . that these bitter ters, according to e does not, then, .racters on all the t bitter principles gated. vt when the bitter joal, in a tempera- sr taste, either en- , infusion of arnica, IS benedictus, cha- Gentian, quassia, ttle altered by this till more powertuliy ble bitter substances 1 . Quassite. This name has been given by Wiggers to the bitter principle of the quassia amara and excelsa* He procured it by the following process: — The sliced wood was boiled in water, and the filtered decoction was esaporated to |;th of its bulk. After cooling, it was mixed with a quantity of dissolved lime ; and the mixture was frequently agitated for 24 hours. Pectin, and some other substances, were separated by the lime. The tillered solution was now evaporated to dryness, and the residue treated with alcohol of specific gravity 0*83 1. The quassite was dissolved, together with some common salt, saltpetre, and a brown colouring matter. When the alcohol was distilled ofl', and the residue evaporated to dryness, a light- yellow crystalline matter remained, which was dissolved in as small a quantity of absolute alcohol as possible, and mixed with a little ether. This solution was filtered and evaporated. These solutions and evaporations were repeated till the quassite was obtained pure. Quassite thus obtained, possesses the following properties: — It is crystallized in very small white prisms. But, for the formation of these prisms, the presence of water is necessary. Its taste is in- tensely bitter. It has no smell, and is not altered by exposure to the atmosphere. 100 parts of cold water dissolve only 0*45 of quassite. But the solubility is increased by several salts and vege- table principles. This solution is precipitated white by tannin, but not by iodine, chlorine, corrosive sublimate, salts of iron, ac.-jtate, or subacetate of lead. It is very little soluble in ether. The best menstruum is alcohol, which acts more powerfully, the stronger and the hotter it is. Hence a saturated solution of quassite in absolute alcohol becomes muddy when a little water is added, •"nd the quassite may be redissolved, by adding to the alcohol a sufficient quantity of water. The alcoholic solution is not thrown down by acetate or subacetate of lead ; but it is by corrosive sublimate. All its solutions are colourless. It is a neutral body. Sulphuric and nitric acids dissolve it, but do not lose their acid qualities ; and the nitric acid of the specific gravity 1*230, may be driven off by heat, leaving the quassite unaltered. When heated it melts like a resin, and its point of fusion is only a little higher than that of common rosin. On cooling it forms a translucent yellowish mass, which is very brittle. When heated to 212° in a dry atmo- sphere, it loses about 1*3 per cent of its weight; and when fused, the loss amounts to 1*76 per cent. When more strongly heated it becomes brown, and is charred. Quassite, according to the analysis of Wiggers, is composed of Carbon 65*75 or 10 atoms = 7*5 or per cent. 66*66 Hydrogen 6*89 or 6 atoms = 0*75 — — 6*66 Oxygen 27*36 or 3 atoms = 3*0 — — 26*66 100*00 11*25 100*00 * Annalen der Pharmaeie, xx!. 40. 2 z I I f 1. 1 • a 706 DIT^TER PRINCIPLES. ^!^l u 2. Gentianite. This substance, from the gentiana lutea, has been very imperfectly examined by M. Leconte.* The alcoholic extract of the root contains it in the state of greatest purity. When this extract is treated with water, an excessively bitter solution is ob- tained, which reddens litmus paper. Subacetate of lead throws down the acid. A current of sulphuretted hydrogen throws down the lead from the liquid, and leaves an extract very bitter and sweet, which is very soluble in water. Ether dissolves from it a fatty matter, or oil, resin, and wax. The bitter principle and sugar still remain, and have not been separated from each other. From the latter experiments of Trommsdorf, it appears that the crystallized substances from the root of gentian, obtained by Henry and Crvei)- tou in 1821, but first purified by Trommsdorf, is tasteless, has a sulphur-yellow colour, is insoluble in cold, and but slightly soluble in hot water, but soluble in alcohol and ether. It may be sublimed in yellow needles. It seems to be a neutral substance, and cannot be the body to which gentian owes its bitterness.! 3. Cytisite. This substance was obtained by Chevalier and Lassaigne, in 1818, from the seeds oi the cytisiis laburnum.\ The process followed was the following : — The alcoholic extract of the seeds was treated, and the solution precipitated, by acetate of lead. A current of sulphuretted hydrogen gas was passed through the filtered liquid. It was filtered again and evaporated. It is a greenish-yellow bitter-tasted substance, readily soluble in water and alcohol, and precipitated by diacetate of lead and nitrate of silver. When taken internally to the extent of 8 grains, it was found to act with great violence, producing vertigo and violent spasms, quickening the pulse, and occasioning vomiting. These symptoms lasted about two hours, and left a prostration of strength, which continued a long time. It is, doubtless, to the cytisin that the berries of the cytisus laburnum owe their poisonous qualities. 4. Bryonite. This substance was discovered, in 1807, by Vau- quelin, in the root of bryonia alba, as white bryony.^ It was extracted by Brandes and Firnhaber. by the following pro- cess: — II The filtered juice was raised to the boiling temperature, and filtered again. It was now mixed with diacetate of lead. The precipitate was washed and decomposed by sulphuretted hydrogen. The solution thus obtained was evaporated to dryness, and the dry residue being digested in alcohol, the bryonite was dissolved. The process of Dulong^ was the following: — The expressed juice of the root was mixed with water, and left at rest. Starch was deposited, which was separated, and washed with a little water. The filtered liquid being raised to the boiling temperature, the albumen coagulated, and was separated by the filter. The liquid • Jour, do Pharmiioic, xxiii. 470. + Ann. dor Pharinacic, xxi. 1.'34. X .Tonr. 'ie Pliiinnacie, iv. 340. § Ann. rle Mus. d'llist. Nat. viii. 88. Ij Br. Arcli. iii. 3oI. \ Jour, dc Piiarmacie, xii. 158, a'2;>, 507. lias been 3 extract hen this on is ob- d throws )ws down nd sweet, t a fatty ugar still From the ■ystalUzed id CpveUr ess, has a ;ly soluble I sublimed md cannot i^alier and im.X The [le solution d hydrogen tered again r soluble in and nitrate ■ains, it was and violent no-. These of strength, cytisin that qualities. 07, by Vau- )llowing pro- erature, and lead. The ed hydrogen. , and the dry solved, he expressed •est. Starch a little water. peratu re, the The liquid ie, xxi. 1.34. . Nat. viii. H8. P, a'2r., 507. P UrrXER I'UINCIPLES. 707 was now evaporated to the consistence of an extract. This extract was digested in hot alcohol till every thing soluble was taken up. The alcoholic solution was distilled, and the residue treated with water, which left a little resin undissolved. The aqueous solu- tion being gently evaporated, the bryonite remained in a state of purity. Bryonite thus obtained, is a yellowish-brown extractive-looking substance, having an exceedingly bitter taste. It is soluble in water. Alcohol dissolves it better when it contains water, than when anhy- drous. In ether it is insoluble. It contains azote, and when distilled furnishes ammonia. It possesses neither acid nor alkaline |)roperties, and cannot be obtained in crystals. Chlorine does not act upon it. Concentrated sulphuric acid dissolves it, assuming at first a blue colour, and then a green, so deep, that it is difficult to distinguish it from black. Nitric acid dissolves it, forming a liquid, at first brown, but becoming speedily yellow, from which water throws down a light yellow precipitate. If we heat the solution, nitrous gas is given out ; and when we evaporate to dryness a yel- low resin remains. Muriatic acid dissolves it with nearly similar phenomena. The caustic alkalies dissolve bryonite without altering it. Its solution in water is not precipitated by acetate or nitrate of lead, protochloride of tin, tartar emetic, nor by the salts of zinc, iron, or copper.. But it is precipitated white by nitrate of silver, yellow by chloride of gold, and in great abundance by nitrate of mercury and subacctate of lead. The infusion of nutgalls throws down a copious grey precipitate, diflScultly soluble in water ; but more easily in alcohol 5. Centaurite. This name may be given to the bitter substance which exists in the leaves of the centaurea beiiedicta, or blessed thistle. It was extracted by M. Morin, in the following way : — * When the dried leaves are digested in alcohol, that liquid dis- solves a green resin mixed with a fat oil, a brown resin, the peculiar bitter principle to which the centauria owes its qualities, extractive, sugar, and nitre. The alcoholic extract, when treated with ether, gives out the green resin, the fat oil, and the bitter principle. When the portion insoluble in ether is treated with water, the brown resin remains undissolved. When acetate of lead is dropt into the aqueous solu- tion, a precipitate of malate and phosphate of lead falls, the acids of which salts exist uncombined in the sulution. The diace- tate of lead then precipitates the extractive and its apotheme. If we pass a current of sulphuretted hydrogen through the liquid precipitated by the salts of lead, and evaporate after filtering, the liquid, when sufficiently concentrated, concretes into a crystalline mass. When this mass is treated with alcohol of 0*81, sugar and bitter principle are dissolved, and nitre remains. Evaporate the * .lour. (Jliein. Mod, iii, lOJ \ ' HITTER PniNClPLES. ''OS f , svruT), and agitate it for a tains the bitter pi r n^^Uh-brown colour, the sugar. ^^^ goVul, has a rf{f ''" ammonia. It Its taste is ^^\y.)'X'v,J;v ; and the boil^g- ^«^^f f^^t ^.^^ents. rikalies render .ts colon ^^^^^ ^.^^^j^_^^ -lW*e.eave»J-tHS i-^^.s^^^^^^^^^^ It is colourless, f'™"'."', insoluble >n ether, fi'-f : ^" „ action '^f'^Tttlt^St' n >;as a ^LCwa e" S^y ether, oils. rnf,^t? r= It is rendered muddy oy . ^f nutgalls. acid. 1 tie ve^ auantity, m the n-rthanitite is said also to e.ist, though ^ ahsynthinm, or ^«7';^^;^^' b??ie following P7t'Tn7ecipitated by obtained by M. ^^'f^^\;^Ss\on of wormwood ^^ P/^^^f ^^iphu- A very concentrated i"i"=J" fiitt^red 1 quid a current oi t- ^i? 1 .A Through the tiltercu » i excess ot leau. acetate of lead. Y' mssed, to throw ^own any e .g^^^ce of an extract. li»is txt * Beuclius. TraU6 de ChunU., vl. 185. UlTTER PIUNCIPLES. :o9 it tor a le liquid top con- contains n colour, onia. It I solution solvents, t precipi- . of lead ; lixed witli it. The into oxalic dissolves d there re- • basin witli »liur. ic Cyclamen hicli be dis- is employed , obtained it in water, and was digested en up. iip oration, Tbe tbe )f cold water, d, and volatile D has no action • and by ether, ion of nuttralls. •ts it into oxalic ily than water quantity, in the )f the artemisia .pie, which was precipitated by irrent of sulphu- excess of lead, o the consistence fixture of 4 parts alcohol, and I part ether, till every thins^ soluble was dissolved. The bitter principle was taken up, and when the alcoholic liquor was evaporated, it remained behind, in a hard brown friable mass. It has the peculiar bitter taste which characterizes wormwood. It does not crystallize. When distilled in a retort it is completely de- composed.* M. Meln has endeavoured to show, that this bitter principle pos- sesses resinous characters. But from the process followed in procuring it, we see that it was soluble in water .f 8. Colocynthite. This bitter principle Is contained in the fruit of the cucumis colocynthis, or colocynth of apothecaries. It was first obtained in a separate state by Vauquelln. The following is the process which may be employed: — Boll the ])ulp of colocyntli in water, evaporate the decoction to dryness, and treat the residue with alcohol, which leaves the gum but dissolves the colocynthite, together with some acetate of potash. Evaporate the alcoholic solution, and treat the residue with a small quantity of water, which dissolves the acetate and leaves the greater part of the colocynthite in a state of purity, Colocynthite thus obtained is a yellowish-brown or reddish matter, translucent, brittle, and easily reduced to powder. It restores the blue colour to litmus paper reddened by an acid. When heated it burns with flame like a resin, and when distilled, furnishes a little ammonia. It requires five times its weight of cold water to dissolve it. It is much more eoluble in hot water, and nothing Is deposited when the liquid cools. It is soluble also in alcohol and ether. Chlorine throws down from the aqueous solution a precipitate soluble in alcohol. Acids and the very deliquescent salts, such as, chloride of calcium and acetate of potash precipitate it from its solution in water, under the form of a coherent and adhesive mass, which does not dissolve in water, and which appears to be identical with the colocynthite of Vauquelln. The aqueous solution of colocynthite, is not precipitated by alkalies, or by barytes, or lime water. The protosulphate of iron, the sulphate of copper, and the nitrate of mercury precipitate it ; and it is slightly precipitated by corrosive sublimate, nitrate of silver, and acetate of lead. Infusion of nutgalls throws it down copiously : the precipitate is a light yellow matter, and so thick that the vessel containing It may be turned upside down without s})llllng any thing. This precipitate is soluble in alcohol and in boiling water ; but is deposited from this last solution as it cools. This colocynthite is supposed to constitute the active part of the pulp used in medicine as a drastic purgative. !). Bitter principle of aloes. This bitter principle has been already described while treating of aloes, which we placed among the gum resins, in compliance with the usual practice of writers on Materia Medica. II i! ;• •■-. m * Joiir. clu I'liiinnai'ir, xiv. 677. \ Ann. iIlt Pliarm. viii. Gl. •ffffiit^plMi^. W^'^Svmw^'%m'\ 710 iUTTKU I'lUNCIl'LES. '!( i' f A 10. Xanthopicru'e. This substance was detected by Chevalier and Pelletan, in th*^ bark of the Xanthoxylon carybcciim.* The bark was digested in alcohol, and the spirit beings distilled off left an extract, which was digested first in water, and afterwards in eth!> ■. What remained undissolved was taken up wild alcohol, and the alcoholic volution being evaporated cry.stalsdf xaati'opicilJo were deposited. This sni 'Stance has a greenish-yellow colom- and a silky luslip, It has no smell, but a very bittvr and nstrinj/i i".t tuft* '. ^ is i'.d; altered by exposur(; to the air, and proluccs no change upon v( ;:,■(' table colours. Wiien heated it is par fiy deco.r posed, and partly sublimes unaltcved. It is but little sululilo in watoj', and not at all soluble in ether. It is readily soluble in alcohol, especidly wlien assisted ])y iieat Chlorine hjt>' but little ajtion on it, anti a solution of xauth' picrite containing cidorine may be freed from jt, '".tlior by a r.^ .*(\ evapova- tlciij, or by yatm*ating tlie chlorine with aii alkali, withu '.t altiiring tl".> KanUiopicrite. The long-continued action of ciilorine occasions the dcpo.-ition of a brown-coloured precipitate. T!,i' idorite of soda completely decomposes xanthopicrite. Snl- phurio i'iid giv^s it a brown colour; but when the acid is saturated with an alkali, the brown colour disappears. When long boiled with dilute sulphuric acid, xanthopicrite «"iianges its nature, it loses the property of crystallizing, and when the acid is thrown down by chalk, it yields a brownish-yellow extract, having an exceedingly bitter taste. Nitric acid gives xanthopicrite a red colour. Muriatic acid has no sensible action on it. No precipitate appears when solutions of xanthopicrite are mixed with the earthy or metalline salts. But a good many of these salts when poured into solution of xanthopicrite, throw it down in the form of orange-coloured flocks, which dissolve when water is added to the liquid. Chloride of gold precipitates xanthopicrite, the precipitate is a compound of the chloric' e and of xanthopicrite. It is insoluble in water, and gives with chloride of tin the purple of Cassius, and with nitrate of silver chloride of silver. The tincture of the xanthoxylon caryhocum or clavatum is used in the West Indies as a remedy for the toothach, and according to Chevallier and Pelletan, it owes its medicinal qualities to the xan- thopicrite which it contains. 1 1 . Berherite. Berberite is a bitter tasted substance, extracted from the bark of the herberis vulgaris or barbery. It was first obtained in a state of purity by M. Buchner, senior, in 1835, and its properties were afterwards determined in detail by M. Buchner and his son.f It m.ay be separated from the bark of barbery root by the following process : The root reduced to small pieces is digested in boiling water for some hours. This digestion is rc])eated till every thing soluble i.-^ * ^la^'. I'lianii. xvii. 7.j. -j- Jour, do Pluirinacic, x\ii. 40,. and xxi. ;)0{>, 40>S. UITXJiU 1»,.'.1NCII'LES. 711 mce, extracted ^ilinff water for taken up. The watery liquids thus obtained are mixed and evapo- rated to the consistence of a soft extract. This matter is digested in hot alcohol of 0'H44 repeatedly, as long as thejicjuid continues to acquire a bitter taste. These tinctures are filtered, and the greatest part of the alcohol is distilled off. The residue is left in an open vessel in a cool place. In 24 hours feather-shaped crystals are deposited of a yellow colour. They are to be separated as exactly as possible from the brown and unctuous matter in wliich they are immersed, by subjecting them to pressure in a fine cloth, an(l washing them with cold water. When tiiese crystals are treated with boiling water, they dissolve and are deposited when the liquid cools in a very bulky crystallized mass ; while the greatest part of the impurities remains in solution. If this precipitate be dissolved twice successively in boiling alcohol, and allowed each time to crystallize as the solution cools, it is rendered (piite pure. By this process the MM. Buchners obtained 1"3 per cent, of the weight of the bark employed of berberite. Berberite has the aspect of a very light powder, composed of minute needles, having a silky lustre and a beautiful yellow colour. When the alcoholic solution is cooled very slowly, the crystals are small prisms united in groupes. It has no smell, but its taste is intensely bitter, and it continues long in the mouth. It has no action whatever on vegetable colours, excepting that it renders litmus paper green, it is very little soluble in cold water, yet it communicates a yellow colour to that liquid. At the temperature of 59° it requires 500 times its weight of water to dissolve it. At the temperature of 54°, I part of berberin dissolves in 250 parts of alcohol of 0*844. Boiling water and alcohol dissolve it in every proportion, but most of it falls down again when the solutions cool. Oils of lavender and turpentine only assume a very faint shade of yellow when left in contact with ber- berite. It is quite insoluble in ether, both cold and hot. It is in- soluble also in bisulphuret of carbon and naphtha. When concentrated sulphuric acid is poured on berberite, a solu- tion takes place, the liquid assumes an olive-green colour, and the berberite is destroyed. W'hen the liquid is diluted with water, it loses its colour, and a deep-brown precipitate falls insoluble both in alcohol and ether, lit is dissolved by the caustic alkalies, and throwp dov/n again by acids in brown flocks. Nitric acid dissolves it with a strong effervescence, forming a deep-red liquor. When heated, the red colour vanishes, the solution becomes yellow, and at last almost colourless, and crystals of oxalic acid are deposited. It is precipitated from its solutions by concentrated sulphuric, nitric and muriatic acids ; by liquid phosphoric acid, and in general by all acids, which have a strong affinity for water. Acetic acid, tartaric, racemic, citric and oxalate acids dissolve berberite like water. But the infusion of nutgalls or tannin throws it down in vellowii^h-hrown flocks^. !< m\ I- 1 \i tiii «Ui>«. 712 BITTEn PRINCIPLES. H'f i , The alkalies and several eartliy bodies render the colour of ber- berite less distinct, and form compounds, which allow the yellow colour to appear, when these alkaline bodies are saturated with an acid. When ammonia is poured into a solution of berberite, it strikes a yellowish-brown colour. It dissolves a little berberite but not more than the same quantity of water would do. If we heat the liquid to drive off the ammonia, and then evaporate in a gentle heat, small brown crystals are deposited, having the bitter taste of berberite. When heated with potash they give out the smell of ammonia. When treated with an acid they assume tlie yellow colour of berberite. Solution of potash gives berberite a reddish-brown colour with- out disengaging any ammonia. If we boil this solution most of the berberite comes to the surface and melts, and on cooling and wash- ing has a liver-brown colour, a resinous aspect and a bitter taste. It is little soluble in water, but more soluble in alcohol. The alcoholic solution being evaporated gives small brown crystals. They dissolve in acetic acid without changing their colour. But muriatic or any other strong acid causes them to resume the yellow colour of berberite. Soda acts precisely as ])otash. Lime- water and solution of alum have no sensible action on the solution of berberite. With most of the solutions of the metallic oxides it forms preci- pitates, insoluble in water or nearly so, and the liquid loses its colour. It is thrown down yellow by nitrate of mercury, corrosive subli- mate, nitrate of silver, chlorides of tin, nitrate of cobalt, tartar emetic and chloride of manganese. Perchloride of iron, nitrate of bismuth and chlorides of gold and platinum throw it down oraugc. Sul- phates of copper and nickel throw it down greenish-yellow. Acetate and subacetate of lead occasions no precipitate, even after standing 24 hours. Nor is it thrown down by sulphate of zinc and the pro- tosalts of iron. A current of chlorine gas passed over dry berberite gives it a red colour, and it becomes easily soluble in water. If we continue the current, a blackish-brown ])recipitate falls, and the solution becomes gradually light-brown. The precipitate is tasteless and insoluble in water, partly soluble in boiling alcohol, but readily soluble in dilute potash. Berberite is readily destroyed by heat. At a heat a little above that of boiling water it assumes a reddish tint, but resumes its yellow colour on cooling. Heated on platinum foil it melts, swells, gives out a disagreeable smell, burns with flame, and leaves a charcoal difficult to incinerate. When distilled it gives out water at 212°, assumes a brown colour at 266°, melts at 320°, and a yellowish liquid distils over. At 428° it swells and leaves a charry residue, having a strong metallic lustre. What passes over is alkaline. It was analyzed after being dried at 230°, and found composed of IHTTEn PRINCIPLF.S. 713 ur of lier- lie yellow 3d with an rberite, it rberite but If we heat in a gentle er taste of ;^e smell of ;llow colour •olour with- most of the » and wash- bitter taste. ;ohol. The wn crystals, •olour. But resume the ash. Lime- i the solution forms preci- ^aid loses its )rrosi^'e subli- , tartar emetic ite of bismuth Dra\;gc. Sul- low. Acetate after standing c and the pro- Q o-ives it a red ire°continue the )lution becomes . and insoluble dily soluble in It a little above sumes its yellow ts, swells, gives aves a charcoal water at 212°, and a yellowish , charry residue, is alkaline, found composed Carbon 6 1 "23 or 33 atoms Hydrogen 5'49 or 18 atoms Azote 4*03 or 1 atom Oxygen 29*25 or 12 atoms 24*75 or per cent. ()0'74 2-25 — — 5*52 1-75 — — 4-21) 1200 — — 29'45 7!' •". 100-00 40-75 100 The compound of berberite and oxide of silver consisted of Oxide of silver . . 25-98 or 14-5 ^ Berberite . . . 74-02 or 39 100-00 The number 39 does not correspond well with 40*75, the atomic weight determined by analysis, unless we suppose, that in the state in which it was analyzed it contained an atom of water. It was administered by M. Buchner to the extent of 10 grains, and found a powerful tonic. Berberite answers very well as a dye- stuff and gives a fixed yellow colour without any mordant. Chloride of tin improves the colour. When the cloth is previously impreg- nated with sulphate of copper, a beautiful greenish-yellow colour is obtained. With nutgalls the colour is yellowish-brown. 12. Lupinite. Cassola* has extracted from the beans of the lupinus albus, a peculiar bitter substance to which be has given the name of lupinite. The meal of these beans is treated with anhy- drous alcohol. The solution being evaporated to dryness, the lupinite remains. It has a green colour, is translucent, and may be melted. It is soluble in anhydrous alcohol and ether. Its taste is bitter. But it is not probable that it was obtained by Cassola free from an admix- ture of other vegetable substances. 13. Phloridzite. This is a name given by Dr Koninck, to ca bitter-tasted principle, which exists in the bark of the trunk and roots of the apple, pear, cherry, and plum-trees. f Its existence was first noticed by Professor Geiger of Heidelberg,^ but it was first obtained in a separate state, and its characters determined, by Dr Koninck. § The preparation of this substance is very simple. The fresh bark of the root of the apple-tree is boiled for two hours in a quantity of water sufficient to cover it. This water is decanted off, and the boiling repeated with a second portion, and this last decoction must be kept separate from the first. It commonly deposits in 24 hours, a considerable quantity of granular crystals of phloridzite, which, when dissolved in distilled water, and treated with animal charcoal, are rendered quite pure. We obtain an additional quantity by eva- porating the liquid down to J-tli. In this state of concentration, it deposits the whole phloridzite which it contains, when left at rest * Jour, de Chi. Med. x. 688. f Hence the name phloridzite, from ;, hark, and pi^a, root. \. Handhuch dcr I'harmacie, ii. 62. § Lieljig's Jour, der Piiarm. xv. 75 and 2.j8. n I; t !•' I 714 UITTER IMIINCM'LF.S. for a couple of dii\ h. Tho bark of apple-tree root, when treated in tliia way, yields about 3 per cent, of plilorid/itc. Hy anotiici- process we may ol)tiiiii about 5 per rent. It consists in dijrestinjj^ tlie/zWi bark of the root in weak alcoiiol, at about the temperature of 122°, The dii^^estion is contintied from H to 10 hours. The greater part of the alcohol is then distilled oil", and the residue set to crystallize. The first crystiils obtained in this way are whiter than those obtained by the first process. They arc to be purified in the same way as the others. Phloridzite thus obtained, has a dull white colour, with a shad«! of yellow, and is crystallized in silky needles. It may be also obtained in tables. Its taste is intensely bitter. Water at 72°, or lower, dissolves only the thousandth part of its weight of it. lint from Id" to 212°, it dissolves it in all proportion. It is very solu- ble in absolute alcohol, at the connnon temperature of the atmo- sphere ; but it is very little soluble in ether. It has no action on vegetable colours. Its specific gravity is 1*4208. When heated to 212", it loses all its water of crystallization ; but when dried in the ordinary temperature only, it retains 7 per cent, of that 'iquid. When the water is once driven off, it is not again absorbed, even in a moist atmos})liere. Phloridzite melts at 22{)°i, and boils at SoO^^. At 379°A- it begins to be decomposed, a small quantity of benzene acid being formed, some acetone, and a brown oil heavier than water. The concentrated acids dissolve it without decomposition, while it retains its water. 13ut wi 'mi anhydrous, it is strongly attacked by sulphuric acid, and forms a reddish brown solution. Nitric acid behaves in the same way while cold, but by heat it converts it com- pletely into oxalic acid. Muriatic acid converts it into a white insoluble substance which separates. When boiled with dilute sulphuric ncid for 8 or 10 hours, It is not converted into sugar. The; alkalies and concentrated acetic acid dissolve it without alteration. Chlorine, bromine, and iodine, act upon it with violence, produc- ing a brown resinous substance, insoluble in water, but soluble in alcohol. Much heat is evolved, and muriatic acid, hydrobromic acid, and hydrlodic acid, arc respectively given out. Persulphate of iron gives, with solution of phloridzite, a yellowish- brown precipitate, and perchloride of iron, a very dark-brown pre- cipitate. But tiio protosulphate of iron has no action. The same remark applies to the neutral metallic salts. Diacetate of lead throvvs down a copious wl ,((! precipitate, which becomes yellow when dry. Clilorite of lime {bleaching powder) gives it a light-yellow colour, which in a few days becomes brown, without occasioning any preci- pitate. Aqueous solution of cMorine throws down a yellow pi*eci- ])itate. Gelatine does not produce any alteration on its solutions. We have two analyses of phloridzite. The first by M. Chr. Petersen,* and tlie second by I)r Koniuck.t Hut they dilfer so * .loiu. (ler I'lianii, w. 17S. f l'-'"'- "v. -'(il. WnTKri PRINCII'LKS. 713 treated iu It consists t aUout tlic )iu H to 10 otV, and t\u; ill tliis* way ey are to be ith a shade nay be also iv at 7'2°, or of it. Ui't is very solu- of the atmo- nt) action on llization; but IS 7 per cent. Is not ag.ii" At 379H i<^ ,;c acid being vater. position, wbde ongly attacked n.° Nitric acid onverts it coni- t into a white hours, it is not ated acetic acid 'iolence, produc- •, but soluble i» ydrobrouiicacid, izite,aycllow;sh- dark-brown prc- tion. The same ate of lead throws irellow when dry. vht-yellow coloiu', 'sioning any preci- ■n a yellow preci- i on its solutions. ti,st by U. Chr. Hut they diiler so ■ iijia. XV. -^'ii- I'l'ti'mon, KnnliR'k 5(vH) 51*0 5-H2 5-0 3H-02 4:}-4 100' 00 100 much from eacli other, tliut it , scarcely possible that they can have operated upon the same substance in a state of j)tirity. I'he results are as follows : — (Jarbon Ilydronen Oxygen The first of these numbers corresponds with the following atomic constitution. 4 atoms carbon 2^ atiMus hydrogen 2 atoms oxygen while Dr Koninck's analysis gives us ;} atoms carbon 2 atoms hytlrogcn . 2 atoms oxygen = .3 ;z 0- 3125 = 2 5- 3125 — ■ 2-25 c= 0-25 — 2 4-r)0 A new analysis will be requisite to settle these di-icordant results. 14. Bitkr principle of variularia c/marn, or picrolichenitc. This substance was discovered in 1832, by M. Alms of Penzlin in Mech- Icnburg* in the variolaria amara, a lichen which grows in great abundance on the bark of the beet;li. His mode of obtaining it was this. It was digested iu cold alcoliol, till every thing soluble was taken up. The alcohol being distilled off, left a great deal of chlorophylle resin, and a light-green crystalline matter, amounting to about 8 per cent, of the lichen employed. This, when purified by weak potash, constitutes the bitter principle. It crystallizes in octahedron?, with a rhomboidal base, and is nol altered by exposure to the atmosphere. It has no smell, but a very intense bitter taste. Its specific gravity Is 1'17(J. It is a neutral substance, insoluble in cold W8ier, but slightly soluble in boiling water, and very soluble in alcohol, ? ad ether, and bisulphuret of carbon. When left under a glass aliTstr ulo of another vessel containing anmionia, it is gradually converted into a red resin, quite destitute of bitterness. Sulphuric acid forms with it a colourless solution, precipitated by water. Nitric acid has but little action. Muriatic acid and phosphoric acid are inert. Oil of turpentine, naphtha, and various fixed oils dissolve it. Carbonate of potash takes up a little of it, which is thrown down again by water. Potash ley forms with it a wine-red solution. It melts when heated a little above the fusing * .lour, ilcr I'liHi'inaiic. i, . Scillitite. Tliia ia the peculiar Huhstance to which the hulh of the nciltn mnritima, or 8(pnll, owes its mediciuiil ciualitioa. Its pro- jjcrties were iiivestijfated hy Vo^xel, 1812, who pointed out it.s peculiar nature, and rsian naphtha was analyzed by Blanchet and Sell, who ob- tained Carbon 83*90 Hydrogen . . . . 14*21 9811$ These numbers lead to the formula — I atom carbon 0*75 or per cent. 85*7 1 atom hydrogen 0*125 — — 14*3 0*875 100*0 Doubtless Persian naphtha is composed of an equal number of atoms of carbon and hydrogen, probably 12 atoms of each. • Edin. Trans, xiii. 118. f Ibid. p. 124. X Ann. der Pharm. vi. 309. V 1 U I !i 720 PRODUCTS OF DISTILLATION. SECTION II. — OF COAL NAPHTHA. From the experiments already made, there are strong reasons for concluding, that the naphtha obtained by distilling the petroleum from Trinidad, and the asphalt from the Dead Sea, is precisely similar to that procured by rectifying coal tar. It is probable also that the naphtha from Amiano is of the same nature.* Naphtha is limpid and colourless, like water. It has a bituminous smell, a specific gravity of 0*817 ; and Reichenbach supposed that it possesses the characters of oil of turpentine. It burns with a strong yellow flame, giving out much smoke. It is insoluble in water. Alcohol dissolves about Jth of its weight of it. Ether, petroleum, fixed oils, and volatile oils, com- bine with it in every proportion. It dissolves wax by the assistance of heat, and deposits a portion of it again as it cools. Caoutchouc swells in it to more than thirty times its original bulk, and becomes gelatinous and transparent, but scarcely dissolves. But by long boiling, a solution is effected. Saussure found that 1 volume of vapour of naphtha requires 14 volumes of oxygen gas for complete combustion, and there remain, after the combustion, 8 volumes of carbonic acid gas. Unvovdorboii, by cautiously rectifying naphtha, resolved it into various liquids, differing f.om each other in their boiling point. Blanchet and Sell found the boiling point of coal naphtha to vary from 302° to 356°. They analyzed a specimen, having a specific gravit) of 0*911, and boiling at 320°, and obtained Carbon 87*94 Hydrogen .... 907 97-Olt It doubtless contains oxygen, for it converts potassium into potasli with great rapidity. If we admit the loss to be oxygen, the con- stitution will be 39 atoms carbon = 29*25 or per cent. 87*97 24 atoms hydrogen = 3*00 — — 9*02 1 atom oxygen = 1*00 — — 3-01 33*25 100 This is very nearly 4x10 atoms carbon 3x8 atoms hydrogen 1 atom oxygen. Here we see the analogy between coal naphtha and the pctrolene of Houssingault, described in the next Section. Hess analyzed it a great many times with the same result. * This, however is somewhat doubtful, as ilc Saussure, by roctifjing Amiano naphtha three times, reduced its specific g^ravity to 07JH, wliich is considerably lower than the specific gravity of coal naphtha. f Ann. der Pliarni. vi. 311.'. PETROLENli;. 721 reasons for oleum from jely similar Iso that the bituminous pposed that irns with a Jth of its e oils, com- ic assistance Caoutchouc and becomes But by long a requires 14 there remain, solved it into joiling point. Lphtha to vary nng a specitic It m into potasli the con- ^•gen! i7-97 9-02 3-01 )0 he pctrolenc of l^ same r esult. roctifjing Amiano icli is' considerably There was always a deficiency, varying from 3 to 6 per cent. But when it was distilled along with water, the naphtha that came over was found composed of -^ Carbon 86*42 Hyd rogen 14-08 100-50* Obviously equal atoms of carbon and hydrogen. The substance containing oxygen is evidently the yellow oil which remains in the retort. SECTION III. — OF PETROLENE. This name has been given by M. Boussingaultf to a substance which he extracted from the bitumen of Bechelbronn, in the de- partment of the Bas Rhine. This bitumen is viscid, and has a very deep-brown colour. It is known in the neighbourhood under the name of sto7ie oil, and is employed as a substitute for grease for machinery. Alcohol of 0-817, when digested on it, assumes a brown colour, and the bitumen becomes much more consistent than before. It dissolves easily, and completely in ether. It loses no weight, though kept at the temperature of 212°. But when the heat is raised to 446°, drops of an oily liquid pass over, but very slowly. It is this oily matter to which Boussingault has given the name oi petrolene. He mixed together about 22 imperial gallons of water with from 12 to 1.5 pounds of the bitumen, and dis- tilled in an alembic. The oil that comes over is very liquid, but has a brown colour. It is to be dried over chloride of calcium, and then rectified in a retort. It is now pure. Petrolene, thus obtained, has a pale yellow colour, little taste, but a bitimiinous odour. Its specific gravity at 70° is 0-891. It remains liquid, though cooled down to 10*^^. I- stains paper like the volatile oils, and burns with a lively flame, giving out much smoke. It boils at 536°. Alcohol dissolves it in small quantity ; but it is much more soluble in ether. Boussingault subjected it to analysis, and obtained Carbon .... 87-04 Hydrogen . . . . 12-21 99-25 The specific gravity of the vapour of petrolene was found to be 9-415. Now, 87-04 carbon, and 12-21 hydrogen, approach the formula — 10 atoms carbon . , . 7-5 8 atoms hydrogen ... 1 8^ which represents the constitution of oil ol' turpentine, and several other volatile oils. And • Poggciulorf's Ann. dor Pliys. xxxvi. 4G4. f Ann. (Jo Cbiin. et do Phys. Ixiv. i41. 3 A s soft and clastic. But it undergoes decom- position before it can be melted. It burns like the resins, leaving a bulky charcoal. When pure, it leaves iiu residue after complete combustion. M. Boussingault analyzed asphaltene, and obtained Carbon 74-25 or 19 atoms = 14-25 or per cent. 74-51 Hydrogen 9-96 or 15 atoms = 1-875 — — 9-81 Oxygen 15-79 or 3 atoms =3 _ ~ 15-68 19-125 100 100-00 Now, 19: 15:: 20: 15-8. From this, it is likely that asphaltene is nothing else than petro- lene united with oxygen. On that supposition, the atomic weight would be 20. It would appear that the bitumen of Bechelbronn is a compound of j)etrolene and asphaltene. In the proportion of 1 atom petrolene = 17 or per cent. 14-53 5 atoms asphaltene = 100 — — 85-47' 117 100-00 * Ann. de Cliini. ot lie Phys. 'xiv. U8. ofl bill liul PVaFFIN. 723 (33 III 444 jtrolene is ny atoms as with alcoliol, ; alcohol dis- cting the al- !ohol, deprive isingault suc- tt at a heat of 3 continued at atter. To the t has given the by him, arc as iks with a con- :hen heated to lergoes decom- resins, leaving ! after complete ed cent. 74-51 __ 9-81 _- 15-68 100 else than petro- he atomic weight nn is a compound f 14-53 85-47' 100-00 SECTION V. — OF PAUAFFIN. This substance was didcovered by M. Reichenbach, of Blansko, in Moravia, and made known to the chemical public in 1830.* It exists in the tar obtained by the distillation of various substances, hoth animal and vegetable. But it is from vegetable tar, and es|)ecially from the tar of the beech tree, that we obtain it in greatest abundance, and with most facility. If we distil to dryness the tar obtained from the beech, three liquids will be found in the receiver, a light oil swimming on the top, below it an aqueous liquid having an acid taste, and a heavy oil at the bottom. This last liquid is to be distilled a second time. As soon as what comes over begins to ffct thick, and to deposit scales, the receiver must be changed. The heat is now raised till what comes over becomes black and thick. We find in the receiver an oil, containing numerous scales of paraffin. There are two ways in which this paraffin may be separated. The first method is to agitate the liquid in the receiver, with six or eight times its weight of alcohol of the specific gravity 0-837. After an interval of repose, a viscid mass subsides from the liquid. This matter is to be repeatedly washed with alcohol till it is trans- formed into small colourless scales. These scales are to be dissolved in absolute alcohol by the assistance of heat. On cooling the paraffin is deposited in small white scales and needles. To render it perfectly pure, it must be repeatedly dissolved in hot alcohol, and crystallized by cooling. This process, of course, is expensive. We must use a great deal of alcohol, and a considerable portion of the paraffin remains in solution. The second process is more economical. The heavy oil from the tar is distilled repeatedly. It is then mixed with strong sulphuric acid by small quantities at a time (ggth of its weight) till the mix- ture is quite black and liquid. Heat is evolved and sulphurous acid formed. The quantity of acid requisite, amounts to from ^^th to i the weight of the oily liquid. If the heat produced does not amount to 212°, we must raise the mixture to that temperature artificially. The mixture, after being thus heated, is to be left at rest for 12 hours or more, in a stove, whose temperature is not lower than 122°, that the paraffin may not become solid. At the end of that time, we find at the surface a liquid perfectly colourless. This liquid, which is a combination of paraffin, and a peculiar oil, is to be decanted off. Or, if we allow the whole to get cold, this uppermost liquid will congeal, and may be taken off under the form of a crust. Let it be broken, 'washed with water, and exposed to pressure between folds of blotting paper. The oil is absorbed by * Schweigger's Journal, lix. 436; Ixi. 273; mid Ixii. 129. It was discovered by Dr Cliristison, Professor of Materia Medica in tlie University of Edin- biirgli, about the same time that lleichenbacii was investigating its properties. He obtained it by distilling the petroleum of Rangoon ; and, in 1831, read u notice of it to the Royal Society of Edinburgh, under tlic name oi pchvUnc. ] . \ atmosphere. When heated to 110° it melts into a colourless, transparent oil. At a stilj iiigher tempera- ture it boils, and may be distilled over without alteration. When heated over a lamp in a platinum spoon it melts, and then catche-; fire, and burns with a white flame without smoke, and leaves no residue. Its specific gravity is 0'870. It has very little tendency to combine with other bodies. Hence the name paraffin (parum offinis) by which M. Reichenbach has distinguished it. Chlorine, whether dissolved in water or in the gaseous state, has no action on it. Nor is it acted on or altered by sulphuric, muriatic, nitric, acetic, oxalic, or tartaric acids, nor by solutions of potash, ammonia, lime, barytes, strontiaii, the alkaline carbonates, hydrate of lime, nor by potassium, when even in a state of fusion. Red oxide of lead and binoxide of manganese, are equally without action on it. When it is melted with sulphur, phosphorus, or seleniiun, it dissolves only a minute quantity of these bodies, and undergoes no sensible alteration in its qualities. It cannot be combined by fusion with camphor, napthalin, benzoin, nor pitch. But it may be united by heat with stearin, cetin, bees' wax, and common rosin. Melted hoirs' lard and mutton suet com- bine with it, but separate on cooling. Olive oil, while cold, is a bad solvent of paraffin ; but it d' olves it with facility when hot. The same remark applies to oil of almonds. But oil of turpentine and coal naphtha dissolve it with facility, without the assistance of heat. Ether is its best solvent. 100 parts of that liquid dissolve 140 of paraffin at the temperature of 77°. When the liquid is cooled a little below that ])oint the whole becomes solid, in consequence of tlic crystallizing of the paraffin. Cold alcoliol dissolves very little of it. 100 parts of boiling alcohol dissolve 3*45 parts of paraffin, but the paraffin crystallizes when the liquid cools. Paraffin has no action on vegetable blues.* * Poirgondorf'!- Annaleii, xxiv. 173. KUPION. 725 tc scales by heat. y flexible, per. . from the td, and an 3 paraffin, anew with be not en- ; aciil, and erature not stance, of a 3 nearly the iadily unite, ilatile at the d to 110° it ler tempera- ion. When then catches .nd leaves no dies. Hence :;henbach has ter or in the , or altered by acids, nor by 1, the alkaline 3ven in a state aniianese, are with sulphur, ,te quantity^ of ill its qualities, halin, benzoin, •in, cetin, bees' itton suet com- e cold, is a bad rben hot. The turpentine and le assistance of nid dissolve 140 liquid is cooled a consequence ot ssolves very Uttlo parts of paraffin, Paraffin has no As paraffin, so far as wo know, does not enter into any definite compounds with other substances, we have no means of dcternilnin;Lr its atomic weight ; but M. Juhis Gay-Lussac has subjected it to analysis by means of oxide of copper. And found its constituents to be Carbon 84*04 or 1 atom = 0*7.5 or per cent. 85*71 Hydrogen 13*87 or 1 atom = 0*125 _ _ 14*29 97*91* 0-875 100*00 It is, therefore, another substance belonging to the numerous tribe of carbo-hydrofjcn ; but how many atoms of each constituent enters into its composition, we do not know. As it is easily distilled ovor, there would be no great difficulty In detorminlnir the specific gravity of its vapour. This would furnish data for calculating its atomic constitution. A substance has lately been discovered in Moldavia, in consider- able masses, which has been distinguished by the name oi fossil tvax of Moldavia. M. Magnus has subjected this wax to analysis, and found that it consisted, in a great measure, of pai-affin.f M. Laurent has shown that paraffin may be obtained also by dis- tilling the shale, which is so abundant in the coal-beds of Great Britain.^ If paraffin could be obtained at a sufficiently cheap rate, it might be substituted for wax in many cases.§ SECTION VI. — OF EUI'ION.II This substance was also discovered by Relchenbach, and its characters described by him in 1 83»1 . It Is obtained by distilling, in a retort, the tar which is procured by decomposing animal muscle, bone, leather, or horn, by distilln- tlon in the dry way. But it may be obtained also from vegetable tar and from coal tar. If 8 parts of tar be ))ut into the retort, 5 * Porr!j;ondorr9 Annalen, xxiv. ISO. ■f Ann. de Cliim. et de Pliys. Iv. t2]8. Sec an account of it among the fixed solid oils, page 448. X Ibid. liv. .'392. § A substance sent to Dr Troinmsdnrf liy M. Fikentscbor of Rinlwifz. and dis- covered in a bid of peat, a|)pcars, from the exi)eriments of T'roinnisdorf. to resemble paraffin very closely in its properties, tboutrb it diilors in its composition. When purified by solution in alcobol and eva|)oration, it was in soft white plates, Jiaving a fatty initio. The only difierence observable between the properties of this substance ami tho-jo of ])araRin is, that it does not melt till heated to 'J 19", while puratlin melts at 1 IM". It was aiudyzcd l)y Trominsdorf, junior, and found composed of Carbon 90'91 or 2 atoms = 1'5 makin;;- ])er cent. 02 .'5 Hvdroijeu 7"5G or 1 atom = 0'125 — — 77 1 -(i-J.J 98-47 See .\nn. <1(t Pharinacie. xxi. 120. II roirgendorf's Annalen, xxiv. I7;J, lOOO I >.i i> i!\ •I : ^ i.i 'H i J , ':] ■■ i. ^ ' :«■; ^i ij ii ; V,- S- a 1 '■ 1 720 PRODUCTS OF DISTILLATION. ! i I ! are to be distilled off. These 5 parts are again put into a retort and 3 parts of them distilled ofF. This new liquid is to bo mixed with sulphuric tcid (a little at a time), in the proportion of 10 ounces avoirdupois, of acid, for every imperial gallon of tar em- ployed ; and the mixture is to be well agitated. We obtain a red- coloured liquid, together with a subtile transparent yellow liquid. This last liquid is separated from the other, and mixed in a retort with its own weight of sulphuric acid, and ^[ths of it is distilled off. What comes over is a colourless liquid, which is washed with potash ley ; and, after digesting for some time, the oil is separated, mixed with half its weight of sulphuric acid, and distilled anew. The liquid, which conies over, is to be washed with potash ley, and then decanted off. It is now mixed with pure water, and distilled very slowly till ^ths have passed over into the receiver. What re- mains is a mixture of paraffin and eupion. The distilled portion is left under a vacuum for 24 hours. It is then mixed with a few grains of potassium, and raised to the boiling temperature. This occasions the separation of reddish-brown flocks. The process is repeated till the reddish-brown flocks cease to form, and the potas- sium retains its metallic lustre. The liquid, being decanted off, is eupion. Reichenbach has found more lately,* that eupion may be obtained much purer by distilling rapeseed oil. This oil is distilled in an iron retort with a moderate fire, so that the oil may not pass over. The first and the last portions distilled over are sepiirated from the rest, because they contain foreign matter. The middle jjortion is liquid, and has a specific gravity of 0*8 G. When distilled again it is as liquid as water, and has a specific gravity of 0*83. Its colour is yellow. When again rectified its specific gravity becomes 0*77. If it be now mixed witl\ concentrated sulphuric acid, and distilled again, washed with potdsh ley, and finally purified with sulphuric acid, as specified above, its specific gravity is reduced to 0*70. Let it be now distilled in a temperature of 122°, and again rectified in a temperature of 97°, and finally distilled at 97°. From chloride of calcium, we obtain it pure. It is a colourless liquid like water, which does not become solid, though cooled down to — 4°. It has no taste, but a smell like that of blossoms ; is not altered by exposure to the air ; is a non-con- ductor of electricity. It feels neither fatty nor harsh, and has no effect upon litmus or turmeric paper. Its power of dispersing light is exceedingly small. It boils at 11G°|' and if it be quite pure it may be distilled over without leaving any residue whatever. When dropt upon water, it does not, like oil, spread on the surface. W^hile cold it does not tiike fire from the flame of a candle; but when boiled over a lamp in a platinum spoon, it may be made to burn with a lively flame without giving out any smoke. Its specific gravity is 0*(J55. When impure eupion is heated from G(i° to 33G°, its volume increases about a fifth part. • Jour, fiir Pract. Cli. L. 377. a| e| III oj fll 01 EUPION. 727 a retort bo mixed ion of 10 if tar em- :ain a red- low liquid, in a retort istilled off. ished with separated, died anew, sli ley, and ,nd distilled What re- lied portion L with a few ture. This le process is d the potas- janted off, is r be obtained stilled in an ot pass over. ited from the le portion is illed again it Its colour leconies 0*77. and distilled ith sulphuric to 0-70. Let in rectified in )ni chloride of become solid, smell like that is a non-'3on- ih, and has no ispersing light e quite pure it atever. When n the surface. a candle; hut [lay be made to iC, j)ion is heated part. It is quite insoluble in water, absolute alcohol dissolves it in all proportions, liut it is very little soluble in alcohol of specific gravity 0-82. When we add to the solution of anhydrous alcohol, alcohol containing water, the eupion separates in unctuous drops. It unites in all proportions with ether, and with most of the volatile oils. Acetic ether dissolves about the tliird of its weight of eupion. Kisulphuret of carbon, oil of turpentine, naphtha, olive oil, and oil of almonds may be mixed with it readily, even while cold. Eupion dissolves readily chlorine at the conunon temperature of the atmosphere, and still more easily bromine. Ihit when tlie solution is heated, these bodies separate without occasioning any alteration. Iodine dissolves in it cold, and still more readily hot, and crystallizes in part as the solution cools, riiosplii rus, sulphur, and selenium are not dissolved, while the eupion is cold, bu readily when that liquid is heated. When the solution cools, the whole of the sulphur and phosphorus and the greater part of the selenium precipitates. Naphthaline, camphor, stearin, cetin, cholesterin, paraffin, and balsam of copaiva, are soluble in cold eupion, and still nu)re soluble when that liquid is hot. Tallow dissolves in it at the temperature of 77° ; but at (38° the liquid becomes muddy, probably, because the stearin precipitates while the olein remains in solution in the eupion. liees' wax is completely dissolved by hot eupion, but when the liquid cools, the greater part of it precipitates. Kosin dissolves only partially when the eupion is cold ; but completely by the assist- ance of a boiling heat. Benjoin, anime, copal, and lac, dissolve only partially, even when assisted by ebullition. When the liquid cools, these substances are again deposited either totally or partially. Caoutchouc swells enormously in eupion, yet it does not dissolve at the temperature of 212°; but the solution is complete when the eupion is boiled. The solution does not become dry by simple ex- posure to the at.nosphere. Hut when spread iq)on a plate of glass and put in a stove, it becomes gradually so coliosive, that it can be drawn out into threads and becomes at last dry. Concentrated nitric acid, concentrated sulphuric acid, muriatic, acetic, oxalic, tartaric, succinic and citric acids have no action on eui)ion. Neither is it acted on by potassium, hydrate of potash, hydrate of lime ; nor by solutions of potash, lime, barytes, strontian or ammonia ; nor by the alkaline carbonates, the red oxide of lead, the red oxide of mercury, the binoxide of manganese, the black oxide of copper, or the bichromate of potash. Such are the properties of eupion, so far as they have been in- vestigated. It was named by lieichenbach, from the Greek words iu (bene) and -jiuv {fat) ; in con8e(pience of its analogy to fatty matters. M. Laurent analyzed eupion, which he got from M. Boy veau, but it is obvious that it was not pure, for he says that its boding point was 330°. Its constituents were \ii ''m ' t <• I Is 728 pnonucTS oi distillation. Ciirl)on If droijLMi 85-;i or 1)*5 atoms ir>'l or 10 atoms l()()-4* Hesse nnulyxcd a specimen prepared by distiUing hemp oil, and found it compoisod of Ciirbon . . 83*37 or 8*5 atoms Hydrogon . . Ui- 37 or 10 atoms y9-74t New rosoarchcs will be necessary to settle the constituents of enpion with precision. SECTION VII. — OF CUKOSOTE. Thi.! substance was discovered by M. lioicbonbach, and the dis- covery was announced by bim at the nicotin'j; of the German Scientific Association at Vienna, in 18324 In 1833 M. lleiciien- bach himself published a detailed account of the process by which he procured it.§ The same year it was analyzed (thoutih not in a state of perfect i)urity), by M. Ettliiinf, in the laboratoiy of Profes- sor Liebig.ll It exists in impure pyrolignous acid, and in the tar obtained by the distillation of wood. As the tar contains it in the '2, Fhvs. liii. 325. a aj aJ aj 01 wl CUEOSOTK. ''20 mp oil, and nts of cupion , and tbe dis- the Gorman M. lleU-hon- icss by '.vlucli oiy ot ri-otes- av obtained by 11 the «ii-oatest hat sul)stancc. anains lias tlie livtion too soon i is apt to be Iqiiid empyreu- iwbicb it istbc ftcr t\ie process rhicU last liquid must take care the acidulous the oil is to be o distillations is s. At a certain iTi'dcr the '.vater. ^bicb swims over cupion and sonic Hence the od hrown away, ccomcs brown ni d, caustic, and at 'harmacic, xxiii. 247- 1-23, ami xxix. 0-- Mie atmosphere. An "I'cat measure do- .t; lole to assume a in the open vessel once hitter ai 1 sweet. Tliis oil U lu'utfd, and carbonate of potash is added to it as lonir us carbonic acid is disengaged. It is then deciiiited ott' in order to separate a ([imntity of acetate of potash, whieli has formed, and distilled a .rain in n ^ha*^ retort. The dis- tillation is not contiinied till tlie matter in the retort becomes (piitc dry : and the first products, whicji swim on the water arc throw n away. The oil is now dissolved in a solution of caustic potash havinj; u spec' tic gravity of 1*1 '2. Much heat is evolved : a portion of eupion mixed with other oils does not dissolve; ; but swinu on tiie surface. It must be removed. The alkaline rupiid is nr.w poured into an open evaporatijig vessel and raised to tlic ' filing tempeniture. It al)sorbs rapidly, a great deal of oxvgci oxidable matter contained in the liiii composed by this {ibsorption. This isi browi colour. The Tupuil is now allow and dilute sulphuric acid is added to it iili the oil separates from the alkali. This oil is mixed with water containing a little caustic potash and distilled. As water dissolves a little creosote, we nmst in order to prevent too great a loss, i)our back into the retort, from time to time, the water that passes over into the receiver. Though the water is kept boiling briskly, the creosote passes over slowly, be- cause its tension, at '212°, is very feeble. After a certain time, though a good deal of oil still remains in the retort, yet very little passes over tliounh we augment the tire. It is time when this happens to stop the distillation. The residue contains picninar. a small quantity of picamar (Combined with potash, sulphate of potash, a little acetate of potash and a brown coloured matter. The oil, distilled over, is separated from the water which has passed over along with it. We dissolve it a second time in a solu- tion of caustic potash of the specitic gravity 1*12. There remains a notable quantity of light oil, which does not dissolve. It consists as before of eupion nuxed with several oily bodies, and is of course separated. The solution is raised to the boiling temperature in an open vessel and alluwed to cool slowly. Its colour again becomes brown, though in an inferior degree. Sulphuric acid is added as before, and a slight excess is requisite that the oil itself may absorb a small quantity. The oil is then washed repc itedly with water till all the acid is removed. This oil is again mixed with water to which no potash is now added ; but a little phosi)horic acid to remove a small portion of ammonia, which the oil still retains. The distilled oil is dissolved a third time in caustic potash. No oily residue now remains, and the solution does not become brown when heated and cooled ; but acquires merely a slight reddish tint. In this state creosote is not quite pure, though it may be em-, ployed for medicinal purposes. To purify it couqdetely, we should distil it with water without any addition, and then rectify the pro- duct of this distillation which is hydrated. There passes first into f :*;-» ' 'M < 1 \ ^^.^ IMAGE EVALUATION TEST TARGET (MT-3) 1.0 1.1 lis 150 121 |2.5 m ^ 1^ ^ U& 12.0 «Uu IL25 i 1.4 I m HiotDgraphic Sciences Corporation 23 WEST MAIN STREET WEBSTER, N.Y. 14S80 (716)872-4503 \ o\ '^ WAJ^ I ' I 730 PRODUCTS OF DISTILLATION. the receiver a good deal of water. Its amount diminishes gradually, and at last it ceases to come over altogether, while at the same time a little creosote comes over. These first products must be rejected. We must not begin to collect the creosote till it comes over alone, and till the boiling point rises to 397°. If we rectify the product thus obtained, and cause the vapours to pass over chloride of calcium, we will obtain creosote still more completely deprived of water. Such was the original process of M. Reichenbach. It has been recently a good deal simplified by M. Hubschmann.* He takes the tar formed during the manufacture of pyrolignous acid, puts it into a large retort along with some grains of sand, in order to increase the number of bubbles that are formed during boiling, and thus diminish its violence. What comes over first, consisting of eupion, acetic acid, &c., is laid aside, but whenever a liquid begins to appear which falls drop by drop into the receiver, and falls to the bottom of the water, the receiver is changed and the product collected. The distillation is continued till the mass begins to froth. The product of the distillation is poured into a vessel with about double its vo- lume of water, to which as much sulphuric acid has been added, as will enable the liquid containing the creosote to swim on the surface. The liquid is slowly raised to the boiling temperature, and kept boiling for some minutes. The whole is now allowed to cool. The colour- less liquid which is undermost is abstracted, and the brown oil swim- ing on the surface rectified in a retort. What comes over is to be treated again as before, with dilute sulphuric acid. It again assumes a brown colour. But after another rectification, and being freed from eupion, it has a straw-yellow colour. To separate the eupion, the product should be dissolved in a solu- tion of caustic potash, according to Reichenbach's method above described. The light oil which swims is separated, the potash ley heated, and after it has been allowed to cool, the potash is saturated with sulphuric acid, which causes the creosote, of a brown colour, to swim on the surface. This creosote being separated, agitated with water containing some potash, and then distilled in a fresh retort, is almost colourless. But as it becomes brown on exposure to the air, Hubschmann recommends keeping it for some weeks in a cellar in an open bottle, mixing with it a little potash. Being now rectified it may be considered as nearly pure. Creosote thus obtained, is a colourless transparent liquid, which refracts light very powerfully. Its odour is penetrating, and disagree- able, somewhat analogous to that of smoked meat. Its taste is hot and very caustic. Its specific gravity is 1*037, at the temperature of 68°. It boils at 397°^, and does not congeal when cooled down to — 16°^. It burns with flame, emitting at the same time a great deal of smoke. It is a nonconductor of electricity. With water, at the ordinary temperature of the atmosphere, it forms two combinations : one, a solution of 1 '25 parts of creosote in * Ann. de Cliiiii. et ver is to be o-ain assumes %eing freed vedin asolu- lethod above he potash ley h is saturated ,wn colour, to agitated with fresh retort, Lposure to the eks in a cellar T now rectified f liquid, which ,anddisagree- its taste is hot e temperature in cooled down le time a great atmosphere, it s of creosote in 100 of water, the other, a solution of 10 parts water in 100 of creosote. The aqueous solutions of creosote are neutral. For they have not the property of neutralizing either acids or alkalies. Concentrated creosote dissolves black oxide of copper, and assumes a chocolate colour. It reduces red oxide of mercury at a boiling temperature, and is at the same time changed into a resin, which contains no creosote. Nitric acid attacks creosote with energy, while red fumes are emitted. It is coloured by chlorine, bromme, iodine, phosphorus, and sulphur. When it absorbs chlorine it assumes at first a pale- yellow colour, then acquires a deep reddish-yellow tint, while a resin, similar to that from red oxide of mercury, is formed. When potassium is thrown into creosote, it disappears with the evolution of a gas, and the formation of potash, which combines with, and thickens the creosote. When we distil this mixture, we obtain a portion of the creosote unaltered. A small quantity of concentrated sulphuric acid, gi\'«3 creosote a red colour ; a larger quantity blackens and thickens it. The sulphuric acid is decomposed, and sulphur disengaged. Of all the organic acids, it is the acetic which is the best solvent of creosote. These two bodies may be mixed in any proportion. Creosote forms, without the assistance of heat, two different com- binations with potash : the one is an anhydrous liquid having an oily consistence, the other, a hydrous solid, crystallized in scales, having a white colour, and a pearly lustre. All the acids, even the carbonic, separate the creosote unaltered from these combinations. Soda acts precisely in the same way as potash. Creosote has considerable affinity for hydrates of barytes and lime, forming with them compounds of a dirty white-colour, soluble in water, and which, when dry, constitute a pale rose-coloured powder. Ammonia dissolves creosote without the assistance of heat. This alkali is usually combined with creosote, and is separated from it with difficulty. Creosote dissolves a great many salts ; some cold, others with the assistance of heat. Some are reduced ; but the greater number separate in crystals when the solution cools. As examples may be mentioned, acetates of potash, soda, ammonia, lead, and zinc, and chlorides of calcium and tin. It reduces the acetate and nitrate of silver. Alcohol, ether, bisulphuret of carbon, eupion, naphtha, and acetic ether, may be mixed in all proportions with creosote. Paraffin has very little tendency to combine with creosote. It does not dissolve in it unless the creosote contains eupion, and the quantity dissolved is proportional to the quantity of eupion present. Of all organic bodies, the resins and colouring matters dissolve best in creosote. It forms, without the assistance of heat, a reddish- yellow solution with cochineal, a deep-red solution with dragon's blood, a pale-yellow with red saunders, a purple with archil, a yellow with madder, and a golden-yellow with saffron. When placed in I n vrl 732 PRODUCTS OF DISTILLATION. I- contact with indigo, and assisted by lieat, it dissolves its colouring matter, which is precipitated when we add alcohol and water. It dissolves caoutchouc with great difficulty, when assisted by a boiling temperature; very different in this respect from eupion, which attacks that body with such facility. When creosote is placed in contact with albumen, it coiigulates it immediately. If, into a dilute aqueous solution of albumen, we add a single drop of creosote, white pellicles of coagulated albumen im- mediately make their appearance. When fresh meat is put into an aqueous solution of creosote, and after remaining half an hour is taken out again, we may expose it to the heat of the sun without any risk of its putrefying. It becomes hard in about eight days, assumes an agreeable odour of good smoked meat, and acquires a reddish-brown colour. Fish may be preserved by the same means. Now, since pyrolignous acid and tar water produce the same effect, there can be no doubt that creosote is the antiputrid principle of these bodies, as well as of smoke.* Creosote coagulates the albumen of the blood instantly, when the two liquids are concentrated ; gradually and slowly if one or other of them be mixed with water. Fibrin is not acted on by this substance. When a drop of creosote is applied to the tongue it occasions a violent pain. When concentrated creosote is applied to the skin it destroys the epidermis. Insects or fishes die speedily in an aque- ous solution of creosote. Plants die also when watered with this solution. It may replace with advantage, tar, pyrolignous acid, animal oil of Dippel, and empyreumatic water in the practice of medicine. Of late years, it has been employed successfully, both on the con- tinent and in this country, as a cur 3 ''^^ toothache occasioned by a carious tooth.f In Germany it is s o have been employed with effect, as a cure for hemorrhages, u. ;v,-ri, and even cancers. But the trials made of it in these diseases in Great Britain have not been successful. Indeed M. Hubschmaun makes the same remark with regard to the use of creo«''te as a medicine in Germany. J The same observation has been made b) the medical men who tried it in Paris. When given in too large doses it acts as a violent poison. Creosote was analyzed by M. Ettling. The specimen examined had been prepared by Reichenbach, who had not been able to free it completely from water. He obtained, as the mean of two analyses, * It is from this property that Reichenbach imposed the name creosote upon this substance. It is derived i'rora n^mt, flesh, and tuX,*!*, to save. The ttTiii creaso^e would, however, have been more contbrmable to this etymology than creo£o/c. + In Glasgow it was prepared by Messrs Turnbull and Company ; who havo long supplied this country with excellent acetic acid from wood, and with pyroxylic spirit. I Ann, de Chim. et de Phys. Ivii. 108. colouring ater. listed by a ,m eupion, jagulates it len, we add Ibumen im- •eosote, and ly expose it It becomes )ur of good Fish may lignous acid } doubt that s well as of tly, when the one or other i on by this it occasions a to the skin it y in an aque- ired with this id, animal oil of medicine. 1 on the con- casioned by a iniployed with ancers. But have not been 3 remark with r.X The same 10 tried it in (lent poison, aen examined been able to mean of two ne creosote upon 2ve. The term jgy than creosote. I)any ; who hayo lid with pyroxyhc Carbon Hydrogen Oxygen PICAMAIIK. 75*06 or 6 atoms = 4*5 or per cent. 75*8 1 7-78 or 3Jt atoms = 0-4375 7*38 17-16 or r atom = 1-0 16-81 733 100-00* 5-9375 100-00 But no conclusion can be drawn from these numbers, as we are ignorant of the atomic weight of creosote ; and do not know how- much water was present in the specimen subjected to analysis, by M. Ettling. The carbolic acid of Runge, appears to be nothing else than an impure creosote. ' SECTION VIM. — OF AMPELIN. This substance was prepared by M. LauVent, from the oil of bituminous slate, which boils between 392° and 536°. t This oil was agitated repeatedly with concentrated sulphuric acid, and then mixed with a 15th or 20th of its bulk of caustic potash dis- solved in water. Being left at rest for 24 hours, it separates into two layers, the undermost of which is more bulky than that of the potash liquid employed. This inferior layer is separated, and shaken with dilute sulphuric acid, which separates an oil, that swims upon the surface. This oil is drawn off by a sucker, introduced into a flask, and agitated with ten tunes its bulk of water. The ampelin dis- solves, and the small portion of oil remaining is thrown away. A few drops of sulphuric acid causes the ampelin to separate and swim on the surface. It is an oily-looking liquid, soluble in all proportions in water. If we dilute the solution with 40 or 50 times its weight of water, it acts with reagents in the following singular manner : — Some drops of sulphuric or nitric acid cause the ampelin to separate. Potash and ammonia render the liquid muddy, but when heated it becomes transparent. Carbonate of ammonia renders the solution muddy. Carbonates of potash and soda act in the same way, but heat restores the transparency of the liquid. Salammonica, chloride of sodium, and phosphate of soda, separate the ampelin. When sal ammonica or common salt is added to a solution of ampelin in potash or soda, the ampeline is separated. Nitric acid attacks ampelin violently at a boiling heat, and trans- forms it into a viscid insoluble substance. Some oxalic acid is formed. When ampelin is distilled, it undergoes decomposition, water and oil pass over, and much charcoal remains in the retort. SECTION IX. — OF PICAMARE. This substance was also obtained by M. Reichenbach, from the * Annalen der Pharmacie, vi. 208. f Anil, de Chim. ct de Phys, Ixiv. 32G. m ^ m 734 PRODUCTS OF DISTILLATION. I 5 tar of wood.* It may be obtained by the following process : — Wood tar is distilled and the products kept separate. Those pro- ducts which have a specific gravity between 1*080 and 1*095, are poured into eight times their weight of a solution of caustic potash, of the specific gravity 1*15. The two liquids are mixed as rapidly as possible, and then left in a state of rest. There is forifled at the surface, a layer of impure eupion containing paraffin. The liquid then becomes transparent, and in 24 hours is filled with shining crystals, in needles or plates. These crystals are dried by pressure between folds of blotting paper. They are then dissolved repeat- • edly in a boiling solution of potash, till the mother waters become colourless, and the crystals assume the colour of nankin. They are then decomposed by diluted phosphoric acid. The potash com- bines with the acid, and a limpid, brownish oil separates. This oil is distilled two or three times successively, with water acidulated with a little phosphoric acid. Finally it is cautiously distilled without any addition. In this state it constitutes picamare. It is a limpid transparent liquid, almost colourless, and having the consistence of a thick oil. It has an oily feel. Its smell is weak, but peculiar, and not disagreeable. It has an unsupportably bitter taste, at first giving an impression of heat, and then of cold, somewhat like oil of peppermint.f Its specific gravity is 1*10, at the temperature of 68®. Oxygen has no action on it at the ordinary temperature of the atmosphere. It brings red lead to a lower degree of oxidizement. It reduces the red oxide of mercury. Chlorine, bromine, and iodine attack it and alter it. It dissolves without alteration in sulphuric acid, and decomposition does not take place till the mixture is heated to 302°. Nitric acid destroys it. It dissolves readily in- acetic acid. M. Reichenbach is of opinion, that the bitterness of common pyrolignous acid is owing to the presence of picamare. With potash it forms a crystalline compound, which is almost in- soluble in alcohol. Dilute alcohol, when assisted by heat, dissolves a considerable quantity of these crystals, which separate in shining white crystals when the solution cools. When these crystals are not perfectly pure, they assume, by degrees, a brown or blue colour; when very impure, they acquire almost as deep a blue colour as indigo. In these crystals the potash is not neutralized, but retains its alkaline characters. Lime, soda, barytes, and am- monia form also combinations with picamare. It dissolves in all proportions in alcohol, ether, acetic ether, py- roxylic spirit, and creosote. It does not dissolve paraffiin, asphalt, nor amber. Caoutchouc is dissolved by it with the assistance of heat, but precipitates again when the solution cools. • Schweiarger's Jour. Ixvii. Jour de Pharmacle, xx. 362. f The name given by Reichenbach, is derived from this taste. In pice amarum, or the bitter principle in pitch. CAPNOMORB. 730 ocess : — hose pro- •095, are ic potash, IS rapidly qed at the rhe liquid ;h shining y pressure ed repeat- rs become in. They otash com- , This oil ulated with ed without Bind having [ts smell is supportably hen of cold, ature of the oxidizement. It dissolves ion does not Lcid destroys hs of opinion, wing to the is almost in- 3at, dissolves fte in shining crystals are [own or blue ]deep a blue t neutralized, ytes, and am- Itic ether, py- Piffiin, asphalt, assistance of 362. Ijn pice amarum, No attempts have been made to determine the constituents of picamare, by subjecting it to an ultimate analysis. SECTION X. — OF PITTACALL. This remarkable substance, which also constitutes an ingredient in wood tar, was described and named by M. Reichenbach about the same time that he gave an account of picamare. But there is little doubt that it is the same as a substance of a violet-blue colour, extracted in 1827 from coal tar by MM. Barthe and Laurent. If to an alcoholic solution of impure picamare, or of oil of tar deprived of its acid, we add some drops of barytes water, the liquid immediately assumes a fine blue colour, which, m about five minutes, passes into indigo blue. This phenomenon is owing to the presence o( pittacall in the solution. When this substance is precipitated in flocks from its solution, or when it is obtained by evaporation, it constitutes a dark blue, solid, brittle substance, like indigo. Like that pigment, when rub- bed, it assumes a copper colour, passing, according to its degree of purity, into golden or brass yellow. The golden lustre predomi- nates so much, that we cannot obtain pittacall free from it; and all substances over which it is spread appear as if they were gilded.* Pittacall is without smell, is tasteless, and not volatile. At a high temperature it is charred, without giving out the odour of am- monia. It is insoluble in water ; but is suspended in that liquid in a state of tenuity, so great, that it passes through filters and gives a blue colour to the liquid. It is not dtered by exposure to air or light. It dissolves in diluted sulphuric acid, and in muriatic acid, without the assistance of heat. Nitric acid decomposes it. Acetic acid dissolves it in great abundance ; the acid solution is aurora-red ; but it resumes its blue colour when an excess of alkalies added to the liquid. According to Reichenbach, it is a reagent for detect- ing acids and alkalies still more delicate than litmus. It is insoluble in alcohol, ether, and eupion. With acetate of lead, protochloride of tin, ammoniasulphate of copper, acetate of alumina, it strikes a fine blue colour, with a tint of violet. No doubt pittacall, if it could be procured at a suflficiently cheap rate, might be employed as a pigment. SECTION XI. — OF CAPNOMORE. This substance was discovered by Reichenbach, still more lately than the preceding five, and was so named by him (from xamog, smoke, and /mi^u, a part), because it exists in the smoke of organic bodies.f * Hence the name pittacall, from trirrx, pitch, and KaXkei, beautiful. So that the name signifies, literally, beautiful pitch. t Jour, de Chim. Medic, i. 195, and Records of General Science, ii. 79. Jour, de Pharmacic, xxi. 245. r I t ■Om 736 PnODUCTS OF WI8TILLATIOK. I i t ; ' It occurs along with creosote, picamarc, and pittacall, in the heavy oil of tar. On digesting that oil, deprived of acetic acid, by carbonate of potash, with a solution of potash, of the specific gravity 1*20, we obtain a solution. What does not dissolve after a second digestion with potash, may be thrown away. The alkaline liquor is put on the fire in an open vessel, heated slowlV) and allowed to boil for a short time. It is then allowed to cool slowly, and decom- posed by dilute sulphuric acid added in slight excess. By this ad- dition, a great quantity of dark-brown oil is disengaged. It is put into a retort along with a little potash, to . render it alkaline, and distilled, but not to dryness. The product of the distillation is a transparent pale oil. It is dissolved in a solution of potash, of the specific gravity, 1*16, and what does not dissolve is thrown away. It is heated, as before, to the boiling point, allowed to cool, mixed with dilute sulphuric acid, to separate the oil; saturated with potash, and distilled anew. These processes are repeated several times successively, diminishing every time the concentration of the potash solution to 1'12. 1*08, 1*05. When the oil is sufficiently pure, it dissolves without residue in sulphuric acid, in which eupion is insoluble. It is mixed with water, allowed to cool, saturated with ammonia, and distilled in a retort. The first portions are rejected ; then water comes over, and at last the capnomore, in the form of an oil. When pure, capnomore is a transparent colourless fluid, having the smell of rum or of punch. At first it appears to have no taste, but it gradually becomes acrid. It refracts light almost as power- fully as creosote. Its specific gravity, at 68°, is 0-'J775. It boils at 365*', under a pressure of 28*25 inches. It does not congeal at — 6°. It may be completely distilled over, without leaving any residue. It is a non- conductor of electricity. It is insoluble in water and in solution of potash, but dissolves in alcohol, ether, and eupion. It has the property of dissolving caoutchouc, especially when heated, and is the only ingredient in tar that does so. According to Reichenbach, the presence of capnomore in coal naphtha, is the cause of the solvent action of that liquid on caoutchouc. But this opinion could not be adopted, unless it could be shown, that capnomore is likewise an ingredient in oil of turpentine. With the vegetable bases it acts as an acid, and with sulphuric acid and the salts, as a base. It does not unite with the other bases. A combination, indeed, seems to take place, but it is de- composed by water. Capnomore is distinguished from creosote and picamare by its taste, its insolubility in the alkalies, and in acetic acid, and by the facility with which it dissolves caoutchouc. It differs from eupion by its specific gravity and boiling point, by the smoke which it emits when burning, by its solubility in sulphuric acid, its de- composition by nitric acid, its solubility in carbozotic acid, and its capacity of combining with the vegetable bases. CBDRinET. 737 , in the acid, by J gravity a second lie liquor lowed to d decom- ^ this ad- it is put aline, and ition is a sh, of the jwn away, ool, mixed [•ated with ted several tion of the residue in with water, in a retort. and at last uid, having ive no taste, pt as power- jS", under a it may he It is a non- No attempts have hitherto been made to subject capnomore to an ultimate analysis. Tlio characters above stated are sufficient to show, that carbon and hydrogen are its principal constituents. No phenomenon yet known indicates the presence of azote as a consti- tuent. But its being decomposable by nitric acid, ratlier favours the notion, that oxygen enters as an essential ingredient into its composition. SECTION XII. — OF CGDIIIRET. This substance has been lately discovered by Reichenbach. The only account of it which I have seen, is in Berzelius's Jahr-Berichtf for 1835, p. 408. Cedriret may be prepared by the following method : — The rectified empyreumatic oil, obtained by' distilling the tar of beech wood, was, by carbonate of potash, freed from acetic acid, and afterwards treated with a concentrated ley of caustic potash. The alkaline solution was freed from the insoluble portion of the oil, (eupion, capnomore, and mesite,) and the potash saturated with acetic acid. This occasioned the separation of a portion of the dissolved oil, while another portion remained in combination with the acetate of potash, from which it was separated by distillation. When about a third part of it had come over, the receiver was changed, and it was tried whether a drop of the oil, distilling over, when let fall into persulphate of iron, occasioned a red precipitate. As soon as this precipitate began to be formed, the oil that distilled over was collected. It had the property of striking a red colour with persulphate of iron or chromotartrate of potash, and after an interval of about five minutes, a precipitate of red crystalline needles fell. This preci- pitate fell slowly, and left the liquid colourless. All substances which easily part with oxygen, produced a similar phenomenon. Even the oxygen of the atmosphere rendered the liquid red. These red crystals were called Cedriret by Reichenbach, fTsn cedrium, an old name for the sour water of tar burners, and rete, c net, because crystals lie upon the filter, entangled in each other like a net. Cedriret possesses the following properties : — It crystallizes in fine red needles, which take fire, burn with flame, and disappear without leaving any residuum. It does not melt, but when heated is easily decomposed, and if the temperature be raised still higher, it is charred. Sulphuric acid, free from nitric acid, dissolves it with an indigo-blue colour, which, when heat is applied, or when the acid is diluted, becomes yellowish-brown, Dilute nitric acid has no action on cedriret ; but concentrated add decomposes it entirely. Acetic acid, of the specific gravity 1*07, dissolves a little of it, which is not separated when the acid is saturated with ammonia. It is insoluble in bisulphuret of carbon, water, alcohol, ethers, oil of turpentine, eupion, picamare, capnomore, petroleum, oil of almonds, and fused paraffin. But it dissolves, cold, in creosote, with a pur- ple colour, and from this solution it may be precipitated in crystals 3b f I 738 PRODUCTa OP DISTILLATION. by alcohol. The solution is decomposed both by the solar rays and by heat. The cedriret is destroyed, and assumes a yellow colour. Reichenbach is of opinion, that cedriret, and its solution in liquids containin<7 creosote, and its easy decompositions, will enable us to account for the numerous changes of colour which are observed iti pyrolignic acid and tar. SECTION XIII. — OF NAPHTIIAMN. An account of the mode of obtaining naphthalin and its princi- pal characters, has been given in the Chemistry of Unorganized Bodies (vol. i. p. 205). My object here, will be to state the addi- tional facts respecting this interesting substance, which have been determined since the year 1831, when that account was drawn up. Reichenbach has endeavoured to prove that naphthalin does not exist ready formed in coal tar ; but that it is formed when the oil existing in this tar is exposed to a high temperature.* But M. Laurent distilled a quantity of tar previously deprived of its water, by exposing it to heat in an open vessel. The oil which came over first, and before the heat was very much elevated, being exposed to a cold of zero, by plunging it into a freezing mixture of snow and salt, abundance of crystals of naphthalin were deposited. This process does not always succeed ; but if a current of chlorine gas be passed through this oil, it darkens in colour, giving out muriatic acid, and at last becomes black. If this oil be agitated with water acidulated with muriatic acid, and then enough of ammonia added to neutralize the acid, a white flocky matter falls, which gradually concretes into greenish globules. The odour of this substance is 80 penetrating, that if we simply touch it with the point of a finger, we retain a perceptible smell of it for four or five days. Laurent dis- tilled over this altered oil, and divided the product into two portions. The first was limpid, very fluid, exhaled acid vapours, and was not altered by exposure to the air. The second was yellow, oily, and similar to that obtained in the distillation of tar. Both of these liquids when cooled down to zero (indeed, even as high as 41°), deposited abundance of crystals of naphthalin. The quantity, in- deed, is so great, that M. Laurent informs us that, by this process, naphthalin could be obtained at a low price, if it were to be applied to any useful purpose.t Naphthalij crystallizes in rhomboidal plates with angles of 122° and 78°.$ Chlorine and bromine act with considerable violence on naph- thalin ; heat is disengaged, and muriatic acid and hydrobromic acids formed. It is not altered by iodine. When the two bodies are melted together, they separate during the cooling. The same remark applies to phosphorus, sulphur, chloride of sulphur, and bisulphuret of carbon. Potassium may be melted in naphthalin without alteration. * Ann. de Chim. et ilo Phys. xlix. ."JG. X Laurent, ibid. p. 218. tibid. xlix. 214. NAPHTHAI.IN. 739 rays ond ;V colour, in iHiu'ids able U9 to aserved in , its princi- fnorganized e the addi- bave been drawn up. In does not wben the oil .* But M. of its water, •b came over g exposed to of snow and sited. This chlorine gas out muriatic ;d with water nmonia added lich gradually , substance is ,nt of a finger, , Laurent dis- ) two portions. 3urs, and was 3 yellow, oily, Both of these high as 41°), e quantity, in- )y this process, B to be applied angles of 122° ence on naph- d bydrobromic the two bodies :,g. The same ,f sulphur, and in napbthalm Dumas found the melting point of naphthalln 174°, which accords with my previous cxperhnont. Its boiling point, ho says, is 413°^. Dr Kid had previously found it 410°. The specific gravity of its vapour, according to buiniis, is 4*528. Naplithalin was subjected to nnalysis by Faraday, Oppermann, and Laurent, '•■" - i' " • . ii ■ 'i i. . . The following table shows the resultd obtained : — Faraday.* Oppermann f Laurent t Mean. Carbon Hydrogen 100-00 I 99'44 lOO-O , 100 Now, the number of atoms which correspond best with these propor- tions, and with the specific gravity of the vapour of naphhalin, is 10 atoms carbon = 7*5 or per cent. 93*75 4 atoms hydrogen =0*5 — — 6*25 8 100 The specific gravity of carbon vapour being 0*4 166, and that of hydrogen 0*0694, it follows that 10 atoms of carbon weigh 4 atoms of hydrogen 4*IG66 0*2777 4*4444 MM. Wohler and Liebig have shown that 13*92 parts of sul- phuric acid are saturated by 45*58 parts of naphthalin. According to this experiment, 16*372 parts of naphthalin combine with 5 acid. Hence it is probable that 2 atoms naphthalin combine with 1 atom of sulphuric acid. When a current of chlorine gas is passed over naphthalin at the or- dinary temperature of the atmosphere, the naphthalin melts, and if the disengagement of chlorine be rapid a portion is volatilized, which con- denses in the form of a new product on the surrounding bodies. At the same time vapours of muriatic acid are exhaled. When the greatest part of the naphtb(»li>» has been acted on, the liquid thickens gradually, a white granular matter is deposited ; at last, the whole assumes a solid form, similar in appearance to frozen olive oil. If the whole naphthalin has not been acted on, we must apply a gentle heat to liquefy this solid product, and continue the current of chlo- rine till saturation takes place. Wlien the action is at an end we find two new compounds ; the one solid, white, and granular ; the other oily, having a light-yellow colour, and retaining in solution a cer- tain quantity of the preceding solid. M. Laurent, to whom we are indebted for the investigation of these two chlorides of naphthalin, § purified the solid chloride in the • Phil. Trans. 1826 "j- Ann. de Chim. et de Phys. xlix. 43 161. i.i \ Ibid. p. 221. § Ann. de Chim. et de Phys. lii 875. 740 rnoDUCTS of dihtiixation. followinir manner : — Mo introduced it into a glass tube sliiit at one end, and poured over it about five or six times its volume of ether, and agitated the whole rapidly. The ether dissolves with facility the oily chloride, while it scarcely acts on the solid chloride, which was deposited speedily when the tube was left at rest. This other was poured off, and a new portion introduced, and agitated as before. This process was repeated three or four tinica, and finally tho whole was thrown on a filter, the solid chloride was washed with a little ethor, and finally exposed to pressure between folds of filtering paper. If we now dry or melt this chloride to get rid of any adhering ether, it is perfectly pure. It is much more difficult to obtain the oily chloride free from tho solid chloride of naphthulin. M. Laurent adopted the following method : — The ethereal liquids employed in washing tho solid chloride were distilled in a retort, taking care to proceed no farther than to draw off tho greatest part of tho ether. The residue was exposed to a cold of zero, by means of a freezing mixture of snow and salt. A long exposure to tbia degree of cold is necessary, in order to cause the deposition of the solid chloride. Sometimes none of it is do- posited after an hour at zero, though it crystallizes when left two days in a temperature of 41°. After the deposition of the solid portion, the oily chloride was drawn off by a sucker, and the ether driven off from it by means of heat. 1. Solid chloride of naptdhalin. This chloride is obtained some- times in the state of a white crystalline powder, and sometimes in transparent rhomboidal plates, having a glassy lustre. To procure it under this last form, we must dissolve it in boiling ether. When the liquid cools, the chlorine is deposited in crystals. The best way of obtaining the ethereal solution, is to put the chloride, with the ether, into a strong globular glass vessel, furnished with a ground stopper, which is to be tied down. The vessel is placed on the sand-bath, and heated some degrees above the boiling point of ether. When the chloride has dissolved, the whole is allowed to cool slowly on the sand-bath. By this means fine crystals are obtained. They are rhomboidal plates, with angles of about 75° and 105°. These crystals are very brittle, and easily reduced to powder. This chloride melts, when heated, to 320". On cooling it con- cretes into a crystalline mass. At a higher temperature it boils, and undergoes decomposition. Va])ours of muriatic acid are disen- gaged, and a new product is obtained, which is fusible and incrystallizable, while at the bottom of the retort there remains a quantity of frothy charcoal. When heated in a glass tube, open at both ends, it is volatilized without decomposition. It is insoluble in water. Boiling alcohol dissolves a very minute quantity of it, which is deposited again almost entirely when the liquid cools. It is more soluble in etbcr, especially when assisted by heat. It has a strong and peculiar smell. It is not altered by NAlMITilAl.lN. 741 it tit OTIO of ether, \\ fttcUity lo, which 'his ether as \)eforc. inaWy the led with a )f filtering adhering c from the ) following iloridc were mn to draw jtposed to a nd salt. A der to cause J of it is de- dien left two , of the solid nd the ether itained some- soinetimes in To procure ■thcr. Wlien The hest way •idc, with the (vith a ground placed on the )oint of ether. to cool slowly )tained. They 105°. These sr. cooling it con- rature it boils, acid are disen- is fusible and here remains a 13 tube, open at s a very minute itirely when the ly when assisted t not altered by 1 oxnoaure to the air. When melted upon paper and then kindled, it burns with u thick Hanio, ^reen on tlie ed^MVi, and is'wea out a great deal of smoke ; by itself it will not burn, not even when in the state of vapour. Chlorine, bromine, and iodine, have no action on it. Potassium, at the ordinary temperature, or when slightly heated, decomposes it with a slight explosion and the production of light. (Chloride of potassium is formed, and a great deal of charcoal deposited. If the experiment be nmde in a glass tube, a gas is disengaged, which burns with u green tiame. Sulphuric acid while cold, docs not alter it ; but when long boiled on it decomposition takes place. Nitric acid does not act upon it, unless when kept at a boiling temperature. It then very slowly elmngcs it into small yellow crystals. Muriatic acid and ammonia have no action on it. Potash, while cold, does not seem to alter it. l^ut when boiled upon it a new crystalli/able compound is formed, and the potash is changed into chloride of potassium. It was very carefully analyzed by M, Laurent and by Dumas, who obtained I Ijiuietit. I Uutntt. i Carbon Hydrogen Chlorine The numbers of Dumas lead composed of 10 atoms carbon 4 atoms hv'lrogen 2 atoms chlorine loo-oo* I loot i :o the conclusion that the chloride is 7-5 0*5 9-0 17 Hence, it would appear to be a compound of 2 atoms chlorine and 1 atom of napbtbalin. But the evolution of muriatic acid during its formation, renders this oj)inion unlikely. Laurent, who was at great pains in determining the (juantity of hydrogen, obtained a re- sult, which corresponds with 10 atoms carbon = 7'5 or per cent. 44*33 3 i atoms hydrogen = 0*41 () — — 'i'4() 2 atoms chlorine = 9 — _ 53-21 16'91(i 100-00 The probability is, that the true composition is 10 atoms carbon =7*5 or per cent. 44-44 3 atoms hydrogen = 0-375 — _ 2-22 2 atoms chlorine = 9-0 — — 53-34 16-875 ♦ Ann. de Chiin. ct ilc Phys. lii. 280. 100-00 t Ibid. I. 185. II i I I 742 PRODUCTS OF DISTILLATION. For these numbers do not deviate farther from the results of Lau- rent, than the amount of the unavoidable errors to which such delicate experiments are liable. But, if these atomic constituents be admitted, it is not naphthalin in combination with chlorine, but a new compound, composed of 10 atoms carbon, and 3 atoms hydrogen. This new compound approaches pretty closely to the constitution of idrialin, as will appear in a subsequent Section. 2. Oiht chloride of naphthalin. This chloride, as it was obtained by M. Laurent, is an oily liquid, having a light-yellow colour, heavier than water, and distinguished by a smell similar to that of the solid chloride. It is insoluble in water, but very soluble in alcohol. Ether combines with it in all proportions. It seems to be capable of being distilled over without decomposi- tion. It does not burn by itself when heated in an open spoon ; but it burns with a green flame when spread upon paper or wood, giving out at the same time a good deal of smoke. Nitric acid converts it into a yellow viscid matter. Potassium, even when assisted by a boiling temperature, does not appear to alter it. Potash is equally without action. Laurent subjected to an ultimate analysis a quantity of this liquid chloride, containing in solution a certain quantity of solid chloride, from which he was unable to free it. The result was Carbon 54-9 or 90 atoms = 67'5 Hydrogen 3-3 or 32-5 atoms = 4-0625 Chlorine 41'8 or 11'5 atoms = 51*75 100-0* 123-3125 But M. Laurent considers the true constituents to be 90 atoms carbon = 67*5 or per cent. 55-66 34 atoms hydrogen =4-25 — — 3-51 11 atoms chlorine =49*5 — — 40-83 121-25 100-00 If these numbers be not considered as deviating too far from the results of the analysis, it is obvious that we may resolve them into 7 (C" H^ + Ch) + 2 (C'° H^ + Ch^) But C" H' + Ch'' represents an atom of the solid chloride of naphthalin. C'° H* + Ch must represent the constitution of an integrant particle of the oily chloride. And the substance analyzed was obviously a mixture of 7 atoms oily chloride of naphthalin 2 atoms solid chloride of naphthalin. If this ingenious reasoning be admitted, then it follows that the oily chloride is a compound of 1 atom of naphthalin, and 1 atom chlo- rine. If the oily chloride be a compound of * Ann. de Chim. et de Phys. Hi. 283. NAPHTHALIN. 743 10 atoms carbon 4 atoms hydrogen 1 atom chlorine = 7-5 = 0-5 = 4-5 12-5 then its atomic weight will be 12*5, and it will be composed, per cent., of Carbon . . . . . 60 Hydrogen 4 Chlorine ..... 36 100 3. Nitronaphthalase. This compound was discovered in 1835, by M. Laurent.* When nitric acid and naphthalin are left in contact at the com- mon temperature of the atmosphere, no action takes place. But if we boil the acid, red vapours are emitted, and an oily layer collects on the surface, which, in i>'^out 20 minutes, quite changes its nature. We obtain a yellow oil, wl.'ijh becomes solid very slowly after cool- ing, forming a crystalline mass in yellow needles. This matter is composed of two products, very soluble in alcohol and ether : one, oolid, which is nitronaphthalase; the other, a liquid which is partly separated by pressure between the folds of blotting paper. To separate the whole of the oil, the impure nitronaphthalase is dis- solved in boiling alcohol in a capsule. On cooling, it deposits first, drops of oil. These are separated by a sucker. They contain a great deal of nitronaphthalase. The alcohol being left at rest for 12 hours deposits fine crystals of nitronaphthalase. It is purified still farther, by one or two additional crystallizations. Nitronaphthalase may be prepared in another way, by means of hyponitrous acid. To the beak of the retort containing the nitrate of lead, we adapt a large tube, bent like U. In the bend of this tube we put naphthalin, and then apply heat to the retort. The hyponitrous acid disengaged acts cold with great energy on the naphthalin. We obtain here also nitronaphthalase, together with an oil. It is to be purified, as before directed. Nitronaphthalase crystallizes in long square prisms, terminated by very acute pyramids. Its colour is sulphur-yellow. It melts at 109°^ ; and when it becomes solid, the thermometer suddenly rises to 129°. It may be sublimed without decomposition. The vapour is deposited on cold bodies in small needles. When we operate on a large quantity, or raise the heat suddenly, it is decomposed at once with the disengagement of a red light, and leaving behind it a great quantity of charcoal. When heated on platinum foil it burns with a red flame and much smoke. It is neutral, insoluble in water, but very soluble in alcohol and ether. Chlorine decomposes it with the assistance of heat. We ob- '11 * Ann. (Ic Chim. et de Phvs. lix. .'}76. 744 PRODUCTS OF DISTILLATION. tain an orange-red oil, which concretes on cooling. It possesses the characters and composition of chloronaphthalase. Bromine, in like manner, produces bromonaphthalase. Iodine has no action on it. When heated with sulphur it melts, then dissolves the sulphur ; and if the solution be heated it boils, sulphurous acid is disengaged, and a green matter, not homogeneous, is obtained. One portion of it is soluble in ether, to which it gives a green colour. Potassium suddenly decomposes nitronaphthaluse at the temperature of 109°^. Light is disengaged, and charcoal evolved. Muriatic acid has no action on it. Nitric acid converts it into nitronaphthalase. Concentrated sulphuric acid dissolves it without alteration, and water throws it down. At a boiling heat the acid becomes brown, and then water occasions no precipitate. Caustic potash ley produces little change upon it, even at a boiling tempera- ture. But in an alcoholic solution of potash it becomes red, and concentrated sulphuric acid changes it to green or bluish-green. M. Laurent subjected it to an ultimate analysis, and obtained Carbon 69*86 or 20 atoms =15 or per cent. 69*36 Hydrogen 4*06 or 7 atoms = 0*875 — — 4*04 Azote 8*5 or 1 atom = 1'75 — — 8*19 Oxygen 17*56 or 4 atoms = 4*00 18*50 100 21*625 100*00* It is easy to see now what happens when nitric acid acts on naph- thalin. 2 atoms of naphthalin are C^° H^ 1 atom nitric acid . Az O* 1 atom nitronaphthalase C'^« H8 Az O* C2« W Az O* Difference . . HO So that 1 atom of the nitric acid loses an atom of oxygen, while the naphthalin loses an atom of hydrogen, both together being con- verted into water. 4. Nitronaphthakse. This substance was also described by M. Laurent, in 1835.t When nitronaphthalase is boiled for a long time in nitric acid, we obtain a new crystalline substance, which Laurent has called nitronaphthalese. But this process is tedious. It is better to boil the acid with nitronaphthalase, while under the form of a layer of • M. Laurent does not furnish us with the data on which his numbers are founded, but only the result of his analysis per cent. This prevented me from correcting his numbers ; and hence the want of coincidence between the analysis and' the formula, which would have nearly disappeared, had the requisite correc- tions been applied. t Ann. dc Chira. et de Phys. lix. 381. NAPHTHALIN. 745 possesses omine, in QO action sulphur ; ^engaged, portion of Potassium of 109H- rts it into it without ,t the acid Caustic or tempera- s red, and -green, (btained . 69-36 . 4-04 8-19 18-50 100-00* is on naph- fii, while the being con- ibed by M. nitric acid, has called etter to boil if a layer of 9 numbers are ented me from m the analysis jquisite correc- oil. We porate rftpidly in a flask. If we watch till the oil and acid becor -,:, nearly of the same bulk, and then stop the process, the whole concrttes into a solid mass on cooling. Wash it with hot water, and then with hot alcohol, in which it is nearly insoluble. It is nitronaphthalese under the form of a light powder composed of minute needles. It is insoluble in water, very soluble in boiling alcohol, and slightly so in ether. It melts at 365°. When strongly heated it sublimes in small needles without decomposition. But when a con- siderable quantity is heated at once, it is suddenly decomposed with a violent disengagement of gas, while much charcoal is deposited. A good deal of light is evolved. Nitric and muriatic acid have no action on it. Concentrated sulphuric acid dissolves it with the assistance of heat. On cooling the nitronaphthalese is deposited in needles. It is also precipitated by water. When melted with sulphur, sulphurous acid is disen- gaged, and sulphuretted hydrogen. Concentrated boiling potash ley alters it but little ; the solution becomes brown and some ammo- nia is disengaged. Laurent subjected it to analysis, and states its composition to be Carbon 54-6 or 20 atoms =15 or per cent. 55*05 Hydrogen 2*9 or 6 atoms = 0-75 — — 2-75 Azote 12-7 or 2 atoms =3-5 _ _ 12-85 Oxygen 29-8 or 8 atoms =8-0 — — 29-35 100-0 27-25 100 We see from this that the nitric acid takes away another atom of hydrogen, and adds an additional atom of nitrous acid, or Az O* to the nitronaphthalase. 5. Naphthalose. This substance was also discovered and de- scribed by M. Laurent, in 1835.* If we mix nitronaphthalase with 8 or 1 times its weight of lime slightly moistened in a small retort, so that it shall be full to the neck, and apply heat, a brown oil is disengaged, containing much naphthalin, together with ammonia, and nitronaphthalase undecom- posed, and there is condensed in the neck of the retort a thick oil, which becomes solid on cooling. The lime is blackened by the de- position of charcoal. We must heat very gently, otherwise the whole takes fire, and very little of the products just mentioned are obtained. To obtain the solid matter in the neck of the retort, we cut it off as near the throat as possible, and wash the solid matter with ether, which dissolves the foreign matter. A yellow powder remains which is naphthalase. It is insoluble in water and alcohol, and scarcely soluble in ether. It does not melt at 482°, but at that temperature it begins to sublime. If the heat be increased, it melts and then boils. Its vapour is yellow, and it condenses in scales or long yellow needles. • Ann. de Chim. et de Phvs. lix. 383. [' I I II 746 I'RODUCTS OF DISTILLATION. When the smallest quantity of it is dissolved in cold sulphuric acid, the whole liquid assumes a very strong and fine violet-blue colour. Water throws down the naphthalase unaltered, and it becomes again blue by the contact of concentrated sulphuric acid. Idrialin also strikes a blue with sulphuric acid, but only when heated, and nitric acid destroys this power in idrialin, but not in naphthalase. It was analyzed by M. Laurent, who obtained Carbon 87*0 or 20 atoms =15 or per cent. 88*89 Hydrogen 4*8 or 7 atoms =z 0*875 — — 5*18 Oxygen 8*2 or 1 atom =1 — — 5*93 100*0 16*875 100 But this formula deviates too far from the analysis to be adopted. The analysis leads to the formula 14 atoms carbon =10*5 or per cent. 87*04 4^ atoms hydrogen = 0*5625 — — 4*67 1 atom oxygen -=1 — — 8*29 12*0625 100*00 But as the analysis was only once made, no great reliance can be placed on it. Laurent considers it as hitronaphthaiase, minus an atom of hy- ponitrous acid. But we have no evidence that it does not contain azote. SECTION XIV. OF PARANAPHTHALIN. This substance was discovered by M. Dumas in 1832, in coal tar, and named by him paranaphthalin, because from his experi- ments it appears in its composition to be perfectly identical with naphthalin.* When we distil coal tar, the products obtained may be divided into four different sets. The first product is an oily substance, which furnishes a good deal of pure naphthalin. The second pro- duct is also oily ; but it yields both naphthalin and paranaphtha- lin, which may be separated from each other by means of alcohol. The third product is viscid ; it contains, so to speak, only para- naphtalin ; but it is accompanied by a viscid substance, which renders its purification very difiicult. The fourth product is dis- tinguished from the third, by containing the reddish-yellow or orange substance, which appears at the end of all similar distillations. To obtain paranaphthalin from the second of these products, we have only to expose it to the temperature of zero, by means of a freezing mixture of snow and salt. The paranaphthalin is de- posited in crystalline grains. Let it be thrown upon a cloth and pressed, in order to separate the liquid portion. If we now digest it in alcohol, the naphthalin and other substances which it contains are dissolved, and the paranaphthalin remains in a state of con- * Ann. de Chi.... eJ de Pins I. 187. PAHANAPHTHALIN. 747 pic acid, > colour, les again alin also nd nitric It was 3-89 5-18 5-93 ! adopted. ) ice can be torn of by- lot contain 32, in coal bis experi^ entical with r be divided substance, second pro- aranapbtba- 5 of alcohol. ;, only para- ance, which )duct is dis- ib-yellow or distillations, se products, y means of a ibalin is de- . a cloth and e now digest •h it contains itate of con- siderable purity. If we distil it over two or three times successively, it will be rendered quite pure. The third and fourth products of the distillation of coal tar, must be treated somewhat differently. Let the whole of them be dis- solved in the smallest possible quantity of oil of turpentine, and let the solution be cooled down to zero. The paranaphthalin crystal- lizes in hard grains. The whole is thrown on a cloth through which the liquid is pressed. After being washed in alcohol, it is purified as before by repeated distillations. Paranaphthalin thus purified melts at 356°, while naphthalin melts at 174°. Its boiling temperature exceeds 572°. Yet it may be distilled over unaltered ; or at least the quantity of charcoal which it leaves, diminishes at each distillation, and becomes at last almost insensible. It is easily sublimed before fusion. It con- denses in plates, the figure of which has not been determined. It is insoluble in water, and scarcely soluble in alcohol, even at a boiling temperature. What dissolves, again precipitates in flocks when the solution cools. This distinguishes it from naphthalin, which dissolves abundantly in hot alcohol, and precipitates in crystals when the solution cools. Ether acts like alcohol. The best solvent is oil of turpentine. Concentrated sulphuric acid dissolves paranaphthalin by the assistance of heat. The solution has a dirty-green colour, owing probably to the presence of a little of the orange-coloured matter which always accompanies it. Nitric acid attacks it, nitrous vapours are exhaled, and a stance remains, which sublimes, at least partially, in needles. Dumas subjected paranaphthalin to an ultimate analysis, mean of three analyses gave Carbon . 923 or per cent. 93*85 Hydrogen . 6-05 — — 6-15 sub- The 98-35* 100-00 This is obviously the same with the composition of naphthalin or 10 carbon . . . . 7'5 4 hydrogen 0-5 8-0 Dumas determined the density of the vapour of paranaphthalin, by heating it to the temperature of 842°, determined by an air thermometer. The specific gravity was 6-741, supposing the tem- perature reduced to 32°. Now 15 volumes carbon weigh . 0-25 6 volumes hydrogen . . 0-4166 6-6666 It is clear from this, that a volume of vapour of paranaphthalin is • Ann. de China, et de Pbvs. I. 190. ?i 748 PRODUCTS OF DISTILLATION. composed of 15 volumes of carbon vapour, and G volumes of hy- drogen gas. The number of atoms in a volume of paranaphthalin vapour is to that of naphthalin vapour as 3 to 2. So that, though the ratio of the elementary constituents is the same, yet the number of atoms requisite to constitute an integrant particle is different in each. Thus it appears, that various multiples of 10 carbon + 4 hydrogen, may enter into combination as well as of 1 carbon + 1 hydrogen. M. Laurent, by treating paranaphthalin with nitric acid and subliming, obtained a substance crystallized in needles, to which he has given the name of paranaphthalese* This substance is white, insipid, destitute of smell, and may be volatilized in small quantities without decomposition. When heated on platinum foil it burns with a fuliginous flame and leaves a residue. It is neutral and insoluble in water and alcohol, and scarcely soluble in ether. It is not altered when heated with muriatic acid, potash or lime. Boiling naphtha dissolves a little of it. Hot concentrated sulphuric acid is its best solvent. Nitric acid dissolves a little of it. M. Laurent found its constituents Carbon 80*8 or 15 atoms z= 10*5 or per cent. 79*24 Hydrogen 3*6 or 6 atoms = 0*75 — — 5*67 Oxygen 15*6 or 2 atoms =2 — — 15*09 13*25 100 Making it to differ from paranaphthalin, by the addition of 2 atoms of oxygen. But if this formula be correct, the substance analyzed must have been very impure. SECTION XV. — OF IDRIALIN. This remarkable substance, which occurs in the mercurial mine of Idria, in that variety of ore called on the spot branderZf was first made known to chemists in 1814, by M. Paysse, in his statistical notice of the Mercurial mine of Idria.t When branderz is distilled, idrialin comes over in brilliant plates, light and micaceous, melting like wax when exposed to a gentle heat, and burning with the ex- halation of a balsamic odour. No notice was taken of this account of idrialin, by M. Paysse, either by mineralogists or chemists. No specimen of branderz is to be found in any mineral collection that I have seen ; nor am I aware of any allusion to it either in mineralogical or chemical works, till it drew the attention of M. Dumas in 1832. He could find no specimen of branderz in the rich mineral cabinet belonging to the Ecole des Mines at Paris. In the mineral collection of the Jardin du Roi, there was only a small fragment ; but luckily some pieces of it existed in the collection of the Ecole Polytechnique which enabled him to make some experiments.^ The pieces of branderz which he procured, resembled common • Ann. de Chim. et de Pliys. Ix. 220. f Ann. dc Chim. xci. 201. X Ann. de Chim. ct de Phys. I. 193. IDRIALIN. 740 i of hy- phthalin , though number ferent in •bon + 4 rbon + 1 acid and which he is white, quantities lurns with insoluble It is not Boiling ric acid is ;. Laurent 79-24 5-67 15-09 00 of 2 atoms B analyzed urial mine , was first statistical is distilled, us, melting rith the ex- M. Paysse, branderz is , nor am I nical works, ould find no iging to the ■ the Jardin some pieces nique which led common xci.201. coal very much, excepting that^they had a brown colour.''^ One of them contained no mercury, and the two others only traces of that metal. When heated gently in a glass tube open at both ends they melted, and allowed a great quantity of crystalline powder to exhale. This substance is what Dumas has distinguished by the name of idrialin. To obtain idrialin, considerable precautions are requisit:^. For, unlike napththalin and paranaphthalin, it is not volatile without decomposition. Dumas procured it in the following manner : — The mineral broken into fragments was put into a tubulated retort, whose neck, almost vertical, plunged into a long and narrow glass cylinder. A current of carbonic acid gas was made to pass through the retort. Heat being cautiously applied, the? mineral melted and boiled, giving out first mercurial vapours, and then idrialin in abun- dance. The process was continued till the retort melted, and the evolution of idrialin went on to the end without the least trace of water, bitumen, or oil. To free the idrialin from the mercury which was disseminated through it, the whole was digested in oil of turpentine at a boiling temperature. When the solution cools, the idrialin is deposited so rapidly that the whole mixture becomes almost immediately solid. It is separated from the oil of turpentine by filtration and pressure between folds of blotting paper. Idrialin is volatile, but it does not rise without being altered in its nature. When we attempt to distil it, we lose at least ygths of the whole, even when we operate in vacuo, or in a current of car- bonic acid gas. Idrialin may be fused, but at a temperature so high that we can scarcely fuse it without altering its nature. It is not sensibly soluble in water even at the boiling temperature. It is scarcely soluble in boiling alcohol or ether. The only known solvent of it is oil of turpentine. The oil must be boiling hot, and the idrialin precipitates whenever the solution cools. When sulphuric acid is heated in contact with idrialin, that sub- stance is dissolved and the solution assumes a fine blue colour like that of sulphate of indigo. M. Dumas subjected idrialin to an ultimate analysis, and ascer- tained that its only constituents were carbon and hydrogen. He found the constituents Carbon 94-8 or 3 atoms = 2*25 or per cent. 94*73 Hydrogen 5-2 or 1 atom =0*125 — — 5-27 100*0 2*375 100*00 As we neither know the atomic weight of idrialin, nor the specific gravity of its vapour, we can draw no conclusion from this analysis respecting the number of atoms which enters into its composition. But it is obvious that this number must be a multiple by a whole number of 3 atoms cavLon + 1 atom hydrogen. M. Dumas has rendered it exceedingly probable that idrialin exists ready formed in branderz. When oil of turpentine is boiled with :- 750 PRODUCTS OF DISTILLATION. the powdered mineral, it deposits, on cooling, some crystals of idrialin. Even alcohol at a boiling temperature dissolves from the mineral a little idrialin. For if we filter and evaporate this alcohol it deposits some plates having a pearly lustre. If these plates be washed in cold water and then digested in hot sulphuric acid, the liquid immediately assumes the fine blue colour which characterizes idrialin. It is said that hranderz is no longer to be found in the mine of Idria. If this be so, it will not be in the power of chemists to sub- ject idrialin to further experiments. SECTION XVI. — OF EBLANIN.* This name has been given by Mr Scanlan, to a substance dis- covered by him in raw pyroxylic spirit. Unless I am mistaken, he gave an account of the mode of obtaining it, and described its most remarkable properties at the meeting of the British Scientific Asso- ciation at Bristol, in 1 836. And an account of it together with an analysis by Drs Gregory and Apjohn, was published in Liebig's Annalen der Pharmacie, for 1837.t To obtain it, raw pyroxylic spirit is distilled over slacked lime. The dry residue is a mixture of lime, acetate of lime, and ehlanin. The lime is taken up by dilute muriatic acid, and the residue is digested in spirit of wine. From this solution the eblanin is de- posited in long needles or prisms, having the colour of carbazotate of potash. It has no smell. It is insoluble in water and in the alkalies, but soluble in alcohol, ether, and concentrated acetic acid ; and is thrown f this kind of soot. Whoever has entered a Highland cottage, in whicli the smoke can make its escape only by the doors and windows, and which must there- fore have the upper part of the room always full of smoke, must have observed, that all the rafters are black as jet, and shining as if covered with japan. Hence it is obvious, that a portion of the soot must have been deposited in a liquid state at first, and gradually assinned the consistence of pitch or resin, by exposure to the air. When we examine a chimney, at the bottom of which nothing is burnt but wood or peat, we find the soot at the lower end in brilliant masses, precisely similar to that which has attached itself to the rafters ; but farther up in the chimney it has a pulverulent form. It was this last species of soot that Braconnot subjected to examina- tion. Soot, as is well known, has a black colour, an exceedingly dis- agreeable and bitter taste, and a peculiar and rather unpleasant smell. It burns like tinder, giving out during its combustion, a very dis- agreeable odour. When boiled with water, it softens, and acquires a kind of duc- tility. The water assumes a dark brown colour, and lets fall on cooling, or at least when concentrated, a matter which has the appearance of pitch. This pitchy matter, when frequently boiled with new portions of water, is partly dissolved, and leaves a sub- stance which no longer melts when heated, but which possesses all the characters of ulmin. The portion dissolved in water, when obtained by evaporation and digested in alcohol, left a red substance having little taste, and destitute of bitterness. This substance is very soluble in water, and is doubtless of a peculiar nature. Braconnot calls it animalizea matter^ for what reason does not appear. The portion dissolved in alcohol being obtained by evaporation, and digested in ether, gave out a yellow oily-looking matter to the ether, which had an exceedingly acrid and bitter taste. This sub- stance Braconnot distinguishes by the name of asbolin (from ao£oX>j, soot). It is fluid and not volatile. When mixed with a small quantity of cold water, it swims on that liquid like an oil ; but if we increase the quantity of the waetr, we obtain a yellowish bitter solution. This solution is precipitated in yellow flocks by acetate of lead. With nitrate of silver it becomes slightly cloudy at first, but after standing some time, it assumes a brown colour, and a pellicle of metallic silver appears on the surface. Sulphated peroxide of iron, strikes with it a deep brown, almost black colour. Barytes water, lime water, ammonia, and the alkalies in general, strike with it an intense red colour. The infusion of nutgalls occasions a precipitate. Alcohol dissolves it readily, and the solution does not become * Ann. lie Chini. ct ile Pliys. xxxi. 37. 3 c i 754 l>nODUCT8 Of DISTILLATION. ■|i muddy when mixed with water. When heated, it hums with a ittrong flame like the fixed oild. Hut it is in^^oluble both in fixed oils, and in oil of turpentine. Nitric acid diHsolves it readily, givin{]^ it a reddish-yullow colour. The solution, evaporated to dryness, yields much yellow hitter prin- ciple, and very little oxalic acid. The constituents of wood soot, according to the analysis of Ura- connot, are the following : — Ulmin 30-20 Animali/ed matter 20*00 Asbolin , 0*50 Water '. 12-50 Carbonate of lime, with some carbonate of magnesia 14'6(i Acetate of linio ...... r)'(»/5 Sulphate of lime oOO Acetate of potash 4*10 Charcoal . 3*85 Ferro phosphate of lime .... 1*50 Silica 0*95 Acetate of magnesia ..... 0*53 Chloride of potassium ..... ()"36 Acetate of ammonia 0*20 Acetate of iron ...... trace 100-00 No doubt otlier substances besides those discovered by Braconnot exist in soot. PVom its powerful anticeptic properties, we may bo sure that creosote exists in it. It very probably contains also capno- jnorc. Indeed we may look for most of the bodies recently dis- covered by Reichcnbach. SECTION XVIII. — OF ANIMAL CHARCOAL. Though this substance, which of late years has become so im- portant to manufacturers, be derived from the animal kingdom ; yet as it undoubtedly owes its most important properties to the charcoal which it contaii's, it seems not iiiipr ^<'v t" ji" ; an account of it here. What is called animal charcoal, .>.• icn,-" h'-'rh, is j^'^'^ired I'roui the bones of horses, sheej), and o:..'ri. iii . u are exposed to heat in close vessels, so as to drive off all the volatile matter. The earth of bones remains mixed intimately with a quantity of charcoal, which gives the whole an intense black colour. They are afterwards reduced to powder, and are then fit for use. The value of ivory lilack ('.'-ponds much upon the way in which it is prepared. If it has been calcined at too high a temperature, it is not sufficiently porous ; if too little, the animal matter remaining forms a kind of varnish, which covers the charcoal and prevents it from acting. The state of division in which animal charcoal is obtained has a great efTect upon its value. Prussiate of potash, it is well known, is obtained by burning a mixture of potash and animal matters, such as blood, ANIMAL CIIAIICOAL. 750 iH with u lixcd oila, iw colour, iltor prin- liii of Br*" 100-00 y liraconnot }, we may ha 19 also capno- recently dis- 'come 80 im- migdom; yet ) the charcoal unt of it here. "1 vped from i.uded to heat r. The earth liarcoal, which re afterwards value of ivory red. If it has ciently porous; iid of varnish, ,y. The state 'a great effect All, is obtained such as blood, horns, hoofs, &c., iu iron put< When thin tnattcr is lixiviated, uii animal ciiarcnnl remain "luch im. WniriouH m a diflooioiirin^ principle, than tluit nuido trom hour- ever [». Thi» may hf partly owin^ to its state oi more niiiiu> division; but unUuubtoiily th«» prcBeuce of the potash contributes hUu to fbt> ctft'ct. It wiirt discovered by Lowil/ of fc>t Petersburg, in the year 17S5, that common charcual has tlu- property of" disoolouvmg vegetable extracts.* And the dirtcovcry was prosecuted sitill farther, in a iuirious ])aper published by hnu in l7!)Lt In IMII M. Figuier, apothecary at Montpdicr, showed that aniinul s, instead of being discoloured, acqiiire a deeper tinge when agirated with animal charcoal. This is owing to tlie presence of a bro vn matter in animal charcoal when not sutficieutly calcined, which is - diible in alkalies. This substance possesses the characters of ulmii . The action of animal charcoal on coloured liipiids is usu, ily more rapid when they are hot, than when they are cold. Hence it is usnal to raise the liquid to be discoloured to the boiling temperature. The animal charcoal is then thrown in, and the whole is a.'itated for a short time, and then thrown on a tiller. The liquid passes through colourless. We must not boil the liquid whilf in t »ntact with tl e animal charcoal too long. For sometimes a portion if the colouring matter, after having been separated, is apt to be again dissoUod. When this happens, the discolouring process is always incomplete, even when an unusual quantity of animal charcoal is used. It would appear, from the following experiment of M. Bassy, that animal charcoal, when it discolours liquids, acts chemically upon the colouring matter. He diluted with water a quantity of indigo, dissolved in concentrated sulphuric acid, agitating the liquid with a sutHcient quantity of aninud charcoal, till it was com- pletely discoloured. The animal charcoal, thus impregnated with • Creli's riiomisdie Annalen, 178G, i. 211, &c. t Ibid. 1791, i. 3P8 ami 494. A translation of this last paper will be found in CrcH's Journal, ii. Ui.j, !237. ;|; Dumas, Trailc dc Cliiinie appVuiuee aux Arts, i. 448. m 766 PRODUCTS OF DISTILLATION. y.f indigo, was washed with a great deal of water, but not a particle of the sulphate of indigo was dissolved. But when the charcoal was digested in a solution of pota.ui, soda or ammonia, the sul- phate of indigo was dissolved, and the liquid became blue. It would appear that animal charcoal acts the part of a weak base, and unites with the colouring matter as with an acid. Animal charcoal being prepared from bones, contains always the calcareous salts of bones, namely, phosphates and carbonates of lime. Its constituents, in fact, are usually Charcoal containing azote . . 10 Carburet, or silicet of iron . . 2 Phosphate and carbonate of lime . 88 Sulphurets of calcium and iron . trace w 1 1 100 Now, M. Bussy has shown, that if we represent the discolouring power of animal charcoal by 100, and if we employ the ten per cent, of charcoal contained in it alone, its discolouring power is only 30. Yjt he did not find that phosphate and carbonate of lime possessed any discolouring powers at all. This extraordinary fact cannot easily be explained, in the present state of our know- ledge. The state of division of the charcoal seems to have a great effect upon its discolouring powers. This is probably the reason why the mixture of potash and animal matters employed in the manufacture of prussiate of potash is so much more powerful as a discolouring substance than ivory black. M. Bussy has shown, that its discolour- ing powers are ten times greater than those of burnt bones. The charcoal derived from animal matters alone discolours but little. But when such charcoal is mixed with earthy salts, it discolours well, and best of all when the salts are present, while the charcoal is making. All this shows the effect of porosity on the goodness of the cliarcoul. Charcoal from animal matters alone is brilliant, and is obviously composed of compact plates. When earthy salts are pre- sent, the particles of charcoal are kept at a distance by the earthy matters, and this insulation of the particles is most complete when salts are present, in consequence of the constant motion of the pasty mass during the process of carbonization. MM. Bussy and Pay en have shown, that the goodness of animal charcoal as a discolouring principle depends upon these circum- stances, and that it may be judged of with accuracy by its appear- ance : the more brilliant it is, the worse does it act, and the less lustre it has, the better does it act. The following table, drawn up by M. Bussy, from his own ex- periments, will convey a better idea of the discolouring powers of animal charcoal in various states, than any description could do :— * * Jour. i\v Pliariii. viii. :i.j7. STAPHYSIN. 757 Charcoal employed. Weight always 1 dram. Solution of Indigo* dia- coloured in dran-.D. 1 . Charcoal of bones 2. Oil calcined with artificial phosphate of lime . 3. Charcoal of bones washed with muriatic acid . 4. No. 3, calcined with potash 5. Lamp black calcined 6. No. 5, calcined with potash 7. Charcoal of carbonate of soda decomposed by phos- phorus 8. Do. of acetate of potash 9. Flour calcined with potash 10. Albumen or gelatin calcin'^d with potash . 11. Blood calcined with phos- phate of lime 12. Do. calcined with chalk 13. Do. calcined with potash . 32 64 60 1450 128 550 380 180 340 1115 380 570 1600 Solution of molasses discoloured in drams 9 17 15 180 30 90 80 40 80 140 90 100 180 Ratio from the indigo, 1-00 2-00 1-87 45-00 4-00 15-20 12-00 5-60 10-60 35-00 12-00 18-00 50-00 Ratio from the molasses. 1-00 1-90 1-60 20-00 3-30 10-60 8-80 4-40 8-80 15-50 10-00 1 1-00 20-00 CHAPTER XII. nd the less OF NEUTRAL COMPOUNDS, OFTEN CONTAINING AZOTE. These substances are obtained from plants by processes similar to those employed for obtaining the vegetable alkalies ; and as their constitution is similar, it is rather difficult to form any conception of the reason why they do not participate in the power which these alkalies have to neutralize acids. Their number will doubtless in- crease very much when chemists have leisure to examine the whole vegetable kingdom with the same attention that has been paid to a few medicinal plants. SECTION I OF STAPHYSIN. This substance, at first confounded with delphina, was obtained in a separate state, by Couerbe, by the process described while treating of delphina, and was first made known and described by him in 1833, in his paper on some quaternary substances of organic origin,\ It is a solid substance, of a slightly-yellow colour. Its * The solution of indigo contained isWth of its weight of indigo. So that a dram contains the thousundtii part of a dram of indigo. f Ann. de Chim. ct do Pliys. Hi. 3G3. ■?:! 758 NEUTRAL COMPOUNDS. taste is exceedingly acrid. It melts when heated to the tempera- ture of 392°, and at a higher temperature it gives out ammonia, and leaves a very great residue of charcoal. Nitric acid, when assisted with heat, destroys its properties, and converts it into a bitter resin, acid, and having a good deal of the aspect of cholesteric acid. Chlorine, at the common temperature of the atmosphere, produces no sensible effect. At 300° it deepens the colour of staphysin, renders it very brittle, and deprives it of its bitter taste. The alkaloid thus altered is partly soluble in ether and alcohol ; but the solution is not acrid. It is very little soluble in water. The dilute acids dissolve it ; but, according to Couerbe, do not form with it true salts. Its constituents, according to the analysis of Couerbe, are Carbon 72-67 or 32 atoms = 24 or per cent. 73-28 Hydrogen 8-80 or 24 atoms = 3 _ _ 9-16 Azote 5-35 or 1 atom = 1-75 — — 5-34 Oxygen 13-18 or 4 atoms =4 — — 12-22 100-00 32-75 100-00 Analogy leads to the conclusion, that these atomic proportions re- present the constitution of staphysin. If so, its atomic weight must be 32-75. SECTION II. OF CAFFEIN. A substance, to which the name caffein was applied, was dis- covered, in 1802, by INIr Chenevix.* It was obtained in a purer state by Runge,t in 1820, and Pfaff'l described it about the same time, and distinguished it from cafleic acid. Robiquet again discovered it it 1821, § and its properties were still farther examined by Pelletier|| and Garot.^ It may be obtained by the following process : — A cold infusion of coffee is treated with acetate of lead, which throws down the colouring matter, and caffcic acid. A current of sulphuretted hydrogen gas is passed through the liquid to throw down the excess of lead added. The filtered liquid being now con- centrated, the caffein is deposited in crystals. These crystals are white, have a silky lustre, and they may be rendered purer by crystallizing them a second time. The crystals are lonq; needles, slightly flexible and transparent, and having a specific gravity of 1-23, at (55°|. The taste of caffein is very weak, but bitter and disagreeable. It is soluble, according to Pfaff, in 50 times its weight of cold water ; but it is much more soluble in boiling water, and the solution, on cooling, deposits crys- tals, or rather is converted into a crystalline magma. It is not very soluble in absolute alcohol, but dissolves very well in spirits, of the specific gravity 0*837. Neither ether nor oil of turpentine are solvents of it. Neither acids nor alkalies produce any alteration on it, or • Phil. Magazine, xii. 3o0. Chenevix's substance must have been caffeic acid, f Muterialien zur l'l]ytologie. J Schweigger Siedel's Jour. 1. 487. $ Jour, de Pliartnaoic, xii. 2"2(). Ibid. t Ibid. p. 234. CAFFEIN. 759 combine with it. Nitric acid does not decompose it, and when the acid is evaporated from crystals of caffein, they remain unaltered. When mixed with salts of the peroxide of iron, and black oxide of copper, it does not strike the green colour produced by the extract of coffee, and which Chenevix considered as characteristic of his caffein. It is neither precipitated by the acetate nor diacetate of lead. When heated it melts easily into a transparent liquid, and if the heat be augmented, it sublimes in needles similar to those of benzoic acid. From a red hot platinum spoon it is volatilized without giving out any smell of ammonia or empyreumatic oil. We have four analyses of catfein, all differing so much from each other, that they cannot have been made upon the pure substance. It will be sufficient to give that of Liebig, which, being the latest, and made with great care, is undoubtedly the most accurate. He obtained Carbon 49"31 or 4 atoms = 3 or per cent. 49*49 Hydrogen 5-28 or 2^ atoms = 0-3125 — — 5-16 Azote 28-75 or T atom = 1-75 — — 28-86 .. Oxygen 16-66 or 1 atom =1-00 — — 16-49 100-00* 6-0625 100 It contains besides half an atom of water, which may be driven off by heat. Liebig considers it as a compound of cyanic acid (con- taining half its usual dose of oxygen) and half an atom of ether. This supposition agrees very well with the atomic constituents. MM. Kobiquet and Boutron have lately found the quantities of caffein in 100 parts of different varieties of coffee, as follows : — f Caffein. 6-4 4-4 Martinique coffee Alexandria coffee Java coffee Mocha coffee Cayenne coffee . St Dominsfo coffee 4-4 4-0 3-8 3-2t * Annalen der Pharmacie, i. 17. He found that 938 parts of dry caffein gave 1696 parts by weight of carbonic acid, and 446 water. The volume of azotic gas was to that of the carbonic acid gas given out, when the caffein was decom- posed by oxide of copper, as 1 to 4. Hence the numbers in the text, f Jour, de Pharmacie, xxiii. 109. J Since the imperfect account of theina, given in page 295 of this volume, was printed, I have seen the analysis of it by M. Jobst ofStutgard, from which it ap- pears to be identical in its composition and ciiaracters with caft'cin.* He prepared it by boiling tea leaves in water, filtering and concentrating the solution, and then mixing it with acetate of lead, till all precipitation was at an end. He then filtered and threw down the excess of lead by sulphuretted hydro- gen. Being now concentrated sufliciently, in was deposited in soft needles, which were purified by solution in alcohol. It is snow-white, and in Hue needles, having a silky lustre. Does not act on vegetable blues. Much more soluble in hot than in cold water, alcohol, and ether. Dissolves readily in acids, and is decomposed when heated with sulphuric * Annalen der Pharmacie, xxv, C3, 760 NEUTRAL COMPOUNDS. SECTION III. — OF PIPERIN. M. Orstedt first announced, in 1819, the existence of a peculiar principle in the fruit of piper nigrum, or black pepper,* to which he gave the name oi piperin. In 1821 an elaborate analysis of black pepper was made by Pellotier, who also obtained piperin, and de- scribed its properties.t In 1832 an analysis of it was published by Liebig.J It "la^y be obtained by the following process : — Boil pepper in alcohol. Distil off the alcohol, and wash the dry residue with water. What remains undissolved by the water is to be dissolved in hot alcohol. Set the solution aside for a few days, that it may have time to deposit crystals. These crystals may be free.d from a greenish-white resin, by washing them in water, and dissolving them in alcohol, and crystallizing from the solution. It crystallizes in oblique four-sided prisms, whose faces Jire in- clined to each other at angles of about 85° and 95°. When heated to about 212°, it melts into a light yellow transparent oil, which hardens, on cooling, into a light yellow, translucent, resinous-like matter. It has very little taste, and that little is probably derived from some oil of pepper, from which it is very difficult to free it completely. It is insoluble in cold, and but slightly soluble in boil- ing water. It is very soluble in alcohol ; less so in ether t but it dissolves better in these liquids while hot than while cold. Acetic acid is also a good solvent of it. Dilute sulphuric, nitric, and muriatic acids do not act sensibly on it. But when these acids are concen- trated, they alter its nature. Concentrated sulphuric acid gives it a blood-red colour ; but the colour disappears if the acid be diluted with water. Muriatic acid acts in the same way, except that the colour produced is not red, but an intense yellow. Nitric acid renders it first greenish-yellow, then orange, and at last red. By long-continued action, oxalic acid and a bitter matter are formed. When piperin is distilled, it produces water, acetic acid, oil, and carburetted hydrogen gas ; but no ammonia. Its constituents,as determined by the analysis of Liebig,§ are or nitric acid. It is not precipitated from its acid solutions by allcalies. When boiled with concentrated potash ley it is decomposed, and ammonia disengaged. It may be sublimed, and contains water of crystallization, which it loses at 212". According to the analysis of Jobst, thcina is composed of Carbon 49'60 Hydrogen 5'22 Azote 28-91 Oxygen 16-27 10000 Numbers almost identical with those obtained by Liebig from catlein. It is clear, that neither theina nor cafFoin constitutes the principle to which tea and coffee are indebted for their peculiar properties. * Jour, de Pliys. xc. iT.i. f Ann. de Chim. et de Phys. xvi. 337. J Ibid. li. 441. § Ann den der Pharmacie, vi. .S6. DAPHNIN. 761 peculiar vhich he of black and de- ished by 1 the dry ter is to ■ew days, 3 may be ater, and tion. s are in- en heated jil, which inous-like y derived to free it le in boil- t dissolves ;ic acid is i muriatic re concen- sid gives it be diluted pt that the Citric acid t red. By e formed, id, oil, and ig,§ are ilics. When disengaged. )ses at 212°. •2 II 17 Carbon 09*78 or 40 atoms = 30 or per cent. 70*58 Hydrogen 6*69 or 22 atoms = 2*75 — — G-4S Azote 4*10 or 1 atom = 1*75 — — 4*12 Oxygen 19*43 or 8 atoms = 8*00 — — 18*82 )0 n. to which tea 100*00 42*50 100 If we abstract 2 atoms of water, we have the formula for piperiii, (2*0 JJ20 ^j5 Qo Now, this corresponds with the constitution of narcotin ; only, it contains but half the number of atoms of oxygen. SECTION IV. OF DAPHNIN. Vauquelin made some experiments on the bark of the daphne nlpina* and extracted an acrid volatile substance, soluble in water, to which Berzelius has given the name of dapHnin. In the year 1822, MM. C. G. Gmelin and Baer published an elaborate set of experiments on the bark of the daphne mezeriwn, or common mezerion, so frequent in our shrubberies, in consequence of the beauty and early appearance of its blossoras.t Among many other constituents of this acrid bark, they discovered a crystallized body, which they examined, and to which they gave the name of daphnin. We shall apply this name to the substance described by these che- mists, as the nature of Vauquelin's principle still remains uncer- tain. Gmelin and Baer obtained the daphnin in the following way : — The alcoholic solution of the bark was mixed with water, and the alcohol distilled off, and the residual liquid was precipitated by acetate of lead. The precipitate thus obtained was washed with cold water, and decomposed by a current of sulphuretted hydrogen gas, and the liquid filtered and evaporated to dryness. The residual matter was digested in cold absolute alcohol, and the alcoholic so- lution left to spontaneous evaporation. The daphnin was deposited in small crystals, while malic acid and brown colouring matter re- mained dissolved in the residual liquid. Gmelin found that daphnin existed also, and in greater quantity, in the bark of the daphne alpina. Daphnin thus obtained is but little soluble in cold water, but very soluble in boiling water ; and, as the liquid cools, it is deposited in colourless crystals, having a bitter and slightly-astringent taste. It is soluble in alcohol and ether. The solutions are coloured yellow by alkalies ; but the colour disappears when the alkali is saturated with an acid. According to Gmelin and Baer, daphnin is neither acid nor al- kaline, and they consider it as analogous to asparagin. Nitric acid converts it into oxalic acid. Acetate of lead does not precipitate pure daj)hnin from its solutions, but a partial precipitation takes place when the solutions contain a mixture of foreign matter. When heated in a retort it melts, then swells up, and becomes 'I. II 1 \ ,s. xvi. 337. vi. no. * Ann. de Chim. Ixxxiv. 17.3. \ Schwoiggcr'n .Tour. xxxv. 1. 762 NEUTRAL COMPOUNDS. I black, and gives out an acid vapour. When thrown upon red hot charcoal it exhales a pungent vapour. No attempts have been made to ascertain the ultimate constitu- ents of this substance, nor to determine its action upon the animal economy. SECTION V OF JALAPPIN. This substance was first obtained by Mr Hume in 1824,* by the following process : — Jalap, which is the root of the convolvulus Jalappa, is powdered and macerated for a couple of weeks in weak acetic acid. A dark- coloured solution is obtained, which is filtered, mixed with caustic ammonia, and well agitated. A gritty powder falls, consisting of small crystalline grains, which is to be washed in cold water. Being again dissolved in acetic acid, and thrown down by ammonia, it is obtained in small needles. Jalappin thus obtained has a snow-white colour, but is destitute of taste and smell. It is insoluble in cold, and but little soluble in boiling water. It dissolves readily in alcohol, but is insoluble in ether. An ounce of jalap yields about 5 grains of this substance. How far this jalappin of Hume constitutes the principle to which that root owes its peculiar medical properties, is doubtful. Schweins- berg assures us that it is nothing else than ammonia — phosphate of magnesia mixed with some lime and organic matter. Herberger states that when the resin of jalap is dissolved in al- cohol, and mixed with an alcoholic solution of acetate of lead, a precipitate falls, consisting of oxide of lead united to resin, which acts the part of an acid. When the residual liquid is freed from lead and acetic acid, it yields a transparent colourless resin, which is very soluble in alcohol. To this substance M. Herberger has given the name oi jalappin. Concentrated acetic acid dissolves it completely, especially when assisted by heat. It is soluble also in sulphuric, nitric, phosphoric, and muriatic acids.f We do not know whether these two substances be identical, but it is probable that they are. SECTION VI OF SINAPIN. MM. Henry and Garot,t extracted a substance from the seeds of sinapis alba and nigra, to which they gave the name of siilpliosina- pisin, a name afterwards shortened into sinapin. It may be obtained by the following process : — Subject mustard seeds to pressure, to separate from them their fixed oil. Boil the residual matter with water, and evaporate the decoction on the water-bath to the consistence of honey. Mix this residue with 6 or 8 times its volume of absolute alcohol to precipi- tate the gum, mucilage, colouring matter, and the acetate, citrate, * Medical and Thys. Jour, for 1824, p. 246. f Bcrzeliuij, Traite de Chimie, v. 52G. f Jour, de Pharmacie, xvii. 1. COUMAUIN. 763 on red hot B constitu- the animal J4,* by the s powdered i. A dark- vith caustic insisting of iter. Being imonia, it is is destitute le soluble in insoluble in substance, iple to which i. Schweins- phosphate of isolved in al- ;e of lead, a resin, which is freed from resin, which e oijalappin. pecially when phosphoric, identical, but m the seeds of of sulphosina- lay be obtained rem them their evanorate the oey. Mix this >hol to precipi- icetate, citrate, and phosphate of lime. Distil the alcoholic solution, and leave the syrupy residue in a state of rest. It gradually deposits abundance of crystals of sinapin. Separate the mother water, and concen- trate it to obtain an additional quantity of sinapin. Dissolve the sinapin repeatedly iq alcohol, and crystallize in order to obtain it in a state of purity. Sinapin thus obtained possesses the following properties : — It is white, very bulky and liglit. Its taste is at first bitter, and then analogous to that of mustard. It dissolves with a yellow colour in water and alcohol, and if it be dissolved in these liquids while hot, it crystallizes when tliey cool. The crystals are small needles grouped together in bundles. It crystallizes from an acid solution preserving its original properties. It \a perfectly neutral. When distilled it gives out ammonia, partly combined with carbonic acid, and partly with sulphuretted hydrogen. When the solution of sinapin is mixed with chlorine, it assumes a brown colour, sulphuric acid is formed, and the smell of hydrocy- anic acid becomes evident. When we distil sinapin with sulphuric or phosphoric acid and water, we obtain in the receiver an acid liquor, which strikes a red with the persalts of iron, and produces a white precipitate in a solution of sulphate of copper containing iron ; showing the presence of hydrosulphocyanic acid in the liquid. Nitric acid dissolves sinapin, and assumes a deep-red colour, nitrous gas is disengaged and sulphuric acid formed. Muriatic acid gives sinapin a green colour, and when heat is applied, hydrocyanic acid is disengaged. The solution of sinapin in potash assumes at first a deep-yellow colour, and then becomes green. Acids dropt into this solution or into that of sinapin in an alkaline earth precipitate the greatest part of the sinapin unaltered. It is obtained in the same state by eva- porating the ammoniacal solution of it. But when wo heat mixtures of dry sinapin, and salifiable bases, a sulphocyanet is fprmed. Sinapin throws down a cheesy precipitate from nitrate of silver. If we precipitate a solution of nitrate of silver as exactly as possible by sinapin, and then decompose by sulphuretted hydrogen the excess of the silver salt in the liquid, and saturate the nitric acid exactly with potash, and evaporate the liquid, a green-coloured organic substance is obtained. According to Henry and Garot, sinapin is composed of Carbon 57-920 or 24 atoms = 18 Hydrogen 7-795 or 22 atoms = 2-75 Azote 4-940 or 1 atom = 1-75 Sulphur 9-G57 or 2 atoms = 4 Oxygen 19-688 or 7 atoms = 7 100-000 33-5 armacie , xvii. 1- SECTION VII. OF COUMARIN. In the year 1820, M. Vogel announced that Tonka bean, which ^• 'J 'M •y\T: a. ■ I •■xm. V m. n •64 NKUTIIAL COMPOUNDS. !i 1 .iil is the fruit of the coumaronna oderata, contained benzoic acid.* The resemblance between the smell of the Tonka bean and the flowers of the mdilotiis officinalis led him to examine those flowers also, and ho assures us that he found the same acid in them. Soon after M. Guibourt ascertained that the crystalline matter in the Tonka bean was not benzoic acid, but a peculiar substance which he distinguished by the name of coiiinarin. In 1825, MM. Boullay and Boutron-Charlard published a chemical examination of the Tonka boan,t in which they confirmed the accuracy of M. Guibourt's statements, and adopted the name coumarin^ to distinguish that substance. Still more lately, MM. Chevallier and Thubeuf announced}: that in the water distilled from the melilot, they had found a peculiar crystallized substance, which in their opinion possessed alkaline characters. This announcemf nt induced M. Guilleraette to make a set of experiments on the subject. § The tops of the flowers of melilot, reduced to a coarse powder, were treated with alcohol of 0*842 till they ceased to communicate any colour to that liquid. The tinctures were mixed together, and the alcohol distilled oft*. The residue, put into a porcelain capsule, and left at rest for twenty-four hours, became covered with a layer of half solid fatty matter, which was carefully removed. The liquid was then eva- porated to the consistence of a syrup, and left at rest for forty-eight hours. A number of crystalline needles were deposited which were thrown on a cloth and washed with cold water. The mother water when concentrated yielded more of these crystals. These crystals were dissolved in water and treated with animal charcoal. Being now crystallized again they were in a state of purity. These crystals thus obtained are identical with the coumarin from the Tonka bean. The crystals are either silky needles or short prisms. The taste is sharp, but leaves an agreeable impression in the mouth. Cou- marin is heavier than water. It melts in a very gentle heat, and crystallizes again confusedly when allowed to cool. It sublimes very easily, and crystallizes in needles. It is not sensibly soluble in cold water. Boiling water dissolves it readily and allows it to crystallize on cooling. When we add to water more coumarin than it is capable of dissolving, the excess melts and forms an apparently oily stratum at the bottom of the vessel. When distilled along with water, the liquid that comes over possesses the characters of common melilot water. Alcohol and ether dissolve coumarin at the ordinary temperature of the atmosphere. And it is easily obtained in crystals by leaving these solutions to spontaneous evaporation. Diacetote of lead throws down a copious wliite precipitate. Neither ammonia nor caustic potash dissolve it. At the common temperature of the at- mosphere both sulphuric and nitric acids dissolve a great quantity * Jour, de Pharmacie, vi. 805. X Jour, de Chim. Mod. x. .350. t Il)id. xi. 480. <5 Jour. (Ic Phannacip, xxi. 172. IlKSrKKIDIN. 76fl oic acid.* n ami the »se flowers m. Soon ;ter in the :e which he Si. BouUay ion of the Guibourt's lijuish that uncedj that a peculiar ed allcaline tte to n\ake lowder, were unicate any her, and the (Side, and left r of half solid rvas then cva- ir forty-eight I which were nother water hese crystals ;oal. Being ity. These rin from the The taste louth. Cou- tie heat, and sublimes very ater dissolves en we add to g, the excess )ottom of the at comes over J temperature als by leavin^f etote of lead ammonia nor Durc of the at- great quantity 1. xi. 480. ;ip, xxi. 17-2. of coumarin, without altering its nature. These solutions are pre- cipitated by water. The dissolvhig power of these acids >' •.nishes with their concentration. When nitric acid is assisted b) .leat, it gives coumarin a yellow colour, but no oxalic acid is formed. Phos- phoric, tartaric, and acetic acids dissolve it more or less. The same acids, diluted with a great deal of water, dissolve it when hot ; but no combination takes place, and the coumarin crystallizes when the solution cools. Coumarin was analyzed by M. Henry, who obtained Carbon 70-40 or 10 atoms = 7-5 or per cent. 75*98 Hydrogen 3-89 or 3 atoms = 0-375 — — 3-78 Oxygen 19-71 or 2 atoms =2-0 — — 20-24 100-00 9-875 100-00 The identity of coumarin and the crystals from melilot has been established. Ii neither possesses the alkaline qualities ascribed to it by C'hevallier and Thubeuf, nor the acid qualities given it by Vogel ; but appears to be a neutral substance. SECTION VIII OF HESl'ERIDIN. This substance was discovered by M. Lebreton, in 1828, in the unripe fruits of different species of orange and lemon trees.* To obtain it we must take unripe oranges after they have obtained a diameter of about half an inch. The white portion of the rhind is freed from the outer green covering, and from the innermost part of the fruit. It is then digested in water, of a temperature between 75° and 80° ; the liquid is filtered and concentrated to ,^^ths of its original bulk. A little albumen precipitates which must be separ- ated. The malic acid which the li([uid contains must now be satu- rated with lime, and the whole evaporated to the consistence of a syrup. This syrup being digested in alcohol of the specific gravity 0-8 1 7, gum, albumen, a brown bitter matter, and malatc of lime are left undissolved. The solution being filtered and evaporated to dryness, the granular extract remaining is to be mixed with 20 times its weight of water, or distilled vinegar, and often agitated. This clear liquid being drawn off and left undisturbed for eight days, the hesperidin is deposited in small crystals, which must be carefully washed. T^^e distilled vinegar deposits the hesperidin much more rapidly than ivater, and is therefore to be preferred as a solvent. Hesperidin, thus obtained, has the form of soft silky needles, without smell, and at first ai)pearing tasteless ; but leaving a bitter impression in the mouth. It melts when heated a little above the temperature of 212°, and while in fusion has the aspect of a resin ; on becoming solid it preserves its transparence, assumes a yellowish colour, and becomes electric when rubbed. It is no longer crystal- lizable, and its taste is sweetish and bitter. At a somewhat higher temperature, hesperidin is completely decomposed. • Jour, dc I'harinacio, xiv. Sll. Ilk- 166 NKUTUAL CO.MrOUNDS. ■t'i i i: I: It is little soluble in cold water ; but boiling water dissolves about ^'jjtli of its wein:lit of it. It is not more soluble in cold alcohol; but boiling alcohol dissolves it much more abundantly, and when the solution cools, a portion of the hesperidin is deposited. It is insoluble in ether, in fixed and in volatile oils. It has no action on litmus paper. The dilute acids do not dissolve it. Concentrated sulphuric acid gives it a red colour. Concentrated acetic acid dis- solves a small quantity of it, which crystallizes when we evaporate the acid. It is soluble in the alkaline leys. Diacetate of lead does not throw it down. When the aqueous solution of it is mixed with the sulphnted ])eroxidc of iron, a brownish-red precipitate f[ills. M. Widnmann, of Munich, obtained from the rhinds of unripe oranges a substance diifering from the hosi)eridin of Lebreton. It was crystallized in ])risms, insoluble in alcohol, soluble in water, and not forming oxalic acid when acted on by nitric acid.* SECTION IX. — OF I'OrULIN. This principle was discovered in 1830 by Bruconnotj in the bark of the popidus iremnla,\ where it is accomj)aiiied by salicin. He found afterwards, that the leaves of the tree furnish it in greater abundance. It may be extracted by the following process : — Boil the leaves in water, and pour diacetate of lead into the de- coction. A fine yellow precipitate falls. B^ilter the liquid and evaporate it to the consistence of a syrup. When it cools, the populin separates under the form of a very bulky crystalline preci- pitate. Subject it to strong press r, e between folds of linen cloth, then heat it with IGO times its weight of water, and a portion of ivory black, and filter the liquid while boiling hot. On cooling it deposits abundance of populin in fine silky needles. When dried on blotting paper it is a very light substance, having a snow-white colour. Populin has a sweet taste, not unlike that of liquorice. It re- quires about 2000 times its weight of cold water to dissolve it ; but it dissolves in about 70 times its weight of boiling water. It is not affected by the greater number of the metalline salts. But chloride of sodium throws it down unchanged, and in the form of crystals. Boiling alcohol dissolves it very well, and when the liquid cools the populin is deposited in such abundance as to convert the whole liquid into a crystalline magma. It is very soluble in acetic acid, and nitric acid, and it may be precipitated from these solutions by the alkalies. Phosphoric acid dissolves it also ; but when that acid is too concentrated, it converts it at once into a resin. The weak mineral acids when hot act upon it as they do on salicin : they convert it into a white resinous pow- der, quite similar to that produced from salicin. Like salicin, it gives a purple-red solution with concentrated sulphuric acid. When treated with nitric acid it furnishes, as is the case also with * Jour, de Pharmacie, xvi. 707, t Ann. dc Cliiin. et dc Phys. xliv. 290. PLUMUAOIN. 7(J7 Ives about 1 alcohol; and when cd. It 13 ) action on ncentrated ic acid dis- evaporate )f lead does mixed with te falls. 5 of unripe breton. It 1 water, and , in the bark salicin. He t in greater less : — into the de- 3 liquid and it cools, the jtalline preci- f linen cloth, a portion of 3n cooling it When dried a snow-white )rice. It re- ssolve it ; but er. It is not But chloride m of crystals, quid cools the ert the whole ind it may be losphoric acid ed, it converts hot act upon resinous pow- ,ike salicin, it ic acid. case also with a salicin, a great quantity of carba/otic acid, but no oxalic acid. When heated sufticiently with potash, it ia converted into oxalic acid, as is the case with almost all organized bodies. When heated it first melts into a transparent and colourless licpiid ; it then burns with a strong flame, giving out at the same time an aromatic odour. When distilled, it seems to yield an empyreumatic oil, and benzoic acid. Chlorine and iodine have no marked action on populin. The febrifuge virtues of this substance have not been triinl ; but it is probable, from its great resemblance to salicin, that it is not desti- tute of them. SECTION X. OF l'LUMHA>8"lphuret of carbon (^2. 2 sulphur . we c* Ar' S* c C Az' ^ There will remain . . , or half n\ atom of inellon. If we iicat mellon in dry chlorine gas, we obtain a white product, having a pungent smell, and acting strongly on the eyes. The same substance seems to bo formed when we heat together, 2 parts of corrosive sublimate, and 1 part of sulphocyunodido of potassium. The two substances when slightly heated, m(>lt, act violently on each other, swell up, and bisulphuret of carbon is dispngaged. When mellon is heated with potassium, a combination takes placo with the evolution of light. The product is a transparent mass, easily fusible. It dissolves in water, and the solution has the flavour of bitter almonds ; but contains no trace of oxalate or cyanodido. It precipitates the metals ; but the precipitates have no resemblance to cyanodides. The aqueous solution is decomposed by the addition of an acid. A bulky precipitate falls in white flocks, which is readily soluble in an excess of alkali. At the instant of the combination of mellon with potassium, a slight smell of ammonia is perceptible. This doubtless is occasioned by the hydrogen of a trace of naphtha not removed from the potassium. Liebig endeavoured to obtain mellon in large quantities by deconi- f losing sulpho-cyanodide of potassium, by means of chlorine. If we leat this sulphocyanodide above its point of fusion in a current of dry chlorine gas, a violent decomposition takes place all at once. Thick red vapours are disengaged, which are deposited in red leaves on the walls of the retort. We obtain in this way, for volatile pro- ducts, chloride of sulphur, and the chloride of cyanogea discovered by Serullas. At a gentle heat, which ought not to exceed the point at which the sulphocyanodide of potassium melts, there distils over chloride of sulphur, accompanied by another product, and at the end of the distillation, chloride of cyanogenis deposited in long needles, in the neck of the retort. The residue cc/ntained in the retort presents, when wc separate it by washing with water, from chloride of potassium with which it is mixed, a substance of a light-yellow colour, which, when dry is a light powder. This substance, after exposure to a red heat, is pure mellon. Mellon, when heated in a solution of hydrate of potash, dissolves with the evolution of ammonia. During the solution, there is formed a great number of long silky transparent crystals, which on cooling increase so as to fill the whole liquid. The evolution of ammonia shows that the substance which combines with the potash, contains less azote than mellon does. Mellon dissolves likewise in nitric acid. During the boiling, we 3d m I:' \i X 't :i I ! I 770 SOME COMPOUNDS OF AZOTE. observe a continual effervescence without the disengagement of nitrous gas. There is formed in the liquid, which is very acid, and which contains ammonia, a peculiar acid in long needles. This is cyanilic acid. It has been described in this work, in page 211. Leopold Gmelin, during the preparation of sulphocyanate of potash, obtained occasionally a small quantity of a peculiar salt. When the mixture of prussiate of potash and sulphur was heated above the point at which it ceases to strike a blue with the salts of iron, then dissolved in water, the iron precipitated by potash, and the residue boiled in alcohol, and the filtered solution set aside for some time in a cold place, cauliflower-shaped crystals of this peculiar salt are deposited. These crystals were i-edissolved in water, crys- tallized a second time, and pressed between folds of blotting paper. Being now washed with hot alcohol, till they ceased to give a red colour to the persalts of iron, the salt was freed from the sulpho- cyanate of potash, with which it had been originally mixed. To the acid contained in this salt, M. L. Gmelin has given the name of hydromelonic* This acid may be obtained in the following manner : — The hot solution of the salt is decomposed by concentrated acetic acid, which throws down a white flocky precipitate. To obtain the whole acid, the mixture is evaporated to dryness, the acetate of potash is re- moved by alcohol, and the acid remains on the filter. Hydromelonic acid, thus obtained, is a white earthy powder, destitute of taste and smell. When dissolved in boiling water, it scarcely reddens litmus paper. When heated in a glass tube, over a spirit lamp, it effervesces slightly, and is converted into a lemon-yellow matter (Mellon), which by continuing the heat is entirely dissipated. There passes over, first a watery vapour, then a great deal of hydrocyanate of ammonia, Avhich concretes on the upper part of the tube, while on the lower part, a white opaque body is deposited, which, by continuing the heat, is converted into an aqueous solution of potasli. The acid dissolves easily and abundantly in nitric acid. When diluted with water, the solution becomes milky. The nitric acid may be evaporated away, leaving the hydromelonic acid unaltered. Sulphuric acid dissolves it, though more slowly, and the solution becomes muddy when water is added. It is but slightly soluble in cold, but more so in boiling water. When this last solution is allowed to cool, most of the acid is preci- pitated. Alcohol acts like water, except that it takes up less of the acid. To analyze this acid, Gmelin employed hydroraelonate of lead, dried in the open air at 60°, 100 parts of this salt exposed to a heat of 212°, lost 11*087 parts of water, and when the heat was raised to 248°, it underwent an additional loss of 3'043, making the whole water disengaged, 14*13 parts. * Ann. der Pharm. xv. 252. MELLON. 771 ;agenient of ary acid, and ;s. This is age 211. locyanate of jeculiar salt, p was heated 1 the salts of \f potash, and set aside for F this peculiar n water, crys- lotting paper, to give a red n the sulpho- if mixed. To Lven the name er : The hot itic acid, which he whole acid, f potash is re- jarthy powder, jiling water, it ,, it effervesces Mellon), which re passes over, ite of ammonia, on the lower continuing the ic acid. When _he nitric acid acid unaltered, md the solution boiling water, le acid is preci- ;s up less of the ate of lead, dried led to a heat of it was raised to aking the whole 1 00 parts of the same salt being decomposed by sulphuric acid, left ')2-38 of sulphate of lead, equivalent to 45'964 of oxide of lead. Hence the constituents of the salt were Hydromelonic acid 39 906 or 12*154 Oxide of lead . 45-964 or 14 Water . . , 14-130 100-000 This analysis gives us the atomic weight of hydromelonic acid 12-154. Leopold Gmelin analyzed hydromelonate of lead by means of oxide of copper, and obtained Oxide of lead 45-964 or 1 atom =14 Carbon 14-720 or 6 atoms = Hydrogen 2-037 or 5 atoms = Azote 23-010 or 4 atoms = Oxygen 14-269 or 4 atoms = 14 or per cent. 46-46 4-5 14-94 0-625 — __ 2-08 70 23-24 4 — 13-28 100-000 30-125 100-00 But a considerable portion of the oxygen and hydrogen was in the state of water, obviously 4 atoms, of which 3 were driven off by the water bath, and 1 at the temperature of 248°. Subtracting these 4 atoms, and the atom of oxide of lead, the hydromelonic acid is obviously composed of 6 atoms carbon . . . =4-5 4 atoms azote . . . =7 1 atom hydrogen . . =0*125 11-625 So that its true atomic weight is 11-625, and it is composed of an atom of mellon, and an atom of hydrogen. The hydromelonate of potash, discovered by L. Gmelin, is a ycllowish-wliite opaque cohesive mass, having a bitter taste. When heated, it gives out carbonate and hydrocyanate of ammonia, and melts into a clear yellow liquid, which concretes on cooling. When heated with nitric acid, it froths, but without any efferves- cence. It dissolves in hot sulphuric acid, and is precipitated again by water. It is scarcely soluble in cold, but very soluble in hot ' ater. Alcohol scarcely acts upon it, even at a boiling temperature. It is decomposed by all the stronger acids, the hydromelonic acid being disengaged. The earthy alkaline salts, earths, and most of the metallic salts, occasion a precipitate in hydromelonate of potash, of flocks most commonly white, but the oxide of chromium salts, give a bluish-white, those of peroxide of iron, a light-brown, those of oxide of cobalt, rose red, of nickel oxide, bluish-white, of suboxide of copper, lemon yellow, of black oxide of copper, sisken-green, of gold oxide, yellowish- white, and of platinum oxide, brownish-yellow.* ■m m h -f ! i 1 ^ ■ ; i K ■■' . ; •v\\ \ * L. Gmelin, Ann. der Pharmacie, xr. 252. I ^ V II I r i 772 SOME COMPOUNDS OF AZOTE. SECTION III. — OF MELAM.* The preparation of sulphocyanodide of ammonium in a dry state, is attended with difficulties, in consequence of the readiness with which it absorbs moisture from the atmosphere, and runs into a liquid. M. Liebig therefore substituted a mixture of 2 parts sal ammoniac, and 1 part sulphocyanodide of potassium, which, when heated, yield precisely the same volatile products. According to Liebig, sulphocyanodide of ammonia, and urea are composed of the same constituents, namely, C" H* Az" O' (sub- stituting O' for S». When raised to a temperature a few degrees higher than the boiling point of water, it undergoes decomposition, and so much the more completely the slower the temperature is raised. The first effect of the heat is to disengage a notable quantity of ammoniacal gas. After a certain time bisulphuret of carbon ap- pears, and in the neck of the retort a number of crystals of sulphuret of ammonium is collected. The quantity of ammonia disengaged is so great, that all the tisulphuret of carbon (which is under the form of gas) mixes with it, and does not condense on cooling. But if we connect the retort with the refrigerating apparatus, we see, for every bubble of am- monia which condenses, a drop of bisulphuret of carbon fall to the bottom. The bisulphuret of carbon formed during this process amounts to ^th of the sulphocyanodide of potassium employed. During the whole course oi the distillation no permanent gas is disengaged. The sulphocyanodide of ammonium is entirely decora- posed into ammonia, bisulphuret of carbon, sulphuret of carbon, sulphuretted hydrogen, and a new substance, to which M. Liebig, the discoverer, has given the name of melam. T' are remains in the retort this new substance, mixed with chloride of potassium and sal ammoniac, which last had been added in excess. By washing this residue in a sufficient quantity of water, the .raelam may be obtained in a state of purity, l^ielara, when pure, has a grey colour. It is insoluble in water, alcohol, and ether. It contains no sulphur as a constituent, but sometimes sulphur is mechanically mixed with it, when the sulphocyanodide of potassium employed in its preparation has been too strongly heated. But it may be freed from this sulphur by simple levigation, it being mixed with it in the state of a heavy powder. Melam is decomposed by a strong heat ; ammonia is disengaged; a crystalline matter is sublimed in small quantity ; and there re- mains a yellow substance which, at a red heat, is decomposed into cyanogen and azote. If we heat this residue merely till it become yellow, it gives when boiled with potash, the same crystalline substance mentioned, when "treating of melam. By boiling, melam dissolves in hydrate of potash of moderate • Lie- \^, Ann. de China, ot de Phys. Ivi. 16. MELA>;. 773 a dry state, idiness with runs into a 2 parts sal vhich, when md urea are LZ* 0« (sub- ler than the 1 so much the le quantity of of carbon ap- is of sulphuret t, that all the is) mixes with nect the retort bubble of am- bon fall to the cr this process employed, •mancnt gas is mtirely decom- ret of carbon, ich M. Liebig, are remains in potassium and of water, the im, when pure, and ether. It [raes sulphur is ide of potassium heated. But it I, it being mixed la is disengaged; ; and there re- lecomposed into |w, it gives when lentioned, when lash of moderate lo. strength, and by continuing the action we may decompose the melam entirely. But if we filter the liquid before the melam is wholly dissolved, there precipitates a white heavy powder, which is melam in a state of purity. M. Liebig employed this pure melam to determine its composition. He found that, when burnt by means of oxide of copper, the gases evolved were azotic gas, and carbonic acid gas in the proportion :: 11: 12. He obtained from 100 parts of melam 110*2 of carbonic acid, and 35*4 of water. Hence the constituents are. Carbon .... 30-05 Hydrogen . . . . ' 3'93 Azote 66*02 100*00 M. Liebig deduces from these numbers the following atomic consti- tution of melam : — 6 atoms carbon = 4*5 or per cent. 30*64 4^ atoms hydrogen = 0*5625 — — 3*83 5^ atoms azote = 9*625 — — 65*53 14*6875 100*00 The decomposition of melam by the acids is very singular. If we boil it with concentrated nitric acid till it is entirely dissolved, we obtain, when the liquid cools, a quantity of transparent crystals, which possess all the properties of an acid. This acid is the cyanuric* in a state of purity. During this decomposition no nitrous gas is evolved, but ammonia is formed, and found combined with the nitric acid. When melam is fused with hydrate of potash it behaves exactly as with nitric acid only, instead of cyanuric acid, cyanic acid is formed. The mass froths violently, a great quantity of ammonia is disengaged, and if the melam is sufficient m'c obtain neutral cyanate of potash, which fuses with facility. The fused mass is as liquid as water, and, on cooling, assumes the form of a transparent crystalline mass. When melam is boiled with muriatic acid it dissolves completely, and the liquid, besides anmionia, contains another substance, to be noticed afterwards. Dilute sulphuric acid acts like muriatic acid ; but concentrated sulphuric acid forms together with ammonia another product, very similar to the preceding, but differing in its composition and its properties. If we boil melam in a moderately-concentrated solution of potash till it disappears completely, and evaporate the solution, we observe, when the concentration has been carried to a certain point, the * This acid is described in the Chemistry of Inorganic Bodies (vol. ii. p. 225)i under the name of cyanous acid; and in p. 208 of this work under the name ci/anuric acid. It was supposed at first to contain no hydrogen. But was showQ by Wuhlcr and Liebig to contain a iiltlo of that principls. t:^!i <;'< !>- <(t 774 SOME COMPOUNDS OF AZOTE. ' 1 formation of brilliant plates, the quantity of which augments as the liquid cools. The liquid which swims over these crystals retains scarcely a trace of this substance. Neutralized by acids or by an addition of sal ammoniac, it gives a thick white gelatinous precipi- tate. This substance is identical with that formed when melam is treated with muriatic acid. The brilliant crystals constitute the substance called melamin. If we merely add sal ammoniac to the solution without neutraliz- ing it, and then evaporate, long, and very fine needles are deposited. This is the same salt as is obtained when melam, or the yellow sub- stance remaining after the ignition of melam, is treated with potash. It appears from the experiments of Knapp, which were made with great precision, that when melam is dissolved in concentrated nitric acid, it is converted into ammelide and ammonia. Dilute nitric acid forms with it ammelin and melamin. The ammelide is slowly con- verted into cyanuric acid. From 1 atom of amelide C^ H^^ Az^i O' Take li atoms ammonia H'* Az'i Add 3 atoms water C« Az» 0» '[ I We hare 1 atom cyanuric acid = C' H' Az* O"* SECTION IV. — OF MELAMIN.t To prepare this substance, we take the well-washed residue of the distillation of 2 lbs. of sal ammoniac, and 1 lb. of sulphocyano- dide of potassium ; add to it 2 ounces of fused hydrate of potash dissolved in 3 or 4 lbs. of water, and keep the whole in a boiling temperature till the liquid is quite clear, which in general takes place after three days boiling. During the ebullition, the colour of the residue changes to yellowish-white ; the liquid becomes milky, and its consistence increases. The liquid evaporated must be re- placed from time to time, by adding new quantities of solution of potash, of the same strength as that employed at first. When the liquid has become clear, we filter and evaporate at a gentle heat till the brilliant plates begin to appear. We then allow the liquid to cool slowly, wash the crystals and purify them completely by repeated crystallizations. The crystals of pure melamin are octahedrons with rhomboidal bases having angles of about 75° and 105°. They are colourless and have the vitreous lustre. They are not altered by exposure to the air, and contain no water of crystallization. Melamin is very little soluble in cold water ; but boiling water is a better solvent. It is insoluble lu alcohol and ether. When heated the crystals decrepitate and melt into a transparent liquid which concretes on cooling into a crystalline mass. When the heat is * Ana. dti China, et de Fhys. Ixiv. 239 ; or Ann. der Pharmacle, xxi. 241. f Liebij;, ibid. Ivi, 23. 1 \ MELAMIN. 775 ments as the fstals retains iids or by an 10U3 precipi- en melam is anstitute the lut neutraliz- ,re deposited, le yellow sub- l with potash, are made with (titrated nitric ute nitric acid is slowly con- y 0«' bed residue of f sulphocyano- Irate of potash e in a boiling general takes n, the colour of jecomes milky, ^d must be re- of solution of St. When the , gentle heat till he liquid to cool ely by repeated ith rhomboidal y' are colourless by exposure to boiling water is . When heated 'ut liciuid which len the heat is rmacie, xxi. 241. farther increased, the melamln rises along the inside of the tube without subliming. At a red heat it is decomposed, giving out ammonia, and there remains a lemon-yellow residue, which in a still higher temperature is decomposed into cyanogen and azote, without leaving any residue whatever. Melamin combines with all the acids, and forms with them well characterized salts. They all without exception, possess slightly acid characters; but they form also disalts which are perfectly neutral. When it is heated witii a solution of sal-ammoniac, am- monia is disengaged, and the melamin combines with the muriatic acid. The sulphate and nitrate of copper, the salts of zinc, of iron, and of manganese are decomposed by a solution of melamin in water, and the oxides are precipitated. In general it combines with a portion of the acid and base, and forms a double disalt. Melamin contains no oxygen. When fused with potassium, am- monia is disengaged with the appearance of light and a fusible salt formed soluble in water, which possesses the characters of the com- pound formed by means of mellon and potassium under the same circumstances. When melamin is fused with hydrate of potash, cyanate of potash is formed ; if the melamine be in excess, we obtain also mellonet of potassium. When melamin is decomposed by oxide of copper, and the gase- ous products collected, they consist of equal volumes of carbonic acid and azotic gas. M. Liebig found the constituents to be Carbon 28*64 or 6 atoms = 4*5 or per cent. 28*57 Hydrogen 4*82 or 6 atoms = 0*75 — — 4*76 Azote 66*54 or 6 atoms = 10*5 — — 66*67 100*00 15*75 100*00 It is obvious that any equal multiples of 1 atom carbon + 1 atom hydrogen + 1 atom azote would equally correspond with the analysis cf Liebig. The only sure way of determining the true composition is to determine the proportion of this base necessary to saturate an atom of acid. We shall find afterwards that the analysis of oxalate of melamin indicates 15*75 for the atomic weight of melamin. When melamin is strongly heated with concentrated sulphuric acid it is decomposed without becoming black. Ammonia is disen- gaged and a new substance formed which remains in solution in the acid. It is the same substance which is formed when mellon is heated in the same acid. The dilute acids combine with melamin without altering it. For sulphuric acid it has a pretty strong affinity. The presence of even a small quantity of this acid is immediately indicated by a crystal- line precipitate, which is abundant and very little soluble in cold water, but more soluble in hot water, and when the solution cools, this substance crystallizes in fine and short needles. We easily obtain the nitrate of melamin by adding nitric acid to a hot solution of melamin, in water, till the liquid is strongly acid. When the liquid cools, the nitrate of melamin crystallizes in silky li '^'hM , :l I, ;f' :( :■ ill I m \ 11 'M;., if> 776 SOME COMPOUNDS OF AZOTE. I needles, not altered by exposure to the air. They may be dissolved and crystallized a second time without decomposition. When this salt is burnt it gives out carbonic acid and azotic gases, in the pro- portions : : 6 : 7. Showing that it contains 6 atoms of carbon, and 7 of azote. Oxalate of melamin is more soluble in water than the nitrate. When analyzed, it yielded carbonic acid and azotic gases in the proportions : : 8 : 6. Showing the constitution of melamin. The atoms of carbon in the oxalate are 8, and those of azote 6. Be- sides the 6 atoms of carbon in the melamin there arc 2 atoms in the oxalic acid. In the nitrate there are 6 atoms of azote from the melamin, and one atom from the nitric acid making together 7. M. Liebig, analyzed oxalate of melamin, and obtained Carbon 27*63 or 8 atoms =6 or per cent. 28'08 Hydrogen 3'73 or 7 atoms = 0*875 — Azote 48*67 or 6 atoms = 10*5 Oxygen 19*97 or 4 atoms = 4*00 4*09 — — 49*12 _ — 18*71 100*00 Now this is equivalent to 1 atom melamin 1 atom oxalic acid 1 atom water 21*375 100*00 C6 H^ Az« C O' H O \ C» IV Az6 0« The acetate of melamin is very soluble in water, and crystallizes in large flexible rectangular plates. The phosphate of melamin dissolves readily in boiling water. If the solution be concentrate it solidifies on cooling into a white matter composed of concentiic needles. T\\Q formate of melamin is easily soluble and crystallizable. If we add a hot solution of melamin to nitrate of silver, a white crystalline precipitate falls which increases as the liquid cools. It may be crystallized without decomposition. It was analyzed by M. Liebig, and found composed of 1 atom nitric acid . , , 6*75 1 atom melamin . . . 15*75 1 atom oxide of silver . . 14*5 ■!! I 37*0 SECTION V. — OF AMMELIN."^ It was mentioned before, that when melam is dissolved in caustic potash, melamin precipitates in plates, and another substance re- mains in solution. This substance is ammelin. If we saturate the potash with acetic acid, the ammelin falls down. It is precipitated also by carlponic acid, and by carbonate of ammonia. We obtain a very bulky white precipitate, which is not in the least crystalline. * Liebig, Ann. de Chim, et de Pbys. Ivi. 31. «* AMMELIN. 777 e dissolved "When thb in the pro- larbon, and he nitrate, ises in the min. The ne 6. Be- 2 atoms in >te from the ether 7. id . 28-08 4-09 49-12 18-71 100-00 d crystallines ig water. H into a white llizable. silver, a white uid cools. It analyzed by 5 5 ved in caustic substance re- mte saturate the is precipitated We obtain a ast crystalline. If it be washed, and then dissolved in nitric acid, and tl'c solution concentrated, we obtain long four-sided prisms, either white, or having a slight shade of yellow. If we dissolve these crystals in water, acidulated with nitric acid, and precipitate by caustic ammo- nia, or carbonate of ammonia, we obtain ammelin In a state of purity. It has a fine white colour, and when precipitated by ammonia, it has a crystalline texture. It is insoluble In water, alcohol, and ether ; but soluble in the fixed caustic alkalies, and in most of the acids. When heated It gives a crystalline sublimate, and ammonia; it becomes lemt yellow, and if we continue to heat it, decomposi- tion takes place, it being transformed into cyanogen and azote, without leaving any residue. With the acids it behaves as a base ; but 1^% alkaline properties are not so well characterized as those of melamin. With the principal acids it forms salts which crystallize readily, but which are partly decomposed by water. This liquid dissolves an acid compound, and leaves ammelin under the form of a white powder. Ammelin does not decompose the ammoniacal salts by ebullition ; but with many of the other salts it forms double subsalts similar to those of melamin. When ammelin is burnt with oxide of copper, carbonic acid and azotic gases are given off in the proportion : : 6 : 5. M. Liebig analyzed ammelin, by means of oxide of copper, and obtained Carbon 28-064 or 6 atoms = 4-5 or per cent. Hydrogen 3-966 or 5 atoms = 0-625 — — Azote 54-062 or 5 atoms = 8-75 — — Oxygen 13-908 or 2 atoms = 2-00 — — 28-34 3-94 55-11 12-61 100-000 15-875 100-00 Nitrate of ammelin is partially decomposed by water. Hence^ when we wish to crystallize this salt anew, we ought to add to the solution a little nitric acid. Ammelin, or its nitrate, may be dis- solved in concentrated nitric acid, boiled and evaporated without decomposition. But when nitrate of ammelin is heated by itself, It is easily decomposed. We obtain nitric acid, nitrate of ammonia, protoxide of azote and water. There remains a white substance, which dissolves readily in acids, without fc .ling salts with them. Nitrate of ammelin was analyzed by M. Liebig, and found com- posed of 1 atom ammelin . . . 15*875 1 atom nitric acid . . . 6*75 1 atom water . . . 1-125 23-75 Nitrate of ammelin gives, with nitrate of silver, a precipitate of the same nature as that produced, by melamin. It is white, crystal- line, does not lose water when heated, and when burnt with oxide of copper, furnishes carbonic acid and azotic gas, in the same pro- portion as the simple nitrate. I i ! filli||r- mi m 778 SOME COMPOUNDS OF AZOTE. f 1 It was analyzed by Liebij?, who found it composed of 1 atom nitric acid . . . 6*75 1 atom ammelin . . . 15*875 1 atom oxide of silver . . 14*50 37*125 Knowing the composition of melamin and of ammelin, it is easy to explain their formation in the decomposition of melam. 2 atoms melam, and 2 atoms water, became obviously 1 atom melamin, + 1 atom ammelin. For 2 atoms melam . . C C* H" Az" 2 atoms water . . / H* O' 1 atom melamin 1 atom ammelin I C'-' H" Az>' o> c« H« Az« c« H^ Az" 0» C'2 H" Az'i 0« When melam is boiled with muriatic acid, there are formed am- melin and ammonia. 1 atom melam . . C® H^* Az°* 2 atoms water , . IP O* Subtract J? atom ammonia C« H«» Az»* 0=» H'i Az* Remain of ammelin . C« H^ Az» 0=* When dry ammelin and hydrate of potash are fused together, the matter swells much, ammonia is disengaged, together with the vapour of water. When the action is at an end, we have a transparent liquid, very fluid, and which, on cooling, concretes into a crystalline mass. The salt thus formed is pure cyanate of potash. If to the melted potash we add a small excess of ammelin, the salt is quite neutral, and dissolves readily in water. The solution is decomposed by acids in the manner known. By evaporation, ammonia is disengaged, and carbonate of potash re- main«i. It is easy to explain the formation of cyanic acid by the decom- position of ammelin fused with potash. 1 atom of ammelin, and 1 atom of water, are converted into 3 atoms cyanic acid, and 4 atoms ammonia. 1 atom ammelin . C^ H'' N' O* 1 atom water , . H' O Subtract 2 ammonia Remain which make 3 atoms cyanic acid. C6 H6 N« 03 N» 0=" AMMBLIDE. 779 it is easy to I. 2 atoms melamin, + 0« 11 o» 6 5 O* 5 formed am- together- tUo itli the vapour a transparent to a crystalline ' .sh. If to the ,e salt is quite ;r known. By of potash re- by the decom- f ammelin, and lie acid, and 4 o« O SECTION VI. — Of AMMELIDE. If we add alcohol to a solution of mclam or melamin, in concen- trated sulphuric acid, wo obtain a thick white precipitate. Simply washing it with water, frees it from all acid. The sulphuric acid contains ammonia. We obtain the same substance, if we heat nitrate of ammelin till the soft and pasty mass becomes polid. Wo obtain it also by boiling melamin in concentrated nitric acid, till it is en- tirely dissolved. If we boil impure melam in dilute oulphuric acid, it dissolves, and if wo evaporate gently, we obtain crystals of sulphate of am- melin. These, if we continue to concentrate, or if we boil the li(|uid, are redisaolved, and undergo decomposition, the new sub- stance, to which Liebig has given the name of ammelide, is formed, together with a quantity of ammonia. It may be precipitated from its solutions by the alkaline carbonates, or by alcohol. Ammelide is a white powder, which possesses no alkaline proper- ties. It dissolves indeed easily in acids, and we obtain, especially with nitric acid, crystals. But alcohol and water deprive them en- tirely of their acid. Ammelide was analyzed by Liebig, by means of oxide of copper. He obtained carbonic acid and azotic gas in the proportions : : 6 : 4*5. He found the constituents as follows : — Carbon 27*54 or 6 atoms = 4*5 or per cent. 28*24 Hydrogen 3*61 or 4^ atoms = 0-5625 — — 3*53 Azote 47-84 or 4 J atoms = 7*875 — — 49*41 Oxygen 21*01 or 3 atoms = 3*000 — — 18*82 100 15*9375 10000 Or, we might represent the constituents by the following formula, which is much simpler : — 4 atoms carbon . . . =3*0 3 atoms hydrogen . . = 0-375 3 atoms azote . . . = 5*25 2 atomt; oxygen . . . =2*00 10-625 It is obvious that the ratios are the same as in the preceding. M. Knapp,t to determine the constitution of ammelide with as much accuracy as possible, dissolved it in dilute hot nitric acid, and added an excess of hot nitrate of silver. The solution remained clear; but ammonia (not added in excess) threw down a white curdy precipitate, which was ammelide, combined with oxide of silver. It was washed and dried. ~ ' way, it gave Being analvzed in the usual I ,';T'. • Liebig, Ann. de Chim. et de Phys. Ivi. 37. f Ann, de Chim. et de Phys. Ixiv. 248, 780 SOME COMPOUNDS OF AZOTE. Ml 1':^ i, i i i' .' , 1 I I 1 t It ; 1 1 ■i j ' ^iit 1 1 ^;i| M ; i P Silver Carbon . Hydrogen Azote Oxygen . These numbers lead to the following formula :- 45-84 15'40 1*40 26-86 10-50 100-00 1 atom silver 6 atoms carbon 3^ atoms hydrogen 4^ atoms azote 3 atoms oxygen 13-5 or per cent. 46-05 4-5 — — 15-36 0-4375 — — 1-49 7-875 — — 26-86 3 — _ 10-24 29-3125 100 But one of the atoms of oxygen was in combination with the silver. Hence the constituents of ammelide must be 6 atoms carbon . . =4-5 3^ atoms hydrogen . . = 0-4375 4^ atoms azote . . . = 7-875 2 atoms oxygen . . = 2-000 14-7125 So that the atomic weight of ammelide must be 14*7125. The salt, before analysis, was dried in a temperature of 410". Liebig remarks, that in the transformations which melamin un- dergoes, its alkaline properties diminish in proportion as the oxygen with which it enters into combination increases. Something similar may be observed in the vegetable alkaloids. Narcotin, solanin, and some others, whose alkaline properties are not very decided, are distinguished from the strong alkaloids by a greater dose of oxygen. SECTION VII. — OF CHLORIDE OF CYANOGEN.* During the decomposition of sulphocyanodide of potassium, by means of dry chlorine gas, there distils, besides chloride of sulphur, chloride of cyanogen, which, towards the end of the distillation, when the fire is increased, is deposited in the neck of the retort in long transparent needles. Another portion is dissolved in the chloride of sulphur. We obtain altogether from 4 to 5 per cent, of chloride of cyanogen. It is freed from a little chloride of sulphur with which it is mixed, by subliming it in a vessel through which a dry current of chlorine gas is passing. When thus purified, it is in very brilliant needles ani plates, which have a distinct smell of the excrements of mice. This chloride was analyzed by Liebig with great care. To de- termine the quantity of chlorine which it contained, he dissolved the chloride of cyanogen in alcohol, added ammonia to the solution, and boiled it, mixed with a great deal of water, till all the spirit of * Liebig;, Ann. de Chim. et de Piiys. Ivi. 46. CYANAIMIDE, :8ii th the silver. 5 125. ire of 410». 1 melamin un- as the oxygen lething similar 1, solanin, and decided, are ose of oxygen. tN.* potassium, by ide of sulphur, ftillation, when [retort in long |in the chloride t. of chloride of lur with which a dry current [es ancl plates, I care. To de- 1, he dissolved [o the solution, all the spirit of wine was volatilized. He then added an excess of nitric acid, and precipitated by nitrate of silver. 100 parts of chloride of cyanogen gave 230*72 parts of chloride of silver, equivalent to 57*68 of chlorine. Hence chloride of cyf gen is composed of Chlorine . , 57*68 or 1 atom Cyanogen . . 42*32 or 1*01 atom rano- 100*00 Thus Liehig, by this analysis, has confirmed the original determi- nation of Gay-Lussac. , SECTION VIII. — OF CYANAMIDE.* If we sprinkle ammonia on crystallized chloride of cyanogen, and heat gently, it loses its crystalline aspect, and is reduced to a white powder. This substance is slightly soluble in boiling water, and precipitates in white flocks when the liquid cools. We obtain the same substance if we pass ammoniacal gas through chloride of cyanogen in powder, and placed in a horizontal , ibe. At first a mutual decomposition takes place with the disengagement of heat. Towards the end of the process we must apply heat to render the dev'omposition complete. We obtain a white powder with a slight shade of yellow, which may be completely freed from sal ammoniac by washing it in cold water. This substance is cyanamide. It contains chlorine, which cannot be separated by water, nor by boiling with caustic ammonia. When it is heated, a crystalline substance sublimes, containing all the chlorine, and there remains a lemon-yellow residue, which is decomposed at a red heat into cyanogen and azote. The action of cyanamide on caustic potash is remarkable. It dissolves with difficulty, but with the disengagement of ammonia. If we saturate the clear solution with acetic acid, no cyanurate of potash crystallizes, as one would have it expected to do ; but there precipitates a substance in white flocks, which, as is evident from the disengagement of ammonia, must differ in its composition from cyanamide. When cyanamide is burnt with oxide of copper, it gives a mixture of carbonic acid and azotic gas in the proportion : : 5 : 4. Liebig found farther, that 527 parts of cyanamide furnished, when decomposed by oxide of copper, 156 parts water, and 551 parts of carbonic acid. From these data it is easy to determine the quantity of carbon, hydrogen, and azote contained in 100 parts of cyanamide. What is wanting to complete the 100 parts is, of course, chlorine. But if we calculate from these data, we obviously obtain nothing else than a mixture of two diflVsrent substances. When cyanamide was heated to 244° in a glass vessel, the inside of the vessel became covered with brilliant crystals destitute of • Liebig, Ann. de China, et de Phys. Ivi, 51. ■iV,'. \\ 782 SOME COMPOCNDS OF AZOTK. ■^ > f smell, although the cyanainidc itself did not npucar volatile. I/ichig tiiiiiks it not unlikely that the oyananiidc, sucn as ho analyzed it, was a mixture or a compound of 1 atom cyanamiue . . . C* II* Az* 1 atom cliloride of eyanogen . C^ Az Chi Making . . . . C« li* A/.' Chi For this last is the formula dedueihle from the analysis made hy Lichig. SECTION IX.- -or Tnn potash salt.* When melani, ainmelin, ai.imelide, and cyanaiuido, arc lioatcd to redness, they undergo decomposition, and a lemon-yellow substance remains, which dissolves completely wiu>n boiled in potash. When this solution is evaporated, it coiu-retes into a crystalline mass, composed of long and very fine needles. We obtain the sami; salt of potash, if we dissolve, in a solution of potash, mellon, or the yellow substance which results from the decomposition of sulphoey- anodide of potassium by chlorine. By repeated crystallizations, this salt may be obtained in colour- less cr\ stals. It is very scduble in water, but insoluble in ideohol. So that if we mix the aqneoua solution with its own bulk of alcohol, the salt is precijiitated in small white needles. This salt jjossesses strongly marked alkaline properties. It con- tains water of crystallization, melts when heated, gives out ammonia, without blackening, and leaves pure eyanate of })otash. When dis- solved in water, if wo add some drops of acetic acid, and then chloride of barium, there is formed immediately, or very soon, a crystalline precipitate in fine needles of supereyanurate of barytes. If we dissolve it iu concentrated muriatic or nitric acid, we obtain, on cooling, a number of crystals of pure cyanuric acid. If we expose a dilute solution of the salt to the air, so that it may absorb carbonic acid, or if we noutraliae it cautiously, a white precipitate falls, and the filtered licpiid contains cyanurate of potash. We see that the yellow substance, when boiled with potash, gives the same products as when treated with nitric acid ; namely, cyan- uric or cyanilie acid. But there is formed, at the same time, a small quantity of another salt, which conceals the existence of the cyanurate by mixing with it. M. Liebig has analyzed this salt with care, and has concluded, from his experiments, that it is a mixture of two combinations in very ditfereut proportions. He obtained Carbon . . 33*73 or 5 atoms Hydrogen . . I'll or I atom Azote . . . 42*98 or 3 atoms Oxygen . . 22*18 or 2-h atoms 100*00 * Llcbig', Ann. de Cliim. et de Phys. Ivi. 5^. NITIlOSULIMlUniC ACID. 783 nalyzed it, Chi Chi 518 ma tie by re licnted tr> )\v substance ash. a crystaUinc jiin the same u«Uoii, or the of sul\)hocy- led in colour- )le in alcohol, ilk of alcohol, •ties. It con- i out ammoniii h. When dis- cid, and then • very soon, a te of barytes. Ljid, we obtain, acid. If w« it may absorb lite precipitate ash. 1 potash, gives namely, cyan- same time, a istence of the has concluded, lombinations in He thinks that it may be u mixture of mellnnido of potassium, and cyanodidu of potash. SECTION X. — OF NITIlOSULPIIUniC ACID. This acid was discovered by M. Pelouze, in 18.'}5, though the first experiments which led to its discovery were made by Davy, iu 1 791). He observed that dcutoxido of azote is absorbed by a mixture of potash or soda, with an alkidiiio sidphite, and that when the now salt formed, comes in contact with an acid, abundance of protoxide of azote is disenj^nijjed. * M. Pelouzo observed, that if deutoxido of azote be cooled down to 5" or to — 4", anil plaocd iu contact with a solution of sulphite of aainiouia, cooled down to tlie point ut which it begins to con<,a'al, and if wo agitate occasionally, the gas is com- pletely absorbed, and a new salt is formed. This salt uniUsrgoes spontaneous dec-aposition when heated up to ;J2°, or to a hi;4her temperature, beinfj converted into sulphate of amnionia, and prot- oxide of azote. The bulk of the jjrotoxide of azote evolved, being just one-half of that of the deutoxide of azote absorbed. If we umke a concentrated solution of sulphite of aunnonia, and mix it with five or six times its bulk of liipiid aunnonia, a current of deutoxide of azote may be passed through it for hours, without any spontaneous decomposition takin<; place. Fine crystals of the same salt arc {gradually deposited. When these crystals are dried, they may be kept unaltered in a well-stopped bottle.f M. Pclouze has distinguished the acid combined in these crystals with aunnonia, by the name of nitrosulphurir mid. If we place a mixture of 2 volumes of deutoxide of azote, and I volume of sulphurous acid gas, in contact with caustic ]»otash, the whole gas is gradually absorbed. Hut the absorption is not coni- ])lete if any other proportions of the gases be <'mi)loyed. ^Vhen wo examine the salt formed, we find that it contains no sulphurous acid, tor red sidphate of manganese is not discoloured by it. Solution of indigo in sulphuric acid is not discoloured by it, showing the absence cf nitric or nitrous or hyponitrous acids. 'IMie precipitate formed in the salt by any soluble salt of barytes, when well washed with potash, is soluble in nitric acid, showing the ab < see of sulphuric acid. It is obvious from these facts, that nitrosulplmric acid is a com- pound of 2 atoms deutoxide of azote Az'-' O* 1 atom sulphurous acid . S O'"* or of 1 atom sulphur 2 atoms azote 6 atoms oxygen So that its atomic weight is ITS. ' Davy's Researches, p. 238. f Pclouze, Ann. tie Chim. et ae Phys. Ix. Iji. S Az^ 0« = 2 = 3-5 = G 11-5 ! i 784 SOME COMPOUNDS OF AZOTE. I Nitromlphate of ammonia^ is a white salt, having a sharp and slightly-bitter taste, quite different from that of the sulphites. It is neutral, crystallizes in oblique four-sided prisms, generally flat and variously terminated. It is insoluble in alcohol, but dissolves readily in water, and is decomposed into sulphate of ammonia, and protoxide of azote, with so much the greater rapidity the higher the temperature is. Alcohol precipitates this salt from its aqueous solu- tion. When heated up to 230o, it is decomposed with an explosion, protoxide of azote being given out with great rapidity. All the acids disengage protoxide of azote, and cause it to pass into sulphate of ammonia. Even ar. addition of caustic ammonia does not prevent this salt from undergoing spontaneous decomposi- tion, though it renders that decomposition much slower. Spongy platinum, o^ide of silver, metallic silver, charcoal powder, oxide of manganese, &c., decompose it as they do binoxide of hydrogen, protoxide of azote flying off, and sulphate of ammonia remaining. These bodies themselves undergo no alteration. When solutions of chloride of mercury, sulphates of zinc and copper, persulphate of iron, protonitrate of mercury, chloride of chromium, or of nitrate of silver previously cooled by a freezing mixture, were dropt into a solution of nitrosulphate of ammonia, a strong effervescence took place, protoxide of azote being disengaged, and sulphate of ammonia remaining. With acetate of lead there is an effervescence, and sulphate of lead formed. The presence of a quantity of alkaline solution prevents these decompositions. This salt is composed of 1 atom nitrosulphuric acid 1 atom ammonia . 1 atom water 11-5 2-125 1-125 14-750 Nitrosulphate of potash is white, very soluble in water, insoluble in alcohol ; destitute of smell, having a slightly bitter taste and neutral. It crystallizes in irregular six-sided prisms, not unlike those of nitre. At 230°, it undergoes no change and loses no weight. At 266°, it is destroyed, but not in the way that nitrosulphate of ammonia is. Deutoxide of azote is disengaged, and sulphate of potash remains. The acids, even the weakest, disengage deutoxide of azote from it. Spongy platinum, and the other substances men- tioned above, decompose it, protoxide of azote being disengaged, and sulphate of potash remaining. But the decomposition is much slower than with nitrosulphite of ammonia. This salt may be dissolved in boiling water without decomposition. It is anhydrous, and consists of 1 atom nitrosulphuric acid . 11-5 1 atom potash .... 6 17-5 NITROSULPHURIC ACID. 785 sharp and (hites. It lerally flat t dissolves nonla, and higher the ueous solu- i explosion, . it to pass ic ammonia decomposi- •. Spongy ler, oxide of f hydrogen, t remaining. c and copper, chromium, or e, were dropt effervescence i sulphate of effervescence, ity of alkaline Nitrosulphate of soda is much more soluble than the preceding salt, but in other respects resembles it. The attempts made by M. Pelouze to obtain nitrosulphuric acid in a separate state, were unsuccessful. When 2 volumes of deutoxide of azote, and 1 volume of sulphur- ous acid were left in a tube with a little water, sulphuric acid was gradually formed, and i volume of protoxide of azote remained in the gaseous state. !5 !5 ater, insoluble [tier taste and lot unlike those ses no weight. Titrosulphate of id sulphate of Igagc deutoxide pbstances men- Vg disengaged, [o'sition is niucli I decomposition. 'U ll-5 r R-5 3 E lU f n\ i 1 ,i 786 SAP OF PLANTS. il r DIVISION II. OF THE PARTS OF PLANTS. We have in the preceding Division enumerated and described the different ingredients of plants, so far as they have been iiitherto investigated. We now undertake a more difficult task, namely, to explain the composition of each vegetable organ in all the numerous families of plants which constitute the vegetable kingdom. This task, indeed, in the present state of vegetable chemistry, cannot be fulfilled. By far the greater number of plants have never been examined at all ; and even of those which, from their medicinal virtues or nutritive qualities, have attracted the attention of chemists, only particular organs have been analyzed, while the rest have been ne- glected as unworthy of notice. Nothing, therefore, either resembling a complete view, or an exact arrangement, is to be looked for in this Division. I shall satisfy myself with stating the most important facts hitherto discovered respecting the composition of plants, as far as I am acquainted with them, under the seventeen following heads : 1 Sap 2 Peculiar juices 3 Gases 4 Barks 5 Roots 6 Bulbs 7 Wood 8 Pith 9 Herbaceous plants 10 Leaves 11 Flowers 12 Fruits and seeds 13 Ferns 14 Lichens 15 Mushrooms 16 Fuci 17 Diseases. CHAPTER L OF THE SAP OF PLANTS. It is the general opinion of physiologists, that plants receive a con- siderable part of their nourishment by the root ; that it enters into them in a liquid state, and passes up in proper vessels towards the leaves. This liquid is distinguished by the name of sap. In the spring when the buds begin to expand themselves into leaves, if we break off the extremity of a branch, or cut into the wood of a tree, this sap flows out, and may be obtained in considerable quantities. It was first examined by Dr Hales ; but chemical analysis had not made sufficient progress in his time to enable him to ascertain its constituents. Deyeux and Vauquelin have more recently analyzed the sap of different trees. To them we are indebted for most of the anal The Vauf .-.nd ^till andt SAP OF PLANTS. 787 jribed the n hitherto namely, to ! numerous om. This , cannot be never been nnal virtues emists, only ve been ne- p resembling cd for in this st important plants, as far )\ving heads : facts known respecting this liquid. A few additional facts have been ascertained by John. The sap in all the vegetables hitherto examined is nearly as liquid as water. It always contains an acid, sometimes free, but more com- monly combined with lime and potash. Various vegetable principles are also present : of these sugar is the most remarkable, and mucilage. Sometimes albumen and gluten, and sometimes tannin, can bo detected. When left to itself, the sap soon effervesces and becomes sour ; or even vinous, when the proportion of sugar is ( onsiderable. Hitherto the sap of a few species of trees only has been examined. We are not in possession of any means of collecting tho sap of the inferior orders of plants. The expressed juices of a considerable number of vegetables, indeed, have been prepared for medicinal pur- poses ; but these are not sap, but a collection of all the liquid sub- stances which the plant contained. At present, then, it is not possible to present a general view of the properties of sap. The following are the particular species which have been examined : — 1. Sap of the Elm, tilmus campestris. Vauquelin collected three different specimens of the sap of this tree ; the first portion towards the end of April, the second in the beginning of May, and the third about the end of May. It had a reddish-brown colour ; its taste was sweet and mucilaginous ; and it scarcely altered the colour of . ' infusion of litmus. Ammonia, barytes, and lime water throw u a copious yellow-colouved precipitate, which dissolved with otfervescence in acids. Oxalic acid and the nitrate of silver throvv down a white precipitate. Diluted sulphuric acid occasions a brisk effervescence, and disengages the odour of acetic acid. Chlorine destroys the colour of the sap, and throws down a brown precipitate. Alcohol produces a flaky precipitate. When evaporated by a gentle heat, a pellicle forms on the surface; brown flakes precipitate, and an earthy matter is deposited on the sides of the vessel. The earthy matter was a mixture of carbonate of lime and vegetable sub- stance. The liquid, after depositing these bodies, and being eva- porated to xaths of its oi'iginal bulk, contained a considerable por- tion of acetate of potash. 1039 parts of this sap were composed, according to Vauquelin's analysis, of Water and volatile matter . 1027*904 Acetate of potash . . 9*240 Vegetable matter . . 1*060 Carbonate of lime . . 0*796 The vegetable matter was partly extractive and partly mucilaginous.* 0.1 analyzing the same sap somewhat later in the season, M. Vauquelin found the quantity of vegetable matter a little increased, ?.nd that of the carbonate of lime and acetate of potash diminished. Still later in the season the vegetable matter was farther increased, and the other two ingredients farther diminished. The carbonate * Ann. de Chim. xxxi. 20.' II ^MSi 11 mk . vLw& ' iP Wb ■ 'll^ ft-* ■| ir -IH 'Br '' hft HflU J.I r, ijil h;. ^mM % m iMI 788 SAP OF PLANTS. il' of lime was held in solution by carbonic acid, of which there existed a considerable excess in the sap. It is to this acid gas that the air bubbles, which so often accompany the sap as it issues from the tree, IS owmg. 2. Sap of the Beech, fagus sylvatica. Vauquelin collected two different specimens of this sap ; the first in the end of March, the second about the end of April. It had a reddish-brown colour, and a taste similar to the infusion of tan. It slightly reddened vegetable blues. Barytes, ammonia, carbonate of potash, and oxalate of ammonia, occasion precipitates in it ; chlorine throws down yellow flakes ; sulphuric acid blackens it, and disengages the odour of acetic acid ; sulphate of iron strikes a black, and glue throws down a copi- ous whitish precipitate. When gently evaporated to dryness, it leaves a brown extract amounting to about ^y^ of its weight, duct'le while hot, but br-ttle when cold, and having the smell and somewht t of the taste of new baked bread. It absorbs moisture from thi, atmosphere, and increases in weight about f th. Lime disengages ammonia, and sulphuric acid acetic acid, from this extract. Alcohol dissolves only a small part of it. This sap contained the following ingredients : — Water ,! Acetate of lime with excess of acid Acetate of potash Gallic acid Tannin A mucous and extractive matter Acetate of alumina. It contained, besides, a colouring matter, which may be fixed on cotton and linen by means of alum, and dyes them of a fine solid reddish-'^rown colour.f 3. Sap of the Hornbeam^ carpinus sylvestris.X Three specimens of this sap were collected by Vauquelin during the months of March and April. It was limpid, and its colour was whitish ; its taste nllghtly sweet, and its smell analogous to that of whey. Barytes throws down Trom it a copious white precipitate, soluble in muriatic acid. Carbonate of potash likewise throws down a precipitate solu- ble in acids with effervescence. Sulphuric acid deepens the colour, and evolves the odour of vinegar. Oxalic acid throws down a copious precipitate, and nitrate of silver gives the solution a fine red colour. 3918 parts, when distilled, left an extract of a reddish- yellow colour, amounting to 8*279 parts. It had a sharp taste, ana attracted humidity from the air. When tlie e>' tract is digested In alcohol, about the half of It dls- polves. This, portion conoists of extractive, a saccharine matter, and acetate of potash. The residue, which is soluble in water, consists of mucilaginous matter, acetate of lime, and a colouring substance. * See Coulomb, Jour, de PIij's. xlix. 392. f Ann. de Chim. xjl.ii. 2G. X I presume the carpinus betulus is meant. SAP OF PLANTS. 789 I existed t the air the tree, cted two arch, the lour, and vegetable ixalate of wn yellow r of acetic wn a copi •• Iryness, it rht, ducf'e I somewhi *; e from th<; disengages t. Alcohol le following be fixed on a fine solid ee specimen? iths of March Ish ; its taste ey. Barytes )le in muriatic ecipitate solu- ns the colom-, irows down n itionafinercil of a reddish- harp taste, anu . half of it dis- jharine matter, luble in water, [id a colouring Clilm. X5..0. 20. When this sap was left exposed to the air in an open glass vessel, it became milky, disengaged carbonic acid, acquired a spirituous smell and taste, and its acidity increased. After sume weeks this odour was dissipated, and carbonic acid was no longer extricated. Its acidity continued still to increase, white flakes fell to the bottom, and the liquid became transparent. After 50 days the acidity was found diminished, a mucous pellicle formed on the surface, which became at last blackish brown, and the liquid had only a mouldy taste. In a close bottle the sap never became transparent ; and when t^ie bottle was opened after three months, the air which it con- tained was found converted into azote and carbonic acid. The liquid had a very strong taste of vinegar.* 4. Sap of the Birch, hetulus alba. The sap of this tree is colour- less ; it has a sweet taste ; reddens vegetable blues. Neither am- monia, alcohol, nor chlorine, produce any change upon it. Barytes and lime throw down a precipitate which dissolves in muriatic acid. Hydrosulphurets, sulphate of Iron, and glue, produce no effect. Oxalic acid throws down a white precipitate. Sulphuric acid dis- engages th^ odour of vinegar. Nitrate of silver strikes a red colour. When evaporated to about ^th, it lets fall a reddish-brown powder insoluble in water. When 3918 parts of the sap were .ivaporated to dryness, they left 34 parts of brown extract. This had an agreea- ble taste, attracted moisture from the atmosphere, and was almost completely soluble in alcohol. When this extract is dissolved in water, and mixed with yeast, it ferments, and the fermented liquor yields a considerable portion of alcohol ; it yields also a considera- ble portion of vinegar. Vauquelin did not succeed in his attempts to obtain crystallized sugar from this sap ; but he ascertained that it contained a portion of extractive which dyes wool of a brownish- yellow colour. Acetate of lime and of alumina were also present, and probably also acetate of potash .f More lately Dr John has made a few experiments on the sap of ti.e birch. He found it transparent, colourless, destitute of smell, and scarcely sweetish. Its specific gravity was 1*004. One por- tion of birch sap which had been frozen did not alt^v vegetable blues ; but another portion which had no been frozen reddened them. From 1730 grains of sap he obtained only 4 grains of sugar. He fouTii in it likewise a little carbonate of lime, which precipitated of its own accord when the sap was left exposed to the air. He tliought likewise that it contained traces of a tarti'ate, some gummy matter, and some albumen.t 5. Sap of the Yoke Elm. This sap has a bitter taste. When cvtporated to dryness it leaves a brown extract, in which crystals of nitrate of potash are gradually formed. This extract was scarcely soluble in alcohol. It gave traces of the presence of acetate of potash and acetate of lime.§ 6. Sap of the Vine, ntis vinifera. This sap was examined by Dr ♦ Ami. de Chim. xxxi. 31. f Ibid. 36. I Chetniscbe Untersuchungcn, ii, 4. § Ann. de. Chim. xxxi. 38. il i.UrV| ■I :'' a ill il' ^''ll'-ll ry. 790 THE PECULIAR JUICES Prout. It had the whitish appearance of common river water. Its taste was sweetish but not roufjh. It did not alter litmus paper, nor did its specific gravity differ from that of pure water. Potash and ammonia gave it a fine red colour, and threw down red flocks readily dissolved by acetic acid. It was slightly precipitated by oxalate of ammonia, i'errocyanate of potash, nitrate of silver, and subacetate of lead. 2300 parts of it when evaporated left only 1 »art of residuum, half of which was carbonate of lime and the re- ,na«nder a peculiar vegetable matter, which was insoluble in alcohol. The sap had contained both carbonic and acetic acids, and likewise an alkali.* Several specimens of the sap of the vine were examined by M. Robiquet. He found in them carbonic acid, tartrate of lime, bitartrate of potash, and a mucilaginous and flocky matter, the vegeto-aniraal matter of Deyeux.f 7. Sap of the common mapple, acer campestre. The sap of this tree was examined by Professor Scherer, of Vienna. It has a milky aspect, a sweetish taste, and its specific gravity varies. It dr-^s not alter litmus or turmeric paper. It is precipitated by oxalate of potash, nitrate of silver, and barytes water ; but not by muriate of barytes. When boiled it lets fall gluten in flocks. It yields when evaporated a salt with basis of lime possessing peculiar properties. The acid is destroyed by heat, and according to Scherer differs from every other vegetable acid. He therefore distinguishes it by the name of aceric acid. The acerate of lime is white, slightly translucent ; has a weak acidulous taste, and is not altered by exposure to the atmosphere. 1000 parts of cold water dissolve 9 parts, and 1000 parts of boiling water 17 parts of this salt.J Boussingault has lately examined the sap of the musaparadisica. It is limpid like water. When left exposed to the air it lets fail red flocks. It stains linen, but loses this property by exposure to the air. To contains 1 Tannin 2 Gallic acid 3 Acetic acid 4 Common salt 5 Salts of lime, potash, and alumina.§ CHAPTER II. t OF THE PECULIAR JUICES. P I The sap passes from the roots in peculiar vessels to the leaves, where it is altered by a process similar to that of digestion in ani- mals, and formed into all the liquid substances requisite for the * Annals of Philosophy, v. 109. f Jour, de Pharmacie, xviii. 36. X Schweigger's Jour, iv- 362. § Jour, de Pharmacie, xxii. 365. THE PECUMAU JUICES. 791 ver water. Iter litmus )ure water. y down red )recipitated I silver, and left only I and the re- e in alcohol, and likewise ire examined rate of lime, matter, the 3 sap of this a. It has a ;y varies. It scipitated hy , ; but not by in flocks. It ssing peculiar ing to Scherer 3 distinguishes white, slightly edby exposure ^e 9 parts, and usaparadisica. air it lets fall )y exposure to Is to the leaves, Idigestion in ani- [•equisite for the pacie, xviii. 36. nacie, xxii. 365. purposes of the plant. These liquids flow from the leaves towards the root in appropriate vessels, and have received the name of the peculiar juices of vegetables. They differ very considerably from each other in different plants. They have all a certain degree of consistency, and always contain much more vegetable matter than the sap. In the present state of vegetable chemistry, an accurate detail of their properties cannot be attempted. Indeed, it is often difficult to procure them from any plants unmixed with the sap. They sometimes exude spontaneously, and may always be procured in smaller or greater quantify by incisions through the bark of the pi- Ats containing them. The following are the species of peculiar juices which have been hitherto attended to : — 1. Milky Juices. Many plants, when wounded, emit a consiJer- able quantity of a milky liquid, which may, in most cases, be considered as one of the peculiar juices of the vegetable from which it flows. These milky liquids gradually concrete into a solid matter, which has been distinguished by the name of gum resin. Several of these gum resins being employed in medicine, have been descriued among the vegetable principles, which constitute the First Division of this part of the system. This arrangement is, perhaps not, strictly speaking, accurate, as it has not been proved that these gum resins constitute peculiar vegetable principles. But it is convenient, and there is every resin to exp' t, that when these gum resins come to be more thoroughly exau-ned, not a few new vegetable principles will be discovered among them. Indeed, this has been already verified in opium, to which, from peculiar circumstances, the atten- tion of chemists has been particularly turned. For an account of every thing at present kno' respecting the chemical nature of the gum resins, I refer to a px .ceding Chapter in this volume. A few remarks respecting some other milky juices not there alluded to, may be here subjoined. The root of the campanula rotundifolia yields a milky juice, of a peculiar, and not unpleasant smell and taste. Children in some parts of Scotland collect the plant for the sake of this juice, which they suck with avidity. Its chemical properties have not been examined. I imboldt mentions a tree which is a native of South America, which yields a milky juice, employed by the natives as a nourishing article of food. It is called in the country the cow-tree, and the railk of it, on standing, forms a film on the surface, resembling in its propertleL the curd of milk.* This liquid, which exudes from the galactodendron utile, contains a peculiar vegetable principle, which I have distinguished by the name of galaciin, and of which an account has been given in a pre- ceding Chapter of this volume, while treating of the,^a;erf oils. The different species of euphorbia yield milky juices, which, of course, vary in their nature according to the species. In a preced- ing Chapter of this volume, while treating of the gum resins, an * Ann. de Chim. et de Phys. vii. 182. ^^■i 4 ^ iMi ;?■'* ! '■ : f 1 u ,,i I 792 THE PECULIAR JUICES. : •i. ',! 'li I account has been given of euphorhium^ which is the concrete milky juice of the euphorbia officinalis. The milky juice of the euphorbia myrtifolia^ a plant which grows in the West Indies, has been subjected to a chemical analysis by M. Ricord-Madianna,* who obtained Water 73-2 Resin ..... 1*8 Fixed oil containing euphorbin . 4*8 Mucilage 0*3 Extractive . , . . 1*4 Cerin 11*6 Viscin 0*3 Lignin 0*2 Myricin 3*7 97-3 hH i The juice was treated repeatedly with alcohol, which was filtered and left for several days at rest. It deposited cerin. Evaporated, it left a yellow resin, soluble in ether. The remaining liquid was of the consistence of a syrup. Its smell was strong and disagree- able, and its taste burning. Ether dissolved a little resin from it. The residue stained paper like an oil. It would not dry. At first it rendered litmus paper green ; but after being kept a month it reddened that paper. When treated with an alcoholic solution of potash, a kind of black soap was formed, soluble in water. When decomposed by binoxalate of potash, a blackish poisonous matter nrecipitated. This is the substance which M. Ricord-Madianna has called euphorbin. The various species of euphorbia, so abundant in this country, yield a milky juice, which has a hot taste, analogous to that of pepper, but more acrid, and which continues for a long time in the mouth. When chlorine was poured into this juice, a very copious white precipitate fell down. This powder, when washed and dried, had the appearance of fine starch, and was not altered by keeping. It was neither affected by water nor alkalies. Alcohol, assisted by heat, dissolved |ds of it, which were precipitated by water, and had all the properties of resin. The remahiing third part possessed the properties of the woody fibre. Mr Chaptal tried the same experi- ment on the juices of a great number of other plants, and he constantly found that chlorine precipitated from them woody fibre.] Dr John made a set of experiments ou the milky juice of the euphorbia cyparissias. Its colour is milk-white. It is opaque, and has a slippery feel. Its taste is at first sweetish with an impression of bitterness ; and it leaves a feeling of burning heat in the mouth and on the tongue, which continues for some time. He found its constituents as follows : — * Jour, de Pharmacie, xvii'i. 589. f Ann. de Chim. xxi. 285. THE PECULIAR JUICES. 793 ;rete milky rhich grows ilysis by M- •h was filtered Evaporated, ing liquid was and disagree- j resin from it. dry. At first ept a month it ^olic solution of water. When isonous matter cord-Madianna n this country, rous to that oi ong time in the , a very copious xshed and dried, red by keeping, ^hol, assisted by water, and had Art possessed the [he same expen- plants, and he them woody [iky juice of the It is opaque, and Tth an impression tat in the mouth He found its rim. xxi. 285. Water Tartaric acid . Resin Gum Extractive Albumen Caoutchouc Fixed oil 77 13-80 2-75 2-75 1-37 2-00 99-67* The different species of the poppy (papaver) and lettuce (Jacuta) yield a milky juice, which possesses narcotic qualities, and is dis- tinguished by a peculiar taste and smell. An account of the constitution of those juices, so far as they have been examined, has been given in a preceding Chapter of this volume, while treating of the gum resins. The milky juic which exudes from the jairopha elastica^ the hevcea cauotchouc, the artocarpus integrifolia, the urceola elasticOy and from several other plants, gradually becomes inspissated when exposed to the air, and constitutes caoutchouc. All the facts hitherto ascertained respecting this curious milky juice, have been stated in a preceding Chapter of this volume, while treating of the neutral vegetable principles. The juice of the papaw tree possesses properties which dis- tinguish it from most others. According to the analysis of Vauque- lin, its constituents resemble \ ery closely the constituents of blood. Dr John has made some experiments to ascertain the nature of the milky sap of the Asdepias Syriuca, which he was enabled to examine, from the plant being cultivated in the Botanic Garden at Berlin. The sap of this plant is milky, reddens vegetable blues, has a peculiar smell similar to that of narcotic substances. Its taste is sourish, peculiar, but not hot. Its consti'iuents were as follows :— • Resin ..... 26*5 Caoutchouc .... 12*5 Gluten 4 Extractive .... 4 Tartaric acid ") held in solution by Albumen 5 water " . . 73 120*0t The milky juice of the Chondrilla Juncea^ a plant which vegetates abundantly in the neighbourhood of Frankfort, consists, according to the same chemist, of water, holding in solution mucilage, resin, and caoutchouc, in the following proportions : — Mucilage Resin ...... Caoutchouc ..... 1 . 1 t <': \ ! , iif • Si; :,i ii'i p 1^ * Cbemische Untersucbungen, i. 8. f Ibid, i, 20. J Cbemische Untersucbungen, ii. I. 794 THE PECULIAR JUICES. We have aIso, by Dr John, an analysis of the milky juice of the Leontodon laraxicum. He found in it Water Caoutchouc Bitter extractive A sweet tasted substance A trace of resin A trace of gum A free acid Muriate, phosphate, and sulphate of lime Ditto of potasii.* The milky juice of the Laduca saticahos also been examined, and found to contain, 1 A bitter principle, soluble in water and alcohol, insoluble in other, not precipitated b) salts of lead 2 Albumen 3 Caoutchouc 4 Wax 5 An acid 6 Chloride of calcium , . 7 Phosphate of lime ' ' 8 Potash 9 Guru and acetic acidt 10 Nitrate of ammonia.:!: 2. Mucilaginous Juices. The peculiar juices of many plants are not milky, and some not distinguished by any strong taste or smell. In these mucilage seems to be the predominating matter. The substance called cambimn, too, if we may be allowed to con- sider it as a peculiar juice, since it is obviously different from tlu' sap, is entirely mucilaginous. It makes its appearance, according to Mirbel, in all those parts of vegetables where new matter is to be formed, and seems necessary for all such formations, either as the matter employed in their formation, or as furnishing a proper bed for them to be formed in. It does not appear to be confined in vessels like the other juices.§ 3. Some juices are intermediate between volatile oils and resins. These have been distinguished by the names of turpentines and balsams, and have been described in a preceding Chapter of this volume, while treating of liquid resins, 4. Other juices obtained by excision possess at first the properties of resins, or at least acquire them before they are brought into this country. Such, for example, are tacamahac and mastich, and the other resinous bodies described under the name of resins, in a pre- ceding Chapter of this volume. 5. Some peculiar juices arc composed almost entirely of tannin, or at least are characterized by containing a superabundance of * Chcmische Untcrsuchungen, iii. 1. ■f JouT. de Pharmaeie, xxii. 6.53. X Ibid. xxi. 807. § Mirbel, Ann. de Mus. d'Hisc. Nat. No. xl. p. 294. THE I'ECULIAH JUICES. 795 juice of the un cxamincel, i, insoluble in many plants are r taste or smell. Bitter, allowed to con- fferent from tlif ance, according ,ew matter is to ations, either as iishing a proper "■•o be confined in , oils and resins. turpentines awl IChapter of this rst the properties brought into this mastich, and the ' resins, in a pre- itirely of tannin, [perabundance ot that substance. Such, probably, are the juices of onk, sumach, and of most vegetables that yield abundance of the tannin principle. In some cases, it would seem that the juices oxiule spontaneously ; though in general they are obtained by artiticial means. 6. Some vegetables possess juices characterized by the great quantity of sugar which they contain. Such, for example, are the sugar-cane, the carrot, and the various species of beet. For it is surely more reasonable to consider the saccharine matter in these plants as belonging to the peculiar juices, than as confined to the sap. 7. Finally, the peculiar juices of some plants are characterized, by containing a considerable portion of saline matter. Thus the various species of sorel contain a notable quantity of binoxalate of potash, and several of the scdums malate of lime. In short, the peculiar juices of ])lant3 are ne.arly as numerous as the vegetable principles themselves; and when the fungi, algae, lichens, and several other of the numerous inferior tribes of vegetables have been once examined, it cannot be doubted that the number will greatly in- crease. Braconnot examined tiio juices of a number of plants, in order to ascertain the peculiar acids which they contained. The foUow- injr is a short abstract of the results which he oVttained: — * The expressed juice of the aconitnm lycortonum evaporated to dryness, and incinerated, leaves 0*01 of carbonate of potash. This juice contains a considerable proportion of citric acid, partly com- bined with potash and partly with lime. Perhaps also malic and acetic acids are present in the juice of this plant. I'he juice of the delphinum elatum, the rominmlns aconiti/olitts, the thalictrum Jlavum, the clematis recta and vificel/a, likewise con- tains a quantity of citric acid like the preceding juice. The juice of the salvia sclarea contains benzoic acid probably combined with potash. The juice of the ruta graveolens contains malic acid combined with potash and with lime. The juice of the enpatoriuin cannahinum contains an acid which appears to be the malic, mixed w ith some phosphoric. The juice of the nicotiana rustica and tabacum contains malic acid combined with potash and lime. The juice of the mirahilis jalapa contains nitric acid, muriatic acid, malic acid, and a little sulphuric acid chiefly combined with with potash. The spinacia oleracea contains oxalates of lime, and of potash, malate, and phosphate of potash. The tropceolum majus contains phosphoric acid, nitric acid, and malic acid united to lime and to potash. The ricinus communis contains malic acid, doubtless combined with potash. Hii xxi. 807. ). 294. • Ann. de Chim. kv. 277. 79G TUB GASES IN PLANTS. r'A < The Phytolacca flemmlrn contuins an uncommon proportion of potash, and an acid which posseaflcs the properties of the oxalic. The juice of the vaccinium myrtillua or hUberry, contains a colour- ing matter, citric, and malic acids, and a considerable quantity of uncrystallizable sugar. Charcoal removes the colouring matter completely from this juice. When diluted with water, and mixed with yeast, it ferments readily, and yields a considerable quantity of sugar.* 8. The liquid found in the nectariura of different flowers has been called nectar by Buchner. Wo have an examination of the nectar of the agave geminiflora by M. Buchner, junior.f Ho found its specific gravity 1*09. It had a sweet taste and a putrid smell, which it lost by exposure to the air. He obtained from it 1 A volatile principle having a putrid smell 2 A very small quantity of pollen 3 An uncrystallizable sugar, with a trace of sulphate of lime. M. Anthon examined the nectar of the agave lurida.X Its specific gravity was 1*23. Besides sugar, it contained chloride of calcium, and of magnesium, and albumen. CHAPTER in. OF THE CASES IN I'LANTS. J ■[': In many plants the stem is hollow and filled with air. In others, as the onion, the leaves are filled with air. Air is lodged in the pod of the pea, in the leaves of some species of fuci. In short, there is hardly a plant th.at docs not possess some part more or loss hollow, and of course filled with air. Now, it is a question of some curiosity to determine what species of gas thus fills up the hollow parts ot plants. Is it common air ? Or is it a secretion by the plant itself? On the latter supposition it may be hydrogen gas, azotic gas, carbonic acid gas, or any other gas whatever. A few experiments were made by Dr Priestley on the air in tlie sea-weed. He found it sometimes the same as common air ; in other cases it contained a greater proportion of oxygen, in others a greater proportion of azote. The air within the leaves of onions and in the bladder of senna he found the same as common air. Air pressed from the stalks of the common ^tf^f contained a greater pro- portion of azote than common air.§ The air, in two or three plants examined by Dr Darwin was the * Vogel, Annals of Philosophy, xii. 232. f Jour, dc Pharmacie, xxi. 307. % ^^^^' $ Priestley, iii. 279, p. 307. JIAItKS. •97 aportion of oxalic. us a colour- quantity of ring matter and mixed bio quantity ers has been ,f the nectiir le found its )utrid sn\oll, m it ,c of lime. lurida.X Its ;d chloride of flnmo as common air. Hubert found the air from the nrundo bumbos worse tlian common air. M. Hidault do Villiors examined the air in a conMlderablo innnber of plants. That in tho leaves of the onion was the same as eoui- nion air. Tho same observation applies to the air in the petals of the mch prppo In tho capsules of tho cotufm nrftorescen/i, tho pods of the pisum sativum, tho capsules and vesicles of the stnphytea pinnnlrtf ;uid nUjella damascenn, tho steins of the borayo officinalis, conium maculntum, aoncfius okraceus. In sonie cases ho found tho air in tho leaves of onions extinguish a candle ; it must, of course, h vv -'. contained a considerable excess of azote.* From those few observations it seems to follow, that tho air con- tained in plants is common air, frequently imaltcred ; but sometimes deprived of a portion of its oxyffcn. In Dr ' riestley's experiment it would appear that a redundancy of oxygen was presoiit. liut this experiment would require repetition before it could be consi- dered as authenticated. CHAPTER IV. * '; OF BARKS. I lii ir. In others, 3 lodged in the uci. In short, irt more or les3 aestion of some 3 up the hollow ecretion hy the hydrogen gas, tever. ,n the air in tlic omraon air ; i» iygen, in others [leaves of onions (Uimon air. Air id a greater pro- Darwin was the 307. The bark is the outermost part of vegetables. It covers the whole plant from the extremity of the roots to the extremity of the branches. It is usually of a green colour : if a branch of a tree be cut across, the bark is easily distinguished from the rest of the branch by this colour. If we inspect such a horizontal section with attention, we shall perceive that the bark itself is composed of three distinct bodies, which, with a little care, may be separated from each other. The outermost of these bodies is called tli. • idermis, the middle- most is called i\\c parenchyma, and the inut; laost, or that next the wood, is called the cortical layers. The epidermis is a thin transparent membrane, which covers all the outside of the bark. It is pretty tough. When inspected with a microscope, it appears to be composed of a number of slender iibres crossing each other, and forming a kind of net-work. It seems even to consist of different thin retiform membranes, adhering closely together. This, at least, is the case with the epidermis of the birch, which Mr Duhamel separated into six layers. The epi- dermis, when rubbed off is reproduced. In old trees it cracks and decays, and new epidermes are successively formed. This is the reason that the trunks of many old trees have a rough surface. Davy was induced by some observations of Mr Coats of Clifton, * Ann. de Clilai. kxxviii. 89. h > ■i! 19S BARKS. h ' :r to examine the epidermis of the bamboo, the sugar cane, and the equisetum hyemale. He found in them a great quantity of silica. When examined before the microscope, the epidermis of these grami- nivorous plants constitutes a brilliant retiform tissue : which gives it the harsh feel by which it is distinguished. The epidermis of the bamboo was found to contain 17*4 per cent, of silica, and it had the appearance when pulverized of pounded glass. He found also silica in the epidermis of the sugar cane, the common bog reed (arundo phragmites), wheat, barley, and oats. He found a still greater proportion of silica in some other of the graminivorous plants.* The parenchyma lies immediately below the epidermis ; it is of a dc^p-green colour, very tender and succulent. When viewed with a microscope, it seems to be composed of fibres which cross each otiier in every direction, like the fibres which compose a hat. Both in it and the epidermis there are numberless interstices, which have been compared to so many small bladders. The cortical layers form the innermost part of the bark, or that which is next to the wood. They consist of several thin membranes, lying the one above the other ; and their number appears to increase with the age of the plant. l]ach of these layers is composed of longitudinal fibres, which separate and approach each other alter- nately, so as to form a kind of net- work. The meshes of this net- \v'ork correspond in each of the layers ; and they become smaller and smaller in every layer as it approaches the wood. These meshes are filled with a green-coloured cellular substance, which has been compared by anatomists to a number of bladders adhering together, and communica,ting with each other. Fourcroy supposes that the epidermis is the same in its nature in all trees, and that it possesses constantly the properties of cork ; but this opinion is not likely to be verified. The cortical layers seem, at least in many cases, to have a similar fibrous basis ; a basis possessing essentially the properties of flax, which is itself merely the cortical layers of linum usitatissimum. Common cork, which constitutes the epidermis of the querciis suber, is composed of a cellular tissue, whose cavities contain a variety of foreign substances, which may be separated by rasping down the cork and treating it with various re-agents as is done with wood, in order to free the lignin from foreign matter. Ten parts of common cork when treated in this way are reduced to 7. This residue was considered by Chevreul as a peculiar substance, which he distinguished by the name of suberin. The properties of suberin have not yet been accurately determined, owing to the difficulty of obtaining it in a state of purity. Sul- phuric acid readily chars it. Nitric acid gives it a yellow colour, cor- rodes, dissolves, and decompt, >es it ; converting it partly into suberic acid, partly into a substance resembling wax, partly into artificial tannin, and partly into a kind of starchy matter.f * Nidiolsoii's Quarto Journal, May, 1 799. f Bouillon Lagrange, Ann. de Cliira. xxiii. 50. BARKS. 799 , and the of silica. ;se grami- [nch gives ideriuis of and it iiad found also bojr reed ind a still )U3 plants.* is ; it is of len viewed vliich cross pose a liat. tices, which ark, or that membranes, i to increase composed of other altev- i of this net- !ome smaller ood. These tance, which iers adhering' ly determined, [purity. Sul- Iw colour, cor- jy into suheric linto artificial Common cork. "- Washed cork. Suberin. 0-18 0-9 1-0 14-72 17-5' 10-0 16-00 10-G 7-6 14-40 19-G 22-4 45-3 48-G 41-0 Suberin is very inflammable, burning with a lively flame, while at the same time it swells considerably, but does not melt. When distilled it yields water, and a colourless oil ; then a yellow-coloured oil. These liquids are all acid. If the distillation be continued, a brown oil comes over with a little ammonia, and a fatty crystallized substance, which does not dissolve in caustic potash. During the jirocess combustible gases are disengaged, and there remains a por- ous charcoal weighing |th part of the suberin employed. Chevreul treated given weights of common cork, washed cork, and suberin, with nitric acid, and obtained the following products : Fibrous white insoluble matter Resin .... Oxalic acid Suberic acid What is wanting to constitute the hundred parts is a yellow bitter substance held in solution by the mother water, together with car- bonic acid and water, formed at the expense of the constituents of cork. Chevreul obtained from the epidermis of the birch, cherry-tree, and plum, a quantity of suberic acid, which was always the greater the purer the epiderraes employed were. Hence it would appear that these epidermes have a constitution analogous to that of cork. According to John, the young epidermis of the birch differs essen- tially from cork in this respect. It is soluble by boiling in caustic potash ley, and when the brown-coloured solution is treated with an acid, yellow flocks fail, which become brown on drying. This precipitate is slightly soluble in boiling alcohol, but most of it falls again when the solution cools. The matter of the parenchyma, and the juices which exist in barks, vary extremely, and probably occasion most of the differences between them. Some, as oak bark, are characterized by their astringency, and contain tannin ; others, as cinnamon, are aromatic, and contain an essential oil ; others are bitter, as Jesuits' bark ; some ai'e chiefly mucilaginous, others i-esinous, &c. But in the present state of the subject, an enumeration of tlie ditTerent kinds of barks is not to be expected. I shall therefore, satisfy myself with detailing the properties of those barks that have been subjected ta examination. The following are the most remarkable of these : — 1. Cinchona. Peruvian Bark. The tree which yields this cele- brated bark is a native of Peru. It was lirst observed a few miles south of Loxa, a small town on the river Catamayo, nearly in the same meridian with Quito, but in south latitude 4° 1 and at a height of nearly 7000 feet above the level of the sea. The use of this bark in curing intermittent fevers was known to the Americans before the conquest of Peru. But they concealed its virtues from the Spaniards, in consequence of the detestation in which they held 'A' m m ■ m ;■:<: I ' \ n i 800 BARKS. MT ■t ^ ..I them. It was known, however, to the Corregidor of Loxa in 1638. In that year the lady of Count Cinchon, Viceroy of Peru, was afflicted with an obstinate intermittent fever, which her attendants were unable to cure. The Corregidor of Loxa informed of this, sent a quantity of cinchona to the Viceroy, assuring him, that it would speedily remove the disease of the Countess. In consequence of this information, the Corregidor was himself summoned to Lima, in order to regulate the dose, and point out the method of adminis- tering the remedy. Some trials being previously made upon other patients, the Countess took the medicine and was cured. It was this cure that gave the bark celebrity, and made it known in Europe, ■&S a remedy for intermittent fevers. The Countess brought large quantities of it to Lima, where it was known by the name of powder of the Countess, and distributed it to all who were afflicted with in- termittent fevers. Some months after (probably when Count Cinchon returned to Spain in 1639), she consigned her whole stock of bark to the Jesuits, who continued for some time to distribute it gratis. Hence it came to be known under the name of Jesuits' bark. The Jesuits afterwards sent a cargo of it to Cardinal de Lugo at Rome, who distributed it with the same success as the Jesuits had done at Lima, and afterwards consigned it to the Apothecaries' Company at Rome. Hence it came to be known in Italy by the name of Powder of the Cardinal. It was about this time that Louis XIV., while Dauphin, was cured of an intermittent fever by the use of this bark. As he became King in 1643, it is obvious that the cure must have been eflFected before that period. In 1640, when Count Cinchon had returned to Spain, his physi- cian Dr Juan de Vega, who had brought a cargo of it from Peru, sold it publicly in Spain at the rate of 100 reals the pound. The sale continued at this price till most of the Cinchona trees in the neighbourhood of Loxa being exliausted, those whose business it was to collect the bark, began to adulterate it by mixing the barks of many other trees. This speedily brought it into such discredit, that the price sank to 8 reals the pound.* Cinchona, the botanical name of the genus was derived from tlic lady of count Cinchon, who first gave the bark celebrity. The ti m guina or guinagidna applied to the bark is said to have been the Peruvian name given it by the natives of the country. Peruvian bark was at first brought entirely from Peru. But about the year 1760, Mutis, a Spanish botanist, who went to Santa Fc de Bogota, as physician to the Viceroy Don Pedro Misia dc la Cerda, discovered the Cinchona in that country. Since that period a great deal of the bark has been shipped to Europe from Cartlia- gena de Indias. Humboldt informs us that the quantity of cinchona bark annually exported from America, is between 12,000 and 14,000 hundred weight. Sancta Fe furnishes 2000 of these. 1 10 are furnished by * Condaminc. Mem. de TAciid. Royal des Sciences, IT-'jS, p. 226. BARKS. 801 10. in 1638. Peru, was attendants ned of this, lim, that it lonsequence ,ed to Lima, of adminis- ! upon other •ed. It was n in Europe, rought large neoi powder jted with in- when Count r whole stock 3 distribute it Jesuits' bark. \ de Lugo at le Jesuits had Apothecaries' n Italy by the this time that ittent fever by is obvious that )ain, his physi- ■■ it from Peru, pound. The ja trees in the business it was |drl;. i.hat ii\r col- lectors of it in South A^ra rica liavc been often inducou iv adul- terate it, by uilxing witli it the btxi ks of toveral other trees, which happen to bear a certain i'* :cmblaiice tO that of tho true cinchona. Hence it is requisite that the importers anJl purchasers of c'nchona should have the means of examining anJ determiiiing t.e grudness of the bark before they buy it. A very -iimple nieth ,d of making euch an examination was suggested long ago ) : Vauqnelin, and ought to be genorally known.f Tlio chesi^ of bark is in the first ](lace opened, and the pieces carciully coiiipared with each other. It will not be difficult to judge tV . ii their appeai*ance whether they are derived from the same spe- cifcii of tree. Should such differences appear, it will be necessary to examine each kind separately, in order to ascertain which of them, or whether any of them be the tru'^ bark of cinchona. For this purpose, we may proceed in the following way : — Reduce 1 ounce of the bark to a coarse powder, and infuse it in a pound of boiling water. Let the infusion cool, and then filter it through paper, and divide the liquid into four equal portions, put- ting them into four different test glasses. Into the first pour a little of the infusion of nutgalls. If the bark be genuine, there will fall an abundant white or greyish-white precipitate. This precipi- tate indicates the presence of quinina or cinchonina. If the infusion of the bark is not precipitated by infusion of nutgalls, we may at once pronounce that it is not the bark of a cinchona. Into the second test glass let fall a solution of ;7er5M//>/iateo/*iVoH. The infusion will assume a green colour. Sometimes a copious greenish-black precipitate falls, and the supernatant liquid, when it becomes clear, has a green colour. This is owing to a variety of innnin^ which the cinchona contains. The more abundant the pre- cipitate, and the more intense the green colour, the better in gene- ral is the quality of bark under examination. Into the third test glass let fall a little solution of isinglass in water. A white or gi'eyish-white coagulum falls. This is owing to the tannin which all good cinchona contains. Into the fourth test glass drop a solution of tartar emetic. If the bark be of a good quality, a greyish-yellow precipitate will fall. This precipitate is also occasioned by the tannin which good cin- chona bark contains. 2. China nova is the bark of a tree still little known, but distinguish- ed by the names of China nova and ChiJia rcgia, which has been * Jour, de rharmacie, xxi. 513. f Ann. do Cliim. lix. 113. ' |i .!■ BARKS. 803 d docs not e, it is now me of these «0i/ . of the wtVi linown ^ -t-.tM cdby hat ^.- coL- cPii iu adul- trees, which ■ue cirxhona. s of cinchona t;.e goodness r,d of maVmg aiu;ne^i«» and md the ][)iece3 aficult to judge the same spe- je necessary to ivhich of them, ona. For this and infuse it in [Tid then filter it I portions, put- he first pour a mine, there will This precipi- If the infusion lalls, \se may at 'sulphate of iron. itimes a copious t liquid, when it ir to a variety ol bundanttheprc- e better in gene- a of isinglass in This is owing ar emetic. >cipitate w Tftk ill fall. which good cin- n,butdistingmsli- which has been analyzed by Pellctier and Caventou.* They obtained from it a. fatty matter; a red resinous-looking substance, consisting chiefly in extractive from altered tannin. This substance dissolves less easily in potash and concentrated acetic acid, than the red matter from cinchona bark. When dissolved in boiling water it is precipitated by a solution of gelatin, but not by tartar emetic. This bark con- tains also tannin, which is precipitated by solution of gelatine, but not by tartar emetic, and which, when mixed with persulphate of iron, gives a brown precipitate. The bark contains also a yellow colouring matter, gnm, starch, lignin, kinovic acid, and a vegetable alkali extracted by Gruner, but not examined. He informs us that 100 parts of it saturate 12*3 of sulphuric acid. This would make its atomic weight 40*63. Or supposing the salt to be a disulphatc the atomic weight of the alkali would be 20*31 ; which is sensibly the same with that of quinina. Probably, therefore, the alkali \\\ China nova is quinina ; or, perhaps Gruner's alkali may be the sub- stance found more lately in this bark by M. Winkler, and called by him Chinova bitter,^ The kinovic acid of Pelletier and Caventou has considerable analogy with the oily acids, particularly with stearic acid, but it may be obtained without saponification, which is a necessary preli- minary for the oily acids. It may be obtained by treating the al- coholic extract of the bark with alcohol and magnesia. The mag- nesia forms an insoluble compound with the colouring matter, the tannin, and the extractive : while the kinovate of magnesia is dis- solved by the alcohol. If we filter the solution, and add an acid, the kinovic acid is thrown down in white flocks. When this acid is dried, it constitutes a brilliant white light matter. It is very little soluble in water, but dissolves readily in alcohol and ether. Water throws it down from its alcoholic solution in flocks. With the bases it forms salts, which are very easily decomposed by the other acids. The alkaline kinovates are very soluble. The kinovates of barytes and lime are rather more soluble in water than kinovic acid, and dissolve readily in alcohol and ether. Kinovate of magnesia is soluble in water, alcohol, and ether. The solution of it does not precipitate the neutral salts of silver, lead, copper, and protoxide of iron. But it slightly aftects acetate of lead and corrosive subli- mate. It precipitates the salts of cinchonina. 3. Bark of Daphne Mezerium. This bark was examined in 1822 by MM. C. G. Gmelin and Baer.l It has been long known, that when applied to the skin, it has the property of raising a blis- ter. Gmelin and Baer obtained from it wax, an acrid resin, a peculiar crystallizable body, to which they gave the name of daphnin, and which has been already described in a preceding Chapter of this volume ; a yellow colouring matter, an uncrystallizable sugar, gum, * Jour, de Pharmacie, vii. 109. f Ann. der Pharm. xvH. 161. I Schweigger's Journal, fiir Chemie und Fbysik, xxxv. 1. l-'i !l fl , I I ; '■■ w. I, ^< 806 BARKS. I i reddish-brown extractive, free mivlic acid, inalates of potash, lime, and magnesia, probably mahitos of iron and alumina, phosphate of liine, traces of pliosphate of potash, lignin, and silica. If we boil the bark of mczcreon in alcohol, and filter, while hot, the decoction, on cooling, deposits wax. When wo distil the alco- holic decoction, no volatile matter passes over with the alcohol, but there remains an extract which water decomposes into an insoluble resin, and a clear yellow solution. It is to this resin that the bark is indebted for its vesicating property. It lias a green colour ; so deep, that it appears to the eye black. It is hard, and breaks with a conchoidal fracture. Its taste is extremely acrid. Some time ela])ses before it is perceived; but it remains very long in th(» mouth. When isolated, it is only slightly soluble in water, but is much more soluble when mixed with the other principles of the bark. It dissolves in alcohol, and the solution has a deep-green colour. The solution in ether is light green. When distilled per fie, it gives out no ammonia. When boiled with nmriatic acid, it crives out a verv disagreeable narcotic smell. A small portion of the rosni is de- composed and dissolved, but the greatest ])art remnins unaltered. Nitric acid converts it into oxalic acid, and a light-yellow resinous- looking substance. This last substance, by prolonging the action of the acid, is converted into the bitter substance of Welter, and into artificial tannin. This resinous body is, in fact, a compour 1 of a fat, acrid, vesi- cating oil, and another substance. If we dissolve it ir. alcohol, and mix the liquid with an alcoholic solution of acetate of lead, a green precipitate falls. If we now filter the liquid, and thro v down the excess of lead by sulphuretted hydrogen, filter and evaporate the liquid, the oil separates in viscid drops, having a golden-yellow colour. The oil thus obtained has an acrid taste, and vesicates the skin. It is easily converted into so; j;, and without giving out any disagreeable odour. But if we distil the soap, after havinif mixed it with tartaric acid, a strong smell of phosphuretted hydro- gen is perceived, and a liquid passes over into the receiver, whose smell and taste has considerable analogy to that of weak cinnamon water. This liquid contains a small quantity of acetic acid. There remains in the retort, together with tartrate of potash, oily acids, quite free from all acridity. This oil or resinous-like body contains phosphorus ; for when we burn either of them with nitre, we find phosphoric acid in the residue after the combustion. Thus the acrid oil from the bark of Daphne Mezerion contains an ad- ditional constituent; namely, phosphorus; just as the vesicating volatile oils contain sulphur. The portion precipitated by acetate of lead gives, if we mix it with alcohol, and free it from oxide of lead by sulphuretted hydro- gen, a solution which, after being filtered, is brown, and which, when evaporated, leaves a brown residue. Absolute alcohol se- parates the colouring matter, and leaves a white unctuous substance, which was not examined. The alcoholic solution is acid, and has lil BARKd. 807 otasli, limc,^ (hosphate of p, while hot, it'll the alco- alcohol, but an insoluble hat the bark n colour ; so 1 breaks with Some time ' long in thii r, but is much tlie bark. It 1 colour. The ,e, it gives out ves out a very e resin is de- ans unaltorctl. ellow resinous- rurs the action jf Welter, and fyt, acrid, vesi- iT. alcohol, and )f lead, a green thro V down the evaporate the golden-^ellov e, and vesicates hout giving out p, after having huretted hydro- receiver, whose weak cinnamon of acetic acid. e of potash, oily sinous-like body them with nitre, nbustion. Thus , contains an ad- s the vesicating ves, if we mix ii phuretted hydro- own, and which, olute alcohol se- ctuous substance, is acid, and has a disagreeable smell, which becomes alliacious, and most disgusting when an alkali is added to the liquid. Let us now return to the aqueous solution from which the resiu- ous-looking matter had separated. If we distil it in a retort, wo obtain a liquid having a disagreeable smell, and a slightly acrid taste. This liquid is rendered slightly nmddy by acetate and sub- acetate of lead ; but has no action on vegetable blues. The con- centrated liquid is precipitated sulphur-yellow by subacetato of lead. When we filter the liquid, and free it by sulphuretted hydrogen from the oxide of lead which it contains, it leaves, when evajjorate J, an extract, from which absolute alcohol dissolves daphn'm, leaving a peculiar brown-coloured extractive matter. The sulphur-yellow precipitate, thrown down by subacetate of lead, gives, when decomposed by sulphuretted hydrogen, two substances, one of which dissolves while the other remains mixed with the sul- pliuret of lead. When the solution, containing the first of these, is evaporated, it leaves a sweet-tasted uncrystallizable extractive mat- ter, capable of undergoing the vinous fermentation, and, therefore, a species of sugar. When treated with nitric acid, it gives a groat deal of oxalic acid. The second substance may bo separated from the sulphuret of lead by boiling water, which dissolves it, but lets it fall, on cooling, in yellow flocks. It has an astringent taste, is soluble in alcohol, and precipitated yellow by acetate of lead, and reddish-grey by persulphate of iron. It has some resemblance to a compound of tannin and starch.- If Mezerion bark, after having been exhausted by alcohol bo digested in cold water, we obtain a brownish-yellow gum, which when treated with oxalic acid, yields mucic and oxalic acids. The solution of this gum is abundantly precipitated by the infusion of nutgalls ; though the precipitate does not take place immediately. It is also precipitated by acetate and subacetate of lead. Wlien distilled it gives off* ammonia. Boilinjj water extracts from the bark a greater quantity of this gum than cold water does. Such is an abstract of the curious experiments of Gmelin and Baer, on the bark of Mezerion. Gmelin ascertained that the daphne alpina contains daphnin as well as the daphne mezerion. 4. Bark of the root of the ailanthus glandulosa or Japan varnish. This bark was examined by M. Payen,* in 1824. By the suc- cessive action of water, alcohol, ether, &c., he separated the follow- ing constituents : — Lignin, water, starch, gum, vegetable jelly, a.bitter substance soluble in water and alcohol, aromatic resin, chlorophylley an aromatic substance soluble in water, alcohol, and ether and having a distinct smell of vanilla, a fatty matter, a substance con- taining azote, soluble in water and insoluble in alcohol, a substance similar to fimgin, but without azote, a yellow colouring matter, traces of a volatile oil having a strong and acrid smell, traces of citric acid, silica, and some salts. * Ann. de Chim. et de Phys. xxvi. 329. ! I I ; :'| ID '■ fci I I \]r 1;! ! i' w :i 1 w 808 BARKS. ?i; :iti " ' , The aromatic substance more soluble in alcohol than in water or other, is remarkable for the striking,' similarity between its smell uiul that of" vanilla. It is not easy to IVee it completely from the other constituents of tlie bark. The aromatic resin gives out an agreeable smell, when it is thrown on a hot iron and evaporates in a white smoke. The vegetable Jelly is insoluble in water and alcohol ; but forms with ammonia a compound soluble in water. When this compound is dried, it has the form of transparent white plates, which are brit- tle and not altered by exposure to the air. It is neutral and gives out ammonia when treated with the requisite reagents. When this compound is dissolved in water, the jelly may be separated unaltered, by saturating the ammonia with sulphuric acid. A slight excess of the acid renders the jelly a little soluble in water ; but the addi- tion oi carbonate of lime restores its insolubility. It is easily re-dissolved by ammonia. The substance analogous to fungin possesses all the characters of that substance, but is destitute of azote, which Braconnot shewed to be a constituent of the fungin from mushrooms. b. Bark of the croton eleutheria. This bark constitutes the eleu- theria and cascarilla of the shops. It is usually in rolled pieces, and has some resemblance to reruvian bark. It has an aromatic smell, and an agreeable bitter taste. Whca burnt it emits an aromatic odour resembling that of musk, i^r the only chemical analysis of this bark hiMierto published we are indebted to Pro- fessor Trommsdorf; 4696 pans of it yielded him the following products : — * Mucilage and bitter principle . 864 parts Resin 688 Volatile oil .... 72 Water 48 Woody fibres .... 3024 4696 6. Bark of the white willow (salix alba). — The bark of this tree which is common enough in Scotland, is remarkable for its astrin- gent taste, and has been often used in intermittents by the common people. It has lately been proposed by Bouillon La Grange as an excellent substitute for Peruvian bark ; being composed, according to him, of the very same constituents, to which that bark owes its medicinal virtui . A very superficial examination, however, may satisfy any one, that the properties of the two are very far from siuiilar. The decoction of this bark has a dark-reddish colour ; and ac- cording to Bouillon La Granj^ , when repeated decoctions are made with the same portion of bark, the last is always deepest coloured. It is precipitated abundantly by glue, carbonate of potash, and car- Ann, de Cbim. xxii. 219. n.vuKs. 809 in water or ts smell iiml 111 tlio other when it is ; but forms ia compound iiich are brit- ral and gives , When ibis ;ed unaltered, sligbt excess but tbo addi- It is easily 5 cbaracters of onnot sbcwed cutes tbe eleu- rolled pieces, IS an aromatic nt it emits an 5 only cbemical iebted to Pro- , tbe loUowiug 64 parts 88 72 48 1)24 1)96 ark of tbis tree c for its astrin- 3y tbe common Grange as an »osed, according bark owes its bowever, may B>e very far from colour ; and ac- octions are made leepest coloured, potasb, Itonate of ammonia. Lime-water throws down a precipitate, at firdt blue, and afterwards bufi'-coloured. Siilj)hate of iron tiirows down n very dark-green precipitate. Alcoliol separatesj white flakes. When evaporated to dryness, a reddish brittle subislancc remains, which has a very bitter taste, and does not attract moisture from the atmosphere. When alcohol is digested over this bark, it acciuires a greenish- yellow colour. The tincture ia rendered muddy .y water. When evaporated it leaves a brilliant yellow substance of a very bitter taste which melta at a moderate heat, and emits an aromatic odour.* These experiments indicate the presence of tannin, bitter princi- ple, extractive, and gluten, in this bark. 7. Bark of the pinus sylvestris. This bark having been recom- mended by M. Westring as a fe'trifuge, lierzelius was induced to subject it to analysis.f He obtained the following constituents : — sugar Soft resin Tannin with apotheme Extractive with principle Kinate of lime Vegetable jelly Moisture and loss and bitter Insoluble matter 6-92 6-65 15-00 0-53 18-15 5-25 52-50 47-5 100 The soft resin is strictly speaking, a combination of resin and volatile oil. It has an agreeable savour of the fir, which it gradu- ally loses as it becomes hard. It has a greenish-brown colour, and its alcoholic solution is greenish-yellow. The vegetable jelly possesses all the characters of poetic acid. The woody fibres of the young bark possess all the cbaracters of the amylaceous fibrin of potatoes. Tl"7 swell out in water, and are converted into a gelatinous mass, which, whe.:, dried, assumes the aspect of horn. It would appear, from this, that ' iio pectic acid is mixed in fir bark with starch. To this mixture tl.e bark proba- bly owes its nutritive properties, being occasioualiy employed in times of scarcity in Scandinavia as a substitute for bread. 8. Bark of the cesculus hippocastanum or horse- chesnut. The bark of this tree, which forms so fine an ornament in parks and avenues, has lately been proposed in Paris as a remedy in intermittents, and a set of observations on it have been published by Mr Henry.:}: Water or moderately strong spirits are the best solvents of it. Strong alcohol dissolves but little. The watery infusion has a fawu colour and a bitter taste, without astringcncy. It is preciti- • Ann. de Chim. liv. 290. t Afhandlingar, iii. 347, and Traite de Chiniie, vi. 228. X Ann. de Chim. Izvii. 205. . I ■ ill ill .H^ 810 BARKa. J I ,v • tatcd abumlantly l>y irclatine, ami sparingly by acids. It precipi- tates iron <,''r('(;n. V\ ith nitrate of mercury it lorius a copiimn pre- cipitate. The int'usion of nut;,''all.'4 and tartar ometic proihu-e n(t eh'ect upon it. from tliese proi)ertie!i it ia obvious tliat it (lillei.-, entirely ia its constiriients from the ditlbront spociea of cinchona; examined l)y VaiKpieliu. M. Cauzoneri, however, has announced that il contains an alkaloid very similar to ([uinina or cinchonina. (rice Jour de Vliai- vmcie, ix. 542.) He baa ju^ivc i it the name of iescuUn. !). liar/t of (/ueniifi rohor, or oak. This bark, so Ion;; and uni- versally cmiiloyed for t iniin^^ leather, has been but iniperfectl\ examined. Davy found lon^'' ai.ro, that 100 parts of it contain 12*7 parts of cxtractiv(% and (i\J of tannin. Uraconnot found tlint ii contained a considerable (piiintity of pectin.* When oak bark, nftor haviiij; been cxbanated by tainunn', is put into water, a kind of i'er- mentation takes ])lace, and an acid licpiid Ik formed, which its em- ployed in one of the j)reliiniu!iry processes of tanninjf. Uraconnor has shown that the acid thus formed is the lactic; and the licpiid, called y«A't'e, by French, contains acetate of lime, tannin, aijotiienic, a jiumniy matter, free acetic acid, and a groat quantity of lactat'' of lime, together with lactates of magnesia, potash, ammonia, au i probably of nuvngancse and iron.f 10. liar/i of Popxilim trvinvhi. The bark of this tree luis drawn the attention of chemists, in consequence of Braconnot's discover\ of two febrifuge })rinciples in it, to which the names of salicin ami pojmlin have been given. These substances have been already de- scribed in a preceding ( 'hapter of this volume. The infusion of this bark, when treated with persulphate of iron, tartar emetic, gelatine, and infusion of nutgalls, exhibits exactly tlu> same characters as the infusion of cinchona bark. Besides salicin .and populin, it contains a species of tannin, apparently the same with that in cinchona bark, and which furnishes the same rod coloured apotheme. This tannin has the characteristic property of assuming a light-green colour when supersaturated with caustic magnesia, and exposed to the air. This phenomenon does not ap- pear when lime is substituted for magnesia. Nor has it been per- ceived in any other kind of tannin. To the apotheme from the tannin of the trembling poplar, Bra- connot has given the name of corticin, because it is generally met with in barks. Besides the substances already mentioned, Bracon- not found in tbis bark gum, a peculiar substance, soluble in watei and alcohol, and which, when mixed with salts of gold, silver, or mercury, reduces the oxides to the metallic state ; tartrates of potash and of lime, pectic acid and lignin. 11. lietula alba. The epidermis of the birch tree ia composed of a numbf^' of hiyers, easily separable from each other, and very coni- bustibk'. It was examined by Gauthier, who extracted from it * Ann. de Chira. et de Pliys. 1. 881. t Ibid. p. 376. It \)rccii)i- ^iroiUu-e no ,t it dillor.H f c'uK'liuiui; jontaius* an ur de Phat- iijr and uui- impi'i'lcctl} [•o»\tau» l"^'T jinul tliiit it k biirU, HtU'T I kiml of ler- wbic-'U isi 0111- limconnot tul the iiiiuiii, ill, aiiothoiiu', fity of lactat'' immonia, an I rcc has ilrawn lot's (Uscovei\\ of saliciii. and en already do- Iphatc of iron, )its exactly tlio iesides saliciu ..tly the same the same roil tic property ot with caustii' )U does not a\)- as it been per- i llxtrai'tivo • • 11-2/5 Suboriii . • • a.'i-oo Gallic acid und tuunin 5*5 Alumina • • 2-0 Oxide of iron , 4-6 Silica • • 3-75 Carbonate of lime . 2-5 •11 99'()0» 12. linrhofthe Wintcrnnia cnnvlla, Tliis bark was examined in IHIJ), by M. Henry .f It contains an acrid vo/atile oil, an aromatic resin, colonral extractivv, an extractive mattir soIuIjIo in boilins^ water, f/itin, starch, vegetable albumen, acetates, oxalates, and c/«/o- rides of lime and potash, and litjuin. In 1822, I'etro/ and llobi- nett examined the same bark, and found, in place of the coloured extractive, and the extractive soluble in boiling water, a peculiar species of sugar, and a very l)itter-tasted extractive. Hut the rest of their analysis agrees with tiiat of Ilonry. The sugar cryatal- lizes, and seems to he a variety of maiinite. 13. Hark of anf/uslura vera. M. Saladin has ascertained, that when the infusion of the ani/usttira vera is treated cold, with absolute alcohol, antl the liipiid is left to spontaneous evaporation, crystals arc deposited, to which he has given the name of cusparin. The crys- tals arc tetrahedrons. Cusparin is neutral. It melts at a low temperature, losing 23*09 per cent, of its weight. Cold water dissolves half a per cent., and boiling water I per cent, of it. It dissolves in the concentrated acids, and in the alkalies. It is precipitated by the infusion of nutgalls.§ 14. Bark of Imxus sempervirens, or box tree. This bark was sub- jected to a chemical examination by M. Faure, who found it to con- tain 1 Chlorophylle ... 0*6 2 Buff-coloured matter . . 0*3 3 Wax 1-4 4 Azotized tallow , . . 1*1 5 Resin ..... 4*0 Extractive . . . . 14*1 7 Malate of buxina . . . I'l 8 Gum 4*4 9 Lijrnin .... 67*8 10 Ashes 5-2 100*0 The ashes consisted of sulphates of potash and lime, carbonates of liine and magnesia, phosphate of lime, oxide of iron, silica. || Buxina has been described in a preceding part of this volume. *!': :• f: al Jour, de Pharm. xiii. 545. f Ibid, ^ Ibid. xxii. G62. V. 480. X Ibid. viii. 197. II Ibid. xvi. 428. 812 ROOTS. 15. Quillaia saponaria. When the bark of this tree, which is a native of Chili, is pulverized, and mixed with water, it froths like soap, and is generally employed as a substitute for soap, by the in- habitants of the country. A small portion of the bark oi this tree was put into the hands of MM. Henry, jun., and Boutron-Charlard for analysis, by M. L'Eveille. But the result of the analysis was imperfect, in consequence of the small quantity of bark at the dis- posal of these chemists. They obtained 1. A peculiar sharp-tasted substance, soluble in water and alco- hol, frothing when agitated with water, and drying iu thin trans- parent crusts. 2. A fatty matter, combined with chlorophylle. 3. Sugar. 4. A brown colouring matter, rendered deeper by the alkalies. 5. Gum, a trace. 6. A free acid. 7. Malate of lime. 8. Starch. 9. Chloride of potassium, and phosphate of lime. 1 0. Oxide of iron. 11. Lignin.* CHAPTER V. OF ROOTS. J The roots of a great variety of plants are employed in medicine and the arts. The substances found in them are various ; and in- deed, as the peculiar juices of the roots are always included in sucli examinations, it is clear that almost all the vegetable principles will be found in them. I shall notice in this Chapter the principal roots employed in medicine and the arts. 1. Beta vulgaris. There are two varieties of the beet^ one, the roots of which are red, while those of the other are white. The root is large and pulpy, somewhat like that of the carrot ; but much larger. It has been long cultivated as a nourishing food for cattle. The root of the beet is sweet, owing to the presence of sugar in it. M. Pelouze has shown that it contains no raannite nor uncrystal- lizable sugar, but only a sugar exactly the same as that obtained from the sugar cane.f When the root of white beet is grated down to a fine pulp, and the juice expressed, and the residue thoroughly washed and dried over the water-bath, 100 parts of the root only leave 2*5 parts of the residue. But the manufacturers of beet-root sugar only express 7C per cent, of juice, and leave 30 per cent, of residue. This must be owing to the imperfection of the method employed by them, for * Jour, de Pharmacic, xiv. 252. f Ann. de Chim. et de Pbys. xlvii. 411. ROOTS. 813 reducing beet-root to a pulp. For when M. Pelouze grated down the pulp, by means of a hand rasp, he never obtained more than 12 per cent, of residue.* M. Pelouze determined the quantity of sugar in a given weight of beet-root, by mixing its juice with yeast, and converting it into alcohol by fermentation. The specific gravity of the alcoholic li- quid obtained, gave him the quantity of alcohol formed from a given weight of beet-root. He had previously ascertained, that 100 parts of sugar furnished exactly 51 parts of anhydrous alcohol. The following table exhibits the results obtained with 27 varieties of beet : Sugar per cent. White beet from Bonduef ... 5*8 Do. . . . . . . ' . 6*2 Do. (well manured) , . , 6*3 Do 7-2 Do 7-2 Do 7*5 Do. (well manured) ... 8 Do 8-0 Do. (well manured) . . . 8'3 Do 8'5 Do. (well manured) . . . 9*0 Do 9-2 Red Beet (well manured) . . . . 9*8 Do 9-8 White beet, from FamarsiJ: . . . 7'2 Red, from do. ...... 6*6 White, with red skin, from do. . . . 9"2 Red, from do. . . > . . . 9*8 White, from do. 8*5 Yellow, from do. . ... 9 Red beet, from Famars . . . . 9 Beet of two years after seeding ... Red beet of 1 year 7'5 White do., from Dunkirk .... 8*2 Do. with red skin, from do. • . . 9*5 White do., from Arras . • . . 9*5 Do. with red skin, from do. . . .10 Be^Sroot has been examined by M. Payen§ and M. Dubrunfaut, as well as by M. Pelouze. Besides sugar, they found albwnen, a sub- stance containifig azote, lignin, pectic acid, malate of potash^ oxalate of potash, ammonia, and lime. 2. Anthemis Pyrethnim, or fellitory of Spain. The root of this plant, formerly much used as a gargle, and still employed as a sia- lagogue, was analysed by M. Koene, in 1 835.|| It had been previously subjected to a chemical examination by MM. Gautier^ and Parisel.** * Jour, de Pharmacic, xvJ. 418. f Bonduo is a village 2 leagues from Lille. X Near Valenciennes. § Jour, Chiin. Med. i. .385. II Ann. de Chim. et de Phys, lix. 327. f Jour, de Pbarnj. six, 2a I. ** Ibid, iv, 49. !i; (=^'5 iii li m t f m ',' 1 |, ■ i ;| I ' 1. ii ^ ' wm - ilJM IS HBTil^' ;: 814 nooTS. i i The root is long, fusiform, about the thickness of the finger, rough, fawn-coloured externally, white within, fibrous, and almost destitute of smell. Its taste is acrid and shghtly acid, and leaves a very lasting impression in the mouth. There is some difference in the results of the different chemists, in their accounts of the constituents of this root. M. Gautier obtained Volatile oil, a trace — Yellow colouring matter 14 Gum .... 11 Inulin 33 Chloride of calcium, trace — Lignin 35 98* He considers the property of the root of pyrcthr um to excite a flow of saliva to reside in the fixed oil, which has a b [•own colour, and it. lighter than water. M. Parisel obtained Acrid matter (pyrethrin) . 3 Inulin .... 25 Gum .... 11 Tannin 0-55 Colouring matter 12 Liirnin .... 45 Chloride of potassium 0-79 Sili-ca .... 0-85 Iron .... trace 98-19 With a trace of volatile oil. M. Koene, whoso analysis was published in 1835, obtained 0-95 1-60 0-35 A brown acrid resin, insoluble in caustic potash An acrid brown fixed oil, soluble in caustic potash A yellow acrid oil, soluble in potash Tannin, a trace . . . Gum ........ 9-40 Inulin 57'70 Sulphate, muriate, and carbonate of potash, phos- ") phate and carbonate of Ume, alumina, silica, ?• 7*60 oxides of iron and manganese . . j Lignin 19'80 97-40t The active principle of the root from this analysis consists of three different 3ubstances. It is soluble in sulphuric and acetic ether, and in alcohol. Water partly separates it from the alcoholic solution, but the liquid remains muddy. It is quite insoluble in water. Muriatic and nitric acid have no sensible action on it. * Jour, de Phar^;.lcio, iv. 50. f Ann, de Chim. et de Phys. lix. 328, and Jour, de Pliannacie, xxii. 88. he finger, nd almost .d leaves a hemists, in iv obtained ■xcite a How )lour, and i-- tained 0-95 1-60 0*35 9-40 57-70 \ 7-GO 19-80 97-40t sis consists of ic and acetic the alcoholic e insoluble in action on it. cie, xxii. 88. HOOTS. 815 Concentrated sulphuric acid dissolves it, and destroys the acrid principle. If we add water to the solution, flocks precipitate, and a foetid odour is developed. Caustic potash partly dissolves the acrid principle, leavings un- dissolved a brown acrid matter. The solution mixes in all propor- tions with water, and the acids separate the oil unaltered. The insoluble brown mattei- has an insupportably acrid taste. It is insoluble in weak alcohol. Stronjr alcohol dissolves it, and the solution becomes milky when mixed with water ; so that it possesses the characters of a resin. To the acrid substance M. Parisel has ofiven the name of pyrethrin. But it appears from these results of M. Koene, that it is not a simple vegetable principle as he sup- posed, but a compound of two oils and a resin. Probably the difference in the proportion of the constituents in the analyses of Gautier and Koene, was owing, at least in part, to differences in the roots examined. 3. Daucus carota. The root of this plant, the common carrot, is too well known to require any description. It bas been subjected to an analysis by M. Vauquelin* and by M. Wackenroder.f Vau- quelin showed that the expressed juice of the carrot contains com- mon sugar, incrystallizable sugar and mannite, but none of this last substance could be discovered till the common sugar had been sub- jected to fermentation, and converted into alcohol. He found in it also a fatty resinous matter, and albumen, malic acid, and a peculiar principle held in solution by the sugar. The residue of the carrot, freed from its juice, when treated with potash, yield.s, as Braconnot had already shown, abundance of poetic acid. Wben peciic acid is heated in a crucible, with an excess of potash, (taking care not to raise the heat too high) it is converted into oxalic acid. Wackenroder informs us that the carrot juice has a brick-red colour, and is muddy. Its smell is similar o that of carrots, its taste sweet, but harsh. It coagulates at a temperature under 212°. The coagulum is yellow, and when dried amounts to 0*629 of the juice. It is composed of 0'435 of vegetable albumen, and 0*10 of a tatty oil, 0*034 of carotin, and 0*06 <,f earthy phosphates. When this juice is distilled, it gives out j-^i^j-^ of its weight of volatile oil. This oil is colourless, has a strong carroty smell, a strong taste, re- maining long in the mouth, and a specific gravity of 0-S8()3, at the teui})orature of 54°. It is little soluble in water, but very soluble in alcohol and ether. The substance to which Wackenroder has given the name of carotin, may be extracted by ether, either from coagulated carrot juice, or from carrots <;ut into thin slices and dried. The ether contains the carotin, mixed with a fatty colourless oil. If we eva- porate away the ether, and treat the residue .with caustic ammonia, the oil will be saponified and dissolved, while the carotin remains hehind. Redissolve it in ether, add a little alcohol to the solution, • Ann. de Chim. et de Phys. xli. 46. f Cominenlatio de Anthelm. de Rega. Veg. Gott. I ,'■ J in, ly 1S26. 816 HOOTS, II ti >4 I ! and leave it to spontaneous evaporation. The carotin crystallizes in small ruby-red needles, mixed with globules of the oil. Put the crystals on bibulous paper to absorb the oil, and wash the carotin with a little ammonia. The crystals are very small oblique four-sided tables. Carotin has neither taste nor smell, and has no action on vegetable colours. Heat softens, but does not melt it. It is not volatile, but burns when heated, without leaving any residue. It is slightly soluble in anhydrous alcohol. Ether does not dissolve it, unless when it is mixed with fat oil. It is soluble in fixed and volatile oils, butter, and other analogous substances. The solutions are yellow, and are speedily rendered colourless by exposing them to the solar rays. This is the reason why carrots do not yield carotin, except when they are fresh. 4. Bryonia alba, white bryony. The root of this plant, which is so abundant in the middle districts of Europe, was formerly a good deal employed in medicine. The fresh root, when taken into the stomach, acts violently as an emetic and purgative, and was at one time thought to produce temporary madness. This root is large, long, fleshy, compact, externally yellowish-grey, internally white. It is marked by transverse streaks. Its taste is nauseous, very acrid, bitter, and slightly astringent when fresh ; but it loses these characters when dried. It was analyzed by Vauquelin in 1807,* afterwards by MM. Brandes anu Firnhaber,t and by Duleng d'Astafort.J It has a certain analogy with the root of beta vulgaris, but con- tains much less sugar, and is distinguished by a peculiar bitter- tasted substai \ discovered by Vauquelin, which has been dis- tinguished by che name of bryonite. According to Brandes and Firnhaber, the root of bryonia alba is composed of Bryonite, with a little sugar , 1*9 Resin, with a little wax . . 2*1 Soft resin . . - , 1*3 Mucoso saccharine matter . 10*0 Gum 14'9 Starch 2-0 Pectic acid . . . . 2*5 Fibrous starch . . . TO Coagulated albumen , . 6'2 Mucilage . . . : 0*27 Extractive . . . . 1*7 Phosphates of magnesia and alumina 0*5 Malate of magnesia . . . 1*0 Fibrin 15-25 Water ..... 20-0 80-62 * Ann. dc Mus. d'Hist. Nut. viii. S8. f Br. Arch. iii. 351. X Jour, de Phurniacie, xii. 158, 325, 507. ROOTS. 817 •ystalUzes Put the le carotin Carotin le colours, but burns soluble in wben it is >ils, butter, )w, and are solar rays, ixcept -when nt, which is lerly a good iten into the I was at one :oot is large, irnally white, luseous, very it loses these rds by MM. ariSy but con- culiar bittev- has been dis- Brandes awl 9 5 2 27 ■7 5 ^0 1-25 •0 •62 lArch. i". 351- The properties of the bitter substance called hn/onite, and the mode of obtaining it, have been detailed in a preceding Chapter of this volume. 5. Cyclamen Europeum, or sow-wort. The root of this plant, \\hicli is a native of Britain, was formerly employpd in medicine, under the name of radix arthanita;. This root is fleshy, very tliick, approaching to round, and at least as large as the fist. It is black exteriorly, but white within. It has no smell, but an acrid bitter and disagreeable taste. It was at one time employed as a laxative. Saladin found in the root of this plant a peculiar crys- talline substance, to which he gave the name of arthanitite. We have given an account of this substance in a preceding Chapter of this volume. 6. Berheris vulgaris, or barberry. The bark and the fruit of this plant were formerly used in medicine. The root was ana- lyzed by Brandes,* and more lately by Buchner and Herberger.f Brandes found the constituents of this root as follows : — Brown colouring matter, thrown down by " acetate of lead Yellow colouring matter, not thrown down by acetate of lead Gum, with a trace of calcareous salt u Mi 2-55 6-62 Starch, with a little phosphate of 1 Calcareous phosphates Fat oil Chlorophylle Soft resin . Lignin . . Water me. &c. 0-35 0-20 0'20 0-40 0-025 0-55 55-40 3-50 Buchner and lowing constituents Wax Herberger extracted from the same root the fol- Tallow . Resin Berberitc , Gum Starch, traces of Malates and phosphates Lignin Ashes Water and oil . 0-4 0-6 20-4 17-6 21-4 3-4 31-2 2-6 2-0 99-6 i3erberite is an extractive substance containing azote, having a yellow colour and a bitter taste. Its characters and the manner of obtaining it have been given in a previous Chapter of this volume. • Br. Arch. xi. 29. t Jour, do Pharinacie, xvii. 39, and xxi. 309. 3rx ! %m 81B ROOTS. bv -L 7. JRheum palmalum, auatrale^ undulaium, &c. Bhuharh. The roots of various species of rheum constitute the well-known and valuable medicine called rhubarb. Our rhubarb is quite different from the JRheum or rhabarbarvm, which Dioscorides informs us was black, and came from beyond the Bosphorus. Our rhubarb* was imported from China and Tartary, by the way of Russia. When it began to be used as a medicine, 1 do not know, but it was ob- viously in common use in the time of Paracelsus, who died in 1541, being mentioned by him as a common purgative.t But it was not till the year 1732, that naturalists became acquainted with any plant which seemed to yield the rhubarb of the shops. At that time, Jussieu in Paris, and Rand at Chelsea, received from Russia some plants, which were said to be those that yielded it. From these, LinnjBus drew up his descriptv n oi rheum rhabarbarvm, which appeared in the first edition of his Species Fkmtarum. Dr. Hope, Professor of Botany in Edinburgh, raised the true rhubarb plant from seeds sent him by Dr. Mounsey from Petev>;!jurg, and drew up a botanical description of it, under the name of rheum pahnaium, which was published in the Philosophical Transactions for 1 765. Three varieties of rhubarb arc known in commerce, liussian, Turkey, and East India, or Chi7iese rhubarb. The two first grow- on the declivities of a chain of mountains stretching from the Chinese town Sini, to the Lake Koko Nar, near Thibet. It is also cultivated in China. Good rhubarb is in flat, irregular, angular pieces, full of large holes. Its colour is a pure yellow, marbled with red and white veins. It has a peculiar smell, and a bitter, slightly astringent taste. It feels gritty between the teeth ; and when chtwed tinges the saliva of a bright yellow colour. It breaks with a rough hackly fracture, is easily reduced to a powder, which has abright buff-yellow colour. It should not be porous, but rather compact and heavy. Schrader analyzed Russian rhubarb, and the root of rheum palmatum with great care, and obtained from it the following con- stituents : — Resin Bitter principle Oxalate of lime Lignin Gum Russian. R. Palmatum. . 4-8 2-8 r rhubarb 26-4 24-0 • 4-5 9-0 • 49-5 47-0 • 12-8 14-8 97-6 98-0 J3rande found in the root of rheum palmatum, H] :n * Mr David Don has shown, that the plant which yields the East Indian or China riiubarb, is the rheum uustrale. f Paraceisi Opera Omnia, ii. 27. Archidoxorura, lib. 7. Geneva folio editioi) irb. The ;nown and ;e different rms us was ibarb* was ia. When it was ob- ho died in e.t But it lainted with ps. At that from Russia d it. From arum, whicii Dr. Hope, rb plant from id drew up a w pabmttm, for 1765. :ce, liussian, ;wo first grow itip from the rhibet. It is s, full of large ed and white astringent btwed tinges rough hackly ht buff-yellow and heavy, oot of rheum "oUowing con- ilnialum. 2-8 K4-0 9-0 17-0 14-8 97-6 tlie East Inriianoi }eneva folio edUioa ROOTS. Resin 10 Bitter principle of rhubarb 26 Gum .... 31 Lignin .... 16-3 Malate of lime . . . . 6-5 Phosphate of lime 2-0 Water .... 8-2 819 100-0 Hornemann analyzed three varieties, and obtained Bitter principle Yellow colouring matter . Extract containing tannin Apotheme of tannin Vegetable mucilage . Substance obtained bypotO ash from the woody iibre 5 Oxalic acid Fibrin .... Moisture Rhaponticina . Stai'ch .... Russian. Knglish. 1 nhnponticum. 16-042 24-375 i 10156 9-583 9-166 2-187 14-687 16-458 10-416 1-458 1-249 I 0-833 10-000 8-333 3-542 28-333 30-416 40-209 1-042 13-583 0-8'?'? : 15-416 8-542 3-333 3-125 6-043 1 1-04S 14-583 98-061 109-371 117-554* yzed specim ens of the i roots of rheum M. Ossian Henry has ana australe, which had been cultivated near Paris, and obtained Rhein Fixed oil, a trace Bitter principle of rhubarb, or caphopurite Apotheme of tannin .... Extract, with tannin and gallic acid") Gum, with binoxalate of lime 5 Sugar, a trace Starch ....... Oxalate of lime ..... Phosphate and sulphate of lime, oxide of iron Pectin and pectic acid .... Fibrin ....... 7-3 14-0 5-0 1-6 2-0 3-3 0-5 46-0 20-3 lOO-Of 8. Imperntoria ostruthium, now considered by modern botanists: as a species oipastinaca, and distinguished by the name oi paslinaca ostruthium, was at one time cultivated in this ^ountry as a pot-herb. * These tables are copied from Berzelius, Traite de Chimie, vi. 205. The numbers are obviously inaccurate ; but I cannot rectify them, as i have no copy of Hornemann's original paper, from which thej' were taken by Berzelius. t Jour, de Pharmacie, xxii. 40"J. M\ 8-JO KOOTS. Tho root of it was examined by M. Osanii, who dlscovcrod in it a peculiar principle, which Wackenroder, who examined it particularly, distinguished it by the name of imperatvin. Tliis principle may bo obtained by the following process : — Digest the root in ether till every thing soluble in that liquid u taken up. Distil oft* the greatest part of the ether, and leave the residue to evaporate spontaneously. The iniperatrin crystallizes, and a fat oil remains, which is to be decanted off. Subject the crystals to pressure between folds of blotting i)aj)cr, and then dis- solve them in boiling alcohol. When the solution cools, or is allowed to evaporate, the imperatrin crystallizes in oblique four- eided prisms, which are colourless, transparent, and have a vitreous as^pect. Taste peppery, and extremely acrid and burning. When pure it has no smell, but it often retains a little volatile oil, from which it may be freed by fusion. It melts when heated to 107°. When exposed to a higher temperature than this, it gives out an acrid smell, and burns without leaving any residue. When distilled it undergoes decomposition, but gives out no ammonia. It is insoluble in water. 100 parts of alcohol of the specific gravity 0*848 dissolves at t!ie temperature of 59°, 7*11 parts of imperatrin. The solution, which is neutral, is precipitated by water. Ether, oil of turpentine, and olive oil, dissolve it with facility. Caustic ammonia dissolves very little of it ; but caustic potash dissolves it abundantly. Tho acids throw it down from this solution unaltered. Sulphuric acid dissolves imperatrin, assuming, at the same time, a brownish-red colour. Water throws down tho i:nj)eratrin without colour from this solution, (concentrated nitrii acid dissolves the imperatrin without the assistance of heat, givin^^ it a yellow colo;ir. By dilution the imperatrin is thrown down, of a beautiful oranj^e colour. Iodine combines with imperatrin, form- ing a compound of a brownish-red colour, from which tho iodine may be almost completely driven oft" by heat.* 9. Polygala senega. The root of this plant the senega of phar- macy, which is a native of Virginia, and distinguished by the name of ralllesnahe root ^\as employed by the native Americans as a cnrc for the bite of the rattlesnake. This circumstance was made known to the medical world in 1735, by Dr John Tennant,t who had tried its virtues, and found them to hold good. Symptoms of pleuritic affections generally following the bite of the rattlesnake, Dr I'eii- nant was naturally led to try the exhibition of the root in these diseases, and he assures us tnat it was of considerable value. In 1739 it was tried by Du Ilamel, who found it a powerful expcctor- ant.J In 1744, it was exhibited by M. Bouvard in dropsy, and according to his testimony, it is a very powerful hydrogogue.§ The root is woody, branched, contorted, about the thickness of • Berzelius, Traito de Cliiinie, vl. lOiJ. f See his Physical Disqnisitinng, p. 2. I Mem. Tuiis, 1739, p. hib. $ Ibid. 1711 p. 37. ■red in it a ivticularly, pie may be at Viqviid U d leave tlie [•A-ystalli/es, Subject the [id then dis- Kools, or is bliquc four- vc a vitreous ing. When tile oil, from ted to 107°. o-ives out an /lien distilled ' the specific 7-11 parts of ecipitated by isolve it with ; ; but caustic [own from this rin, assuming, rows down the ijntrated nitric ,f heat, giving rown down, of r)cratrin, form- ich the iodine rnrya of phar- d by the name [cans as a cure as made known who had tried )in3 of plem-itK' uake, Di- 'i'^'"' root in these iblc value, hi I verful expcctor- in dropsy, and rogogue.§ he thickness ot !, p. 37. ROOTS. 821 tlic finger, and covered with ash-coloured bark. It lias no smell. Its taste is at first sweetish and nauseous, but when chewed for les8 than a minute it becomes pungent, producing a peculiar and dis- agreeable sensation in the fauces. This root was analyzed in 1804 by Gehlen,* who obtained the following constituents : — Soft resin .... 7'5 Senegin .... 6'15 Extractive, sweet and acrid . 26*85 Gum with albumen , . 9*50 Lignin 46'00 96-00 The characteristic properties of the root are ascribed to the seneffin, which may be obtained by the following process : — Reduce the root to small fragments, and digest it in alcohol till every thing soluble in that liquid is taken up. Distil off the alcohol from this solution till only ith of the liquul remains in the retort. During the distillation an oleaginous matter rises to the surface of the liquid. Evaporate this residue to dryness, reduce what remains to powder and digest it in ether till every thing soluble is taken up. When we distil off this ether a soft resin remains. This resin is brownish-red, unctuous, very fusible, has a smell similar to that of the root, a bitter and slightly acrid taste. Alcohol, ether, oil of turpentine, and olive oil dissolve it with facility. The alcoholic solution reddens litmus paper. Nitric acid scarcely attacks it. Caustic soda dissolves it assuming a reddish-brown colour. The portion insoluble in ether is treated with water, which dis- solves an extractive matter at once sweetish and acrid. What remains is senegin. It ought to be well washed with water. It is a greyish-'vhitc, swollen matter, something like mucilage of starch. When dried it is translucent, brown, hard, and brittle. Its taste is acrid and irritating, similar to that of the root itself. Weak alcohol dissolves more senegin than strong alcohol. The solution reddens litmus paper. Boiling anhydrous alcohol saturated with sonogin deposits it in part on cooling. Senegin is insoluble in ether, and in fat and volatile oils. Though pure senegin be in- soluble in M'ater, it becomes soluble in that liquid when it is mixed with the other constituents of the root. Senegin, when boated, does not melt, but swells up, gives out. fumes, and burns with the smell of burning tartar, leaving a porous charcoal. (!)auslic soda dissolves it into a brown transparent liquid. Nitric acid dissolves it when assisted by heat, and when the solution is concentrated to a certain point, it assumes the form of a jelly. Senega was afterwards analyzed by Feneulle, Dulong,t and Folchi|. But the latest and most elaborate analysis was made by M. Quevenne in 1836.§ He obtained • Berlin Jalirbuch, 1804, p. 112. t Jour, (le Pharmacie, xiii. 567. % ll^i^' P- 617. $ Ibid. xiii. 44^. ^1'. } '1 if-, J<5; •A f'PI \ i J I tm »N , I 1 1* H22 IIOOT8. 1 Polygalic arid, tho senegin of Gehlon 2 Virg'meic ucid 3 Poetic acid 4 Tannin 5 Yellow bitter colouring m.-Aler 6 (iuiii 7 Albunica 8 Cerin 9 Fixed oil. The characters of po/i/fjnlic acid have been given in a preceding part of this volume. The virgineic acid was obtained only in the fixed oil which exi'^lo in the senega root in conaideralde quantity It has a reddisli-brown colo\ir, a svrujjy consistence, a bitter ranci(( very disagreeable taste, and a smell similar to its taste. It reddens litmus paper. When boiled with water and liltercd, tho acpieoua liquid has a sweet taste, which becouies gradually soni-jwhat bitter and nauseous. Persulphate of iron gives it a red colour, but occa- sions no precipitate. Diacetato of lead gives a copious yellow pre- cipitate. Nitrates of silver and barytcs occasion no change, Acetate of copper gives a greyish-nrccr' scanty precipitate. Potash commnnicates a reddish-tint. Another portion of this oil was treated hot with a sohition of caustic potash. It was easily converted into a soap. After a few minutes boiling, the soap reatlily dissolved in water. It was de- r.i/si jiosed by tartaric acid, the tartrate of potash was separated. h "• as distilled, a liquid having a disagreeable smell was obtained, on /hich floated a few drops of oil. The aqueous liquid reddened li! Aius, precipitated diacetate of lead white, but had no action on suits of silver and copper. From these, and some other properties, Quevenne considers this oil as consisting chiefly of a peculiar fatty acid, to wliich he pro- poses to give the name of virgineic acid. But the results obtained are not quite satisfactory. 10. Hdleborus hyemalis. The root of this plant is tuberous, has a yellowish-white colour, and is covered with a black skin. At first it has no taste : but in a short time a strong acridity becomes sensible in the mjuth and throat. Vauquelin has subjected it to a chemical examination, chiefly in order to ascertain the nature of the bitter and acrid principle which it contains. This principle he found to be an oil of a peculiar nature, possessing properties inter- mediate between the fixed and volatile oils. He obtained it by digesting the root in alcohol, and then distilling off the alcohol in an alembic. The oil gradually separated and concreted on cooling. Its taste was extremely acrid, and it had a yellowish-brown colour. When dissolved in weak alcohol, it precipitates the sulphates of iron of a fine purplish-rod colour, which becomes green by means of alkalies. This oil is extremely poisonous, and, according to Vau- quelin, exists in many plants, and is the cause of their poisonous qualities. HOOTS. 823 I a precetVm;? ;(l only in the iil)le (quantity I bitter rancid J. It reddens [, tlio aqueous Muewliat bitter [our, but occa- )U8 yellow pre- ,11 uo cliangc. litate. Potash 1 a solution of . After a few- It was de- was separated. Ill was obtained, iquid reddened id no action on sr. le considers this » which he pro- results obtained is tuberous, ha5 lilack skin. At icridity becomes jubjected it to a the nature of the his principle he properties inter- ; obtained it by ,ff the alcohol m ireted on cooling, ish-brown colour, sulphates of iron een by means ot :cording to Vau- f their poisonous When the root is digested in water, and the li(|uid passed through a cloth, it is obtained opaque and milky, and gridiially deposits a white powder which possessfs the properties of starch. The li(|uid, by evaporation, deposits a biowuish matter, which forms sueeesrfivo pellicles on the surface. This substance possesses the properties of extractive. Heaides these substances, Vauquelin detected a sub- stance analogous to gluten, some sugar, and a poll ion of woody (ibre.* 11. Ipccacnnn. This is tlic root of a plant which grows sponta- neously in Brazil, and probably in other parts of South America. It was lirst correctly described and liururod by Dr Hrotero, under tlu! name of callicocca ipecacuanha .^ Mut more recently the g(nni» catlicocca has been united to th ' '>aetts: The root is about the thickness of a quill, unequal . . ' "id varies considerably in its colour. Wiien pounded it Idest and safest emetic .1 the whole Materia Medica. prol)ably emi)loyed in America from time immemorial, it was not, introduced into Eiu'oj)© till the time of Lewis XIV., when one Grenier, a French mercluuif, brought 150 lbs. of it from Spain; with which trials wore made at the Hotel Dieu. Helvetius lirst made known its use in dysiin- tcry, for which he was rewarded by Lewis XIV. with L. 1 000 sterling.l: This substance has been analyzed by MM. Majendie and Pelletier. The following are the constituents which they obtained ; — Oil 2 Emetina 16 Wax 6 Gum . . . . . . 10 Starch 42 Wood 20 Loss ...... 4 100§ 12. Asclepias vincetoxicum. This plant, the q/nanchum vince- toxicum of Mr Brown, is a native of the south of Germany. Its roots are employed in medicine in some parts of the continent, though they do not enter into the Materia Medica of Great Britain. They consist of contorted febrillje, issuing from a common head. They are long, slender, and have a pale yellow colour, a strong smell which mostly disappears when the) are dried, and a bitter acrid disagreeable taste. As these roots, like epicacuanha, excite vomiting, M. Feneulle was induced to subject them to a chemical analysis, to ascertain whether they contained emetina.\ He obtained the following substances : — 1 An emetic matter different from emetina ; asclepin, 2 Resin 3 Mucilage 4 Starch * Ann. do Mus. Nat. No. xliii. 82. + Linnsean Trans, vi. 137. X Neumann's Chem. p. 357. § Ann. de Ghim. et de Phys. iv. 180. II Jour, de Pharmacie, zi. 806. M ^ ' M H ■ IS V] vQ ^ / ^'^ > <^. .-1^ '} 7 IMAGE EVALUATION TEST TARGET (MT-3) 1.0 K£ 1^ I.I ■yuu III 1.8 Hiotographic Sciences Corporation /!> „*' 4t %^. % Z ^ 1.25 ||U J4 .< 6" ► ■o^ ^> \ 4^ \\ ''.^k <* ^.^«^ o^ 33 WEST MAIN STREET WEBSTER, N.Y. 14580 (716) 872-4503 U 824 ROOTS. 5 A fixed oil, almost of the consistence of wax 6 Volatile oil 7 Pectic acid 8 Ligniq 9 Malate9 of potash and lime 10 Silica, oxalate of lime, with sulphate, phosphate and car- bonate o^ lime. The asclepin was obtained in the following manner : — A decoc- tion of the roots was mixed with acetate of lead, which threw down the malic acid and malate of lime. The filtered liquid was then freed from lead by sulphuretted hydrogen gas, and evaporated to the consistence of an extract. Alcohol being digested on this ex- tract, left a quantity of gT'mmy matter, and dissolved a resin together with the asclepin. The alcoholic solution was evaporated and the residue treated with water. The asclepin was dissolved and the resin left behind. The asclepin was freed from all traces of resin by repeated solutions in water. Thus purified it has a pale yellow colour, attracts moisture from the air, and is very soluble in water, alcohol, and ether containing alcohol. It contuns no azote, and does not exhibit any alkaline Iiroperties. Its aqueous solution does not precipitate acetate of ead ; but corrosive sublimate, infusion of nutgalls and diacetate of lead occasion a precipitate. Infusion of nutgalls does not throw it down immediately. Nitric acid converts it into oxalic acid. Sul- phuric acid chars it. When given to the extent of 3 grains it oper- ates as an emetic. 13. Jalap. This very active cathartic is the root of the plant formerly called c(mvolvulus jalappa ; but which Dr Redmond Coxe, of Philadelphia, has shown to be a species of Ipomcea. He calls it Ipomaa jcUappa. It is a native of Mexico, and is said to have taken its name from Xalapa, a province of New Spain, where pro- bably it was first employed in medicine. But the best Jalap comes from Vera Cruz, in South America. According to Bauhin, it was first brought to Europe in 1609, or 1610. In the shops we find the root both cut into slices and entire. It has an olive shape, is solid, ponderous, blackish on the outside, but grey within, and marked wit]} several dark veins. It has scarcely any smell. Its taste is not strong, but to the tongue and throat it manifests a slight degree of pungency. It was analyzed by Mr Henry, who found its constituents resin, extractive, starch, and lignin.* According to him, the proportions of these different substances, contained in 500 parts of the three varieties of jalap which occur in commerce, are the following : — Reiin. Extract SUrch. .. h'wnin. Jalap leger . 60 75 95 270 sain , 48 140 102 210 pique . 72 125 103 200 Ann. de Chim. lizii. 275. ROOTS. 825 and car- ■A decoc- rew down was tlien lorated to n this ex- d a resin jvaporated I dissolved all traces isture from containing ny alkaline acetate of iiacetate of lot throw it acid. Sul- iins it oper- f the plant ond Coxe, He calls it id to have where pro- alap comes uhin, it was entire. It loutside, hut las scarcely i,nd throat it i,uents resin, proportions J»f the three lowing : — ro 110 )0 It was analyzed in 1817, with much care hy M. Cadet de urt, who made it the subject of his thesis.* He obtained Water . 4-8 Resin 100 Gummy extract • 440 Starch . 2-5 Albumen . , 2-5 Lignin . . , 29-0 Phosphate of lime . 0-8 Chloride of potassiui n . . 1-6 Chloride of calcium 0*04 Carbonate of potash Carbonate of lime 0-38 0-40 Carbonate of iron 0-21 Silica • . 0-54 Gassi- 97-77 With traces of sulphate of lime, carbonate of magnesia, acetic acid, sugar, and colouring matter. According to Gerber,t the jalap of commerce contains Hard resin > < 7-a Soft resin . • . 3-2 Extractive 17-9 Gumm^ extractive 14-5 Colouring matter^ 8-2 Liquid sugar . 1-9 Gum with salts 15-6 Mucilage . 3-2 Albumen . ► '■.■: 3-9 Starch . 6-0 Lignin . 8-2 Malic acid 2-4 Chloride of potassium 0-5 Phosphate of magnesia 1-3 Phosphate of lime . 0-4 Carbonate of lime . 30 Water . • 4-8 102-8 It is believed that the active principle of jalap resides in the resin. As to the jalappin mentioned in a preceding Chapter-of this volume, it has been too imperfectly examined to determine its action. 14. Gentian. This is the root of the gentiana luteal a plant which grows spontaneously in the mountainous parts of France, Switzerland, Hungary, &c. It is said to have been named after * Jour. de'Phannacie, iii. 498. f Br. Arch. Ixiii. 193. X It assumes a fine red colour when acted on by the alkaline carbonates. 826 ROOTS. Gentius, a king of lUyria, who is supposed to have first discovered its virtues. The root is externally brown ; internally yellow, with a spongy pith in the middle. Its .taste is intensely bitter. Gentian was analyzed in 1821, by MM. Henry and Caventou. They found in it 1 A very volatile odorous substance 2 Gentianite .. 3 Bird-lime or viscin •.-» 4 A greenish tallowy substance ' 5 Incrystallizable sugar / -6 Gum 7 Brown extractive - ' 8 Lignin. They could detect no starch nor inulin, the process which they fol- lowed was nearly as follows. , They macerated the root for 48 hours in ether. The liquid assumed a yellow colour. It was decanted off and the greatest por- tion separated by distillation. When the residue cooled, a yellow crystalline mass was deposited, which adhered strongly to every thing with which it came in contact. The remaining ether from which this deposit had fallen was left to spontaneous evaporation, and the mass remaining was macerated in alcohol, of 0*83 specific gravity, as long as that liquid acquired any colour. The alcohol dissolved the gentianin, the odorous matter and the green fat, and left a semifluid colourless substance which was the viscin. It had neither smell nor taste, was insoluble in water, cold alcohol, acids, and dilute alkaline solutions. It was slightly soluble in boiling alcohol, and precipitated again when the liquid cooled. Ether dis- solved it in every proportion. When distilled it passed over un- altered into the receiver. Gentian has been more lately exami. >y M. Leconte, who has shown that the gentianin of Henry and - -«rentou is an acid, which has been already described under the name of gentisin, and that the bitter principle resides in a different substance not yet isolated. The distilled water of gen!larx deserves to be examined. When properly prepared it has a strong smell, a nauseous taste, and pro- duces intoxicating effects. It is obvious, that the bitter principle of gentian is to be found in the aqueous solution of the root.* 15. Valerian. This is the root of the Valeriana officinalis, a plant which grows abundantly in Great Britain. It was* used by the ancients, and is described by Dioscorides under the name of Oou, and no doubt the Phu of Pliny was the same plant. The roots of valerian are long and slender fibres issuing from the heads. It was first brought into estimation in convulsive affections by Fabius Columna, about the year 1592. He informs us that he cured himself of epilepsy, by means of the root of valerian. In this country it is a good deal used as an antispasmodic, and is rather a favourite remedy with many practitioners* * Jour, dc Pharmacie, xuii. 46S. nooTS. 827 discovered jUow, with Caventou. ich they fol- The liquid greatest por- led, a yellow ,gly to every y ether from evaporation, 0-8o specific The alcohol rreen fat, and iscin. It had alcohol, acids, >le in hoiling I. Ether dis- issed over un- an 3onte, who has acid, which and that the yet isolated, nined. When aste, and pro- )itter principle le root.* cinalis, a plant • used by the name of ^o") IS issuing from the ive aft'ections by -ms us that he lerian. In this and is rather a The roots of this plant should be dug up in autumn, when the leaves decay, and be preserved in a dry place. They have a strong peculiar unpleasant odour, and a warm bitter subacrid taste. It is well known that they are peculiai'ly grateful to cats. Trommsdorf subjected this root to analysis. It loses f ths of its weight by drying. Distilled, with water it yields a volatile oil, very liquid, and of a greenish-white colour. Its odour is strong and camphoric; its specific gravity, at the temperature of 77°, is 0'9340; its taste is aromatic and camphoric without being acrid. When ex- posed to the light it becomes yellowish. Nitric acid converts it into a resinous substance, or, if it be used in a sufficient dose, into oxalic acid. The expressed juice of the roots of this plant is muddy, and has a strong odour. It lets fall a portion of starch. It con- tains a peculiar substance approaching the nature of extractive, soluble in water, but insoluble in ether, and in pure alcohol. It is precipitated from water by the salts of lead, silver, mercury, and antimony. This juice contains also a portion of gum. The roots deprived of this juice yield a portion of black-coloured resin, but consist chiefly of lignin.* 16. Horse-radish. EinhofF has examined the root of this vege- table, the cochlearea armorica, and found that its acridity is owing to the presence of a small quantity of volatile oil, which he obtained by distilling the mashed roots in a water bath. A liquid came over, which was at first milky, but gradually deposited a little of the volatile oil in question. This oil had a pale yellow colour, and the consistence of the oil of canella. Its odour was that of horse-radish, excessively strong. Its taste was at first sweetish ; but it left an acrid impression, and excited inflammation in those parts of the tongue and lips to which it was applied. It is heavier than water, with which it forms a milky liquid by agitation. It dissolves readily in alcohol. It is volatilized at the temperature of 60°. The liquid obtained from the roots of the horse-radiah, hy distillation, yielded traces of sulphur .t 17. Elecampane. The roots of the inula helenium or elecampcme were examined by Rose, who extracted from them the peculiar vegetable principle called inulin. M. Funke afterwards subjected them to a new analysis, and obtained the following substances : — A crystallizable volatile oil Inulin Extractive Acetic acid - - [ A crystallizable resin Gluten A fibrous matter (lignin ?).% John subjected the same root to analysis, § and obtained Ann. de Chim. Ixx. 95. t Ibi«]. 185. $ Chemische Untersuchungen, iii. 61 :{: Ibid. luvi. 98. 1! i i; i» 828 ROOTS. Helenin . ' . 36-66 Mucilage 4.44 Extractive* . 36-66 Soft resin 1-66 Wax . . . 0-55 Camphor 0-41 Lignin . 5-55 Insoluble extractive 13-88 dr. V. 13*33 1 1 10 4 4 6 36-67 Phosphate ofpotash, chloride of do. 1 ' sulphate ofdo., with potash united > 2-08 ' to vegetable acids • • 3 Phosphates of lime and magnesia, 1 • lime united to vegetable acids, >■ 3-33 ' trace of phosphate of iron, silica 3 v^ 105-22 V. 18. Sweet flag. The roots of the Mwua calamuSt or sweet flags, have been subjected to analysis by Trommsdorf. According to him, 64 ounces of this root are composed of the following ingre- dients : — Volatile oil • • • • Inulin 1 ' ' Extractive, with some muriate of potash 2 ' Gum, with some phosphate of potash 3 A viscid resin .... 1 Woody fibre ... 13 Water 42 64 Of 19. Andropogon schcmanthus. The root of this plant, from the isle of France, was examined by M. Vauquelin. It was found to contain, 1. A resin similar to that of myrrh. 2. A bitter colouring matter, soluble in water. 3. An acid. 4. Oxalate of lime. 5. Abundance of oxide of iron. 6. Much woody fibre.| 20. Aristohchia^ serpentariot or snake-root birth-wort. The root of this plant has been used in medicine, at least since the year 1632, and probably earlier. It is a native of Virginia. The root is perennial, and composed of a number of small fibres, proceeding from * It had a bitter and acrid taste, and probably contained sugar, f Ann. de Chim. Ixxxi. 332. % Ibid. Ixxii. 302. M. Henry analyzed the root of the Andropogon muriatus, and found its constituents similar to those of the A. Schananthus. See Jour, de Pharmacie, xiv. 57. § The name, ariatolochia, occurs in Dioscorides, who informs us that there are three species, which he describes (lib. iii. cap. 4.\ But as the aerpentaria is a native^ of America, it is obvious that neither of his species can refer to it. The name is derived from the supposed virtue of the plant in cleansing the lochia after child-bearing. Hence the English name birth-wort, by which the ariatolochia clematis, the only British species of this genus, is distinguished. ROOTS. 829 : sweet flags, ^cording to awing ingre- 13'33 I 10 36-67 lant, from the was found to ter colouring of lime. 5. ort. The root since the year The root is Toceeding from a. cd sugar. — opogon muriatus, laa. SeeJour.de IS us that there are e serpentaria w » ■n refer to it. The inff the tocAia after the ariatoloclna a. common trunk, externally brown, and internally whitish. The dried root has an aromatic odour, not unlike that of valerian, and a sharp, bitter, pungent taste, having some analogy to that of cam- phor. It is used as a diaphoretic, stimulating, and tonic medicine. It is useful in dyspepsia when the skin is dry and parched, and is be- lieved to increase the efficacy of cinchona bark. This root was analyzed by M. Chevallier, in 1820*, who ob- tained from it 1 A volatile oil, having the smell of the roots 2 Starch 3 Resin it V A ^ » 4 Gum , * ' 5 Albumen 6 A yellow bitter substance, causing a feeling of irritation in the throat, and soluble in water and alcohol 7 Malate and phosphate of potash 8 A little malate of lime 9 Phosphate of hme 10 Iron 11 Silica. 21. Aristdochia grandijhra of Gomes ; aristolochia cymbifera of Martius. The root of this plant, which is a native of Brazil, is used in that country as a medicine, and is distinguished by the Por- tuguese by the name of Raiz de Mil homens (Root of a thousand men). It is used as an antidote for the bite of a serpent, as an ap- plication to ulcers in the feet, burns, and also in cases of intermit- tent fever. This root was examined in 1833 by M. Rudolph Brandes,t who extracted from it the following substances : — 1 An orange-yellow granular crystalline matter 2 An acid, like benzoic, probably new- Bitter extractive, with various salts Green resin and wax . Sub-resin . Gum .... Brown colouring matter, chlorides 8 Inulin . . . 9 Phosphate of lime 10 Albumen 1 1 Lignin and moisture . with sulphates and") 1-2 0-5 1-8 0-6 1-2 1-4 1-T lOO'O The orange-yellow matter was obtained by digesting the root in alcohol, distilling off the alcohol, and digesting the residue in water. The insoluble portion was treated with ether, a yellow solution was • Jour, de Pharmacle, vi. 565. f Ann. der Pharm. vii. 285. II 1 '!n i '' 1 i u 1 1 ira Ijl 1| .lHHi m. 1 ' W'' ■'1 \ 1 j 'Iw' IB i i ' hmII 1 1 ■■ fjMiM lu 1 r 1 i ' 'H 1 ' 1 1 'i ' '1 f ' 1 1 1 li d, and are said to be emetic, cathartic, and diuretic. The root, in a coarse powder, when taken to the extent of about a scruple, acts as a gen- tle emetic. The root is perennial, strong, divided, and fibrous. When dried it loses its emetic and cathartic properties altogether. This fact, first stated by Decandolle, induced MM. Lassaigne and FeneuUe, to subject it to an analvsis.f They obtained 1 A solid volatile oil < ' 2 A very acrid fixed oil 3 A yellow matter, analagous to cytisite, in which the properties of the root reside 4 Starch ,, 5 Mucus , ■ !, 6 Ulmin • 7 Citric acid 8 Bicitrate and malate of lime 9 An acetate, an ammoniacal salt, and mineral salts. 23. Columbo root. This is the root of tbe cocculus palmattts, a dioecious plant, which grows abundantly in the forests of Mozam- bique, on the east side of southern Africa. The roots are dug up by the natives, in the month of March, and transported to Tran- quebar, where they constitute a staple article of export with the Portuguese. The dried root is brought to this country, packed in bags, and sometimes in cases. It is in transverse sections, generally about jd of an inch in thickness, and one or two inches in diameter. The bark is thick and easily detached, internally bright yellow, and covered with a wrinkled olive-brown cuticle. The inner part of tlie root is pale brown, and has a spongy texture, with dark converging rays. The pieces are frequently much perforated, evidently by worms. This root has a slight aromatic odour, and a bitter taste. Planche analyzed it, and obtained a large proportion of a peculiar azottzed substance, soluble in water, a yellow bitter resinous matter, * The name asarabaeca is made up of the words asarum and baccharis, two genera of plants, that seem to have been confounded together. f Jour, de Pharmacie,vi. 561. » It 1 2 3 4 5 6 7 8 £| 9 10 11 12 A| 13 C Itcoi and tht this voli 25. which is . 'Aful I « given b le ROOTS. Wl • oratigc- tr to that n imprcs- appenred it melted, id over in and ether, lissolve it, •obnbly the t has been ',d, and are in a coarse ;s as a gen- When dried This fact, d Feneulle, [le properties i. s paltnattts^ a ts of Mozam- tB are dug up •ted to Tran- :port with the in bags, and [rally about ^d lameter. The It yellow, and ler part of the tirk converging evidently hy |a bitter taste. of a peculiar lesinous matter, ad baccharis, two and one-third of its weight of starch. By repeated distillations he also obtained a volatile oil, and from the residue, malate of lime, and sulphate of lime. Wittstock discovered in this root a peculiar crystallizable principle, to which he has given the name of colwnbin. The method of obtaining this principle and its properties, have been already detailed in a preceding Chapter of this volume. 24. SaraapariUa.* This is the root of the smilax sarsapariUOf a native of South America, or rather of Mexico. It was brought to Spain about the year 1540, as an undoubted specific in syphilitic disorders, and as a powerful remedy in certain chronic diseases. But European practitioners did not find it to answer the character which it bad acquired in Spanish America. It is still, however, employed, and considered as a valuable remedy in obstinate cases of syphilis. The root is perennial, divided into several branches, which are somewhat thicker than a goose quill, straight, externally brown, iiy temally white, and three or four feet in length. Humboldt informs lis that it is smoked in the drying. It has no smell, but is dis- tinguished by a mucilaginous, very slightly bitter taste. Ganobbio analyzed it, and obtained Acrid and bitter resin . 2*8 , -. Gummy extract . . . 5*5 Starch 54-2 Lignin 27*8 ' 90-3 It has been analyzed also by M. Batka,t who obtained 1 A crystalline matter (smiiacin) 2 A colouring crystalline matter 3 An essential oil 4 Gum 5 Bassorin . .- 6 Starch 7 Albumen . » .. 8 Extractive >; . - . 9 Gluten and gliadin 10 Lignin 11 Pectic acid * 12 Acetic acid 13 Chloride of calcium, potassium, and magnesium Carbonate of lime, oxide of iron and alumina. It contains colwnbin and smiiacin. The method of obtaining which, and their characters, have been detailed in a preceding Chapter of this volume. 25. Ginger. This is the root of the amomum zingiber^ a plant which is a native of India, and was known to the ancients. Pliny * A full account of the different varieties of sarsapaiilla met with in commerce, I is given by Batka, in Ann. der Pharmacia, xi. S05. t Jour, de Pfaarmacie, xx. 43. . 832 ROOTS. M informs) us that it was brought to Rome, in his time, from Arabia, and the country of the Trogloditcs. According to Rumphius, it camo originally from that part of Africa which is adjacent to the Red Sea, and was called zingiber from zingi, the name applied to the inhabitants, bccauao thoy were negroes ; the word zingi signify- ing black. It has been long cultivated in the West Indies, and it is from that quarter chiefly that we are supplied with it. The root is perennial, firm, knotted, of a compressed roundish form, beset with transverse rugro, covered with ash-coloured bark, partljr of a purplish tinge, and sends off many long fibres and offsets. yi' The internal substance of the younger roots is softish, fleshy, and greenish ; of the older it is compact, fibrous, whitish, and when p'^wdered has a yellowish appearance. When the stalks are entirely withered, which happens about the ose of the year, the roots are in a proper state for digging. After being dug, they are picked, cleaned, and scalded in boiling water. They are then exposed to the sun till sufficiently dry, and packed into bags of 100 lbs. each, fur the market. The roots thus pre- pared are called black ginger. White ginger is the roots of the same plant. But instead of being scalded, they are picked, scraped separately, washed and dried with great care. The very hot taste of this root, and the uses to which it is put as a seasoner of food, arc too well known to require any farther notice here. White ginger was analyzed by Bucholz,* who obtained 1'56 Volatile oil Soft acrid resin Extract soluble in absolute alcohol Acidulous acrid extract, insoluble ") in absolute alcohol Gum .... Starch, or rather bassorin . Vegetable mucilage . Apotliemc, soluble in potash Lignin .... Water • . • . 5 3-60 0-65 10-50 12-50 19-76 8-30 26-00 8-00 11-90 102-76 The volatile oil was pale-yellow, very fluid, and had the smell of ginger. The ectractive soluble in absolute alcohol, was soluble also in water, and had an acrid and hot taste. It was afterwards analyzed by Morin,t in 1823, who obtained Volatile oil Acrid soft resin Resin insoluble in ether and oils Gum • >^ Starch Lignin * Taschcnbuch, 1817, p. 62. f Jour, de Pharmacic, ix. 253. ROOTS. 833 n Arabia, oapbluS} it sent to the applied to \gi Bignify- lies, and it id roundish jured bark, and offsets, flesbv, and , and when [\8 about the ;ging. After oiling water. , and packed ots thus pre- roots of the eked, scraped rery hot taste ioner of food, 00 00 90 lad the smell of ol, was soluble fi\vo obtained Vegeto-animal matter / Osmazomo j Acetic acid, acetate of potash, sulphur. The ash contained carbonate, sulphate, and muriate of potash, phosphate of lime, alumina, silica, iron, and manganese. The vegeto-animal mutter of Morin seems to be the same with the acrid acidulous extract of Bucholz. 26. Manioc. This is the root of Jatropha manihot, a plant of South America, from which the variety of starch called tapioca is obtained. This root contains a juice, which the American Indians employ for poisoning their arrows. It was examined in 1836, by MM. O. Henry and Boutron-Charlard,* and found to contain the following substances : — 1 Starch, known by the name of cassava and tapioca 2 Hydrocyanic acia. To which it owes its poisonous jlVoperties 3 A little sugar 4 Magnesia united to a peculiar acid, having an atomic weight of about 4 5 A bitter principle 6 A crystallizable fatty matter 7 Osmazome 8 Phosphate of lime 9 Lignm. The acid, to which these chemists have given no name, crystal- lizes in prisms, has an acid taste, is soluble in water and alcohol, and melts when exposed to a gentle heat into a gummy-looking mass. It forms with lime, barytes, soda, and magnesia, crystallizable salts, which fuse easily, and are not poisonous. 27. Peucedanum officinale. This is a plant which grows wild in England, and is known by the name of sea sulphur wort. The root of it was formerly used in medicine, and preparations from it are still to be found in several of the foreign pharniacopaeias. It was lately examined by Schlatter, who extracted from it a peculiar prin- ciple, to which he has given the name of Peucedanin. He obtained it in the following way : — The root was digested in alcohol ; the tincture distilled to sepa- rate the alcohol ; and the residue left for some time to spontaneous crystallization. The mother water was then decanted off, and the crystals were washed with cold alcohol. They were then dissolved in boiling alcohol. When the solution cooled, transparent colour- less needles were deposited, destitute of taste and smell, but the solution of which, in alcohol, had a very aromatic taste. These crystals melt at 140°, without losing any weight. When the heat is increased they assume a tint of green, and then become greyish-white. They are insoluble in cold water. They melt in boiling water without dissolving. They are but little soluble in iiii, icic, ix. 253. * Jour, de Pharmacie, sxii. 118. 3h nooTS. I ( cold alcohol ; but disRolve readily in that liquid when heated to 140°. The solution is precipitated liv water. Poucedaiiin dis- solves in the fixed and volatile oils. The concentrated acids de- compose it, and the dilute acids do not dissolve it. It is soluble in the alkalies, and precipitated by acids. When assisted by beat il dissolves in carbonates of potash and ammonia, which allow it to be deposited in crystals on cooling. Its alcoholic solution is precipi- tated by acetate of lead, chloride of tin, and suliihate of copper, but not by sulphate of iron.* From those properties it appears more allied to the acids than the bases. It was analyzed in Liobig'g laboratory, during the summer of 1H37, and found composed of 4 atoms carbon . . . =3 2 atoms hydrogen . . . = 0*25 1 atom oxygen . . . =1 4-25 28. Cranieria triandra, or ratanhia. The root of this plant, which is a native of South America, has been introduced into tlit materia niedica of several Continental pharniacopnniiB, mid ismi i-V employed, as yielding a very powerful and safe astringent matter. The root is woody, hard, and round. It is covered with a thid bark, having a reddish-brown colour, and a bitter and astringent taste. The woody portion of the root is yellowish-white and taste- less. The active principles exist in the bark. This root has been analyzed by Trommsdorf, Vogel, and C. G. Gmelin. It contains a species of tannin, which gives a green colour to the pcrsalts of iron. Gmelin obtained Tannin 38"3 Extractive with sugar . . 6'7 Mucilaginous azotic body . . 2*5 Starch 8*3 Lignin 43*3 99-1 Trommsdorf found that 25 of the lignin was soluble in caustic potash, and consequently apotheme, and that its real amount was only 15 per cent. The crameric acid discovered by Peschier has been noticed in the Chemiftry of Inorganic Bodies (vol. ii. p. 107). Some valuable observations on the medicinal preparations of this root, have been published by Subeiranf and Boullay.J 29. Punica granatum, or pomegranate tree. The bark of the | root of this tree was analyzed in 1824, by M. Mitouart, apothecary in Paris. It had been previously employed as a remedy for the teenia. He found it to contain tannin, a kind of wax, gallic acid in abundance, and a sweet->tasted substance, having the characters of * Annalen der Pharmacie, v. 201. t Jour. (Ic Pharmacie, xix. 596. X I^"'* xxi. 4. nooTS. 865 heated to dnnin dis- i ucida dc- s flolublo iu I by beat it low it to bo 1 is preci\ii- copv^F' ^'"^ ppeiirs loore ill Liobi|?'8 posed of 9-1 uble in caustic eal amount vfas by Pescbier has (vol. ii. P- ^^'^} , )aration8 of this y4 :be bark of the luart, apotbecarj I remedy for the ax, gallic acid in the cbaracters ot | XXI. mannite. It was analyzed again by M. Latour dc Trie,* in 1831, who difltinguiHJied in it n pecnliar uulmtttnce, to which he pavo tho name of yrttuidin^ and which he fonsidored us esHontiully ditl'orent from mnnnite. Hut MM. lioutron-Cliurhird and (iuillcniette havo shown that it« pn»i)<«rtieb and couHtitution lU'c absolutely identical with that subHtiiiK o.f 30. Jrisfatidiashna. The root of this plant having been found useful by Dr llacaniicr, in dropsy, M. Lecanu was induced to examine its coronosition. Hu obtiiinod 1 A very acrid volatile oil 2 Itesin • 3 A bitter principle 4 A yellowiah-rcd colouring matter ti Sii'Jir (i (jum 7 A free acid \ 8 Wax !) Salts 10 Lignin.J 3 1 . Liriodendrun tuHpifera. The bark of the root of this tree, originjJly a native of America, but constituting at present a com- mon orni;nient of our shrubberies, especially in the south of Eng- land, was examined chemically by Dr John P. Emmet, Professor of Chemistry and Materia Medicu, in the University of Virginia. He discovered in it a peculiar principle, to which ho' has given the name of liriodendrin, and which he considers as intermediate be- tween camphor and the resins. § The fresh bark of the root of this tree has a pvmgent, aromatic, and bitter taste. When exposed for a few hours to the action of boihng water, or even to the light, its colour deepens, and it be- comes brownish-red. The aqueous solution, on cooling, deposits a little liriodendrin in crystals. The fresh bark contains so much pectate of potash, that its aqueous solution is too viscid to pass through the filter, unless it be precipitated by the diacetate of lead, or somo earthy salt. The easiest mode of obtaining liriodendrin, is to digest the fresh bark for five or six hours in alcohol, heated to 100°, in an opaque vessel. We obtain, in this way, a bitter-tasted solution, which, be- ing filtered, and reduced by distillation to a fifth part of its bulk, lets fall impure liriodendrin when left at rest. Towards the end of the process, the bitter principle separates in drops of an amber colour, which become solid on cooling. The liquid is then eva- porated to the consistence of honey, and a few drops of ammonia being added, the liriodendrin precipitates. The liriodendrin thus obtained is washed with a solution of * Jour, de Pharmacic, xvii. 503, 601. t Jour, dc Pharmacie, xxi. Icy % Ibid. xx. 320. § Ibid. xvii. 400. 836 ROOTS. caustic potash, till water ceases to be coloured by it. In this state it contains water, and is softened by the heat of the hand. A tem- perature a little higher gives it an aromatic odour, and it melts like a resin. On cooling, it concretes into a brown substance, having a specific gravity of 1*097. Its taste is bitter and aromatic, but not strong, on account of its insolubility in water. The alcoholic solution is very bitter and acrid. But when the liriodendrin is crystallized, this acrid taste disappears. Dr Emmett obtained this substance in crystals, by the following process: — The re- sinous liriodendrin was dissolved in alcohol, the solution was heated to the temperature of 100°, and water of the same tempera- ture was added slowly, till the liquid assumed a milk-white colour. It was then filtered and set aside. On cooling, the liriodendrin was deposited in crystals. These crystals were rendered quite pure by subjecting them to pressure between folds of blotting paper. In this way it is obtained in scales like boracic acid, or in needles, according to the slowness of its cooling. These crystals are transparent and colourless. Liriodendrin thus crystallized, is scarcely soluble in cold water, but it communicates a bitter taste to hot water. Alcohol and ether are its best solvents. These solutions are colourless, and possess neither acid nor alkaline properties. Nitric acid dissolves it in great abundance without altering its colour, and it may be evapo- rated to dryness without alteration. Strong sulphuric acid dis- solves it immediately, and assumes a deep reddish-yellow colour. The liriodendrin is converted into a resin which may be sepa- rated by water. Cold muriatic acid has little effect, but when assisted by heat it decomposes liriodendrin, and a green matter re- mains. Iodine gives it instantly a yellow colour like that of chromate of potash. The most minute quantity of liriodendrin may be detected by this reagent. Chlorine converts it into a bitter-tasted resin. When it is triturated with mucilage of gum arable the bitter taste disappears, and when the solution is left at rest, it deposits crystals different from those of liriodendrin. The crystals of liriodendrin melt when heated to 180°. At a little higher temperature it begins to sublime. A dense aromatic vapour rises and condenses into a transparent colourless varnish. The point of volatilization is so very near that of decomposition that we cannot volatilize it. When the crystals are heated in a glass tube, water separates from them before they melt. The products of the decomposition of this substance contain no traces of benzoic acid or ammonia. 32. Iris lattfolia 'dxid angustifolia. The roots or rhizomas of these plants have been analyzed by M. Lecoq,* who obtained * Jour, do Pharmacie, xlv. 221. ROOTS. 837 In December. In April. 73-0 12-5 1*5 13-0 73-0 10-8 3-2 13-0 100 100 Water . . Fecula . . Gum . . Sugar . Tannin . Bimalate of lime Extractive Albumen trace Lignin . 33. Asparagus officinalis. The root of this well known plant was examined by M. Dulong d'Astafort. He obtained Albumen Gum A substance precipitated abunUantly by subacetate of lead and nitrate of mercury A rep'.n Sugar, reddened by sulphuric acid Supermalates N Wef }of potash and Itoe Phosphates J Iron.* 34. Convolvulus batata. The root of this plant, which is a native of the West Indies, though it has been naturalized in Spain and the south of France, is used as an article of food. It was ana- lyzed by M. O. Henry, who found it to contain Starch 13*3 Water . . . , Albumen Incrystallizable sugar Volatile poisonous matter Peculiar fatty matter , Parenchyma . Malic acid and salts . 73-12 0-92 3-30 0-05 M2 6-79 1-40 •Mi m 100-OOt - 35. Comus florida. The bark of the root of this tree, which is a native of North America, is used as a febrifuge. It was analyzed by M. Geiger,:^ who found it to contain 1 Comic acid 2 Tannin 3 A peculiar resin, crystallizing and neutral I! * Jour, de Pharmacie, xii. 278. f Ibid. xi. 233. 'j: Annalen der Pharmacie, xiv. 206. in ii 833 BULBS. 4 Oxalate of lime, with another calcareous and magnesian salt, containing malic aciil, and perhaps phosphoric 5 Two ditt'crent colouring matters, the one soluble in acids, and insoluble in alkalies • 6 Gum • " 7 A little starch. CHAPTER VI. OF U U L 15 S. Bv bulbs are understood tubercles connected with the roots of vegetables, very analogous to the buds, and containing the em- bryo of a future plant. The potatoe is a well known example of a bulb. Several bulbs are composed of concentric coats, like the onion, while some are imbricated somewhat like the artichoke. Several bulbs, as the potatoe, onion, &c., are used as nutritive articles of food ; while some, as the bulbous roots of the cokhicum autumnale, constitute active medicines. 1. Potatoes are the bulbs of the solanum tuberosum, an American plant which is said to grow wild in the mountainous regions of Peru and Chili ; and from the name, Virginia potatoes, applied to them when they began to be cultivated in the neighbourhood of London, one would suppose them to have been indigenous in North America, though this has not been confirmed by recent botanical travellers. They are said to have been first introduced into Ireland by Sir Walter Raleigh, in 15()5 ; and from thence into England, by a vessel wrecked on that part of the west" coast, called North Meols, in Lancashire. About the year 1605, they began to be cultivated in the neighbourhood of London, and were occasionally presented on the table as great rarities. In the year 1663, Mr. Buckland, a Somerset gentleman, wrote a letter to the Royal Society, recommending the planting of potatoes in all parts of the kingdom, to prevent famine. This was referred to a committee, who ap- proved of the proposal, and agreed to recommend it with all the influence of the Society.* But many years elapsed before their cultivation in Great Britain became general. In France they may be said to have been brought into general use by the indefatigable exertions of Parmentier, about 1773. In Sweden they were re- commended by a royal edict in 1 764, and came very slowly into general use. Potatoes have been repeatedly subjected to chemical examination. Parmentier published an elaborate dissertation on their culture, * Birche's Hist, of the Royal Society, i. 213. ^nesian salt, in acids, and the roots of inini^ the em- . example of a .ike the onion, oke. Several tive ai'ticles of um autumnale, 1, an American •egions of Peru ,pplied to them )od of London, Jorth America, lical travellers. Ireland by Sir Ennjland, by a d North Meok, be cultivated nally presented Mr. Buckland, loyal Society, of the kingdom, littee, who ap- it with all the ed before their 'ranee they may he indefatigable n they were re- eery slowly into cal examination, n their culture, 3. BULDS. 839 uses, and propt »3, about the year 1776, which contributed con- siderably to pr )iuote the cultivation of them on the continent. Dr Pearson contributed to the Board of Agriculture a valuable essay on potatoes, containing a set of chemical experiments on them, per- formed with his usual skill and ingenuity ; and Einhof has published a very elaborate analysis of the root in the fourth volume of Geh- Icn's Journal. The variety of potatoe which chiefly occupied the attention of Einhof, was that which has a red skin, and flesh-coloured juice. When dried by a moderate heat, till they ceased to lose any weight, potatoes were reduced to ^th of their original weight.* The analysis of this root was conducted by Einhof pretty much in the same manner as his analysis of barley and rye. A deter- minate quantity of potatoes was reduced with water to a pulp, and then washed on a scarce till the liquid ceased to come ofl^ milky, or to hold any thing in solution. What remained on the cloth was the Hbrous matter of the potatoe ; but it differed essentially from the fibrous matter of most plants. With boiling water it formed a paste similar to that made by means of starch, and when dry it as- sumed a semitransparent appearance. This matter, when triturated in a mortar, and again washed with water, yielded a considerable portion of starch. The residue, which was of a light-grey colour, being triturated a second time, formed a powder, which bore a con- siderable resemblance to starch, both in its appearance and proper- ties. The liquid with which the potatoe was washed was at first milky, but deposited, on standing, a heavy white powder, which was starch. When filtered, it had a carmine-red colour, and reddened vegetable blues. When boiled, a flaky precipitate separated, partly white and partly red. This precipitate possessed the properties of albumen. The residue, evaporated to the consistence of an extract, had a brownish colour, was insoluble in alcohol and ether, soluble in water, and, according to Einhof, was a mucilaginous matter. The following were the proportions of these various substances, obtained from 100 parts of potatoes : — Starch 15 Fibrous starchy matter . . 7 Albumen 1*4 Mucilage, in the state of a thick syrup 4 27-4 To ascertain the nature of the acid which exists in potatoes, Einhof separated the juice of potatoes by a gentle pressure. He had first frozen and then thawed them, to facilitate the separation. Lime-water was added in excess to this liquid, and the precipitate was digested in diluted sulphuric acid, to separate the lime from the acid. Thus obtained, it was found to be a mixture of tartaric and * Gehlen 8 Jour. iv. 457. J m 'i;' '.t\ i* 1 i '1 840 BULBS. phosphoric acids.§ The sap, thus deprived of its acid, contained an excess of lime, in combination with the mucilage. Einhof found, that this lime became gradually saturated with carbonic acid, even though the sap was kept in close vessels; and that in process of time, if a sufficient quantity of lime were present, the mucilage ac> quired a sweet taste ; and when treated with alcohol, a portion dis- solved, which yielded crystals of sugar. This he considered as a conversion of the mucilage into sugar. From 1820 parts of dried potatoes, Einhof obtained 96 parts of a greyish-white ash. Of these, 64 parts were soluble in water. They consisted chiefly of carbonate of potash ; but contained like- wise 10| parts of phosphoric acid, 3^ of sulphuric acid, and 2 of muriatic. The insoluble 35 parts consisted of earths and oxides. From 20 parts of it he obtained 2*5 silica 6*0 lime 4*0 alumina 7*0 magnesia, with some manganese or oxide of iron 19-5 Einhof examined different kinds of potatoes. He found the same ingredients in all, but the proportions varied considerably. The following table exhibits the constituents of different varieties of potatoes, according to the analyses of Einhof, Lampadius, and Henry, jun. Kinds. starchy Fibrin. Starch. Albumen. Gum. *tr' water. Red potatoe* 7-00 15-00 1-40 4-1 5-1 75 Do. after budding* 6-80 15-20| 1'30 3-7 73 The buds or germs* 2-80 0-40 0-40 3-3 93-1 Great red potatoe* 6-00 12-90 0-70 — 78 Kidney do.* 8-80 9-10 0-80 — 81-3 Sweet do.t . 8-20 15-10 0-80 — 74-3 u.-v^ Peruvian potatoef 5-25 15-00 1-88 1-87 76 English do.f 6-83 12-91 1-04 1-70 77-8 Onion do.f . 8-38 18-75 0-9 1-66 70-3 Voichtland do.f . 7-13 15-41 1-25 1-95 74-3 Paris do4 . 6-79 13-3 0-92 1-4 73-12J Besides the substances detected by Einhof and Lampadius, Vmi- quelin discovered, in the expressed juice of the potatoe, about 0*1 § Though Einhof obtained phosphoric acid by the method described in tlic text, it does not follow that it existed in the potatoes in an uncombined state. It might have been in combination with lime, and held in solution in the potutuc juice by means of tartaric acid. • Those marked • analyzed by Einhof. •j" Those marked f , by Lampadius. Schweiggcr's Jour. ix. 362. J Henry, junior. 'K sontained lof found, Lcid, even process of cUage ac- ortion dis- lered as a )6 parts of I in water. ;ained like- i, and 2 of and oxides. on ind the same ibly. rent varieties mpadius, and aUn. 5-1 I 75 73 1 93-1 1 78 1 81-3 74-3 176 1 77-8 I 70-3 174-3 1^.4_73^12; .tnpadius, Vmi- itoe, about O'l described in ilic ombined state, u ■on \n the potatoc 362. BULBS. 841 per cent, of crystallized asparagin ; abou' 0'4 or 0*5 per cent, of a substance containing azote, similar to gum, and not precipitated by tannin ; a soft resin, which, when heated, emits an agreeable smell ; an extractive substance, which becomes black when exposed to the air ; citric acid ; citrates of potash and lime, and phosphates of the same bases.* Baup informs us, that potatoes, after they begin to grow, contain a small quantity of solanin. As it may be useful to know the quantity of starch furnished by different varieties of potatoe, the following table drawn up from the experiments of Mr William Skrimshire, junior, is subjoined. Five pounds avoirdupois of fresh potatoes were used, and the starch was separated by grating the potatoe, and pouring water upon it placed upon a searce.f Substances. Varieties of Potatoes used. • •s • J % 1 • w • (Xi ^ a t "O « 3 1 1 s o 1 1 4) I o M o lb. oz. lb. oz. lb. oz. lb. oz. lb. cz. b. oz. lb. oz. lb. oz. Fine starch . . 9 7i 9 %\ %\ 8 ^ Ditto, slightly 1 coloured . . ! 3 3i 9J 2} 2^ OJ 0^ 1} Pulp dried . . 6 6J 3J b\ 6^ U 6f 5 8 Water, mucus, ? and extractive J 3 14 3 15 4 2J 3 14J 3 14;^ 4 Oi 4 n 3 15J ! Total ..50 50!50'50I50 50 3 5 When potatoes are exposed to the action of frost, it is well known that they become soft, and acquire a sweet taste. This taste is succeeded by a sour taste, owing to the rapid evolution of acetic acid, and the root soon passes to putrefaction. From the experi- ments of Einhof, we learn that the sugar is formed at the expense of the mucilage ; for the other ingredients were found, in potatoes sweetened by frost, in the usual proportions. He considers this sweetening process as connected with the vegetative powers of the root. When potatoes are boiled, they lose from 1 to 1^ per cent, of their weight. The juice, which may be separated from them, is sweet-tasted. The meal is insoluble even in boiling water, though potatoe starch forms a transparent solution with hot water. Thus it appears, that by boiling, the albumen, fibrous matter, and starch combine together, and form an insoluble compound.^ • Jour, de Phys. Ixxxv. 1 13. f Nicholson's Jour. xxi. 71. X Gehlen's Jour. iv. 485. 11 ^Tii Wi X\- 842 BULBS. From these experiments, it appears that potatoes differ essentially from wheat and barley, by containing no gluten. They approach, in some measure, to the nature of rye. Dr Peschier, of Geneva, has detected the presence of mucous sugar and of gum in the potatoe. This explains why they arc capable of undergoing the vinous fermentation.* 2. Jerusalem Artichoke. This is the bulbous root of the helian- thus tuberosus, a plant which grows wild in several parts of South America. It has somewhat the shape of a potatoe ; but the tubers are smaller. They have a slightly sweet taste, and are very watery. The helianthus is very productive, and when once planted, they continue to grow in the same place, year after year, without any trouble whatever. An acre is said to yield from 60 to 70 tons tJt' them. We have three analyses of this valuable bulb ; one by Zenneck iu 1823 ;t another by Braconnot, in 1824$ ; and a third by Payen, iu the same year.§ Zenneck obtained' Green starch .... 6*5 Bitterish sweet extractive . . 1*4 Bitter and saline extractive not solu- ble in alcohol . . . . 4*0 Lignin 8*0 Albumen . . , . , 0*4 Water with a little volatile oil . 73'0 Braconnot obtained Water .... Liquid sugar . . . Inulin .... Vegetable skeleton Gum .... Citrate of potash Peculiar substance || . Ferruginous phosphate of lime Sulphate of potash . Citrate of lime . Chloride of potassium Phosphate of potash . Oil, very soluble in alcohol and Cerin .... Malate of potash . . 93-3 Tartrate of lime . 77-2 . 14-8 30 1-22 1-08 1-07 0-99 0-14 0-12 0-08 0-08 0-06 potash 0'06 0-03 0-03 0-12 0-07 100-15 * Annals of Philosophy, xii. 337. f Schweigger's .Tahrbuch, \x. 315. X Ann. dc Chim. et de Phys. xxv. 358. § Ibid. xxvi. 98. II It |)Toduccs viscous icrmentation. BULBS. 843 iasentially approacb, jf mucous r they avc the helim- ta of South i the tubers ery vratery. [anted, they without any J 70 tons of ' Zenneck in jy Payen, in > 4 •0 •4 •0 J-3 2 8 •0 •22 •08 •07 1-99 14 •12 •08 •08 •06 •06 I0-03 |0'03 lol2 10-07 I .Tahrbuch, «• 315- Ibid. xxvi. 98. When the bulbous roots of the Jerusalem iii'tichokc arc bruized, and expressed, a mucilaginous liquid is obtained, having a specific gravity of 1'0995 as determined by Piiyen. This liquid is colour- less, but speedily becomes brown when exposed to tlie air, but this is prevented by the addition of a little sulphuric acid. When heat- ed to 212° it coagulates so strongly that it may be employed to clarify other liquids. .The .albumen thus deposited carries with it a little fixed oil, which may be separated by alcohol, and is com- posed of elain and stearin concreting at GO". Tiie alcohol at the same time dissolves a certain quantity of gluten. Payen found that the bulbous roots bruised and mixed with hot water and yeast fer- ment, and produce a quantity of anhydrous alcohol, amounting to 9 per cent, of the weight of the bulb employed. 3. Garlic. This is the bulbous part of the root of the allium sativum, a plant which grows spontaneously in Sicily, and is well known, and remarkable for its strong smell and peculiar taste. It was much celebrated by the ancients, both as an article of food and as a medicine. It has been repeatedly examined by chemists. The analysis of Neumann, considering the state of the art of ex- amining vegetables at that time, must be considered as very exact.* Cadet has subjected it to a chemical examination.t When dried, it loses nearly §ds of its weight ; but this proportion is doubtless subject to considerable variation. The expressed juice of garlic is of a thick consistence like mucilage, and slightly reddens vegetable blues. When diluted with water, and filtered, it yields flakes of albumen when boiled. The residue consists chiefly of mucilage, of which garlic yields a very great proportion, and of ex- tractive. This last is somewhat acrid in its nature. When garlic is distilled with water, it yields a portion of yellow-coloured volatile oil, at first lighter than water, but gradually becoming heavier as the distillation advances. To this oil garlic owes its most remarkable properties. Its taste is very acrid, and its smell strong. When applied to the skin, it produces an irritation not inferior to cantha- rides, and, like that drug, might be employed to blister the skin. When triturated with oxide of iron, it immediately strikes with it a black colour ; but it has no effect upon any other metallic oxide. When garlic is treated with alcohol, the liquid assumes a reddish- yellow colour, and leaves, when evaporated, a brown extract, very acrid, which attracts moisture from the air. When garlic is distilled, it yields first a liquid slightly coloured, and having a very acrid taste ; then a thick brown oil, and abund- ance of inflammable air and carbonic acid. The liquid in the re- ceiver emits the smell of ammonia when mixed with lime. When 40,320 parts of garlic were incinerated, they left 4896 parts of ashes, or about ^th of the original weight. From 172 parts of these ashes Cadet cl jtained the following substances : — * Neumann's Chemistry, p. 431. f Ann. dc Chim. lix. 106. 844 { BULBS. Fotaah .... • 33-0 Sulphate of potash with some muriate 58*0 Alumina .... 20 Phosphate of lime 16-6 Oxide of iron . . 1-5 Magnesia . 9*0 Lime .... 14-0 Silica . . . 8-0 14M ^rora 1406 parts of fresh garlic he obtained Mucilage .... • 520 Albumen .... • 37 Fibrous matter . • 48 Water, by estimate • 801 1406 Bouillon-Lagrange has detected in garlic, besides the acrid oil, a quantity of sulphur, starch, and saccharine matter.* 4. Onion. This is the bulbous root of the allium cepa. A few experiments on it had been made by Neumann and Cadet. But Fourcroy and Vauquelin published the first accurate analysis of it. When reduced to a pulp, and subjected to the press, it yields a viscid juice, somewhat opaque, at first colourless, but becomin Adipocire j * * ' 0-18 Phosphate pf lime Sulphate of potash . O'lO 0-04 Makte of potash 0-04 Phosphate of potash . , 0-02 Muriate of potash . . 0-02 Odorous principle — 100-OOi 8. Bulbs of the oralis crenata. Th ese bulbs, accoi analysis of Payen, contain Water . 86 Starch . . . . 2*5 Albumen . 1-5 Mucilage and salts . 5-55 Lignin and silica 4-44 100-Ot He afterwarwards found, that in other specimens the proportion of starch was greater. * Beri. Jabrb. xx. 185. t Annals of Philosophy, xiii. 70. X Ann. der Pharmacie, xv. 160. r m 848 WOODH. From the stems of the same plant Payen obtained Woter 95-2 to 88'6 Lignin 2*00 — 5*0 An oxalate .... I'OQ — 1-23 Albumen .... 0-40 — 75 A soluble substance, containing azote 0*60 — 0*75 Chlorophyllo .... O-OG — O-IO Oxalate of ammonia, ocid salts, 7 1.03 o.qo gum, and uroma . 100-60 98'43» CHAPTER VII. OF WOODS. The wood of different trees differs materially in hardness, strength, durability, and beauty. But from the experiments of Count Hum- ford, there is 'reason to believe that the mere woody fibres of all plants are nearly the same, and that the differences are owing al- most entirely to the various proportions of liquids and empty spaces with which the woddy fibres are intermixed. He found the specific gravity of the wood of different trees as follows: — 1-4854 1-4846 1-4848 1-4621 1-4599 1-5284 1-5186 1-5344 poplar consisfed respectively of the fol- Poplar Lime Birch Fir Maple Beech Elm Oak A cubic inch of oak anc lowing proportion? of wood, sap, and Wood. Sui-. A'r Oak . . 0-39353 . . 0'-M\\lz . . 0-k4.>25 Poplar . . 0-24289 . . 0-21880 . . 0-53831 He found likewise that the same tree in winter contains more sap than in summer ; and that in summer it contains more air than iu winter.f ' TM. P'^-erscn and Schbdler made an important set of experi- juents on the analysis of the different kinds of wood, in Liebig's iaboratory in 1835, t in order to determine their relative value as firewood. The wood of the different trees (just as they had been • Ann. der Pharmncie, xv. 160. f Nicholson's Jour, zxsiv. 319. X Ann. dcr Pharm. xvii. l.?9. WOODS. 849 6 •0 •23 I 75 ►•75 )10 2-00 8-43* eas, strength, Coiivit llum- y fibres of all are owing al- l empty spaces nd tlie specific 54 46 48 21 99 84 86 44 vely of the fol- 0'*z4.>25 0-53831 Utains more sap lore air than ui It set of expcri- lood, in Liebigs Ir relative value las they had been jur . xxxiv. 319* felled) was reduced to n fin*' pow>l(T, dried at 2l2o, mixed with oxide of copper, and analyzed " the umuaI itav. From the (quantity of water and carbonic hoi J obtained, the hydrogen wa» c«tiMiut oxygen in that smiill propor- tion. The following table shows thu results obtained : — Wood*. t«Tbon. Hjrdrogt'ti. oxrgt-fl. 44-499 {, iiercus robur 49-432 6-069 F IS sylvatica, a. Red 48-184 6-277 45-539 U tto6. White 48-533 6-301 45-166 Betula alba .... 48-602 6-375 45-023 Hetula alnus .... 49-148 6-217 44-587 Pinus larix .... 50-106 6-310 43-5H4 Pinus abies .... 49-946 6-407 43-647 Pinus picea .... 49-591 6-384 44025 Pinus sylvestris 49-937 6-250 4 -^813 Prunus domesticus 49-311 5-964 44-725 Prunus cerasus 48-824 6-276 44 900 Pyrus malus 48-902 6-267 44->3I Pyrus communis . 49-395 6-351 44-l'54 Diospyros ebeniim 49-838 5-352 44-8 J Buxus sempervirens 49-368 6-521 44-111 Ulmus suberosa 50-186 6-425 43-381) Populus nigra 49-699 6-312 43-989 Fraxinus excelsior 49-356 6-075 44-569 Juglans regia 49-113 6-443 44-444 Robinia Pseudacacia 48-669 6-272 45-059 Tilia Europsea 49-408 6-861 43-731 iEscnlus hypocastanum . 49-077 6-714 44-209 Salix fragilis 48-839 6-360 44-801 i Acer campestris 49-803 6-307 43-890 The vegetable Jibres in herbaceous plants correspond with the wood of trees. In some it is so brittle as to be easily broken, while in others it i» flexible and tough ; as in hemp, nettles, lint, &c., but in these perhaps the fibres ought to be considered rather as the liber or inner bark, than the wood. To separate hemp and flax from the stems which contain them, the plants are steeped in stagnant water, till they undergo a species of putrefaction, which destroys the glutinous matter which cements the fibres to the pUnt. They are then spread upon the grass till they become quite dry. By these processes the stalks are rendered I very brittle, (a// !mt thejihres) and when passed between rollers and struck by scutches, the whole vegetable matter is driven ofl^, and nothing remains but the hemp or lint, in the state of grey-coloured land tough fibres. These fil»res are afterwards bleached white. Mr James Thomson and Mr Bauer have shown that the fibres 3 I hh {\ 850 WOODS. 1 mi 1 1 of flax are transparent cylindrical tubes, articulated and pointed like a cane : while the filaments of cotton are transparent glassy tubes, flattened and twisted round their own axis. A section of a filament, resembles, in some degree, the figure 8, the tube originally cylindri- cal, having collapsed most in the middle, forming semitubes on each side, which give to the fibre, when viewed in certain lights, the appearence of a flat ribbon with a hem or border on each edge. The uniform transparency of the filament is impaired by small irregular figures, probably wrinkles arising from the desiccation of the tube.* In consequence of this diff'erence between the structure of linen and cotton fibres, Mr Thomson and Mr Bauer were enabled to ascer- tain, that the cloth in which the Egyptian mummies are wrapt, is always linen and never cotton. It is clear from this, that the opinion entertained by some, that what is called in our translation of the Old Testament ^we linen of Egypt, ought to be fine cotton cloth of Egypt is erroneous. We have no evidence from the cloth wrapt about ancient mummies, that the Egyptians in these early times were acquainted with cotton.f Cotton is a soft down which envelops the seeds of various plants, especially the difierent species of gossypium, from which the cotton of commerce is procured. These plants are natives of warm climates ; grow wild in Asia, Africa, and America, within the tropics ; and are cultivated in the East and West Indies. The finest cotton, according to Mr Edwards, is distinguished by the name of green seed cotton^ from the colour of its seeds,t and is perhaps tho produce of the gossypium hirsutum. There are two species of it ; in one of which the cotton does not easily part from the seeds. But the cotton plant commonly cultivated is a shrub, of which Mr Edwards enumerates five kinds ; namely, the common Jamaica^ the brown bearded^ the nankeen, the French {gossypium arboreum), and the kidney cotton.^ When the seeds are ripe, the pods open and display the cotton, which is collected and separated from the seeds by means of rollers. Cotton, when spun and woven into cloth, furnishes garments to a very considerable portion of the civilized world. The quantity annually brought into this country, and spun by machinery, is not less than 60,000,000 of pounds; and the number of individuals employed in manufacturing it cannot be fewer than 2,000,000. It constitutes therefore one of the most important of our manufactures. Cotton is tasteless and destitute of smell. It is completely in- soluble in water, alcohol, ether, and oils, and in all the vegetable acids. The diluted alkaline leys have no perceptible action on cotton ; but when very strong, they dissolve it if assisted by a sufficient * Phil. Magazine, (3d series) v. 355, for 1834. •{■ The Hebrew word for linen cloth is »nD> hence the amiuv of the Greeks. J History of the West Indies, ii. 2C4. § Perhaps the first species arc only varieties of the gossypium herbaceum. WOODS. 851 i pointed like glassy tubes, I of a filament, nally cylindri- itubes on each lin lights, the ;h edge. The small irregular n of the tube.* re of linen and ibled to ascer- es are wrapt, is that the opinion mslation of the le cotton cloth of the cloth wrapt early times were if various plants, which the cotton jf warm climates; the tropics; and 'he finest cotton, le name of green fhaps the produce fs of it ; in one of seeds. But tlie fich Mr Edwards ..laica, the brown \boreum), and the 3 open and display [le seeds by means lishes garments to i. The quantity machinery, is not )er of individuals in 2,000,000. It our manufactures, is completely in- all the vegetable I action on cotton; ted by a sufficient b«» of the Greeks. h/piwn herbaceum. degree of heat. The new products obtained by this solution have not been examined. Cotton has a strong affinity for some of the earths, especially for alumina. Hence this substance is used to fix colours on cotton. The cloth is steeped in a solution of alum or acetate of alumina, and afterwards dyed. Several of the metallic oxides also combine with it readily, and remain united with much obstinacy. Oxide of iron is one of the most remarkable. When cotton is dipped into a solution of iron in an acid, it comes out yellow, and the iron is neither separated by al' alies nor soap, nor even by acids, unless when the combination is recent. The colour gradually deepens by exposure to the air, owing no doubt to the oxidizement of the iron, unless the cloth be steeped in an aluminous solution, which prevents the colour from becoming disagreeable, probably by diluting it.* Oxide of tin also combines with cotton, and is frequently used as a mordant. Cotton combines readily with tannin, and forms a yellow or brown compound. Hence the infusion of galls, and of other astringent ' substances, is often used as a mordant for cotton. Nitric acid de- composes cotton when assisted with heat, and oxalic acid is formed ; the other products have not been examined. Sulphuric acid like- wise chars it. Chlorine gas bleaches it, and probably alters and dissolves it when applied in a concentrated state. Cotton is ex- tremely combustible, and burns with a clear lively flame. The ashes left behind, according to Neumann, contain some potash. When distilled it yields a great portion of acidulous water, and a small quantity of oil, but no ammonia.f Paper is prepared from hemp, linen, and cotton rags. These i'ags are bleached, reduced to an impalpable pulp. This pulp is spread equally by means of water on a wire gause frame, which allows the water to run off". The paper then is left to dry. To render it fit for writing upon, the pores which it naturally contains must be filled up. This is accomplished by dipping each sheet into a solution of glue and alum, an operation which is called sizing. This renders the paper impenetrable to liquids. Filtering paper must not be sized. Much of the white coarse paper made in this country is filled up with sulphate of lime, which gives it an appear- ance of much greater strength and thickness than it really possesses. Such paper cannot be employed for filtering. 40 grains of good filtering paper contains at an average ^d of a grain of ashes. But in some of the paper made up with sulphate of lime, I have found as much as 17 grains of residue in 40 grains of the paper. Silk paper is very light but contains much ashes. The light red-coloured blotting paper, so common in this country, is a cotton paper formed from the rags or shreds of turkey-red cloth. It owes its red colour to the madder dye. Paper, such as we use at present, was unknown to the ancients. * See Cliaptal, Ann. do Cliiin. xxvi. 266. f Neumann's Clieni. p. 430, »l"^' |t.| M ■ I i 4 ■I- > *N 1 "m ! t»! 852 WOODS. It seems to have been an Arabian invention. It is supposed that the Arabians were acquainted with paper, from cotton rags, as early as the year 704. But the art was known and practised at a much earlier date in China. From the researches of Montfauqon, we learn, that cotton paper was used in Europe as early as the end of the ninth century. The only kinds of wood which have been subjected to chemical experiments, are those which are employed in dyeing. For an ac- count of these the reader is referred to a previous Division in this volume, in which these different woods are described in detail. But as wood is much employed for fuel, the following table from the experiments of MM. Peterson and Schodler showing the quan- tity of oxygen required for burning 100 parts of various kinds of wood is important, as this oxygen is proportionable to the quantity of heat evolved by each.* VamMnfTrPM. OxyROn to bum Names or 1 reel. ,yy ^f ^^^^ Tilia Europea, /me . . 140*523 Ulmus suberosa, elm . . 139*408 ', Pinus abies,^r . . . 138*377 Pinus larix, larch . . 138*082 ^sculus hippocastanum, horse- chesnut .... 138*002 Buxus sempervirens, 6o« . 137*315 Acer campestris, mapple . 136*960 Pinus sylvestris, (Scofc/i jfir . 136*931 Pinus picea, pitch pine . 136*886 Populus nigra, WacA ^op/or . 136*628 Pyrus communis, />ear ^rce . 135*881 Juglans regia, walnut . . 135*690 Betula alnus, alder . . 133*959 SaWx fragWia, willow . . 133*951 Quercus robur, oak . . 133*472 Fyrus m&\us, apple tree . 133*340 Fraxinus excelsior, ash . 133*251 Betula alba, birch . . 133*229 Prunus cerasus, cherry l. f Aim. dc Cliirn. Ixv. -ll-l. X J^''^^' '*"• 33- '. * i'v'; fi 1 890 LEAVBS. , i in i 11 In 1819 it was analyzed by Brandes, who discovered in it a vegetable alkali, to which it owes its peculiar properties, and which he distinguished by the name of atropina. He obtained from the leaves of belladonna, the following constituents • Wax . 0-7 Chlorophylle . 5-84 Pseudotoxin* . 1605 PhytocoUaf . 6-90 Gum 8-33 Starch . 1-25 Albumen 10-70 Lignin . 13-70 SaltsJ . 7-47 Water . 25-80 96-74 Some years ago, M. T. Schmidt of Berlin, observed crystals in the extract of belladonna. He mentioned the circumstance to M. Blitz, of Erfurd, who ascertained that these crystals consisted of asparagin.§ Atropina has been described among the vegetable alkalies in a preceding Chapter of this volume. 3. Tobacco. This substance is formed from the leaves of the nicotiana tabacum, a plant which is a native of Virginia, where it is cultivated very extensively for the purposes of commerce. Its name was given it from Tabaco, a province of Mexico, where it was first observed, and whence it was originally brought to Europe.]! Tobacco, when properly cured, has a yellowish-green colour, a strong and rather unpleasant smell, and a very acrid taste. When burnt it emits a strong odour, which to many is peculiarly grateful. When swallowed, it acts very violently upon the system ; and when taken in sufficient quantity, proves fatal. Vauquelin subjected the leaves of different species of nicotiana particularly the latifolia, to analysis. The expressed juice contained the following substances :— A considerable quantity of vegetable albumen or gluten Supermalate of lime Acetic acid A notable quantity of nitrate and muriate of potash * This is a substance soluble in alcohol, and containing azote. It was not free from salts, among which were malate of atropina, with oxalate, muriate, and sulphate of potash. f This is a substance insoluble in alcohol and containing azote. % The salts were malate of atropina, and sulphates, nitrates, phosphates, ace- tates, and muriates of potash, ammonia, lime, magnesia. § Jour, do Pharmacie, xxi. 178. II For a detailed account of the culture and management of tobacco, see Taiham's Essay on its culture and commerce, published in 1800. Tlie tobacco of Schiraz, in Persia, is most highly esteemed of all. It has been described by Mr Lindlay, as a new species under the name of ntco^tana Persica. See Horti- cultural Trans, (new series), i. 205. LEAVES. 857 ered in it a IS, and which led from the 4 5 3 55 fO ro 17 30 74 ved crystals in Lmstance to M. lis consisted of le alkalies in a le leaves of the rinia, where it is lerce. Its name rhere it was first Europe.ll .green colour, a id taste. When culiarly grateful, stem -, and when [in subjected the / the latifolia, to [no- substances :— gluten tash , azote. It was not [oxalate, muriate, and kzote. Ites, phosphates, ace- Lent of tobacco, see L 1800. The tobacco (as been described by Ipersica. See Horn- A red matter soluble in alcohol and water which swells consider- ably when heated Muriate of ammonia Nicotina Green fecula composed chiefly of gluten, green resin, and woody fibre.* The most recent analysis of the leaves of this plant is by MM. Posselt and Reinmann.f They obtained Nicotina Nicotianin Extractive slightly bitter Gum, with a little malate of lime Green resin Albumen Gluten . Malic acid Malate of ammonia Sulphate of potash . Chloride of potassium Malate and nitrate of potash Phosphate of lime \.].m Malate of lime Silica Liguin . Starch, a trace Water . 0*06 0-01 2-87 1-74 0-267 0-26 1-048 0-51 0-12 0-048 0-063 0-095 0-166 0-242 0-088 4-969 88-280 100-956 4. Digitalis purpurea, or Fox-glove, The leaves of this indigen- ous plant, too common to require any description, were introduced into the Materia Medica by Dr Withering, as a diuretic. It had been used before occasionally as a sedative. But its diuretic properties, for which at present it is chiefly valued, seem to have been discov- ered by Dr Withering. The leaves should be gathered when the plant is in flower, and those only selected which are fresh. The leafstalks and midribs should be rejected, and the leaves dried by exposure to the sun, or hung up separately till they dry in a warm kitchen. When fresh they have no smell ; but when dried acquire a weak narcotic odour, and have a bitter nauseous taste. Both water and alcohol extract their virtues. The dried leaves should have a beautiful green colour. When triturated with lime they give out ammonia. These leaves have been analyzed by MM. Rein and Haase, and still more lately by Welding.^ He obtained 1 Gallic acid 2 Mucus * Ann. de Chim. Ixxi. 139. f Mag. Pharm. xxiv. 138, and xxv. 2, j7. X Ann, der Pharmacie, xiii. 212. .- II ^1*, ; Ar,' 858 LEAVES. A 3 Red colouring matter, soluble in water, but not in ether or alcohol 4 Chlorophyllo 6 Sugar G Starch, a trace 7 Volatile oil 8 A fixed flocky substance 9 Gum 10 A fatty substance 1 1 Extractive 12 Digitalin 13 Lignin. According to Haase, the active principle of fox-glove resides in the soft resin. But Le Royer has /Announced in it a peculiar principle, which he has called digitalina, and which probably possesses alka- line properties. But the accuracy of this statement has been called in question by Brault and Poggiale. According to these chemistSj the substances extracted from the leaves of digitalis arc 1 Chlorophyllo 2 Resin 3 Fatty matter 4 Starch 5 Lignin 6 Gum 7 Tannin 8 Salts of lime and potash 9 A volatile oil 10 A fixed oil 1 1 Oxalate of potash.* 6. Tea. This substance, so much used in Great Britain as an article of food, is composed of the dried leaves of the thea bohea and thea viridis, plants which grow in the mountainous regions of China and in Japan. There are a great many varieties of tea; but it Is the opinion of botanists that they are all the produce of the two species above mentioned. The leaves of the thea bohea are larger than those of the viridis. The viridis is a hardy shrub, and even capable of bearing the summer temperature of the neighbourhood of London in the open air. The thea bohea is a more delicate plant, and requires the shelter of a green-house. Tea was introduced into Europe by the Dutch East India Com- pany, and was first brought into England about the year 1666, and was sold at the rate of sixty shillings per pound weight. For many years the price was so high as to confine its use to people of opu- lence. Of late years, since the China trade was thrown open, the price of tea has sunk considerably, and the consumption of it has increased enormously. In 1794 the consumption in Great Britain was 20,000,000 lbs. ; now it is not under 50,000,000 lbs. * Jour, dc rhannrtcic, xxi. I3.'{. LKAVES. 869 not in ether e resides in the luliar principle, possesses alka- has been called these chemists, are ■at Britain as an he thea bohea and regions of China of tea; but it is duce of the two I bohea are larger r shrub, and even neighbourhood of re delicate plant, East India Cora- le year 1666, and reight. For many to people of opu- thrown open, the umption of it has in Great Britain 000 lbs. The leaves are not fit to be pulled till the shrub has vegetuted for three years. When the tea leaves have been collected, they are exposed to the steam of boiling water. Every leaf is then rolled up by the hand, and they are put upon plates of copper and held over the fire till they b(!come dry and shrivelled. It is to this heat- ing process that tea owes its peculiar flavour. Tea leaves were analyzed by Frank, in 1798.* When distilled with water it loses all smell, and the product of the distillation ex- hibits traces of a volatile oil. The aqueous solution contains gum and tannin, which blackens the salts of iron. Bohea tea contains more tannin than green tea. From the residue, exhausted by water, caustic potash extracts albumen. Bohea tea contains Tannin Gum Albumen Lignin Green tea contains Tannin Gum Albumen Fibrin 40-6 6-3 6-4 44-8 98-1 Oudry has lately announced that he has discovered in tea a sali- tiable base, to which he has given the name of theina. The pro- perties of this substance, and its identity with caffein have been stated in a preceding Chapter of this volume. 6. Ledum latifolium. The leaves of this plant, which is a native of North America, are used as a substitute for tea, and are known by the name of James's tea. They were analyzed by M. Bacon, who extracted from them, 9 An animal substance 10 Gum 1 1 A potash salt 12 A lime salt 13 Sulphate of potash 1 4 Chloride of potassium" 15 Phosphate of lime 16 Silica.f /. Ilex paraguaiensis. This tree grows in different parts of South America, especially in Paraguay and the interior of Brazil. In the country it is said to be called yerva mate. It rises to the height of an orange tree. The leaves are opposite, shining, ob- long, and serrated. The flowers have the botanical characters of those of the holly, of which the tree is a species. These leaves are Water Lignin Green resl i Wax Tannin Gallic acid Bitter principle 8 Odorous principle ' m ;ii 'H * Berlin .lahrb. I7P8, p. 164. f Jour, de Pharrnacie, ix. 658. 860 LEAVES. M almost universally used in South America, under the name of Pa- raguay tea. The leaves are gathered from plants of only two or three years growth, when the diameter of the stem is about an inch. They are three or four inches long, and have a fine green colour. They are freed from their petioles or leaf stalks, which are hard and woody. When dried they become brittle. The leaves are dried in a kind of oven, heated by the plants previously deprived of their leaves. They are then packed in sacks, and are ready for use. An infusion of these leaves, in hot water, was used by the native Americans before the conquest of Brazil by the Portuguese. The conquerors learned the use of it, and it has become a fashionable and very common beverage all over South America. It produces a slight degree of intoxication, very agreeable. Tc the infusion it is customary to add sugar and a little lemon juice, tvrid hot water is poured repeatedly upon the same leaves. The people of South America ascribe the most admirable pro- {)erties to tliis tea. When used in moderation it acts as a stimu- ant ; but when taken in excess it occasions intoxication, and a kind of delirium tremens.* The dried leaves are yellowish-green, have a very slight herba- ceous smell and a bitterish astringent taste. Dr J. B. Trommsdorf is the only chemist who has had an opportunity of examining this tea, and the quantity in his possessi'r was too small for analysis. He detected a yellow colouring matter, two resins, and tannin.f As the infusion becomes muddy when mixed with tincture of iiutgalls, it may contain an alkaloid. But the small quantity in his posses- sion did not permit him to search for it. 8. lihewn palmatum, rhubarb. The leaves of this plant have been examined by Bouillon La Grange, who found them to contain a considerable quantity of binoxalate of potash and of malic acid.| 9. Isatis tinctoria, or woud. The leaves of this plant have been subjected to analysis by Chevreul. The expressed juice, separated by filtration from the green fecula, with which it was mixed, deposit- ed, on standing, a blue powder, which possessed the properties of indigo. When heated, white flocks separated, consisting no doubt of albumen. When distilled the liquid that came over yielded traces of a volatile oil, of ammonia and of sulphur. When distilled with sulphuric acid, the liquid that came over contained acetic acid and prussic acid. Evaporated to dryness, and digested in alcohol, it yielded to that liquid a quantity of matter described by him, by the name of green matter. It yielded also a yellow-coloured extractive, and the following salts : nitrate of potash, muriate oj ammonia, acetate of potash, muriate of potash, and pure acetic acid. The residue thus deprived of the substances soluble in alcohol consisted of gum, yellow extractive, supermalate of lime, sulphate oj * Jour, de Pharinacie, xviii. 137. t Ann. dcr Pharm. xvii. 89. J Ann. dc Chim. Ixvii. name of Po- or three years ,ch. They are XV. They are rd and woody. Iried in a kind if their leaves. se. d by the native tuguese. Tlie le a fashionable I. It produces ^ the infusion it vnd hot water is admirable pro- acts as a stimu- tion, and a kind py slight herba- 13. Trommsdorf ' examining this lall for analysis, ns, and tannin.f cture of uutgalls, ity in his posses- this plant have them to contain of malic acid.t plant have been i juice, separated IS mixed, deposit- the properties of isisting no doubt ime over yielded ' When distilled contained acetic and digested in tter described by a yellow-coloured otash, muriate oj 1 pure acetic acid. soluble in alcohol f lime, sulphate oj him. Uvii. ^1- LEAVES. 861 limey and a salt which Chevreul considered as citrate of lime-and- jtiapneaia. The green fecula being examined, was found to con- sist of green-coloured reain, wax^ indigo, gluten, and lignin. 'I'ho dry matter of tlie leaves, from wliich the juice had been expressed, yielded lignin, green resin, tvax, indigo, nitre, a red-coloured matter^ malaL of lime, and traces of some other salts.* The leaves of the indigo/era anil, examined by the same chemist, yielded the same products with the isatis, but the quantity of indigo obtained was much greater .f The leaves of the agathophyllum ravensara were found by Vau- quelin to contain an oil similar to the oil of cloves, gum, and car- bonate of lime.l 10. Menyanthus trifoliata. This plant was analyzed by Tromms- dorf. The fresh plant consists of 75 parts of moisture and 25 of solid matter. The expressed juice, when boiled, lets fall green flocks composed of 75 parts of vegetable albumen, and 25 of green resin. The liquid contains disengaged malic acid, acetate of potash, and a peculiar matter which is precipitated by tannin, but not coagu- lated by heat, and which is soluble in alcohol. It contains likewise a bitter extractive matter, a brown gum, and a quantity of inulin.§ 11. Centauria benedicta, or blessed thistle. The leaves of this plant, which is a native of Spain and the coasts of the Mediterra- nean, were formerly used in medicine, and the plant was called bene- dicta or blessed, from the supposed medicinal virtues which it pos- sessed. It was considered as a powerful alexipharmic, and capable of curing the plague and other fevers of the most malignant kind. When applied externally to cancers and carious bones it was sup- posed to heal them. It is needless to observe that these supposed virtues have not been found to hold good by modern practitioners, and that the plant is now seldom or never used in this country as a medicine. The plant is in greatest perfection when in flower. It should be cut at that time, quickly dried, and preserved in a dry airy place. It has a slight but unpleasant smell, and a very bitter taste. The leaves of this plant have been analyzed by Morin. The result of his analysis, and the properties of the bitter principle to which it owes its qualities, have been given in a preceding Chapter of this volume. 12. Guaco. The leaves of this plant, which is a native of Mexico, were recommended as a specific for the epidemic cholera, when raging some years ago in France. They were subjected to a chemical examination by M. Faure, an apothecary at Bordeaux, who obtaiiad from them the following substances : — 1 A fatty matter analagous to wax 2 Chlorophylle 3 Guacin Ann. dc Cliiin. Ixvii. 305. % Ibid. Ixxiii. 306. + Ibid. viii. 284. § Ibid. Ixxii. 191. (. ; y4\ ,i:!] ' 'mm ' -I im I h M - i 862 LEAVES. 4 Extractive and astringent mattor 5 I.ignin 6 Soino salts of soda, lime, and iron. The guacin has a yellow colour, a bitter taste, and no smell. It h brittle, melts easily when heated to 21*2*'. Very soluble in alcohol and other, and pretty soluble in boiling water, from which it preci- pitates as the liquid cools, being little soluble in cold water. Nitric acid dissolves it and gives it a deep yellow colour ; sulphuric acid dissolves it less completely, and acquires a deep brown colour; muriatic acid is an imperfect solvent, and does not alter its colour. It is destitute of alkaline characters. It is considered as the constituent in which the active principle of the guaco resides. But as the eil'ects ascribed to this plant as a speciiic for cholera have not been sufficiently confirmed, guacin has lost much of the interest that it had at first.* 13. Eupatorium aya-pana. The leaves of this syngenesious plant, which is a native of Brazil, but found also in the Isle of France, were much employed in that island as a remedy in the Indian cholera, and also in diseases of the breast and in iniigestions. They were subjected to a chemical examination by M. Waflart,t wlio found them to contain, 1 A fatty matter soluble in ether 2 An essential oil pretty abundant 3 A bitter principle easily separated from the extract by alcohol 4 Starch ") . r „ u - o ? a trace of each. 5 Sugar 3 14. Diosma crenata. This shrub is a native of the Cape of Good Hope. The infusion of its leaves was introduced some years aj^o into this country, as a remedy for the diseases of the urinary organs, particularly retention of urine. These leaves were subjected to sonio experiments by M. Cadet d^ Gassicourt, who extracted from 100 parts of them 1 An essential oil . . . 0*6G/^ 2 Gum 3 Aqueous alcoholic extract 4 Chlorophylle 5 Resin 21-17 5-170 1-100 2151 30'25Gt • Jour, de Pharmacic, xzil. 291. f Ibid. xv. 8. X Ibid. xiii. 106. smell. It U iblo in alcohol which it preci- wator. Nitric sulphuric acid brown colour; Iter its colour, isidored as the J resides. But r cholera have 1 of the interest nrenesious plant, Isle of France, in the Indian gestions. They . Waflart,t who the extract by le Cape of Good some years ago J urinary organs, mbjected to some racted from lOO 0-665^ 21-17 5-170 1-100 2-151 30-256t X Ibid, xiii- 106. MKUItA<;ROUS PLANTS. 863 CHAPTER X. ' () F II i; 11 11 A C K O U 8 PLANT S. Under this title I shall notice a few herbaceous plants, which have been examined altogether, leaves, stem, and branch(!3. Tlioy are not of much importance, though I think it better to notice them than 10 pass them over in silence. 1. Geranium zonale. This plant, which constitutes a common ornament of gardens, was subjected to some experiments by M. Braconnot.* The plant was pulled in the end of October, pounded in a mortar, and subjected to pressure. The expressed juice filtered rapidly, leaving on the filter green fecula, tannate of lime, chloro- plivllc, and lignin. The filtered juice was colourless, but assumed a hue blue colour like ink when mixed with persulphate of iron. Braconnot obtained from this juice the following constituents : 1 2 3 4 5 A large quantity of bimalate of lime A little bimalate of magnesia Much tartrate of lime Much phosphate of lime and of magnesia Tannin 6 Gallic acid 7 Apotheme 8 Tannate of lime 9 An extractive, insoluble in alcohol, having the savour of roasted meat 1 Malate of potash 1 1 Chloride of potassium. 2. Wormwood. This is the leaves, and likewise the stalks and flower-tops of the artemisia absynthium, a plant which grows wild in many parts of Britain. Wormwood has a strong smell, rather dis- agreeable, and an intensely bitter taste. Its smell is owing to a volatile oil which it contains. It contains, besides, a considerable portion of bitter principle. It was analyzed many years ago by Kunsmuller,t who obtained by water, from 12 parts of wormwood, the following products : — Resin 0-48 Muriate of potash . . . 0-12 Vegetable acid . . . 0-50 Ditto combined with potash . 2-14 3-24 The residue, after the action of the water, being burnt, left an ash. • Ann. de Chim. et de Phys. li. 328. f Ann. de Chim. vi. 3.5. ^ \t r: ■I >' t i li: ' 'I If; 864 HBRBACKOUS PLANTS. which, from 12 ounces of wormwood, contained the following sub- stances Muriate of potash Sulphate of potash Carbonate of lime Alumina Sulphate of lime . Silica Oxide of iron 3 1 69 5 5 4 3 grains Braconnot* subjected this plant to analysis and obtained Volatile oil Green resin .... Bitter resin .... Albumen .... Starch Azotized body, having little taste Bitter azotized body Lignin Nitre ..... Absynthate of potash Water 0-15 0-50 0-233 1-250 0-133 1-333 3-000 10-833 0-333 0-917 61-233 79-915 The ahsynthic acid may be precipitated from the infusion of worm- wood by the acetate of lead. It has a very sour taste, is incrystal- lizable and deliquescent. It does not precipitate solutions of nitrate of lead, mercury, or silver. When poured, drop by drop, into lime or barytes water it occasions a flocky precipitate. With ammonia it forms a salt which crystallizes in four-sided prisms, and which is insoluble in alcohol. 3. Gratiola officinalis. This plant was found by Vauquelin to contain, 1 . A brown gummy matter. 2. A resinous matter, differing from other resins in being soluble in hot water ; but much more soluble in alcohol than in water, and having a very bitter taste. It is in this substance that the purgative quality of the plant resides. 3. A small quantity of animal matter. 4. Common salt in consid- erable quantity, and another salt which is probably malate of potash. It contained likewise oxalate and phosphate of lime and oxide of iron, probably united to phosphoric acid.f 4. Conium maculatwnf or hemlock. This plant is called cicuta in the older pharmacopoeias. It is an umbellated plant, very common in Great Britain. Whether the xumov of Dioscorides be the same as our conium, cannot be ascertained ; nor can any light be thrown upon the poison, by which the Athenians were in the habit of put- ting their condemned to death. The symptoms of that poison are not only different from those produced by conium, but by every other vegetable poison with which we are acquainted.^ • Berzelius, Traits de Chimie, vi. 246. + Ann. de Chim. Ixxii. 191. X Pliny calls the poison used by the Athenians, cicuta; nor am I aware of tlie word conium occurring in any Latin classic. HERBACEOUS PLANTS. 865 'ollowing sub- is )tained 5 33 50 33 33 lOO 133 $33 )17 2^33 n5 fusion of worm- 3te, is incrystal- utions of nitrate drop, into lime With ammonia IS, and which is Vauquelin to matter, differing but much more bitter taste. It le plant resides, n salt in consid- aalate of potash, le and oxide of s called cicuta in it, very common ies be the same light be thrown e habit of put- that poison are but by every |ed.t Jchim. Ixxii. 191. Ir am I aware of tlie Conium. Cabbage. 1 27-3 23-4 35-2 28-9 1 1-5 0-5 i 3-1 2-9 ! 8 6-3 76-1 62-0 Hemlock is distinguished from other umbelliferous plants by its large and spotted stem, the dark shining colour of its lower leaves, and their disagreeable smell, if they be bruised when fresh — a smell which has been compared to the urine of a cat. For medicinal use, it should be gathered about the end of June, when the plant is in flower. The footstalks are to be thrown away, and the leaves with their branches carefully dried, and afterwards kept in boxes. Dr Christison has shown, that the common extract of conium of the shops contains little or none of the virtues of the plant. A chemical analysis of the expressed juice of this plant was made by Schrader, in 1812.* He found a striking similarity between its constituents and those of the expressed juice of the hrassica oleracea, or cabbage. He obtained from 1000 parts of each the fol- lowing constituents : — Extractive Gummy extract Resin Albumen Green fecula The active constituent of this plant is conicina, of which an account has been given in a preceding Chapter of this volume. 5. Chenopodium olidum. This plant contains uncombined am- monia, to which, in the opinion of MM. Chevalier and Lassaigne, it owes its peculiar smell. The substances extracted from the plant by these chemists, were the following : — Carbonate of ammonia Albumen Ozmazome An aromatic resin A bitter matter Nitrate of potash in considerable quantity Acetate and phosphate of potash Tartrate of potash. 100 parts of the plant yielded 5\ of potash f 6. Asparagus officinalis. The young shoots of this well-known plant are served upon the table, as an agreeable article of food. From the account which Dioscorides gives of aoTagayos, there is reason for considering it as the same with the asparagus of the moderns. This plant was formerly considered as a diuretic, and was employed in medicine. But it no longer finds a place in any of the British pharmacopoeias. M. Robiquet reduced asparagus to the state of a pulp, and sepa- *;iJ'^M ; ;; i'')' \i\ \m • Schweiggcr's Jour, v, 19. t Annals of Philosophy, xii. 231. 3k 866 HERBACEOUS PLANTS. rated its juice by expression. A feculous matter was separated from this juice by filtration. Boiling alcohol dissolved a portion of this fccula, and left matter which possessed the properties of gluten. As the alcohol cooled, a portion of wax precipitated. The alcohol, by evaporation, left a green acrid matter, intermediate in its pro- perties between resin and volatile oil. The filtered juice had the appearance of whey, and reddened the infusion of litmus. When heated it deposited flakes, which were considered by llobiquet as albumen. When left for a long time to evaporate in the open air, a quantity of asparagin and of saccharine matter, having the appearance of manna, separated in crystals. The juice was inspissated, and treated with alcohol. A portion dissolved ; the residue was dissolved in water. The alcoholic solution, when treated with sulphuric acid, and dis- tilled, yielded vinegar. When this solution was evaporated to dry- ness and burnt, the ashes consisted of potash, carbonate of lime, and phosphate of potash and of lime. Hence it was probable that the acetic acid was combined with potash and lime. The watery solution reddened vegetable blues. The infusion of nutgalls throws down a precipitate from this solution. The residue contains a peculiar extractive matter and a colouring matter ; and doubtless, also, asparagin and sugar. Such is the result of Robiquet's very ingenious and interesting analysis of this substance.* The subsequent facts discovered respecting asparagin, have been stated in a preceding part of this volume, while treating of aspartic acid and of asparagin. 7. Cochkaria officinalis, or scurvy grass. This plant, which abounds in the mountainous districts of Scotland, is occasionally employed in medicine as a diuretic, and as a cure fc the scurvy produced by living on salt food at sea. Its expressed juice was found by liraconnotf to contain Sweet matter, thrown down by tannin, and insoluble in cold alcohol . . . 48'33 Organic matter, insoluble in boiling alcohol, precipitated by tannin . . . 32'00 Lime, united to a vegetable acid . . 8'66 Potash, united to the same acid . , &'QQ Muriate and sulphate of potash, and loss 4'33 100 8. Mesemhryanthemum crystallinum. The juice of this plant is said to be always colder than the surrounding air. Dr John assures us, that on the 13th of September, when he was engaged in exam- ining it in Berlin, the thermometer in the shade stood at 54°^, but when plunged into the sap of this plant it sunk to 41°. He "found this sap composed of the following substances : — • Ann. de Chim. W. 152. f Jour, de Phys. Ixxxiv. 278. FLOWERS AND POLLEN. 8(57 yas separated d a portion of •ties of gluten. The alcohol, ate in its pro- i reddened the es, which were a long time to a of saccharine ed in crystals. ol. A portion c acid, and dis- iporated to dry- bonate of lime, IS probable that The infusion of 1. The residue ing matter ; and 1 and interesting irafjin, have been jating of aspartic his plant, which is occasionally fc- the scurvy iressed juice was and lol, 48-33 32-00 8-66 6-66 4-33 100 ce of this plant is Dr John assures eno-aged in exam- stood at 54°i, but o 41°. He found ^^ of its weight of water Lignin Extractive Gum Resin in minute quantity Albumen Green powder Nitrate of potash in considerable quantity Common salt Phosphate of lime Carbonate of lime.* 9. Sophora Japmiica. M. Fleurot of Dijon has examined the bark, the wood, the leaves, and the fruit of this plant, and found them to contain the following substances :t — 1 Cathartina 2 An odorous principle 3 Yellow colouring matter 4 Albumen f) Chlorophylle 6 Starch 7 Gum 8 Mucous sugar 9 Caoutchouc 10 Malate of lime 1 1 Other salts. CHAPTER XI. OF FLOWERS AND POLLEN. An account nf the colouring matters of the different flowers, so far as the subject has been examined, has been given in a preceding part of this volume, while treating of vegetable colouring matters. Our object in this place is to notice a few flowers which have been subjected to a chemical analysis, and to state the facts which have been ascertained respecting the pollen, or fructifying powder, shod by the antherse of flowers.. 1. Flowers of the carthamns tinctorius^ or safflower. In a preced- ing part of this volume, when treating of red colouring matters, a detailed account was given of safilower, and of the distinguishing colouring matter which it contains, known by the name of cartha- min. Our object here is merely to state the other constituents which exist in the petals of the carthamus, besides the two colour- ing matters noticed. Tlie following table exhibits the constituents I >l , ^ I ' M i I 9. Ixxxiv. 278. • Chemische Untersuchungcn, ii. 7. f Jour, de Pharmacie, xix. 510. m 868 FLOWERS AND POLLEN. of 1000 parts of carthamus, according to the four : — experiments of Du Moisture .... 62 Sand and small particles of the plant 34 Gluten ..... 55 Yellow colouring matter 268 Extractive 42 Resin 3 Wax ... 9 Red colouring matter Woody fibre Alumina and magnesia Red oxide of iron 5 496 5 2 Sand .... 12 Loss .... 7 1000 If we believe Marchais, a considerable portion of wliat was con- sidered by Dufour as woody fibre is in reality albumen. 2. Flowers of arnica montana. These flowers have been em- ployed in medicine, especially in Germany, where their virtues have been much celebrated. They have a yellow colour, a bitter and sharp taste, and a very weak aromatic smell. When macerated in water, the liquid acquires a brown colour and a bitter taste. It reddens the infusion of litmus, does not form a precipitate with glue, and does not alter the solution of tartar emetic. With sulphate of iron it strikes a deep green, which passes into black on drying. The mineral acids occasion brown precipitates, but the alkaline carbonates produce no change iu it.* When the flowers are macerated in alcohol, the liquid acquires a yellow colour. It reddens vegetable blues, strikes a green with sulphate of iron, and becomes milky when mixed with water. When this tincture is distilled, the alcohol which comes over has a bitter taste, but does not alter vegetable blues ; while the liquid which remains in the retort is »^ery acid, precipitates with water, and strikes a green with sulphate of iron. When evaporated to drjness, a bitter acid powder remains, seemingly of a peculiar nature.f When distilled, the flowers of the arnica yield a yellowish acid liquor, which strikes a black with sulphate of iron. This liquid is covered by a quantity of oil. When these flowers are burnt, the residual ashes contain potash, carbonate of potash, and muriate and sulphate of potash.J These flowers have been subjected to a chemical examination by MM. Chevallier and Lassaigne, who extracted from them the fol- lowing substances : — • Bouillon La Graiiirc, Ann. de Cliitn. Iv. 38. t Ibid. iv. .39. " X Jl>'d. FLOWERS AND POLLEN. 869 lents of Du- 2 4 5 8 2 3 9 5 )6 5 2 12 7 )00 ' what was con- len. have been ein- leir virtues have ir, a bitter and m macerated in bitter taste. It Ipitate with glue, With sulphate of )lack on drying, but the alkaline liquid acquires a es a green with xed with water. comes over has a \yhile the liquid itates with wator, m evaporated to y of a peculiar 1 a yellowish acid ,. This liquid is rs are burnt, tlie and muriate and al examination by rora them the fol- A resin having the odour of arnica A bitter nauseous substance resembling the emetic substance from the cytisus laburnum Gallic acid A yellow colouring matter Albumen Gum Muriate and phosphate of potash Traces of sulphates Carbonate of lime Silica.* 3. Artemisia santonica, or Tartarium, southernwood. The tops of the ripe flowers of this plant, and formerly the seeds, were used as anthelmintics, under the name of santonicum. The plant is said to be a native of Tartary and Persia. What is used in medicine comes partly from Aleppo and partly from India. It consists of small linear grains of a greenish yellow colour, mixed with about I of the weight of small tubercles considered as the summits of the ripe flower. It is called by the French barbotine, semeiitine, or cince semen, semencontra, that is contra vermes. According to the analysis of Trommsdorft'f it contains, Volatile oil ... . 0*8 Hard resin . . . . 11 '0 Bitter extract with malate of lime 21*0 Gum and extract insoluble in alcohol 36*0 Matter soluble in potash, very similar to gummy extract . . 20*0 Fibrin 12 100-8 The matter subjected to this analysis, had been dried at a pretty high temperature, by which it lost 10 per cent, of its weight. The active principle in the medicine seems to reside in the volatile oil, which may be obtained by distilling the santonicum with water. It has a pale yellow colour, a strong aromatic odour, and an acrid bitter taste, and is very volatile. It requires 1 000 times iis weight of water to dissolve it, but it dissolves with facility in alcohol and ether. Since the analysis of Trommsdorft", santonicum has been examined by Kohlar and Alms,+ who discovered about the same time a crys- talline matter which it contains, to which the name of santonin has been given. It was afterwards investigated more closely by Tromms- dorfF junior, who showed that it possessed acid properties. An ac- count of it has been already given in a preceding Chapter of this volume. 4. Tilia Europece, or lime tree. The flowers of this tree contain, according to PfafF,§ an odoriferous substance which may be distilled over along with water, but which cannot be procured under the form • Annals of Fliilosophy, xvi. 90. f N. Tr. iii. 1, 809. J Jour, do I'haini. xvii. 116. § Materia Med. iv. 92. Jil''i * i^n 870 FLOM'EttS AND POLLEN. k ! ( I V ' ■ ■.♦. i > i of a volatile oil. They contain also tannin, fermentible sugar, much gum and lignin. Brossat found, that when 100 lbs. of lime tree flowers were dis- tilled with water till 80 lbs. had passed over, the liquid thus obtained was muddy. When it was distilled anew, with 1 00 lbs. of the flowers till 40 lbs. of liquid passed over, a muddy liquid was obtained hav- ing an agreeable smell, on the surface of which some golden yellow drops swam. When preserved for five months in a cellar, it became mucilaginous like a decoction of lintseed, without losing its agree- able smell. When taken into the stomach, it produced intoxication. According to Roux,* alcohol extracts from the flowers of the lime tree chlorophylle and a yellow extractive matter. During the evaporation, the chlorophylle separates and leaves the yellow matter in the state of a brownish yellow solid which dissolves in water, communicating to it a yellow colour. Cold water extracts from the flowers, previously treated with alcohol, an additional quantity of the yellow matter, and a substance insoluble in alcohol, and preci- pitated by it in white flocks, which become brown when exposed to the air. The aqueous solution of this substance is precipitated olive by the salts of copper, greyish black by the proto-salts of iron, and yellow by corrosive sublimate, showing an essential difference from gum. If, after exhausting the flowers of the lime tree by means of alcohol and water, we boil them for some hours in water, we obtain a red- dish-brown decoction. If we filter this decoction, concentrate it by evaporation, and then pour into it alcohol, a great quantity of r»d colouring matter precipitates. When dry it is brownish red, weakly astringent, and is insoluble in alcohol and ether, but soluble in water, and is capable of precipitating the metallic salts. Acids destroy its colour, but alkalies produce little alteration in it. Ber- zelius considers it as a compound of gum and the apotheme of tannin. 5. Calendula officinalis, or marygold. The flowers of this well known plant, so common in our gardens, wer»i formerly used in medicine ; but they have been struck out of all the British pharma- copoeias. They contain, according to the analysis of Geiger,t Greenish yellow soft resin 3-44 Bitter extractive 19-13 Gum .... 1-50 Starch .... 1-25 Calendulin 3-50 Albumen 0-62 Malic acid with bitter extractive 6-84 Malate of potash • 5-45 Malate of lime « 1-47 Chloride of potassium • 0-66 Lignin .... • 62-50 106-36 * Jour, de Pharm. xi. 507. t Diss, de Calendula Officinali. Heidelberg, 18 1 9, FLOWERS AND POLLEN. 871 Qtible sugar, ers were dis- thus obtained of tlie flowers obtained hav- goldcn yellow liar, it became ting its agree- d intoxication, flowers of the . During the yellow matter dves in water, tracts from the nal quantity of ihol, and preci- hen exposed to is precipitated ,to-salts of iron, Butial diff'erence means of alcohol «re obtain a red- ;oncentrate it by quantity of r<^d nish red, weakly , but soluble in ic salts. Acids tion in it. Ber- )tbeme of tannin. vers of this well formerly used in I British pbarma- 5 of Geiger,t 3-44 9-13 1-50 1-25 3-50 0-62 G-84 5-45 1-47 0-66 62^ 06-36 Heidelberg,lfil9' The ccdendulin of Geiger appears to be a species of vegetable mucilage. Its properties, and the method of obtaining it, have been described in a preceding Chapter of this volume. The anthers; of most vegetables, at the time that the flower is in perfection, are covered with a considerable quantity of a powdery matter, usually of a yellow colour, which, falling unon the pistils, is supposed to impregnate them. Tills matter is known by the name of pollen. In some plants, especially those in which the male and female flowers arc separate, the quantity of it is so great, that it may easily be collected. The first person who examined this powder was Dr Lewis ; but in his time chemistry had not made sufficient progress to enable him to make a complete analysis. He found that alcohol in which it is macerated, acquires a bright yellow colour, and that water takes a duller yellow, while the undissolved portion, is of a yellowish-white colour. The colour of these infusions is heightened by alkalies, and turned red by acids. When alkalies are dropt into the reddened solu- tion, a deep yellow colour is restored.* Fourcroy and Vauquelin have published a detailed analysis of the pollen of the phoenix dactili/era, or date tree, which may be consi- dered as furnishing a pretty correct view of the properties of this class of vegetable substances. At least it is probable that the pollen of different vegetables does not differ nearly so much from each other as the other parts of plants. The pollen of this tree is so abundant, that at the season of fructi- fication, it surrounds the plants like thick dust. The specimen examined was brought from Egypt by Delisle. Its colour was sulphur-yellow, its taste was sourish and unpleasant, it reddened the infusion of litn:us, and communicated to water a yellow colour, and a sensible degree of acidity. The watery infusion was precipitated by lime water and ammonia, by alcohol, and by some metallic salts. When pollen was washed in cold water, that liquid acquired a reddish-brown colour, a sourish taste and smell, not unlike that of beer. When evaporated, the liquid left a reddish-brown matter, which had the consistence and odour of molasses ; its taste was acid, but disagreeable. Cold alcohol produced no effect upon this matter, but by the assistance of heat it dissolved a portion of it, and assumed a dark colour. The residue had more consioience and was less coloured. It dissolved with facility in water, allowing at the same time a greyish bulky matter to separate. Thus the matter taken up by the watery infusion from pollen has been divided into three portions. The alcoholic solution being concentrated by evaporation to the consistence of an extract, had a red colour, the odour of baked apples, and a taste strongly acid, but disagreeable. It presented all the characters of malic ccid. The grey matter, which refused to dissolve in water, possess>'d the properties of phosphate of linfie. The aqueous solution was ascertained to consist chiefly of phos- * Neumann's Chem. p. 281. !. .•! 111: ■■(( I I •''' ( ' I M 872 FLOWKIIS AM) POLLEN. i phatc of magnesia, malic acid, and an animal matter, which formed a copious precipitate with the infusion of nutgalls. The pollen, thus deprived of its soluhle matter, being exposed on filtering paper to the open air for a week, instead of drying assumed the form of a paste, and ran rapidly to putrefaction, emitting an odo'ir similar to that of old cheese. When dried, this matter became semitransparent, and of a consistence resembling that of glue. Be- fore being dried it mixed readily with water, and exhibited the characters of soap. The fixed alkalies showed the presence of ammonia in it. When distilled there came over a watery liquid, which gradually became coloured as the distillation advanced : some time after there came over a red coloured oil and carbonate of ammonia, partly in crystals, and partly in solution. The liquid also contained a portion of the oil in the state of a soap. The charcoal left was voluminous, and difficult of incineration. When burnt it left a considerable portion of phosphate of lime. This substance is the pollen in of John. The pollen is partly soluble in muriatic acid. The nitric acid reduces it to a paste, azotic gas is disengaged, and afterwards, on the application of heat, nitrous gas and carbonic acid. A yellowish oil separated and swam upon the surface, and alkalies separated earthy phosphates and oxalates. When the liquid was evaporated to dryness, it left a yellowish-red matter, extremely bitter, tenacious and adhesive, and perfectly soluble in water. This matter, from the description of it, must have been a species of artificial tannin. Thus it appears, that by the action of nitric acid, the portion of the pollen which is insoluble in water is converted into oil and artificial tannin. The oily matter became solid on cooling, and possessed almost exactly the properties of tallow treated with nitric acid. Strong alkaline leys dissolve the pollen, and assume with it the properties of soap, while ammonia is disengaged. When the pollen, mixed with water, is set aside to ferment, it dis- engages the odour of new cheese, and assumes the form of a tena- cious mass. Its taste is extremely sharp ; it contains abundance of ammonia, partly united to oil, and partly to malic acid. From all these phenomena, there is reason to believe that the insoluble part of the pollen approaches vegetable gluten in its properties; or rather, that it k. intermediate between gluten and albumen. Such are the properties and constituents of the pollen of the date tree, as far as they have been ascertained by Fourcroy and Vau- quelin.* Professor Link has examined the pollen of the hazel nut. It differs a good deal from that of the date tree just described. He found in it tannin in great abundance, a resin, a good deal of gluten, and a little fibrin.t The pollen of the tulip, which has been care- fully analyzed by Grotthus, is also very different from that of the date tree. He could neither detect in it phosphorus nor poUenin. From 26 grains of it he extracted • Ann de Mus. tl'Hist. Nat. i. 417. f A^nn- de Chim. Ixii. 292. FLOWERS ANU POLLEN. 873 lich formed exposed on ,ng assumed emitting an itter became f glue. Be- sliibited tlie presence of atery liquid, inced: some carbonate of he liquid also The charcoal sn burnt it left bstance is the he nitric acid ifterwards, on A yellowish Jies separated as evaporateJ itter, tenacious 3 matter, from rtificial tannin. » portion of the il and artificial and possessed rtitric acid, me with it the ferment, it dis- form of a tena- is abundance oi icid. From all e insoluble part :rties; or rather, a ^Uen of the date rcroy and Vau- p hazel nut. It described. He d deal of gluten, 1 has been care- frora that of the frus nor poUenin. 3him. Ixii. 29-2. Vegetable albumen Malate of lime with trace of roalate of magnesia Malic acid Malate of ammonia 1 Colouring matter > . . . . , Saltpetre ? j t 3. The pollen of the pinns sylvestria or Scotch fir the analysis of John, is composed of Cerin ....... v^ll ........ Brownish-yellow resin Malates of potash, lime, and magnesia, with some Sugar, with a trace of extractive Albumen Pollenin ....... Sulphate 1 Muriate [• of potash Phosphate j Phosphate of lime Oxide of iron Malate of ammonia Sulphur ? . 20-25 3-50 1-00 1-25 26-00* , according to 2-00 trace 3-75 gum 6-00 5-00 4-00 77-25 3-00 trace trace 100-00 4. The constituents of the pollen of the ■pirms abies he found as follows : — Cerin 2-25 Oil ...,....„ trace Brownish-yellow resin 4*00 Malates ol potash, lime, and magnesia, with some gum 6-00 Sugar ........ 4-50 Extractive ........ trace Albumer 4-00 Pollenin 75-25 Sulphur ? trace Malate of ammonia Sulpnate 1 Muriate > of potash \ _ „,^« Phosphate j Phosphate of lime Oxide of iron 100-00 5. The pollen oi jtiglans regia, cannabis sativa, zey mays, and of tulips, was likewise examined by Dr John, and found to contain nearly the same ingredients, though not in quite the same propor- tions.f 'Schwciggcr's Jour. xi. 281. ,t Chcmische Untersuchungen, iv. 27. !;^'!i i.i m I ;''i ; 'i 874 FLOV, ERS AND FOLLEN. 47 25-96 18-32 6. The pollen of the tnlipa stiavcolens, or common tulip, was examined by John.* He found in it tiio following constituents : — 1 Yellow coloured pollenin 2 Much uncrystfdlizuble sugar 3 A little cerin, tinged blue 4 A violet blue pigment soluble in water and alcohol 5 Volatile matter G Supermalates of potash, lime, and magnesia 7 Traces of other salts with the same bases 8 Albumen. 7. Typha latijhlia. M. Braconnot examined in 1829, the pollen of the typha latifolia, which it is well known is abundant, and is sometimes mixed with lycopodium, though it does not burn quite so rapidly. He obtained : — f 1 Water 2 Pollenin 3 Yellow colouring mattter 4 Sugar 6 Matter slightly azotized G Gum ... 7 Fat formed of stearin and olein 8 Starcli .... 9 Phosjjhate of magnesia and lime 10 Phosphate of potash J 1 1 Malate of potash 12 Silica .... 13 Oxide of iron 100-32 The properties of the pollenin of the typha, were different from those of the phenix dactrjUfcra. The grains of typha pollen con- tained starch, which seemed to occupy the interior portion of each particle, and cannot be removed by boiling water nor acetic acid. But boiling dilute solution of tartaric acid dissolves it, and so does muriatic acid. The portion of the pollen insoluble in water, depriv- ed by caustic potash of the starch, the fatty matter, and a portion of the colouring j)rinciple may be considered as the pollenin. It is azotized, but much less so than albumen; insoluble in caustic alkalies and in boiling muriatic acidj but soluble in concentrated sulphuric acid; from which it is precipitated by water. It dissolves also with difficulty in concentrated boiling acetic acid, and water throws it down in white curdy flocks. When in this state of divi- sion it is soluble in ammonia and in caustic potash, from which it may be separated by acids in the state of a white coagulum. If we boil the potash solution of this pollenin its nature is altered, for it cannot be thrown down by acids ; but it is precipitated from the saturated solution by alcohol and by the infusion of nutgalls. • Schwcigger's Journal, xii. 244. f Ann. de Chim. et de Phys. xlii. 91. X Containing some muriate and a trace of sulphate. 3-60 2-08 1-28 1-28 0-40 0-40 trace on tulip, was nstituents :— and alcohol », ncsia ,se9 ^29, the pollen )unritled. (lay-Lusaac has observed that seeds, almost without exception, contain axote. For when distilled they yield aniiuonia; or at least a product from which annnonia may be evolved by means of (luick- lime.* It is scarcely necessary to remark, that only a comparatively small number of seeds and fruits have been hitherto subjected tu chemical analysis. 1. jyheat, the triticum hyoerimm, astivum, and other species, has been cultivated from time imiuemorial in I'lurope and the northern parts of Africa, and the seeds of it employed as one of the most nnportant articles of food. Indeed wheat Hour is the only substance known from which good loaf bread can be made. The seeds, when ripe, are ground to a fme powder, and by passing this powder through cloth sieves, of various degrees of lineness, it is separated into distinct portions. The fine flojir constitutes the greatest por- tion ; and the bran^ which consists of the outer coat of the seed, and which is the coarsest of all, consfitutes the next greatest por- tion. The common wheat of this country, which is the triticum hyher- nnm, was analyzed by Vauquelin,f who obtained tlie following con- stituents from different varieties of it. French wheat. Odciaa hard wheat. OdOMa suft wheat. Ditto. Ditto. Flour of I'arii bakeri. Ditto of f|(>odi|Uiu llty, uaed ill pulilic catabiiih. menti. Ditto iiil'erior i kind, j Starch Ciluten . Sugar Gum Bran Water . 71-49 10-96 4-72 3-32 10 36'3 14-33 8-48 4-90 2-30 12-00 62-00 12-00 7-.^6 3-80 1-20 10 7(f84 1210 4-90 4-60 8-00 72-00 7*30 3-42 3-30 12 72-8 10-2 4-2 2-8 10-0 71-2 10-3 4-8 3-6 8 67-78! 9-02 4-80 4-60 2-00 12-00 1 IOO20| 100-49 i 98-73 1 98-30 100-44 100-02 100-0 97-9 It appears from the preceding analyses that the Odessa wheat con- tains a much greater quantity of sugar than French wheat. The gluten of the preceding table is, in fact, a mixture of gluten and albumen. The gum differs from coumion gum. It has a brown colour and contains azote. When treated with nitric acid it does not form mucic acid, but oxalic acid and the bitter principle of Welter. M. Zcnneck, in 1823, analyzed the seeds of the triticum dicoccon, employed in Germany as food for birds.| From 100 parts of these seeds, well dried, he obtained, * Jour, do Pharinacic, xx. 29.^ f Ibid. viii. 333. % Sfhwciggcr's Jarhbuch, ix. 323. SKKDS ANn FRUITS. 877 clicmistd, re- i l\io «ouda of DUt oxcci»tion, ia ; or at Iwvst cans of t\uick- comparativcly o Bulijccted to ler species, baa id the northern ne of the most • only suhstanco Hie seeds, when i,g this powder , it is separated ;he greatest por- oat of the seed, xt greatest por- 10 triticum hyber- lie following con- I Ditto of L.„nf "'""'''"^ ^'"" ari. i„ puiillc ki„a. »*•"• Ifitablith-: menu. 72-8 0-2 42 10-0 71 -2 10-3 4-8 3-G 8 67'7Si 9-02 1 4'ao 4-60 2-00 12-00 ; OOO_L97-9jlOO;20| Odessa wheat con- cnch wheat. Tlie ure of gluten and It has a brown nitric acid it does bitter principle ot ic triticum dicoccon, 100 parts of these id. viii. 3a3. (Jluten i:j-oo Husk ID'HH Starch M'H I Bitter matter, soluble in other . 2-!)7 Sweet extractive matter* 2-M Mucilage and albuuicn '2'97 100-00 The finest flour from triticum upclta, w.is analyzed by Vogel,t in 18 IG, and found by him to contain Starch 74 (Muten 22 Sugar 5*5 Albumen ..... 0*5 102 The flour from the triticum monococcum was likewise analyzed by Zenneck.f Ho obtained Resin, extract, sugar, and gum II '35 Starch ()4-84 Lignin ..... 7*48 Gluten 14'96 Albumen . . . . 1*37 100-00 2. Rye is the seed of the secale cereale, a plant cultivated in the northern parts of Europe, in considerable quantity, as an article of food. Bread mado i)f it is much denser than wheaten bread, and lias a brownish rolour, and a peculiar sweetish taste, which to most persons is rathor acreeable. We are indebted to Einhof for an elaborate analysis of rye-meal. He published the result of his ex- periments in the summer of 1805.§ A determinate portion of rye-meal was formed into a paste, and washed in pure water till that liquid ceased to acquire any colour, or take up any thing. The liquid, after filtration, had a yellowish colour, an insipid taste, and a smell like tiiat • '" new whey. It slightly reddened litmus paper, and was rendered muddy by car- bonate of ])otash, sulphate of silver, and infusion of galls. When raised to the boiling temperature, it became mudi.y, and a number of white flakes separated. These, when collected and edulcorated, had the appearanct- of curd. Tliey dissolved in alkaline leys, were in- soluble in alcohol, and possessed the properties of vegetable albumen. When the liquid was concentrated by evaporation, it deposited a small additional portion of albumen. This being separated, the liquid was evaporated to the consistence of honey, and digested in alcohol repeatedly till nothing more was taken up. The residue was greyish-white and insipid : water dissolved it slowly, and the * Soluble in water and alcohol. f Schweigger's Joiirn. x^iii. >f*l. t Ibid, xliii. 487. ,. § Geblen's Jour. v. 131. ill M 1 X- I f Z » 1^ i' I it ! ' i 1 lit 'll 1 \ I Hi If • H \\\4 "'I J"H|PW.!l(i.ii!H;ip||«?^^?W^ 878 SEEDS AND FRUITS. solution, being evaporated, deposited more flakes of albumen. The residue had the appearance of a solution of gum arable, and when evaporated to dryness, left behind it a portion of gummy matter. The alcoholic solution became muddy when mixed with water. The alcohol being drawn off by distillation, there remained in the retort an aqueous solution, of a wine-yellow colour with large brown- ish flakes swimming in it. These flakes, when collected, were found to possess the properties of gluten. They formed a glutinous mass with cold water, thp bulk of which contracted when the water was made to boil. Boiling alcohol dissolved it ; but ether took up only the colouring matter. Alkalies dissolved it, and acids threw it down again from its solution. The watery solution, thus freed from the gluten, being evapor- ated, left an extract of a wine-yellow colour. By repeated diges- tions in alcohol, dilutions with water, and evaporations, it was freed from a portion of gluten, which still adhered to it. Its taste was then sweet, but harsh ; its colour wine-yellow ; and it was soluble in water, alcohol, and ether. It was considered as the saccharine matter of rye. The rye-meal, thus freed from the matters soluble in water, was mixed with a great quantity of water, and by repeatedly agitating the liquid, and decanting it off after st' nding some time, it was separated into two portions ; namely, a greyish-coloured substance, which, being lightest, did not so soon subside, and a white powder which possessed the properties of starch. The grey-coloured sub- stance, by repeated digestions in alcohol and water, was separated into three portions ; namely, gluten, starch, and the coats of the rye- seeds. Such are the constituents of rye-meal, according to Einhof. The following are the proportions of these different substances, detected by this chemist, in the best rye-seeds and rye-meal. 3840 parts of good rye-seeds were composed of Husk . . . . . 930 Moisture . . . . 390 Pure meal .... 2520 100 parts of good rye-meal contained Albumen Gluten, not dried . Mucilage Starch Saccharine matter . Husk Loss 3840 3-27 9-48 11-09 61-09 3-27 6-38 5-42 100-00 But the proportion of these substances must vary extremely ac- cording to the soil, the climate, and the age of the rye. The gluten of rye differs in several particulars from that of wheat. It is less I autnen. The lie, and when my matter. [ with water, nained in the I large brown- id, were found i a glutinous hen the water ether took up J acids threw being evapor- speated diges- ts, it was freed Its taste was was soluble in the saccharine ; in water, was tedly agitating tie time, it was ired substance, a white powder y-coloured sub- was separated oats of the rye- ding to Einhof. snt substances, e-meal. 3840 [30 |90 f20 27 |48 09 09 27 38 142 [oo extremely ac- re. The gluten leat. It is less SEEDS AND FUUITS. 879 tenacious and more soluble. When it was allowed to ferment, Einhof perceived a strong smell of nitric acid, which is peculiar to this species of gluten. The starch of rye bears a striking resem- blance to that of wheat. Like this last, it does not form a colour- less solution with boiling ..ater, and always precipitates at last, when the solution is left a sufficient time at rest. Einhof did not '^xaraine the ashes of rye ; but from the experi- ments of Schrader, we know that the same quantity, analyzed by Einhof, namely, 3840, yielded the following fixed substances.* Silica 3'90 Carbonate of lime Carbonate of magnesia Alumina . Oxide of manganese . Oxide of iron . 3-35 3-55 0-35 0-80 0-22 12-17 It is well known that rye is liable to a disease which alters the appearance of the grain, and gives it new properties. In this state it is distinguished in France by the name of seigle ergote, and we give to the seeds of rye altered by this disease, the name of ergot of rye, or in Latin secale cornutum. The ergot is a kind of spur which issues from the grain of rye. It is elongated and curved, marked with three blunt angles and longitudinal lines. Its colour is violet of different shades. Internally it has a dirty-white colour. When collected in quantities, it emits, while fresh, a disagreeable smell. Its taste is slightly biting and nauseous. Its length is about an inch or an inch and a half, and its thickness about a quarter of an inch. According to DecandoUe, it is a species of fungus to which he has given the name of sclerotium clavis. Others consider it as a morbid alteration of the ovarium of the rye, caused by the punc- ture of an insect of the genus musca, and which deposits a blackish liquid. When taken into the stomach in any quantity, it produces tetanus, gangrene, and death. In small doses it stimulates the uterus, and is very useful in cases of difficult parturition. According to the analysis of Vauquelin,t it contains a soft yel- lowish red resin, having an acrid taste, and leaving in the mouth an impression similar to that of fish oil ; a sweet soft oil, which may be obtained either by expression or by boiling the ergot in water after it has been exhausted by alcohol, the oil separates and swims on tlie surface of the decoction ; a violet colouring matter, soluble in water, but insoluble in alcohol, which gives a reddish-yellow colour to silk or wool impregnated with alumina ; a great quantity of an azolized substance, which is insoluble in alcohol, soluble in water, and precipitated by infusion of nutgalls, which putrefies readily, giving out the smell of putrid fish. Ergot contains neither starch nor sugar, but an uncombined acid, which may be the phosphoric. * Gehlen's Jour. iii. 525. f Ann. de Chim. et de Pliys. iii. 337. \ i'S i*il., .1^: U^ % m l\ ifl IH m il : It.' I n Mi 880 SEEDS AND FRUITS. Pettenkofer* found that when ergot was treated with weak .alco- hol it furnishes a brownish-red tincture, which deposits, when the greater part of the alcohol is distilled off, 18*75 per cent, of a soft green wax, which melts at 212o, and when burnt leaves a charcoal containing phosphoric acid. The liquid freed from the wax gives a brown, transparent, bitter, and acidulous extract, which continues soft though heated to 176°, and absorbs moisture rapidly in the air. Pettenkofer, after some days, observed in this extract some cubic crystals which he considered to be phosphate of morphina, but this conjecture has not been proved. 3. Oals are the seeds of the avena sativa, a plant cultivated in considerable quantities as an article of food. The husk is uncom- monly thick, and constitutes a considerable portion of the corn. The proportion of starch is likewise considerable, though it is diffi- cult to free it from another substance with which it is united. Vogel found that 100 parts of oats consisted of Meal 66 Husk ....:, 34 100 dried meal yielded Fat yellowish-green oil 2 Bitter extract and sugar . 8-25 Gum ..... 2-5 A grey substance like albumen . 4-3 Starch 59-0 Moisture and loss 23-95 100-00 4. Barley is the seed of the hordeum vulgare, a plant too well known to require any description. Great crops of it are reared annually, partly as an article of food, and partly as a material from which malt liquors and ardent spirits are drawn. This species of corn has been examined with considerable attention by chemists, partly in order to form correct conceptions, if possible, of the na- ture of the process of fermentation, and partly to ascertain the con- stituents of barley. Fourcroy and Vauquelin published several in- genious remarks and experiments on it in 1806,t and Einhof pub- lished a still more elaborate analysis about the commencement of the same year ; having examined this grain in different stages of its growth, and after it was fully ripe.J When unripe barley-corns are triturated with water, the liquid acquires a milky colour. If this process be continued, adding fresh portions of water as long as the liquid passes off muddy, there remains only a green husky matter. When this matter is macerated a sufficient time in cold water, it acquires a greenish-ffrey colour, and when dry has the appearance of vegetable fibre. The water in • Repert. iii. 65. f Ann. de Mus. (i'Hist. Nat. No. xxxvii. p. 5. X Gehlen's Jour. vi. 62. • £EEDS AND FRUITS. 881 ,h weak.alco- ts, when the ent. of a soft es a charcoal the wax gives lich continues dly in the air. ,ct some cubic )hina, but this t cultivated in lusk is uncom- 1 of the corn, ough it is diffi- s united. 66 34 100 (•25 2-5 4-3 t^ }-95 0-00 a plant too well of it are reared 1 a material from This species of ion by chemists, isible, of the na- scertain the con- Tished several in- land Einhof pub- ommencement of Irent stages of its water, the liquid Led, adding fresh [off muddy, there Itter is macerated Inish-grey colour, The water in Jo. xxxvii. p. 5- which it was macerated, when boiled, deposits a few flakes of albumen, and when evaporated to dryness leaves a small portion of extractive. The water with which the barley was triturated is at first milky, and gradually deposits a white powder; yet it does not become transparent, though allowed to stand a considerable time. When filtered, it passes through transparent, while a slimy substance of a greenish-grey colour remains upon the filter. This substance pos- sesses the properties of gluten. When the solution, now transpa- rent and of a yellowish colour, is boiled, it deposits flakes of albu- men. It reddens litmus paper, and is strongly precipitated by lime-water, nitrate of lead, and sulphate of iron, indicating the pre- sence of phosphoric salts. The liquid being evaporated to the consistence of a syrup, and the residue treated with alcohol, the solution diluted with water, and the alcohol distilled off, to separate some gluten which still remained, a syrupy matter was obtained, having a sweet taste, which was considered as the saccharine matter of the barley. A por- tion refused to dissolve in alcohol. This portion was considered as erJi:. '*'"^. T •- lite powder which precipitated from the water in which the . ^j had been originally triturated possessed the properties of starch. Such are the constituents of unripe barley, according to the ex- periments of Einhof. The following are the proportions of each which he obtained from 2880 parts of unripe barley : — * Green husk, &c. Albumen, with phosphate of lime Gluten . . . . . Saccharine matter Extractive . . . Starch .... Volatile matter Loss . . . . . 478 13 51 160 76 420 1500 182 2880 When ripe birley is steeped in water a sufficient time, and then cautiously kneaded between the fingers in a cloth, every part of the grain is washed away except the husk, which by this process may be dried and weighed. When barley meal, previously made into a paste, is treated in the same way, a brownish residuum remains, consisting chiefly of the husk, though it contains also portions of starch and gluten which cannot well be separated. The water in which the meal has been washed gradually deposits a white powder, but does not become transparent though left at rest. It runs very soon into acidity. Indeed, if we believe Fourcroy and Vauquelin, barley often con- 'ft:l 1! ■!' I- m li : h i>. im ;!■ ! • Gehlen's Jour. y\. 83. 3l 882 SEEDS AND FRUITS. tains an acid ; the water in which it has been macerated reddening the infusion of litmus : this acid is the acetic. The colour of this water is reddish-brown. It holds in solution a considerable portion of matter, which, according to Fourcroy and Vauquelin, consists ■iiefly of gluten, but which Einhof found to be of a more compli- cated nature, consisting of albumen, or rather gluten, mucilage, and saccharine matter. It contains :;. solution likewise a notable por- tion of phosphate of lime. When barley meal is macerated a sufficient time »•: a'cohol, that liquid acquires a yellow colour, and becomes muddy and more odor- ous, and by evaporation leaves an oily matter of a yellow colour and an acrid taste, having the consistence of butter. This oil burns like a fat oil, and C •'•ms soap with alkalies. It is but imperfectly soluble in alcohol.* This oil escaped the observation of Einhof. I obtained it by a process similar to that afterwards described by Fourcroy and Vauquelin ; but its colour was asparagus green, and it did not burn with the same readiness as an oil. It has very much the appearance of olive oil coagulated, but its consistence is less, and its colour is darker. To this oil the peculiar flavour of spirits from raw grain is ascribed at present. If this opinion be well founded, the oil must be dissipated or destroyed by the process of malting. The following are the proportions of the constituents obtained by Einhof from 3840 parts of barley-corns: — Volatile matter .... 430 Husk 720 Meal 2C90 3840 From the same quantity of barley-meal he obtained Volatile matter .... 360 Albumen 44 Saccharine matter . . . 200 Mucilage 176 Phosphate of lime, with some albumen 9 Gluten 135 Husk, with some gluten and starch 260 Starch, not quite free from gluten 2o80 Loss ..... 76 3840 Besides these substances, Fourcroy and Vauquelin ascertained the presence of phosphates of lime and magnesia, and of silica and iron; and I found in it phosphate of potash and nitrate of soda. The presence of phosphate of potash was ascertained likewise by Saus- sure, junior. 5. Rice, the seeds of the orysa saliva, have been analyzed by Braconnot. He found in this grain the following constituents :— " Fourcroy and Vauquelin, Ann. de Mus. d'Hist. Nat. No.xxxvii. 8. , reddening [our of this able portion lin, consists lore compli- lucilage, and notable por- a'cohol, that d more odor- )W colour and rhis oil burns it imperfectly on of Einhof. 5 described by rus green, and 'has verjr much sistence is less, ivour of spirits )pinion be well y the process of Ltuents obtained 430 720 :90 SEEDS AND FRUITS. 883 Water • Carolina nice. 5-00 Piedmont Rice. 7-00 Starch * • 85-07 . 83-80 Parenchyma Gluten • • • • 4-80 3-60 4-80 3-60 Uncrystallizable sugar Gummy matter approaching Oil • starch • 0-29 0-71 0-13 0-05 0-10 0-25 Phosphate of lime • • 0-13 0-40 99-73 100-00 Besides traces of muriate of potash, phosphate of potash, acetic acid, sulphur and lime and potash united to a vegetable alkali.* Vauquelin was unable to detect any saccharine matter in rice. He found in it a little phosphate of lime and gum.f 6. Mais is the seeds of the zea mais, or Indian corn, a native of America, but now cultivated in Italy and other southern countries of Europe. It was cultivated and much used in Peru, before the con- quest of that country by the Spaniards. They even knew the method of fermenting it, and of producing from it an intoxicating liquid, to which they gave the name of chicea. Mais was first analyzed by Professor Gorham.t He obtained Water Starch Zein Albumen Gum Sugar Fresh. 9 Dried. 77 84-599 3 3-296 2-5 • 2-747 1-75 . 1-922 1-45 . 1-593 made M. Bizio§ obtained Starch Zein Extractive Zimome 94-7 94-157 a subsequent analysis of it in '"23, and 3840 . ^ . In ascertained the I of silica and iron; Ite of soda. The Ilikewiseby Saus- Ibeen analyzed by constituents :— [t. No.xxxvii. 8. Gum Sugar Fat oil . Hordein Salts, acetic acid and loss 80-920 5-758 1-092 0-945 2-283 0-895 0-323 7-710 0-074 100-000 The extractive matter possessed peculiar properties. While I warm, it could be drawn into threads like turpentine, and could be 1 kneaded between the fingers without adhering to them. After * Ann. de Chim. et de Phys. iv. 370. t Journal of Science, xi. 205. t Annals of Philosophy, xii, 151. § Schweigger's Jour, xxxvii. 377. >: 1 U: ,(■ 1 1 ■-•.•■ite! ^^! Wi !' W: ft' ■ ' ■ 'I m:. m 1 4 1 ill R84 SRRDH AND PUD ITS. coolingt it boonniu hard mu\ liritths and could lio Hnpiiratnd into thin trauHlucont (;iinia)iion-colourod truMX'H. It had a Hwortinli-hittiM' tastu and tho HnicU of honey. It dlMHolvod roa thu gluten wliid; niaiHcontainH. Tho mode of proc\u'ing it, and ita propcrtioH, have boon given in a preceding (Miapter of this volume. M. Pallas ha» sliown, that the Htem of mais, before flowering, contains no sugar ; at the titno of flowering, it contains a trace of crystullizabh^ sugar. Twenty or twejity-tlvo days after flow(5ring, it contains I per cent, of cryatalllzable sugar. When the grain Ih ripo ami only rctpurea to bo dri(»d, tho stem, being still greeji, (U)n- tains 2 pur cent of sugar and 4 per cent, of nu)lasaes, luiving an ox- cooiiwigly agrooable taste.* 7. Pens. The aeods of tiwpisum sntivmn conatituto a very (iomnion and nutritive article of food. They have been examined in tlifl'cr- ent states by l'liidiof,f who has devoted hia chief attention to this pocvdiar branch of chemical investigation. Hy treating tho green plant nearly in a similar manner with bar- ley, ho obtained from 3840 parts the following constituents: — Volatile nuitter . . . 3000 Starch .... 53 Vegetabl(» fdire . . . 400 Glutent .... 70 Albumen .... 35 Phosphate of lime ... 4 Saccharine matter . . . 116 Extractive .... 25 Loss 77 3840 The green pod or husk of tho tree, by a similar treatment, yield- ed, from 3840 parts,§ Volatile matter . . . 3120 Vegetable fibre . . . 344 Starch .... Green gluten Albumen .... Phosphate of lime Saccharine syrup Loss ..... 3840 • Jour, de Pharmacic, xxii. 386. f t'chlen's Jour. vi. 115. i X In tho samo state as that from the leaves of plants, and mixed with the green colouring niulter. § Gehlou's Jour. vi. 119. 90 22 mr 17i H 182 pe mu filt 61 poi cor vec •atod into thin ^WtM'tiH\>-i)itt«P in ul(M)ln>l luul lutionx in aliMi- r in acotii". acid ho air. Whou it«. I; niaiH contamH. boon \i,\sii\\ in a iiforo lioworinf?, itainrt a trac" "f aftor ttoworini?, iHMi the jjrain is stiU fjreini, ctm- i», having an ex- to a very conniion camincd in differ- ' attention to i\m manner witii Itiir- nstituents:— 3000 r>3 1 400 70 ar 3840 treatment, yi«W- 3840 n'8 Jour. vi. US. md mixed with the green I Bu'8 Jour. vi. 119. SKRUS AND I'llUITH. 885 The poafi thoniHclvcH, when very young, are often filled with a Mweet juice, which may lie obtained by a slight prcHsure. Einhof examined this licpiid. It haH a greoniMh-yellow (!olour and a very Hweet taHte. When expoHod to the air, tliin cutichss formed on its Hiu'face, and whito ttakes precipitated. It gradually underwent u kind <)f fermentation and he<;ame Hour. From 1440 [tarts of this juice, Kinhof obtained, by ahuiysis,* Albiunen 10 Extractive . . . . 18 SaechariiH! syrup . . .105 A.l» syruj) had much the taste of raw Hugar, but (;ould not be made to crystal lizo. From ripe peas, by macerating thcnn in water, an«l employing a mode of aiuilysis similar to that used for ascertaining the constitu- ents of barley, Kinhof obtained the following products. Tlie quan- tity employed was 3840 parts.f Volatile matter .... 540 Starchy fibrous matter, with tho coats of the peas . . . K10 Starch 1205 Animo-vegetable nuitter . . 559 Albumen . . . . 66 Saccharine matter . . . 81 Mucilage 219 Earthy phosphates . . . 11 Loss 229 3840 Tho second of these constituents, entitled starchy fihroua matter, was what remained after the peas, reduced to a jjulp with water in a mortar, bad been washed with water till thev ceased to discolour It, or to give out any solublo matter to it. This residue was in part comj)()8ed of the coats of the peas, nnd partly of a .vhite fibrous matter wiMiout taste or smell. When drieJ, it became yellowish, and was easily reduced to powder ; and the powder formed a paste with water, and dissolved like starch in hot water. It then bore a certain resemblance to starch, and agreed in its properties with the fibrous matter of potatoes.J The fourth of the preceding constituents, entitled animo-VfO^table matter, was obtained in thi^ manner : the milky water in which the peas had been macerated, after depositing the starch, still continued muddy, but neither deposited any thing, nor would pass through the filter ; but when diluted with its own bulk of water, it gradually de- posited a powder, the whole of which, being collected on a filter, constittited the substance to which Einliof gave the name of animo- vegetable matter. It approaches most nearly to gluten ; but as it differs in several particulars both from gluten and from all other vegetable constituents, we must consider it as a peculiar principle. * Gehlen's Jour. vi. I'JO. f Und. 13. t- Ibid. 123. (n|i HI i 1 HI i ' i pi H'l if! . 1 1 ,- i ' 1' l{' ■ i ■ nl K { f! j !> ' 1 - w .,; 1 v' t ^, t i in ; i ( i ! ■ ^ 1,. ^1 ; ^ i < ■ 1 it: i I i)» 1- ' ^ 'T- tni '. : !'! - i I ■ : UI^ 1 ^ ;.'! 886 SEEDS AND FRUITS. 1^* J* I Its colour was at first white ; it had no taste nor smell, but red- dened vegetable blues, even after having been repeatedly washed in cold water. It was glutinous and adhesive, and could be kneaded into a paste. It was insoluble in water, both cold and hot ; but when n^ixed with that liquid it soon putrefied ; and on being treated with lime, gave out the smell of ammonia. In the pure alkaline leys it dissolves readily, and forms a kind of soap ; but the carbon- ates require heat to produce the solution. Sulphuric acid dissolves it ; the solution is light-brown, and when diluted with water, lets fall a white thread-like substance. It dissolves also in muriatic acid and chlorine, and in acetic acid. Nitric acid gives it a lemon-yellow colour. It dissolves also in alcohol, and the solution becomes milky when mixed with water. The tincture of galls throws down a copi- ous white precipitate. Eiher and volatile oils have no action on it. When dried, it assumes a light-brown colour and the semi-transpa- rency of glue, and is easily reduced to powder.* Such are the properties of this substance, as far as they have been ascertained by M. Einhof.t When 3840 parts of ripe peas were reduced to ashes, the residue weighed 112 parts. From these ashes Einhof extracted phosphoric acid, sulphuric acid, muriatic acid, alumina, silica, carbonate of lime, phosphate of lime, oxide of iron, and phosphate of ammonia and magnesia.^ Braconnot analyzed peas in 1827, and obtained Skins • • 8-26 Starch . • • 42-58 Legumin • • 18'40 Water . • • 12-50 Animal matter, soluble in water, insoluble in alcohol • • 8-00 Pectic acid, with some starch . 4-00 Uncrystallizable sugar • • 2-00 Chlorophylle . • • 1-20 Pulpy skeleton • • 1-06 Bitter matter, soluble in water and alcohol • 9 a trace Carbonate of lime . • • 0-07 Phosphate of lime and potash, vege - table acid saturated with potash 1-93 100-00§ 8. The seeds of the viciafaba, a small bean, becoming blackisli when ripe, and used as an article of food, have likewise been ex- 1 amined by Einhof. The analysis was conducted in the same way as * Einhof remarks, that he has seen the gluten of wheat assume this appearance, I have observed the same thing twice. In both cases the wheat was very inferior j in quality, and had been the growth of a very rainy season. j- Gehlen's Jour. vi. 124. J Ibid. 182. p Ann. de Chim. et de Phys. xzzviii. 79. SEEDS AND FRUITS. 887 smell, but red- edly washed in uld be kneaded , and hot; but ,n being treated e pure alkaline hut the carbon- ic acid dissolves with water, lets in muriatic acid t a lemon-yellow n becomes milky c»ws down a coj)!- e no action on it. he semi-transpa- ' Such are the en ascertained by ashes, the residue racted phosphoric ica, carbonate of jhate of ammonia d 8-26 42-58 18'40 12-50 8-00 4-00 2-00 1-20 1-06 a trace 0-07 100-00§ , , becoming blackish i likewise been ex- in the same way as I assume this appearanct. e wheat was very inlenot I 9n. his other experiments already described. From 3840 parts of the ripe beans he obtained the following substances : — Volatile matter . . . 600 Skins 386 . Starchy fibrous matter . . 610 Starch 1312 Vegeto-animal matter . . 417 Albumen . . . . 31 Extractive, soluble in alcohol . 136 Gummy matter . . . 177 Earthy phosphate . . . 37^ Loss 133^ 3840* Fourcroy and Vauquelin, who made experiments upon this sub- stance likewise, founa the ashes which it leaves when incinerated, to consist of the phosphates of lime, magnesia, potash, and iron, and of uncombined potash. They could detect no sugar in it.f Vauquelin and Correa de Serra, made some experiments upon the bean in the year 1808.| They found in the skins of the bean, tannin striking a blue with the persalts of iron, animo-vegetable matter mixed with tannin, insoluble in water, but soluble in potash. The cotyledons contained a sweet-tasted substance, starch, legumin, albumen, an uncombined acid, with carbonate of potash, phosphates of lime, magnesia, and iron. The germen of the bean contained white tallow, legumin, albumen, phosphate of lime, and peroxide of iron. 9. Kidney beans, which are the seeds of phaseolus vulgaris, have been likewise analyzed by Einhof. They are characterized by the great proportion of animo-vegetable matter which they contain. From 3840 parts of these beans Einhof obtained the following sub- stances : — Skins 288 Starchy fibrous matter . . 425 Starch 1380 Animo-vegetable matter, not quite free from starch . . . 799 Extractive . . . . 131 Albumen, with some vegeto-animal matter 52 Mucilage 744 Loss 21 They were again analyzed by Braconnot, 38i0§ in 1827, who obtained id. 1S2. * Gehlen's Jour. vi. 186. f Ann. de Mus. d'Hist. Nat. No. xxxvii. 9. t Ann. de Chim. et de Phys. xxxv. 57. § Gehlen's Jour. vi. 545. II Ann. de Chim. et de Phys. xxxiv. 85. ' H \i 1 '\m i ; ' t , 888 8BED8 AMD FRUITS. Husks Starch ..... Water Leeumin .... Aniinul matter soluble in water, in- soluble in alcohol Pectic acid with legumin and starch Fatty matter .... Pulpy skeleton Incrystallizable sugar Phosphate of lime and potash, car- bonate of lime, vegetable acid united to potash . 7 42*34 23-00 18-20 5-36 1-50 0-70 0-70 0-20 1-00 100-00 Vauquelin analyzed a species of black kidney bean from the Isle of France. They furnished a dark-brown infusion, which left after evaporation a black residue mixed with grey crystals. If these crystals be picked out, dissolved in water and crystallized a second time, we obtain them in a colourless state. They are very volatile, when distilled give out ammonia, and are neither soluble in alcohol nor ether. The solution of these crystals strikes a green with the salts of iron, and lime water changes that colour into purple-red. The black substance which accompanies these crystals contains also azote. When dry it has a brilliant black colour, and is soluble un- altered in sulphuric acid.* 10. Lentiles. To Einhof, also, we are indebted for the analysis of the seeds of the ervum lens. From 3840 parts he obtained the following substances : — Fibrous matter . . . . 720 Albumen ... .44 Earthy phosphates, with a little albu- men 22 Extractive, soluble in alcohol . 120 Gummy matter .... 230 Starch 1260 Vegeto-animal matter Loss 1433 11 3840t Here the proportion of animo-vegetable matter is still greater than in the kidney bean. Lentiles were examined by Fourcroy and Vauquelin, but whether the same species as the preceding, they do not put it in our power to determine, as they omit the botanical name. The liquid in which the flour of these seeds was macerated was not acid : it had a slight and rather disagreeable taste, and was precipitated copiously by • Ann. de Chim. et de Phvs. xzxvii. 173. t Oehlen's Jour. vi. 542. SEEDS AND FRUITS. 889 )0 00 , :om the Isle of hicli left after tals. If t^^ese ^lUzed a second re very volatile, luble in alcohol , green with the into purple-red. :al3 contains also id is soluble un- for the analysis he obtained the 720 44 22 120 230 1260 1433 11 J840t still greater than lelin, but whether It it in our power le liquid in which Id: it had a slight Jted copiously by ,'s Jour. vi. 542. infusion of galls, chlorine, and sulphat'^ a iron. In short, it ex- hibited nearly the same phenomena as are described by Einhof. When the flour of lentiles is digested in alcohol, the liquid assumes a greenish-yellow colour, and a bitter acrid taste. When distilled it has the odour of vanilla very strongly, but acquires a disagreeable smell when mixed with water. The residue is greenish-yellow, has the appearance of a thick solution of soap, and a green oil swims upon the surface. The pod of the lentdes contains a portion of tannin.* 1 1 . Citrus aurantium, the orange^ and citrus medica, the lemon. These fruits are too well known to require any description. Thoutjh several parts of them are employed both in medicine, and in domestic economy, they have not yet been subjected to a rigid chemical analysis. The bitter oranges contain a peculiar bitter principle, which communicates the agreeable flavour that characterizes mar- malade. It is soluble in water and weak alcohol. It precipitates the persalts of iron of a deep-brown colour. It docs not precipitate tartar emetic, nor protochloride of tin. But the salts of lead and corrosive sublimate throw it down abundantly. It amounts to about 18 per cent, of the weight of the dry rind of the bitter orange. Unripe bitter oranges were examined by Lebreton, who found in them 1 A volatile oil 2 A fatty saponifiable oil 3 Chlorophylle 4 Hesperidin 5 Bitter principle 6 Gum 7 Lignin 8 Albumen 9 Gallic acid, trace 1 Citric and malic acids, partly combined with potash 1 1 Sulphate and muriates. The ash contained carbonate, sulphate, and muriate of potash, car- bonate and phosphate of lime, silica, and a trace of iron.f Lemon juice, according to Proust contains Water 97-51 . Citric acid .... 1*77 99-28 Besides bitter principle, gum and malic acid to the amount of 0-72 per cent. 12. Prunus cerasus &c., the cherry, &c. Berard has analyzed the unripe and ripe cherry, and obtained the following results : — * Annales de Mus. d'Histoire NaturcUe, No. xzxvii. 10. t Jour. de^Pliarmacie, xiv. 377. • H' '! ihl i.V" iu 890 SBBDS AND FRUITfl. I r. J, Chlorophyllo . Kelno CUiullb Chtrry. Unrlpa. nip*. t/nrlp*. RIpt. 0-27 — . 0-Ofi — Sugar . 0-(J3 11-61 112 18-12 Gum 4-22 4-85 6-01 3-23 Vegetable fibre 3-01 1-21 2-44 112 Albumen 0-41 0-93 0-21 0-67 Malic acid 0-08 MO 1-75 2-01 Lime traco trace 0-14 0-10 Water . 90-31 98-93 80-24 99-94 88-28 74-85 90-00 1 99-00 13. Amygdalua communis, the almond, peach and apricot trees. These three trees considered in a botanical point of view arc iden- tical, though the fruits are essentially diflerent. It has been sug- gested by Mr Knight, that this diflerence is the result of culture. In the peach and apricot, the outer rind or husk of the kernel has been converted into a delicious fruit, while in the almond the fruit lies within the stony covering, the husk being harsh and not fit for eating. The apricot and peach were analyzed by M. Berard, both in an unripe and ripe state, and found composed of Chlorophylle , Apricot, Peach. Unripe. nipe. Uiitlpe. 1 Ki|w. 0-27 — . 0-04 — Colouring matter . — — 0-10 Sugar . 0-63 11-61 trace 16-48 Gum 4-22 4-85 4-10 5-12 Vegetable fibre 3-01 1-21 3-61 1-86 Albun-jn 0-41 0-93 0-76 0-17 Malic acid 1-07 1-10 2-70 1-80 Lime 0-08 0-06 trace trace Water , 90-31 80-24 89-39 74-87 100-00 100-00 100-00 100-40 There are two varieties of almond, the bitter and the sweet. Bitter almonds were examined in 1817 by Vogel.* The husk amounted to 8-5 per cent, of the whole. When the almonds were pounded and heated in order to coagulate the albumen, 28 per cent. of a fixed oil (containing no prussic acid) might be obtained by ex- pression. But the whole of the fixed oil contained in the almonds could not be obtained in this way. The expressed residue being treated with boiling water gave out sugar and gum, and during the boiling, the oil containing hydrocyanic acid came over. To separate * Schweigger's Jour. xx. 39. id apricot trees, of view arc iden- It has been sug- result of culture, uf tbe kernel has almond the fruit •sh and not fit for Berard, both in an |lOO;OOJlOO;12J \tter and the sweet Lgel.* The husk [n the almonds were Ibumen, 28 per cent. I be obtained by ex- tned in the almonds [essed residue being Irum, and during the feover. To separate 8EEDS AND FIIUITS. 891 the fi^m from the sugar, the decoction was evaporated to dryness and treated with alcohol, which dissolved the s agar but left the gum. The sugar amounted to (5"5 per cent. It was easily fermented, but could not be made to crystallize. The gum weighed 3 per cent of the almonds analyzed. The matter exhausted of every thing soluble in boiling water, was treated with a dilute solution of caustic potash, which took up a quantity of albumen, after which drops of a fixed oil made the'r appearance on the surface of the liquid. The albumen weighed 3t per cent, and the vegetable fibre 5 per cent. The following table shows the substances extracted by Vogel, from 100 parts of bitter almonds Husk Fixed oil . 28-0 Albumen . 300 Sugar 6-5 Gum 3-0 Lignin 5-0 Heavy volatile oil Hydrocyanic acid — — 81 From the experiments of Robiquet and Boutron-Charlard,* there is reason to conclude that the volatile oil of bitter almonds does not exist ready formed, but makes its appearance during the processes to which tne almonds are subjected. When bitter almond i deprived of their fixed oil by expression are digested in alcohol, a peculiar crystallizable substance is dissolved, to which they have given the name of amygdalin, and which has been described in a preceding Chapter of this volume. Sweet almonds do not contain any amygdallin. Sweet almonds were analyzed by M. P-^ullay, in 18l7,t who obtained Water 3'5 Husk 5-0 Fixed oil . 54-0 Albumen , 24-0 Liquid sugar 60 Gum 30 Fibrin 4-0 Acetic acid and loss . 0-5 100 14. Pyrus communis and pyrus malus. The fruits of these well known trees are distinguished by the names of pear and apple. Pears were examined by Berard, and found to contain the very same constituents as peaches and apricots. The following table exhibits the results of his analysis. The first column gives the • Ann. de Chim. et de Phys. xliv. 332. f Ibid. vi. 406. H !! I! ■i :i .i 892 SEEDS AND FRUITS. I Ripe and Fre«h, Kept for some time. Putrid. 0-08 0-01 0-04 6-45 11-52 8-77 3-17 2-07 2-62 3-80 2-19 1-85 0-08 0-21 0-23 0-1 1 0-08 0-61 0-03 0-04 trace 86-28 83-83 62-73 100-00 99-65 76-85 constituents of fresh and ripe pears ; the second, of pears kept for sometime, which had lost a little carbon converted into carbonic acid by the oxygen of the air ; the third column exhibits the con- stituents of the same pears in a state of putrefaction. Chlorophylle Sugar . Gum Lignin . Albumen Malic acid Lime Water . Neither pears nor apples assume a blue colour when treated with iodine, showing that they do not contain starch. It is obvious from the black colour struck frequently when pears or apples are cut with a knife, that they contain also tannin, or gallic acid, or both. They contain likewise pectic acid and malate of potash. The fermented juice of apples is called cyder. It is specifically he;^vier than water, assumes a brown colour, when concentrated by evaporation, and deposits a blackish-brown powder, and leaves a thick brown syrup. Cyder contains alcohol, incrystallizable sugar, gum, extractive, malic acid, bimalate of potash, malate of lime, a trace of phosphate of lime, and of sulphates and muriates.* 15. Ribes grossularia, nigrum^ and rubrum. The fruits of these well known species of ribes are distinguished by the names of gooseberry, black currant, and red currant. Gooseberry and currant bushes are distinguished by the prickles which are present in goose- berry, and wanting in currant bushes. Green gooseberries have been analyzed by Berard, who examin- ed the berries both before they were ripe, and when ripe. The constituents found in the two states were the following : — Unripe. Ripe. Chlorophylle . Sugar 0-03 0-52 6-24 Gum 1-36 0-78 Albumen . 1-07 0-86 Malic acid 1-80 2-41 Citric acid 0-12 0-31 Lime 0-24 0-29 Fibrin,(including the seeds) Water . 8-45 86-41 8-01 81-10 100-00 100-00 * Payenstecher, Schweizcr Naturwiss. Anzeigcr, Jahrg. iv. 89. SEEDS AND FRUITS. 893 ars kept for to carbonic its the con- Putrid. 004 8-77 2-62 1-85 0-23 0-61 trace 62-73 76'85 treated with , obvious from 53 are cut with . both. They is specifically )ncentratetl by and leaves a allizable sugar, ^ate of lime, a iates.* The fruits of the names of •ry and currant esent in goose- 1, who examin- en ripe, ag:— H IS G 1 n! The 11 LO' vs 0! IT. iv. 89. 16. Vitis vim/era. Grapes, the well known fruit of this plant have not yet been subjected to a rigid chemical examination. The expressed juice of grapes, according to Scheele, contains no other acid but the tartaric, a statement which has been confirmed by Bra- connot. Berard found in this juice from ripe grapes, an odorifer- ous substance, sugar, gum, albumen, malic acid, and malate of lime, tartaric acid and tartrate of lime. 17. Mangifera indica, or domestica. The fruit of this tree, the mango, is a well known fruit of India, varying from the size of an apricot to that of a Bonchretien pear. It is oblong, subreniform, and marked by a longitudinal sulcus, which extends over |ths of the fruit. Its skin is soft and smooth, and has a yellowish colour. When the mango is ripe, this skin is easily removed, and the fleshy part of the fruit is exposed to view, having an orange-yellow colour, full of juice, and having a very sweet and acidulous taste. The fleshy part of the fruit is full of long filaments, implanted in the envelope which covers the seed of the mango. This seed is kidney- shaped, and is covered witli a kind of white skin. It has a dis- agreeable styptic taste, similar to the fruit of the horse-chesnut tree. The fleshy part of the mango contains a great quantity of crys- tallizable sugar, citric acid, and gum. The aromatic principle which resides in the skin of the fruit is very fugitive, and cannot be pro- cured by distillation. The seed of the mango has been analyzed by M. Avequin.* He extracted from it the following constituents : — Albumen 0*04 Gallic acid 10-00 Tannin . . . . . . 0-37 Starch ...... 36-93 Gum 2-88 Stearic acid 2-34 Green resin 0-28 Brown resin 0*37 Butter . . . . . . 1-74 ," Extractive colouring matter, tannin, and 7 q.qq gallic acid 5 Lignin 5'89 Water 28-59 98-52 . The quantity of gallic acid in the seeds of the mango is very re- markable. M. Avequin proposes the following method of extract- ing it : Take a pound of seeds of mango, reduce it to powder, and pass the powder through a seive. Digest this powder for 12 hours in 4 lbs. of water. The temperature of the water should not exceed ' * Ann. de Chim. et de Phys. xlvii. 20; and Jour, de Pharmacie, xvii. 421. W-\ i. ■ M 'M "i;> « 894 SEEDS AND FRUITS. 122°. Filter and make a second infusion similar to the first, with 2 lbs. of water. Subject the undissolved matter to pressure, to ex- tract all the liquid from it. Mix together all these liquids and evaporate them over the vapour bath, till the whole does not exceed a pound. Clarify with two whites of eggs beat up in eight ounces of water. Then filter and evaporate the liquid to the consistence of treacle, on this residue pour 3 lbs. of alcohol of the specific gravity 0"837, and stir the whole strongly with a glass rod. Let the whole settle for 12 hours and then filter. Put this alcoholic solution into a distilling apparatus, and distil till only 6 ounces of liquid remain in the retort. Leave it at rest. In 48 hours the gallic acid will crystallize. Collect the crystals formed. Let them diain, dis- solve them in distilled water, and add to the solution ^th of their weight of animal charcoal, previously digested in muriatic acid, and carefully washed. Boil for 10 minutes, filter, and evaporate. The gallic acid will now form pure crystals. We may obtain the gallic acid from the seeds of the mango with- out employing alcohol. The preceding process is followed : — We evaporate the clarified aqueous solution to six ounces, and set it aside for 3 or 4 days. The acid crystallizes, and may be purified by the process just stated. Gallic acid exists in much greater quantity in the seed of the mango than in any other known vegetable, and if it ever should be-- come an object of commerce, it is from these seeds that it ought to be extracted. The stearic acid was obtained by digesting the seeds, previously exhausted by water, in boiling alcohol. The greater part of the alcohol was distilled, and the remainder being left at rest, the stearic acid gradually separated from it and floated on the surface of the liquid. It was washed with water, and then filtered hot through blotting paper. It was soluble in hot absolute alcohol, ether, and acetic acid of the specific gravity 1*063, and crystallizes as the solution cools. When treed from a brown resin which it contained, at first it was white, solid, without taste or smell, melted at 158°, and crystallized in silky needles on cooling. It was insoluble in water, soluble in fixed oils, and readily formed soap by uniting it with bases. Tlie substance called butter by M. Avequin was extracted from the seeds previously exhausted by water and alcohol. They were treated with ether. The ether being distilled off, a matter similar to hog's lard remained in the retort, having a yellow colour. It was washed with alcohol of 0*837 to remove the colouring matter. It was then quite white, melted at 86°, was soluble in hot ether, but insoluble in rectified spirits. It exactly resembled butter of cocao. 18. Amomum granum paradisi. The fruit of this species of ginger, known by the name of grains of paradise^ is used in India, where the plant grows naturally, mixed with betel, to promote diges- tion. The taste is agreeable. When squeezed in the mouth the grains produce a pleasant coolness. They are angular, reddish- K^ ii^B^i SEEDS AND FRUITS. 895 !:?[' he first, with ;s8ure, to ex- Mid evaporate seed a pound, ces of water, ce of treacle, gravity 0'837, .et the whole iholic solution noes of liquid the gallic acid lem didin, dis- n ^th of their riatic acid, and raporate. The be mango with- followed :— We and set it aside ! purified by the the seed of the , ever should be- that it ought to jeeds, previously sater part of the |fc rest, the stearic [e surface of the red hot through brown externally, but white within. They have an aromatic odour. They are arranged in two rows in each of the three compartments of a capsule, having nearly the shape of a fig. These grains have been analyzed by M. Wiilert. When distilled they give 0*5 per cent, of their weight of a volatile oil, of a light- yellow colour, and a camphory smell, and a hot penetrating taste. It is soluble in about 9 times its weight of anhydrous alcohol, and is pretty soluble in water. Alcohol extracts from the grains of paradise, a notable quantity of resin and extractive. If we mix the solution with water, and distil off the alcohol, the resin is deposited while the extractive re- mains in solution. This resin weighs 3*4 per cent. It is brown coloured and always remains soft. It has no smell, but its taste is exceedingly acrid and burning, and remains long in the mouth. The weight of the extractive which remains dissolved in the water is 1'15 per cent. It has a brownish-black colour, and when dis- solved in water leaves apotherae. It precipitates protosulphate of iron, of a blackish-green colour ; the protochloride of iron, of a deep brown ; the protochloride of tin, brown; and the acetate of lead, yellow. The residual portion of the grains contains so much mucilage that it swells in watc, and is converted into a thick mass, which can neither be filtered nor separated by decantation from the insoluble lignin. The total weight of these two substances is 83 per cent.* 1 9. Piper nigrum. This is the name of the plant which produces common pepper. It is a shrub which grows in India. The seeds, are berries, round, hard, having an aromatic smell, and a hot acrid taste. These berries constitute pepper. The unripe berries are the common hlack pepper, while the ripe berries deprived of their epidermis constitute white pepper. Pepper was examined in 1819, by M. Orstedt, who detected in it a substance to which he gave the name o( piperin, and T7hich has been described in a preceding Chapter of this volume. In 1821, M. Pelletierf published an elaborate examination of pepper. He showed that it contained the following constituents : Piperin A solid very acrid oil A balsamic volatile oil A gummy coloured matter Extractive, similar to that obtained from leguminous seeds Malic and tartaric acids Starch Bassorin Lignin Earthy and alkaline salts in small quantities. M. Pelletier showed that the piperin did not possess alkaline characters as Orstedt had supposed, but that it was a peculiar • Berzelius, Traite de Chimie, vi. 293. f Ann. de Chim. et de Phys. xvi. 337. i I ;4ih iUi: h !:'■ M 896 SEEDS AND FRUITS. m principle. He found too, that pepper owed its peculiar taste to a volatile oil. This I had shown many years before.* 20. Piper hyngum. Long pepper is the fruit of the piper longum, a shrub which is a native of Bengal. It was in it that Orstedt dis- covered pfpenn. M. Dulong d'Astafort afterwards analyzed long pepper, and obtained Pipeci.^ An pcrid fatty matter Vols^tile oil Ex'rr active Gum Starch / Bassorin in abundance A malate and some other salts.f 21. Piper cubeba. Cubebs are the fruit of the piper cubeba, a perennial shrub which grows in the Philippine islands, in Java, Guinea, and the Isle of France. The cubebs are berries, round, dry, and of the size of pepper corns. They have a blackish-grey colour, wrinkled, and stand upon short peduncles. The external bark, easily broken, covers a blackish skin, which envelops a white and oleaginous kernel. The smell is agreeable and aromatic, the taste aromatic and rather acrid. These berries were examined by Vauquelin,t in 1822. He extracted from them the following sub- stances : — 1 A volatile oil, which was nearly solid 2 Resin, like that from balsam of copaiva 3 Another coloured resin 4 A coloured gummy matter 5 Extractive, like that in leguminous plants 6 Some saline substance. This fruit has been lately examined by Cassola,§ who has ob- tained from it a peculiar substance, to which he has given the name of cubebin. It may be obtained in the following way : — Boil 1 part of cubebs with 4 parts of alcohol, filter, press out the liquid, and distil off the alcohol. Mix the liquid remaining in the retort, while boiling hot, with acetate of lead. Wash and dry the precipitate, and treat it with alcohol. When the alcoholic liquid is evaporated, the cubebin is deposited. It has a green colour, and the consistence of turpentine. Its taste is at first sweet, and then burning, like that of cubebs. It dissolves readily in anhydrous alcohol, and in ether, but it is almost insolu- ble in boiling water, though it gives its taste to that liquid. It melts at 68°, and at 86'^ it begins to boil, and may be volatilized in a white smoke, which forms a syrupy liquid. It is quite neutral, and is the substance that gives cubebs their peculiar properties. It congeals at 5°. . , . * Nicholson's Jour. ii. 7. f ^om. de Pharmacie, xi. 52. X Annals of Philosophy (second series), iii. 202. $ Jour, de Ch. Med, x. 685. SEEDS AND FRUITS. 897 Ml taste to a ler Imgum, irstedt dis- ilyzed long ]per cubeba, a tid9, in Java, lerries, round, blackisb-grey The external ivelops a white i aromatic, the re examined by 5 following suh- ia S who has ob- L given the name ('^.^Boillpart t the liquid, and \ the retort, while fv the precipitate, |id is evaporated, pentine. Its taste ^ebs. Itdissolv is almost insolu- bt liquid. lt«el^ Lilledinawbi^ Itieutral, and is tbe Vies. ItcongeaU fc:T/chrMed:x.0B5. Cubebs have'been lately analyzed by M. Monheim.* He obtained 1 Waxy matter ... 3 2 Green volatile oil 3 Yellow volatile oil 4 Cubebin 5 Balsamic resin 6 Chloride of sodium 7 Extractive 8 Lignin . 2-5 1-0 4-6 1-5 1-0 6-0 65-0 84-5 22. Capsicum annuum. The fruit of this plant, which is a native of India, but cultivated also in America and the West Indies, con- stitutes what is called Guinea or Cayenne pepper. It is smooth and elongated, of a lively-red or yellow colour, vesicular, bilocular, of very varying shape, and inclosing numerous flat seeds. It has no smell, but its taste is bitter, acrid, and burning. Guinea pepper was first analyzed by Bucholz,t who obtained the following constituents : — Wax ... Acrid soft resin Bitter aromatic extractive Extractive with some gum Gum Fibrin Albumen Water 7-6 4-0 8-6 21-0 9-2 28-0 3-2 12-0 93-6 In 1817 it was analyzed by Braconnot.| He obtained from it the following constituents : Starch ..... 9 A vci'y acrid oil ... 1'9 Wax with red colouring matter . 0*9 Gum of a peculiar nature . 6*0 Animalized matter . . . 5*0 Citrate of potash . . . 6'0 Lignin 67*8 Muriate of potash ") Phosphate of potash 3 * ' 10-0 - The acrid oil is the constituent to which the Guinea pepper owes its peculiar taste. It has been called capsicin. When heated it melts into a very fluid substance, and when the temperature is raised still higher, it is dissipated in fumes. Half a grain of it volatilized in a large room, causes all who respire the air of the room to cough and sueeze. When long exposed to the air and light, it becomes hard. Chlorine whitens it. It is slightly soluble in water, espe- * Jour, tie Pharmacic, xx. 403. f Tasclicnbuch, 1816, 1. I Anil, dc Chim. et do Pins. iv. 122. 3m i\W i« i^?4^'# 898 SEEDS AND FRUITS. ■ eially when mixed with the other principles of the Guinea pepper. The solution has the acrid and burning taste of the pepper. It is very soluble in alcohol, ether, oil of turpentine, and the caustic alkfllies. These solutions have a reddish-brown colour. With baryies it pre 'ipitatcs under the form of an iuHoiuble compound, having an acri 1 taste. It is slightly solubl- in vinegar. 23. Myrlns tiimento. The fruit of this trse, ^ hlch is a na- ivi;' of the We.-i Indies, is known in this country by tlu; name of JrtH-i'ca pepper. The berries .ir(» puiied uad driea i)d'Hi-. th; arc r've. They are wrinkled, a little In j;er tiian the grains of black jicpjer, globular or obloii^r, and of n deep-brown colour. They hava an odour and taste, which seonu- lo be a mixture of that of pepper, cinnamon, and cloves. It was subjected to a chemical nnalys'., by Bonaitrc;* who jx- amined separately tho skin and the kernel. Cold alcohol extracts, from the en^e^i|'e, tannin, a; - a ;->oft green n;sin, which is deposited during i]vi csaporailon ui' the ali;ohol. i-oilir,*'- ;dcohol '-eing applied afterwards, ilissoived a little green resin avA ,a solid fat oil, which was deposited in iiocks during the cooling of ti c alcohol. Tho grec.'i resin has the burning and aromatic taste which charac- terizes Jamaica pepper, and a rancid odour, but somewhat analogous to that of cloves. It is no doubt a mixiare or compound of volatile oil and resin, and probably contains other substances besides. The- tannin dissolved in alcohol, strikes a green colour with the persalts of iron, and precipitates tartar emetic. The husks, .after bcinjr exhausted by alcohol, swell considerably wlum put into ammonia, and the alkali dissolves a brown matter, whi(;h precipitates in brown flocks. Jamaica pepper when distilled yields a volatile oil. Bonastre employed the same method to analyze the husk and the kernel of the seeds. The following table shows the result of these analyses. Volatile oil Husks. Kernels. 10-0 50 Soft green resin .... 8-0 2-5 Solid fat oil .... . 0-9 1-2 Extract containing tannin . 11-4 39-8 Gum 3-0 7-2 Brown colouring matter extracted by potash 4-0 8-8 Resinous matter .... 1-2 3-2 Extract containing sugar . 3-0 8-0 Malic and gallic acids 0-6 1-6 Lignin 50-0 16-0 Ashes containing salts 2-8 1-9 Moisture 3-5 3-0 1 98-4 98-2 ♦ Jour, de I'harmacic, xi, 180. SEEDS AND FRUITS. 899 lea pepper )per. It 13 the caustic 3ur. With rompou"^' s anati^' of 5 of J'i*' vca .,,, arc E've. jlack V'cpver, rhey l^ava an at 01 pepi^ev, ,tre,* who ^x- 1 a soft green j: the alviohol. ittle green resin •ing the cooling ,c ^vlnch charac- ewbat analogous pound of volajAc es besides, ij;"^ ivvitb the persalts Us, after bein? ito ammonia, ami ■sin brown flocks. leoii. BonasUe Itbekerneioftlie lese analyses. 24. Tamarindus Indica. Tamarinds consist chiefly of a pulpy matter which fills the pods of the tamarindus Indica, and covers the seeds. It is brought to Europe preserved in sugar. We are indebted to Vauquelin for an analysis of this substance, published however at a very early period of his chemical career. By treating the pulp of tamarinds, such as they are sold by the apothecaries, first with cold water, and afterwards with hot, he separated the fol- lowing substances : — * Gum . . . . 432 Sugai 1152 Jelly 576 Citric acid 864 Tartaric acid . 144 Malic acid 40 Feculent matter 2880 Water 3364 9752 Scheele found no citric acid in the pulp of the tamarind; he found only tartaric acid. 25. Juniperus communis. This shrub, which grows wild in Scot- land and other northern countries, bears the well-known fruit, called Juniper berries. They contain a volatile oil to which they owe their taste and their value, being employed to communicate that peculiar flavour to Dutch gin. It exists chiefly in the green berries. In the berries which have become black that oil is converted into resin. When the berries have a deep blue colour they contain a good deal of sugar, but in the dried black berries it has almost disappeared. Juniper berries were analyzed by Trommsdorf,t who found in the berries, just on the point of being ripe. Volatile oil .... 1-0 Brittle wax Green resin A peculiar species of sugar Gum Lignin 4-0 10-0 33-8 7-0 35-0 90-8 The volatile oil has been described in a preceding Chapter of this volume. ■" The sugar crystallizes with difliculty in grains. It has a honey- yellow colour. Its taste is less sweet than that of grapes. It dis- solves in boiling alcohol, and is mostly deposited as the liquid cools. It is insoluble in ether. It ferments readily when its aqueous solu- tion is mixed with yeast. This sugar, as obtained from juniper berries, is mixed with a peculiar extractive substance, having an r^i^'im n m lillf t\ ^l i L> ml P4M Ann. de Chinti. v. 92. t Tiischcnbuch, 1822, [>. 4;3. "v.-^^ 900 SEEDS AND FRUITS. acrid and aromatic taste, and with acetate of potash. This sugar may be obtained by macerating the bruised berries in cold or warm water. Juniper berries were analyzed also by M. Nicolet, who obtained* A volatile oil Sugar Wax Resin. The wax was composed of Carbon . 65-400 or 13 atoms Hydrogen 7-3227 or 8^ atoms Oxygen . 27-2773 or 4 atoms 100 The resin was crystallized and composed of Carbon . . 75-04 or 5 atoms Hydrogen . . 5-1037 or 2 atoms Oxygen . . 19-8563 or I atom. 100 26. Pimpinella anisiim. The seeds of this umbellated plant, whicli is a native of the Levant, arc well known by the name of anise. It is chiefly cultivated in Spain and Malta, whence the anise seed is imported into this country. It is cultivated also in the south of England. Anise seeds have an :.romatic smell and ii pleasant warm taste, accompanied with a considerable degree of sweetness. These seeds were chemically examined by M. B andej. When digested in boiling alcohol till every thing soluble is taken up, the solution being left to itself, after distilling off the greatest part of the alcohol, deposits 0-125 per cent, of concrete fixed oil, together with chlorophylle. When still farther concen'rated it yields 3-55 per cent, of a green-coloured fat oil, showing from its taste and smell that it contains some volatile oil of anise. This fat oil has a buty- raceous consistency. It dissolves readily in alcohol, leaving 0-1 "5 of a brown residue, mixed with malate of lime and malate of potash, Caustic alkalies convert it into soap, iutting fall a white flocky sub- stance which has not been examined. The solution remaining, after the separation of the oils, gave, by evaporation, a brown ex- tract soluble in water. From this extract anhydrous alcohol dis- solved a small quantity (0*15) of a resin, and 0-4 of bimalate and binacetate of lime. The residue, insoluble in anhydrous alcohol, was completely soluble in water. Alcohol precipitated from that solution 0-65 of grey flocks, v/hicli became black when dry. This substance contains azote, for when heated it gives off" ammonia. It is very soluble in water, and the solution, which has a brown colour, froths much when agitated. | * Jour. (Ic Phannacic, xvii. flIO. SEEDS AND FRUITS. 901 ;o\d or warm ho obtained* 03 ns [BS. itns oms OTO. ated plant, which e name of anise. vhence the amsc vated aUo in the latic smell and a derabie degree ol Bande3. When lie is taken up, tk Neatest part oftk d oil, together wi* it yields 3-55 per ' its taste and smell kfatoilhasahutv- ohol, leaving 0-1.3 '.dmalateofpotiisi ^ white ilock>( sub. solution remaining, ration, a brown ev vdrous alcohol dis- 6-4 of bimalate an ' anhydrous alcohol,! lof grey flocks, v/luAl L in water, and * I Lch when agitate^' It 13 precipitated by nitrate of silver, acetate of lead, and infusion of nut-galls. The liquid remaining, after the precipitation by alcohol, gave, when evaporated, incrystallizable sugar, mixed with extractive. This sugar amounted to 1 per cent, and fermented readily when mixed with yeast. What remained of the anise seeds after the action of alcohol, was boiled in water till every thing soluble in that liquid was taken up, and the decoctions evaporated to the consistence of an extract. This extract was taken up by a little water, and alcohol added as long as a precipitate continued to fall. A substance was in this way separated, which, when dry, was deep-brown, hard, had a vit- reous fracture and a faint smell and taste. It was gum, mixed with a small quantity of phosphate of lime and malate of potash. It amounted to 6*5 per cent. The residual liquid being left to spontaneous evaporation, de- posited 1 per cent, of bimalate of potash in small granular crystals ; and when evaporated to dryness, left (j'b per cent, of brown matter having a bitter, acrid, and saline taste. It absorbs moisture from the air, and dissolves completely in weak .alcohol. But it is insolu- ble in absolute alcohol and in ether. Its aqueous solution is not precipitated by corrosive sublimate ; but it is by nitrate of mercury and diacetate of lead. Nitrate of silver and sulphate of copper throw it down in brown flocks. It is precipitated abundantly by infusion of nutgalls. It consisted of extractive, salts, and a sub- stance precipitable by infusion of nutgalls. The residue of the seeds thus exhausted, first by alcohol and then by water, was treated with muriatic acid which dissolved phosphate of lime and a vegetable acid salt of lime, coloured brown by a little extractive. The weight of the whole of this mixture was 1'97, and that of the phosphate of lime 1"35. The residue was now treated with a weak boiling solution of caustic potash, and left an insoluble residue of 35*9 per cent of lig- nin. The alkaline solution neutralized by acetic acid gave a pre- cipitate weighing 8*6 per cent. When dry it was deep brown. Its taste was weak but astringent. It was insoluble in water, alcohol, ether, and acids; but soluble in caustic alkalies and in alkaline car- bonates by the assistance of heat. Brandes has distinguished this substance by the name of ulmin of the anise. The liquor precipitated by acetic acid being evaporated and treated with alcohol, left 2*9 per cent, of a reddish-brown substance, destitute of smell, insipid, and very soluble in water. It may con- sist of starch, altered by the processes of the analysis. Brandes has given it the name of gummoin. But it seems to have little analogy with gum. Besides the above-mentioned substances, Brandes found 3*5 of silicate of iron, 3 of volatile oil, and 23 of water. The following table exhibits the constituents which he obtained : — ^1 I m I'M (! f r 1 r^ m 902 SEEDS AND FRUITS. Concrete fixed oil . 0-126 Green fat oil . 3'560 Resin .... 0-160 Bininlate and binacetate of lime 0-400 Azotized substance . 0-650 Sugar .... 1-000 Gum .... 6-600 Bimalate of potash . l-OOO Extractive, with salts, &c. 6-500 Phosphate of lime, &c. 1-970 Lignin .... 35-900 Ulmin of anise 8-600 Guranioin 2-900 Silicate of iron 3-600 Volatile oil . 3-000 Water .... 23-000 97-745 27. Sinapis alba and w»V/m. These two species, both natives of Great Britain, and too well known to require description, pioducc the eeds in such general use under the name of mustard. The nigra produces the common black mustard. The saeds of the alba are largest and of a light yellow colour. Whea these seeds, of either species, are bruised and their fixed oil expressed, the residue constitutes the common condiment well known by the name of Dur- ham mustard* The sinapis alba seeds, according to the analysis of John, con- tain 1 An acrid volatile oil 2 A yellow fixed oil 3 Brown resin 4 A very little extractive 6 A little gum 6 Lignin 7 Albumen 8 Phosphoric acid and salts.f The constituents of the seeds of sinapis nigra, or common mus- tard, are much the same. MM. Henry and Garot, several years ago, announced that they had extracted from the seeds of white mustard a peculiar acid, which they distinguished by the name of sulphosinapic acid, the properties of whi'h they described, and among other peculiarities • The mustard of the shops is said to be often mixed with wheat tiour and cayenne pepper to heighten the flavour. It is said also to contain salt, but I could detect none in what is sold in Glasgow. When mustard is dried, it assumes a very deep brownish-orange colour. Mkalies restores the yellow colour. Muri- atic acid destroys the colour allogetlat and forms a complete solution. I could detect no turmeric nor cayenne pepper in the specimen which I examined. t Chem. Schr. iii. 153. 8RK' S AND FUOITS. 903 15 iO )0 )0 50 00 00 00 .00 )70 )00 300 1)00 500 000 000 •H5 . . , both natives ot criptlon, produce f mustard. The saeds of the alba A these seeds, of •essed, the residue the name of Dur- ms of John, con^ or coraraon mus- Inounced that they Id a pecuhar acid, losinapic acid, the [other peculiarities with wheat Hour and to contain salt, but 1 Lrd is dried, it assumes i yellow colour. Mim- lete solution. I couW Ich I examined. they stated that it struck a red with the persalts of iron. This ob- servation led M. Pelouzo to examine mustard. He found in it sulphocyanate of lime, and concluded that the acid described by Henry and Garot was hydrosulphocvanic. These observations induced Henry and Garot to resume their examination of mustard. They found tliat it neither contained sulphocyanite of calcium, nor sulphosinapic acid, but that there exists in it a pecidiar crystalliza- hli; body, to wliich they gave the name of svlphosin plain; but which has been shortened by Mor/elius into sinapin. The metliod of pro- curing this substance and its characters, have been given in a pre- ceding Chapter of this volume. The observations of Henry and Garot have been confirmed and extended by Faurl f % m il,; \:'1x i-:>^ nr P12 SEEDS AND FRUITS. i H ■ m 11 1 m ml few hours, the liquid deposits a sediment, which is claterium. It should be carefully dried in a warm place spread upon linen cloth. The extract from the inspissated juice is mixed in the elaterium of the shops. Elaterium was analyzed in 1817 by Braconnot.* He found that when the expressed juice is boiled, coagulated albumen is deposited. When the liquid was evaporated, he obtained an extract composed of 40*3 parts of a peculiar bitter principle, and 34*7 of a matter in- soluble in alcohol, and precipitable by infusion of nutgalls. He obtained also 6'9 parts of nitre, 2*8 of a salt of potash, the acid of which seemed to be the malic, 7 of a salt of lime saturated with the same acid, and 8*3 of sulphate and muriate of potash. The bitter principle is obtained by digesting the extract of ela- terium, in alcohol, which leaves the nitre and the substance preci- pitable by infusion of nutgalls. During the evaporation of the alcoholic solution, a little more nitre is deposited. The alcoholic solution being evaporated to dryness, the residue is dissolved in water, and acetate of lead is dropt into tlu- solution which throws down the malic acid and a portion of the matter precipitable by infusion of nutgalls. The filtered liquid is mixed with tartaric acid to throw down the oxide of lead and the potash. Being filtered again, it is evaporated to the consistence of honey. Alcohol being digested on this residue, the yellow principle is dissolved, while the tartrates are left behind. The alcoholic solution being evaporated, leaves the bitter principle still contaminated with a little nitrate and muriate of potash. The bitter principle thus obtained, has a brown colour, and a very bitter taste. It is very soluble in alcohol, but liHle soluble in ether. Barytes water, alum, and the metallic salts do not occasion a precipitate when dropt into its solution. With alum and potash it gives a yellow precipitate. The protosulphate of iron gives the solution a brown colour. Infusion of nutgalls throws down ca copious precipitate. About the year 1818, Dr Paris of London, and Mr Faraday, made a set of experiments on elaterium, f from which it appears that the active principle in the fruit is a peculiar substance, to whicli they have given the name of elatin. They found that alcohol of 0*817 dissolves from t^i> extract from the juice of the fruit 12 per cent, of matter. The alcoholic solution is green, and yields when evaporated a green residue, from which boiling water extracts a small quantity of a very bitter substance, which give« it a yellow- ish-brown colour. The insoluble portion is a green resin, soluble in alcohol and precipitated from this solution by water. This is the substance to which the name of elatin has been given. Its colour is green, its smell disagreeable and its taste weak, One eighth of a grain of this substance is sufficient to act violently as a jjurgative. • Jour, de Phys. Ixxsiv. 292. t Paris' Pharmacologia (4th Edition), p. 373, SEEDS AND FRUITS. 913 Merium. It ,n linen cloth, e elaterium of | He found that sn is deposited, tract composed of a matter m- tralls. of potash, the '■ lime saturated 3 of potash. B extract of ela- substance preci- moration of the The alcoholic "e is dissolved in on which throws r precipitable by with tartaric acid I Being fiitered .' Alcohol being issolved, while the being evaporated, a little nitrate and own colour, and a ,ut llnle soluble in llts do not occasion h alum and potash L of iron gives the Is throws down a , and Mr Faraday, tiich it appears that substance, to which and that alcohol ot [of the fruit 12 per pn, and yields when L water extracts a Lgive. itayelow- Lreen resin, soluble Lter. This IS the Iffiven. , and its taste wed. kient to act violentl) M. Clamor Marquart, gives the following process for extracting this substance, to which he has given the name of elaterin : — The fruit, not yet ripe, is gathered in July, subjected to the press, and the juice evaporated to the consistence of an extract. This extract is digested in alcohol of 0"833. The alcohol is distilled off and the residue diluted with boiling water, gives, on cooling, crystals of elaterin, which cover chlorophylle. They are collected on a filter and the chlorophylle is separated by washing them with ether. Elaterin thus obtained, is crystalline, colourless, and almost insipid. When distilled, it gives off ammonia. It is insoluble in water, but easily soluble in alcohol. It is quite neutral, scarcely soluble in ether, very soluble in hot oil of turpentine, though little soluble in that oil while cold.* M. D. Morrusf had already extracted elaterin by a process nearly similar, but the characters oi his elaterin do not exactly agree with those of the elaterin of Marquart. In the portion of elaterium, insoluble in alcohol, Dr. Paris found Starch 28 Extractive 26 Albumen 5 Lignin ..... 2o Water 4 88 39. Myristica moschata. The well known fruit of this tree is the nutmeff, so much used as an article for seasoning food. The tree is a native of the MoUucca islands. But has been nearly extirpated by the Dutch, except in Sumatra and Banda, where enough is raised to supply Europe. The covering of the nut is known by the name of viace. The nutmeg varies in size and figure ; it is fur- rowed on the outside, and greyish-brown internally. Those that want white streaks are the best. From the experiments of Neumann, we learn that this substance contains two species of oil : a volatile oil, to which it owes its peculiar smell and taste, and which in his trials amounted to about -^^d part of the nut ; and a solid fixed oil resembling wax, and amounting to about ^d of the nutmeg. He de- tected also a quantity of gum ;| and it is probable, from the appear- ance of the kernel, that it contains likewise starch. By expression, the solid oil is separated, and mixed with the volatile oil. In that state it is sold under the name of oil of mace. The nutmeg has been analyzed by M. Bonastrc,§ who obtained Fat butyraccous oil . . . 31*6 Volatile oil . . . . G'O Starch 2*4 Gum 1*2 Acid 0-8 54-0 Lignia 96-0 m ■ I ria (4lh Edition). V .373. I* Jour, dc Pharmacle, xxii. CG5. f Ibid, xviii. 27. J Neumann's Chem. p. 404. § Jour, de Phann. ix. 281. 3n 914 SEEDS AMD FRUITS. It, The butyraceous oil has been described in a preceding Chapter of this volume, under the name of butter of nutmeg. 40. Myristica sebij'em. The fruit of this tree which is a nativo of Guiana, has been also examined by Bonastre, who found a con- siderable resemblance between it and that of the myristica moschata* He extracted from it A volatile oil A butyraceous muttor A sebaceous crystalline matter Gum Parenchyma An acid. 41. Canahis safira. The seeds of this ])lant which produces the connnon hemp, were subjected to a chemical examination by Bucholz. The followin<'" are the rcrfults which he obtained : — Sixteen parts of lienip-secd yielded by expression rather more than 3 parts of a yellow-colouied oil. Its taste was mild, and it possessed all the characters of the (ixed oils. From the residue he procured, hy digestion in water and coagulation by heat, about 3h parts of albu- men, and not quite ^ a pai' of fibrous matter. The insoluble coats and husks of the seeds wci>i lied (5 f\ parts. About fth of a part of a brown- coloured resin was obtained by means of alcohol, and about the same quantity of a substance to which Bucholz n^ives the name ni mucilagin- ous sugar, and soapy extract, and about 1 ^ part of gummy extractive.^ 42. I'liytolacea decandra, or Americaii night-shade. The berries of this plant give a beautiful purple colour to water, of a very fugi- tivo nature. A few drops of lime water change it to yellow ; and this yellow liquid is the most delicate test of acids hitherto observed. The smallest quantity of acid restores its purple colour. Bracon- not, to whom^ we are indebted for these observations, has shown, that it is at least four times as delicate as the infusion of lituiu!. Unfortunately it alters its nature in a few hours, and then loses \\i delicacy as a reactive. It can only be used when recently prepared.? 43. Menispermum cocculus (coccvliis suberosiis of Decandollej. The berries of this shrub, which is a native of the East Indies, are about the .size of a pea, and of a blackish or greenish-black colour, Under a thin covering they contain a white kernel. These benios | have scarcely any smell, but they have an acrid, burning, and bitter taste. They were examined in 1811 by BouUay, who disco\ ered in them a substance to which he gave the name of picrotoxin, am! which has been described in a preceding Chapter of this voliniie. In 1833 Pclletier and Couerbe discovered in the covering of tlie berries two new alkalie?, which they distinguished by the names of mmispirmina and jiarameiiispcrmina. These also have been de- scribed in a preceding Chajiter of this voUinie. Boullav found in these berries * Jour, de Pliarmacic, xix. 180, f Gchlens Jour. vi. Glo. J Ann, de Chim. Ixii, 81, ing Chapter of hicli is a native lio found a coii- isticamoschata. hicli proiluces the lation by Bucliolz. .^rather more than Id,auc\itpo3se8soa lue he procured, by It 3i parts ot aU)u- e insoluble coats and ,f apart of a brown- and about the same (.name of »«<«•%"(- f nummy extractive.] Jade. The berries ater, of a very iuf^i- ■e it to yellow ; and Is hitherto observed. le colour. Bracon- vations, has shown, infusion of htmuN •s, and then loses it» .recently prepared.; sus of Decandolk). the East Indies, are eenish-black coU.uv, ■rnel. These hemes f,burniu^^ and bitter I Jlay, ^vho discovere me of pfcrofom ami aptor of this voluuH the covermj? of tli ihedbythenanu>=^«l! also have been di- Ann. de Chim. Wi. 81. 1 SEEDS AND FRUITS. 915 A flit oil Tallow A yellow extractive matter Picrotoxiu Albumen Li(^niii Sulphates, phospli;ites, and muriates of potash and lirac. The ashes contained silica and peroxide of iron. IJouUay announced the presence of a peculiar acid in these bor- ries, to which he gave the name of menispermic acid. But Casascca could not find any traces of this acid, and ascert \ined that the tal- low, of which BouUay spoke, was a mixturo of oleic nd inargaric aciils. BouUay made a new set of experiments on these b^^ ,> .V^4 /#:v *j 1.0 I.I ^1^ 1^ IL25 i 1.4 1.6 Hiotographic Sciences Corporation 23 WEST MAIN STREET WEBSTER, N.Y. MS80 (716) 873-4503 : ; but deposits crystals in stars. Lxposed to the air for a month, it con- cretes into plates. It forms soap with the alkalies. The solid body is deposited when the alcoholic decoction of tin; seeds is allowed to cool. It is white, and has a pearly lustre. It has a sweet and agreeable taste. It dissolves readily in ether, from which, by spontaneous evaporation, it is deposited in small crystals in rays. Those crystals are surrounded by a transparent substance which does not crystallize. It melts at i)5°, and does not crystallize on cooling. The odorom bodf/ was obtained by washing, for a second or two, the residue of diti'erent alcoholic macerations of the seeds, after strong expression. When the alcohol was left to spontaneous eva- poration, the odorous matter was deposited. Its colour was light green, its consistence seraittuid at the temperature of 48°, and it became loss fluid when the temperature was sunk. It has a well characterized odour of musk. When left exposed to the air for somi; weeks its smell loses much of its intensity. M. Bonastre did not succeed in obtaining from it a volatile oil. The resin had a blackish-brown colour, an agreeable smell and ii pitciiy consistence. 53. Cardamum minus. The seeds of this plant, examined long ago by Neumann, were subjected in 1834 to a chemical analysis, by IM. J. B. Trommsdortt'.* He obtained the following substances : — 1 Essential oil ..... 4*0 2 Fixed oil 10-4 3 Salt of potash, probably malatc . . 2*5 4 Starch 3-0 5 Azotized mucilage with phosphate of lime 1*8 G Yellow colouring matter . . . 0*4 7 Lignin 77-3 lOO-O The essential oil could not be obtained from the capsules, but was from the seeds themselves, by distilling them with water. It was colourless, had an agreeable odour, and a strong aromatic burning taste. Its specific gravity was 0*943. It was very soluble in alco- hol, ether, the volatile and fixed oils. Concentrated acetic acid dissolved it abundantly, but it is insoluble in potash ley. It docs not detonate with iodine. When long kept, it becomes yellow and viscid, and loses its peculiar taste and smell. It then detonates witli iodine, and takes fire when placed in contact with concentrated nitric acid. The fixed oil was extracted by macerating the bruised seeds in ether for eight days. The greatest part of the ether and volatile oil was distilled otl'. The residue was left in a warm place to spontaneous evaporation. It was then distilled with water, to get rid of all the volatile oil. The fixed oil being freed from the water had a slightly bitter taste, gave a greasy stain to paper, was very * Annalen der Pharmacie, xi. 25. SEEDS AND FRUITS. 923 soluble in alcohol, and was disengaged from that solution by water. It was very soluble in ether, the volatile and fixed oils. Potash dis- solves it only when boiling hot, and the oil is separated unaltered by an acid. Nitric acid has little action on it when cold, but when heated gives out a deei)-red colour. When heated in a platinum ypot)n, it burns with flame, giving out much smoke. These choracters show an anaU)jxy between this lixed oil and castor oil. 54. Rhus coriaria, or sumac. M. Troramsdortt' has ascertained that the berries of this shrub, which have an acid and slightly as- tringent taste, contain a great deal of bitnalato of lime. M. Troinnis- dorif recommends these berries as one of tiie easiest means of getting pure malic acid. The berries are macerated in boiling water, the liquid llltored and evaporated. Crystals of bimalate of lime are obtained, which are purified by a second crystallization. This salt is dissolved in water, the lime tlirown down by potash, and the malic acid by acetate of lead. The malate of lead is decomposed by sulphuretted hydrogen, and the malic acid crystallized.* .05. Lithospennum officinale. The seeds of this plant have been long known for their remarkable hardness. And itappearsfrom the analy- sis of them, by Captain Lehunt, that they contain a greater quantity of earthy than vegetable matter. He obtained Carbonate of lime . . . 43*7 Silica 10'5 Vegetable matter, with phosphate of lime, oxide of iron, and traces of potash and manganese . . 39'8 ioo-of 5G. Melia sempervirens. The fruit of this shrub, originally from Syria, but common in the West Indies, is a drupe, about the size of a small olive. When ripe it has a greenish-yellow colour. It con- tains a kernel divided into 5 compartments, and containing 5 seeds. It was considered as poisonous ; but M. Ricord-Madianna has proved, by numerous trials, both on dogs and men, that not only the fruit, but every part of the plant is innocent.^ He extracted from the fruit of this plant Water 55*55 Chlorophyllo .... 2'77 Resin 0-66 SarcocoUiu .... 3'33 Mucus 0"17 Gum 5-55 Starch 3-89 Fixed oil .... 1-39 Lignin 25-55 Acetic acid .... trac e 98-86 * Ann. der Pharraacic.x. 328. i" Jameson's New Phil. Jour, for July 1832, p. 25. X Jour, dc Pharmacie, xix. 500. ■Apt- m \^ V \ ■>il i IF *" * ! I 'i ■i ii 924 SEEDS AND FRUITS. 11 Wl I; 67. Solanum hjcopersicum. The berries of this plant, which is a native of South America, though cultivated in Europe, are known by the name of love apples. They are round fleshy berries, having a yellow-red colour, containing a great number of seeds, inclosed in " ; SI ' i1fi 926 SEEDS AND FHUITS. 14 coloured liquid, on which awims an insoluble matter. The liquid contains sugar and a little malic acid. The insuiublc matter is washed in water. It is dissolved in alcohol, and cautiously satu- rated with dilute barytes water. It is filtered, to separate the salts of barytes formed, and a little nil. It is evaporated to dryness. The residue is the acrid matter. It has a yellow colour, and is still of a soft consistence. It has no smell, but a very acrid taste, which continues long in the mouth. It melts a little above 212°, and concretes again on cooling. It is insoluble in water, but soluble in alcohol in all proportions. The alcoholic solution has no action on vegetable colours. Water renders it milky. It dissolves in sul- pliuric and acetic ethers. The dilute acids have no action on it. The alkalies dissolve it. C2. Croton tiglittm. The seeds of this tree, which furnish the croton oil, were analyzed by M. Brandos, and found to contain A volatile oil Crotonic acid An alkaloid Colouring matter Stearin Wax A subresin Inulin Gum Gluten Tragacanth Albumen Do. coagulated Starch Phosphate of magnesia.* 63. Tanghinia Madagascariensis. The fruit of this tree, wlildi is a native of Madagascar, has been long known in that island for its poisonous qualities. It was subjected, in 1823, to a chemical analysis by MM. O. Henry and Olivier. f They extracted, by com- pression, a fixed oil, which becomes solid at 50°. When the residue is digested in ether, a peculiar crystallized matter is extracted, to which they have given the name of tanghicin. It crystallizes during the evaporation of the ether. Tanghicin is soluble in alcohol of 0*815, and crystallizes during the evaporation of the solution in transparent plates, which effloresce in the air and become opaque. It is insoluble in water. Its taste is at first bitter, then extremely acrid, and it leaves a sensation of r stringency in the throat. It melts when slightly heated, and in vliat state resembles yellow resin. It contains no azote. It is ji neutral substance, and seems neither to combine with acids nor al- kalies. When taken into the stomach, it acts as a powerful poison. When the portion of the fruit freed from the tanghicin by ether Jour, dc Phaniiac'r>, xi. 144. t Ibid. X. 49. gBRDS AND FRUITS. 92T The liquia I inattur U ously uatu- te the salts to dryncsis. , and is still taste, which 212°, and [t soluble in 10 action on Ives in sul- iction on it. furnish the contain 111. X. 49. is treated with alcohol, a brown viscid substance is dissolved, which contains a free acid. This substance contains no azote. Acids •rive it a green, and alkalies a brown colour. Hesidea these substances, tanjfhicin contains much albumen, a little gum, and traces of iron and lime. 04. Cassia acutifolia. The fruit of this plant, the senna of the Hhopa, has been oxamincd chemically by M. FeneuUe,* lie found it to contain 1 Cathartina 2 A colouring matter 3 A little albumen 4 Much mucilage 5 A fixed oil 6 A volatile oil 7 Malic acid 8 Malates of potash and lime 9 Chloride of potassium, sulphates, bonates of potash and limo subphosphatos, and car 10 Silica 11 Lignin. The cathartina is somewhat less in proportion, in the follicles or fruits of the cassia than in the leaves. G5. Bertholletia excelsa. The fruits of the tree, which is a native uf Brazil, constitute triangular nuts called Juvias. They consist each of a thin woody shell enclosing a kernel. They were sub- jected to a chemical analysis by M. Morin. f From the shell he extracted 1 Gallic acid 2 Tannin 3 Incrystallizable sugar 4 Acetate of potash 5 Gum 6 Several mineral salts. From the kernel were obtained 1 A fixed oil, composed of elain and stearin 2 A great quantity of albumen 3 Liquid sugar 4 Gum 5 Lignin. This ihows a striking analogy with the constituents of sweet almonds. (i6. Syringa communis. A very elaborate analysis of the fruit of this shrub, the common lilac, has been made by MM. Petroz and llobinet.J They obtained 1 Resin 2 Sugar 3 A substance which throws down iron grey Jour, de Pharmacie, x. 58. t Ibkl, 61. t Ibid. 139. rt m !i 'I 938 SEEDS AND FRUITS. if 4 A bitter principle & An insoluble jelly 6 Malic acid 7 Bimalate of lime 8 Nitrate of potash 9 Some mineral salts. The resin is much less easily dissolved in alcohol than common resins. They consider it as chlorophylle altered by vegetation. The sugar differed from common sugar in the form of its crys- tals, flat four-sided prisms, with an inclined base. The substance wnich precipitated iron grey, when dried, had a brown colour and great lustre. None of its other characters were noticed. The bitter principle had the property of changing solutions of protoxide of iron to green, but it produced no effect upon solution of the peroxide. It dissolved readily in acetic ether, but very im- perfectly in sulphuric ether. It was soluble in alcohol and water, and the aqueous solution precipitated the nitrate of mercury. It has no action on acetate of lead, but throws down subacetate yellow- ish-white. The jelly was semitransparent, insipid, inodorous, and almost colourless. It was insoluble in water, alcohol, ether, oils, and am- monia. Dilute acetic, nitric, and phosphoric acids dissolve very little of it. Nitric acid, when its action is long continued, converts it into oxalic acid. Its solution is precipitated by lime. It burns like gum. 67. Hura crepitans. The seeds of this tree, which is a native of India, but cultivated in America and the West Indies, are employed by the natives as a purgative. They act with great violence in general. The leaves give out a milky juice like the euphorbia. M. Bonastre subjected these seeds to a chemical analysis,* and •obtained 1 A fixed oil, slightly acidified 2 Stearin 3 Parenchyma 4 Gum . 5 Moisture 6 Saline residue 100 We do not see here the substance which possesses cathartic effects, unless we ascribe them to the fixed oil. 51-11 4-45 38-89 Ml 2-22 2-22 • Jour, do Pliarmaclc, x. 479. KICitNfl. 020 CHAPTER XIII. an common fetation, of its crys- Iried, bad a •acters were solutions of Eon solution ut very ini- l and water, ncrcury. It etate yellow- !, and almost oils, and ani- dissolve very lued, converts It burns ne. i is a native of are employctl it violence in aupborbia analysis,* and Isses catbartic () i- F t u N s. , :i Vehy few cbemical invnntigations of tbia beautiful and numerous tribe of plants bave yet bem made. One or two of tbom bave been employed in medicine, and ipon tbesc a few imperfect analyses bavo been sketcbed out, wbicb I sball notice in tbis place. 1. AspUHum Jilex mas. Tbis fern Is tbe po/y/todium Jilex mas of LinnflE>us. Tbo root of it bas a bitter taste, and was employed as ;i medicine by tbe ancients ; for it is considered by botanists as tbe OjjXufl-Tif/f of Dioscorides,* tbe roots of wbicb, be says, possess tbe property of expelling tbo tape-worm. Tbouj^b recommended by some modern practitioners, it was little used till tbe Frencb govern- ment, in 1775, purciiased Madame Noufer's secret remedy for tbe tape-worm. Sbe was tbe widow of a Swiss surgeon, and ber remedy bad acquired great celebrity. It was tbr lowdered root of this plant. Tbe dried root is nearly witbout smell. Its taste is at first swoetisb, tben sligbtly bitter and astringent, and it is mucilaginous when cbewed. It varies mucb in its properties, according to tbe season of tbe year in wbicb it is taken up, and becomes inert if kept above two years. Tbe roots should he dug up in summer, when they bave a greenish colour and a nauseous smell, and do not change when tbey are dried in tbe air. They were analyzed by M. Morin, in IH'il.f According to bim, they owe tbeir antbelmintif proi)erty to an oily substance capable of being sapoi:ified. It bas a njiuseous odour, similar to tbat of tbo roots. Its taste is very disagreeable. It is heavier than water, when burnt emits a tbick smoke, and it nitiy be distilled over with water. Tbe roots contain, besides gallic and acetic acids, uncrys- tallizable sugar, tannin, starch, a gelatinous matter insoluble in water and alcohol (bassorin?), lignin, and some salts wbicb are found in tbe ashes. The oily matter may be obtained by tbe following process : — Di- gest tbe pounded root in ether, till that liquid will dissolve nothing more. Distil off the greatest part of tbe ether, and evaporate the last portions of the solution in an open vessel. The oil remains. It reddens vegetable blues, yields a little volatile oil when distilled with water, and when left at rest deposits stearin. It is partially soluble in alcohol, and the solution deposits crystals of stearin. To ■>\' \ i V i' 'i ■ ^ 1' i ii'-if * Lilj. iv. cap. 180. ■\ Anil, tic Cliiiii. I'l ilf I'livs. xxvi. 21!>. ;5 o 930 FERNS. Il .!< 1 1 ■ this oil M. Peschier ascribes the anthelmintic properties of the fern root.* 2. Aspidium coreacittm. This fern, which is a native of Peru, is called in that conntry cnlaguala. Tlie root of it was introduced into medicine as a cure for pleurisy, but it was not found to possess the properties ascribed to it. Vauquelin, who subjected it to ana- lysis, found it a very complex substance, and separated from it no ^wer than the foUowinjr substances : — Lignin Gutn Resin Sugar Starch Colouring matter Malic acid ? Muriate of potash Lime Silica. Alcohol dissolves the resin and sugar. By evaporating the solu- tion to dryness, and treating the residue with water, the sugar is separated and the resin left. This resin has a reddish-brown colour, and a bitter and acrid taste. It dissolves in alkalies, com- municating a brown colour and a bitter taste, and is again separ- ated by acids. Vauquelin suspects that this principle is the consti- tuent of the root, both of this plant and of the other filices which possess vermifuge properties. Water dissolved the gum and the muriate of potash, wliich were obtained by evaporation. Diluted nitric acid dissolved tlie starch and the colouring matter, and let fall the former when mixed with four times its bulk of alcohol. The woody fibre remained, which, when incinerated, left carbonate of lime, muriate of potash, and a little silica. As the decoction reddened vegetable blues, it is possible that the lime was in combin- ation with malic acid.f 3. Aspidium fragrans. This fern grows on the high rocks round the lake Baikal. It is called by the natives serlift, and is used by them as a substitute for tea. It is said to resemble very closely common green tea in its flavour.^ 4. Pvlypodium vidgare. The root of this fern, formerly used in medicine, was examined by M. Desfosses. He found it to con- tain a sweet-tasted substance, possessing the properties of sarcocd- lilt, mannite, incrystallizable sugar, starch, albumen, malic acid, lime, magnesia, and oxide of iron. § Viscin had been found in this root by M. Planche, in \8V2.\\ 5. Several of the equisetums have been subjected to a chemical analysis by M. Braconnot.^ They do not, strictly speaking, be- long to the tribe oi Jilices. I shall, notwithstanding, place them here, in order to avoid too many subdivisions. Eqiiisdiim ffiitiatilc, or riiur-liorse tail. This plant, which is so common in Great Britain, was found by Braconnot to contain • Jour, (le I'liiirmacio, xv. 292. t Aiiii. i\vx l'li,iiiiiiic'ie, ii. 'Mio, II .lour, (ie Piiuriiucie, xiv. UUG. •j- Vauquelin, Ann. fie Chim. Iv. 22. § .lour, de Fliarmacie, xiv. '276. Ann. lie (Jliiiii. et de Phys. xxxix. 1. FERNS. 1 Water . 2 Lignin . 3 Silica 4 Pectic acid 5 Sulphate of lime 6 Equisetate of magnesia 7 Sulphate of potash .... 8 Extractive, insoluble in alcohol 9 Chloride of potassium 10 Saccharine matter soluble in alcohol 1 1 Phosphate of lime, with a little iron . 12 Lime 13 Acetate of magnesia 14 Fatty matter, with chlorophylle 15 Animal matter, reddened by muriatic acid 16 Phosphate of potash 17 Oxalate of lime 18 Equisetate of lime 1 9 Equisetate of potash 20 Wax 21 Muriate of magnesia? 931 } 81-33 5-30 4-32 2-26 1-22 MO 1-02 1-00 0-98 0-86 0-20 0-16 0-14 0-08 0-02 0-01 traces 100-00 The equisetic acid, discovered by Braconnot in this equisetum, has been described in a preceding Chapter of this volume. EqiAsetum hyemale. This equisetum is also a native of Bri- tain, and is much employed in polishing, under the name of Dutch rushes. Braconnot examined the ashes of this species, and of three other species of the same genus. The following table exhibits the quantity of these ashes, and the constituents found in them : — Constituents, Ashes from 100 parts of the plant SB 5 Sulphate of potash. Chloride of potassium. "o Phosphate of lime, ferru. ginous. Equisetum ? fluviatile $ 23-61 12 3-39 2-83 2-72 1-46 0-66 0-55 1 Equisetum 1; , , q, hyemale S| 8-75 0-33 0-28 0-93 0-80 0-72 Equisetum arvense ] 13-84 15-50 6-38 0-37 0-22 5-51 0-46 not weighed 0-30 Equisetum limosum ; 6-50 '•' 2-20 1-20 1-50 0-30 ditto trace 1:1 'I il m M^ 932 LICHENS. CHAPTER XIV. OF LICHENS. , The lichens are a class of plants which differ almost in every respect from other vegetables. Many of them have not the smallest appear- ance of plants, but form hard crusts, which cover rocks, wood, trees, &c. ; others have the form of leaves or of branches, but nothing resembling flowers is visible. It was to Tournefort and Micheli that Botany is indebted for first fixing the word lichen, formerly vague and ill defined, to a ])eculiar set of plants. Afterwards Linnaeus placed them among the alga?, and described 81 species. Since that time a great variety of botanical writers have devoted considerable attention to them, particularly in ascertaining and de- scribing their parts of fructification, and the various changes which they undergo in the different periods of their vegetation ; but few only have attempted to analyze them, or to point out the useful pur- poses to which they may be applied. Willemet has given us an historical account of 4 1 species of lichens, and detailed their medical and economical uses with considerable accuracy. Amoreux, in a dissertation on the subject, has given us still more copious details, and has published likewise a brief cliemical analysis of some of tlic most remarkable lichens. Hoftmann, who had previously distin- guished himself by his botanical arrangement of the lichens, pub- lished an account of their chemical and economical jjroperties in 1787, and has given us the chemical analysis of several, made by Georgi with considerable care. VVestring turned his attention par- ticularly to the uses of the lichens in dyeing ; and in seven disser- tations, published successively in the Stochholm Transactions from 1792 to 1797, has examined almost all the lichens of the north, and described the colours which each of them is cai)able of yielding, and the manner of obtaining it. It is to these writers, and to Georgi, that we are indebted for the few facts known respecting the com- position and chemical properties of the lichens. The lichens are found in all countries and climates, and are very numerous ; considerably more than two hundred species have been described by botanists as natives of Britain. From the experiments of Georgi, professor of Chemistry in Peters- burgh, we learn that the ramalina farinacea, cetraria glauca, placodium physodes form with water a mucilage which yields, when evaporated, a gum as transparent and tasteless as gum arable. Lichen pulmonarius yields likewise a gum, but its taste is somewhat bitter. The gum yielded by these lichens amounted to ^th of their weight. When treated with alcohol, the liquid acquires a green colour and a bitter taste.* Amoreux, who repeated these experi- * See the ex|)erinionts of'Cjeorgi, as quoted by Amoreux, in his Researches' et Kxperiences sur les divers Lichens, p. 94. LICHENS. 933 I every respect nallest appear- [S, wood, trees, 3, but nothing t and Miclieli jc/tew, formerly }. Afterwards )ed 81 species. J have devoted taining and de- changes which tation ; but few ; the useful pur- as given us an ed their medical Amoreux, in a copious details, 1 of some of tlie i-eviously distin- le lichens, pub- al properties in jveral, made by is attention par- in seven disser- a7isa(tions from |f the north, and of yielding, and and to Georgi, feting the coni- es, and are very jcies have been listry in Peters- \etraria glauca, |ch yields, when IS gum arable. ste is somewhat to ^th of their Jquires a green these experi- his llescarclies et ments, obtained from the sticta pulmonaria, a reddish gum, much less transparent than gum arable. This lichen gave a yellow colour to alcohol. Probably he had examined a different species from that tried by Georgi, or if not, the lichens must have been of very dif- ferent ages. Amoreux found, that when the evernia pruuasfri was steeped in water, its branches became transparent like animal membrane, and ad- hered strongly to paper. In this state it is insipid, but as friable as celery. He obtained abundance of gum from the cetraria Islandica, and from all the broad-leaved lichens tried. He succeeded in extracting gum from the ramalina fraxinea, peltidea canina, and lichen coperatus of " innaeus. This last gave a lemon-yellow colour to ammonia.* eorgi found that when parmelia physodes, usnea plicata, ramalina jn nacea, and sticta pidmonaria were boiled in water, they yielded a yellowish mucilage nearly insii)id, and that the lichens thus treated might be eaten with salt. They all yielded a portion of resin to alcohol, but it did not give a taste to the water in which they were boiled. When incinerated, these lichens yielded a little potash, lime, and silica, but no sulphuric or muriatic salt. When distilled, they yielded an acidulous water, and a yellow or blackish oil which sunk in water. Such are the imperfect experiments hitherto made on the con- stituents of a few of the lichens. One of them, however, the cetraria Islandica, or Iceland moss, has been subjected to a rigorous and curious analysis by Berzelius. He obtained from 100 parts of this lichen the following constituents : — Syrup ..... Bitartrate of potash with some tar- trate of lime, and phosphate of lime ..... Bitter principle .... Green wax .... Gum ... Extractive colouring matter Starch ..... Starchy insoluble matter !<■' 3-6 1-9 3-0 1-6 3-7 7-0 44-6 36-6 1020i- Berzelius afterwards examined the tisnea plicata, usnea harhata, ramalina fastigiata, and the ramalina fraxinea. He found them all characterized by the presence of a species of starch which possesses several peculiar properties.^: I shall now mention such of the lichens as are most remarkable for the colouring matters which they yield. 1. Roccella tinctoria. This lichen, which grew abundantly in the Canary islands, but which is found also on the south coasts of England • See the experiments of Georgi, as quoted by Amoreux, in his Researches et Experiences sur les divers Lichens, p. 95. \ Ann. de Chim. xc. 277. % Afhandlingar, iii. 381. pi i5i*i!i^S •■' .^>l ; 'i 1 i iiii* 1 '!.. ■ 1 11 '■■ :ii ■ ) 934 LICHENS. and France, yields the dyestutF called archil, of which an account has been given in a preceding Chapter of this volume. 2. Lecanora pavlla. From this lichen, which grows abundantly in the mountains of Auvergne, and other parts of France, and which is common also in Britain, the pigment called archil of Auvergne is prepared. The process is pretty much the same as that by which the lichen roccella is prepared, and the pigment is distinguished by the same name, and applied to the same use, but is not considered as so valuable. It is obvious that the colouring matter of each is analogous. 3. Pertusaria communis. Treated with lime and sal ammoniac, it yielded a brown colouring matter to Westring. 4. Lecanora ventttosa. This lichen dyed wool of a brown colour which resisted the action of alkalies. 5. Lecanora hcematomma yielded a wax-yellow colour. 6. Isidium corralinum. This lichen was found by Westring to abound in colouring matter. By simple infusion in water, with a little common salt, it dyed wool yellow. Without addition, it gives a deep-brown of considerable permanence. It yielded the same colour when treated with sal ammoniac and lime. 7. Isidium IVestringii yielded a fine orange, which was brightened by muriate of cobalt. 8. Lecanora tartarea yielded a fine brown. 9. Lichen centrifugus, with fixed alkalies, yielded a fine wax- yellow ; with water, a brown ; with common salt and nitre, an orange. 10. Parmelia saxatilis. This lichen, with soda, yields a yellow; with lime and sal ammoniac, a nankeen ; and with muriate of soda and nitre, an orange. 11. Parmelia physodes, by the same reagents, yields various shades of yellow and brown ; lichen juniperinus, yellow and brown; lichen tenellus, yellow, olive, and reddish-brown ; lichen furfuracem, yellow and brown. The same colours were obtained from a con- siderable number of leafy lichens. So/orina crocea, with lime and sal ammoniac, gave out a red colour. Westring obtained several colours from other lichens ; and by mixing several of them together, he varied the shade, and produced a new set of colours, differing both in their intensity and fixity. But for the particulars of his numerous experimento, the reader is referred to his dissertations on the subject.* 12. Parmelia par ietina. This lichen, which, during the last French war, when the continent was nearly deprived of colonial produce, was recommended by Dr Sande as an excellent substitute for cinchona bark, has been subjected to a chemical analysis by M. Herberger.f He obtained * The first lias been translafed into French, and printed in vols. xv. and xvii. of the Annates de Chimie. The others are inserted in Crell's Annals for 1796, 1797, and 1799. t Jour. (le Pharm. xx. H^Q. LICHENS. Wax • • 1 Stearin crystals • ■ 0-5 Yellow colouring matter • • 3-5 Red colouring matter . • k 0-5 Gliadino • • 5-2 Chlorophylle • • 3-5 Bitter principle, &c. . • * 2-5 Soft resin . • • 3-5 Gum with starch • • 9-0 Extractive . • t 2-0 Ditto, dissolved by caustic potash 15-0 Lignin • • 46-0 Volatile oil » a trace Water « s 5-0 9Z5 97-2 The yellow colouring matter is in small yellow crystalline grains or plates, which acquired, when pulverized, a golden yellow colour. It is soluble in the volatile oils, and very soluble in alcohol and ether ; but it is insoluble in water. Ammonia and the fixed alka- line carbonates dissolve it partially. The addition of caustic potash gives it a red colour; and yellow lakes are obtained by adding acetate of lead or protochloride of tin. The alcoholic solution of this matter is coloured carmine red by caustic potash, aurora red by ammonia and the fixed alkaline car- bonates. These last occasion a precipitate of yellow resin. Dilute sulphuric acid, concentrated acetic and muriatic acids, nitric acid, acetate of lead and protochloride of tin, produce the same effect. When heated in a glass tube the yellow colouring matter gives out vapours not ammoniacal, at first yellow, and then red, which con- dense first in drops, and then adhere to the tube in a yellow powder or yellow crystals. Finally, an cmpyreumatic oil is disengaged, and charcoal remains. The red colouring matter was in very small red crystalline grains, having a carmine red colour. Soluble in alcohol, ether, volatile oils and hot water ; but not in cold water. The alkalies and con- centrated sulphuric acid deepen its colour. Dilute sulphuric acid, acetic acid, muriatic and nitric acids change its colour to yellow. Braconnot has ascertained that many of the lichens contain a great deal of oxalate of lime. He extracted it in abundance from variolaria communis; pertusaria communis; urceolaria scruposa; isidimn corrolimnn ; patellaria tartarea, ventosa rubra, hematomma; vaomi/ces ericetorum ; sqnammaria lentiyera, placodium radiosum, ochroleucum ; psora Candida. And he has shown that it may be extracted by mixing the powdered lichen wit'i about a third of its weight of concentrated sulphuric acid, diluting the mixture with water, and boiling it about half an hour. Then filtering and eva- porating very cautiously, the oxalic acid crystallizes.* * Ann. de Chim. etde Phys. xxviii. 320. H 1 «, I 111 I 1 ■ > f. ii 1 ii i ^ '■■ 1:1 Jfil^p ','■■'■ i m 936 MUSHROOMS. 'i CHAPTER XV. O V M U S II ROOM S. II. ''i- .1 r I The mushrooms are a class of plants proverbial for the rapidity of their growth and their speedy decay. When they putrefy, tiiey give out an extremely unpleasant odour, and appear to approach animal matter much more closely tlian other vegetable substances. They attracted the attention of M. Vauquelin and M. Braconnot, to wnom we are indebted for the analysis of no fewer than 1 7 species of this hitherto neglected tribe of vegetables. Braconnot has dis- tinguished the insoluble spongy portion which characterizes tlie mushrooms by the name offunfj/in, and under that name it has been described in a preceding Chapter. It a])proaches lignin in its pro- perties; but seems to be sufficiently distinguished from it by various characters, particularly by constituting a nourishing article of food, and by being much less soluble in alkaline leys. Braconnot like- wise ascertained tlie existence of two new acids in mushrooms. One of these has been described in a former part of this work under the name of holetic acid. The other, which appears to constitute a very general ingredient in mushrooms, he has on that account distin- guished by the name oifungic acid.* The following are the different species of mushroom hitherto sub- jected to analysis. 1. Agaricus campesf.ris. This argaric, which is a common article of food, was analyzed by M. Vauquelin, who found in it the follow- ing substances : — (1.) Adipocire. This substance was obtained by boiling in alcohol the matter that remained after the juice of the agaric was pressed out. The alcohol on cooling deposited the adipocire in flocks. It has a brownish-white colour, a fatty feel like that of spermaceti, melts when heated, and gives off a white vapour, having the odour of fat (2.) An oily or fatty matter (3.) Vegetable albumen (4.) The sugar of mushrooms (5.) An animal matter soluble in water and alcohol. When heated it gives out the smell of roasting meat. Similar to the substance called osmazome (6.) An animal substance insoluble in alcohol (7.i Fungin (8.) Acetate of potash .f • The name is unhappy, because, according to the received principle of naming acids, it indicates that the acid ro named is a compound o( funyin and oxygen; an opinion so far from being established tliat it has not even been advanced. f Ann. oms. One ic under the itute a very Dunt distin- itherto sub- imon article the follow- boiling in I agaric was Idipocire in like that of lour, having I'hen heated |e substance We of naming [and oxyytn; vanced. 2. Agaricus volvaceus. This agaric, according to the analysis of Braconnot, contains the following constituents : — (\.^ Much water (2.) Fungin (3.) Gelatin (4.) Vegetable albumen (5.) A great quantity of phosphate of potash (6.S Acetate of potash (7.) Sugar of mushrooms (8.) A fluid brown oil (9.) Adipocire (10.^ Wax (11.) A very fugaceous deleterious matter ()2.) An uncombined acid, suspected to be the acetic (13.) Benzoic acid (14.) Muriate of potash.* 3. Agaricus acris, or piperatus. This agaricus was examined by Dr Lister in 1672.t He obtained from it a milky juice with taste hotter than pepper, not discoloured by exposure to the air, nor by the blade of a knife. It speedily coagulated when kept in a glass vessel; but did not lose its hot taste. Trommsdorf made some ex- periments on it, and extracted from it a peculiar acrid matter and vegetable albumen. When distilled it yielded a considerable quantity of carbonate of ammonia.^ Braconnot subjected it tc an elaborate analysis, and extracted from it the following substances : — Water Fungin Vegetable albumen Gelatin Much adipocire Acetate of potash Sugar of mushrooms Phosphate of potash A peculiar vegetable acid united to potash An oily matter A very acrid and fugaceous matter Muriate of potash. § 4. Agaricus stypticus. Twenty parts of this agaric, analyzed by Braconnot, yielded Fungin ..... Resin 7 Adipocire ^ • • • • Unknown gelathtous substance Combustible acid united to potash A fugaceous acrid principle 16- 1- 1-5 * Ann. f the beauty and lys be referred to «TnUCTU»E OK P,.ANTS. Dr Stephen Hales nm. «<• .u ^^' m^ were nol n'Jr ' °P'"™» °" "'o ™biect of ^S '^''Penmenters mei DnlT 1 ?.^ correct. ""-"J"^" "' ^ne motion of the l)uhamel alone exeelSTo'^H'' '"^ ^''^ ^-^P-^-en s accurie an !' cr^wtVeT„S^,ettl,,!;r'"™»' *etch. n>a„, liters of & V.U uy jw. Jiieser, ni his f ; ■; I .0 1.1 HI 053 STnUCTUllE OF PLANTS. Ill Memoire aur F Organisation des Plantes, which pained the prize rospectinp tlie orjj^anization of jjlants, ottered hy the Teylerien Society, in the year 1812. The view of the phy8ioh)gy of plants contained in the same dissertation is also valuable, though not so full nor conijdete as that respectinjjf the anatomy. Let us now take ft view of the facts rcspectiiij; the structure of plants, whicii have been established by the dissections of them that have been made — observing', in setting out, that the subject is encompassed by almost insuperable difficulties. The organs of vegetables are so small, that in order to make them visible to thy eye, it is necessary to view them through a microscope magnifying several hundred times. This, of course, admits oidy a very small field, and the t)ptical deceptions, to which we are liable in such cases, are very apt to mislead. All plants seem to be comi)osed of cclh or vesicles, the walls of which are exceedingly thin and transparent. These cells are some- times round, nu)re frequently elongated, and not seldom hexagonal, on account of their mutually pressing against each other. In some cases the elongation is so great, as to give the cells the appearance of hexagonal colunuiS pointed at their upper and lower extremity. The position of the;-e columns is usually parallel to the axis of the stem ; though some of them are horizontal. When the cells press against each other, small intervals are left between them. These interstices form tubes called intercellular canals. They have no proper tunic, but only the walls of the cells. These intercellular canals are full of sap, and it is by them that the sap passes from the roots to the sunnnits of the plant. In some cases, these intercellular canals increase in size, so as to exceed the diameter of a cell at least ten times. Thus enlarged, they constitute what have been called the proper vessels of the plant. But these pro])er vessels do not differ, except in size, from the intercellular canals, and like them, have no other tunic than the walls of the cells. The size of the cells varies from O'OOG, to 0-0015 inch in diameter. A square inch of the leaf of the dianthus caryophyllus exhibits 3^ millions of such cells. In annual succulent plants they are larger than in shrubs and trees. Each cell has its own wall, so that where two meet the partition is doid)le. In the cellular tissue, small round globules occur. Those in the cells are transparent. They arc soluble in boiling water, and become starch. These small globules are suj)poscd to be intended for the formation of new cells, in Arder to increase the size of the plant. Very small green-coloured globules are also observed adhering to the walls of the cells. They constitute the green colouring matter of tlie plant, and are insoluble in water. The cells have no communication with each other; yet they seem to be pervious to moisture, but in what way it enters is not under- stood. There are three kinds of cells, which are distinguished hv their p(>sition. msB STnUCTURE OF PLANTS. 953 ned the prize the Teylericu logy of plants thoufj;h not so ,et us now take ts, whicn have D been made — isscd by almost e so small, that ry to view them mes. This, of iciil deceptions, mislead. es, the walls of 3 cells are somo- dom hexagonal, )ther. In some i the appearance ower extremity. ) the axis of the intervals are left .lied intercellular the walls of the ind it is by them jf the plant, in size, so as to Thus enlarged, i.se/.s' of the plant, size, from the tunic than the inch in diameter, yllus exhibits 3^; " they are larger dl, so that whore Those in the lling water, ami ll to be inteniled the size of the rved adhering to colouring matter ■; yet they seem trs is not inuler- listinguished by 1. Those of the bark and pith. They have the common c\\\\^- soidal form. y. The elongated cells of the liher and 7i'()otl. Tiicy eonstitute the interior part of the bark of jjlants having a hard pareni'hyma, and of trees, and constitute the basis of the wo 'v fibre. Hy age the cavities of these cells are obliterated. The. are intercellular canals both in the liber and wood. It is among the elongated cells that the peculiar vessels of milky and resinous plants are formed. 3. The cells of the viedullanj rays. What are called medullary rays, consist of parenchyma ))assing horizontally from tin; pith to the bark, through the wood. They consist of horizontal elon.'iatetl cells, the cavities of which are obliterated by age. They have in- icrcellular canals. The pnrcs are obrKjue openings or slits in the epidermis, so small that in the epidermis of the kidney-bean, a s(puu'e inch contains more than 300,000 pores. They are situated on the cpidcruiis of tlie soft part of the plant, and are found chicily on the under side of the leaves. They are surrounded by a very mimite vessel, Ibrui- iiig a net-work on the epidermis. Spiral vessels exist also in the more perfect ])lants. They are composed of a fibre, twisted like a cork screw round an empty sj)ace. All the turns of the screw are contiguous and joined, so as to form a tube much larger than any of the intercelluhir canals. These vessels never occur in the bark or pith, but only in the wood. They occur in bundles, containing al)ont thirty spiral ve.-seis. A now bundle is formed every year on the outside of the old, consti- tuting the annual layer of wood formed in every tree. The spiral vessels are divided into simple, annular, duikd, rami- fied, rcticulalcd, and in rosaries. The simple consist of one or more fibres twisted round an empty space, so as to form a round tube. I'liey have never any nu'uibrane between the turns of the fibre, and the fibres are not always close. They occur in all young plants, and are the only spiral vessels in bundles near the pith. The anmdar are round tubes formed of rings soldered together. In herbaceous plants, they occupy the same place as the simple, viz., near the pith. The rings are often at some distance from each otlior, the interval being filled up by a membrane. The dotted spiral vessels are formed by one or more fibres a little Hattened, which, twisting like a cork-screw round an empty space, leave interstices between the spirals. These interstices are tilled up hy a membrane more or less thick and transparent, in which are small elliptic points, sometimes dark, sometimes transparent. Hence in them the spirals are always at a distance from each other. The simple or annular spiral tubes are converted into the dotted as the ago of the })lant advances. They always exist in the alburnum. Tlioy are much larger than the simple spiral tubes, and are some- times visible to the naked eye. The spiral fibre is either simple or aniudar, and when two dotted vessels are contiguous, pne membrane U ,! lis 904 STIIUCTUIIK Oi- PLANTS. 11 Iri ?') at the plnco of contact serves both. The nature of the elliptical dots is unknown : they do not seem to be pores or slits. When the spirals separate to a greater distance from each other, and, uniting from space to space, lill tiie interstices left among them more or less completely, by new branches of the original spiral ves- sels, they constitute what have been called ramifying and reticulated vessels. Such vessels have been observed only in a small number of plants. The vessels in rosaries, as they have been called by M. Mirbel, who first observed them, occur only in the knots of the stem and in tuberculous roots. They are just the simple spiral vessels, with their diameters diminished from space to space, so as to give them the appearance of a string of beads. The spiral vossels do not occur in the acotyledinous plants, ex- cept in the eqnisetacea; and fans, and in them only in small quanti- ties. Till the spiral vessels aj)pear, there is no pith, no elongated cells, no bark nor wood. In the monocotyledinous plants, the bun- dles of spiral vessels have no iixed place, but are dispersed through the whole extent of the stem. These plants have neither pith, nor liber, nor bark, nor medullary rays, vuv wood. In the grasses, the centre of the stem is often hollow, and the bundles of spiral vessoU are dispersed round that cavity, but not regularly. In dieotyledinous plants, all the pnvts of the vegetable are deve- loped. In the herbaceous division, the bundles of spiral vessels form one or more circles round the pith. These bundles are always surrounded by elongated cells. The spiral vessels never immedi- ately touch the connnon cells, but are separated by elongated celU. From Kieser's observaiions it seems ])robable, that the number of spiral vessels thus surrcniding the pith, correspond witli that of the stamina of the flower. The u'ood is formed of a circle of bundles of spiral tubes, sur- rounded by elongated cells. Every year a new circle is formed round the former, so that there are as many circles of wood as tlie tree has lived yeavs. Duhamel has shown, that a layer of liber is also formed every year, in contact with the new layer of wood. In spring, u mucilaginous li(iuid, called camhiwn, is interposed between the liber and wood. From this cambium the new layers of wood and of liber are formed. The wood at first is soft, and its spiral vessels transparent. It is then called alburnum. This alburnum, by the compres-^ion and final shutting up of the spiral vessels, &c., is gradually ( )nverted into perfect wood. Various opinions have been formed respecting the uses of the spiral vessels. Some have supposed them sap vessels, others that they ore analogous to the nerves of animals. Ihit the weight of evidence seems to be on the side of those who, with Grew and Mal- pighi, consider them as air vessels. The epidermis is the very thin membrane which envelopes tiie soft parts of plants, where there is parenchyma, as the leaves. It TICMl'Kn.VTUnK OK I'l.ASTJl. 9(>r> f the o\lii)tical it8. om each other, .ft among them riiml spiral ves- I unci reticulated II snirtll nuinher I hy M. Mirhel, the stem and in ral vessels, with as to give them inous plants, ex- in small quant i- ith, no elongated ! plants, the hun- .isperscd through neither pith, i»"" 1 the grasses, the 5 of spiral vessoU jgetahle are devo- "of spiral vessels l)undles are always ^Is never imtnedi- y elongated cells. lat the nuuiher of id with that of the spiral tuhes, sur- circlc is formed js of wood as the ormed every year, , a mucilaginous liber and wood. liber are formed, ansparent. It is compres-^ion and [adually * inverted _. the uses of tlie \essels, others that |3ut the weight of lb Grew and Mal- iich envelopes tlie IS the leaves, 1' is only wanting in tlie bark of trees, and in tlie itlOTP imperftv plants composed of tul)o.s. Porcn are very snmll openings on the ei)ldermis, round or ovai, surrounded by an elevation and by an area tilled with very fine v^ji- sels, communicating with the vessels of the epidermis. The dia- meter of the vessels of the epidermis does not exceed j j^no^h of an inch. They form a net-work on the surface of the leaf, and termi- nate in the cells surrounding the spiral vessels. They probably communicate with the intercellular tubes. Hairs consist of a row of cells arranged in a line. They arc sometimes straight, sometimes pointed, and sometimes ramified. CHAPTER II. o V r II E r E M p E 11 A r u ii e o r i' l a n t s. It has long been a question among vegotcable ])hysiologists, whether plants, like animals, have the power of generating heat ? This question has not hitherto been answered in a satisfactory manner. There can be no doubt that there is a particular tenq)erature which suits best with every plant, and this temperature is connected with the climate to which the plant is suited. In this country, and in- deed in all temperate climates, the ditlerence between the tempera- ture of the an' at sunrise, when it is coldest, and about two hours after noon, when it is hottest, is very considerable. Now, wood being a bad conductor of heat, it is probable that, if a thermometer were jdunged into the centre of a tree, we should find its tempera- ture higher than that of the air at sun-rise, and lower than that of tlie air at two hours after noon. Mr John Hunter bored a hole in a walnut-tree, 5 feet above the surface of the ground. The tree was 7 feet in circumference, the hole was 1 1 inches deep, and the bulb of a thermometer was plunged to the bottom of it. On the 29th of March, 178G, the temperature of the atmosphere, at 6 in the morning, was 57°^, while that of the tree was 55°. April 4th, at 5 in the evening, atmosphere 62°, tree 56°. April 5th, at 6 in the evening, atmosphere 47°, tree 55°. April 7, 3 afternoon, atmosphere 42°, tree 42°. Ajn-il y, (a cold day, with snow, hail, and wind,) at 6 in the evening, atmosphere 3'J°, tree 45°. In October, when the tree had ceased vegetating, he generally found its t(niiperature warmer than the atmosphere. But in the winter of 1786, which was very cold, he found that the temperature of the tree gradually sunk as low as that of the .air, which was ♦ .'11^ ii\-\ .A DftO TKMrunATUUB or PLANTS. I> ( sometimes an low as 17". Yot the anp, t.liou«,'li its freezing point is as lii^^li us 32°, «li. Aa the tree is hotter than the air at sunrise, and colder at 2 p.m., it is obvious that there nuist be a point between these two extrenu^s, at which the temperature of the centre of the tree and of the air must bo e([ual. Dirteretil trees exhibit little difference of temperature, providcul t le sizes be ecpial, and the position of the thermonu'ter in each similar. The cold to which the interior part of a tree may be reduced without injury, is v(>ry considerable. In the winter ot 182(), Schii- hler observed, that tlie temperature of several trees which he ex- amined, was as low as Qo-.O ; yet the sap did not freeze, nor was the vegetation of the trees injnriid. The trees upon which these obser- vitions were made, were elms and red pines. These observations seem to leave little doubt that trees do not jmssess any means of generating heat, at least in any sensible (pum- tity ; but that their temperature depends u}»on that of the atmo- sphere in which they vegetate. Ihit it seems e(pially evident, that the living plant possesses the power of preventing the freezing of its sap, though cooled down far below the degree at which this freezing would take place in the dead plant. Of the naturt> of this power we possess no conception ; but it is obviously connected with the vitality of the plant. There cannot be a doubt, however, that in certain circumstances, plants are capable of generating very considt'rable quantities of lieat. Hubert observed, that the stamina of the (irnm cofdi/olimn, at the moment they shed their pollen, produce so nuich heat, that twelve of them, placed round the bulb of a thermometer, raised it from 79° to 143°. The observation was repeated several times with the same result.* Sencbier observed, that the stamina of the anon macnhitum, nnder the same circumstances, were 15°*75 hotter than the surrounding atmosphere. Dr Schultz of Berlin, on the Ist of May, 18.'33, when the thermometer stood at 0I°*25, apj)lied a thermometer to the flowers of the caladium phmdtijidum, which was emitting a disagreeable annnoniacal smell. It gradually rose to81°.t Saussurc examined the flowers of a great many plants, at the time of the bursting of the pollen, and only found a sensible quan- tity of heat evolved in three of them. 1. The stamina of the cucur- hita melo-pepo were from {"'S to 3°*G hotter than the air. 2. Those of the biynonia radicnns were froii 0°'<) to 3" ; those oi i\\G polyan- tlies tuherosa about 0°*C) hotter than the air.t These evolutions of heat have been shown by Saussure to bo the cotisecpience of the great (luantity of oxygen absorbed by the sexual organs of the plants at the instant of fecundation. The stamina of * Jour, do Pliys. lix. "JSl. t Jour, ilc Pharuiucio, xx. 1 IG. \ Ann. tlo Cliiin. ct do Pliys. xxi. '119, , I 958 TEMPERATUnE OF PLANTS. i i I the arum maculatuin, for example, absorb 200 times their bulk of oxygen gas, and convert it into carbonic acid. The following table exhibits the volumes of oxygen gas absorbed by 1 volume of the flowers and leaves of various })lants, as determined by Saus- sure: — * Oxygen absorbed. Hy the flowers. Ily the leaves. 11 4 7-7 9 3 ! 7-4 8-5 8-3 7-25 9 5 18-5 5-25 8-8 7-3 8-7 5-1 7-5 7-5 12 G-7 , 3-5 1 5 2-5 9-8 4-25 1 9-1 8-1 ' Cheiranthus incanus — 6 p.m. Ditto, double . Polyanthes tuberosa — 9 a.m. Ditto, double . Tropa!olum majus — 9 a.m. . Ditto, double . Datura arborea — 10 a.m. Passiflora serratifolia — 8 a.m. Daucus carota — 6 p.m. Hebiscus speciosus — 7 a.m. . Hypericum calicinum — 8 a.m. Cucurbita melo-pepo, male flowers — 7 a.m. Ditto, female flowers — 7 a.m. Lilium candidura — II a.m. Typha latifolia — 9 a.m. Fagus castanea — 4 p.m. From these ftvcts it is evident, that plants sometimes generate heat as well as animals ; and, from Saussure's observations, it fol- lows, that the process in plants is similar to that in animals, namely, absorbing oxygen gas and converting it into carbonic acid. Doubt- less the organs by which these changes are eflected in ])lants, are similar to those that perform the same process in animals, though the texture in the former is so exceedingly minute, that it is impos- sible to ascertain that similarity by observation. There can be no doubt that a certain temperature is necessary for every plant, to enable it to produce flowers and fruits. As this temperature depends in a great measure upon the climate, the con- sequence is, that certain plants, according to the temperature at which they blossom, are suited to particular climates, in which alone they vegetate in perfection. The following table, drawn up by M. Schiibler from a set of ol)servations made by him at Tiibingen on the Necker, in north latitude 48° 26', exhibits the temperature of the plants and of the air, at the time of flowering, of a considerable number of plants : — f • Ann. de Chim. et de Pliys. xxi. 283. f PoggendorPs Annalen, x. 592. TEaiPERATUUE OF PLANTS. 959 leir bulk of lowing table ,lume of the 1 by Saus- 311 absorbed. Hy the leaves. 4 3 8-3 !o 5 > 5-25 ^ 7-3 7 5-1 5 7-5 G-7 5 2-5 8 4-25 •1 8-1 itimes generate rvations, it fol- nimals, namely, ! acid. Doubt- l in plants, are nimals, though hat it is impos- Lre is necessary fruits. As this [imate, the con- Itemperature at 'l in which aloue irawn up by M. It Tubingen on Itemperature of a considerable Innalcn, x. 592. PLANTS. i 1 Day of 18;>,'). 1 March 28. TEMPEUATURE AT SUN.KISE TEMPERATUIIE AT TWO P. M. Mean temp, of the 6 preceding days. Mean temp, from 2jth March to the date in table. Of the air. Of the plant. Of the air. Of the plant. Uipline Mczeriuni.T Viola oderata, ^ blossom. Lcucojum verniim.J 27"-.'> 31"-775 56"'75 63"-375 43"-025 38-37 Ribcs Rrossularial , , , . et nibrum j '" """• Scilla bllolia, blussoms. April ! 3. 28"'62.5 31''-875 .'J0"-4a 47"-75 48"'575 40"-3 S,imbucii8 nigra, ") racemosa.f . , , Loniceratartarica, ('""''"• rilK's nigrum 3 Ulmiis campcstrisl ,,,„,.„„ popiilus tremula, j "'f»«'«"- 1 ! Pinus larix, T |,runus padiis, f , , - I/inicera Xylostcum.t '" "'"'• corvlus avellana. 3 Pufmonaria officinalis,? |,i,,„nm Anemone nemorosa, j "'"saoi" 1 April JO. 1 29"-75 34'-47fl i 64°-625 60'"125 44"-825 4r'675 April 16. 35"'375 31-55 62"-375 59" 53"-376 44" -1 Eiionymus Europaiiif, 1 viburnum nptilus, 1 bprbcris vulgaris, Vin leaf. i^sculus hippncastanum, salix fragilis, J April 1 17. a I"' 125 r)2''-25 53"-825 52"'7 1 53-a 440-28 Pinus larix, I ,,. „ i salix fragili.sj'^"'^''""' 1 April 18. April 21. 27''-5 32" 41<'-45 38"-07r- 1 53"'6 44»-55 Carpinus betiiUis in leaf. Buxus sempervircns.l ,,,„.. tibca alpinum, ' j blossom. ze'-^i 34<'-7 59" 66"-975' 1 42"35 43"-79 1 Pyrus communis, 7 . , „. iprui,usd()mestica,j'"'^''f- 1 .\lnus glutinosa, blossoms. April 24. 52''-7 54"-5 1 7r-376 70"-25 45»-05 44°-31 Acer pseudo platinHs,") ■„ ,^.f vilis vinifera, j '" '"'• Ribes rubrum, 1 ki„,.„«, :cardaminepratensis,jblos»om. April 25. 47" 47"-75 67"-325 65" -75 43"-55 44"-78 Fagus sylvatica,] . , . ater campcstre j '" '^^'• April 2C. 51"-125 32"-25 72"-95 69»-125 53°-6 450-12 Tilia europaia, 7 . , , sorbus aucuparia, j '" "^'"' Acer platanoides.l , , prunua padus. j blossom. April 29. 43"-7 45"-5 71" 375 — 60''-35 46"-35 I'Imus campestris, 1 . , - ihamnus catliarticus,J '" """■ Prunuscerasus et avium, blossom April 30. 51"'-675 53"6 68"'45 63°-05 59''-675 46"-625 i Rhamnus fragila, 1 .„ .. populus alba et itallca,J '" '™'- May 1. 44<'-375 — 66"-873 65"'3 60"-125 46»-94 Pyrus communis, - 1 teulaalba, ;■ blossom. >:ambucu8 racemosa,.i May 2. 44"*825 47''-52r' 70°-25 68°*125 60»-57a 470., 4 ■ Quercus robur, 7 'hustyphinum.J'in leaf. Juglans rcgia. 3 May 4. 36""5 380-975 72°-5 69<"575 56°-97£ 47"*5 : Robinla ))scudacacea, in leaf May a. 43"-25 45-95 78"-125 74"'075 56°-75 47"-66 Robinia inermis et liispida, do. Acer campeslre, 7 ,,,„ ,„™ 'irburnum lant!ina,j '''''*''""• May 6. 46"-4 50" 83"- 7 5 790.7 56"-75 47°-93 f'axinus excelsior, in leaf. Junipcrus commiinis, blossom. May 8 1 .57»-2 — 6H"-45 -- 60''-02.' ) 48-67 il . 1 I '■'. I !l I .1 l« i:-: I u5 I , l< ■ti !l 9G0 TEMPEII.VTUIIE Ol' PLANTS. Jit I'LANTS. D.iy of IS-.'.'^i. TEMPEItATURE SUN.mSE. TEMPERATUltE AT TWO P. M. II a? Of the ait. Of the plant. 60° Of the air. Of the plant. Pyrus inaliis, 7 i,|,,g.„™ acer |iseu.25 51°-126 1 49'-5 1 Viburnum opiilus,7 i,i„.„„ seoalecereale, 'j ''•"'»°"'- 48"-8"5 52"-25 65"-75 63"-5 1 i6l"-025 50" 1 ; Lonicera caprifolium, 7 bios- horjcunivulffarehybcrnunr.j som. Juiiu 1. 48'-875J 49"-65 64''-5 63" -3 7 6 51"-125 50"-22,) Vitis vinifcra, f tubus frnticosa, |'blojsom. sainbucus nigra, j Juiiu 15. 54"-5 57" 825 74"-75 71"'825 66"-975 5I„-0I Rosa canina, 7 bios, tiiticuin spelta hybcrnum,J som. June 20. July 1. 40''325 r.. 74"-76 71"-825 58"-56 5l"-s; Tamarix Ciermanica.T hordunm disticbiini ^blosiom. a;stivum, J 52"-7 — 76" 71 "-825 59"- 9 52 ■;)4 Tilia Europica, f acorus calamus, \ ■ blossom. avena sativa, 3 July lo'. July 20. July 26. Aug. 1. 54"*5 67"-826 70"-25 67"-325 59"-225 5;!"-|:5 Linum nsitatissimum,'^ spiraia ulmaria, Clilossom 6ol.ii.um lulwrnsum, ?"'°«som. mclilotus officinalis J Hottest day. 53-625 .56"- 7 6 87"-125 83"-75 68 -46 54"-l(i Harvest of tritium Sjielta begins. Atropa belladonna, blossoms. 54"-5 — C8» — 60"'675 54"-a4 Panicum milium, T vicia faba, -blossom. portulaca oleracca, J 61»-25 64°-625 77" 74"-075 60"'125 54"'8I Tanacctum vulgaro, / coriandrum sativum, r blossom, phaieolus vulgaris, ■' Aug. 12. 46'-625 — 62"375 61"-26 6P-476 5j"'aii ■Vonitum napcllus,7 ^^„,,„^, nicotiaiia rustica, J ">"-'">" Aug. 16. 5V625' 56"-75 61"'23 60"-576 58"- 1 5j"'0J Datura stramonium, T centauria beiiedicta, (,,,,.„ cicer arietinum, ^l'l"ssom artcmisia dracunculus, j Sep. 1. 42"-125 44"'825 i 69"- 125 65"'75 j 1 67"-325 5G"-4 1 1 Aster Chincnsi--, j dahlia pinnata, J -blossom. polygmmm (iri5 Gl"-925 48'"9n 65" i)25 49"-l 570.875 49"T)7 5jo.,25 49"5 Gl"-025 50" 375 5r-125 50"-22o 58""5a ! 59"-9 o2 ■;-i4 •325 59"-225 ftlVi:! .70 CS -45 r,4-U! 60"-57iJ 54"-o4 075 60°'125 •'■'•l'"^' 25 6r-475 5J"'oii 575! 58"'l 5a"GJ 07 ''325 5U"4 61" -7 , »•'"■•' It appears from the experiments of Edwards and Colin, that wheat, oats, and barley, are incapable of vegetating in a tempera- ture of 113°, and that they do not thrive in any country whose mean temperature exceeds 65°.* CHAPTER III. OF GERMINATION. I. Natural historians have proved, by a very complete induction of facts, that all plants arise from seeds. The pretended exceptions have disappeared, one after another, as our knowledge of vegetables increased : and now there remains scarcely a single objection en- titled to the smallest regard. The attempt of Girtannerf to revive the doctrine of equivocal generation, deserves no attention what- ever ; because his conclusions are absolutely incompatible with the experiments of Mr Sennebier upon the very substance on which his theory is founded. A seed consists of three parts ; namely, the cotyledons, the radi- cle, and the plumula, which are usually enclosed in a cover. If we take a garden bean, we may per 'eive each of these three parts with great ease ; for this seed is of so large a size, that all its organs are exceedingly distinct. When we strip off the external coats of the bean, which are two, and of different degrees of thickness in different parts, we find that it easily divides in- to two lobes, pretty nearly of the same size and figure. Each of these lobes is called a cotyledon {Jig. a.) The cotyledons of the bean, then, are two in number. Near that part of the lobes which is contiguous to what is called the eye of the bean, there is a small round white body (6), which comes out betweeii the two lobes. This body is called the radicle. Attached to the radicle there is another small round body (c), which lies between the cotyledons, and wholly within them, so that it cannot be seen till they are separated from each other. This body is called the plumula. The appearance and shape of these three parts vary much in different seeds, but there is no seed which wants them. The figure and size of the seed depend chiefly upon the cotyledons. This is evidenlly the case with the bean, and it is so with all other seeds. The number of cotyledons is different in different seeds. Some seeds have only one cotyledon, as the seeds of wheat, oats, barley, * Jour, d« Pharmacie, xxii. 210. 3q f Ann. de Chim. xxxiv. 85. M'm] r.; ,H >9I L 962 GERMINATION. and the whole tribe of grasses ; but most seeds, like the beau, iiave two cotyledons. 2. When a seed is placed in a situation favourable to vegetation, it very soon changes its appearance. The radicle is converted into a root, and sinks into the earth, the pluraula on the other hand, rises above the earth, and becomes the trunk or stem. When these changes take place, the seed is said to germinate : the process itself has been called germination. Seeds do not germinate equally and indiflPerently in all places and seasons. Germination, therefore, is a process which does not depend upon the seed alone ; something external must also affect it. 3. It is a well known fact, that seeds will not germinate unless moisture have access to them ; for seeds, if they are kept perfectly dry, never vegetate at all, and yet their power of vegetation is not destroyed. Water, then, is essential to germination. Too much water, however, is no less prejudicial to most seeds than none at all. The seeds of water plants, indeed germinate and vegetate extremely well in water; but most other seeds, if they are kept in water beyond a certain time, are rotted and destroyed altogether. 4. It is well known also, that seeds will not genninate, even though supplied with water, provided the temperature be below a certain degree. No seed, for instance, on which the experiment has been tried, can be made to vegetate at or below the freezing point : yet this degree of cold does not injure the vegetating power of seeds ; for many seeds will vegetate as well as ever after having been frozen, or after having been kept in frozen water. We may conclude, then, that a certain degree of heat is necessai'y for tlie germination of seeds : and every species of plant seems to have a degree peculiar to itself, at which its seeds begin to germinate ; for every seed has a peculiar season[at which it begins to germinate, and this season varies with the temperature of the air. Mr Adanson found that seeds, when sown at the same time in France and in Senegal, always appeared sooner above ground in the latter country, where the climate is hotter than in France.* 5. Seeds, although supplied with moisture and placed in a proper temperature, will not germinate, provided atmospherical air be com- pletely excluded from them. Mr Ray found that grains of lettuce did not germinate in the vacuum of an air-pump, but they began to grow as soon as air was admitted to them.t Romberg made ;i number of experiments on the same subject, which were publislicd in the ][^emoirs of the French Academy for the year 1G93. He found, that the greater number of seeds which he tried refused to vegetate in the vacuum of an air-pump. Some, however, did ger- minate : but Boyle, Muschenbroek, and Boerhaave, who made ex- periments on the same subject in succession, proved beyond a doubt that no plant vegetates in the vacuum of an air pump ; and that in those cases in wliich Hornbcrg's seeds gcrtninated, the vacuum wa? • Encyc. Method. Pliysio). Voyct. \2i. t Pliil. Trans. No. liii. like the bean, iiavc GKllAIlNATION. at ffrains of lettuce d, tlie vacuum was 11. Trans. No. liii. 963 far from norrppf « • ^^^ It follows thSo?e^S'^^ '^ t «^'" ^^''naining in the ro..' It 18 for this reason that seed. I'r' P''«P«''ties, have access oi" -d will gcU:n'„t ^•■^^""'"ation'of X'eod STaS gas, unless ,|,c8„ g„sea comin , T'''°S'=" ?«. or Mrbonic IS cxjieriments have been ^^!^!: ^ ."""'"rc of oxy.re„ „ '.?,,'"-"' '"-•en long kept, and whicl * h,^ 7''f ^«^^^''«^ seeds 4ich had grew readilv who., f-o V i • J^" constant y refusprl f« • " 6' Lio^ f ] '^^^^'^ ^^^tl' it-t g-erminate, BY vt sari S » "f"-— "• '"the light than from those fn^/if '?"'^' ^^^t^^' ^'-om the see ! .^vhen precautions werrtaken 1 l '.u^^^^'^ ^"^ he affinneS ?lnV -;he sun germinated sooner tha'^tl^e' "'if 'T^'y -«^« those JWr Sennebier reneafpl h:.f °^^ '" the shade II T?nf , i p-iwe P-cautrto^ntX^iir;;?'"^"^^' -dt 4d J ;" e constantly found the seeds In J "f T'^^'^^'^ in both st nations .t''.ose ,n the light.f We m-,v . I'^l'"'^"^ germinate sooner tS .;! ) •}>} fh "■ if!' J t <*j J !* l''in'yr, i\ri''!i(„|. \',.,,„t, I ■-'',), r'?4 GERMINATION. M injurious in consequence of the heat which it produces ; for when the direct rays of the sun were intercepted, thoufrh light was ad- mitted, the germination of the seeds was not sensibly retarded.* 7. Thus we have seen that seeds will not germinate unless moisture, heat, and oxygen be present. Now, in what manner do these substances afloct the seed ? VVhat are the changes which they produce ? It was observed before, that all seeds have one or more cotyle- dons. These cotyledons contain a quantity of farinaceous matter, laid up on purpose to supply the embryo plant with food as soon as it begins to require it.f This food, however, must undergo some previous preparation before it can be applied by the plant to the formation or completion of its organs. It is probable that all the phenomena of germination, which we can perceive, consist in the chemical changes which are produced in that food, and the conse- quent development of the organs of the plant. When a seed is placed in favourable circumstances, it gradually imbibes moisture, and very soon after emits a quantity of carbonic acid gas, even though no oxygen gas be present.^ If no oxygen gas be present, the ])rocess stops here, and no germination takes place ; but if oxygen gas be present, a portion of it is converted into carbonic acid gas. From the experiments of Saussure, it appears, that if seeds be left to germinate in a determinate portion of oxygen gas or common air, the bulk of that gas is not altered ; the carbonic acid formed being equal to the oxygen which has dis- appeared. Hence it follows, that the carbonic acid contains in it exactly the whole oxygen consumed. § No oxygen, then, is absorbed by the seed ; or at least, if it be absorbed, none of it is retained, the whole being thrown out in combination with carbon. The quantity of oxygen thus changed into carbonic acid by the germina- tion of seeds, is in some measure proportional to the weight of the seed : but some seeds require more than others. In the experi- ments of Saussure, wheat and barley, weight for weight, consumed less oxygen than peas ; while peas consumed less than beans and kidney-beans. The oxygen consumed by wheat and barley amounts to between yij'ooth and jooo^h of their weight; while that consumed by beans and kidney-beans may amount to tan^h part of their weight. II Similar experiments were made by Dr Woodhouse.^ From the observation of M. T. de Saussure, it appears that during the first stage of germination, the carbonic acid evolved exceeds the bulk of the oxygen absorbed, but afterwards the oxygen absorbed exceeds the bulk of the carbonic acid evolved. Azotic gas he found was always absorbed during germination in air, but * Rccbeiciics Cliimiqiies sur la Vesretation, p. 23. f In some seeds, us wheat, the food is laid up not in the coljledon but in tlie albumen of the seed. X Gougli, Manch. Mem. iv. •i\5. Cruickshank, Rollo on Diabetes, p. 452. § Jour, de Pliys. xlix. 02. || Recherche?, p. 13. ^ He tried the seeds of tlie zea mays, apium potroseiinum, iactuca sativa, cucur- bita citruiia, phaseoius salivus, sisymbrium sativum, raphunus sativa. Tliev changed oxygen into carbonic acid. Nicholson's Jour. ii. l(il. GERMINATION. 965 not durinir irerminnHr.r. • ^^^ " uoes not apnear Hi..f process of germination, a easTur/"' '"^ ^'««»'"Posed durin^ the Ne.ther hydrogen no; oxygen „'! "'" "" ^"^''^'''"'^^ that his so surprismo- if a nn-n^ r •'* " 8^'^^ 'i''e em ttprl r* ""' " 's so. together (when fli-Iori ?ii , ''*^^e been. Thim ?•? '*"^^^^'ff'it five times their wei^i:.'/^:) "?'o-l.od 200 gral \yllT\V'^'\'l! over merr..rvV f "^ ^'^ter in a vessel f«m IJ • " ^^-'^^ "''th verted i„,„sacS,ar„;™ or "r'"°', "'"'='' "'"J' »™tin is c""" 1 4 nefl,"" 'Tf ''"•I "'at old l,r'e- 1'! T'""' '» " P^'ial • Memoires de la Socie*^ Pi. • ^ destroyed. II II f ■ ""'I It « J ih ' 966 GEniSIlNATlON. I ' Hut when the farina in the seeds of vege- tables is converted into sugar, a number of vessels make their appearance in the coty- ledon. The reader will have a pretty dis- tinct notion of their distribution by inspect- ing the figure. These vessels may indeed be detected in many seeds before germination commences, but they become much more distinct after it has made some progress. Branches from them have been demonstrated by Grew, Malpighi, and Hedwig, passing into the radicle, and distributed through every part of it. These evidently carry the nourishment prepared in the cotyledons to the radicle ; for if the cotyledons be cut off, even after the processes above described arc completed, germination, as Bonnet and Sennebier ascertained by experiment, immediately stops. The food therefore is conveyed from the cotyledons into the radicle ; the radicle increases in size, assumes the form of a root, ginks down into the earth, and soon becomes capable of extracting the nourishment necessary for the future growth of the plant. Even at this period, after the radicle has become a perfect root, the plant, as Sennebier ascertained by experiment ceases to vegetate if the cotyledons be cut off. They are still, then, absolutely neces- sary for the vegetation of the plant. The cotyledons now assume the appearance of leaves, and appear above the ground, forming what are called the seminal leaves of the plant. After this the plunmla gradually increases in size, rises out of the earth, and expands itself into branches and leaves. The seminal leaves, soon after this, decay and drop off, and the plant carries on all the processes of vegetation without their assistance. As it does not appear that there is any communication between the cotyledons and the plumula, it must follow that the nourishment passes into the plumula from the radicle ; and accordingly we see that the plumula does not begin to vegetate till the radicle has mfido some progress. Since the plant ceases to vegetate, even after the radicle has been converted into a root, if the cotyledons be removed before the plumula is developed, it follows that the radicle is in- sufficient of itself to carry on the processes of vegetation, and that the cotyledons still continue to perform a part. Now we have seen already what that part is ; they prepare ^oorf for the nourishment of the plant. The root, then, is of itself insufficient for this purpose. When the cotyledons assume the form of seminal leaves, it is evident that the nourishment which was originally laid up in them for the support of the embryo plant is exhausted, yet they still continue as necessary as ever. They must therefore receive the nourishment which is imbibed by the root ; they must produce some changes on it, render it suitable for the purposes of vegetation, and then send it back again to be transmitted to the plumula. After the plumula has acquired a certain size, which must be at least a line, if the cotyledons be cut off, the plant as Mr Bonniil FOOD OF PLANTS. 967 :}rcw, Malpiglii, 13(1 through every ; prepared in the be cut off, even , germination, as 3nt, immediately )tyledons into the e form of a root, iblc of extracting ii\\ of the plant. ;e a perfect root, ceases to vegetate absolutely neccs- leaves, and appear minal leaves of the s in size, rises out and leaves. The off, and the plant t their assistance, mication between it the nourishmetit icordinglv we see . radicle has made ite, even after the ledons be removed the radicle is in- etation, and that Jow we have seen le nourishment of for this purpose, saves, it is evident in them for the [y still continue as the nourishment some changes on ,n, and then send (which must be at Int as? Mr l^onnd | ascertained by a number of experiments, afterwards repeated with cciual success by Mr Sennebier, does not cease to vegetate, but it continues always a mere pigmy : its size, when compared with that of a plant whose cotyledons are allowed to remain, being only as 2 to 7.* When the plumula has expanded completely into leaves, the coty- ledons may be removed without injuring the plant, and they very soon decay of themselves, it ap])ears, then, that this new otfice of the cotyledons is afterwards performed by that part of the plant which is above g- ...id. Thus we have traced the phenomena of germination as far as they have been detected. The facts are obvious ; but the manner in which they are produced is a profound secret. We can neither explain how the food enters into the vessels, how it is conveyed to the different parts of the plant, how it is deposited in every organ, uor how it is employed to increase the size of the old parts, or to form new parts. These phenomena are analogous to nothing in mechanics or chemistry, but resemble exactly the organization and nourishment of animals. They belong therefore to that difficult branch of science known by the name of Physiology. M. Vogel of Munich has made some experiments on the germi- na'Jon of seeds which deserve to be mentioned. He found, 1 . That seeds will not germinate in carbonate of barytes, hydrate of barytes, iodine bruised and moistened, kermes mineral, golden sulphur of anti- mony, oxide of bismuth, arseniate of lead, green oxide of chromium. 2. That they germinate, though very feebly, in carbonate of mag- nesia, copper tilings, sulphuret of antimony, red oxide of mercury, aqueous solution of iodine. 3. That hey germinate perfectly well in carbonate of lime, carbonate of strontian, litharge, red oxide of lead, phosphate of lead, black oxide of manganese, calomel, cinnabar.f CHAPTER IV. OF THE FOOD OF PLANTS. Plants, after they have germinated, do not remain stationary, but are continually increasing in slzcc A tree, for instance, every sea- son adds considerably to its former bulk. The root sends forth ne\N shoots, and the old ones become larger and thicker. The same increment takes place in the branches and the trunk. When we examine this increase more minutely, we find that a new layer of wood, or rather of alburnum,^ has been added to the tree in every * Encyc. Method. Physiol. Veg.?t. 42. t ^oMr. de Pharmacie, xvi. 406. X The wood, when v,e inspect it \n\\\ attention, is not, through its whole extent, the same ; the part of it next the barii is much softer and whiter, and more juicy than the rest, and has for that reason obtained a particular name ; it has been called the alburnum or aubier. The perfect wood is browner, and harder, and denser tliaii the alburnum, and the layers increase in density the nearer they are to the centre. y 1:' ^•l m!1 • . Ill r I'' .'Mill 968 FOOD OF PLANTS. i 'I part, nnd thid aiUlition has been mndo just under the bark. We iiud, tuo, that a layer of alburnum has assumed the appearance of perfect wood. Duhamel has shown also that a new layer of liber next to the alburnum, is formed every year. Uesidos this addition of vegetable (Ibre, a great number of leaves have been produced, and the tree puts forth flowers, and forms seeds. It is evident from all this, that a great deal of new matter is con- tinually making its appearance in plants. Hence, since it would be absurd to suppose that they create new matter, it must follow that they receive it by some channel or other. Plants, then, retpiirefo'nl as well as animals. Now, what is this food, and whence do they d> rive it ? These questions can only be answered by an attentive survey of the substances which are cortained in vegetables, and an examina- tion of those substances which are necessary for their vegetation. If we could succeed completely, it would throw a great deal of light upon the nature of soils and of manures, and on some of the most important questions in agriculture. IJut we are far indeed at pre- sent from being able to examine the subject to the bottom. 1. In the lirst place, it is certain that plants will not vegetate without water ; for whenever they are deprived of it thoy wither and die. Hence the well-known use of rains and dews, and the artificial watering of ground. Water, then, is at least an essential part of the food of plants. But many plants grow in pure water ; and therefore it may be questioned whether water is not the only food of plants. This opinion was adopted very long ago, and numerous experiments have been made in order to demonstrate it. Indeed it was the general belief of the 17th century; and some of the most successful improvers of the physiology of plants, in the 18th century, have embraced it. The most zealous advocates for it were, Van Helmont, Koyle, Bonnet, Duhamel, and Tillet. Van Helmont planted a willow which weighed 5 pounds, in an earthen vessel filled with 200 lbs. of soil previously dried in an oven, and then moistened with rain water. This vessel he sank into the earth, and he watered his willow, sometimes with rain, and some- times with distilled water. After five years it weighed 109;^ lbs., and the earth in which it was planted, when again dried, was found to have lost only 2 ounces of its original weight.* Here, it has been said, was an increase of 164 lbs., and yet the only food of the willow was pure water ; therefore it follows that pure water is sufficient to afford nourishment to plants. The insufficiency of this experi- ment to decide the question was first pointed out by Bergniann in 1773.t He showed, from the experiments of Margraff, that the rain water employed by Van Helmont contained in it as much cartli as could exist in the willow at the end of five years. For, accord- ing to the exj)eriments of Margraff, 1 pound of rain water contains I grain of earth.| The growth of the willow, therefore, by no means * Opera Van Helmont, p. 105. Figmentum, Sect. 30. t Opusc. V. 92. Coniplexionutn atque Mistionum Elementalium t Ibid. ii. 15 and 19. FOOD OF PLANTS. 069 ho bark. Wo appearance of layer of liber 3 this aclilition leen produced, matter is con- iice it would bo lust follow that , require fo'ul as c do they d' I'ive iittcntivc survey and an exaniina- beir vegetation, eat deal of ligbt ,me of the most T indeed at prc- bottom. vill not vegetate tthoy wither and and the artificial essential part of pure water; and not the only food TO, and numerous ite it. Indeed it iome of the most the 18th century, for it were, Van 15 and 19. proves that the earth which plants contain has been formed out of water. Besides, as Mr Kirwan has remarked,* the earthen vessel must have often absorbed nioisture from the surrounding earth, im- pregnated with whatever substance tho cartli contained ; for unglazed earthen vessels, as llalest and Tillett have shown, readily transmit moisture. Hence it is evident that no conclusion whatever can bo drawn from this experiment ; for all the substances which the willow contained, except water, may have been derived from the rain water, tho earth in the pot, and tiie moisture imbibed from the surrounding soil. The experiments of Duhamel and Tillet are equally inconclusive ; so that it is impossible from them to decide the question, whether water be the sole nourishment of plants or not ? Hut all the attempts hitherto made to raise plants from pure water have failed ; the plants vegetating only for a certain time, and never perfecting their seeds. These experiments were made by Ilassenfratz, Saussure, and others, with the same unfavourable rc3idt. Duhamel found, that an oak, which he had raised by water from an acorn, nmde less and less progress every year. We see, too, that those bulbous roots, such as hyacinths, tulips, &c., which are made to grow in water, unless tliey be planted in the earth every other year, refuse at last to flower, and even to vegetate ; especially if they produce new bulbous roots annually, and the old ones decay. From all these fiicts and experi- ments, it is reasonable to conclude that water ii not the sole food of plants. § So far, indeed, is water from being the sole food of plants, that in general only a certain proportion of it is serviceable, too much being jqually prejudicial to them as too little. Some plants, it is true, grow constantly in water, and will not vegetate in any other situa- tion ; but the rest are entirely destroyed when kept immersed in that fluid beyond a certain time. Most plants require a certain degree of moisture in order to vegetate well. This is one reason why different soiN are required for different plants. Rice, for instance, requires a very wet soil : were we to sow it in the ground on which wheat grows luxuriously, it would not succeed : and wheat, on the contrary, would rot in the rice ground. We should, therefore, in choosing a soil proper for the plants which we mean to raise, consider the quantity of moisture which is best adapted for them, and choose our soil accordingly. Now the u:yne3s or moisture of a soil depends upon two things ; the nature and proportions of the earths which compose it, and the quantity of rain which liills upon it. Every soil contains at least three earths, silica, lime, and alumina, and sometimes also magnesia. The silica is always in a state of sand. Now soils retain moisture longer or * Irish Trans, v. iCO. f Vcjet. Stat. i. t Mem. Par. 1772, 29. § The experiments of Braconnot, wiio lias endeavoured to prove tiiat water is tlie sole food of plants, are by no means decisive. See Ann. de Chim. Ixi. 187. He raised plants on sand and metallic oxiJes i)y means of water, and found that the plants had all the usual vegetabh', earthy, and alkaline constituents. But in ex- periments of that nature it is impossible to guard against every channel, by means of which these substances may have access to plants. I ' - ''I A Mi ■• 1 1 M I 1 1 li i|B|i i. I^IB i 970 FOOD OF I'LANTS. shorter according to tho proportions of tlioso eartlia. Those which contain the greatest s siir la Vegetation, ]). 281. f Tin e soils were composed of tiie t'oUowiiig ingredients : — (irauitic. ralcarcmis. Silica 7J'25 Carbonate of lime 98-000 Alumina 13-25 Alumina . 0-G-2J Lime 1-74 Oxide of iron 0-C'2a Iron and manganese !)-00 I'etrolenm 0-0-25 I ■ . '!« (^ 11 99-24 99-27.5 972 FOOD OF PLANTS. lii'l l|| ; Potash ..... Alkaline sulphates and muriates Carbonate of lime . Carbonate of magnesia Silica . . . . . Alumina . . . . Metallic oxides Calear. 15 63 10 99-81 94* Thus it cannot be doubted, that the proportion of earthy matter contained in plants is considerably influenced by the nature of the soil on which they grow ; but whether plants derive the whole of these fixed principles from the soil, or whether they are capable of forming them to a certain extent by the unknown powers of vegeta- tion, are questions not yet finally decided. The experiments of Saussure would lead us to believe, that all the earths found in plants are absorbed from the soil ; while those of Schrader seem to prove, that a portion of them is formed by vegetation, even when plants are so situated that they can derive no fixed principle from the soil on which they grow. The Berlin Academy proposed as a prize question. To determine the earthy constituents of the different hinds of corn, and to ascertain whether these earthy parts are formed by the process of vegetation. The prize was gained by Schrader, an apothecary in Berlin, and the result of his experiments was published by the Academy in 1800. He analyzed the seeds of wheat, rye, barley, and oats, and ascer- tained the portion of earth which each contains. He analyzed in the same manner rye-straw. After having in this manner determined the proportion of earth which these seeds contained, he endeavoured to make them grow in some medium which could not furnish any earthy ingredient whatever. For a long time his attempts were baffled, every substance tried containing less or more of earth, and being therefore improper. At last he found that sulphur, in tlie state of flowers, might be used with si^ccess, as it contained no earthy matter whatever, and as the seeds grew in it, and sent out their roots perfectly well, when it was properly moistened with water. Theoxides of antimony and zinc were the substances which answered best after sulphur. The seeds, then, were planted in sulphur, placed in a garden at a distance from all dust, put into a box to which the light and the air had free access, but from which all dust and rain were carefully excluded, and they were watered with distilled water. The corn raised in this manner vvas found by Schrader to contain more earthy matter than had existed in the seeds from which it had grown.t Here, then, it would appear was the formation of earthy matter, unless we conceive that the air might have contained • Pliil. Mag. viii. 185. Jour, dc Phys. lii. 27. f Braconnot's experiments agree with tliose of Schrader, but they were not made with the same precautions. See Ann. de Chim. Ixi. 187. ic. n Calear. 15 63 l(j 94* of earthy nicatter the nature of the ■ive the whole of ey are capable of powers of vegeta- e experiments of IS found in plants er seem to prove, sven when plants iple from the soil ion, To determine and to ascertain ■ess of vegetation. J in Berlin, and Academy in 1800. oats, and asccr- Ile analyzed in inner determined 1, he endeavoured not furnish any s attempts were •re of earth, and t sulphur, in the itained no earthy d sent out their ned with water. '< which answered 1 sulphur, placed a box to which ch all dust and 3d with distilled by Schrader to eeds from which ;he formation of ; have contained 7. but they were not im FOOD OF PLANTS. S^ussur^S nl^ "1"'"^'"" of chemists to ti.e f ' . '"'''' ^"^ P^'"" Uieans sufficient till -. ^''^ ^^^ts above statp^l t T- ,'^^^' A Ti • 1 "^ Processes nf usually preJtVT"" P-feat. °' {Cl^ rV"°™™ dower &r?. '""■'^■^' "'"-ate of potash ;;„..,'""" "^ «"'ia is Gehlen's Jnnr ;;: ^o„ . _ j ua to ' Gehlen's Jour. iii. 539. t Ibid. 563. t Saussure, Recherches, p. 264. 1+ 1 ■* < mm i?;'i' jf 'ivj r t I .f » ! ii 'If 1 1 4 ?' r '■ i f i ,y| 'I 974 FOOD OF PLANTS. vegetation. He dissolved the following substances in water, in such proportions, that each solution contained t^o^^J P^"'*' "^. ^*^ weight of the substance dissolved, except the last, which contained j'yth part : — 1 Muriate of potash 2 Muriate of socja 3 Nitrate of lime 4 Sulphate of soda effloresced 6 Muriate of ammonia 6 Acetate of lime 7 Sulphate of copper 8 Crystals of sugar 9 Gum arable 1 Extract of soil. Into each of these solutions he put plants of polygonum persicaric, or of bideiis cannabina, furnished with their roots. The polygonum grew for live weeks in the solutions of muriate of potash, nitrate of lime, muriate of soda, sulphate of soda, and extract of soil ; and the roots increased in them as usual. It lan- guished in the solution of sal ammoniac, and the roots made no progress. It died in eight or ten days in the solutions of gum and acetate of lime, and in less than three days in the solution of sul- phate of copper. When such a number of plants of polygonum were put into the solutions as to absorb one half of each in two days, the remaining half was found to have lost very ditferent proportions of the salt which it had originally contained. Suppose the portion of salt originally in solution to be 100, the following table exhibits t!je quantity of each which had disappeared when one half of the liquid was absorbed : — Muriate of potash . . . 14*7 Muriate of soda . . . 13*0 Nitrate of lime . . . 4*0 Sulphate of soda . . . 14'4 Muriate of ammonia . . . 12*0 Acetate of lime . . . 8*0 Sulphate of copper . . . 47'0 Sugar ..... 29"0 Gum ..... 9*0 Extract of soil .... 5*0 The bidens absorbed pretty much the same proportions, but in general did not vegetate so long as the polygonum. In these trials, it was the sulphate of copper and the sugar that were absorbed in greatest abundance, and these were the substances which proved most injurious to the plant. Saussure explains this apparent anomaly by supposing that a portion of the roots were soon destroyed in these liquids, and that then they absorbed the solution iiuli?- criminately.* * S;iu=! .inately. Saussure supposes that the difference depends rather upon the degree of liquidity which the solution possesses, than upon any discriminating power in the root. But if this were the case, it would be difficult to explain how so much greater a proportion of v/ater should be absorbed than of the salt which it holds in solution. 5. Water, then, carbonic acid, and oxygen, and perhaps also earths and salts, constitute a part of the food of plants ; but it is very clear that the whole food is not furnished by these substances. It is well known, that if vegetables be successively raised on the same ground, they at last exhaust it, or render it sterile ; and to prevent this, fanners are obliged to supply their grounds annually with a quantity of manure. Without this manure, or some equiva- lent, plants cannot be made to thrive, or to perfect their seeds. Neither watjr, air, nor earths, nor salts, will prevent them from perishing. Giobert mixed together the four earths, silica, alumina, lime, and magnesia, in the proper proportions to constitute a fertile soil; an J after moistening them with water, planted several vegetables h'k... ill > ■';. ■i 1 976 FOOD or PLANTS. I Iji' li :j. in them : but none of them grew well till he moistened his soil with water from a dunghill. Lanipadiua planted different vegetables in compartments of his garden, filled each with one of the pure earths, and watered them with the liquor which exuded from a dunghill. They all grew, notwithstanding the diversity of the soil ; and each contained the usual earthy constituents of plants, notwithstanding the absence of these constituents from the soil. It is not the earths which constitute a fertile soil, but the remains of animal and vegetable substances, and the proportion of these capable of being held in solution by water. It appears from the experiments of Mr Hassenfratz, that subiitances employed as manures produce effects in times proportioned to their degree of putrefac- tion ; those substances which are most putrid producing the most speedy effects, and of course soonest losing their efficacy. Having manured two pieces of the same kind of soil, the one with a mixture of dung and straw highly putrefied, the other with the same mixture newly made, and the straw almost fresh, he observed, that during the first year, the plants .hich grew on the land manured with the putrefied dung produced a much better crop than the other ■; but the second year (no new dung being added), tho ground whicli had been manured with the unputrefied dung produced the best crop; the same thing took place the third year, after which, both , itemed to be equally exhausted.* Here it is evident that the put. efied dung acted suonest. and was soonest exhausted. It follows it im this, that carbon only acts as a manure when in a particular state of combination ; and this state, whatever it may be, is evidently produced by ])utrefaction. Another experiment of the same chemist renders this truth still more evident. lie allowed shavings of wood to remain for about ten months in a moist place till they began to putrefy, and then spread them over a piece of ground by way of manure. The first two years this piece of ground produced nothing more than others which had \iot been manured at all ; the third year it was better, the fourth year it was still better, the fifth year it reached its maximum of fertility ; after which it declined con- stantly till the ninth, when it was quite exhausted.f Here the effect of the manure evidently depended upon its progress in putrefaction. When vegetables are allowed to putrefy in the open air, they are converted in a loose black substance, well known under the name vegetable mould. On this mould plants grow with great vigour. It is the --ubstance which renders newly cultivated lands in America, &c., so fertile. When exposed to the air, in the course of cultiva- tion, it is gradually wasted and destroyed, and the lands are thus imp;?verished. This vegetable mould, therefore, is obviously one of the grand s(,urces of the food of plants. It deserves, therefore, an accurate examination. To Saussure and Einhof wc are indebted for a chemical examina- tion of its properties and constituents. Saussure employed in bis ♦ Ann. de Chim. xiv. 57. f Ibid. xiv. 58. istened his soil with fFerent vegetables in i of the pure earths, ed from a dunghill. ' the soil ; and each its, notwithstanding oil, but the remains proportion of these t appears from the inployed as manures degree of putrefac- troducing the most r efficac}'. Having one with a mixture ;h the same mixture served, that during 1 manured with the lian the other •; but I ground whicli had :ed the best crop; vhich, both itemed that the put.efied It follows fntn 1 a particular state ly be, is evidently )f the same chemist -I shavings of wood till they began to ground by way of 1 produced nothing [ at all ; the third tter, the fifth year li it declined con- •t Here the eflect !ss in putrefaction, open air, they are n under the name vith great vigour. lands in America, course of cultiva- the lands are thus is obviously one of rves, therefore, an roOJ) OF I'LANTS. iiii Carburetted hydrogen gas Carbonic acid ^ Water containin-ZpyrolV^ nate of ammonia ° { ^["pyreur:atic oil ^ ^iiarcoal Ashes ' ' * • 80 13 411 oxperimonts pure veo,.h.j i -. ^^^ trunks of trees or fS'"' '"''' ^^'""c'' ''e procur I «M . mixed.* W^a-Vu^ °* "ndccayed verrpf^M .'T^' '"-' ''""loved •■ndecayed oac vi?. 7'."" ^"•"'^"^^ts ; whirthr"^"^ ^''""^ '^''^^^> constituUr ^'^"^^^^ '-the *win.: ^o^Cs^ J^ ^J Muiiid. ^24 inches (French) n'fi • 29 53 grains (French) 10 . 51 . '•'•o'n the exporiruPnts of Finhnf -f ,., , , '^'"'"'' '^ '-W^-^ that the extract ob- fi'^eherches.sml.Voc cation,,,., GO +r,, , 1 i^' I ' 'I 'I t"' « W W 978 FOOD OF PLANTS. Jl t li! ttined from mould poss.C38C3 very nearly the properties of the ex- tractive principle. The mould which he employed in his experi- ments was from the soil of a wood, and had heen formed by the leaves of the trees and the putrefied herbs. It was black, firm, produced no change on vegetable blues, and contained no undecayed plants.* Water, in which this mould was boiled, was at first colour- less ; but by exposure to the air it acquired a brownish tint. The substance whicli is held in solution possessed exactly the characters of extractive. Experiments upon vegetable mould have been made also by Bra- connot. lie found no portion of it soluble in water. His other results resembled those of Saussure. When an alkaline ley was boiled with mould a portion was dissolved. The residue had tlio exact appearancj of pit coal.t Besides this fertile vegetable mould, Einhof has examined another of a difiercnt nature, to which he has given the name of acid verje- table mould. It occurs i*" low-lying meadows and marshes, and the plants which grow upon it in those situations are the different spe- cies of carex, j'uncus, and criophornm. It constitutes also the prin cipal part of the moidd in high-hing situations, and moors where the soil is covered with heath {erica vidporis.) This mould is dis- tinguished from the preceding by containing a notable portion of phosphoric and acetic acids, which give it the property of redden- ing vegetable blues. The extractive which it contains is chiefly in- soluble in water.t This sour vegetable mould bears a considerable resemblance to peat, into which indeed it probably passes. Like it, peat contains a portion of phosphoric acid, and probably also of acetic acid, and an extractive readily soluble in alkalies, though but sparingly in water. § Einhof has observed, that acid vegetable mould never occurs in those soils which abound in lime, and that it is counteracted and brought to the state of good mould by the action of lime and marl, It is clear that these manures will neutralize the acids, and thus enable the extractive, and other vegetable substances, to be acted upon by the atmosphere, to yield carbonic acid, and to assume thoic i states M'hich arc proper for the nourishment of vegetables. It is | probable that they act also directly upon the vegetable matter, ai occasion decompositions favourable for vegetation. Hence tl efficacy of lime when applied to peat moss, and to sour lands general. Upon the whole, then, it appears that plants are fed chiefly I)} I that })ortion of vegetable matter which becomes soluble in water, and assumes the properties of extractive ; that the quantity of it in soil must neither be too great nor too small; that the insoluble part I of vegetable mould gradually assumes this state, either by the aetioiij of the atmosphere, or of earths or salts ; that the presence of aiij * (ielilen's Jour. vi. 373. X Gehleii, vi. 379. f Anil, lie Cliim. Ixi. 191. § Kinliof, (iehlen's Jour. iii. 400. •roperties of the ex~ oyed in his experi- becn formed by the It was black, firm, tained no undccayed 1, was at first coioiu*- •rownish tint. The actly the cliaracters n made also by Bra- 1 water. His other an alkaline ley was L'lie residue had the IS examined another name of acid vege- id marshes, and the 'e the difterent spe- itutes also the prin :i, and moors where This mould is dis- a notable portion of iroperty of redden- :)ntains is chiefly in- )eurs a considerable )ly passes. Like it, id probably also of alkalies, though but uld never occurs in 3 counteracted and 1 of Tune and marl, he acids, and thus :ance3, to be acted i md to assume those ' vegetables. It is ^ctable matter, and ition. Hence tlie| id to sour lands tOOD OF PLANTS. «cid, by counteractino- H,i« i ^^^ Animal manure, nr„l i , ™S"(aWc J'nown; thou.tl, .-l- '-'' "" *''« growth nf° ''^^''^^ ^vhich - this si^S-hai^r^^sv -^ ^^:^^ZTJ^ -^y '^ '"'^"er.f Thl L,?"'""' "/'' ^« '^P»" tlfe '^'^^^^'^^^^'^^''ttle- ^'-ces, hut ::i:y^z:t:;^!n^ «- ^-wS.;:srf -- '"-'""res, it is unnecessnr! , ^'^''^ «" the use of fl.p "^''^ '"''" stKueuts of wliir , h f ^ *" ''^'^^ «^ detail in ll i '° ""''"^'-^ as ' '5aSJx;ri;^r« ^t;;n:s;3^etin, the ^.od -•austed is pred ''t, f, t^l'^'-t;?" of the o U^^ f?^ « -'^7; ^•!f-o.nities of roots iL + ' V' ^"/^'"^'I' the .n-eate..Vn'^''„ '"?."?«* exhausted is preci 1;! f ^ *''' l'^^-^' Of reuHties of" roots Li ^n' ^" ^^'"^•'' ^hei:;;;:?' !' «««"««* •■"•e enalded, in so " , ^ ^""-easino. !„ ,,„.^ ^/^ 1^^^'^ *^'« ''"ots h'bres which tf t^ ' ""'^^ ^ destroyed }t V^'-?^ ^« ^ ^oo '•« i^'- i>V>Il i. fonnf ,; ?' f "^"' «"« i« form S n ' t!^ f '""' J^ ^"* '^^^•0 extremities oTtl ZlT "■'^'' ^^'^' ^'^-^ " '^^«- This, !»'•"' tl./stat'e o u '^'' ''''' ^^'«o wi :;r fT "'* ^««s «olu- ^)' -"cans o carbo •' ' ^ /"^'^^esia and a n in fnl f''"* ^^' ^^« P"''^ f'^'ve shown t'nt " "m-^ ^'' ' «"'» ^^er ' ." "m^"^^ '^^ 'i^^dered so i': Gel.Ic's Jour. iii. 07^^ + *^7«"J"e cics Arbres, iii. o.39_ 1^,. i> ' *: tI()i'"=.'■ render the smi"! part of *„ f /' ^^ """'o means ir „m ., " "=™" Possi. several circumJ.^ ^ ^)' several nhv^inJ^ -T ^-^''^^^'entit nus. ■•'o-ain vecreE „7 " ",?* ^^'S^etato well iC ,, h' '* '^ "'^Jl known plants have been '" ^ "'"" «'''«" Planted .fi-f^'^' T? ^^'«t so.ne accountedir on or^"'"^- '^^^ese Jact' Z'£TV\''' ^"^^tain n>atter em tted bf Jh' ^''"'^'P^'^^- ^^ there be anv '"'^'' "'"^^ ^' ''^PPensin the S .' '°°*'' ^^ '« "^uch more 7n ?7f"^""^^*'«"« fo'Hl, after d eslion •''^' 'f ^'^ffetation; thTk f '^"^^''" ^^^^ this quires. Keisfr cl:-f "^^ '^^ ^« ^'^^ purpose uP t'^l ^^«» ^he "•e ffiven nm r ?''^'''*' ^''^ resinous Sf-, ^'''^' tiie root re- -tt?r"Tbe\^,;;b""<^«ntIy by ceTarpC: '«^^"""^J"'^^«that the cherry tree i-'"?.'""""^J ^y the nfne till ' "^"^^^'nentitious ^n tl.e same ;.aV t ? "' ^"' "P'"^^"' t^'e e^em^S? "J^^''^ ^"^" V tl'e elm are in^L '"^""^ ^^'^«" «ut by the Th "f 't^'' P'^^^^s. Mr Kni'ht toT" P^^^^^'-^^ent. ^ ''' "''^' ^"^ ^^e uhnin by J-S^^t»^^^ and different votf ",?''"' ""^^ ^«'^dy' prep^edl r'^^'-^ ^" *''« ^Ibu;. , '>ave a?taS S 7f "«'* AicordClo ?n,t' 'f""''^^^^ *° *!'« ' of summer t Z " ' S''^^'^'^' ^^^re employed T'-P^^".*'' ^^^«'' "^ey hi I '■n-?i^ til ;:'li^-i 989 MOTION OF THE SAP. \ f stances in a satisfactory manner that appeared formerly altogetlior Anomalous. Ho ascertained, by exjieriments, that the sap increases in density as it ascends towards the leaves. Sap extracted from the syca- more, close to the f,'round, was of the specific gravity of 1'004; while that which flowed out at the height of seven feet was 1"008, and at the height of twelve feet 1*0 12. The sap of tlie hirch was somewhat lighter, but its comparative increasic of density, according to its height, was the same. When extracted near the ground, the sap, both of the sycamore and birch, was nearly tasteless; but it became sensibly sweet at some height, and the sweetness increased with the distance from the ground. Thus it appears, that tlic quantity of vegetable matter in sap increases as it flows towards the leaves ; a direct proof that it imbibes and mixes with sometliiiii,' during its passage. That this matter was ludired in the alburmiin Mas rendered ])robable by comparing with each other the alburnum in winter and in summer. For, if nutriment be laid up in the alburnum in winter, and employed in summer for the purposes of vegetation, it is obvious that tlie alburnum during winter ought to be denser, and ought to yield more extract to water, than the same substance in summer : both of which Mr Knight found to bo tlio case. Oak ])()les, of the same age, and growing from the same stool, were felled, partly in Dc('(Mui)er and ])artly in May. Tliey were placeil in the same situation, and dried for seven weeks by a fire. The specific gravity of the winter felled wood was 0*079, of the summer 0"()09. When the alburnmn alone was weighed, the specific gravity of the winter felled was 0-583 ; of the sutnmcr foiled 0'533. One thousand grains of each being mixed with six ounees of boiling water, and left to macerate for 24 hours, the winter felled infusion was much deeper coloured than tiie other. Its specilic gravity was 1'002; while that of the summer i'ellod infusion was I'OOl. Tliis deposition of nutritious matter exjdains why tlie alburnntn of trees felled in winter is much more solid and valuaMo than the alburnum of trees felled in summer. The sap, as Dr Hales has shown us, ascends with a very consid- erable force. It issued during tlK^ bleeding season with such impe- tuosity from the cut end of a vine branch, that it supported a coliiimi of mercury 32^ inches high.* Now, what is the particular channel through which the sap ascends, and what is the cause of the force with mIucIi it moves? These are questions which have excited a great deal of the attoii- ti(m of those philosiiphers who have made the physiology of vegc- tablos their particular study ; but the examination of them is attended with so many diihcultics that they are very far from bein; decided. It is certain that tlie sap flows from the roots towards the summit I of the tree. For if in the bleeding season a number of openings bc| « Vf'tr. Slat. i. ]0:>. formerly nltogetlior MOTION OJ- THE y^,.^ til wliicli it move »>«Je in the tree tUn . i • ' Wa and Honnet nU.U , i : ^"" "'ffljcst of nU • .... i ■ -^ ' " "■* '^st even w£' t ; d'',V" ""■• "•"'= f°' « n, rZ;'''" ""'"'> ""d ■i'l.cj;;,"';",' ?„^ 7,7 ' »" tl.o l«rk. ^'" ""'" " '™ "»'»«3 our plant , ill":"'" """ "■'"••™™r tl.. albu.™! " ? "l";' ''''™«'' "'= «U tl,r„u, , tl, If "W""™"™ tl, ore Now T,""'' " ""W t"i'e therefore of M^I ' i ''!' ''^"''"y u, su(:ces fd V^ ''' ?"^ I'o could f „d "^ "'7' ?^ the assistance ( f t'lu I ^^^'^'^^.^S'^"" into f ' ''^*'0"o (Ics Arbres, if- 7. + P''"- '''rans. J80I, p, .336. 'Ji - 1 ' 084 MOTION OF TilK SAP. Hut l)y what powers 1h the snp inadn to jisceml in these vcssoIn'.' niul not only to jiMcend, hut to move with very eoiisideriihh? foree; a force, as ilaleB huH sliowu, sutHoient to overeotiie the pressure ol' 43 feet perpendicuhir of water?* («rew aserihed this plienonienon to the levity of the sap; wiiich, aeoording to him, entered the phint in the state of a very li^flit vapour. Hut this opinion will not bear the sli^^litest examination. Malpi^rhi Huppotied that the sap was made to aseend hv the contrac- tion ami dilatation of the air contained in the air-vesstds. lint even were wo to grant that the trachejv are air vessels, the sap, accord- ing to this hypothesis, could only ascend when a change of tempera- ture takes place ; which is contrary to fact. And even if we wero to waive every objection of that kiml, the hypothesis would not ac- count for the circulation of the sap, unless the saj) vessels be pro- vided with valves. Now, the experiments of Hales anil Duiiaiiu'i show that no valves can ])ossibly exist in them : for branches ind)ib(' moisture nearly equally by either cud; and consequently the sap njoves with equal facility both upwards and downwards, which it could not do were there valves in the vessels. Hcsides, it is known, from many ex])criment9, that we may convert the roots of a tree into the branches, and the branches into the roots, by covering tlic branches with earth, and exposing the roots to the air. t Now, this would be impossible if the sap vessels were provided with valves. The same remarks overturn the hyijothesis of M. do la Hire, which is merely that of Malpighi, exjiressed with greater j)rccision, and with a greater paradi^ of mechanical knowledge. Like Horelli, he placed the ascending power of the sap in the parenchyma. Ihit his very experiments, had he attended to tlicin with care, would have been sufficient to show the imperfection of his theory. The greater number of philosophers (for it is needless to men- tion those who, like Pcrrault, had recourse to fermentation, nor those who introduced the weight of the atmosphere) have ascribed the motion of the sap to capillary attraction. There exists an attraction between many solid bodies and liquids; in consequence of which, if these solid bodies be formed into small tubes, the liquid enters them, and rises in them to a certain hciglit. But this Is perceptible only when the diameter of the tube is very snudl. Hence the attraction has been denominated capillary. We know that there is such an attraction between vegetable fibres and watery liquids ; for such liquids will a.scend through dead vegetable matter. It is highly probable, therefore, that the food of jjiants enters the roots, in conseiiuence of the capillary attraction wliieli * Vc-nt. Stat. i. 107. •f- Mr Kni<^lit lias sliowii tliat the inverted shoots by no moans grow so well as when in their nainr;il position; and has even made it probatjio, that the vessels "I' the liurk are t'urnished with vaivc>!, or uiili sonietliinervaiion*' temiiera- d even if we wero josis wo\ihl not ac- sap vessels he \m)- ales ami Duhauu'l or hranches iinhilic nscquently the sap jwnwards, which it [csides, it is known, the roots of a tree )t9, hy covering the I) the' air. t Now, vere provided with othesis of M. th' la •essed with greater lianioal knowledge. of the yap in the P attended to them the imperfection of is needless to mcn- fcrmentation, nor jere) have ascribed I bodies and liqviiils; fornicd into small fo a certain height, k the tube is very [ted capillary. ^Ve l(>y the Scinic nuuiher nf liiuis : it is therefore precisely in the same sulr ii;; if ii \u'ic net >illracted at all. I f 'I .Mi ¥ I ^ ■'1^ .'I' 986 MOTION OF THE SAP. them a single foot by capillary attraction, and yet the sap rises in them to very great heights. If any person says that the sap vessels of plants gradually dimin- ish in diameter as they ascend ; and that, in consequence of this contrivance, they act precisely as an indefinite number of capillary tubes, one standmg upon another, the inferior serving as a reservoir for the superior — I answer, that the sap may ascend by that means to a considerable height : but certainly not in any greater quantity than if the whole sap vessel had been precisely of the bore of its upper extremity ; for the quantity of sap raised must depend upon the bore of the upper extremity, because it uuist all ])iiss through that extremity. l^jt farther, if the sap moved only in the vessels of plants by capillary attraction, it would be so far from flowing out at the ex- tremity of a branch, with a force sufficient to overcome the pressure of a column of water 43 feet high, that it could not flow out at all. It would be impossible in that case for any such thing as the bleed- ing of trees ever to happen. If we take a cnpillary tube, of such a bore that a liquid will rise in it six inches, and after the liquid has risen to its greatest height, break it short three inches from the bottom, none of the liquid in the under half flows over. The tube, thus shortened, continues indeed full, but not a single particle of liquid ever escapes from it. And how is it possible for it to escape ? The film, at the iipper extremity of the tubc; must certainly have as strong an attraction for the liquid as the film at the loiccr extremity. As part of the liquid is within its attracting distance, and as there is no part of the tube above to counterbalance this attraction, it must of necessity attract the liquid nearest it, and witli a force sufficient to counter- balance this attraction of the undermost film, how great soever we may suppose it. Of course no liquid can be forced up, and conse- quently none can flow out of the tube. Since, then, the sap Jloivs out at the upper extremity of the sap vessels of plants, we are abso- lutely certain that it does not ascend in them merely by its capillary attraction, but that there is some other cause. It is impossible, therefore, to account for the motion of the sa)) in plants by any mechanical or chemical principles whatever ; and he who ascribes it to these principles has not formed to himself any clear or accurate conception of the subject. We know indeed that heat is an agent ; for Dr Walker found that the ascent of the sap is much promoted by heat, and that after it had begun to flow from several incisions, cold made it give over flowing from the higher orifices while it continued to flow at the lower.* But this cannot be owing to the dilating power of heat ; for unless the sap vessels of plants were furnished with valves, dilatation would rather retard than promote the ascent of the sap. Wo must, therefore, ascribe it to some other cause : the vessels ♦ FiJin, Tratif. i. MOTION OF THE SAP. 987 e sap rises m idually dimin- uence of tliis ^r of capillary as a reservoir by that means •eater quantity the bore of its t depend upon I pass through Is of plants by out at the cx- me the pressure How out at all. ng as the bleed- L liquitl will rise greatest height, of the liquid in tened, continues escapes from it. Im, at the Wlf'' )ii \y. I. ^'^■l 988 FUNCTIONS Ol' THE LKAVES. milky juice of that i)limt flows out at both ends so completely, that if afterwards we cut the portion of the stem in the middle no juice whatever appears. Now it is impossible that these phenomena could take place without a contraction of the vessels ; for the vessels in that part of the stem which has been detached cannot have been more than full ; and their diameter is so small, that if it were to continue unaltered, the capillary attraction would be more than sufficient to retain their contents, and consequently not a drop flow out. Since, therefore, the whole liquid escapes, it must be driven out forcibly, and consequently the vessels must contract. It seems pretty plain, too, that the vessels are excited to contract by various stimuli ; the experiments of Coulomb and Saussure render this jjrobable, and an observation of Dr Smith Barton makes it next to certain. He found that plants growinfj in water vege- tated with much greater vigour, provided a little camphor was thrown into the water.* CHAPTER VI. O F T HE FUNCTIONS O F T H E LEAVE S. It has been ascertained that the sap ascends to the leaves, that it there undergoes certain alterations, and is converted into anotlier fluid called the sitcais proprius, peculiar juice, or true sap ; which, like the blood in animals, is afterwards employed in forming the various substances found in plants. Now, the changes which the sap undergoes in the leaves, provided we can trace them, must throw a great deal of light upon the nature of vegetation. These changes are produced in part during the day, in part during the night. Now, as the functions of the leaves during the day are very difi'er- ent from what they are during the night, it will be proper to con- sider them separately. I. No sooner has the sap arrived at the leaves, than a great part of it is thrown off by evaporation. 1. The quantity thus perspired bears a very great proportion to the moisture imbibed. Dr Woodward found that a sprig of mint, weighing 27 grains, in 77 days imbibed 2558 grains of water, and yet its weight was only increased 15 grains; therefore it must have given out 2543 grains. The same experiment was repeated by tills philosopher on other plants ; the following table exhibits the result :f Aim. (Ic C'liini. xxiii. (3;). f Pi/il. TiMiis. l(;!if>, xxix. 193. FUNCTIONS OF THE LEAVES. 989 npletcly, that (Idle no juice e phenomena [or the vessels not have been ; if it were to be more than ot a drop flow nust be driven ■act. ited to contract and Saussure 1 I3arton makes in water vegc- 1 camphor was A V KS. le leaves, that it ted into another true sap ; which, in forming the anodes which the ihcm, must throw These changes iring the night. are very ditt'cf- p proper to cou- ihan a great part ;at proportion to ^ sprig of mint, fs of water, and lore it nmst have 1 repeated hy this lie exhibits the ;uilles, 1. Mem. The leaves of plants become gradually less and less fit for this transpiration ; for Sennebier found that when all other things are equal, the transpiration is much greater in May than in September.* Hence the reason that the leaves are renewed annually. Their organs become gradually unfit for performing their functions, and therefore it is necessary to renew them. Those trees which retain their leaves during the winter were found by Hales and succeeding physiologists to transpire less than others. It is now well known that these trees also renew their leaves. II. Leaves have also the property of absorbing carbonic acid gas from the atmosphere. 1. We are indebted for this very important discovery to the experiments of Dv Priestley. It had been long known that when a candle has been allowed to burn out in any quantity of air, no candle can afterwards be made to burn in it. In the year 1771, l)r Priestley made a sprig of mint vegetate for ten days in contact with a quantity of such air : after which he found that a candle would burn in it perfectly well.f This experiment he repeated frequently, and found that it was always attended with the same result. According to the opinion at that time universally received, that the burning of candles rendered air impure by communicating phlogiston to it, he concluded from it, that plants, while they vege- tate, absorb phlogiston. Carbonic acid gas was at that time supposed to contain phlogis- ton. It was natural, therefore, to suppose that it would afibrd nourishment to plants, since they had tlie property of absorbing phlogiston from the atmosphere. I)r Percival had published a set of experiments, by which he endeavoured to show that this was actually the case. These experiments induced Dr Priestley, in 1776, to consider the subject with more attention. But as, in all the experiments which he made, the jjlants confined in carbonic acid gas very soon died, he concluded that carbonic acid gas was not a food, but a poison to plants. $ Mr Henry of Manchester was led, in 1784, probably by the contrariety of these results, to examine the subject. His experiments, which were ])ublished in the Manchester Trans- actions,^ perfectly coincided with those of l)r Percival. For he found that carbonic acid gas, so far from killing plants, constantly promoted their g^'owth and vigour. Meanwhile Mr Sennebier was occupied at Geneva Avith the same subject ; and he published the result of his researches in his Memoircs Physico-Chijmiques about the year 1780. His experiments showed, in the clearest manner, that carbonic acid gas is used by plants as food. The same thing was supported by Ingenhousz in his second volume. The experi- ments of Saussurc junior, published in 1797, have at last put the subject beyond the reach of dispute. From a careful comparison of the experiments of these philosophers, it will not be difficult for 28j. * Encyc. Meth. Vp51. § Vol. ii. ,'UI. Ill ,,i:;?i 992 FUNCTIONS OF THE I,EAVKS. I I 1!!! lis to discover the various plienonicna, and to reconcile all the seeming contradictions which occur in them. The facts are as follows : — 2. Plants will not vegetate in an atmos|)licre of pure carbonic acid, nor 'f their atmosphere contains ^ths of its bulk of that gas. They veg.rate in the sun when ccmfined in {itmosphercs containing ji, jth, or ^th, of that gas, and the vegetation improves as tlio quantity of gas diminishes. When the atmosphere contains only , '^. tli of carbonic acid gas, plants grow in it considerably better in the sun, than when placed in an atmosphere of common air ; but wIkih plants are placed in the shade, the prest^uce oi call )v)nic acid always injures thi'li vegetation instead of proniotioif it." 3. Mr Saussure has shown, that plants vii' not v^eger.U'' in the sun when Totally deprived of carbonic uciu gas. Th', y '^iTetato indci'-d well enough in aW whi'ii has iieen j)i .viovj-ly doprived of carbonic acid gas; b ;t when a ipiantiiy of lime was jiut l.ito the glass vessel which contained then, the' no longer continued to grow, and tiie leaves in a fiew diivs fell ofF.t Tiie air, wlu;ii examined, wnrs fiund to c(>)itain no carbonic acid gas. Thf reason of this phenomenon is, that plant?^ (as " o shall se( cd't«i .vard:,) luive the power of form'ag and j^^i^inj.; out carbonic acid ; i certain cir- cumstances ; and this quantity h srific'ent to ccv*;nue tlieir vege- tation lor a ceitain time. But it thi* new Ibi^meu ,.as be also with- ilrawn, by qnickHuiie for instance, whicli abhorbs it the instant it ap'j)'Mrs, the leaves droop, and refuse to perform their functions. | Carbonic acid gas, then, applied to tiie leaves of plants, is essential tc vegetation. 4. TIk^ direct contrary takes place in the shade. Plants not only contiinie to vegetate when dcjuived of all carbonic acid by means of lime ; but they flourish nui.a than if it were allowed to remain. § 5. Dr Priestley, to whom we are indebted for many of the most inqiortant facts relative to vegetation, observed, in the year 1778, that plants, in certain circumstances, emitted oxygen gas ; || and Ingenhousz very soon after discovered that this gas is emitted by the leaves of plants, and only when they are exposed to the bright light of day. His method was to plunge the leaves of different plants into vessels full of water, and then expose them to the sun, as Honnet, who had observed the same phenomenon, though he had given a wrong explanation of it, had done before him. Bubbles of oxygen gas very soon detached themselves from the leaves, and * Suussure, Reclierolios Cliirniquos snr la Vegetation, p. .30. f Ann. (ie Cliiin. xxiv. 145, 148. X Bracomiot lias rendered it probaMo, tiiat in this experiment it was not tlie absoriee of carbonic acid, but the deleterious etlecls of the lime that killed tlie plants in Saiissnro's experiments. Ann. de Cliiin. Ixi. 187. § Sanssnre, Keeherches, p. ,16. M. Maeuire li;is fonnd that chlorine, nitric acid, nitrous gas, s-nlphnretted hydrogen, and ninriatic acid do not injure |)laiits during the day; but drstrov thorn during tlie niu'ht. Mem. Hipt. Nat. of Geneva, V. 283. II On Air, iii. '284. lirt. Nat. ol' Geneva, wore collected in nn ' Sennebier proved, that if H ^ P'*«ductive of all.t "^"^ That the dePoL •.• ^».''" ^' before.f ^^ °* '^' "«'"^es, .*I'>ge„houszo„ Ve^et i l. « raw silk, ? see Nicliolson's Jour, ii I'sa > .'• Ann. cJe Chim. et .lo P i, ;i "",' i ""• *'" f^^'"'"- xliii. 200. ^tncve. Method. Pl.v.Ji'^^.^^-'-g; 225. ; 3« fi ' :n li i ■1 ■> I 994 FUNCTIONS OF THE LEAVES. and even glass, when plunged into water, <^ave out oxygen gas l)y tlie light of the sun ; but when Sennebier repeated these experi- ments, they did not succeed.* It was probably the air contained in the water which separated in the Count's expcriments.f 7. From tiie experiments of Saussure, we learn that the quantity of carbonic acid thus absorbed and decomposed varies greatly in different plants, even when placed in the same circumstances. The lythrum salicaria was found to absorb 7 or 8 times its bulk ol' this gas in a day ; while the cactus opuntia, and other fleshy-leaved plants, did not absorb above a fifth of that quantity. The portion absorbed, according to Saussure, depends upon the surface of the plant ; and therefore thin-leaved plants must absorb more than those that have fleshy leaves.^ 8. It does not appear that the whole of the oxygen contained in the carbonic acid absorbed is emitted again by the plant. A con- siderable portion of it seems to be retained. This, at least, is the result which follows from a set of experiments made by Saussure on purpose to ascertain the point. He mixed carbonic acid with com- mon air, in such a proportion that it occupied 7^ hundredths of the mass. Jars, standing over mercury (covered with a thin lihn of water), were filled with this mixture ; and plants of vinca minor, growing in a small vessel filled with water, were introduced into tiie jar. These plants, thus placed, were exposed for six successive days to the sun, from five in the morning to eleven, while the tem- perature of the air was 70°; during all which time they vegetated with great vigour. The bulk of the air in the jar was not sensibly altered. No carbonic acid could be detected in it. The propor- tion of oxygen was 24^ per cent. The following table exhibits tlie proportion of the constituents of this air, in French cubic inches, when put into the jar, and after the plants had vegetated in it six days.§ Wlion put in. Wlici< taken out. Azote .... 211-92 218-95 Oxygen . . . 5(5-33 71-05 Carbonic acid . . 21-75 0-00 290-00 290-00 Thus the whole 21-75 inches of carbonic acid were absorbed ; bull the oxygen emitted was only 14-72 inches, whereas the whole oxyiiciil in the carbonic acid would have amounted to 21-75 inches. Tliel difference, amounting to about seven inches, was made up by al quantity of azote, which, had been given out by the plants along will the oxygen. The following table exhibits the result of similar ex-I * Ann. de Cliim. i. 1 15. \ Dr Woodliouse triod tlic cxporiineiils willi filaments of asbcstus, baked hor>e-| hair, cotton, pannicles of rhus cotinus, cotton of the asclepias syriaca, hairy |)1uimI of clematis crispa, spikes of panicum glaiicum, charcoal powder ; each of these, kl affirms, yielded in water a little oxygen ijas, but ':ss pure than the leaves of planlil Nicholson's Jour. ii. 138. + Rechcrches Chimiqiics, p. 56. § Ibiil. p. 10. )ut oxyfyen gas by ated these experi- the air contained sritnents.t 1 that the quantity I varies greatly in cinnstances. The times its bulk of other floshy-leaved ity. The portion the surface of the rb more than those cygen contained in he plant. A con- ns, at least, is the ide by Saussure on nic acid with com- hundredths of tlie nth a thin iilm uf its of vinca minor, introduced into tiio for six successive 'en, while the tein- irne they vegetated ir was not sensibly I it. The propor- T table exhibits the ench cubic inches, i^egetated in it six Wlici. taken out 218-95 71-05 0-00 290-00 vere absorbed ; bull is the whole oxygen I 1-75 inches. Tliel vas made up by a I le plants along wiilil isult of similar evf ' asbestus, baked hor* »s syriaca, hairy iiliiineil ider ; each of these, lei lan the leaves of planli.[ § Ibid. 1). to. n;NcTioNs o. nn: lr,ves. ponments, made hv fl.: i -i ""'"bera denote cubic i„;i.?'''^^"J''"'''' "" "M'^r pi, plants. 995 All the of the oxvo-en nf fi,: ' .' '^"'* *"''ovv out ao-iin H,,. ''"'^'^osorb ,, . ^'^j'e,en or tills fjas m yo>() extremely small that it catuu)t well be appreciated. III. The firecn colour of plants has been shown, by SennebiiT, to depend ui)on the absorj)tion of carbonic acid. It appears only when plants vejrctate in the light ; for whon they vejietate in tlic dark they are white; and when exposed to the light they acquire a green colour in a very short time, in whatsoever situation they aro placed, even thontsh plunged in water, provided always that oxygen be present ; for Mr (iongh has shown, that light without oxygen has not the power of ])roducing the green colour.* Sennebier has observed, that when plants are made to vegetate in the dark, their etiolation is nuich diminished by mixing a little hydrogen gas with the air that siuTounds them.t Ingenhousz had already remarked, that when a little hydrogen gas is added to the air in which plants vegetate, evon in the light, it renders their verdure deeper :J fnid he seems to think also, that he has proved by ex- periments, that plants absorb hydrogen gas in these circumstance:^.^ Mr Ilumbolt has observed that the poa annua and compn'ssa, phin- taffo lanccolata, trifolium arvcnsc, cliieranthus c/ieiri, fic/ttn verticil- fafus, and several other j)lants which grow in the galleries of mines, rerain their green colour even in the dark, and that in these cases the air around them contains a (luantlty of hydrogen gas. This philosopher concludes, from his observations, that the white colour of etiolated plants is occasioned by their letaining an unusual pro- portion of oxygen, and that this is prevented by surrounding them with hydrogen gas. This may perhaps be true in certain casoj); but the experiments of Mr Gough, mentioned above, are sufficient to prove that the retention of oxygen is not the ordy ditferenee be- tween green and etiolated plants. || The green colouring mjitter of plants has been shown by KoucIIl' to be of a resinous nature. From this, and from the circum- stance of its being formed only in the light, IkM'thollet has inferred that the leaves of plants have the property of decomposing water iu< well as carbonic acid when exposed to the light of the sun. Tlu' oxygen emitted, according to him, is derived partly from the decom- posed carbonic acid and ])artly from the water, while the carbon and hydrogen enter into the composition of the inflammable parts of tlie plant. This ingenious theory, though sufficiently ])robable, is not susceptible of direct proof. From the experiments of Saussure, we learn, that when plants are made to vegetate in ])ure water, in atmospheres destitute of carbonic acid gas, the quantity of tlieir fixed matter does not increase; but when their atmospheres contain * Man. Mem. iv. 501. t Encyc. Metli. Pliysiol. Vcget. 75. t Ann. (le Cliim. iii. 37- § Hjiil. (Jl. II Plants of a wliite colour, from vcj; itiiinp in tlie dark, am calleil etiolated, li'oi« j a Frcncli word wliicli si^jruifics a star, us if tlicy grew l)y star-h'jlit. ',"■;■"' "r. ti«" .1,, ,;^tMZ^ ".'■'■""«-■ tin., w.,'7'r t M' I". Munc. I,.,. ., •Itel»i-cl.c.s,|,.«i7 ^ - "''''™S 141 1,1 p ' n ^ijid. ji, |;»7. I ' li 9!)8 riiNcrioNS oi rill, i.u.wfcs. ■'r tlu'iii to II pnste for cxiunplf, all aliMorptio.' '.>f oxygon Is preventoil, tlioiigli u portion of it is ovon tluiii oonvcrttid into carbonic acid by tbo action (»f tbc^ curboniu'coiis matter ])rcscnt.* 4. Tin' oxygon tbiirt inspired by tbe leaves of plants, i» not sepa- rated from tliein again by putting tliein into tbo exliansted recoivor of tlu! uir-punip. Hy tbat means, indeed, tliey yielil a little air, but always niucb loss tlian tbo oxNgcn absorbed; and tbia air ia precisely of tbo same nature witb tbe atniosiibere in wbieli tbey wore confined. Neitlier is tbo oxygen extricated by exposing the leaves to tbo greatest beat wliicb tbey are caj)ablo of bearing with- out being destroyed.! 5. There id rousoii to believe that the oxygen gas thus absorbed by plants is oonvcrtoii into carbonic acid within the plant, and that it is only after the plant is saturated with this acid (if tbe expres- sion may be permitted), that tbo surrounding oxygen is partly con- verted into carbonic acid, by combining with the carbonaceous mut- ter of tbo plant. When tbo leaves are exi)osed to the light, this carbonic acid is decomposed, and a cpiantity of oxygen thrown out, usually greater than what was inspired. Hut tbe oxygon given out in the light (when plants grow in atmospheres destitute of carbonic acid) is always proportional to the oxygen inspired during tbe night; being always greatest when the plant has absorbed the greatest quantity of oxygen. 6. Plants (litfbr very much from each other in tbo quantity of oxygen which their leaves absorb during the night. Flosby-leavod plants absorb the least oxygen ; probably because tbey emit no car- bonic acid gas. Hence they can vegotate in high situations where tbe atmosphere is rarefied. Next in order come the evergreen trees, which though tbey absorb more oxygen than the flesh} -leaved plants, yet require much less than those trees which lose their loaves dur- ing winter. Those plants which flourish in marshy ground likewise absorb but little oxygen. Tbo following tables exhibit the result of Sanssure's experiments on this point. Tbe first column con- tains the names of tbe plants whoso leaves were e .iployed the second the month in which tbo experiments were m .do; ano the third the bulk of oxygen absorbed, supposing tbe bulk of tbe haves used in each experiment to bo always I'OO.j I. Leaves of Evergreen Trees. I.cavea of Ulex aquifolium . Buxus sempervirens Prunus laurocerasus Ditto Viburnum tinus . Hedora helix * Saiissiiie, Rcclir relies, p. 71. Time. Oxygen abanrbed. September 0'8G September l-4 2-23 1-00 X ll)i'>. 1>. 9!». I.carv> u( Vinea minor Ditto Piniis abicR Uupleuruuj fruticosu'ii Junipcrus sabina Juniperus communia II. Leaves of Trees which lose their Leaves in J^inler. O«y»on I'lrn*. nbtiiilH'O June 1-50 beptomlier . 0-93 September . 3'00 May 4-00 .lune 2'()0 Junu 2-40 I.oavci of Time. AbiorltftJ Fagua sylvatica . August 8-00 Carpinus betulus May .VOO Ditto Septeud)er . G-OO Qucrcus robur May 5'50 Ditto September . 5'50 ^sculus hippocastanun I September . 4-80 Populus alba May (>-20 Ditto September . 4-36 Prunus Armeniaea Sej)tember . 8-00 Amygdalus Persica June (>-60 Ditto September . 4-20 Juglana regia May G-(JO Ditto Septeuiber . 4-40 Platanns oecidentalis September . 3-00 Robinia pseudo-acacia May 5-00 Ditto September . 6-70 Syringa vulgaris May . 3-36 Ditto September . 2-20 Fraxinus excelsior May . 4-32 Ditto September . 3-71 Pyrus May . 5-20 Ditto September . 3-40 Rosa centifolia . June . 5-40 Fagus castanea . July . 5-60 III. Leaves of Herbaceous Plants, not Aquatic. LeavM of Time. Oxygen abtnrbed Solanum tuberosum September . 2-50 Brasica oleracea Ditto, young leaves 2*40 Ditto Sept., old leaves . 2-00 Urtica urens September . 2-00 Mercurialis annua . Sept., in flower 2-33 Daucus carota September, ditto 1-90 Vicia faba . Before flowering 3-70 Ditto In flower 2-00 Ditto After ditto . 1-60 J I;, :i! 'ill m 1000 FUNCTIONS OF THE LEAVES. OxyKsn Leaven of Time. absorbed. Lilium candidum May, in flower 0-66 Ditto Sept., after ditto . 0-50 TropaGolum raajus Sept., in flower 3-00 Digitalis ambigua July 2-00 Brassica rapa Sept., in flower 1-25 Avena sativa June, before ditto 2-70 Triticum ajstivum May, before ditto 5-00 Pisum sativum . May, in flower 3-72 Ruta graveolens August 2-00 IV. Leaves of Aquatic Plants. Leaves of Time. Oxycen absorbed. Alisma plantago August 0-70 Inula dysenterica September . 1-60 Epilobium moUc . Sept., in flower 1-90 Sisymbrium nasturtium September . 1-60 Polygonum Persicaria Sept., in flower 2-00 Veronica beccabunga September . 1-70 Ranunculus reptans September . 150 Ly thrum salicarla May, before flower 2-30 Caltha palustris . May 1-00 Carex acuta May . 2-25 V. Leaves of the Fleshy Plants. ■ Leaves of Time. "! O.KygPi) absorbed Cactus opuiitia . August 1-00 Agave Americana August 0-80 Sempervivum tectorum July 1-00 Sedum globosum September . 1-50 Saxifraga cotyledon September . O'UO Sedum reflexum Juno 1-70 Stapelia variegata July 0'63 Mesembryanthemum \ deltoides ' July . . 1-70 7. It is not improbable, that by tlic absorption of oxygen, and the formation of carbonic acid, a portion of heat may be evolved, as Saussure supposes ; though the quantity must be too small to be appreciated. It appears, that in certain cases a very considerable degree of heat is produced by vegetables ; though it has not yet been ascertained 'A'hether the appearance of it is connected with the absorption of oxygen. It has been shown in a preceding Chapter, that in certain cases a good deal of heat is evolved by plants, while the oxygen absorbed and converted into carbonic acid is proportionally great. It i.s not Oxygen absorbed r 0-66 tto 0-50 Br 3-00 2-00 jr . 1-25 itto 2-70 itto 5-00 3-72 2-00 onnected witli tlic rnNCTioNs or t„, ,,,,,^^ unreasonable to sunnn *i '^01 absorb oxygen ''",/^'^ experiments of >^.„« carbonic ^^i^TLned to tre,'" ^--^"dtrth:Vt' ^'^-^^^^^ J'kewise absorb it p?„^'^^ ^^V^^ to be decomposed ^tI"^^* ^^« , Thus it appea ; th!t 7''' ^" ""* ^^P^nd Sout >>. '"'""""^'^^ they form with if !* * • """- ^^^ night nlanT, .K f P^««<^nce. t"nes emitte to.; £"^Vr^^ ' ^'^^^ ^ Po S ^JT^ «Wn; that part is retained^ 5 , "''^'' ^ ^i^le azote h. f .i ' S^as is some- J^iants win iot ,; "^ decomposed by 'he'L,\"^ *\'^t the greatest supplied th Lih "^'^'^""^ ^'''« "ight V ii'nin .-^"''"^ *h« %. during the dnv? "' '^'''^' P'-ovided hp " ^"^'^r' ^^^n thou4 V Tl n , ^ ''^ constantly withdrawn . f.^^^"^" ^"^'"^^d by them air. Tn^ h!?? '^P'^'^*^ abso^^ water t '\'PP''^^^^ of II ;; e^: "^i7r°'^ ^ A: e'avt 3^^"^ .vegeta/e 'S toVr" t'- leaves be?o git^J^ f^ ?^^^^^^-n « ^ vh if b^ T'^'^ faces of leaves ""'""'"'' S'™g yet boon detecfcl M,: T''"I« "I™ by other, i ■ ■ i ,. ii ■II )' M. 1002 FUNCTIONS OF THE LEAVES. m ; ; i I I m 1 M has been converted by the operations performed during the day, nor the new substances formed by the operations of the night. We have reason, however, to conclude, tliat during the day the carbon of the sap is increased, and that during the night the hydrogen and oxygen are increased ; but the precise new substances formed are unknown to us. Nor let any one suppose that tlie increase of the hydrogen and of the oxygen of the sap is the same thing as the addition of a quantity of water. In v/ater, oxygen and hydrogen are already combined together in a certain proporiion ; and this combination must be broken before these elementary bodies can enter into those triple compounds with carbon, of which a great part of the vegetable products consist. We have not the smallest conception of the manner in which these triple combinations are formed, and as little of the manner in which the bodies which compose vegetable substfinces are combined together. Tlie combination may, for any thing we know to the contrary, be very complicated : though it consists wholly of three ingredients : and analogy leads us to suppose that it actually is very complicated : for in chemistry it may be considered as a truth, to which at present few or no excep- tions are known, that bodies are decomposed with a facility inversely as the simplicity of their composition ; that is to say, that those bodies which consist of the fewest ingredients arc most difficultly decomposed, and that those which are formed of many ingredients are decomposed with the greatest facility. Neither let any one suppose that the absorption of carbonic acid gas during the day is balanced by the quantity emitted during the night ; and that therefore there is no increase of carbon ; for Ingen- housz and Saussure have shown that the quantity of oxygen gas eniitted during the day is much greater than the carbonic acid gas emitted during the night ; and that in favourable circumstances, the quantity of oxygen gas in the air surrounding plants is increased jind the carbonic acid gas diminished; so much so, that both Dr Priestley and Dr Ingenhousz found, that air which had been spoiled by a lighted candle, or by animals, was -endered as good as ever by plants. Now we know that combustion and respiration diminish the oxygen gas, and add carbonic acid gas to air ; therefore vege- tation, which restores the purity of air altered by these processes, must increase the oxygen, and diminish the carbonic acid gas of that air ; consequently the quantity of carbonic acid gas absorbed by plants during the day is greater than the quantity emitted by them during the night ; and of course the carbon of the sap is in- creased in the leaves. It is true, that when plants are made to vegetate for a number of days in a, given quantity of air, its ingredients are not found to be altered. Thus Hassenfratz ascertained that the air, in which young chesnuts vegetate for a number of days together, was not altered in its properties, whether the chesnuts were vegetating in water or in earth ;• and Saussure, junior, proved that peas growing for ten ' Ann. (Ic Chim. xiii. 325. PKCULIAU JUICES OF I'LANTS. 1003 ng t\ie day, nor le night. We iay the carbon 3 hydrogen and ces ibrmed are increase of the le thing as the and hydrogen riion; and this tary bodies can f which a great not the smallest ombinations are 13 which compose •ombination may, plicated : though logy leads us to V In chemistry it few or no excep- , facility inversely ,0 say, that those •c most difficultly many ingredients n of carbonic acid Imitted during the arbon ; for Ingen- ;ty of oxygen gas carbonic acid gas ile circumstances, plants is increased so, that both Dr L had been spoiled IS good as ever by spiration diminish ; therefore vcge- these processes, ,onic acid gas of Lcid gas absorbed intity emitted by of the sap is i"" le for a number of \i not found to be [r, in which youiig las not altered ui lig in water or ui 1 growing fov ten days in water did not alter the surrounding air.* But this is pre- cisely what ought to be the case, and what must take place, provided the conclusions which I have drawn be just. For if plants only emit oxygen gas by absorbing and decomposing carbonic acid gas, it is evident, that unless carbonic acid gas be present, they can emit no oxygen gas ; and whenever they have decomposed all the car- bonic acid gas contained in a given quantity of air, we have no longer any reason to look for their emitting any more oxygen gas ; and if the quantity of carbonic acid gas emitted during the night be smaller than that absorbed during the day, it is evident that during the day the plant will constantly decompose all the acid which had been formed during the night. By these processes the mutual changes of day and night compensate each other ; and they are pre- vented from more than compensating each other by the forced state of the plant. It is probable, that when only part of a plant is made to vegetate in thi.^ forced state, some carhurelted sap (if I may be allowed the expression) is supplied by the rest of the plant ; and that therefore the quantity of carl)onic acid gas emitted during the night may bear a nearer proportion to that emitted in a state of nature than that of the absorption of fixed air can possibly do. And probably, even when the whole plant is thus conlined, the nightly process goes on for a certain time at the expense of the carbon already in the sap ; for Hasscnfratz found, that in these cases the quantity of carbon in the plant after it had vegetated for some time in the dark, was less than it had been when it began to vegetate.f This is the reason that plants growing in the dark, when confined, absorb all the oxygen gas, and emit carbonic acid gas : and whenever this has happened, they die ; because then neither the daily nor nightly processes can go on. CHAPTER VII. O 1" TH E r E C IJ L 1 A 11 JUICES O 1' PLAN T S. By these changes which go on in the leavos, the nature of the sap is altogether changed. It is now converted into v;hat is called the peculiar Juice, or true sap, and is fit for being assimilated to the dif- ferent parts of the plant, and for being eniplnved in the formation of those secretions which are necessary tor the purposes of the vegetable economy. The leaves, theref(. t Ibid. xiii. 188. 1004 PECULIAH JUICES OF PLANTS. lungs of animals. The leaves consequently are not mere ornaments ; they are the most important parts of tlie plant. Accordingly wo find, that whenever we strip a plant of its leaves, we strip it entirely of its vegetating powers till new leaves are formed. It is well known that when the leaves of plants are destroyed by insects tliey vefi^etate no longer, and that their fruit never makes any farther progress in ripening, but decays and dries up. Even in germina- tion no progress is made in the growth of the stem till the seed- leaves appear. As much food indeed is laid up in the cotyledons as advances the plant to a certain state : the root is prepared, and made ready to perform its functions ; but the sap which it iml)ibe.s must be tirst carried to the seed-leaves, and digested there, before it be proper for forming the plumula into a stem. Accordingly if the seed-leaves are cut oli', the ])lant refuses to vegetate. It will be very natural to ask, if this be true, how come the leaves themselves to be produced? I bad endeavoured to render it proba- ble, that food for the ])urpose of nourishing and developing them was laid up in the buds themselves ; but the experiments of Mr Knight, formerly detailed, have shown that the alburnum is the part of the tree in which this food is deposited. After the jdant has developed all tlu^ ])arts which are to appear during the summer, and after the buds are fabricated and rolled up, the leaves still con- tinue to nianufaclure new food, and to send it to the alburnum. Here it is deposited, and emj)loyed next sjjring in feeding and develo])ing those organs of jdants which are absolutely necessary for enabling them to perform the functions of vegetation. From this important fact, Mr Knight has drawn a number of curious conse(pienccs, of groat importance to the practical gardener ami fanner. This deposition of food for the future supply of the plant explains to us why the branch of a vine, if it be introduced into a hot-house during the winter, puts forth leaves and vegetates with vigour, while eveiy other part of the jjlant gives no signs of life. It explains to us also why the sap tlows out of trees very readily in spring before the leaves appear, i)ut after that the bleeding ceases altogether. It i nident that there can be scarcely any circulation of sap before the eaves appear ; for as there is no outlet, when the vessels are once full they can admit no more. It appears, however, from the bleeding, that the roots are ca])able of imbibing, and tlie vessels of circulating, the sap with vigour. Accordingly, whenever there is an outlet, they perform their functions as usual, and the tree bleeds ; that is, they send up a (luautiiy of sap to be digested as usual : but as there are no digesting organs, it Hows out, because the sap that tlows out would not have been imbibed at all, had it not been for the artificial opening. But when the digestive oruans appear, the tree will not bleed ; bccau^jc these organs require all the sap, and it is constantly tlowing to them. If a tree be de}>rived (»f its leaves, new leaves make their apjiear- ance, because they are already [)reparc(l for that piirno^e. Hut PECULIAR JUICES OF PLANTS. 1005 icvc ornaments ; Accorilingly we strip it entirely icd. It is well [ by insects tlicy .kcs any farther ven in germina- m till tlic seoil- tlie cotyledons as is prepared, and which it inibi\)es ted there, before , Accordingly if Tctatc. w come the leaves render it proba- developing them xpcriments of Mr i albnrnnm is the . After the plant uring the summer, he leaves still con- to the alburnum, no- in feeding and bsolutely necessary vegetation. From iivnnber of curious ical gardener and , the plant explains h\ into a hot-house Itates with vigour, signs of life- }* ics^^vorv readily in iic bleeding ceases [oly any circulation ^0 'outlet, when the appears, however, imbibing, and the M-dinglv, whenever as usual, and the sap to be digested , tlows out, because bed at all, had it [(^ digestive organs jro-ans rcfpnre au Inake their app^jav- lial pvirposo. but what would be the consequence if a tree were deprived of its leaves and of all its buds for five years back ? That plants do not vege- tate without leaves is evident from an experiment of Duhamel. He stripped the bark off a tree in ringlets, so as to leave five or six rings of it at some distance from each other, with no bark in the intervals. Some of these rings had buds and leaves ; these increased considerably in size ; but one ring which had none of these remained for years unaltered. Mr Knight found that a shoot of the vine, when deprived of its leaves died altogether.* The siiccus proprius, or peculiar Juice of plants, may be considered as analogous to the blood of animals. It is tlic food altered by digestion, and rendered fit for being assimilated and converted into ii ])art of the plant itself by the subsequent processes of vegetation. That it flc vvs from the leaves of the plant towards the roots appears from this circumstance, that when we make an Incision into the plant, into whatever position we put it, much more of the succus proprius flows from that side of the wound which is next the leaves and branches than from the other side : and this ha])pens even though the leaves and branches be lield undermost.t When a liga- tm-e is tied about a plant, a swelling appears above but not below the ligature. The vessels containing the peculiar juice have been traced by Mr Knight from the leaves into the cortical layers of the inner bark. I Hedwig, who has examined the vessels of plants with very great care, seems to consider them as of the same structure with the trachese ; but Mr Knight is of a different opinion. It appears evidently from the experiments of this last gentleman, that they communicate with no part of the plant which is situated at a greater distance from the root than the leaf from which they themselves originate. For when two circular incisions are made through the bark of a branch above and below a leaf, and at some distance from it, only that part of the portion confined between the two incisions which is situated below the leaf increases in size. From the expe- riments of Mr Knight, there is reason to believe that these vessels are much better calculated to carry the true sap from the leaves to- wards the roots, than in the contrary direction. By passing the slender shoots of a vine through the earth of a garden-pot, he made tliem send out roots. The shoots wore then cut off" from the parent tree, leaving an equal portion on each side of this new root. Each of these portions was turned up at a similar angle, and had a bud at a little distance from the cut-off' extremity. Here were two stems growing from one root. But the one was obviously inverted, while the other was in its natural position. In the first, the wood between the bud and the cut-off extremity increased in size; bui in the other it did not : indicating a disposition in the true sap to move in its original direction from the leaves to the root. In like manner, * I'liil. Trans. 1801, p. 338. f Rfli, Maucli. Mem, ii. i()± % I-hil. Tiaii'!. 1801, \). 337. ^1i : I i ;i :i fr ;h 1', i 1006 PECULIAR JUICES OF PLANTS, fe-i'lJ i M M when shoots of gooseberry and currant bushes were planted ui- verted, the upper part always decayed.* These experiments aro favourable to the opinion, that these vessels are furnished with valves. When all communication between the leaves and roots is cut off, by removing a portion of the bark all round the tree, it appears, from the experiments of Knight, that the alburnous vessels acquire the property of transmitting a portion of the true sap to the roots, so as to maintain the powers of vegetating ; but the quantity is greatly diminished. The surplus appears to be lodged in the albur- num, which thus becomes denser ; and if the plant be siUowed to vegetate, this food is expended next season upon the upper part of the plant. Thus the quantity of blossom on the branch of an apple tree is greatly increased, by removing a section of its bark the sea- son before the blossom is to appear.f The true sap is easily known by its colour and its consistence. In some plants it is green, in some red, in many milky. It cannot be doubted that its motion in the vessels is performed in the same way as that of the sap. If we had any metliod of obtaining this peculiar juice in a state of purity, the analysis of it would throw a great deal of light upon vegetation ; but this is scarcely p. Ksible, as we cannot extract it without dividing at the same time the vessels which contain the sap. In many cases, however, the peculiar juice may be known by its colour, and then its analysis may be ])erfoniicd with an approacli towards accuracy. The facts respecting its constituents, liitherto ascertained by chemists, have, as far as I am acquainted with thorn, been detailed in the preceding Chapter. These experiments prove, as might have been expected, that the peculiar juices diH'er very considerably from each other, and that every plant has a juice peculiar to itself. Hence it follows, that the processes which go on in the leaves of plants must differ at least in degree,, and that we have no right to transfer the conclusions deduced from experiments on one species of plants to those of another species. It is even pro- bable, that the processes in different plants are not the same in kind; for it is not reasonable to suppose, that the phenomena ot vegetation in an agaric or a boletus are precisely the same as those which take place in trees and in larger vegetables, on which alone experiments have hitlierto been made. The true sap is conveyed to every part of the plant ; and all the substances which we find in plants, and even the organs themselves by which they perform their functions, are formed from it. But the thickest veil covers the whc/le of these processes ; and so i'ar have philosophers hitherto been from removing this veil, that tliev have not even been able t • approach it. All these operations, in- deed, are evidently chemical decon. positions and combinations ; but * Nicliolsoii's Jour. x. 289. f Knight on the Inverted Action of tiie Albumens Vessels of Trees. I'ii Trans. 1800. liKCAY OF PLANTS. ^ve neither know what fh„. , ' '^^r f-ssels of Trees. I'liil. CHAPTER VIIJ. "P THE DECAY r»n ^t-Al oj, PLANTS. Such, as far «.« T produced by ve-^etat on"' ^''^"^'"ted with them, are fh. ^ plants at the end of fJ, "^""^ '"'^eed does nnf I, ' '* '^''^ season, or even fl i "^ '^'"'^ ^""0. Some iL , 'T^'" *° ^^^ three, otl e s a htd'rol"''' P^'^^^'' ^^l'- ve t vo't '"' " ^'r^'^^" continue to vo^Sp f "^^ ,'"''^'' ''^"'l there a,-e son," I"""'' ^''"^''^ all cease to Ye : l^^^n T"' ^'^^^^ ^ ^'t L^ J^/;^:;'^^^^ powers which ?..wi ^"^n those very chemioi,! \i ''"er tliey ^t cannot be difficult to di cover \n ^^"^^''"tes the life of a ^jj^f Now, the phenomena of vc^ eta^p'i? '^""^^^^"^^^ 'ts dea li ' u ceases to veiypfnfr. ,.,^ i ''^o'-'^'tie, we sav flnf u i; . Tl>e life c>v "etawLT''''''''-' "M" " i^ dea-d " '""^' '^''"' f [ i ''* if I.*' 1' ! U^' I I if ''I'll. (i /.-I. 1008 DECAY OF PLANTS. a vegetable is dead, it soon changes its appearance, and falls into decay. Thus it appears that the life of a vegetable consists in two things: 1. In remaining unaltered, when circumstances are unfavourable to vegetation ; 2. In exhibiting the phenomena of vegetation, when circumstances are favourable. When neither of these two things lia])pens, we may say that a vegetable is dead. The phenomena of vegetation have been enumerated above. They consist in the formation or expansion of the organs of tlio plant, in the taking in of nourishment, in carrying it to the leaves, in digesting it, in distributing it through the plant, in augmentiiin- the bulk of the plant, in repairing decayed parts, in forming new organs when they are necessary, in producing seeds capable of being converted into plants similar to the parent. The cause of these phe- nomena, whatever it may be, is the cause also of vegetable life, iiiul may be distinguished by the name of the vegef.ativc principle. Hut an inquiry into the nature of this principle belongs to the science of physiology, and would be foreign to the nature of this work. The death of plants, if we can judge from the phenomena, h owing to the organs becoming at last altogether uniit for ])erf()rm- ing their fiuictions, and incajjable of being repaired by nny of tlie powers which the vegetative principle possesses. From the experiments of M. F. Marcet, it ap))cars that metallic poisons act upon vegetables nearly as on animals. They are ab- sorbed, conveyed to the difl'vent parts of the plants, and alter or destroy the tissue. The vegetable poisons which, in animals, act on the nervous system, as opium, nux vomica, menispernnnn coccidus, prussic aciil, belladonna, alcohol, and oxalic acid, also cause the death of plants. Does not this favour the opinion of those who believe, that there is something in plants analogous to the nerves of animals?* * Mem. tie In Societe Naturelle du Geneve, iii. 37. ICO, and falls into lists in two things: unfavourablo to vegetation, wiicn these two things lumeratod above, the organs of tlio g it to the leaves, nt, in augmenting j, in forming now 3 capable of being :ause of those i)ho- vegetable life, nnd fc priuniplc. Hut s to the science of this work, he phenomena, is unfit for perform- I'od by any of tlio icars that metiillic Is. They are ab- ants, and alter or !t on the nervous nhis, prussic acid, le death of plants, ievo, that there is imals?* iii. 37. 1009 DIVISIONT IV. OP THE DECOMPOsiTfnv ^" ™^in- ftr-^ '-^^^^^^^ ^-ourablocircuZt^t'^f -'"=-; '"'•' v o^ 'j ;;'"1 vegetable ';'"f;lage,assumes in he X ^' •^'«""Sr plant l.as^l e ,,0 "T'"'' frii't is an acid in , ^ • ^''^ P'*operties of .f.,.. i J '^'P'^''t'^'s of "JJy '•umu-ng into on? ; 7''"'^' "^ ^''« ^^ pl u t .f'^' ^^'"'"^'P'^'^S -^^S the'rl?' '^--"position t/t^*"""^ ^^eha,S;ft If ffoei on With en n' '' ^7 "'^ '"^'''^"-^ coVfiLi n H '' r ^■'^^^^^^^'^' ^•- ^'- livj;^ p tr'^Tif'T '^ ''- ^^ ")^r;s^^ ^"-- ''^'"^« tL;;2 S''^''''':^''^"^''''^^'^^tre.'en^M \" which the ""'"'aiiz^rrT -^'T''^ l''"-^»'H', that : " ";^"''"^^' '"'-^tter: dero-oos Z'nni '' ^''^ ^--^-^^ witl ,lir' '"^■''^'''^^ nvG more ,,., . ,,. 7 '^'^ « fonnerly „„ite,|, ,„d ^^'^' f ' ^ '"^"'"^r from th*at in Miat of t^H ohl , '''' "'^"" ^»'"]'0'n„ s s ,lt? " "^^^''^'^^I f^'^t the h''^^ '"• V Pou 7!^' 1'""'^^ "f them s ;i v'r' t^^y' ^'^^^ than Mm lOlU DFXOM POSITION OF VEOETAM i,E UDUSTANCES. taneous decomposition Ih caWctl putrefaction ; hut when tlie odour is not ofVonsive, or when imy of the new compouiids formed is ■•j[)j>iin(l to uacful purposes, the spontaneous dccouij)08ition is calledyt' .nei.ta- tion. This word was first introduced into fiicniistrv h^ Van Helnv'Mt.* It is sujipostd l»y some to have orif^Muatc from the intcsti • motion which is always perceptihle wliile vegotahle suh- stanccs are fermentiiif? ; whih) hy others U !>' derived from the heat which in these cases is always ^cncratei'-. Tho term Jcrmenta/ ion is now very oflcn applied to all tlie spontaneous changes which veiTctablc bodies undersro without royard to the products, It there- fore, in that sense, includes pntrefacfion ; aiul certaudy there h no impropriety in thus extending the term so as to make it comprehend every case of spontaneous decomposition, l^y fermentation, then, is now meant all tho spontam»ous changes whici\ take place in vegeta- ble substances after hey arc separated from the living plant. All the phenomena of fermentation lay for many years concealed in the completest darkness, and no chemist whs bold enough to hazard even an attempt to explain them. They were employeil, however, and without hesitation ton. in the explanatinu of other phenomena; as if giving to one process the name of another, of which we are tNpially ignorant, could, in reality, add any thing to our knowledge. The darkness which enveloped these phenomena has begun to disperse ; but tlu'y an; still surrounded with a very thick mist ; and wo must be much better acquainted with the composition of vegetable substances, and the mutual athnities of their ingredi- ents, than we are at present, before we can explain them in a satis- factory manner. S« °ro» In l,"-"' """'"f"'^- * written abJu 'S;%:S f,™ «- °" 'helZ;" .tl r""'"'^-* ■ ".ii^- . ' f J ." ill! i II I i 11 S'f 1 'r IMAGE EVALUATION TEST TARGET (MT-3) /. ^O 1.0 I.I 1^ 128 |25 ■^ lii 12.2 1^ IU£ 12.0 iJ& L25 1 U. 16 ^ 6" ► fliotographic Sciences Corporation '^;*^l^^ 23 WEST MAIN STREET WEBSTER, N.Y. MS80 (716) S72-4S03 'V' .V ^i^ 4b> <° 1012 VINOUS FERMENTATION. as employed in Spain, under the names of calia and ceria, and in Gaul under the name of cervisia.* Almost every species of corn has been used for the manufacture of beer. In Europe it is usually made from barley, in India from rice ; in the interior of Africa, from the seeds of the holcus spicahts.^ But whatever grain is employed, the process is nearly the same. But as grain in its natural state does not answer so well for making beer, it is usual in the first place to convert it into malt. I. Malting. The term malt is applied to grain which has been made to germinate artificially to a certain extent, after which the process is stopped by the application of heat. The barley is steeped in cold water for a period which (as re- gulated by law) must not be less than 40 hours ; but beyond that period the steeping may be continued as long as is thought proper. Here it imbibes moisture, and increases in bulk ; while at the same time a quantity of carbonic acid is emitted, and a part of the sub- stance of the husk is dissolved by the steep-water. The'proportion of water imbibed depends partly on the barley, and partly on the length of time that it is steeped. From the average of a good many trials, it appears that the medium increase of weight from steeping, may be reckoned 0-47 ; that is to say, every 100 pounds of barley when taken out of the steep weigh 147 pounds. The average increase of bulk is about a fifth; that is to say, that 100 bushels of grain, after being steeped, swell to the bulk of 1 20 bushels. The carbonic acid emitted while the barley is in the steep is inconsiderable ; and it is probable from the expctiments of Saussure, that it owes its formation, at least in part, to the oxygen held in solution by the steep-water. The steep-water gradually acquires a yellow colour, and the peculiar smell and taste of water in which straw has been steeped. The quantity of matter which it holds in solution varies from j^^th to jcjjth of the weight of barley. It consists chiefly of an extrac- tive matter of a yellow colour and disagreeable bitter taste, which deliquesces in a moist atmosphere, and contains always a portion of nitrate of soda. It holds in solution most of the carbonic acid dis- engaged. This extractive matter is obviously derived from the husk of the barley, and is that substance to which that husk owes its colour. Accordingly grain becomes much paler by steeping. After the grain has remained a sufficient time in the steep, tlie water is drained ofl', and the barley thrown out of the cistern upon the malt-floor, where it is formed into a rectangular heap, called the couch, about 16 inches deep. In this situation it is allowed to re- main about 26 hours. It is then turned, by means of wooden shovels, and diminished a little in depth. Tliis turning is repeated twice a- day or oftener, and the grain is spread thinner and thinner, till at last its depth does not exceed a few inches. When placed on the couch it begins gradually to absorb oxygen Pliiiii Niit. Hist. lib. xxii. c. 25. f Park's Tiiivcls, p. 63, 8vo Edition. BEER. 1013 , and ill ufacturc i\a from picatus.] lie same, r making has been ivhicb the ch (as re- yond that ht proper, t the same )f the sub- proportion rtly on tbe good many m steeping. Is of barley ige increase Is of grain, ;he carbonic erable; and I it owes its jtion by tbe ur, and the een steeped. is from y^tb : an extrac- taste, wbicli a portion of nic acid dia- led from tbe tt busk owes steeping, le steep, the cistern upon Ip, called tbe [lowed to re- ,den shovels, ited twice a- inner, till at Uorb oxygen from the atmosphere, and to convert it into carbonic acid ; at first very slowly, but afterwards more rapidly. The temperature, at first the same with that of the external air, begins slowly to increase ; and in about 96 hours the grain is, at an average, about 10° hotter than the surrounding atmosphere. At this time the grain, which had become dry on the surface, becomes again so moist that it will wet the hand, and exhales at tbe same time an agreeable odour, not unlike that of apples. The appearance of this moisture is called sweating. A small portion of alcohol appears to be volatilized at this period. The great object of the malcman is to keep the tem- perature from becoming excessive. This they do by frequent turn- ing. The temperature which they wish to preserve varies from 55° to 62°, according to tbe different modes of malting pursued. At the period of the sweating the roots of tbe grains begin to appear, at first like a small white prominence, at the bottom of each seed, which soon divides itself into three rootlets, and increases in length with very great rapidity, unless checked by tui-ning the malt. About a day after the sprouting of the roots, the rudiments of the future stem, called acrospire by the maltsters, may be seen to lengthen. It rises from tbe same extremity of the seed with the root, and advancing within the husk, at last issues from the opposite end : but the process of malting is stopped before it has made such progress. As the acrospire shoots along tbe grain, the appearance of the kernel, or mealy part of the corn, undergoes a considerable change. The glutinous and mucilaginous matter is taken up and removed, the colour becomes white, and the texture so loose that it crumbles to powder between the fingers. The object of malting is to produce this change : when it is accomplished, which takes place when the acrospire has come nearly to the end of the seed, the process is stopped by drying the malt upon the kiln. The temperature at first does not exceed 90° ; but it is raised very slowly up to 140°, or higher, according to circumstances. The malt is then cleaned, to separate the rootlets, which are considered as injurious. Such is a short sketch of the process of malting. Barley, by being converted into malt, generally increases two or three per cent, in bulk ; and loses, at an average, about a fifth of its weight, or 20 per cent. But of these 20 parts 12 are to be ascribed to kiln-dry- ing, and consist of water, which the barley would have lost had it been exposed to the same temperature : so that the real loss does not exceed eight per cent. From a good many trials, made with as much attention to all the circumstances as possible, the following seems to be the way of accounting for this loss : — Carried off by the steep-water . . 1*5 Dissipated in the floor . . . 3'0 Roots, separated by cleaning . . 3*0 Waste 0*5 ■i lit m 8vo Edition. 8-0 1014 VINOUS FERMENTATION. The loss 011 the £oor ought to be entirely owing to the separation of carbon by the oxygen of the atmosphere ; but were this the only cause, it would be much smaller than three per cent. Two other causes concur to produce this loss : — 1. Many of the roots are broken off during the turning of the malt ; these wither and are lost, while others grow in their place : — 2. A certain portion of the seeds lose the power of germinating, by bruises or other accidents, and these lose a much greater portion than three per cent, of their real weight. From a good many trials, made with as much care as possible, I am disposed to conclude that the quantity of carbon, separated during the whole process of malting, by the formation of carbonic acid gas, does not exceed two per cent, and that the weight of the roots formed amounts often to four per cent. These two, in reality, include the whole real loss of weight which barley sustains when malted. What is lost in the steep, being husk, need scarcely be reckoned. The roots appear, from the process, to be formed chiefly from the mucilaginous and glutinous parts of the kernel. The starch is not employed in their formation ; but undergoes a change, intended no doubt to fit it for the future nourishment of the plumula. It acquires a sweetish taste, and the property of forming a transparent solution with hot water. In short, it approaches somewhat to the nature of sugar, and is probably the same with the sugar into which starch is converted, by boiling it with diluted sulphuric acid. Malt thus prepared is ground in a mill, and infused in a large cylindrical vessel called the mash tun, with somewhat more than its own bulk of water, of a temperature varying from 160° to 180°, ac- cording to the fancy of the brewer. The infusion is left covered for two or three hours, and then the liquid drawn off by a cock at the bottom of the vessel. "* " q hot water is afterwards added, and the infusions repeated in a ar manner till the malt is sufficiently exhausted. The liquid thud ootained, is called wort. II. Wort. rfbr< has a brownish-yellow colour, a luscious sweet taste, a peculiar smell, and when the process is properly conducted is perfectly trar? ^iarent. It consists of the water employed holding the mealy part of the malt in solution. When examined by reagents, it appears to consist chiefly of four different substances held in solu- tion together: namely, I. A sweet-tasled substance, to which the name of saccharine matter has been given. It is by far the greatest in point of quality. This substance when separated has a light- brown colour ; when dried at 160°, it forms a brittle mass with a glazed surface ; at the temperature of 180°, or a little higher, its colour becomes darker ; and if we keep it in that temperature, moistening it occasionally, it becomes at last almost black, loses its I sweet taste altogether, and acquires a sharp disagreeable one. In a temperature somewhat higher, but under the boiling point, it is charred. It is very soluble in water, and if once dissolved can scarcely be recovered again by evaporation without considerable loss. Alcohol dissolves it very imperfectly cold, and when heat is I '' BEER. 1015 eparation J the only 'wo other roots are i are lost, f the seeds dents, and their real ch care as of carbon, jrmation of D the weight lese two, in ley sustains sed scarcely efly from the starch is not intended no It acquires irent solution the nature of which starch 3d in a large more than its |o to 180°, ac- is left covered by a cock at Ids added, and is sufficiently applied it deprives the alcohol of a portion of water, and forms a tough mass like turpentine, which refuses to dissolve. The specific gravity of this saccharine matter is 1'552. It appears to be the essential constituent of wort. 2. Starch. The presence of this substance is easily detected by dropping the infusion of nutgalls into wort ; a precipitate appears, which is mostly redissolved by heating the liquid to 120°. 3. The insoluble part of the precipi- tate is a combination of albumen and tannin. The proportion of gluten in wort is very inconsiderable. That of the starch probably diminishes in proportion as the barley is more completely malted. I have detected starch in pretty old and perfectly transparent ale ; but the gluten had disappeared. New ale, however, often contains traces of it. 4. The fourth ingredient in wort is mucilage^ which precipitates in flakes when the wort is dropped into alcohol. Its quantity is more considerable in the worts last drawn oft' than in the first worts. The wort is boiled with a quantity of hops, which vary consider- ably, but which may be stated in general at about ^gth of the weight of the malt. III. Hops. Hops are the cones of the female flowers of the Humulus lupulus, a dioecious plant belonging to the family of urticecB. An account of the chemical nature of hops, so far as it has been investigated, has been given in a preceding Chapter of this volume. The use of the hops is partly to communicate a peculiar flavour, from the oil which they contain ; partly to cover the sweetness of saccharine matter by the bitter principle which they contain ; and partly to counteract the tendency which wort has to run into acidity. IV. Fermentation. When the wort is sufficiently concen- trated, it is thrown into very wide flat vessels called coolers, placed in the most open situation that can be had. Here it is cooled down to the temperature of about 52°, and then let down into a deep round wooden vessel called t\ie fermenting tun. The specific gravity of the wort when put into the fermenting tun varies very much. The wort of strong ale is sometimes as low as 1*060 ; sometimes as high as 1'127. In the first case it contains 14*25 per cent, of solid matter ; in the second 28*2 per cent. The wort of smal) beer varies from 1*015 to 1*040 ; the first containing not quite 3*5 per cent, and the second about 9*5 per cent, of solid matter. If the wort be let down into the fermenting tun at the tempera- ture of 60°, or rather higher, the substances which it holds in solution begin gradually to act upon each other, and to decompose each other. The temperature rises, an intestine motion takes place, a scum collects on the surface, and carbonic acid gas is emitted. This intestine motion is called fermentation. The dis- position of wort to ferment is not sufficiently great to induce it to do so with the requisite rapidity. It takes place so slowly and im- perfectly, that the liquor runs into acidity before the formation of ale has made sufficient progress. To prevent this, it is requisite i!f I'ir 1 * ' ,11 1' 'Mi IP *•' ill »l. 1016 VINOUS KEIIMENTATION. to add to the wort some substance which has the property uf induc- ing speedy fermentation. The substance made choice of is yeast, or the frothy matter which collects on the surface of the beer while fermenting. The quantity of yeast used by brewers is but small, generally about a gallon to every three barrels of tho wort. The yeast thus added acts upon the saccharine matter held in solution in the wort and decomposes it while it undergoes partial decomposition itself. By this mutual action the saccharine matter disappears, the specific gravity of the wort diminishes, and its pro- perties alter, being converted into the intoxicating liquor called ale. During this mutual action the temperature of the liquid increases, and the increase depends upon the violence of the fermentation. In ale worts the rise of temperature is but small, amounting at an average to about 15°, because the quantity of yeast is small; but in the fermentation of wash, it often amounts to 50°, or even more in some cases. Considerable exertions have been made by chemists to ascertain the nature of the substance in yeast which produces this striking effect upon wort, and to discover it if possible in other substances. Westrumb examined the yeast of beer. From 153G0 parts of it he obtained the following substances Potash Carbonic acid Acetic acid Malic acid Lime Alcohol Extractive . Mucilage Saccharine matter Gluten Water u 13 15 10 45 69 240 120 240 315 480 13595 15142 Besides some traces of phosphoric acid and of silica.* But it is obvious, that all these ingredients are not essential. From the ex- periments of Westrumb, it appears that when the yeast is filtered, a matter remains upon the filter which possesses the properties of gluten ; that when this substance is separated the yeast loses the property of exciting fermentation, but recovers it again when the gluten is added. Hence it follows that this glutinous matter is the essential constituent of the yeast. When yeast is kept for some time in cylindrical glass vessels, a white substance not unlike curd separates and swims upon the surface. If this substance be removed the yeast loses the property of exciting fermentation. This sub- stance possesses many of the properties of gluten, though it difl'ers from it in others. Its colour is much whiter, it has not the same * Crell's Annals, 1796, i. l;3. BBRR. 1017 pxygcn to consume it. Nitrir?,nS ""'"'"".S H time its bulk „f "to a species of ullow. W h w i ?™" "hen diluted, converts it ie/Sa"" •'«-™- »ib Tf *° J--."' 'ofes' ife- Xie' nxea with a new portion of suo-.,,. * ^f^^^'n^ fermentation vhen hrows considerable light on thSV ^" ^^P^riment of Kirchoff tarns both gluten anS sta Tel " "I^"/r"^ k ^^^^^^^^^ jater i ,s not converted into suAr M • i^'"^'' ''^ ^"^"sed in hot cchanne matter when treated if tie s^e'" '%^^"*- ^-oZ infn^P^l- t'^^' pulverized wheat Itn 7" ^"^ ^^ a mixture nlused in hot water, the starn . ;! ^ " ^'"^ P^tatoe starch hi "•e process an acid s evolved '^^r'''']''^^^ into sugar. DuHn ' P^-nce^ and if the U^^'^^ t^^^'^ altered inTp! f'^nce connected with The ite^^fT ''^'" *^^^* ^^ ''« «on e sub! I ^°n^verts it into sugar.f ^ "*'" ''^"' ^^^^ "Pon the starch, and I f te.;! "Cn nSd witHh; tS ^ ^--i^ered as altered r^acchanne matter,- the temn^J ' ^"' ^"bstance acts upon he h< and the sacihaHnl'SM: ZT' f^"- -'^ i^'d^ „! 11 1018 VINOUS FBHMBNTATION. yeast soon collects on the top of the liquid, but the brewer occn- sionally mixes it again to continue the fermentation. The quan- tity of veast employed being small, the saccharine matter is but im- perfectly decomposed. Hence a considerable portion of it still remains in the ale, and gives it that glutinousness and body for which it is remarkable. The specific gravity of the ale varies very much according to the original strength of the wort, and the extent to which the fermentation has been carried. The limits may be stated at about 1*035 and 1*012. The properties of ale are so well known, that no description is deemed necessary. It possesses intoxicating qualities, and holds a quantity of alcohol in solution ; which varies considerably accord- ing to the original strength of tne wort. I distilled a quantity of London-brewed ale. The specific gravity of the wort was 1*0676. The specific gravity of the ale was 1*0255. One hundred parts of it by weight yielded 9*354 parts of proof spirit of specific gi'avity . 0*91985 Or, 5*817 parts of alcohol of the specific gravity . 0*825 Another specimen of ale was distilled. The specific gravity of the wort was 1*0813. The specific gravity of the ale after fermen- tation was 1*02295. One hundred parts of it by weight yielded 11*13 parts of proof spirit 6*92 parts of alcohol of the specific gravity 0*825. Mr Brande* distilled ale and brown-stout porter. The quan- tity of alcohol which he extracted from each by measure was as fol- lows : — Brown stout . . 6*80 per cent. Ale . . . . _ 8*88 When reduced to weight, the quantity of alcohol of the specific gravity 0-825 obtained from each, will be as follows : — Brown stout . . 5*61 per cent. Ale . . . . 7*33 V. Wash. Ale being intended as an article of food, and its value depending in a great measure on its flavour and appearance, particular attention is paid to obtain these in as great perfection as possible. But there is another species of ale which is brewed by the distillers, for the express purpose of procuring from it ardent spirits by a subsequent process. The method which they follow is in several respects different. In particular, they endeavour to carry the fermentation to as great a length as possible, because the quantity of spirits is proportional to the saccharine matter decom- posed, whatever remains unaltered yielding none. It is here, j therefore, that the effects of fermentation can be best observed. 1. In this country the distillers do not brew from pure malt; I they use also raw grain. The proportion of malt varies from a third to a tenth part of the raw grain employed. This mixture] • Phil. Trans. 18U, p. 346. BEEll. 1019 t i'v,; er occa- ,e quan- but ira- • it stUl body for ties very tie extent 3 may be •ription is d holds a ly accord- luantity of as 1-0676. ed parts of •91985 i'825 c gravity of fter fermen- it yielded 25. The quan- e was as fol- the specific they grind to meal, infuse with water at a heat considerably lower than that of the water used by the brewers, and employ much more agitation to mix it completely. The wort is drawn off and cooled in the usual way, and fresh water poured on to exhaust the grain. The wort thus formed is not so transparent as that from malt, but its taste is nearly as sweet. It would appear, therefore, that the starch in the raw grain undergoes a certain change during the mashing, and is brought towards the state of saccharine matter. In this country, where the duty is levied chiefly upon the washy* the distillers make the specific gravity of their wort as high as from 1*084 to I'llO: this they do, not by boiling, but by lobbing, that is, by preparing a strong infusion of the flour of malt, or of barley, and malt, and hot water, and adding this almost saturated solution to the wort, till it has acquired the requisite strength. But in Hol- land, where the duties are levied in a different way, the specific gravity of the wort is much lower. Some years ago, the very improper regulations to which the dis- tillers in this country were subjected, were very much altered for the better. The distillers were allowed to use wash of any specific gravity which they thought would answer best. They were not obliged, as heretofore, to produce a given quantity of spirits out of every hundred gallons of wash : the duty on malt was so much diminished, that it became the interest of the distillers to employ malt instead of raw grain. The consequence of these changes is, that malt is now commonly used for making spirits in Scotland : the wash is so much weaker than formerly, that the fermentation is more complete, and a greater quantity of spirits is obtained from the same quantity of grain than formerly, and the flavour of the spirits is very much improved. The wort thus made is let down into the fermenting tun at a temperature varying from 55° to 70°, accordinir to the quantity, the season, the goodness of the yeast, and the :^ -Ul of the distiller. Here it is mixed successively with considerable jortions of the best yeast that can be procured, and the fermentation is urged as far as it can be made to go. The process lasts about ten days, and the temperature rises usually to between 90° and 100°, and sometimes even higher. Great quantities of carbonic acid are disengaged, and the liquid becomes specifically lighter ; sometimes sinking to l"000, and usually to from 1*007 to 1-002. The success of the fermentation is estimated by this loss of specific gravity. The wash thus prepared is distilled. What comes over first is denominated low wine, and is concentrated by a second distillation. This fermentation is obviously the consequence of the action of the peculiar ferment in yeast upon the saccharine matter of the wort. Even when the fermentation is carried to its greatest extent, it does not appear that the whole solid matter held in solution by Ill's. M f:| ,f< m\ ill !l r h. I- • This is the name given to the fermented wort of distillers. I»': in m m 1020 VINOUS FEIIMRNTATION. I I the wort ia decomposed. Nine trials were made upon the wort of pure malt ; in all of them the fermentation went on ])rotty success- fully, as may be seen from the following table : — Sperlflc grnvity 8|>r('inc gmvlljf of tliu wort. Dfllu' Wiuh. 1-0400 1-0014 1-0560 1-0016 1-0500 1-0000 1-0492 1-0012 1-04(55 i-ooia 1-0450 1-0047 l-04t)5 1-0007 1-0510 1-0007 1-0524 1-0004 When a portion of these different liquids was evaporated to dry- ness, the quantity of solid matter which it left was found to amount to ^th, at an average, of the original quantity. Thus ^^ths had been decomposed by the fermentation, and }th still remained. This matter was still capable of fermentation, when redissolved in water and mixed with fresh yeast. On comparing the quantity of alcohol of 825, obtained in these trials, with the weight of solid matter of the malt which had been decomposed by the fermentation, the result was, that every pound weight of solid matter, so decom- posed, furnished almost exactly half a pound of alcohol, of the spe- cific gravity 0-825. When sugar, dissolved in four times its weight of water, and mixed with yeast, is placed in the proper temperature, it ferments pre- cisely as wort does, and yields the same products. It has been employed, therefore, by chemists as a less complicated moans of ascertaining the phenomena of fermentation. Thenard mixed 60 parts of yeast with 300 of sugar, and fermented them in the tem- perature of 59°. In four or five days, he informs us, that all the sac- charine matter had disappeared.* The quantity of carbonic acid evolved amounted, by weight, to 94-6 parts. It was perfectly pure, being completely absorbed by water .f The fermented liquid, being distilled, yielded 171-5 parts of alcohol, of the specific gravity -822. When the residue of the distillation were evaporated, 1 2 parts of a nauseous acid substance were obtained; and 40 parts of the yeast still remained ; but, upon examination, it had lost the whole of its azote. This experiment gives us the following quantities : — * There is reason to doubt the precision of this assertion, as it never happens ill the great scale, where every thing is much more favourable. t The very pungent aromatic odour which curbonic acid has when disengaged from the fermenting tun, shows that it contains a portion of the wash ; and this has been verified by actual experiment. Gay-Lu.«sac has shown the quantity of alcohol carried off during the fermentation of wine. Sec Ann. do Chim. ct dc I'll vs. xviii. 380. ! wort of 8UCCCSS- I . Substances fcnncnted. Sugar . Yoast . 300 00 IP 1021 300 ted to dry- . to amount 3 ^ths bad remained, dissolved in quantity of rrbt of solid Brmentation, r, 90 decom- , of tlie spe- ;r, and mixed srments pre- It has been jd means of tvd mixed 60 in the tem- ,t all tbe sac- ;arbonic acid Irfectly pure, liquid, being gravity "822. K2 parts of a of tbe yeast wbole of its Ities : — , never happens ihen disengaged Iwash ; and this 1 the quantity ot Lie Chim. clilc 2. Proihicts of fermentation. Alcohol of -822 . . 171-5 Carbonic acid . . . 94-0 Nauseous residue . . 12-0 Residual yeast . . . 40-0 Loss 318-1 41-9 But as the nauseous residue and residual yeast, nearly make up the quantity of yeast employed, let us consider only the products of decomposed sugar, supj)osing the loss to be proportionally divided between the carbonic acid and alcohol. Now, alcohol or the spe- cific gravity 0-822 contains jVyth of its weight of water, which can be separated from it ; and if >vo suppose, with Saussure, that absolute alcohol contains 8-3 per cent, of water, then the products of sugar decomposed by fermentation, according to the preceding experiment, are as follows : — Alcohol .... 47-70 Carbonic acid . . . 35-34 Or, in 100 parts Alcohol . Carbonic acid 83-04 57-44 42-50 100-00 This result approaches so nearly that of Lavoisier, that there is reason to suspect that the coincidence is more than accidental. We have found reason to conclude, that sugar of starch is com- posed of 9 atoms oxygen . . = 9-000 8^ atoms carbon . . . = 0-375 9 atoms hydrogen . . =1-125 10-500 Alcohol is a compound of 1 atom oxygen 2 atoms carbon . = 1-000 = 1-500 3 atoms hydrogen = 0-375 * I* • 15. .i 2-875 1022 VINOUS FKHMBNTATION. And carbonic acid of 2 atoma oxygon 1 atom carbon = 2-00 = 0-7fi 2-7fl Now, if wo euppoflo 1 atom of sugar to bo decomposed by the fermentation, it is obvious, that they may be converted into 3 ntoina of alcohol and 3 atoms of carbonic acid. For an atom of sugar is composed of . . . . . . C* H* ()* 3 atoms of alcohol consist of . . . C* H" O' 3 atoms of carbonic acid of ... C 0° Making together ..... C» H» O" On that supposition, the weight of the alcohol evolved ought to bo . 5«7.'i And that of the carbonic acid . 5'50 Or, per cent. Alcohol 5112 Carbonic acid 48-88 100-00 Fabroni found that the gluten of wheat acted but imperfectly as a ferment ; but that its ofBcacy was much improved by tno addition of tartar. I^crthollet repeated these experiments successfully. He ascribes the efficacy of tartar to the property which it has of pro- moting the solubility of the gluten. The presence of an acid was supposed formerly to be necessary for fermentation ; but this does not seem to be the case. It is true, indeed, that an acid usually makes its appearance during fermentation. The formation of this acid has been ascribed to the action of the yeast upon the mucilagi- nous or starchy parts of the wort; but from the experiments of Fourcroy and Vauquclin, it appears that it always makes its appear- ance when wort is fermented without any yeast. In these trials they obtained only vinegar, and no alcohol. When the wort, either of raw grain or of malt, is fermented at the temperature of 80°, without any yeast, the gas which comes over consists of one-half carbonic acid and one-half hydrogen ; but at a lower temperature, pure malt-wort does not yield any inflammable gas.* SECTION II. — OF WINE. There is a considerable number of ripe fruits from which a sweet liquor may be expressed, having at the same time a cer- tain degree of acidity. Of such fruits we have in this country the apple, the cherry, the gooseberry, the currant, &c., but by far the most valuable of these fruits is the grape, which grows luxuri- antly in the southern parts of Europe. From grapes, fully ripe, may be expressed a liquid of a sweet taste, to which the name of * Aim. dcs Mus. d'Hist. vii. 16. M'INI. 1023 Bd by the a 3 ntoins f gugar U « ()» ►•50 jperfectly as the addition asfully. He t lias of pro- an acid was )ut this does acid usually lation of this khe mucilagi- Iperiments of ' IS its appear- these trials , wort, either ^ture of 80°, 9 of one-half [temperature, rora which a time a cer- Ithis country ];., but by far ^rows luxuri- es, fully ripe, the name of muat has been given. This liquid is composed almost entirely of five iiij^redients ; namely, water^ sttgar^ j^^lfy gluten^ and tartaric acid partly saturated with potash. The nuantity of sugar which grapes, fullv ripe, contain, ia very cunsideraule ; it may be obtained in crystals by evaporating must to the consistence of syrup, separat- ing the tartar which precipitates during the evaporation, and then setting the muat aside for some months. The crystals of sugar are gradually formed.* From a French pint of must^ the Marquis do Houillon extracted half an u\\u"Xi (French) of sugar, and ^'^th ounce of tartar.f According to Proust, the liluscadino grape contains about 30 per cent, of a peculiar species of sugar.t When muat is put into the temperature of about 70°, the ditFerent Ingredients begin to act upon each other, and what is called vinous fermentation commences. The phenomena of this fermentation are an intestine motion in the litiuiu ; it becomes thick and muddy, Its temperature increases, and carbonic acid gas is evolved. In short, the very same changes take place as have been remarked when describing the fermentation of ale. In a few days the fermeiitiition ceases, the thick part subsides to the bottom, or rises to the sur- face, the liquid becomes clear, it has lost its saccharine taste, and assumed a new one ; its specitic gravity is diminisheu , and it has become the liquid well known under the name of wine. As this fermentation takes place without adding any ferment, it is obvious that the requisite substance is present in tlie juice. This substance was separated, and found by (abroni to be analogous to the gluten of plants ; and gluten being substituted for it, the fer- mentation succeeded. Fabroni has shown that the saccharine part of muat resides in the cells of the grapes ; while the glutinous mat- ter, or ferment, is lodged on the memoranes that separate the cells. Hence it follows, that in the fruit these two substances are not in contact. It is only after the juice is squeezed out that they are mixed. All other juices which undergo a spontaneous fermentation at the requisite temperature, have been shown by Thenard and Seguin to contain a similar substance. The formation of wine, then, is owing to the action of this glutinous matter on the saccha- rine substance of the juice, precisely as happens in the fermentation of ale. Gay-Lussac has shown that the juice of grapes, and indeed the juice of all fruits will not ferment, if completely excluded from the air. But if a little oxygen gas be let up to it, this gas is immediately absorbed, a brisk fermentation commences, and the quantity of car- bonic acid gas evolved is 100 times as great as that of the oxygen gas absorbed.§ It would be curious to know whether the same thing holds with repect to the wort of malt. It is not improbable that it does ; but wort ferments so imperfectly without the addition of yeast, that it would not be easy to try the experiment. I I 1 i Ilk ' il ! i' I til 11 m\, * Bouillon, Jour, de Phys. xxix. 3. f Ibjil. p. 5. § Ann. dc Chim. Ixxvi. 245. X Ibid. Ivi. ll.-). t U 1024 VINOUS FERMENTATION. All those juices of fruits which undergo the vinous fermentation, either with or without the addition of sugar, contain an acid. We have seen already that the vegetable acids are obtained chiefly from fruits. The apple, for instance, contains malic acid ; the lemon, citric acid ; the grape, tartaric and malic acids. The Marquis de Bouillon has ascertained that must will not ferment if all the tartar which it contains be separated from it ; but it ferments perfectly well on restoring that salt.* The same chemist ascertained that the strength of wine is considerably increased by adding tartar and sugar to the must.'\ We may conclude from these facts, that the presence of a vegetable acid is of importance in these spontaneous fermentations. It deserves attention, that Bouillon obtained more tartar from verjuice than from wine; and he observed, that the more the proportion of sugar in grapes increased, the more that of tartar diminished. $ It seems more than probable, from the experiments of Bouillon and Chaptal, that the tartaric acid is partly decomposed during the fermentation, and that a portion of malic acid is formed. The pro- cess, therefore, is more complicated than was suspected by Lavoisier. It is obviously analogous to combustion, as is evident from the evolution of caloric and the formation of carbonic acid, which is a product of combustion. Proust has affirmed that, during the fer- mentation, not only carbonic acid, but azotic gas also, is disengaged. This, supposing it correct, is a demonstration that all the consti- tuents of must are concerned; for sugar does not contain that principle.§ Thenard could detect no azote in the carbonic acid from wort. After the fermentation has ceased, the liquor is put into casks, where the remainder of the sugar is decomposed by a slow fermen- tation ; after which the wine, decanted off the extractive matter, is put up in bottles. The properties of wine differ very much from each other, accord- ing to the nature of the grapes from which the must was extracted, and according to the manner in which the process was conducted. These differences are too well known to require a particular descrip- tion. But all wines contain less or more of the following ingrc- dients ; riot to mention water, which constitutes a very great pro- portion of every wine. 1. An Acid. All wines give a red colour to paper stained with turnsole, and of course contain an acid. Chaptal has ascertained that the acid found in greatest abundance in wine is the malic, but he found traces also of citric acid ; and it is probable tlmt wine is never entirely destitute of tartar. All wines which have the property of frothing when poured into a glass contain also car- bonic acid, to which they owe their briskness. This is the case * Jour, de Pliys. xxix. 4. But the addition of salt of wood sorrel did not rcsloro the ferincntation. t Ann. de Ciiini. xxxvi. 'JO. \ .Tour, do I'hvs. xxi\. 'I-. § ibid. Ivi. II:). Wit tior be ( hav 2 whi( of C( undt wine all y sepai had ; wardi alcohi longj obtain part under is disti old.} by the poratec 3. I proport gradual 4. E which p in quant 5. T husk of This ma a set of examine( System the wine cipitates hme-wat( From matter of % this pi or factitio The fo Neumann • Phil. Ti t Ann. de y The mos published, is Ann. de Chit II Annals WINE. 1025 itatlon, I. Wo fly from lemon, rquls de le tartar perfectly ned that irtar and that the (Utaneous led more that the ire that of I Bouillon during the The pro- Lavoisier. t from the which is a Ing the fer- lisengaged. the consti- iontain that rhonic acid into casks, ow fermen- re matter, is her, accord- ,s extracted, conducted. ,lar descrip- Iwing ingrc- trreat pro- istained witli ascertained the malic, l-ohahle tlwt which have xin also car- is the case Idid not restore with champagne. These wines are usually weak ; their fermenta- tion proceeds slowly, and they are put up in close vessels before it be over. Hence they retain the last portions of carbonic acid that have been evolved. 2. Alcohol. All wine contains less or more of this principle, to which it is indebted for its strength ; but in what particular state of combination it exists in wine cannot easily be ascertained. It is undoubtedly intimately combined with the other component parts of wine ; but Mr Brande has shown by very decisive experiments that all whies contain alcohol ready formed, and that it is merely separated during the distillation of these liquids, and not formed as had been advanced by Fabroni.* These experiments were after- wards confirmed by Gay-Lussac.t When wine is distilled, the alcohol readily separates. The distillation is usually continued as long as the liquid which comes over is inflammable. The quantity obtained varies according to the wine, from a fourth to a fourteenth part of the wine distilled. The spirit thus obtained is well known under the name of brandy. Bouillon has observed, that when wine is distilled new it yields more alcohol than if it be allowed to get old.$ What reraaii..' after this distillation is distinguished in France by the name of vinasse. It consists of tartar, &c., and when eva- porated to dryness, and subjected to combustion, yields potash. 3. Extractive matter. This matter exists in all wines : but its proportion diminishes according to the age of the wine, as it gradually precipitates to the bottom. 4. Every wine is distinguished by a peculiar flavour and odour, which probably depends upon the presence of a volatile oil, so small in quantity that it cannot be separated. 5. The colouring matter of wine is originally contained in the husk of the grape, and is not dissolved till the alcohol be developed. This matter is analogous to the other colouring matters of plants : a set of bodies possessed of remarkable properties, but too little examined hitherto to be introduced with much advantage into a System of Chemistry. This colouring matter precipitates when the wine is exposed to the heat of the sun. It sometimes also pre- cipitates in old wine, and it may be easily separated by pouring lime-water into wine.§ From the experiments of Vogel, it appears that the colouring matter of red wine is precipitated greenish-grey by acetate of lead. By this property we can distinguish whether a red wine be genuine or factitious.!' The following table, containing the different substances which Neumann extracted from various wines, is worth preserving : — % • Phil. Trans. 1811, p. 337 ; and 1813, p. 82. + Ann. de Chim. Ixxxvi. 175. % Jour, de Phys. rxix. 6. 5 The most precise account of wine and of the vinous fermentation, hitherto piiblislied, is by Chaptal, and is contained in the 36th and 87th volumes of the Ann. de Chim. II Annals of Philosophy, xiii. 70. 1 Neumann's Chemistry, p. 447. 3u r -'\ it 1 \ f ij '1 m u 1026 VINOUS FERMENTATION. A quart o( Highly recti, fled Spirit, Thick, oily, unctuoua, re. aiiioui matter. Gummy and tnttariins matter. Water. oz. dr. gr. oz. dr. Rr. nz. dr. gr. lb. oz. dr. gr. Aland . . 1 6 00 3 2 00 1 5 00 2 5 3 00 Alicant . . 3 6 00 6 20 1 40 2 2 6 00 Burgundy . 2 2 00 4 00 1 40 2 9 20 Carcassone . 2 6 00 4 10 1 20 2 8 4 30 Champagne . 2 5 20 6 40 1 00 2 8 3 00 French . . 3 00 6 40 1 00 2 8 20 Frontignac . 3 00 3 4 00 5 20 2 4 6 30 Vin de Grave 2 00 G 00 2 00 2 9 00 Hermitage . 2 7 00 1 2 00 1 40 2 7 5 20 Madeira 2 3 00 3 2 00 2 00 2 4 3 00 Malmsey 4 00 4 3 00 2 3 00 2 1 2 00 Vino de 1 Monte > 2 6 00 3 00 2 40 2 8 20 Pulciano j Moselle . . 2 2 00 4 20 1 30 2 9 10 Muscadine . 3 00 2 4 00 1 00 2 5 4 00 Neufchatel . 3 2 00 4 00 1 7 00 2 2 7 00 Palm Sec. . 2 3 00 2 4 00 4 4 00 2 2 5 00 Pontac . . 2 00 5 20 2 00 2 9 40 Old Rhenish 2 00 1 00 2 20 2 8 5 40 Rhenish . . 2 2 00 3 20 1 34 2 9 1 06 Salamanca . 3 00 3 4 00 2 00 2 3 4 00 Sherry . . 3 00 6 00 2 2 00 2 6 00 Spanish . . 1 2 00 2 4 00 9 4 00 1 10 6 00 Vino Tinto . 3 00 6 4 00 1 6 00 2 6 00 Tokay . . 2 2 00 4 3 00 5 00 2 3 00 Tyrol red wine 1 4 00 1 2 00 4 00 2 8 6 00 Red wine 1 6 00 4 40 2 20 2 9 3 20 White . . 2 2 00 7 00 3 00 2 7 00 To this head belong not only common wine, but all the intoxi- cating liquors made from vegetable juices ; as cyder from apples, perry from pears, currant wine, &c., likewise the liquor made from the juice of the sugar cane, the sugar maple, &c. I shall here subjoin a table of the quantity of alcohol by measure of the specific gravity 0*825, which different wines yielded to Mr Brande in his different experiments. The results of these trials are the more valuable, because the wines examined were all gen- 1 uine.' • Phil. Trans. 1811, p. 345; 1813, p. 87. i. 136. Journal of the Royal Institution, in WINE. 1027 20 , 10 i 4 00 2 7 00 2 5 00 9 40 8 5 40 9 I 06 3 4 00 6 00 6 00 6 00 3 00 8 6 00 9 3 20 7 00 all the intoxi- Ifrom apples, lor made from lol by measure lyielded to W ^f these trials | were all gen- loyal Institution, 1/ L ' Fuit Ditto Ditto Ditto Ditto Ditto Ditto Ditto Madeira Ditto Ditto Ditto Sherry Ditto Ditto Ditto Claret Ditto Ditto Calcavella Lisbon Malaga Ditto, kept since 1 Bucellas . Red Madeira Malmsey Madeira Marsala Ditto 666 Alcohul |>rr cent, by measure. 26-00 24-00 21-40 22-30 23-39 23-71 24-29 25-83 21-40 19-00 19-34 21-40 23-93 24-42 18-25 18-79 19-81 19-83 12-91 14-08 16-32 18-10 18-94 17-26 18-00 18-49 18-40 16-40 25-87 17-26 Marsala . Ditto Red Champagne White Champagne Burgundy Ditto White Hermitage Red Hermitage Hock Ditto Vin de Grave . Frontignac Cote Roti Rousillon Cape Madeira . Cape Muschat Constantia Tent Sheraaz . Syracuse . Nice Tokay . Raisin Wine Grape Wine Currant Wine . Gooseberry Wine Elder Wine Cyder Perry Alcohol per cent, by mcuuru. 26-30 25-50 11-30 12-80 14-53 11-95 17-43 12-32 14-37 8-88 12-80 12-79 12-32 17-26 18-11 18-25 19-75 13-30 15-52 15-28 14-63 9-88 25-77 18-11 20-55 11-84 9-87 9-87 9-87 Every body knows that wine has a peculiar smell, by which it is easily known, and by which it is at once distinguished from a mixture of alcohol and water, of the same strength with the wine. This smell is owing to the presence of a small quantity of a pecu- liar substance, analogous in its properties to a volatile oil. It amounts, at an average, to about ^o.uoo^^ P^'*'' °^ *^^^ wine. When a great quantity of wine is distilled, this substance passes over to- wards the end of the distillation. It may be obtained also by dis- tilling the lees of wine, particularly what is deposited at the bottom of the wine casks when the wine begins to ferment. When pure it is colourless. Liebeg and Pelouze have lately examined this sub- stance, with which they were furnished by M. Deleschamps, and they have found it to be a peculiar ethereal liquid to which they gave the name of ananthic ether* An account of the properties and composition of this ether has been given in a preceding Chapter of this volume.f .sr if ,•: ■■'.' 1 5' liV- • m m * Ann. de Chim. et de Phys. Ixiii. 1 13. t See p. U\. 1028 PANAIIY FERMENTATION. CHAPTER II. OF THE P A N A R Y F E R M E N T A T I O N. The method of making loaf bread similar to ours, was known in the East at a very early period ; but neither the precise time of the dis- covery, nor the name of the person to whom mankind is indebted for it, has been handed down to us. That the Jews knew how to make bread in the time of Moses, or above 1600 years before the com- mencement of the Christian era, is evident from the prohibition of the use of leavened bread during the celebration of the passover.* There is no evidence that loaf bread was known to Abraham ; for in his history, cakes are frequently mentioned, but loaf bread, or leavened bread, never. It can scarcely be doubted, that the Jews learned the art of making loaf bread from the Egyptians. The Greeks in- form us, that they were taught the method of making loaf bread by the god Pan. We learn from Homer, that loaf bread was known during the Trojan war. f Pliny informs us, that no bakers existed in Rome till the year 580 after the building of the city, or about 200 years before the commencement of the Christian era. Before that time, bread was made in private houses, and was the business of the woraen.J The only substance fit for making good loaf bread is wheat flour, obtained by grinding the seeds of triticum hyhernmn^ and probably other species of triticum. The nature of the constituents of wheat flour, so far as ascertained, has been stated in a former Chapter of this volume. It is the practice in some places to mix wheat flour with potatoe starch. Such an addition cannot exceed 30 per cent., otherwise the flour would not be fit for making bread. M. Boland, a baker in Paris, has given the following method of detecting the presence of potatoe starch, when thus mixed with flour : — Take about 300 grains of the flour, make it into a paste, and, kneading it under a small stream or thread of water, separate the gluten which remains in the hand. The water falls on a cloth stretched on tlie wide end of a funnel, corked at its narrow end. The cloth retains the gluten, and the water with the starch falls into the funnel. Let the starch subside from the water in the fun- nel, then decant off the water by a syphon or sucker. Let the starch dry : it will be observed to consist of two layers ; the upper- most is grey, and consists of gluten, the undermost of starch. De- tach the dry starch from the funnel without breaking the lump. Take the lowest portion, triturate it with water in a mortar, filter, * Exod. xii. 15. % Plinii Hist. Nat, xviii. cap. 11. Iliad, lib. ix. 1. 216. anc it V pot red, oft tain 1 watf part! varic Ing, quani be all tation glutei bonic every howev tinues and Ia( not be tion of it be hi sesses \ der it d Dough But dough, commen to at lea and bak be forme The I contrivet Instead or barm, addition is not nei. end of tl yeast for against, to the hea to convinc than that _ ence to lea used by th t Plinii ., '•CSoltlto qiiibl PANAUY FERMENTATION. 102'J in the he dis- ited for o make le com- n of the There )r in his eavened learned reeks in- bread by IS known ;s existed or about Before 3 business Iheat flour, probably of wheat Chapter of til potatoe otherwise Id, a baker [e presence Uste, and, [parate the Jkn a cloth ■arrow end. ^tarch falls fin the fun- Let the [the upper- irch. E>e- the lutnp. Irtar, filter, and add a drop of tincture of iodine. If it be potatoe starch, (as it will be, if any be present,) the iodine strikes a fine blue, if no potatoe starch be present, the liquid becomes only yellow or violet red, which soon disappears. By repeating this trial on new slices of the starch, you can determine how much potatoe starch it con- tains.* The process of baking bread consists in mixing wheat flour with water, and forming it into dough. The average proportion is, two parts of water to three of flour, by weight. But this proportion varies considerably, according to the age and quality of the flour. In general, the older and the better the flour is, the greater is the quantity of water required. If the dough, after being thus formed, be allowed to remain for some time, the sugar undergoes a fermen- tation, being decomposed into carbonic acid and alcohol. The gluten which exists in every part of this dough, prevents the car- bonic acid gas from escaping. It therefore heaves up the dough in every part, and more than doubles its bulk. The fermentation, however, does not stop when the sugar is decomposed. It con- tinues to act upon the alcohol, and gradually converts it into acetic and lactic acids. The consequence of this last action, which can- not be prevented on account of the slowness of the vinous fermenta- tion of the dough, is, that it acquires a sour taste and smell ; and if it be baked in the oven, though the loaf is full of eyes, and pos- sesses the characters of loaf bread, yet its acid taste and sm.ell ren- der it disagreeable to the palate, and unfit for the purposes of food. Dough that has been allowed to ferment in this way is called leaven. But if a small quantity of this leaven be mixed with new made dough, and the mixture laid aside for a few hours, fermentation commences, and goes on much more rapidly, so that the dough swells to at least twice its original bulk. If it be now put into the oven and baked, the fermentation is checked before any acid begins to be formed, and the bread is full of eyes, light, spongy, and sweet. The ancient Gauls and Spaniards, as we are informed by Pliny, contrived another method of bringing on a fermentation in dough. Instead of leaven, they added to the dough a quantity of the yeast or barm, which collects on the surface of fermendng beer.f This addition occasions fully as speedy a fermentation as leaven, and it is not nearly so apt to give the bread a sour flavour. About the end of the 17th century, the bakers of Paris began to substitute yeast for leaven. The practice was discovered and exclaimed against. The faculty of medicine, in 1688, declared it prejudicial to the health ; and many years elapsed before the bakers were able to convince the public that bread raised by means of yeast is better than that fermented by leaven. Barm is now employed in prefer- ence to leaven in every civilized country. In this country the yeast used by the bakers is made artificially, chiefly from potatoes. * See Jour, de Phannacie, xxii. 305. f Plinii Hist. Nat. lib. xviii. c. 7. Galliae ct Hispaiiibe triimento us i)oliirn resoluto quibus dixiiiuis geiicribus, spuma ita concrcta pro fermonU) utnntiir. ,:l m urn 1030 PANARY FERMENTATION. The process followed by our bakers is nearly as follows : — A certain quantity of salt is dissolved in water, the temperature of which varies, according to circumstances, from 70° to 100°. Yeast is mixed with this water, and then a portion of flour is added, but always less than is ultimately employed in forming the finished dough. The mixture is covered up and set apart in a warm place. Fermentation begins to be evident in about an hour. The sponge (so the imperfect dough is called) begins to swell up in consequence of the evolution of carbonic acid gas. This gas, being confined by the adhesive nature of the gluten, heaves up the sponge to twice its original bulk. Being no longer capable of containing this pent up gas, it bursts and subsides. This alternate rising and foiling of the sponge might be repeated a great many times. But unless the baker stops it after the second, or, at the utmost, the third dropping of the sponge, the bread invariably proves sour. He therefore, at this period, adds to the sponge the remaining quantity of flour, water, and salt, and incorporates these new mate- rials with tl)e sponge, by a long and laborious course of kneading. After this the dough is left to itself for a few hours, during which time it continues in a state of active fermentation, difflised tlirough every part of it. It is then subjected to a second, but much less laborious kneading, in order to distribute the imprisoned gas as equally as possible through the whole dough. It is now weighed out into the portions requisite to form the kinds of bread desired. These portions are shaped into loaves, and set aside for an hour or two in a warm situation. The fermentation still goes on, and gradually expands the mass to double its former bulk. They arc now put into the oven and baked into loaves. The mean heat of a baker's oven, as ascertained by M. Tillet, is 448°.* The bakers do not use a thermometer, but judge that it has arrived at the proper heat when flour, thrown on the floor of it, becomes black very soon without taking fire. This heat imme- diately stops the fermentation, but the gas already generated is swelled out by the heat, and gives the loaf its characteristic vesicu- lar structure. When bread is taken out of the oven it is lighter than when put in, from the evaporation of a portion of moisture during the baking. It would appear also, from the analysis of bread by M. Vogel, that a portion of the starch is converted into sugar. A few years be- fore the beginning of the French Revolution, the French bakers petitioned their goverment to investigate the loss of weight which bread sustains in the oven, alleging that the loss was very various, and that, on that account, they had been frequently taxed with dis- honesty without reason. M. Tillet and the other commissioners appointed to investigate the subject, in consequence of this petition, found that a loaf, which weighed, before it was put into the oven, 4'G25 lbs., was reduced, at an average, to 3*813 lbs. ; so that it * Encyc. Mctlioii. Alts et Metiers, i. 275. I'ANARY FERMENTATION. 1031 erature ) 100°. added, finished m place. J sponge sequence nfincd by twice its 3 pent up tig of the the baker ■opping of remaining ttew mate- kneading, ring -which ed tlirough much less ned gas as ow weighed jad desired, r an hour or pes on, and They arc lost 17*54 per cent, of its original weight. This somewhat exceeds -Jth of the original weight of the dough. They found, however, that this loss of weight was by no means uniform, even when the nature of the dough, the heat of the oven, the situation of the loaves, and every other appreciable circumstance was exactly the same. The diiference amounted in some cases to 7^ per cent. Other things being the same, the loss of weight sustained is pro- portional to the extent of surface of the loaf, and to the length of time that it remains in the oven. A loaf was weighed after beinjj baked, and was found to weigh exactly 4 lbs. Being replaced in the oven for ten minutes and then weighed again, it weighed ^th of a lb. less than before. Being put again into the oven for ten minutes, it sustained an additional loss of weight amounting to -j-'jjth of a lb.* Loaves are heaviest when just taken out of the oven. Unless they be kept in a damp place or wrapt round with a wet cloth, they gradually lose weight. Thus Tillet found that a loaf weighing at first 4 lbs. had lost, after being kept a week, about y'jth of its original weight. New baked bread possesses a peculiar taste and smell, which it loses by keeping, unless it be wrapt round with a wet towel. In that case much of the taste and smell ai'e preserved. Instead of yeast, bakers sometimes have recourse to sesqui- carbonate of ammonia, to render their bread porous. Somewhat more than a quarter of an ounce of this salt for every pound of flour employed is dissolved in the requisite quantity of water for convert- ing the flour into dough. After the wiiole dough is well kneaded, it is divided into loaves and baked in the oven. The heat expands the salt into gas, and gradually forces it out ^f the ("ough. But it remains long enough to fill the loaf full of eyes, and thus to render it sufliciently porous. While hot it still gives out the smell of am- monia, showing that the whole of the salt has not made its escape ; but the quantity remaining is too small to affect the taste of the loaf. It appears from the experiments of Dr FI. Colquhoun that when the flour is mixed with sesquicarbonate of soda, or carbonate of magnesia in fine powder, and made into a dough with water, hold- ing in solution the requisite quantity of tartaric acid, to saturate the soda or magnesia employed, the dough becomes loose, light, and spongy to a considerable degree. But the bread baked from it proved doughy and sad, and contained but few vesicles. t The mode of rendering gimjerbread vesicular, or of inducing in it the requisite panary fermentation, deserves to be described. The ingredients of gingerbread are Jlour, treacle, butter, pearl ashes, (or carbonate of potash) and alum. After the butter is melted and the potash and alum are dissolved in a little warm water, these three ingredients along with the treacle are poured among the flour which is to form the basis of the bread. The whole is then incorporated together into a stift' dough, the alum makes the bread lighter and * Encyc. Method. Arts ct Metiers, i. 270. Annuls of Philosophy, (Second Scries), xii. -207. ^.m i tm fU 1032 ACTKOJJS FBUMENTATION. crisped ; but its introduction may be dispensed with. The treacle acts slowly upon the potash, and gradually expels the carbonic acid which renders the dough vesicular. But the process is very slow. The dough must remain three or four days to eight or ten days before enough of gas has been extricated to render the dough fit for being baked. Indeed it has been found that it may stand even several weeks rather with advantage than with loss in this respect. Dr Colquhoun found that if carbonate of magnesia be substituted for pearl ashes in gingerbread, and the requisite quantity of tartaric acid to saturate the magnesia be kneaded into the dough, the ginger- bread is as well raised or as vesicular as when potash is used and it is fit for being baked within an hour ofter being formed.* The gingerbread made in this way is superior to that made by the baker's process, because it is free from the large portion of alkali which common gingerbread contains, and which renders it injurious when eaten in any quantity. The proportions which Dr Colquhoun found best are the following : — Flour ..... 1 pound Butter .... 3 ounces Sugar or treacle ... 2 ounces Carbonate of magnesia . . ^ ounce Tartaric acid . . . ^ ounce He found that if potashes be used, and the requisite quantity of sulphuric acid to saturate the alkali be added, the gingerb'^ead may be baked in the oven in a very short time after the dough has been kneaded. But the gingerbread formed in this way has a taste de- cidedly bitter. CHAPTER HI, O F T II E ACETOUS F E II IM E N T A T I () N. If wine or beer be kept in a temperature between 70° and 90°, while atmospheric air has access to it or some fermenting principle is present, it gradually becomes thick, its temperature augments, filaments are seen moving through it in every direction, and a kind of hissing noise may be distinguished. These intestine motions gradually disappear, the filaments attach themselves to tiie sides and bottom of the vessel, and the liquor becomes transparent. But it has now lost its former properties, and is converted into acetic acid. This intestine decomposition has been long distinguished by the name of acetous fermentation, because its product is acetic acid * Annals uf Pliilosopliy (Second .Series), xii, 27 o. ACETOfS FKHMENTATION. 1033 trcack lie acid ry slow, en days r\i fit for nd even respect, bstituted f tartaric e ginger- jed and it 1.* The [e by the 1 of alkali t injurious Colquhoun quantity of irb'-ead may igb has been ^8 a taste de- N. That this fermentation may take place, certain conditions must be attended to. The most important of these will appear from the following observations : — 1. Neither pure alcohol, nor alcohol diluted with water, is sus- ceptible of this change. The weaker the wine or the beer is on which the experiment is made, the more readily it is converted into vinegar : the stronger they are they resist the change with the greater obstinacy. But it results from the experiments of Beecher, that strong wines when they are made to undergo the acetous fer- mentation, yield a much better and stronger vinegar than weak wines. Hence it follows that alcohol, though of itself it refuses to undergo the change, yet when other bodies are present which readily ferment, is decomposed during the process, and contributes to the formation of the acetic acid.* 2. Wine, entirely deprived of glutinous matter, either by spon- taneous deposition or by clarification, does not undergo the acetous fermentation, unless some mucilaginous matter be mixed with it. Chaptal exposed old wine destitute of this matter, in open bottles, to the greatest summer heat of Montpelier for 40 days, and yet it did not become sour : but upon adding some vine leaves to the same wine, it became acid in a few days.f When the water in which gluten of wheat has been allowed to ferment is mixed with sugar, the liquid is converted into vinegar without fermentation, without eft'ervescence, and without the contact of air.:(: The nature of this curious change has not been explained. 3. Wine never becomes sour, provided it be completely deprived of all access to atmospheric air. In order to understand what takes place during the conversion of alcohol into acetic acid, we have only to attend to the constitution of these two bodies. Alcohol is C* H« O -f- H O while acetic acid is C* W 0=» + H O. The first thing that happens is the absorption of two atoms of oxygen from the atmosphere for every integrant part of alcohol present. These combine with two atoms of hydrogen and form water, leaving the alcohol in the state of C* H^ O -|- H O. Now this is aldehyde. The aldehyde has a strong affinity for oxygen. It absorbs two atoms of it from the atmosphere, and is converted into C* H^ O^ + H O, or acetic acid. From this it appears, that during the conversion of alcohol into acetic acid, every atom of alcohol absorbs 4 atoms of oxygen from the atmosphere. Hence unless the atmospherical air be constantly renewed, the process of acetification cannot go on. Even when the process is properly conducted about j^jih of the whole acetic acid formed is lost. But when the air is not sufliciently renovated to enable the aldehyde to absorb oxygen as fast as it is formed, a great deal of it is volatilized, and the consequent loss of i IP • These opinions have been confirmed by the experiments of the Commission appointed by the Paris Society of Pharmacy, to examine the Prize Essays given ill on the Theory of Acetification. See Jonr. de Pharmacie, xviii 364. f Ann. ul till of itd umlcr till" wi"i^?l>t of but wlicii of air, tlu' jportion of ccvunulatcd enon tukcs vert "^ into iior.ionti, A B Hic Bome- ;\ca b 'foro U cutcl'. f»r« of d.ynig oiK atioii of tcni- In tliis way il. The flic oil that had covered w\t\i loist oak hark a famiViar use it enough to oti, hydrogen, uirefaction is 'uses given oH' 1 of the very tlie cruciform me reason are on vegeta\>lcs le smell wiilcli c.) putrefy on \,vr. s'U powder, Ion given. A jfaction of t\ie . at the hegin- latter of whicli lure to nourish [the extractive lapotheme, ami which has been dtMcriht-d in a preceding ("haptcr of this work. 'I'he n/tothrfpf in an uiialy«is of tlie huinUM of wheat uiiiouuted t»> ahoiit *2(>i pci <"ent. It dissolved in potash ley. VViiaf tcmii' ' iindisiHolved. when ti'iMted with tiiiiriiiti(! acid, gave liiiu', pcruv .< of iron, and pli<'Sph»tc of liui- aiul then dixsolved in a great infUsuro in potash ley, '..M\ing about JO per cent, of clian'oal, or 4 nI i. k coinhnstilile matter ins((l,,i'1e in reuigeiits. Hoi-lhiy, junior, »uh|tTicd this apotlienio to analysis, and (ditdiucd the very same constitution as that of gallic acid, lie found the compound which i, forms with oxide of copper (for it posdosues tlio characters of an acid) com- posed of Apothemo . . . 8{)'5 or 42*^)1 Oxide of copper . . 10*5 ck- 5 4T(J1 This would make the atomic weight 42'C). But the atomic wcra;ht of gallic acid is 10'(>25, and it is eoniposod of ( "^ IF 0\ It i-^ ohvious from this, that the acid of huuius called y/mic acid by lir - connot, and geic acid by ''erzclius is composed of 28 atoms carbon . . . =z 'il 12 atoms hydrogen . . = 1*5 20 atoms oxygen . . . =20 42-5 and that its true atomic weight is 42*5. From the experiments of Saussnrc, we learn, hat when the in- soluble charry matter of humus is left exposed to tl." air, it gradually absorbs oxygen gas, which converts it into carboi ic acid, and by this diminution of carbon it becomes soluble in water, and assumes the characters of the acid of humus. m « riivs. XX. 1. APPENDIX. The two following acids were accidentally omitted. The first ought to have been inserted after page 62, as will be obvious from inspecting the table of fixed acids in page 52; the second should have been inserted after Section 6th, in page 63. OP CITRICIC ACID. Should have come in after Pj/rocitric, in page 62. This acid, which has been recently discovered by M. Baup, is formed when citric acid crystals are distilled.* To obtain it, the liquid which comes over when citric acid is distilled, is evaporated by a very gentle heat. The liquid being allowed to cool, the crystals of pyrocitric acid deposited are removed, and the process continued till small needle-form cryatals begin to make their appearance. From this moment, all the crystals deposited are set apart, in order to obtain from them the new acid, by dissolving them again in water and crystallizing a second time. The separation is easy on account of the great difference in the solubility of the two acids. Citricic acid thus obtained, is destitute of smell, but has a strongly acid taste;. The crystals are usually octahedrons, consisting of two four- sided pyramids, with a rhomboidal base. The primary form is a right rhombic prism. The adjacent faces of the two pyramids, constituting the octahedron, meet at angles of 136° 20'; while the pyramidal faces make with each other angles of 124° and 73° 15'. These crystals cleave easily into brilliant plates, parallel to the plane passing through the ob- tuse pyramidal faces of the octahedron. Citricic acid, at 50"*, Is soluble in 17 times its weight of water: at 68° it requires only 1 2 times its weight to dissolve it. Its solubility increases greatly with the temperature, and on that account a concentrated hot solution crystallizes on cooling. At 59° degrees it dissolves in 4 times its weight of alcohol, of the specific gravity 0*827. It is soluble also in ether. Though heated to 212°, or even to 248°, it loses no weight. At 322° it fuses into a colourless liquid, which crystallizes in plates on cooling. Just before it melts, it begins to exhale white irritating vapours, which have a peculiar smell. These vapours are condensed into white needle- form crystals. If we continue the heat, the whole acid is volatilized, without leaving any charry residue whatever, provided the heat has been cautiously applied. * Ann. de Chim. et de Phys. Ixi. 182. )■'! II ■^v mi 1040 APPENDIX. To detormine the atomic weight of this acid, M. Baup analyzed a quantity of anhydrous citricate of silver. 100 grains of this salt yielded 62*7.3 grains of silver, eqnivalent to ()7'39 grains of oxide of silver. Hence the salt is composed of Citricic acid . . 32'(;i or 7*01 Oxide of silver . . ()7'39 or 14'5 100-00 We see, from this analysis, that the atomic weight of the acid is 7, which is precisely the same with that of pyrocitric acid. He found it also isomeric ; for an ultimate analysis of the salt of silver with oxide of copper gave Carbon . . . 5.'J'572 Hydrogen . . 3*571 Oxygen . . . 42-857 100-00 Senaibly the same with the results obtained by Dumas, from the analysis of pyrocitric acid. The constituents, of course, must be 5 atoms carbon . . . =3-75 2 atoms hydrogen . . . = 0-25 3 atoms oxygen . . . =3 7-00 The crystals of this acid contain 1 atom of water ; or they are com- posed of 1 atom citricic acid ... 7 1 atom water . . . . 1-125 8-125* Citricic acid precipitates the acetate and subacetate of lead, and gives to the salts of peroxide of iron a red colour. The citrlcates occasion white precipitates also, when dropt into nitrate of lead, nitrate of silver, or nitrate of mercury. They throw down a red precipitate from the per- salts of iron. The citricates have a disposition to form supersalts, but this is not so strong as it is in the pyrocitrates. 1. Citricate oj' ammonia. This salt does not crystallize. When ex- posed to heat, it gradually loses ammonia, and is converted into bicitri- cate, which is capable of crystallizing. There are two bicitricates dif- fering from one another in the water of crystallization. The first is obtained, when the salt is crystallized, at the temperature of 68°, or a little below it, provided the solution be very concentrated, or that a crystal of the salt is put into the bottom of the vessel to hasten the crystallization. The crystals are transparent tables or prisms, not altered by exposure to the air; and, at the temperature of 53°^, they dis- solve in 1 J times their weight of water. The constituents of this salt are • Tlie name citricic acid, was given by M. Baup, because he thinks that the nomenchiture of isomeric bodies should bo improved. He proposes to distinjruisli them by the consonants, taken in the alphabetic order. Thus, the first discoveieii body isomeric with his, is the pyrocitric of Lassaignc. He proposes to call it citriliic | acid; his own he calls citricic; should a third be discovered, it would be called citrirfio; a fourth, citri/ic, and so on. , Baup analyzed a of this salt yielded of oxide of silver. 7-01 14-5 it of the acid is 7, acid. He found it ilver with oxide of s, from the analysis be .3-75 0-25 3 7-00 [•; or they are coiii- 7 1-125 3-125* ;e of lead, and gives 1 citricates occasion id, nitrate of silver, pitate from the per- ts, but this is not so rstallize. When ex- nverted into bicitri- two bicitricates dif- an. I, at the temperature ! very concentrated, ■ the vessel to hasten ables or prisms, not ire of 53° J, they (lis- tuents of this salt are luse he thinks that the proposes to distinguisl hus, the first discoveiel j reposes to call it citii/iic would be called citrirfic; 2 atoms citrieic acid 1 atom ammonia ■« atoms water APPENDIX. 1041 2 atoms citrieic acid \ atom ammonia ' * ^^ 4 atoms water * * " 2-125 4-5 Wh'en^^'''''"'^ «/iOO/«*A. This salf ^U ^^ f atoms citrieic acid i atom barytes ' " 14 2 atoms water ' * ' 9'5 2-25 5. Citricate of strontian Th^ . , 25-75 0- Citricate of lime Wl, .l i " me air, rated, the citriclte is denosifpV- ^'^"T' '^^'^t'O" of this salt i, . ] **oni citrieic acid . ^ atom lime . . ' ' ' 1 atom water ' * " ^'^ 1-J25 The bicitricate of lime fnrmc . ,.. ^ 1*625 2 atoms citrieic acid 1 atom lime . - • 14 3 atoms water ' " ^'^ 3-375 I JJ- ^^Mcate of maffnesia TJ, , 20-875 i I ¥ m w 1042 APPENDIX. 8. Citricaie of manganese forms reddish crystalline crusts, soluble in water. 9. Citricate of nickel, a very pale bluish-green powder, very little soluble in water. 10. Citricate of lead. It is formed by double decomposition, when solutions of acetate of lead and bicitricate of ammonia are mixed together. It is a white powder, soluble in an excess of either of the two salts em- ployed in its formation. Its constituents are 1 atom citricic acid . . 7 1 atom oxide of lead . . 14 1 atom water . . . 1*1 25 22-125 11. Citricate of copper. Very small acicular crystals, having a green- ish-blue colour, and very little soluble in water. 1 2. Citricate of silver. A white crystalline powder, composed of 1 atom citricic acid ... 7 1 atom oxide of silver . . 1 4*5 21-5 I'ARATAKTAniC ACID. Should have come in at page 63, ajler tartaric acid. When tartaric acid is exposed to a moderate temperature, it loses water, and is converted into a liquid, which concretes on cooling. This consti- tutes a new acid, composed of 3 atoms tartaric acid, and 2 atoms water. It forms with the bases a set of salts, differing in their constitution from the tartrates, being all compounds of 2 atoms of base with 3 atoms of tartaric acid. So that the water of the acid is replaced by a corres- ponding quantity of base. These salts gradually undergo spontaneous decomposition, being resolv- ed into free tartaric acid and tartrates. A still more remarkable alteration takes place Avhen tartaric acid is exposed to a higher temperacure. It loses an additional dose of water, and we obtain an acid insoluble in water, which is a compound of 3 atoms tartaric acid and 1 atom of water. With the bases it forms neutral salts, containing 3 atoms tartaric acid and 1 atom of base. We see here the striking analogy between tartaric and phosphoric acid.* svBAnrLLiNA (page 243). M. SiMOX, of Berlin, assures us that the sabadilliua of Couerbe is nothiiif; else than a compound of resinate of soda and resinate of veratrina. It we dissolve it in water acidulated with sulphuric acid, and precipitate bv an excess of ammonia,- we obtain pure veratrina.f DLMASIN {page 3G2), This is a name given by Mr Kane to a new substance which he obtained | in minute quantity, together with acetone, when acetate of lime was dis- tilled at a high temperature. It is a liquid, which boils at 248°, and ha- Frcmy, Atiii. dcr Plinrm, xiv. 197. f See Poggendorf's Annalen, xliii, 40.ll APPENniX. 1043 ts, soluble ill ir, very little losition, wlien lixed together. , two salts em- having a green- Bomposed of 1-5 1-5 ric acid. ure, it loses water. ling. Thisconsti- and 2 atoms wattv. their constitution base with 3 atoms ^.laccd by a corres- isition, being resolv- len tartaric acid is ional dose of water, omvoundofSatoms * forms neutral salts, Uic and iihosphoric Couerbe is nothiud [ate of veratriiia. , and precipitate \)vl Ice which he obtained Ute of lime >vas d>H ],oilsat248»,audlu^' Lrfs Annalen. xliii. m\ a resinoid character. According to the analysis of Mr Kane, which has been confirmed by Dumas, its constituents are Carbon . . 78-82 or 10 atoms = 7*5 Hydrogen . 10'4() or 8 atoms = 1 Oxygon . . 10-72 or 1 atom = 1 100-00 9-5 It is therefore isomeric with camphor, though nothing can be more dif- ferent than the properties of the two bodies. The specific gravity of its vapour is 5-204. Now 10 volumes carbon weigh . 4-16G6 8 volumes hydrogen . , 0-5555 i- volume oxygen . . . 0-5555 5-2777 We see from this that it is composed of 10 volumes carbon, 8 volumes hydi-ogen, and half a volume oxygen, condensed into 1 volume. This is the case also with the vapour of camphor, with which dumasiu agrees in composition, though its properties are very different. I'KCTic Acin {pngn 146). M. Regnault has subjected pectic acid to an analysis, and found it com- posed of Carbon 42*71 or 11 atoms =: 8-25 or per cent. 43-14 Hydrogen 4*73 or 7 atoms = 0-87 > — — 4-57 Oxygen 52-56 or 10 atoms = 10-00 ~ — 52-29 100-00 19-125 100-00 M. Regnault endeavoured to determine the atomic weight of pectic acid, by mixing in various ways pectate of ammonia and nitrate of silver. But the salts formed were obviously mixtures. Tliey consisted of 14-5 oxide of silver combined with 23-66; 24-61 and 21-40 of pectic acid. While pectate of lead was composed of 1 4 oxide -f- 1 4-6 pectic acid.* ACKTONE {page 362). The constituents of this substance, from the analysis of Liebig and Dumas, have been stated (page 364), to be C^ H^ O. Mr Kane, of Dublin, has made an interesting set of exjieriments on the compounds derived from this substance, which he considers as analogous to alcohol, and which he has called mesitic alcu/toL He re])resents the constituents by the formula C" H*' O'^, or double the preceding, so that its atomic weight is 7'25. When acetone is mixed with sulphuric acid and distilled, a colourless liquid passes over, having an alliaceous smell, and boiling at 276°. It is composed of 6 atoms carbon .... 4-5 4 atoms hydrogen . . . 0-5 Mr Kane has given the name of mesytelen to this liquid. When perchloride of phosphorus is made to act on acetone, phuspho- * See Jour, de Phaimacic, xxiv. 201. ii ■ ' I i'^^ 1044 APPENDIX. mesitylic acid is formed, together with a fluid heavier than water, and composed of C^ H'' Chi. Mr Kane considers this liquid as the chloride of a radical of mesitylen, to which he gives the name of mesityle. He has obtained C H* + O, or oxide of mesityl C« W + Chi, or chloride of mesityl Q6 JJ5 ^ JqJ^ qj, iodide of mesityl. Oxide of mesityl unites with sulphuric acid in two proportions, forming the sulphate and bisulphate of mesityl. He calls the salts of the former acid, sul/)homesitiflateSy and those of the latter, persidphomesitylates. The base of these salts is just capable of neutralizing the sulphuric acid which they contain. Thus, sidphomesitylate of lime is S O^ + C" H** O + Cal O + H O. When, in the process of making iodide of mesityl, an excess of phos- phorus is used, there is obtained in the retort a white matter in silky crystals, which dissolves in water, is very acid, and forms well character- ized salts. Mr Kane calls this acid hypophosjihomesitylous acid, and states its composition to be Ph'^ O -f- C** H"' O. In decomposing acetone by perchloride of phosphorus, an acid is obtained, composed of Ph OH -f 2 (C H^ O). When dry chlorine gas is passed into pure acetone, muriatic acid is given off, and white prismatic crystals formed composed of C* H^ Chi. A yellow substance obtained by the action of iodine, or nascent mesitylen, was considered by him as composed of C* H^ lod. when mesitylene is treated with nitric acid, copious red fumes are given off", and a heavy thick fluid obtained, composed of C" H^ C*. This fluid absorbs ammonia and forms a compound soluble in water, and giving insoluble precipitates with most metallic solutions. When acetone is heated with concentrated nitric acid, the action is violent and explosion takes place. The addition of water prevents this ; but the resulting product cannot be analyzed. To connect the above results Mr Kane assumes as a radical the body C H^, which he calls pteUyl. Q(, PJ3 ^ Yi, Hydret of pteleyl, or mesitylene C« H3 -f Chi., Chloride of pteleyl C W -t- lod., Iodide of pteleyl C H'^ O -f H O, Hydrated oxide of pteleyl, the aldehyde of the mesitJc series C^ H^ O + Az O^, Hypouitrate of ptelyel. The compound heavy liquid, produced by the action of chlorine on mesitic alcohol, was composed of C*' H^ O^ Clil'^. By the action of bases it yields a metallic chloride and a salt of a new acid, called by Mr Kane Pteleic acid. He conjectures it to be C" H^ O*. By the action of permanganate of potash on acetone, a salt is obtained | containing an acid, to which Mr Kane has given the name of perptvlek. Its salts readily decompose themselves into carbonates, and a salt of anotluT acid, which Mr Kane has called acctonic. These acids have not yet been sufiiciently investigated. The paper containing these interesting investigations was read to the Irish Academy on March 16, and April 10, 1837. ORCEIN (page 404). This substance has been analyzed by Dumas, who found it composed of Al'PENDIX. 1045 an water, and 9 the chloride mesitijle- He .rtions, forming ,9 of the former esitylates. T^e axivic acid which 3 + C*^ H^ O + 1 excess of phos- 3 matter in silky „s well character- ifylous acid, and ^orus, an acid is e muriatic acid is 5ofC«H«Chl. iodine, or nascent H3 lod. ious red futnes are ,f C*^ H* O • ^^'^ in water, and givmg p acid, the action is [water prevents this; , a radical the hody the aldehyde of the Lion of chlorine on Ivtiie action of hases 1: called hy Mr Kuue Inc, a salt is ohtained le name of perptrlm L,andasaltofanot\u. Vds have not yet heeu Lions was read to tbe I ^ound it composed of 16 atoms carbon 8 atoms hydrogen 1 atom azote 6 atoms oxygen = 1-75 = 6 20-75 It combines with 2 atoms of oxide of silver, and forms a diorceate of silver. According to Dnmns, orcin is composed of 18 atoms carbon =: 13*5 or per 10 atoms hydrogen =1*25 — 5 atoms oxygen =: 5*0 — cent, 68-36 6-32 25-32 19-75 100-00 This is one atom of hydrogen less than by the analysis of Robiquet. GAi.ACTiN Cj)age 448). Since writing the accomit of galactin I have subjected it to aa ultimate analysis, and obtained Carbon 71-90 or 6 atoms = 4-5 or per cent. 72 Hydrogen 11-87 or 6 atoms = 0-75 — — 12 Oxygen 16-23 or 1 atom =1 — — 16 6-28 100 It is therefore isomeric with Brazil wax, as may be seen by comparing Oppermann's analysis of Brazil wax, given in page 447, with the above analysis. From Oppermann's short description of Brazil wax, I think it likely that it is the same substance as galactin. It is white, he says, has a specific gravity of 0-97, melts at 102°, and becomes solid at 97°. He says, indeed, that it combines with alkalies, and forms a soap which is soluble in water. Should this be confirmed by subsequent experiments it will constitute an important difference between the two. But Brandes says '^xpressly that he could not combine Brazil wax with alkalies. bees' wax (page 444). It is stated that hees^ wax was, by John, separated into two distinct sub- stances, cerin and mi^ricin. But M. Hess has published a set of experi- ments to prove that bees' wax, when pure, is always of the same consti- tution and characters ; but that, by oxidation, it is converted into an acid, which he calls cerainsaune, and to which we may give the name of eerie acid. The difference between cerin and myricin he considers as owing to the presence of more or less of this acid in the wax. He took a quantity of yellow wax, and by means of ether deprived it of the colouring matter. The remaining white wax possessed the characters of the myricin of John. He found the constituents of wax to be Carbon 79'77 giving 20 atoms = 15 or per cent. 81-0 Hydrogen 12-95 — 20 atoms =2-5 — — 13-5 Oxygen 7-33 — 1 atom =1-0 — — 5-4 100-00 18-5 100-0 In eerie acid the carbon and hydrogen have the same ratio to each other as in wax ; but the oxvgen is increased. He considers it as a compound of r|i 104G APPENDIX. 20 atoms carbon 20 atoms hydrogen 3 atoms oxygen rr 15 or per cent. 73" 17 = 2-5 — — 12-19 = 3 _ _ 14-64 20-5 100-00 It is not unlikely that M. Hcss's explanation of the supposed difterenco between corin and myricin is correct, but his formulas (lo not coiTcspond so well with the result of his analysis as those of Ettling.* voLATiLK OILS (page 452). A PAPER, detailing the analysis of several volatile oils, by Mr Kane of Dublin, was read at a meeting of the Royal Irish Academy, June 12, 1837. I shall here state the results. 1. Oil of mentha pttlegiiini, or pennu royal. It boils, like oil of tur- pentine, at 314°, and is composed of C H**. 2. Oil of ini'iitha sat'wn. It boils at 320°, and is composed of C^" IP** O, or of 3HC"' H«) + O. 3. Oil of originnni vulgare, or marjoratn. It boils at 324°, and is composed of C*" H*" O, or 5 (C'» H**) + O. 4. Oil of lavender. It boils at 365°, and is composed of C'^ H'" O. 5. Oil of rosemary. Its specific gravity is 0-85, and it boils at 332°. It is composed of C'' H"** O^ or 4^ (C'» H**) + H^ O^. 6. Oil of peppermint. Pure English oil of peppermint has a specific gravity of 0-899, and boils at 365°, and is composed of C^'' H''^ O^, or 2^ (C'" H") + 2 (H O). This differs from the analysis of Blanchet and Sell, given in jiage 474 of this volume. But Mr Kane found that foreign oil of peppermint was always mixetl with oil of turpentine. OIL OF CLOVES (page 465). Di'MAS has made a new analysis of oil of cloves, to which he has given the name of eugenic acid, and considers it as composed of 20 atoms carbon . . . =15 12 atoms hy(U-ogen . . =: 1-5 5 atoms oxygen . . . =5 21-5 But he determined the specific gravity of the vapour of this acid oil, and found it 6-4. It is obvious from this that the true atomic weight of tho acid cannot be far from 24. For 23-75 X 0-2777 = 6-6. Hence the con- stitution of the acid is probably 23 atoms carbon =z 17-25 or per cent. 71*87 14 atoms hych-ogen = 1-75 — — 7-29 5 atoms oxygen =5 — — 28-84 24 100-00 which agrees well with the result obtained by M. Ettling, and given in jtage 468 of this volume. EMULSIN (page 682). M. Simon, of Berlin, prepared emnlsin from bitter almonds, sweet almonfls, l)oppy seeds, hemp seeds, and black and white mustard, by the followinfj process : — * Sre PoKgeiuliirl's Ainiak'ii, xliii. 38:2. APIMCNDIX. 1047 17 19 G4 •00 loaed lUfferenco not correspond One part of the seeds was made into an emulsion with eight parts of water. The emulsion heinjr passed through a clotli, was mixetl with a suilicient quantity of alcohol to coagulate tlio whole. Tiie coagidum was separated by the filter, dried, reduced to powder, digested with ether till that liquid ceased to dissolve any fat oil. It wu.. then washed with alcohol, again dried and pulverized. The emulsin from all these seeds, when mixed with amygdalin, produced the smell of hitter almonds. That from bitter almonds acted most powerfully, that from sweet almonds next, that from hemp seed was weaker, and that from mustard weakest of all.* by Mr Kane of demy, June 12, ,, like oil of tur- posed of C"* H s at 324°, and is 1 of C^^ H'° O. d it boils at 332°. nint has a specific 3f C'^5 H'^2 OS or is of Blanchet and found that foreign tine. lich he has given of 5 1-5 5 ^f this acid oil, and omic weight of the 6. Hence the con- TABLES, SHOWING THK SPECIFIC GRAVITY OF TIIK VAVOUH OF VARIOUS VOLATILE BODIES, THAT OF AIR HEINO RECKONED UNITY. There is an intimate connexion between tlie specific gravity of the vapours of bodies and their atomic weight, as is manifest from the doc- trine of volumes, so happily established by M. Gay-Lussac. This renders the knowledge of the specific gravity of vapours of importance. It often furnishes data for determining the atomic Meight of bodies, which, not being capable of uniting with other substances in definite proportions, could not be ascertained by any other known method. I shall therefore, in the following tables, exhibit tlie specific gravity of the vapours hitherto determined. For these determinations we are chiefly indebted to the ingenious labours of M. Mitscherlich and M. Dumas. The specific gravity of a vapour is always equal to its atomic weight, multiplied by a certain number, which is always a multiple or submultiple of the specific gravity of oxygen gas. The reason of this is, that oxygen is the substance whose atomic weight is represented by unity. The specific gravity of oxygen gas is I'llli, and the only submultiples or multiples of that specific gravity, which, multiplied into the atomic weight of a vapour, gives its specific gravity, are 0-2777 or ^thof MUi 0-5553 or i of 1-1111 1-1111 2-2222 or twice 1-1111 3-3333 or thrice 1-1111 71-87 7-29 '28-84 [00-00 [tling, and given m * See PoggenUovfs Annalen, xliii. 404. iP Lis, sweet almorifU, Id, by the followmj- 1048 AVPKNUIX. t- *- (N •r 'fe. •* (N ■if) •a'l.h". §^ ^ 17 U9 t^ t" >0 »« .ifl .» to « -^ f •>- ."O W — ?0 h- ->! x V5 >C i;- M (N I,- T" «p Oi >0 ^ «o o «o 'O — ' (M — 1 t;. M V5 >C i;- M (N I,- T" «p Oi >0 ^p ?5 9 (?l O) I- -< t- M iM -N CI 1« Ol «0 « h- 05 Oi to W5 «0 (p do V9 '" .« ''^ t^ »c to .« — 'i' ^ ^ "5 -^ ^ — rt I'- ^ Oi V9 »0 oc V5 V5 ++ II II 12 s«i «^ J2 I! s^i £! — Jl « « S- S, — 00 CO t: >o 00 ^ o C/J « 1-. il d«3£. OOM la OMO-' K S t w 9 P4 is .a tJ -5 bp 's^ a a 0) to "Tj _a > « « «^^ 0) »4 V V -a i-^ U 'f -S -a ?«, -s -5 -S o «2 «2 - 13 « .2 -3 3 a O -3 ^-3 p o « «*j O aj 3 § P, I i ^,-B 5 S a c3S:g^^cSiS;SSoeS:sK^g^cSfrss2& APPBNUIX. 1049 , 00 t7 r* ^ 9 ^ ^ CO i?< «*' *^ ^ ^ « » ^ O C ;j J, ^ « , , ' • • • u HI ^ . M « • t • ■ % u I fe-^-a o 1 (^ V V O n3 1 s-s u-e 9 "a 5 g e 1 V u ^ w &-0 a 1 «-s a s ^^l-s Aceti Benz Pyro Chlo j 1 — 85 eo •« «o '^ n (M — f^aOQOf^CTJ«l(N C -^OOO'OI-^QOCM ^^ g u £ ■A '{■ IC 1 — M ?0 « M '^ b- (MMaOCtiWJ'OCO — p ,^^^M(N5 Ih-^ " I I a ^ ^ O S t^ ft O " 5> « O rt tC '-f ifl W5 db '^ a^ *i ».'5 r< W5 M O i^ O Q « 1^ ^ O) "T" 'N ^ 9 db t«» d^ ifi ^b CO V 2 J3 a 3 V5 b- »0 >(5 do II II ih's J3 fci "^ o pJ3 tj "g -^ "O "O ""O ^^ 3 8. 9) >^ a 2 I s I» a o I 3 U » hS IS U m ^ !/3 :0 ior)0 Ai>i'i!;Nnix. I ; ^" I- X — lO ^1 p ^ >c "5 tp -r f I- f ?l P Qt. I- -< (M r- 1^ (N f W5 «0 p -f — ^? -J ■M lO kO #1 l" f W I- >i? »/5 OO — o I- I- iM -r « 99 - - -- ^ij ifl I- Ti I' fO 'X> ^ C'l f en >c ^xt Ix * ^Svii:^ r- ^« o r. t 1 < V'? II 11^2 II JS ^ ^ 4- O y U U c/i * 1 II •' ''^ ^ « II "? >« "^^ •' US ji--,n+++++ii]iiSM„^«ii-£i o-«oocooooon ll??o°JloJ' || || X II 12 II i o"' 11 o 33 RK = ^ O o « & u o ■* ^«f«f'*>»'*'^cM5'l«'l(Mt»-<_cO — '-"S-'Ote -^i;i'' "* tJc^OUUUUUOUUUOUUOCJOUUOUO Z!,u;j ■■go Ti ' 1 ^ ® o ^ 3 3 -O U a> 0) h o; •J= 3. *- 2 =5 -= S3 — ; -t-i S3 J *J -« ^, « _ •♦J « '5 .= .5 fl - r2 u S ~ _ O 4i O O 'P 4) O « 01 -5 !S S 5 a -< v: •< W O C a "5 g^s 2-a "5 -2 jc ■a §^ o a u J03 C^Rs+Chl C*H^O'' C^H^O* C'"H7 C10H8 Cioip C'"H8 C10H8 C10H8 C«H=*03 C'H^O* C^O^'Chl C'"H«0» C^H^O+C^O^ C^H^O+C'H^QS C*H50+C^H03 C'0H«O Ci«H«0 C'^H^O C"H»0 9-625 Butyric acid . C«K'0» 9-625 Oil of cajeput cm^o 9-625 Suberic acid . cm^o^ 9-75 Camphor from oil of la- vender CiOHiOQ 9-75 Allantoin C^AzHH'O' 9-875 Pyruvic acid . CH^O^^ 9-875 Cahincic acid C^lH^O'^l 9-875 Creosote C«H3JO 9-9375 Acetal .... CH^O' 10-125 Caffeic acid C^H^Oe 10-25 Glycerin C«H705 10-375 Cyanamide C^H^Az* 10-5 Pasto resin C10H8O2 10-5 Chloroeyanate of methylene C^H-^O+C^AzChl 10-625 Gallic acid C^H^QS 10-625 Persian naphtha C12H12 10-625 Parillina C9H«03 10-75 Stiracin .... C^H^O^ 10-875 Succinic ether C^H^O+C^H^O^ 10-875 Urethan C«H7AzO* 10-875 Acetic ether . C^H'^O+C^IPOS 11 Quassite C10H6O3 11-25 Oil of lavender C12H10O 11-25 Benzone C'^HSQ 11-375 Camphoric acid C'"IFO' 11-375 Phocenic acid c'"m*o» 11-4375 Melon .... C«Az* 11-5 Nitrosulphnric acid 2(AzO^)+SO^ C^«H«03 11-5 Sebacic acid . . . 11-5 Bicoloric acid C«H^i08 11-5625 Valerianic acid C'H^O^ 11-625 Hydromelonic acid . C«Az^H 11-625 Naphthalic acid (jiojjao* 11-75 Bromide of deutohydrogen C^H^+Br 11-75 Paranaphthalin U(C"'H^) 11-75 Pyrotartaric ether . C" C12H^04 13-5 2(PhO'-**)+C^H^O C^^H^O* 13-625 13-625 C^H-'Br 13-625 C^H^O+C^O'Chl 13-625 C^H^O-l-C^O^Chl 13-625 C'lI'^O 13-75 C'WO* 13-75 C16H1G 14 2(S03)4.C2H30+HO C\4H130^ 14 14-125 C«H5AzO« 14-375 C^H«0+C«H«03 14-375 C'^HHSO^ 14-625 S^O-'+C^H'O+IIO 14-625 C«H*5Az'* 14-6875 CiCH^o 14-75 C2H30+2(C2AzO)+3(HO) 14-75 2(C203)+C^H50+HO 14-75 C'^H30+C«H<07 14-875 C12H70S 14-875 C«H«AzO» 15 i(AzO')+Ci"H''0* 15 C"H^O'^+AzH^ 15-125 C^H+Chl'' 15-125 C^^H'^o 15-125 2(S''^C)+C^H50+HO C^«H'*AzO 15-25 15-375 C/FPAzO'+AzH^ 15-375 C'^H^AzO^ 15-375 2(SO=»)+C^H^O+HO 15-75 C''II«Az« 15-75 CRSAz^O^ 15-878 1056 APPENDIX. Nf:,^f Composition, Atomio weight. Solid chloride of naphthalin C>"H3Chl2 15-878 Amelide . . . C«H**A!!!20« 16-75 Cerain .... C18H180 16-75 Myraciii C'SH'SQ 16-75 Catechuic acid C'5H»0« 16-875 Benzoate of methylene . Cm^O+C'^H^O' 17 Petrolene C20H»6 17 Camphene C20H1G 17 Cinnamonic acid C18H703 17-375 Azulmic acid CSR^Az^O* 17-5 Pyromucic ether C^HSO+COH^O" 17-5 Iodide of deutohydrogen C^HHlod 17-5 Chloride of benzoyl C'4H502 + Chl 17-625 Spiroilic acid C'2H50*+0* 17-625 Cholesteric acid C'3H'"AzlO« 17-875 Resinein C^OH'SQ 17-875 Anchusic acid Ci7H'0O< 18 Capric acid . C<8H'403 18-25 Ch oral C*H02+Chl3 18-628 Amidin .... CiOfiiOQio 18-75 Benzoic ether C^H'O+C'^H'O' 18-75 Iodide of metliylene C^H^O+HIod 18-75 Menespermina C'sH'^AzO^ 18-75 Qinanthic ether C*H50fC'^H30'» 18-75 Roccellic acid C'7H'604 18-75 Hyposulphonapthalic acid (S03)+C"H*» 18-8123 Lichenin C'0H"O'0 18-875 Caryophillin . C20H'GO2 19 Capaiva resin 2(C'"H80)? 19? Pectic acid cmo'" 19-125 Iodide of aldchyden C^HHlod 19-125 Iodide of ethyl C^HHIod 19-375 Sulphoglyceric S20HC«H705 19-375 Tartromethylic acid 2(Cm205)+C2H30 19-375 Metameconic acid . C'^H^O'o 19-5 Succinono C'H'OQ^ 19-75 Cinchoniua C2"H'2AzO'» 19-75 Orcin C'«H'"0» 19-75 Bassorin C'0H"O" 19-875 Bromide of cyanogen lKC''Az)+Br'* 19-875 Atomio weight. Al'PENDIX. 1057 Compodtlon. Atomio weight. Asplialtene Q20JJ.6O3 20 Amylin C'^H'^O'" 20-25 Horde in C'^H'OQ'" 20-28 Quiuina C^«H'^AzO^ 20-25 Common sup^ar (jiajIiOQio 20-28 Suf^ar of milk C'^H'^O'" 20-25 Cliloronaphthalase . C^oH^Chl 20-375 Chlorophenesic acid C'^FPO^Chl^ 20-375 Uacemometliylic acid 2(C*H20')+C2H'0+HO 20-5 Kesineon C"H'«0? 20-5 Phloridzin C')+C»HS0+H0 22-25 Lignin .... (j.SHioQio 22-5 Sugar of grapes C12fJ,20'2 22-5 Nitrate of melamin C«H«Az<5+AzOS 22-5 Oil of mustard S^iC'OH'OAzO'^i 22-5 Mannite C'^H'^O 22-75 Atropina C^^H'^AzO^ 23-125 Bromide of benzoin Cni^O^+Br 23-125 Oil of roses . ^23^2303 23-125 Sabadillina C^OH'^AzO^ 23-375 Benzosulphuric acid S20''+C'«H«02? 23-5? Bromic ether C'H^+Br2 23-5 Crystals from oil of tur- \ jientine . . J C20JI20OG 23-5 Oil of peppermint . 2*(C'<'H8)+2(HO) 23-5 Bromide of spiroil . C'^H^O^+Br 23-625 Hydrosulphuret of cyanogen 3(C2Az)+6(HS)+HO 23-625 Nitrate of ammelin C^H^AzSQ^+AzO'' 23-75 Arseniovinic acid . 2(ArsO20+2(C^H-^O)? 23-75? Oil of cloves, or eugenic acid C"H'^0' 24 Volatile oil of mustard . S^SC'f'H'OAzH)'^'' 24-25 Chloronaphthaleso . C^OH^ChP 24-75 Ciilorophenisic acid C'^H^O^Chl'' 24-875 Sulphonaphthalic acid S203+C2"H7 24-875 Pollenin of lycopodium . C'7H'7]O'0 24-9375 Ricinic acid . C^^H^^O* 3y 25 I I' 1 1058 APPENDIX. Comiwsitioii. Atomic weight. Thebaina C'SH'^AzO" 25-25 Bromonaphthalese • • C^m+Br 25-875 Benzosulphate of methylene C2H304-(S'^0^+C'«H^02) 26-378 Tannic acid . ■ • C'»H«0'2 26-5 Delphina • • C27H'«Az0^i 26-75 Nitronaphthalese • C2«H«+Az2 08 27-25 Benziinide • • C=^«H"AzO« 28-125 Amide of oil of mustard S2jC'eH"'Az202' + Az-'H* 28-25 Camphovinic acid , , 2(C'»H703)+cm'0+HO 28-5 Iodide of bcnzoil • • C'4H502+Iod 28-875 Iodide of spiroil • • C'2H50Hlod 29-375 Oil of mcntha sativa 3KC'°H8) C3^iH320 29-75 Ambrein 30-125 Strychnina C3"H"'AzO< 30-25 Margarone C34H320 30-5 Carbazotic acid C'«Az-'0"^ 31-5 Bromoform . C^H+Br^ 31-625 Wax of ceroxylon andicola C35H2902 31-875 Muriate of cetene 2rC'6H'G)+HCi.l 32-625 Staphisin C32H24AzO^ 32-75 Codeina C^rn'OAzOs 33-125 Coal naphtha C39H240 33-25 Elaidic acid . C35H3303 33-375 Bees' wax C37H3902 34-625 Brucina C^^HisAzO^ 35 Iodic ether C^H^Iod^ 35 Bromal C8Az0'2 40 Oil of marjoram 5(C"'H8)+0 43-5 Narcotina C^'-H^'AzO'^ 46-25 Iodoform C^H+Iod^ 48-875 Insoluble chloral C'^H^OHChF 52-5 Gentisic acid 54-73? Amygdalin C^OR^^AzO^^ 57 Amygdalic acid C.10jl2fiQ2.1 57-25 Oleoa CGSHGOO 59-5 Stearone CG8HG70 60-375 Sulphocetic acid S205+C'''nF2^2(HO) 63-25 APPENDIX, 1059 Atomic weight. Stearic acid . Metaniar{>;arie acid Oleic acid Santonic acid Esculic acid . Metoleic acid . Margaric acid Hydroleic acid Hydromargaric acid Olein Aui-ade . Stearin . Speriii. .eti Ciimposition. C7on"o5 Cr,ojj:iOQi2 C70H70O'J (;70H)+2(C7"H'"'0»)+ ) ) 3(C'«H'«)+-'HH0) 'I Atomic weight. 65'-875 GG-875 67-25 67-5 68-75 69-5 7028 70-625 71-375 77-625 86-875 144-375 308-375 THE PRECEDIXr. ATOMIC WEIOHTS AKllVNGED ALPIIABETICALL'K. Composition. Atomic weight. A Acetal .... C«H»0» 10-125 Acetate of methylene C^H'O+C^lPO^ 9-25 Acetic acid C^H^O^ 6-375 Acetic ether . C^IPO+C^H^O' 11 Acetone C^IPO 3-625 Alcohol C4HSo2+Br 23-125 Bromide of cyanogen U(C^Az)+Br'i C^lP+Br 19-875 Bromide of deutohydrogeu 11-75 Bromide of ethyl . C^H'Br 13-625 Bromide of spiroil . C'^Il-'0*Br 23-625 Bromoform C^H+Br^ 31-625 Broiiionaphthalase . C2''H7+Br 25-875 Brucina C32H'«Az07 35 Butyric acid . C»H503 9-625 C Caffeic acid . C^H^O« 10-25 CafFein .... C^H^lAzO 6-0625 Cahincic acid C7.H«03i 9-875 Cajeput, oil of C'H'^O 9-628 Camphene C20JJ16 17 Camphor C'^HSQ 9-8 Camphor from oil of anise C'"Heo 9-25 Camphor from oil of eubebs C'«H'*0 14-75 Camphor from oil of la- | vender . . | C'-H'^O? 9-75? APPENDIX. 1061 Atomic weight. 21-25 23-75 7-5? 15-375 14-375 20 23-125 86-875 17*5 19-875 15-128 20-125 4-878 17 14-125 18-75 13-25 11-375 23-5 13-125 40 11-5625 26-375 12-875 6-25 35-125 23-5 13-375 23-125 19-875 11-75 13-625 23-625 31-625 25-875 35 9-625 10-25 6-0625 9-875 9-628 17 9-8 9-25 14-75 9-75? Camphor I'rom oil of paisU'y Cuinphoric neid Caniphovinie acid . Caoutclu'tio Caoutchouc Capric acid Caproic acid . Carbazotic acid Carbonic ether Caryophillin . Catechuic acid Cerain . Cerasin . Cerin Cetene . China nova bitter . Chloral . Chloric ether Chloride of aldehyden Chloride of benziu . Chloride of benzoyl Chloride of cyanogen Chloride of deutohydrog Chloride of ethyl Chloride of methylene Chloride of spiroil . Chlorocarbonic ether Chlorocyanate of methylene Chlorocyanic ether Chloroform Chloronaphthalase . Chloronaphthalese . Chlorophenes'c acid Chlorophenisic acid Chloroxalic acid Chloroxalic ether . Cholesteric acid Cinclionina Cinnamon, oil of Cinnamonic acid Citrene . Citric acid Citric ether . Citricic acid • Cloves, oil of . Codeina Columbin Conicina Copaiva acid . Copaiva, volatilo c)il from Copaiva resin t'umposition. Atomic weight. C"WO^ 6-875 C'lro' 11-375 2(C'H70')+C«H50+IIO 28-5 C'li' 0-875« C^H* 3-5 c"*ir^o' 18-28 cm'^o^* 13-25 C'^AzH)"' 31-5 C«Az02J 26-75 Deutohydrogen C^H^ 1-75 Duinasin C^OFPO 9-5 E Eblanin .... (J21fIUQ4 20-875 Elaidic acid . C35II3303 33-375 Elaidic ether . C«IPO+C''»II"0' 38 Elain of Fremy CaR" 7-875 Elemi rcsiii C>0H«Oi 9 Ellagic acid . cm^o' 9-5 Emctiua C3'>Il"Az()'' 40-125 Emulsin C2«H"Az'0» 36-875 Eiiaiithic etlu'i- C«IPO-fC:"H''0^ 18-75 Equisetic acid C*H03 6-125 Esculic acid . Cf.2lI4002» 68-75 Ethal . C'TI'^O 15-125 Ether . C'H'O 4-625 Ethionic acid Sl^O'+C'H'O+HO 14-625 Eugenic acid . (yj3iino5 24 Eupioii . C'JiH'o 8-375 F Fennel, oil of . C'»H«0 9-25 Fluoride of methylene C-^H^O+IIFl 5-25? Formate of methylene C^H^O+C^HO^* 7-5 Formic acid . C^HO^ 4-625 Formic ether . C«H»0+C^H03 9-25 Fuinaric acid . CH^O' 7 G Galactin C«H«0' 6-25 Gallic acid cnvo'' 10-625 AI'l'KNDIX. 10G3 Alumic 7-75 10-5 H'7.'i i«)-;n5 4-25 it;-i28 G-875 3-28 8-0(J25 8-8G2:) 15 (lontisic acid . (ilyci'rin H llovein . Ilordoln Hij){)iiric acid Hydrocai'bosulpliiiric acic Ilydroeyaiiie acid . Ilydi'oK'ic acid Ilydromarjifaric acid Hydronu'lonic acid IIydros[)ir()ilic acid Ilydrosulphurct of cyaT>o gen . . . I lydrosulphocyanic acid Hvpoiiitroinecouic acid Hyposulphonaphthulic uc Japonic ncid . Idrialin . . Indigo . Indigogcn Indigotic acid Insoluble chloral Iodic ether Iodide of aldehydeii Iodide of benzoyl Iodide of deutohydrogen Iodide of ethyl lodid'i of methylene Iodide of spiroil Iodoform Iris florentina, oil of CuiniHMitloii. id K Kinic acid Lactic acid Lavender, oil of Lavender, camphor from oil of . Lemons, oil of Lichenin Lignin . . . . } c^iro* C'll' c;"*irA/,()' S'^C+SII CU/,+II C^"IF'()"* C'''A/.^+H C'^II'O' 6-25 10-620 U Maleic acid 3(C-Az)+ir''S" + nO (C'''A/.+II)+S'' KA/.0')+C'"II--0^ 2(S0'')+C"II'* c='ri? c'«ir'AzO> J C'fFAzC or \ { C'H'AzO^ C"IFiAz'iO'5 C'^II'O^+Chl'* C'll'+Iod'' C'IP+Iod C'lPO'^+Iod C^HHlod C'IF+Iod C-IFO+lilod C'^H''0^+Iod C^H+Iod'' C^H'O C'2H'"0 C'^LFO C'°H"0'<' cnio^ / Atnmlo wrighi. 54-73? 10-375 0-875" 20-25 21-25 ()-875 3-375 70-(i25 71-375 ll-(;25 13-75 23-028 7-375 15 18-8125 13-5 2-375? 18-375 15-378 lfJ-5 52-5 35 19-128 28-628 17-5 iy-375 18-75 29-375 48-875 4-5 21-375 9 11-25 9-75 8-5 18-875 22-5 6-125 lOfU APPENDIX. I ComiHMttlon. Atomie wtight Malic avid ("ll^O' 1''2li Malio other . c'lro-fCMi^o' ll'HT.^ MiuiiiiU' (jij|ii.().j 22-75 Marf;ari(' acid (7"'ir''()'' 70-25 Mar^aroiu' . . C'MI'^O :U)'5 Mnrji train, nil of .^rC'iiHO) i;j-3 Mocliloic acid L^HIHV" 2 1 -.{75 Mccoiiic acid . CMI^OT Pi-.') Mcconiii (;'"nH)« 12-128 Mclam . ("'II'iAz** ll-CtAlrt Mclaiiiiiic . . • C"H"Az" 15-75 Mcllitiu acid . C'lIO* 7-125 Melon .... C'\y.* 11-5 Mctiis|)crmiiia C"*II'^AzO^ 18-75 Mentha j>nlcj>;iui i, oil of . c'"ir 8-5 Menthu sativa, oil of :U(C"'ir) 29-75 Mei'captan (;'^ii«s+iis 7-75 Metacctonc , . . C'lIH) (;-i25 Mctaf>;allic acid cni'o' 12-H75 Mctaniarffaric acid . . (.7011.170'! (;(5-875 Mctanicconic acid . C'^'IPO'" iy-5 Methyl .... CHV 1-878 Methylene C^H'O 2-878 Methylic ethei' C^Il'O 2-875 Metoleic ucid (j70Hti4o« <)!>-5 Morjihina C3*H"*AzO'' 35-5 Mncate of methylene C»H«0+C''II'07 14-875 Mucic acid C«nH)7 12 Mueic ether . C)+HChl 32-(i25 Mm'iate of nu'thylcne C^IPO+IIChl 7-5 Mustard, volatile oil of, ) unnde of . . .J S'^4C"II'"Az20»l+Hiult>r Oil uf IciiioiiH Oil of niarjorain Oil of nicntha sativa Oil of miistartl Oil of jtarsloy Oil of ju'imyi-oyal . Oil of pepper . Oil r" pcppennint . Oil of potatoes Oil of roseniary Oil of roses Oil of sabiue . Oil of turpentine Oily chloride of naphthal Oleic acid Olein of Freniy Olein . . • Oleon Olivilin Orcein Orein Oxtti»t«- of nielamine Oxalhydric acid OxaJi*' acid Oxali»c ether . (Kalovinic acid Oxamethane . Oxamide Oxide of aldehydene Oxide of ethyl Oxychlorocarbonate of methylene . P I'araffin Puraninleic acid J*iir!iinucic acid I'aranuphthalin Parillina Compmlllon. I c'ii^o^-r'Mr^o' C H'O (""H'O c"*ir'()^+n ('...iiiMQrv c'n«o C^H^O 5(C"'H'')+0 S'iC'«H"'AzO»l cnv 2i(C'"ir)+2(no) C^Ii"() U(C'"H^)+-2(II0) C^'»II"0=' C"'H« C'lI'Chl 2{C^nv"on)^cnvo'>+2(uo) cnvKy C'lPAzO^ (:«H"Az<>+C^O^+IIO C^H»0« C^O' C'lPO+C^O' 2(C-0')+C»H50+HO CFFAzO"? C^O^+AzII'' C'H'O C'H^O C^H'O+C^ChlO' c ri^o? li(C'"H*) C"H»03 Aliimic wvlKhl, I I- 1 25 18-73 i>-25 I'ii 1 3-25 !>-6'25 u;-75 24 !»-25 4-8 11-25 8-8 43-5 2i»-75 22-5 fl-!>375 8-5 8-8 23-5 5-8 38-25 23-125 8-5 8-6 1-2-5 67-25 5-25 77-625 5iJ-5 ? 7-0625 20-75 19-75 21-375 •j-375 4-5 9-125 14-75 12-875? 5-5 4-378 4-628 11-875 0-875' 7 12 11-75 10-75 I I 10G6 APPENDIX. Parsley, oil of Parsley, oil of, camphor from Pasto resin Pectic acid Pennyroyal, oil of Pepper, oil of Peppermint, oil of Persian naphtha Petrol ene Phloridzin Phocenic acid Phosphovinic acid Picrotoxic acid Pinic acid Piperin . PoUenin of cedar Pollenin of lycopodium Potatoes, oil of Pseuderythrin Pyrocitric acid Pyrocitric ether Pyrogallic acid Pyromeconic acid Pyromucic acid Pyromucic ether Pyrotartaric acid Pyrotartaric ether Pyroxylic alcohol Pyroxylic spirit Pyruvic acid . Quassite Quinina Q R Racemic acid Racemomethylic acid Racemovinic acid . Resin of euphorbiuni Resin of gamboge . Resinein Resineon Resinon Ricinic acid . Roccellic acid Rosemary, oil of Rubinic acid . S Sabadilliiia Cumpnaitioii. Ciojjsoa C"H70'° C10H8 C10H8 2i(C"'H»)+2(HO) 2(PhO=2i)+C*H50 4(C'"H7*0) C*»H2»AzO« C'7H'7iO'» C*H«0 CSH^O* C0H3O3 C10JJ3O4 C10JJ3O5 C^HSO+C'"H='0'' C5H303 C^H^+HO C^H^O+HO C*H205 2(Ca, 844 sativum, 843 Almond, 890 Almonds, bitter, 101 volatile oil of, 469 oil of, 438 Aloes, 579 bitter principle of, 709 Althein, U3 Althionates, 170 Althionic acid, 169 Amber, 657 bitumen of, 560 u if 3z 1070 INDEX. Ambreic iiclil, I4S Ambrein, 145 Amrrican iiiRht abaito, 01 1 Amides, 0, MM) Amideti, 0, ftiW Atnidin. (&2 Aiiimclidc, 77!) Ammclin, 770 Aminoniar, Ao* AmmonU'ilchydc, .104 Amomum craiium paradisi, H91 zinRiber, 831 Ampclic acid, I(i7 Ariipclin, "i'.i'J Amygdalatcs, inci Amygdallc acid, lot Amygdalln, 471,692 A ii'yRdaliu communis, 8!)0 Amylaceous substances, 01!) AmyliniOal Anacardium .onjilfolium, !X)t Anchusic acid, 127 Andropogon schienanthus, 828 Anemoiiin, 500 Angustura vera, bark of, 811 Animalizcd matter, 753 Aiiimc, 543 Anise, 000 oil of, 475 Anotta, 417 Anthemis pyrcthrura, root of, 813 Anthiariii, 58!) Apocrcnates, 131 Apocrenic acid, 153 Apothem- 7u3 Apple, 8l>i Apricot, 8i)0 Arabic, gum, 073 Arabin, 071 Archil, aaa Areca catechu, 924 Aricina, 237 Aristolochia, grandi flora, 820 serpentaria, 828 Arnica montana, flowers of, 808 Arrow root, 050 Artemisia absynthium, 863 santoni5, 1040 hydiateof, 409 Coc.;ognidic acid, 910 Cocculus iiidious, lOU palmatus, 830 subcrosus, 914 Cnchlearia armorica, 8'27 ofKcinalis, 800 I'ocoa nut, 905 oil, 442 Cocos nuclfera, 905 I'odeina, 250 Ciilttca arabica, 917 Coflee,98, 917 ;;reen, 420 Colchicum autumnale, 845 Colocynthite, 709 Colop'han, 5U8, 525 Colnqui itida, 9(i7 Culonring matters, 307 red, 387 Coluinbin, 009 Columbo root, 830 Colza, oil of, 139 Compound acids, 108 Conicina, 2*0 Coiiiuin niaciilalum, S(i4 Convolvulus batata, 8 >7 lopa.va, 511 Co|>al, 543 varnish, 544 Cork, 798 Cornic acid, 104 (U)rnus Horlda, 837 Cortical layers, 799 Corydalina, 'i87 salts of, 283 Coltor, 850 Coumatii'. 703 Cow-tree wax, 448 Crameria triandra, 831 Crenates, 150 Crenie acid, 147 Creosote, 728 Croconic acid, 17 Crocus sativiis, 421 Croton cleutheria, bark of, 808 oil, 433 tiglium, 920 Crystallina, 291 Cucubin, S9() Cucumis colocynthis, 907 ■alivus, 908 Cudbear, 399, 40O Ciirova, 280 Curarina, 280 Curcuma longa, 419 V. urcumin, 420 Currant, black, 892 red, 892 Cusparin, 811 Cyanamide, 781 Cyanic acid, 209 ether, 313 Cyanllic acid, 211 Cyanogen and its com|x>unds, 207 chloride of, 7SU sulphuret of, 708 Cyanuric acid, 208 insoluble, 210 Cyclamen curopeum, 817 Cytizite, 700 U Dadyl, 456 n,nhlin, 000 Oammara, 538 Daphne gnidium, 910 mezcreum, 915 bark of, 805 Daphnin, 701 Date tree, pollen of, 871 Dates,' 925 Datiscin, 600 Datura stramonium, 909 Daturina, 270 Daucus carota, root of, 815 Deadly nightshade, 273 Delphina, 240 salts of, 247 Poitructive distillation, products of, 718 Ueutocarbohydrogen, 31(1 bromide of, 31 1 chloride of, 310 Deutoethionic ''cid, IflO Dextrine, 050, 007 Diastase, COO Digi. ..ma, 283 Digitilis purpurea, 857 Dill, oil of, 477 1) iosma crenata, 802 Discnses of plants, 940 Dracin, 538 Draconin, 5;)8 Dragon's blood, 537 Duni.isiri, 1402 Dutch iu,,lus, 931 Eblanin, 750 Elaidic acid, 430 ether, 345 Klaidin, 436 Klain, 127 Klaterii , 913 l';iateriunt,9ll Klatin,912 Klccamnane, S27 Klccampin, (MiO 1072 INDEX. Klcmi, 5.11 Elladic acid, P3 ] Emr linn, 202 Knmliiii, mi, 1040 Kpldcrmia, 71)7 Kquisctio aclil, .'i4 Kquiietum arvenap, 0^11 fluviatilc, ino hyemalc, D.'ll limnaum, 031 Ergot of rye, 879 Krvum lent, H88 Erythrln, 401 v Ewulic acid, SO E>enl)ekina, •JOi Ethal, 32] Ether, acetic. XH bpiuoic, SXi carbonic, 330 chiorncarbonic, .IVi chlnrocyanic, 'J^^ citric, 3;15 cyanic, 343 claidiCi 34& formic, aXV hydrocyanic, 32B malic, 335 niargaric, 346 mucic, 337 nitric, :<3() (cnanthic, 311 oleic, 34« oxalic, 333 pyrocitric, 338 pyromucic, 3.'il» pyrotartaric, 338 suberic, 34H ■uccinic, :<;)3 Eulphohydric, 3iS tartaric, 337 tliiaiic, im Ethcrcarbamide, 508 Etheroxamide, 33?, .'iBa Etheroxalatc of potash, .332 Ethers, 3!>t theory of, 8 Ethionic acid, 11)U Ethyl, 3^4 cyanodidc of, 3'i8 Eugenin, 4()!) Eupatorinar 3<)(i Eupatoriiim aya-pana, 8(i'J! Euphorbin, 7i)2 Euphnrbiiim, 57(> Eupion, 7S5 Extract, 702 Extractive, 702 V Fennel, oil of, 47fi Fermentation, 1015 Ferns, !•«) Flax, 849 Flowers, 807 blue and red, 380 red, 412 yellow, 423 white, 427 Formic acid, 17 Formo bcn/nilic acid, 206 Fossil wax uf Moldavia, 448 Foxglove, 8."i7 Fruits, 8*5 Fucus vcsiculosus, 045 serratus, SMri Fumaric acid, 57 Fungic acid, U30 Fungin, (!(i5 Fustic, old. 413 young, 422 Galactln, 448, 104'> Galbanum, .56!) Galipot, .525 Gallic acid, 8 V Gall-nuts, 108 (lamboge, .582 (J.irlir, 843 nil nf, 4S.1 Oasci in plantK, ~m (cratorla natruthiiiin,8l9 Imperatrln, H^ Innian rubber, (3IH IndlRO, 3 Mercaptan, 325 Mercaptidca, ;h!7 iNIcruliu!) cai\tliarcMus, 040 Mesembr ynnthcmum crystallinum, 800 J!esito, 30.) Metacetone,fl,'!5 Met.nmargaric acid, 122 Metameconic acid, 83 Metagallic acid, 88 Meta-olcic acid, 124 Methyl, 351 Methylene, .'151 Mujtercoii, 015 Milky juices, 701 Mint, cil of, 470 Misseltoe, OUi Momordica elatcrium,011 Morin, <. Morpi- 207 salts of, 271' Mould, . I'getabl", 070 Mucic acid, 77 ether, rm Mucilnge of lintseid, 073 Mucilaginous juices, 704 sugar, 014 ^fucin, 083 Musa paradi.'ica, 020 Muslirnonis, 430 Mustard, 002 oil of, 430 volatile oil of, 482 Jlyricin, 444 Myristica moschata, 013 scbifera, 014 Myrrh, .)75 Myrtle wax, 140 Myrtus pimento, 808 N Naphtha, coal, 720 Persian, 710 Naphthalamide, 30 Naphtiialan, 7+5 NaphthaUitcs, 20 Na|)hthalic acid, 27 etiier, 31 N.iphth.ilin, 738 oily chloride of, 74 solid chloride of, 7 10 Narceina. 248 Narcotina, 20.") sale I'f, 207 1074 INDRX. Nlcotlana tabacum, HM Nlciitianln, 4l)U Nicotiria, i(8l Nllranillc acltl. III NUrotiriizlilc, (IIU NlttoiiaphtlmLiiP, 7l.'i Nitroiia phtlmlciv, 711 Nitroaulphuric nuld, 7l>3 NutRalla, 1U7 Nutmeg, Oi:i butturnf, Itl oil of, 117 Nux vomica, 'J&^ Oati, S80 Onitea plchiirlm, iill Uilnanthlv ncid, l.'IS ether, ;IH Ull of almoiulH, 4:M bUtcr alnmulD, UW, 001 anUe, 'I7;> a»arui)i,479 baall, 480 bergamottp, 47'2 brandy, IS I cajcpiil, 47 fi camphor, iW> carawaya, 47S castor, 4110 chammnile, 477 cinnamon, 4<'t, WiO cloves, 4(i:>, IU4<1 cocoa nuts, H'i colza, l.'U) croton, 433 dill, 477 fennel, 476 garlic. 465 hem|i seed, 429 hops, 481 horseradish, 481 joni|uille, »7;) juniper berries, 4(i3 lavender, 474 laurel, 430 lemons, 450 lintseed, 4-^ mint, 47(5 mustard, 4;«l, 482 nutmegs, 477 olive, 434 orange floweri, 4(il palm, 440 parsley, 478 pepper, 4<)4 pep|)ermint, 47,) pimento, 47S potatoes, 481 rapcsee 1, 4Li8 rosemary, 474 roses, 47'i iabine, 46!) sassafras, 470' acurvy gr.'iss 485 tansey, 478 tea, 430 touloucnuna, 4tl turpentine, \:>.i wallnuts, 4iy whiskey, 461 Oils, fat, 433 fixed, 41J7 solid, 440 sweet, principle of, 61') vesicating, 482 volatile, 452, 1046 Oily acids, 120 Old tustic, 413 Oleic ether, 346 Olcin, 126,202 Olibanum, 574 Olive oil, 431 Olivllin,668 Onion, t Polychroitc, 421 PDlygaln nvncRa, HV) PolyRalic add, 1(1^ Polypoilium'flllx ma», IK'D vulgaro, Oao I'omcgrnnato, flill Poppv oil, 4:10 Poiiulln, 7110 Popiilua trrmuU, bark of, niO Potato nnntalna aolanhi, Mi oil, 4HI Polatoci, 8;i8 Prolo.cthionic add, 100 Pruniia cerasiu, 8811 Psciido.crylhrin, KO Piinica uranatum, H.'U Purple- of indigo, inil Purpurin, ;l!)l Pulcanic add, l.V! Putrefaction, KIM,') Pyraclds, theory of, 10 Pyro-acctlc spirit, ;i(12 Pyrocitric acid, (i2 ether, .'US Pyrogalllc add, 80 Pyroklnlr add, 0.1 Pyromecoiilc add, 8i Pyromucic add, 80 ether, aiii) Pyrotartaric add, l>;i ether, :i38 Pyroxanfhin, 7,'>' Pyroxyllc spirit, .')l(t Pyrus ciiinmunis, 8!)1 malus, 801 Pyruvic add, 65 Quasslte, -"5 2, 903 Sinapis, nigra and alba, 902 Smilacin, I;i7 Smllacina, 279 Smilax sarsaparllla, 831 Snake root, 828 Solanina, 264 Solanum lycoperslcum, 924 tuberosum, 8.'i8 Solorlna crocca, 934 Sophora Japanica, 867 Southernwood, flowers of, 69 Sowans, 651 Sow.wort, 817 Spermaceti, 323 Spiroil, 613 bromide of, 618 chloride of, 617 iodide of, 6IS Spiroilic add, 618 Spiroilides, 615 Squill, 845 Starch, 649 common, (}50 Staphysin, 757 Stavesacre, 2 10 Stearic acid, 122 Stearin, 122, 201 Stearr'ie, 122 Stcrculia acuminata, !)8 Storax, 537 1076 INUKX. ] Strychnio acid, 157 Ntrychiilna, VH:^ Mtyrnx, ll(iul>l, :>M HubiTlo otlicr, all) Hulwrlii, ~m Siibrcilii nranlmt' AI.1 SulMtltutliina, theory of, 1 1 Suciriiiiiinlilc, MU Succinic acid, WO Hucciia iiropriui, IO(iS Sugar, (WO of llBOt, (ViA common, lUO offlKK. )ll^ of ||rji|>ci, (KW liquid, (I;HI ll(|Uorlci-, l\U ■niiicovado, nti of inuihrouiiii, (I'll) rnw, (W^ rclirinl, aa of si arc! I, (130 Sumac, 4s!2, !>-<>3 flurinainliifl, V1N) Sulphamcthylanc, 361 iiulpliaiiiidc, ttiX) Sulphnhvnzldc, I'M, (111 Sulphucctic add, liKI, '.Ui HulphoKlyccrlv acid. IIKI Sulpho-liullRotic iicid, HIT Si' Iphuincthylatcs, IHO r jlphomethyllc acid, 17U 8ulpli(iiiaphlli4llc acid, IIU Sweet Hiig, t*js 8yringa cominunliii U^ T Tacamaliac, .'>:i.> Tamarindi, Hilli 'J'amarinduii iiiUii'ii, 81)0 Tanghlciii, \>M 'i'anfiliiiilc madagascnrcnili, S>2n Tannic acid, 107 'J'annin, 107 'I'aniey, oil of, ITS Tapioca, KtO Tartaric acid, (in ' Tartromothvlatcj, 1H8 Tartromcthyllc acid. 180 Tartrovinatcs, 17<) Tartrovinic acid, ITJ Tea, 858 oil,4S0 Tlita bohea and riridia, 8,'i8 Thebaina, '^U 'I'heina, liilS, 751) Theory of amidci, bcnzoll, 8 etiiere, 8 pyracidd, 10 subititutiojis, 1 1 Thiallc ether, :)«() Thorn apple, 901) TIlia Kuropxa, llowcrt of, 8CU Tobacco, SM Tolu, balsam of, 520 Tonlta bean, !K)7 'i'ouloiicouna oil, 440 Tragacanth, gum, (>7l Tremclla iioitoc, HH Trlticum, 87!) Trilo-ethlonic acid, 190 Truffles, 041 Tuber cibarium, 041 Tulipa tuaveolens, |X)llen of, 874 Turmeric, 419 Turnsole, 384 Turpentine, 500 common, AOA Cyprus, 511 French, 510 Hungary, 511 oil of, 45:) Strasburg, 510 Venice, 6(« Turkey red dyt-, y'.K". Typha latifolia, pollen of, 874 Ulinlcacid, IIU i;imln ofnnlac, 1M)I Upas, .vn anthlor, .'iW) lltMite, ,'i8H Urari. vHO Urcdo maldrs, OKI Urethan, 5UH Valerian, Hin Valeriana oHiclnalia, Hid Valerianatci, 'JH Valerianic acid, ,'U Vanill.1 aromatica. Oil Varnish, china, !>i^ Varnishes, 5(l.'l alculiol, 5(Vi oil of tur|ientlnc, Mi Variolaria amara, bitter principle of, 715 Vegetable princlplen, neutral, 500 substances, decompoilllon of, 100!) \'cgetatlon, l)4V Veratrliia, HU salts of, 1>U Verdic acid, 150 Vordous acid, 150 Vernis Martin, 514 Vicia faba, 88(1 Vinous ferment.ition, 1011 Violinn, W.i Virginuic acid, bW:j Virgin nil, 4^4 Viscin, (iH(> Viscum allium, 01(1 Vitis vinifcra, 81);» Vltrum, :ni Volatile oils, 452, 101^ containing oxygen, 4115 Vulpinic acid, 158 Vulpilin, 158 VV Walnut oil, 420 Wash, 1018 Wax, bees', 44,'J llrazil, 4^17 of ccroxylon andicola, 450 cowtrcc, 418 fossil of Moldavia, 448 Japan, 447 myrtle, 44(1 sealing, 55U Weld, 415 Wheat, rt7(i Whisky, oil of, 481 Wine, 1U22 Winter anacanella, bark of, 81 1 Woad, 8(iO Woods, 848 oxygen consumed by, 858 composition of, 819 Wormwood, 8(0 bitter principle of, 708 Woit, 1014 ' Xanthatcs, S04 Xnnthic add, 203 Xanthin, :I87 Xanthopicrite, 710 Xyloidin, Mi Yellow colouring matter, 412 Z Zei mays, pollen of, 87.1 seeds of, 883 Zein, CS5 (ilasgow;— I'rijitcd at the University Prcii, by E. Khull, (■ m 13 cr principle of, 715 neutral, 5(10 (locompoiltion of, 11)01) 1011 ng oxygen, Mj W idicoln, 450 /ia, 448 ark of, 811 jmcd by, 852 of, 819 inciple of, 708 X Y tcr, 412 Z )73 H3 :iiull.