Geology Library QD 87 B97p THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA LOS ANGELES Tke RALPH D. REED LIBRARY DEPARTMENT OF GEOLOGY UNIVERSITY of CALIFORNIA LOS ANGELES, CALIF. of Oil Companies of Southern Cali- fornia, Alumni and Faculty of Geology Depart- ment and University Library. 1940 //' M r r o e is/, I i- i. / *J o i <>. WORKS OF PROF. G. MONTAGUE BUTLER PUBLISHED BY JOHN WILEY & SONS A Pocket Handbook of Minerals. Designed for Use in the Field or Classroom, with little reference to Chemical Tests. Second Edition. x6mo, ix-t-3ii pages, illustrated. Leather, $;.oo. Pocket Handbook of Blowpipe Analysis. Designed for the Use of Students and Prospectors with the idea of making Oral Instruction unnec- essary. i6mo, v+8o pages. Cloth, js cents net. POCKET HANDBOOK OF BLOWPIPE ANALYSIS DESIGNED FOR THE USE OF STUDENTS AND PROSPECTORS WITH THE IDEA OF MAKING ORAL INSTRUCTION UNNECESSARY BY G. MONTAGUE BUTLER, E.M. Assistant Professor of Geology and Mineralogy. Colorado School of Mines Golden, Colorado; Geologist, Colorado Geological Survey FIRST EDITION FIRST THOUSAND NEW YORK JOHN WILEY & SONS LONDON-: CHAPMAN & HALL, LIMITED 1910 Copyright, 1 9'. BY G. MONTAGUE BUTLER THE SCIENTIFIC PRESS PREFACE THIS little book was written, primarily, to satisfy the demands of those instructors who have been using the author's Pocket Handbook of Minerals as a text-book for courses in mineralogy. While there is no doubt that a thorough knowledge of the physical characteristics of minerals should be the end sought by all teachers and students of this subject, it is often desirable to be able to fall back upon other simple tests in corroboration of conclusions reached by observation, or when studying an unfamiliar mineral. For this purpose, blowpipe analysis is very satisfactory, since the necessary implements and reagents are comparatively few and simple and may be so selected as to be portable. While there are many works on this subject, 1 they are either too comprehensive for the purpose for which this is intended, or else form merely an ! introductory chapter to a work on mineralogy. In I both cases, their purchase entails a needlessly high expense, and their directions and statements are ! often so vague and incomplete as to require continual - explanation by an instructor. iii 733801 iv PREFACE No originality is claimed for the tests themselves as given in this pamphlet; they are the same as are included in all books on the subject, and as have been taught in the Colorado School of Mines for years by Professor H. B. Patton. Such modifications and additions have been made, however, as experi- ence has proven desirable. The text and plan of the work are, of course, original, and so are most of the data included in the notes on the various tests. Utility and conciseness have been the ends sought, and it is believed that no superfluous details have been included and that nothing essential has been omitted. Secondarily, the book was written to satisfy the needs of miners and prospectors, whose first question on finding a new mineral is, "What does it contain ?" It is so elementary in its nature and the directions are so complete that anyone with a common-school education, the proper instruments, and this book should be able in most cases to answer this question for himself. It was for this class of readers alone that Chapters V and VI were included. Finally, it is believed that assayers and chemists will find the book useful in making preliminary examinations of unknown substances. TABLE OF CONTENTS CHAPTER I PAGE BLOWPIPE INSTRUMENTS, REAGENTS AND OPERATIONS i CHAPTER II METHODS OF TESTING FOR THE VARIOUS ELEMENTS WITH THE BLOWPIPE 9 CHAPTER III OUTLINE FOR QUALITATIVE BLOWPIPE ANALYSIS 42 CHAPTER IV INDEX TO ALL OF THE TESTS YIELDED BY THE VARIOUS ELEMENTS 47 THE DETERMINATION OF MINERALS BY MEANS OF THE BLOWPIPE 50 CHAPTKR VI THE ELEMENTARY PRINCIPLES OF CHEMISTRY 62 TABLE OF ELEMENTS WITH THEIR SYMBOLS AND ATOMIC WEIGHTS 73 INDEX . 74 BLOWPIPE ANALYSIS CHAPTER I BLOWPIPE INSTRUMENTS, REAGENTS AND OPERATIONS NEARLY all dealers in assayers' or chemists' sup- plies cany sets and separate pieces of blowpipe apparatus, and many pieces may be obtained elsewhere, as will be seen from the following brief description of the articles used in the operations later described. Most of the sets now on the market are either too elaborate, too bulky, or else are impractical, and great care should be exercised in their selection. Blowpipe. Many types are manufactured, and each may have its own peculiar advantages, but almost any one in which the aperture is not too large or too small will answer the purpose. The most satisfactory type has a trumpet-shaped mouthpiece, a small chamber in which the saliva may accumulate, and a removable tip. In portable sets it is not practicable to provide a blowpipe with a trumpet-shaped mouthpiece, however, and 2 BLOWPIPE A. \ A LYSIS this may be dispensed with, although somewhat easier on the lip muscles. Some makes are pro- vided with platinum tips, but this is an unnecessary refinement unless a great deal of work is to be done. A piece of very fine platinum or steel wire is the best implement with which to clean out a clogged tip. Lamps. It is desirable, although not absolutely essential, to have two lamps, one for oil and the other for alcohol. The latter is handier than the oil lamp for a few operations which will be men- tioned later, but in every case it can be replaced by the oil lamp without material disadvantage. The oil lamp should have a rectangular wick opening about half an inch long and less than half as wide; the wick opening in the alcohol lamp may be of any shape. Care should be taken (par- ticularly " with the oil lamp) not to have the wick so tight as to impede the flow of oil, to trim off charred wick or irregularities as fast as they form, and to keep the wick just high enough not to smoke. The best fuel for the oil lamp is a mixture com- posed of two parts of lard oil and one part of kero- sene. This solidifies in very cold weather, but thaws out soon after lighting the lamp. Any other flame, such as that from a candle or kerosene lamp, may be used instead of these lamps, and it is often necessary to resort to these in the field, but the lamps and oil described will INSTRUMENTS, REAGENTS, OPERATIONS 3 give the best results in the laboratory. In some places gas blowpipes are used, but one who has attained proficiency with such apparatus is lost in the field, so simpler instruments are preferable. Platinum-tipped' Forceps. The most convenient type of these has tips of platinum on one end and of base metal on the other, the platinum-tipped end being provided with a spring which holds the tips together. Precautions as to the use of these forceps are given later. They soon become discolored with use, but, if the precautions just mentioned are observed, this will not harm them. They may be cleaned by using very fine sandpaper or scraping with a knife-blade. Platinum Wire and Holder. The wire should be of about 26 American or B. & S. Wire Gauge in thickness, and should be cut into pieces between two and three inches long. The holder may be a glass tube into which one end of the wire is fused, but a mechanical holder with a hollow handle in which extra wires may be kept is more convenient. Precautions concerning the use of the platinum wire are given later. Charcoal Supports. These should be made from soft wood and should be at least three inches long, preferably more. They should not fissure, break, smoke, or ignite readily in the flame, and should leave little ash when burned. Unless liquid reagents have been used on the 4 BLOWPIPE ANALYSIS charcoal in tests resulting successfully, the charcoal may be used many times by scraping oil the surface and the deposits formed thereon. Where liquids have been used in successful tests, they are apt to sink for a considerable distance into the charcoal, and to cause a duplication of the test even after a considerable depth of the charcoal has been removed. Closed Tubes. These are usually formed of three-eighths inch glass tubing three or four inches long, an inch of one end being bent to one side and closed by fusion. Equally satisfactory results are secured from an implement formed by fusing together one end of an open tube (see below). Closed tubes cannot well be cleaned and should be discarded after use. A strip of asbestos, or even paper, wrapped around the upper part of the tube makes a convenient holder for hot tubes. Open Tubes. These are pieces of three-eighths inch glass tubing three to five inches long. They should be discarded after use unless the results have been negative, when the other end may be used for a new test. The asbestos or paper holder mentioned above should be used for hot tubes. Miscellaneous. A small slab of hard steel with at least one polished surface for use as an anvil. A small steel hammer with a flat face. A small horseshoe or bar magnet. The latter may be procured with one end so shaped as to INSTRUMENTS, REAGENTS, OPERATIONS 5 form a charcoal borer, but this is not neces- sary. Test-tubes. A hand-lens. A small piece of dark blue glass. Reagent Bottles and Reagents. Wide-mouth, glass- stoppered bottles are the best in which to keep the dry reagents, which should include powdered (pref- erably dehydrated) borax, sodium carbonate, sodium ammonium phosphate (salt of phosphorus), acid potassium sulphate, and bismuth flux (equal pro- portions of potassium iodide and sulphur). The wet reagents should be kept in glass bottles with glass stoppers, and a dropper stopper will be found a great convenience, although a satis- factory dropper can be easily made from a small glass tube. The following reagents are needed: Hydrochloric (muriatic) acid. The concentrated acid should be diluted with an equal volume of water for most purposes. Xitric acid. The concentrated acid is usually employed. Sulphuric acid (oil of vitriol). For most purposes the. concentrated acid should be diluted with four volumes of water. A great deal of heat is generated when water and sulphuric acid are mixed, and this should be done with care. The acid should be added gradually to the water, stirring constantly. Water should never be added to sulphuric acid. 6 BLOWPIPE ANALYSIS Cobalt nitrate. The dry salt should be dissolved in ten parts of water for use. All acids should be handled with care, as they are more or less corrosive and are capable of inflict- ing painful injuries when spilled on the skin. When this happens, or if they fall upon fabrics, their effects may be neutralized by moistening with ammonia and then washing thoroughly with water. Blowpipe Operations. The blowpipe is used for the purpose of concentrating the flame into a long, slender cone which can be readily directed against the substance to be heated. It is very important that the blast be continuous and uniform, although this may seem very difficult at first. The blast is not produced by the lungs, but results from a bel- lows-like action of the distended cheeks. During the operation, air is inhaled only through the nose, and is exhaled largely through the mouth and the blowpipe. Before trying to use that instrument, distend the cheeks, and, keeping the mouth closed, breathe through the nose for a moment; then open the lips just enough to allow a little air to escape slowly, and admit air from the lungs by a kind of gulping action just fast enough to keep the cheeks fully distended. This may take some practice, but, when it is possible to allow air to escape con- tinuously from the mouth in this way no matter whether it is being exhaled or inhaled through the nostrils, it is time to begin to use the blowpipe. INSTRUMENTS, REAGENTS, OPERATIONS 7 Producing the Oxidizing Flame. Place the oil lamp so that the longer dimension of the wick is from right to left, and set its right-hand edge upon a pencil or some other low support so that it will tip somewhat to the left. Insert the tip of the blow- pipe about one-eighth of an inch within and just above the right-hand side of the wick, and blow steadily parallel to the wick, directing the flame to the left, and producing a clear blue flame about an inch long. If all of the flame cannot be thus diverted to the left, or if there are yellow streaks in the flame, trim or lower the wick. If the whole flame is inclined to be yellow, move the tip of the blowpipe a trifle to the left. If it is impossible to produce a flame approaching the length mentioned above, the opening in the end of the blowpipe is too small, and this opening is too large when a very long, hissing flame is produced. In order to succeed in blowing a steady flame, the hand must rest upon some support, or the third and fourth fingers may be placed against the lamp. IP analytical operations it is sometimes desirable to oxidize substances to be tested, and at other times the aim is to reduce them to the metallic condition; either result can be more or less readily obtained with the blowpipe. ( A flame produced in the manner above described is called an oxidizing flame, but the action of all portions of such a flame is not oxidizing. The blue 8 BLOWPIPE ANALYSIS cone contains considerable carbon monoxide and is feebly reducing in its action, but just outside of the blue cone at the tip of the flame is an extremely hot but nearly colorless zone which is strongly oxidizing because of the free oxygen there present, and anything held in this zone about a quarter of an inch from the tip of the blue flame will be in the most favorable position for oxidation. The oxidizing flame is hotter than the reducing, and the hottest part of this flame is just outside of the blue cone. In the absence of other instructions, substances should always be heated there. Producing the Reducing Flame. Hold the tip of the blowpipe about one-sixteenth of an inch above and to the right of the wick, and a long, yellow flame containing much unconsumed carbon will be produced. This is sometimes called the smoky reducing flame. Where greater heat is required, the inner cone of the oxidizing flame should be used. The strongest reducing action will take place at the tip of, and within, the yellow cone of the reducing flame. Other Operations. These will be described in detail when the various tests are discussed. CHAPTER II METHODS OF TESTING FOR THE VARIOUS ELEMENTS WITH THE BLOWPIPE THE methods of testing for the various elements with the blowpipe comprise blowpipe analysis, and many tests are included under this term, includ- ing a few in which the blowpipe is not required. The most useful are included in the following list, and will be discussed in the order named: I. Treatment on charcoal without flux. II. Treatment on charcoal with flux. III. Tests in closed tubes. IV. Tests in open tubes. V. Tests with borax beads. VI. Tests with salt of phosphorus beads. VII. Flame tests. VIII. Cobalt nitrate coloration tests. IX. Tests with acids. The tests given should make it possible to recog- nize the following elements and substances in most of their combinations: Aluminum (Al), antimony (Sb), arsenic (As), barium (Ba), bismuth (Bi), boron (B), cadmium (Cd), calcium (Ca), chromium (Cr), cobalt (Co), 9 10 BLOWPIPE ANALYSIS copper (Cu), flourine (F), gold (Au), iron (Fe), lead (Pb), lithium (Li), magnesium (Mg), manganese (Mn), mercury (Hg), molybdenum (Mo), nickel (Ni), phosphorus (P), potassium (K), selenium (Se), silver (Ag), sodium (Na), strontium (Sr), sulphur (S), tellurium (Te), tin (Sn), titanium (Ti), tung- sten (W), uranium (U), vanadium (V), zinc (Zn), and water, silicates, and carbonates. i. TREATMENT ON CHARCOAL WITHOUT FLUX A piece, the size of a BB shot or smaller, of the substance to be tested is pressed into the face of the charcoal about half an inch from one end, or it may be placed in a tiny cavity formed at that point, the object of embedding it somewhat in the charcoal being merely to prevent the particle from sliding off or being blown away. The charcoal is then held in the left hand, pointing right and left, and the blowpipe flame is blown upon the particle, which should be at the right end, in such a manner that the flame is not parallel with the charcoal but impinges downward upon the particle at a small The piece tested is known as the assay. Heat the assay strongly for a minute or more in the oxidizing flame, noting any odor or colored flame that may be given off, and then examine the charcoal for any coatings, known as sublimates, that METHODS OF TESTING 11 may have been deposited thereon. If no very positive results are thus obtained, repeat the opera- tion, using the reducing flame. Care must be taken not to place the assay in deep holes that have been burned or scraped into the charcoal. If this is done, the volatilized material will shoot up into the air, and no sublimate will deposit on the charcoal. Most charcoal forms a little white ash when burned; this should not be confused with a sub- limate. Decrepitation (flying to pieces) of the assay may sometimes be prevented by heating it very slowly, i.e., holding it three or four inches from the flame at first and gradually bringing it nearer. Another method, often satisfactory, consists of blowing the flame against the upper part of the end of the stick of charcoal until it is red hot, thus gradually warming the assay. If the substance still decrepitates or if no results are obtained by the above methods of treatment, powder the material to be tested very fine and press a small amount of the powder onto one end of the charcoal, using a knife blade or spatula for this purpose and forming a flat cake of the powder. Then proceed as before. If the material still decrepitates, moisten it with water and heat very slowly. Since chlorides of lead, copper, and other sub- 12 BLOWPIPE AX. -I LYSIS stances yield white sublimates on charcoal that may be confused with those mentioned below, it is essential that the charcoal tests be made before any hydrochloric acid has been put on the substance to be tested. Not only is it necessary to note the color of any sublimates produced, but their volatility should also be tested, as some are very volatile (can be burned off by applying the blowpipe flame for a fraction of a second) while others are quite non-volatile (require the application of considerable heat to entirely remove them) in the oxidizing flame, which should be used for this test. The results obtained by any of the above means may be thus interpreted: a. White, very volatile, light sublimate, depos- ited some distance from the assay. Strong odor of garlic As b. White sublimate with a blue border deposited close to the assay, heavier and less volatile than that yielded by As. Assay will often continue to give forth white fumes after heating has ceased Sb c. White, fairly easily volatilized, heavy sub- limate near the assay, shading into a lighter, more volatile coating further out. Odor of garlic Sb with As METHODS OF TESTING 13 d. White and yellowish, crystalline (particles are coarse and sharp-edged) sublimate which is changed to a deep ultramarine blue if touched for a, fraction of a second with the reducing flame. A copper-red coating may form close to the assay Mo (Prolonged heating with the oxidizing flame is required to obtain the white sublimate, which is yielded satisfactorily only by the sulphide molyb- denite.) e. White when cold, yellow when hot, light, non-volatile sublimate, which, if moistened with cobalt nitrate and heated, will become bright green when cold Zn (This test should be conducted as follows: Pul- verize the material very fine and heat strongly and for some time with the reducing flame; moisten the charcoal where the sublimate has formed, or should form, with a little cobalt nitrate; reheat the assay strongly with the reducing flame, and, if Zn be present in any form but the silicate, enough heat will reach the spot moistened to turn it bright green when cold.) /. White, heavy sublimate with a blue outer border close to the assay, a yellowish gray coating far from the assay, and a black band between the two. All are easily vola- tile, burning off with a light bluish green flame, which is also yielded by the assay Te g. White when cold, yellowish when hot, light, 14 BLOWPIPE ANALYSIS non-volatile sublimate, which, if moistened with cobalt nitrate and heated, will become a dull bluish green when cold Sn (This test should be conducted exactly like the one for Zn, described above.) I* h. Yellow, volatile sublimate, inclining toward orange when hot, with a very volatile outer fringe of white. Yellow fumes and odor of garlic As with S (This result is obtained when a sulphide of As is heated and volatilized too rapidly to permit of com- plete oxidation. Some of the material is volatilized and deposited as the yellow sulphide of As.) i. Yellow or orange, non-volatile sublimate, often with a bluish white outer border, deposited very close to the assay Pb j. Yellow or orange, non-volatile sublimate, often with a bluish white outer fringe, deposited very close to the assay Bi (Bi is much rarer than Pb, and the test described alx)ve may in the majority of cases be interpreted as indicating Pb. To distinguish with certainty between these two elements, mix the powdered sub- stance with three or four times its volume of "bis- muth flux" (equal proportions of potassium iodide and sulphur), and heat on charcoal as usual. The sublimate produced by Bi will be yellow near the assay, but bordered on the outer edge by a brilliant red, which will be missing in the case of Pb.) k. Brown, volatile sublimate close to the assay, METHODS OF TESTIXG 15 bordered by a very volatile, heavy white sublimate. Odor of garlic As (This result is obtained when the material is heated and volatilized too rapidly to admit of com- plete oxidation ojpthe As. The brown sublimate is metallic As.) I. Brown, fairly volatile sublimate close to the assay Cd m. Reddish brown outer border on a black or steel-gray volatile sublimate. A curious and indescribable, but characteristic, odor and a blue flame Se n. Lilac or lilac-red, volatile sublimate. .Ag with Pb o. Blue flame and a suffocating pungent odor. . S (Se, Te, Cu chloride, and other substances burn with a blue flame, but the blue flame combined with the odor is distinctive of S.) p. Magnetic residue left on charcoal . . .Fe, Ni, or Co (If the assay is infusible does not melt a mag- netic residue indicates Fe.) II. TREATMENT ON CHARCOAL WITH FLUX This test is used when it is desired to reduce a salt to the metallic condition, so the reduction flame is employed. The substance to be tested is finely pulverized and mixed thoroughly with about three times as 16 BLOWPIPE ANALYSIS much powdered sodium carbonate and a little powdered borax. The mixture is then pressed into a cake at one end of the charcoal and thoroughly fused, beginning at the edges and working toward the center. A little powdered. charcoal thoroughly mixed with the material to be fused will often facilitate the reduction. If the assay will not fuse down to a liquid mass, either the amount of flux (sodium carbonate and borax) or of heat applied is deficient. In the latter case, raise the lamp wick and trim off the coal that forms upon it. It is almost useless to hope for satisfactory results until a continuous blast can be blown. Sometimes a fusion that appears to have come to a standstill may be successfully completed by allowing the assay to cool, removing the little cake of semi-fused material with the point of a knife, turning it upside down on the charcoal, and proceeding as at first. Some charcoal usually adheres to the upper surface of the cake and this has a strong reducing influence. This process is always necessary in the case of Sn. Metallic Sb and many sulphides and arsenides yield metallic globules by this test, but these are distinguishable by their brittleness from those described below. In addition to sublimates identical with those that form on charcoal without flux, other results are produced which may be thus interpreted: METHODS OF TESTING 17 a. White when cold, yellow when hot, light, non-volatile sublimate, which, if moistened with cobalt nitrate and heated, will become bright green when cold Zn (Zn compounds which give this test with diffi- culty or not at all when treated without flux will give a good color when flux is used. The operation should be conducted as described under I.e. Care should be exercised not to confuse the green Zn coloration that appears in front of the assay with a blue color on the assay itself. The latter will appear whenever fusible material is moistened with cobalt nitrate and heated, regardless of the presence or absence of Zn.) b. Lilac or lilac-red, moderately volatile subli- mate and a white, malleable, metallic button Agwith Pb c. Yellow or orange, non-volatile sublimate, often with a bluish white outer border, deposited very close to the assay, and a mal- leable, metallic button, grayish white on a freshly cut surface but oxidizing on expos- ure to the air Pb d. Yellow or orange, non-volatile sublimate, often with a bluish white outer border, deposited very close to the assay, and a rather brittle, metallic button, grayish white on a freshly cut surface but oxidizing on exposure to the air Bi (The button may flatten somewhat when first hammered but is not malleable like Pb. This will 18 BLO\YPIP1: ANALYSIS usually suffice to distinguish between the two metals, or the test with " bismuth flux," described under I./., may be applied.) e. White, malleable, metallic button Ag (To distinguish between Ag and Pb buttons, place the button to be tested in a small depression on a clean piece of charcoal and heat strongly in the oxidizing flame. If Pb, the characteristic yellow sublimate will form, and, if Ag, there will be no coating or only a faint brownish one. The two metals may also be distinguished after some practice by the fact that the Ag is decidedly harder; the flattened button may be cut only with difficulty while Pb cuts easily.) /. White, malleable, metallic buttons of small size, which show little or no tendency to coalesce into one large button. A white when cold, yellowish when hot, light, non- volatile sublimate may also form Sn (To distinguish between Sn and Ag, remember that the latter forms one large button, usually, while the many small buttons of the former can be forced to coalesce only with great difficulty and after prolonged blowing. Another method of dis- tinguishing them is to alloy the button in doubt with a somewhat smaller amount of Pb, by melt- ing the two together, and then to note whether the characteristic lilac Ag-Pb sublimate is produced in the oxidizing flame. A third method involves an endeavor to secure the sublimate and cobalt nitrate color reaction of Sn as described under I.g.) g. Yellow, malleable, metallic button Au //. Red, malleable, metallic mass, which it is METHODS OF TESTIXG 19 impossible to fuse into a single button by means of the blowpipe Cu i. Gray, malleable, magnetic particles (not globules) Fe, Co, or Ni (The three may be readily distinguished by the "bead tests" (V.),q.v.) ;'. The thoroughly fused mass forming the assay, when placed on a clean, moistened silver surface, produces a dark brown or black stain S, Te, or Se (This test is very delicate, but it must be made carefully in order to succeed. Exactly three parts by volume of sodium carbonate must be used for one part of the substance to be tested, and it is best to press the fused mass with a knife or hammer- head against the silver surface which has previously been moistened with a drop of water, and to hold it there for a minute or two. Sometimes a slight stain which may be rubbed off with the fingers or washed off with water is produced. This should be ignored, as the S, Te, or Se stain is permanent. Unless Te or Se have been detected by tests I/, l.m., lll.c., III./., III./., III.o., IV.g., or IV. k., the presence of a dark stain on the silver may be assumed to indicate S.) III. TESTS IN CLOSED TUBES It is sometimes desirable to treat the substance just as it is, while for other tests it is best to mix it with three or four times as much sodium carbonate or acid potassium sulphate. In any case, the whole charge should be powdered as fine as possible and 20 BLOWPIPE ANALYSIS enough introduced within a tube to fill it to a height of about half an inch. This may be done with a small paper or tin funnel or chute, or even with a very small knife blade. The lower portion of the tube and the charge contained therein should then be heated to redness for some time and the results noted. An alcohol flame alone may be used for this purpose, but the work may be hastened and the results often improved by using the blowpipe on the alcohol or oil flame. Care must be exercised not to use too high a heat or the glass will melt, swell, and break open, or will completely seal up the charge. Possible results obtainable without flux are as follows : a. Moisture in drops on the walls of the tube a short distance above the charge H 2 O b. Liquid, mirror-like sublimate that collects in globules Hg (Only the native metal will give this result with- out using sodium carbonate flux.) c. Mirror-like sublimate of large and small, solid, white globules Te d. Mirror-like sublimate of very small, solid, white globules Cd (Cd and Te are easily distinguished by using tests I./, and I.I.) e. Mirror-like, solid, black sublimate, often with dull black sublimate above, both volatile As METHODS OF TESTIXG 21 (A sulphide will not yield this result without using sodium carbonate flux.) /. White sublimate composed of tiny globules in a narrow zone immediately above the charge, with a ring of yellow globules or liquid at the base, both very slowly vola- tile Te (Tests III.c. and III./, are given by different ores of Te or are the result of the application of dif- ferent temperatures.) g. White, faint, very slowly volatile sublimate with a little yellow liquid close to the charge . . Sb (A sulphide will not yield this result without using sodium carbonate flux.) h. Reddish liquid when hot, yellow solid when cold; may be almost white when cold if the amount is small S *. Dark red liquid when hot, orange solid when cold As with S ;'. Black when hot, reddish brown when cold, difficultly volatile sublimate Sb with S k. Black, volatile sublimate. If the tube is broken and the sublimate rubbed with a cloth, it will sometimes turn red, but this is unusual Hg with S /. Black, difficultly volatile sublimate, composed of irregularly shaped drops, liquid when hot. Shades above into a volatile sublimate, 22 BLOWPIPE ANALYSIS reddish brown when hot and dark red when cold Se Possible results obtainable with sodium carbonate flux are as follows: m. Moisture in drops on the walls of the tube a short distance above the charge H 2 O n. Liquid, mirror-like sublimate that collects in globules Hg o. Mirror-like sublimate of large and small, solid, white globules Te p. Mirror-like sublimate composed of very small, solid, white globules Cd (Cd and Te are easily distinguished by using 'rsts I./, and I.I.) q. Mirror-like, solid, black sublimate, often with a dull, solid, black, sublimate above, both volatile As r. White, faint, very slowly volatile sublimate with a little yellow liquid close to the assay Sb Possible result obtainable with acid potassium sulphate is as follows: s. After boiling the contents of the tube vigor- ously for several minutes, the glass immedi- ately above the charge is etched or rough- ened F (This result is most easily recognized by breaking METHODS OF TESTIXG 23 the tube, washing the interior thoroughly, and then scratching the portion that may be etched with the point of a knife. If etching has occurred, the surface will feel much rougher than does unetched glass.) IV. TESTS IN OPEN TUBES No flux is used in these tests. The substance to be treated is merely finely powdered, a little of it is placed about half an inch from one end within a tube, and it is then heated strongly while the tube is held as highly inclined as is possible without losing the charge. The alcohol flame may be used, but as good or better results are produced by the oil flame and the blowpipe. In fact, the greater heat of the blowpipe-concentrated oil flame is essential for some of the tests, and this should always be used after securing negative results with the alcohol flame. The tests are very delicate, but are ordinarily used only to corroborate unsatisfactory charcoal tests. Possible results may be thus interpreted: a. Moisture in drops on the walls of the tube. . H 2 O b. Characteristic, suffocating, pungent odor... S c. White, light, very volatile, crystalline subli- mate, and odor of garlic As d. White, heavy sublimate, less volatile than 24 BLOWPIPE ANALYSIS that given by As, and dense white fumes. Slender white crystals may form on the charge if the heat is not too great Sb e. White when cold and light yellow when hot, very heavy, almost non-volatile sublimate and very dense white fumes which pass along the under side of the tube. If a large amount of material be heated very intensely, a little difficultly volatile sublimate, black when hot and reddish brown when cold, may form Sb with S /. White, faint, non-volatile sublimate disc to charge Pb with S g. White, slowly volatile sublimate, which fuses to globules which are yellow hot and color- less cold. Often, yellow globules form around, and a gray sublimate collects above the charge Te h. White, non -volatile sublimate, fusible to yellow drops, lighter when cool Bi with S (Bi with S and Te are readily distinguished by tests I./, and I.;., the latter being characteristic of Bi no matter in what combinations it may be.) i. White, delicate crystals, yellow when hot, form near and over the charge after pro- longed heating Mo ;. Yellow, volatile sublimate, inclining toward orange or red when hot, with a very volatile METHODS OF TESTING 25 outer border of white. Yellow fumes and odor of garlic As with S (This result is often produced when a substance containing S and As is heated too rapidly to allow of complete oxidation.) k. Black, volatile sublimate where very heavy, which shades toward the upper end of the tube into a volatile coating that is reddish brown when hot and dark red when cold. A curious and indescribable but character- istic odor and lilac fumes, best seen against a black background Se /. Black, /ery volatile sublimate with brownish or iridescent bands and sometimes a mirror- like deposit close to the charge. White fumes, a white volatile sublimate beyond the black, and characteristic odor of garlic. As (This result is produced when a large amount of material is heated too rapidly to allow of complete oxidation.) V. TESTS WITH BORAX BEADS The beads are made by heating the end of a platinum wire to redness, dipping it into some powdered or granulated borax, reheating the wire and adhering borax, and continuing the process until the bead when thoroughly fused is as large as will remain on the wire. If too small, the color is hard to see, and a bead that is too large will keep 26 BLOWPIPE ANALYSIS falling from the wire. Some of the oxidizing flame tests may be made with the alcohol flame, but all may be secured more quickly and easily with the oil flame and the blowpipe. The bead should always be kept at the end of the wire, and this may be done by bending the end of the wire and holding it in such a manner that the blowpipe flame is always directed against the side of the bead furthest from the end, forcing it to the end. A loop to hold the bead should not be formed in the wire; it is unnecessary if the wire is clean, and uses up the platinum very rapidly. Before making any bead test, the material to be tested should be powdered and thoroughly roasted on charcoal. This is accomplished by spreading the powder on the surface of the charcoal in a flat cake, so as to allow free access of air, and heating to a dull red in that part of a small oxidizing flame that is well outside of the blue cone. The reducing flame should then be applied, and, finally, the oxidizing flame used until no odors of As or S are apparent and the assay ceases to burn with a colored flame or to volatilize. Fusion should be prevented if possible. This may be accomplished by mixing the fusible substance with about an equal volume of powdered charcoal, which keeps the particles separated and soon burns away. No satisfactory bead tests need be expected from a substance which volatilizes completely without solidification. METHODS OF TESTING 27 To make the tests, heat the bead as hot as possible and touch it to a very little (a few grains) of the powdered substance to be tested. Some of the latter will adhere to the bead, which should then be heated in the oxidizing flame and any resulting change of color noted. This process should then be repeated on the same bead, using the reducing flame. If the results are negative or too faint to be decisive, more of the powder should be dissolved in the bead and the process continued until a rela- tively large amount has been added, when the bead is said to be saturated. The colors of the beads are due to the presence of oxides of the various elements, and these oxides vary greatly in their coloring powers. In some cases, deep, vivid colors are obtained from a few grains of the powdered substance, while in other instances it is necessary to dip the bead many times into the powdered substance before the character- istic colors are produced. Beads in the former class may be considered saturated when the color is so deep as to make them practically opaque; those in the latter class are saturated when they refuse to absorb more of the material. This may require half a dozen applications of the powder. In case a bead becomes so saturated upon the first application to the powder that its color is indeterminate, it may be flattened upon the anvil while still warm and the color readily observed in 28 BLOWPIPE AX A LYSIS the thin cake thus formed. This cake may then be broken into many pieces, and a few of these added to a fresh bead without saturating the latter. All beads, even when saturated, should be perfectly clear unless otherwise noted. If this is not the case, a higher heat should be applied or new beads formed, as a bead that has been worked with for some time in different flames is apt to become translucent or opaque. It should be remembered that a bead containing incompletely roasted powder is very apt to be, brown in both flames, and then prolonged heating is required to expel the S or other interfering element or elements. The bead test should never be used on a substance suspected to contain Cu, as that element will alloy with the platinum and give Cu beads whenever the same wire is used in subsequent tests. Other elements are apt to alloy- with the platinum, par- ticularly during the formation of reduction beads, and these will make the wire brittle and cause it to break easily, but will not interfere with tests made before the break occurs. To remove a bead from the wire, either break it off on the anvil or jar it off while in a molten con- dition. When the latter method is used, it is a good idea to save the beads obtained from known substances and compare them with those given by unknown materials. METHODS OF TESTING 29 The most difficult operation involved in making the bead tests is the production of a good, con- tinuous reducing flame, yet this is very im- portant and must be mastered. Manganese gives a very highly colored bead in the oxidizing flame, and the production of the colorless bead in the reducing flame is a good test of ability in this line. If a substance contains two elements each of which yields a characteristic bead, one may so modify the other as to give intermediate results. However, in most cases of this kind, one color will completely mask the other, and this makes it then impossible to detect both elements. The accompanying table indicates the colors of the borax and salt of phosphorus beads (see below) yielded by the elements named in both oxidizing and reducing flames. The following abbrevia- tions are used: O.F. = oxidizing flame. R.F. = reducing flame. W = warm bead. *= saturated bead. C = cold bead. As an illustration, consider iron. The table shows that iron gives in the oxidizing flame a borax bead that is yellow while warm and colorless when cold unless the bead is saturated; then, it is yellow when cold. In the reducing flame, the bead is green when warm and colorless when cold unless saturated, when it is bottle-green when cold. Like- wise, both the non-saturated and saturated salt of phosphorus beads are yellow when warm and 30 BLOWPIPE ANALYSIS TABLE OF i 1 5: *j d g | ~ w 3 1 7- g i . > - ^ > 2! CQ * v ) P C we* Iron tP. c we* Note i ) F rr* ww* Molybdenum LF. we w*c* Note 2 . I.F. c we* Titanium R.F c we* d. OF we w* .,; Tungsten R.P. we w* < e. >.F c we* Uranium R.F. c ww* c* < OF c we* Note 3 I Vanadium R.F. we g. >.P w cc* w* Note 4 Chromium R.I'. we h. Copper O.F. R.F. ww* w CC* c c* Note 5 . OF we Cobalt R.F. we j. O.F. we Manganese R.F we k O F \v\v- cc* Nickel R.F. we Note 6 NOTE i. Strongly saturated bead is a dull bottle- or olive-green in the reducing flame when cold. NOTE 2. Strongly saturated bead is opaque brown in the reducing name. NOTE .3. Warm beads saturated and non-saturated, are both greenish yellow in the oxidizing flame. NOTE 4. Cold, non-saturated bead is yellowish green in the oxidizing NOTE s- Strongly saturated bead is opaque and dark brownish red in the reducing flame. METHODS Ob' TEST IXC, 31 BEAD TESTS Colorless. l c J PQ i "5 d i VI. a. Iron O.F. R.F. CC* C ivw* ww* c* Note 7 b. Titanium O.F. R.F. CC* c ww* ww* c* Note 8 c. Tungsten ! F R.F. we we w* w* C* Note 9 - ,1. Vanadium O.F. R.F we we Note to s Nickel O.F. R.F. CC* CC* ww* vw* f. OF w w*c : __ Chromium R.F. we : OF w c - .. Uranium R.F. we '' h. Molybdenum O.F. R.F c we* we N\,tc i i jCopper O.F. R.F \v\v- w CC* o c* Note 5 JCobalt O.F R.F we we k OF we Manganese R.F we NOTE 6. Saturated bead is gray and opaque in the reducing flame. NOTE 7. Warm bead is pale to deep yellowish green (depending on tin degree of saturation! in the reducing flame. NOTE 8. Cold, saturated bead is very pale violet m the reducing flame NOTE o Cold, saturated bead is greenish blue in the reducing flame. NOTE 10. The green reduction bead cannot be oxidized to yellow NOTE ii Cold, non-saturated bead is pale green in the reducing t . ng flame. 32 BLOWPIPE ANALYSIS colorless when cold in the oxidizing flame, while in the reducing flame the non-saturated salt of phos- phorous bead is pale yellowish green when warm and colorless when cold, and the saturated bead is deep yellowish green when warm and brown when cold. VI. TESTS WITH SALT OF PHOSPHORUS (SODIUM AMMONIUM PHOSPHATE OR MICROCOSMIC SALT) BEADS These tests are made in exactly the same manner as are those with borax beads and the same pre- cautions should be observed. The salt of phosphorus is, however, much more liquid than borax, especially when first heated, and drops off the wire very easily. It will be found necessary to build the bead up gradually by the addition of small particles picked up on the hot wire one after the other and to use smaller beads than with borax. If difficulty in retaining the bead is still ex- perienced, it will be found advisable to form a loop in the end of the wire by bending it around the point of a lead pencil. In any case, it is best while forming the bead to allow the flame to play upon the under side of the fusing mass, thus buoying it upward and decreasing its tendency to drop off. The salt of phosphorus tests are necessary for METHODS OF TESTING 33 the recognition of some of the elements, but in most cases they will be found useful merely to corroborate unsatisfactory borax bead tests, and they may often be omitted. The accompanying table indicates the colors of both salt of phosphorus and borax beads in both oxidizing and reducing flames. The abbreviations and use of the table have been explained in the discussion of the tests with borax beads. VII. FLAME TESTS When volatilized, certain substances impart more or less decided colors to a flame, and the recognition of these colors constitutes distinctive tests for such elements. The flames are best seen in a dark room or against a dark background, and even then it requires close application to perceive the very brief flashes of color which constitute the tests in many instances. Four different methods of making these tests may be used, and they should be applied in the order given, it being unnecessary, however, to seek further results after a determination has been made by any of the methods. If two elements, both of which yield characteristic flames, are present, one will usually so mask the other as to make the recognition of both impossible. The second, third, or fourth method should never be used upon a substance with a metallic 34 BLOWPIPE ANALYSIS lustre without a thorough preliminary roasting as As, Sb, Pb, and other easily reduced elements are apt to form fusible alloys with the platinum win or forceps and thus ruin them. Some elements yield their characteristic flarm colors best at a low heat while others requin the highest heat available, so it is always bes to use both low and high temperatures for eacl test. Some substances which ordinarily yield no flami tests may have some of their constituents converter into volatile, flame-tinting compounds by treatmen with some reagent, usually HCl or H 2 SO4. In fact it is a safe practice always to dampen the materia to be tested with HCl, not even trying a test withou the use of that acid. If no tinted flame results H 2 SO 4 should be tried. First Method. Place a fragment or some o the powdered substance upon charcoal, moistei with a few drops of concentrated HCl, and hea in the hottest portion of the blowpipe flame. Thi only result that need be sought and noted (th< others being more easily obtained, or the element: being more easily recognized, by other methods) i: the following: a, Azure-blue flame, with or without flashes, or a border, of encrald green Ci (If this test results favorably, care should be taken not to make the bead tests which could only METHODS OF TESTIXG 35 yield Cu, or to heat the material in the platinum forceps, since in either of these operations the Cu will alloy with the Pt and ruin it.) Second Method. .(This is applicable only to car- bonates. See IX.&.) Seize a sliver of considerable size in the. platinum forceps, moisten it with dilute HC1 (one part of acid to three or four parts of water), and hold the particle near the base of the flame of an alcohol lamp, the blowpipe flame not being used for this test. If the result is negative, repeat the operatipn, but use the hot tip of the alcohol flame instead of the base. In a few cases, cold or hot concentrated acid is. required and these should be tried as a last resort, but the dilute acid should be first tried, as there are several substances which will not give a good reaction with the strong acid. The splinter should be moistened by immersing it in the acid and holding it there until there is a vigorous effervescence (evolution of gas). Pure, fresh alcohol and acids should be used for these tests, as otherwise a yellow Na flame is apt to be very prominent and may mask .the flames yielded by Ba or Pb. If an alcohol lamp is not available, all of the tests described below may be obtained by using the method next given, but the results are more vivid and are easier obtained in the manner just described, if the substance tested is a carbonate. Possible results may be thus interpreted: 36 BLOWPIPE ANALYSIS b. Scarlet flame, lilac through blue glass Sr (A Li flame might easily be confused with that from Sr, but no known Li carbonate occurs in nature, so this test when obtained in the above described manner always indicates the presence of Sr.) c. Yellowish red flame, greenish through blue glass Ca (This is difficult to distinguish at first from the Sr flame, but is considerably less vivid and is inclined toward orange. It may be positively identi- fied by the fact that Ca salts give good tests no matter whether dipped in concentrated or dilute acid and dilute acid must be used to secure a good Sr flame.) d. Yellow flame Xa (This test is too delicate to be used with safety unless very intense and persistent. Specimens that have been handled will become sufficiently charged with Na from the fingers to give a good flame test.) e. Yellowish green flame, pale tint Ba (Masked by strong Na flame.) / Blue flame, pale tint Pb (Hot, concentrated acid is required for this test, and even then the color will appear for only an instant when the splinter is held in the tip of the flame.) Note. A vivid Cu flame may be obtained in this manner, but this should never be attempted, as the forceps will thereby be ruined. Third Method. Hold an extremely fine splinter METHODS OF TE^TIXG 37 (as slender as a very fine needle) in the platinum forceps, moisten it with a drop of HC1, and introduce it into the hottest part of the blowpipe flame. A flash or a continuous appearance of color may be imparted to the flame. If the result is negative or unsatisfactory, remoisten the splinter and reheat. If this fails, repeat the operation with H 2 SO 4 instead of HC1. Should the splinter decrepitate, try heating it very slowly, and, if it still flies to pieces, the fourth method must be used. Possible results may be thus interpreted: g. Carmine flame, violet through blue glass Li /;. Scarlet flame, lilac through blue glass Sr (The colors of the L5 and Sr flames are so similar that they are easily confused, but they may be readily distinguished by the fact that a substance that has been ignited and has given a Sr flame will turn moist red litmus paper blue when crushed and placed upon it. Li minerals show no effect of this kind.) i. Yellowish red flame, greenish through blue glass Ca (This is difficult to distinguish at first from the Sr or Li flames, but is considerably less vivid than either and is inclined toward orange.) ;'. Yellow flame Na (This test is too delicate to be used with safety unless very intense and persistent. Specimens that have been handled will become sufficiently charged with Na from the fingers to give a good flame test.) 38 nWU'Pll'E AXALYSIS k. Yellowish green flame, pale tint Ba (Masked by strong Na flame.) /. Bluish green flame, pale tint P (H 2 SO 4 must be used for this test and the result is not usually very satisfactory.) m. Bright green flame B (B minerals which do not give a flame test in this way should be powdered and mixed thoroughly with about three volumes of a mixture of equal parts of powdered acid potassium sulphate and calcium fluoride fluorite. This should be intro- duced into the flame as described in the fourth method.) . Blue flame, pale tint Pb o. Blue flame, pale tint Sb (The reducing flame must be used to obtain this result, which is neither very satisfactory nor determinative. Care should be taken not to test an Sb ore in this way, as it is apt to alloy with, and ruin, the platinum forceps.) p. Violet flame, violet through blue glass K (This is difficult to obtain in most cases and is entirely masked by a pale Na flame. The latter is, however, entirely absorbed by blue glass, which transmits the K flame as of lilac or violet color, depending upon the shade of the glass.) Note. A vivid Cu flame may be obtained in this manner, but this should never be attempted, as the forceps will thereby be ruined. Fourth Method. Powder the material to be tested very fine, pick up a little of this powder upon METHODS OF TESTING 39 a, flattened platinum wire moistened with HC1, and introduce the powder-coated wire into the hottest part of the blowpipe flame. Momentary flashes or continuous appearances of color may be imparted to the flame, which are to be interpreted as under the third method. If the results are nega- tive, repeat the operation, using H2SO4 instead of HC1. This method is not usually very satisfactory and should not be used unless it is impossible to obtain a splinter fine enough to be tested by the third method. Minerals which decrepitate badly, which are very soft, or which occur as a powder must, of course, be tested by this last method. VIII. COBALT NITRATE COLORATION TESTS To make these tests, hold a small splinter of the substance to be tested in the platinum forceps and heat it in the blowpipe flame to the highest possible temperature. Then examine it with a lens; if it shows any signs of fusion, this test cannot be applied. If non-fusible, moisten it with cobalt nitrate and ignite strongly in the hottest part of the blowpipe flame. It will first turn black but after prolonged heating may assume a characteristic tint. If a splinter of the substance cannot be obtained, it should be powdered and the test conducted upon a flat cake of the powder upon charcoal. Longer 40 BLOWPIPE AXALYSIS heating is required by this method, however, and the results are not apt to be as satisfactory. This test can be applied only to non-fusible, white or faintly tinted minerals, or those which become white or faintly tinted upon ignition. Possible results may be thus interpreted: a. Plue coloration Al or Zn silicate (Al minerals and Zn silicate give identical results by this test. If Zn has been obtained by tests I.e., or II. a., it is impossible to test for Al in this way. If Zn is not present, this test may be inter- preted as indicating the presence of Al. Occa- sionally a little green forms with the blue on Zn silicates, which never happens in the case of Al min- erals.) b. Green coloration, dark Sb c. Green coloration, bright tint, best seen when cold Zn d. Pinkish or flesh-tint coloration Mg IX. TESTS WITH ACIDS These are really purely chemical and should not be included under blowpipe analysis, but two are so simple and useful that they are given below. a. The finely powdered material, when boiled almost to dryness in concentrated nitric acid, yields a gelatinous mass a silicate b. The powdered material effervesces vigorously METHODS OF TEST1XG 41 when placed in a test-tube containing some condition of hydrochloric acid a carbonate (In some cases the tests appear in cold, dilute acid, while, in other instances, hot dilute, cold con- centrated, or hot concentrated may be required. It is best to experiment with the dilute acid first, and then, if results are negative, to increase the temperature until all conditions of acid have been tried. It is not always necessary to powder the material to be tested, but this is sometimes required and never does any harm. Care should be taken not to confuse effervescence (escape of CO 2 ) with boiling (escape of steam) when boiling acid is used. Some sulphides may effervesce in hydrochloric acid, but these may be distinguished from carbon- ates by the fact that they yield a gas (H 2 S) that smells like bad eggs.) CHAPTER III NK I <>R OrALlTATIYK BLOWPJPK ANALYSIS BLOWPIPE analysis is ordinarily used for the pur- pose of ascertaining what elements an unknown substance contains, this process being known in chemistry as qualitative analysis. It is not possible, excepting in a few cases and by the application of very refined methods not here discussed, to deter- mine how much of an element is present to make a quantitative analysis of the substance, but, if the elements present are known, it is usually possible to determine the nature of the substance by applying the principles set' forth in Chapter IV. Where the nature of a mineral has thus been determined, it is comparatively easy to compute the percentage com- position with considerable accuracy in many cases, by applying the principles presented in Chapter VI, A tabulation of the principal elements present in many common minerals are given in Chap ter V. Even when the name and nature of the mineral cannot be ascertained by blowpipe methods, the ability to ascertain the commercially important elements that it contains is often of the 42 QUALITATIVE BLOWPIPE ANALYSIS 43 greatest value, since it is then possible to decide whether it is worth while to procure a chemical analysis or an assay of the substance. The following scheme has been devised as a guide for making a complete qualitative analysis of an unknown substance with the greatest economy of time and labor. It should not be expected that every mineral containing As, for instance, will yield every test for As mentioned in Chapter II or in the following outline, but in most cases the mineral will give one or more of the tests there given. It is poor practice to assume that a mineral contains a certain element and then test for that element, repeating the operation for other elements. A far better plan is to follow the outline rigidly and to draw conclusions from the results secured. This saves time and makes it impossible to forget to try tests. If it is suspected that Hg is present in a substance, it should be tested only in the closed tube (see III.6.)) as the vapors are very poisonous. OUTLINE A. Powder material very fine and place upon char- coal, pressing out with a knife-blade into a flat cake. Moisten with water if necessary to keep the charge from flying off the charcoal, i. Test for As, Sb, Sb with As, Mo, Te, As with 44 BLOWPIPE AX.lLVSfS S, Pb, Bi, Cd, Sc, Ag with Pb, and S. (Seel.) 2. Test for Fe. (See I. p.) Separate the residue from the above tests into two portions and save one of these for a later test. On the portion still remaining on the charcoal make: 3. Test for Zn and Sn. (See I.e. and I.g.) 4. Test for Cu on residue from A-3- (See VII. a.) 5. Test for Al, Mg, Zn, Sb, and Zn silicate on residue from A.4. (See VIII.) (This test can be made only upon light colored, infusible material, and need not be tried if Zn has already been found.) B. If A.4. gave no Cu flame (if Cu is present it is useless to make the following tests) make borax and salt of phosphorus bead tests for the ele- ments named below, using the residue saved from A. 2. i. Test for Fe, Mo, Ti, W, U, V, Cr, Cu, Co, Mn, and Ni. (See V. and VI.) C. In case A.I. gave a result that might be inter- preted as indicating either Pb or Bi, use the bismuth flux test to distinguish them, i. Test for Bi on some of the original material, using bismuth flux. (See I./.) D. If A.4. gave no Cu flame (if Cu is present it is useless to make the following tests), hold a piece of the original material as large as a tooth- QUALITATIVE BLOWPIPE ANALYSIS 45 pick or match in the platinum forceps and make the flame tests as described under VII., Second Method. 1. Test for Sr, Ca, Na, Ba, and Pb carbonates. (See VII., Second Method.) If no satisfactory results are obtained from D.I., make the flame tests as described under VII., Third Method. 2. Test for Li, Sr, Ca, Na, Ba, P, B, Pb, Sb, and K. (See VII. , Third Method.) If no satisfactory results are obtained from D.2., make the flame tests as described under VII. , Fourth Method. 3. Test for Li, Sr, Ca, Na, Ba, P, B, Pb, Sb, and K. (See VII., Third Method.) E. On some of the original material, powdered, make the closed tube tests without flux. 1. Test for H 2 O, Hg, Te, Cd, As, Sb, S, As with S, Sb with S, Hg with S, and Se. (See IH.a. to/.) On some of the original material, powdered, make the closed, tube tests with flux, provided E.I. has not yielded determinative results. 2. Test for H 2 O, Hg, Te, Cd, As, and Sb. (See Ill.m. to r.) On some of the original material, powdered, make the closed tube test with acid potassium sulphate. 46 BLOWPIPE ANALYSIS 3. Test for F. (See lll.s.) F. On some of the original material, powdered, make the open tube tests. i. Test for H 2 O, S, As, Sb, Sb with S, Pb with S, Te, Bi with S, Mo, As with S, and Se. (See IV.) Note. It is always well to make tests E. and F. even when A. has given determinative results, as several of the elements determined by means of tests E. and F. may fail to show in test A. It is a good practice to corroborate results obtained by test A. by means of tests E and F. G. On some of the original material, powdered, make the tests on charcoal with flux. 1. Test for Zn, Ag with Pb, Pb, Bi, Ag, Sn, Au, Cu, and Fe, Co, or Ni. (See II.) On the residue from G.I., make the silver test for S, Te, or Se, provided these elements, or one of them, have not already been detected by other tests. 2. Test for S, Te, or Se. ' (See II.;.) H, On some of the original material, powdered, make the tests with acids in test-tubes. 1. Test for a silicate with nitric acid. (See IX.c.) 2. Test for a carbonate with hydrochloric acid. (SeeIX.6.) CHAPTER IV IXDKX TO ALL OF THE TESTS YIELDED BY THE VARIOUS ELEMENTS IT is the purpose of this index to furnish a complete list of all the blowpipe tests for any element dis- cussed in the preceding pages. It will be found useful where the interest is concentrated upon one or two elements to the exclusion of all others, but should not be used in making a complete qualitative blow- pipe analysis of a substance. It should not be expected, that any mineral will necessarily yield all of the tests for each of the constituents. The references are to the tests described in Chapter II, and a page index of these tests is here given : PAQB I. Treatment on Charcoal without Flux . . i o II. Treatment on Charcoal with Flux 15 III. Tests in Closed Tubes 19 IV. Tests in Open Tubes 23 V. Tests with Borax Beads 25 VI. Tests with Salt of Phosphorus Beads. . 32 VII. Flame Tests 33 VIII. Cobalt Nitrate Coloration Tests 39 IX. Tests with Acids 40 47 48 BLOWPIPE ANALYSIS Aluminum: VIII.,a. Antimony: l.b., I.e., Hl.g., III./., IILr., IV.d., IVe., VII.o., and VIII.6. Arsenic: I. a., I.e., I.h., I.k., Ill.e., lll.i., lll.q., IV.c., IV.;., and IYJ. Barium: Vll.e., and VII.*. Bismuth: I.;., II.d., and IV.A. Boron: Vll.m. Cadmium: I/., II W., and III.^. Calcium: VII.c., and VII./. Chromium: V.g., and VL/. Cobalt: I.p., II.*., V.i., and VI. j. Copper: ll.h., V.h., VI.*., and Vll.a. Fluorine: III.s. Gold: II.g. Iron: !./>., Il.f,. V.a., and VLa. Lead: I.i., !.., II &, II.c., IV./., VII./., and Vll.n. Lithium: VII.^. Magnesium: VIII. d. Manganese: V.;., and VL*. Mercury: III.&., III.*., and III.w. Molybdenum: l.d. t IV.*., V.b., and VI.h. Nickel: I.p., II.*., V.*., and VI.e. Phosphorus: VIIJ. Potassium: VII.p. Selenium: I.m., II.;.,- III./., and IV.*. Silver: !.., H.&., and Il.e. Sodium: Vll.d., and VII./. TESTS YIELDED BY VARIOUS ELEMENTS 49 Strontium: VII.6., and VILA. Sulphur: LA., I.e., II./., III.A., III.*., III./., III.*., IV.6., IV.e., IV./, IV.A., and IV./. Tellurium: I./., II.;., IILc., III./., III.o., and Tin: I*., and II./. Titanium: V.c., and VI.6. Tungsten: V.d., and VI.c. Uranium: V.e., and Vl.g. Vanadium: V./., and Vl.d. Zinc: I.e., ILa., VIILa., and VIII.c. Water: IILa., Ill.m., and IV.a. A silicate: IX.a. A carbonate: IX.6. CHAPTER V THE DETERMINATION OI MINERALS BY MEANS OF THE BLOWPIPE WHILE the determination of the constituent ele- ments of a mineral is the usual aim of a blowpipe analysis, it is often desirable to be able to assign the correct mineralogical name to the substance, since, when this can be done, it is frequently possible to determine its percentage composition with con- siderable accuracy. It is not, unfortunately, possible in many cases to determine a mineral by blowpipe tests alone; these must be considered in connection with the physical characteristics before a reliable decision as to the correct name can be safely made. There are, however, a considerable number of minerals with unique groups of constituents which may be determined by blowpipe analyses, and it is hoped that the following table will prove useful in this respect. It includes most of the important ores and some of lesser importance, as well as a number of gangue minerals, but some very important ores are omitted as well as a great number of common minerals for the reason that blowpipe tests arc little or no aid in their recognition. In a large ,50 DETERMINATION OF MINERALS 51 number of cases two or more minerals on this table yield tests for identically the same elements. Such substances can be readily distinguished by their appearance or by simple physical tests. For this purpose almost any book on mineralogy will answer, but the author naturally prefers his own work, A Pocket Handbook of Minerals, published by John Wiley & Sons, New York, which places all the emphasis upon the physical distinctions. In the following table the chemical formula is placed in parentheses after the name of each min- eral. By applying the principles presented in Chapter VI it should be a comparatively simple matter to^ compute the percentage of any or all elements present in any mineral of fixed composition. The letters to the left of each name are the symbols of the elements that may be found by means of the blowpipe; in comparatively few cases do they con- stitute all the elements present in the mineral before which they stand, but the remainder fail to give satisfactory tests with the blowpipe. The name of a mineral is repeated under each element for which it yields blowpipe tests. Water (H 2 O) is treated as an element. Aluminum. Al Corundum (A1 2 O 3 ) Al, Li Spodumene (LiAlSi 2 O G ). Al, P, H 2 O Turquois ( A1PO.,.A1(OH) 3 +H 2 O + Cu). 52 BLOWPIPE ANALYSIS ^ Al, K Orthoclase (KAlSiaO 8 ). Al,S,H 2 0-Alunite(K 2 SO 4 . 3 Al 2 O 3 .3SO 3 .6H 2 O). Al, H 2 O Bauxite (A1 2 O 3 + 2H 2 O). Al, H 2 O Kaolin (Al 2 Si 2 O 7 + 2H 2 O). Antimony. Sb Native Antimony (Sb). Sb Cervantite (Sb 2 O 4 ). Sb, As Allemontite (SbAs). ^ Sb, Cu, S Tetrahedrite (Cu 8 Sb 2 S 7 ). Sb, Pb, S Jamesonite (Pb 2 Sb 2 S 5 ). Sb, Ag, S Pyrargyrite (AggSbSa). Sb, Ag, S Stephanite (Ag 5 SbS 4 ). u Sb, S Stibnite (Sb 2 S 3 ). Arsenic. As Native Arsenic (As). As, Sb Allemontite (AsSb). As, Co Smaltite ((Co,Ni) As 2 ). i- As, Co, S Cobaltite (CoAsS). As, Cu, S Tennantite (Cu 8 As 2 S 7 ). As, Cu, S Enargite (Cu 3 AsS 4 ). As, Cu, H 2 O Olivenite (Cu 4 As 2 O 9 +H 2 O). As, Cu, H 2 O Conichalcite ((Cu,Ca) 4 As 2 O 9 -f 3 / 2 H 2 0). As, Fe Lollingite (FeAs 2 ). As, Fe, S Arsenopyrite (FeAsS). As, Ni Niccolite (NiAs). As, Pb Mimetite (PbCl 2 .3Pb 3 As 2 O 8 .). As, Ag, S Proustite (Ag-jAsSg). DETERMINATION OF MINERALS 53 As, S Realgar (As 2 S 2 ). As, S Orpiment (As 2 S 3 ). Barium. Ba Witherite (BaCO 3 ). Ba, S Barite (BaSO 4 ). Bismuth. Bi Native Bismuth (Bi). Bi Bismite (Bi 2 O 3 ). Bi, S Bismuthinite (Bi 2 S 3 ). Bi, Te Tetradymite (TeBi). Bi, H 2 O Bismutite (Bi 2 CO 5 + H 2 O). Boron. B Boracite (Mg 7 Cl 2 B 1G O3o). B, Na, H 2 O Borax (Na 2 B 4 O 7 4-ioH 2 O). B, H 2 O Colemanite (Ca 2 B 6 Oii+5H 2 O). Cadmium. Cd, S Greenockite (CdS). Calcium. Ca Calcite (CaCO 3 ). Ca, F Fluorite (CaF 2 ). Ca, Mg Dolomite ((Ca, Mg) CO 3 ). Ca, P Apatite (Ca (Cl, F)2.3Ca 3 P 2 O 8 ). Ca, S Anhydrite (CaSO 4 ). Ca, S, H 2 O Gypsum (CaSO 4 + 2H 2 O). Chromium. Cr, Fe Chromite (FeCr 2 O 4 ). Cr, Pb Crocoite (PbCrO 4 ). 54 BLOW PIPI-: ANALYSIS Cobalt. Co, As Smaltite ((Co, Ni) As 2 ). Co, As, S Cobaltite (CoAsS). Copper Cu Native Copper (Cu). Cu Cuprite (Cu 2 O). Cu Tenorite (CuO). Cu Atacamite (CuCl 2 .3Cu(OH) 2 ). Cu, Sb, S Tetrahedrite (Cu 8 Sb2S 7 ). Cu, As, S Tennantite (Cu8As 2 S 7 ). Cu, As, S Enargite (Cu 3 AsS 4 ). Cu, As, H 2 O Olivenite (Cu 4 As 2 O 9 +H 2 O). Cu, As, H 2 O Conichalcite ((Cu, Ca) 4 As 2 O 9 + 3/2H 2 0). Cu, Fe, S Bornite (Cu 5 FeS 4 ). Cu, Fe,S Chalcopyrite (CuFeS 2 ). Cu, S Chalcocite (Cu 2 S). Cu, S Covellite (CuS). Cu, S, H 2 O Chalcanthite (CuSO 4 + 5H L >O). Cu, H 2 O Malachite (Cu 2 CO 4 + H 2 O). Cu,H 2 O Azurite (Cu 3 C 2 O 7 + H 2 O). Cu, H 2 O Chrysocolla (CuSiO 3 + 2H 2 O). Fluorine. F, Ca Fluorite (CaF 2 ). F, Na Cryolite (Na 3 AlF 6 ). Gold. An Native Gold (Au,. Au, Te Calaverite (AuTe 2 ). DETERMINATION OF MINERALS Iron. * Fe Hematite (Fe 2 O 3 ). *- Fe Magnetite (Fe 3 O 4 ). Fe Siderite (FeCO 3 ). Fc, As Lollingite (FeAs 2 ). Fe, As, S Arsenopyrite (FeAsS). Fe, Cr Chromite (FeCr 2 O 4 ). . Fe, Mn, Zn Franklinite ((Fe, Zn, Mn) 3 O 4 ). Fe, P, H 2 O Vivianite (Fe 3 P 2 O 8 -f-8H 2 O). Fe, S Pyrrhotite (Fe n S n + I ). Fe, S Pyrite (FeS 2 ). Fe, Ti Ilmenite (FeTiO 3 ). Fe, H 2 O Limonite (2Fe 2 O 3 + 3H 2 O). Lead. Pb Cerussite (PbCO 3 ). Pb, Sb, S Jamesonite (Pb2Sb 2 S 5 ). Pb, As Mimetite (PbCl 2 .3Pb 3 As 2 O 8 .). Pb, Cr Crocoite (PbCrO 4 ). ^ Pb, Mo Wulfenite (PbMoO 4 ). Pb, P Pyromorphite (PbCl 2 .3Pb 3 P 2 O 8 ). Pb, S Galenite (PbS). Pb, S Anglesite (PbSO 4 ). Pb, V Vanadinite (PbCl 2 . 3 Pb 3 V 2 O 8 ). Pb, V, etc. Uraninite (?). Lithium. Li, Al Spodumene (LiAlSi 2 O 6 ). Magnesium Mg Magnesite (MgCO 3 ). 56 BLOWPIPE AXALYSIS Mg, Ca Dolomite ((Mg, Ca)CO 3 ). Mg, H 2 Talc (MgaSi.On+HoO). Manganese. Mn Pyrolusite (MnO 2 ). Mn Rhodochrosite (MnCO 3 ). Mn Rhodonite (MnSiO 3 ). Mn, Fe, Zn Franklinite ( (Mn, Fe, Zn) 3 O 4 ). Mn, S Alabandite (MnS). Mn, H 2 O Manganite (Mn 2 O 3 + H 2 O). Mn, H 2 O Psilomelane (MnO 2 + 2H 2 O). Mercury. Hg Native Mercury (Hg). Hg, S Cinnabar (HgS). Molybdenum. Mo Molybdite (MoO 3 ). Mo, Pb Wulfenite (PbMoO 4 ). Mo, S Molybdenite (MoS 2 ). Nickel. Ni, As Niccolite (NiAs). Ni, S Millerite (NiS). Ni, H 2 Garnierite (H 2 (Ni, Mg)SiO 4 + H 2 O). Phosphorus. P, Al, H 2 O Turquois (A1PO 4 .A1(OH) 3 + H 2 O + Cu). P, Ca Apatite (Ca(Cl, F) 2 . 3 Ca 3 P 2 O 8 ). P, Fe, H 2 O Vivianite (Fe 3 P 2 O 8 + 8H 2 O). P, Pb Pyromorphite (PbCl 2 .3Pb 3 P 2 O 8 ). DETERMINAT1OX OF MINERALS 57 Potassium. K Sylvite (KC1). K, Al Orthoclase (KAlSi 3 O 8 ). Selenium. Se, Pb Clausthalite (PbSe). Silver. Ag Native Silver (Ag). Ag Cerargyrite (AgCl). Ag, Sb, S Pyrargyrite (AgsSbS 3 ). Ag, Sb, S Stephanite (Ag 5 SbS 4 ). Ag, As, S Proustite (Ag 3 AsS 3 ). Ag, Te Petzite ((Ag, Au) 2 Te). Ag, Te Sylvanite ( (Ag, Au)Te 2 ). Ag, S Argentite (AgzS). Ag, Te Hessite (Ag^e). Sodium Na Halite (NaCl). Na, B, H 2 O Borax (Na 2 B 4 O 7 + ioH 2 O). Na, F Cryolite (Na 3 AlF 6 ). Na, S Thenardite (Na 2 SO 4 ). Na, H 2 O Natron (Na 2 CO 3 + ioH 2 O). Na, H 2 OTrona (Na 2 CO 3 .HNaCO 3 +2H 2 O). Strontium Sr Strontianite (SrCO 3 ). Sr, S Celestite (SrSO 4 ). 58 BLOWPIPE ANALYSIS Sulphur. S Native Sulphur (S). S,Al,H 2 O-Alunite(K 2 S0 4 . 3 Al 2 3 .3S0 3 .6H 2 O). ' S, Sb Stibnite (Sb 2 S 3 ). - S, Sb, Cu Tetrahedrite (Cu 8 Sb>S 7 ). S, Sb, Pb Jamesonite (Pb 2 Sb 2 S.-,). S, Sb, Ag Pyrargyritc (AgsSbS 3 ). S, As Realgar (As 2 S 2 ). t-S, As Orpiment (As 2 S 3 ). S, As, Cu Tennantite (Cu 8 As 2 S 7 ). S, As, Cu Enargite (Cu 3 AsS 4 ). S, As, Fe Arsenopyrite (FeAsS). S, As, Ag Proustite (AgsAsSs). -S,Ba Barite (BaSO 4 ). S, Bi Bismuthinite (Bi 2 S 3 ). S, Cd Greenockite (CdS). S, Ca Anhydrite (CaSO 4 ). S, Ca, H 2 O Gypsum (CaSO 4 + 2H 2 O). S, Cu Chalcocite (Cu 2 S). S, Cu Covellite (CuS). S, Cu, Fe Bornite (Cu 5 FeS 4 ). - S, Cu, Fe Chalcopyrite (CuFeS 2 ). S, Cu, H 2 O Chalcanthite ^S, Fe Pyrrhotite (Fe n S n +i). -S, Fe Pyrite (FeS 2 ). . S, Pb Galenite (PbS). S, Pb Anglesite (PbSO 4 ). S, Mn Alabandite (MnS). -S, Mo Molybdenite (MoS 2 ). DETERMINATION OF MINERALS 59 S,Ni Millerite(NiS). S, Ag Argentite (A&S). S, Na Thenardite (Na 2 SO 4 ). *S, Sr Celestite (SrSO 4 ). S, Zn Sphalerite (ZnS). Tellurium. Te Native Tellurium (Te). Te, Bi Tetradymite (BiTe). Te, An Gala verite (AuTe 2 ). Te, Ag Petzite ((Au, Ag) 2 Te). Te, Ag Sylvanite ((Au, Ag)Te 2 ). Tin. - Sn Cassiterite (SnO 2 ). Titanium. - Ti Rutile (TiO 2 ). Ti Titanite (CaTiSiO 6 ). Ti, Fe Ilmenite (TeTiO 3 ). Tungsten. W Scheelite (CaWO 4 ). Uranium. I", Pb, etc. Uraninite (?). Vanadium. V. Pb Yanadinite (Pb Zinc. Zn Zincite (ZnO). Zn Smithsonite (ZnCO 3 ). 60 BLOWPIPE AXALVSIS Zn Willemite (Zn 2 SiO 4 ). Zn, Fe, Mn Franklinite ((Zn, Fe, Mn) 3 O 4 ). Zn, S Sphalerite (ZnS). Zn, H 2 O Hydrozincite foZnCOg + 2H 2 O). Zn, H 2 O Calamine (Zn 2 SiO 4 + H 2 O). Water. H 2 O, Al Bauxite (A1 2 O 3 + 2H 2 O). H 2 0, Al Kaolin (Al 2 Si 2 O 7 + 2 H 2 O). H 2 O,A1,P Turquois(AlPO 4 .Al(OH) 3 +H 2 O + Cu). H 2 0,Al,S-Alunite(K 2 SO 4 .3Al 2 3 .3S0 3 .6H 2 0). H 2 O, As, Cu Olivenite (Cu 4 As 2 6 9 + H 2 O). H 2 O, As, Cu Conichalcite ((Cu, Ca) 4 As 2 O 9 + 3/2H 2 0). H 2 O, Bi Bismutite (Bi 2 CO 5 -f H 2 O). H 2 O, B Colemanite (Ca 2 BOiiH-5H 2 O). H 2 O, B, Na Borax (Na 2 B 4 O 7 + ioH 2 O). H 2 O, Ca, S Gypsum (CaSO 4 + 2H 2 O). " H 2 O, Cu Malachite (Cu 2 CO 4 + H 2 O). H 2 O, Cu Azurite (Cu 3 C 2 O 7 + H 2 O). H 2 O, Cu Crysocolla (CuSiO 3 + 2H 2 O). H 2 O, Fe Limonite (2Fe 2 O 3 +3H 2 O). H 2 O, Fe, P Vmanite (Fe 3 P 2 O 8 +8H 2 O). 1 H 2 O, Mg Talc (Mg3Si 4 Oii+H 2 O). H 2 O, Mn Manganite (Mn 2 O 3 + H 2 O). H 2 O, Mn Psilomelane (MnO 2 + 2H 2 O). H 2 O, Ni Garnierite (H 2 (Ni, Mg)SiO 4 + H 2 O). H 2 O, Na Natron (Na 2 CO 3 + ioH 2 O). H 2 O, Na Trona (Na 2 CO 3 .HXaCO 3 -f 2H 2 O). DETERMINATION OF MINERALS 61 H 2 O, Zn Hydrozincite H 2 O, Zn Calamine (Zn 2 SiO 4 + H 2 O). Silicates. The two mentioned below are the only ones in the above list which will give the test for a silicate described previously. Willemite (Zn 2 SiO 4 ). Calamine (Zn 2 SiO 4 + H 2 O). Carbonates. Ba Witherite (BaCO 3 ). Bi Bismutite (Bi 2 CO 5 + H 2 O) . - Ca Calcite (CaCO 3 ). Ca, Mg Dolomite ((Ca, Mg)CO 3 ). Cu, H 2 O Malachite (Cu 2 CO 4 + H 2 O). Cu, H 2 O Azurite (Cu 3 C 2 O 7 + H 2 O). Fe Siderite (FeCO 3 ). Pb Cerussite (PbCO 3 ). Mg Magnesite (MgCO 3 ). Mn Rhodochrosite (MnCO 3 ). Na, H 2 O Natron (Na 2 CO 3 + ioH 2 O). Na, H 2 O Trona (Na 2 CO 3 .HNaCO 3 +2H 2 O). Sr Strontianite (SrCO 3 ). Zn Smithsonite (ZnCO 3 ). Zn, H 2 O Hydroeincite CHAPTER VI THE ELEMENTARY PRINCIPLES OF CHEMISTRY 'ERPRETAT SYMBOLS Elements. Every body in nature is composed of one of more constituent substances called elements. Sometimes, as in the case of the metals gold, silver, and copper, there is only one substance; it is itself an element. In other cases there are two or more elemental constituents present in the body, which by proper manipulation may be broken up or resolved into its elements. An element, is then, something that has resisted all attempts to subdivide it into other substances. It follows, necessarily, that an element cannot be formed by a union of other substances. Each element differs more or less from all others in appearance, properties, and uses. Some are gases, some are opaque and reflect light from the surface are metals, and some are transparent or translucent are non-metals. The distinction be- tween metals and non-metals is, however, not sharply marked, since there are elements with inter- 62 ELEMENTARY PRINCIPLES OF CHEMISTRY 63 mediate properties. A full list of all known elements is given in the table at the end of this chapter. It has happened occasionally that a substance supposed to be an element has been found to be composed of two or more elements, and this will probably occur in the future, but chemists feel practically certain of the elementary condition of all the commoner elements. They know now that the Alchemists' search for a method of making gold was foredoomed to failure. Chemical Compounds. Elements have the prop- erty of uniting under certain conditions to form new substances, differing in nature from any of the constituent elements. The results of such unions are not merely mechanical mixtures of the elements in which each component can be identified under the high-power microscope, but are homogeneous substances of definite properties, which will often fail to respond to tests yielded by their constituent elements. Such combinations of two or more elements are called chemical compounds. Thus, the common chemical compound water is composed of one gas, hydrogen, which burns in the air, and another, oxygen, which is essential for respiration, properties quite foreign to water. Most natural bodies are either chemical compounds or mixtures of them. Other peculiarities possessed by them will be mentioned later. Alloys. Alloys are rather indefinite compounds 64 BLOWPIPE AXALYSIS of metals whose natures are not thoroughly under- stood. Atoms. Atoms are the smallest particles into which it is believed an element may be divided and still retain all its distinguishing properties. Although not infinitely small, they are far too minute to be seen with the microscope, yet there are abundant more or less indirect proofs of the correctness of the atomic theory. That atoms are themselves subdivisible is now admitted, but these lesser par- ticles reveal the characteristic properties of entirely different elements from those which they formed before disintegration, and are produced only under very unusual conditions, probably never, or very rarely, duplicated in chemical operations. According to the atomic theory, the atoms of any element have the same weight and size and are identically alike, while the atoms of different ele- ments have different weights and sizes, and further differ to the same extent as do the elements themselves. Molecules. Molecules are the smallest particles into which it is believed a chemical compound may be divided and still remain the same chemical compound. They must consist, evidently, of at least two, and often several, atoms. The same word (molecule) is also applied to the smallest volumes of a gas, even though it be an element instead of a compound, since it appears certain that the smallest ELEMENTARY PRINCIPLES OF CHEMISTRY 65 particles of gases always consist of at least two atoms. With certain modifications that it is not necessary to discuss, it may be stated that the number of atoms present in a molecule of a given chemical compound is always the same, and that the different atoms forming a molecule of a certain chemical compound are always present in a fixed proportion. Thus, a molecule of water always contains two atoms of hydrogen and one atom of oxygen. Symbols. For convenience, the elements are represented by the initial letter, either alone or with an added letter, of their Latin or Greek names, which are in many cases very similar to their English names. These letters are called the symbols of the elements. Formulae. The formula of a chemical compound is written by placing the symbols of its component elements in a line, and, if more than one atom of any of these is present in the molecule of the com- pound, the number of such atoms is indicated by subscripts written after the symbols of the elements thus affected. Thus, the formula of water is H^O, indicating that the molecule of water contains two atoms of H combined with one atom of O. This formula is read h-two-o. It is sometimes possible to group the atoms in the formula of a complex substance in such a fashion as to form two or more groups of molecules, indicat- 66 BLOWPIPE ANALYSIS ing that the substance may be formed not only by a union of atoms but also by a combination of molecules. Such formulae may be written with a period separating the constituent molecules. Thus, CaCOs (read c-a-c-o-three) is the symbol of calcite, of which marble is a variety, and this formula may be written CaO.CO 2) indicating that the material is formed by the union of one molecule of lime (CaO) and one of carbonic acid gas (CO2). When it is possible to break up a formula into molecules in this way, it is often found that more than one of a certain constituent molecule is present in substance. Thus, the ordinary formula of ortho- clase feldspar is KAlSi 3 O 8 , but, after multiplying each atom by two, this is found to consist of one molecule of potassium oxide (K 2 O), one of alumina (A1 2 O 3 ), and six of silica (SiO 2 ), and may therefore be written K 2 O.Al 2 O3.6SiO2. The order in which the different molecules are written is of no great importance; the above formula might with equal correctness be written 6SiO 2 .K 2 O.Al 2 O3, although this is not the customary order. It should be noticed that a figure prefixed to a molecule, as in the case of the 6 in the above formula, applies only to the molecule to which it is prefixed. Sometimes formulas like the following (the formula of emerald) are used: Be 3 Al 2 (SiO 3 )6. This is read b-e-three-a-1-two - parenthesis-s - i-o - three - taken - six- times. Both the Si and the O in the parenthesis are ELEMENTARY PRINCIPLES OF CHEMISTRY 67 affected by the subscript 6 and might be written Si 6 Oi 8 , but it is sometimes desirable to group ele- ments in parentheses in this way. Groups like this are not molecules since they do not occur as known chemical compounds. A different use of the parenthesis is seen in the case of those compounds in which the relative pro- portions of certain compounds are apt to vary apparently a modification or violation of a previously expressed law. Thus, a common constituent of limestone is a mineral called dolomite, whose formula is (Mg,Ca)CO 3 . Here the comma between the Mg and Ca indicates that the relative proportion of Mg and Ca is not fixed; there may be a nearly or quite equal number of atoms of both present, or either may predominate to a small or great extent over the other. In an instance like this the element first written in the parenthesis is apt to be the more plentiful. Sometimes it is more con- venient (as when the horizontal space is limited) to write the variable elements in such formulae in a vertical column without using the comma, in this manner: ( \ Atomic weights. The atomic weight of an element is the relative weight of an atom of the element compared with the weight of an atom of H, which is taken as unity, it being the lightest known element. Thus, an atom of Fe is fifty-six 68 BLOIVPII'E AXAI.YSIS times as heavy as an atom of H, so the atomic weight of Fe is 56. A presentation of the methods by which the atomic weights of the various elements are determined is not necessary, but these atomic weights have a practical use which is important. This may be illustrated as follows: Since pure water is composed entirely of molecules having the formula H 2 O, if wt know the relative weights of the H and O atoms, it should be a simple matter to calculate the proportions by weight of H and O in the molecule, and thus to determine the proportion by weight of these elements in any amount of the substance. There being two atoms of H present in the molecule, each of which weighs one unit (atomic weight of H is i), and one atom of O, which weighs sixteen units (atomic weight of O is 16), the whole molecule must weigh 2 + 16=18. units. It is plain that the H must constitute 2 /i 8 , or 1 /g, and the O form 16 /i8> or 8 / 9 of the whole molecule. It fol- lows that pure water in any amount is 1 / 9 H and 8 / 9 o. In this way it is always possible to calculate the relative proportions of the different elements in a substance whose formula is known, provided no elements involved occur in variable quantities, indicated by placing them, separated by commas, in parentheses, or in vertical columns in parentheses, as previously explained. The atomic weights of ELEMENTARY PRINCIPLES OF CHEMISTRY 69 all the elements are given in the table at the end of this chapter. Suppose, for illustration, it be required to find how many pounds of each of the component elements there are in 100 pounds of pure marble, with the formula CaCO 3 . Let the abbreviation A.W. mean atomic weight, then A.W. Ca=40. Total weight of the one Ca atom = 40 H units. A.W. C=i2. Total weight of the one C atom = 12 H units. A.W. O = i6. Total weight of the three O atoms =48 (3X16) H units. Total weight of the molecule = 100 H units. Ca present is 4 %oo of whole = 40% = 40 pounds. C present is 12 /ioo of whole =12% =12 pounds. O present is 48 /ioo of whole = 48% = 48 pounds. As a still more complex case, let it be required to ascertain the amount of Zn and H 2 O in 100 pounds of hydrozincite, with the formula 3ZnCO3 + 2H2O. A.W. Zn = 65-4. Number of atoms of Zn = 3> Weight of three Zn atoms (3X65.4) = 196.2. A.W. C=i2. "Number of atoms of = 3. Weight of three C atoms (3X12)= 36. A.W. O = 1 6. Number of atoms of O = 1 1. Weight of eleven O atoms (nXi6) = i76. A.W. H=i. Number of atoms of H = 4. Weight of four H atoms (4X1) =4. 70 BLOWPIPE AXALYSIS Weight of molecule (in H units) -=412.2. Zn present is 196-2 / 412 .2 of whole = 47. 6% = 47. 6 pounds. H 2 O present is 36 4V2 .2 of whole = 8. 7% = 8. 7 pounds. Molecular Weights. The molecular weight of a molecule or chemical compound is the sum of the atomic weights of the elements forming the molecule or compound, taking the atomic weight of each element as many times as there are atoms of that element present. Acids. Acids are substances that impart a red coloration to blue litmus paper. Two kinds are recognized: the halogen acids, compounds of H and one of the so-called halogen elements, Cl, F, Br, and I, and the oxygen acids, compounds of O and H with some other element. Sometimes several acids are formed by using different proportions of the same elements. The termination " ous " is then used in the name of the one with a relatively low percentage of O, and the termination " ic " in the name of the one with a relatively high percentage of that element. Thus, H 2 SO3 is sulphurous, and H 2 SO4 is sulphuric acid. Among the other commoner inorganic acids are the following: Hydrochloric (HC1), hydrofluoric (HF), silicic (H 4 SiO 4 ), carbonic (H 2 CO 3 ), nitric (HNOa), boric or boracic (H^BOs), and phosphoric (H 3 P0 4 ). ELEMENTARY PRINCIPLES OF CHEMISTRY 71 Bases, Salts, and Chemical Equations. Bases are such substances as impart a blue color to red litmus paper, or which are capable of replacing all or part of the H in an acid and forming a substance called a salt. Bases are always metals, combina- tions of metal and O, or the latter with the addition of H. Thus, when Na (a base) is added to HC1 (an acid), NaCl (a salt) is formed and H is liberated. Such changes as this, called chemical reactions, may be expressed in the form of an equation, thus: HCl + Na = NaCl + H. ZnO (base)+2HNO 3 (acid)=Zn(NO 3 ) 2 (salt) + H 2 O (water). The opposite sides of chemical equations must always contain the same number of atoms of each element involved. When this is true, they are said to balance. From the above discussion, it is plain that a salt may be defined as a compound that is formed by the reaction of an acid and a base; all or part of the H in the acid is replaced by one or more metals. If a salt is formed from an acid with the " ous " termination, its name terminates in " ite." Thus, NagSOs (formed from sulphurous acid) is known as sodium sulphite or sulphite of sodium. When the salt is formed from an acid with the " ic " termination, its name terminates in " ate." Thus, the Zn(NO 3 ) 2 obtained in the reaction recently equated is called zinc nitrate or nitrate of zinc. 72 BLOWPIPE AXALYSIS In cases where lack of knowledge makes it impossible to decide whether an " ic " or an " ous " acid was involved in the formation of a salt, it is usually safe to use the " ate " the commoner- termination, calling the salts sulphates, carbonates, phosphates, etc. Additional Nomenclature. When an element is combined with a non-metal, the resulting com- pound is named by adding the termination " ide " to the root of the name of the non-metal. The following list will illustrate this usage: FeAs 2 is iron arsenide or arsenide of iron, A^CUfis chloride of silver, AuTe2 is telluride of lead, and Fe 2 O 3 is oxide of iron. Sometimes compounds of this type are formed in which more than one element combines with the non-metal, or one element may combine with two different non-metals, as in the following instances: CuFeS2 is copper, iron sulphide, and Co2As 2 S 2 (CoS 2 .CoAs 2 ) is cobalt arsenide and sulphide. Care should be taken not to confuse the " ite " and " ide " terminations. ELEMENTARY PRINCIPLES OF CHEMISTRY 73 TABLE OF ELEMENTS WITH THEIR SYMBOLS AND ATOMIC WEIGHTS Name. Sym- bol. At. Wts. Name. Sym- bol. At. Wts. Al minum Al Nd 6 . Sb Neon Ne n imony A Nickel Ni 58 7 A 8 ' As N R Ba Os Beryllium Bismuth Be Bi B 9-1 208. 5 Oxygen Palladium o Pd p 16 106.5 B ' Br 79 96 Platinum Pt Cadmium Cd Cs 112.4 Potassium K Pr 39-iS Calcium Ca c 40.1 Radium Rhodium Ra Rh 225 Cerium Chlorine Chromium Cobaft Columbium Copper Ce Cl Cr Co Cb Cu Er 140.25 35-45 52-' 59 94 6.? . 6 1 66 Rubidium Ruthenium Samarium Scandium Selenium Silicon Silver Rb Ru Sm Sc Se Si Ag 85.4 101.7 15 44.1 79-2 28.4 F Sodium Na Gadolinium Gallium Germanium Gold Gd Ga Ge Au He IS'' 70 72-5 197-2 Strontium Sulphur Tantalum Tellurium Sr S Ta Te Tb 87-6 32 .06 183 127.6 1 60 H -d H Thallium Tl Ind;um In I 114 126 85 Thorium Thulium Th Tm 232.5 Iridium Ir Fe 193 Tin Sn Ti 119 48 I Krypton Lanthanum Lead Lithium Magnesium Manganese Mercury Molybdenum Kr La Pb Li Mg Mn Hg Mo 81. 138. 206. 7- 3 24.36 55 200 96 Tungsten Uranium Vanadium Xenon Ytterbium Yttrium '. . . 1 Zinc : Zirconium i W IT V Xe Yb Yt Zn Zr 184 238.S 51-2 128 '73 89 65-4 90.6 INDEX PAGE Acids (defined) 70 Alloys (defined) 63 Aluminum, minerals containing 51 Aluminum, test for 48 Antimony, minerals containing 52 Antimony, tests for 48 Anvil 4 Arsenic, minerals containing 52 Arsenic, tests for 48 Assay (defined) 10 " ate " termination of salts 71 Atomic weight (defined) 67 Atomic weights, table of 73 Atoms (defined) 64 Barium, minerals containing 53 Barium, tests for 48 Bases (defined) 71 Bead tests, borax 25 Bead tests, microcosmic salt 32 Bead tests, salt of phosphorus - - 32 Bead tests, sodium ammonium phosphate 32 Bead tests, table of 30 Bismuth flux (defined) 5 Bismuth, minerals containing 53 Bismuth, tests for 48 Blast, production of ... 6 Blowpipe .... i Blowpipe analysis (defined) 9 76 INDEX Blowpipe analysis, outline for ........................... 4^ Blowpipe operations .................................... r> Borax beads, tests with ................................. 25 Boron, minerals containing .............................. j ^ Boron, tests for. . ...................................... 48 Cadmium, minerals containing ........................... c^ Cadmium, tests for ............................... ...... 48 Calcium, minerals containing ............................ ^ Calcium, tests for ...................................... 48 Carbonate minerals ..................................... 6 1 Carbonate, test for a .................................... 49 Charcoal borer ......................................... c; Charcoal supports ...................................... 3 Chemical compound (defined) ..................... *. ..... 63 Chemical equations ..................................... 71 Chemistry, elementary principles of ....................... 62 Chromium, minerals containing .......................... 5 ; Chromium, tests for .................................... 48 Closed tubes ........................................... 4 Closed tubes, tests in .............. . ..................... 19 Cobalt nitrate coloration tests ............................ 39 Cobalt, minerals containing ............................. ^4 Cobalt, tests for ....................................... 48 Compounds, chemical (defined) .......................... 63 Copper, minerals containing ............................. ^4 Copper, tests for ....................... ................ 48 Decrepitation (defined). ... ............ . . 1 1 Determination of minerals ............................... 50 Elements (defined) ..................................... 62 Elements detectable with the blowpipe .................... 9 Elements, table of all ................................... 73 Flame, hottest ......................................... 8 Flame, oxidizing ....................................... 9 IXDEX 77 PAOB Flame, reducing 8 Flame tests ^ Fluorine, minerals containing ^4 Fluorine, tests for 48 Flux 1 6 Forceps, platinum-tipped ^ 1'ormuhc (defined) 65 Gold, minerals containing 54 Gold, tesls for 48 Hammer 4 Holder for platinum wire -5 Holders for tubes 4 " ic " termination of acids 71 " ide " termination of salts , . . . 72 Index to minerals containing the various elements 51 Index to tests yielded by the various elements 47 Instruments user! in blowpipe analysis i Iron, minerals containing , 55 Iron, tests for 48 " ite " termination of salts 71 Lamps 2 Lead, minerals containing 55 Lead, tests for 48 Lithium, 7ninerals containing 55 Lithium, tests for. 48 Magnesium, minerals containing 56 Magnesium, tests for 48 Ma-net 4 Manganese, minerals containing 56 Manganese, tests for 48 Mercury, minerals containing 56 Mercury, tests for 4eads, tests with Minerals containing the various elements. Minerals, determination of Molecular weight (defined) Molecules (defined) Molybdenum, minerals containing Molybdenum, tests for Nickel, minerals containing. Nickel, tests for Oil for lamp . j Open tubes ! Open tubes, tests in _> ^ " ous " termination of acids 71 Outline for qualitative blowpipe analysis ^ Oxidizing flame 7 Parenthesis, use of (in chemical formuh:) 66 Phosphorus, minerals containing ^6 Phosphorus, tests for 48 Platinum-tipped forceps 3 Platinum wire 3 Platinum wire holders 3 Potassium, minerals containing 57 Potassium, tests for 48 Qualitative analysis (defined). . '. 42 Quantitative analysis (defined) 42 Reagent bottles 5 Reagents 5 Reducing flame 8 Salt of phosphorus l^eads, tests with 32 Salts (defined) 71 Saturated bead (defined) 27 79 PAGE Selenium, minerals containing 57 Selenium, tests for 48 Silicate minerals 61 Silicate, test for a 49 Silver, minerals containing ^7 Silver, tests for . . ., 48 Sodium ammonium phosphate lx;ads, tests with 32 Sodium, minerals containing ^7 Sodium, tests for 48 Strontium, minerals containing 57 Strontium, tests for 49 Sublimates (defined) 10 Sulphur, minerals containing 58 Sulphur, tests for 49 Symbols (defined) 65 Table of bead tests 30 Tellurium, minerals containing 59 Tellurium, tests for 49 Tests, flame 33 Tests for the various elements, index to 47 Tests in closed tubes with acid potassium sulphate 22 Tests in closed tubes without flux 20 Tests in closed tubes with sodium carbonate flux 22 Tests in open tubes 23 Tests with acids 40 Tests with borax beads 25 Tests with cobalt nitrate (coloration tests). '. 39 Tests with microcosmic salt beads 33 Tests with salt of phosphorus beads 32 Tests with sodium ammonium phosphate lx:ads. . . ." 33 Tin, minerals containing 59 Tin, tests for 49 Titanium, minerals containing 59 Titanium, tests for 49 Treatment on charcoal with flux 15 Treatment on charcoal without flux . . . . 10 80 IXDEX PAGE Tubes, closed 4 Tubes, open 4 Tungsten, minerals containing 59 Tungsten, tests for 40 Uranium, minerals containing 50 Uranium, tests for .... 49 Vanadium, minerals ( ontaining ^g Vanadium, tests for 49 Volatile (defined) 12 Water, minerals containing 60 Water, tests for. . 49 Wire, platinum } Zinc, minerals containing 50 Zinc, tests for 19 THE DENVER FIRE CLAY COMPANY MANUFACTURERS, IMPORTERS AND EXPORTERS OF ASSAYERS' AND CHEMISTS' SUPPLIES, SCHOOL APPARATUS, Etc, Salt Lake City, Utah, . Denver, Col. We carry in stock a full line of Blowpipe Apparatus and Reagents for Mineral Determinations, including a PORTABLE SET OF BLOWPIPE APPARATUS AND REAGENTS This outfit contains the instruments and chemicals required to make any of the tests described in the " Pocket Handbook of Blowpipe- Analysis." It was specially pre- pared to conform to the specifications of Prof. G. M-on- tague Butler, and is the most compact and practical outfit now on the market at a reasonable price. WRITE FOR DESCRIPTIVE BULLETIN MANUFACTURERS OF Clay Crucibles, Muffles, Furnaces for Assaying, Crushers, Bullion Furnaces. WRITE FOR DESCRIPTIVE BULLETINS THE DENVER FIRE CLAY COMPANY University of California SOUTHERN REGIONAL LIBRARY FACILITY 305 De Neve Drive - Parking Lot 17 Box 951388 LOS ANGELES, CALIFORNIA 90095-1388 Return this material to the library from which it was borrowed. QL, DUE JAN 1 2005 Subject to Recall This book is DUE on the last date stamped below JUN 4 JANS 19651 10m-ll,'50(2555)470 953