.D AND DESCRIPTIVE LOGUE LIBRARY OF 1 IVERSITYofCALE LICK OBSERVAT NEGRETTI & ZAMBRA'S /; ENCYCLOPEDIC ILLUSTRATED AND DESCRIPTIVE REFERENCE CATALOGUE - OF OPTICAL, MATHEMATICAL, PHYSICAL, PHOTOGRAPHIC, AND STANDARD METEOROLOGICAL INSTRUMENTS, MANUFACTURED AND SOLD BY THEM. NEGRETTI AND ZAMBRA, ptidans ani jJrientifit Jfnsirununt Utabrs to HER MAJESTY THE QUEEN; H.R.H. THE PRINCE OF WALES; THE ROYAL OBSERVATORY, GREENWICH; THE ADMIRALTY; BOARD OF TRADE ; THE ROYAL BRITISH METEOROLOGICAL SOCIETY; THE OBSERVATORIES, KEW, TORONTO, WASHINGTON, VICTORIA; AND CAPE OF GOOD HOPE. HOLBORN VIADUCT, E.G., 45, COBNHILL, E.G., and 122, REGENT STREET, W., PHOTOGRAPHERS TO THE CRYSTAL PALACE, SYDENHAM. LONDON. PRICE FIVE SHILLINGS AND SIXPENCE. Revised and Corrected Edition. Oi vvv^ MAYMAN BROTHERS AND LILLY, PRINTERS, HATTON HOUSE, FARRINGDON ROAD. LONDON. E.G. NEGRETTI & ZAMBRA, photographers to tbe Crystal palace Company OPTICIANS, AND METEOROLOGICAL INSTRUMENT MAKERS, CERAMIC COURT, CRYSTAL PALACE, SYDENHAM, S,E, NEGRETTI & ZAMBRA' S PHOTOGRAPHIC ROOMS Are open daily, and Portraits taken in all the most approved Styles, from Carte de Visite to Life Size. MINIATURES, CARTE DE VISITE, AND OTHER PORTRAITS ENLARGED, PORTRAITS FROM LIFE. OR ENLARGEMENTS COLOURED IN THE HIGHEST AND MOST FINISHED STYLE EITHER IN OIL OR WATER COLOURS. All kinds of Photographic Work undertaken, and executed with ability and despatch. Price Lixts Posted Free. XEGRETTI & ZAMBRA have, in connection with their Photographic Rooms in the Ceramic Court, Crystal Palace, a department for the sale of Optical, Meteorological, Philosophical, and Photographic Instruments; and respectfully invite inspection of their extensive stock, conveniently arranged for examination, every facility for so doing- being- afforded by the Assistants in attendance. NEGHETTI & CAMERA, Opticians anfc meteorological instrument TO HER MAJESTY THE QUEEN, AND H. R. H. THE PRINCE OF WALES A SPECIAL PRIZE MEDAL was awarded at the International Exhibition of 1 862 to Negretti and Zambra ; and the AUSTRIAN GOLD MEDAL was also presented to the Firm for the EXCELLENCE oj their PHOTOGRAPHS UPON GLASS, 6V. 740482 HONORARY AWARDS TO NEGRETTI AND ZAMBRA. 1881. 1882. 1883. 1883. 1884. 1851. The only Prixe Medal for Meteorological Instruments was awarded to Negretti and Zambra. 1855. " Honourable Mention." Paris Exhibition. The ew Committee exhibited among their Apparatus one of -A 7 ". <$[ Z*s. Patent Maximum Thermometers ; the Jury awarded an Honour able Mention for this Instrument. Negretti and Zambra not having exhibited at all. The "Austrian Gold Medal." For Stereoscopic Photographic Views on Glass. ^ 1862. Two Prize Medals. J. Meteorological Instruments. The terms of the Award being as follows : " For many important inventions and improvements, together with accuracy and excellence in objects exhibited." II. Photographic Transparencies, "for beauty and excellence of, and adaptation of Photography to 'Book Illustrations" 1875. A Prize Medal. Santiago, Chili, awarded for their exhibited collection of Optical and Physical Instruments. 1876. Three Prize Medals. Philadelphia, "/or Meteorological Instruments ; " "for Thermometers" and "for Microscopes J*' 1878. A Gold Medal, Paris. The only Gold Medal awarded for Meteorological Instruments in the British Section. Fisheries Exhibition, Norwich. A Silver Medal and Diploma for Deep Sea Recording Thermometers and Sextants. Fisheries Exhibition, Edinburgh. A Silver Medal for Deep Sea Recording Thermometers, &c. Buitenzorg, Batavia, Java Exhibition. A Gold Medal for general excellence of Optical Instruments exhibited. International Fisheries Exhibition, London. A Gold Medal for Meteorological Instruments. A Silver Medal for Deep Sea Recording Thermometers. A Bronze Medal for Current Meter. A Gold Medal for Standard Barometers. International Health Exhibition, London. A Gold Medal for Hourly Recording and other Registering Thermometers. NEGRETTI AND ZAMBRA'S INVENTIONS AND IMPROVEMENTS. 1. Enamelling the centre or back of Thermometer Tubes. By this invention, Negretti and Zambra have been enabled to make Thermometers at least twenty times more sensitive than heretofore. The delicate Clinical Thermometers now so extensively used could never have been efficiently constructed without the aid of the enamelled tube. See Sensitive Thermometers, pages 32 and 160. 2. Negretti and Zambra's Patent Self-Registering Maximum Thermometer. Pp. 36 to 45. For a Report on the value of this Thermometer by the Kew Committee see pages 37 and 38. 3. The Application of Porcelain and Enamelled White Glass Scales to Barometers and Thermometers, the divisions being permanently etclied or painted thereon ; a plan now universally adopted by all makers. 4. Negretti and Zambra's Patent Mercurial Minimum Thermometers (two patents). See pages 47 to 50. 5. Negretti and Zambra's Patent Self -Registering Maximum Thermometer, specially arranged for obtaining underground temperatures, Mines, Springs, &c., Marine service, Solar Observations, &c., &c. Seepages 42, 44, 145, 171, and 172. 6. FitzRoy's Marine Gun Barometer, constructed for use in Her Majesty's Navy, by Negretti and Zambra, the only one adopted and in use in Her Majesty's vessels. See pages 11 and 12. 7. FitzRoy's Storm or Life-Boat Service Barometer. See page 143. 8. Pocket and Watch- sized Aneroid Barometer. The first Pocket Aneroid ever produced was manufactured by Negretti and Zambra for the late Admiral FitzRoy. See pages 24 to 27. 9. The Double Bulb Deep Sea Thermometer, first constructed and supplied to Her Majesty's Navy by Negretti and Zambra in 1 862. For full particulars and the history of this important invention see pages 63, 64, 65, and 173. 10. Improved Standard Mercurial Deep-Sea Thermometer, the only Instrument capable of giving correct temperatures of the bottom or any intermediate depth of the sea. See pages 66 and 67. 11- Negretti and Zambra's Patent Strengthened Glass Hydrometer. Seepage 194. 12. A Portable form of the Open Range Glycerine Barometer. See page 18. 13. Self Recording Aneroid Barometers with various Improvements. See pages 27 and 28. 14. Improved Self-Recording Barographs, Thermographs, Hygrometers. Seepages 30, 53 to 56, 130. 15- Negretti and Zambra's Patent Apparatus for recording Hourly Temperatures. Seepages 55 and 78. 16. Recording Anemometers, Electrical. Various arrangements constructed by Negretti and Zambra. CONTENTS. PAGE Preface v. to vii Standard Meteorological Instruments and Meteorological Publications . . 1 to 133 Barometers, Aneroids, Thermometers, and Hygrometers . . . 134 to 151, 152 to 175 Hydrometers and Saccharometers 176 to 195 Steam, Vacuum, Hydraulic, and Gas Pressure Gauges, and Counting Machines 198 to 210 Surveying Instruments, Land Chains, Measures, &c 283 to 307 Nautical Instruments, Sextants, Quadrants, Ships' Lamps, Logs, Mariners' Compasses, &c., and Sun Dials 308 to 327 Mathematical Drawing Instruments, Scales and Rules 330 to 349 Globes and Orreries 328 to 329 Spectacles, Pocket and Hand Magnifiers 213 to 224 Various Optical Instruments 225 to 228 Opera, Race, and Field Glasses *234 to 240 Microscopes and Apparatus 256 to 275 Telescopes 241 to 255 Polarising Apparatus 277 to 280 Stereoscopes and Slides . . . 229 to 233 Magic Lanterns and Dissolving View Apparatus 350 to 374 Spectrum Apparatus, and the Radiometer 276, 281, 282 Chemical Apparatus, of Glass, Porcelain, and Earthenware .... 375 to 394 Apparatus for Organic Analysis 394, 395 Chemical and Philosophical Apparatus and Instruments, of Metal, &c. . . 396 to 410 Chemical Cabinets and Portable Laboratories 410,411 Frictional Electrical Apparatus 412 to 427 Voltaic or Galvanic Apparatus 428 to 436 Electro-Metallurgical Apparatus 440 to 442 Magnetic and Electro-Magnetic Apparatus 443 to 449 Electric Bells and Alarms 459 to 467 Electric Light Apparatus 437 to 439 Thevmo-Electric Apparatus 450' Induction Coils and Apparatus 451 to 455 Medical Galvanic and Magnetic Apparatus 455 to 459 Pneumatic Apparatus 468 to 476 Hydrostatics and Hydraulics 477 to 480 Photometers 497 Acoustic Instruments, &c 494 Mechanics and Dynamics 491 to 495 Models of Steam Engines, &c., Apparatus for Illustrating the Phenomena of Heat 481 to 490 Portable Steam Engines ) .... 211 Gun Metal Fittings, for Steam Engines and Boilers, &c. ' .... 210 Bourdon's Steam Gauges 205 to 210 Telegraph Instruments and Apparatus 449, 461, 466 Surgical and Medical Instruments, &c. 498 to 503 Soda Water Machinery and Diving Apparatus, and Ice Machines . . . 504 to 508 Hydraulic Machinery 509 Gas Motors 510, 511 Photographic Apparatus 517 to 553 Appendix 554 General Reference Index 567 Mineralogical and Geological Collections . 503 PKEFACE. IN again submitting to our numerous friends and patrons a greatly enlarged and revised edition of our Encyclopaedic Catalogue, we do so with some decree of pride, firstly, that all previous editions have been such as to command the extensive patronage bestowed upon them ; and, secondly, from the award made known at the " Great International Exhibition at Paris," that the superiority and excellence of our instruments, which gained for us the only Prize Medal in 1851, is still maintained, and manifested by the fact that at Paris in 1873 we had awarded to us the ONLY GOLD MEDAL given for our class of instruments in the British Section. This is further confirmed by the award of THREE GOLD MEDJLL>, SILVER, and BRONZE MEDALS at the International Exhibitions, London, 1883-1884, and other awards specified on page iii. In this edition, as in all that have preceded it, our endeavour has been to make the the work, not merely a list of prices, but in reality a guide for those who are purchasing Scientific Instruments and Apparatus generally. All instruments are well described, some more fully than others, depending upon the importance of the apparatus or article under consideration. Our Meteorological Instruments we particularly recommend to those who are about to commence making observations in the science of Meteorologv as being the most recently improved and reliable that can possibly be produced. In confirmation of this we have only to state that for nearly forty years our firm have had the honour of supplying Standard Instruments to all the most important Meteorological Observatories, Scientific Institutions, and Govern- ments of the World ; most of the Geographical and Deep Sea Exploring Expeditions of the last thirty years have been supplied with our Instruments. To enumerate our various inventions and improvements here would be, with few exceptions, to repeat all that has been said in previous editions ; as it would be tedious, we specify these Inventions and Improvements on pao-e iv., and indicate the section or page in the Catalogue where they will be found fully described. Our doing so must not be taken as an act of egotism ; but for the special purpose of placing on record that we are the Inventors and Improvers of such instruments, as many of our inventions have been appropriated by manufacturers, and sold without the slightest acknowledgment of their origin. Our extensive business knowledge and experience in each of the various sections of our Trade enables us to obtain full and correct information respecting any new Instruments or Inventions : hence we are in a position to supply to our Correspondents any Specialities made and sold by other firms at their advertised or Catalogue prices. Viii PREFACE. At page v. will be found a Table of Contents, referring to the pages where any particular section or class of apparatus will be found, and at page 567 an extensive general Index, giving the marginal number or page for each Instrument: these, combined with upwards of Thirteen Hundred "Wood Engravings (a large proportion of them new), will assist the reader in searching for any particular item. When Orders are transmitted in Foreign Languages, N". & Z. advise their friends to send verbatim copies of such orders in the original language, as it often occurs that where the order has been translated and copied by persons unacquainted with the nature or use of the articles written for, serious errors arise in the carrying out their correspondents' commands. Correspondents may, if preferable to them, write in French, Italian, Spanish, or German. A liberal commission allowed to Merchants, Shippers, or Agents on large transactions. Merchants favouring us with copies of their clients' orders will have special quotations furnished to them if desired. Full and explicit instructions should accompany orders as to the Address, mode of Conveyance, Shipment, Insurance, Consular Forms, and Declarations, etc., etc. Foreign or Country orders must be accompanied by an adequate Remittance or Order for Payment, or Satisfactory Reference in London. Every possible care being taken in packing Apparatus and Instruments to insure safety in carriage, ibe cannot be responsible for any damage that may occur in transit after the goods leave our establishment. The probable expense of Packing Cases, Tin or Zinc-lined, may be taken at say from 5 to 10 per cent, on the value of articles of ordinary dimensions and weight. Yery bulky or extremely heavy goods can. hardly be estimated for ; but 1ST. & Z. will undertake that all packages, &c., shall be supplied at the lowest possible net charge. All communications from abroad should be directed to the Chier Establishment, Negretti & Zambra, Holborn Viaduct, E.G., London. Letters for their Branches to be specially addressed 45, Cornhill, E.G. ; 122, Regent Street, W. ; or, Negretti & Zambra's Photographic Department, Crystal Palace, Sydenham, S.E. The compilation and revision of this New Edition of our Catalogue has again been entrusted by us to Mr. R. WILLATS, the Manager of our retail department at Holborn Viaduct ; and we hope that both as a Price List and a Book of Reference it will be found much superior to its predecessors. NEGEETTI & ZAMBEA. ERRATA. PAGE. 7 Last line 0'45 should read 0'6. 20 Fig. 21. Price should read 27 !<-. 27 Last line, 18s., should read 15s. 32 No. 39. For T \jth of degree read ^ths. 58 Last line, 20s., should read 7s. (This instrument has been considerably improved since catalogue was printed. Full particulars forwarded on application.) 65 The line "1 Cubic Foot of Sea Water" should read "Fresh Water" (see page 558). 67 Price of Magnaghi Pattern Deep Sea Thermometer, 5 10s. 75 No. 98. 63s. should read 50s. 94 No. 133 is no longer made, having been superseded by No. 132. 102 No. 144. 4-inch Anemometer, 63s. should read 60s. 114 No. 158 is no longer made. 124 No. 1 Set of Instruments, instead of 330 to 450, read 170 to 250. 131 Dip Circle No. 136. 35 should read 40. 132 Prices of Charts for figures 21 and 29. 25s. should read 21s. For fig. 28 read 15s. For Anemometers and Tide Gauges read 35s. 133 Negretti and Zambra's Treatise and Ksemtz's Meteorology are both out of print. 143 No. 171. FitzRoy Barometer, 6 10s., should read 6 6s. 14 Fig. 182 should read 183. Fig. 183 should read 182. 149 No. 199 can also be supplied at 5 5s. 157 No. 267 14-inch, 10s., should read 8s. 6d. 159 No. 299. 400 should read 140?. No. 300. 600 should read 212. No. 301 should read to 600. 162 The Thermometers, Nos. 313, 314, and 315, are not to be recommended, and are superseded by Nos. 316 and 317. 163 No. 316 are also supplied on Boxwood Scales at 5s. 6d. and 7s. 6d. Porcelain Scale in Japanned Metal Case, 10s. 6d. should read 7s. 6d. No. 317. 12s. 6d, should read 10s. 6d. No. 321. 10s. 6d. should read 7s. 6d. No. 322. 12s. 6d. should read 10s. 6d. 168 No. 366. 16s. 6d. should read 15s. 169 No. 386. 130 should read 110. 177 No. 423. 27s. 6d. should read 21s. 186 No. 485. 16s. 6s. should read 12s. 6d. No. 486. 10s. 6d. should read 7s. 6d. 188 No. 510 is no longer made. No. 514. Fig. 466 should read 514. No. 515. Fig. 467 should read 515. No. 517. Fig. 469 should read 517. 196 No. 559. " Vacuum Gauge " should read " Pressure Gauge." Fig. 459 should read 559. 199 Fig. 578 should read 587. 201 Fig. A should read C. Fig. C should read A. Small Machine Counter " with 4 figures at 63s." should read " with 6 figures and reciprocating." ERRATA. PAGE. 223 Fig. 697 should read 679. 226 Fig 40 should read 740. 250 No. 859, referred to as fig. 859, should read fig. 861. 251 No 861 should read 859. 252 No. 864. For 190 diameters read 100. 253 No. 866. 8 8s, should read S. 254 No. 868. 8 8s. should read 8. No. 871. 14 should read 14 10s. 200 should read 190. 300 should read 280. 400 should read 390. 268 No. 925. ith Object Glass 4 10s., should read 6 10s. ith ditto 5 should read 7 10s. 272 No. 995 6s. should read 5s. 275 No. 1042. 8 8s. should read 7 7s. No. 1044. 10s. 6d. should read 6s. 6d. No. 1045. 12s. 6d. should read 8s. 6d. 280 No. 1075 are also supplied at 5s. and 7s, 6 d. 285 No. 1115. 20 seconds should read 30. 291 No. 1155. 18 18s. should read 19 10s. 292 No. 1165. 36s. should read 35s. 297 No. 1186. 3 3s. should read 3 10s. 307 30-inch Pentagraph, 10 10s., should read 9 10s. 308 No. 1293. 5-inch should read 6-inch. 317 No. 1345. 3 3s. should read 2 2s. 325 No. 1404. 5s. should read 3s. No. 1407. Is. should read Is. 9d. No. 1418. Is. should read Is. 6d. 356 No. 1761. 12 12s. should read 10 10s. 397 No. 2167.* 16s. should read 10s. 6d. 398 No. 2181 is no longer made. 412 No. 2380. 9-inch at 63s. should read 10-inch 432 Fig. 1888 should read 2564. 434 No. 2554. No. 1 size, 5s. 6d. should read 4s. 6d. No. 2 size, 4s., should read 3s. 6d. No. 3 size, 3s. 6d., should read 3s. No. 2604 has now been superseded by machines of improved construction. 447 Fig. 2079 should read 2709. 448 No. 2709 is no longer made. 458 No. 2784. 32s. should read 30s. 477 No. 2912. Fig 2612 should read 2912. 479 Fig. 9240 should read 2940. 481 Fig. 2995 should read 2955. 483 No. 2951. Fig. 2251 should read 2951. No. 2954. No. 2144 should read fig. 3044. 490 No. 3009. Figs. 2109 and 2109* should read figs. 3009 and 3009*, 493 Fig. 2694 should read 3042. 517 No. 3159. For plate at 3 3s. read \ plate. 545 No. 3282. 5 15s. should read 6 5s. NEGRETTI AND ZAMBRA'S DESCRIPTIVE CATALOGUE. STANDARD METEOROLOGICAL INSTRUMENTS. THE practical usefulness of Meteorological Instruments as weather indicators, and their increasing employment for Scientific and Sanitary investigation, render a knowledge of their construction and principles desirable to all. Impressed with the idea that we shall be supplying a want, in giving simple descriptions of those now in use, we have endeavoured to condense such information regarding the instruments used in Meteorology in the present section of our Catalogue. Every Meteorological Instrument of any practical value being described, with plain instructions for using them, purchasers will be enabled to select such as seem to them most suited to their requirements. For convenience of reference and comparison we arrange and describe the different instruments used for Meteorological observation under the following headings, viz. : Instruments to show, 1st, the pressure of the atmosphere; 2nd, the temperature of the air ; 3rd, the absorption and radiation of the sun's heat by the earth's surface ; 4th, the humidity of the air ; 5th, the amount and duration of rainfall ; 6th, the direction, the horizontal pressure, and the velocity of winds ; 7th, the electric condition of the atmosphere, the prevalence and activity of ozone, magnetic, and tidal phenomena, &c., &c. B INSTRUMENTS FOR ASCERTAINING THE ATMOSPHERIC PRESSURE, BAEOMETEES. 1. Principle of the Barometer. The first instrument which gave the exact measure of the pressure of the atmosphere was invented by Torricelli, a Florentine pupil of Galileo, in 1643. It is constructed as follows : A glass tube, C D (fig. 1), about 34 inches long, and from two to four-tenths of an inch in diameter of bore, having one end dosed, is filled with mercury. In a cup, B, a quantity of mercury is also poured. Then, placing a finger securely over the open end, C, invert the tube vertically over the cup, and remove the finger when the end of the tube dips into the mercury. The mercury in the tube then partly falls out, bat a column, A B, about 30 inches in height, remains supported. This column is a weight of mercury, the pressure of which upon the surface of that in the cup is pre- cisely equivalent to the corresponding pres- sure of the atmosphere. As the atmospheric pressure varies, the length of this mercurial column also changes. It is by no means constant in its height ; in fact, it is very seldom stationary, but is constantly rising or falling in the tube. It is, there- fore, an instrument by which the fluctuations taking place in the pressure of the atmosphere, arising from changes in its weight and elasticity, can be shown and measured. It has obtained the name Barometer, or measurer of heaviness, a word certainly not happily expressive of the utility of the invention. If the bore of the barometer tube be uniform throughout its length, and have its sectional area equal to a square inch, it is evident that the length of the column, which is supported by the pressure of the air, expresses the number of cubic inches of mercury which compose it. The weight of this mercury, therefore, represents the statical pressure of the atmosphere upon a square inch of surface. In England the annual mean height of the barometric column, reduced to the sea-level, and to the temperature of 32 Fahrenheit, is about 29'95 inches. A cubic inch of mercury at this temperature has been ascertained to weigh 0-43967 Ibs. avoirdupois. Hence 29'95 xO'48967^14'67 Ibs., is the mean NEGEETTI AND ZAMBKA, HOLBOEN VIADUCT, E.G. 3 value of the pressure of the atmosphere on each square inch of surface, near the sea-level, about the latitude of 50 degrees. Nearer the equator this mean pressure is somewhat greater ; nearer the poles, somewhat less. For common practical calculations it is assumed to be 15 Ibs. on the square inch. When it became apparent that the movements of the barometric column furnished indi- cations of the probable coming "changes in the weather, an attempt was made to deduce from recorded observations the barometric height corresponding to the most notable characteristics of weather. It was found that for fine dry weather the mercury in the barometer at the sea-level generally stood above 30 inches ; changeable weather happened when it ranged from 30 to 29 inches, and when rainy or stormy weather occurred it was even lower. Thus, it became the practice to place upon barometer scales words (Fair, Change, Rain, &c.), indicatory of the weather likely to accompany, or follow, the movements of the mercury ; and the instruments bearing them obtained the name " Weather Glasses." COMPARISON OF THE ENGLISH AND METRICAL SCALES OF BAROMETERS AT ALL TEMPERATURES COMMON TO BOTH. Inches. 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 BY F. F. TUCKETT, ESQ. Millimetres. Inches. 812-5312 16 787-1396 15 761-7480 14 736-3564 13 710-9648 12 685-5732 11 660-1816 10 634-7900 9 609-3984 8 584-0068 7 558-6152 6 533-2236 5 507-8320 4 482-4404 3 457-0488 2 431-6572 1 Millimetres. 406-2656 380-8740 355-4824 330-0908 304-6992 279-3076 253-9160 228-5244 203-1328 177-7412 152-3496 126-9580 101-5664 76-1748 50-7832 253916 B 2 NEGEETTI AND ZAMBEA, HOLBOKN TIADUCT, E.G., s II FIG, 2. INSTRUMENTS FOR ASCERTAINING THE ATMOSPHERIC PRESSURE. STANDAKD BAEOMETEES. 2. Negretti & Zambra's Standard Barometers are constructed on Fortin's principle,* which has been proved to be the most reliable and convenient arrangement yefc introduced. The level of the mercury in the cistern being adjusted previous to each observation to a fixed zero point of ivory, loss of mercury from leakage or oxidation is of little or no importance, and does not affect the accuracy of the readings of the instrument. The tubes are of varying internal diameter, according to the price of each barometer. These tubes are filled with pure mercury, very carefully boiled in the tube to perfectly expel all air or moisture. The barometer tube is mounted in a brass tubular frame, extending throughout its whole length ; the upper portion of it has two longitudinal openings 5 on one side of the front opening is the barometrical scale of English inches, divided to show, by means of a vernier, -^oth of an inch ; on the opposite side is some, times divided a scale of French millimetres, reading also by a vernier to y^th of a millimetre. The reservoir or cistern of the barometer is of glass, closed at bottom by means of a leather bag, acted upon by a thumb-screw passing through the bottom of an arrangement of brass- work, by which it is protected. A delicate thermometer with the scale divided on its stem, so arranged as to give as accurately as possible the temperatures of the column of mercury, is attached to the brass tube. A mahogany board, with brass bracket and ring, with three adjusting screws for suspending and adjusting the barometer, is supplied with each instrument. * This form of barometer, now universally adopted by all makers, was originally introduced by Negretti and Zambra. 45, CORNHILL, E.G., AND 122, "REGENT STREET, W., LONDON. Fortin's barometer cistern shown in section by fig. 3, is formed of a glass cylinder, which allows of the level of the mercury within being seen. The bottom of the cylinder is made of flexible leather, like a bag, so as to allow of being pushed up or lowered by means of a screw, D B, worked from beneath. This screw moves through the bottom of a brass cylinder, C C, which is fixed outside, and protects the glass cylinder containing the mercury. At the top of the interior of the cistern is fixed a small piece of ivory, .A, the point of which exactly coincides with the zero of the scale. This screw and moveable cistern-bottom FIG. 3. serve also to render the barometer portable, by con- fining the mercury in the tube, and preventing its descending into the cistern. Fig. 4 exhibits the external construction of the cistern portion of a standard barometer. S S are metal screws that secure the glass cylinder or cistern G Gr partly filled with mercury, M, through this the tube T passes down into the flexible leather bag, with which the instrument is adjusted or made portable by the screw, D B, as previously described. At P is shown the white ivory zero point to which the level of the mercury in the glass cistern is always corrected previous to reading off the height of the mercurial column. This ivory point is seen at A in the section FIG. 4. fi o- 3, and at P in fig. 4. Directions for fixing Hie Barometer. In selecting a position for a barometer care should be taken to place it so that the sun cannot shine upon it, and that it is not affected by direct heat from a fire. The cistern should be from two to three feet above the ground, which will give a height for observing convenient to most persons. Having determined upon the position in which to place the instrument, fix the mahogany board as nearly vertical as possible ; and ascer- tain if the barometer is perfectly free from air, in the following manner : lower the adjusting screw at the bottom of the cistern several turns, so that the mercury in the tube, when held upright, may fall two or three inches from the top ; then slightly incline the instrument from the vertical position, and if the mercury in striking the top elicit a sharp tap, the instrument is perfect. If the tap be dull, or not heard at all, there is air above the mercury ; this must be driven into the cistern by partially rescrewing and then inverting the instrument, and gently tapping it with the hand. The barometer being in perfect condition, 6 NBGRETTI AND ZAMBEA, HOLBOEN VIADUCT, B.C., suspend it on the brass bracket, its cistern passing through the ring at bottom, and allow it to find its vertical position ; after which firmly clamp it by means of the three clamping screws. Directions for taking an Observation. Having taken the temperature by the attached thermometer, the mercury in the cistern must be raised or lowered by means of the thumb-screw (s), fig. 2, until the ivory point (E), and its reflected image in the mer- cury (D), are just in contact ; the vernier is then moved by means of the milled head, until its lower edge just excludes the light from the middle and uppermost point of the mercurial column as seen in fig. 5 ; the reading is then taken by means of the scale on the limb and the vernier. In observing, the eye should be placed in a right line with the fore and back edges of the lower termination or edge of the vernier. A small white reflector placed behind the barometer will assist in throwing the light through the brass frame and the glass tube ; and the observer's vision may be further assisted by the use of a magnifying lens. The great object in standard barometers, is to obtain exact readings, which can only be done by having the eye, the front of the zero edge of the vernier, the top of the mercurial column, and the back of the vernier, in the same horizontal plane. To remove the Instrument. If it should be necessary to remove the barometer, first, by means of the adjusting screw (s), fig. 2, drive the mercury to the top of the tube, turning the screw gently when the mercury approaches the top, and stop turning directly any resistance is experienced ; next remove the instrument from the bracket, slowly invert it, and in carrying keep the cistern end uppermost. 3. The Barometer Vernier. The Vernier, an invaluable contrivance for measuring small spaces, was invented by Peter Vernier, about the year 1630. The barometer scale is divided into inches and tenths. The vernier enables us to accurately sub-divide the tenths into hundredths, and, even to thousandths of an inch. It consists of a short scale made to pass along the graduated fixed scale by a sliding or rack-and-pinion adjustment. The scales of standard barometers are usually divided into half-tenths, or 05, of an inch, as represented, in fig 6, by AB. The vernier, C D, is made equal in length to twenty-four of these divisions, and divided into twenty-five equal parts ; consequently one space on the scale is larger than one on the vernier, by the twenty-fifth part of *05, which is '002 inch, so that such a vernier shows FIG 5. 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. r/H c h a differences of "002 inch. The vernier of the figure reading upwards, the lower edge, D, will denote the top of the mercurial column ; and is the zero of the vernier scale. In fig. 6, the zero being in line exactly with 29 inches and five- tenths of the fixed scale, the barometer reading would be 29*500 inches. It will be seen that the vernier line, a, falls short of ^ a division of the scale by, as we have ex- plained, -002 inch ; 6, by '004 ; c, by '006 ; d, by "008 ; and the next line by one hun- dredth. If, then, the vernier be moved so as to make a coincide with z, on the scale, it will have moved through '002 inch ; and if 1 on the vernier be moved into line with y on the scale, the space measured will be 1 010. Thus, the figures 1, 2, 3, 4, 5 on the vernier measure hundredths, and the intermediate lines even thousandths of an inch. In fig 6*, the zero of the vernier is between 29'65 and 2970 on the scale. Passing the eye up the vernier and scale, the second line above 3 is perceived to lie evenly with a line of the scale. This gives '03 and '004 to add to 29*65, so that the actual reading is 29'684 inches. For the ordinary purposes of the 30 B FIG 6. barometer as a " weather glass," such minute measurement is not required. In household and marine barometers, the scale is only divided to tenths, and the vernier constructed to measure hundredths of an inch. This is done by making the vernier either 9 _gj ^S _ Ol 20 '1 5 10 OS 00 - - - - - 29 - - D - -- HE - FIG 6*. or ll-10ths of an inch long, and dividing it into ten equal parts. The lines above the zero line are then numbered from 1 to 10 ; sometimes the alternate divisions only are numbered, the intermediate numbers being very readily inferred. Hence, if the first line of the vernier agrees with 1 on the scale, the next must be out one-tenth of a tenth, or '01 of an inch from agreement with next scale line ; the following vernier line must be "02 out, and so on. Conse- quently, when the vernier is set to the mercurial column, the difference shown by the vernier from the tenth on the scale is the hundredths to be added to the inches and tenths of the scale. Price, Standard Barometer (fig 2) 880 Ditto, with English and Millimetre Scales 990 10 10 Ditto, with Tube 0'45-inch internal diameter . 12 12 NEGEETTI AND ZAMBEA, HOLBORN VIADUCT, E.G. m FIG. 9. FIG. 7. FIG. 8. 4. Large Standard Barometers with attached Thermometer suited for Observatories and Public Institutions. The tubes are T 6 oths internal diameter, and the bulbs of the thermometers are of the same dimensions. Price, Fig. 7. 21 5. Observatory Standard Barometers with extra large tube and cistern, arranged for observations being taken by the Cathetometer for extreme precision, as used at the Greenwich and Kew Observatories. Price, Barometer, Fig. 8, , 25 30 Cathetometer, Fig. 9 ... 35 45, CORNHILL, E.G., AND 122, BEGENT STREET, W., LONDON. FIG. 10. FIG. 11. 6. Cathetometer,^ (fig. 10.) Improved arrangement, suited for Observing Stations of the First Class. Price 50 to 80 ; varying with the fineness and accuracy of the divisions and the number of adjustments attached to the instrument. 10 NEGEETTI AND ZAMBEA, HOLBOEN VIADUCT, E.G., 7. Observatory Standard Barometer, fig. 11, of the highest class suitably mounted, for being read off with the Cathetometer, with a tube of exceedingly large internal diameter, the cistern also being of very large area especially arranged for taking observations with the most extreme precision. Our woodcut shows the Barometer to be without any scale, the readings being obtained by observing the level of the mercury in the tubes and the upper point of the cistern index, (or zero screw) through the telescope of the Cathetometer. Price, as fig. 11, 50 to 70 8. The Cathetometer, shown in fig. 9, is used for ascertaining with the utmost accuracy the space or distance between any two points. A brass rod or cylinder is firmly supported on a heavy base having three arms, each arm furnished with adjusting screws for setting the upright rod truly vertical. This rod is accurately divided throughout its length, and so arranged that it will revolve horizontally. Exactly at right angles to this scale and attached to it is a framework carrying a small Achromatic Telescope furnished with fine wire or spider lines in the eye-piece. This telescope is mounted with levels, having coarse and fine adjustments with clamps, &c., much' in the same manner as a Theodolite Telescope. The distance between the points to be ascertained is observed through the telescope, which can be moved with its adjustments vertically up or down upon the divided scale and its indications read off by means of verniers, which sub-divide the scale to the five-hundredth or one-thousandth part of an inch. The Cathetometer scale may be divided either in English inches or Centimetres and Millimetres as desired. Price of Cathetometer, as fig. 9, 35 9. Glass Cases for Standard Barometers of polished ebonized wood with plate glass sides and door with secure fastenings for the exclusion of dust and preserving the instrument from injury. .Price 5 5 to 10 10 10. Testing Chamber with double-action Air Pump for testing Standard Barometers, as used at the Kew Observatory. 70 11. Negretti and Zambra's Mountain Barometer (fig. 12), on Fortin's principle, is more portable, and less liable to derangement than ordinary mountain barometers. The arrangement of the flexible leather cistern is so simple that should the mercury become oxidized, it can be quickly removed, cleaned, and returned to the cistern without fear of affecting the correctness of the indications. The vernier reads to '002 of an inch, and the whole 45, CORNHILL, E.G., AND 122, EEGENT STEEET, W., LONDON. 11 FIG. FIG. 14. instrument is arranged in the most compact and convenient form for safety in travelling, and obtaining very accurate altitude measurements. Price, Including Brass Tripod Stand (as fig. 12) and Travelling Case for the Barometer, with English or Millimetre Scale 10 10 12. Standard Mountain Barometer of simpler form and smaller tube. Price 8 8 13. Standard Syphon Barometer (Gay Lussac's), divided on the glass tube, suited for Laboratory use (fig. 13), mounted on mahogany board, with thermometer and two verniers. Price 550 14. Standard Syphon Tube Mountain Barometer (Gay Lussac's), with attached thermometer, and improvement in the tube for excluding air. This is shown in fig. 14, and known as Gay Lussao's Air Trap : its use being to arrest any air that may pass up between the glass and the mercury. The bubbles of air are stopped and collected at the shoulder of the trap at K, and cannot possibly get up into the tube. This barometer is light and convenient for travelling. The graduations are upon the brass tube with verniers at each extremity reading from the centre. By adding the two readings together the correct height of column is obtained to -g^th f an inch. Price of Barometer, in leather travelling case, with Brass Tripod Stand (fig. 15) 880 This Syphon Barometer does not require correction for either capillarity or capacity, as each surface of the mercury is equally depressed by capillary attraction, and the quantity of mercury which falls from the long limb of the tube occupies the same length in the short one. The barometric height must, however, be cor- rected for temperature, as in the cistern barometer. 15. Board of Trade Standard or Kew Marine Barometer, bronzed brass frame, with iron cistern, and mounted on mahogany board, as in fig. 16. The graduations on the scale are so arranged that the exact reading can be obtained at once, without any previous adjustment of the level of the mercury in the cistern, as in the Fortin barometer. Price 550 16. Meteorological Offi.ee Station Barometer, Bronzed metal frame, with iron cistern and glass scales mounted on mahogany board. Exact readings can be taken without any previous adjust- ment of the mercury, fig. 17. Price, 770 17. Board of Trade Marine Barometer, similar to No. 16, but mounted on arm, with gymbal ring, instead of a mahogany board. Price, Packed in travelling case .440 12 NEGEETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., 18. FitzRoy's Marine Gun Barometer, constructed by Messrs. Negretti & Zambra under the immediate superintendence, and named by permission of, the Admiral for the special use of Her Majesty's navy, mounted with vulcanised India-rubber packing to prevent concussion and breakage caused by gun-firing. Packed in case 5 10 Extra tube for ditto 1150 See also Section Marine Barometers. Trials of the FitzRoy Marine Barometer under Fire of Guns. Some of the first baro- meters made by Messrs. Negretti and Zanibra on Admiral FitzRoy's principle were severely tried under the heaviest naval gun firing, on board H. M.S. Excellent', and under all the circumstances they withstood the concussion. The purpose of the trials was " to ascertain whether the vulcanised India-rubber packing round the glass tube of a new marine "barometer did check the vibration caused by firing, and whether guns might be fired close to these instruments without causing injury to them." In the first and second series of experiments, a marine barometer on Admiral FitzRoy's plan was tried against a marine barometer on the Kew principle, both instruments being new, ani treated in all respects similarly. They were " hung over the gun, under the gun, and by the side of the gun, the latter both inside and outside a bulkhead ; in fact, in all ways that they would be tried in action with the bulkheads cleared away." The result was that the Kew barometer was broken and rendered useless, while the new pattern barometer was not injured in the least. In a third series of experiments, Mr. Negretti being present, five of the new pattern barometers were subjected to the concussion produced by firing a 63-pounder gun with shot, and IGlbs. charge of powder. They were suspended from a beam immediately under the gun, then from a beam immediately over the gun, and finally they were suspended by the arm to the bulkhead, at the distance of only 3ft. 6in from the axis of the gun ; and the result was, according to the official report, "that all these barometers, however suspended, would stand, without the slightest injury, the most severe concussion that they would ever be likely to experience in any sea-going man-of-war." These trials were conducted under the superintendence of Captain Hewlett, C.B., and the guns were fired in the course of his usual instructions. His reports to Admiral FitzRoy, giving all the particulars of the trials* are published in the " Ninth number of Meteorological Papers," issued by the Board of Trade.* * With reference to these barometers, we have received the subjoined testimonial, with permission to use as we please. " Meteorologic Office, June 12th, 1863. " MESSRS. NEGRETTI AND ZAMBRA, " The barometers which you have lately supplied to Her Majesty's ships through this Office are much approved, being good for general service, afloat or on land. "(Signed) R. FITZROY." Admiral FitzRoy writes : " This marine barometer, for Her Majesty's service, is adapted to general purposes. " It differs from barometers hitherto made in points of details, rather than principle : 1. The glass tube is packed with vulcanised India-rubber, which checks vibration from con- cussion, but does not hold it rigidly, or prevent expansion. 2. It does not oscillate (or pump), though extremely sensitive. 3. The scale is porcelain, very legible, and not liable to change. 4. There is no iron anywhere (to rust*). 5. Every part can be unscrewed, examined, or cleaned, by any careful person. " These barometers are graduated to hundredths, and they will be found accurate to that degree, namely, the second decimal of an inch." 19. Negretti & Zambra's Short Tube Barometer, specially constructed by N". & Z. for Balloon experiments, Altitude Measurements, or for use at elevated mountain stations. p r i ce 770 45, COENHILL, E.G., AND 122, REGENT STREET, W., LONDON. 13 FIG. 15. FIG. 16. FIG. 12. 20. Negretti and Zambra's Students' Standard Barometer. In laying off and dividing the scale of this instrument, allowances have been made to compensate for the ordinary rise and fall of the mercury, making it sufficiently accurate for observers who do not wish to incur the expense of Fortin's arrangement for adjusting to a Zero Point. Fig. 16. Price 550 14 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.C. 21. Magnifying the Barometer Eange. The limit within which the barometric column oscillates, does not exceed four inches for extreme raDge, while the ordinary range is confined to about two inches ; and it has often been felt that the utility of the instrument would be much enhanced if by any means the scale indications could be increased in length. This object has been sought to be obtained by bend- ing the upper part of the tube from the vertical, so that the inches on the scale could be increased in length. Such an instrument was invented by Sir S. Moreland, in 1772, and named by him " the Diagonal Barometer." Another variation of Barometer, invented by M. Cassini, and improved by M. J. Benoulli, about the same date, was constructed with the upper part of the tube expanded into a large Bulb, and the lower part of the tube giving the scale is very much contracted in the bore, and bent at a right angle. From this the instru- ment was termed the Horizontal Rectangular Barometer. The upper part of the Barometer tube has also been forme d into a Spiral, with the scale placed along it, which is thus greatly enlarged. Another form of Extended Range Barometer was in- vented and made by M. Amontons in 1695, and named by him the Pendent Barometer. It is a Mercurial Barometer, the upper half of the tube (the indicating portion) being of smaller internal diameter than the lower half. By this arrangement, an extended range of scale is obtained. The lower end of this tube is open, and the mercury supported in it at varying distances by the upward pressure of the atmosphere, very similar in action to that of Howson's Barometer. Like the previously described instruments, this Barometer can only be regarded as a scientific curiosity, and is very subject to become out of adjustment in transit. This is unfortunate, as these Barometers are curiously sensitive, or perhaps we should more properly say, the movements of the mercury are rendered more visible. These methods of enlargement Barometer indications are not so convenient as Dr. Hook's elegant arrangement em- ployed in the ordinary Dial or Wheel Barometer. Therefore they are now very little used, and are of very little practical utility. FIG. 18. 45, COENHILL, E.G., AND 122, EEGENT STEEET, W., LONDON. 15 FIG. 18*. 22. Negretti and Zambra's Howson's Patent Long Range Barometer. " The object of this instrument is to add to the sensitive- ness of the ordinary mercurial column, by giving it an increased range, a desideratum which it appears to accomplish with simplicity and efficiency. " The principle of construction -will be understood on refer- ence to the diagram, fig. 18, which represents a section of the working parts of the barometer divested of its case. " A is the barometer tube, which is of large dimensions, and of greater length than usual in proportion to the additional length of range which it is intended to apply to it. The cistern, B, is of a tubular shape, so as to contain a fixed depth of mercury, also determinable by the range. To the bottom of this cistern is attached, concentrically, a light glass stem or long hollow tube, S, hermetically sealed, springing to a height of about 28 inches above the fixed level of the mercury in the cistern. " When all the parts are in situ, as in the diagram, fig 18*, the tube A being freely suspended, and the whole filled with the requisite quantity of mercury, the immediate result of the arrange- ment is that the cistern hangs in suspension without any fixed support. The stem C, it will be observed, passes up the tube A, and terminates a little below the upper level of the mercury M : its upper end is therefore exposed to no more downward pressure than that caused by the weight of the mercury above it, and consequently there is an excess of upward pressure from the atmosphere exteriorly which tends to raise the cistern. " If we suppose, for instance, the area of the stem to be half a square inch, and its top to be covered with 1 inch in depth of mercury (the space above being of course a vacuum), there will be a pressure tending to push the cistern downwards of only J Ib. or thereabouts, while the atmosphere will be pressing upwards on an equal area with a force of 7 Ibs. or more. Thus it will be seen that when the excess of upward pressure is exactly balanced by the weight of the cistern with its stem, and contained mercury up to the level &, an equilibrium will be established which will keep the cistern stationary. If from any cause the cistern should become lighter, it will ascend : if it should become heavier, it will descend, and the extent to which it will move in either case will be limited by the immer- 16 NEGEETTC AND ZAMBEA, HOLEOBN VIADUCT, B.C., sion or emersion of the tube A, or rather of the glass which bounds it. This is precisely the action which takes place under the influence of the fluctuations of atmospheric pressure. For, let the internal area of the tube A be supposed to be 1 square inch, and let a barometric rise take place equal to 1 inch by the ordinary standard, it is evident that a cubic inch of mercury will under these conditions leave the cistern, pass into the tube, and accumulate above the top of the stem : consequently the cistern, being relieved of a portion of its weight, will be pushed upwards until the cubic inch is replaced by the immersion of the glass of the tube A. As soon as this point has been reached it will become stationary ; but in the meantime, in the act of rising, it will have pushed up the entire column before it ; so that the total rise of the top of the column will be compounded of two motions, viz., of the ordinary barometric rise, and the rise of the cistern. The converse of this takes place on the occurrence of a diminution of atmospheric pressure. When the column moves, the cistern follows it, and when the cistern moves, it drags the entire column with it. " The instrument has been in use for many years, and its movements have been found to follow with accuracy those of the best standard Barometers. Its sensitiveness and activity during storms is conspicuous. There is also another advantage which this construction confers, viz., that the cistern is self-adjusting with regard to its level. Readings may be taken to three places of decimals without a vernier, and without any adjustment for variation of level in the cistern. At the same time, the error due to temperature is of an almost in- appreciable amount." * Price, in Ornamental carved Oak Case as fig. 18*. 14 14 23. McNield's Long Range Barometer. A barometer designed on a directly opposite principle to the one just described. The tube is made to float on the mercury in the cistern. It is filled with mercury, inverted in the usual manner, then allowed to float, being held vertically by glass points or guides. By this contrivance, the ordinary range of the barometer is greatly increased. As the mercury falls in the tube with a decrease of pressure, the surface of the mer- cury in the cistern rises, and the floating tube rises also, which causes an additional descent in the column, as shown by graduations on the tube. With an increase of pressure, mercury will leave the cistern and rise in the tube, while the tube itself will fall, and so cause an additional ascent of mercury. Price, 12 12 Both Howson's and McNield's Barometers are constructed by Negretti and Zambra with scales of from five to eight times that of the ordinary standard. Their sensitiveness is consequently increased in an equal proportion, and they have the additional advantage of not being affected by differences of level in the cistern. * Extract from the Proceedings of the .British Meteorological Society, Nov. 20th, 1861. Vol. i. p. 81. NEGRETTI AND ZAMBRA, HOLBOEN VIADUCT, E.G. 16 A Negretti and Zambra's Self -compensating Standard Barometer consists of the usual form of standard instrument, but attached to the vernier is a double rack moved by one pinion, so that when adjusting the vernier in one position, the second rack moves in the opposite direction, carrying along with it a plunger (the exact size of the internal diameter of the tube) dipping in the cistern, so that whatever displacement has taken place in the cistern, owing to the rise or fall of the mercury, it is exactly compensated by the plunger being more or less immersed in the mercury, consequently no capacity correction is required. Price, 18 18 Standard Barometer, with Electrical Adjustment. This barometer consists of an upright glass tube dipping into a glass cistern of mercury, so contrived, that an up-and-down movement, by means of a screw, can be imparted to it. Through the top of the tube a piece of platinum wire is passed and her. metically sealed. The cistern also has a metallic connection, so that by means of copper wires (in the back of the frame) a galvanic circuit is established ; another connection also exists by means of a metallic point dipping into the cistern. The circuit, however, can be cut off from this by means of a switch placed about midway up the frame. On one side of the tube is placed a scale of inches ; with a small circular vernier, divided into 100 parts, connected with the dipping point, and working at right angles with this scale. Eor taking an observation, a galvanic battery is connected by two binding screws at the bottom of the frame. The switch is turned upwards, thereby disconnecting the dipping point ; the cistern is then screwed up, so that the mercury in the tube is brought into contact with the platinum wire at the top ; the instant this is effected a magnetic needle arranged as a galvanometer on the barometer board will be deflected. The switch is now turned down ; by so doing the connection with the upper platinum wire is cut off, and established between the dipping point carrying the circular vernier and the bottom of the cistern ; the point is now screwed by means of the milled head until the needle is again deflected, and the line on the vernier cutting the division on the scale is the exact reading of the barometer. Price, 18 18 The two Barometers above-mentioned were exhibited 1y Negretti and Zambra at the Meeting of the Royal Meteorological Society, March, 1886. 45, CORNHILL, E.G., AND 122, BEQENT STREET, W., LONDON. 17 24. The Water Barometer first constructed by Professor Daniell of King's College for the Royal Society in 1830 was fitted up under his superintendence at their rooms in Somerset House. It consisted of a glass tube 40 feet in length and about one inch in diameter. This barometer was in action at Somerset House for some two years, and a series of observations made with it showed " that the Water Barometer preceded by one hour the indications of a mercurial instrument having a column of mercury of f inch diameter." On the removal of the Royal Society from Somerset House this Water Barometer was taken down by Messrs. Negretti and Zambra, refilled, and mounted by them at the Crystal Palace, Sydenham, where for a short time it excited considerable interest, but owing to various causes the indications were found to be incorrect scientifically. Eventually the instrument was destroyed by fire during the winter of 1866. At the suggestion of Dr. D. Price another Water Barometer was erected by Mr. Jordan for the Crystal Palace Company ; but although the Water Barometer is of great interest as a weather glass, its indications were again found to be of but little scientific value, owing to the effect of varying temperature on the aqueous vapour above the column of water. This difficulty led to the substitution by Mr. Jordan of glycerine for water, and the construction of the now well-known Jordan Glycerine Barometer, one of which is erected at the Times office and one also at the Kew Observatory by a grant from the Royal Society. Mr*. Whipple, the director at Kew, states the records obtained by it are fairly satisfactory. The tube of the Glycerine Barometer is composed chiefly of ordinary com- position gas tubing of f inch internal diameter : to this is very carefully joined and cemented about four feet of glass tube one inch internal diameter. The upper end of this tube is formed into a funnel-shaped cup, having a conical shaped stopper of India-rubber arranged for conveniently filling and adjusting the instrument. The glass portion of the tube is the indicating part of the barometer. Suitable divided scales are placed at the sides of the glass portion of the tube, one showing inches and tenths of absolute measure, and on the opposite side another scale of equivalent values of a column of mercury at a temperature of 60 Fahrenheit. R. H. Scott, Esq., of the Royal Meteorological Society, writes that during the continuance of a violent gale and storm, " a fall of more than 16 inches of glycerine has been noted." "The movements of the glycerine column are 10' 76 times greater than those of the mercurial column at the standard tem- perature, 333*57 inches of glycerine being equivalent to 31 inches of the mercurial barometer." We are chiefly indebted for these details of the Glycerine Barometer to Mr. Jordan's Pamphlet,* to which we refer our readers for further- particulars as to the construction and use of the instrument. * The Glycerine Barometer with Plate and Table of Corrections for Temperature, by James B. Jordan^ Mining Record Office Museum of Practical Geology. Price, One Shilling. C 18 KEGRETTI AND ZAMJ'.KA, HOLBORN VIADUCT, E.G., It will be seen that owing to the great length of the tube, viz., 27 feet, Jordan's Barometer can only be fitted up in very few buildings. To gain the advantage of so extended a range of scale in a convenient sized instrument, Messrs. Negretti and Zambra have constructed their NEW LONG RANGE MERCURIAL AND GLYCERINE BAROMETER, .28 B -31 24*. The Long Range or Open Scale Barometer is shown in section in fig. 19. It consists of a glass tube of the syphon form ; one side of the syphon, A, or closed end, being about 33| inches long, and the other only a few inches in length. To this short end is joined a length of glass tubing, B, of a much smaller (internal) diameter ; both tubes are of equal length, the smaller one being open at the top. The large ||_2|| tube, A, is filled with Mercury, and the small tube, B, partly filled with Glycerine, a fluid many times lighter in specific gravity than Mercury ; the rising and falling of the mer- curial column in the large tube having a lighter fluid to balance, and that dispersed over a larger space by reason of the difference in the diameter of the two tubes, a longer range is obtained, due loth to the unequal capacity of the tivo tubes and the difference in the specific gravity of Mercury and Glycerine. The range of these barometers is from six to ten inches to the inch of the ordinary Mercurial Barometer, yi^ of an inch can easily be observed without the use of a vernier. It is a most interesting instrument, as from the extremely extended scale the slightest variation is plainly visible. The actual size and form is about that of an ordinary Barometer, as seen in fig. 20 ; extreme length about 40 inches. FAIR FIG. 20. FIG. 19. Price, as fig. 20 ... Do., with Portable Stop Cock 5 5 5 10 45, CORNHILL, B.C., AND 122, KEGENT STREET, W., LONDON. 19 SELF-REGISTERING BAROMETERS. For many years a good and accurate self-recording barometer was much desired. This want is now satisfactorily supplied, not by one, but by several descriptions of apparatus. The first was the design of Admiral Sir A. Milne, who himself constructed, in 1857, we believe, the original instrument, which he used with much success. 25. Negretti and Zamtora's improved Self- Registering Mercurial Barometer or Baro- graph. In this instrument the various parts of the mechanism have been so modified and arranged that the record on the papers is obtained with the greatest precision and delicacy. The engraving (fig. 21) will give the general details. It should, however, be mentioned, that it is not a picture of the outward appearance of the instrument. The position of the barometer should be behind the clock ; it is represented on one side merely for the purpose of clearly illustrating the arrangement. The instrument has a large syphon barometer tube, in which the mercurial column is represented. On the mercury at A, floats a glass weight, attached to a silk cord, the other end of which is connected to the top of the arched head on the short arm of a lever-beam. The long arm of this beam is twice the length of the short arm, for the following reason. As the mercury falls in the long limb, it rises through an equal space in the short limb of .the tube, and vice versa. But the barometric column is the difference of height of the mercury in the two limbs ; hence the rise or fall of the float through half-an-inch will correspond to a decrease FIG. 21. or an increase of the barometric column of one inch. In order, then, to record truly the movements of the mercurial column, and not those of the float, the arm of the beam connected with the float is only half the radius of the other arm. From the top of the large arched head a piece of watch-chain descends, and is attached to the marker, B, which properly counterpoises the float, A, and is capable of easy movement along a groove in a brass bar, so as to indicate the barometric height on an ivory scale, C, fixed on the same vertical framing. On the opposite side of the marker, J?, is a metallic point, which faces the registration sheet and is nearly in 20 NEGEETTI AND ZAMBEA, HOLBOBN VIADUCT, E.G., contact with it. The framing, which carries the scale and marker, is an arrangement of brass bars, delicately adjusted and controlled by springs, so as to permit of a quick horizontal motion being communicated to it by the action of the hammer, E, of the clock, whereby the point of the marker is caused to impress a dot upon the paper. The same clock gives rotation to the cylinder, D, upon which is mounted the registering paper. The clock must be re- wound when a fresh paper is attached to the cylinder, which may be daily, weekly, or monthly, according to construction ; and the series of dots impressed upon the paper shows the height of the barometric column every hour by day and night. The space traversed by the marker is precisely equal to the range of the barometric column. Price, in an Ornamental Oak Case, fig. 21 18 18 and 22 26. King's Self - Registering Barometer. Mr. Alfred King, Engineer of the Liverpool Gas-Light Company, designed, in 1854, a barometer to register, by a continuous pencil- tracing, the varia- tions in the weight of the atmosphere ; and a highly-satisfactory instrument, on his principle, and constructed under his immediate superintendence, was erected at the Liverpool Observatory. Fig. 22 is a front elevation of this Barometer. A, the barometer tube, is three inches internal diameter, and it floats freely (not being fixed as usual) in the fixed cistern, B, guided by friction- wheels, W. The top end of the tube is fastened to a chain, which passes over a grooved wheel, turning on friction rollers. The other end of the chain supports the frame, D, which carries the tracing pencil. The frame is suitably weighted and guided, and faces the cylinder, C, around which the tracing paper is wrapped, and which rotates, once in twenty-four hours by a clock movement. For one inch change in the mercurial column the pencil is moved through five inches, so that the horizontal lines on the FIG. 22. 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 2T tracing, which are half an inch apart, represent one-tenth of an inch change in the barometer. The vertical lines are hour lines, and being nearly three- quarters of an inch apart, it will be seen that the smallest appreciable change in the barometer, and the time of its occurrence, are recorded. The barometer in this instrument is similar to Mr. McNeild's " Long-Range Barometer," described page 16. Constructed to order 280 to 300 THE ANEROID BAROMETER. 27. The Aneroid Barometer. The extremely ingenious instrument called the Aneroid, is no less remarkable for the scientific principles of its con- struction and action, than for the nicety of its mechanism. As its name implies, it is constructed " without fluid." It was invented by M. Vidi, of Paris. In the general form in which it is made it consists of a brass cylindrical case about five inches in diameter and two inches deep, faced with a dial graduated and marked similarly to the dial-plate of a " wheel-barometer," upon which the index or pointer shows the atmospheric pressure in inches and decimals in accordance with the mercurial barometer. Within the case, is placed a flat metal box made of German Silver, generally not more than half an inch deep and about two inches or a little more in diameter, from which nearly all the air is exhausted. The top and bottom of this box is corrugated in con- centric circles, so as to yield inwardly to external pressure, and return when it is removed. The pressure of the atmosphere continually changes, and with this varying pressure, the top and bottom of the box approach to and recede from each other by a small quantity ; but the bottom being fixed to the base, nearly all this motion takes place on the top. The top of the box is elastic, and rises and falls according as the compressing force lessens or increases. To the eye these expansions and contractions are not perceptible, so small is the motion. But they are rendered very evident by a delicate mechanical arrangement, communicating with a system of levers ; and, by the intervention of a piece of watch-chain and a fine spring passing round the arbour, turning the index to the right or left, according as the external pressure increases or decreases. Thus, when by increase of pressure the vacuum box is compressed, the mechanism transfers the movement to the index, and it moves to the right ; when the vacuum box expands under diminished pressure, the motion is reversed, and the index moves to the left. As the index traverses the dial, it shows upon the scale the pressure corresponding with a good mercurial barometer. The Aneroid being placed under the receiver of an air pump the scale is laid off to correspond with a Mercurial Barometer Gauge, and afterwards compared and corrected by a Standard instrument. 22 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., The engraving ("fig. 23) represents the latest improved mechanism of an aneroid. The outer casing and face of the instrument are removed, but the index hand is left attached to the arbour. A is the corrugated vacuum box which has been exhausted of air through the tube J, and hermetically sealed by soldering. B is a powerful curved spring, resting in gudgeons fixed on the base-plate, and attached to a socket be- hind, Fj in the top of the vacuum box. A lever, (7, joined to the stoub edge of the spring, is connected, by the bent lever at I), with the chain, .E7, the other end of which is coiled round, and fastened FIG 23. to the arbour, F. As the box, A, is com- pressed by the weight of the atmosphere increasing, the spring, J9, is tightened, the lever, (7, depressed, and the chain, E, uncoiled from F, which is thereby turned so that the hand, H, moves to the right. In the meanwhile the spiraj spring, G, coiled round F, and fixed at one extremity to the frame- work, and by the other to F, is compressed. When, therefore, the pressure decreases, A and B relax, by virtue of their elasticity ; E slackens, G unwinds, turning F, which carries the index hand, H, to the left. Near / is shown an iron pillar, cast as part of the stock of the spring, B. A screw works in this pillar through the bottom of the plate, by means of which the spring, J?, may be so adjusted to the box, A, as to set the index, H, to read on the scale in accordance with the indications of a Mercurial Barometer. In the higher class of aneroid baro- meters, the lever, C, is formed of a compound bar of brass and steel, so skilfully arranged as to perfectly compensate for the effects of extreme variations of temperature. The greatest perfection in Aneroids is now attained by having as perfect and dry a Vacuum as possible. Compensation being obtained by the compound metal bar previously mentioned. A Thermometer is sometimes attached to the Aneroid, as it is convenient for indicating the present temperature of the air, but for accuracy and safety from breakage, N. and Z. recommend the use of a separate Thermometer. Admiral FitzRoy, in his Barometer Manual, writes : " The Aneroid is quick in showing the variation of atmospheric pressure ; and to the navigator who knows the difficulty, at times, of using barometers, this instrument is a great boon, for it can be placed anywhere, quite out of harm's way, and is not affected by the ship's motion, although faithfully giving indication of increased or diminished pressure of air. In ascending or descending elevations, the hand or the Aneroid may be seen to move (like the hand of a watch), showing the 45, CORNHILL, E.C., AND 122, REGENT STREET, W., LONDON. 23 height above the level of the sea, or the difference of level between places of comparison." Aneroid barometers, if occasionally compared with a mercurial standard, are similar in their indications, and valuable ; but it must be remembered that for exact scientific observation, the Aneroid barometer cannot be put into comparison with the mercurial column for strict accuracy, although its con- venient size and great sensibility render it most useful for obtaining observations where a mercurial instrument is inconvenient to carry. Col. Sir H. James, R.E., in his Instructions for taking Meteorological Obser- vations, says of the Aneroid : " This is a most valuable instrument, it is ex- tremely portable. I have had one in use for upwards of ten years." One of the objects of Mr. Glaisher's experiments in balloons was "to compare the readings of an Aneroid barometer with those of a mercurial baro- meter." In the comparisons the readings of the mercurial barometer were corrected for index-error and temperature. Speaking of Aneroid indications,* Mr. Glaisher remarks : " A third (Aneroid) graduated down to five inches, and most carefully made and tested under the air- pump before use, read the same as the Mercurial Barometer throughout the high ascent to seven miles, September 5th, 1862.f I have taken this instrument up with me in every sub- sequent high ascent, and it has always read the same as the Mercurial Baro- meter. These experiments prove that an Aneroid can be made to read correctly at low pressures. " I may mention that on several occasions, Aneroid Barometers have been taken whose graduations have been too limited for the heights reached : these -p 24 have not broken or become * Travels in the Air. By F. Glaisher. Page 89. The Aneroid Barometer, f Wolverhampton to Cold Weston, near Ludlow, September 5th, 18G2. 24 NEGBETTI AND ZAMBEA, HOLBORN VIADTJCT, E.G., FIG. 25. FIG. 26. deranged by being subjected to a much less pressure than they were prepared for, but have resumed their readings on the pressure again coming within their graduations." The Aneroids used by Mr. Glaisher were made for him by Messrs. Negretti and Zambra. Directions for using the Aneroid. Aneroids are generally suspended with the dial vertical ; but if they be placed with the dial horizontal, the indications differ a few hundredths of an inch in the two positions. Therefore, if their indications are to be recorded, the instrument should be read off alivays in the same position. As before observed, the Aneroid will not answer for exact scientific pur- poses, as its error of indication changes slowly, and hence the necessity of its being set from time to time with the reading of a Standard Barometer. To allow of this being done, at the base of the outer case is a screw in connection with the spring attached to the vacuum box. By applying a small screw-driver to this screw, the spring of the vacuum box may be tightened or relaxed, and the index hand adjusted to the right or left on the dial, as in correcting a watch. 28. Pocket Aneroid Barometers. The patent for the Aneroid having expired, Admiral FitzRoy urged upon Messrs. Negretti and Zambra the desirability of reducing the size of the instrument as then made, as well as of improving its mechanical arrangement, and compensation for temperature. They accordingly at great expense, labour, and experiment, succeeded in reducing its dimensions to two inches in diameter, and an inch and a quarter thick. The exact size and appearance of these Aneroids is shown by fig. 24. For prices of Aneroid Barometers see page 29. 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 25 29. Watch Aneroid. Negretti and Zambra have still further reduced the size of the Aneroid to that of an ordinary watch, our engravings, figs. 25, 26 showing their exact size. By a beautifully simple contrivance, a milled rim is constructed to move round, and carry with it the index or pointer over the scale engraved on the dial, for the purpose of marking the reading, so that any increase or decrease of pressure may be readily seen. These very small instru- ments are found to act quite as correctly as the largest, and are much more convenient. Besides serving the purpose of a weather-glass in the house or away from home, if carried in the pocket, they are admirably suited to the exigencies of tourists and travellers. They may be had with scale sufficient to measure heights of 20,000 feet ; with a scale of elevation in feet, as well as of pressure in inches, engraved on the dial. The scale of elevation, which is for the temperature of 50, was computed by Professor Airy, late Astronomer Royal, who kindly presented it to Messrs. Negretti and Zambra, for publication.* Moderate- sized Aneroids, fitted in leather sling cases, are found very serviceable to pilots, fishermen, and for use in coasting and small vessels, where a mercurial barometer cannot be employed, because requiring too much space." Negretti and Zambra' s Watch-sized Aneroid Barometers, figs. 25 and 26, have now for many years been fully tried and tested, as ordinary Weather Indicators, for obtaining Altitude Measurements, and also for Mining purposes. From the very extensive patronage afforded to them by Government authorities (for Military and Naval service), Engineers, Surveyors, and Scientific Observers, &c., N. and Z. feel justified in giving their unqualified recommendation to these instruments, for Travellers' use, as being both accurate and convenient. 30. Our woodcuts, figs. 24, 25, 26, show form and actual size of the most useful Aneroid Barometers. Fig. 24 being our Pocket size. Fig. 25 our Watch size, with the simple Barometer Scale of inches and20ths of an inch. This same size instrument is manufactured with Altitude Scales ranging from 10 to 20 thousand feet. Fig. 26 is of similar size to the preceding, but has the Altitude Scale arranged to revolve, so that the zero or of this scale being set to the point occupied by the Index at the commencement of the ascent, the elevation attained above the starting point may be at once seen in a rough way on the scale. The divisions of this scale not being absolutely similar all round, causes an error in the reading, therefore, where exact observations are desired, the zero of the scale should be placed opposite to the 31 point, and the indications read off in the usual manner by inches and fractions, their value being known by reference to the Altitude Tables sent with the instrument, so that this form of Aneroid combines both methods of observing in one instrument. * See List of Books on Meteorology at end of this seotiou. 26 NEGRETTI AND ZAMBRA, HOLBOKN VIADUCT, E.G., FIG. 27. Our fig. 27 shows one of the most convenient arrangements yet introduced, viz., a Watch-sized Aneroid, with a reliable Thermometer and Compass. The hinged leather case containing the three instruments, being but little larger than an ordinary portemonnaie. Price, see page 29. 31. Measurement of Heights by the Aneroid. The dial of the Watch Aneroid for determining altitudes is engraved with two scales in concentric circles, the inner circle being divided into inches and tenths of an inch, corre- sponding with the scale of the Mercurial column of a Standard Barometer. The outer circle is divided into spaces representing 100 feet, each tenth division being numbered as 1,000, 2,000, &c. The zero point of this circle corresponds with 31 inches of the Barometer scale, for this reason, that the Barometer never rises so high as 31 inches, consequently, our scale of feet is always outside the weather range. The zero of the feet scale has nothing whatever to do with the sea-level, that is a variable point and must be determined at the time of observation either by actual measurement at half tide level, or by computation from a known height. 32. Measurement of Altitudes above Sea Level. In order to deter- mine the height of any station above the sea-level with this instrument, we must notice at what point it stands at the shore ; we then ascend, and on reaching the desired point, observe the position of the index on the dial. We then deduct the number of feet opposite the reading on starting from that against the reading at the elevated station, this gives the height above the level of the sea. Thus, if at sea-level, the barometer stands at 30 inches, and at the elevation it stands at 26 inches we get 900 feet, deducted from 4,800 feet, giving us a height of 3,900 feet, and so on for the other points of the scale. When great accuracy is required, simultaneous observations must be taken at the two stations to obviate any error that might arise from a change of weather between the times of observation. Further instructions for altitude measurement will be found in Negretti and Zambra's Treatise on Meteorological Instruments. 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 27 33. " Great storms are invariably preceded by a fall in the barometer of from '05 to '10 of an inch per hour. Storms from the eastward sometimes give loss local warning, but they are well foretold by the increase of statical force. Storms of a cyclonic character travel, it has been found, on an average about 20 miles an hour towards some point between NE. and SE., generally towards the former. They, therefore, take about twenty-four hours to traverse the British Isles, from the time of their commencement in the west of Ireland. The east coasts may thus be warned one day in advance by the telegraph ; and as the approach of a storm can be foreseen at the place threatened hours before its advent, notice v of gales may usually be given from one to two days in advance. As regards the exact time and locality, the prognostication of storms must necessarily present much difficulty. The forecaster must be guided in these respects rather by experience, to be gained by practice, than by princi- ples ; little information can be given without going into a complete examination of particular storms, each of which would present points of difference." Strachan'Si Weather Forecasts. NEGRETTI AND ZAMBRA'S SELF-RECORDING ANEROID BAROMETERS. FIG. 28. 34. This instrument registers automatically with ink upon a ruled paper chart attached to a vertical cylinder revolved for seven days by means of a Clock movement inside it. The fluctuations of atmospheric pressure act upon seven Aneroid vacuum chambers, connected by an exceedingly simple mechanical con- trivance to a long lever arm carrying the Pen, by which a magnified diagram is produced upon the paper on the cylinder of the rise or fall or present height of the Barometric column. These papers are ruled to represent inches and tenths of the Mercurial Barometer Scale. A small Thermometer is mounted upon the base of the instrument. Price, in a Glazed Cabinet, as shown in fig. 28 .'.7100 Kuled Papers, per Hundred, for above ... 18 NEGRETTI AND ZAMBRA'S SELF-RECORDING ANEROID BAROMETER. FIG. 29. 35. These Instruments are arranged to show the various fluctuations that have taken place in the Barometer during the absence of the observer. They consist of a carefully finished Aneroid, and an eight-day Clock ; between these is placed in a vertical position, a revolving cylinder having a metallic paper attached to it ruled to coincide with the inches and tenths of the barometer scale. Close to this paper, is a pencil mounted on a metallic rod and is moved up 'and down as the variation of atmospheric pressure acts upon the vacuum chamber of the Aneroid ; at every hour this pencil is made to mark the paper by simple mechanism in connection with the clock. By this means a black dotted curved line is produced on the paper, show- ing at a glance the present height of the barometer whether it is falling or rising for how long it has been doing so, and at what rate the change has taken place if falling or rising at the rate of one-tenth of an inch per hour, or one-tenth in twenty-four hours ; all of which are particulars most essential to know when foretelling the weather, and which can only be obtained from an ordinary barometer by very frequent and regular observations. Our engraving (fig. 29.) shows the full mounting of the Registering Aneroid, combining a reliable Timepiece with an exceeedingly interesting Meteorological Instrument, of a suitable and convenient size for a library or dining room mantel-shelf. Recording Aneroid Barometer with Thermometer, ag shown fig. 29 Price, 22 Large size ditto ditto with more Ornamental Mounting . 27 10 Haled charts for the above, per Hundred ...',. 110 PRICES OF NEGRETTI AND ZAMBRA'S 29 STANDARD ANEROID BAROMETERS. Compared and Corrected Scale Aneroid, Compensated for temperature, as supplied to the Royal Navy and Meteorological Department . . . . .-. . . . .550 Surveyors' or Engineers' Aneroid Barometer for Altitude Measurements, Compensated for temperature, with Revolving Ring, carrying Index, range of Scale, 10,000 feet, 4J inches diameter ...........770 Pull Range Engineers' Altitude and Surveying or Balloon Aneroid, corrected and Compensated for temperature, with 20,000 feet, Altitude scale (See engraving in Surveying Instru- ment Section) 880 Mining Surveyors' Aneroid Barometer, with a Scale reading to 7,000 feet above the Sea Level to 2,000 feet below . 5 10 Leather Case with Sling Strap, for any of the above . . 0126 Pocket-Sized Aneroid, with Revolving Ring carrying Index (size shown in fig. 24) . . . . . . . .440 Mountain Aneroid Barometer, Pocket-Size, for measuring Altitudes to 10,000 feet, Compensated for temperature 550 Ditto ditto ditto to 20,000 feet, fig. 24 . . .060 Watch-Sized Aneroid Barometer, of best Construction, Compensated for temperature, for Meteorological Observations or Altitude Measurements to 10,000 feet, (size shown in fig. 26) . . . . . . . .550 Watch-Sized Aneroid Barometer, to 20,000 feet . . .660 Watch-Sized Aneroid Barometer, with Devolving Altitude Scale for 10,000 or 20,000 feet (Seepage 25) . . 5 10 6 10- Watch-Sized Aneroid Barometers, with Thermometer and Compass, in Morocco Pocket Case (fig. 27.) . 7 70 and 880 Watch-Sized Aneroid Barometers in Solid Gold Cases 15 15 to 21 Ditto ditto in Stout Silver Cases . . 6 6 and 770 Aneroid Barometers may be had with the French Metrical Scale, or with the English and corresponding French Scale engraved on the same instrument. In the Section of our Catalogue " Household Barometers" will be found an illustrated price list of Aneroid Barometers in Ornamental Mountings, suited for the Drawing Room, Library or Hall, Ships or Yachts, &c. 80 NEGUETTI AND ZAMBBA, HOLBOKN VIADUCT, E.C., FIG. 30. 36. Recording Mercurial Barometer or Barograph for automatically recording the variations of atmospheric pressure by Photography. Recom- mended by the Meteorological Committee of the Royal Society, and used by many of the principal Meteorological Observatories. Fig. 30. exhibits the general arrangement of this Barograph. B is a Standard Mercurial Barometer mounted upon a mahogany board and table, lacing it is a Drum D, to which is attached the sensitised Photographic Paper. This cylinder is revolved once in 24 or 48 hours by the clock C. A Condensing Lens, E, projects the light from the Gas Burner G through the space F over the edge of the mercurial column, and thence to the photographic combination lens P, by which an image of the mercurial column is formed upon the sensitive paper on the drum for a regulated space of time. A screen or shutter L acted upon by the clock cuts off this image for the space of four minutes every two hours, leaving white lines upon the photographic paper representing intervals of two hours. At the side of the barometer tube are placed two zinc rods attached to the barometer board at the lower ends at A. These rods are con- nected at their upper ends with a delicate mechanical arrangement H and K, so contrived as to compensate for varying Thermometric changes in the mercurial column, these variations of temperature being also recorded upon the sensitive paper. Attached to the apparatus is, a glass cylinder, M, (of the same internal diameter as the Barometer tube), partly filled with mercury, into which is placed a sensitive Standard Thermometer for giving the temperature of the surround- ing air. B is an adjusting screw for regulating the height of the barometer upon its support. The apparatus when in action is enclosed in a light tight box. The Barograph is constructed to special older, the cost varying from Sixty to Seventy Guineas. 45, COEKHILL, E.G., AND 122, REGENT STEEET, W., LONDON. 31 INSTRUMENTS FOR ASCERTAINING THE TEMPERATURE OF THE AIR. THEEMOMETBES. FIG. 31. 37. Undoubtedly there is no instrument the use of which has so greatly increased in the past few years as the Thermometer : not only is it now essential to the scientific observer, the meteorologist, the physician, and the chemist; but both for domestic uses and manufacturing processes a really accurate thermometer is indispensable. The following is a list of the various forms of Standard Thermometers manufactured by Negretti and Zambra ; all of these, to ensure extreme accuracy, have their scales divided by the Prize Dividing Engine (fig. 31) to which was awarded a Prize Medal at the Great Exhibition of 1851, and is described in the Report of the Jurors as follows : " This is a beautifully contrived Divider on Ramsden's principle, with a long fine steel screw. The novelties are first, the wheel at the screw head, which is divided into 400 parts, and has cut upon its circumference (which is made broad) a helix screw, in the thread of which runs a detent, carried along by the run of the thread till it meets a stop clamped on the helix at a definite point. This arrests the screw at this point of the motion. A Prize Medal was awarded." Messrs. Negretti and Zambra supply Dividing Engines made on the above principle both for circular and straight line divisions. Price . . 35 to 150 NOTE. From Report of the Juries of the Exhibition of 1851. " Negretti and Zambra are the only exhibitors in the British portion who have sent Thermometers with their stem* graduated the only safe instruments for delicate experiments." 32 NEGRETTI AND ZAMBKA, HOLBORN VIADUCT, E.G., STANDARD THERMOMETERS. Two important improvements in the Tubes and Scales of Thermometers and Barometers, first introduced by Negretti and Zambra, have become so extensively used that N. and Z. deem a short notice necessary to secure to themselves the credit of the inventions. The first improvement is the introduction of a white Enamel at the back of Thermometer Tabes, which renders the mercury much more plainly visible both in large and small-bore tubes. Most of the extremely delicate Ther- mometers now in use would have been almost useless but for this enamelling. This invention has also been applied to the back of Barometer Tubes. The second invention is the use of Porcelain for Scales and Dials of Thermometers, Barometers, &c., in place of metal, ivory, or wood, all of which so soon become soiled and tarnished, and eventually the divisions and figures are obliterated by the action of the atmosphere, sea-water, or damp. The divisions and figures on these porcelain plates are etched in with fluoric acid, and the colour permanently burnt or melted in by fire. That these are important inventions may be inferred from their use in all thermometers and barometers supplied to the Board of Trade and other Government departments. 38. Independent Standard Thermometer (fig 32), with Negretti and Zambra's Enamelled tube, and Engine, divided into either Fahrenheit or Centigrade scales, the divisions engraved on its own stem and mounted on silvered brass, boxwood, or Negretti and Zambra's Patent Porcelain Scales. Price, 550 Kew Certificate for above Thermometer 050 39. Comparative Standard Thermometers (fig. 33). These Thermometers are made by comparison with great care, from an accurate standard, correct to T V f a degree. Engine-divided EnamelledTubes mounted on Silvered Brass or Negretti and Zambra's Patent Porcelain Scales, with Mahogany or Oak framing. Price, 220 and 2 10 FIG. 32. N. & Z's Standard Thermometers are made from selected tubes, the internal diameter of which is ascertained by very carefully conducted experiments. They rr T( -, oo 'J are also strictly tested for index error, and a copy of the corrections, if any, furnished with each instrument, if required. We recommend the Standard Thermometers not to be mounted in any way, but the tube to be enclosed in a strong outer glass jacket; the bulb dipping 45, COKNHILL, E.G., AND 122, BEGENT STREET, W., LONDON. 33 FIG. 34. 30- 70- 30- 40 FIG. 35. into a reservoir of mercury, and the whole hermetically sealed, as in our Standard Deep-sea Thermometers ; by these means the bulb is effectually protected from the pressure of the atmosphere, either from barometrical changes or difference in altitude, and the divisions on the stem are so covered by the outer glass tube that they cannot be effaced or become invisible. [ 40. Board of Trade Thermometer. It consists of a carefully compared thermometer with ISTegretti and Zambra's enamelled tube divided on its stem to degrees, which are sufficiently large to admit of sub-division into tenths of degrees and ranging from 0? to 130. The scale is of Negretti and Zambra's Patent Porcelain, having the figures etched upon it, and burnt in a permanent black. It is a reliable comparative or reference thermometer, adapted for almost any ordinary purpose, and cannot be injuriously affected by any chemical action arising from air or sea- water. (Fig. 34). This thermometer is employed in D NEGRETTI AND ZAMBEA, HOLBORN VIADUCT, E.G., the Royal Navy and for the observations made at sea for the Board of Trade and Meteorological Department. Price, in Neat Japanned Case 10 6 Ditto Copper Case 12 6 A set of 6 Ditto ditto, in Copper Cases, fitted in a Mahogany Box . 2 10 41. Thermometers of Extreme Sensitiveness. Negretti and Zambra's Instantaneous Thermometer, with Gridiron form of bulb, and divided upon the stem, as shown in the International Exhibition of 1862, used by Mr. Glaisher in his Balloon ascents to obtain very rapid thermometric readings. (Fig. 35) Price, 3 3 to 6 60 42. Thermometers, very delicate, with Spiral or Coiled bulbs, engine-divided upon the stem, mounted on boxwood, metal, or opal glass scales. Fig. 36. Price, 220 and 330 43. Earth Thermometer for ascertaining the tem- perature of the soil at various depths. The tube is about five feet long, enclosed in stout wood, protected and strengthened by metal mountings and a pointed cap. The scale is of Negretti and Zambra's Patent Porcelain with enamelled and burnt-in divisions and figures. Figs. 37 and 38. Price, 1 15 and 220 44. Earth Thermometers in series for inserting into the ground at depths of 6 inches, 12 inches, 24 inches, 48 inches and 120 inches. These thermometers are arranged with a scale about 6 inches above the earth. Price for the series 7 7 45. The temperature of the soil is a very important element in the consideration of climate especially in connection with the growth of vegetation. " It has been calculated by Mr. Raikes, from experiments made at Chat Moss, that the temperature of the soil when drained averages 10 higher than it does when undrained ; and this is not surprising when we find that lib. of water evaporated from 1,000 Ibs. of soil will depress the whole by 10, owing to the latent heat which it absorbs in its conversion into vapour." Faraday has calculated that the average amount of heat radiated in a day from the sun on each acre of earth in the latitude of London, is equivalent to that which would be produced from the combustion of thirteen thousand four hundred and forty pounds of coal. FIG. 38. " The extremes of temperature in the different climates of the FIG. 37. 45, COENHILL, E.G., AND 122, EEGENT STREET, W., LONDON. 35 earth are widely separated from each other, and the range of the thermometer is always greatest in the interior of the continents within the tropics. Mr Campbell, in the country of the Botchuanas, saw the thermometer at 8 a.m. at 28, and at 84 at noon. Mr. Bruce records a temperature at Gondar of 113. The thermometer at Benares rises to 118 ; at Sierra Leone the thermometer on the ground has been seen to rise to 138 P , and Humboldt gives many instances of the temperature of the torrid zone rising to 118, 120, and 129. At one time he found the temperature of a loose, coarse-grained granite, in the sun, 140'5. In the Dukhun at a height of 3,090 feet above the sea, Col. Sykes once saw the thermometer in the shade at 105, the range of the thermometer generally being from 93.9 to 40^.5." Slightly beneath the surface of the earth in the tropics, Humboldt states temperatures of 162 and 134 are frequently noted, and in white sand at Orinoco 140, whilst at the Cape of Good Hope under the soil of a bulb garden a temperature of 150 is recorded by Herschell. In China, the temperature of water of the fields was found to be by Meyer 113 and adjacent sand much hotter. These extremes of temperature, which would cause the specific gravity of the air to vary from 1167 to 863, may serve as a kind of measure of the dis- turbing causes which interfere with the velocity and local direction of atmos- pheric currents and other phenomena, the calculation of which has been founded upon mean results. DanielVs Meteorology. It is stated that below the layer of constant temperature (estimated at about 80 to 90 feet from the earth's surface), the temperature is found to increase one degree Centigrade for every 100 feet. 46. Earth Thermometer, Symons' Arrange- ment, with NEGUETTI & ZAMBBA'S Slow Action Thermometer. An iron tube closed at the lower end is forced down into the earth, and secured at the desired depth, and the thermometer lowered down into it by a cord or chain to the bottom, and allowed to remain a sufficient time ; when the temperature is to be noted, it is quickly drawn up and its indication observed. The great advantage of this method of obtaining Earth Temperatures is that the ther- mometer can at any time be compared with a Standard, which is a difficult if not almost impossible operation to be carried out with Thermometers of great length (fig 39). Also see fig. 49, page 42. Price, according to length, 110 150 1 10 0, 2 2 0. By means of these instruments it has been found that variations depending on the hour of the day are D2 FIG. 39. 36 NEGRETTI AND ZAMBKA, HOLBOEN VIADUCT, E.G., scarcely sensible at a depth of 2 or 3 feet, and that those which depend on the time of year decrease gradually as the depth increases, but still remain sensible at the depth of 25 feet, the range of temperature during a year at this depth being usually about 2 or 3 degrees Fahr. The mean rate of increase of temperature downwards is about 1 degree Fahr. for each 55 feet. SELF-REGISTERING THERMOMETERS FOR HEAT. Negretti and Zambra' s Patent Self-registering Maximum Thermometer. The only Instrument of the kind adapted for transmission to India and the Colonies. 47. Previous to the Great Exhibition of 1851, all persons interested in meteo- rological observations were constantly annoyed by the inconvenience arising from, the imperfect construction of Maximum Thermometers ; and although Messrs. Negretti and Zambra at that time exhibited one or two new forms of instru- ments, nothing new in principle was brought forward. A thermometer, old in principle, greatly improved by Negretti and Zambra, wherein a bubble of air caused a separation in the mercurial column to form an index, was exhibited by them ; but as the air bubble at different temperatures assumed different lengths it was not approved by the Jury appointed to examine Meteorological Instru- ments. The instruments invented by Dr. Rutherford and Six, as Maximum Thermometers, had both proved inefficient for the purposes required ; and although the best and most correct forms of these were also exhibited by Negretti and Zambra, they still saw that a great want would be met if a perfect instrument could be invented to indicate Maximum temperatures, all the above being imperfect Rutherford's from the tendency of the index to plunge in the mercury, Six's from the different expansive properties of the alcohol, mercury, &c., of which it is composed, and the one already alluded to, not only from the defects before noticed, but also from its liability to resolve itself into an ordinary thermometer when used, unless in the hands of a skilful manipulator. How far the New Patent Maximum Thermometer of Negretti and Zambra has supplied all these deficiencies may be judged from the fact that in all the principal Observatories throughout the world it is used, to the exclusion of all others, unless for the purposes of comparison. They are now in the hands of all our most scientific men, and have given universal satisfaction. The simplicity of their construction enables the most uninitiated in thermometers to use them with confidence and safety ; and another important feature in them is the impossibility of putting them out of order, for nothing short of actual breakage can in any way cause them to fail. 45, COBNHILL, E.G., AND 122, EEGENT STREET, W., LONDON. 37 FIG 40. 48. Negretti and Zambra's Patent Self-registering Standard Maximum Thermometer, consists of a tube of mercury mounted on an engraved scale, as shown in fig 40. The thermometer tube above the mercury is entirely free from air ; and at the point (A) in the bend above the ball, is inserted and fixed with the blow-pipe a small piece of solid glass, or enamel, which acts as a valve, allowing mercury to pass on one side of it when heat i s applied ; but not allowing it to return when the thermometer cools. When mercury has been once made to pass the valve, which nothing but heat can effect' and has risen in the tube, the upper end of the column registers the maximum temperature. To return the mercury to the btflb, we must apply a force equal to that which raised it in the tube ; the force employed is gravity, and is applied by simply lowering the bulb end of the thermometer, when the gravity of the mercury in the tube will be sufficient to unite it with that in the bulb, and thus prepare the instrument for future observation. Price, mounted with Negretti and Zambra's enamelled tube and Patent Porcelain or Opal glass Scale, fig. 40 110 The following is an extract from the Report of the Astronomer Royal, pub- lished shortly after the invention of the instrument it, however, applies more strongly now, inasmuch as the intervening years have fully proved the efficiency and value of this invention : - Report of the Astronomer Royal, May, 1852. " We have for several years baen very much troubled by the failures of the Maximum Self-Eegistermg Thermometers, especially those exposed to the sun: the part of the tube in which the index ought to slide becomes foul, apparently lined with* a coat of metal, and the index is immovable. A construction invented by Messrs. Negretti and Zambra appears likely to evade this difficulty. The mercury in its expansion is forced past an obstruction in the tube and does not return past in its contraction. No index is required in this construction. The specimens of this instrument which we have tried answer well." In the Quarterly Report of the Registrar General, about the same time, there is the following annotation : l * The form of instrument adopted during the past quarter for maximum temperature is that of Negretti and Zambra, which is found to act admirably." J. GLAISHEE, Esq., F.R.S., in his Lectures on the Results of the Great Exhibition, delivered at the Society of Arts, at the suggestion of his late Royal Highness the Prince Consort, when speaking of Meteorological Instruments (page 363) says : " In. maximum and minimum thermometers there was nothing new exhibited, although great need had long existed for an effective Maximum Thermometer. Thanks to the exhibition, however, this want has * The whole of Negretti and Zambra's Standard Thermometers have their improved enamelled back tabes and are Engine-divided on the stem. 38 NEGBETTI AND ZAMBHA, HOLBOEN VIADUCT, E.G., since been supplied. Messrs. Negretti and Zambra have invented a thermometer, the construction of which is as follows : a small piece of glass is inserted in the bend, near the bulb and within the tube, which it nearly fills : at an increase of temperature, the mercury passes this piece of glass ; but on a decrease of heat, not being able to recede, it remains in the tube, and thus indicates the maximum temperature. After reading, it is easily adjusted. Pour of these instruments I have had at work for upwards of a month, two in ordinary observations, and two subject to severe tests, and all have answered admirably. Hitherto every series of meteorological observations has been more or less broken by the frequent plunging of the steel index into the mercury, or becoming otherwise deranged. Messrs. Negretti and Zambra have, in their Maximum Thermometer, supplied a want long felt." * Extract from the Report of the Council of the British Meteorological Society, read at a General Annual Meeting of its Members, 1852 : " Negretti and Zambra's Thermometer, for the determination of maximum temperature, is "one of the good results of the Great National Exhibition, which proved itself, as regarded meteorological instruments, a most useful exponent of the insufficiency of those sold to the general public ; this Thermometer is the best which has yet been constructed for maximum temperatures, and particularly for sun observations ; for as the reading is determined by the entire mercurial column being detained at its highest point by a simple con- trivance within the tube, the necessity for an index is avoided, and with it the constant and distressing recurrence of derangement attendant upon the employment of those generally in use. This thermometer, constructed and brought into operation since the close of the Exhibition, has been for some time in the hands of Members of the Council, but only recently among its meteorological contributors, from its having been esteemed desirable that the Council should be well informed, by actual experiment, ot' the well-working of the instrument before sanctioning its general circulation. Accordingly, in the early part of the year, for some months several of Negretti and Zambra's Maximum Thermometers were subjected by our Secretary to severe tests, and as the results were highly satisfactory, the Council have not only viewed this instrument as an addition to the practical meteorologist, but strongly recommended its adoption and general use." Copj from the Report of the Kew Committee of the British Association 1853-4:- " The very ingenious instrument of Messrs. Negretti and Zambra has one quality, which, as regards durability, places it above every other form, of Maximum Thermometer, for when once well-constructed, it can never get out of order, the observer having first satisfied himself as to its correctness, may ever after- wards use it with confidence, relying that his register will not be interrupted by any of those annoyances to which he may have been accustomed in other forms of this instrument." From E. J. LOWE, Esq., F.R.A.S., F.G.S., &c., &c., to Messrs. NEGRETTI AND ZAMBRA. " GENTLEMEN, It affords me the greatest pleasure in being enabled to speak with praise regarding your Patent Maximum Thermometer. I have used a dozen of them for some time at both my observatories, and of these several since the date of their invention. In no single instance has there been any cause of complaint. Within the last few months I have carefully tested them in various ways, yet always with the most satisfactory results. I can therefore say with truth that your patent instrument is the best Self- Registering Maximum Thermometer which has ever passed through my hands; indeed, no observer can do without it." HlGHFIELD HOUSE OBSERVATORY, NEAR NOTTINGHAM. FIG. 41. 49. Negretti and Zambra's Patent Solar Radiation Thermometer (fig. 41). Consists of a mercurial thermometer with a blackened bulb, the * The thermometers have now been used with equal satisfaction for thirty-five years. 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. FIG. 42. scale is engine-divided on the stem, and the divisions protected by a glass shield. In use, it should be placed horizontally, with its bulb in the full rays of the sun, resting on grass, and, if possible, so that lateral winds should not strike the bulb. The directions for use are identical with those for the determining of the temperature of the air. Fig. No. 41. Price, 1 10 50. Vacuum Solar Radiation Thermometer (fig. 42). This instrument consists of Negretti and Zambra's blackened bulb Radiation Thermometer, enclosed in a glass tube and globe, from which all air is exhausted, as suggested by Sir John Herschel in the Admiralty Manual of Scientific Enquiry, in 1849. Thus protected from the loss of heat which would ensue if the bulb were exposed, its indications are from 20 to 30 higher than when placed side by side with a similar instrument with the bulb exposed to the passing air. At times when the air has been in rapid motion, the difference between the reading of a thermometer giving the true temperature of the air in the shade, and an ordinary solar radiation thermometer, has been 20 only, whilst the difference between the air temperature and the reading of a radiation thermometer in vacuo has been as large as 50. It is also found that the readings are almost identical at distances from the earth varying from six inches to eighteen inches. By the use of this improved Solar Radiator the amounts of solar radiation at different places are rendered comparable ; with the exposed bulb Thermometer, (fig. 41) the results could not be compared, as the bulbs of the thermometers would be under very different conditions as to exposure and currents of air. This new arrangement gives the readings very much more uniform, and is found to be a decided improvement. Price, 150 Instructions for use same as No. 48. FIG. 43, 40 NEGRETTI AND ZAMBRA, HOLBOEN YIADUCT. E.G., 51. Negretti and Zambra's Patent Registering Maximum Thermometer with either black or bright bulbs for experiments on radiant or reflected heat, the scale divided on the stem, mounted on a brass stand. Fig. 43. Price, 1 10 52. Negretti and Zambra's Improved Solar Radiation Vacuum Thermometer, with Mercurial Test Gauge. (Fig. 44.) For some many years most important investigations have been in progress in connection with Solar Heat, and as it is evident that all such inquiry should be carried out with the utmost precision, a question arose as to the perfection of the vacuum in different Solar Radiation Ther- mometers, and hence a ready means of testing these instruments became desirable for the purposes of comparison. Although this want had been repeatedly pointed out, no attempt had been made to remedy the defect. At last, we produced a Solar Radiation Thermometer with a small mercurial vacuum gauge inside the outer covering, which gives the exact amount of vacuum, or, it might more properly be called, the exact amount of air left in the space around the thermometer. The insertion of this small test gauge in the manner that it has been effected, is one of the most beautiful arrange- ments ever effected by the skill of the glass- blower. As a matter of course, having pointed out the road, other tests were devised. Among others, an electrical test, by inserting metal wires and connections in the two ends of the glass shield, by which a current of electricity from a Rhumkorf 's Induction Coil can be passed through the tube, and the colour, &c., &c., of the electric discharge be observed. This test has two defects, viz., that coils and batteries are not always available, and also that the metal connections in the glass tube are very liable to fracture, and consequent leakage of air into the tubes from the cracking of the glass around the wires. We need hardly observe that this is a most important invention and improvement, for, without satisfactory evidence of the perfection of the vacuum, strict experiment cannot be carried out. Price, 1 16 53. Wood Stand for Negretti and Zambra's Patent Vacuum Solar Radiation Thermometer, for experiments at four feet from the FIG. 44. 45, COBNH1LL, E.G., AND 122, REGENT STREET, W., LONDON. 41 FIG. 47. FIG. 46. FIG. 45. ground. Suggested and recommended by the Rev. F. W. Stow, who advises that the bulb end of the thermometer should be placed facing the S.E., and in such a manner that the air may circulate freely round it. Strict shade temperature should also be noted by a good Thermometer, so as to obtain the Maximum in sun and shade, and from these the amount of Solar Radiation may be deduced. Fig. 45. Price, 110 54. Fig. 46 shows a new arrangement of Negretti and Zambra's Patent Solar Radiation Maximum Thermometer in vacuo. It will be seen in the woodcut that the bulb of the Thermometer is exposed to the sky in a vertical position, with its stem enclosed by a light case or box. The scale is on the stem of the Thermometer, but, as in No. 57 the scale is figured the reverse of an ordinary instrument, the reading commencing from the end of the tube and not at the bulb. This arrangement has been introduced by N. and Z. to meet some requirements in connection with observations on solar temperatures where it has been supposed that a perfect sphere presented to the solar rays would give far more accurate indications than a projecting bulb such 'as seen in figs. 41 and 43. Fig. 46. Price, 1 15 55. Negretti and Zambra's Patent Registering Clinical Thermometers of various sizes and forms will be described in future sections with prices and illustrations. 56. Babinet's Apparatus, Sling Thermometer or Thermometer Fronde, for ascertaining the temperature of the Air by the rapid rotation of two sensitive Thermometers, Price with Thermometers. (Fig. 47.) 2 10s. 42 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, B.C.. 57. Negretti and Zambra's Patent Self-Registering Maximum Thermometer, for recording the Temperature of Mines, Thermal or Boiling Springs, Atmospheric or Earth Temperature, &c., &c. This Thermometer has its scale divided and figured upon the stem, the REVERSE of an ordinary Thermometer the reading commencing from the end of the tube and not at the bulb. The stem or tube is mounted in and protected by a stout glass shield, the bulb of the Thermometer being uppermost, and all mercury passing the bend or contraction in the tube will by gravity fall to the opposite end, and be detained and measured. The whole instrument is conveniently mounted in a round copper or brass case, with a handle or ring attached to the top for suspending the Thermometer. Fig. 48. FIG. 48. FIG. 49. In use, the Instrument is suspended by the ring attached to the top of the metal mounting, and as it enters a heated atmosphere the mercury in the bulb expands into the tube, passing the bend or contraction* near the bulb ; whatever quantity of mercury passes the bend will remain in the tube, and not recede when the temperature cools ; should thirty or forty degrees of mercury pass, it will of its own weight, fall to the end of the tube ; should it not do so, hold the Thermometer in an oblique position, the bulb end being lowest so that the mercury in the tube may very gradually descend until it touches any mercury at the bend,f if now the bulb end be raised the mercury will again descend carrying with it any small particles that have passed the bend- When the mercury has all been collected at the end of tube, read off in degrees on the thermometer scale its indication, and that will be the Maximum Temperature. To re-set the Thermometer hold it bulb downwards, and swing it back- wards and forwards, to force back the excess of mercury, beyond the present temperature, into the bulb. This precaution should always be observed before commencing to take an observation. Price, in Strong Metal Mountings. 1 10 57*. In our Section, " Thermometers for Special Purposes," will be found woodcuts of several other forms of these Instruments, with details as to their construction and use, and of fig. 49, for obtaining the temperature of Springs or Wells or Earth Temperatures, see also No. 46. * Sometimes a bend and sometimes a contraction is used to separate the indicating mercurial column, t The tube should not be held upright, or portions of the mercury may pass by the bend into the bulb. 45, CORNHILL, B.C., AND 122, REGENT STEEET, W., LONDON. The following extract from the Fourth Report of the Committee on Under- ground Temperature, British Association for Advancement of Science, 1871, will sufficiently prove the advantages of Negretti and Zambra's Patent Maximum Thermometer without further comment : - " The Thermometer which the Committee have been employing for the last three years is a Phillips's Maximum, having so fine a bore that the detached column of mercury which serves as the index is sustained in the vertical position by capillary action, and will bear a moderate amount of shaking without slipping down. Numerous instances, however, have occurred in which the index has slipped in consequence of jerks or concussions sustained by the thermometer in hauling it up from a depth. During the past six months the Secretary has been in correspondence with Messrs. Negretti and Zambra respecting a proposed modifi- cation of the Maximum Thermometer known by their name, which occurred to him more than a year ago, and was described by him privately to some meteorological friends at the last Meeting of the Association. It was then supposed to be new, but it now appears that Messrs. Negretti and Zambra have made something of the kind for the last fifteen years. Several changes, however, were necessary before the thermometer was adapted to the uses of the Committee, and the first complete instruments were received in June last. They are enclosed, like the thermometers previously used, in hermetically sealed tubes, for protection against pressure, and they have the advantages (1) of Icing able to bear severe jolts without derangement of their indications, and (2) of presenting to view a mucli broader column of mercury, so as to be more easily read in a dim light. 58. Mercurial Thermometer, with large Cup shaped Bulb, (fig. 50), convex on the one side and concave on the other, exposing a very large surface, suited for experiment on Radiant or Accumulated heat. Price, Engine-divided on the Stem 150 59. Negretti and Zambra's Patent Marine Maximum Thermometer, (fig. 48.) As all other marine thermometers are liable to give false indications from the movements of the vessel in rough weather, this instrument becomes a most important improvement. It is constructed and used in a similar manner to No 57, the bulb of the thermometer being uppermost; and no oscillation, however violent, can disturb the indications. It is mounted in a strong wood or metal frame, suitable for sea service. Price, 110 60. Helio-Pyrometer. Mr. T. Southall, of Birmingham, has published some very remarkable results obtained with a Standard Maximum Registering Thermometer, having a Blackened Bulb placed within a shallow box lined through- out with black velvet, and having a soft cushion of the same material in the bottom. Upon this cushion the Thermometer is to be placed, and covered over as closely as possible by a piece of plate glass. Thus arranged, Accumulated Sun Temperatures have been noted by FIG. 50. NEGEETTI AND ZAMERA, HOLBOEN YIADUCT, F.C., Mr. Southall varying from 216 to nearly 232 degrees of temperature. In fact Mr. S. states he has, with this apparatus, caused Water to loil rapidly by Solar Heat. Negretti and Zambra's Patent Maximum Thermometer will be found eminently suited for experiment with the Helio-Pyrometer, as there is no fear of the thermometer being spoilt by derangement of the index, as is the case with both Rutherford's and Phillips's instruments. Price of complete Apparatus with N. and Z.'s Patent Maximum Thermometer 220 Extract from the Report of the Council of the British Meteorological Society, read at a General Annual Meeting of its Members, 1852 : " Negretti and Zambra's Thermometer, for the determination of maximum temperature, is one of the good results of the great National Exhibition, which proved itself, as regarded meteorological instruments, a most useful exponent of the insufficiency of those sold to the general public ; this Thermometer is the best which has yet been constructed for Maximum temperature, and particularly for Sun observations. FIG. 51. FIG. 52. 61. Pyrheliometer (Pouillett's) (fig. 51), for ascertaining the effect of the sun's heat upon a given area by the number of degrees of heat imparted to mercury in five minutes. Price, 550 This instrument is composed of a shallow cylinder of steel, A, fig. 51, which is filled with mercury. Into the cylinder a thermometer, D, is introduced, the stem of which is protected by a piece of brass tubing. We thus obtain the temperature of the mercury. The flat end of the cylinder is to be turned towards the sun, and the surface, B, thus presented is coated with lamp black. 45, CORNHILL, E.G., AND 122, BEGENT STEEET, W., LONDON. 45 There is a collar and screw, C, by means of which the instrument may be attached to a stake driven into the ground, or into the snow, if the observations are made at considerable heights. It is necessary that the surface which receives the sun's rays should be perpendicular to the rays ; and this is secured by appending to the brass tube, which shields the stem of the thermometer, a disk, ^7, of the same diameter as the steel cylinder. When the shadow of the cylinder accurately covers the disc, we are sure that the rays fall, perpendicular, on the blackened surface of the cylinder. " The surface on which the sun's rays here fall is known ; the quantity of mercury within the cylinder is also known ; hence we can express the effect of the sun's heat upon a given area, by stating that it is competent, in five minutes, to raise so much mercury so many degrees in temperature." Dr. TyndaWs il Seat considered as a Mode of Motion" 62. JSthrioscope (Leslie's) (fig. 52.) The celebrated philosopher, Sir John Leslie, was the inventor of this instrument, the purpose of which is to give a comparative idea of the radiation proceeding from the surface of the earth towards the sky. It consists, as represented in fig. 52, of two glass bulbs united by a vertical glass tube, of so fine a bore that a little coloured liquid is supported in it by its own adhesion, there being air confined in each of the bulbs. The bulb, J., is enclosed in a highly polished brass sphere, D. The bulb, B, is blackened and placed in the centre of a metallic cup, C, which is well gilt on the inside, and which may be covered by a top, F. The brass coverings defend both bulbs from solar radiation, or any adventitious source of heat. When the top is on, the liquid remains at zero of the scale. On removing the top and presenting the instrument to a clear sky, either by night or by day, the bulb, B, is cooled by terrestrial radiation, while the bulb, A, retains the temperature of the air. The air confined in B, therefore, contracts ; and the elasticity of that within A forces the liquid up the tube, to a height proportionate to the intensity of the radiation. Such is the sensitiveness of the instrument, that the smallest cloud passing over it checks the rise of the liquid. Fig. 52. Price, 1 10 SELF-REGISTERING THERMOMETERS FOR COLD. FIG. 53. 63. Negretti and Zambra's Standard Minimum Thermometer. (Fig. 53.) consists of an enamelled glass tube, the bulb and parts of the bore of which is filled with perfectly pure colourless Spirits of Wine, in which floats freely a 46 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, B.C., black glass index. The tube is engine divided and mounted as shown in fig. 53. on either N. and Z.'s patent Porcelain or Opal Glass Scales. Directions for using Minimum Thermometers, for the Determination of the Minimum Temperature of the Air. Having caused the black index to flow to the end of the column of spirit, by slightly tilting the Thermometer, bulb uppermost, suspend the instrument, (in the shade with the air passing freely to it on all sides) by the two plates attached for that purpose, in such manner that the bulb is about half an inch lower than the end of the Thermometer furthest from the bulb, then on a decrease of temperature, the spirit will descend, carrying with it the index towards the bulb ; on an increase of temperature, the spirit will ascend in the tube beyond the index, leaving that end of the index furthest from the bulb indicating the extreme of cold or Minimum temperature. To re-set the instrument, simply raise the bulb end of the Thermometer a little, as before observed, and the index will again descend to the end of the spirit, ready for future observation. Price, in mounting as fig, 53 1 1 FIG. 54. 64. Negretti and Zambra's Standard Terrestrial Radiation Thermometer, (fig. 54). The bulb of this instrument is transparent, with the divisions engraved on its stem similar to that for solar radiation. In use, to be placed with its bulb fully exposed to the sky, resting on grass, with its stem supported by little forks of wood. Price, 110 FIG. 55. 65. Negretti and Zambra's Link shaped Bulb Minimum Thermometer, mounted either as a Terrestrial Radiation irstrument, fig. 55, o r on a Porcelain scale as fig. 53. This peculiar form of bulb was devised by Negretti and Zambra to obtain extreme sensitiveness by the large surface exposed to air. Price, 150 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 47 FIG. 57. FIG. 56. Brass Stand for use with Price, 5s. 6d. 66. Negretti and Zambra's Minimum or Terrestrial Radiation Thermometer with Brass Stand, (fig. 56). Price, 150 67. Concave Metallic Reflector on a Terrestrial Radiation Thermometer (fig. 57). N.B. As Alcohol Thermometers have a tendency to read lower by age, owing to the volatile nature of the alcohol allowing particles in the form of vapour to rise and lodge in the tube, it becomes necessary to compare them occasionally with a Mercurial thermometer whose index error is known ; and if the difference be more than a few tenths of a degree, examine well the upper part of the tube to see if any alcohol is in the bore, if so, detached por- tions can be joined to the main column by swinging the thermometer sharply backwards and forwards with a pendulous motion, keeping the bulb down- wards. When all the detached portions are joined, allow it to stand upright for an hour before again suspending it for observations. 68. Negretti and Zambra's Patent Mercurial Minimum Thermometer, represented by fig. 58, has a cylindrical bulb of large size. The reason for having the bulb large is to allow the internal diameter of the thermometer tube to be greater than that generally used for thermometrical purposes, so that a steel index, pointed at both ends, may move freely within when required. FIG. 58*.' In use, the Thermometer is suspended perpendicularly with the steel index resting on the surface of the mercurial column. As the mercury in the cylinder contracts from the effect of cold, that in the tube descends, and the index, of its own gravity, follows it ; on the contrary, as the mercury expands and rises in the tube, it passes the index on one side, and in rising, exerts a lateral pressure on the needle, and jambs it to one side of the tube, where it* remains firmly fixed, leaving the upper FIG. 58. 48 NEGRETTI AND ZAMBEA, HOLBOEN VIADUCT, B.C., point of the needle indicating the minimum temperature. In this thermometer the reading is always from the upper point of the needle, and not from the mercury itself. To extricate the needle from the mercury, a magnet is used, when, if the needle is embedded only a few degrees, it can readily be withdrawn without altering the position of the instrument. Should the magnet not be sufficient for the purpose, we simply turn the thermometer from the upright position, slightly elevating the bulb (58*2). The mercury and index will then flow into the small reservoir (58). Should the index not freely leave the tube with the mercury, assist it with a magnet and when the mercury and index are in the upper bulb (58*2), apply a magnet outside, which will attract and hold fast the index ; and whilst thus holding it, again bring the thermometer to the upright position, when the mercury will immediately fall back into the tube, leaving the index attached to the magnet (fig. 4), with which it is guided down to the surface of the mercury, ready for another observation. Price, 2 10 The value of these instruments may be estimated from the following letters, received from gentlemen by whom the thermometers have been tested since their invention. LEWISHAM, 1856, February 27. " GENTLEMEN, In reply to your note just received, I beg to say that your new Mercurial Minimum Ther- mometer was suspended by the side of two Minimum Thermometers of the best kind of the ordinary con- struction, on the day I received it from you, viz., 1855, November 21, and it has been examined and read every day since, during which interval of time the temperature has varied from 15 to 60. It has acted equally well within this range. In the course of the experiments, it was found that at times differences amounting to 2 and 3 existed in the minimum readings between those of the new mercurial and old spirit thermometers. These differences were found due to two causes. The one occurred at low temperatures, and on reference to independent registers, it was found that the readings of the mercurial were right, the difference being attributable to the sluggishness of the alcohol; and, in the other case, it was found that the index of the ordinary thermometer had unduly moved towards the bulb, the instru - ment having been shaken by the wind. "I consider the new Minimum Thermometer a very important addition indeed a more important one than the Maximum Thermometer of your invention, as by its means we can register all observations of temperature by the use of one fluid, and that the recognised standard for the measurement of heat. "With respect to your Maximum Thermometer, it acts admirably, and leaves scarcely anything to be desired. It has never been out of order during the four years* I have had it in constant use, and it does not seem possible to put it out of order, except by the destruction of the instrument. " I am, Gentlemen, your obedient Servant, "JAMES GLAISHEE, F.E.S. " Messrs. NEGRETTI and ZAMBRA, Opticians." " Secretary to the British Meteorological Society. The following is an extract from a letter to the inventors, Messrs. NEGRETTI and ZAMBRA, from E. J. LOWE, Esq., dated Observatonj, Beestrm, near Nottingham : "Your Patent Mercurial Thermometer is an admirable invention. I have worked it to my entire satisfaction. I have tested its usefulness in many different ways, every one of which has been perfectly satisfactory. It is certainly a meteorological triumph for which meteorologists must return you thanks." Care must be taken not to withdraw the magnet until the index is in contact with the mercury, for, if released before touching, it might plunge too deeply and give a false indication. The rule for re-setting it will be to bring * It is now more than twenty -nine years, and still the thermometer is perfect. 45, CORNHILL, B.C., AND 122, EEGENT STREET, W., LONDON. 49 the needle-point in contact with the mercury, and then withdraw the magnet, having previously ascertained that no particles of mercury are attached to the index. It may sometimes, though rarely, happen that, from the time a minimum temperature is registered by the index, and the time an observation is made, .the mercury may have risen so high in the tube as to completely pass the index, as shown (fig. 3). Should it so happen, the space which the index occupies will readily be observed, as it will be pressed to one side of the tube, causing a different appearance in that part, although the point of the needle may not be seen. If such be the case, apply a magnet to the spot where you see the index is fixed : this will hold the needle firmly. Then, by slightly tilting the thermometer bulb uppermost, the mercury will flow into the top bulb, leaving the index attached to the magnet, and quite uncovered. Having taken the reading, draw the needle into the top bulb, and hold ifc there whilst you adjust the thermometer by again bringing it to the upright position. So \ 70 I 31 $9 NEC PETTI & 2 AM BRA-, LONDON. FIG. 59. 68. Negretti and Zambra's Patent Mercurial Minimum Thermo- meter. The Patent Mercurial Minimum Thermometer is constructed as follows : A is the thermometrical or indicating tube, and B is a small vertical tube connected to it at right angles, about one inch from the bulb. In the tube B, at the point C, is inserted a platinum plug, which does not entirely fill the bore, as may be seen by elevating either end of the instru- ment, as the mercury will then flow in the tube A, either to or from the bulb, depending upon which end of the thermometer is elevated or depressed. To set for Observation, and use the Patent Mercurial Minimum Thermometer. Hold the thermometer with the bulb downwards until the bulb and tube B are quite full of mercury ; then raise the bulb end of the thermometer, and the mercury will flow from the tube B into the tube A, until it reaches the plug C, where it will be checked by the mercury adhering to the platinum plug the affinity of platinum for mercury being sufficient to arrest the flow of mercury, if not allowed to flow too rapidly. Should it overshoot the mark and go to the end of the tube A repeat the operation more carefully. Suspend the thermometer horizontally, and on a decrease of the tem- perature the mercury will fall in the tube A until it attains its minimum f>0 NEQEETTI AND ZAMBRA, HOLBORN* VIADUCT, E.G., temperature ; and on an increase of temperature the mercury will rise in the tube B, leaving the indicating column in A, registering the extreme degree of cold, or minimum temperature. To re-set the instrument for future obser- vation, simply raise the bulb end of the thermometer until the mercury again comes in contact, and is checked, by the platinum plug. This form of Mercurial Minimum Thermometer has one very great advantage over the preceding instrument, viz., it is much less liable to injury or breakage in transit. Price, fig. 69. 220 69. Actinometer, Sir John HerschelPs (fig. 60), for ascertaining the absolute heating effect of the solar rays, in which time is considered one of the elements of observation. The Actinometer consists of a large cylindrical thermometer bulb, with a scale.considerably lengthened, so that minute changes may be easily seen. The bulb is of transparent glass, filled with a deep blue liquid, which is expanded when the rays of the sun fall direct on the bulb. To take an observation, the Actinometer is placed in the shade for one minute, and read off, itis then exposed for one minute to sunshine, and its indication recorded ; it is finally restored to the shade, and its reading noted. The mean of the two readings in the shade, subtracted from that in the sun, gives the actual amount of expansion of the liquid pro- duced by the sun's rays in one minute of time. For further information see " Report of the Royal Society on Physics and Meteorology." Price, 770 70. Negretti and Zambra' s improved Isolated Glass Mountings for protecting Thermometer Scales from moist- ure. Many observers having found much trouble in reading the indications of Terrestrial Radiation and exposed Thermometers from the condensation of moisture on the inside of the protect- ing glass tubes or shields, Messrs. Negretti and Zambra have succeeded in perfecting a method of mounting up such instru- ments that quite obviates the difficulty. This improvement con- sists in so melting an external glass cylinder round both ends of the thermometer as to render the shield perfectly air-tight, in fact, to hermetically seal up the instrument in it so that no moisture can possibly accumulate inside the tube, whilst the bulb FIG 60 ^ *^ e thermometer is perfectly exposed to the air. Negretti and Zambra are now applying this improvement with great advantage to Thermometers, Hygrometers, and many other instruments required for out of door exposure. These isolating mountings will make a slight addition to the cost -of such Thermometers. 45, COBNHILL, B.C., AND 122, KEGENT STREET, W., LONDON. 51 FIG. 61. 71. Portable Patent Maximum and Minimum Registering Thermo- meters. Negretti and Zambra's Small Patent Maximum and Minimum Registering Pocket Thermometers, fitted into a secure and convenient pocket case, special for travellers, (fig. 61.) Price . . . .220 Larger Standard size ditto 2 10 The construction and use of the Portable Registering Thermometers is identical with N. and Z.'s larger Standard instruments, Nos. 40 and 53. These are the only Registering Thermometers that will travel without dera-ngement. Explicit printed instructions for use accompany each set. 72. Marie Davy's Actinometer, consisting of two Thermometers in vacuo, one with a bright and the other with a black bulb, both divided on the stems and mounted upon a suitable stand for out-door exposure. Price, 330 RULES FOB CONVERTING THERMOMETER READINGS. . To convert Fahrenheit readings to Centigrade. Subtract 32 and multiply the remainder by - y e.g. 68 P.=( 68 32)x- = 20 C. y To convert Fahrenheit readings to Reaumur. Subtract, 32 and multiply the remainder by - e.g. 68 F.=( 68 32) X - = 16 R. To convert Centigrade readings to Fahrenheit. Multiply by f and add 32. o To convert Reaumur degrees to Fahrenheit. Multiply by | and add 32. To convert Centigrade to Reaumur. Multiply by - 5 To convert Reaumur to Centigrade. Multiply by | NOTE. All of Negretti and Zambra's Standard Thermometers may be had with. Centigrade or Reaumur Scales to order. E2 52 NEGRETTI AND ZAMBRA, HOLBOEN VIADUCT, E.G., NEGRETTI & ZAMBRA'S PATENT BURLY RECORDING THERMOMETRICAL APPARATUS. 20 FIG. 62. 73. Negretti and Zambra's Patent Atmospheric Eecording Thermometer (fig. 62). For any hour determined upon, the clock carrying the Thermometer is -set (similar to an alarum clock), and when the hands arrive at this point of time, the movement of the l clock. releases a catch or detent, and the Thermometer* with its scale is revolved, the mercury then records the temperature of the air for that exact moment in a similar manner to those mentioned in the next page. These Recording Instruments are found to be a most important addition to our Meteorological Instruments, and no slight boon to observers in many parts of the world who are engaged in taking simultaneous observations with our own at fixed hours. ~ Price, as fig. 62. 440 * The Thermometer used with this apparatus is shown ly fig. 62a, and is fully described on page 53. 45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 53 NEGRETTI AND ZAMBIA'S PATENT HOURLY RECORDING THERMOMETRICAL APPARATUS. An instrument for obtaining automatic thermometer readings at stated intervals of time having long been sought for after many experiments, NEGRETTI & ZAMBRA have invented and constructed one both simple and accurate. 74. Negretti & Zambra's Patent Hourly Recording Thermometrical Apparatus. This new instrument consists of twelve Thermometers, mounted on a suitable stand, a good Clock, and a Galvanic Battery. The advantages are simplicity of manipulation, both in taking the recorded readings and setting the thermometers for future observations ; the most important one, being able to expose the thermometers at any distance from/ the clock and battery the only limit being the length of the conducting wires and the strength of the battery. Before describing the mechanical and electrical arrangements of the apparatus, we proceed to explain the construction and action of the thermometers themselves. This will be best understood by reference to the engraving, fig. 63. The bulb is cylindrical, and Mercury is the thermometrical fluid. The neck of the bulb is contracted at A, and upon the shape and fineness of this construction the success of the instrument depends. Beyond A the tube is bent, and a small catch reservoir is formed at B, for a purpose to be presently explained. At the end of the tube a small r.eceptacle, C, is provided. When the bulb is downward it contains sufficient mercury to fill the tube and a part of the reservoir, 0, leaving suf- ficient space in C for the expansion of the mercury. In this position no scale would be possible, as the apparent movement of the mercury would be con- fined to the space C. When the thermometer is held bulb upward, the mercury breaks off at A, and by its own weight flows down the tube, filling C and a portion of the tube above C, in relation to the existing temperature. The scale accordingly is made to read upwards from C. To set the instrument for observation, it is only necessary to place it bulb downward, then the mercury takes the temperature just as an ordinary thermometer. Whenever the existing temperature is required, all that has to be done is to turn the thermometer bulb upward ; the mercury will then break off at A, falls to 54 NEGRETTI AND ZAMBRA, HOLBORN YIADUCT, E.G., end C, and in this position the temperature can be noted. The engraving, fig. 63, shows the thermometer after it has been inverted. This reading may be taken at any time after the thermometer has been turned over, for the quantity of mercury in the lower part of the stem, which gives the reading, is too small to be sensibly influenced by a change of tempera- ture, while that in the bulb will continue to contract with greater cold and to expand with greater heat, and in the latter case some mercury will pass the contraction A, and may fall down and lodge at B, but it cannot go further so long as the bulb is upward, and thus the temperature to be read off will not be vitiated. It must be clearly understood that the thermometer is only intended to give the temperature at the time when it turned over. The divisions and figures are engraved upon the stem of these thermometers.* It will be seen in the accompanying drawing that twelve thermometers are mounted on the stand ; each one is sustained upon a metal arm in such a man- ner that it will fall over and become inverted by the release of a stop or detent from the joint action of the clock and galvanic battery. In the drawing, six of the twelve thermometers are shown inverted, the bulbs being upwards, the clock at each of the six successive hours having made contact and completed the galvanic circuit, and by the action of an electro- magnet released the detents, and allowed the thermometers to fall over and record the temperature for that moment. This action is produced by simple mechanism on the back of the clock dial, the contact being made at each hour It will be evident that the thermometers could be made to record half-hourly, or they might, by increasing the number, be made to register every fifteen minutes, or less, the only limit being the number of thermometers used. When the thermometers are all reversed, the readings may be quickly taken and the thermometers re-turned to their original positions, bulbs down- wards. Attached to the back of the clock dial, and in its centre, is a disc of ebonite, about two inches in diameter, with a hole in the centre to allow the spindle to pass on which the clock hands are fixed. Round the edge of this disc are twelve platina studs, one being opposite each hour on the clock dial ; each stud is separately connected to one of twelve terminals in the order of 1 to 12 at back of clock, viz. : The stud opposite 12 o'clock on the dial is carried to No. 12 terminal, &c., &c. Immediately behind the hour hand, at the back of the dial, and attached to the same spindle, is a metal spring which touches each stud in succession as the hour hand travels round. This spring is not insulated from the metal work of the clock ; consequently the current runs to the clock. * These Thermometers are divided with either Fahrenheit or Centigrade Scales, and their number may be increased to special order. 45, COBNHIU,, E 0., AND 122, REGENT STREET, W., LONDON. 55 Negretti and Zambra's Patent Apparatus for Recording Hourly Temperatures. (FiG. 64.) 56 NBGRETTI AND ZAMBEA, HOLBOEN YIADUCT, E.G., Fixed at the back of the clock dial, near its outer edge, are two little glass cups containing mercury, one of which is connected to the metal work of the clock ; the other glass cup is connected to the thirteenth terminal on the back of the clock. Immediately over these two cups, and fixed to an arm or lever, is a forked piece of platina wire, which, when depressed into the cups, forms a connecting bridge from one to the other. The lever is depressed when one end is lifted by the minute hand of the clock. This is accomplished by means of a wedge-shaped piece of steel brought through to the front of the dial, and acted upon by the minute hand directly over twelve o'clock ; when the minute hand approaches twelve, it presses the left angle of the wedge and lifts it. A terminal at the outside of a box containing twelve magnets is connected to a metal bar running the entire length of the same, to which is attached one end of a wire from each of the twelve electro-magnets ; the other ends of the wires from the electro-magnets are separately connected to the twelve terminals under the box containing the magnets, thence by separate wires to the twelve terminals on the clock, in the order of from 1 to 12 as marked. We will now suppose the time to be six o'clock. The battery is connected as follows : One pole to the thirteenth terminal on the clock, the other pole to the terminal at end of box on the Recording apparatus. The electric circuit is now complete. From the battery to the thirteenth terminal on clock, then to one of the glass cups, over the little bridge of wire to the other glass cup, thence through metal work of the clock to the spring, which spring touches upon the stud at the back of the hour hand (at, say six o'clock), from thence to No. 6 terminal on the back of the clock, from there to No. 6 terminal under the box containing the electro-magnets, through No. 6 magnet to the bar above, then to the terminal at the end of the box, and back to battery. In its circuit, No. 6, magnet attracts its keeper, the catch falls, and allows No. 6 thermometer to turn over, and in like manner throughout the series. Price, fig 64. 52 10 NEGRETTI AND ZAMBRA'S SUNSHINE RECORDER. 75. This instrument shown by fig. 65 consists of a glass sphere ground perfectly true, mounted upon a brass frame, with suitable adjustments for placing its axis parallel with the axis of the earth ; it has also a divided semi-circle arranged to adjust the apparatus for use in any latitude. Surrounding one-half of the glass sphere is placed a concentric metal plate, for holding the prepared and divided paper cards, upon which the record is burned by the concentrated Solar rays. 45, COENHILL, E.G., AND 122, BEGENT STEEET, W., LONDON. 57 FIG. 65. Two grooves are formed upon the concentric plate, by which the position of the divided cards can be varied to suit the elevation of the sun at different seasons of the year. In use, the Sunshine Recorder should be placed geographical North and South, similar to a sun dial. Price, fig. 65. 12 12 A supply of prepared cards sufficient for one year's use . . . 1 12 FIG. 66. FIG. 67. 76. Jordan's Sunshine Recorder (Patent), made and supplied only by Negretti and Zambra. 58 NEGRETTI AND ZAMBRA, HOLBOEN VIADUCT, E.G., Since the indention in 1853 of Mr. CAMPBELL'S instrument for automatically registering the duration of Sunshine, the subject has become of increasing interest, and improved forms of his instrument have been generally adopted at the principal Observatories and Meteorological Stations where the hours of bright Sunshine are regularly observed and registered. These ingenious instruments are perfect recorders of Sunshine so long as the sky is clear, but are too costly to come into general use by the greater number of observers now- interested in the subject. It is to meet this difficulty that the instrument now introduced has been designed. We believe that it meets all the requirements ; it is accurate in its action, of simple construction, and sufficiently cheap to come within the means of all those who are interested in this comparatively new branch of meteorological science. Half Size. FIG. 68. The action of Mr. JORDAN'S Sunshine Recorder differs entirely from that of the instrument above referred to, inasmuch as the results are obtained by means of photography, instead of by the burning power of the concentrated solar rays ; it is, however, only on days when the atmosphere is a little hazy, or the sun slightly obscured by thin, filmy cloud, that there is any important difference in the record of the two instruments ; at such times the photographic registering instrument will probably show an excess of sunshine, as under certain conditions the thin film of cloud or haze interferes more with the action of the heat rays than it does with the actinic rays. The new instrument which is figured on the other side consists of a dark cylindrical chamber, on the inner circumference of which is placed a carefully prepared photographic paper. The ray of sunlight being admitted into this chamber through small apertures in the side, is received on the sensitized paper or chart, and travels around it by virtue of the earth's rotation, leaving a distinct trace of chemical action, thereby registering its duration, and the degrees of its intensity, varied by every passing cloud. The cylinder is mounted on a suitable stand, having simple means of adjustment, for the different seasons of the year, and for the use of the instrument in any latitude. Price. Sunshine Recorder Fig. 66 330 Ditto Fig. 67, with rackwork adjustment and clamping screws 550 A Box containing 100 prepared CHARTS, with instructions- Fig. 68 100 45, COBNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 59 The Charts are printed upon sensitized paper, ruled with vertical lines, representing the hours and minutes of the day; they are supplied, ready for use, in boxes containing 100 each. The records obtained are rendered permanent by simply washing the papers for a few minutes in cold water and afterwards drying them between blotting-paper. INSTRUCTIONS FOR FIXING- JORDAN'S SUNSHINE RECORDER. 77. Select a suitable position which has the full range of the sun at all seasons of the year. Provide affirm support with a perfectly level top, place the Instrument upon it (the lid of the cylinder facing north), and when the sun is on the meridian (12 o'clock) turn the instrument on its base until the shadow of the pin on the lid of the cylinder coincides with the vertical line on the white glass behind it. When this adjustment has been correctly made, the instrument may be permanently screwed down to its support, then incline the cylinder on its horizontal axis, by means of the milled head at the side, until the point of the shadow of the aforesaid pin falls on the point of intersection of the two lines, and clamp securely by means of the opposite milled head, the ray of sunlight passing through the central aperture will then fall on the twelve o'clock division of the chart. This adjustment will require to be altered occasionally as the seasons vary, the necessity for alteration being shown by the position of the trace above or below the central line of hour divisions on the hart. The charts should be inserted in the cylinder each day after sunset, ready for the following day, the ends being placed against the stops provided for the purpose. On removing the charts from the instrument after the day's observa- tion the number of hours recorded should at once* be tafadated, the trace may then be rendered permanent by immersing the chart for a few minutes in cold water, until the surface becomes white and the trace a bright blue colour ; it should then be removed and dried between blotting paper. Care must be taken not to expose the sensitized charts to the daylight longer than is necessary for removing and inserting them in the cylinder. The cylinder being held in position on the frame by a clamping screw can be easily removed for the purpose of changing the chart, which may be done either at the place of observation or indoors * This precaution is necessary that any very faint traces on the chart may not be lost before registering, by too long immersion in water, or it may be advisable to mark with a pencil the limits of the trace before placing in water. GO NEGEETTI AND ZA.MBRA, HOI/BORN VIADUCT, B.C., NEG-BETTI & ZAMBEA'S RECORDING DEEP SEA THERMOMETERS. 78. Deep Sea Sounding Thermometers, Self-Registering, the original double tube principle, invented by Negretti and Zambra, specially- constructed for the Board of Trade and Admiralty. Warranted to stand a pressure of 450 atmospheres. Price 2 10 This manner of protecting the bulb was invented by Messrs. Negretti and Zambra in 1857, and is described by the late Admiral R. FitzRoy, in the first number of Meteorological Papers, p. 55, published July 5th. 1857, as follows : " Referring to the erroneous readings of all thermometers, consequent on their delicate bulbs being compressed by the great pressure of the ocean, he says : ' With a view to obviate this failing Messrs. Negretti and Zambra undertook to make a case for the weak bulbs, which should transmit temperature, but resist pressure. Accordingly a tube of thick glass is sealed outside the delicate bulb, between which and the casing is a space all round, which is nearly filled with mercury. The small space not so filled is a vacuum, into which the mercury can be expanded, or forced by heat or mechanical compression, without doing injury to or even compressing the inner or much more delicate bulb.'" The bulb of the Thermometer thus protected resists the pressure of the ocean, which varies according to its depth that of three thousand fathoms being something like three tons pressure upon the square inch. 79. Negretti and Zambra's Small Deep Sea Sounding Thermometers, the so-called Dr. Miller's pattern in Copper. Case. Price 2 10 330 R. H. SCOTT, Esq., F.R.S., in a paper published in the Journal of the Meteo- rological Society, January 17th, 1872, speaking of Negretti and Zambra's Deep- Sea Thermometers, described by Admiral FitzRoy in the first number of Meteorological Papers, published July 5th, 1857, says : " The number of the thermometers of this particular pattern, which was supplied to the Meteorological Department of the Board of Trade by Messrs. Negretti and Zambra, the makers, was upwards of fifty, and they were supplied to several ships in the Royal Navy, especially those employed on certain well-known deep-sea sounding expeditions. I was not able to find any record of any of these thermometers having been tested in an hydraulic press, and, accordingly, as soon as the Miller pattern thermometer had been definitely adopted by the Hydrographer, it was resolved to subject one of the old thermometers (Negretti and Zambra's) in the Meteorological Office to the same test as that which the new instruments were made to undergo, in order to see whether or not the construction of the original instruments offered sufficient security against alteration of the shape of the bulb, owing to pressure. The experiments were carried out on the 28th of September, 1869, in 45, COBNHILL, B.C., AND 122, EEGENT STREET, W., LONDON. 61 the presence of Capt. Toynbee and Mr. Strachan, and the results of the testing have been published in the report of the Meteorological Committee of the Royal Society for 1869. The concluding sentence of this report was as follows (page 32) : "'The foregoing experiments are sufficient to show that the original thermometers described by Admiral FitzRoy were good and trustworthy instruments, in so far as regards their capability of resisting pressure.' " NEGRETTI AND ZAMBRA'S NEW RECORDING DEEP-SEA THERMOMETERS. 80. These Instruments differ from all other Recording Thermometers in the following important particulars : I. The Thermometer contains pure mercury only, without any alcohol or other fluid. II. It has no indices or springs, and its indications are by the column of mercury only. III. It can be carried in any position, and cannot be put out of order except by breakage. And chiefly, it will indicate and record the exact temperature at any depth of the sea, irrespective of either warm or cold currents or stratum through which the Thermometer may have passed in its descent or ascent. This last very special quality renders N. and Z.'s Thermometers superior for Deep Sea tempera- ture to any others ; for those used in the Challenger expedition are liable to give erroneous indications, owing to their indices slipping, and otherwise getting defective (this was proved by Messrs. Negretti and Zambra at a Meeting of the British Meteorological Society) ; and under certain conditions of temperature it is not possible by these old Thermometers to obtain true temperatures at certain depths which might be required. The construction of Negretti and Zambra's original Deep Sea Thermometer is as follows : In shape it is like a syphon with parallel legs, having a continuous communication, as seen in the annexed figure, 69. The mounting of the Thermometer is pivoted on a centre, and being attached in a perpendicular position to a simple apparatus (which will be presently described), is lowered to any depth in the water that may be desired. In its descent the Thermometer acts as an ordinary instrument, the mercury rising or falling according to the temperature of the stratum through which it passes ; but so soon as the descent ceases, and a reverse motion is given to the line, so as to pull up the apparatus towards the surface, the Thermometer turns once on its centre, first bulb uppermost, and afterwards bulb downwards. This causes the mercury, which was in the left-hand column, first to pass into the dilated syphon bend at the top, and thence into the right hand tube, where it remains, indicating on a graduated scale the exact temperature at the time it was 62 NEGEETTI AND ZAMBRA, HOLBORN TIADUCT, K C. turned over. Fig. 69 shows the position of the mercury after the instrument has been thus turned on its centre. A is the bulb ; B the outer coating or protecting cylinder ; C is the' space of rarefied air, which is reduced if the outer casing be compressed ; D is a s mall glass plug on the principle of Negretti and Zambra's Patent Maximum Ther- mometer, which cuts off, in the moment of turning, the mercury in the tube from that of the bulb, thereby insuring that none but the mercury in the tube can be trans- ferred into the indicating column ; E is an enlargement made in the bend so as to enable the mercury to pass quickly from one tube to another in revolving ; and F is the indicating tube or Thermometer proper. In its action, as soon as the Thermometer is put in motion, and immediately the tube has acquired a slightly oblique position, the mercury breaks off at the point D, runs into the curved and enlarged portion E, and eventually falls into the tube F, when this tube resumes its original perpendicular position. The contrivance for turning the Thermometer over may be described as a metal frame with a vertical screw propeller; to this frame (fig. 70) the instrument is attached- In its descent through the water the screw is lifted out of gear and revolves freely on its axis ; but so soon as the apparatus is pulled up towards the surface the screw falls into gear and revolves in the contrary direction, turning the Thermometer over once, and then becoming locked and immovable, the temperature is recorded for that moment. Price 10 10 This arrangement of Deep Sea Thermometer (fig. 70) having been found defective, Negretti and Zanibra have abandoned its manufacture it being norc quite superseded by their recently improved Thermometers, particulars of which vill be found in the following pages. Our description is therefore only inserted as a matter of history in connection with the invention of Deep Sea Recording Instruments. FIG. 69. 45, COENHILL, E.G., AND 122, KEGENT STREET, W., LONDON. 63 NEGRETTI & ZAMBRA'S NEW PATENT STANDARD MARINE REGISTERING THERMOMETERS.* 81. " The most'successful Deep- Sea Thermometer hitherto has been Six's Thermometer, with the bulb protected from pressure, as invented by NEGRETTI AND ZAMBRA in 1867. Nevertheless there are several disadvantages inherent in the principle of construction of Six's instrument. The indices are unreliable, as, however carefully fitted, they may slip down by gravity, and even shift upward by sudden lifting motion ; so that the observations are always more or less liable to error : the index error also is very liable to alter by the shifting of the spirit, or by bubbles of spirit getting among the mercury ; and unless the observer is well-trained in its management, and takes care to compare it with a correct ordinary ther- mometer every time it is used, there is no guaranteeing 1 its accuracy of indication. Further, its accuracy in its best condition does not attain to fractions of a degree, as it cannot be read off closer than about half a degree. Then it must be kept in the vertical position, or it is certain to become more or less deranged in transit. " However, so long as it sufficed to observe the nearest degree of temperature, the improved protected Six's answers the purpose of a deep-sea thermometer, with careful management and checking ; but lately the bottom temperature of shallow seas and of rivers has come under investigation, and for this purpose Six's instrument is unsuitable. " Between the temperature of the surface of the sea and that at the depth of a few fathoms, the differences to be determined are found to be not degrees of the thermometer, but fractions of a degree ; hence, the observations to be worth anything at all, must be made with an undoubtedly accurate thermometer. " During the last two or three years systematic observations of the surface and bottom temperatures have been taken from the various lightships off the British coasts, under the direction of the Meteorological Office. This investigation of the temperatures of the British seas has been urged upon the Government by naturalists and physicists interested in the question of the food supply of the people as affected by the take of fish. What is required to be made evident is, whether any, and what, effect temperature has upon the habits and migrations of fish, so as to tend to a right understanding of the conditions favourable for the development of the various species of fish, and the best seasons and temperature indi- cations for their capture. This investigation, commenced with Six's Thermometers, has at present only shown that such instruments are not sufficiently reliable for the purpose ; and it was represented by the Government to Messrs NEGRETTI AND ZAMBRA, that a more perfect and stable deep-sea thermometer was a desideratum. They accordingly turned their attention to the matter, and the result is the new STANDARD DEEP-SEA THERMOMETER. " The construction of this thermometer will be readily understood by reference to the sketch diagram fig. 71. The bulb is cylindrical, and mercury is the thermometrical fluid. The neck of the bulb is contracted in a peculiar manner at A, and upon the shape and fine- ness of this contraction the success of the instrument mainly depends. Beyond A the tube is bent, and a small catch reservoir is formed at B, for a purpose to be present/I^ explained. At the end of the tube a small receptacle, C, is provided. When the tube is downward, the glass contains sufficient mercury to fill the bulb, tube, and a part of the reservoir C, if the temperature is high, leaving sufficient space in C for the expansion of the mercury. In this position no scale would be possible, as the apparent movement of the mercury would be confined to the space C. When the thermometer is held bulb upward, the mercury breaks off at A, but by its own weight flows down the tube, filling C and a portion of the tube above C, in relation to the resisting temperature. The scale accordingly is made to read upwards from C. To set the instrument for observation it is only necessary to place it bulb down- * Description condensed from " ENGINEERING," Mai-ch 22iid, 1878. 64 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., DESCENDING. ASCENDING. FIG. 72. FIG. 71. FIG. 73. ward, then the mercury takes the temperature just as an ordinary thermometer. When at any time or at any place the temperature is required, all that has to be done is to turn the thermometer bulb upward, and keep it in this position until read off. " The reading may be taken at any time after, for the quantity of mercury in the lower part of the stem which gives the reading is too small to be sensibly influenced by a change of temperature, unless it is very great, while that in the bulb will continue to contract with greater cold and to expand with greater heat, and in the latter case some mercury will pass the contraction A, and may fall down and lodge at B, but it cannot go further so long as the bulb is upward, and thus the temperature to be read off will not be vitiated. Now, when- ever the thermometer can be handled, it can readily be turned bulb upward for reading off the existing temperature. At a depth in the sea, some contrivances must be provided for turning the thermometer bulb upward. For this purpose the thermometer is fitted into a hollow wooden frame, loaded with shot, free to move from end to end of it, and sufficient to render the whole instrument just vertically buoyant in sea-water. " In using the thermometer a cord is rove through the hole in the frame nearest the bulb, and the instrument is fastened by this cord to the sounding line. In descending the thermometer will be pulled down with the bulb downwards ; but upon being pulled up, the instrument, owing to the resistance through the water, and consequent displacement of its centre of gravity, will turn over and come up bulb uppermost, the temperature of the spot where it turned over will then be indicated, as shown in the illustrations. See figures 72 and 73. " As regards the thermometer itself it was necessary, in order to make it perfectly satisfactory, to protect it against pressure, even if intended for shallow seas, as well as for 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LOKDON. 65 the deepest. For whether used in deep or shallow water, unless withdrawn from pressure, its indications would always be more or less in error. Like an ordinary thermometer it is devoid of air, and so quite different from Six's, which, containing compressed air, has a certain internal resistance. Hence it would be more affected by pressure than Six's, how- ever thick the glass of the bulb. By the simple expedient of placing the thermometer entirely in a shield of glass hermetically sealed (see fig. 4 on next page), the effect of external pressure is entirely eliminated. The shield must of course be strong, but need not be exhausted of air. It must, however, render the enclosed thermometer more difficult to be affected by changes of temperature ; in other words, it will make it sluggish. " To counteract this sluggishness, in that portion of the shield surrounding the bulb, some mercury is introduced, and confined there by a partition cemented in the shield around the neck of the thermometer bulb. This mercury acts as a carrier of heat from the exterior of the shield to the interior of the thermometer : and the efficacy of this arrangement has been experimentally determined, the instrument thus protected being, in fact, far superior in sensibility to Six's thermometer. " So long as the shield withstands the pressure, that is, does not break, the thermometer will be unaffected by pressure, and there is abundant experience to show that such a shield will stand the pressure of the deepest ocean. The greatest pressure can never affect a thermometer so protected. Doubtless the shield will be compressed a little under great pressure, but this can never exert an internal pressure sufficient to have an appreciable effect upon the thermometer. This method of shielding is quite efficacious, and deep-sea thermometers so protected do not require to be tested for pressure in the hydraulic press. The thermometer will simply require to be tested for sensitiveness and for errors of gradu- ation very accurately ; because it is a standard instrument adapted to determine very small differences of temperature as well as large ones, even one or two- tenths of a degree in shallow waters. The test for sensitiveness should determine how many seconds the instru- ment requires to take up a change of 5 deg. rise or fall ; and the time has been found from 5 to 10 seconds. " A considerable number of these instruments have already been tested at the Kew Observatory with perfectly satisfactory results, which place beyond doubt their value as Standard Deep-sea Thermometers. " This instrument possesses great advantages. It has no attached scale, th'e figuring and graduations are distinctly marked on the stem itself, and the shield effectually preserves them from obliteration by sea-water. The part of the stem which forms the background to the graduations is enamelled white,* to give distinctness to the mercury. " The hole at the top of the frame is for the purpose of lowering and keeping the thermometer upright until it has reached the water. This is effected by putting a cord through the hole, and both ends of it kept in the hand until the thermometer has reached the water, then one end is let go and the cord pulled on board ; this operation is not imperative, but it saves the thermometer from being knocked about previous to reaching the water." Negretti and Zambia's Patent Standard Marine Thermometer (fig. 72) . Price 2 10 * Enamelling the bac/c of Thermometer Tubes is on important invention by Negretti and Zambra. Most of the extremely sensitive Thermometers that are now made (such as Clinical Thermometers) would have been almost useless but for this improvement. 1 cubic foot of Sea Water weighs 62*425 lbs.=557 cwt , or 0-028 of a ton. Sea Water freezes at 28. Boils at 213 2 ; variable with the density. 80 miles from the Island of St. Thomas, at a depth of 3 875 fathoms, the temperature of the Sea was found to be 34 Fahrenheit ; the pressure at this depth 4* tons to square inch. The pressure at 100 feet is found by Divers difficult to bear for any lengthened period. Man cannot sustain a greater pressure than 6 Fathoms, or 120 feet. Weights of 6 or 8 hundredweight require two Hours to fall through 3 miles of Sea Water, owing to the friction of the water on the rope or wire. Dr. CARPENTER. F C6 NEGEETTI AND ZAMBEA, HOLBOEN YIADUCT, B.C. NEGRETTI & ZAMBRA'S PATENT IMPROVED-FRAME STANDARD DEEP-SEA THERMOMETER. H c FIG. l. FIG. 3. FIG 4. FIG. 2. 82. NEGRETTI & ZAMBRA'S Improved Standard Deep-sea Thermometer has been abundantly proved to be the only thermometer that ought to be used in researches into the temperature of the sea below the surface. It is quite applicable for testing the temperature of the sur- face water, but merely for this purpose a less expensive instrument would usually be employed. For taking temperatures at moderate depths, from a few feet to a few hundred fathoms, NEGRETTI AND ZAMBRA'S Wooden Float form amply suffices and is quite suitable. The only objection that has been raised to this wooden float is, that in sounding to great depths a check upon the line, caused by the motion of the ship due to the heave of the sea, may make it turn over and register, so that the temperature at the desired depth is not obtained. In very deep soundings it is often desirable to have a series of thermometers 45, COBNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 67 upon the line at different depths ; and in this case the frequent checks and stoppages upon the line during the hauling up, either from the pitching of the ship or in detaching the thermometers as they arrive at the surface, lead to some uncertainty in the results. To do away with all doubt as to the accuracy of the record brought up by each thermometer is the object of the new form of the Standard Deep-sea Thermometer. The improvement is due to suggestions kindly furnished to NEGBETTI AND ZAMBBA by Commander MAGNAGHI, of the Royal Italian Navy. By means of it the thermometer may be attached to any part of the line during the descent ; and after the first regular haul in of from 10 to 80 feet, according to adjustment, any number of stoppages or any amount of line may be afterwards run out without altering the temperature obtained at the commencement of hauling up. Several thermometers can now be fastened upon the line and serial temperatures obtained at any required depth with certainty. The apparatus will be best understood by reference to the accompanying figures (Nos. 1 and 2). A is a metallic frame in which the case B, containing the thermometer, is pivoted upon an axis H, but not balanced upon it. C is a screw-fan attached to a spindle, one end of which works in a socket D, and on the other end is formed the thread of a screw E, about half an inch long, and just above it is a small pin or stop P on the spindle. G is a sliding stop-piece against which the pin F impinges when the thermo- meter is adjusted for use. The screw E works into the end of the case B the length of play to which it is adjusted. The number of turns of the screw into the case is regulated by means of the pin and stop-piece. The thermometer in its case is held in position by the screw E, and descends into the sea in this position (Fig. 1), the fan C not acting during the descent because it is checked by the stop F. When ascent commences the fan revolves, raises the screw E, and releases the thermometer, which then turns over and registers the temperature at that spot, owing to the axis H being below the centre of gravity of the case B as adjusted for the descent. Each revolution of the fan represents about 10 feet of move - ment through the water upwards, so that the whole play of the screw requires 70 or 80 feet ascent ; therefore the space through which the thermometer should pass before turning over must be regulated at starting. If the instrument ascends a few feet by reason of a stoppage of the line while attaching other thermometers, or through the heave of the sea, or any cause whatever, the subsequent descent will cause the fan to carry back the stop to its initial position, and such stoppages may occur any number of times provided the line is not made to ascend through the space necessary to cause the fan to release the thermometer. When the hauling-in has caused the turnover of the thermometer the lateral spring K forces the pin L into a slot in the case B and clamps it (as seen in fig. 2) until it is received on board so that no change of position can occur in the rest of the ascent from any cause. The case B is cut open to expose the scale of the thermometer, and is also perforated to allow the free entry of the water. The construction of the Thermometer will be understood by referring to Figs. 3 and 4 and also to the description given on page 63 (fig. 71) Price for NEGEETTI AND ZAMBEA'S New Patent Improved Frame Standard Deep-Sea Thermometer, as fig. 1. The Hydrographic Bureau at Washington published lately the following results of a series of observations carried out in order to determine the length, depth, and duration of ocean waves : The longest wave hitherto observed is said to have had a length of half-a-mile, and to have spent itself in 23 seconds. During storms in the North Atlantic waves sometimes extend to a length of 500 ft. and 600 ft., and last from 10 to 11 seconds. The most careful measurements of the height of waves give from 44 to 48 feet as an extreme limit ; the average height of great waves is about 30 ft. These measurements refer to ordinary marine action, and do not relate to earthquake action or other exceptional agencies. F 2 68 NEGRETTI AND ZAMBKA, HOLBOJiN VIADUCT, E.G., INSTRUMENTS FOR ASCERTAINING THE HUMIDITY OF THE ATMOSPHERE. THE instruments used for observing the amount of moisture contained in the atmosphere are called Hygrometers. They are without doubt of all Meteorological instruments the most useful and valuable. To ascertain with exactness the Hygrometric condition of the air is of the utmost importance both to the Physician and Agriculturist. By observing the varying amount of vapour or moisture in the air, the one is enabled to regulate its condition as best suited to his patient's requirements, and the other by closely watching the movements of the Barometer in connection with the Hygrometer can anticipate probable atmospheric changes that may prove beneficial or injurious to his crops. There are many Hygrometers constructed as Weather Indicators only, simply showing the approximate condition of the air if it be wet or dry. Such instruments, however ingenious, are not of any scientific value. For more exact and precise observation the Hygrometers of Daniell, Regnault, and Mason are chiefly used the latter, viz., Mason's, from its extreme simplicity is now universally in use, and in connection with the valuable tables compiled by James Grlaisher, Esq., F.B.S., the dew point can be ascertained with great exactness and ease. In connection with the Hygrometer, the dew point will be frequently spoken of. This may be described in a few words as the amount of water which the air can sustain in an invisible form increasing with the temperature ; but for every definite temperature there is a limit to the amount of vapour which can be thus diffused. When the air is cooled the vapour present may be more than it can sustain ; part will then be condensed either in the form of dew, rain, hail, or snow. The temperature which the air has when it is so fully saturated with vapour that any excess will be deposited as dew, is called the dew-point. " To measure the quantity of dew deposited each night, an instrument is used called a Drosometer. The most simple process consists in exposing to the open air bodies whose exact weight is known, and then weighing them carefully when covered with dew. According to Wells, locks of wool, weighing about eight grains, are preferred, divided into spherical masses of the diameter of about two inches.'' Kcemtz. 45, COBNHILL, E.G., AND 122, BEGENT STEEET, W., LONDON. 69 83. Saussure's Hygrometer (fig. 74), for showing changes in the hygrometric condition of the atmosphere on a graduated arc, by the contraction and elongation of a human hair, this acting the reverse of string or cord, stretching when moist and contract- ing when dry. A thermometer is attached to the scale. Price, 1 10 Although a most elaborate Treatise on the construction and use of this Hygrometer was written by its inventor, M. Horace Benedict de Saussure, Professor of Philosophy, at Geneva, in 1783, this instrument may be regarded more as an ornamental curiosity than of any scientific value. FIG 74. 84. Leslie's Thermometric Hygrometer (fig 75). It will be seen that Leslie's instrument is the elementary form of Mason's Wet and Dry Bulb Hygrometer, by which it is entirely superseded. This instrument consists of a glass tube, terminated with a bulb at each end, as fig. 75. The tube is partly filled with sulphuric acid, tinged by carmine. One of the balls is covered with muslin, and kept continually moistened with water, drawn from a vase placed near it by the capillary attraction of a few strands of cotton- wick. The descent of the coloured liquid in the other stem will mark the diminution of temperature caused by the evaporation of the water from the humid surface. The drier the ambient air is, the more rapidly will the evaporation go on ; and the cold produced will be greater. When the air is nearly saturated with moisture, the evaporation goes on slowly ; the cold produced is moderate, because the ball regains a large portion of its lost heat from surrounding bodies. The degree of refrigeration of the ball is an index of the dryness of the air. When this hygrometer stands at 15, the air feels damp ; from 30 to 40, we reckon it dry ; from 50 to 60, very dry ; and from 70 upwards, we should call it intensely dry. A room would feel uncomfortable, and would probably be unwholesome, if the instrument in it did not reach 30. In thick fogs it keeps almost at the beginning of the scale. Price, 110 85. Daniell's Hygrometer, for ascertaining the dew-point by direct observation (fig. 76), invented about the year 1820, by the late Professor Daniell, of King's College, London. It consists of a glass tube, bent twice at right angles, and terminating, at each end, in a bulb. In the long limb of the tube is enclosed a delicate thermometer, which descends to the centre of the bulb, which is about three- parts filled with sulphuric aether. All the other parts of the tube are carefully freed from air, so that they are occupied by the vapour of the aether. This bulb is made of black glass ; the other bulb on the shorter limb is transparent, and 70 NEGEETTf AND ZAMBKA, HOLBORN VIADUCT, E.C., FIG. 75. FIG. 76. FIG. 77. covered with a piece of fine muslin. The support for the tube has a delicate thermometer attached, to show the temperature of the external air. This instrument gives the dew-point by direct observation, and is to be used at an open window facing the north in the following manner : Having fixed the tube upon the stand, with the bulbs vertically downward, the ^Ether is all caused to flow into the lower ball by inclining the tube. The temperature of the air is noted by the exposed thermometer. Then some ^Efcher is poured upon the muslin-covered bulb. The rapid evaporation of this ^Ether cools the bulb and causes condensation of the ^Ethereal vapour in its interior. This gives rise to rapid evaporation of the Mtlaer in the lower bulb, whereby its temperature is greatly reduced. The air in the vicinity is deprived of its warmth by the cold bulb, and is soon cooled to the temperature at which it is perfectly saturated with the vapour which it contains. Cooled ever so little below this temperature, some aqueous vapour will be condensed, and will form a dew upon the black- glass bulb. At the first indication of the deposit of dew the reading of the internal thermometer is taken : which is the dew-point. In very damp or windy weather the .^Ether should be slowly dropped on the bulb, otherwise the descent of the mercury in the Thermometer is so rapid as to render it difficult to be certain of the temperature. Should this occur, the observation may be repeated by watching the temperature at which the ring of dew disappears, the mean of the two readings will be the correct point of precipitation. The greatest differ- ence observed by Mr. Daniell in the course of four months' daily experiments between the external thermometer and the internal one at the moment of 45, COKNHILL, E.G., AND 122, EEGENT BTRKET, W M LONDON. 71 precipitation in the natural state of the atmosphere was twenty degrees. When Darnell's Hygrometer is required to act merely as a weather-glass, to predict the greater or less probability of rain, &c., the difference between the con. stituent temperature of the vapour (shown by the interior thermometer), and the temperature of the air (shown by the exterior thermometer), is all that is necessary to be known. The probability of rain or other precipitation of moisture from the atmosphere, is in inverse proportion to this difference. There are several difficulties connected with the use of Daniell's Hygrometer that are in a great measure overcome in Regnault's Instrument. Fig. 76 Price, 330 86. Jones's Hygrometer (fig. 77). This instrument is the same in principle as Daniell's Hygrometer, but simpler in its construction. The tube of the Mercurial Thermometer is bent so as to bring its bulb vertical and parallel with its stem. This bulb is one inch long, and of a conical shape, with a flattened top or surface of black glass projecting a little beyond the sides. Below the flat surface this bulb is covered with black silk. The Hygrometer is mounted and supported on a brass stand in such a manner that the black surface can be inclined towards the light. When used the temperature of the air is first to be noted. ./Ether is to be poured on to the silk cover of the bulb, and the condensation of moisture takes place upon the black surface of the bulb. Then, by again noting the temperature, the dew point may be known. Price, 2 10 87. Regnault's Condenser Hygrometer, (fig. 78), for ascertaining by direct observation the dew-point, is superior to Daniell's, from its being more certain in its indications, and economical in use. It consists of two highly- polished silver cylinders, into the upper part of which are cemented thin glass tubes ; these have brass covers, arranged to receive and support two delicate Standard Thermometers, the bulbs of which descend nearly to the bottom of the silver portion of these chambers. Each chamber has a small internal tube carried down from the brass cap to within a short distance of the bottom, to admit the passage of the air, which is drawn through both chambers by an Aspirator, (fig. 78*) connected to the base of the hollow upright and arms supporting the cylinders. To use this Hygrometer, aether is poured into one chamber sufficient to cover the bulb of the thermometer, and then the thermometers being inserted into both cylinders the instrument is now connected to the aspirator, and by it the air is drawn through both cylinders down the internal tubes, passing in one chamber in bubbles through the aether, and in the other chamber simply around the thermometer. The tube in this empty cylinder is of such a diameter as to ensure similar quantities of air passing through each chamber. After a short time the passage of the air through the aether will cool it down to the dew-point temperature and the external portion of the silver chamber containing the aether will become covered with moisture. The degree shown 72 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.G. FIG. 78. FIG. 79. by the thermometer in the aether at that instant will be the temperature of the dew-point ; the second thermometer showing the temperature of the air at the time of observation. Price, in case .... 5 5 Aspirator for ditto (fig. 78*) 1 15 to 2 15 88. Regnault's Condenser Hygrometer (fig. 56), of simpler form, only one cylinder or chamber being nsed. The air in this arrangement is blown through the aether by the mouth. A small thermometer is attached to the stand to show the temperature of the external air. Price, in Case, with ^Ether Bottle (fig. 79) 3 10 For practical utility and convenience in use the Wet and Dry Bulb Hygro- meter is vastly superior to all others. The engravings, N"os. 80 to 86, will show the various forms of Negretti and Zambra's Hygrometers from the simplest to the Standard instruments as manufactured by Negretti and Zambra for the various Scientific Observatories and Societies, the Government Meteorological Stations, the Metropolitan and County Hospitals, &c., &c. Most of these Hygrometers ' have Negretti and Zambra's Patent Porcelain Scales and Enamelled Tubes. 89. Wet and Dry Bulb Hygrometer, simple form, on a stand (fig. 80) for table or shelf. Price, 12s. 6d., 16s., and 110 90. Ditto Ditto Ditto plain, portable, brass stand and metal cover (fig. 81). Price, 1 10 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 73 FIG. 80. FIG. 82. FIG. 83. 91. Wet and Dry Bulb Hygrometer with Wood or Zinc Scales, mounted in a Japanned Metal Case, suited for out-door use, the Greenhouse or Conservatory (fig. 82). Price, 14 92. * Ditto Ditto with Negretti and Zambra's Patent Porcelain Scale, in Japanned Case, as fig. 82. Price, 110 93. Mason's Hygrometer, portable brass-jointed tripod-stand and metal cover (fig. 83). Price, 3 3 94. Negretti and Zambra's Standard Dry and Wet Bulb Hygrometer, or Psychrometer (fig. 84), consists of two parallel Thermometers, as nearly identical as possible, mounted on a wooden bracket, one marked dry, the other wet. The bulb of the wet thermometer is covered with thin muslin and round the neck of the stem is twisted or tied, as seen in fig. 84*, conducting-threads of lamp-wick, or common darning- cotton, these pass down into a vessel of water, placed at such a distance as to allow a length of conducting-thread of about three inches ; the cup or glass being placed on one side, and a little beneath, so that the water within may not affect the reading of the Dnj Bulb Thermometer. In observing, the eye should be placed on a level with the top of the mercury in the tube, and the observer should refrain from breathing whilst taking an observation. The temperature of the air and of the evaporation is given by the readings of the two thermometers, from which can be calculated the dew point, Tables being furnished for that purpose with the instrument. The dry bulb thermometer indicates the temperature of the air itself ; while the wet bulb, cooled by evaporation, shows a lower temperature according to the amount of and rapidity of evaporation. This instrument is used by the Members of the British Meteorological Society, and supplied to them by Negretti and Zambra (fig. 84) Price 220 Glaisher's Tables for ditto 026 NEGRETTI AND ZAMBBA, HOLBOKN VIADUCT, E.G., FIG. 85. FIG. 84. 95. Wet and Dry Bulb Hygrometer for external Window use, with engraved Opal Glass or Porcelain Scales, mounted on a substantial and Ornamental wood and metal bracket, fitted with a clamping screw for setting the scale at any convenient angle for observation, as fig. 85. Price 2 10 and 330 96. Portable Wet and Dry Bulb Hygrometer, (fig. 86.) A most compact and convenient form of Hygrometer, invented by Negretti and Zambra, as a companion instrument to their Small Patent Maximum and Minimum .Registering Thermometers and Pocket Aneroid Barometer (figs. 26 and 61), pages 26 and 51. The Hygrometer, with stand and water cistern, is fitted into a neat Pocket case. Price . . . .220 Larger Standard size . 2 10 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 75 FIG. 81. FIG. 86. 97. Dines* Hygrometer. We notice this apparatus chiefly as a matter of record. It is fully described along with an account of some remarkable results obtained from its use by its inventor, George Dines, Esq., in the Journal of the Meteorological Society ; but, like Daniell's, Regnault's, and Jones's Hygrometers, it is not self-acting, and not so simple in its use as the Wet and Dry Bulb Instrument. Therefore, this Apparatus will only be supplied to special order. Price, 2 12 6 to 3 3 98. Registering Hygrometer, constructed with Negretti and Zambra's Patent Maximum and Minimum Registering Thermometers, each fitted up as a wet-bulb thermometer, to record the highest and lowest temperature of evaporation during any interval of time. Price, 330 99. Hygrometer Screen. The engraving (fig. 89), page 79, shows one of the best methods of fixing up and protecting the Hygrometer, the louvre boarded case affording free passage to the air and at the same time protection from rain, suow, the sun's rays, or radiated heat from surrounding bodies. This Screen should be fixed at about four feet from the ground, the door facing due North. If fixed against a wall, there should be left a space between the back of the Screen and the wall, at least three or four inches, to insure a free circulation of air. It need hardly be pointed out that the Screen must be securely fastened to its support, wherever used, to prevent vibration or injury from wind. This arrangement is specially recommended by the Board of Trade for Marine Service both for Hygrometers and Thermometers. Price, 1 1 0, or made to Order. 100. From the readings of the two thermometers, the dew-point can be deduced by formulae (that known as Apjohn's is considered the most theoretically true), or from the valuable Hygrometric Tables by J. Glaisher, Esq., F.R.S. 76 NEGRETTI AND ZAMBEA, HOLBORN VIADUCT, E.G., 101. For practical purposes in estimating the comparative humidity, the annexed table, which is a reduction from Mr. Glaisher's elaborate work, will be sufficient. Temperature by the Dry Bulb Thermometer. Difference between Dry-Bulb and Wet-Bulb Readings. 2 4 6 8 10 12 Degree of Humidity. 34 79 63 50 __ 36 82 66 53 __ 38 83 68 56 45 40 84 70 58 47 __ ___ 42 84 71 59 49 44 85 72 60 50 46 86 73 61 51 48 86 73 62 52 44 50 86 74 63 53 45 , 52 86 74 64 54 46 54 86 74 64 55 47 56 87 75 65 56 48 58 87 76 66 57 49 60 88 76 66 58 50 43 62 88 77 67 58 50 44 64 88 77 67 59 51 45 66 88 78 68 60 52 45 68 88 78 68 60 52 46 70 88 78 69 61 53 47 72 89 79 69 61 54 48 74 89 79 70 62 55 48 76 89 79 71 63 55 49 78 89 79 71 63 56 50 80 90 80 71 63 56 50 82 90 80 72 64 57 51 84 90 80 72 64 57 51 86 90 80 72 64 58 52 The total quantity of aqueous vapour which at any temperature can be diffused in the air being represented by 100, the percentage of vapour actually present will be found in the table opposite the temperature of the dry-bulb thermometer, and under the difference between the dry-bulb and the wet-bulb temperatures. The degree of humidity for intermediate temperatures and differences to those given in the table can be easily estimated sufficiently accurately for most practical purposes.* This table will be found serviceable to Horticultarists, since it will enable them to estimate the chilling effect of dew or hoar-frost on tender plants. In England the usual difference between the thermometer readings, in the open air, shaded from the sun, reflected heat, and currents of air, ranges from one to twelve degrees. In hot and dry climates, as India and Australia, the range out of doors has been found as much as 30. A. still more comprehensive but simple Dew-Point or Humidity Table has been recently published by William Marriott, Esq., F.M.S., price 6d. 45, CORNHILL, E.G., AND 122, REGENT STREET, W,, LONDON. 77 The Summer and Autumn of the year 1859 were specially remarkable for a most unusual Thermometric and Hygrometric condition of atmosphere, and Londoners will long remember the state of the River Thames during that period. Deficiency of water supply during 1858 and 1859, and great evaporation (often to fourteen degrees of thermometrical difference in Mason's Hygrometer), caused a condition of its stream excessively offensive, if not actually pestilential and unhealthy. Everywhere a want of water was felt, and this had been of considerable duration. In August the heat reached 92 (in places where usually summer heat is not above 80 Q ), and the temperature of evaporation was 78, by the same hygrometer. INSTRUCTIONS FOR THE USE OF THE WET AND DRY BULB HYGROMETER. 102. The muslin on the bulb of the Hygrometer should be washed occasionally by pouring water over the bulb ; and it should be replaced by a fresh piece at least once a month. Accuracy depends very much upon keeping the wet bulb clean, free from dust, and not too wet. When the bulb is frozen, some cold water should be taken from nnder ice, being cautious to raise its temperature as little as possible, and the thermometer bulb should be wetted with it by means of a camel-hair brush or feather. After waiting a few minutes, the temperature of evaporation may be observed. The water should be either distilled or rain water, or if this be not procurable, the softest pure water which can be had. The water vessel should be replenished after, or some little time before, observing ; because observations are incorrect if made while the water is either colder or warmer than the air. In connection with the barometer, the Wet and Dry Bulb hygrometer is very useful, not only on land, but especially at sea, where other kinds of hygrometers cannot be practically used. A fall in the Barometer is indicative of coming wind or rain ; if the hygrometer shows increasing dampness by the difference of the readings becoming smaller, rain may be anticipated. On the contrary, if the hygrometer shows continuing or increasing dryness, a stronger wind is probable, without rain. The Hygrometer is eminently useful in regulating the moisture of the air of apartments ; a difference in the thermometer readings of from 5 to 8 being considered healthy. Many diseases require that the temperature and humidity of the air which the invalid breathes should be very carefully regulated. In a room, the hygrometer should be placed away from the fire, but not exposed to draughts of air. 78 NEGKETTI AND ZAMBEA, HOLBOBN VIADUCT, B.C., FIG. 87. 103. Negretti and Zambra's Self-Kecording Hygrometer, fig. 87. The Thermometers in this Hygrometer are similar in construction to those used in Negretti and Zambra's Patent Hourly Recording Thermometric Apparatus. No. 64, Page 55. It will be seen by the drawing (fig. 87) that two Thermometers are, with a Water Cistern, mounted upon a metal frame in; such a manner that they will fall over and become inverted from the joint action of a Clock and Galvanic Battery. The most important improvement in this Self- Recording Hygrometer is that it can be freely exposed at any distance from the regulating clock. Our wood engraving exhibits the Clock, A, with an adjusting index upon its dial, enabling the observer to arrange the release of the detent, B, at any appointed time, thus allowing the frame supporting the Hygrometer to turn over, and by inverting the Thermometers record the temperature of both the Wet and Dry bulb instruments at the moment. The escapement is an Electro Magnet, seen at B, in connection with a Galvanic Battery, B, the Clock at C and C, and the Wire A and A. At the arranged time the circuit is completed by the clock, and the electrical current acting upon the soft iron magnet releases the detent and the Hygrometer turns over. The instrument is re-set for another observation, by turning back the frame with the Thermometers into its original vertical position (as shown in the engraving) and by adjusting the index of the Clock. Price 10 10 The peculiar construction of the two Thermometers is fully described on page 63, and fig. 71. 45, COKNHILL, E.O., AND 122, BEGENT STREET, W., LONDON. 79 FIG. 88. FIG. 89. FIG. 91. FIG. 90. 104 Screens for Thermometers and Hygrometers-. 80 NEGRETTI AND ZAMBRA, HOLBOEN YIADUCT, B.C., FiG. 92. 104. Beckley's Thermograph and Eecording Hygrometer.^ As recommended by the Meteorological Committee of the Boyal Society for pro- ducing Photographic records of the variations of temperature and moisture in the atmosphere. In the engraving (fig 92) the Wet and Dry Bulb Thermometers are shown at W and T. freely exposed to the external atmosphere, at H is a screw for adjusting these Thermometers ; C is an accurate clock for rotating the cylinder D (upon which is stretched the sensitised photographic paper) once in 48 hours ; G G are gas lamps, the rays of light from them being concentrated by two condensers, E E, upon reflectors M M and thence projected by the Photographic Combination Lenses P P, through perforated screens and the air bubbles in the tubes of the Thermometers upon the prepared paper. Upon the drum D the movements of the air bubble in both tubes are hereby recorded with precision, a screen in connection with the clock movement is arranged to intercept the light for 4 minutes every two hours, this producing white lines (time spaces) upon the paper when the record is developed. The room in which the Thermograph is placed should be most carefully darkened when the apparatus is in action. Price, 125, complete with two Standard Thermometers, two Bent Thermometers, Clock Movement, Sec., fyc.. complete, made to order. RAIN GAUGES 81 105. It is hardly possibly to over-estimate the value and importance of carefully compiled statistics of the Rainfall. The two great sanitary questions of the day, viz., the Water supply and Sewage of large towns, are in a very great measure connected with the amount of rain falling during a given period, and reliable particulars of the rainfall are specially valuable both to the Civil and Hydraulic Engineer. The Farmer and commercial Financier are also both deeply interested in the results of a probable dry or wet season influencing the growth, amount, and value of various crops and produce of the earth. We subjoin a few facts we think may prove useful and interesting. Fall of Rain at the Royal Observatory, Greenwich. Taking December, January, and February as the winter months ; March, April, and May as the spring months ; June, July, and August as the summer months ; September, October, and November as the autumn months, the quantities which fell in the different seasons were as follows : 1842. 1843. 1844. 1845. 1846. 1847, Mean. Winter . Spring Summer . Autumn . Inches. 2-81 4-42 5-69 9-65 Inches. 4-14 5-98 7-34 7-01 Inches. 5-16 359 6.63 9-58 Inches. 5-33 4-27 6-84 5-90 Inches 5-42 5-43 6-00 8-44 Inches. 4-77 3-16 4-12 5-56 Inches. 4-60 4-47 6-10 7-69 Total . 22-57 24-47 24-96 22-34 25-29 17-61 22-86 The quantity of rain which fell at the Royal Engineers' stations during the year 1853-4, was as follows : Edinburgh Guernsey St. John's Gibraltar Malta . Jamaica Inches. 23-15 32-77 55-05 47-29 28-08 34-31 Barbadoes . Ceylon Mauritius . Fremantle . New Zealand Inches. 68-24 71-63 39-52 33-94 48-42 Lincoln is the dryest recorded station in England, the mean annual rain- full being 20 inches. The wettest recorded station is Stye, at the head of Borrowdale in Cumberland, where the mean annual rainfall amounts to 165 inches. A fall of rain measuring a tenth of an inch in depth is equal to a deposit of about forty hogsheads per acre. 82 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, B.C., POSITION FOR RAIN GAUGES 106. From the observations made at the Royal Observatory at Greenwich, the fact is clearly established that in the lower regions of the atmosphere, the quantity of rain which falls diminishes with the altitude above the ground. The height for placing the receiving surface of a rain gauge is somewhat open to a difference of opinion. Mr. Glaisher's gauge is directed to be ** half sunk in the ground." This would place the edge of the gauge about 8 inches from the surface of the ground. Mr. Symons gives 12 inches as most correct, 10 inches as a mean between these will be perhaps the best to adopt. Rain gauges should be placed on a level piece of ground, and not on a slope or terrace, away from walls or trees, as many feet from their base as their height, the edge of the funnel should be set quite level. Unless for special observa- tions Rain Gauges should not be placed on roofs or any very elevated position. It is very important that Rain Gauges be occasionally examined to see that the Receiving Funnel be not choked up by dust or leaves, and that at very wet stations the receiving portion of this Gauge be sufficiently large to hold any possible rainfall ; even the probable occurrence of a water-spout might be provided for in hilly or very exposed situations. Gauges should be well supported to prevent their being knocked down or blown over by the wind, and after riow or frost the gauges should be placed in a warm room until the collected contents are melted and can be measured. In measuring off the quantity of collected rain, the graduated glass should be held quite upright, and the reading taken midway between the two apparent surfaces of the water. The rain should never be collected in the graduated measure, especially in winter, to avoid risk of breakage by frost. 107 Measurement of Rain. The Rain Gauge should be examined every day, at nine a.m., and the amount of water collected by it entered in the register, as having fallen on the previous day ; for if we measure at nine a.m. to-day, it is probable, under ordinary conditions, that more of the Rain collected by the Gauge will have fallen during the fifteen hours of the previous day up to midnight than during the nine hours extending from midnight to nine o'clock of the following morning. A vast amount of interesting and most valuable information respecting Rain Gauges and the Rainfall will be found in Negretti and Zambra's Treatise on Meteorological Instruments, and Mr. G. J. Simons' eminently useful publications as enumerated in our list of books at the end of this section. 45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 83 INSTRUMENTS USED FOR MEASURING THE RAINFALL FIG. 93. FIG 94. FIG. 95 108. Howard's Rain Gauge,* (fig. 93). The simplest form of the in- strument constructed 'and used by the celebrated meteorological writer, Luke Howard, from whom it derives its name ; it has a 5-inch Copper Funnel, with a turned brass Rim, fitted to a stoneware or glass bottle, with a glass graduated measure divided to hundredths of an inch. Price, 10 6 109. Symons' Rain Gauge, (fig. 94). This instrument has a glass receiving bottle protected by a metal case, with openings at the side for the convenience of observing the collected rainfall without disturbing the frame, which is firmly supported in the ground by strong spikes. The measure holds half an inch of rain for a 5-inch area subdivided into hundredths. Price, with graduated measure . . 10 6 Ditto, in Copper 15 See also Symons 1 Snorvdon Rain Gauge, No. 118, Page 85. 110. Glaisher's Rain Gauge, (fig. 96). This gauge is eight inches diameter, and arranged for the reception of the water only which falls upon its receiving surface, and for the prevention of loss by evaporation. The rain is first collected in a funnel, the receiving surface of which is accurately * Pluviometer, Ombrometer, Udometer. G 2 84 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, F.C., FlQ. 96. FIG. 97. turned in a lathe, and terminated at its lower extremity in a bent tube of small aperture, in which the last few drops of rain remain as shown in the engraving. The glass receiving vessel is graduated to hundred ths of inches according to the calculated weight of water, as determined by the area of the receiving surface. In use, the gauge is partly sunk below the surface of the soil, so that the receiving surface is about eight inches above it. Thus situated, no water escapes by evaporation in any month of the year. If placed differently, the readings must be taken daily. Price t in Japanned Tin . 1 1 in Copper . . 1 10 RECEIVING VESSEL FOE GLAISHER'S GAUGE. Price, in Japanned Tin or Copper, 2s. ^' e necessity of leaving snow, sleet, or hail, whenever they occur, in the Gauge until they can be melted ; the ordinary Gauge not being always capable of containing the amount of a long-continued fall of snow. This apparatus was contrived by Mr. R. Bent-ley, at Upton (near Windsor), for use in connection with an 8-inch Guage situated on a roof inaccessible under ordinary circum- stances. On reference to the accompanying diagram, it will be seen that the distinguish- ing feature of this Gauge is the melting of any snow or sleet immediately on its reception. This arrangement makes it very useful in connection with any automatic registering apparatus, or where the Gauge, from its posi- tion, is not easily accessible, and at night. The action of the Gauge is briefly thus : The rain or snow fall is received in the usual 8-inch funnel, from the bottom of which it falls by gravity to the end of the tube (of whatever length that may be) without touching the sides. This is a very important point, and is gained FIG 102. ky fitting a short guide-pipe, of some six inches in length, to the bottom of the funnel, and by the internal diameter of the long tube being gradually slightly increased in proportion to the length of the tube. At the bottom of the tube (which is within the house) is placed a tap and measuring-glass. If preferred, the tap can be left open or removed, and an automatic recording apparatus substituted. By the side of the main tube, but sufficiently distant from it for any heat not to be conveyed sideways, is the melting tube. The hot air is furnished by a gas jet or lamp or even a candle or night-light and being regulated to a 45, COBNH1LL, E.G., AND 122, REGENT STREET, W., LONDON. 89 temperature of from about 40 to 46 Fahrenheit, by the thermometer enclosed in the tube (and exposed to view by means of a piece of glass inlet), ascends through the funnel, and gradually melts the snow, etc., as it falls in. Too high a temperature should not be employed, as being conducive to evaporation. An additional protection may also be afforded by the employment of a self- acting valve midway in the heating tube, to expand with any access of heat, in so doing partly to close the way, and at the same time to push open a small trap-door, letting out some of the hot air and admitting some cooler air from the outside. As soon as the proper temperature has been by this means restored, the valve would contract into its normal position. This arrangement, however, owing to the delicacy of the adjustment, is very apt to get out of order. Messrs. Negretti and Zambra construct the above apparatus to order ; but no exact prices can be quoted, as the cost would vary greatly according to the extent and nature of the work and the position in which it is to be placed. A small piece of very open wire- work might be placed across the receiver, halfway down, in case of leaves, &c., falling in. In the construction of the Gauge, Copper should be employed. 124. Marine Bain Gauges. Negretti and Zambra have constructed several different forms of Rain Grange for use on board of ship. One arrange- ment having gimbal mountings similiar to a steering compass has been found the best, but the records obtained by their use at sea have been unsatisfactory and not considered of any scientific value. EVAPORATION. 125. Mr. R. H. Scott, of the Meteorological Office, writing on this subject, remarks that it "is one of very great importance, especially as regards its connection with Rainfall and Water supply, and well deserves especial atten- tion ; but it cannot as yet be said that the results hitherto obtained merit much confidence as regards their applicability to the evaporation occurring in nature, owing to the exceptional manner in which the observations have been made." Atmometers of many forms have been invented and constructed, both in this country and on the Continent, but, at present, nothing satisfactory has been devised ; hence the difficulty of making any very accurate observations in connection with evaporation from the surface of water. 126. Evaporation Gauge, (fig. 103), (Evaporometer), for showing the amount of evaporation from the earth's surface. This gauge consists of a brass vessel, of eight inches diameter, corresponding with Glaisher's Gauge, the area or evaporating surface of which is accurately determined ; and also a glass cylindrical measure, graduated into inches, tenths, and hundredths of inches. In use, the Evaporating Gauge is nearly filled with water, the quantity having been previously measured by means of the glass cylinder ; it is then placed out 90 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.G. FIG. 103. FIG. 104. of doors, freely exposed to the action of the atmosphere ; after exposure, the water is again measured, and the difference between the first and second measurement shows the amount of evaporation that has taken place. If rain has fallen during the exposure of the evaporating dish, the quantity collected by a rain gauge must be deducted from the amount of the measured contents of the evaporating dish when the observation is made. The wire cage round the gauge is to prevent animals, birds, &c., from drinking the water. Price, with Graduated Measure . . : 136 127. Atmidometer* (Dr. Babington's), fig. 104 for measuring the evapo- ration from water, ice or snow. Consists of an oblong hollow bulb of glass or copper, beneath which, and communicating with it by a contracted neck, is a second globular bulb, duly weighted with mercury or shot. The upper bulb is surmounted by a small glass or metal stem, having a scale graduated to grains and half-grains ; on the top of which is fixed horizontally a shallow metal pan- The bulbs are immersed in a vessel of water having a circular hole in the cover through which the stem rises. Distilled water is then gradually poured into the pan above, until the zero of the stem sinks to a level with the cover of the vessel. Thus adjusted, as the water in the pan evaporates, the stem ascends, and the amount of evaporation is indicated in grains. This instrument affords * M r. Scott suggests that Leslie's term Atmidometer is more classically correct, but that Atmometer has the advantage of being shorter, without being absolutely incorrect, 45, COBNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 91 a means of measuring evaporation from ice or snow. An adjustment for temperature is necessary. Price, 220 Ditto, large size with Copper Tank 3 10 128. Glaisher's Thermometer Stand (fig. 91). The Thermometer Stand consists of a horizontal board as as a base, of a vertical board projecting upwards from one edge of the horizontal board, and of two parallel inclined boards, separated from each other by blocks of three inches in thickness con- nected at the top with the vertical board, and at the bottom with the horizontal board, and the air passes freely about and between all these boards ; on the top of the inclined boards is a small projecting roof to prevent, as much as possible, the rain or snow falling on the bulbs of the instruments which are mounted on the front of the vertical board. The bulbs of the Thermometers, &c., all project below the edge of the vertical board, in order, that the air may pass freely over them from all directions. The whole frame is constructed to revolve on an upright post firmly fixed to the ground, as .shown in the engraving; and in use, the inclined side should always be turned towards the sun. Price, . . . 330 129. Stevenson's Thermometer Screen, shown in fig. 90. The louvres in this arrangement are double, sloping in opposite directions, so that whilst there is free access of air to the interior, the radiant heat and rain are excluded. This form of Screen is now found to be the best of any yet invented, for climates similar to the British Islands ; but is not suitable for climates subject to great extremes, such as India or Canada. This Screen should stand on open ground and be strongly supported, not under the shadow of trees or houses, and at least twenty feet from any wall, and the floor of the screen to be about four feet above the ground. The door of the Screen should face due north. Price . . . 330 130. Negretti and Zambra's Set of Standard Instruments on a Screen. Includes N. and Z's. Patent Standard Maximum Registering Thermometer, Standard Minimum Registering Thermometer, and Standard Wet and Dry Bulb Hygrometer, Mounted on Mahogany Board. fig. 88. 550 Kew Certificates for above ... 10 The best position for placing the Thermometer Board or Screen is facing the North, at about five feet from the ground, supported firmly to prevent vibration from wind and away from all walls or trees, or if this board be supported by a wall it should be well blocked out from it at least 8 or 12 inchea to allow a free current of air to circulate behind it. NEGEETTI AND ZAMBEA, HOLBORN VIADUCT, E.G., 131. Apparatus for Determining Elevations by the Temperature of the Boiling-point of Water. The Barometrical Thermometer, or Hypsometrical Apparatus, is an improved form of Wollaston's Apparatus constructed by Negretti and Zambra, to meet the requirements of travellers in circum- stances where the mercurial barometer cannot be conveniently employed. The instrument is very portable, and affords a ready and accurate means of measuring heights. The apparatus is shown in section (fig, 105). It consists : First, of a very sensitive thermometer, about 12 inches long, the scale ranging from 180 to 212, having each degree subdivided so as to show distinctly 1. Secondly, a metal boiler (c) mounted on a small tripod stand; from the boiler proceeds three double tubes (E E E) and (D D D), open at the top ; screwed on the top of the boiler ; the outer tube has two openings, one at the top, through which the Thermometer (E E) is inserted, passing down to within an inch of the water in the boiler, and supported by means of an india-rubber washer, as shown in tig. 105 ; the second opening forming an outlet for the steam, as shown at (G). These double tubes are now constructed to separate at the joints by a simple slide fitting, so that any length of the Thermometer Stem can be made visible varying with the elevation at which the tubes are adjusted. The object of the double tube is to ensure a steady boiling- point, in which it would be impossible to obtain in open air- experiments, were only a single tube employed. (A) is a metallic spirit lamp, surrounded with wire gauze (s) to pre- vent the flame being extinguished when experimenting in the open air.* The whole instrument when packed in a leather case for travelling is shown in fig. 105*. Each instrument is FIG 105*. furnished with a carefully computed set of tables, from which may be obtained, by an easy calculation, the elevation corresponding to any observed boiling-point between the temperatures of 180 and 212. FIG. 105. * A Russian spirit furnace, surmounted by a small spirit lamp, is sometimes furnished. The object of the Russian furnace is to cause the water to boil rapidly ; when that has been accomplished, the small lamp is lighted, and placed over the blast from the furnace, which it extinguishes, at the same time its flame is sufficient to keep the water boiling. 45, COKNHILL, E.G., AND 122, EEGENT STREET, W., LONDON. 93 To use the Boiling Point Apparatus, it is simply necessary to pour into the boiler, through the small opening (F) on its surface, a sufficient quantity of water to fill it about one- third, and afterwards close it by means of the screw for that purpose ; the lighted spirit lamp is then applied, and when the water is made to boil, the steam rises, surrounding the bulb and tube, and descending between the two tubes, issues from the opening at (G.) After a few seconds, the mercury in the thermometer will rise and become stationary ; the degree indicated by it must then be noted, when, by reference to the tables, the elevation of the spot where the experiment has been performed may be obtained. The Temperature of the Air should be observed by a reliable Thermometer at the same time. Price, with Spirit Lamp, in Sling Case, 550 Extra Standard Thermometer . 1 10 Extra Thermometer for Air Temperature . 10 6 The following table expresses very nearly the elevation in feet correspond- ing to a fall of 18 in the temperature of boiling water : Boiling Temperatures Elevation in Feet between for each Degree. 2H Q and 210 520 210 and 200 530 200 and 190 550 190 and 180 570 Mule for computing heights from observations rvith the Boiling Point Apparatus or Mountain Thermometer, by Negretti and Zambrd's Boiling Point Tables. From Table I. take out the heights in feet corresponding to the boiling-points observed at the upper and lower stations respectively. The difference between these two numbers, multiplied by the factor in Table III. for the mean temperature of the air, is the difference in height required. EXAMPLE : At upper station, boiling-point = 187'3 ; temp, of air = 26. At lower station, boiling-point = 210 -4 ; temp, of air = 68. Boiling-point = 187'3 ; height from Table I. = 13495 feet. Boiling-point = 210 4 ; height from Table I. = 905. Difference =12590 Mean temp, of air = 47 ; factor from Table III. 1-033. Kequired difference between the two stations = 12590 X 1'033 = 13005 feet. To determine a height with accuracy, it is necessary that pure water should be used, distilled water if possible, and a similar observation should be made at the same time at a lower station, not very remote laterally from the upper, and both should be many times repeated. When such observations have been very carefully conducted, the height of the upper station above the lower may be ascertained with great precision, as has been repeatedly verified by subsequent trigonometrical measurement of elevations so determined. If the lower station be at the sea level, the absolute height of the upper is at once obtained. NEGRETTI AND ZAMBKA, HOLBOBN VIADUCT, E.G., FlG. 106. 132. Negretti and Zambra's New Pocket Boiling-Point Apparatus, (fig. 106) consists of a small globular metal boiler, mounted upon a metal sup- port or stand. In the base of this stand is formed a receptacle for holding and burning spirits of wine, by which water in {he boiler is rapidly heated up to the boiling-point. On the top of the boiler is a tube for the escape of steam during the operation, and on one side is seen another tube (horizontal), into which is inserted one of Negretti and Zambra's Patent Maximum Registering Thermometers, very finely and carefully divided upon its stem, of sufficient range for all possible elevations to be ascertained by the boiling-point of water. The boiler having been charged with a small quantity of water, and the receptacle filled with sufficient spirit, the boiler is placed upon its support above the burning alcohol, with the Thermometer bulb inserted into the side tube. In a few minutes the boiling point will be attained, and the mercury in the Thermometer will rise to this point, and remain in the tube until it is convenient to note the temperature thus obtained. If, after the experiment has been made, the Thermometer be carefully withdrawn from the boiler, and carried with the ~bulb-end uppermost, the record of the temperature may be read off hours, or even days, afterwards. The advantages of this apparatus are great simplicity, rapidity in use, and portability. Price, in a portable case, with an extra Thermometer for Air Temperatures, 300 133. Pocket Hypsometric Apparatus, as constructed by Negretti and Zambra for Dr J. D. Hooker, of a very simple and conveniently portable form, with one corrected Thermometer. Suited for rough exploring expeditions. 2 10 45, CORNHILL, E.G., AND 122, EBGENT STREET, W., LONDON. 95 APPARATUS EMPLOYED FOR REGISTERING THE DIRECTION, PRESSURE, AND VELOCITY OF THE WIND- FIG. 107. THE records obtained by the use of various forms of Anemometers are equally interesting and valuable. The amount of pressure and velocity of the wind are now registered with such precision, that it enables Millwrights and Engineers to make their calculations and arrange their machinery in accordance with the amount of work required to be done, and also to test and compare the expected with the actual results. Meteorologists are equally interested in Anemometer records. The points of direction and the duration of the wind in particular quarters and seasons have very much to do with the Rainfall and Evaporation in different countries and localities. The late Admiral FitzRoy in his Weather Manual repeatedly indicates the great importance of careful observations on the various phenomena of the wind in connection with Marine and Sea Coast Meteorology. 134. Wind Vane, for indicating the direction of the wind. See next page. It is important to note that the North point of the Vane should be carefully adjusted to the Geographical or true North, and not to the Magnetic North. See Compass Variations in Appendix at the end df the volume. 135. Anemoscope. Dr. Halleur's Portable Wind Vane and Magnetic Compass, for showing the direction of the wind to half a point of the compass. This instrument is very similar in form and size to Lind's Wind Guage, shown on page 98. Fig 109. Price 250 WIND VANES, FOB INDICATING THE DIRECTION OF THE WIND. FIG. A. FIG. B. 136. NEGRETTI & ZAMBRA construct Wind Vanes of various dimensions and designs to suit the positions in which they are to be placed, the cost varying with the amount of work and ornament upon them. As Fig. A. 2 feet 3 inches high . .150 5 feet . . . ..3126 As Fig. B. 4 feet high . . . .330 5 . . . . 4 12 6 As Fig. C. 3 feet high . . . 250 6 . . . . 550 These prices do not include fixing, for which special estimates will be furnished. These Vanes are japanned in plain colour Black, Red, Yellow or Blue. Gilding the Vane and Arrow extra, 14/6. Gilding the Direction Letters, 14/-. N. & Z., fit up Wind Vanes arranged to show the varying direction oi the Wind upon a Dial in the interior of Mansions or Public Offices. The cost for erecting such Wind Indicators depending much on the height of the building, and the position in which the Vane is to be placed, no positive prices can well be quoted ; estimates given upon particulars being sent. Wind Vanes ore frequently fitted upon buildings in connection with Lightning Conductors, particulars will be found in another section. 45, COKNHILL, E.G., AND 122, EEGENT STREET, W., LONDON. 97 FIG. 108. 137. Wegretti and Zambra's Improved Pendulum Anemometer invented by Dr. Prestel to exhibit at any moment in a most simple manner the direction and comparative pressure of the wind. By the action of the peculiar shaped vane A, the surface of the swinging pressure plate, B, is always kept facing the point from which the wind is blowing, and consequently exposed to its influence. During a calm the pendulous plate, B, will hang quite vertical in a line with the axis of the vane plate indicating zero or calm. As the wind increases in force the pressure indicator will be raised to various points between 1 and 10 of the vane. The holes are drilled through the plate of sufficient size to be plainly visible at a considerable height from the ground ; and to facilitate the reading, the 5 and 10 are of a larger conical form, so that the position of the pressure plate can be quickly observed. The subjoined table gives in English and French measures the value of the indications. The Metrical scale is calculated to show the pressure of wind in kilogrammes on the square meter, and the English scale pounds on the square foot. I. II. Scale of P. A. Pressure in Kilgr. on S. M. Manheim Scale. Elevation of Pendulum. Description of Wind. Pressure in Ibs. on the Sqre. foot. 0. Calm. ^ 1. 1 0-5 5 Gentle motion of air. 0-2044 cS 2. 4 1-0 20 Light breeze. 0-8176 I 3. 9 1-5 35 Fresh (top gallant W.) 1-8396 *- 4. 15 2-0 45 Stiff (strong top gallant W.) 30660 a 5. 25 2-5 54 Very Stiff breeze (top sail W.) 5-1110 P CO 6. 36-8 3-0 60 Strong rushing W. (to house top git.) 7-5119 C 7. 49 3-5 64 Stormy W. (to house top sails.) 10-0156 8. . 64 4-0 67 Gale of Wind. 13-0816 9. 81-6 4-5 69^ Strong Gale. 16-6790 10. 100 5-0 70 Hurricane. 20-4408 143-6 74 29-3518 98 NEGEETTI AND ZAMBRA, HOLBOEN VIADUCT, E.C., Negretti and Zambra think this Anemometer will meet a want often expressed to them, viz., a simple self-acting Wind-gauge ; for with very little more mechanical combination than a common direction vane, the Pendulum Anemometer will give sufficiently accurate results for unscientific observers. It has also the advantages of extreme simplicity, for beyond a little oil to the moving parts and an occasional coat of paint for protection, it does not require the least attention. Price, fig. 108, 660 The simplest mode of mounting this Anemometer is to fib it on the top of a flag-staff or mast 30 to 40 feet high, well sunk in the ground, strengthened and supported by three or four wire rope stays, attached to small sunk posts in the earth ; these wire ropes might be used as Lightning Conductors. Arms with the letters N. E. S. and W. to show the direction of the wind as on fig. A page 96 can be placed on the mast below the Anemometer. 138. Lind's Anemometer or Wind Gauge (fig. 109), invented in the year 1775, for observing the pressure of the wind, con- sists of a glass syphon, the tubes are parallel to- each other, and each tube is of the same diameter. One end of the syphon is bent at right angles to the general direction of the tubes, so as to present a horizontal opening to the action of the wind. A graduated scale, divided to inches and tenths, is attached to the syphon tube, reading either way from a zero point in the centre of the scale. The whole instrument is mounted on a spindle, surmounted by a vane, and is moved freely in any direction by the wind, always presenting the open end of the tube towards the quarter from which the wind blows. To use the instrument it is simply filled up to the zero point with water, and then exposed to the wind; the difference in the level of the water gives the ,force of the wind in inches and tenths, by adding FIG. 109. together the amount of depression in one limb, and elevation in the other, the sum of the two being the height of a column of water which the wind is capable of sustaining at that time. At the base of the instrument is a brass plate, upon which are engraved the principal points of the compass, for indicating the direction of the wind. Price, 220 The bend of the syphon is contracted internally to diminish the jumping movement of the water produced by sudden gusts of wind. 45, CORNHILL, E.C., AND 122, REGENT STREET, W., LONDON. 09 No. 139. Negretti and Zambra's Registering Lincl's Anemometer. Several modifications of Lind's Wind Gauge have at various times been in- vented by Sir W. Snow Harris, Mr. Wood and others, with a view to make ifc self-recording, but the only one that proves satisfactory in actual service, is an arrangement manufactured by Negretti and Zambra at the suggestion of Mr. Forbes, of Inverness. The improvement consists of a third tube of the same internal diameter, connected by a bend at the Zero point of the instrument, into which the water overflows and is collected from the leeward tube of the syphon. The water thus collected being the maximum amount of depression produced in the syphon representing the extreme force of the wind. Table showing the Force of wind on a square foot, for different heights of the column of Water in Lind's Wind-Gauge. Inches. Force in Ibs. Common designation of such Wind. 6 31-75 A Hurricane. 5 2604 A violent Storm. 4 20-83 A great Storm. 3 15-62 A Storm. 2 10-42 A strong Wind. 1 5-21 A high Wind. 5 2-60 A brisk Wind. 1 52 A fresh Breeze. 05 26 A gentle Breeze. o- 0' A Calm. Price, 330 140. Improved Portable Air Meter, for measuring the velocity of currents of Air in Coal Mines and Ventilators, Flues, &c., of Public Buildings, Hospital and Prison Wards, &c., &c. (figs. 110 and 111.) By means of this Air Meter, the rate at which a current of Air is moving can be ascertained in a few minutes. The Instrument shows from one foot to ten million feet. The long hand marks up to 100 feet ; each division on the large circle represents one foot traversed by the current of air. In setting down a reading of the hands, the long hand takes the units and tens places. The five other hands follow respectively. EXAMPLE. Millns. 100 thds. 10 thds. thds. hds. long hand. Places the hands take when set down in figures 00|0|0|OjO|00 Reading of the above diagrams ... 1 | J 9 | 9 99 In setting down the position of the hands observe the following rule : No hand can mark a figure unless the foregoing hand has arrived at the " 0." For example, suppose the long hand pointed to 99, the hundreds' hand would appear to point to a figure, but it could not mark the figure until the long hand pointed to the zero. The same rule applies to all the hands. When a hand appears to be between the divisions, write down the lowest figure next the hand. The catch on the rim of the instrument will stop or allow the hands to run without affecting the action of the fans. 100 NEGBETTI AND ZAMBRA, HOLBORN VIADUCT, E C., FIG. 110. FIG. 111. The above engraving of the Dial is the exact size of the Dial of the Instrument. The Meter may be fi^ed in the current on a rod, fitted into the socket, which screws into the bottom of the instrument. To take a measurement fix the position of the hands (by moving the catch) write down the reading, and place the Meter in the current of air to be measured. Now put the hands in action by again moving the catch at the same moment, note the time by the second hand of a watch, allow the fans to run in the current for one minute, at the end of which time again put the hands out of action, and again read their position, subtract the first reading from the second, and the result gives the velocity of the air in feet per minute (unconnected). The Meter may be allowed to run ia the current of air for any convenient length of time ; but, if for longer than one minute, the difference of the first and second readings must be divided by the number of minutes of the running. This gives the (uncorrected) velocity of air for one minute. A table is supplied with each instrument, showing the necessary correction for friction, &c., at various velocities per minute. In the -second column of this table will be found the correction (opposite the velocity shown by the Meter in the first column). This correction' if applied to a measurement of more than one minute, must be multiplied by the number of minutes of the measurement, and added to or subtracted from (according to the sign) the difference of the two readings, EXAMPLE. Suppose the first reading to be . And the second after a running of ten minutes is 5260 11060 5260 The running per minute would be . . , . Say the correction for 580 shown by the meter per minute is The real or corrected velocity per minute would be 580 82 662 45, CORNHILL, E.G., AND 122, EEGENT STREET, '\V., LONDON. 101 And the real velocity during the running of ten minutes is 6620 feet. The measurement of the current of air in feet per minute, divided by 88, will give the measurement or velocity in miles per hour. NOTE. In taking a measurement the fans must always face the wind, and care should be taken not to bend or injure them. Price of the Improved Air Meter in a neat Box, figs. 110 and 111 440 141. Lowne's Patent Colliery Air Meter constructed expressly for use in Coal Mines or Air Shafts. The improvements consists of 1st, a large clear Dial; 2nd, the Fan is con- structed of a light and anti-corrosive material ; 3rd, the Indicating parts are perfectly pro- tected from dust and smoke (this is done by a practical mechanical arrangement) ; and, 4th, a Lever is placed in a convenient position, to enable the observer to throw the Indicating "Wheels in or out of gear from the Fan, for the purpose of taking short ^observations with accuracy-, 6-inch Air Meter, as fig. 112, Price, 4 10 FIG. 112. INSTRUCTIONS FOR USINO THE IMPROVED AIR METER. Press the Lever home to the left hand, and the Fans will revolve without moving the Registering Works. Now take a careful reading of the instrument, and write it down ; hold the Air Meter in the current by the ring at the top of the Instrument ; allow the Fans to run freely for a short time. Now observe the Watch. When the Second Hand reaches the Minute, press the Lever to the right, and the works will be in gear. When the minute is up, again press the Lever to the left hand, to throw the works out of gear ; take a reading of the dial and write it down above the first reading, subtract the first reading from the second, and the difference, after the correction is added, will be the velocity of the current in feet per minute, thus : Second Reading 9,260 First Reading . 8,920 Add Correction, say Rate of current 340 40 380 feet per minute. For measuring currents for a longer space of time, the Air Meter should be suspended on a bar, or fixed in any convenient manner in the current. The Fans must always face the current, and great care should be taken never to stop them suddenly. 102 NE'GfefcTTl AND ZAMBEA, HOLBOKtf VIADUCT, B.C., NOTE. -Any one not familiar with Metric Dials must observe that the figures read rationally : thus, if the feet hand is at, say, nine, the tens hand will be near the figure it is approaching. This figure must not be taken, but the previous one that is passed. Table showing the number of miles per hour at velocities per minute. Feet per Minute. Miles per hour. Feet per minute. Miles pei hour. Feet per minute. Miles per hour. 10 113 200 2-272 3,000 34-090 20 227 300 3-409 4.000 45-454 30 340 400 4-545 5,000 56-818 40 454 600 5-681 6,000 68-181 50 568 -600 6-818 7,000 79-545 60 681 700 7-954 8.000 90-909 70 795 800 9-090 9,000 102-272 80 909 900 10-227 10,000 113-636 90 1-C22 1,000 11-363 100 1-136 2,000 22-727 " When inquiring into the causes of air currents, either from or within drains, it was suggested that the variable flow of sewage has a powerful influence on the air within the drain, whilst that produced by rainfall has still greater, and the variations of temperature are another cause of displacement and renewal of drain air. A series of observations were taken at the outlets of drains by the Anemometer at the point of connection with the sewer, and the results proved that up and down currents of air are constantly passing to and fro. Whenever an up-current issues through a drain-opening it must be manifest that some of the inlets of such drains are untrapped. and therefore sewer air must be escaping through such untrapped inlets, to the danger of those who reside in the house." 142. Biram's Anemometers, for registering the velocity of currents of air in mines, &c., by means of a light vane, the revolutions of which are recorded npon a dial in the centre of the instrument. 12-in., 5 0; 6-in., 4 0; 4-in., 3 3 0; 2J-in., 2 10 These Anemometers will register the velocity of Air through any passage of a Mine or Air Shaft in which they are placed. 'For the purpose of trying and regulating the proportions of Air to the several divisions of a mine, and for the convenience of Overlookers, the three small instruments, 6 inches, 4 inches, and 2J- inches, are recommended. These sizes will also be found convenient for use in large gun or rifle practice. To ascertain the rate at which air is moving, proceed thus suppose 100 revolutions=200 feet per minute. 88] 200 [2^27. Say 2J miles per hour 88 being l-60th of a mile. To find the force of Wind, multiply the square of the velocity of the wind in feet per second by "0023. NOTE. The velocity of the wind in feet per minute, divided by 88, will give the velocity in miles per hour. (See above example.) 45, COBNHILL, E.C., AND 122, REGENT STREET, W., LONDON. 103 143. New Self-Timing Anemometer (Patent). This improved instrument dispenses with the use of a watch. By hold- ing the Anemometer in the current of air to be measured for a few seconds it will correctly indicate its velocity per second. Price, tig. 113. 500 , INSTRUCTIONS FOR USE. This instrument is held up with its back facing the current of air to be measured. When the . 113. vanes have revolved for a few seconds, press the spring button at A, the large hand then indicates feet per second. When read release the spring button. Should the velocity be such that the hand travels more than one revolution, then read the inner circle of figures. The small hand shows whether the outer or inner circle should be read. NOTE. As every instrument is graduated at each unit by actual experiment^ no allowance has to be made for friction. Feet per min. Feet per sec. Miles per hour. Force in Ibs per square foot. Description. 50 83 568 0016 Hardly perceptible. 100 200 1-66 3-33 1-136 2-272 0061 0255 1 Just perceptible. 300 4-99 3-408 0574 ) 400 666 4-544 1021 > Gentle breeze. 500 8'33 5-680 1595 ) 750 1000 12-50 16-66 8-522 11-363 3593 6388 i Pleasant breeze. 2000 33-33 22-726 2-5553 Brisk gale. 3000 49-99 34-089 5-6982 High wind. 4000 66-66 45-452 10-2214 Very high wind. 5000 83-33 56-815 16-4429 Storm. 6000 99-99 68-178 22-9954 Great storm. 7000 116-66 79-541 31-3019 8000 9000 133-32 149-99 90-904 102-267 40-8807 51-6920 Hurricane. 10000 166-66 113-630 60-8837 104 KEGRETTI AND ZAMBEA, HOLEOBN YIADUCT, E.G., FIG. 114. 144. Robinson's Anemometer. Dr. Robinson, of Armagh, is the inventor of this very useful anemometer, for determining the horizontal velocity of the wind. It was first used in 1850, in the meteorological and tidal observations made on the coast of Ireland under the direction of the Rev. Dr. Lloyd. It is represented in its simplest form by fig 114. Four hollow hemispherical cups AA, are extended upon strong metal arms, with their concave services facing the same way upon a vertical axis, B, which has at its lower extremity an end- less screw, D. The axis is supported and strengthened at (7, and constructed so as turn with as little friction as possible. The endless screw on the vertical shaft is placed in gear with a train of wheels and pinions. Each wheel revolves past a fixed index, and the figures and graduations are marked upon the wheels themselves. The readings on the dials of the Anemometer are as follows : one complete revolution of ihe first engraved index- wheel equals -^ of a mile; the second, I mile ; the third, 10 miles ; the fourth, 100 miles ; the fifth 1,000 miles ; neces- sarily in noting such reading it must be done backwards, according to the indications on the instrument. Dr. Robinson has proved by theory and experiment that the centre of any one of the cups mounted as fig. 114 revolves with one-third of the wind's velocity. Therefore allowance has been made for this in graduating the circles, and a true reading is at once obtained. Price, fig. 114 3 3 and 440 145. Robinson's Anemometer. Negretti and Zambra's improved arrangement for recording the velocity of the wind, as described by Colonel Sir H. James, Royal Engineers. This is a modified form of the Robinson instrument previously described, our engraving (fig. 115) will show the general details of the mechanism. . It consists of four arms at the end of which there are four light hemis- pherical hollow metal cups, the concave surfaces facing in one direction and revolving with one-third of the velocity of the current of wind acting on them. On the vertical axis which carries the arms, there is an endless screw, which communicates its real velocity of rotation to a circular dial. 45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 105 V FIG. 115. This Anemometer is furnished with two graduated circles, the outer one being divided into five miles and tenths of a mile, and each division on the inner circle represents five miles. One revolution of this circle recording from five to five hundred and five miles. The fixed pointer or index recording on the outer circle miles and tenths of a mile to five miles ; and the moving index records every five miles up to five hundred. If for example the movable hand stands between 15 and 20 on the inner circle, and the fixed hand indicates 3 miles and five-tenths the length of the current of air which has passed the station is equivalent to 18 miles and five-tenths. The velocity of the wind at any particular moment is found by observing the index before and after a certain interval of time as one or five minutes, and then multiplying the rate by 60 or 12 to find the velocity in miles per hoar. The pressure in Ibs. per square foot can then be ascertained by reference to tables mentioned in our list of books at the end of this Section. A mill-headed screw at the back of the instrument (fig. 89) turns the movable index, which should be brought back to zero after the observation is registered. Price, fig. 115, 4 10 The Anemometer frame is arranged for screwing on the instrument to a firmly-supported post. 146. Robinson's Anemometer, (fig. 116). This drawing shows a further improvement in the recording movement, a second dial being added for the convenience of obtaining extended readings. The left hand dial of this Anemometer is divided and figured exactly the same as in the previously described instrument, and the indications read off in a similar manner. The second dial has 10 divisions, each of these divisions being equal to 505 miles, which is sub-divided by the readings of the left hand dial. Price, fig. 116, 6 15 106 NEGBETTI AND ZAMBEA, HOLBOEX VIADUCT, E.G., FIG 116. 147. Robinson's Anemometer, mounted in gimbals for Marine Service. This instrument not having been found of much practical value will only be made to order. Robinson's Anemometers should be fixed in an exposed situation, as high above ground as may be convenient for reading. It can be made very portable by having the arms which carry the cups being fitted to unscrew or to fold down. 148. Whewell's Self-registering Anemometer, for recording the amount of horizontal movement in the air, with the direction, for twenty-four hours. A full description of this Anemometer will be found in Negretti and Zambra's Treatise on Meteorological Instruments. It is now rarely used, Osier's and Beckley's arrangements having been found more practically useful. Price, 25 Any of these Anemometers can ~be supplied metrically divided if desired. 149. Osier's Self-registering Anemometer and Rain Gauge (fig. 117). This improved arrangement of Anemometer was shown by Messrs. Negretti and Zambra at the International Exhibition, 1862, having Robinson's Cup Anemometer added to it, so that the pressure and velocity appear on the same sheet on which a line, an inch in length, is recorded at every 10 miles. The Improved Anemometer shows the Direction, Pressure, and Velocity of the Wind, also the amount of Rainfall upon one Sheet of paper. Our woodcut is not given as an actual working drawing of Osier's Anemometer, but simply to exhibit the relative position of its several parts. The mechanism may be variously modified, but the following is a description of the most recent and improved arrangement. 45, COBNHILL, E.G., AND 122, EEGENT STREET, W., LONDON. 107 FIG, 117. Osier's Self-registering Anemometer and Rain Gauge. Osier's instrument (fig. ] 17) consists of the vane, V 9 of a wedge-shaped form, which is found to answer better than a flat vane ; for the latter is always in a neutral line, and is therefore not sufficiently sensitive. At the lower end of the tube, 2T, is a small pinion, working in a rack, r, which is moved backwards 108 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, B.C., and forwards as the wind alters the position of the vane. To this rack a pencil, #, is attached, which marks the direction of the wind on a ruled paper, placed horizontally beneath, and so adjusted as to progress at the rate of half an inch per hour, by means of a simple contrivance connecting it with a clock, which carries the registering paper forward by one of the wheels working into a rack attached to the frame. The paper is shown in the illustration upon the table of the instrument. The pressure plate, F, for ascertaining the force of the wind, is one foot square, placed immediately beneath the vane ; it is supported by light bars, running horizontally on friction rollers, and communicating with springs, 1, 2, 3, so that the plate, when affected by the pressure of the wind, acts upon them, and they transfer such action to a copper chain passing down the interior of the direction tube, and over a pulley at the bottom. A light copper wire connects this chain with a spring lever, y y, carrying a pencil which records the pressure upon the paper below. Mr. Osier prefers a spring to any other means for ascertaining the force of the wind, because it is of the highest importance to have as little matter in motion as possible, otherwise the momentum acquired will cause the pressure plate to give very erroneous indications. The pressure plate is as light as is consistent with strength. It is kept before the wind by the vane, and is urged out by three or more springs, so that with light winds one only is compressed, and two, or more, according to the strength of the wind. The pluviometer is placed on the right in the figure, PP being the plane of the roof of the building. The rain funnel, R, exposes an area of about two hundred square inches. The water collected in it is conveyed by a tube through the roof of the building into a glass vessel, (?, so adjusted and graduated as to indicate a quarter of an inch of rain for every two hundred square inches of surface, i.e., 50 cubic inches. is supported by spiral springs, b b, which are compressed by the accumulating rain. A glass tube, open at both ends, is cemented into the bottom of G, and over it is placed a larger one closed at the top like a bell glass. The smaller tube thus forms the long leg of a syphon, and the larger tube acts as the short leg. The water, having risen to the level of the top of the inner tube, drops over into a little copper tilt, t, in the globe, S, beneath the reservoir. This tilt is divided into two equal partitions, and placed upon an axis not exactly balanced, but so that one end or the other pre- ponderates. The water drops into the end of the tilt which happens to be uppermost, and when quite full it falls over, throwing the water into the globe, S, from which it flows away by the waste pipe. In this way an imperfect vacuum is produced in the globe, quite sufficient to produce a draught in the 45, COBNHILL, E.G., AND 122, BEGENT STREET, W., LONDON. 109 small tube of the syphon, or the long leg ; and the whole contents of the reser- voir, 6r, immediately run off, and the spiral springs 6 &, elevate the reservoir to its original position. To produce this action, a quarter of an inch of rain must have fallen. The registration is easily understood. A spring lever, z, carrying a pencil, is attached by a cord, c, to S. This spring always keeps the cord tight, so that as the apparatus descends during the fall of rain, the spring advances the pencil more and more from the zero of the scale upon the paper beneath, until a quarter of an inch has fallen, when the pencil is drawn back to zero by the ascent of the reservoir. The registration trace for twenty-four hours is readily understood. The direction is recorded on the centre part ; the pressure on one side, and the rain on the other. Lines parallel to the length of the paper show no rain, steady wind, and constant pressure. On the rain-trace, a line parallel to the width of the paper, shows that the pencil had been drawn back to zero, a quarter of an inch of rain having fallen. The hour lines are in the direction of the width of the paper. Price, for Osier's Self-registering Anemometer and Rain Gauge, fig. 117, from 84 to 150. 150. Beckley's Anemometer. Mr. R. Beckley, of the Kew Observatory, has devised a self-registering anemometer, which consists of three principal parts : Robinson's cups for the determination of velocity ; a double fan, or windmill governor, for obtaining the direction ; and a clock to move a cylinder, around which registration paper is wrapped. The paper records the time, velocity, and direction of the wind for twenty-four hours, when it must be replaced. It has a cast-iron tubular support, or pedestal, to carry the external parts the cups and the fan, which must be erected upon the roof of the building upon which it is desired to mount the instrument. The fans keep their axis at right angles to the wind ; and with any change of direction they move, carrying with them an outer brass tube, which rests upon friction balls on the top of the pedestal, and is attached to a tubular shaft passing through the interior of the pedestal, and terminating with a mitre wheel. The mitre wheel, working with other cogged wheels, communicates the motion of the direction shaft to a cylinder carrying a pencil, to record the direction. The shaft carrying the cups is supported upon friction balls, placed in a groove formed on the top of the direction shaft, and passing through the interior of that shaft, comes out below the mitre wheel, where it is terminated in an endless screw, or worm. 110 NEGRETTI AND ZAMBRA, HOLBORN YIADUCT, E.C., Beckley's Recording Anemometer. Upon the wind moving the cups motion is given to the innermost shaft, thence to the wormwheel, whence motion is given to a pencil which registers the velocity. 45, COKNHILL, E.G., AND 122, KEGENT STREET, W., LONDON. Ill De La Rue's metallic paper is used in registration, it having the property of receiving a trace from a brass pencil; The pencils can, therefore, be made in the most convenient form. Mr. Beckley forms each pencil of a strip of brass wrapped round a cylinder, making a very thin threaded screw, so that the contact of the pencil cylinder and the clock cylinder is a mere point of the metallic thread. The pencil cylinders are placed side by side upon the drum turned by the clock, and require no spring or other appliance to keep them to their work, but always make contact with the registration paper by their own gravity. They therefore require no attention, and being as long as the trace which they make they will last a considerable time. The velocity pencil has only one turn on the cylinder, and its pitch is equal to a scale of fifty miles upon the paper. The direction pencil has likewise one turn on its cylinder, its pitch being equal to a scale of the cardinal points of the compass upon the paper. The Clock gives a uniform motion of half an inch per hour to the Drum upon which the paper is secured. In the Report of the British Association for 1858, Mr. Beckley has given a detailed description of his Anemometer, with drawings of all the parts. Our engravings (figs. 118 and 118) show the general arrangement and details. The price of Beckley 's Anemometer depends so much upon the fittings and the amount of work required to suit it to the building upon which it is to be fixed that Negretti and Zambra can only quote 80 to 120 as the probable cost of the instrument. 151. Negretti and Zambra' s Anemometer as erected on their Holborn Viaduct Establishment, shewing Direction and Pressure on Dials in the base of the building. Cost according to position in which it is to be fixed. Special Estimates given for numbers. 152. Our List of Registering Anemometers will hardly be deemed complete without the mention of some exceedingly ingenious contrivances for obtaining records of the movements of the wind by the use of a Galvanic current so arranged that any alteration in the direction or force of the wind is instantly carried down to a dial or revolving drum or other me- chanical contrivance for receiving the indications. A very elaborate description will be found in Kaemtz's Meteorology, of Professor Wheatstone's Electro-Magnetic Meteorological Register, and in several foreign meteorological publications will also be found details of many similar applications of the electric current. Louis J. Crossley, Esq., of Halifax, has devoted a very large amount of time and attention in perfecting a recording modification of Kobinson's Anemometer, in connection with a galvanic receiving and transmitting apparatus with considerable success ; but owing to the difficulty of maintaining the connections and contact breaks in perfect working order, and the consequent probability of defects in the registration, the Electro-Magneto Anemometers are but rarely used. N. and Z. have recently fitted up several different arrangements of Electrical Anemometers to special order and drawings, these under careful supervision are now performing satisfactorily. 112 NEGRETTI AND ZAMBRA, HOLBOEN VIADUCT, E.G., APPARATUS FOR TESTING THE ELECTRIC CONDITION OF THE ATMOSPHERE, 153. Ozone*. During the action of a powerful electric machine, and in the decomposition of water by the voltaic battery, a peculiar odour is perceptible, which is considered to arise from the generation of a substance to which the term Ozone has been given, on account of its having been first detected by smell, which for a, long time after its discovery was its only known characteristic. A similar odour is evolved by the influence of phosphorous on moist air, and in other cases of slow combustion. It is also traceable, by the smell, in air, where a. flash of lightning has passed immediately before. Ozone according to Faraday is oxygen is an allotropic condition, and from the observations of Mr. Glaisher is to be found almost always present in the atmosphere ; the quantity depending on the elevation above the surface of the earth, and the prevalence of particular winds, being more abundant during southerly than during northerly winds, and at a high elevation than at the surface of the earth. It is more abundant at the sea-side than inland, and is almost absent in thickly-populated towns. This may seem, remarks Admiral FitzRoy, in The Weather Book, to point to some connection between Ozone and Chlorine gas, which is present in and over sea water, and is no doubt brought inland by any wind blowing from the. sea. Ozone plays an important part in the purification of the atmosphere, and its continued presence in a locality indicates a pure and healthy climate. More and careful observations are however required before its true functions can be determined. M. Howzeau states : That the amount of Ozone in the air is variable, the maximum being about one volume of Ozone in 700,000 of air. Ozone possesses the property of bleaching blue litmus paper without previously reddening it, and it is found present most in Spring, less in Summer, diminishing in quantity in Autumn, and very little in Winter. Generally it may be detected during Wet and Stormy weather, and largely augmented in quantity after heavy Snow Storms. Dr. B. W. Richardson, F.R.S., in a Lecture on Yital Air, delivered at the Society of Arts, states, as an undoubted fact, that he found that oxygen which had been rendered prejudicial to animal life from repeated breathing was restored by means of an electric discharge to its original exhilarating state, and was again capable of supporting animal life. So that there is, possibly, a very close relation between the electrical condition of the atmosphere and the amount of ozone present, as indicated by the Ozonometer. The ozone is usually * Discovered by Schonbein in 1848. 45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 113 in excess during disturbed electrical weather, and in a deficiency during calm and settled periods. We cannot lay too great a stress on the fact that where different kinds of ozone tests are made use of by different observers, no uniformity in results can be attained. Having this in view, we have prepared our ozone tests (see No. 157) on a formula, by which we can obtain uniformity in the indication and results that can be compared no matter how far the stations may be removed from one another. It is important to note this, as we often receive complaint of the failure of other Ozone Test Papers. It is recom- mended to take observations every twelve hours where practicable, as there is a marked difference in the amount of ozone registered in the day and night. APPARATUS FOR PRODUCING OZONE. A simple method of producing Ozone is passing sparks from an Electrical Machine through a confined portion of Air in a glass vessel. 154. Ozone Tube. A convenient form of apparatus for the production of Ozone. It consists of a glass tube about j of an inch diameter, and five or six inches in length, coated outside with tinfoil and enclosed in an outer tube, also covered outside with tinfoil. These tubes are so arranged that the intervening space between the tubes shall be as small as possible; the coating of the inner tube being put into connection with the terminal of the secondary coil of an inductorium, and the outer coating connected with the other terminal of the same coil. The apparatus forms, in fact, a kind of Leyden Jar, and air or oxygen passing between the tubes when the coil is in action becomes very strongly ozonised. The air to be operated on is either to be drawn or forced through the apparatus by the aid and use of an Aspirator or Gasometer. Price for the above, conveniently mounted . . .150 155. Ozone may also be made by passing a current of dry air or oxygen from a gasometer through a narrow glass tube, bent for convenience like the letter U, about three feet in length, and containing a platinum wire two feet in length, inserted into the interior of the tube, and one end of which communi- cated with the outside through the wall of the tube. Round the whole external surface of this U-shaped tube a spiral of copper wire is to be coiled, and an induction current (from a coil giving half-inch sparks), is to be passed between the external copper to the internal platinum wire, so as to have the platinum wire as the negative pole in the interior of the glass tube. After a stream of gas is ozonised by the transmission of the induction-current, it is to be washed by passing it through a bulb tube containing caustic potash, when air is employed ; or water, when pure oxygen is used ; in order to eliminate any traces of nitrous and nitric acids that may have been formed. By means of a gasometer the volume of gas passing through the tube may be exactly ascertained. i NEGRETTI AND ZAMBRA, HOLBORN YJADUCT, E.G., The apparatus described afc No. 155 was used by Mr. Dewar and Dr. McKendrick in carrying out some experimental research on the Physiological Action of Ozone, the results being communicated by them to the Royal Society of Edinburgh. In their paper the authors point out that little was known regarding the action of Ozone, except its peculiar smell and the irritating effect it had on the mucous membrane of the respiratory tract. Schonbein had shown that a mouse died in five minutes in an atmosphere highly charged with Ozone ; and it was this distinguished investigator who asserted that there was a relation between the quantity of Ozone in the air and the prevalence of epidemic diseases. The result of Messrs. Dewar and McKendrick's experiment was, that a full grown, healthy mouse lived nineteen minutes after the introduction of ozone into the confining vessel, and that in ozonised oxygen, instead of dying at the end of fifteen or twenty minutes, (as happened to mice in ozonised air), they lived for forty or sixty minutes. In concluding the paper the authors stated that it would be premature, at this stage of the inquiry (which opened up many points of interest in the physiology of respiration), to generalise between physiological action and the physical and chemical properties of ozone. Series of researches are still being prosecuted () on the action of smaller percentages of ozone ; (&) on the action of ozone on noxious gases and effluvia ; and (c) on any therapeutical or hygienic influences it may have on the origin and treatment of zymotic diseases. 156. Dr. Moffatt's Ozonometer consists of strips of paper prepared with Iodide of Potassium and Starch ; these papers are suspended in a box so as to be exposed to the free access of air, protected from the direct rays of the sun and also from rain. The paper when affected by Ozone is tinged with various shades of brown, the intensity of which is measured by a scale of ten gradations furnished with the test papers. 157. Negretti and Zambra's Ozonometer. These tests are now prepared on a nevv formula, by which uniformity in the indications is secured together with great sensitiveness and keeping qualities. In Tin Boxes sufficient for 12 months' observations, with Colour scale and full instructions for use Price, 8s. 6d. 158. Schonbein's Ozone Tests Price, 6s. 6d. 159. Ozone Box, constructed of painted deal on the plan recommended by Dr. Moffatt. Price, 110 160. Sir James Clarke's Ozone Case (fig. 119), consists of two cylinders of very fine wire gauze, one fitting into the other ; the wire gauze being of such a fineness as to permit the free ingress of air, at the same time that it shuts out all light that would act injuriously on the test paper, which is suspended by a clip or hook attached to the upper part of the inner cylinder. Price, 18 Ditto in Copper 150 161. Lowe's Ozone Case, Spiral form, japanned zinc. Price, 18 6 45, COEJfHILL, E.G., AND 122, REGENT STREET, W., LONDON, 115 FIG. 119. FIG. 120. 162. Atmospheric Electricity. The general electrical condition of the atmosphere is positive in relation to the surface of the earth and ocean, becoming more and more positive as the altitude increases. When the sky is overcast, and the clouds are moving in different directions, it is subject to great and sudden variations, changing rapidly from positive to negative, and the reverse. During fog, rain, hail, sleet, snow, and thunderstorm, the electrical state of the air undergoes many variations. The intensity of the electricity increases with hot weather following a series of wet days, or of wet weather coming after a continuance of dry days. The atmospheric electricity, in fact, seems to depend for its intensity and kind upon the direction and character of the prevailing wind, under ordinary circumstances. It has an annual and a diurnal variation. There is a greater diurnal change of tension in winter than in summer. By comparing observations from month to month, a gradual increase of tension is perceived from July to February, and a decrease from February to July. The intensity seems to vary with the temperature. The diurnal variation exhibits two periods of greatest and two of least intensity. In summer, the maxima occur about 10 a.m. and 10 p.m. ; the minima about 2 a.m. and noon. In winter, the maxima take place near 10 a.m. and 8 p.m. ; the minima near 4 a.m. and 4 p.m. i2 110 NEGBETTI AND ZAMHRA, HOLBORN YIADUCT, E.C., FIG. 121. FIG. 122. FIG. 123. FIG. 124. 163. Singer's Electrometer for Atmospherical Electricity. (fig. 120). This instrument is arranged with a brass rod about two feet in length and a clip for the reception of a lighted cigar fusee ; the electricity is collected by the flame, and cond acted down the rod to a pair of gold leaves, which separate according to the amount ; the kind is determined by the effect of either a stick of excited sealing-wax, or a glass rod, supplied with the instrument A glass rod when rubbed produces positive electricity ; a stick of sealing- wax similarly treated produces negative ; if, therefore, when the leaves are sepa- rate, we apply an excited glass rod, and they separate still further, the electricity is positive ; if they approach it is negative ; on the contrary, if we use a stick of sealing-wax, the leaves will separate if they are charged with negative electricity, and converge if positively charged, from the fact that all bodies similarly electrified repel each other, whilst those oppositely electrified attract each other. 110 A book containing strips of gold leaf, to replace the gold leaves when torn or broken in use. Price 016 To mount fresh gold leaves, unscrew and withdraw the brass plate to which is attached the rod supporting the leaves : then moisten with the breath the flat piece of brass, and press it gently down on one strip of gold, whilst the book is only partly opened ; the second leaf is attached in the same manner. 164. Bohnenberger's Electroscope (fig. 121), with Zamboni's Dry Piles, arranged with adjustments for regulating the distance between the gold leaf and the polar plates, an exceedingly delicate instrument for indicating the presence and quality of electrical currents. It can be mounted with a metallic conductor, and used with great advan- tage for observing atmospheric electricity. The principal parts of the instrument, as improved by Becquerel, are the following:^ I?, fig. 96, is a small 45, CORNHILL, EC, AND 122, BEGEtfT STREET, W., LONDON. 117 Zamboni's dry galvanic pile of 800 pairs, about a quarter of inch, in diameter ; and when the plates are pressed together, 2 \ inches in length. The bent wires above the pile terminate in two plates, P and If, which are the poles of the pile. These plates are parallel and opposite to each other. Their opposite sides are slightly convex, and gilded ; between is suspended a fine gold leaf, ~D G, which is attached to the metal conductor, C D. If the leaf hang exactly between the two plates, it is equally attracted by each, and will be in a state of repose. The apparatus is protected by a glass shade, having an opening at the top through which the metal wire, C D, passes, insulated by being con- tained in a glass tube, which is cemented to the glass shade by means of shellac. A metal plate is attached to the wire rod in connection with the gold leaf to convey to it the electricity to be tested. The electricity to be tested will be conveyed by the metal wire to the gold leaf, and the latter will immediately move towards the plate which has the opposite polarity. This electroscope is, beyond doubt, one of the most delicate ever constructed, and is well adapted to show small quantities of positive and negative electricity. Price, 880 165. Volta's Straw Electrometer, with graduated Arc, for estimating the amount of electric force by degrees of divergence. Price, 220 166. Cavallo's Pith. Ball Electroscope, (fig. 122) with graduated Arc for estimating the amount of electric force .... Price, t 10 167. Ditto ditto with Stopcock, fig. 123 . .220 168. Peltier's Tension Electrometer,* (fig. 124) according to Mr. Latimer Clark, was in all its essential parts first described and illustrated by Dr. Thomas Milner in the year 1 733. The instrument described as the inven- tion of Peltier in the Report of the British Association, 1849, and termed the Induction Electrometer, is constructed as follows : It consists of a light metal ball of about 4J inches diameter mounted on a brass rod, terminating in a flattened oval or heart-shaped aperture. In the centre of this aperture is placed a fine steel point on which is suspended a light copper or aluminium wire needle, with a small magnetic needle mounted on it at right angles. Two light metal rods or arms are extended from opposite sides of the support of the ball of the same length as the copper needle. Below these rods is a graduated circle, for estimating the value of the deflection of the needle in degrees. The support of the ball and centre of the needle is very carefully mounted and insulated on ebonite, and the whole mounted on a mahogany base with three adjusting screws. A cylindrical glass cover is placed over the graduated circle and indicating needle to protect them from currents of air, dust, &c. In use this electrometer is very carefully placed in such a position that the magnetic needle shall cause the light copper wire index needle to lie parallel * Peltier's Electrometer as used by Professor Palmier! at the Observatory on Mount Vesuvius. 118 NEGRETTI AND ZAMBEA, HOLBOEN VIADUCT, E.G., with and almost touching the two brass arms, when, if the apparatus lias been properly adjusted, if any cloud or portion of air in its vicinity be in an electrical condition it will act by induction upon the metal ball, and the needle will be deflected according to the amount and tension of the electricity. The quality of the electricity, if positive or negative, may be ascertained by the use of a rod of glass or shellac as described in directions for using the gold leaf instrument. (No. 163) In atmospheric observations the instrument may either be charged with free electricity and the indications of this needle noted at certain intervals, or it may be brought to the same degree of tension as the earth, and the inductive effects of the atmosphere upon it observed. Owing to its greater convenience the former method is now generally adopted, but the variations of the needle under atmospheric influences are far from being understood or reduced to a system. In use the Induction Electrometer is placed upon a stand about six feet from the ground, and to bring it into equilibrium of tension with the earth, touch the base of the stem with a conducting wire. When the instrument is removed from the inductive influence it indicates the presence of free electricity by the deflection of the needle. A regular and uninterrupted series of atmospheric observations with the Peltier instrument were made by M. Quetelet at the Royal Observatory at Brussels from August, 1844, till December, 1848. A strong inductive influence was generally noticed at the approach or cessation of rain. The maximum of atmospheric electricity was indicated in January, the tension of the atmospheric charge progressively diminishing until June, when it attained its minimum. The difference of the tension in these two months was in the proportion of 13 to 1. The results obtained by Mr. R. Birt at Kew are closely in accordance with those of M. Quetelet. Peltier's instrument is now constructed with a smaller ball, and without the metal shade as shown in our engraving, and the whole apparatus carefully insulated with ebonite (vulcanite), in place of shellac and resin. Price, 550 169. Thomson's Quadrant Electrometer complete with Lamp and Scales, including directions for use, in Mahogany Case, with Lock and Key. 36 170. Professor Sir W. Thomson's Portable Atmospheric Electrometer (attracted disc), fully described in Negretti and Zambra's Treatise on Meteorological Instruments, paragraph 135, pp. 130 and 131. Price with Electrophorous fitted in Mahogany Box 12 171. We have still to note the want of a portable and simple, but at the same time, accurate instrument to denote the electrical condition of the atmosphere. Many forms of Electrometers lately devised are but of little use to ordinary observers from their complex construction. 45, COENHILL, E.G., AND 122, EEGENT STEEET, W., LONDON. 119 172. Collection of Electricity. "A simple rough method of doing this is to shoot a metallic arrow upwards into the air, the arrow being tied to one end of a conducting string, the lower end of which carries a ring which rests upou the electroscope. The arrow being shot upwards, the electroscope will be found to be electrified, as it mounts ; and when the ring leaves the plate, the instrument will indicate the state of electrification of the air at that point where the arrow is at the time. "This manner of observing is simplified by substituting a long conductor reaching upwards; a gilded fishing rod may be employed, its lower extremity being insulated. " The usual method employed, however, is Volta's, in which the electricity is collected by means of a flame, burning at a height, either in a lantern hung to mast, and connected to the electroscope by a wire, or, by a slow burning match attached to the top of a long metal rod. " The electricity of the air in the neighbourhood of the flame, by its induc- tive action upon the conductor, causes electricity of the opposite nature to accumulate at the upper extremity, where it is constantly carried off by the convection currents in the flame, leaving the conductor charged with electricity of the same kind and potential as the air."* 173. " The princple of Volta's method has been made use of by Sir W. Thomson in his Water-dropping Collector, now employed in observatories, and found to be extremely useful for the observation of atmospheric electricity. A copper can is placed on an insulating support, which may be of ebonite, having the surface thinly coated with paraffin ; or of glass surrounded with pumice stone soaked in sulphuric acid. From the can a small pipe projects a consider- able distance into the air, and terminates in a fine orifice. The can being filled with water, and the tap which opens into the jet pipe turned on, a small stream of water is allowed to flow out, care being taken that it is so small that it shall break into drops immediately after leaving the nozzle of the tube. In half a minute from the starting of the stream the can will be found to be electrified to the same potential as the air at the point of the tube. This Collector cannot be employed during the time of frost, unless means are adopted to prevent the freezing of the water in the jet pipe. When obser- vations are to be made with a portable instrument, a slow burning match should be used. Sir William Thomson recommends for this purpose blotting paper, steeped in a solution of nitrate of lead, dried, and rolled into matches. As to the position of the Collector, since electrical density is greater on projecting surfaces, and less on hollow surfaces than on planes, the Collector should not be near trees or houses, nor within a closed space."* The above Apparatus and Collecting Match made to order. * Robert H. Scott, Esq., Meteorological Office. 120 NEGRETTI AND ZAMBRA, HOLBOEN VIADUCT, E.G., 174. Tide Gauge, Self-registering, Wegretti and Zambra's Im- proved Newman's (fig. 125), for recording the rise and fall of the tide, by a lined traced with a pencil on a ruled paper, wound on a cylinder moved round by a clock once in twenty-four hours. The paper showing the rise and fall in feet and inches, and also the time in hours. An exceedingly valuable.instrument for places where the phenomena of tides, and the construction of accurate tide tables are of the utmost importance. Such observations should also be accom- panied with the registration of atmospheric phenomena. The tide-gauge, shown in the illustration (fig. 125) consists of a cylinder, A, which is made to revolve once in twenty-four hours by the action of the clock B. A chain, to which is attached the float, D, passes over the wheel, (7, and on the axis of this wheel, (in about the middle of it), is a small toothed wheel, placed so as to be in contact with a large toothed wheel carrying a grooved pulley, E, over which passes a small chain. This chain, passing along the upper surface of the cylinder, A, and round a second pulley, F, at its further end, is acted on by a spring so as to be kept in a constant state of tension. In the middle of this chain a small tube is fixed for carrying a pencil, which, being gently pressed down by means of a small weight on the top of it, marks on the paper placed round the cylinder the progress of the rise or fall of the tide as the cylinder revolves, and as it is drawn by the chain forward or backward by the rise or fall of the float. The paper is prepared with lines equi-distant from each other, to correspond with the hours of the clock, A, crossed by others showing the number of feet of rise and fall. The cylinder while in action revolves from left to right to a spectator facing the clock, and the pencil is carried horizontally along the top of this cylinder ; the large wheel, G, is caused to revolve by the rise and fall of the float, which turns the wheel with the small pulley, E, attached to it. If the tide is falling, the small chain is wound round the cylinder, E, and the pencil is drawn towards the large wheel ; brst if the tide is rising, the small chain is wound on the cylinder, F, by means of the spring contained in it. Thus, by means of the rise and fall of the tide, a lateral progress is given to the pencil, while the cylinder is made to revolve on its axis by the clock, so that a line is traced on the paper showing the exact state of the tide continuously, without further attention than is necessary to change the paper once every day, and to keep the pencil carefully pointed ; or a metallic pencil may be used. As indi- cated, it is self-recording, requiring very little attention a few minutes every day being sufficient. These gauges are now in action in several parts of the world, faithfully recording the rise and fall of the tides. Price, fig. 125, N. and Z's. Improved arrangement, from 50 NOTE. The price for the Ruled Papers or Charts used with this Apparatus and No. 175, along with Charts for other Recording Instruments, will be found on page 132. FIG. 125. NEGRETTI AND ZAMBRA'S IMPROVED NEWMAN'S SELF-RECORDING TIDE GAUGE. 122 FEGRETTI AND ZAMBRA, HOLBOKN VIADUCT, E.C., A. Dial of clock. B. Float-wheel. C. Guide for recording pencil. D. Recording pencil. E. Hourly marker on datum lines. F. Datum lines and registering pencil. G. Main Drum driven by clock. H. Eeel of paper. I. Haul-off drum. J. Pendulum of clock. K. Driving weight of clock. L. Driving weight of haul-off drum. M. Haul- off drum winder. K". Platinum wire to float. FIG. 126. SIR WM. THOMSON'S TIDE-G-UAGB. 175. The instrument consists of an astronomical clock, float- wheel and gear work for reducing the scale, and three drums, the whole fitted on a suitable plate and supporting standards, and requiring no further fixing. The clock is fitted with a six- spur gravity escapement and compensated pendulum, and serves to show the time and to drive the centre or main drum of the instru- ment. The float wheel is provided with a right-angled groove in which the platinum wire of the float coils itself during the rising tide. The right-hand drum receives a reel of paper, and the paper is fitted to the instrument without further fixing. The haul-off drum receives the paper records after it has passed round the main drum. The paper may be left to accumulate almost without limit on the haul-off drum, or can be removed at any time. The datum line on the record paper is traced by a fixed pencil, which can be adjusted to any level. Any number of horizontal lines can be ruled in this manner if desired. 45, COENHILL, E.G., AND 122, REGENT STREET, W., LONDON. 123 Immediately at the side of the datum line registering pencil, is a pencil actuated by the clock, which causes it to trace a short vertical line at each hour, through the datum lines, the mark for noon and midnight being some- what different. In this case the pencil is arrested for two minutes when in marking it has reached the level of the datum line, when it is allowed to complete the marking. The distinction is introduced in order to facilitate the subsequent noting of the times and dates upon the record. The pencil tide recorder is made to counterbalance the float. wire when the scale is not too greatly reduced, in which case the weight of the float- wire is partially relieved by a counterpoise weight acting on the axis of the float-wheel. The system of making the recording pencil balance the float- wire is a great advantage over the system generally employed, and greater accuracy of recording is secured. The employment of a continuous roll of paper obviates the necessity of continually applying fresh paper to the recording drum, and the tide-gauge can thus be left untended, except for the purpose of winding the clock, for an indefinite period. The system also of ruling the paper by fixed pencils and marking the hourly times by the clock constitutes a marked improvement, no error can thus occur from the wrong setting of the paper. Prices. The Tide-guage with three barrels and continuous paper complete, best finish 95 Ditto with single barrel and extra finish . . . .fig. 126. 80 Ditto ditto to be used with previously divided paper . 54 Larger engravings of some improvements in Thomson's Tide Gauge sent upon application. 170. Negretti and Zambra's Portable Set of Meteorological Instruments. A small, but at the same time really useful and reliable set of Standard Meteorological Instruments has long been inquired for by observers on foreign stations, and others who are frequently travelling to different parts of the world. To meet this demand, Messrs. Negretti and Zambra have arranged sets of Meteorological Instruments to pack up into a very small space. The set contains ISTegretti and Zambra's Patent Maximum and Minimum Registering Thermometers, Wet and Dry Bulb Hygrometer, Aneroid Barometer for Altitude measurements, Negretti and Zambra's Improved Registering Maximum Thermometer with high range of scale, for Hot Springs, Solar Radiation Thermometer, Terrestrial Radiation ditto, Improved Boiling Point Apparatus, Rain Gauge and Graduated Measure, a Clinometer, Magnetic Compass, and Tape Measure. The whole arranged in a strong case; with lock and key. Price 18 18 These sets can be varied, or other Instruments added, to meet the wishes and requirements of purchasers. See also pages 106 and 107. Further details of the construction and use of Meteorological Instruments mil be found in Negretti and Zambra's TREATISE, with very many valuable and useful Tables of corrections, fyc., fyc. Seepage 133. 124 NEGRETTI AND ZAMBRA, HOLBORN VIADTJCT, E.G., ESTIMATES FOR SETS OF METEOROLOGICAL APPARATUS. 177. The Meteorological Congress of Vienna, recognising three classes of Observing Stations, we subjoin estimates for Sets of Meteorological Instruments suited to their requirements. No. 1. For an Observatory or Station of the First Order. In which independent meteorological observations are conducted, of the greatest precision, either by hourly readings or with the use of Self -Recording Apparatus. One Large Observatory Standard Barometer. One Independent Standard Thermometer. One Negretti and Zambra's Patent Standard Maximum Registering Thermometer. One Negretti and Zambra's Patent Standard Maximum Thermometer, Exposed Black Bulb. One Ditto Ditto Bright Bulb. One Negretti and Zambra's Improved Patent Maximum Thermometer, in Vacuum, with Test Gauge, No. 37. With Stand for ditto. One Negretti and Zambra's Standard Minimum Thermometer. One Ditto Ditto Ditto Mercurial. One Ditto Ditto Standard Terrestrial Radiation Thermometer. One Standard Wet and Dry Bulb Hygrometer. One Stevenson's Thermometer and Hygrometer Screen. One Glaisher's Rain Gauge, the New Pattern, complete, Copper. Two Extra Graduated Measures for above. A Series of Thermometers for Earth Temperatures at varying depths. One Negretti and Zambra's Maximum Thermometer, for Earth or Springs. One Gold Leaf Electrometer. One Anemometer, with two recording Dials. Recording Mercurial Barometer. Recording Thermograph. Recording Hygrometer. Recording Anemometer and Rain Gauge. Sunshine Recorder. Cost for the whole of above Kew verified, 330 to 450. In first class Observatories it is advisable to have duplicate instruments, where there is any liability of fracture, to avoid breaking off the continuity of the recorded observations. The No. 1 Set of Meteorological Apparatus can be much extended if it be desired, to make comparative or experimental observations. No. 2. Estimate for a Meteorological Observatory of the Second Order. One Standard Barometer. One Negretti and Zambra's Patent Standard Maximum Thermometer. One Ditto Ditto Standard Minimum Thermometer. One Solar Radiation Thermometer in Vacuo, with Negretti and Zambra's Improved Test Gauge. 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 125 One Solar Eadiation Thermometer, with Exposed Bulb. One Terrestrial Radiation Thermometer. One Glaisher's Eain Gauge, Copper, complete. One Anemometer, with two dials. One Wet and Dry Bulb Hygrometer. One Stevenson's Thermometer md Hygrometer Stand. Cost for the above Set of Apparatus, 22 to 25. No 2 Set of Apparatus is strongly recommended to private observers where complete and regular observations are taken of Barometric Pressure, Temperature, Humidity, Rain, Wind, and Electrical phenomena. The series can be reduced to form a Third Class set at 12 12s., where only a few of the more important meteorological observations are taken, or other instruments can be added to meet the requirements of the observer. It will be as well to note here that all observations should be made punctually at fixed hours. The Meteorological Office recommend that, at Observing Stations of the second order, observations be made at least twice a day, at homonymous * hours, for which 9 a.m. and 9 p.m. (local time), have been most generally approved of. In unsettled weather occasional observations should be made of any special meteorological facts that may occur. VERIFICATION OF STANDARD METEOROLOGICAL INSTRUMENTS. 178. The Kew Committee of the Royal Society undertaking the testing and verification of Meteorological Instruments by their Standards, Negretti and Zambra subjoin a list of the charges. At the same time, Negretti and Zambra would observe that, having absolute Standard Instruments of their own manufacture which have been compared both with Greenwich and Kew Observatory Standards, they are prepared to compare and give certificates with their own instruments free of charge, The Kew Committee wish it to be noted that they do not undertake the verification of inferior instruments, such as Barometers mounted on Wood Frames, and Thermometers not graduated on the Stem, and also that the Superintendent may at his discretion decline to receive instruments he may consider unfit for Scientific observation. Each. Standard Barometers with attached Thermometer 10s. 6d. Marine Barometers in Metal Mountings 15s. Od. Aneroid Barometers for Altitude Measurements compensated . . 15s. Od. Thermometers 2s. 6d. to 5s. Od. Eain Gauges 2s. 6d. * The term " homonymous " signifies hours of the same name, as 9 and 9, or 12 and 12. The most suitable hours are, to a certain extent, to be determined by the locality and climate. 126 NEQRETTI AND ZAMBRA, HOLBOJIN TIADUCT, E.G., N. & Z's Maximum Registering Thermometer. & Z's. Minimum Registering Thermometer. N. & Z's. Glashier's Standard Rain Gauge. FIG. 127. 179. NEGRETTI AND ZAMBRA'S FIVE GUINEA SET OF METEOROLOGICAL INSTRUMENTS consists of a Mercurial Barometer with attached Thermometer having Fahrenheit and Centigrade Scales, Registering Maximum Thermometer, Registering Minimum Thermometer, Rain Gauge and Graduated Measure, and a Wet and Dry Bulb Hygrometer, fig. 127. The whole of these instruments are very carefully manufactured and tested to ensure sufficient accuracy for ordinary observers at a moderate price. One important feature in this set is that the various instruments will travel securely, as, although they are not strictly a standard set, they have all Negretti and Zambra's improvements and Patents adapted to them, and are compared and verified by Negretti and Zambra, and, if desired, Certificates given. This set of meteorological instruments can be modified, and extended, to meet the wishes of our customers. Descriptive particulars of the construction and use of these instruments will be found in the previous pages, or in Negretti and Zambra's Treatise on Meteorological Instruments. See page 133. 45, CORNHILL, E.G., AND 122, REQENT STREET, W., LONDON. 127 LIGHTNING CONDUCTOKS AND FITTINGS. 180. Lightning Conductors should be pointed at the top, and extend a few feet above the highest point of the building or mast. They are best made of Solid Copper Hods or Copper Bands of sufficient diameter and thickness to convey the discharge without melting. Wire Hope of Copper is now much used, owing to its convenient adaptability to uneven surfaces, but great care must be taken to have it of sufficient diameter to prevent fusion, and that both solid rods and wire rope should be perfectly continuous and unbroken throughout the entire length, and carried down some considerable distance into the earth, which should be moist, or better still, carried down a well some distance beneath the surface of the water, or the conductor should terminate in several branches on a large sheet of stout copper. In large towns these conductors are carried down and connected with the large water pipes. On no account should Lightning Conductors be connected with Gas pipes; it is exceedingly dangerous. Where a building is large, several conductors should be used, and all large and detached masses of metal in the fabric connected together and then united with capacious conductors leading directly from the highest points of the structure to the earth or sea. In applying such conductors to ships, each mast should have its own conductor, of sufficient size, permanently fixed, and connected with bands of stout copper passing through the sides of the ship under the deck beams, and with the large bolts leading through the keels and keelson to the water, including in the circuit all the principal masses of metal used in the construction of the vessel. It is of the utmost importance, that Lightning Conductors be periodically examined to see that they are in perfect condition, as any defects in continuity of the metal rod or wire may lead to serious results. Several instances of most destructive damage both to buildings and ships having lately occurred, arising from defective conductors, we cannot too strongly urge the attention to this caution. FIG. 128. NEGRETTI AND ZAMBRA, HOLBOEN YIADIJCT, E.G., FIG. 131. . Solid Copper Point Lightning Conductor with 3 3 Attractors, as fig. 129, Copper elevating tube 25 5 feet long, Couplings, Straining Bolt, Insu- lators, and Holdfasts, all complete with 50 feet Solid Copper Rope f inch diameter . . . 4 10 6 Ditto Ditto, with 75 feet Solid Copper Rope -| inch diameter . . . . . 5 15 Ditto Ditto, with 100 feet Solid Copper Rope inch diameter 700 Ditto Ditto, with 150 feet Solid Copper Rope inch diameter . . . . . . 9 12 Ditto Ditto, with 50 feet Solid Copper Rope | inch diameter . . . ... . .550 Ditto Ditto, with 75 feet Solid Copper Rope | inch diameter . . . . . . 6 16 Ditto Ditto, with 100 feet Solid Copper Rope \ inch diameter . . . .876 Ditto Ditto, with 150 feet Solid Copper Rope \ inch diameter . . . . 11 10 Ditto Ditto, with 100 feet Solid Copper Rope J- inch diameter . . . . 9 16 Ditto Ditto, with 150 feet Solid Copper Rope f inch diameter . . . . 13 17 6 Plain Point Solid Copper Bod Lightning Conductor, for Copper Rope T ^- inch diameter, no Insulators or Tightening Bolt (fig. 130) 150 Plain Spear Point Solid Copper Lightning Conductor with Coupling for Rope End and Copper Elevating Tube 4 feet long (fig. 130*) . . . . 1 12 FIG. 130* 45, COENHILL, B.C., AND 122, EEGENT STREET, W., LONDON. Solid Copper Lightning Conductor fitted with Point and three Attractors, as fig. 129, with 7 Holdfasts, 7 Insulators, and 1 Straining Bolt, complete ....... Ditto Ditto, with 11 Holdfasts and 11 Insulators . Ditto Ditto, with 15 Holdfasts 15 Insulators . Ditto Ditto, with 24 Holdfasts and 12 Insulators . 129 Each. s. 2 14 3 3 6 4 4 If the Points are wished tipped with Platinum, there will be an extra charge, according to the size and weight. Price variable. Galvanised Iron Holdfast, to build in, Ditto Ditto Ditto Ditto Ditto Ditto Straining Bolt No. 1, fig. 131, per doz. to Drive No. 4 Do. per doz. for passing along Slated Roof, No. 3 Do. per doz. extra strong, for supporting Bod or . No. 2 Do. per doz, Copper Elevating Rod, No. 6, fig. 130*, showing Holdfast and Glass Insulator, to steady the same ...... Straining Bolt, No. 7, fig. 130*, with Glass Insulator and Holdfast complete for til m ch diameter Rope 12s. 6d., 10s. 6d., 7s. 6d., per set. Tension Bolt, for tightening and straightening the wire, of a simple form 8s, 6d. Glass Insulators annealed with lock nibs . per doz. 10s. and Solid Copper Wire Rope, f inch diameter. Price per 100 feet . Ditto Ditto J inch diameter. Ditto Ditto I- inch diameter. Price per 100 feet Price per 100 feet 096 096 11 6 10 086 10 6 14 6 10 550 3 16 NOTE. The prices for Copper goods vary according to the market value of the metal. At a small increase of cost the Points can be strongly gilt. Estimates given for fitting up Lightning Conductors, either with Copper Wire Rope, Solid Copper Rod or Bands. 181 Lightning Conductors, The celebrated American philosopher, Franklin, in the year 1749, first discovered the means of averting the destructive and fatal effects of lightning by the use of pointed metallic rods attached to high and exposed buildings, his experiments having proved that the electric fluid will always follow the path of least resistance to the earth. In confirmation of the value of Lightning Conductors as a safeguard, we quote the following from Sir W. Snow Harris : " It appears from the records of the Navy, that the destructive effects of lightning on H.M. ships involved in former years an expenditure of not less than from 6,000 to 10,000 annually. In 200 cases only, 300 seamen were either killed or hurt, and above 100 large masts valued at the time at from 1,000 to 1,200 each entirely ruined. Between 1810 and 1815, 35 sail of the line, 35 frigates and smaller vessels were completely disabled. " Since the system of Lightning Conductors has been fully carried out in all H.M. Ships, it appears damage by lightning has almost vanished from the records of the Navy." FIG. 132. 130 NEGBETTI AND ZAMBRA, HOLBOEN YIADUCT, E.G. TERRESTRIAL MAGNETISM. FIG. 133. 134. Magnetograph or Self-Recording Magnetometer (fig. 133), recommended by the Meteorological Committee of the Royal Society and used at KQVV Observatory. This apparatus, invented and arranged by Mr. Beckley, records the variations continually occurring in the Earth's Magnetism by the aid of photography. Three drums or cylinders, to which are attached sheets of sensitised paper, are revolved by a clock movement (seen in the centre of the engraving), and receive the rays of light projected from small mirrors attached to each of the three magnets so arranged as to exhibit all the variations of Magnetic Force, Inclination, Direction, and Intensity. The lights used are Gas Burners or Paraffin Lamps. Our limited space will not permit our giving full details of the various mechanical contrivances made use of in this apparatus, which in many respects are somewhat similar to those employed in the Recordiag Barograph, Thermograph, and Hygrometer shown on pages 30 and 78. The Magnetograph is supplied by Negretti and Zambra to special order. Price 350 to 500 45, COKNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 131 135. Unifilar Magnetometer, Kew Pattern, Portable arrangement, packed in two boxes complete. Price, 70 136. Kew Pattern Dip Circle, or Inclinometer, of the most recently improved arrangement, complete, with Lloyd's Total Force Apparatus and Kew Verification. Price, 35 137. Seismograph, Professor Palmeri's recently improved arrangement for recording and measuring the various Volcanic and subterranean tremors and disturbances of the Earth. Price complete in Glass Cases, 150 138. Van Rysselberghe's Universal Meteorograph. For recording by the aid of Electricity the indications of Meteorological Instruments at regulated periods of time. These records are registered upon a metallic surface every 15 minutes, and from them any number of copies can be produced. Similar to N". & Z's. Recording Thermometers and Hygrometers, Nos. 74 and 103, the Meteorograph can be constructed to register indications of meteorologic apparatus in action at a great distance from the observing station. The simplest arrangement of this apparatus includes a Barometer, Hygrometer, Rain Gauge, and Anemometer, with Direction Vane. Complete with Galvanic Batteries and a supply of Sheets of Zinc, &c. Price, 240 This price will vary with the number of Instruments of which records are desired. 139. Solar Intensity Apparatus, Padre Secchi's, for measuring the comparative heat of the Sun's Rays. Price complete with three Thermometers, 440 140. Piche's Evaporimeter with graduated glass Tube. Price, 13 141. Pocket Spectroscope, for observing the Rain Band, fixed slit, in Leather Case. Price, 1 15 142. Ditto Ditto with adjustable slit and Leather Case. Price, 2 10 143. Direct Vision Rain Band Spectroscope, larger size, of very great dispersive power, in Leather case. Price, 550 For further description and prices of Electrical Galvanic, Magnetic and Electro-Magnetic Instruments and Apparatus , see special sections at end of this Catalogue. K2 132 NEGEETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., NEGRETTI AND ZAMBRA'S BAROMETER CHARTS. AND THERMOMETER "THE DAILY TELEGRAPH BAROMETER CHART. [FROM NEGRETTI AND ZAMBRA'S SELF-REGISTERING BAROMETER.] The method of keeping the Barometer and Thermometer Charts is well shown in our diagram, (fig. 134). This is an actual reprint from a Chart pub- lished in the Daily Telegraph newspaper, of the morning of May 21st, 1877. By a most ingenious arrange- ment of fixed and movabletypes invented by Negretti and Zambra, the rise and fall of the mercury in the Barometer tube (as indi- cated by Negretti and Zambra's Recording Barometer) is pub- blished every morning in the Daily Telegraph, the diagram exhibiting the indications of the Barometer for the previous four days and to within a few hours of going to press. Modifications of this method of publishing a daily Barometrical record have been carried out by the firm for several other daily papers, and in varying forms are now used by almost every daily and weekly newspaper. FIG. 134. The above chart represents the movement of the oarometer. corrected for sea-level and reduced to 32 F., during the last four days ending midnight, May 20-21. GENERAL REMARKS. A return of a north-easterly wind, accompanied by occasional showers of drizzling rain, caused the weather yesteiday to be very bleak and unseasonable* The barometer rose throughout the day, the reading at midnight being 80' 11. DOVER. Fine and cold ; wind S.W. ; sea rough j bar. steady. 144. CHARTS FOE KEEPING A RECORD OF THE VARIATIONS or THE BAROMETER AND THERMOMETER. Each sheet is ruled and figured for one month's observations ; twelve of these sheets are neatly mounted on a card, so that when one month's readings are ended the sheet can be removed by cutting round the edge with a sharp knife, and a fresh sheet will be exposed. These records form a most interesting and valuable reference for comparing present and past weather. Price of each pad of 12 sheets, for Barometer, 2s. 6d. Ditto ditto for Thermometer, 2s. 6d. Combined ditto for Barometer, Thermometer, Hygrometer, Eainfall, &c., 2s. 6d. These Pads of Charts can be forwarded by Book Post for Fourpence. Ruled Cliaris or Diagrams for the Recording Barometer, fig. 21, and Recording Aneroid Barometer, figs. 28 and 29 price, per hundred 150 Ditto Ditto, for Recording Anemometers, figs. 117. 118 and 118* 150 Ditto Ditto, Ditto, Tide Gauges, figs. 125 and 126 1 1 45, COBNHILL, E.C., AND 122, EEGENT STEEET, TV., LONDON. 133 METEOROLOGICAL PUBLICATIONS, ELEMENTARY METEOROLOGY. ROBT. H. SCOTT, Esq., M.A., F.R.S. Price 5s. A TREATISE ON METEOROLOGICAL INSTRUMENTS, Explanatory of their Scientific Principles, Method of Construction, and Practical Utility, by NEGEETTI AND ZAMBEA. Numerous Tables of Reference in connection with Meteorology. Illustrated with 100 Engravings. Price 5s. HYGRO METRICAL TABLES, Adapted to the use [of Negretti and Zambra's Wet and Dry Bulb Thermometer, by J. GLAISHEE. Esq., F.R.S. Price 2s. 6d. TABLES OF THE CORRECTIONS FOR TEMPERATURES, to reduce observations to the 32 Fahrenheit, for Barometers with Brass scales ex- tending to the top of the mercurial column. By J. GLAISHER, Esq., F.R.S. Price Is. 6d. TABLE OF THE DIURNAL RANGE OF THE BAROMETER. By JAMES GLAISHEE, Esq., F.R.S. New Edition. Price Is. 6d. TABLES FOR CALCULATION OF HEIGHTS from Observations on the Boiling Point of Water, arranged for use with Negretti and Zambra's Boiling Point or Hypsometric Apparatus. By the late Mr. WELCH, of the Kew Observatory. Price Is. BAROMETER MANUAL, OR HOW TO FORETELL WEATHER, compiled by Admiral FiTZ-RoY, F.R.S., &c., for the Board of Trade. Published by NEGEETTI AND ZAMBEA with permission Price 6d. TABLE SHOWING THE READINGS OF THE BAROMETER, Corres- ponding Numbers of Elevation in English Feet, and of Readings of Aneroid or Corrected Barometer in English Inches ; (the Mean of Atmos- pheric Temperatures being 50 Fahrenheit). Compiled by the late Astronomer Royal for NEGEETTI AND ZAMBEA. Price 6d. L. F. KJBMTZ'S COMPLETE COURSE OF METEOROLOGY. Translated by C. Y. WALKER, Esq. Price 12s. 6d. POCKET METEOROLOGICAL REGISTER AND NOTE BOOK. (Strachan's) with Diagrams for exhibiting the Fluctuations of the Baro- meter, Thermometer and Hygrometer. NEGEETTI AND ZAMBEA. Price 2s. 6d. SYMONS', G. J. British Rainfall (published annually since 1865). each 5s. Monthly Meteorological Magazine, Vols. I. to XIX. each 5s. SYMONS', G. J. Meteorological Register, with Instructions, for one year, 2s. for five years, 7s. 6d. SYMONS', G. J. Blank Diagrams for Barometer and Thermometer, for one year, Is. SYMONS', G. J. Blank Rainfall Register for one year, 3d. 134 NEGEETTI AND ZAMBEA, HOLBOEN YIADUCT, E.G. DIAL AND PEDIMENT BAROMETERS, THE ordinary household Barometers or Weather Glasses are constructed in two forms, viz., the Wheel or Dial Barometer, and the Pediment or Upright Barometer. The former reading by an extended circular scale, and the latter from the actual mercurial column. The Dial Barometer is mounted with the syphon form of tube as shown in our Diagram, the shorter -limb of the syphon being about six or eight inches long. This obviates the use of a cistern, for with sufficient mercury in the short tube, that in the longer one will be balanced at a varying height in accordance with the increased or diminished pressure of the atmosphere. This form of Barometer was first constructed by the celebrated philosopher Dr. Hook, in 1667 ; the principal advantage of the dial arrangement is that by it a small movement in the mercurial column is magnified and made very apparent, a tenth of an inch rise or fall being represented by the index moving over nearly one inch on the dial ; this enables the unscientifiVobserver to notice quickly if the Barometer be rising or falling and estimate the probability of fine or wet weather. On the top of the mercury in the short limb of the tube is suspended a glass float, by a silk cord which passes two or three times round a small brass wheel or pulley ; at the other end of this silk cord is placed a counterpoising glass weight, moving freely in a second tube placed at the side of the syphon for the purpose of steadying the weight. The axis of the pulley is carried through the wood frame of the Barometer to the front of the instrument, where the movement of the mercury is shown by a light index hand attached to it, traversing a divided dial. As the mercury in the Barometer tube rises, the silk cord descends, causing the index hand to move to the right ; on the contrary, as the mercury falls the index will be carried in the reverse direction to the left. The graduations on the dial represent the actual inches of a Standard Barometer Scale, extended as previously described, giving what is termed a very open scale. If the mercury rises half an inch in the long tube it will fall half an inch in the shorter one. Therefore, as the mercury rises half an inch in the one tube and falls half an inch in the other, the length of the barometrical column has increased one inch, but the movement has only been through half an inch this amount of movement transferred to the pulley causes the index hand to indicate an inch movement on the dial, say from twenty-nine to thirty inches. 45, COENHILL, B.C., AND 122, REGENT STREET, W., LONDON. 135 145. Our engraving (fig. 135) exhibits the general internal arrangement of the Dial Barometer. A B is the mercurial syphon tube, and at W is seen the glass weight or float attached to a silk cord. This weight floats upon the surface of the mercury rising or falling in the tube in accordance with the movement of the mercurial column; by the side of the syphon is a second guide tube, D, for the counter- poise weight C, at P is shown the pulley over which the silk cord passes giving movement to the index hand over the Dial as previously described. At the side of the diagram we show a wire plug, E, used for making these barometers portable for travelling or exportation. It is simply a stiff wire covered witb cotton throughout its whole length, and as will be seen in the drawing, it has sufficient cotton woand round the lower end to fit the mercurial tube tightly at two points, TO MAKE THE DIAL BAROMETER PORTABLE. 146. By inclining the Barometer the mercury is caused to fill the tube entirely, the float is then with- drawn from the mercurial tube W (carefully avoiding disturbing the silk cords, most of Negretti and Zambra's Barometers are now fitted with a brass clamp to secure the cords), and then the plug E is FIG. 135. forced slowly down the tube until the mercury is perfectly secured. The glass float being placed at the side of the syphon and secured with a little soft packing carefully placed round it and the glass tubes, the instrument is now made portable or secure for transit. We need hardly point out that the Dial Barometer must not be regarded as an instrument of precision, but simply as a weather indicator or household Barometer. Instructions for setting the Barometer in action will be sent with each instrument if it has been made portable. The absolute height of the Barometer, at any moment, does not always indicate present weather. The rise or fall of the mercurial column supplies the information of coming weather or change. A rapid rise or fall indicates changeable and unsettled weather. A falling Barometer and rising Thermometer, are commonly and quickly followed by rain. "The longer the time between the signs and the change they foretell, the longer will the altered weather last ; and the shorter between the warning and the change, the shorter the continuance of the changed weather." " A fall, with a low Thermometer, foretells Snow." When the Barometer falls with the wind S.E., it is generally followed by long continued Rains. A rapid fall of the Barometer is usually followed by much wind as well as Rain. For further hints How to foretell the Weather see N. and Z's. Barometer Manual, compiled for them by Admiral Fixz-ROY. Price, post free, Sixpence. 136 NEGEETTI AND ZAMBEA, HOLBOEX VIADUCT, E.G., DIAL BAROMETERS, OR WEATHER GLASSES. FIG. 159. FIG. 158. FIG. 159*. BAROMETERS being now mounted in so many varied styles, both plain and carved, the following are given as a few specimens of those most in demand. Large stocks of these instruments are always kept at all of ISTEGRETTi and ZAMBRA'S establishments of most of the patterns shown in the engravings. Barometers supplied to order of any style of Architecture, to correspond with the furniture of Libraries, Halls, &c, NOTE. The marginal Nos. from this page will as far as possible correspond with those of the woodcuts. 45, COENHILL, B.C., AND 122, EEGENT STRKET, W., LONDON. 137 147 148 149 150 151 152 153 154 155 156 FIG. 154. Each. s. d. 220 Each. s. d. 1 10 2 10 3 10 2 10 FIG. 153. FIG. 150. 8-inch Silvered Brass Dial Barometer, common, mounted in mahogany or rosewood frame, with or without mirror, hygrometer, and level 8 -inch ditto ditto, square bottom Ditto, ditto, superior finish, engraving, and large tube 10-inch Silvered Brass Dial Barometer, in common mahogany or rosewood frame, with or without mirror, hygrometer and level (fig. 150) 2 Ditto, Ditto, square bottom (fig. 151) 2 Ditto, Ditto, Extra best both as regards frame, dial, engraving and tube (figs. 151 or 154) . . . . 3 10 440 12-inch Dial Barometers of the same patterns, 15s. to 1 5s. extra. 8-inch Scroll Pattern Dial Barometer, best mounted mahogany, oak, walnut, or rosewood frames, silvered brass dial, with Thermometer (fig. 153) 10 and 12-inch Scroll Pattern Barometers, 20s. to 50s. extra. 8-inch Dial Barometer, with ornamental figures, letters, and 'divisions on PATENT ENAMELLED GLASS DIAL (fig. 154) , 8-inch Dial Barometer, rosewood frame inlaid with PEARL or METAL, with silvered brass dial .... 10-inch ditto, best rosewood frame inlaid with PEARL or METAL, the dial of silvered metal, with Thermometer, superior finish Nos. 155 & 156 fitted up to order (fig. 156) 12 and 14-inch Dial Barometers ditto, at proportionate prices. 330 440 550 880 12 12 138 NEGRETTI AND ZAMBEA, HOLBORN VIADUCT, E.G., FIG. 156. Fm. 157. FIG. 158*. Each. 157 d. 158 159 14-inch Dial Barometer, best rosewood frame inlaid with PEARL or METAL, the dial of silvered metal, and an eight-day Clock fitted in the frame, Thermometer, &c. (fig. 157) fitted up to order . . 25 8 and 10-inch Dial Barometers, plain carved, in solid oak, mahogany, rosewood, or walnut frame, double basil ring, and polished-edge plate glass, of the very best construction and superior engraving, as figs. 158 and 158* 5 5s. 6. 6s. to 8 8 Dial Barometers, 10, 12, and 14-inch, of the very best construction, in richly carved solid frames of Gothic, Mediaeval, Elizabethan, Egyptian, Chippendale or other designs, in Oak, Mahogany, or Walnut-wood (figs. 159 and 159*) . / 10 10s. 16 16s. to 25 Suitable for Club-houses, Mansions, &c. N.B. DIAL BAROMETERS required for transmission to distant parts, such as India or the Colonies, should be ordered expressly, as in that case they will be rendered portable by plugging the tube as described page 135, and shown in diagram fig. 135. The prices quoted for the more elaborate forms of Dial Barometers are subject to variations dependent upon the amount and quality of the ornamental carving and engraving. 45, COBNF1ILL, E.G., AND 122, BEGENT STREET, W., LONDON. 139 PEDIMENT BAROMETERS. NEXT to a Standard instrument the Pediment Barometer must be regarded in a scientific point of view as the most accurate form of Barometer, the actual weight or pressure of the atmosphere being exhibited by the varying length of the mercurial column itself, subject to a few corrections that need not be noticed by ordinary observers. At pages 2 and 3 will be found the general principles of the straight tube or Pediment Barometer. The cistern of the Pediment Barometer is made of boxwood, with sufficient internal area to allow of a fall of at least two- thirds of the mercury contained in the tube when the Barometer is in action without materially interfering with the correctness of the readings. It should also contain sufficient mercury to prevent air passing up into the tube. The bottom of the cistern is formed of flexible leather, so as to admit of the use of a screw to render the Barometer portable, as described in the paragraph Standard Barometer, pages 4 and 5. It will be seen that most of these Barometers are furnished with two Verniers, or indices. The use of the second Vernier is to record on the left hand scale of the instrument the previous reading of the Barometer, and show at a glance any alteration that may have taken place by the difference of the readings of the two Verniers. In taking a reading or observation by the Pediment Barometer the Vernier carrying the Index Pointer is to be moved gently up or down, until its edge is exactly in a line with the centre of the top of the mercurial column as shown in fig. 5, page 6. If when adjusted the edge of the index is exactly in a straight line with, say, the division marked 30, then the height or length of the mercurial column is exactly thirty inches. The value of this column is given on pages 4 and 5 ; also on pages 6 and 7 will be found a description of the use of the Vernier, especially at the foot of page 7, where the Vernier of the ordinary Household Barometer is spoken of as subdividing the inch scale into hundredths. If the division 1 in the Vernier coincides with the line at 29 inches on the scale, then the reading would be 29'11; if division 2 coincides with the line below that marked 29 inches, then the reading would be 29'12 ; that is twenty- nine inches and eleven hundredths or twenty-nine inches and twelve hundredths, or it may be read twenty-nine inches one tenth and one hundredth, and so on. The allowance to be made for height of the Station above the sea-level is, as stated by Admiral Fitz-Roy, as under. The average height of the barometer, in England, at the sea-level, is about 29*94 inches, and the average temperature of air is nearly 50 degrees. Every ten feet of elevation above the sea lowers the Barometer about ten or eleven thousandths of an inch. Add one-tenth of an inch to the observed height for each hundred feet the Barometer is above the mean sea-level. This sea-level should be that of the ocean itself, at mean half-tide, a level which should be the universal standard line of reference. The Thermometer falls about one degree for each three hundred feet of elevation above more than fifty feet from the ground. 140 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, B.C., PEDIMENT BAROMETERS. FIG. 168. FIG. 169. FIG. 168*. 45, CORNHILL, E.G., AND 122, EEGENT STEEET, W., LONDON. FIG. 165. FIG, 161. FIG. 164. FIG. 163. FIG. 164*. PORTABLE PEDIMENT BAROMETERS. 160 Model Barometer, with vernier and thermometer, also screw, to render it portable ...... 161 Pediment Barometers, with ivory scales, thermometer, SLIDING VERNIER, the tube visible throughout the whole length, and portable screw, (fig. 161) 162 Pediment Barometer, with glass cover over the face, rackwork vernier and thermometer, exposed tube 163 Portable Pediment Barometer, Round Top Frame in, Oak, Mahogany or Rosewood, the tube covered entirely, rackwork Yernier, and a Thermometer on the front (fig. 163) ... .... 164 Ditto ditto, with Square Moulded Top, large tube, and one Yernier (figs. 164 and 164*) 165 Ditto ditto, with extra large tube, 2 rackwork verniers, ivory scales, with Thermometer, in Oak, Mahogany, Walnut, or Rosewood frame (fig. 165) .... Each. s. d. 220 Each. s. d. 110 2 10 2 15 330 3 10 4 10 550 660 142 NEGRETTI AND ZAMBRA, HOLBORN YIADUCT, E.G., FIG. 166. FIG. 167. FIG. 167A. FIG. 167B. FIG. I67c. FIG. 167D. Each. 166 Portable Pediment Rosewood Barometer, elegantly inlaid with pearl or metal, thermometer in front, ivory scale, rackwork vernier (fig. 166) fitted up to order 770, 167 Portable Pediment Barometers, with two Verniers, best Carved oak, Rosewood, "Walnut, or Mahogany frames, of various elegant designs, fitted up in the very best manner (figs. 167 and 167 A, B, c, D). with Opal Glass or Ivory Scales 6 6s. 8 8s. 10 10 168 Large Pediment Barometers, handsomely mounted in Oak, Walnut, or Ebonised frames, the tube of large internal diameter, and the cistern presenting a large area, to insure uniformity in reading, Ivory, Opal Glass, or Silvered Metal Scales, with engraved ornamental letters and two Yerniers (figs. 168 and 168*) 8 8s. 10 10s. 12 12s. 15 15 169 Ditto ditto, Ebonised Wood frames with Ivory or Opal Glass Scales, and two Yerniers very handsomely carved (fig. 169) . . 1818 to 26 Extra sized Pediment Barometers, suitable for Public Institutions or Club Houses, specially designed and made with English or French and English Scales to order. A large and varied Stock of Household Barometers will always be found at all of Negr.etti and Zambra's Establishments. 45, COENHILL, E.C., AND 122, REGENT STREET, W., LONDON. 143 FIG. 171. 170 The FITZ-ROY STORM BAROMETER, or FISHERMAN'S and LIFE BOAT STATION BAROMETER, as made by Negretti and Zambra especially for the Board of Trade and Royal Life Boat Institution, to be fixed at all the principal Seaports, Fishing and Life Boat Stations. fig. 170. Price, 5 5s. This Barometer consists of a tube with very large bore, and an accurate Thermometer, mounted in a solid oak frame, firmly screwed together, with scales and figures, &c., permanently engraved on Porce- lain, by Negretti and Zambra's Patent process, the Vernier reading to 100-ths of an inch. It is strongly recommended as a good, sound working instrument, admirably adapted for use in Public Institutions. Extract from, Admiral Fiti-Rc^fs Reports of the Meteorologio Office of the Board of Trade, 1864 : "In my last Report, I stated how highly the Board of Trade ' Fishery ' Barometers have been valued on the coasts. They are now eighty in all, specially lent, under due control and care. Two only of this number have become slightly defective, and have been exchanged . Not one has been injured in carriage, singular to say, between Cornwall and the Shetland Isles, Ireland and Yorkshire. It may be more readily estimated mentally than accurately proved, to what extent these simple instruments (all reliably madef and tested) have already been the means of saving life and property. Explanatory manuals and blank forms for diagrams have been extensively circulated among the coasters and fishermen, who are all, now, much influenced by, and very thankful for, the benefits of this act of their Government. Many are the local in- stances of similar beneficence by individuals especially the Duke of Northumberland, who has placed no less than fourteen barometers." Messrs. Negretti and Zambra would specially caution the Public against purchasing cheap and worthless imitations of Admiral Fitz-B-oy's Barometers as leading to disappointment. Full details both as to the construction and use'of the true Fitz-Roy instrument will be found in Negretti and Zambra's Barometer Manual, compiled by Admiral Fitz-Roy for the Board of Trade ; post free, 6d. 171 Fitz-Roy Barometers with two Verniers . . 6 10 172 Ditto ditto, in Ornamental Carved Oak, Walnut, or Mahogany frames (fig. 168*) . .880 Barometers in solid frames, mounted wilh Ivory or Opal Glass Scales, having the Fitz-Roy Weather Rules on one side and the ordinary words, Fair, Change, Rain, and Stormy on the other, at the same prices as No. 168*. These instru- ments are very suitable for Public Institutions. t By Messrs. Negretti and Zambra. NEGBETTI AND ZAMBEA, HOLBOEN VIADUCT, E.G., FIG. 173. 173 Negretti and Zambia's Faimer's Baiometer, for ascer- taining the humidity of the atmosphere, the general character of the weather, and the approach of wind or rain. The Farmer's Barometer combines three distinct instruments the Barometer, the Thermometer, and the Hygrometer, and is equally valuable to the Agriculturist and the Invalid, a difference of 5 to 8 being considered a healthy amount of moisture in the air of dwelling rooms. The action is very simple, and so long as a sufficient supply of water is kept in the cistern, the Hygrometric condition of the atmosphere can be known at any moment. It is a well-known fact that the Barometer is as much, or even more affected by a change of wind as it is by rain, and the ob- jection raised against a simple Barometer reading, as leaving the observer in doubt whether to expect rain or wind, is entirely re- moved in the instrument now offered to the Public by the addition of the Hygrometer, an instrument indicating the comparative degree of dryness or dampness of the air ; a most important item in the determination of the coming weather. Hitherto the use of scientific instruments of this class has been confined to very few observers. Nevertheless, through the instrumentality of James Glaisher, Esq., F.R.S., as Secretary of the British Meteorological Society, multitudes of observations have been taken with extreme accuracy, and duly registered ; and it is from these carefully collected data that we are enabled in a measure to interpret the various changes that we feel and see going on in our atmosphere, and by the aidj of well-con- structed instruments, are in a position to predict with a great degree of certainty the weather that is likely to prevail from time to time. Instructions for using the Wet and Dry Bulb Hygrometer will be found at page 77. And at page 76 will be found a table giving the value of Hygrometric readings in a simple form, sufficient for the use of ordinary observers. The Fanner's Barometer as fig. 173 .... 2 10s. Ditto, ditto, in Ornamental Mountings 5 5s. 6 6s. 174 Negretti and Zambra's Miners' Barometer. It having been observed, that explosions of gas in mines mostly occur when the Barometer is very low (showing diminished atmospheric pres- sure), it is important that a good Barometer should be at hand, for observation by the Managers and others. For this purpose Negretti and Zambra make strong and sufficiently accurate Barometers, as fig. 174, at . . 1 Is. 2 2s. 3 3s. 175 Aneroid Barometers for Miners' use, exceedingly convenient and sensitive, with Extended Scale 2 10s. 3 10s. 4 4s. 176 Miners' Pocket Aneroids, see also page 143. 3 3s. 4 4s. 5 5s. STANDARD AND MOUNTAIN BAROMETERS (see pages 1 to 13). 45, COENHILL, E.G., AND 122, EEGENT STREET, W., LONDON. 145 FIG 174. FIG. 177. FIG. 181. FIG. 180. FIG. 179. MARINE BAROMETERS. 177 Marine Barometer, plain mahogany frame, with Ivory scales, sliding vernier, Thermometer, and Brass arm gimbal, for suspension (fig. 177) 178 Marine Barometer, round, moulded, or carved top, with rack- work to vernier, Thermometer, capillary tube to prevent the ingress of air into the column, even during the most violent oscillations of a storm, Brass arm gimbal, &c. ....... 179 Ditto ditto, in Carved frame (fig. 179) .... 180 Marine Barometer, best mounted as fig. 180 . 181 Marine Barometer, best, with SYMPIESOMETER in front ; the sympiesometer constructed and laid off with the greatest accuracy by actual experiments, Brass gimbal, &c. (fig. 181) 182 Board of Trade Standard or Kew Marine Barometer, figs. 16 (seepage 11) and 182. 183 Fitz-Roy's Marine Gun Barometer, fig. 183, (see page 12). Each s. d. Each. s. d. 220 2 10 660 146 NEQEETTI AND ZAMBBA, HOLBOEN VIADUCT, E.G., FIG. FIG. 186. FIG. 187. FIG. 184 Sympiesometers. Previous to the invention of the Aneroid Barometer, the Sympiesometer, from its extreme sensibility and con- venient size, was much used for Marine observations ; but owing to its liability to be put out of adjustment in transit, it is now rarely used except as an instrument of comparison. Being partly acted upon by the pressure and partly by the temperature of the air, its correct name would be a Thermo-Barometer. Directions for using the Sympiesometer. It should be always carried top upwards, to prevent the air mixing with the liquid. Care should always be taken to screen it from the heat of the sun or cabin fire. To ascertain the atmospheric pressure by the Sympiesometer, note first the temperature of the mercurial thermometer; secondly, adjust the pointer of the pressure scale to the same degree of temperature on the scale of the air column ; thirdly, read the height of the liquid on the sliding scale, the divisions and figures representing the inches and tenths of theJBarometer scale. Each. 185 Sympiesometer, in wood frame, with registering index and plate glass front 186 Ditto ditto, with Hackwork Movement, large size and best make, Oak or Rosewood Frame (fig. 186) . 187 Pocket Sympiesometer,* suitable for travelling, and taking altitudes, or mountain service, in leather hinged case (fig. 187) 188 Ditto ditto, in leather case with strap for Mountain service . .... s. 2 10 4 10 3 15 440 * The use of the Pocket Sympiesometer is now quite superseded by the Aneroid Barometer. 45, COENHILL, E.G., AND 122, EEGENT STREET, W., LONDON. 147 1 FIG. 190. FIG. 189. FIG 192. 189 Storm Glass or Chemical Weather Glass, for prognosticating Each. Each. changes in the weather, by sea or land, particularly high winds, storms, or tempests (fig. 189) . . .046 056 190 Ditto ditto mounted on a Boxwood Scale, with a Thermometer (fig. 190) . . . . 7s. 6d. 10 6 12 6 191 Ditto ditto . . plain Window Bracket . 12 6 192 Ditto ditto best, mounted on Window Bracket(fig. 192) 110 1 15 This curious instrument appears to have been invented more than a hundred years ago. The original maker is not known; but doubtless it is an accidental discovery of some of the old Alchemists, who were constantly experimenting with the substances composing the solution with which it is made. It is simply a long glass vial, nearly filled with an alcoholic solution of camphor, to which is added crystals of nitrate of potassa and muriate of ammonia, with a small proportion of distilled water. Air fills the upper part of the vial, the mouth of which is corked or hermetically closed. The various appearances presented in the liquid and crystals have been noticed to prognosticate atmospheric changes, and rules have been deduced from careful study and comparison of the glass and weather. Instructions for using the Chemical Storm Glass sent with each instrument. Admiral Fitz-Roy, in The Weather Book, writes of this instrument as follows : "Since 1825, we have generally had some of these glasses, as curiosities rather than otherwise; for nothing certain could be made of their variations until lately, when it was fairly demonstrated that if fixed undisturbed in free air, not exposed to radiation, fire, or sun, but in the ordinary light of a well- ventilated room, preferably, or in the outer air, the chemical mixture in a so-called storm-glass varies in character with the direction of the wind not its force, specially (though it may so vary in appearance, only from another cause, electrical tension)." Some curious information connected with the Camphor Glass will be found in two pamphlets written by Charles Tomlinson, Esq., of King's College, London, on The Move- ments of Camphor on Water, and The Motion of Camphor towards Light. From these papers it would appear that the changes observed in the Storm Glass are due solely to variations of light and heat. L 2 148 NEGEETTI AND ZAMBKA, HOLBORN VIADUCT, B.C., ANEEOID BAROMETERS. FIG. 194. FIG. 195 193 194 195 Aneroid Barometer, Metal Case about 5 inches diameter. Enamelled Card Dial, stout Glass front, in hinged Leather Case . . .2 Ditto ditto, with Silvered Metal Dial (fig. 194) . Ditto ditto, with Thermometer (fig. 195) Each. s. d. 10 300 3 10 Flu. 196. FIG. 199. 196 Boat Aneroid, the engraving fig. 196 represents the exact size of Negretti and Zambra's Pocket instrument. The metal case and the covering glass is made suitably strong for the use of Captains or Pilots of small Coasting vessels. Price, in Stout Case, 330 45, COBNH1LL, B.C., AND 122, REGENT STREET, W., LONDON. 149 FIG. 201. 197 Ship or Yacht Aneroid Barometers in strong plain Metal or ornamentally carved Wood mountings. Extreme convenience of size, combined with great sensibility and reliability, have made these instruments very popular for state cabins of Sea-going Vessels and Steam Ships. 198 Ships' Aneroids, plain Circular Bronzed Metal Mountings, with Thermometer on the dial . . 330550 660 199 Ships' Aneroids in handsomely Carved Wood Frame with Thermometer (fig. 199) 660 880 200 Ships' Aneroids, . . . smaller sizes 3 303 10 440 At pages 21 to 29 will be found a full description of the construction and use of various forms of Aneroid Barometers. 201 Negretti & Zambra's new Fisherman's Aneroid Barometer (fig. 201). No trouble or expense has been spared to obtain a trustworthy instru- ment at a moderate cost. It is mounted in a stout metal case, with a plate glass covering, the dial is of enamelled metal and 5 inches diameter. The range of scale is 26 to 31 inches, subdivided into tenths, corresponding with the scale of the Mercurial Barometer. Price, 1 15 It will be noted that at the top of the Dial is placed the word CHANGEABLE ; to the right and left of this word is printed a condensed form of Admiral Fitz-Roy's rules for prognosticating the coming weather. Should the Blue Index move to the right fine weather may be anticipated ; on the contrary, should it recede to the left, bad and stormy weather is indicated. These movements correspond with those of the Mercurial Barometer, hence the Aneroid, like the Mercurial Instrument, is said to be Rising, Falling, or Steady. 201* Negretti and Zambra's Farmers' Aneroid, mounted in frames, similar to fig. 154. 4 4s., 4 10s. 150 NEGRETTI AND ZAMBEA, HOLBORN VIADUCT, E.G., FIG. 203. FIG. 205. FIG 204. FIG. 202. 202 Aneroid Barometers, in Ornamental Mountings. Since the publication of the early editions of our Illus- trated Catalogue we have introduced the Aneroid for use as a household Barometer, mounting it in variously designed ornamental frames, suited either for the Mantel Shelf or for Suspension in the Hall or Library. Our engravings exhibit a few of the series we have had specially designed to suit these instruments. One very important advantage of the Aneroid movement thus mounted is that there is very little fear of damage in transport ; therefore these Barometers can be safely sent abroad to places where hitherto it has been almost impossible to send a mercurial instru- ment with safety; for beyond careful packing (the Aneroid does not want any screwing up or making portable) nothing is required but to unpack the instrument and hang it up, and it will at once be in action, and show the atmospheric pressure at the place where suspended. For the saloons of Sea-going Vessels and Yachts, these Aneroid Barometers are admirably adapted, being convenently small in size, and very accurate. New patterns are being constantly added to our stock, and we would observe that many of our Dial . Barometer Frames can be mounted with Aneroid Barometers instead of Mercurial Tubes. Aneroid Barometer, as fig. 203, 5-inch dial, 5 5s. ; fig. 203, 8-inch dial, 10 10s. ; fig. 204, 5-inch, 6 6s. ; fig. 204, 8-inch, 11 11s.; fig. 205, 5 10s.; fig. 205, with Clock, 10 10s. ; fig. 202, 18 10s. and 22 ; fig. 206, 6 10s. ; figs. 207 and 208, 5 5s. and 6 10s. ; fig. 209, 18 18s. ; Carved frames as figs. 158, 158, pages 136 and 138, 6 6s., 7 7s. and 8 8s. 45, CORNHILL, B.C., AND 122, REGENT STBEET, W., LONDON. 151 FIG. 206. FIG. 209. NEGRETTI AND ZAMBRA'S DESIGNS FOR LIBRARY, DINING-ROOM, OR HALL [ANEROID BAROMETERS. 152 NEGRETTI AND ZAMBEA, HOLBORN TIADTJCT, E.G., THEEIOMETEES AND HYDEOIETERS. AT pages 31 and 32 will be found described many important improvements in the construction of Thermometers invented and Patented by NEGRETTI AND ZAMBRA. Also the process for Engine- dividing the Scales and Tubes, for which a Prize Medal was awarded to NEGRETTI AND ZAMBRA at the Great Exhibition of 1851 (see fig. 31) ; a second award of Two Medals in 1862, for many important im- provements and inventions ; a Prize Medal, Santiago, Chili, 1875 ; and also a Prize Medal for Thermometers, Philadelphia, 1876. Paris, 1878, Gold Medal; London, 1883, Fisheries Exhibition, 2 Gold Medals, 1 Silver, 1 Bronze. These inventions are applied to all of NEGRETTI AND ZAMBRA'S instruments enumerated in the following List, where precise accuracy is desirable. This List will comprise Thermometers of every form and description, suited for Domestic, Medical, Horticultural, Scientific, and Manufacturing purposes, arranged as far as practicable in separate divisions. Following these are arranged the various instruments used for ascertaining the Specific Gravity of fluids, known under the general term of Hydrometers ; the whole of the instruments found under this heading with various names showing the same fact, viz., Specific Gravity, by differing scales, from the extremely light and volatile ^Ethers and Paraffins to the dense and heavy Sulphuric Acid. In the appendix to this catalogue will be found Rules for comparing the various Thermometer and Hydrometer Scales in general use. Many years of practical experience in the manufacture of Thermometers and Hydrometers in every variety of shape enables NEGRETTI AND ZAMBRA to guarantee the accuracy of these instruments, as regards testing and dividing the scales ; at the same time, careful attention is bestowed on their construction, to insure the most improved forms combined with the greatest durability. The following is an extract from a letter, received by Messrs. NEGRETTI AND ZAMBRA, written by Mr. Whipple, the manager of Kew Observatory, with reference to some Thermometers sent down by the firm for comparison. " I believe I may again assert with confidence, that we have never yet had so large a number of low range Thermometers pass through our hands exhibiting so high a degree of accuracy at the melting point of mercury." 45, COENHILL, E.G., AND 122, REGENT STREET, W., LONDON. isa THEBIOMETEKS, FIG. 221. FIG. 240. FIG. 217. FIG. 214. FIG. 213. FIG. 219. FIG. 217*. Each. a. d. Each. s. d. 210 6 or 8-inch Thermometer, Boxwood Scale ... 010 211 8 -inch ditto, with French polished scale 016 212 8-inch ditto, superior. A good reliable instrument, suited for Dormitories, Hospital wards, Wine cellars, Stables, &c. 026 213 8-inch ditto, with Enamel tube, (fig. 213) 030 214 8 -inch ditto, with Enamel tube, the scale bevelled at the edges, with double scales, either Fahrenheit and Centigrade, or Fahrenheit and Reaumur (fig. 214) .036 046 215 10-inch Best Mounted Single Scale Thermometers .056 7 G 216 12-inch best Mounted Boxwood Scale Thermometer, with double scales .... 10s. 6d. 12s. 6d. 15 110 217 8-inch, 10-inch, and 12-inch Negretti and Zambra's Patent Porcelain Scale Thermometer, strongly and neatly mounted on Oak, Very durable and suited for outdoor exposure (figs. 217 and 217*) . . 5s. 6d. 7 6 10 6 218 Ditto ditto, with Opal Glass Scales . . /s. 6d. 10 6 12 6 HALL OR DRAWING ROOM THERMOMETERS. 219 6 or 8-inch Thermometer, elegantly engraved Ivory Scale on Ebony Back, with German Silver Mountings and double scales (fig. 219) .... 10s. 6d. 12 6 16 220 10-inch ditto with very bold figures and divisions 110 221 12-inch ditto, best mounted, extra large (fig. 221) 1 10s. 1 15 2 2 154 NEGEETTI AND ZAMBEA, HOLBOEN VIADUCT, E.G., FIG. 228. FIG. 223. 224 225 226 227 Each. s. d. FIG. 226. Each. s. d. 222 10 or 12-inch Thermometers, Opal Glass Scale, with German Silver Mountings, superior workmanship, and elegant appearance, on Oak, Mahogany, or Ebonised backs, with Negretti and Zambra's Patent Enamelled Tubes, suited for Halls, Dining Rooms, Libraries, &c. (figs. 219 and 222), the divisions and figures very plainly marked. Spirit or Mercurial . 21s. 25s. 1 10 220 223 Porcelain Scale Thermometers, having extra large tubes, with very legible scales and words (fig. 223) : Single Scales. 8 -inch. Tubes filled with Mercury 12 15 8 10 12 15 20 Coloured Spirit . 6 7 6 9 6 14 6 056 066 086 12 6 150 Double Scales. 076 086 10 6 16 6 066 076 096 14 6 1 10 WINDOW THERMOMETERS FOR OUT-DOOR USE. Window Thermometers, Porcelain Scales on 10 6 12 6 Wood Brackets Window Thermometers, 8-inch Ivory or Glass Scales, enclosed in glass cylinders, on Oak Brackets, with metal tops , . . 12 6 15 10-inch ditto ditto (fig. 226) 18 12 -inch ditto ditto 150 1 10 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. FIG. 236. 155 FIG. 231. FIG. 238. FIG. 237. FIG. 247. FIG. 232. FIG. 235. FIG. 230. Each. s. d. Each. s. d. 228 229 230 231 232 233 234 235 236 Window Thermometers, 10, 12, or 14-inch, Opal Glass scales, divided by engine, and handsomely mounted on Oak Brackets, with brass supports for fixing at any angle (fig. 228) 21s. 1 10 220 PORTABLE OR POCKET THERMOMETERS. 3 or 4-inch Ivory or Metal Scale Pocket Thermometer, in morocco leather hinged case (fig. 230) 6-inch ditto ditto (fig. 230)- 8-inch ditto ditto (fig. 231) Oval Boxwood Pocket or Dressing Case Thermometer, with tube and bulb sunk in the solid Wood, to prevent breakage in travelling .... (fig. 232) Ditto ditto larger Oval Ivory ditto ditto Ditto ditto larger size (fig. 235) Negretti and Zambra's Improved Travelling Thermometer, in Metal or Silver Case (fig. 236) 4 6 10 7 10 16 1 4 10 6 110 Not larger than a pencil case; Clinical Thermometer. 237 accurately divided on its own stem. Can he arranged as a small Negretti and Zambra's Pocket Travelling Thermometer, German silver Revolving Case, and Ivory scale (fig. 237) 10 6 15 238 Ditto, ditto, .... extra large (fig. 238) 18 6 239 Pocket Thermometer in Slide Lid Wood Cases, with Ivory or Metal scale (fig. 240) ... 6s. 6d. 10 6 12 6 240 Circular Pocket Thermometer with Ivory scale, in leather hinged case, 2 inches in diameter ... 18 6 241 Ditto, 3 inches in diameter, with Compass in centre . 150 242 Ditto, 3 inches in Diameter, with Compass and Sun Dial in centre . 1 10 1 16 15G KEGEETTI AND ZAMBRA, HOLBORN VIADUCT, B.C., FIG. 243. FIG. 246. FiG. 249. FIG. 246*. FIG. 248. MANTEL OR TABLE THERMOMETERS. Each. s. d. 1 10 220 Each. s. d. 243 Boxwood Scale Thermometer, on Boxwood Stand (fig. 243) 076 10 6 244 Ivory Scale Thermometer on Ebony Stand, with glass shade 10s. 6d. 12 6 245 Ditto, on Solid Ivory stand , . . . (fig. 245) 1 12 6 246 Ivory Mantel Thermometers, handsomely engine-turned, and ornamented in numerous designs (figs. 246 &246*) 2 10 3 3 247 Ditto, with Compass or Sun Dial at top (fig. 247) . . 1 16 248 Ivory Scale Mantel Thermometers, mounted on Ebony with solid marble base (as fig. 248) 16s., 21s. 1 10 249 Marble Mantel Thermometer, as fig. 249, Obelisk and various other patterns from 1 10 250 Ditto Ditto Serpentine Marble 550 220 1 15 220 2 2s. 2 10 to 5 5 HORTICULTURAL AND BOTANICAL THERMOMETERS. 251 8-inch Botanical Thermometer, Boxwood Scale, in japanned metal cases, range of scale to 120 or 150 Q Enamel Tube 036 252 Ditto ditto ditto 10-inch 076 253 Ditto ditto 12 to 14-inch Boxwood Thermometers, do. do. 10s. 6d. 12 6 13 6 45, COENHILL, E.G., AND 122, REGENT STEEET, W., LONDON. 157 FIG. 280*. FIG. 291. FIG. 282. FIG. 267. 254 8-inch Thermometers on Negretti and Zambra's Patent Porcelain Scales, not affected by damp, &c., in japanned metal cases 255 10-inch ditto ditto .... 256 12-inch ditto ditto . 257 14-inch ditto ditto .... 258 Hot-bed Thermometer, small size, for Mushroom Beds . 259 Hot-bed Thermometer, in plain metal mounting (fig. 259) 260 Ditto ditto in mahogany frame, encased in Brass Cylinder 261 Ditto ditto, with Thermometer on the Door (fig. 261) . 262 Ground Thermometer, for ascertaining the temperature of the earth (figs. 261 and 259). See also page 34 263 Delicate Thermometers, for inserting in the stems and flowers of growing plants, divided on the stem . BREWERS' THERMOMETERS. 264 8-inch Brewers' Thermometer, Silvered Metal scales, in japanned metal case 265 10 -inch ditto ditto 266 12-inch ditto 267 14-inch ditto ditto (fig. 267) 268 8-inch Enamelled Tubes, in Copper Cases 269 10-inch ditto ditto 270 12 -inch ditto ditto .... 271 14-inch ditto ditto Each. s. d. FIG. 280. Each. s. d. 5 7 10 12 10 12 150 10 1 10 1 10 15 10 6 036 '4 6 066 10 056 066 10 12 158 NEGEETTI AND ZAMBEA, HOLBORN VIADUCT, E.C., Q FIG. 261. FIG. 269. FIG. 289. FIG. 296. FIG. 305. FIG. 298. FIG. 300. FIG. 286. 271* 8-incli Brewers' Thermometer, PORCELAIN SCALES, Each s. d. Each s. d. m 272 273 274 275 276 277 278 279 280 281 282 283 5 7 10 12 7 8 12 14 Negretti and Zambra's Patent, range of scale, 212 japanned metal cases as fig. 267 10-inch ditto ditto 12-inch ditto ditto 14-inch ditto ditto 8-inch ditto Brewers' Thermometers, Patent Porcelain Scales, in Copper Cases (fig. 267) 10-inch ditto ditto 12-inch ditto ditto 14-inch ditto ditto Best Mounted Brewers' Thermometer, extra stont scales and Scoop shape, rivetted case, as fig. 280 . Brewers' Thermometers, Best Mounted with Blind Scales, in Stout Copper cases (figs. 280 and 280*) Ditto ditto lettered instead of figured Brewers' Standard Reference Thermometers (fig. 282) . Stout Rivetted Copper Cases at a slight advance on above. Gyle Tun Thermometers, according to length, strong Wood mountings with N. and Z.'s Patent Porcelain Scales and enamelled tubes. 3ft., 36s. ; 4ft., 42s. ; 5ft., 50s. ; 6ft., 60s. 12 6 16 110 18 18 2 2 45, COBNHILL, E.G., AND 122, REGENT STEEET, W., LONDON. 159 Each. Each. s. d. s. d. 284 Vatting Thermometers, Metal Scale and Wood mountings, 3 feet stem ... 1 10 285 Ditto, ditto 4 feet do. 1 16 286 Mash Tun Thermometers, Patent Porcelain Scales in strong Metal mountings (fig. 286) 3ft., 45s. ; 5ft., 50s. ; 287 Saccharometer Thermometer with expansion scale, enamelled tube on stout Metal Mounting ... 12 6 288 Brewery Yard Thermometers Registering heat and cold. See Nos. 287 to 288 15 to 2 10 89 Malt Kiln Thermometer, stout Oak mount and Brass fittings (fig. 289+) . 10 6 12 6 BATH THERMOMETERS. BATH THERMOMETERS, WITH SILVERED METAL, OR NEGRETTI AND ZAMBRA'S PATENT PORCELAIN SCALES, IN JAPANNED METAL, OR COPPER CASES, SAME PRICE AND FORM AS BREWERS' THERMOMETERS. PAGE 157. 290 Floating Bath Thermometers, for keeping constantly in water (fig. 290) 076 291 Improved form of ditto ditto, with Porcelain Scale'(fig. 291) 15 292 Bath Thermometer (fig. 292) Porcelain Scale in strong Wood mounting) 12 6 293 Daury Thermometers, with Ivory and Boxwood Mountings 086 294 Dairy Thermometer N. and Z.'s Patent Porcelain Scales with Silver Mountings 12 6 15 295 Ditto ditto in Isolated G-lass Tube 3s. 6d. 5 6 076 The Isolated Thermometers are made entirely !of glass, and moderate in price ; they are easily cleaned, and eminently adapted for common dairy, nursery, or culinary purposes. CHEMICAL AND SURGICAL THERMOMETERS. 296 Chemical Thermometers with Plain Boxwood Scale, graduated to 300, the bulb projecting below the scale (fig. 296) 056 297 Ditto, with Brass hinge jointed Boxwood scale, to 300 . 086 298 Ditto, superior enamel tube, and French polished, 600 (fig. 298) 12 6 299 Chemical Thermometer, graduated on stem for inserting in the tubulure of Retorts, to 400 .... 056 300 Ditto ditto to 600 (fig. 300) 076 301 Ditto, best make Enamelled tube, and engine divided . 10 6 302 Ditto ditto, very finely divided to half degrees and tenths 15 110 303 Standard Thermometers (fig. 282) see page 32 .. 220 304 Thermometers Isolated hi Glass Cylinders, for Acids or Corrosive liquids 40 to 300 056 305 Ditto, ditto 40 to 600 (fig. 305) 076 306 Thermometers of extreme delicacy, various forms, for Physical investigation 10 6 15 307 Ditto, Negretti and Zambra's patent Self-registering ditto 0106 110 160 NEGEETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., NEGRETTI & ZAMBRA'S IMPROVED PATENT CLINICAL THERMOMETERS. FIG. l. FIG. 2. 308 THE importance of ascertaining and watching carefully the variations of tem- perature in disease is now daily becoming more apparent. Hitherto one of the great drawbacks to the general use of Thermometers by Medical Men has been the fact that sufficiently portable and reliable instruments have not been obtainable, the bubble of air used in Aitken's Thermometer being frequently found to be shaken out, and the instrument disabled, when its use has been most urgently needed. This difficulty is now overcome in the Clinical Thermometers invented and manufactured by Messrs. Fegretti & Zambra ; they are, in fact, a portable form of NEGRETTI AND ZAMBRA'S PATENT STANDARD MAXIMUM THERMOMETERS, universally adopted in all parts of the world. The important advantage of this Clinical Thermometer is the Indestructible Index nothing except breakage dis- turbing the reliabilty and accuracy of its indications for the Column of Mercury itself forms the index (without any intervening air-bubble or needle) simply shaking down the mercury below the divisions on the tube after use at once adjusts the Thermometer ready for future observation. Thus the Practitioner may now with the greatest confidence and convenience carry about with him a valuable aid in Physical Diagnosis, without any fear whatever of his Thermometer failing at a critical moment, all other Clinical Thermometers being subject to the defect of having their Indices shaken down into the bulb by concussion in carrying about, and thus rendered useless. DIRECTIONS FOR USING NEGRETTI & ZAMBRA'S PATENT CLINICAL THERMOMETERS. Holding the instrument firmly, with a rapid swing of the hand and arm shake or jerk down the column of mercury until it sinks below the line of divisions on the stem of the Ther- mometer, as shown in Fig. 1, at 90. The instrument is now ready for use, and being applied to the body of the patient for a sufficient time, will indicate the maximum tempe- rature by the position of the top of mercury in the tube, as seen in Fig. 2. It is not requisite that this Thermometer be read off whilst in contact with the body of the patient, for it may be removed and laid aside until a convenient opportunity occurs for noting its indication. These Thermometers are divided to Fahrenheit's scale, each degree being subdivided into fifths, or by the Centigrade scale, sub-divided into tenths. 5, CORNHILL, E.G., AND 122, EEGENT STREET, W., LONDON. 161 FIG. 309. GENERAL REMARKS. I. The index must be set before commencing to take an observation. [N.B. The index is a portion of mercury detached from THE COLUMN IN THE STEM OF THE INSTRUMENT.] . 1. After the index has thus been set, the bulb of the instrument may then be applied to the axilla, or any part which is completely covered ; and, being retained in close apposition with the surrounding soft parts for a period of not less than three minutes, the instrument is to be carefully and gently removed, when the top of the index i.e., the end furthest from the bulb will denote the maximum temperature during the period the instrument has been in perfect contact with the patient. II. THE OBSERVATIONS ought to be continuous daily, and regularly taken at the same hour every day throughout the whole period of sickness. The most useful periods for observation are 1. Between 7 and 9 o'clock in the morning ; 2. At noon; 3. Between 5 and 7 o'clock in the evening ; 4. At midnight. III. In all observations of temperature, the Pulse and the Respirations should be noted at the same time. The normal temperature of the human body, at complete sheltered parts of its surface, amounts to 98'5 Fahr., or a few tenths more or less; and a rising above 99'5 Fahr., or a depression below 97*3 Fahr., are sure signs of some kind of disease, if suck increase or depression is persistent. The average temperature of the trunk of the body in the Tropics is nearly one degree higher than in temperate regions. The increase of temperature above 99 Fahr., as measured by the Thermometer, is the best index of the amount of fever present in any disease. The temperature of the body in disease is much more readily and rapidly influenced than either the pulse or the respiration. The co-relation of the pulse, respiration and temperature, is of the utmost importance to be known in many diseases. For example, in Pneumonia, if the mean of the temperature is not above 104 Fahr., and that of the pulse is not above 120 in a minute, and the mean of the respirations not over 40 in the same time, the case must be considered a slight one ; and if the patient is otherwise healthy he will surely begin to get well in from 8 to 10 days, without any medical treatment beyond attention to diet and rest. Each disease which runs a definite course (e.g., scarlet fever, measles, small-pox, typhus fever, typhoid fever, rheumatism, avute phthisis, and the like,) has a characteristic and dis- tinctive range of temperature. FIG. 309*. Printed instructions for use given with the Clinical Thermometers, and further par- ticulars of their practical application may be found in " Aitken's Science and Practice of Medicine" 162 NEGEETTI AND ZAMBBA, HOLBOEN VIADTJCT, E.G., FIG. 310*. PRICES OF NEGRETTI & ZAMBRA'S CLINICAL THERMOMETERS. 310 Clinical Thermometers, of large size for Hospital use, in Mahogany case Clinical Thermometer, 4, 5, 'or 6-in., long, straight, self -registering, in pocket case as figs. 1 and 2 . Ditto ditto, with Magnifying Index Sterling Silver Case for ditto extra (fig. 310*) .... German Silver Case for ditto ,, . . . . . Clinical Thermometer, curved, in hinged leather case Pair of Clinical Thermometers, 1 straight and 1 curved, in hinged leather case (fig. 309) Kew Certificate of Clinical Thermometer, extra Each. s. d. 076 Each. s. <} 150 7 10 0- 5 1 10 Clinical Thermometers with Centigrade Scales at same prices as above list. 311 312 12 6 FIG. 312. Veterinary or Cattle Plague Thermometers, large and strongly mounted, in stout Pocket Case Ditto, ditto, in ditto, with Metal Protecting Sheath (fig. 312) 14 These Thermometers are a large form of Negretti & Zambra's Clinical instruments, and are identical in their construction and use. Disinfecting Thermometers ; see Special Thermometer Section. HONORARY AWARDS TO NEGRETTI & ZAMBRA. 1851. Prize Medal for Meteorological Instruments, London. 1855. " Honourable Mention." Paris Exhibition, The " Austrian Gold Medal." 1862. Two Prize Medals, London. 1875. A Prize Medal. Santiago, Chili. 1876. Three Prize Medals, Philadelphia. 1878. A Gold Medal, Paris. The only Gold Medal awarded for Meteorological Instruments in the British Section. 1881. Silver Medal, Norwich. 1882. Silver Medal, Edinburgh. 1883. 2 Gold Medals, 1 Silver, 1 Bronze, Eoyal International Fisheries Exhibition, London. 1883. A Gold Medal, Buitenzorg, Batavia, Java. 1884. International Health Exhibition, London, 3 awards and Gold .Medal. SELF-REGISTERING THERMOMETERS FOB HEAT 313 Rutherford's Maximum Thermometer, on Boxwood or Metal scale, with Steel or Graphite index 056 314 Phillip's Maximum Thermometer, on Boxwood Scale, with Air Index . * 315 Ditto ditto, on Negretti and Zambra's Patent Porcelain or Metal Scale 076 10 6 10 6 12 6 45, CORNHILL, E.G., AND 122, KEGENT STREET, W., LONDON. 163 o fl ',,,,,',, ,' ,' , ' ' ,.', .',,.',,,, ,',,' , i ' 1 '"' ' ' J ----- L ^-' 1 '' ' "-^- l '". i '"'''"" 1 " 1 "" Tiirnuiriiiii 7 ^^^^ Jik to o ID 70 so 40 so 60 70 eo 30 loo "no" iio iso PATENT FIG. 317. Each. Each. s. d. s. d. 316 Negretti and Zambia's Patent Maximum Thermometer,* on Boxwood Scale .... 10 6 Ditto ditto, Patent Solid Porcelain Scale . 10 fi Ditto ditto, Patent Porcelain, or Zinc Scale in Japanned Metal Case 10 6 317 Ditto, ditto, on Negretti and Zambra's Metal Scales with Oak mounting, (fig. 317) 12 6 SELF-REGISTERING THERMOMETERS FOR COLD. o 10 20 30 ^0 50 60 70 30 J?0 100 110 /20 ^16^ ^g^ LONL'ON ^ e PATENT FIG. 322. 318 Minimum Thermometer, Rutherford's, on Boxwood or Metal Scale 3s. 6d. 5 6 076 319 Ditto, ditto, superior mountings 10 6 320 Ditto, on Negretti and Zambra's Patent Solid Porcelain Scale 10 (y 321 Minimum Thermometer, mounted on Negretti and Zambra's Patent Porcelain or Zinc Scale in a Japanned metal Case ....... 10 6 322 Ditto ditto, on Metal Scales with Oak mounting (fig. 322) 12 6 323 Negretti and Zambra's Vertical Minimum Thermometer, a most convenient Window instrument for exhibiting Present and Lowest temperature 12 6 15 * This Instrument is the only Maximum Thermometer that can be recommended, as unless it he broken it cannot be put out of adjustment ; all others are liable to become defective in transit. It is fully described under the head of Standard Maxima Thermometers, pages 36 and 38, and at page 45 will be found particulars of the construction and use of Minima Thermometers. 11 2 164 NEGRETTI AND ZAMBRA, HOLBOKN VIADUCT, E.G., 324 FIG. 324. NEGRETT1 AND ZAMBRA'S CELEBRATED HORTICULTURAL SELF-REGISTERING THERMOMETER. For determining the greatest cold during the night or absence of the observer- This instrument is a Spirit Minimum Thermometer, similar in construction to No 53, page 45. The lowest temperature being recorded by a black glass index floating in the spirit. The scale is made of stout zinc, enclosing the tube ; the figures and divisions being boldly marked for quickly and easily reading the indications. (fig. 324) Price, 3s. 6d. Strongly recommended in all the leading Horticultural Journals as the cheapest and best registering thermometer of the kind for garden purposes. Many hundreds of grosses of these registering thermometers have been sold, giving universal satisfaction. Instructions for use given with each instrument. SELF-REGISTERING- THERMOMETERS FOR HEAT AND COLD. One of the most elegant and ingenious Registering Thermometers is that invented many years back by James Six, Esq., of Canterbury.* It records the highest and lowest temperature (or heat and cold, as it is commonly termed) during any given period of time in an exceedingly simple and convenient manner, and also at any moment showing present temperature. 325 NEGRETT1 & ZAMBRA'S IMPROVED SIX'S SELF-REGISTERING THERMOMETER FOR HEAT AND COLD. Consists of a long cylindrical bulb united to a smaller tube of more than twice its length, bent round each side of it in the form of a syphon, and ter- minating in a small pear-shaped bulb, as shown in the engraving (fig. 325). The lower portion of the bent tube is filled with Mercury ; and the long bulb, the upper parts of the tube, and part of the small bulb, with highly-rectified Alcohol. In the tubes will be found two steel needles or indices, terminated at top and bottom with a bead of glass, to enable them to move with the least possible friction. These needles would, from their weight, rest upon the mercury ; but each has a fine hair tied to its upper extremity and bent against the interior of the tube, acting as a spring with sufficient elasticity to keep the index supported in the spirit at any point to which they may be raised in the tube by the mercury. The instrument acts as follows : A rise of temperature causes the spirit in the long bulb to expand, and pressing the mercury down the left-hand tube causes it to rise in the opposite one, raising the index with it until the highest temperature is attained. The lower end of the index then indicates upon the engraved scale the Maximum temperature. As the temperature falls, the spirit and the mercury contract, and in returning towards the long bulb the opposite index is carried up by the mercury until the lowest temperature occurs, where it is left indicating upon the scale the Minimum temperature. FIG. 325. * See " Philosophical Transactions " for the years 1782 and 1790. By some writers the name is spelt Size, and of Colchester. 45, COENHILL, E.G., AND 122, KEGENT STKEET, W., LONDON. 165 The scale on the right hand is an ascending one, and on the left descending, as will be seen in our engraving (fig. 336). The thermometer is set for observation by drawing the indices down to the surface of the mercury by a small magnet, which attracts the steel through the glass, so that it is easily moved up or down. They should be drawn nearly to the top of the tubes when it is desired to remove the instrument, which should be carefully carried in the vertical position ; for should it be inverted, or laid flat, it may become put out of order. For transmission by ordinary conveyances, it requires that attention be given to keep it vertical. Six's Registering Thermometers should be always hung strictly in the shade. These Thermometers, when carefully made and adjusted to a standard thermometer, are recommended as very convenient for ordinary purposes, where strict scientific accuracy is not required. FIG. 333. FIG. 331. FIG. 335. FIG. 336. 326 Six's Registering Thermometer, 8-inch Boxwood Scale, E s ach d plain tube .... 327 Ditto ditto, enamelled tube . ! ! 328 Ditto ditto, with bevelled edges . 329 Ditto with 8-inch Zinc or Boxwood scale, in Japanned Metal case . 330 Ditto ditto, 10-inch .'.!". 331 Ditto ditto, 12-inch, Porcelain Scale (fig. 331) 332 Six's Registering Thermometers, with Opal Glass scales, in japanned Metal cases (figs. 331 and 336) 12s. 6d., 21s. 1 Copper cases, 3s. extra. Each. s. d. 076 086 10 6 10 15 1 1 10 22 166 NEGEETTE AND ZAMBEA, HOLBOEN YJADUCT, E.G., 333 334 335 336 Each. & s. d. Each. s. d. 340 341 Six's Registering Thermometers, with Opal Glass Scale, and the divisions and figures enamelled and burnt in, mounted on Oak and other woods, suited for Halls, Libraries, Dining rooms, &c. (fig. 333) 15s., 21s. 1 10 220 Six's Thermometers, with NEGRETTI AND ZAMBIA'S Patent Bulbs 25s. Six's Registering Thermometers, Opal Glass scales, fitted on Bronzed Metal brackets and Oak or Mahogany board for suspending outside a window, (fig. 335) 25s. Six's Thermometers with extra large size Patent Porcelain or Opal Glass Scale, and very legible figures and divisions (fig. 336) and Various Mountings . 1 10 250 330 330 3 10 FIG. 337. 337 Negretti and Zambra's small size Patent Maximum and Minimum Thermometer. The Tubes divided on the Stem, arranged in a mahogany case, suited for travellers to whom bulk and weight is an object (fig. 337) Pocket-size ...220 338 Ditto ditto, larger Standard size, see also page 51 . . . 2 10 FIG. 339. 339 Day and Night Registering Thermometer, Rutherford's,* on a Boxwood scale, with a Magnet (fig. 339) 15 1 10 too no m wo sn sc 70 to so 40 FIG. 340. Day and Night Registering Thermometer, with Cylinder Bulbs and enamel tubes of large internal diameter. The Maximum Thermometer, Negretti and Zambra's Patent arrangement, and each tube mounted on a separate scale, but joined together with a screw in order that the Thermometers can be used either combined or alone (fig. 340) . . . .220 Negretti and Zambra's large sized Maximum and Minimum Sea Coast Registering Thermometers, with Porcelain Scales, as constructed for Admiral Fitz-Boy ......... each 220 FOR STANDARD SELF-REGISTERING THERMOMETERS, seepages 31 to 51. * This Thermometer is very liable to get out of order, hence it is now but seldom used. 45, COKNHILL, E.C., AND 122, REGENT STREET, W., LONDON. 167 , FIG. 372. FIG. 379*. FIG. 362. FIG. 367. FIG. 364. FIG. 348. FIG. 347. THERMOMETERS FOR SPECIAL PURPOSES. , . , Each. Each. 342 Oven Thermometers for high temperatures, on heavy B . d. B . d. Cast Iron Stand to equalise the acquired temperature, range of scale about 50 to 300 P Fah 14 160 343 Ditto, Negretti and Zambra's Patent self -registering .110 1 10 342* Pit Thermometers, (Mining) Strongly mounted . .026 12 343* Dairy Thermometers, with Ivory mountings, various 344 Beehive Thermometers. See No. 235. Boxwood . 345 Soap Boilers' Thermometers 346 Dentists' Thermometers, for Vulcanising process 7s. 6d. 12 6 347 Sugar-boiling Thermometer, 3 to 4 feet long, graduated to 300, strongly mounted .... (fig. 347) 1 12 348 Sugar-boiling Thermometer, 14-inch stout metal scales, divided from 300F. to 600F. in stout rivetted Copper Cases (fig. 348) 349 Confectioners' Thermometers, isolated Glass Tubes, to 212F 350 Chemical Manufacturers' Thermometers, suited for Acid or Corrosive liquids, or general Laboratory use. See page 159, 300 to 600 ... ... See Nos. 293 to 295. 076 10 6 10 6 150 220 16 036 076 10 6 168 NEGRETTI AND ZAMBEA, HOLBOBN VIADUCT, E.G., Each. Each. s. d. s. d. 351 Confectioners' Sugar-boiling Thermometers, in Round Brass Cases, strongly mounted, range of scale 400F. to 600F 10 6 352 Vinegar Makers' Thermometers, various . . .036 056 353 Ditto ditto without any Metal mountings, as fig. 292 . 10 6 15 354 Varnish Makers' Thermometers, with strong Metal mountings, 3 feet long, form as fig. 347 . 1 16 2 2 2 10 355 Hay Stack Thermometers, or "Rick" Temperature Tester, 7 to 8 feet long, strong Iron Mounting, with N. and Z's. Patent Registering Thermometer . 1 10 Extra Thermometer for ditto 12 6 356 Boiling Point Thermometers, for determining heights by observing the Boiling point of water. See page 93 1 10 357 Alarm or Valve-regulating Thermometers, mounted on a Mahogany board or Brass stand . . . from 220 358 Thermostat or Metallic Thermometer, for similar purposes as above, an arrangement of Metallic bars of different metals made to order. 359 Leslie's Differential Thermometers, for delicate experi- ments on Radiant Heat, &c. (See page 187) . . . 1 10 220 360 Air Thermometers for ditto ditto . . . . 15 110 Boyle's arrangement, one of the earliest forms of Thermometer used. 361 Still Thermometers of various lengths and mountings figs. 379 and 347 made to order. 362 Steam Pressure Thermometers (or Thermo-Pressure Gauge), in strong Brass case (fig. 362) . . . .150 1 15 363 Ditto ditto with Hinged Door and plug for closing the boiler when the Thermometer is not in use (fig. 367) . 220 364 Hot Water Thermometers, for low pressures, small size (fig. 364) for attaching to Hot Water Warming apparatus, &c 18 140 365 Cooking or Culinary Thermometers, of various forms, see also 342 343 and 348 10s. 6d. 12 6 110 366 Fryometer, as used at the National Training School of Cookery, South Kensington. Copper Mountings . 16 6 367 Vacuum Pan Thermometers, stout Brass mounting with hinged or Revolving Door, as fig. 367 . . . .220 2 10 368 Hot Air Thermometers, for Turkish Baths, various forms 16s. 110150 1160 369 Upcast Shaft Thermometers, Self-Registering, from 50 to 600 enclosed in round Copper Case , 1 12 370 Ditto ditto, or Hot Blast Thermometer, for High temperatures in furnace shafts (fig. 372) ... 1 10 371 Registering Air Shaft Thermometers, Negretti and Zambra's Improved, for ditto ditto See page 170 . 220 372 Super Heated Steam Thermometers, with Patent Porcelain Scales, in strong japanned Iron mountings (fig. 372) 1 10 373 Ditto ditto ditto smaller size. 150 374 Super Heated Steam Thermometers, with Brass mountings, as figs. 362 and 367 220 2 10 45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 169 Each. Each. s. d. s. d. 377 Oil Testing Thermometers, for testing the Heat of Bearings, the Lubricating quality of Oils, &c., made to Order and Drawings. 378 Thermometers for Hot Rollers, ditto ditto 379 Salinometer Thermometer. See Salinometer . 066 378* Stout Copper Trial Pots for ditto, with division . 086 379* Disinf ecting Thermometers, for Hospital, Workhouse, or Mortuary use, simple form, (fig 379) . . . 16s. 150 1 16 380 Ditto ditto, Bent form, of any length of Tube or Scale to special Order and drawings. 381 Reference Standard Thermometers. See page 158, fig. 282, and page 32 . . . . . . . from 220 382 Hydrometer Thermometer, with Ivory Scale . 076 383 Saccharometer Thermometer, with Expansion Scale on Silvered Metal (fig. 348) ...... 14 384 Incubating Thermometers, Low range on long Metal Scale 98 to 100 036 385 Ditto ditto, High range, Short Metal Scale 190 to 210 . .036 386 Ditto ditto, Low range divided on the Stem 90 to 130 . .026 387 Ditto ditto, High range divided on the Stem 150 to 220 .036 388 Ditto ditto, 8-inch Metal Scale Thermometer, in japanned case 026 389 Ditto ditto, 10-inch ditto ditto, without case . . .036 390 Ditto ditto, Small Bent Tube in Metal Mounting . . .046 391 Incubating Thermometers, extra sensitive, for Experimental purposes. Made to order. 392 Thermometers, Extreme Low range, for Refrigerating Chambers, ditto ditto. 391* Petroleum Testing Thermometers (fig. 391*) 10 6 393 The Elaeometer, for testing Olive oil or Oil of Almonds. The O at the bottom of the scale is the point at which this instrument floats in Pure Oil of Poppy Seeds. The point at which it floats in Pure Olive Oil is made the 50th degree, and the space between these two points is divided into 50 equal parts and numbered accordingly. It floats at 38 or 38| Q in Pure Oil of Almonds. Price, 5s. 6d. 394 COMPARISON OF THERMOMETER SCALES. Fahrenheit. Centigrade. Eeaumur. 4-212 +100'0 + 80'0 100' 37-8 30-2 50' 10- 8-0 32- 0-0 0-0 -i-10- -12-2 -9-8 0- -17-8 -14-2 -10- -23-3 -18-6 -20- -28-9 -23-1 -50- -45-5 -36-4 -70- -56-6 -45-3 Value of one degree of these Scales. 1 Fahrenheit = Centigrade = % Reaumur 1 Centigrade = 1-8 Fahrenheit = 0'8 Reaumur 1 Reaumur = 2-25 Fahrenheit = 1-25 Centigrade Elementary Meteorology, B. H. SCOTT, F.R.S. 170 KEGRBTTI AND ZAMBRA, HOLBORN" VIADUCT,, E.C., FIG 395. FIG-. 395. FIG. 396. 395 Paraffin Testing Apparatus, with Thermometer and Spirit Lamp B . a. (fig. 395) 15 6 Fig. 395 shows a simple Apparatus for testing Petroleum to ascertain the temperature at which it gives off inflammable vapour. It consists of a sheet-iron vessel to hold the Petroleum to be tested ; this is placed in an outer vessel to hold water (somewhat in the manner of an ordinary gluepot) with a metal support, so arranged that the water can be gradually heated by a Spirit {Lamp, and the temperature of the Petroleum conveniently observed by a reliable Thermometer. 396 Petroleum Testing Apparatus, for testing the Flashing Point of Illuminating Oils. Sir Frederick' Abel's Government Pattern, as supplied to the Government Inspectors under the Petroleum Act, 1879. Complete in Box, for use with Oil or Gas only (fig. 396) 6 10 Do. do., arranged for use with either Oil or Gas . 7 10 Including Verification at Standard Department. An Act to continue and amend the Petroleum Act, 1871. [August llth, 1879.] 1. This Act may be cited as the Petroleum Act, 1879. This Act shall be construed as one with the Petroleum, 1871, and together with that Act may be cited as the Petroleum Acts, 1871 and 1879. 2. Whereas by the Petroleum Act, 1871, it is enacted that the term " petroleum to which this Act applies " means such of the petroleum denned by that Act as, when tested in manner set forth in Schedule One to the Act, gives off an inflammable vapour at a temperature of less than one hundred degrees of Fahrenheit's thermometer, and it is expedient to alter the said test : Be it therefore enacted that In the Petroleum Act, 1871, the term " petroleum to which the Act applies " shall mean such of the petroleum defined by section three of that Act as, when tested in manner set forth in Schedule One to this Act, gives off an inflammable vapour at a temperature of less than seventy-three degrees of Fahrenheit's thermometer. Every reference in the Petroleum Act, 1871, to Schedule One to that Act shall be construed to refer to Schedule One to this Act. Petroleum Act of 1879 giving description of the above Apparatus and instructions for using it, price per post, 6d. 45, COENHILL, E.G., AND 122, REGENT STREET, W., LONDON. 171 FIG. 398. FIG. 399. FIG. 400*. FIG. 400. FIG. 402. NEGRETTI AND ZAMBRA'S PATENT SELF-REGISTERING MAXIMUM THERMOMETER For ascertaining Underground Temperature, the Temperature of Mines, Thermal or Boiling Springs, Air Shafts, Atmospheric Temperature, &c., &c. 397 The above engravings represent various forms of Negretti and Zambia's Patent Self-Registering Thermometers, each adapted to a special purpose ; these can be made available in many other ways not here specified. The principle on which these instruments is constructed, and the ^manner of using them, are fully set forth on pages 42 and 43. Particular instructions are supplied with each Thermometer. Fig. 398 represents a Brewer's or Drying Room Self-Registering Thermometer, by which accurate temperatures may be ascertained in positions inconvenient of access, or where Steam, Heat, or Darkness render the true readings of an ordinary Brewer's Thermometer almost impossible to be obtained. Price in Stout Copper Case, 110 Fig. 399 shows another form of the Thermometer divided on its stem, arranged in a Glass Sheath mounted on a Mahogany Board or Metal Plate, for ascertaining temperatures in Hot Air or Drying Chambers, Baths, Ovens, &c., &c., serving as a check on temperatures during absence ; or, as described pages.43 and 46, as a Marine Atmospheric Maximum Thermometer. Price, 110 398 399 172 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, B.C., 400 Fig. 400 and fig. 400* are other arrangements of this Thermometer, made by Negretti and Zambra under special instructions from Professor Everett, for the Committee of the British Association on Underground Temperatures, 401 Fig. 401 is the Thermometer, enclosed in a Glass Tube or Sheath, fitting into a hinged Copper Protecting Case ("Well Thermometer), as seen in fig. 400*. Price, 1 10 402 Fig. 402 is a Thermometer of very Slow Action for taking direct Earth Temperatures, The bulb of this Thermometer is shown in its Glass Sheath surrounded by a good non-conducting substance as suggested by Professor Everett. The Thermometer being lowered down to the desired depth by a cord, is allowed to remain a considerable time in the earth so as to attain the existing Temperature. It is then withdrawn quickly, and the reading noted, the non-conductor around the Bulb preventing any rapid change taking place for a sufficient time to ensure accuracy. Price, 18 6 See also pages 35 and 43. The Range of Scale of these Maximum Thermometers can be varied to suit the requirements of the experiments to be carried out. At the meeting of the British Association in 1872 (Brighton), Prof. Phillips when speaking on the subject of the use of his own form of Thermometer for ascertaining underground temperatures, said> " There would be difficulty in using such instruments where the light was bad, and he thought the instrument exhibited by Prot'. Everett (Negretti's Vertical Thermometer; was better adapted to the purposes of the Committee." Beneath the surface of the Earth the Temperature increases at the rate of 1 Fah. for every sixty feet. Another authority states it 1 Fah. for every forty-nine feet. The temperature for the first sixty feet is influenced by the Seasons. In deep caverns, the effect of the great heat of summer has been only felt at mid-winter, and vice-versa, the cold of winter only reaches them at mid-summer. The subjoined list of Temperatures compiled from various reliable authorities is inserted as well illustrating the above observations. Artesian Well, Hanwell, 290 ft. deep, 55 9 . Grotto del Cane, Italy. 68. Earth Yokutsk, 50 ft. deep, 18. Hecla Earth at Summit, 153. Geyser Springs, Iceland, 179. Thermal Spring, Tajurah and Shoa, 152. Thermal Spring, Island of Lucon, 174. Volcanic Mud, Jorullo, South America, 203. Ournastok Spring, Greenland, 103. Comagillas, Mexican Springs, 205. Eaux Bonnes, Pyrenees, 89. Aix-la-Chapelle Spring, Maximum Temperature. 180. Aix-la-Chapelle Spring, Spa, 143. Baden Baden Springs, Maximum Temperature, 157. Bagneres-de-Bigore Spring, 123. Mariana Springs, South America, 138. Wiesbaden Spa, 149. San Germano Bath, Naples, 181. Buxton Spring, 82. Matlock Spring, 66. Bristol Spa, 66. King's Bath, Bath, 114. Hot Pump, Bath, 116 Q . Bath Springs, Maximum Temperature 117. supposed depth, 3,350 ft. Monkwearmouth Mine, 1,500 ft. deep, 72. Consol Mine, Cornwall, 1,740 ft. deep, 93. Cumberland Coal Mine, 600 ft. deep, 66. Salt Mine, Cracow, 730ft. deep, 50 9 . Guanaxato Mines, 1,700 ft. deep, 99 9 . On page 48 of Mr. Scott's Book on Elementary Meteorology will be found a Chronoisothermal Diagram representing the Monthly Mean Temperature at Greenwich for every hour of the day through the range of years 1849 to 1868. " This diagram was devised by M. Leon Lalanne it exhibits many most interesting facts in connection with the climate of London, amongst others, that the highest mean temperature (70) only occurs in the latter part of July and between one o'clock and half-past three p.m., and the lowest mean temperature (38) is observed during the night-time from about January 5th, to March 20th. Also it will be seen that the coldest time in summer is from three to five in the morning, while in winter there is not much change between four in the afternoon and eleven in the morning. It will be also noticed how much colder the Spring equinox is than the Autumnal, for on April 1st the temperature ranges from 40 to 50 F., while on October 1st the range is from 50 to 61 F." t Prof. Everett, D.L.C., of Belfast. 45, CORNHILL, E.G., AND 122, EEGENT STREET, W., LONDON. 173 MARINE THERMOMETERS. 403 404 405 406 FIG, 407. FIG. 408. FIG. 404. FIG. 406. SELF-REGISTERING THERMOMETERS, ADAPTED FOR DEEP SEA SOUNDINGS. Board of Trade Marine Thermometer, the scale divided on its stem, Each. and mounted on Negretti and Zambra's PATENT PORCELAIN SCALES, s. d. in japanned Metal Case 10 6 ditto in COPPER CASE (fig. 404) 12 6 1 10 Board of Trade Marine Thermometer, in round Copper case . . 1 10 Johnson's Registering Metallic Marine Thermometer. The indications are obtained by the varying expansion of brass and steel bars acting upon an index on the principle of the Thermostat (fig. 401) . . . 550 For description see N. and Z.'s Treatise on Meteorological Instruments. 407 Deep Sea Sounding Thermometers, Self-Registering, the original double tube principle, as invented by Negretti and Zambra, specially constructed for and supplied to the Board of Trade and Admiralty (fig. 407). Warranted to stand a pressure of 450 atmospheres 2 10 Many have been the contrivances for obtaining correct deep sea indications. Thermometers and machines of various sorts have been suggested, adopted, and eventually abandoned as only approximate instruments. The principal reason for such instruments failing to give correct or reliable indications has been that the weight or pressure at great depths has interfered with the correct reading of the Instrument. Thermometers have been enclosed in strong, water-tight cases to resist the pressure ; but this contrivance has only had the tendency to retard the action, so much as to throw a doubt on the indications obtained by the instrument so constructed. 408 Negretti and Zambra's Small Deep Sea Sounding Thermometer, Dr. Miller's pattern in Copper Case (as fig. 403). Price 2 10s. 3 3e. The Deep Sea Sounding Thermometers (Nos. 406, 407 and 408) having all been found defective in their indications, their use is not recommended for reasons stated in pages 60 to 70. 174 NEGBETTI AND ZAMBRA, HOLBOEN VIADUCT, E.G., FIG. 414. FIG. 415. STEAM PRESSURE GAUGES. FIG. 414*. 409 The almost daily occurrence of frightful accidents from the explosion of steam boilers calls for the utmost vigilance and care from owners and employers of steam power. One of the most important precautions is that of having accurate and reliable gauges. Too much stress cannot be laid upon this point, for if, from motives of false economy, cheap and carelessly made gauges are used, their indications can never be depended upon, and their use may lead to fatal and costly results. It has fre- quently come under the notice of Messrs. Negretti and Zambra that Steam Gauges have been supplied or repaired by persons without the slightest knowledge of their construction, or having any means of proving or testing ; consequently they have been found fearfully in error, and worse than useless because unsafe. 410 Steam Gauges, Mercurial, from 10 to 140 Ibs., with union joint at either side of the frame, in polished Mahogany frame . . .2 411 Ditto, ditto, Brass ditto 3 412 Thermometric Pressure Gauge, for showing the pressure of Steam by taking its temperature (fig. 372), Iron mountings . . .1 413 Ditto ditto, Brass mountings (figs. 362 and 367) 2 414 Ditto ditto, ditto with Bent tubes, as figs. 409 and 409*, screw flanges and stuffing boxes, &c., for high pressures from 330 415 Angle Thermometers, for Yacuum Sugar Pans, Brass Mounted (fig. 415) 1 16 416 Thermometric Pressure Gauges with Temperature and Pressure Scales made of any length to order or drawings, with either English or French divisions. 10 10 45, CORNHILL, E.G., AND 122, EEGENT STREET, W., LONDON. 175 417 Negretti and Zambra's Saturometre or Thermometrical Salinometer for determining the amount of Salt held in solution in the water of Marine Boilers. It is well known that pure water boils at 212 Fahr. at the level of the sea, and if water is impregnated with salt, the point of ebullition is materially raised ; hence the water in a marine boiler can be accurately tested as to its saline properties by observing at what temperature the ebullition is taking place within the boiler. The apparatus consists of a metal reservoir attached to the boiler by a stopcock, R, and union joint, B ; this reservoir carries a thermometer. T, whose bulb, A, reaches nearly to the bottom of the chamber ; the graduations on the scale commence at 212, the boiling point of pure water. At the bottom of the reservoir is an outlet tap, S, and there is also a tap, X, inserted a little above the bottom of the reservoir, with a tube connected with it reaching nearly to the top of the interior of the reservoir. The apparatus is used as follows : the reservoir having been emptied by the tap S, it should be closed, and the taps R and X opened ; the water from the boiler will then flow into the chamber A, partly fill it, and pass out by the pipe and tap X. After the water has been allowed to escape for a few seconds, the thermometer is to be examined, and according to the temperature indicated so will be the specific gravity of the water in the boiler, or, in other words, the percentage of salt dis- solved in it. This fact is quickly and conveniently ascertained by simply opening three taps and reading the thermometer (fig. 416) . . . . 440 Our table in connection with the description and use of Salinometers (page 189) will give the relative degrees of Saltness and Temperature. Messrs. Negretti and Zambra very strongly advise the use of the Thermonietric Pressure Gauges (No. 409) in conjunction with the Mercurial and Spring Gauges as a comparative and precautionary measure of safety. When steam is generated and confined in a boiler, the pressure upon the boiling water may be twice or thrice that of the atmosphere. Experimentally it has been found, that if the pressure in the boiler be 251bs. on the square inch, the temperature of the boiling water, and of the steam likewise, is raised to 241 ; and under the exhausted receiver of an air- pump, water will boil at 185, when the pressure is reduced to 17 inches of mercury. The following table, compiled by Dr. A. S. Taylor, gives the relative temperatures and pressures up to 12 atmospheres or 180 Ibs. pressure. Water boils. Barometer 30 inches. 320 degrees Fahr. 6 Atmospheres. 327 6'5 Water boils. Barometer 30 inches. 212 degrees Fahr. 1 Atmosphere. 234 1-5 251 2 332 7 ' 267 2-5 337 7'5 275 3 342 8 285 3-5 295 4 ., 359 10 300 4-5 368 11 307 5 374 12 315 5-5 ON COMBINED STEAM. By the Hon. J. WETHERED. " In its passage through the super-heating apparatus a portion of steam is raised by the waste heat to a temperature of 500 or 600 Fahrenheit. The heat thus arrested is conveyed to and utilised in the cylinders by its action on the other portion of the steam from the boiler, which is more or less saturated, according to circumstances. The combined steam is used in the cylinder at from 300 to 450 Fahrenheit, at which steam is generally employed, The effect of using the two kinds of steam is, that the super-heated steam yields a portion of its excess of temperature to the ordinary steam, converting the vesicular water which it always contains into steam, and expanding it several hundred-fold ; whilst at the same time, the ordinary steam yields a portion of its excess of moisture, converting the steam gas into a highly rarefied elastic vapour in other words, into pure steam at a high temperature." 176 NEGEETTI AND ZAMBEA, HOLBOEN VIADUCT, E.G. HYDEOMETEES, &c. 418 HYDROMETERS, or Areometers, are instruments constructed to determine the specific gravity of fluids. Their use has been traced back to a date about 300 years before Christ, the invention being ascribed to Archimedes, the Sicilian philosopher. Their action is dependent upon the law " that a body immersed in any liquid sustains a pressure from below upwards equal to the weight of the volume of liquid displaced by such body." First on our list of Hydrometers we place those showing Specific Gravity, because all other Hydrometer scales are referable to it ; and as the figures indicated are absolute and definite quantities, or values without possibility of dispute, it is the best both for scientific and manufacturing purposes. The Specific Gravity of Fluids may simply be described in a few words. A very light glass flask is accurately adjusted and stoppered to hold exactly 1,000 grains of pure distilled water at a temperature of 60 Fahrenheit. If this flask be filled with highly rectified asther, and then carefully weighed in a delicate balance, it will be found that the flask instead of holding 1,000 grains will only weigh say 713 or 715 grains at 60 degrees of temperature. This is the specific gravity of pure a9ther, or as written in chemical language, 0*713 or 0*715. On the contrary, if the flask be filled with concentrated sul- phuric acid it will be found to hold 1842 or 1845 graine, or specific gravity, 1-842 or 1*845, at 60 degrees temperature. In these readings water is repre- sented by one thousand, I'OOO. All other fluids (save Mercury) will be found to be of intermediate specific gravity, say between 600 and 2*000. Our list embraces the whole of the Hydrometers in use in the United Kingdom and most of the Foreign instruments. The comparative value of these may be ascertained by reference to a valuable series of carefully compiled tables described at the end of Hydrometer Section. As a rule all Hydrometers made in England are adjusted to a temperature of 60 Fahrenheit, but if they are required for use in the East or West Indies, they must be specially adjusted at 84 Fahrenheit, and should be ordered accordingly. 45, COKNHILL; E.C , AND 122, BEGENT STREET, W., LONDON. 177 FIG. 419 FIG. 481. FIG. 424. FIG. 423. FIG. 436. FIG. 420. Each. s. d. Each. s. d. 419 Hydrometer from 700 to 1-000 for Specific Gravities lighter than water (fig. 419) 066 420 Hydrometer from 1-000 to 1-850 or 2-000, for fluids heavier than water (fig. 442) 066 421 Beaume's Hydrometer '0 to -70, for fluids lighter than water 050 422 Ditto Hydrometer, '0 to *40, for cane-juice and similar fluids heavier than water (fig. 422) . 050 423 Beaume's Saccharometer, Brass Gilt, for sugar boiling, range '0, '40 176 Beaume's Hydrometers are used extensively in England as well as in France, and are applicable for testing all kinds of liquids. There are two distinct instruments, one for fluids lighter than water, and the other for fluids heavier than water. The latter is for distinction called the Acidometer or Saccharometer (pvse-acide or pese-sirop), the former the Spirit Hydrometer (pese-espritj . N NEGRETTI AND ZAMBEA, HOLBORN VIADUCT, B.C., FIG. 425*. FIG. 425. s. 424 Government Proof Hydrometer, Glass, showing percentages of proof spirit from 60 over proof to 40 under proof (fig. 397) . . .056 425 Ditto ditto Hydrometer, Glass, in mahogany box with Thermometer (fig. 398) with Printed instructions for use 15 426 Ditto ditto, with Ivory sliding Computing Scale . .110 427 Sikes'* Hydrometer is the instrument used by the government officers in the collection of the spirit revenue in the United Kingdom. It is made entirely of metal, usually strongly gilt to prevent corrosion. It consists of a globular float with an upper and lower stem. The upper stem is flattened and divided into ten parts, numbered 1, 2, 3, &c. These are again sub- divided into five parts. The lower stem is tapering, and terminating by a pear-shaped bulb. There are nine weights numbered from 10 to 90, each weight being pierced in the centre, so that it can be placed on the conical stem at the smaller end and slid down towards the bulb until it becomes securely fastened. 428. Sikes' Hydrometer is adjusted to spirit Specific Gravity -825 at 60 Q Fahr., this being considered Standard Alcohol. In this spirit the instrument floats at the first division on the stem without a weight. In weaker spirit, having a greater density, the Hydrometer will not sink so low, and should the density be greater, one of the weights must be added to cause the entire immersion of the bulb of the instrument. Each weight represents so many principal divisions of the stem. Thus the heaviest weight, marked 90, is equal to ninety divisions of the stem, and the instru- ment with this weight attached floats at in distilled water. Each principal division on the stem being divided into five, the Hydrometer has a range of 500 degrees between alcohol, sp. gr. '825 and water. On one side of the upper stem, near to the division 1, will be found a line, at which the instrument will float with the weight 60 attached in spirit exactly of the strength of proof at a temperature of 51 Fahr., and if the square weight (sent with the instrument) be placed on the top of the stem, the weight 60 still being attached to the lower stem, the instrument will float at the side line in distilled water of the same temperature. This square weight being precisely one-twelfth part of the total weight of the hydrometer and weight 60, the above indication is in conformity with the definition of proof spirit stated in the act of parliament, " Proof spirit to weigh at 51 temperature exactly twelve-thirteenth parts of an equal bulk of distilled water." In using Sikes' Hydrometer, it is immersed in the spirit and pressed down to until the whole of the divided stem be wet. The amount of force required to * We have consulted several authorities for the correct spelling of this name ; Dr. Tire and Professor Redwood spell it Sikes. An act of parliament, 26th June, 1858, 18 and 19 Viet., has Sykes many writers adopt this. The same difference occurs with the name of the inventor of a Maximum and Minimum Registering Thermometer Six or Sixe. In both cases there appears to be some doubt which is correct. 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 179 FIG. 429. FIG. 429*. sink it will determine the selection of the requisite weight to be attached to the lower stem. Again immerse the hydrometer in the spirit, and allow it to float freely and settle, and then keeping the eye in a line with the surface of the spirit, notice the division cut by the surface as seen from below. The number indicated by the stem is added to the numbers of the weight, and the sum of these, together with temperature of the spirit (which should be very carefully noted) will, by reference to a Book of Tables accompanying the instrument, give the required strength per cent, of the spirit under test. The strength is expressed in numbers denoting the excess or deficiency per cent, of proof spirit in any sample, and the number itself having its decimal point removed two places to the left, becomes a factor, whereby the gauged contents of a cask of such spirit being multiplied, and the product being added to the gauged contents if over proof, or deducted from it if under proof, the result will be the actual quantity of proof spirit contained in such vessel. The commercial term above or below proof is partly derived from the govern- ment having fixed a certain strength of spirit as mentioned above as Proof Spirit by which the strength of all spirit is comparable. It is also said that the term proof is derived from an ancient method of testing the strength of spirit by pouring the sample over gunpowder in a metal cup and then setting fire to the spirit ; if, when the spirit had burnt away, the powder exploded, the spirit was said to be over proof; if , on the other hand, the gunpowder did not ignite, owing to the large portion of water left behind, it was said to be under proof. The weakest spirit capable of firing gunpowder by this method was called proof spirit, but it required a spirit of nearly the strength of what is now called rectified spirit to stand this test. The Standard Proof Spirit of the excise is defined by law (56 Geo. III. cap. 140) to be " that which at a temperature of 51 Fahrenheit's Thermometer, weighs exactly twelve-thirteenth parts of an equal measure of distilled water" This will have a specific gravity of '923 at 51 Fahrenheit, or about -920 at 60 Fahrenheit. The Standard Alcohol of the Excise is spirit of the specific gravity '825 at 60 Q Fahrenheit. By " Spirit 60 degrees over proof " is understood a spirit 100 measures of which added to 60 measures of water will form Standard Proof Spirit, specific gravity '920. By " Spirit 10 degrees under proof " is understood a spirit 100 measures of which mixed with 10 measures of standard alcohol, specific gravity '825, will form Standard Proof Spirit. NOTE. We are indebted to Professor Bed wood for most of the figures given in connection with Sikes' Hydrometer. The British Pharmacopoeia of 1864 orders that the Specific Gravity of liquids is to be taken at a temperature of 60 degrees by Fahrenheit's Thermometer, and gives the Specific Gravity of absolute Alcohol as 0795, Rectified Spirit (Spiritus Eectificatus) as 0'838. and Proof Spirit ( Spiritus Tenuior) as 0-920, at a temperature of 60 degrees Fahrenheit. N 2 180 NEGEETTI AND ZAMBEA, HOLBOUN VIADUCT, EC., 5 5 7 10 15 1 10 429 Sikes 1 Hydrometer, Double Gilt Metal, with silver soldered joints, Each. as used by the Excise and Customs, with weights, enamel tube s. a. Thermometer, Test Glass, and Book of Tables (figs. 429 and 429*) 400 430 Ditto ditto, with Comparative Rules 4 10 431 Sikes' Hydrometer Standard, Gilt Metal, 5-inch range on stem, divided to l-10ths Book of Tables for use with Sikes' Hydrometer to 80 Fahr . Ditto ditto ditto to 100 Fahr. . 432 Sikes' Pocket Hydrometer in German Silver .... 433 Ditto with Thermometer, jar and case 434 Dicas's and Allan's Hydrometers are very similar in construction to Sikes' instrument, but are now very rarely used. Saccharometer for Brewer's use. Shows the weight of wort per barrel heavier than water. Thus 36 gallons of water weighs 360 Ibs., but 36 gallons of wort of specific gra,vity 1'050, weighs 18 Ibs. heavier than water, viz., 378 Ibs. Printed instructions for use accompany each Saccharometer. 436 Brewer's Saccharometer Glass, showing pounds per barrel (fig. 436) 056 437 Ditto ditto with Extra Scale showing Specific Gravity and Ibs. per barrel 076 438 Ditto ditto Glass Testing Jar with Tables of Temperature Corrections, in Mahogany box, with Thermometer as fig. 425 . 15 6 439 Saccharometers, Glass Standard, comprising two instruments in mahogany case, one Saccharometer ranging from to 25 Ibs., and the other 25 Ibs. to 50 Ibs., very carefully adjusted . . .220 s _0 70 en -ao 20 FIG. 440. FIG. 441*. 440 Saccharometer, Double Gilt Metal, with silver soldered joints, with one weight, metal scale, enamelled tube, compared Thermometer, with expansion scale and rule, in mahogany case, with lock and key, Glass assay jar (figs. 440 and 441*), and book of directions for use . . .500 This Saccharometer can be strongly recommended both for strict accuracy and the very highest class of workmanship. 441 Saccharometer, Metal, Improved with double Scales extending from water to 25 Ibs. per barrel on one side of the upper stem, and by the use of the weight, the opposite scale will test wort from 25 Ibs. to 52 Ibs. per barrel not Gilt, Glass assay jar . . . . . . .330 Ditto, ditto, Double Gilt, including Thermometer, Rule, and Book of instructions, in box 400 442 45, CORNHILL, E.G., AND 122, EEGENT STREET, W., LONDON. 181 FIG. 444. 444 Negretti and Zambra' s Patent Saccharometers, as supplied to the Excise Department of the Inland Revenue. The changes in the scale divisions of Saccharometers, required by the New Beer Act, having been completed, Messrs. Negretti and Zanibra are now prepared to supply their Patent Glass Saccharometers, and also a new form of Brass instrument, made in accordance with the models supplied by them to the Excise Department of Inland Revenue. Negretti and Zambra having been favoured with instructions to furnish designs for special instruments, have introduced those mentioned above, each kind being of Standard accuracy, and moderate in price. Fig. 444 consists of two Patent Standard Glass Saccharometers, with strengthening rods, one with divided scale ranging from 1,000 to 1,050 Specific Gravity; the other from 1,050 to 1,100 Specific Gravity; also a brass scale Thermometer. The three instruments are fitted in a strong, well-made Mahogany Box as supplied to the Excise Price 220 A set of three Patent Glass Saccharometers, the scales ranging from 995 to 1,150, also a Brass scale Thermometer. The four instruments fitted as above 2 15 Glass Saccharometers being much more accurate than those made of metal, Negretti and Zambra strongly recommend their use, especially as the risk of breakage is now much diminished by the introduction of their Patent arrangement for strengthening the weak parts of the instruments. FIG. 445. In most of the large breweries the Standard instruments used are invariably Glass ones, as greater reliance can be placed upon them, more especially when indicating the fractional parts of gravity. Fig. 445 is a Gilt Metal Saccharometer, the scale on one side of its stem ranging from 995 to 1,025 Specific Gravity ; and on the opposite side, by the addition of a 182 NEGKETTI AND ZAMBKA, HOLBOEN VIADUCT, E.G.. Each. B. d. Poise (or Weight) is a scale indicating from 1,025 to 1,060. This also has a Thermometer supplied with it, and is fitted in a Mahogany Box, being arranged for use in Distilleries (fig. 445) Price 2 5 The same instrument is supplied with a range of scale suitable for Brewers' use, viz. : 1,000 to 1,050, and 1,050 to 1,100 Price 2 10 Messrs. Negretti and Zambra also supply a simpler form of Saccharometer, the whole range of scale being contained in one instrument. Any modification of the above arrangements can be made to suit the require- ments and convenience of purchasers. 446 Combined Glass Hydrometer and Saccharometer, 2 Scales showing Specific Gravity and Ibs. per barrel, with Thermometer, in mahogany case .... Saccharometer Thermometer, with enamelled tube and expansion scale, mounted on Silvered Brass Scale Saccharometer Can, for testing Wort, Copper, tinned inside Ditto, ditto Tin Japanned Glass Saccharometer testing or sample jars (fig 417) 450* Graduated Glass Blending Jars, for wine, spirits, or beer (figs. 450 and 441*) .... 4s. 6d. 451 Small Glass Hydrometer, specific gravity scale, with sample glass and thermometer in case (figs. 418 & 418*) 447 448 449 450 Each. s. d. 220 14 026 10 4 3 056 076 15 452 Small Glass Hydrometers in Pocket cases of various scales and range made to order. 200- 300- 400- 500 -^-j fioo- 700 800 900- FIG. 456. FIG. 512. FIG. 453. FIG. 450. FIG. 453*. FIG. 512. FIG. 462. 453 Small Glass Hydrometers, two in the set, Specific Gravity Scale, from water to sulphuric aether, or from water to sulphuric acid, in neat case with Thermometer and Test jar (figs. 453 and 342*) 1 10 454 Sets of eight small Glass Hydrometers, specific gravity, full range from tether to sulphuric acid, with Thermometer and sample jar in case . . . . . . . 456 Twaddell's Hydrometers, Nos. 1, 2, 3 (fig. 456) . '. * each 457 Ditto ditto, Nos. 4, 5, and 6 do. 458 Set of six Twaddell's Hydrometers, in mahogany case with Thermometer graduated on the stem, and test glass . . .220 10 3 4 45, COBNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 183 459 Twaddell's Hydrometers, so named after their inventor, Mr. Twaddell of Glasgow, are very largely used by Dyers, Bleachers, and Paper manufacturers, the six instruments having an extended or very open scale, figured from 0, Water, to 170, about the gravity of the strongest Sulphuric Acid. Each degree or division of Twaddell's scale being equal to five degrees of specific gravity. 460 7 Comparative Scale showing the values of Twaddell's Hydrometers, Nos. 1 to 6 in Specific Gravity. No. Twaddell's Scale. Specific Gravity. 1 to 25 1-000 to -125. 2 25 50- 1-125 -250. 3 50 75 1-250 1-375. 4 75 100 1-375 -500. 5 100 125 1-500 -675. 6 135 170 1-675 -850. Twaddell's Hydrometers if for use in hot climates are specially tested and adjusted at 84 Fahrenheit at an extra cost of 6d. on each instrument. Each. 461 Aquarium Hydrometer, for showing the density of Salt or Sea Water s - d - (fig. 424) . . .036 462 Board of Trade, Marine Hydrometers, for taking the specific gravity of Sea Water '0 to '40 (fig. 462) 056 463 Ditto ditto, 2 Hydrometers with very open scale, to 40 and 20 to 40 10 464 Sea Water ranges in Specific Gravity from-1-020 to T036, the ordinary gravity varying between T026 to 1'028. Mediterranean Sea Water about T030, and that of the Caribbean Sea, 1-040. The water of the Dead Sea has the extraordinary density of 1-200 to 1-250, the saltest water known. THE SALTNESS OF SEA- WATER. Professor Chapman, of University College, Toronto, says that the object of the saltness of sea-water is to regulate evaporation. If any temporary cause raises the amount of saline matter in the sea to more than its normal value, evaporation goes on more and more slowly. If the value be depreciated by the addition of fresh water in undue excess, the evaporation power is the more increased. He gives the results of various experiments in reference to evaporation on weighed quantities of ordinary rain-water and water holding in solution 2'6 per cent of salt. The excess of loss of the rain-water compared with the salt solution was, for the first twenty-four hours, 0'54 per cent., at the close of forty-eight hours, T46 per cent ; and so on in an increasing ratio. Analysis of sea-water taken from the English Channel : Chloride of Sodium 1891-6 Chloride of Magnesium 228-4 ' Chloride of Potassium 47*8 Iodide and Bromide of Magnesium . . . 15-4 Sulphate of Magnesia 145-4 Sulphate of Lime 94-5 Grains per gallon . 2423-1 These quantities vary with the locality as well as the percentage of - Organic Matter also found in Sea Water. The ordinary surface Temperature of the Sea in temperate climates is 45 to 51-5 Fahr. " In most parts of the world the average temperature of the ocean's superficial water is nearly that of the air upon its surface. In the tropics the temperature of the sea water ranges from 70 to 80 Fahr. or more, and the air is much the same. In some limited parts of the globe the surface water is as warm as 86 P , for instance, near the Galapagos Islands ; 184 NEGRETTI AND ZAMBEA, HOLBOEN VIADUCT, E.G., and in some very confined localities even more than 90, as for example in parts of the Eed Sea and Indian Archipelago. But although so warm on the surface it is very much colder at a few hundred fathoms below, the temperature decreasing to 35, and even less." s. d. 465 Universal Hydrometer, for all fluids from -700 to 1-900 . . . 12 466 Confectioners' Hydrometer for Ice making ... 3s. 6d. and 056 467 Ditto ditto for Syrups (see also No. 396) . . .056 468 Hydrometer for Brine. A saturated solution of sea salt varies between 1-1962 and 1-205 at 60 Fahrenheit 056 469 Hydrometer for British Wines (Roberts' scale, to 26) . . .056 470 Ditto, for Syrups (Specific Gravity) 056 471 Ditto, for Soap (Beaurne's) 056 472 Ditto, for Soap Lye (Specific Gravity) 056 473 Olaeometer, for fixed oils, such as Sperm, Linseed, Rape, &c. . .056 From a competent authority we quote the following gravities : 474 Linseed Oil , . . . 0-9347 Almond Oil . . . . 0-9180 Castor Oil . . . .09611 Palm Oil .... 0-968 Oil of Turpentine . . . 0-870 Olive Oil .... 0-9176 Rape Seed Oil . . . 0*9136 Colza Oil .... 0-9136 Nut Oil 0-9260 Whale Oil , 923 475 Acidometer, for estimating the strength of Acids (fig. 420) . .066 476 Acetometer (or Acetimeter), for Vinegar . . . . . .066 " Specific Gravity if determined by a Sensitive Hydrometer is a good test of the strength of genuine Yinegar. The following table of Messrs. Taylor is nearly correct, or sufficiently so, for commercial transactions. " Revenue Proof Yinegar, called by the English manufacturer "No. 24, has a Specific Gravity of 1*0085, and contains of real acid in 100 ... 5 1-0170 ...... 10 1-0257 .... 15 1-0320 .... 20 1-0470 .... 30 1-0580 .... 40 DR. URE." It should be observed that all Malt Yinegars contain mucilage, gluten, or saline particles, which would, to a certain extent, veil the indications of the Hydrometer ; therefore, if precise accuracy be required, recourse must be had to Chemical Tests such as will be found described in all modern Chemical Books. 477 Barktometer Glass for Tanner's use, from to 50 . . . .076 478 Ditto ditto, to 80, divided to i degrees 10 6 479 Barktometer, Gilt Metal, to 80, divided to | degrees with Thermometer, in Mahogany Box 330 480 Citrometer, for Lime or Lemon Juice, as used by the Commissioners of Customs, specific gravity scale from to 100 in two instruments for greater accuracy, complete with computing rule, and a delicate Thermometer in a case 1 16 Like Yinegar, Lime or Lemon Juice often contains a very large percentage of mucilage, so that the indications of the Citrometer should only be regarded as approximate and not absolute. We also find that by the Act of Parliament August 26th, 1867, 30 & 31 Yict., cap. 124, Lime or Lemon Juice for sbip's use is to contain " fifteen per centum of proper and palatable proof spirits." Chemical Tests must therefore be resorted to where definite results are desired. 481 Negretti and Zambra's Hydrometer with Thermometer in the stem showing density and temperature in one instrument. Fig. 481 . 1 10 45, CORNHILL, E.C., AND 122, REGENT STREET, TT., LONDON. 185 FIG. 482, FIG. 491. FIG. 486. * " ^ FIG. 489. FIG. 484. NEGRETTI AND ZAMBIA'S LACTOMETERS FOB ASCERTAINING THE DIFFERENT QUALITIES OF MILK. IT is a matter of great importance in rural and domestic economy that we have a ready means of ascertaining the Quality of Milk yielded by different cows. The richness of milk^depending upon the quantity of oil or butter, and curd or cheese which it contains, it becomes necessary that we be able to determine these quantities with facility and precision. To attain these ends, Messrs. NEGRETTI & ZAMBRA have introduced a simple form of Lactometer, by which the richness of milk may be determined by simply taking its temperature and specific gravity. The Lactometer consists of a glass ball and stem containing a graduated scale ranging from (water) to 40 Q specific gravity, adjusted to a temperature of 60 Fahrenheit. A Glass Jar and Thermometer usually accompany the instrument. 482 Lactometer of a simple form for household use. The top of the scale is marked O and W, indicating water, and at the lower end P signifying pure milk. Intermediate between these two points are marks indicating ^ milk and f water, milk and ^ water, f milk and i water. These marks must not be taken as abso- lute, for pure milk will vary in quality or density according to the particular kind of food upon which the cows have been feeding (fig. 482) . ' . .036 483 Lactometer similar to above but with an additional scale on the back showing specific gravity 050 484 Lactometer, Negretti and Zambra's Lactometer of superior accuracy, with absolute Specific Gravity scale, with printed instructions for use (fig. 484) 5 186 NEGEETTI AND ZAMBRA, HOLBOEN VIADUCT, B.C., Each. 485 Lactometer Tubes, or Creamo-meters, graduated to show the percentage of cream ; a set of six in mahogany frame . . . 16 6 486 Ditto, a set of three tubes in frame (fig. 486) . . . 10 6 489 Cream Test Jars, graduated to show percentage (fig. 489) .056 Ditto ditto, smaller . . . .036 490 Thermometer, add or subtract, for use with above. (See also Dairy Thermometers) 076 491 Lactometer Glass, with Thermometer and Test Jar, in Mahogany Box (as fig. 425) 150 492 Thermometers for Dairy Use entirely mounted in glass (fig. 492) 3s. 6d. and 056 493 Lactometer, Gilt Metal, Specific Gravity Scale . . . 12s. 6d. 1 5 494 Ditto, ditto Gilt Metal with Thermometer and Test Jar, in Mahogany Box (as fig. 425) , .220 495 Centesimal Galactometer, Glass (Dr. HassaU's) . . . . 10 6 Lactometers being adjusted to a temperature of 60 Fahr., all trials must be made at that temperature. Should, however, that be inconvenient, then for every five degrees of diiference in temperature, make a difference of one degree on the Lactometer scale, adding the degrees of temperature if above 60, and subtracting them if below GO . For greater convenience, Thermometers are made by NEGRETTI and ZAMBRA to show at a glance the amount to add or subtract for difference of temperature. FEOM EXPEEIMENTS MADE, IT IS POUND THAT THE SPECIFIC GRAVITY INDICATED BY 496 THE LACTOMETER SHOULD BE AS FOLLOWS : For Cows' Milk . . . . 26 to 38 Cows' do. (grass-fed) before being Creamed . . . 32 Cows' milk (grass-fed) the cream being taken off . 38 Woman's ditto . . . 28' 38 Ass's ditto , 30 34 For Goat's do. (house-fed) . .30 34 Milk of Ewes (grass-fed) before being creamed . . 36 ,, Ditto ditto, the cream being removed . . . . 46 Mare's milk . . . . 36 DR. HASSALL. 497 Sheffer's Hydrometers, one from '700 to 1000, the other from 1000 to T900 with solution tube, per pair (figs. 453 and 453*) . . . . 15 498 Cartier's Hydrometer, chiefly used in France for testing fluids lighter than water. It is a modification of Baume's spirit hydrometer, the same point being taken as the zero of the scales. The space which in Baume's scale is divided into 32, is in Cartier's divided into 30 . . . .060 499 Gay Lussac's Alcohometer or Hydrometer, for testingjthe strength of spirits mostly used in France. The scale is divided into 100 parts, the lowest division, marked at the bottom of the scale, denotes the specific gravity of pure water at a temperature of 15 Cent, or 59 Fahr. The highest division at the top of the scale indicates the specific gravity of absolute alcohol of sp. gr. '796 at the same temperature. The intermediate degrees indicate the number of volumes of such alcohol in 100 volumes of the spirit tried 060 500 Baumes' Saccharometer floats at 30 in a solution the Specific Gravity of which is 1'26 this is the density of Simple Syrup when boiling ; hence if the Saccharometer floats at 30 in a solution of Sugar, when boiling it is inferred that such solution will be exactly saturated when cold. The scale is sometimes graduated to indicate the proportion of Sugar in the solution under examination. 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 187 Q O FIG. 492. PAGE 168. FIG. 514. FIG. 517. FIG. 513. 501 Fahrenheit's Hydrometer has two glass bulbs blown on a tube similar to the ordinary hydrometer, the upper bulb being the larger. The top of the stem is terminated by a small cup or dish. The lower bulb is weighted with mercury sufficient to cause the partial immersion of the instrument when placed in water without any weights being placed in this cup. In the middle of the stem is a mark, to which point the hydrometer is adjusted in water by placing weights in the cup. Its use is similar to that of Nicholson's Gravimeter. 10 6 502 Densimeter, a modification of Fahrenheit's instrument, chiefly used in France 12 6 503 Richter's and TraUe's Hydrometer, with Thermometer . . . 15 6 504 Normal Alcoholometer, Tralle's, used in Prussia and the United States, has a scale figured from to 100, each degree repre- senting one per cent, by volume of Alcohol, Specific Gravity 07939 in any mixture of Alcohol and Water at 60 degrees temper- ature Fahrenheit 14 505 Wooley's Hydrometer. This instrument has 2 scales, viz., Government Proof and Specific Gravity 066 506 A set of five Standard* Glass Hydrometers. Government Proof Scale, forty under Proof to sixty over Proof, with a very accurate Thermometer in a Mahogany Box, with Book of Tables as used with the metal Hydrometer 400 507 Hermbstadt's Hydrometer and Saccharometer, having two Scales, one showing Specific Gravity, I'OOO to T321 and percentage of Sugar to 67 066 188 NEGRETTI AND ZAMBEA, HOLBOEN VIADUCT. E.G., FIG. 515. . FIG. 515*. Each Each s. d s. d. 508 Volumeter (Gay Lussac's), for liquids lighter or heavier than water 066 509 Densimetre (Gay Lussac's), for liquids lighter or heavier than water, in two spindles simple form ... 086 510 Ditto (Rousseau), for ditto ditto ditto . 086 511 Photographic Hydrometer, or Argentometer, showing grains per ounce of nitrate of silver in solution . 036 512 Hydrometer Test Glasses, or Jars, on foot (figs. 512 and 515*) 2s. 3 6 056 513 Salinometer Glass, for ascertaining the density of salt water in steam-boilers, to prevent incrustation (fig 471.) 056 514 Ditto ditto, Gilt Metal, in tin case (fig. 466) 18 515 Ditto Ditto, Gilt Metal or German Silver in Box, fig. 467 1 1 516 Ditto with Thermometer in Mahogany box ... 1 12 517 Salinometer Thermometer (fig. 469) . 066 518 Ditto, Testing Pot, Stout Copper, with division for Thermometer. 086 The Salinometer used for testing the density of water in Marine Steam Boilers has a scale with five principal divisions marked upon it, the first division on the top of the stem is marked 0, representing pure water, the others marked 3 ' 2 | 2 3 $ and 3 4 5 signify that when the Salinometer floats at any of these divisions, that the water contains 1, 2, 3, or 4 parts of saline or solid matter in 32 of water. Between 5 2 5 and 3 3 5 is engraved the word Blow, indicating that when the Boiler Water has reached that density, a portion of it should be blown out of the boiler and replaced with fresh water. The temperature at which the water is to be tested is 200 Fahr. At the 3 2 5 the word " Limit " is marked, when, at that indication, it becomes dangerous to work it beyond that strength or density. Thus, this Instrument purports to indicate the precise time at which Marine Steam Boilers should be blown off, not only to prevent waste by blowing off too frequently, but to avoid the possibility of the Boiler being injured by the deposition or incrustation of the salt, which is a bad conductor of heat, and frequently the cause of the Boiler being burst. The engineer, by merely looking ab the scale of the Salinometer as it floats in the water, can at once ascertain the saline density of the water with the greatest accuracy. 45, COENH1LL, E.G., AND 122, BEGENT STREET, W., LONDON. 189 TO USE THE SALINOMETER. 5 1 9 Fill the Assay Jar from the Boiler, suspend the Thermometer in the side partition of it, and immerse the Ball in the water ; then at whatever division on the stem it rests level with the snrface, will be the degrees of saline matter contained in the water at the temperature of 200 ; but if the heat of the water varies below that degree, the following scale of temperature will be the blowing-off point : TEMPERATUKE. 200 -^1 180 |f } at surface for Blowing-ofC point. 160 sf I Under the circumstances at which fresh water boils at 212, sea water boils at 213'2. The boiling temperature is raised by the chemical solution of any substance in the water, increasing with amount of matter dissolved. For this reason, marine engineers use a Thermometer to determine the amount of salts held in solution by the water in the boilers of sea- going steamers. Common sea water contains about -| s of its volume of salt and other earthy matters. As evaporation proceeds, the solution becomes proportionally stronger, and more heat is required to produce steam. The following table by Messrs. Main and Brown shows the relation between the boiling point under the mean pressure of the atmosphere, or 30 inches of mercury, and the proportion of matter dissolved in the water. When the salts in solution amount to || the water is saturated. It has also been ascertained that, when a solution of -\ is attained, incrustation of the sub- stances commences on the boiler. Hence it is a rule with engineers to expel some of tlie saturated water, when the thermometer indicates a temperature of 216 F, and replace it with fresh water, in order to prevent incrustation and injury to the boiler. 520 The Boiling point of Saturated Solution of Salt varies from 218 degrees to 226 Fahr. Proportion of Salt in 400 parts of water . . Boiling point 212 -53 213-2 214-4 215-5 3V * 216-6 217-9 219-0 220-2 221-4 222-5 223-7 224-9 if . . 226-0 For further information on this subject, see Temperature Thermometer in conjunction with pressure gauges, page 151. 521 Salinometer, or Salt Water Guage, (How's Patent), constructed of strong Gun Metal and Brass, for attaching to the Boilers of Marine Steam Ships, to ascertain at any moment the specific gravity of the water contained in the Boiler. Complete, with Metal Salinometer, Thermometer, and Lamp ; best finished Gun Metal Tap Unions and Yalves. 880 522 Salinometer, Saunders 880 523 Ditto, Gambles . .880 190 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., 624 Spirit Gravity Beads are small light hollow spheres made of white or coloured glass about half-an-inch in diameter, with a stem or tail of about a quarter of an inch in length. The use of this stem is for adjusting each bead to a certain degree of Specific Gravity, or to a given degree of Sike's Hydrometer Scale. The degrees are engraved upon each Bead, thus forming them into rough Hydrometers for ascertaining the Gravity of various Fluids of Spirits. When the Bead floats about half-way in any sample of liquid to be tested, the density or specific gravity of such liquid is indicated by the figures or numbers engraved upon the bubble. 525 Salt Water Beads, or bubbles, for Aquaria . . . in pairs 020 The average Specific Gravity of Sea Water is T026 to 1/028. Gravity Beads for Aquaria are made of different coloured glass, one adjusted to float upon the surface of the water, and the other to remain at the bottom of the tank when the water is of suitable density for the healthy growth of fish or plants. Each. s. d. 526 Specific Gravity Beads, (or Spirit Bubbles, Glasgow Beads), for showing the strength of spirits, set of twelve, in japanned tin box .... 066 527 Ditto, ditto . . . . set of eighteen 10 6 528 Specific Gravity Beads, for heavy and! light fluids, such as aether, alcohol, ammonia, oil, naphtha, acids, each . 010 529 Specific Gravity Bottles, 1,000 grains' capacity, in tin case with counterpoise weight. (See also Chemical Section.) 10 6 530 Ditto ditto 500 grains 086 531 Ditto ditto 250 grains 066 532 Nicholson's Gravimeter, for ascertaining the specific gravity of metals or other solid substances, Japanned tin (fig. 532) with Metal Case ... 10 533 Nicholson's Gravimeter, larger size, accurately made in BRASS, fitted in case, with weights ranging from l-10th to 1,000 grains (fig. 533) .... 330 Nicholson's Hydrometer or Gravimeter is a modification of Fahrenheit's instrument, and is made either of very light tin japanned, or gilt brass ; its form will be seen in fig. 532. A mark is made on the stem supporting the cup to which the instrument is adjusted by weight to float in water. The weight of the loaded instrument when sunk to this point is the weight of the volume of liquid displaced by it. It gives, therefore, the relative weights of equal volumes of the liquids into which it is placed. The Gravimeter is usually made to displace 3,000 or 4,000 grains of water, and is sensible to the tenth of a grain in this quantity. With this instrument the 'specific gravity of ...,., solids may also be ascertained. By placing the solid to be tested IG * ifilllpl in the cup on the top of the stem and adjusting the additional weights required to sink the Hydrometer, the weight of such solid body in air is found. Then by placing the solid in the lower cup immersed in the water, and again adjusting the weights as before, the weight of the solid in water is ascertained; F 533 ^ and f rom tliese two resuits tne specific gravity is calculated. 45, CORNHILL, B.C., AND 122, REGENT STBEET, W., LONDON. 191 DIRECTIONS FOR USING NICHOLSON'S GRAVIMETER. 534 To find the specific gravity of a mineral or other solid, place weights in the upper cup sufficient to sink the Hydrometer to the mark on the stem when the Hydrometer is floated in distilled water, and call this weight A. Now take a piece of mineral of less weight than A ; place this in the upper cup, and add weights until the Hydrometer sinks to the same mark as before. Call the weights added B. Remove the solid from the upper cup to the lower, allowing the weights to remain in the upper cup. Add weights until the Hydrometer sinks to the mark on the stem, and call the additional weights C. Subtract B from A, and divide the remainder by C, and the quotient is the specific gravity. Thus, suppose the specific gravity of a specimen of fluor-spar is required. First, on trial, we find that 460 grains placed in the upper cup will sink the Hydrometer to the mark on the stem when floated in distilled water consequently, A is equal to 460 grains ; and that when the fluor-spar is placed in the upper cup, 92 grains must be added to sink the Hydrometer to the same level as before then B is equal to 92 grains. Now, on removing the fluor-spar to the lower cup, 115 grains must be added to the 92 grains still remaining in the upper cup to sink the Hydrometer to the same mark as before ; therefore C is equal to 115 grains. Then 460 92 115)368(3-2 345 230 230 Censequently, 3-2 is the specific gravity required. In our Chemical Section will be found and described Balances arranged to exhibit the same facts with extreme precision. URINOMETERS. 535 536 537 538 539 540 541 FIG. 539. FIG. 538. Urinometer, for ascertaining the Specific Gravity of Urine, of two forms, figs. 444 and 444* Ditto, ditto, in round leather pull-off case, with graduated test glass Ditto ditto, in hingedj.eatb.er case Ditto ditto, with test glass and thermometer, Ditto, ditto, in hinged Leather case, fitted up with thermometer, spirit lamp, acid bottle, test tubes, dropping tube, graduated jar, test papers, &c. (fig. 538) Urinometer, larger case, and more complete, with extra stoppered and cut test bottles and evaporating dishes, tube holder, &c. (fig. 539) 2 Metal Urinometer, Gilt or Plated, in pull-off case . Urinometer Test Papers, various per book s. a. 2 15 1 10 192 KEGBETTI AND ZAHBRA, IIOLBORN VIADUCT, B.C., FIG. 445. FIG. 444. FIG. 444*. FIG. 449. 544 The Urinometer originally suggested by Dr. Prout for ascertaining the density of urine has a scale divided into 60 degrees, the zero being the point at which the instrument floats in distilled water at a temperature of 60 Fahrenheit. The numbers on the scale added to 1,000 (the assumed specific gravity of water) give the specific gravities at the respective points. If the number cut by the sur- face of the fluid under test be 30, it indicates a specific gravity of T030. On the reverse side of this scale will be found the letter W at the top, on the same line as the indicating water. Lower down the scale is a space marked H, signifying healthy standard, which ranges from 10 to 20 of the scale. The space from 30 to 60 is marked diabetes, the urine of diabetic patients generally ranging between these points. See figs. 444 and 444*. 545 Dr. Lionel Beale's Clinical Cabinet arranged as a companion to Dr. Beale's work, The Microscope in its Application to Urinary Analysis. &c., &c. CONTENTS : Urinometer in sheath, 2 oz. graduated measure, glass pipette, stir- ring rod, test tubes, watch glasses, glass slips, and thin glass covers, glass spirit lamp, test tubes, holder, test papers, 8 improved capped dropping bottles (fig. 489) in ebonite rack, for containing the following re-agents : acetic acid, nitric acid, ammonia, potash, nitrate of barytes, nitrate of silver, oxalate of ammonia, &c. (fig. 445) .330 546 Urea Tubes divided to lOOths of a cubic inch 547 Improved Dropping Bottles, fig. 447 547* Dropping Tubes or Pippettes Glass . .076 .016 6d., 8d. 1 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 193 FIG. 551. FIG. 550. FIG. 552. FIG. 557. 548 Alcoholometer, Field's Patent, for ascertaining the original gravity of every description of ale, stout, or porter, at any period after fermentation. This apparatus is useful for testing comparatively various samples of beer, returned beer, and also beer for export. Price, complete in mahogany box, with directions for use, and correction tables of variation . 600 549 Wine or Spirit Analyser, Long's Patent, for ascertaining the quantity of alcohol in wines, cordials, &c., in accordance with Treasury Order of July 12, 1853, fixing the maximum of spirit in wine at 33 per cent. 4 10 Graduated Glass Measure Standard for use with above . . 036 550 Distilling Apparatus ; or, Phillips' Revenue Standard Still, for ascertaining the original gravity of Beer after fermentation, &c.; of strong brazed copper, with two Trial Jars and Thermometer, Pipette or Dropping Tube, &c. (fig. 550) 550 This apparatus is also used for the Alcoholic Wine Test by the Board of Customs for estimating the amount of Alcohol contained in Wines and Liqueurs. Gas Burner, improved for above (fig. 551) 12 6 Gilt Metal Hydrometer, pocket size for use with above apparatus, in neat case (fig. 552) 16 Gilt Metal Saccharometer, pocket size for ditto in case . . 16 Glass Flasks for Still, with metal screw fittings . . . . 046 551 552 553 554 555 Sikes' Hydrometers, for use in connection with the above, see pages 178, 179. o 194 NEGRETTI AND ZAMBEA, HOLBOEN VIADUCT, E.G. METHOD OF USING THE DISTILLING APPARATUS. 556 Attach the water supply, which may be a Cistern or Cask placed four feet above the Condenser, the connection being by Flexible Tube from the Tap of the Cistern ; the outflow of water is to be conducted into a pail, the quantity used being regulated by the Cock in the Cistern ; and the water having been found to flow through the Condenser in a con- tinuous stream, the Gas Lamp should be connected also by means of Flexible Tube, with a Gas Pipe, and lighted on the top of the Gauze. Where Gas is not obtainable, a large Spirit Lamp can be used. To Test a Sample of Wine. Fill the Measure Flask with Wine to the highest mark, adjusting the exact quantity by using the Pipette ; pour the measured Wine into the Still Flask, rinsing out the Measure with a few drops of water which must be added to the Wine ; the measure being quite clean, is placed upon the bracket, and adjusted to receive the Distilled Wine Spirit; the Still Flask is then to be screwed tightly to the condenser, interposing an Indiarubber Washer between the Flask and the metal shoulder of the Still Pipe ; put the Lamp under the Still Flask, at first moderately burning, afterwards increase the flame ; in a few minutes the Wine will boil, and the vaporised Spirit will begin to con- dense, falling into the Measure. Repeated experiments have proved that with weak Wine, such as contain under 26 per cent, of Proof Spirit, it is only necessary to distil over one- half the bulk ; but stronger Wines, containing much extractive matter, require the operation to be continued until two-thirds are distilled ; the Standard Measure is therefore graduated at two-thirds as well as one-half. When the required point on the Measure is obtained, the original measure of the Wine (up to the highest mark) is to be made up with Water, then poured into the Trial Glass and stirred well, so that the Spirit and Water may be perfectly mixed : with the Thermometer the temperature should be observed, the strength being taken by Sikes' Hydrometer according to the usual tables. To insure extreme accuracy, it is necessary that the temperatures of the Wine before distillation, and the Spirit and Water before taking the strength by the Hydrometer, should be the same, that the two bulks may be identical. Accurate Balances and Weights, Specific Gravity Bottles, Test Jars, Graduated Measuring Glasses, &c., &c., for use with the Distilling Apparatus. See sections " Thermometers," " Hydrometers," and " Chemical Apparatus." 557 Negretti and Zambia's Patent Strengthened Glass Hydrometer, fig. 557 Of all glass instruments required by the exigencies of Science, the Glass Hydro- meter is the most delicate and fragile. Very many of these instruments are broken in carriage, and very recently the Government of India requiring a large number of Hydrometers for fiscal purposes, applied to Messrs. Negretti and Zambra for assistance in procuring an Hydrometer which could be safely sent to the interior of India. Messrs. Negretti and Zamba submitted some instruments, which so far fulfilled the conditions required, that 20,000 of Messrs. Negretti and Zambra's Patent Hydrometers were ordered and supplied. The novelty consists in insert- ing an inner tube down the stem, and reaching to the bottom, and there being fastened securely to the neck of the lower bulb ; it will be seen that by these means the weight of the instrument is supported from the bottom, and not at the juncture of the stem with the large bulb, where usually the breakage of the old form of Glass Hydrometers 'took place. Any form of Hydrometer described in the preceding pages can be constructed with Negretti and Zambra's improvement to order at a slightly increased expense. 45, COENHILL, E.G., AND 122, REGENT STEEET, W., LONDON. 195 558 Comparative Scales (Baker's) compiled from tables of eminent authorities, for the use of Chemists, Distillers, Brewers, Dyers, Bleachers, Paper makers, British Wine makers, Confectioners, &c., &c. It Comprises Specific Gravity Scale, TwaddeH'Sj'Baume's, Cartier's, Gray Lussac's, Saccharometer scale of Ibs. weight per barrel, Extract per barrel, and the Govern- ment Proof Spirit scale. Several percentage scales for Spirits, Acids, Chlorine, Ammonia, Solutions of Potash, Soda, and four comparative Thermometer Scales; viz., De Lisle, Centigrade or Celsius, Fahrenheit, and Reaumur, in all 34 scales, containing a vast amount of most valuable and useful information. Price 2s. each. Recent Acts of Parliament in connection with the adulterations of food, drugs, &c., &c., will often necessitate strict investigation; in such matters, therefore, Messrs. Negretti and Zambra cannot too strongly impress upon the minds of their customers the great importance of accuracy in all apparatus used for analysing or testing the purity or strength of the articles under examination. For such purposes, N. & Z., from their great experience in this special branch of their trade, can confidently recommend their instruments. The various Areometers, &c., &c., used on the Continent to ascertain the density of Liquids, made to order. GAUGING INSTRUMENTS, RULES, Ac. See Scales and Rules. Specific Gravity of fluid Mercury. The density of this Metal at 39-2 F., is 13-588, according to Kupffer. Hence its Specific Gravity near the point of congelation will be 13-694. MESSES PLAYFAIE AND JOULE. The Specific Gravity of solid (frozen) Mercury is stated by Kupffer and Cavallo to be about 14-0. According to Dufour, the Specific Gravity of Ice is 0-9178 ; Bunsen states it at O91674. " Sea Water freezes at 2'5 to C. ; the ice which forms is quite pure, and a saturated solution remains. If water contains Alcohol, precisely analogous phenomena are observed ; the ice formed is pure, and all the Alcohol is contained in the residue." GANOT. " M. Despretz by the cold produced with a mixture of liquid Protoxide of Nitrogen, Solid Carbonic Acid, and jEther has reduced Alcohol to such a consistence, that the vessel containing it could be inverted without losing the liquid." Lowest artificial cold produced by Chemical Combination, 187 below Zero F. A. S. TAYLOE. Ditto ditto 140 C. GANOT. Mercury freezes, 37'9 Fah. Kew. Carbonic Acid Gas Solid at 148 below 0, F. We are informed that lower temperatures have been recently produced ly Chemical action. o2 196 KEGBETTI AND ZAMBRA, HOLBOEN VIADUCT, B.C. FIG. 562. FIG. 563. 29 28- 97- 26- 25- 24- 23- 22 */ 20 19 18 17 16 15- H IS )2 JO 6^ l? 3 4 r ife 3 -14 -13 -1Z -11 HO I-T -2 o FIG. 559. FIG. 564. Each s. 2 2 2 10 MERCURIAL VACUUM GAUGES. 559 Vacuum Gauge, in Mahogany or Oak frame, form as fig. 459 . 560 Ditto ditto in Plain Brass frame . 561 Marine Vacuum Gauge, in Oak frame, iron cistern, stout glass tube, gun metal unions, and OPAL GLASS SCALES, divided to 1- 100th of an inch . 440 562 Vacuum Gauge, The tube and scale are enclosed in stout Glass cylinder and Brass frame, with stop-cock and union (fig. 562) . 1 10 563 Sugar Pan Vacuum Gauge, as above, in Brass case, with Hinged Door, ground plug, fitting with Stop-Cock, &c. (fig. 563) . . 2 10 564 Vacuum Gauge, to show 30 inches, in handsome Mahogany case, with plate glass front, adjusting glass cistern, Gun Metal Tap, &c., suited for First-class Engine Rooms (fig. 564) . . . .550 For Circular Vacuum Gauges, see Bourdon's Gauges, pages 206 to 209. 45, COBNHILL, E.G., AND 122, REGENT STEMET, W., LONDON. 197 GUN" METAL WATER GAUGES. 565 On an improved principle, with Ebony handle spanners, complete mth glass tube and vulcanised rubber rings : fig. 565. f -in. 30s, -in. 35s. |-in. 40s. f-in. 42s. GAUGE TUBES. 566 Gauge Tube, for Steam Boilers, &c., of stout annealed glass, manufactured expressly for this purpose. Various lengths and diameters cut to order, average Id. per inch GAUGE TUBES of the best quality : SIZES. 12 10 12 H 10 12 14 PER. DOZ. SIZES S. d. . 6 lObyf . 7 12 | . 7 13 * . 7 6 14 f . 8 15 f . 8 6 16 ,, 1 . 9 12 f . 10 PER DOZ. SIZES 8. d. . 8 13 by f . 9 14 I . 9 6 15 I . 10 16 I . 10 6 18 I . 11 16 1 . 11 6 18 1 PER DOZ. 8. d. . 11 . 12 . 12 . 16 . 17 . 20 . 22 Estimates given for large quantities India Rubber Washers for Packing Water Gauges supplied to order. GAS PRESSURE GAUGES. FIG. 572. FIG. 568. FIG. 570. 567 568 569 570 571 572 Each. B. d. Gas Pressure Gauge, with 6 -inch glass syphon, Wood Scale divided to inches and tenths, and brass mountings Ditto ditto, with Stopcock 10 Ditto, with Ivory Scale and Stopcock (fig. 568), best finish . 14 Gas Pressure Gauge, large size (fig. 570), with Stopcock and Union 1 5 Ditto, of superior finish, as supplied to the Metropolitan Board of Works, in Brass Mountings, with stopcock , . . 1 10 Gas Inspector's Gauge, with fittings complete, in leather pocket case (fig. 572) , , . . -220 198 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., ini FIG. 565. FIG, 575. FIG 573. Each s. d. 573 Steam Engine Indicator, in gun metal, for ascertaining the amount of power exerted during any part of the stroke, Low Pressure (fig. 573) 550 574 Ditto ditto . . . . High Pressure 660 575 Richard's Indicator with one Spring (fitted with Darke's Patent Detent and Cord Adjuster) fig. 575 8 10 576 Extra Springs, ten varying scales each 10 577 Paper Cylinder Spring 016 578 Arrangement for Oscillating Engines 10 579 Metallic Paper per packet 040 580 Treatise on Indicator New Edition 090 581 Extra Stop Cock 080 582 A 3-way Cock for taking diagrams from top and bottom of cylinders without shifting the Indicator made to order. Connecting Pipes made to order. Elbow for attaching the Indicator to Horizontal Engines made to order. 583 Reducing Gears, for reducing the stroke of the Engine down to that of the Indicator. Made to order. 584 Small size with Pulleys for strokes varying from 4 ft. 6 in. down to 1 ft, 6 in., price, 4 17s. 6d., can be attached direct to the Indicator. Larger size for strokes from 6 ft. down to 1 ft. 6 in., 5 17s. 6d. These instruments are packed in mahogany cases with their necessary attachments. 585 Old Indicators (Richard's), fitted with Detent at . . . . 1 10 586 Patent Cord Adjusters . . . .... . .056 45, COBNHILL, E.C., AND 122, BEGENT STREET, W., LONDON. 199 FlG. 578. FIG. 587*. 587 The Patent " Concentric " Steam Engine Indicator, (figs. 587 & 587*) Negretti and Zambra call the attention of Engineers to great improvements in the new " Con- centric " Indicator, which reduces the vibration of the instrument to a minimum. The paper drum is arranged in such a manner that it revolves concentrically with the piston cylinder. The pull action is direct upon the coupling which connects it to the cylinder of the engine. This arrangement causes less vibration to the instrument than if the drum were fixed on an arm, as in the ordinary form of Richard's Steam Engine Indicator. A small instrument is made especially for high speeds, to which this indicator is particularly adapted. 200 NEGRETTI AND ZAMBRA, HOLBOEN VIADUCT, B.C., DIRECTIONS FOK USING THE INDICATOR. 588 Before working, a sheet of metallic paper is placed around the drum, and fastened to it by means of the two clips, The cord is then attached to the most convenient part of the piston rod or other part of the engine working in unison with it. The Indicator is fastened to the cylinder of the engine by means of the cock and coupling. The small leading wheels may be turned in any direction required. To change the spring, unscrew the nut at top, through which the piston rod (of Indicator) works, and by lifting the arm which supports the parallel motion, the piston rod will come out. The pencil can be removed from or pressed against the paper by lifting or pressing the stud connected to the slotted bar which the pencil works. It will be necessary, in sending orders, to specify particularly the number of springs required and the pressure they will have to indicate. All the springs will fit every instrument, and they can be readily changed by any one. The springs are made to ten scales, as follows : No. 1 i-in. on the scale represents 1-lb. No. 5 a . . 15 ,+ 60 pressure on the square in., indicates > 6 ^ . 15 , + 80 from . . . 15 to + 10 7 sSr . Atmosphere , + 100 2 ^ . . . 15 + 22 8 -JL . , + 125 3 To 15 + 35 9 1 + 150 : "SO 15 + 47 10 A . . . . + 175 each s. 7 10 70 10 01 10 04 09 08 d. 6 PRICES. Indicator with one spring, &c., in box, fig. 587 Ditto ditto, Smaller size . . Extra Springs (with scales) . . Paper Cylinder Spring ...... Arrangement for Oscillating Engines . . . Metallic Paper ..... per packet Treatise on Indicator . . . New Edition Extra Stop Cock ...... . Three-way Cocks for taking diagrams from top and bottom of Cylinder without shifting the Indicator Elbow, for attaching the Indicator to horizontal Engines ........ Connecting Pipes made to order. Spring No 1 has been specially adapted to indicate the vacuum on a large scale in engines or pumps which work at high pressures. The springs showing pressures above 80-lbs. will be made to indicate the vacuum also when so ordered, and springs will be made also to any other scale desired. COUNTING, TALLYING, MEASURING, AND REGISTERING MACHINES, OR ENGINE COUNTERS. 589 Improved Engine Counter, for counting Oscillating motion, Reciprocating 200 066 Strokes, or Revolutions in machines. 4 figures, counts up to 10,000 5 100,000 6 1,000,000 7 10,000,000 s. 2 16 33 3 10 4 10 590 Harding's Patent Speed Indicator. This instrument has been designed for showing without counting or the use of a watch, by the position of an index on a dial, the actual rate of speed at which any Machine or Engine is at any moment revolving. The Speed Indicator enables the Engineer to see at a glance the variation in the rate of speed at which his machinery is running and detect causes of irregularity and run his engine at normal speed, Price, 5 10 45, CORNIIILL, B.C., AND 122, REGENT STREET, W., LONDON. ^ 201 FIG. A. FIG. c. HARDING PATENT CIRCULAR DIAL ENGINE COUNTER. 591 The ease with which the record of these Counters can at any time be read off is a great advantage which they possess over all dial counters (such as those on water and gas meters), in the difficult reading of which important errors are often made. Other advantages of these Counters are, great simplicity of parts and solidity of construction, in consequence of which it is almost impossible for the apparatus to get out of order. It consists in an ingenious combination of wheels and pinions. Each number wheel carries on the right edge of its rim twenty teeth, and on the left edge only two. The pinions are provided with eight unequal teeth, four being as broad and four half as broad as the pinion. Thus, as each number wheel completes its revo- lution, it moves the next one on one-tenth, and all the wheels are safely locked, except at the moment when they are being moved forward by their pinions. Some idea of the perfection of this arrangement may be gathered from the fact that the Pocket Counter or Speedometer, of which the mechanism is a mere reduction of that of the large Counters, may be used at speeds over 5,000 per minute. PRICE LIST FOR CIRCULAR AND SQUARE ENGINE COUNTERS. No (A) Large Engine Counter, 7 figures, to count to ten millions, with s. a. rotary or reciprocating motion, and -arranged so as to readily set back to zero (fig. A) . . . . . . . . 5 10 Square Engine Counter, ten inches long, 5 figures 5 10 Ditto Ditto with superior Clock lever movement for use in Marine Engine rooms. The Patent Enamelled Number Wheels shew indelible black figures on a white ground specially useful in dark positions 11 11 No. (B) Small Machine Counters (with rotary action only), with 6 figures 2 10 Ditto ditto with 4 figures 330 No. (c) Pocket Counter or Speedometer (plated, and in handsome case), with 4 figures, and steel friction bits (fig. c) . . . 2 10 No. (D) Turnstile Counters, 5 figures 3 15 Harding's Improved Engine Counters to suit customers' special requirements made vp to order. Full details should be supplied as to what is desired. 202 NEGRETTI AND ZAMBEA, HOLBOEN VIADUCT, E.C., 592 Duckham's Patent Suspended and Self - Acting Weighing Machines and Dynamometers, adapted to the Standards of all nations. They are entirely self-acting, and indicate the weight of even the most ponderous goods, during the ordinary operation | of loading or unloading. They combine extreme simplicity and unlimited power I with general utility, accuracy, low price, and economy in I working. They are invaluable to MERCHANTS, SHIPPERS, DOCK AND RAILWAY COMPANIES, as a ready and costless means of ascertaining the weight of merchandise in transit ; to IRON- MASTERS, that they may ascertain the weight of material even Fm. 592. during the process of manufacture ; to CHAIN, WIRE, AND ROPE MANUFACTURERS AND PURCHASERS, thab the strength as well as the weight of such material may be proved ; to SHIP OWNERS, that the weight of cargo and stores may be checked by the simple operation of lifting the same on board ; to ENGINEERS, BOILER-MAKERS, HARD-WOOD MERCHANTS ; and in fact, to ALL and any who deal with goods by weight, or are interested in knowing the strength, of materials or machinery, that the goods may be weighed, and strains and strengths tested, by a process which is entirely free of expense. " The inventor provides an open-top cylinder, which is filled with water or oil, and fitted with a piston and pressure gauge. For the purpose of weighing goods the cylinder is slung from an ordinary crane hook. The goods are attached to the piston rod, and immediately these are lifted as in process of loading or unloading ships or wagons the weight is denoted on the dial. Nothing can be more simple." Mechanic's Magazine. PRESENT PRICES FOR PATENT SUSPENDED WEIGHING MACHINE. B. a. 12 cwt. to 3 tons capacity, 45 Ibs. weight 17 17 5 tons ditto 56 24 10 tons ditto 85 30 9 30 tons ditto 280 . . . . . 50 593 Hearson's Strophe-meter, or Revolution Indicator. This Instrument indi- cates, by means of a pointer on a marked dial, the number of revolutions per minute an Engine is, at the time, revolving. It is so designed that when Engines are subject to incessant momentary fluctations of speed, the needle points steadily at a number expressing the mean velocity. It will be found particularly useful for Locomotives (the dial being graduated in miles per hour), for Spinning Machinery, and for Ships. The Instrument is worked by means of a rope passing round a pulley on the shaft of the Engine, or in connection with a friction roller against a coupling of the shaft. For description of the Instrument see paper read at the Institute of Naval Architects, and published in the Transactions for 1874, and also article in No. 4 Annual of Royal School of Naval Architecture. PRESENT PRICES. s. d. Strophometer with 9-inch Dial 10 10 Leading Pulleys for ditto 036 Connecting Arrangements for ditto .... from 2 10 45, CORNHILL, E.G., AND 122, EEGENT STREET, W., LONDON. PYROMETERS. 594 Gauntlett's Pyrometer. This Pyro- meter is constructed of metal bars expanding in a different ratio upon the application of heat, by which can be ascertained tempera- tures above the range of the mercurial ther- mometer. Its form is that of a long tube, surmounted by a dial with an index or pointer to indicate to 300 for fluids, or to 1,009 for furnaces, ovens, &c. (fig. 594) .... 595 Chronometrical Pyrometer Thermo- meter (Gauntlett's), with 8-day time-piece to indicate to 300 or 1,009 . 596 Daniell's Pyrometer, for indicating high temperatures, such as the melting point of metals, temperature of furnaces, &c., by the expansion of a bar of Platinum enclosed in a black lead cylinder, and measured by an index arranged with a spring and lever, to show upon a divided arc very small changes . 597 Wedgwood's ditto, for the same purpose, by the expansion of a Cylinder of earthenware ...... Each 3 d. 440 8 10 550 550 598 Ferguson's ditto, for showing the differ- ence of expansion in metals, suited for the lecture table as an experimental instrument .550 599 Hydro Pyrometer, Captain O. Bystrom's (Swedish Artillery), for ascertaining the heat of furnaces, &c. A ball of platinum, or other metal, is arranged upon a metal rod in such a manner that it can be inserted into the furnace to be tested, and when heated equal to the FIG. 594. temperature of the furnace quickly withdrawn and dropped into a given quantity of water. By observing the temperature of the water before and after the above-mentioned procedure, the difference obtained will be th^ value or amount of heat of the furnace 1 15 This Pyrometer is the most simple and practically useful of any of the above at very high temperatures. Price for Thermometer, Copper Bolt and Wooden Water Vessel. Further details respecting Pyrometers will be given in our section on" Chemical Apparatus. 204 NEGBETTI AND ZAMBRA, HOLBOEN VIADUCT, E.G., SIEMENS' WATER PYROMETER. JFiyl, 600 The PYROMETER is shown in figs. 1 and 2 in margin (fig. 1 being a vertical, and fig. 2 a horizontal section), and consists of a copper vessel capable of holding rather more than a pint of water, and well protected against radiation by having its sides and bottom composed of a double casing, the inner com- partment of which is filled with felt. A mercury thermometer, b, is fixed in it, having, in addition to the ordinary scale, a small sliding scale c, graduated and figured with 50 degrees to 1 degree of the thermometer scale ; 6 solid copper cylinders are provided with the Pyrometer, each accurately adjusted in size, so that its total capacity for absorb- ing heat should be l-50th that of a pint of water. In using the Pyrometer, a pint (0*568 litre, or 34'66 cubic inches) of water is measured into the copper vessel, and the sliding pyrometer scale c is set with its zero at the temperature of the water as indicated by the mercury thermometer b ; a Copper Cylinder d is then put into the furnace or hot blast current the temperature of which it is wished to ascertain, and is allowed to become heated for a time varying from 2 to 10 minutes according to the intensity of the heat to be measured. It is then to be withdrawn and quickly dropped into the water in the copper vessel, where it raises the temperature of the water in the proportion of 1 for each 50 of the temperature of the copper. The rise of the temperature may then be read off at once on the pyrometer scale, and if to this is added the temperature of the water as indicated on the mercury thermometer before the experiment, the exact tem- perature required is obtained. For very high temperatures Platinum cylinders may be employed instead of Copper. Price of Siemens' Water Pyrometer, with Thermometer and six copper cylinders, complete 440 Water Pyrometer, with Thermometer and six wrought-iron cylinders, complete . . . . , . .400 45, CORNHILL E.G., AND 122 REGENT STREET, W., LONDON. 205 FIG. 602. SCHAFFER'S STEAM PRESSURE AND VACUUM GAUGES * Gauges of any Pressure not exceeding 300 Ibs. per square inch, SQQfeet of water, and Vacuum Gauges : Each 601 For Portable Engines, Brass Case. 4-inch with wire *. a. guard ' 1 15 602 No. 1. In Metal Case, with Brass Rim 6-inch dial 226 No. 2. In Brass Case . . . (fig. 602) 2 10 603 No. 3. In Metal Case, with Brass Rim 7 276 No. 4. In Brass Case .... 2 10 604 No. 1. Patent Steel Tube Metal Case, with Brass Rim, above 300 Ibs. up to 1,000 Ibs. . . 6-inch dial 2 15 605 No. 2. Ditto Brass Case, above 300 Ibs. up to 1,000 Ibs 6 330 606 12-Inch with Transparent Dial for Dark Engine Rooms, Metal Case, with Brass Rim 330 507 Combined Pressure and Vacuum Gauges, at a slight increase of these prices. 608 Hydraulic Gauge, above 1,000 Ibs. up to 10 tons, with Maximum Pointer and loose nuts for connecting 10-inch Dial 550 Ditto ditto .... 6-inch Dial 4 10 Ditto ditto to 4 Tons . ... 400 For each additional ton, 5s. extra. Maximum Finger applied to any gauge, 10s. extra. 609 Dynamometer, Schaffer's. The dial showing the weight is accurately divided, by applying dead weight. Two solid curved steel bars act as springs. Weight or strain applied has the tendency to straighten these springs, and the slightest motion of the same is multiplied and transferred by a suitable arrangement to a pointer which indicates the correct weight on the dial. Two strong rods outside the springs, moving loosely in their joints, act as safeguards in case the springs break. Price, up to 20 tons . . 25 * Schaffer't Gauges, Sfc., not kept in stock, but are supplied to order. 206 KEGRETTI AND ZAMBRA, HOLBORN VIADUCT, B.C. FIG. 4. FIG. 5. FIG. 2. FIG. 7. FIG. 8. FIG. 6. FIG. 1. FIG. 9. FIG. 3. E. BOURDON'S STEAM PRESSURE AND VACUUM GUAGES. 35, CORN11ILL, E.G., AND 122, EEGENT STREET, W., LONDON. 207 610 PRICES FOR E. BOURDON'S OWN-MAKE STEAM AND VACUUM GAUGES. E. BOURDON , TEADE U -, MAEK. Gauges not bearing above Trade Mark are not of M. Bourdon's Manufacture. Diameter of ,Dial. PEESSUEE GAUGES. Vacuum Figs. 3 and 7. Compound Gauges. Figs. 4 and 8. Number. With Eccentric Hand. Figs. 2 and 6. Number. With Centrai;Hand. Figs. 1 and 5. 10 inches. 7 6 5 4 3 5 inches. No. No. 3 No. 5 No. 8 No. 7 No. 6 Each. 2 18 1 16 1 14 180 150 140 No.O No. 4 No. 50 No. 8c No. 70 No. 60 Each. 300 200 1 18 1 10 170 150 Each. 320 220 1 18 1 10 1 7 150 Each. 3 13 260 240 1 14 1 12 1 10 Above Gauges in round cases of polished brass with Or without flange, graduated to all pressures up to 300 Ibs. per square inch, and fitted with gun-metal cocks and union complete. Gauges above 300 Ibs. per square inch are without cocks. No. 2, Fig. 9, Oblong Iron case (9x6 in.) with connecting screw joint, each, 160 Above prices are for all pressures up to 300 Ibs. per square inch. From 300 to 1,400 Ibs. pressure per square inch there will be an additional charge of Two Shillings for every 100 Ibs. above 300 Ibs. Cocks for 5 in., 7 in., and 10 in. Gauges, for pressure above 300 Ibs. per square inch, up to 1,400 Ibs. will be Twelve Shillings each. NEGRETTI & ZAMBRA, AGENTS, LONDON. 208 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., FIG. 14. FIG. 10. FIG. 11. E. BOURDON'S HYDRAULIC GAUGES. FIG. 12. FIG. 16. FIG. 13. FIG. 15. E. BOURDON'S STANDARD AND DUPLEX GAUGES. 611 FIG. 18. FIG. 17. E. BOURDON'S DOUBLE AND REGISTERING GAUGES. 45, COBNHILL, E.G., AND 122, EEGETNT STEEET, W., LONDON. 209 612 BOURDON'S HYDRAULIC GAUGES*. With Central Hands, divided from 300 Ibs. up to 5 tons per square inch. Diameter of Dials. With Connecting Screw Joint. Fig. 10. - With Maximum Pointer. Fig. 11. With Valve, Union, and Maximum Pointer. With Valve, Union, and Electrical Contact. Each. Each. Each. Each. 10 inch. 7 5 400 350 2 10 4 10 3 10 2 16 5 10 480 380 600 500 400 613 d. Cocks for above Gauges (if required) 30s. each, extra. BOURDON'S STANDARD AND DUPLEX GAUGES. Used by Inspecting Engineers for Testing Gauges and Boilers. Fig. 12. Pocket Standard Gauge, with open face, in polished brass case, engraved dial, graduated to 300 Ibs. per square inch, in morocco case and clamp screw each Fig. 13. Two Gauges as the preceding, but fixed on the same union and in a mahogany box . . . per pair Fig. 14 Pocket Standard Duplex Gauge, in polished brass case (5 inches diameter) engraved dial graduated to 300 Ibs. per square inch, in Leather case with clamp screw ........ each Fig. 15. Standard Duplex Gauge, with two concentric hands, polished brass case, graduated to 300 Ibs. per square inch, with gun-metal cock .... each Fig. 16. Standard Duplex Gauge, with independent hands, &c., as last DlAMKTER. 3 inches. 5 inches. 3 7 inches. 3 16 3 7 13 6 5 10 inches. 500 3 14 4 15 EXTRA CHARGES. Diameter of Gauge. Maximum or Minimum Pointer. Second Scale of Feet of Water or Atmospheres. For 3-way Cock Writing Name on Dial. Open Face Each. Each. Each. Each. Each. 10 inch. s. d. s. d. s. d. s. d. B. d. 7 10 5 2 1 10 6 ,, 7 5 2 1 10 5 7 5 2 1 8 4 5 3 2 1 8 3 5 3 2 1 8 5 3 2 1 8 614 615 Fig. 17. Bourdon's Registering Gauge, in japanned case, graduated to 100 Ibs. per square inch, with gun-metal Cock and Union, and 100 printed cards 7 15 Extra cards, (if required) per 100 080 Fig. 18. Bourdon's Double Gauge, to be set in Engine-rooms, and showing on the same dial (10 inches diameter), pressure of Steam in the Boiler, and the amount of Yacuum in the Condenser, Polished brass case, and two Cocks with Union . 600 * A Table of Hydraulic Pressure will be found in the Appendix. 210 NEGRETTI AND ZAMBRA, HOLBORN YIADUCT, B.C., FIG. 24. FIG. 20. FIG. 21. FIG. 19. FIG. 23. FIG. 22. 616 FITTINGS AND CONNECTIONS FOR BOURDON'S GAUGES. Fig. 19. Connecting Screw Joint Figs. 20 & 21. Gun Metal Cock Figs. 22 & 23. Three-way Cock for Standard Test Gauges Fig. 24. Iron Syphon, with Union .... Fig. 24. Copper Syphon, with Union each s. d. 1 6 040 060 040 046 Purchasers are desired to examine and compare M. Bourdon's Gauges. They will find the works to be constructed and finished like a watch, whilst the majority of imitations are put together ROUGH FROM THE CASTINGS, consequently liable to adhere and give erroneous indications. NEGRETTI & ZAMBRA, SOLE AGENTS FOR BOURDON'S GAUGES. GUN-METAL FITTINGS FOR MARINE, LOCOMOTIVE, AND OTHER STEAM ENGINES AND BOILERS. Gun-metal Steam and Water Taps of all sizes and shapes, Safety Valves, Steam Whistles, Gauge Taps, High Pressure Water and Steam Yalves, Gas Yalves, Boiler Fittings of all kinds, Feed Pumps and Valves, Wrought Iron Steam, Gas, and Water Tubes, Boiler Tabes, Hand Force Pumps, Fire Engine and Brewery fittings, Pump fittings, Caps and Screws of every form, Hydraulic Presses and Force Pumps, Hydraulic Rams of various sizes and construction, Turning Lathes and Tools, Portable Forges and Smiths' Tools, &c., &c., Fencing Wire, Railway Metal Bars, Tools and appliances of all kinds supplied to order by Negretti and Zambra, of the very best manufacture. Foreign Correspondents sending particulars of their requirements to Negretti and Zambra may rely upon thepersonal attention of the Firm in carrying out commissions entrusted to them in this special branch of their Shipping Business. At pages 95 to 110, will be found Anemometers for testing Yentilating or Furnace Shafts and Wind Pressure, Recording Anemometers, and Tide Gauges, &c. 45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. fVl- 211 FIG. 617. 617 Improved Combined Portable Steam Engine and Boiler. These Engines are fitted with governor, throttle valve, safety valve, feed pump, water and steam gauge, &c., &c., complete, ready for immediate use. Recommended for simplicity and economy ; well suited for Exportation. Consumption of fuel, 7 Ibs. of coal j per horse power, 1 cubic foot j per hour Boiler. Ditto ditto * Horse Power Cylinder. Diameter. 2 4-in. 4 5l-in. water, Stroke. 10-in. 10-in. 12-in. 14-in. Height. 5-ft. 0-in. Diameter. 2-ft. 4-in. 73 0* 5-ft. 6-in. 2-ft. 4-in. 85 0* 7-ft. 0-in. 2-ft. 4-in. 105 8-ft. 0-in. 2-ft. 8-in. 165 * 2 and 3, if not fitted with Governors, less 5. The fly-wheel shaft is made sufficiently long to admit of a drum being fixed on if required, which can be supplied (to any diameter ordered) along with the Engine, at an extra cost according to size. The above Engines occupy a very small space, and will be found admissible in places where no other form of engine and boiler could be fixed. They are con- structed in an exceedingly substantial and simple manner, every part being perfectly easy of access, and consequently can be readily understood and managed. The boilers are fitted up with strong welded tubes (varying in number according to the size of the boiler), intersecting the fire-box, and a mud hole is placed opposite each tube, for the purpose of cleaning them out. They are tested up to 200 Ibs. pressure to the square inch. The foundation plate answers the purpose of feed water tank, in which the water is heated before passing into the boiler ; and also of an ashpit. No brickwork or foundation is required. N. and Z. will forward special quotations to Foreign Correspondents for Steam and Gas Engines or other Machinery upon receiving details of the nature and amount of work to be performed. p 2 212 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., OPTICAL INSTEUMENTS. THE science of .Optics, which consists in the examination of the phenomena of light and vision, is one of the most important and most useful branches of physical science. By the aid of its appliances we are permitted to obtain a glimpse' of the immensity of the universe, and are enabled to reveal wonders of creation, of which but for this power granted to us we should be in perfect ignorance. By means of the Telescope we are made acquainted with the existence of spheres and worlds floating in boundless space, illustrating in the most sublime manner the perfect harmony that exists in the motions of the heavenly bodies. The Microscope affords an insight into the minute structure of animal and vegetable life, and discloses to the wondering spectator forms of life, the variety and beauty of which display in the most convincing manner the infinite power of the Great Creator. But of all the gifts which science has so freely lavished on humanity, and all tending to its benefit and improvement, perhaps there is none that can rank higher than the means afforded of assisting the natural vision, and of enabling us to correct in a most simple and perfect manner the irregularities of sight, which are conse- quent on alterations silently going on in the structure of that wonderful and deli- cately constructed organ, the Eye. The sight has in all time been justly accounted the greatest of blessings, and it deserves our strictest attention in order that the advantages of it may not be lost to us at an earlier period than is absolutely necessary from physical decay. Those beginning to require the aid of Spectacles are obliged, before distinct vision can be obtained, to hold the candle or to have the source of light between the eye and the book they read, in order to force the pupils of their eyes into a proper state of contraction, that they may see distinctly the characters before them. Now this is a state of things that should never occur, for if indulged in, and the eye be tampered with, it will eventually lead to great impairment of vision. The power of adjustment in the eyes varies exceedingly in different individuals and also at different periods in the life of each person ; being strongest in youth, and gradually diminishing with advancing years. From this circumstance it is easy to see the reason of the fatigue caused by the strain on the ciliary process of the eye in bringing it to a proper adjustment for objects at different distances, and an individual who has habitually to make an effort to adjust his eye to these variations of circumstances, should lose no time in applying to the Optician to obtain assistance from the use of glasses. From what we have said above, let it not be supposed that the indiscriminate use of Spectacles is recommended ; very far from it. We must, before resorting to Spectacles, ascertain the nature of the defect in the visual organs, and then have the amount, and only the exact amount of correction applied ; just in the same manner as with a telescope, we are obliged to draw out the eye-tube until a perfect image appears in the field of view, nothing more or less will suffice to this end. SPECTACLES. READING & EYE GLASSES, EYE PRESERVERS, &c., TO SUIT ALL AGES AND SIGHTS, GLAZED WITH THE FINEST BRAZILIAN PEBBLES OR BEST OPTICAL CROWN GLASS. NOTICE. N. & Z. devote especial care and attention to Oculists' Prescriptions, and no advance in prices is made unless extra deep lenses, Cylindrical lenses, or Prisms are ordered. N. & Z. cannot specify within the limits of this List the various combinations which influence the price, but if desired, the price may always be ascertained before ordering. The greatest care taken that the Pebble, or Glass Lenses, are correctly worked and polished, as well as carefully tested and suited to the sight of the Purchasers, and also that the Frames are formed to fit the face. 618 619 620 621 622 623 624 FIG. 61 FIG. 618*. Each. a. Each. s. d. Fine Blue or Bronzed Steel Spectacles, with straight or turn pin sides (figs. 618 and 618*) . . . . 10 6 12 Ditto ditto ditto, with Pebbles . 15s. 17 6 11 Fine Blue or Bronzed Steel Spectacles, with straight or turn pin sides (figs. 618 and 618*), extra large lenses . 12 6 15 Ditto ditto ditto, extra large Pebbles . 1 5 Blue Steel Spectacles, with straight sides (fig. 618) .026 03 Blue or Bronzed ditto ditto 056 07 Cataract Spectacles, in various mountings . 10s. 6d. 15 11 Cataract Spectacles are mostly made specially to meet the requirements of the Patient. 214 NEGRETTI AND ZAMBEA, HOLBOKN VIADUCT, B.C. FIG. 019. FIG. 619' Each. 621 622 623 624 s. 10 1 1 619 The Patent Pantoscopic Spectacles are so constructed as to enable the wearer to read or write with comfort. When the Spectacles are on the face, the position of the lenses is such that the light passes through them at right angles to their urfaces, and the upper part of the lenses being slightly straightened, enables the earer to converse with anyone, or see distant objects, without looking through he lenses or drawing the Spectacles down upon the face, Figs. 619 and 619*. N". & Z. strongly recommend this form of Spectacles. 620 Patent Pantoscopic Spectacles, in light blue steel, for E s? h 'a. ladies or gentlemen, with the best Periscopic Lenses Ditto ditto, with best Brazil Pebbles . . . 15 6 Ditto ditto, in Solid G-old, with best Brazil Pebbles 42s. 2 10 Ditto ditto, in Solid Silver, with ditto .110 Invisible Steel Spectacles, blue or bronzed, with straight sides. The lenses are grooved to receive the frame, which, being extremely light, is scarcely visible. These Spectacles are specially adapted for Concave lenses worn by short-sighted persons. Straight or turn pin sides 10s. 6d., 12s. 6d., 15s. Ditto ditto ditto, with Pebbles . . . 15s. 18 150 Invisible Steel Spectacles, with Curled sides to fit behind the ears (fig. 626) 10s. 6d. 12 6 0180 Ditto ditto ditto, with Pebbles . . . 15s. 18 150 625 626 627 628 Gold Spectacles, fitted with Pebbles, Light Frames : 10 Carat. 12 Carat. 15 Carat. 18 Carat. Single Sides 1 7s. 6d. 1 17s, 6d. 2 12s. 6d. 3 15s. Od' Turn Pin do. 1 11s. 6d. 2 4s. Od. 3 Os. Od. 4 5s. Od. Ditto ditto ditto, Strong Frames : Single Sides 1 Us. 6d. 2 8s. Od. 3 Os. Od. 4 4s. Od. Turn Pin do. 1 17s. 6d. 1 12s. 6d. 3 7s. 6d. 5 Os. Od. Ditto ditto ditto, Extra Stout Frames . Single sides 2 2s. Od. 2 15s. Od. 3 15s. Od. 5 Os. Od. Turn Pin do. 2 5s. Od. 3 3s. Od. 4 10s. Od. 5 15s. Od. 631 Either of the above Spectacles may be had with Patent Pantoscopic Frames without extra cost, as Fig. 619. 629 630 45, COfliniILL, E.G., AND 122, REGENT STREET, W., LONDON. 215 FIG. 626. 632 Invisible Gold Spectacles, with Curled Sides to fit behind the ears. The lenses grooved to receive the frame (as Fig. 626), 12 Carat, with glasses 1 to 2, with Pebbles, 2 to 2 10s. N. & Z. do not recommend a higher quality gold for these Spectacles, it being too soft for durability. 633 Sterling Silver Spectacles 12s. 6d. 15s. 1, and upwards, according to weight. 634 Ditto ditto, with Pebbles, 18s. 1 Is. 1 5s. Gold and Silver Spectacles are strongly recommended to persons residing in Tropical Climates, or at the Seaside, as they resist the action of moisture. 635 Gold Double Eye Glasses, (folding). The frames and the springs are of Gold throughout, and with shell placquets to those parts which touch the nose. Fitted with Pebbles. Light Frames : 10 Carat. 12 Carat. 15 Carat, 18 Carat. Figs. 640* & 640f 1 Is. Od. 1 10s. Od. 2 2s. Od. 2 10s. Od. Fig. 640 1 5s. Od. 1 15s. Od. 2 5s. Od. 3 Os. Od. Strong Frames : Figs. 640* & 640 115s. Od. 2 Os. Od. 2 10s. Od. 3 5s. Od. Fig. 640 2 Os. Od. 2 7s. 6d. 3 3s. Od. 4 Os. Od. Fig. 646 2 2s. Od. 2 10s. Od. 3 5s. Od. 4 4s. Od. Extra Stout Frames : Figs. 640* & 640 2 5s. Od. 3 3s. Od. 3 15s. Od. 4 15s. Od. Fig. 644 2 15s. Od. 3 10s. Od. 4 4s. Od. 5 10s. Od. Fig. 646 3 3s. Od. 4 Os. Od. 5 Os. Od. 6 6s. Od. NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., FIG. 636. ^=s^ FIG. 636*. 636 Gold Double Eye Glasses (folding), with round or oval eyes, with Pebbles. (Figs. 636 and 636*). Strong Frames : 10 Carat. 12 Carat. 15 Carat. 18 Carat. 2 5s. Od. 2 15s. Od. 3 15s. Od. 4 15s. Od. Extra Strong Frames : 2 10s. Od. 3 3s. Od. 4 Os. Od. 5 10s. Od. 637 Ditto ditto ditto, with Spring and Catch, round or oval eyes, with Pebbles, (Figs. 636 and 644). Extra Strong Frames : 2 15s. Od. 3 10s. Od. 4 5s. Od. 5 15s. Od. 638 Ditto ditto ditto, with Rigid Bridge, folding, but used open and held in the hand. Round eyes only, with Pebbles (Fig. 636). Extra Stout Frames : 5 15s. Od. 4 4s. Od. 5 5s. Od. 6 6s. Od. FIG. 640. FIG. 640*. DOUBLE EYE GLASSES (Folding). VARIOUSLY-CONTRIVED SPRINGS TO SUIT DIFFERENT FORMS OF FACE. 639 640 Blue or Bronzed Steel Double Eye Glasses (Fig. 640*) .0 Best Nickel Plated Steel Ditto ditto (Figs. 640 and 640f) having Shell Placquets to those parts which touch the nose ..... . . . 5s. 6d. Each. s. d. 36 Each. s. d. 056 641 Ditto ditto ditto, with Pebbles . 12s. 6d. 15 10 1 1 45, GORNHILI, B.C., AND 122, BEGENT STREET, W., LONDON. 217 Each. Each. s. d. a. d. 642 Best Nickel Plated Steel (Figs. 640 and 640*), highly finished invisible frames, with Grooved lenses . . 10 6 12 6 643 Ditto ditto ditto with Pebbles . . 15s. 18 150 FIG. 650. FIG. 646. FIG. 644. 644 Tortoise-shell Double Eye Glasses [(Pig. 644) Round or Oval 7s. 6d. 10 6 645 Ditto ditto ditto, with Pebbles 646 Tortoise SheU Double Eye Glasses (Fig. 646), with Solid Steel Bridge ditto ditto 12s. 6d. 15 12s. 6d. 15 ditto, with Pebbles . . .110 ditto, with Solid Gold Bridge .150 ditto, with Pebbles . . . 1 10 ditto (Fig. 650), Bound or Oval . 7s 6d. 10 6 12 6 17 17 6 150 1 10 1 15 647 Ditto 648 Ditto 649 Ditto ditto 650 Ditto ditto Eyes . . . ' 7s 6d. 10 6 12 6 651 Vulcanite Double Eye Glasses (shape as Figs. 644 and 650) 2s. 6d. 3s. 6d. 4 6 056 652 Figs. 640, to 650 show recent improvements in Clip-Nose, (Pince-Nez) Spectacles, or Folders. The Cushions, or Placquets, on th'e inner edges of the Frame distribute the pressure over a large surface, causing the Folder to fit exceedingly firm on the face, and parallel to the eyes. These forms of Folders, known as Chinese, Japanese, American Extension, or Non-Pressure, are found to be the most comfortable in wear yet introduced. 218 NEGRETTI AND ZA.MBRA, HOLBORN YIADUCT, E.G., SINGLE EYE GLASSES. FIG. 653. FIG. 654. FIG. 657. 653 Gold Eye Glasses, single (fig. 653), fitted with Pebbles Each. Each. i for short sights, according to quality and substance s. d. s. d. 10s. 6d. 12 6 15 654 Gold Eye Glasses, single (fig. 654), fitted with Pebbles for long sights, ditto ditto, 21s., 30s. 200 2 10 655 Shell Rim Eye Glasses, (fig. 653), fitted with Convex or Concave glasses 2s. 2 6 036 656 Ditto ditto ditto, (fig. 654), fitted with Convex or Concave glasses 3s. 6d. 5 6 10 6 657 Rimless Eye Glasses, (fig. 657), Concave or Convex glass 010 658 Ditto ditto ditto, Meniscus Concave or Convex glass 016 026 GOLD HAND SPECTACLES (Folding). FIG. A. FIG. B. FIG. C. FIG. D. 659 Gold Hand Spectacles (folding), with Spring Joints, richly engraved, chased, enamelled or inlaid ; fitted with Pebbles for long or near sights 10 Carat, 4 4s.; 12 Carat, 5 5s., 5 10s., 6 6s.; 15 Carat, 6 6s., 6 10s., 7 7s. ; 18 Carat, 7 7s., 8 8s. and upwards (figs. A, B, C, D). 660 Silver Gilt ditto ditto ditto, fitted with Pebbles (figs. A, B, C, D) 40s., 45s. 2 10 330 661 Tortoise-shell or Mother-o'-Pearl Fronts, with Silver-gilt settings, fitted with Glasses . 18s., 21s., 25s. 1 10 200 45, CORNHILL, B.C., AND 122, EEGENT STREET, W., LONDON. 219 SPECTACLES AND EYE PROTECTORS FOR PRESERVING THE EYES FROM EXCESSIVE LIGHT, GLARE FROM SNOW, AND FROM WIND OR DUST. 662 663 664 665 666 667 FIG. 663. Each. s. d. Each. s. d. Best Solid Steel Frame Eye Protectors or Dust Spectacles, (fig. 662) with wire gauze or crape cups, and fitted with smoke or blue tinted flat glasses of the finest quality 10s. 6d. 15 Best Solid Steel Frame Eye Protectors, (fig. 663) with wire gauze cups, and fitted with large smoke or blue tinted Cup Shaped or Spherical Glasses of the finest quality 10s. 6d. 15 Best Steel Spectacles, (fig. 663), fitted with large smoke or blue tinted spherical -glasses of the finest quality 10s. 6d. 12 6 15 Ditto ditto, fitted with large smoke or blue tinted spherical glasses 7s. 6d. 10 6 12 6 110 110 FIG. 666. Best Steel Frame D Eye Preservers, (fig. 666) fitted with best smoke or blue tinted glasses, both in front and at the sides . 10s. 6d. 12 6 15 Ordinary Steel Frame D Eye Preservers, fitted with smoke or blue tinted glasses and with gauze side shades 5s. 6d. 6 6 076 220 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, B.C., FIG. 671. Each. s. d. 668 Best Steel Spectacles,"(fig. 618) with large smoke or blue tinted glasses of the finest quality . . . .076 10 6 669 Ordinary Steel ditto ditto fitted with smoke or blue tinted glasses .... 2s. 6d., 3s. 3 6 670 Goggle Spectacles, steel frame, with wire gauze cups, fitted with smoke or blue tinted glasses 3s. 6d., 5s. 6d. 066 671 Goggles, (fig. 671) to fit the head by means of an elastic band, fitted with smoke or blue tinted glasses from 1 Each. 8. 056 076 6 to 10 6 FIG. 683. FIG. 682. FIG. 689. 672 Best Nickel Plated Steel Folding Eye Glasses, (fig. 640*) with smoke or blue tinted Cup Shape or spherical glasses 10 6 673 Ditto ditto ditto, with smoke or blue tinted flat glasses .... ...0760 10 6 12 6 FIG. 675. FIG. 678. FIG. 676. 674 Steel Folding Eye Glasses, with smoke or blue tinted glasses 036 to 056 675 Shooting or Hunting Eye Glasses, steel mounted, with joints and screws for attaching to the Hat (fig. 675) .076 10 6 676 Ditto ditto ditto double (fig. 676) . 150 45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 221 FIG. 687. FIG. 686. FIG. 685. 678 French Pattern Spectacles, (fig. 678) with Single or & a s ' a. & B. ' d. Double sides, Gold " . . 1 10 to 3 3 679 Ditto ditto ditto Best Steel , 10 6 12 6 It is not generally known that vrhat are termed " Pebbles," as used in the construction of spectacle lenses, are cut from Rock Crystal. For such no better substance is obtainable when free from impurities, being much harder and brighter than glass. The difficulty, however, of obtaining " Pure Pebbles " is great, and not until much labour has been expended in cutting and polishing can any of the many defects be discovered which ultimately cause their rejection. It is in consequence of a large percentage of loss in the production of " Pebble Lenses " that the cost is so much greater than glass ; but it is only apparent, as the advantages of a higher polish, the non-liability to scratch or break, well compensate for the outlay. For the information of those who sometimes imagine their Spectacles no longer serviceable, Negretti & Zambra beg to say that a little expense will often, for all practical purposes, make them equal to new. The re-working of a pair of pebbles to a higher power, a new glass, soldering a broken frame, or a new spring to an eye glass, will frequently accomplish this end. These repairs are executed at moderate charges and returned by post in the shortest possible time from their receipt with instructions. Spectacles made to order of any shape or material, and fitted with lenses worked to any particular form. Pebbles re-worked and altered to suit the variation of sight. Spectacles or Eye Protectors, Gilt Plated or Nickeled, to prevent rust, at a slight advance on prices quoted. Spectacles suited to the Sight by sending an old Lens or piece of a broken one. 680 " SPECTACLES, WHEN TO WEAR AND HOW TO USE THEM : " addressed to those who value their sight. Published by NEGRETTI AND ZAMBRA. Price (post-free), 6d. 222 NEGRETTI AND ZAMBEA, HOLBORN VIADUCT, E.G., Each. Each. 681 Spectacle Cases, Leather, various forms and mountings 6d. 1 050 682 Oval and Bound Reading Glasses, in Horn cases (fig. 682) 2s. 6d. 5 076 683 Ditto ditto t Tortoise -shell case (fig. 683) . . 1 10 220 684 Ditto ditto in Pearl, with Silver mountings (fig. 682) 110 220 685 Cylindrical Lenses, in oblong Horn, Yulcanite, or Metal Frames (fig. 685) .... 15s. 6d. ; 17s. 6d. 1 1 150 686 Print Lenses, of various sizes, in turned Wood Frames, for viewing large Maps, Engravings, Photographs, &c. (fig. 686) ....... 21s. 1 11 220 687 Magnifying Lenses, mounted in German Silver, with Wood Handles, suited for examining Photographs, Engravings, &c. (fig. 687) 2s. 6d., 3s., 3s. 6d., 4s. 6d., 5s. 6d., 7s. 6d., 8s. 6d., 10s. 6d., 12s. 6d. 15 150 688 Ditto ditto with Ivory Handles and Gilt mountings 6s. 6d., 8s. 6d., 10s. 6d., 12s. 6d., 15s. 6d. 1 1 150 689 Ditto ditto mounted in buffalo Horn or Ebonite (fig. 689) 3s. 6d., 4s. 6d., 5s. 6d., 6s. 6d., 7s. 6d. 10 6 12 6 NEGRETTI & ZAMBRA'S THERMOSCOPIC SPECTACLES, FOR THE RELIEF OF WEAK, DIM, AND IMPERFECT VISION. Enabling the wearer to read or work with comfort by Gas or Candle-light. 690 These Spectacles are the result of a series of experiments, undertaken with the view to the manufacture of a glass that should possess the power of arresting the heat that proceeds from gas-light and other sources of artificial illumination. This desirable end having been attained by Messrs. NEGEETTI AND ZAMBEA, they are enabled to supply Spectacles, the glasses of which possess this peculiarity; that is to say, that the great heating power of gas and other artificial light is rendered imperfectly inert as far as regards vision, and the amount of light that enters the eye nearly equal to that which would do so through ordinary glasses ; by this means the unsightly dark glasses are superseded, and greater comfort is secured while reading or working by gas-light; at the same time the sight is preserved from the pernicious effects of the heat, and the eyes are kept as cool as when reading by ordinary daylight. The Thermoscopic Spectacles will be found, therefore, to recommend themselves to those whose avocations require great application to the desk, more especially during 'the winter months, in the banks and public offices generally, where of necessity a vast amount of writing and accountants' work has to be done by gas-light. Price, in Best Steel Frames, with either Convex or Concave Lenses 15 to 1 1 691 692 693 694 695 696 697 698 699 700 701 702 703 5, COKNHILL, E.G., AND 122, REGENT STRKET, W., LONDON. k D 223 FIG. 700*. FIG. 696. FIG. 691. FIG. 695. 'MAGNIFIERS AND POCKET MICROSCOPES. Flower Microscopes, folding up into convenient size, with neat cases for the pocket (fig. 691) Gardener's Microscope in case (fig. 692) .... Seed Microscopes, with glass body, in case . . 2s. Beetle or Insect Microscopes, convenient for examining living insects . '. . . . 3s. 6d. Ditto ditto large size, best mounted (fig. 695) Botanical Microscopes, with three powers, mirror, &c., in pocket case (fig. 696) 6 10 5 7 046 076 10 6 15 FIG. 692. FIG. 698*. FIG. 698. FIG. 697. FIG. 697 026 Cloth Microscopes or Linen Provers, for ascertaining the number of threads in a given space of linen, cloth, &c., in round case (figs. 679 and 697*) Ditto ditto folding for Pocket (figs. 698 and 698*) 2s. 6d. Ditto ditto for Coarse Goods, extra large Watchmakers' and Engravers' Magnifiers (fig. 700) Is. Pocket Magnifiers, in Horn mountings (fig. 701) . Ditto ditto two lenses Ditto ditto, three ditto (fig. 703) . . .3s. Ditto ditto one, two, or three lenses, in Tortoise-shell mountings (fig. 704) 5s. 6d. 10 6 15 Ditto ditto Tortoise-shell and Gold. Pearl and Silver mountings with Single or Double lenses, (fig- 705). Prices various. 224 NEGKETTI AND ZAMBEA, HOLBORN VIADUCT, E.G. FIG. 701. FIG. 705. FIG. 703. FIG 706. FIG. 708. 706 Stanhope Lenses, in German Silver mountings (figs. 706 and 706*) 036 Ditto ditto in Tortoise-shell ditto 10 6 Each. Each. s. d. s. d. 707 Ditto 050 12 6 ditto, in Silver ditto 10 6 15 FIG. 704. 708 Stanhope Lens, mounted with shade for the eye, and tube for improving the definition, magnifying power 180 diameters (fig. 708) This powerful and convenient lens is the invention of Lord Stanhope. The portability, low price, and the facility with which iti can be used, recommend it strongly. With it may be seen the animalcule in water, eels in paste and vinegar, farina of flowers, the down of moths, &c. ; and if a drop of solution of salt be spread lightly over the end of the lens, and viewed without delay, the formation of crystals will be beautifully seen. 709 Coddington's Spherical Lens, in German silver Mounting 3s. 6d. 5 710 Ditto ditto in Tortoise-shell . . . . 10 6 711 Ditto ditto in Silver 15 712 Pocket Magnifier, with two plano-convex lenses, diaphragm, and a Stanhope or Coddington lens, in Tortoise-shell mountings (fig. 712) . . 12s. 6d., 16 6 12 6 FIG. 712. 10 15 1 5 150 The most useful pocket magnifier or microscope introduced, magnifying power 10 to 80 diameters. 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 225 VARIOUS OPTICAL INSTRUMENTS, FIG. 743. FIG. 741, FIG. 742. 713 Concave and Convex Mirrors, Silvered Glass, in turned Wood Frames 16s., 21s., 714 Multiplying Mirrors 10s. 6d. 715 Black Mirrors, for Artists 716 Burning Glasses, in Horn mountings . . .2s. 717 Glass Prisms, for showing Decomposition of Light, of various sizes . . . ' . . 2s. 6d., 5s. 718 Glass Prisms, two in a neat box for exhibiting the Decomposition of Light into the Prismatic Colours and their Recomposition into White Light, &c. 719 Prism Compound of Flint, Crown, and Plate Glass 720 Prisms mounted with Ball and Socket joint adjustment on Brass foot . . , 721 Hollow Glass Prism, for experiments on the refraction of Fluids, and for Spectroscopes .... 722 Multiplying Lenses, in frame .... 2s. 6d. 723 Claude Lorraine Glasses, for studying the effect of colour upon Landscapes, &c 724 Colour Tops, a simple contrivance for exhibiting the recomposition of white light from colours 725 Apparatus for ditto ditto, on a larger scale, with multiplying wheel, on Stand with Circular Prismatic Disc (fig. 725) 726 Kaleidoscopic Colour Top, with perforated discs and coloured diagrams, complete ; in box . 727 Concave Lenses, in frame, for viewing Engravings, &e. Each. Each. s. d. s. d. 220 150 110 026 1 1 030 15 6 500 1 10 1 16 050 10 6 160 066 1 10 6 1 16 220 1 10 050 1 1 10 6 2 10 12 6 110 0-10 6 to 2 2 Q 226 NKGKETTI AND ZAMBRA, UOLBOKN VIADUCT, E.C., FIG. 725. FIG. 736. Each. s. d. Each s. d. 33 15 22 20 1 10 33 728 Graphoscopes, see page 228 729 Diagonal Print Machines, for viewing Prints, &c. . 730 Cosmoramic Frames and Lenses . . . . 731 Print or Map Lenses, various mountings and sizes, see page 222 732 Cylindrical Magnifying Lenses, in Yulcanite mount- ings, 10s. 6d., 12s., 14s., 16s,, 21s., 25s., 30s., 35s. 2 733 Cylindrical Mirrors, with 6 diagrams .... 734 Mirrors, Conical, with 12 diagrams ..... 735 Camera Lucida, Wollaston's (Chambre Claire}, for drawing in true perspective, in case (fig. 735) . 736 Ditto ditto, best form with Shades, &c., (fig. 736) 737 Portable Stand for ditto . 738 Camera Lucida, for Microscope .... See Micro Section 739 Beale's Neutral Tint Camera or Reflector, for ditto. See also 740 Draughtsman's Camera Obscura (Chambre Noire), for sketching (fig. 740) ..... 21s. 741 Ditto ditto improved Portable (fig. 741) . 742 Cosmorama or Camera Obscura, for Gardens, r &c., fitted up to order (fig. 742) 743 Prisms, Piano-Convex, in Brass mountings, with sliding adjustment ( fig. 743 ) for constructing Garden Cameras (as fig. 742), of various dimensions and foci . . . 38s., 45s. 2 10 5 10 33 1 10 1 15 2 10 55 22 1 15 220 660 45, COBNHILL, E.G., AND T22, REGENT STREET, W. ; LONDON". 227 FIG. 760. 744 FIG. 744. FIG. 761. Each. s. d. 056 15 1 10 Set of Five Lenses of various forms and curves, (fig. 744), with a small Prism to illustrate the Science of Optics, in a hinged case ...... 745 Model of the Human Eye, showing the position of various humours and Lenses, and for demonstrating the cause of Presbyopia or Long Sight ; Myopia, Short or Near Sight, &c., &c. In Mahogany Box 746 Kaleidoscopes, with two or three reflecting planes 2s. 6d. Ditto ditto, on Table Stand 7s. 6d., 10s. 6d. 747 Chromeidoscope, a modification of the Kaleidoscope 748 Debuscope, or Table Kaleidscope, with Plated Metal Reflectors 749 Spectroscope, for Chemical research. See Chemical Section 750 Photometers, Wheatstone's 751 Ditto for Gas Testing . . See Chemical Section 752 Radiometer, Crook's . . . ditto ditto 753 Goniometer, Wollaston's, for measuring the angles of Crystals ......... 754 Anorthoscope, with twelve diagrams (fig. 725) 755 Praxinoscope, a novel and pleasing arrangement of the above with six coloured pictures . . . 16s. 756 Polemiscope, by means of which any object may be seen, though an opaque body be placed before it 757 Phantascope, for exhibiting the illusion effected by a concave mirror, projecting figures in air . 758 Polyorama, with six views, so constructed that day and night effects are produced by means of reflected and transmitted light 759 Videoscope, for Reading, Drawing, Engraving, &c., having a clamp to screw the Instrument to the table, with joint and sliding adjustment with clamp . 760 Visuometer, Photographic (fig. 760), for enabling the artist to judge the effect of a landscape, folding for the pocket ......... 761 Focussing Glass, Photographic (fig. 761), for obtaining a perfectly sharp image on the focussing Screen of the Camera ......... Lenses or Prisms of all kinds made to order. Models and Diagrams to explain and demonstrate the Elementary Optics, the Theory of Vision, the construction of Refracting and Reflecting Simple, Compound, and Solar Microscopes, &c., &c, supplied to order. Q 150 12 6 Each s. d. 150 1 16 6 1 10 110 220 10 6 2 10 330 550 220 1 15 330 440 220 1 10 6 046 16 Laws of 228 NEGEETTI AND ZAMBRA, HOLBORX VIADUCT, E.G., FIG. 762. NEGRETTi AND ZAMBRA'S GRAPHOSCOPE, FOR VIEWING PHOTOGRAPHS, DRAWINGS, AND PICTURES OF EVERY KIND, As constructed and Patented by its Inventor, Mr. C. J. ROWSELL, and shown in the class " Scientific Inventions," at the International Exhibition (1871). So simple is this instrument, that little need be said as to the mode of using. It can be focussed to suit any sight the oldest or youngest, the longest or shortest. Plain or Coloured Photographs, when viewed through the Large Lens, will be found to stand out with the roundness and reality of natural objects. It occupies little space, cannot get out of order, and is an ornament to any drawing-room. The G-raphoscope may be used either by day or night. In the beautiful Photographic "Nature Printing," there is much that the unassisted eye cannot perceive, but which appears among the distincter portions portrayed, as a dark or light mass only. The Graphoscope, by a simple but effective arrangement, and a powerful Lens easily adapted to any focus, " brings out " and gives a Stereoscopic life-like effect to this, and to the whole subject in a very pleasing and beautiful manner ; also, by a simple combination, it forms a perfect Stereoscope for both Opaque and Transparent views. The Graphoscope, with an appropriate selection of Coloured or Plain Photographs, forms a most elegant Wedding or other Present. Each. Each. s. d. s. d. 762 No. 1. Graphoscope, Ordinary Size, with Stereoscope, Mahogany (figs. 762 and 762*) 2 12 6 763 No. 2. do. do. Walnut . . 330 764 No. 3. Large Size do. do. . . 550 No. 3*. Extra do. do 660770 765 No. 4. The Piccolo, a small Instrument . . . 1 10 1 16 Negretti and Zambra have always in Stock a collection of Photographic Yiews of London and various parts of the World Photographic Flowers and views of the Crystal Palace, Sydenham both coloured and plain, Statuary, &c., &c. 766 Plain Photographic Yiews, 2s. 6d., 4s. 6d. ; Coloured Flowers and Yiews, 4s. and 5s. A vase containing a bouquet of Natural Flowers placed in the field of the large lens forms an exceedingly interesting object. When the Graphoscope is used for this purpose it should have the easel turned down flat upon the base. Cartes de Visite, Portraits, &c., are very effective under the Instrument. STEEEOSCOPES. FIG. 767. FIG. 768. 767 Stereoscopes, plain metal or mahogany (fig. 767) . 768 Ditto ditto mahogany, with adjusting eye-pieces (fig. 768) . 769 Stereoscopes, divided form (fig. 769), papier mache body, covered with leather, and brass adjusting mounts, with glass mirror Each. s. 5 10 1 770 Ditto ditto Walnut or other woods, with ornamental mountings 2 FIG. 769. FIG. 771. PATENT COSMORAMIC STEREOSCOPES. 771 Cosmoramic Stereoscopes, Mahogany or Walnut wood, with Prismatic Lenses (fig. 771) 7s. 6d., 10s. 6d. 15 772 Ditto ditto Japanese Mounting (fig. 772) FIG. 772. FIG. 773. PATENT STEREOSCOPES WITH ADDITIONAL LENSES ADAPTED FOR SHORT SIGHT. 230 NEGBETTI AND ZAMERA, HOLBORN VIADUCT, E.G., Each. Each. s. d. s. d. 773 Stereoscope, with extra Lenses for Short Sight, in Mahogany or Walnut wood (fig. 773) ... 220 774 Ditto ditto in Papier Mache, divided form, covered with leather and ornamental mounts of various forms 2 10 330 NEGRETTI AND ZAMBRA'S PATENT MAGIC STEREOSCOPES. The great advantage offered by the " Magic Stereoscope " over all other descrip- tions of the instrument is its power of en- larging the slides seen through it to such an extent as to render them perfectly real in appearance, as though the scenes themselves were actually presented to view. Speaking of the Magic Stereoscope, the writer in the Art Journal says : " This instrument possesses advantages over every modification which we have yet examined. After a careful examination of all the conditions of the Magic Stereoscope, we are bound to state that it is by far the greatest improvement which has been made in this most interesting instrument." The prominent position the Magic Stereoscope has now for more than twenty- five years held, the favourable opinion ex- pressed of its merits by its numerous pur- chasers, and the steady and increasing de- mand, not only in Great Britain, but in all our Colonies, in America, and on the Continent, and, moreover, the entire absence to the present time of any competing instrument of higher pretensions, all combine to estab- lish its great superiority, and to confirm the opinion concerning it expressed in the critique in the Art Journal quoted above, Messrs. NEGRETTI AND ZAMBEA are the Sole Manufacturers of Mr. COOK'S Patent Magic Stereoscope. FIG. 775. 774 Patent Magic Stereoscope, in Walnut, with Achromatic Lenses, on sliding telescopic stand (fig. 774*), with rackwork adjustment for focussing . . . . 10 10 45, COKNIIILL, E.C., AND 122, REGENT STREET, W., LONDON. 231 FIG. 780. Each. s. d. 775 Negretti and Zambra's Patent Magic Stereoscope, in its most perfect form, with Extra Sized Lenses throughout, the intermediate lenses, Patent Cylindrical, for insuring a perfectly flat, colourless field and freedom from distortion (as fig. 775) . . from Each. s. d. 18 18 777 778 779 NEGRETTI AND ZAMBRA'S ACHROMATIC STEREOSCOPES. Achromatic Stereoscopes, with Opera Glass adjustment (fig. 776), in various plain mountings . . 25s. 1 15 2 Ditto ditto ornamental mountings . . .220 3 Achromatic Stereoscopes, with Rackwork Adjustment and extra large Achromatic Lenses, high magnifying power, suited for Glass Stereoscopic views . . 2 10 3 Ditto ditto mounted on Adjusting Stand . . .440 5 780 The Cabinet Form Stereoscope, in Walnut with Rackwork adjustment, mounted on adjusting stand, with Brass Slides and Clamps (fig. 780) ... 5 50 660 232 NEGEETTI AND ZAMBRA, HOLBORN TIADUCT, E.C , FIG. 782. PATENT REVOLTING OR MAGAZINE STEREOSCOPES. 781 Magazine Stereoscopes, to hold and exhibit twenty-five transparent Glass, or fifty Paper Slides. 440 550 782 Ditto ditto with Achromatic Lenses (fig. 782), to hold fifty Glass Yiews. 770 880 10 10 783 Magazine Stereoscope, to hold 100 Glass Yiews, with convenient adjustments . from 12 12 783* Magazine Stereoscope, very hand- somely Carved and Ornamented, to hold 100 Glass Yiews. 25 to 30 FIG. 784 Each. Each. s. d. s. d. 784 Hand Stereoscope (fig. 784), for rapidly looking over a series of Stereographs 15 6 784* Folding or Book Stereoscope, with Leather cases . . 10 6 15 GLASS STEREOSCOPIC YIEWS. 785 Negretti and Zambra's Series of Glass Stereoscopic Views, Price 3s. 6d. and 5s. each : England. Venice. London and Environs. Germany and the Rhine. Scotland. Belgium and Holland. Ireland. Denmark. France. Norway. Spain. Sweden. Italy. Russia. Rome. Constantinople and Athens. India. Switzerland. America. Pompeii. Egypt and Nubia. Holy Land and Syria. China. Japan. Siam. Moluccas. Java. 45, CORNI1ILL, E.G., AND 122, EEGENT STREET, W., LONDON. 233 STEREOSCOPIC YIEWS OF THE CRYSTAL PALACE. 786 Negretti 'and Zambra's Collection'of Crystal Palace Views, upon Glass and Paper, comprising all the most interesting views of the building and various Courts, Statuary, &c. Glass 036 each Paper 010,, PAPER STEREOSCOPIC YIEWS. 787 Paper Stereoscopic Views of the following places, price Is. each. England. Holy Land. France. London and Suburbs. India. Belgium. Scotland. China. Spain. Wales Italy. Holland. Ireland. Switzerland. Pompeii and Herculaneum. Egypt and Nubia. America. &c., &c. BOXES AND CABINETS FOR PRESERVING STEREOSCOPIC PICTURES. Each.^ Ea s ch - d 788 Plain Mahogany Boxes, to hold 100 Paper Views . . 10 6 to 1 5 6 789 Ditto ditto better quality for Glass Views .220 330 790 Elegant Cabinet Boxes, to hold a Stereoscope with a selection of Glass and Paper Views, &c., &c. ; of various forms and mountings . . . 3 3s. 4 4 550 Messrs. Negretfci and Zambra received a Prize Medal, 1851. Honourable Mention, Paris, 1855. The Austrian Gold Medal For Stereoscopic Views on Glass. Two Prize Medals, 1862, "For beauty and excellence of Photographic Transparencies, and adaptation of Photography to Book Illustration ; " and "For many Important Inventions and Improvements, together with accuracy and excellence in Objects Exhibited." 790* NEGRETTI & ZAMBRA'S NEW MILITARY BINOCULAR. This Binocular is specially designed for Service in the Field. Optically, is of high power ; gives a large field of view, abundance of light, and perfect definition. A Glass, to be really useful for Active Service, should possess the characteristics of mechanical strength, optical perfection, and be handy either on foot or in the saddle ; these qualities are pre-eminently united in the New Military Binocular. For Price, See Series IV., No. 796, page 236. 234 NEGRETTI AND ZAMBRA, HOLBOKN VIADUCT, E.C., NEGRETTI & ZAMBRA'S OPERA, RACE, FIELD, AND MARINE GLASSES, FIG. A. & 791. NOTICE. All Binocular Glasses named in the present List are comprised in Series and Numbers, ranging from 1 to 7 ; but as some of the numbers are omitted in certain Series, it will assist in the selection of any particular Glass if reference is made to the following Table, where the approximate size of the Object Lenses is marked opposite each Number. These Numbers apply to any one of the Fourteen Series. Glass No. 1 2 3 4 5 6 7 Size of Object Lenses, 1 inch. If IS 4 If 791 Twelve-lens Achromatic Binocular Race Glass (fig. A), (having Triple Combination Eye and Object Lenses) very powerful, great field of view. with Solid Leather Case and Strap 660 Aluminium ditto ditto 12 12 See also No. 6, Series I. 45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 235 SERIES I. 792 Binocular Field or Race Glasses, 12-lens Combination. The eye-lenses in these Glasses being larger than those usually supplied, a much greater field of view is obtained. They are mounted in bronzed metal, the bodies covered with leather, and are made in seven sizes, all equally adapted for land, sea or in-door use. (Fig. c.) Nos. 1, 2, and 3 are supplied in Soft Leather Cases, and admit of being carried in the pocket, where larger glasses would be inconvenient. No. 1 2 10 No. 5 55 ,,2 330 ,,6 66 ,,3 3 15 ,,7 6 15 ,,4 440 No. 6, fitted with Double-Draw Arrangement, giving higher power, (fig. B.) 7 7 No. 4, 5, 6, and 7 are supplied in Solid Leather Cases, with sling straps. These Glasses are also mounted in ALUMINIUM (about half the weight of those in ordinary metal). (Fig. E and p.) No. 1 2 3 5 6 7 No. 4 5 6 88 10 10 12 12 No. 6, fitted with DOUBLE-DRAW ARRANGEMENT, 14 14 0. (Fig. 236 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., SERIES II. 793 Binocular Glasses for Races and general out-door use, fitted with 12 lenses, giving very great power and definition. (Fig. A.) They are mounted in metal, Enamelled black. The bodies and sunshades covered with leather. These Glasses are made in 3 sizes, and supplied in Solid Leather Cases with sling straps. No. 4 440 ,,5 550 ,,6 660 If mounted in Aluminium (either bright or Enamelled black) No. 4 880 ,,5 10 10 6 . . 12 12 794 Binocular Glasses, with MOYEABLE CENTRES to change the position of the lenses to adapt them to suit the width between different eyes, from 10s. to 15s. each extra. SERIES III. 795 The " Staff-Officer " Binocular Field Glass, 12-lens Combination. This celebrated Glass is made in No. 6 size only. It has great power and gives very fine definition. N. & Z. strongly recommend this Glass to Officers in the Army, where there are no restrictions as to size. The mounting and sunshades are of bronzed metal, and the bodies covered with Russia Leather. Price, including Solid Leather Case, 7 7 0. (Fig. H.) Ditto with Double-Draw arrangement, giving higher power, 8 8 0. (Fig. G.) SERIES IY. 796 The " New Military " Binocular. This is made in the fifth size only, to fit the Army Regulation Pouch. (Fig. i.) The mountings and shades are of bronzed metal. The bodies covered with black or buff leather, with Solid Leather Cases to match. Price, 550 Ditto, in Bronzed Aluminium, 9 9 0. An allowance of 7s. 6d. is made if the Case is not required. Regulation Pouches supplied to order. 45, COSNHILL, E.C , AND 122, EEGENT STREET, W., LONDON. 237 SERIES Y. 797 Binoculars, for Marine, Field or Theatre use. The magnifying power and field of view of these Glasses can be varied to suit near or distant objects by means of a Revolving Eye-Piece containing Three Powers. (Fig. K.) The mounting is metal, japanned black. The bodies covered with Black leather. These Binoculars are all supplied in Solid Leather Cases and are made in four sizes. No 3 4 D No. 3 , 4 . . . . .4 4 No 5 , . . . 5 5 6 ill Aluminium . . .8 8 No. 5 , 10 10 6 6 7 12 12 . 14 14 SERIES VI. 798 Binoculars intended chiefly for Marine Service. Fitted with 6-lens combina- tion, and strong bronzed metal mounting, No. 7 size, 5 5 0. (Fig. J.) Ditto, 12-lens Combination, Government Pattern, No. 7 size, 5 5 0. (Fig. L.) Ditto, 6-lens Combination, No. 6 size, 4 4 0. All Glasses in this Series are supplied in Solid Leather Cases, with Strap. The Glasses in Series I. are also adapted for Marine purposes. SERIES VII. 799 BinoculariField Glasses. 6-lens Combination, fitted with extra long adjusting tubes, by which greater power is obtained. (Fig. Q.) N. & Z. recommend this Series where a 12-lens Glass would be too costly. They are mounted in metal, japanned black, and the bodies covered with leather. Prices, including Solid Leather Cases, with Strap : No. 3 size 4, 99 ** 99 2 2 2 10 No. 5 size .* 6 3 4 OPERA GLASSES SERIES VIII. 800 Opera Glasses, very highest quality, fitted with 12-lens combination, and mounted in ALUMINIUM. The bodies covered either with Mother-o' -pearl or Tortoiseshell. (Figs. M. and N.) These Glasses are very suitable for Wedding or Birthday Presents, and are made in 5 sizes. No. 1 , 2 sizes. 5 5 No. 3 6 6 ,, n 5 770 880 10 10 P Q R SERIES IX. 801 Opera Glasses, similar to those in Series VIII., but mounted in ALUMINIUM (either bright or enamelled black) the bodies being covered with Morocco leather. p - No. 1 2 4 10 5 10 No. 3 4 ,,5 6 10 7 10 8 10 An elegant Morocco leather or Velvet Flexible Case given with each of the above Opera Glasses. SERIES X. 802 Negretti & Zambra's best quality Opera Glasses, with Ivory bodies and Gilt Metal Mountings, fitted with 12-lens combination. Suitable for presents where aluminium mounted glasses are too expensive. (Fig. o.) No. 1 2 10 ,,2 330 ,,3 440 Ditto with 6-lens combination. No. 1 1 10 ,2 ,220 No. 4 5 No. 3 5 6 2 10 3 3 4 4 NEGHETTT AND ZAMI5RA, HOLBORX VIADUCT, B.C. 239 SERIES XL 803 Opera Glasses, best quality, with Mother-o'-pearl bodies and Gilt Metal Mountings, fitted with 12 Lenses. No. 1 3 3 I No. 3 ,.2 4 4 I 4 Ditto with Dark Pearl Bodies and Mountings Enamelled Black. No. 1 2 10 I No. 3 ,2 3 3 4 5 5 . . . 6 6 lamelle d Black. 4 4 5 5 SERIES XII. 804 Negretti & Zambia's new pattern, 12-lens Achromatic Opera Glasses. (Fig. E.) The mountings are Bronzed Metal and the bodies covered with Morocco leather. N. & Z. strongly recommend this Series, where a best instrument is required in plain but strongly made mountings. No. 3 size . . . .330 No. 1 size . . . .220 4 . . . . 3 10 ,,2 2 10 I 5 440 SERIES XIII. 805 Negretti & Zambra's 6-lens Opera Glasses, made in 5 sizes, either of which can be recommended as a good and useful glass for general purposes. (Figs, s T TJ.) .110 .150 . 1 15 No. 4 size . . . .220 5 330 SERIES XFV. 806 Monocular Field or Opera Glasses, best quality, mounted in metal, japanned black, and body covered with Morocco leather. , (Fig. v.) No. 1 size . . . 10 6 No. 5 size . . . 1 10 2 . . 15 6 . . . 1 15 3 . . .110 7 (Fig. v.) . 2 2 , 4 , 150 Prize Medal, 1851. Two Prize Medals, 1862, FOR MANY IMPORTANT INVENTIONS, ACCURACY, AMD EXCELLENCE. FIG. 810.- NEGRETTI AND ZAMBRA'S ALUMINIUM BINOCULARS. 807 The only novelties in Opera and Field Glasses exhibited at the International Exhibition of 1862 were two by Messrs. Negretti and Zambra ; viz., the use of Rock Crystal for lenses, and Aluminium for the mountings ; the extreme hardness and brilliancy of the one, and the wonderful lightness of the other, render them eminently useful in the construction of Field Glasses, &c. The principal use of Rock Crystal is for instruments required for service in Tropical climates, where the great heat, combined with moisture, cause the ordinary glass lenses to become dull and stained. The Rock Crystal retains its polish, gives a very brilliant image, and is not so liable to become scratched as Glass. 808 Rock Crystal 12-lens Combination Binocular Field Glasses, with Solid Leather Sling Cases and strap .... 10 10 The difference of weight between Aluminium and the usual metal mountings of Field Glasses, &c., is so great as always to excite astonishment, certainly one- third less ; so that a very large instrument can be used with the greatest ease and comfort. This extraordinary lightness is very valuable in hot climates, where the slightest exertion becomes distressing, and a useful instrument is often thrown aside on account of its weight. Negretti and Zambra are now manufacturing Aluminium Opera and Field Glasses in a variety of sizes and forms, fitted with the very finest lenses, weighing about one-third less than the ordinary instruments. 809 Aluminium Opera Glasses. See Series YIII. and IX. 810 Ditto Field Glass, as fig. 810 .. . . 10 10 12 12 NEGRETTI & ZAMBRA'S IMPROVED YACHiTING AND DEER-STALKING 811 These Binocular Telescopes are, from the adjustments, suitable to every sight and width of eyes. The Field is large and clear, with an abundance of Light, while the Magnifying Power is great. By the new adjustment, the circles of the two Fields are made to coincide exactly, so that all strain is taken from the eyes in looking through them; while the breadth of the Field enables the observer to " pick up " any object at once. Negretti and Zambra recommend their Binocular Telescopes for Yachting, Deer-Stalking, Military Service or general Field use. PRICES. (Fig. 811.) IN BRONZED METAL. FIG. 811. No. 1, Binocular with Leather Sling Case 2 3 4 Magnifying Power. 100 times 150 200 250 Diameter of Height when Object Lens. Closed up. . IJ-in. . 9-in. If Hi IN ALUMINIUM. (About half the Weight of those in Ordinary Metal.) No. 1, Binocular with Leather Sling Case 100 times . l-in. . 9-in. 2 . 150 . If . 10| 3 . 200 . 1$ . 11* ,4 .250 U 14^ a. d. 850 9 15 11 10 13 10 12 15 16 18 10 20 5 812 Negretti and Zambia's new "Binocular" Telescope. By a further improvement in the arrangement and combination of Lenses NEGRETTI & ZAMBRA have now produced a Glass of only eight inches in length, possessing all the advantages of the largest Binocular Telescopes. Great Reduction of bulk and weight, combined with High Magnifying Power, and large Field of Yiew are the special points recommending these New Binocular Telescopes. PRICES. (Fig. 812) Mounted in Bronzed Metal, with Leather Sling Case. 12 10 Mounted in Aluminium 16 10 FIG. 812. NOTE. Negretti % Zambra also manufacture a smaller Binocular Telescope, No. O, with Object Lenses 1 inch diameter ; "but the field of view being extremely limited, they recommend in preference their 12-Lens Binocular Field Glasses, No. 6, at 6 6s. and 7 Is. Sec Series 1 and 3, pages 234 and 236. B 242 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, B.C., TELESCOPES. FIG. 817. POCKET TELESCOPES. Each. s. d. 813 Perspective Glasses, with mahogany or japanned body, and one, two, or three draws . . Is. 6d., 2s. 6d. 3 6 814 Pocket Telescopes, two or three draws, with Achromatic object lens, Mahogany or Leather Covered body (figs. 814) 10 6 815 Ditto ditto Each. s. d. 070 12 6 with Sun Shade 15 16 FIG. 8H. FIG. 819. FIG. 814. 816 Achromatic Telescopes, with Leather Case and Sling Strap 150 1 10 817 Achromatic Telescopes, with Screw and Jointed Clip for fixing to a tree or at side of Window, &c. (fig. 817) '21s. 150 1 10 Ditto Ditto with Astronomical Power, in a neat Mahogany Box 150 818 Pocket Rifle Telescope, Achromatic, one draw, body covered with leather, with light sling, small, portable, and very powerful, to show Bullet marks at 300 to 500 yards 1100 220 819 Pocket Achromatic Telescope 3 draws 24-inch, If -inch Object Lens (fig. 819) . 220 820 Ditto, with Sun Shade 2 10 821 Pocket Achromatic Telescope 3 draws 30-in., If -inch Object Lens . 330 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 243 FIG. 822. Each. Each. s. d. 822 Pocket Achromatic Telescopes, with Mahogany or Rosewood body (fig. 822) : Two, three, or four draw Brass Telescopes with Lenses of the VERY FINEST QUALITY AND BEST MOUNTING 12-inch 1 15 18-inch ditto ditto 2 10 24-inch ditto ditto 3 10 30-inch ditto ditto 440 550 36-inch ditto 4 -draw, Extra Large Object Lens 7 It) 823 Pocket Achromatic Telescope solid German Silver Mountings, with Sun Shade, 21-inch three draw, best quality (fig. 822) 4 10 824 Ditto Ditto 30-inch 5 10 825 Pancratic Eye Tubes (Dr. Kitchener's), to above extra 12 6 110 822 and 823 are very suitable for Rifle Prizes, especially if fitted with Pancratic Eye Tubes. 826 Solid Leather Cases and Sling Straps for any of above, from each extra 10 6 FIG. 827. 827 12-inch Pocket Military Reconnoitring Telescopes, best quality, six draws, very portable, brass tubes Ditto ditto German Silver tubes (fig. 827) 18-in. ditto six-draw Brass tubes 24-in. ditto seven- draw ditto .... 30-in. ditto eight-draw ditto . . ... 1 10 2 2 2 10 3 10 4 10 FIG. 828. 828 Negretti and Zambra's Improved Achromatic Military Reconnoitring or Deer-Stalking Telescope, two or three draws, with Sun Shade, bronzed tubes, and mounted in strong leather body with sling strap, or in Leather Case with Sling (fig. 828) No. 1 o 1 15 2 10 440 No. 4 550 6 10 880 JVbs. 3, 4, 5, and 6 are fitted with Pancratic Eye-pieces. 244 NEGRETTI AND ZAMBEA, HOLBORN VIADUCT, E.G., THE "MAC LEOD" DEER-STALKER. 829 Fitted with three draws, Taper Body, with Sun Shade and Pancratic Eye-Piece, Object Glass 2^-in. dia- meter. Supplied in solid leather case, with sling strap .......... Ditto, ditto Bronzed German Silver, with Leather Case and Sling, exceedingly light but strong . N. & Z. recommend this pattern as being one of the finest Telescopes it is possible to employ for Deer Stalking. Each. Each. s. d. s. d. 6 10 10 830 Aluminium Telescopes, two or three draws, very light, Large Object Lenses. Suitable for Presents, or for Ladies' use, fitted in leather cases, with sling straps . 10 10 12 12 MARINE TELESCOPES. FIG. 832. 831 Marine or Day and Night Achromatic Telescopes, yielding a large field and full body of light, adapted for Coast Service .... 21s., 30s., 40s. 2 10 330 832 Day or Night Achromatic Pilot Telescopes, with one, two, or three draws (fig. 832) 220 2100 FIG. 833. 833 Pilot Telescopes, One draw with Shade Tube (fig. 833) 330 440 834 Erect Night Telescope, with one draw and Shade Tube, Object Lens of large diameter and best quality .550 660 835 Large Inverting Night Telescopes 550 FIG. 838. Navy Telescopes, Taper Bodies, covered with leather, bronzed Tubes, and Sunshades, one draw tube, best Achromatic Object Glasses. No. 1 2 3 4 5 6 7 Length when closed. 12 inches 15 18 21 24 26 30 , 45 Diana, of O. G. 1^ inches If . If . 1* . Price. 2 2 2 10 3 3 10 4 10 5 5 6 10 7 10 45, CORNHILL, E.C., AND 122, REGENT STEEET, W., LONDON. 245 837 Navy Telescopes as above, but with polished German Silver tubes and Sunshades. 3 30, 44 0, 550, 660 and 880 838 Deck Telescopes, one draw with Spray shade, as fig. 838. No. of Draws. 1 1 1 Diameter of Object Glass. 1 inches Body covered with leather. 1 16 2 10 3 10 or Mahogany. 220 330 4 10' FIG. 840. Each. s. d. Each. s. d. 1 16 220 839 Deck Telescopes, large sizes of above with Hackwork and Sliding adjustment (fig. 839) 5 10 7 10 8 10 10 10 840 Midshipman's Telescope, 18-inch Brass taper body covered with leather, and Navy Signals inserted, sling strap (fig. 840) 841 Ditto Ditto, Regulation pattern, German Silver, with Navy Signals, Sun Shade, and sling strap 842 Marryat's Code of Signals fitted to Telescopes 843 Navy Code of Signals to ditto 844 Straps and Slings to ditto 845 Mariners' Compass, with Bar Needle or Floating Card fitted to cap of Telescopes, to order from 3 3 10 10 10 18 FIG. 839. 846 Signal Station or Target Practice Telescopes, for Telegraphic and Look-out puposes, or for distinguishing bullet marks on targets at the longest ranges with one draw, the bodies covered with leather, and with rackwork and sliding adjustments to eye-pieces (fig. 839). No. 1 2 3 4 Size of Object Glass. 2 inches . . 21',, . . 2* . . 2| . . 3 . . Tripod Stands for above, see over. Price. 4 10 5 10 8 10 10 10 12 10 246 NEGRETTI AND ZAMBKA, UOLBOKN VIADUCT, E.C., FIG. 848. FIG. 850. 847 Portable Tripod Stands} for Telescopes, of Wood, with Brass Bolts and Nuts 848 Ditto ditto with Vertical and Horizontal adjustments (fig. 848) 849 Ditto ditto Brass head, with jointed Clip, or Cradle Telescope-holder, mahogany legs (fig. 849) 850 Improved Alt -Azimuth Stand (fig. 850), for Astronomical Telescopes, well suited for Telescopes Nos. 853, 856, and 857 ; Strong Metal Mountings, very rigid, and conveniently portable .... Each. s. d. Each. s. d. 1 12 6 1 16 2 10 330 4 10 12 15 851 Captains' or Pilots' Binocular Night or Look-out Glasses (see pages 234 to 237). FlG. 852. 852 Negretti & Zambra's Traveller's Telescope consists of a highly-finished portable Telescope, with Folding Table Stand (fig. 852). 45, CORNHILL, E.G., AND 122, EEGENT STREET, W., LONDON. 247 It is fitted with Terrestrial or day eye-piece of high magnifying power and brilliant definition, and one Astronomical eye-piece of sufficient power to exhibit all the phenomena of the planets and divide the more easily resolved of the double stars. The whole instrument is compactly arranged in a mahogany box with lock and key, forming one of the most useful and convenient Telescopes for Tourists or Sea coast visitors. It can be used without the stand, as an ordinary pocket Telescope. Price, complete in case . . . . 7 7 0, 8 8 0, 10 10 ASTRONOMICAL TELESCOPES. FIG. 853. 853 Negretti & Zambra's Universal Telescope (fig. 853), with 2^-inch Object Glass, brass body, japanned black, fitted in case . . . .550 Ditto, with 3-inch Object Glass . . . . . . .660 Ditto, with polished brass body and extra Astro, eye-piece . .880 N. & Z., in view of the increasing demand for Astronomical Telescopes of moderate price, have constructed one that, while it accomplishes eifectually all required in an elementary study of the heavenly bodies, is equally useful as a Telescope for Terrestrial objects, or for marking in Rifle practice. It will show Jupiter's moons, Saturn's ring and moons, and resolve some of the double stars ; while for terrestrial objects, it will define well at a distance from 10 to 15 miles, and will show bullet marks on a target at the longest ranges. For Astronomical purposes, an extra eye-piece can be had, magnifying 80 diameters, price 12s. 6d. Can be added at any time. Firm Garden Stands for above, see page 246. 248 NEGBETTI AND ZAMBKA, HOLEORN VJADUCT, B.C., FIG. 854. 854 Negretti & Zambia's Signal Station or Telegraph Look-out Telescope, having Rackwork and Sliding Adjustments to the eye-tube, mounted on a strong steady tripod table stand, with universal movements and hinged clip for holding the Telescope, so contrived that when not in use, the Telescope can be quickly removed from its stand, and both be securely packed away in the stout case supplied with the instrument (fig. 854). No. 1 2 3 4 5 Length. 30 inches 36 40 44 48 Diam. of O. G. 2 inches These Telescopes have sufficient magnifying and defining power for distinguishing bullet or shot marks on a target at the longest ranges. Also well suited for Coast-Guard stations, or as a Sea-Side Look-out-glass. 855 Achromatic Astronomical and Terrestrial Telescope (fig. 855), bright Brass Body, Rackwork and Sliding Adjustment to eye-piece, mounted on a pillar and brass claw Table Stand, having Horizontal and Vertical motions ; fitted in polished mahogany case, with lock and key. Size of Object Glass. Terres. 2 inches. 1 2* .1 2* .1 3 1 Eye-pieces. Astro. Power. With Terres. Eye-piece. With Astro. Eye-piece. Price. . 20 diameters 45 diameters . 10 10 . 30 55 . 11 11 . 40 70 . 14 14 50 85 18 18 Tripod Out-of-Door Stands suited for above, see page 246. 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 249 FIG. 855. ACHROMATIC ASTRONOMICAL AND TERRESTRIAL TELESCOPE, No. 855. FIG. 856. 856 Achromatic Astronomical Telescope (Fig. 856), on handsome brass pillar and claw Table Stand, with Rackwork and Sliding Adjustments to Telescope, elevating and steadying rod, and Achromatic Finder, fitted in polished mahogany case, with lock and key. Size of Eye pieces. Power Object Glass. Terres. Astro. With Terres. Eye-piece. With Astro. Eye-pieces. Price. 3 inch .1 2 . 45 diameters 65 & 80 diameters . 25 3i .1 2 . 50 75 & 90 . 30 3i . 1 2 , 60 80 & 95 35 250 NEGRETTI AND ZAMBEA, HOLBORN VIADUCT, E.G. 857 FIG. 857. Achromatic Astronomical Telescope (Fig. 857), same as No. 856, but with Tangent Screw and Hook's Universal Joint for horizontal adjustment, and extra Steadying Rods to Telescope ; fitted in polished mahogany case, with lock and key. Power. With Terres. Eye-piece. With Astro. Eye-pieces. . 50 diameters . 55 . 60 70 Size of Eye-pieces. Object Glass. Terres. Astro. 3 inch . 1 2 3i . 1 2 3f . 1 2 4 . 1 2 75 & 90 diameters 80 & 95 85 & 105 90 & 110 Price. 36 42 48 66 EDUCATIONAL ASTRONOMICAL TELESCOPES ON IMPROVED TRIPOD STANDS. 858 Astronomical Telescope, on Taper Iron Tripod Stand, object glass 3 inches diameter, 3-ft. 9-in. focal length, one Terrestrial eye-piece magnifying 20 diameters, and two Astronomical eye-pieces, magnifying 60 and 125 diameters, vertical rack motion and Achromatic finder, fitted in stout case, with lock and key 25 859 Ditto ditto, on improved Tripod Stand, with object glass 3-in. diameter, 4-ft. 9-in. focal length, one Terrestrial eye-piece, magnifying 25 diameters, and three Astronomical eye-pieces magnifying 80, 155 and 230 diameters. Fig. 859 45 860 Ditto ditto, but with object glass 4^-in diameter, 5 -ft. 3-in. focal length, one Terrestrial eye -piece, magnifying 30 diameters, and three Astronomical eye-pieces magnifying 85, 170 and 255 diameters . . . 60 861 Telescope Stand, similar to Fig. 861, for large instruments, complete, with Vertical rack, Steadying rod and Horizontal tangent rack . 15 15 45, COKNHILL, E.G., AXD 122, BEGENT STREET, W., LONDON. 251 FIG. 861. 861 Negretti and Zambra's Educational Astronomical Telescope, No, 861, with Vertical and Horizontal screw adj ustments, Steadying Rod, &c. 252 NEGEETTI AND ZAMBEA, HOLBORN VIADUCT, E.G., FIG. 862. Each. s. 150 NEGRETTI & ZAMBRA'S EQUATORIAL TELESCOPES. 862 Negretti & Zambia's Universal Equatorial Telescope (fig. 862), with Object Glass 4-in. diameter, 4-f t. 9in. focal length, and four eye-pieces, magnifying 80, 155, 230, and 310 diameters 863 Ditto, ditto, but with Object Glass 4| in. diameter. 5 ft. 3 in. focal length, and four eye-pieces, magnifying 8*5, 170, 255, and 350 diameters, mounted on bronzed iron pillar 5 ft. 6 in. high . 200 864 Ditto, ditto, with Object Glass 5 in. diameter, 6 ft. focal length, and five eye-pieces, magnifying 65, 190, 195, 240, and 390 diameters ........... 275 865 Ditto, ditto, with Object Glass 6 in. diameter, 8 ft. 6 in. focal length, with five eye-pieces, magnifying 90, 140, 275, 410, and 550 diameters ; also an improved Diagonal Eye-Piece for Solar Observation and for viewing objects near the Zenith . . 420 Estimates given for Larger Instruments on application. Equatorial Telescope Stands From 42 45, COBNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 253 FIG. 867. Each. s. d. 866 Transit Instrument, 14 in., with Telescope having 1| in- aperture 880 Ditto ditto 24 in., on portable Iron Stand, with engine divided circle, Spirit Levels and Tangent Screw Adjustments . . 27 867 Ditto ditto 30 in., with Telescope having 2| in. aperture (fig. 867) 50 Ditto ditto with two Setting Circles and Brass Stand . . 60 868 Ditto ditto 36 in 70 869 Astronomical Clock, dead beat escapement, jewelled pallets, and Compensated Pendulum, with steel rod and Mercurial Cistern, in Plate Glass Case for hanging on wall 42 870 Mean and Sidereal Time Clock, showing both times on the same dial with dead beat escapement and jewelled pallets, with compensated pendulum and small bell to strike the minutes, in case, with Plate Glass top, sides and front . . . . . 88 871 Small Equatorial Star Finder, for the use of Students, 4-in divided circles, achromatic Telescope, with 1^ in. object glass . . 12 12 "With this instrument any Star or Planet can be found with facilty, and many important facts in astronomical science demonstrated. NEGRETTI & ZANBRA'S IMPROVED TRANSIT INSTRUMENTS. FIG. 868. FIG. 869. FIG. 870. 868 Portable Transit Instrument for the Determination of True Time. Plain Mounting with Box (fig. 868) .... Price 880 869 Ditto ditto ditto, with vertical divided Circle, with Box (fig. 869) 12 12 870 Ditto ditto ditto, with Illuminating Apparatus, the most com- plete form (fig. 870) with Box 15 15 Pull instructions for setting up and using the above Transit Instruments will be found in A Treatise on the Transit Instrument, by Latimer Clark, M.I.C.E., &c., price 5s. 871 Object Glasses, best quality, for Astronomical Telescopes, mounted in brass cells. 1 inch clear aperture 10 . 150 . 220 .350 . 4 15 . 700 . 9 10 . 14 . 22 . 42 10 . 75 . 125 . 200 . 300 . 400 Quotations for larger sizes may be had on application. NEGEETTI AND ZAMHRA, HOLBOEN YIADUCT, E.C. 255 Each s d 871 Telescope Eye-Pieces, Huyghenian .... 16s. to 1 5 872 Dawe's Solar 800 873 Transit 300 874 Terrestrial . . . ... 1 15 875 Comet 1 10 876 Diagonal 4 10 877 Sunshade and Brass Cap fitted to eye-piece 060 878 Micrometer, Double Image, with Eye Pieces, &c., in Box . . 20 879 Micrometer, with Position Circle, &c 15 880 Reflecting Telescopes, for Students' use, mounted on improved stand, with endless screw motion to follow the stars with Equatorial Motion, Silvered Glass Speculum, 5 in. diameter, with two eye-pieces 25 881 Ditto, Ditto on Equatorial stand, with 6^ in. speculum . 80 82 Ditto, Ditto with 85 in. Speculum and three eye-pieces . 110 883 Silvered Glass Specula (unmounted) best quality. 5J inch diameter 7 10 63 ..900 8* 17 10 10 . 38 Prices of larger sizes may be had on application. 884 Foucault's Reflecting Telescope, for Terrestrial or Astronomical observations. The improvements of this telescope are principally in the use of a Glass Speculum coated upon the surface with pure Silver. The eye-piece is an achromatic microscopic arrangement of lenses mounted on the side of the telescope, the image being received from the large speculum by a prism, and the reflected image examined by the Microscope Eye-Piece, which is fitted with rack-work adjustment. With these arrangements, high powers can be used, and large field of view, combined with light, obtained. Mounted on a table stand, with simple adjustments (fig. 884). Supplied to order . . 20 With simple instructions for re-silvering the speculum. Gregorian or Newtonian Reflecting Telescopes constructed to order. NEGRETTI & ZAMBRA'S MICEOSCOPES. FIG. 889. SIMPLE AND COMPOUND MICROSCOPES. Each Each s. d. s. cl. 885 Botanic or Dissecting Microscope, Simple Lenses, a variety of forms, with pillar to screw into the top of the box containing the apparatus . lls. 6d., 16s., 17 1 10 FIG. 892. FIG. 891. 886 Botanic or Dissecting Microscope, with Hackwork adjustment and apparatus, in Mahogany Box (fig. 886) 150 1 10 45, CORNHILL, E.G., AND 122, BEGENT STEEET, W., LONDON. 257 FIG. 891. 887 891 802 Each. s. d. Compound Microscope, with sliding tube adjustment, mirror, eye-piece, and magnifying power, forceps, and one microscopic object ; in a Mahogany hinged box Compound Microscope, with three magnifying powers and two objects and stage glass for holding water. &c., in Mahogany box (fig. 888) 16 Compound Microscope, with three magnifying powers, a mounted lens for condensing the light on opaque objects; in Mahogany box (fig. 889) . 110220 Compound Microscope, with sliding tube adjustment, mirror, four powers, objects, forceps, water trough, insect box, stage plates, glass tube, &c. (fig. 890) Each. a. d 10 18 2100 330 Large Compound Microscope, Martin's Improved, best finish, and lenses, with Rackwork adjustment (fig. 891) ..... 440 Dissecting 'or Mounting Microscope, improved form, arranged for medical or botanical investigation. The stage plate is made of stout glass, set in a circular brass rim supported on three legs; beneath the stage is a mirror, with convenient adjustment. This Microscope is fitted with three simple powers, ^-inch, 1-inch, and 2-inch focus. Arranged in a neat mahogany box, with brass forceps, &c. 220 Dissecting Microscope, similar to No 892, but with Compound Body, as fig. 892, having Rackwork adjust- ment, also 1-inch and ^-inch Achromatic Powers, in Mahogany Box, with brass forceps, &c. ... 440 258 NEGEETTI AND ZAMBRA, HOLBOEN VIADUCT, E.G., 894 FIG. 894, FIG. 895*. ACHROMATIC MICROSCOPES. Achromatic Microscope, with Jointed Pillar, and firm circular foot, Hackwork adjustment to the body, sliding clamp for objects on the stage, with a set of Achromatic lenses, brass forceps, &c. ; in Mahogany case (fig, 894) In three sizes, 1 10 220 330 895 895 896 Negretti and Zambra's No. 1 Microscope (suited for elementary instruction or amusement). Bronzed Stand, rack adjustment to the body, slide holder and diaphragm to the stage, forceps, stand condenser, two eye-pieces, and two sets of Achromatic Powers, in Mahogany cabinet . . 3 10 Negretti and Zambra's No. 2 Microscope, similar to No. 1, with Fine Adjustment to the body, and 1-inch and|-inch Achromatic Powers (fig. 895*) 4 10 Negretti and Zambra's No. 3 Microscope, similar to No. 2, and fitted with Polarising Apparatus 6 10 897 Negretti and Zambra's No. 1A College Microscope, with Brass stand, rackwork adjustment to the body, sliding object stage and holder, diaphragm plate, Achromatic object lens, dividing to ^-inch and ^-inch, in brass box, Live Box, brass forceps, &c. ; in Mahogany cabinet with lock and key and drawer (Fig. No. 1A), 3 10 898 Ditto Ditto Ditto, with Stand Condenser, Stage, Forceps .440 45, CORNHILL, E.G., AND 122, EEGENT STEEET, W., LONDON. 259 No. 1 A No. 2 B 899 Negretti and Zambra's No. 2B College Microscope, as 898, but with fine adjustment and lengthening tube to the body, separate object lenses, 1-inch and -inch, in brass boxes ; in Mahogany Cabinet . . 500 900 Negretti ] and Zambra's No. 30 College Microscope, with Mechanical Stage, giving adjustment in two directions, as No. 2 B, in Mahogany Cabinet with Lock and Key & 10 901 Negretti and Zambra's No. 4D College Achromatic Microscope, similar to No. 3 C, but with Polarising Apparatus ......... 10 10 902 Negretti and Zambra's College Achromatic Microscope, No. 5. Brass stand, with Mechanical Stage, Rackwork Adjustment and Lengthening Tube, to the body, Fine adjustment for the Object lens, rotating object holder, and diaphragm to the stage, two eye-pieces, three Achromatic Powers, 1 inch, ^-inch, and ^-inch, Polarising Apparatus with Selenite Spotted Lens, Stand, Condensing Lens, Animalculse Cage, Stage Con- denser and Forceps, Curved Forceps, Dipping Tubes, Stage Glasses, &c., &c. ; in Mahogany Cabinet 18 18 902 Negretti and Zambra's Student's Binocular Microscope, with convenient adjustment for width of eyes, Plain Stage, two Eye -Pieces, and 1-inch and |-inch Achromatic Object Lenses, Stand Condenser, Live Box, brass forceps, &c. ; in Mahogany cabinet . . . . .880 s2 NEGRETTI AND ZAHBRA, HOLBOEN VIADUCT, B.C., NO. 3 C. N0.4D. 903 Student's Binocular Microscope, as 902*, with Rackwork Adjustment to eye-pieces, and an extra pair of eye-pieces (fig 4D.) . . . 10 10 904 Negretti and Zambra's Student's Binocular Microscope, as No. 903, but with extra i-inch Power 12 12 FIG. 905. 905 The Naturalist's Portable Field Microscope, mounted on Folding Brass Tripod, with 1-inch Achromatic Object Lens, complete with Forceps, &c., in Mahogany Box (fig. 905) 3 10 906 Ditto ditto having 1-inch and i-inch Achromatic Lenses, Live Box, Forceps, Fishing Tubes, Stage Glasses, Stand Condenser, &c., &c., in Mahogany Box, very compact, invaluable, to Mineralogists, Botanists, Geologists, Entomologists or Travellers 4 10 45, COBNUILL, B.C., AND 122, EEGENT STEEET, W., LONDON. 261 FIG. 907. 907 Brewer's Microscope, specially constructed for the Examination and Selection of Hops, Yeast, Malt, Sugar and Water previous to use for Brewing. Fitted with one Eye-piece, 1-inch and -inch Achromatic Powers, Con- denser, &c., &c., in Cabinet complete as fig. 907 . . . 880 908 Ditto ditto, one Extra Eye-piece and Objective giving increased Magnifying Power from 425 to 525 Diameters ^with perf ect Definition and Penetration, Extra Apparatus in Cabinet .... 15 15 The Microscopes Nos. 895 to 908 have been constructed to supply instruments of moderate price, but with good workmanship, and solid mechanical arrangements. Larger and more perfect forms of Microscope are described in the following pages. Instruments and Apparatus for Brewers' use will be found described with prices in Sections, Thermometers, page 153; Hygrometers, page 68; Hydrometers and Saccharometers, Glass and Metal, with Excise and Government scales, page 176 ; Polarising Saccharometers, page 278 ; Distilling Apparatus, page 193 ; also an extended list of Chemical Apparatus at the end of this Catalogue. 262 NEGRETTI AND ZAMBBA, HOLBOKN YIADUCT, E.G., NO. 911. 909 Student's Microscope on Brass Stand, with one Eye-piece, one Object Glass giving two powers, Live Box and Brass forceps, packed in Mahogany Cabinet .550 910 Student's Microscope, similar to No. 909, but with two Eye-pieces, two Object Glasses, Condensing Lens on Stand, &c. 770 911 Student's Microscope, similar to No. 910, but with Fine Adjustment to the Body, 2-inch, 1-inch, and i-inch Object Glasses, fig. 911 . . 8 15 912 Larger size Student's Microscope, similar to No. 911, but finished in the best possible manner 13 13 913 Student's Microscope, similar to No. 912, but fitted with Polarising Apparatus, Spot Lens, &c 16 16 45, COENHILL, B.C., AND 122, BEGENT STREET, W., LONDON. 263 NO. 914. 914 Negretti and Zambia's Student's Best Full-sized Monocular Microscope. Brass stand, with Mechanical Stage, Hackwork adjustment and Lengthening Tube to the body, Fine adjustment for the Object Lens, sliding and rotating Object Holder, and Diaphragm to the stage, two eye-pieces, A and B, three Best Achromatic Object Lenses, 1-inch, ^-inch, and -inch, Polar- ising Apparatus, with Selenite Plate, Spot Lens, Camera Lucida, large Condensing Lens on Stand, two Live Boxes or Animalculae Cages, Stage Condenser and Stage Forceps, plain and curved Brass Forceps, Dipping Tubes, Stage G-lasses, &c., &c. ; in Solid polished Mahogany Cabinet, with lock and key, fig. 914 25 264 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.C , 915 Student's Binocular Microscope, fitted with adjustment for width of eyes, a pair of Eye-pieces, 2-inch and 1-inch Object Glasses, Condensing Lens on Stand, Live Box, Forceps, &c., packed in Mahogany Case . 12 12 916 Binocular Microscope, similar to No. 915, but finished in superior manner, and with 1-inch, 1-inch and |-inch Object Glasses (fig. 916) . 18 18 917 Binocular, similar to No. 916, but fitted with Polarising Apparatus, two pairs of Eye-pieces, Spot Lens and Selenite Plate, &c. . . . 22 918 Binocular, similar to No. 917, but with Mechanical Stage, Fine Adjustment, &c 25 920 Binocular, similar to No. 918, but with Larger Stand, Sliding and Rotating object holder, spring side clamp, Clamping Arc for fixing at any angle, extra large Condensing Lens on Stand, Glass Trough, two Stage Plates Fishing Tubes, Frog Plate, &c., in Mahogany Cabinet . 42 45, COBNHILL, E.G., AND 122, BEGfciNT STREET, W., LONDON. 265 No. 921. 21 Binocular Microscope, with Mechanical Stage, having rectangular motions, sliding and rotating object holder, spring clamp slide, revolving Diaphragm, Flat and Concave Mirrors arranged to give an oblique pencil of light, Clamping Arm for fixing the instrument at any angle,. Coarse and Fine Adjustments, two A and two B Eye-pieces, one C Eye-piece, Micrometer Eye-piece, four best achromatic Objectives l^-inch, 1-inch, ^-inch, -inch. Polarising Apparatus, Rotating Selenite, Spot Lens, Stand Condenser, Stage Condenser, Side Reflector, Camera Lucida, Reversible Com- pressorium, Frog Plate, two Live Cages, two Glass Stage Plates, Stage Micrometer, Stage Forceps, Straight and Curved Hand Forceps, and Dipping Tubes in Case, complete in Solid Mahogany Cabinet with Plate Glass door, fig. 921 65 10 266 NEGRETTI AND ZAMBEA, HOLBORN VIADUCT, E.G., 922 Negretti and Zambra's Large Binocular Microscope, with Mechanical Stage, having motion in rectangular directions, Sliding and Rotating Object holder, Spring Slide Clamps, Sub-stage with rectangular motions, revolving diaphragm, flat and concave Mirrors, clamping arm to fix instrument at any angle, coarse and fine adjustments, two A, two B, one C, one D, and one Micrometer Eye-pieces, six Best Achromatic Object Glasses, viz., 3-inch, 1^-inch, 1-inch, |-inch, -inch, and -inch. Polarising Apparatus, Barker's revolving Selenite Stage, Paraboloid, Spot Lens, Stand and Stage Condenser, Side reflector, Brook's double Nose-Piece, Camera Lucida, Reversible Compressorium, Frog Plate, large and small Live Boxes, two Stage Plates, Stage Micrometer, Stage Forceps, straight and curved Forceps, Dipping Tubes in case, fitted in Solid Mahogany Cabinet with Plate Glass door (fig. 922) 90 NEGEETTI AND ZAMBEA, HOLBOBN YIADUCT, E.C., 267 023 Negretti and Zambra Large Binocular Microscope, with graduated rotating Goniometer stage with rectangular motions, graduated rotating Sub-stage, flat and concave Mirrors, clamping arm to fix instrument at any angle, coarse and fine adjustments, two A, two B, one C, one D, one Micrometer and one Kellner's Orthoscopic Eye-pieces, eight best Achromatic Object Glasses, viz., 3-inch, 2-inch, l|-inch, 1-inch, ^-inch, -inch, -inch, ^-inch, three Lieberkuhns, Gillett's Achromatic Condenser, large Paraboloid, large Spot Lens, Stand and Stage Condensers, side Illuminator, Polarising Apparatus, Barker's Revolving Selenite Stage, Brook's double Nose-piece, Lister's Dark Wells, Reversible Compressorium, High Power Compressorium, large and small Live Boxes, Camera Lucida, Stage Forceps, Stage Micrometer, straight and curved Forceps, two Glass Troughs, two Stage Plates, two Dissecting Plates, Frog Plate, three Modifiers, Dipping Tubes in case. Fitted in Solid Mahogany Cabinet for the instrument and flat Case for the apparatus, with draw for containing Mounted Objects, Form of Stand, &c., as fig. 922 . . . 150 924 Extra Large Binocular Microscope, with Goniometer Stage, Diaphragm and seven Eye-pieces, 2 A, 2 B, 2 C, two Orthoscopic Eye-pieces, one D, one E Achromatic Eye-piece, one Centreing Eye-piece, best 4-inch, 3-inch, 2-inch, l^-inch, 1-inch, |-inch, ^-incb, ^-inch, -g-inch, -j^inch Achromatic Objectives, 2-inch, 1^-inch, 1-inch, ^-inch Lieberkuhns in box, Silver Side Reflector, Reversible Compressorium, Best Compressorium, Spring Compressorium, Spring Compressorium for high powers, large, second size, and small Live Boxes, Frog Plate, Brook's Double Nose-piece, Best Screw Micrometer, Field's Ratio Polariscope with Rotating Body Prism, Large Spot Lens, Large Paraboloid, Read's Hemispherical Condenser, Gillett's Achromatic Condenser, Lister's Dark Wells and fittings, Amici's Prism, Micro. Spectroscope, Stage Condenser, Stage Forceps, two pair Brass Forceps, one Curved Bottle Forceps, Stage Micrometer in brass mount in morocco case, Maltwood's Finder in case, two Glass Troughs, one Glass Polyp's Trough, thin front, three Dissecting Plates, two Stage Plates, six Tubes in case, box of : Thin Covering Glasses, three Modifiers in box, Large Stand Condenser with Double Rod, Camera Lucida with Dark Shades, Large Flat Walnut Case for Apparatus, with chased work, and Mahogany Cabinet, with glazed door, for Microscope, and flat Case for the apparatus. 200 No. 924 can be supplied to special order in a Solid Spanish Mahogany- winged Case, with Plate Glass doors; the wings having a series of Drawers, having Porcelain Tablets and numbered Knobs, for holding 1,000 Microscopic Objects lying flat. Price Extra 22 The Microscopes Nos. 922, 923, and 924, are especially suited for Presentation Instruments. 268 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., 925. ENGLISH ACHROMATIC OBJECT GLASSES. BEST QUALITY. Object Glass Angular Aperture Magnifying Power with the various Eye Pieces. Price 8. d. A B G D E F 4 in. 9 degs. 12 16 30 40 62 80 1 10 3 13 18 25 38 56 84 112 2 10 2 15 25 35 52 70 100 140 2 10 H,, 20 30 45 70 105 150 190 2 10 1 n 25 40 63 97 140 220 285 2 10 4 90 95 150 230 320 475 635 4 10 I 100 210 310 520 780 1100 1400 500 i 140 320 510 700 910 1380 1830 4 10 I.,, 140 425 600 900 1200 1830 2400 500 To 160 530 820 1200 2024 2900 4400 15 15 An 170 650 970 1500 3000 4000 5300 18 18 TV" 800 1000 27 Ts 1250 2050 56 10 s > 11 ' The Immersion arrangement to th or th powers, 42s. extra. th, ^th, and ^th, are all of the very highest class of Optical workmanship. 926. SECOND QUALITY. Object /->!-| Angular Magnifying Power with the various Eye Pieces. Price 3 Glass. Aperture A B C D E F 8. cl. 3 in. 10 degs. 18 25 38 56 84 112 1 10 2 ^ 25 35 52 70 100 140 1 10 15 30 45 70 105 150 190 1 10 I 2 ," 16 40 63 97 140 220 285 1 10 f " 55 95 150 230 320 475 635 2 10 4 9) 75 210 310 520 780 1100 1400 2 10 4" 8 120 130 320 425 510 600 700 900 910 1200 1380 1830 1830 2400 5 10 6 10 Those marked (*) have adjustments for covered and uncovered objects, and all the screws are cut to the Standard Gauge of the London Microscopic Society. 927 Sets of Achromatic Object Lenses, for Microscopes of French or German manufacture, combined focus, 1-inch . . . . 1 C Ditto ditto, -inch 150 Ditto ditto, i-mch 1 10 45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 269 928 Field's Differential or Eatio -Micro Polariscope, an instrument for the mathematically-exact application of Polarised light in Microscopical research ; price, with new rotating body prism, packed in mahogany cabinet 17 10 Only adapted for Instruments having Sub-Stages. 929 Improved Micro Spectroscope. Showing two Spectra in the field of view at the same time ; the small prism by means of which the second spectra is produced is made to remove from the field of view when only one spectra is required : this instrument is supplied with two adjustable slits at right angles to each other, with adjustments for regulating the width of slit required, and the eye lens is also furnished with rack and pinion adjustment for focussing the spectra and lines under examination. The stage for holding Sorby's tubes, wedge cells, &c., for showing the spectra bands, are made to remove with the reflecting mirror from the body of the instrument when not required : this spectroscope with achromatic lens to eye-piece, complete as described above, fitted to any microscope 770 For Pocket Microscopes and Hand Magnifiers see pages 223 and 224. APPARATUS, ETC., FOB MICROSCOPES. Each. Each. 930 Eye Pieces, Huyghenian (figs. 930 and 930*) . . . 10 6 15 6 931 Ditto ditto Best A, B, C, and D, E, and F . 16 110 932 Ditto, Erecting, for Dissecting 15 100 933 Ditto Achromatic 1 12 934 Micrometer Eye Pieces 140 935 Kellner's Orthoscopic Eye Pieces, giving larger field . 1 10 936 Ross's Centreing Glass 15 937 Indicator to Eye-piece 066 938 Brook's Double Nose Piece, for rapidly changing the Object Lens or power of a Microscope ... 1 10 940 Stand Condensers, small (fig. 940) 10 6 16 941 Ditto ditto with Large Lens and convenient adjustments (fig. 941) 22s. 1 10 1 16 942 Shadbolt's Parabolic Condensers, in brass mountings . 1 14 2 15 942* Amici's Prisms ....,.,.. 2 10 6 943 Achromatic Condenser, plain 250 944 Ditto ditto Gillet's 700 945 Achromatic Eye Pieces, D 16 946 Ditto ditto E 18 947 Kingsley's Illuminator 3 18 948 Reade's Hemispherical Condenser 220 949 Lieberkuhn, or Cup Reflector . . . 10s. 6d. 16 100 950 Rectangular Prism, for use instead of a mirror . . 1 10 2 10 951 Rainey's Light Modifier 076 952 White Cloud Illuminator ...... 12 6 270 NEGRETTI AND ZAMBEA, HOLBOEN VIADUCT, E.G., FIG. 940. FIG. 961, FIG. 941. 953 Stage Condenser or Side Illuminator, mounted on jointed arm 7s. 6d. 953* Nachet's Prism, for Oblique Illumination 954 Side Speculum Reflector, mounted as ditto (fig. 954) . 954* Dark Wells or Stops, three sizes on jointed holder 954f Micrometer for Stage, divided on glass, ^th and| TD ' 55 th of an inch 955 Maltwood's Finder 956 Polarising Apparatus fitted to Microscope . 957 Tourmalines, mounted to fit eye-tube, price according to quality and size from 958 Selenite, mounted for Stage . . . 959 m Ditto ditto in Brass Mount .... 960 Camera Lucida, Wollaston's, for drawing magnified image, mounted to fit microscope .... 961 Ditto ditto with additional lenses and shades (fig. 961) . 962 Beale's Neutral Tint Reflector (fig. 962) 963 Improved Argand Oil Lamp, adapted for Microscopic purposes (fig. 963) 964 Paraffin Microscopic or Reading Lamps, in various mountings (fig. 964) Each, s. d. 12 6 110 2 10 020 Each. s. d. 116 220 1 12 12 6 10 6 086 3 15 12 2 7 10 1 10 1 10 1 15 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.G. O 271 FIG. 965. FIG. 964*. FIG. 963. Each. s. d. 964* Microscopic Argand Gas Lamp, with Improved illumin- ating lens and chimney, and^the stand conveniently arranged for various purposes connected with pre- paring and mounting microscopic objects. This Lamp can also be used as a Reading Lamp or for Chemical Operations (fig. 964*) Paraffin Microscopic Lamps, with Porcelain Shade, vertical adjustment to both Stand and Shade (fig. 965) Ditto ditto in Polished Pine Cabinet . . Bochett's Microscopic Lamp (Paraffin) Brass Mounted, with Condenser, Reflector, Shade, and universal adjustments ; in Mahogany case . . Porcelain Shade, for Microscopic Lamp Lamp Glasses, for do Forceps, of several forms, for taking up small objects, dissections, &c 2s. 6d. 3 Ditto ditto Curved for Phials . . . .03 Wood Forceps, Page's, for mounting objects Stage Mineral Holder Stage Forceps, with jointed arm, very useful for holding objects while under examination in the microscope (fig. 975) 10 Dissecting Needles, or Needle holders . . . .01 Dissecting Scissors . .03 Ditto ditto Curved Ditto ditto Spring Dissecting Knives . . 02 Each. s. d 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 330 10 6 18 6 330 1 050 066 026 110 12 6 050 066 066 10 6 030 272 KEQRETTI AND ZAMBRA, HOLBOEN VIADUCT, B.C., FIG. 985. FIG. 975. Each. Each. s. d. a. d. 980 Valentine's Dissecting Knives, for cutting thin sections of soft animal substances, &c 17 6 110 981 Three-pronged Forceps, of German Silver, with screw adjustment 17 6 982 Ditto ditto plain mounting .... 15 983 Microscopic Dissecting Instruments, in neat case . .110 2 10 984 A Selection of all the Necessary Materials for Mounting Objects, arranged in a mahogany box .330 440 985 Glass Cell, round, for holding fluids, viewing circulation in plants, polyps, &c. (fig. 985) 016 986 Animalculae Cage or Live Box, for conveniently examining water containing animalculse, living insects, &c. (fig. 986) 5s. 6d. 7 6 10 6 987 Animalculae Box, Yarley's Pattern, with raised centre (fig. 987) 12 6 16 989 990 991 992 993 994 995 FIG. FIG. 987. 15 Compressorium, for similar purposes, where the object requires greater pressure Ditto ditto Best Lever Frog Plate, for holding Frogs, Fish, &c., to exhibit the circulation of the blood Glass Rings, Cells, Circles, Squares, &c., of various sizes and thicknesses, for mounting injections, &c., from per doz. 30 Plate Glass Stage Plates, with Oval or Bound cells per doz. Glass Sides, with ground edges for mounting objects, ol! the best quality, 3-in. by 1-in. . . . per doz. Thin Microscopic Glass, cut in Squares, per oz. Ditto ditto cut in Circles . ...060 1 16 4 4 1 3 10 10 6 12 6 45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 273 FIG. 1010. FIG. 1014. FIG. 1013. 996 Coloured Paper Mountings for Slides, from Is. per dozen. FIG. 997. FIG. 998, Each. s. d. Each. s. d 997 Collector's Pocket Microscope, with two powers and forceps for holding the object, in neat hinged case (fig. 997) ... 10 6 998 Pocket Microscopes or Magnifiers ; for prices, &c., see pages 223, 224 fig. 998. 999 Animalcules Tubes, or Collecting Bottles, fitted with corks, for collecting specimens . . . per doz. 036 1000 Ditto ditto in sets and pocket cases . . . 10 6 15 1001 Sets of 3 Animalculse Fishing Tubes, in case . 026 1002 Ditto 6 ditto ditto 050 1003 Writing Diamonds 10 6 1004 Cutting Ditto 16s. 110 1 10 1005 Instrument for cutting Circles of Thin Glass . 1 10 4 10 1006 Turn Tables for preparing circular Gold Size Cells . 10 6 1007 Section Cutters, for wood, bone, &c 1 10 220 1008 Air Pump for preparing objects (see also Pneumatic Section) 110 1 10 1009 Brass Injecting Syringe for ditto 10 6 1 10 1010 Mounting Apparatus or Compressorium, for preparing Microscopic objects in Canada Balsam, &c. (fig. 1010) 12 6 1011 Canada Balsam per bottle 010 1012 Turpentine 010 1013 Spirit Lamps (fig. 1013) various sizes, see Chemical Section 026 036 1014 Metal Support for Mounting 026 274 NEGRETTI AND ZAMBRA, HOLBORN YIA.DUCT, E.G. Each. Each s. d. s. d. 1015 Gold Size ... per bottle 010 1016 Asphalte Varnish .,010 1017 Damar ditto V . . . ,,016 1018 Glycerine JeUy . ,,010 1019 Deane's Gelatine Medium 020 1020 Farrant's ditto 020 1021 Marine Glue 010 1022 JEther, Acetic Acid, Liquor Potassas, Solution of Chromic Acid, Turpentine, Carmine Solution, Logwood Solution, &c., &c., per bottle, from 010 APPARATUS FOR COLLECTING MICROSCOPIC OBJECTS, &c. 1023 Complete Apparatus for collecting Animalculae, Diatoms, Desmids, &c. &c., consisting of Collecting or Pond Stick, Spring Clip with bottle, Metal Ring for gauze net, Spoon and Weed Knife to screw into collecting stick, Strainer, Drag Hooks, &c 220 1024 Collecting Bottles, clear white glass, with welted necks fitted with corks and turned wood tops Capacity 123 ounces Per doz. 3s. 3s. 6d. 4s. 1025 Set of 6 Collecting Bottles, in japanned tin pocket case 050 1026 Pipettes 003 006 All other Chemical Tests, Reagents, &c., &c., required for Microscopic Mounting supplied to order. SPECTRUM APPARATUS FOR THE MICROSCOPE. 1027 Sorby's Micro-Spectroscope 5 10 1028 Ditto ditto with Rackwork motion to the Eye-piece . 5 15 1029 Ditto Standard Spectrum Scale 110 See also No. 929, page 281. MICROSCOPIC OBJECTS. 1030 A Set of Twenty-four Microscopic Objects, Transparent and Opaque, dry mounted and named ; in a neat box 036 1031 An extensive Assortment of Balsam Mounted Microscopic Objects, of English and French mounting 010 016 These objects consist of insects, parts of insects, such as wings and wing-cases, stings, tongues, eyes, dissections of the trachea and bronchial tubes, antennae, legs, the scales of butterflies and moths, zoophytes, ferns, fuel, mosses, madrepores, sections of recent woods, leaves, petals, and farina of plants, feathers, hairs, exuviae of spiders and aquatic insects, algae or sea weeds, sponges, echinus' spines, shells. 45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 275 Each. Each. s. d. s. d. 1032 Test Objects, Balsam Mounted Podura, Hair of Mouse and Bat, Navicula Hippocampus, &c. . .016 020 1032* Entomological Preparation Various Insects, Acara Parasites, &c., mounted in Canada Balsam, showing the respiratory, digestive, and nervous systems, and their modifications for terrestrial and aquatic habits Is. 016 020 1033 Vegetable Preparations, showing spiral vessels, ducts, tissues, raphides, cells and spores in plants ; sections of wood, seeds, leaves, petals, fungi, &c. . . .016 020 1033* Polarising Objects, consisting of crystalline salts, hoofs, horn, skin, tendon, fish scales, palates of mollusca, vegetable substances, starches, &c 016 020 1034 Anatomical Preparations, Transparent and Opaque, muscular fibre tissues, blood discs, pigment cells, &c. 020 030 1035 Ditto ditto Bacteria, Bacilli, &c., prices various 1036 Sections of Fossil Woods, Exogenous, cut in three directions 10 6 1037 Ditto ditto Endogenous, cut in two directions . 076 1037* Sections of Limestone, Oolite' Flint, containing sponges, fish scales, and fossil infusoria 040 1038 Sections Longitudinal and Traverse, of recent and fossil bones, fossil and recent Teeth, Sections of Flint containing Xanthidium 020 030 1039 Diatomacese : Recent and Fossil, numerous varieties of Navicula, Campylodiscus, Cocconema, Epithemia, Desmidiae, &c., from various parts of the World .016 020 1040 Cabinet of polished Mahogany for containing Microscopic Objects, fitted withjdrawers and divisions 3 3 1041 Cabinet ditto Spanish Mahogany, to hold 1,000 objects 660 1042 Ditto ditto with Plate Glass doors ... 880 1043 Polished Pine Wood Boxes, with trays to hold three dozen objects 046 1044 Ditto ditto for six dozen ditto 10 6 1045 Ditto ditto for six dozen ditto with lock and key 12 6 1046 Mahogany Racks for holding objects, per foot, Is. 1047 Cardboard Boxes, with wood racks, to hold 1 dozen Is., 2 dozen, 2s. 1048 Microscopic Tables, of polished Rosewood, Walnut, or Mahogany, the top covered with leather or cloth .880 10 10 A SPECIAL MEDAL AWARDED TO NEGRETTI AND ZAMBRA FOR MICROSCOPES. Philadelphia International Exhibition, 1876. T 2 276 NEGEETTI AND ZAMBEA, HOLBOEN VIADUCT, E.G., CEOOKES' EADIOMETEE. This Instrument demonstrates the supposed conversion of Light into Mechanical Motion, invented by Mr. William Crookes, F.B.S., and first exhibited by him at the Soiree of the Royal Society, April 7th, 1875, and described by him in the Quarterly Journal of Science, for July, 1875, as follows : " The Instrument which I have called a Radiometer, shown in fig. 1049, consists of four arms, of some light material, suspended on a hard steel point resting in a cup, so that the arms are able to revolve horizontally upon the centre pivot, in the same manner as the arms of Dr. Robinson's Anemometer revolve. To the extremity of each arm is fastened a thin disc of roasted mica or pith, white on one side and lamp-blacked on the other, the black surfaces of all the discs facing the same way. The whole is enclosed in a thin glass globe, which is then exhausted to the highest attainable point and hermetically sealed. " The arms of this Instrument rotate with more or less velocity under the action of radiation, the rapidity of revolution being directly proportional to the intensity of the incident rays. Placed in the Sun, or exposed to the light of burning Magnesium, the rapidity is so great that the separate discs are lost in a circle of light. Exposed FIG 1049 ^0 a Candle 20 inches off another instrument gave one revolution in 182 seconds. With the same Candle placed at a distance of 10 inches off the result is one revolution in 45 seconds ; and at 5 inches off one revolution was given in 11 seconds. Thus it is seen that the mechanical action of radiation is inversely proportional to the square of the distance. At the same distance 2 Candles give exactly double, and 3 Candles give three times, the velocity given by 1 Candle, and so on up to 24 Candles. A small Radiometer was found to revolve at the velocities shown in the following table, when exposed to the radiation of a standard Candle 5 inches off. Time Required for One Revolution. Source of Radiation. Time in Seconds. 1 candle, 5 inches off. behind green glass 40 5 blue 38 5 purple 28 5 orange ., 26 5 yellow 21 5 light red,, 20 " The position of the light in the horizontal plane of the Instrument is of no consequence, provided the distance is not altered ; thus' two Candles, 1 foot off, give the same number of revolutions per second, whether they are side by side or opposite to each other. From this it follows that if the radiometer is brought into a uniformly lighted space it will continue to revolve. " In diffused daylight, the velocity was one revolution in from 1*7 seconds to 2'3 seconds, according to the'intensity of the incident rays. In full Sunshine, at 10 A.M., it revolved once in 0'3 second, and at 2 P.M. once in 0'25 second. " When heat is cut off by allowing the radiation to pass through a thick plate of Alum, the velocity of rotation is somewhat slower." 1049 Crookes' Radiometer, with Black and White Discs (as fig. 1049) on Stand 10 6 Ditto ditto, with Double Vanes Rotating in opposite directions, on Stand . 110 For further details of Preliminary Experiments and Researches, &c., &c., see Pamphlet, Crookes' Radiometer. Price Is. 45, COENHILL, E.G., AND 122, EEGENT STBEET, W., LONDON. 277 |H|: NEGRETTI ZAMBRA. '"';i!|| FIG. 1053*. FIG. 1053. POLARISCOPES AND POLARISING APPARATUS. Each. Each s. d. s. .1. 1050 Tourmaline Polariscope, elementary form two plates of tourmaline arranged in Spring Wire Forceps for holding any crystal to be examined between them, very useful for testing Pebble Lenses in Spectacles . 150 1051 Reflecting Polariscope, Malus's. The Polarising and Analysing bundles are formed of very thin plates of Glass mounted in* brass frames on a metal stand, adjustable at any desired angle. Between these Bundles or Mirrors is a stage for holding Crystals, &c., to be examined, this stage having horizontal movement, with a graduated circle for noting the angle of rotation, &c. ....... 330 1052 Biot's Improved Black Mirror Polariscope. In this instrument Black Glass Mirrors are used instead of the Bundles of Glass, and these Mirrors are fitted with Divided Arcs for adjusting them to any angle. The rotating stage has also a Divided Circle and a spring clip object holder to support the crystals,; &c., under examination. Complete with Tourmaline Plate of Selenite of uniform thickness, Double Image Prism, brass frame for showing polarising structure produced by unequal pressure in a piece of annealed glass, with diaphragm of greyed glass, &c. ; in Cabinet . 7 10 1053 Woodward's Table Polariscope (fig. 1053), for conve- niently illustrating the interesting phenomena of Polarised Light ; fitted either with a Bundle of thin glass or a black mirror. Large and small stage with spring object holder, E/ack-work adjustments to eye-tube, Powers, &c., &c., complete in a Cabinet forming a Stand for the instrument .... 10 10 Woodward's Polariscope can be supplied for use with the Oxy-Hydrogen Microscope, at a slight additional cost. NEGEETTf AND ZAifBKA, HOLBOBN VIADUCT, E.G., FIG. 1055. 1054 Tourmaline Polariscope, a frame, having a revolving disc carrying a series of Crystals, which may be successively brought between the Tourmalines ; each of the latter can be made to revolve in its own plane, and thus place their axes parallel or perpendicular to each other at pleasure, and vary the phenomena of each crystal 4 10 1055 Soleil's Polariscope or Saccharometer, improved by Duboscq, for estimating the value of fluids, &c., with the most recent improvements (fig. 1055) ... 16 1056 Laurent's New Shadow Polarising Saccharometer, having two series of divisions, one for the percentage of Sugar, and the other graduated for general Laboratory Work. Complete with one Gas Burner, fitted with two Jets, three Glass Tubes, &c., &c., mounted on a Bronzed Adjusting Stand Price hi Box 18 1057 Ditto, ditto, of the most complete form, having all recent improvements, Gas Burner with two Jets, four Glass Tubes, &c., (fig. 1057) Price in Box 30 This Saccharometer is of much greater accuracy than previous arrangements, and is now adopted by the French Government. In ordering the Saccharometer the approximate pressure of Gas to be used should be stated. 1058 Eolipyle. If Gas is not available, or if the pressure be feeble and irregular, it is advisable to use the Eolipyle, burning Spirit instead of Gas. (fig. 1058) Price . .330 Instructions for use are sent with each instrument. 1059 Double Image Prism, Selenite Disc of equal thickness, and Three-hole Slider for ditto, for showing the production of white light by the union of the complementary colours 110 1060 Unannealed Glass, various shapes, for showing the permanent polarising structure of glass that has been uniformly heated and suddenly cooled ... 056 45, CORNHILL, B.C., AND 122, EEGENT STREET, W., LONDON. 279 280 NEGRETTI AND ZAMBEA, HOLBORN VIADUCT, E.G., 1061 1062 1063 1064 1065 1066 1067 Brass Frame, for showing the transient polarising Each. structure communicated by Pressure to a piece of s> annealed glass Apparatus, for showing the same effect by the unequal application of Heat , Polarising Eye-piece of thin glass, in brass mounb Nicol's Single Image Calc-Spar Prism . . 12s., 15s, 1 10 Nicol's Double Image Prism of Calc-Spar . Tourmalines of various sizes and colours . . 10s. 12 6 Thin Selenite Plates of equal and unequal thickness, developing uniform or various colours Each. a. d. 10 8 5 2 2 18 1 10 030 040 123 FIG. 1068. 1068 Selenite Designs are formed of pieces of Selenite different in thickness arranged in a variety of forms, such as cubes or stars, for showing the beautiful colours produced by the varying thickness of the film of Selenite. each 10s. 6d. 1 10 1069 Design in Selenite, with motto on ribbon, "Forget-me- not _i (fig. 1068) 018 1070 Thistle, in Selenite, with motto on coloured ribbon, " Dinna Forget "3 18 1071 Tulip in Selenite 2 . 18 1072 Selenite Design of a Gothic Church Window . 44 1073 Circular Plate of Selenite, ground Concave, to develop the colours in rings ....... 16 1074 Rhombs of Iceland or Double Refracting Spar, to show the multiplication of images afforded by peculiar structure of the crystal . . 5s. 6d., 7s. 6d. 10 6 1 10 1075 Plates of Quartz, Arragonite, Amethyst, Topaz, Calc-Spar, Borax, Nitre, Beryl, Bochelle Salts, Sugar, Bi-chromate of Potass, Sulphate of Iron, cut at right angles to their axes, for exhibiting coloured rings, compound figures, bars and cross-bars, screws, and crosses, &c. 10s. 6d. 110 200 1076 Sliders, with fish fins and scales, laminae of human cuticle, sections of teeth, bones, hoofs, horns, and tendon, various chemical salts and vegetable productions, &c., preserved in Canada Balsam, to exhibit their polarising structure ; adapted for the Table Polariscope . .016 026 1076* Microscopic Quartz Lenses, 2 10s. to 6 10s., according to Diameter. GLASS, QUARTZ, AND OTHER PRISMS, AND EVERY DESCRIPTION OF APPARATUS OR OBJECTS PREPARED FOR EXPERIMENT WITH POLARISED LIGHT. Polarising Apparatus fitted to Table or Lime Light Microscopes. Polarisation of Light. By ~W. Spottiswoode, L.L.D., late President of the .Royal Society, &c. New Edition with numerous Illustrations. Crown 8vo. 3s. 6d. 45, CORNHILL, E.G., AND 122, EEGENT STREET, W., LONDON. 281 SPECTRUM APPARATUS. FIG. 1078. 1077 Negretti & Zambia's Pocket Spectroscope, in Brass Mountings, plain Slit 1078 Pocket Spectroscope, for observing the Rain Band, with adjustable slit, will show many of Fraiinhofer's lines (fig. 1078) 1079 Direct Vision Rain-Band Spectroscope, larger size, of very great dispersive power ..... 1080 Table Spectrum Apparatus (or Spectroscope), simple form for Chemical Analysis a. d. EacR. s. d. 1 15 2 10 550 7 10 FIG. 1081. 1081 Spectroscope, Duboscq's arrangement, one Prism, horizontal Telescope, and transparent Micrometer, Gas Burner, and forceps; on adjusting Stand, (as fig. 1081) 16 10 0. 1082 Table Spectroscope, with one Prism, Eye-piece, and divided Circle 10 10 1083 Ditto ditto, with Two Prisms .... 17 10 1084 Ditto ditto, with Four Prisms .... 35 1085 Table Spectroscope, with two Prisms, high and low Power, divided Circle, Comparison Prism, Micro Scale, two Eye-pieces in Box 14 282 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, B.C., Each. a. d. 220 15 Each. s. d. 330 110 1086 Prisms of Glass, of various Density . .110 1087 Bisulphide of Carbon Prisms 1088 Spring Stage, for studying the absorption Spectra of coloured glasses 12 1089 Gladstone's Wedge, for exhibiting the absorption spectra 1 12 1090 9-inch Glass Tube, with Stop-Cock, for examining the dark lines seen in gases and vapours .... 12 6 1091 A Divided Tube, with two compartments and two flasks, connectors, stop-cock &c., for exhibiting the increase of dark lines with increased temperature and length of vapour 220 Bunsen's Steatite Burner, with Copper Cone, mounted on a stand (M fig. 1081) 12 6 Spectroscope Forceps (or Pincettes), on an adjusting support (N fig. 1081) 11 Bock Salt Prisms and Lenses, Quartz and Iceland Spar Lenses or Prisms 1092 1093 1094 supplied to order. FIG. 1096. FIG. 1095. PORTABLE OXY-HYDROGEN GAS POLARISCOPE. 1095 Complete with Apparatus for producing and Purifying the Gases. Full size Gas Bags and Pressure Boards. Flexible Conducting Tubes. Brass Connec- tions, &c., &c. Best Lime Clock. Mahogany Portable Tripod Stand, as shown in fig. 1095 ... 34 1096 Ditto ditto with Microscope (fig. 1096) . . 42 1097 Professor Roscoe's Lectures on Spectrum Analysis (Third Edition), largely Illustrated. Six Lectures on Spectrum Analysis and its Applications, delivered before the Society of Apothecaries. Price 1 Is. * See Section Electric Light for Lantern Spectrum Apparatus. SURVEYING INSTRUMENTS, THEODOLITES, LEVELS, C1RCUMFE RENTERS, COMPASSES, ETC. Negretti and Zambia's Improved 7-inch Azimuth and Altitude Instrument, Or Transit Theodolite (Fig. 1107). See page 285. The construction and accuracy of the instruments enumerated in this section being of the first importance, Messrs. NEGRETTI AND ZAMBBA devote special atten- tion to this particular branch of manufacture, to insure the most perfect finish and precision that can be obtained by modern improvements in machinery, dividing engines, &c. 284 NEGRETTI AND 2AMBRA, HOLBORN VIADUCT, E.G., FIG. 1100. THEODOLITES. 1098 3-inch Theodolite, divided on Silver, with Telescope and tripod stand ......... 1099 4-inch Theodolite, divided on Silver, with three tangent screws, tripod staff, &c., complete .... 1100 5-inch Best Theodolite, divided on Silver, reading to 1 minute, with three tangent screws, rack work adjust- ment to telescope, tripod staff, complete ; with stout mahogany box, improved screwed packings, strong brass handle and loops adapted for a strap (fig. 1100) 1101 6-inch Best Theodolite, divided on Silver, reading to 20 seconds ........ 1102 7-inch ditto ditto to 10 seconds 1102* 3-inch Transit Theodolite with Tripod Staff 1103 4-inch ditto ditto reading to 1 minute 1103* 5 -inch ditto ditto best, divided on Silver, reading to 1 minute, with Diagonal Eye Piece (fig. 1103*). The tangent and clamping adjustments are of the most approved construction . 1104 5-inch ditto ditto divided on Silver, reading to 1 minute, complete with Illuminated Axis, Lamp, and other Astronomical Appendages .... ... Each s. d. 18 18 21 24 31 10 35 10 21 25 29 45, CORNHILL, E.C., A.ND 122, REGENT STREET, W., LONDON. 285 FIG. 1103*. FIG. 1114. Each. s. d. 1105 Transit Theodolite, 6-inch, best, divided on Silver, reading to 20 seconds 36 1106 Ditto r ditto, 6-inch, reading 'to 10 seconds, with Astronomical Appendages ....... 41 1 107 Ditto ditto, 7-inch or Alt-Azimuth and Altitude Instrument The vertical and horizontal circles are divided on Silver, reading to 10 seconds, improved magnify- ing readers to the divided circles, inverting erecting and diagonal eye-pieces, tangent screw adjustment levels, locking'plates, with tripod stand and Mahogany Cabinet for the instrument, with lock and key (fig. 1107) . . . . 48 10 1108 Alt-Azimuth and Altitude Instrument, 8-inch Illuminated Axis, with Lamp, &c., complete as above 56 1109 Ditto ditto 10-inch, with ditto 90 1110 Ditto ditto 10-inch with Micrometer to Declination Circle 95 1111 Ditto ditto, 12 -inch, with Ditto 110 1112 Ditto ditto, 12 inch, with Micrometer to Declination Circle .120 1113 Transit Theodolite, 5-inch, as specially made for the War Office, with Solid Vertical Circle and covered Arcs, having three horizontal and two Yertical Yerniers, fitted on Locking Plate in stout Mahogany Box, and with firm Tripod Stand 30 1114 Everest's Theodolites, 4-inch, divided on Silver reading to 30 seconds, with triangular locking plate (fig. 1114) with Tripod Stand . . , 22 1115 Ditto ditto, 5-inch ditto 20 seconds . . . . . 26 10 1116 Ditto ditto, 6-inch, reading to 20 seconds 33 1117 Ditto ditto, 7-inch, reading to 10 seconds 37 1118 Ditto ditto, 10-inch, reading to 10 seconds, with open braced stand, lantern, and axis level 63 Instruments more finely divided, 21s. extra. Fcr description and prices of larger Transit instruments, &c., &c., see Section Astronomical Instruments. 286 NEORETTI AND ZAMBEA, HOLBOKT? YIADUCT, E.G., FIG. 1120. SURVEYING AND DRAINAGE LEVELS: 1119 10-inch best Dumpy or Gravatt's Level, with Achromatic Telescope and rackwork adjustment, divided Silver Ring Compass, mirror and cross Level, strong brass parallel plates, with mahogany tripod staff, .and case .. 13 13 1120 12-inch ditto (fig. 1120) ... 14 14 1121 14-inch ditto ditto ... 16 16 1122 18-inch ditto ditto ... 18 18 1123 24-inch ditto ditto . 22 Dumpy or Gravatt's Levels, without Compasses : 1124 10-inch ditto ditto ... 12 10 1125 12-inch ditto ditto ... 13 10 1126 14-inch ditto ditto 15 10 FIG. 1127. FIG. 1130. 1127 1128 1129 Best Y Level, with 12-inch Achromatic Telescope and rackwork adjustment, Compass, tangent screw adjustment, parallel plates, in case, with tripod staff (fig. 1127) 17 17 Best Y Level, with 18-inch Telescope .... 18 18 Ditto ditto, with 24-inch Telescope .... 22 45, COENHILL, E.G., AND 122, REGEN1 STREET, W., LONDON. 287 1130 Negretti and Zambra's Improved Ordnance Pattern 15-inch Dumpy Y Level, with reversing and adjusting Y's to telescope, divided Level, Silver ring Compass, Tangent Screw and Clamp on limb, parallel plates, mahogany tripod stand and Box with strap (fig. 1130). 18 18 Ditto ditto 24-inch 22 Theodolites and Levels mounted with improved Locking Plates, as fig. 1114, at about 35s. to 50s. extra charge, according to the size of the instrument. 1131 Solid Leather Cases for Theodolites, with Straps, 35s. 200 250 FIG. 1135. FIG. 1132. FIG. 1134. Each s. d. Each s. d. 1132 Drainage Level, of Brass, with plain sights, ball-and- socket joint (fig. 1132) . . . ... . . 1 15 2 10 1132* Ditto ditto with Tripod Stand : 330 1133 Improved Drainage Level, with adjustment to the sights, ball-and-socket joint, and tripod stand . 440 1133* 4-inch Pocket Spirit Level, or Clinometer, brass frame, with sights and graduated arc for determining the inclination of strata, &c., with socket for staff, in mahogany box (see also Inclinometer) . . . 3 10 1134 Drainage Level, Ordnance Pattern, best mounted, with plain sights, spring adjustments to level, in mahogany box (fig. 1134) with tripod stand 550 288 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., FIG. 1136. 1135 8-inch Drainage Level, with rackwork adjusting Telescope, parallel plates, in mahogany case and tripod stand without Compass (fig. 1135) 660 1136 8-inch Drainage Level, with rackwork adjusting Telescope, with Compass, Cross Level, parallel plates, in mahogany case and tripod stand (fig. 1136) 880 HAND LEVELS, FOB BUILDERS, ENGINEERS, ETC. 1136* Spirit Levels, mounted in polished mahogany frames, with brass top (fig. 1136) : Length inches . 4. 5. 6. 7. 8. 9. 10. 12. Price . . 2s. 6d. 3s. 3s. 6d. 4s. 4s. 6d. 5s. 5s. 6d. 6s. 1137 Ditto ditto Brass-tipped at bottom. Superior finish. Length inches ... 6. 8. 10. 12. Price .... 4s. 6d. 5s. 6d. 6s. 6d. 7s. 6d. 1138 Ditto ditto Brass-plated at Bottom 5s. 6d. 6s. 6d. 8s. 6d. 10s. 6d. FIG. 1136. FIG. 1141. FIG. 1140. 1139 Spirit Levels, rosewood frames, and German silver mountings : Length inches ... 6. 8. 10. 12. 18. Price . . . .6s. 6d. 7s. 6d. 10s. 6d. 12s. 6d. 16s. 6d. 1140 Spirit Levels, plain Brass mountings (fig. 1140) : Length inches 4. 5. 6. 8. 10. 12. Price .... 2s. 2s. 6d. 3s. 6d. 5s. 7s. 6d. 10s 1141 Spirit Levels, Brass mountings, with adjusting screws and best ground tubes (fig. 1141) : Length inches 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. Price . . 6s. 8s. 10s. 12s. 14s. 16s. 18s. 20s. 22s. 24s. 'If with divided tubes, extra. 45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 289 FIG. 1142. i ECKHOLD'S PATENT OMNIMETER. 1142 This important Surveying Instrument, as shown fig. 1142, measures distances and altitudes with accuracy and great economy of time, it accomplishes the work of Theodolite, Level and Chain, and can be used as a Transit Theodolite. Eckhold's Patent Omnimeter, 5-inch, reading to one minute . . 45 Ditto ditto 6-inch, reading to 20 seconds . . . 50 1143 Taochiometer, 5-inch, complete in Stout Mahogany Box . . 36 Ditto ditto 6-inch 40 Printed instructions for use supplied with each instrument. Each. Each. s. d. s. d. 1144 Spirit Level Tubes, plain, marked and warranted, per inch 003 1145 Ditto ditto ditto best ground . 006 1146 Ditto ditto ditto best ground and graduated 006 1147 American Universal Hand Level, for levelling floors, ceilings, or walls 16 1148 Circular Pocket Spirit Level (fig. 1148) .... 066 290 NEGBETTI AND ZA.MBEA, HOLBDRN VIADUCT, E.G., 1149 Under-ground Theodolite for Mining, Surveying, Levelling, or Military Service (fig 1149). Combining in one instrument, the conveniences of a Y or Dumpy Level, Circumferenter, and a Theodolite. On the top of the vertical axis of the instrument is a Compass with divided ring reading by verniers. On two sides of this compass are Spirit Levels with the usual adjustments for Azimuth observations. Attached to the limb of the instrument is a vertical divided circle, upon which is a Telescope with Rackwork adjustment mounted in reversing and adjusting Ts. A Spirit Level is placed upon the Telescope similar to a Theodolite. Vertical angles are obtained and read off on the vertical divided circle by two arms and a vernier scale attached to the axis of the Telescope. The Telescope has cross wires in the Eye Tube. Clamps and tangent screws are attached to the horizontal and vertical movements. Tripod Stand and mahogany box for the instrument Price . 22 Plain Sights to fit on the Compass box or Telescope, Astronomical and Diagonal Eye Pieces, Dark Glass Caps for Sun observations, supplied to order at an extra cost. CIRCUMFERENTERS, OR MINER'S DIALS, CROSS SIGHTS, ETC. s. d. 1150 Circumferenter, or Miner's Dial, 4-inch Ordnance pattern, divided and figured on raised rim to 360, and also the quarters figured below to 90, folding sights, ball-and-socket joint with clamping screws, bar needle and agate centre, the dial lettered the same as a Theodolite, jointed legs. In 2 cases for compass and stand . . . .770 1151 Ditto ditto, 5-inch, with Cross Levels 880 1152 Circumferenter, 5 -inch, with rackwork adjustment and vernier to dial, bar needle, folding sights, ball-and-socket joint, divided cover for vertical angles, jointed legs, complete in two cases . . . . .990 1153 Circumferenter, 6-inch, with rackwork adjustment and vernier to dial, bar needle, folding sights, divided cover for hypo and base, cross levels, with tripod staff, jointed extra points for use at half length, and ball-and- socket joint with plummet, &c., in two cases complete (fig. 1153) 12 12 45, CORNHILL, E.G., AND 122, KEGENT STEEET, W., LONDON. 291 1154 FIG. 1153. FIG. 1148. FIG. 1154. Circumferenter, 6 -inch, or Hedley's inclining dial, improved form, folding sights, two spirit levels, bar needle with agate centre, rack adjustment to dial, two verniers reading to three minutes of a degree, tangent screw adjustment, divided arc for hypo and base, with 'plain sights, complete with ball-and-socket stand, joint legs for use at half length, extra points, plummet, &c., &c., in case complete (fig. 1154) . . . .17 17 Circumferenter, Hedley's Improved, with Telescope, parallel plates 25 1155 Circumferenter, Lean's 6-inch, improved, with Telescope, for surface surveying, centre quadrant, with level, shifting sights ; vernier reading to two minutes, bar needle, cross levels, rackwork adjustments, arc divided on one side 90 each way and on reverse for hypo and base, jointed stand with extra points, &c. fig. 1155 18 18 17 2 292 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, B.C., FIG. 1156. FIG. 1157*. 1156 Graphometers or Surveyor's Dials, 7i-mch divided circles, folding sights, level and bar needle and circular spirit compass, ball-and-socket tripod stand, &o. In a mahogany box (fig. 1156) Price . . . 16 16 1157 Miner's Compass, 4-inch, with folding sights in mahogany case 1 10 2 10 1157* Ditto ditto, with Spirit Levels, &c., mahogany box (fig. 1157) 2 10 300 1 158 Pocket Mining Compass, plain, with Sights, round brass box, bar needle, and stop (fig. 1158) .... 16 1159 Ditto ditto, in round gilt metal case, with bar needle, and stop (fig. 1159) without sights . . . 15s. 18 150 See also Pocket Compasses. FIG. 1160. FIG. 1166. 1160 1161 1162 1163 1164 1165 Surveyor's Cross, octagonal form (fig. 1160) . Ditto ditto, with Compass Ditto ditto (or Pantometre), with movable head and Divided Circle and Compass (fig. 1162) of the best construction Ditto ditto, with Tripod Stand, with ball-and-socket joint Optical Squares, for showing right angles . Ditto ditto, with adjustment in case .... FIG. 1162. Each. s. d. 10 6 Each. s. c 12 1 5 i 10 10 1 16 45, CORNHILL, E.G., AND 122, BEGENT STREET, W., LONDON. 293 FIG. 1174. FIG. 1170. PRISMATIC MILITARY SURVEYING COMPASSES. 1166 Prismatic Compass (Kater's), plain sights and Card dial (fig. 1166) 2-inch, 30s. 2^-inch, 42s. 3-incli, 50s. 1167 Prismatic Compass, 3-inch diameter, with Shades and Mirror, Card dial, in Leather Sling Case 330 1168 Ditto ditto, with engine divided Silver or Aluminium ring and Case 3 10 1169 Ditto ditto, best, 4-inch with Sun Shades, Card Dial and Case .440 FIG. 1170.* 1170 Prismatic Compass, 4-inch best engine divided Silver or Aluminium ring, with Sun Shades and Azimuth Glass, with Case (fig. 1170) 550 1170* Combined Altitude Instrument and Prismatic Compass. Best mounted, with Aluminium divided Ring, in Leather Case with Straps (fig. 1170*) 6 10 294 NEGRETTI AND ZAMBEA, HOLBOEN YJADUCT, E.G., s. d. s. d. 1171 Leather Case and Strap for Prismatic Compass . . 7 6 10 6 1172 Stand for Prismatic Compass, best mounted, Ordnance pattern, with ball-and-socket joint . . . . . . . 1 16 1173 Ditto ditto, plain horizontal movement 180 1174 ' Hutchinson's Prismatic Compass, 3-inch, in Leather Sling Case (fig. 1174) 2 10 1175 Tripod Stand for Prismatic Compass, with ball-and-socket movement . . 1 12 FIG. 1177. FIG. 1177* FIG. 1158. 1177 1178 1179 1 16 Improved Telescopic Prismatic Compass (figs. 1177, 1177*). By it both Vertical and Horizontal Angles can be taken with speed and accuracy Price in Mahogany Box 12 12 Tripod Stand for ditto with ball-and-socket movement suited for either of above Compasses ........ See also Section Pocket Compasses. Standard Mountain or Surveying Barometer (fig. 1179), on Fprtin's principle, is more portable, and less liable to derangement than ordinary Mountain Baro- meters. The arrangement of the flexible leather cistern is so simple, that should the mercury become oxidized, it can be quickly removed, cleaned, and returned to the cistern without fear of affecting the correctness of the indications. The vernier reads to *002 of an inch, and the whole instrument is arranged in a compact and convenient form for safety in travelling, and obtaining the most accurate Altitude measurements. Price, including Tripod Stand (as fig. 1179, or fig. 12, page 13) and stout Leather Travelling Case for the Barometer, &c ........ 10 10 ' See also pagv 10, Meteorological Instruments. 45, CORNHILL, B.C., AND 122, REGENT STBEET, W., LONDOX. 295 FIG. 1179. ANEROID BAROMETERS FOR MEASURING ALTITUDES OR SURVEYING. 1180 Owing to the inconvenient size of Mercurial Standard Barometers, and also from the great risk of breakage in transit, it often occurs that their use has been abandoned by surveyors where otherwise they would have been invaluable for strict altitude measurements. This difficulty is almost entirely overcome by the use of Negretti and Zambra's Altitude and Surveying Aneroid Barometers. These instruments are now constructed with such precision that very small elevations may be ascertained with great exacti- tude. The scale of the altitude aneroid is laid off by actual experiment in a vacuum chamber, the readings being noted both backwards and forwards, such readings being repeated at long intervals, and the observed differences corrected, before finally dividing the scale on the dial. Several tests are also applied to the instrument in order to compensate for errors arising from varying extremes of temperatures. Where it can be conveniently carried, Negretti and Zambra would in all cases recommend their full-sized Altitude Aneroid (fig. 1180) for observers' use ; as from the large diameter of the divided circle, exceedingly minute movements of the index hand may be seen with ease. 296 ITEGRETTI AND ZAMBRA, HOLBORN YIADUCT, E.C., FIG. 1180. FIG. 1184. Should it be that the large Aneroid cannot be carried, Negretti and Zambra can with confidence advise the use of their Watch-sized Aneroids with altitude scales. The exact size of these instruments is shown at page 19. A large number of such small Aneroids having been made by Messrs. N". and Z., and reports received of (their wonderfully 'accurate performance in all parts of the world, warrant N. and Z. in giving the strongest recommendation to them. At page 3 and 26 will be found instructions for measuring heights by the Aneroid, and comparative tables of the French and English scales. A copy of Professor Airy's Altitude Tables supplied with each instrument. 1180 Negretti and Zambia's full range Altitude and Surveying Aneroid Barometer (Orometer), Compensated for temperature, the Scale divided to Inches and Hundredths or Millimetres, with Altitude Scale to 20,000 feet, or about 15 inches of the barometer scale (fig. 1180) in hinged leather case ....... 880 Solid leather case with Sling strap for Ditto ..... 12 6 1181 Pocket Aneroid Barometer, with Altitude Scales to 5,000 feet, moderate elevations ; see ante, page 29 (fig. 24) . . . .550 1182 Watch-sized Pocket Aneroid Barometers, Compensated with Altitude scale to 10,000 feet; see ante, page 24 (fig. 26) . .550 Ditto ditto, to 20,000 feet ........ 660 Ditto ditto, to ditto in Stout Silver case . . .770 Aneroid Barometers with adjusting altitude scales 10s. each extra. 1183 Anemometer, Pocket, Biram's, and Lown's, for registering the velocity of currents of air in mines,- air shafts, drains, &c., &c. For full description and instructions for use, see pages 100 to 103. 4-inch size, 2 10s. ; 2^-inch . . . .220440 1184 Surveyor's Pocket Compass, with Bar Needle or Singer's Card Dial, in Silver Watch Case (fig. 1184) .... 2 10s. 330 See also Section Pocket Compasses. 45, CORNHILL, E.U., AND 122, REGENT STREET, W., LONDON. 297 FIG. 1185. 1185 Perambulator, for measuring the length of roads, streets, &c., consists of an accurately framed Mahogany Wheel, Brass Clamped, the circumference of which is carefully ascertained ; the axis of this Wheel is connected by a series of toothed wheels and pinions to a dial, upon which the number of revolutions of the Wheel are recorded. The divisions upon the dial are English^ Measures ; but any Foreign scale can be substituted to order. Price, Best mounted and finished (fig. 1185) . . . 16 16 FIG. 1186. FIG. 1190. 1186 1187 Trocheameter, Negretti and Zambra's Improved construction for registering the revolutions of a Carriage Wheel and by this ascertaining distances travelled ; it is also applicable for counting the revolutions of fly wheels, paddle wheels, &c., up to 10,000 revolutions, or nearly 23 miles distance, travelled by a coach wheel of 12 feet circumference. These numbers can be repeated by re- setting the instrument, which is very easily done, by removing a nut, and turning back the divided wheels to the point. The Trocheameter is contained in a strong case, with a leather strap for attaching it to the wheel, &c. (fig. 1186) . 330 The Dipleidescope.f A Pocket instrument for obtaining the Correct Time with great facility, by observing the Transit of the Sun across the Meridian * best form 10 10 t See also N. & Z's. Improved Transit Instruments, page 254. 298 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., FIG. 1187. FIG. 1187*. 1187 Pedometer or Watch for Recording and Measuring the distance travelled by a Pedestrian. This little instrument is generally carried in the waistcoat pocket or in the fob, or else attached to a belt or to a button ; the hook attached to the ring must be so fastened to the slit of the pocket or elsewhere that the instrument be always in a Vertical Position. It never requires any winding up, the first step of the Pedestrian sets the works in motion ; they continue to act as long as he moves, and stop when he stops. The dial is divided into twelve divisions, which represent so many Miles, but can be adapted to record Kilometres or any other measure of distance. The Pedometer is corrected by means of an adjusting screw, which is square -headed, so as to be turned by a watchkey ; all that is necessary to do is to walk a mile, and then observe the position of the index hand upon the dial ; the regulator is then turned to the left for Slow, or to the right for Fast, until one division on the dial represents exactly the measure of distance chosen, Mile or Kilometre, &c. This of course will depend upon the length of stride of each individual, and must be regulated accord- ingly. The dots between the figures represent Quarter miles. When about to start, the Index Hand should be placed at Zero, by moving it either backwards or forwards with the finger. If the Pedometer is not required to act, it should be carried with the Pendant ring downwards. FIG. 1187 exhibits the dial or face of the Pedometer, and fig. 1187*, the interior and movement of the instrument. Price, in Stout Silver with case . 2 15 Ditto ditto Price, in Nickel Plated with case . 220 Ditto ditto Price, in German Silver with case 110 1188 Passometer or Step Measurer, is a similar sized instrument to the Pedometer, arranged to record the number of paces or steps taken by the wearer. These are indicated on the face of the instrument by a small circle (similar to the seconds dial of an ordinary watch) up to 50, and then on the large dial by a series of divisions, each equally 50 paces up to 2,500 ; the readings on the dial are continuous as in the Pedometer. Price, in Stout Silver Case . .550 1189 Chronograph. Without stopping the movement of the watch the long seconds' hand of this instrument records on the Dial the interval between two given events, with unfailing accuracy. Price, in Gold Case, 60 guineas ; Silver Case, 45 guineas ; or to go for two hours only, Gold, 20, Silver 12 12s. 45, CORNHILL B.C., AND 122* REGENT STREET, W., LONDON-. 290 Fm. 1197. FIG. 1201. 1190 Current Meter, for ascertaining the tidal rate or flow of streams or rivers, in Miles, Furlongs, and Feet ; the amount of Water delivered per hour in Cubic Gallons and inches ; and the Dynamic force of the Current. This instrument can also be .used. as a Log, to determine the rate of a ship's speed. The scales on the'divided wheels are laid off by careful experiment (fig. 1190). Price in mahogany box . . . .660 770 1191 4-inch Pocket Inclinometer, Brass mounted, with Sights and Graduated Arc for determining the inclination of strata, &c., with socket for staff ; in mahogany box (fig. 1191) , 3 10 FIG. 1191. 1192 Clinometer or Inclinometer, 12-inch, plain boxwood, with divided semi-circle and plumb, for ascertaining the inclination of roads, drains, strata, &c., in a rough way. The divisions on the arc show degrees and inches per yard ; it has also an inclination scale. Price, in pull-off case 16 6 1193 Clinometer, 12-inch boxwood, brass jointed, with divided arc and inclination scale, forming a pocket rule . ... 1 1 1194 Clinometer, 6-inch, plain-jointed, without Sights or Compass ......... 110 1195 Clinometer, 6-inch, with Spirit Level, Magnetic Compass, and Inclination Scale 1 18 220 1196 Ditto ditto, Bar Needle Compass, and two levels . . 2 10 1197 Ditto ditto, with best Bar Needle and Agate Centre Compass in the joint (fig. 1197) ..... 330 The inclination scale placed upon these Clinometers, &c., gives the value of any angle, as follows , The angle having been ascertained from the divided arc upon the instrument, refer to that degree in the column marked Angle, and opposite, in another column, will be found the rise or fall in any given measured distance ; for instance, say the degree shown on the divided arc is 18, opposite to this number on the scale is 3, this indicating one part rise or fall in three, or one mile in three miles, one t'oot in three feet, &c. 300 NEGRETTI AND ZAMBBA, HOLBOEN VIADUCT, E.G./ 1198 Geological Compass, for ascertaining the dip or inclination of strata, hills, &c., with index, in degrees and inches per yard, in mahogany box, 4| inches square ...;., 10 6 1199 Ditto ditto, 3 inches 076 1200 Ditto ditto, 2| inches . 070 1198io 1200, if with best Bar Needles, 2s. 6d. each extra. 1201 Geological Compass, Brass mounted, with best Bar Needle and leather case (fig. 1201) . .30s. 42s. 2 10 3 10 FIG. 1202. 1202 Pocket Alt-Azimuth Instrument, improved by Francis Galton, Esq., F.RS., is a combined Compass and Pendulum or Wheel Clinometer. A most convenient and portable instrument for obtaining, in a ready manner, Angles, Levels,' &c., similar to No. 1170*. The Telescope renders this instrument available for observing, at a considerable distance from the Station, either Magnetic Bearings, Horizontal or Yertical Angles, &c.. &c. Price in case, as fig. 1202 .... 660 Pocket Alt-Azimuth without Telescope 5 10 Our woodcut shows the Clinometer side of the instrument, with the Telescope as drawn out for use 1202* Hydroscope or Telemeter, a simple apparatus constructed by Negretti and Zambra for the Government Ordnance- Department for use in Marine Forts, to estimate the distance of vessels and other objects . 500 45, COBNHILL, E.G., AND 122, EEGENT STEEET, W., LONDON 301 FIG. 1203. 1203 Abney's Contouring Reflecting Level or Pocket Altimeter. Improved form with divided arc to show gradients, &c., (Fig. 1203). Price in case . 220 Fig. 1202 and Fig. 1203 are very nearly the actual size of the instruments described above. FIG. 1215. FIG. 1209. FIG. 1216. 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 LAND MEASURING CHAINS, TAPE MEASURES, ETC. Land Chain, Iron, 50 feet, and 10 Arrows Ditto, ditto, 100 feet, and 10 Arrows .... Land Chain, 100 feet, best Steel Wire with ditto . Gunter's Iron Measuring Chain, sixty-six feet, or four poles in length. Light wire ..... Ditto dito, Stouter, Galvanised Gunter's Iron Measuring Chain, lest quality, Steel Wire, with three sawed oval rings between each link, and swivel in middle, and stout Brass swivel handles and marks Galvanized (fig. 1209) Twenty-metre Chains, Centimetre links, best make Arrows, set of Ten Steel wire, Pointed and Numbered for Ditto, 15 inches long and If -inch eye . Standard Chain, 50 -feet, best stout Steel Wire . Ditto ditto 66-feet Ditto ditto 100-feet 11 14 1 2 12 15 18 6 18 6 020 4 10 660 8 10 Q 302 NEGEETTI AND ZAMBEA, HOLBOEN VIADUCT. E.G., 1214 Measuring Tapes, common, Leather cases : Length . : 33-feet. 50-feet. 66-feet. 100-feet. Price . 4s. 5s. 6d. 6s. 6d. 10s. 6d. 1215 Measuring Tapes, in japanned Leather eases, with folding handle, rollers, &c.:-(fig. 1215.) Length . . 33-feet. 50-feet. 66-feet. 33-feet. 5s. 6d. 6s. 6d. 100-feet. 11s. Fig. 1225. 1219 1220 1221 12 Price . 1216 Best Measuring Tapes, in Best Patent Solid Leather Cases, Black |or Brown, folding handles, rollers, scale marked on one side only (fig. 1216.) Length . 33-feet. 40-feet. 50-feet. 66-feet. 100-feet. Price . 8s. 9s. 10s. 6d. 11s. 6d. 15s. 1217 Best Measuring Tapes, as No. 1216, with English and Metre Scales, or English and Varas. (fig. ). Length . 10-feet. 15-feet. 20-feet. 25 30-Metres. Price . 8s. 6d. 9s. 6d. 12s. 6d. 14s. . 16s. 6d. 1218 Patent Elastic Steel Tapes, leather case, flush handles, marked on both sides 33-feet, or 2 poles, 24s. 50-feet 1 15 66-feet, or 4 poles, 45s. 100-feet 3 3 Patent Pocket Spring Measuring Tapes, in Brass Case, (fig. 1219) 3-feet 2s. 6d., 036 6-feet 5s. 6d., 076 Patent Elastic Steel, ditto 3-feet .... (fig. 1220) 6-feet .... 9-feet .... Pocket Spring Tapes, in German Silver Cases, with stops and rollers, English yard, and French metre, 3-feet, 6-feet, and 9-feet . 4s., 5s. 6d., 7s. 6d. 10 6 1222 Measuring Tapes made to order with French, Spanish or Portuguese and other Scales in various lengths and mountings. 1223 Levelling or Station Staff, common form . . . 1 10 1224 Sopwith's Station Staff, 14-f eet improved three-jointed, "best socket fittings, each 220 'per pair 440 1225 Ditto ditto, best Painted scale, sliding in three lengths, put together with brass screws, mountings and springs (fig. 1225) each 2 12 6 per pair 550 1226 Ditto Ditto, Metrically divided, same price as above. 1227 Station Staff, 14 feet three-joint half-round Ordnance pattern, per pair . . . . . . . . 7 10 1228 Levelling Staves. Lieut.-Col. Strange's arrangement. The foot is divided into alternate black and white spaces, each representing half a tenth of a foot. All the figures, both those indicating the feet and those indicating tenths of a foot, are on the same side of the scale. The object of this is to obtain more ground surrounding the figures, as on this condition their visibility in a great measure depends. The forms of the figures have been carefully studied. The figures denoting tenths of a foot, are small. It was found that those usually employed are needlessly large. The size now adopted is the result of trial at 10 chains, at which distance they can be easily read with a good 14-inch 'Telescope. Price per pair, 880 45, CORNHILL, B.C., AND 122, KEGENT STREET, W., LONDON. 303 1229 French Pattern Station Staves, 4-Metres long with plain metal B . a. mountings per pair 440 1230 Ditto ditto, 5-Metres, fully divided scale, and inverted figures with best brass mountings . . . . . . . .550 1231 Papers for Level Staves, per foot 003 FIG. 1241. FIG. 1242. ORDNANCE PATTERN MEASURING RODS, SCALES, &c. 1232 24-inch Scale, Boxwood, 25 inches long, If broad, square at the edges, having 1 and 2-inch diagonal scales on two edges, the inch in tenths and eighths, the foot into decimal parts, and a scale of chords to a radius of 12-inches to be used with Beam Compasses 10 6 1233 Architect's Scale, Boxwood, 12i-inches long, l-inch broad, and the inch and half -inch to a foot on one edge, and the quarter and three quarters to the foot on other edge 040 1234 Surveying Scale, Boxwood, 12J-inches long, 1^-inch broad, and chamfered alternately, with diagonal scales, and scales on the edges, also scales of yards and paces to 2, 4, and 6 inches to a mile 040 1235 10-feet Rod, l|-inch square deal painted, divided into feet and quarters on all sides, and figured from both ends alternately, shod with brass . . .100 1236 Link Staff, li-inch square, deal painted black, divided into 10 links on all sides, the centre division marked with a star, shod with brass 12 6 1237 5-feet Surveyor's Measuring Rods, lance wood, tipped with brass, divided on one side into feet and quarters, and on the other into feet, inches, and one-eighths 086 1238 2-feet Rule, Boxwood, 4-fold Gun and Shot Gauge, and the inch divided into 10, 8, and 12 parts 12 1239 Standard Measure, Yellow Dial, 43 inches long, 24-inch wide, I -inch thick, with edge bar along the middle, with four brass plates let in; on the top and edge of one side, 3 standard feet are accurately marked off, and on the other sides two brass plates marked, 5 standard links. In a deal case 1 10 304 NEGRETTI AND ZAMBEA, HOLBORN VIADUCT, E.G., 1240 Levelling Staff, 14-feet, mahogany sliding in 3 lengths, with brass a . d. spring and fittings, Painted Scale, per Pair 550 see No. 1225. 1241 Protractor Semicircular, brass, 6-inch, figured to 180 and to 360^. The arm 6^-inch long, with vernier reading to minutes with clamp screw, and magnifying glass in mahogany case, both sides of the arm parallel to the centre and zero (fig. 1241) . . ,330 1242 Protractor Plain Circular, brass, 8-inch, figured outside to 360, and inside each quarter to 90, divided to half-degrees. In mahogany case (fig. 1242) 220 FIG. 1243. 1243 Beam Compass, Mahogany beam inlaid with holly, graduated to 50 inches, vernier reading to -^ inch, 48 inches between the points, ink and pencil points and clamping screws, in deal case (fig. 1243) 3 12 6 1244 T Square, mahogany, 12 by 25 inches having the stock and blade flush on one side 12 1245 Ditto ditto 12 by 52-inch 16 1246 Angles, 6-inch, pear-tree, Set Square 45 020 1247 Ditto 9-inch ditto ditto 30 030 1248 Straight Edge, Steel, best London make, 2 inches wide, 42-inch, in deal case 140 1249 Ditto ditto ditto 52 -inch, in ditto . . . 1 10 1250 Parallel Rules, 15-inch, best Ebony rolling, plain edges . . . 16 6 1251 Ditto ditto 12-inch ditto ditto 12 6 1252 Ditto ditto 9-inch ditto ditto 10 6 1253 Chain 100 feet with 3 oval rings between each link, stout brass marks, best stout iron 120 1254 Ditto ditto four, Pole Gunter's . . ' 18 6 1255 Arrows, set of 10 by 14-inch, If -inch eye 020 1256 Dark Glass Horizon, in Brass Frame with 3 adjusting screws and Spirit Bubble ground on one side, in Mahogany Box . . .250 1257 Centrolinead, for drawing buildings, &c., in perspective, the instrument giving the line of direction of the vanishing point .330 1258 Elipsographs, for striking Ovals 330550 1259 Ditto ditto, German Silver 4 12 6 1260 Planimeter, Amsler's Patent Brass for computing areas . . . 3 15 6 1261 Integrator, Ansler's 18 1262 Goniometer, Wollaston's Reflecting, for measuring the Angles of Crystals . . .. . 550 1263 Eidograph, capable of reducing any proportion from 1 to 6 inches in box complete . . . . 11 12 12 and 15 1264 Computing Scale. Universal, as used by H.M. Tithe Commission Office, containing 1, 2, 3, 4, 5, 6 chains to the inch, and 6 inches and 5 feet to the Mill in Mahogany box 3 12 1265 Extra Scales fitted to above 056 1266 Computing Form Papers, 10, 20, 30, 40, 50, or 60 per sheet . .050 45, COBNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 305 FIG. 1266. 1266* Pentagraph or Pantograph, in Brass, of the best construction, for ^ reducing or enlarging plans to any proportion : s . a. 18-inches from 660 24-inches 7 10 30-inches, Ordnance size and Pattern with improved Leg and Wheel 9 10 36-inches 10 10 42-inches 11 11 48-inches (fig. 1266) 13 10 1277 Pentagraph, Ebony ........ from 550 1278 Ditto, common White Wood . . . . . 10s 6d. 1 5 FIG. 1280. FIG. 1283 1279 Opisometer or Map Meter, for measuring Curved lines on Plans or Charts, &c 036 1280 Ditto ditto Improved, (fig. 1280) . . . . 4s. 6d. 5 6 1281 Chartometer for measuring and registering distances on Maps. The Chartometer is about the size of a watch, with a small wheel partly projecting from the lower end of the case. To measure any line, the instrument is held upright, and the little rolling wheel is run along the line to be measured ; as the wheel advances an index hand registers on a dial the distance passed over in miles, yards, &c., according to the scale of the map. It can be used for maps of different Scales by a simple substitution of one dial plate for another, a variety of those adapted to the ordnance measurements being contained in the case of the instrument. 1282 Chartometer with Set of Dials, in neat Leather Case . ..110 Ditto ditto German Silver Plated, complete in Case (fig. 1283) 1 12 Ditto ditto Gold plated best finish, complete in Case . .220 Wealemefna, a Pocket Instrument for measuring lines or distances on a map, Nickel Plated, 7s. 6d., [10s. 6d. ; Silver, 10s. 6d., and 12s. 6d. ; Gold ditto, 30s. and 50s. For further particulars of Drawing Instruments, Rules, Scales, &c., see Section Mathematical Drawing Instruments. 1283 1284 1285 306 NEGEETTI AND ZAMBEA, HOLBOEN TIADUCT, E.G., 1236 EEGULATION SET OF INSTRUMENTS, AS SUPPLIED TO NAYAL CADETS. Metal Sextant, in Mahogany Box 8 8s. or 10 10s. Achromatic Telescope, 1 draw 2 10s. Ditto ditto, German Silver Mounted 3 3s. Ebony Parallel Rule, 18-inch, best, 6s. 6d. Mathematical Drawing Instruments, Brass complete, with Rules and Scales, in polished Mahogany Box 2 15s. and 3 10s. Ditto ditto ditto, German Silver 4 10s. 5 5s. Binocular Look-out Glass, in solid Leather Case, with Strap, 4 4s. and 5 5s. 1287 EEGULATION &ET OF INSTRUMENTS, AS SUPPLIED TO THE ROYAL ENGINEERS. Best Pocket Sextant with Telescope, Silver Arc, &c., in Leather Case with Sling Strap, as No. 1303. 5 5 S . Best* Prismatic Compass with Sun Shades and Azimuth Mirror, in Leather Case, with Sling Strap, as Nos. 1167 and 1170 3 3s. and 5 5s. Sketching Protractor 7s. 6d. 50-feet best Tape Measure, as No. 1216 12s. 6d. 18-inch Ebony Parallel Rule 6s. 6d. Binocular Field Glass in solid. Leather Case, with Strap, 4 4s. and 5 5s. Achromatic Reconnoitring Telescope 3 10s. and 4 4s. Mathematical Drawing Instruments, Brass, with Rules and Scales, Mahogany Box, 3 10s. Ditto ditto ditto, German Silver 4 4s. Scales, Rules, Tapes, and Chains made to all Foreign Measures to order. Heliographs for Military Signalling, Universal Sun Dials both for North and South Latitudes, Improved Binocular Telescopes, Aneroid Barometers for Altitude Measurements, &c., &c., see the various sections in this Catalogue. 45, CORNUILL, E.G., AND 122, REGENT STREET, W., LONDON. 307 1288 ESTIMATE FOB A SET OF ORDNANCE PATTERN SURVEYORS 1 AND ENGINEERS' INSTRUMENTS, AS SUPPLIED BY NEGRETTI AND ZAMBRA FOR GOVERNMENT SERVICE. A 5-incli best Theodolite, divided on Silver, with Tripod Stand, as fig. No. 1100, 24 A 15 -inch Dumpy Y Level, with ditto, ditto, as fig. No. 1130 18 18s. Pocket Compass, 3 square, mahogany box. 2 circles of divisions, one, 360, the other figured 4'90. Best bar needle, 16s. Surveying Cross, round, on Ash staff, as fig. No. 1160, 12s. 6d. Drainage Level, with Tripod Stand, fig. 1134 5 5s. A 4-inch Circumferenter, folding sights, ball and socket joint, with jointed tripod stand, as No. 1150 7 7s, Ordnance Pattern Drawing Boards : Antiquarian . 55 by 33 inches. Atlas . . 37 by 28 inches. Double Elephant 43 by 29 Imperial . 32 by 24 Prices various. Prismatic Surveying Compass. 3-inch card, with Silver ring, in Pocket case, as No. 1168 3 10s. Best Pocket Sextant with Telescope, divided on Silver arc with Leather Case and Strap as No. 1303 5 5s. 100 feet best Stout Chain, Brass handles, &c., as No. 1206 1 2s. 4-pole best Gunter's ditto ditto, as No. 1209 18s. 6d. 1 set 10 14-inch Arrows with eye If inch diameter as No. 1210*, 3s. 1 case of Brass Drawing Instruments : 2 10s. and 3 3s. Mahogany box with Tray containing 6-inch ivory scale, 6-inch ebony parallel rule, 6-inch compasses with pen and pencil points, lengthening bar, pen and pencil bow, large and small ivory handle drawing pens, set screw, 6 drawing pins, &c. 3 3s. Best Mercurial Horizon, complete in box 4 10s. 6 -inch Sextant divided on Silver to 10 seconds, with plain tube, two Telescopes with additional power and dark glasses in mahogany case, 10 10s. and 11 11s. Tripod Stand for ditto, with jointed legs 3 3s. and 5 5s. 30-inch brass Pentagraph, as fig. 1266, in mahogany box 10 10s. Mountain Barometer in solid Leather case and brass stand, as No. 1179, 10 10s. Aneroid Barometer or Orometer, as No. 1180 for Altitude measurements, 8 8s. Pocket Thermometer, Oval Boxwood, 7-inches long, to l40 Fahrenheit and Centigrade Scales .... See also Section Thermometers 12s. 6d. Altitude Tables for use with above, sent with each instrument. Boiling Point Apparatus and Tables, see page 92. 308 NEGEETTI AND ZAMBKA, HOLBORN VIADUCT, E.G., NAUTICAL INSTRUMENTS. FIG. 1290. SEXTANTS. s. d. 1589 Reflecting Circle (Troughton's Pattern) 10-inch . . . . 25 1290 Ditto ditto, 12-inch (fig. 1290) . . . . 30 This instrument perfectly corrects the error of the centre by the readings of the three branches of the index ; this property, combined with that of observing both ways, reduces the errors of dividing one-sixth part of their simple value. With this Circle angles may be measured as far as one hundred and fifty degrees. 1291 Ebony Sextant, 8-inch, best, with Ivory arch Achromatic Telescopes, &c., in mahogany case . 6 10 1292 Metal Sextant, 6-inch (Cadets') Circular pattern, divided on Silver reading to ten seconds, three Telescopes, in mahogany case (fig. 1292) - . 880 1293 Metal Sextant, best, 5-inch (Cadets') Triangular pattern, divided on Silver, reading to 10 seconds extra power to Telescope, strapped horizon adjustments in Box . 990 1294 Metal Sextant, 8-inch, Edge Bar Pattern, bronzed limb divided on Silver, reading to ten seconds, in mahogany box 10 10 1295 Metal Sextant, 8-inch, Oval pattern, bronzed limb divided on Silver reading to ten seconds, stump and block adjustment and glass reflector to vernier . 11 11 1296 Metal Sextant, Oval, Triangular, or other patterns, best, bright or bronzed limb, Neutral Tint Shades, and extra power for Telescopes, Glass Reflector, &c., in square polished mahogany case with screwed fittings 12 12 45, COBNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 300 FIG. 1297. FIG. 1292. FIG. 1297*. 1297 Metal Sextant, 8-inch, Best Edge Bar or Triangular Pattern bridge handle divided on Silver reading to ten seconds, bright or bronzed limb, cup and ball tangent screw, swing horizon, and capped adjustments, Neutral Tint Shades, and extra power to Telescopes, and of the most accurate finish, and with all recent improvements, in square mahogany case (figs. 1297 or 1297*) Price 13 13 1298 Lunar Sextant, I-inch, best make, bridge handle, triangle pattern. Extent of arch 150 degrees. Yernier reading to ten seconds, with excess divisions, strapped and capped adjustments, Neutral tint shades ; large size Telescopes, with extra power ; star telescope ; magnifier, &c. In square mahogany box, with lock and key 14 14 1299 Gold or Platinum Arch to either of above 2 12 1300 Tripod Stands for Sextants, with jointed legs, horizontal and vertical action and clamping screw, in deal case . . . . . 550 Quadrants or Octants and Sextants can be supplied of an inferior quality, at slightly lower prices, but they cannot be recommended. 310 NEGRETTI AND ZAMBRA, HOLBOE5T VIADUCT, B.C., FIG. 1301. 1300 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1214 Pillar or Double Platecl {Sextant, 8-incli, reading to ten seconds, with addi- tional power to telescope and Reflectors to verniers, &c., of the very best quality, in Best Square Polished mahogany case (fig. 1301) . 17 17 0> POCKET SEXTANTS 1 FIG. 1303. Pocket or Box Sextant, with Back-work adjustment . Pocket Sextant, best quality, divided on Silver, with Telescope and Tangent adjusting screw, &c. (fig. 1303), with leather case and strap Ditto, ditto, with Cover, divided, hypo and base . Horizon Glasses, for Quadrants . . . pei doz. Index ditto for ditto . ... Coloured Shades, for ditto . . . per set of 7 Horizon Glasses for Sextants . . . per doz. Index Glssses for ditto Neutral Coloured Shades, best parallel, per set of 7 Sets of 3 Achromatic Telescopes for Sextants, best Extra Power for ditto Star Telescopes for Sextants ...... Horn (Index) Magnifiers . . . .per doz. 440 550 5 15 12 140 14 1 10 2 2 160 110 060 15 15 45 COENHILL, B.C., AND 122, KEGENT STREET, W., LONDON. FIG. 1316. FIG. 1315. FIG. 1320. QUADRANTS OR OCTANTS. 1315 Ebony Quadrant, with Tangent screw to index, in oak case (fig. 1315) 1316 Ditto ditto with two Tangent screws, and bar to index and vertical screw (fig. 1316) 1317 Ditto ditto ditto, with six shades . 1318 Telescope with shutter to above, extra .... 1319 Ebony Quadrant, with two Telescopes, reading to 30 seconds, long centre, and seven shades in box . 1320 Metal Quadrant, best quality, divided on Ivory, with Achromatic Telescopes, long centre, seven shades and index magnifier, in mahogany box (fig. 1320) 1321 Metal Quadrant, or Half Sextant, best quality, divided on Silver, with Two Telescopes, long centre, seven shades and index magnifier, in mahogany box . 1322 Ditto, ditto, with extended Arc s. (I 2 10 330 3 10 066 4 10 550 660 6 10 312 NEGRETTI AND ZAMBRA, HOLBOEN VIADUCT, E.G. FIG. 1322. FIG. 1324. ARTIFICIAL HORIZONS. 1322 Black Glass Plane, or Artificial Horizon, with three Levelling Screws, and Ground Spirit Level in box (fig. 1322) 1323 Artificial or Roof Horizon, with Wood Mercury bottle and Trough 1324 Artificial Horizon, Ordnance Pattern, with two Troughs, turned Iron Mercury Bottle, complete in mahogany box (fig. 1324) SUN-DIALS. s. a. 2 10 3 10 4 10 1325 Sun Dials, circular, best Brass, full divided to 5 minutes, with Equation Table, and hand- somely engraved (fig. 1325) : "Diameter 10-in. 12-in. 14-in. 18-in. Price 84s. 115s. 160s. 263s FIG. 1325. 45, CORNHILL, B.C., AND 122, EEGENT STREET, W., LONDON. 313 1326 1327 Vertical Sun Dial of Stout Slate Figures and Divisions en- graved and Gilt. Gilt Iron Rod Gnomon, from 10 10 Ditto ditto, of Slate as above, but with Stout Gun-metal Gnomon (fig. 1327) 14 10 Designs and Drawings of Vertical Sun Dials fur- nished to Architects or Builders, with estimate of Cost. FIG. 1327. Gnomons of any description, for Vertical Sun Dials, supplied to order. N.B. When ordering Sun Dials full particulars should be given of size and form 'of Dial desired, and also the Latitude and Locality where to be fixed up. Skilled workmen sent to take Bearings or fix any description of Sun Dials. PEDESTALS FOR SUN DIALS. 1328 Pedestal of Terra Gotta (fig. 1328) Height 3-ft. 6-in., suited for a Dial 12 to 14 inches diameter 440 Ditto, ditto of Bath Stone . . 7 12 6 Estimates given for Pedestals of any design or material. FIG. 1328. 1329 Globe Sun Dial or A rmillary sphere, 24-inch diameter, Gilt Metal hoops, with hour circle, on the inside of this are painted the hours and divisions, the figures being outlined with gold, nickel-plated rod and terminals. The whole mounted on a solid painted Iron stand .... from 25 314 NEGRETTI AND ZAMBRA, HOLBOftN VIADUCT, E.G., FIG. 1330. FIG. 1332. FIG. 1331. 1330 Sun Dials, with Circular Brass slab and style (fig. 1330) : Diameter . . 6-in. 8-in. 10-in. 12-in. 14-in. Price . . 42s. 52s. 63s. 100s. 120s. 1331 Sun Dials on Slate, the style of Brass, 12 inclies Square (fig. 1331) 330 1332 Sun Dial, with burning lens so arranged that the Sun's rays are thrown on the priming of a small loaded Cannon, and cause it to be fired at noon precisely. The mounting of the lens has a scale corresponding to the sun's decimation for every week in the year (fig. 1332) 3 12 6 4 10 These dials are constructed for the latitude of London. If required for other localities they must be made specially to order, and will be slightly increased in cost. POCKET MARINERS' COMPASSES. FIG. 1334. FIG. 1335. 1333 1334 1335 1336 d. 6 FIG. 1340*. Pocket Compasses, Plain Needle, in square mahogany cases, with stops .... 3s. 6d. 4s. 6d. Ditto ditto, mounted with best Bar Needles and Agate centres (fig. 1334) ... 6s. 6d. 7s. 6d. 10 6 12 6 Ditto ditto, mounted with Floating Card and Agate centres (fig. 1335) . . 6s. 6d. 7s. 6d. Small Pocket Compasses, Round metal cases . 2s. 10 2 12 3 45, COBNHILL, E.G., AND 122, REGENT STEEET, W., LONDON. 315 FIG. 1337*. 1337 Pocket Compasses, in Circular Brass boxes with covers, Magnetic Needles, or Floating Cards, with stops (figs. 1337 and 1337*) 6s. 6d., 7s.6 d., 10 6 12 6 1338 Ditto ditto, with Agate centre, and Bar Needle 12s. 6d. 15 110 FIG. 1340. FIG. 1341. GEOLOGICAL AND SIGHT COMPASSES. See also page 300. FIG. 1342. FIG. 1343. 316 NEGEETTI AND ZAMBEA, HOLBORN VIADUCT, E.G., FIG. 1339. FIG. 1344. FIG. 1363. FIG. 1344. 1339 Brass Gilt Pocket Compasses, in leather cases, Plain s. 1948 Crucible Cases, or Jackets and Covers, of fire-clay, to protect platinum crucibles, and raise them to where the heat is the most intense Crucibles, Wedgwood Ware . Ditto, Skittle shape 3 to 12 inches high, from ....... *Ditto, Bound, with Covers . Ditto, Berlin Porcelain, various from Ditto ditto, not glazed, with perforated covers Calcining Pots, to open in the middle . Cooper's Receiver, for collecting Gases over mercury (fig. 1946) Ditto ditto, Graduated . Cryophorous, Wollaston's, or Frost Carrier or "Rearer (fig. 1948) Cubic Inch Tubes, graduated into lOths and lOOths (fig. 1949) 1950 Ditto ditto on Round Foot (fig. 1950) 1951 Cubic Inch Bottles, (see Specific Gravity Bottles). 1 8 1 1 G 4 1 1 1 8 6 1 2 8 1 7 6 (> FIG. 1949. FIG. 1950. 1949 FIG. 1961. FIG. 1963. FIG. 1952. 1952 Drying Tube, (fig. 1729) a bent tube in which substances to be analysed are placed to dry them, each 1 f> 1953 Drainers for Crystals, Porcelain 2 6 1954 Ditto ditto shallow form 2 1955 Deflagrating Jars, (see Gas Receivers) .... 1956 Dishes, Glass, various shapes . . . from 2 G 1957 Ditto, Evaporating, Berlin ware, various. 1958 Dishes, Evaporating, Wedgwood ware, not liable to stain or crack : Diameter . 2-in. 3-in. 4-in. 5-in. 6-in. 7-in. Price . 4d. 6d. 9d. Is. Is. 4d. Is. 8d. Diameter . . 8-in. 9-in. 10-in. 11-in. 12-in. Price . . .2s. 2s. 6d. 3s. 3s. 9s. 4s. 6d. 1959 Dishes, Sulphuric Acid, for desiccating purposes . 5 1960 Ditto, Washing, flat Porcelain (see Photographic Apparatus). 1961 Dropping Tubes, or Pipettes (fig. 1961) 4d., 6d., and s 1962 Ditto ditto Graduated to grains, &c. . . 3 7 6 1963 Dropping Bottles (as fig. 1963) 2 o 2 G 1964 Dialysers, Graham's Glass, with Welt top and bottom Is. 1 6 2 380 NEGRETTI AND ZAMBBA, HOLBOBN YIADUCT, E.G., 1978 FIG. 1978. 1965 Desiccating Jars, for drying gases by the aid of Chloride of Calcium (fig. 1965) ....... 1967 Desiccating Tubes, with one bulb, and the end straight or bent (fig. 1935) 1968 Evaporating Dishes (see Dishes). 1969 Ettling's Gas Transferors, various forms (figs. 1969, 1969*) 1970 Eudiometer, Volta's, graduated to 200 divisions=2 Cubic Inches (figs. 1970 and 1970*) . ( 1971 Eudiometer, Ure's U-shape (fig. 1971), graduated to 200 divisions=2 Cubic Inches ..... 1972 Flasks, Florence 1973 Flasks, White Flint Glass wide and narrow mouthed, with round and flat bottoms, from 1-oz. to 1-qt., from 1974 Flasks, with Side Neck, for Fractional Distillation, (fig. 1974) .... 1 pint, 2s. 6d. 2 pints, 1975 Flasks, very light, mounted with Brass Stop-Cock for weighing gases ........ 1976 Flasks, Graduated to hold 1 Pint Imperial . 1977 Flasks, Graduated to hold exact quantities Grains, Cubic Inches, or Cubic Centimetres .... s. d. s. d. 7 6 11 6 3 6 7 6 12 6 10 6 4 4 to 4 5 12 6 3 6 2 6 5 6 FIGS. 1974, 1978*. Flasks of Hard German Glass, capable of resisting extreme and sudden changes of temperature ; flat or round bottoms (figs. 1978 and 1978*) : Contents Price 2oz. 4d. 4oz. 5d. 6oz. 6d. 8oz. 8d. 12oz. 10d. 16oz. Is. 3d. 24oz. Is. 6d. 40oz. 2s. 1979 Filter and Funnel Rings of Porcelain (fig. 1979) 4d. and 6d. 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. FIG. 1980. FIG. 1985. FIG. 1984. 381 FIG. 1984. FIG. 1982. FIG. 1983. FIG. 1983*. 1980 Funnels, of Glass (fig. 1980) : Diameter . 1J in. U in. 2 in. 2 in. 3 in. 4 in. 5 in. 6 in. Price 3d. 4d. 5d. 6d. 8d. Is. Is. 6d. 2s. 1981 Funnels, "Wedgwood ware, best quality, from 2-oz. to 2-qts. from 009 FIGS. 1993. and 1993*. FIG. 1994. FIG. 1995. FIG. 1990. 1982 Funnels, long tube, thistle-headed for gas bottles, &c. of blown glass (1982) : Length . 4 in. 13 in. 18 in. 20 in. 24 in. Price . 4d. 6d. 9d. Is. Is. 3d. 1933 Funnels, for filling plain Retorts without soiling the neck (figs. 1983 and 1983*) 026 1984 Funnels, with Handle, for introducing substances into tubes without soiling the sides (fig. 1984) . . .026 036 1985 Ditto with Stopper (fig. 1985) 046 1986 Ditto with Glass Stop-Cock (fig. 1986) . ... 12 6 382 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, B.C., f PU FIG. 2017. FIG. 1979 FIG. 1970. FIG. 1971. FIG. 1970*. FIG. 1998. 1989 Gas B ottle, Clark's, for preparing Sulphuretted Hydrogen, 1990 Gas Bottle, with bent glass tube, for generating Hydrogen, Sulphuretted Hydrogen, Carbonic Acid, or Chlorine Gases (fig. 1990) . . . complete 10 oz. 16 oz. 20 oz. 40 oz. Price . . Is. 6d. 2s. 2s. 6d. 3s. 1991 Gas Flasks with Bent tubes as fig. 1763 1992 Oxygen Gas Retort, of hard glass, with bent tube, for making pure Oxygen from Chlorate of Potash and Oxide of Manganese ....... 1993 Gas Receivers or Deflagrating Jars (figs. 1993 and 1993*) for containing and preserving Gases for experiment : Width. . 3 in. . . 4 in. . s. a. 2 6 026 016 Price Plain. Is. Is. 9d. 2s. 6d. 4s. 6d. Price Stoppered. Is. 6d. 3s. 5s. 7s. 6d. Height. 5 in. . 7 in. . 94 in. . . 5i in. Hi in. . 6i in. 1994 Gas Receivers mounted with brass cap, stop-cock and bladder ferrule, (fig. 1994) about 7 in. high . . . 4 in, wide 9 in. ,, . . .5 in. 1995 Gas Receiver (fig. 1995), mounted with Brass Cap and Stop-cock, and Graduated into Cubic Inches 1996 Globular Receiver, with welted mouth, for showing the combustion of Phosphorous, &c., in Oxygen Gas 1997 Gas Jars, Cylindrical, Stout Glass, for exhibiting the explosive nature of a mixture of Oxygen and Hydrogen 6d. 10 6 12 6 16 6 066 009 010 NEGBETTI AND ZAMBRA, HOLBOBN YIADUCT, E.G. 383 FIG. 2028. FIG. 2098. FIG. 2029. FIG. 2028*. FIG. 2099. FIG. 2099* 1998 Graduated Gas Tubes, for measuring Gases, &c., (figs. 1998 and 1998*) : 4 in. | in. about 1 cubic inch, showing l-100ths cubic inch 6 in. | in. 1 1-lOOtha 7 in. f in. 3 cubic inches l-50fchs 10 in. 1 in. 1 l-10ths 12iin.l|in. 14 l-10ths 1999 2000 2001 2002 2003 Dumas's Gas Tubes, for Nitrogen determinations, 17 in. by 1 in., containing about 20 cubic inches, and divided to either l-10th of a cubic inch or cubic centimetres ......... Liebig's Gas Absorber, for saturating a liquid with Gas, and useful in preparing a solution of any gas Kerr's Gas Tube, stoppered and graduated to 2 cubic inches, so as to show l-10fch of a cubic inch (fig. 2001) Glass Plates, ground, for covering Air Jars : Square . 2in. 2 in. 3 in. 4 in. 8 in. Price . 8d. lOd. Is. Is. 6d. 2s. German Glass Tubing, free from lead, in lengths of about 36 or 18 inches, for convenience of packing : in. bore and under .... per Ib. n. n. down to in. s. d. 046 4 6 5 6 12 6 016 060 026 020 FIG. 2001, FIG. 2012. FIG. 2012*. 384 NEGEETTI AND ZAMBEA, HOLBOBN VIADUCT, B.C., 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 FIG. 2016. , FIG. 2014*. FIG. 2014. FIG. 2015. FIG. 2015* a. d. a. 15 2 1 3 2 10 10 Flint Glass Tubing, very soft, easily bent and worked : i in. bore and under .... per Ib. 1 in. ^in, down to ^in. . . ,, Combustion Tube, German Glass Gauge Tube, for Steam Boilers, &c., according to diameter, see page 197 per inch Glass Rod, of various diameters . . . per Ib. Glass Inhalers Lamp, Hydrogen, Dobereiner's . . . 10s. 6d. Lamps, Spirit, glass, round tops and Brass mounts, (figs. 2010 and 2010*) . . . . . 2s., 3s. Ditto ditto, Common Mountings Lixiviating Jars (figs. 2012 and 2012*) of German Glass strong and convenient in shape, for cold fluids : Contents . 1 pt. H pt. 2 pts. 3 pts. Price . . Is. Is. 4d. 2s. 2s. 9d. Liebig's Retort, with extra neck for passing gases over any substance while heated for distillation, best hard Bohemian glass (fig. 2013) Measures, Graduated Glass, showing ounces and drachms (figs. 2014 and 2014*) : Conical or Cylindrical Form 1-oz. 2-oz. 4-oz. . 8-oz. Price . . Is. Is. 2d. Is. 9d. 2s. Measures, Glass, Graduated Imperial Pint (fig. 2015) 036 Ditto ditto ditto Quart (fig. 2016) 050 Measures divided to show equal parts, Grains, Cubic Inches, or Centimetres &c., to order (fig 2017). Price various. 5 076 10-oz. 2s. 6d. FIG. 2013. FIG. 2030. 45, CORNHILL, E.G., AND 122, EKGENT STRKET, W., LONDON. 385 FIG. 2034*. Each. Each. s. d. at s. u 2018 Measures, Glass, one drachm, divided into drop or 60 minims (fig. 2014*) 012 2019 Ditto, Cubic Inch divided into lOths (fig. 1950) . . 056 2020 Mercurial Trough, Porcelain (fig. 2030) from 026 05-6 2021 Mortars and Pestles, Agate. The prices are only approximate, as they vary according to the soundness of the materials, as well as size : Diameter If-in. If-in. 2-in. 2|-in. 2|-in. 3-in. 4-in. 6-in. Price 8s. 6d. 9s. 10s. 12s. 15s. 20s. 55s. 60s. 2022 Mortars and Pestles, Berlin porcelain . Is. 6d., 2s. 6d., 036 056 2023 Mortars and Pestles, best quality, "Wedgwood ware : Diameter 2|-in. 2i-in. 3-in. 3J-in. 3|-in. 4J-in. 6Hn. Price Is. Is. 4d. Is. 6d. 2s. 2s. 2s. 6d. 5s. 2024 Ditto, in Stout Glass . 2s. 6d. 3s. Od. 3s. 6d. 4 6 066 2025 Mineralogical Anvils, Hard steel, small square . .076 10 (3 2 c 386 NEGRETTI AND ZAMBEA, HOLBORN" VIADUCT, B.C., "* FIG. 2035. 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 Each. s. d. 1 6 1 FIG. 2035*. Muffles . 9d. Is Mixing Jars for Alcalimetry (figs. 2027 and 2027*) . Test Mixers (fig. 2028,2028), for preparing Test Acid; containing 1,000 septems, divided into 100 divisions . Parting Glasses, for assaying (fig. 2029) . . from Pneumatic Trough, mercurial, Berlin ware, for tube experiments (fig. 2030) Porcelain Retort, (Berlin) tubulated and stoppered, contents about forty fluid ounces (fig. 2030) Pipettes, with Round or Pear shaped bulbs (figs. 2032 and 2032*) .... .... 6 Pipettes, or Dropping Tubes, straight bulb, 6-in. long 006 Ditto, with elongated bulb, for use in Edulcoration (figs. 2034 and 2034*) Pipettes, Graduated, for delivering exactly 1,000, 700, 500, 350, or 50 Grains, Cubic Centimetres, Equal Parts, or any quantity to order (figs. 2035 and 2035*), 2s. 6d. 3s. 6d., 5s. 6d. 7 6 Pipettes, with two bulbs, for delivering exactly 500 and 1,000 grains (fig. 2036) FIG. 2037. 2037 Pipettes, for passing a Solution of Potash into a Gas contained in a Tube over mercury (figs. 2037 and 2037) Each. a. d. 026 026 090 009 040 13 6 008 008 010 10 6 050 014 re FIG. 2052. FlG. 2054. FIG. 2052* 2038 RETORTS, Glass, various forms and sizes, see also next page. 45, COIINUILL, E.G., AND 122, REGENT STREET, W., LONDON. 387 FIG. 2053. FIG. 2037*. FIG. 2040. FIG. 2055. FIG. 2041. Each. s. d. 10-oz. Q/ 5 20-oz. 2/6 Each. s. d. 008 01 3-lb. 2s. 010 016 2039 Pipettes, with bent points (figs. 2039 and 2039) 2040 Percolator Glass, for preparing tinctures, &c. (fig. 2040) 1 15 2041 Pourettes or Burettes, divided into Grains, Grammes, Equal Parts or Cubic measures (fig. 2041) . .056 076 8-oz. 2042 Precipitating Glasses, on foot (fig. 2027) 1/6 2043 Ditto ditto Philip's /7 /8 /9 2044 Pulse Tubes ......... 2045 Reduction Tubes, 12-in. tube, 1 or 2 bulbs, straight o bent .......... 2046 Reduction Tubes, with one bulb, the tube bent, for de- composing oxide of copper by heat, in hydrogen gas (fig . 2046) 2047 Retorts, Earthenware, plain . . . . . .016 2048 Retorts, Earthenware, to open in the middle 2s. 6d. 3 2049 Ditto, of hard glazed Stoneware, for Acids . from 2050 Ditto, of Berlin Porcelain, for high temperatures, plain 046 2051 Retort, Porcelain, Stoppered ...... 10 2052 Retorts of hard German glass (figs. 2052 and 2052*) : Contents 2-oz. 4-oz. 6-oz. 8-oz. 12-oz. 1-lb. li-lb. 2-lb. Plain . 4d. 4d. 6d. 8d. 9d. lOd. Is. Is. 6d. Tubulated 7d. 8d. lOd. Is. Is. 2d. Is. 3d. Is. 6d. 2s. 2s. 6d. Stoppered Is. Is. 4d. Is. 6d. 2s. 2s. 3d. 2s. 6d. 3s. 3s. 6d. 2053 Retorts (Small) of blown Glass, 2 to 4-oz. capacity, plain and stoppered (fig. 2053 and 2053*) . . .009 01 2054 Ditto ditto, with bent point (fig. 2054) ... 01 2c2 388 NEGEETTI AND ZAMBKA, HOLBORN VIADUCT, E.G., 2055 2056 2057 2058 2059 2060 2061 2062 FIG. 2059. FIG. 2062. Retort and Receiver, Clark's (fig. 2055), exceedingly useful in small distillation Receivers, of blown glass, 1-oz. to 2-oz. capacity, plain and tubulated (fig. 2056) 6d. Receivers, Plain, bolt heads, short neck (fig. 2057) ; Contents . 4-oz. 8-oz. 12-oz. Price . . 6d. 8d. 9d. Contents . 1-lb. H-lb. 2-lb. 3-lb. Price . . Is. Is. 2d. Is. 6d. 2s. Receivers, with long neck (fig. 2058) : Contents . 1-lb. H-lb. 2-lb. 3-lb. Price . . Is. Is. 2d. Is. 6d. 2s. Ditto, with Tubulure Stoppered, the neck short (fig.2059): Contents . 4-oz. 8-oz. 1-lb. 2-lb. Price . . 8d. lOd. Is. 2d. Is. lOd. Receivers, with Tubulure Stoppered, the neck long (fig. 2060):- Contents . 4-oz. 8-oz. 1-lb. 2-lb. Price . . Is. 2d. Is. 4d. Is. lOd. 2s. 6d. Receivers for preparing Nitric Acid (fig. 2061) Receivers with three necks (fig. 2062) . . . Each. s. (1. Each. d. 016 1A FIG. 2056. FIG. 2027. FIG. 2030*. FIG. 2027* 45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 389 FIGS. 2068. cr FIG. 2070. FIG. 2067. Each.; s. d. 2063 Receivers, V shaped, small size, of German glass (fig. 2063) 2064 Ditto, U shaped, large size, of German glass . . 2065 Receivers, with delivery tube (fig. 2065), for distilling small portions of substances that require the receiver to be surrounded by ice 2066 Ditto ditto fitted to a japanned copper vessel . 2067 Funnel, with bent tube for charging retorts (fig. 2067) 2068 Safety Funnels (Welter's), for gas bottles, retorts, &c., various forms (figs. 2068) ...... 2069 Ditto, with four bulbs, preventing any fluid in the funnel reaching the retort by sudden condensation (fig. 2069) 2070 Safety Funnel, with two valves which obviate the neces- sity of using mercury or fluid in the funnel (fig. 2070) FIG. 2069 Eaclv s. d. 1 3 026 036 10 G 010 016 026 036 056 FIG. 2072. FIG. 2073. FIG. 2073' KEGKETTI AND ZAMER\, HOLBOEN VIADUCT, E.G., 390 2071 Separating Funnel, with Stop- Cock and Glass Cover (fig. 2071) 2072 Separating or Florentine Keceivers (fig. 2072) 2073 Ditto (figs. 2073 and 2073*) with Stop-Cock and Stopper 2074 Specific Gravity Bottles, of 1,000 grains capacity, with adjustable counterpoise, in japanned tin case . 2075 Ditto, of 500 grains 2076 Ditto, of 250 grains 2077 Ditto, 1 cubic inch FIG. 2063. Each. s. d. Eacn. s. d. 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 16 04 18 10 08 07 07 FIG. 2091. FIG. 2234. FIG. 2078*. and FIG. 2065. Spirit Lamps of Glass, with ground caps Brass wick-holders (figs. 2078 and 2078) : Contents . 2-oz. 4-oz. 8-oz. Price . . 2s. 3s. 5s. If with screw wick holders, 6d. extra. Spoons, stout glass, for transferring small quantities of acid, &c., from one vessel to another .... Stirrers, of soft glass, that do not scratch glass vessels in which^they are used : Length . 4-in. 6-iiu 9-in. 12-in. Price (per doz.) . Is. Is. 3d. 2s. 6d. 3s. Stirrers, unprepared, in lengths of 18 or 24-in. per Ib. . Stone Ware Still and Worm, hard glazed, from 1 gall. Stone Ware Adapters and Taps, Acid Jugs, Ladles, Funnels, Bottles, Pots, Evaporating Dishes, and Coolers, &c., of various sizes and shapes Stop -Cocks, solid Glass, accurately fitted, the open end straight and adapted to receive a tube fitted with cork Ditto, with Bent End, for running off a liquid Sulphuric Acid Dish, for desiccating purposes Sulphuretted Hydrogen Gas Bottle (fig. 2087) Suction Tube (fig. 2088), for filling Potash Apparatus and to ascertain if the connections are Air Tight Syphon of a simple form Ditto, with Suction Tube ffi^s. 2090 and 2090*) . 026 026 056 45, COENHILL, B.C., AND 122, EEGENT STREET, W., LONDON. 391 FIG. 2090. FIG. 2112. FIG. 2092. FIG. 2095. 2091 Syphon, Wurtemberg (fig. 2091) . . 2s. 6d 5s. 2092 Syphon, Mitscherlich's, suction tube with bulb, and end bent upwards (fig. 2092) ... 3s. 6d. 2093 Ditto, with Stopcock 10s. 6d. 2094 Syphon, with Negretti and Zambra's adaptation of Syringe, useful where Acids, &c., are being drawn off (fig. 2094) . . . 5s. 6d. FIG. 2094 FIG. 2095* FIG. 2102. FIG. 2087. FIG. 2095*. FlG. 2097. FlG. 2096. 392 NEGBETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., 2095 2096 2097 2098 2099 2100 2101 2102 FIG. 2116*. FIG. 2121. FIG. 2118. 2103 104 FIG. 2122. s. a. Syringes of Glass (figs. 2095 and 2095*) . . . .010 Ditto, with bent point (fig. 2096) Thermometers, various, for chemical purposes (figs. 2097, 2097*) see also pages 153 to 175) insulated in glass tube 3s. 6d. 5 6 Test Glasses, Conical, Clark's pattern (fig. 2098) .008 Test Glasses, Cylindrical, for lecture table (figs. 2099 and 2099*) : Capacity . . 12-oz. 8-oz. Is. 6d. Is. 4d. Ditto ditto Conical form : Contents . . 2-oz. 4-oz. 6-oz. Price 8d. lOd. Is. Test Mixer, Graduated and Stoppered for quantitative analysis (fig. 2101) Test Tubes (fig. 2102), of German Glass, free from lead, carefully the closed end, and bordered at the mouth : Diameter. fin. . . i-in. l-in. . . |-in. . . l-in. l-in. Tube Flasks . Tube Retorts . 1 2 s. A. Length. 2 and 2^-in 3, 3J. 4, 4|, 5, and 6-in. . 4i, 5, S&, and 6-in. . 4, 5, and 6-in 5 and 6-in. .... 7 and 9-in. * per doz. 040 . each 006 076 009 4-oz. d. 8-oz. Is. 4d. 086 rounded at Per Dozen. 010 016 020 2 f 3 ( 4 6 008 45, CORNHILL, E.G., AND 122, REGENT STREET, VV., LONDON. 393 .50- e \/ FIG. 212G. FIG. 2126*. FIG. 2101. FIG. 2109. FIG. 2127. 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 Tubes of Berlin redness : Length . Diameter Price . Porcelain, for containing substances to be heated to 18-in. 24-in. . 4s. 6d. 5s. 6d. 18-in. f-in. 7s. 6d. 24-in. 18-in. f-in. 1-in. 7s. 6d. 10s. 6d. 24- in. 1-in. 12s. 6 Trays, flat, Porcelain, for washing papers, &c. Is. 6d. Ditto, shallow, G-lass ...... from Tubes/three-limb and letter Z, for ad justing apparatus to the exhausting syringe (fig. 2108) . . . .016 Tubes, long Glass conducting U shape (fig. 2109) . Turpentine Bulbs, of glass, for containing volatile 046 036 substances about to be analysed . . . per doz. Watch Glasses per doz. Water Hammers (fig. 2112) Ditto ditto, best make . . . . 5s. 6d. Water Baths, for drying precipitates or explosive compounds, stoneware or porcelain .... Water or Oil Bath, of Berlin Porcelain, especially adapted for drying a precipitate contained on a filter Water Bottle, stoppered, with glass tap, for holding distilled water, &c. ; also useful as Aspirators (figs. 2116 and 2116*) : Contents 4-lb. 6-lb. 8-lb. 12-lb. 20-lb. 24-lb. Price . 11s. 6d. 12s. 6d. 15s. 18s. 25s. 30s. Washing Bottle, Berzelius' Fountain, for washing precipitates by a continual jet of water The Tube only (fig. 2118) Washing Bottles, Gmelin's, fitted to a 16-oz. flask Washing Bottle, Syphon, improved form, in which a current of water is supplied continuously . The Tube only (fig. 2121) Washing Bottle, improved form, complete with sup- port, funnel and receiving jar (as fig. 2122) 010 020 040 040 086 12 036 046 026 1 6 026 6 Q 4 9 16 394 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., Each. a. d. 056 076 2123 Volumeter, 1,000 grains capacity, divided into 100 equal parts (fig. 2101) 2124 Woulffe's Bottles, well made plain necks, so as to cork easily ; with two necks shape as fig. 2124 : Contents i-lb. 1-lb. 2-lb. 4-lb. 6-lb. 8-lb. 10-lb. Price . Is. Is. 6d. 2s. 6d. 3s. 8d. 5s. 7s. 8s. 6d. 2125 Woulffe's Bottles, with three plain necks, shape as fig. 2125 : Contents -lb. 1-lb. 2-lb. 4-lb. 6-lb. 8-lb. 10-lb. Price . 2s. 2s. 6d. 3s. 4d. 4s. 8d. 6s. 9s. 6d. 11s. 6d. 2126 Woulffe's Bottles, with one neck, accurately Stoppered, as figs. 2126 and 2126 : l-pint. 2-pints. 3-pints. 2-neck 3s. 2d. 3s. 8d. 4s. 6d. 3-neck 3s. 8d. 4s. 6d. 5s. 6d. 2127 WoulfFe's Bottles, a set of three l-pint, in a Mahogany tray, fitted with safety funnels, tubes and connectors (fig. 2127) 18 6 FIG, 2137. FIG. 2137*. FIG. 2145. FIG. 2138. APPARATUS FOB ORGANIC ANALYSIS, &c. s. d. s. d. 2128 Apparatus for illustrating the Composition of Water Synthetically, by burning Hydrogen gas in atmospheric air ........ 050 2129 Berzelius' Sulphuretted Hydrogen Apparatus (figs. 2129, 2129*) 086 2130 Ditto, ditto, with extra Washing Bottle, ... 1 12 6 2131 Cavendish's Apparatus for detonating a mixture of Oxygen and Hydrogen Gas, illustrating the Composition of Water 2 12 6 2132 Donavon's Apparatus for Filtering Caustic Potash (fig. 2132) 1 10 2133 Dobereiner's Extracting Apparatus (fig. 2040) . 1 15 2134 Fritzch's Apparatus, for Analysis of Carbonates (fig. 2234) 020 2135 Glass Apparatus for showing Diminished Bulk by mixing Sulphuric Acid and Water (fig. 2135) . 050 2136 Glass Apparatus, for Exhibiting the Philosophical Candle and producing musical sounds by Hydrogen Gas " from 10 6 2137 Leibig's Potash Apparatus, made very light from German glass, free from lead (figs. 2137 and 2137*) .026 036 45, CORNIIILL, E.G., AND 122, EEGENT STREET, W., LONDON". 395 FIG. 2139. FIG. 2140. 2138 Mitscherlich's Potash Apparatus, very light, (fig. 2138) 2139 Marsh's Apparatus for detecting Arsenic (fig. 2139) . 2140 Ditto, ditto, on Stand (fig. 2140) 214 L Clark's Apparatus for. detecting Arsenic (fig. 2141) . 2142 Percy's Apparatus, for Analysis of Carbonates . 2143 Ure's Apparatus for determining the quantity of Nitrogen ..04 2144 2145 2146 2147 2148 2149 2150 FIG. 2132 FIG. 2136. FIG, 2129* 036 3 7 9 10 7 056 Will and Varrentrap's Nitrogen Bulbs .... Nitrogen Bulb with Horsford's Modification (fig. 2145) Bell-Shaped Dialyser of Glass, with two Flanges Cylindrical Glass Jars, for using above Dialysers, Tube Form, Dr. Alfred S. Taylor's Form, for testing Mineral Poisons Parchment Paper, for use with Dialyser, best quality 84 by 6 inch, Is. 6d. ; lOf by 6 inch, 2s. ; 12 by 12 inch, 2s. 6d. ; 14 by 12 inch, 3s. 6d. per dozen. Flat Conical Glass Basins, with Spout for holding Distilled Water below the Dialyser, and collect the Diffusate 3s. 6d. 5 6 06 066 Sets of Chemical Apparatus and Tests adapted for the Analysis of Soils, Manures, &c., &c., or for the examination of Adulterated Articles of Focd fitted up to ordir. See also end of Chemical Section, page 411. 39C NEGEETTI AND ZAMBRA, HOLBOEN YIADUCT, EC., FIG. 2153. Sets of, seepage 400. CHEMICAL AND PHILOSOPHICAL INSTRUMENTS AND APPARATUS. 2151 Balances, Chemical, with Glass Cases, highly finished and carefully adjusted, to turn with T ^th of a grain or one Milligramme 8 8s. 10 10 12 12 2152 Balances, Assay, with framed beam and steel knife, edges resting on Agate planes, sliding weight on beam, with adjustments, in Glass Lantern, with levelling screws, &c., of the most delicate accuracy, to turn with TTJ Voth of a grain 15 15 25 2153 Balances, Assay or Chemical, of the highest precision, fitted with all recent improvements, adjustments and appliances. Plate Glass for bottom of the case (fig. 2153) 35 to 50 Decimal Weight 2154 Balance (fig. 2154) for Assay- ing, Analysis, or Diamond weighing, will carry 500 grains and turn with -ji^th of a grain ; all bearings of Steel. In plain Glass Case, with -key arrange- ment for lifting . .660 Ditto ditto with Set Screws and Spirit Level . .770 2155 Balance for determining the Specific Gravity of Fluids, whether heavier or lighter than water, to the third place of decimals. This Balance consists of weigh-beam, a plunger FIG. 2154. to be immersed in the fluid ; fitted with Thermometer, Set of Weights and Riders, Glass Solution Jar, &c., in wood case price 4 10 45, CORNHILL, E.C., AND 122, REGENT STREET, W., LONDON. 307 FIG 2170. FIGS. 2168, 2171, 2167*, 2165, 2167 2166 2169, 2167* 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167* 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 Balances and Scales with Weights, for Commercial, rough Laboratory, or counter use, see pages 405, 408. Balloons, for inflation with Hydrogen or Coal Gas : Diameter . 9-in. 10-in. 12-in. 16-in. 18-in. 20-in. 36-in. Price . Is. 6d. 2s. 6d. 3s. 6d. 4s. 6d. 5s. 6d. 8s. 6d. 36s. Each. s. d. Balloons, oval shape, 3-ft. high and 2-ft. diameter Balloons, fish shape, 15-in. and 30-in. long . Bladders, mounted with Ferrules Ditto ditto and Stop-Cock 076 Bar Compound, for showing the unequal expansion of metals by heat ...!*.'. Bars of Antimony, Bismuth, Copper, Iron, Lead, Tin, and Zinc, for precipitating metals from solution, from Blowpipes, common Brass 010 Ditto, Black's (fig. 2165) 010 Ditto, Bergman's improved (fig. 2166) with two jets . Blowpipes, various patterns : Berzelius' (fig. 2167) ; Pepy's (fig. 2167*) with movable Jet, for use at any angle ; or Wollaston's Pocket form 2167* . . from 16 Blowpipe, Hemming's Safety, Oxy-Hydrogen (fig. 2168) Blowpipe, Oxy-Hydrogen, complete with Lime-Holder, Stopcocks, &c., (fig. 2169) Blowpipes, Spirit, Self-acting, for bending glass tubes, strong Tin (fig.2170) * Ditto ditto, Copper Ball (fig. 2171) .... Blowpipe, Self-acting, Gas and Steam, very convenient and powerful for small solderings, brazings, or fusions .......... Blowpipes, Spirit, or Russian Furnace .... Ditto ditto, with ring and support .... Blowpipe, Tilley's Water Pressure, with jets, &c., complete, in japanned tin ...... Bruner's Aspirator, Japanned Tin or Zinc (see fig. 78* page 72). See also Water Bottles Glass Blower's Table, with best double-action bellows, jointed motion to jet-holder, and two jets (fig. 2177) . Glass Blower's Lamps (figs. 2178 and 2178) Spirit Lamps, of glass (fig 2179) .... Each. s. d. 110 18 6 036 10 6 050 12 6 004 016 020 076 12 6 12 6 2 10 10 6 15 220 15 110 1 12 6 150 330 050 036 398 KEGRETTI AND ZAMBEA, HOLBORN VIADUCT, E.G., FIG. 2177, 2179* Glass Blower's Apparatus, Patent, consisting of a circular column of japanned zinc, table covered with zinc (having brass-bound edges) double -action cir- cular bellows, drawer, and universal -jointed iet (fig. 2179) . . . 2179f Ditto ditto without Zinc cover to the table FIG. 2179. 5 10 500 FIG 2178. FIG. 2179. FIG. 2178" 2180 Hot Blast Blowpipe, for temperatures above those obtained by the ordinary gas and air blowpipe. It will be seen by the wood-cut (fig. 2180) that the tube of the Air Jet is coiled round the gas tube, both being heated by a Bunsen Burner underneath, each being controlled by separate taps. The jet when reduced down to a small point of flame is nearly equal in power to the Oxy-Hydrogen Jet, readily fusing a moderately thick Platinum "Wire. It is a most useful arrangement for Chemical Soldering, and general Workshop use. Price 16s. 6d. 2181 Hand Blower (fig. 2181) for use with above 16 2182 Foot Blowers, for Blowpipe work, Autogenous Soldering or Furnace use. 21s., 30s., 35s. 45, CORNHILL, E.G., AND 122, EEGENT STEEET, W., LONDON. 399 FIG. 2180. FIG. 2181. Each. s. d. 2183 Blowpipe Jets, Platinum .... from 2184 Blowpipe Forceps of Brass with fine points . 2185 Ditto ditto Steel and Platinum Points . 5s. 6d. 7 6 2186 Ditto Spoons, Platinum or Silver . . . from 2187 Blowpipe Apparatus, for Pocket, containing requisites for Assaying metals, in case ..... 2188 Bellows, portable Double, for table furnaces . from 2189 Blowpipe, Mineral Fragments, per box .... 2190 Brass Tobacco Pipe, for blowing Gas Bubbles 2191 Brushes, Test Tube ..... from 2192 Ditto, Phial and Bottle ...... 8d. 10 2193 Caoutchouc in sheets ....... 2194 Caoutchouc Gas Bags, wedge shape, see also Lantern Section ........ from 2195 Ditto Connectors, for joining tube apparatus from 2196 Ditto, Vulcanised Tube . . . .per foot, from 006 2197 Ditto Varnish ....... per oz. 2198 Ditto Water Bottles ....... 10 6 2199 Capsules of Platinum, Silver, Copper, &c., various. 2200 Chauffers with cover and pipe for increasing heat . 10 6 2201 Chemical Labels ..... per set 8 2202 Combustion Furnace of stout Sheet Iron 2203 Cross of Four Metals for showing unequal power of conducting heat ........ 2204 Connecting Pieces, Brass Angle and T Pieces, Union Joints for uniting Stop-Cocks, &c. . Is. Is. 6d. 2 6 2205 Connecting Ferrules, Brass, for Bladders . . .010 2206 Crucibles, Platinum, Silver, Iron, &c., various. 2207 Crucible Jacket, iron plate, to hold any size Platinum Crucible ......... 2208 Crucible Stands and Supports, various . . . .002 2209 Ditto Tongs, straight, bent, &c., of various sizes Is. 6d. 2 6 2210 Each. s. d 026 026 10 6 050 1 10 6 1 10 12 030 006 016 016 1 10 002 020 004 110 12 6 030 076 060 046 016 020 008 046 Fletcher's Blowpipes and Furnace Apparatus supplied to order. 400 NEGRETTI AND ZAMBBA, HOLBORN VIADUCT, B.C., FIG. 2212. Each. s. a. Each. a. d 10 6 2211 Condensers, Liebig's form for Distillation (fig. 2212) The steam passes through a long Glass tube, inclosed in an outer Metal tube ; in the intervening space water is made to flow continuously, and rapid condensation is effected. 2212 Support for Liebig's Condenser, best make, in wood, capable of being elevated and inclined to any angle (see fig. 2212) 10 6 2213 Ditto ditto, Metal ......... 16 2214 Adjustable Wooden Stand for water vessel (see fig. 2212) 2215 Cork Borers, a set of four, without case ... 026 2216 Ditto, of polished brass, set of six, in a case . . 046 2217 Ditto, a set of twelve 076 0126 2218 Deflagrating Spoon, the bowl rivetted to the stem, with a sliding cover for the jar (fig. 2218) .... 008 2219 Ditto, Ground Cover, to fit the top of Glass Receiver . 026 2220 Drying Apparatus, or Hot Air Bath, on stand, japanned tin, from 110 2221 Ditto ditto Copper, or Copper tinned . .220 440 2222 Decimal Weights, from 1,000 grains to a 10th of a grain, in mahogany box 1 10 2223 Ditto, from 1,000 grains to 1 -100th of a grain, the smaller weights of Aluminium or Platinum . 220 2224 Diamonds, for Writing and Engraving on Glass from 10 6 2225 Ditto for Cutting ditto 15 6 to 2 2 2226 Dishes, Evaporating, Copper .... from 026 2227 Ditto ditto Copper tinned inside . 030 2228 Ditto ditto Copper plated with silver . 066 2229 Ditto ditto Silver. . . . from 12 6 2230 Ditto ' ditto Enamelled Iron ... 026 2231 Evaporating Capsules, of Platinum : Diameter Contents l-in. |-in. 1-in. l-16th oz. l-10th oz. i-oz. i-oz. 2-in. |-oz. 21-in. i-oz 2f-in. ll-oz. Price variable, according to weight, about 35s. per oz. 45, CORNHILL, E.G., AND 122, BEGENT STREET, W., LONDON. 401 FIG. 2257f. FIG. 2257*. 2232 Files, for cutting Glass Tube, with wood handle . 2233 Files and Rasps, for fitting Corks to tubes, with wood handle 2234 Flexible Tube, Metal, for conducting gases, from per foot 2235 Ditto ditto Vulcanised India Rubber 2236 Filter Paper, very thick and coarse .... 2237 Filter Papers, Circular, ready cut for use; give a very minute portion of ash, and filter rapidly ; in packets of 100 : Diameter . 2] -in. 2|-in. 2|-in. 4^-in Price per 100 . 3d. 5d. 7d. 8d. 2238 Filtering Paper, superior quality, per quire . 2239 Ditto, Swedish, per quire, Munktell's Genuine 2240 Filter Paper Boxes, japanned, holding 200 filters: For No. 1 23456 Filters. 7d. 8d. 9d. Is. Is. 3d. Is. 6d. 2241 Funnels, Gutta Percha from 2241* Ditto, Ebonite v eacl1 2422 Ditto, Tin and Tinned Copper .... 2243 Furnaces, Aikin's blast . . . . . 2244 Furnaces, Black's Universal, of Sheet Iron, with Cast Iron fittings, applicable to the reduction and assay of metallic ores, cupellation of silver, &c., full size . 2245 Furnaces, portable Table Earthen and Black lead, from 2246 Ditto, Black Lead, larger, for retorts or tubes, &c. 2247 Furnaces, round Iron, lined with fire lute or brick, applicable for general chemical purposes . 2243* Furnace Blowers, see page 398. 2244* Forge, improved single blast. These Forges possess great power, and are very portable . . Round 2245* Forge, Patent double Deck or Rivet, having large powers of blast, insuring great and rapid heat (fig. 2245) Round 006 Is. Is. 4d. 016 550 016 10 010 019 2 046 020 036 026 18 6 5 10 1 10 440 330 550 660 880 2 D NEGRETTI AXD ZAMBRA, HOLBORN VIADUCT, E.G. FIG. 2247*. 2246* 2247* 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2257* 2257f FIG. 2245*. Each. s. d. Each. Forge, improved Portable Iron, adapted for soldering and brazing purposes, jewellers' uses, and suited for amateur mechanics Square 550 660 Forge, portable Iron, improved with double bellows, the whole fitted together with nuts and screws for convenience of packing, arranged with connecting screw and pipe for blast furnaces (fig. 2247*) . 10 10 A most useful article for persons residing in foreign parts, or Emigrants. Gas Apparatus, complete, for making oxygen and hydrogen in quantities for the Oxy-Hydrogen Light (see page 363) 330 Gas Retort, Copper, with Conducting Tube, for the preparation of Oxygen Gas, without Bag . . .110 1 10 Ditto, Wrought Iron 110 Ditto, Iron, small 12 6 Gas Burners, or Furnace (Bunsen's), adapted for burn- ing common gas, mixed with air, without smoke ; for boiling, distiUing, &c. (figs. 2252, 2252*, 2252f) 5s. 6d.; 8s. 6d. 12 6 16 Gas Blowpipes, see ante, page 398. Gas Lamp, conveniently arranged on bronzed adjusting table stand as a reading lamp, a microscopic illumi- nating or preparing lamp, and also useful for chemical operations, see page 271 (fig. 364*) Microscope Section price 300 Gauge Brass, for showing the expansion of metals' by heat, see also Section Phenomena of Heat . 060 Gutta Percha Basins, Funnels, Troughs, Trays, Tube, &c., &c., . . various sizes and prices to order. Gutta Percha Bottles, round, for Acids, &c. . 2-oz. 4-oz. 8-oz. 16-oz. Price . . Is. Is. 4d. Is. 6d. 2s. 6d. Hydrometers for testing Heavy and Light fluids of all kinds, see pages 176 to 195. Graduated Test or Mixing Jars for use with above, 3s. 6d. and 6s. 45, OORNHILL, E.G., AND 122, EEGENT STEEET, W., LONDON. 403 FIG. 2252. FlG. 2252-f. Each. s. d. 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2278* 2279 2280 2281 Hammers, Mineralogical . . . from Iron Spheres, strong; this apparatus shows the expansive force in the congelation of water Ladles, small Iron from Lamps, Chemical Argand, for oil, with cottons and mandril, complete (fig. 2261) . . . t 7s. 6d. Ditto ditto with double concentric wick Lamp, Argand Fountain, for Oil, with adjusting screws to fix on retort stand . . . . Lamps, Davy's Safety, for Miners Ditto ditto recently improved (fig. 2265) . Ditto, Bunsen's for Blowpipe, with tray Lamps, Spirit, small brass (fig. 2267) .... Lamps, Spirit, Brass, with two sliding rings, a conve- nient stand, for small evaporating dishes, &c. ' . Lamps, Argand, Spirit, Brass with Circular Wick Lamps, Hydrogen, Dobereiner's, for producing instantaneous light with a jet of hydrogen Magnets, Steel, Horse- shoe shape . 6d., 9d., Is. Magnetic Oxide of Iron, or Natural Loadstone, Specimen pieces or slabs .... from Magnesium Wire per yard Masks, of Wire Gauze, for protecting the face Magnifying Glasses, Pocket, for examining minerals, crystals, &c. (See " Optical Section," page 224) ls.6d. Metallic Vessel, Leslie's Cube, with polished and blackened surfaces, for showing the absorption and radiation of heat .... ... Mercurial Troughs, Iron and Mahogany . from Mohr's Burettes, with support (fig. 2277) Ditto ditto without stand Mortars and Pestles, of Cast Iron . . . from Mortars of Steel, for crushing hard minerals Melting Tongs, for Furnace Work .... Nippers or Cutting Pliers, for cutting wire . 086 15 Each. l s. d. 060 046 008 10 6 110 18 12 150 070 066 16 1 10 1 10 050 046 006 12 6 036 046 5 6 6 16 7 6 4 1 12 4 6 6 6 2 6 3 6 2 D2 404 NEGEETTI AND ZAMBKA, HOLBORN VIADUCT, K.C., 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 FIG. 2267. FIG. 2333. FIG. 2335.1 FIG. 2265. FIG. 2287. Each. d. Each. s. d. Platinum Crucibles, Basins, and Evaporating Dishes, various sizes . . . ' . . about per oz. Platinum Retorts, half-pint .... about Ditto ditto one pint . . , Platinum Forceps and Spoons Is. 6d. 3s. 5s. 6d. 8 No exact prices can be given for Platinum Vessels, as the value varies considerably. Pepy's Gas Holder, of japanned Tin or Zinc, with long pressure funnel, stopcocks and connectors complete, to hold about 2,000 cubic inches Ditto best mounted, Copper japanned (fig. 2287) with Graduated Gauge Tube . . - . , Pneumatic Troughs, Japanned Tin, for collecting gases, small size, Round for Tube Experiments . Pneumatic Troughs, Oblong Shape, 1st size . Ditto ditto 2nd size . . . ... Ditto ditto 3rd size . . . (fig. 2291) Pneumatic Troughs, of any size or shape, made to order, in Copper, Tin, or Zinc, &c. Reflectors, highly polished metallic, for experiments on radiant heat from, per pair Ditto, Plated Copper from Ditto, Stands, for Reflectors and Iron Ball . . .060 See also section Phenomena of Heat. Retorts, Lead, for Fluoric Acid, 16 oz. . , Retort Stands, small Iron foot . . . from 1 15 11 16 0120 330 550 076 10 12 6 18 6 1 10 2 10 080 10 6 026 45, CORNH1LL, E.G., AND 122, REGENT STREET, W., LONDON. 405 FIG. 221)1. FIG. 2298. FIG. 2298*. 2298 2299 2300 2301 2302 2301* 2302* 2303 2304 2305 2306 2307 2308 2309 2310 with and 3 rings 2s. 6d., 5s. heavy foot (fig./) Each. 8. 07 01 Retort Stands, Iron foot and rod, 2 (fig. 2298 and 2298*) . Ditto ditto Brass, large, page 375 . . . ' Ditto ditto, large with Fountain, Argand Oil Lamp, and three rings . Sand Baths, small round Copper, for Retort Stands Ditto ditto, in Copper and Iron, of various forms and sizes, for Furnaces. Stands or Supports for ditto Tripod .... Scales and Weights, in Pocket case, for Diamonds or Gold dust . Scales, for weighing Gold and Silver, &c., with Troy Weights (fig. 2302) 1 10s. Scales and Weights, large, to stand on Counter or Table, for the rougher uses of the Laboratory 1 Is. Ditto ditto of greater precision, with Decimal Weights, &c Scales, Bullion, t o weigh 300, 500, 1,000 to 2,000 ozs. 30, 40, Grain Scales, Brass Pans, and a set of weights from 120 grains to f-grain, in Oak box .... Ditto, superior make, in Mahogany box (fig. 2306) Ditto, with Glass Pans, in Oak box .... Ditto, with Glass Pans and box-end beams, in Mahogany box .......... Grain Scales, with Pillar, on Mahogany stand (fig. 2302) Balances, Chemical, with a set of Decimal Weights to the tenth of a grain, to carry 1000 grs. in each pan ; and turn with the tenth of a grain when thus loaded ; in Mahogany box (fig. 2310) See also page 396. FIG. 2277. Each, d. a. d. 6 14 16 18 6 2 2 2 2 3 3 2 10 1 15 6 6 026 076 220 3 10 3 10 440 60, and 70. 6 036 056 066 6 18 1 10 330 440 406 NEGKETTI AND ZAMBRA, HOLBOEN VIADUCT, E.G. 2311 2312 2313 2314 2315 2316 2317 2318 2319 FIG. 2310. FIG. 2302. FIG. 2319. 2320 Stills, Strong Tin, portable, 2 gallons 2321 Ditto, Copper, 1 gallon and 2 gallons Shears, Cutting, small Sieves, of hair, lawn, and wire, for straining or sifting . Spatulas, Steel, with handles .... from Ditto Platinum Ditto Silver 10 Still, Working Model, of Copper, handsomely japanned, suitable for the Lecture Table (fig. 2316) . Stills, small, of strong tin, with Argand Lamp and Worm Tube, 1 quart 11 Ditto ditto 2 quarts 15 6 Stills, portable, Strong Tin, with worm and tub, for preparing pure water for Chemical or Photographic purposes, for use on an ordinary fire, 1 gallon (figs. 2319, 2319*) 160 1 10 1 15 220 FIG. 2319*. 220 220 2 10 45, CORNHILL, B.C., AND 122, BEGENT STREET, W., LONDON. 407 FIG. 2316. 2322 Stills, Copper, best make, Portable Iron Frame and s. d. s. a. furnace, with pewter worm and tub, 2 gals. . 550 2323 Ditto ditto 5 gals . 880 2324 Ditto ditto 10 gals 13 13 2325 Distilling Apparatus for Ascertaining the Original Gravity of Beer after fermentation, or Alcoholic Wine Test, see page 193. 2326 Stopcocks, common Brass 026 2327 Ditto, Best make, Brass 036 2328 Ditto, Iron, small 060 2329 Syphon, Pewter and Copper .... from 076 2330 Ditto ditto with Stopcock . 10 6 2331 Syringes, Exhausting or Condensing (see [also Pneumatic Apparatus) 10 6 12 6 2332 Supports, various, for Tubes, Retorts, Receivers, &c. 3s. 6d. 5 14 2333 Taper Holder of wire, for experiments in Oxygen Gas, &c. (fig. 2333, the wire only) .... 006 2334 Taylor's Hot Air Bath, stout Sheet Iron, with double body and bottom, and long chimney .... 16 2335 Ditto ditto, Copper (fig. 2335) 1 15 2336 Test Papers, red or blue litmus, and Turmeric, per book 002 2337 Ditto Neutral (reddened by acids and turned blue by alkalies), very delicate .... per book 002 2338 Test Tube Brushes, tipped with sponge . . .006 010 2339 Test Tube Holders 008 2340 Test Tube Stands, for eight test tubes, with draining pegs (fig. 2340) 018 2341 Ditto ditto for twelve test tubes, with draining pegs 036 2342 Test Tube Stands, of Mahogany polished, with double set of holes, for twenty -four and thirty- six test tubes 050 066 2343 Thermometer, Standard (fig. 2343) see also page 32 . 220 2344 Ditto Chemical, with plain exposed bulb, graduated to 300 (fig. 2344) , 056 2345 Ditto ditto with Brass Hinged Joint to scale (fig. 2345) 10 6 12 6 408 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, B.C., FIG. 2343. FIG. 2347. FlG. 2346*. FIG. 2344. ll /^> 1 p 1!! Ij in i i m n 1 j FIG. 2362*. FIG. 2346. FIG. 2340. FIG. 2345. s. d. s d. 2346 Thermometers, Isolated for dipping in Acids, &c. (figs. 2346 and 2346*) (see also pages 153 to 174) . .076 10 6 2347 Thermometers, with bent tube, for Hot Air Bath, Drying Chambers, &c. (fig. 2347) . 10 6 2348 Tubing, Vulcanised India Rubber, per foot, 4d., 6d., 8d., 010 2349 Vice, to fasten to Table 10 6 2350 Wire Gauze, for experiments on Flame, of various sizes, from 1 2351 Weights, Grains and Drachms . . per set, each 006 2352 Ditto Platinum, grains . . . per set 036 2353 Ditto Aluminium, 1 grain to l-10th ... 036 2354 Ditto Brass, 1,000 grains to l-100th ... 200 2355 ditto ditto 50 Grammes to 1 Milligramme . 1 18 2356 Weights, Sets of Troy, 10 ozs. to -^th of an ounce . 3 10 2357 Sets of ditto ditto, 20, 30, 40, 50, and 100 oz. 5 10 2 5 45, CORNHILL, E.C., AND 122, REGENT STREET, W., LONDON. 409 s. d.. s. d. 2358 Standard Grain Weights, in mahogany box, containing 10,000, 6,000, 3,000, 2,000, 1,000, 600, 500, 300, 200, 100, 60, 30, 20, 10, 5, 3, 2, 1, -6, -3, '2, 1, -06, -03, '02, '01 . 440 2359 Standard Grain Weights, smaller sets . . . . 3 13 220 2360 Gramme Weights, 1 Kilogramme to 1 Milligramme, in Mahogany Box 440 2361 Ditto ditto, 100 Grammes to 1 Milligramme, in mahogany Box 2 10 6 2362 1 Gramme and its subdivisions in 1,000 parts in Platinum, for assaying Gold or Silver, in Box . . 1 15 English or Foreign Weights and Measures of all kinds supplied to order. For Decimal Weights, see page 398. 2362* Standard Barometers (fig. 2243), for Laboratory use, see pages 8 to 11. CHEMICAL CABINETS AND PORTABLE LABORATORIES. FIG. 2366. 2364 Youth's Chemical Cabinet, containing sixty chemical preparations, and useful apparatus, without deleterious and dangerous articles ; and adapted for ex- citing a taste for chemistry in the young. No. 1, in paper case 056 2365 Youth's Chemical Cabinet, No. 2, in cedar case, with hook fastening 076 2366 Ditto ditto No. 3, in stout mahogany case, French polished, and with lock and key (fig. 2366) 10 6 2367 First Steps in Chemistry and Companion to the Youth's Chemical Cabinet ; containing a series of select, amusing, and instructive chemical experiments 006 2368 Student's Chemical Cabinets, containing a larger assortment of apparatus, in mahogany cabinets, with lock and key . 11 111 6 2 2 2369 Student's Chemical Cabinet, No. 5, contains the necessary re-agents and instruments for the various operations of qualitative analysis, testing in the humid way, and includes blowpipe apparatus, fiuxes, and tests for the discrimination of ores, minerals, &c. The apparatus, &c., is conveniently arranged in a mahogany cabinet, with drawer, tray, lock and key 880 410 FEGEETTI AND ZAMBEA, HOLBOEN VIADUCT, E.C., FIG. 2370. 2370 Student's Chemical Cabinet (fig. 2370), a good useful working chest ; it con- tains upwards of 79 chemical preparations and re-agents, and a large assortment of apparatus, &c., in a mahogany cabinet, with lock and key 330 2371 Agricultural Test Chests, fitted with re-agents and apparatus for the qualitative analysis of soils, manures, &c. The tests are pure, and the apparatus of a useful size, carefully arranged in a cabinet, with lock, key, &c. 3 3 5 5 8 8 2372 Toxicologieal Test Chests, contains all the re-agents and apparatus necessary for the accurate analysis of any substance suspected of containing Poison, in accordance with the present advanced state of this branch of chemical science 550 These Chemical Cabinets and Portable Laboratories are specially arranged for the use of persons who have not convenient space for keeping such apparatus, or where portability combined with security is important. In all other cases, where ample and secure space can be devoted to the purpose, Messrs. Negretti and Zambra would recommend one of the following Sets of Apparatus, or purchasers to make their own selection from our Chemical Section. 2373 SETS OF CHEMICAL APPARATUS FOR ELEMENTARY EXPERIMENTS. Adapted for illustrating the Theory and Practice of Chemistry, the Production and Examination of Gases, &c., &c. ; suitable for Students studying Elementary Chemistry, and for verifying the main facts on which the Science is based. 2374 Three 'Guinea Set of Apparatus. Retort Stand, with three sliding rings ; Two two-ounce retorts ; Two half -pint retorts ; Globular receiver ; Black's blowpipe ; Nest of Hessian crucibles ; Apparatus for making oxygen gas over a spirit lamp ; Glass Spirit Lamp ; Gas bottle with acid funnel and delivery tube, for making Hydrogen gas, &c. ; Balloon for Hydrogen gas; an assortment of six flasks, for solutions, digestions, &c. ; Gas bottle, with bent delivery tube, for making Chlorine 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 'ill and other gases ; Pipette or dropping tube, &c. ; Book test papers ; Set of six cork borers, with file for sharpening them, and steel rod, in japanned case ; Glass funnel, and supply of filtering paper ; Funnel support, with movable arm ; Balance, with a set of weights, from oz. to | grain, in box ; Tall test glass, for precipitations ; Two Clark's test glasses, for testing, &c. ; Six Test tubes, of hard German glass ; Test tube stand ; Two stirring rods ; Glass tubing, for fitting up gas bottles, for conducting tubes, &c.; Pneumatic trough, with movable shelf and tray; Two gas jars; One gas jar, with glass stopper; One transfer jar, mounted with brass cap, stopcock, bladder and bladder piece, and brass jet; Two porcelain evaporating basins ; Graduated glass measure ; Deflagrating ladle, with cover ; Three watch glasses, for evaporations, &c.; File for cutting glass tubing; Glass plates, Porcelain mortar. Including a strong Packing Case. 2375 . Five Guinea Set of Apparatus. Retort Stand, with iron foot and rod, and three sliding rings ; Two plain retorts ; Two tubulated retorts, one receiver ; Set of four porcelain capsules, for evaporations, crystallizations, &c. ; Pneumatic trough, with movable shelf [and tray ; Bell or transfer jar, mounted with brass cap and stopcock ; Bladder, mounted with ferrule ; One brass jet, for experiments on Oxygen ; Pestle and Mortar ; Glass tubing : Half-a-dozen glass stirrers : Two glass funnels, filtering paper ; Three flasks, for solutions, digestions, &c. ; Bars of zinc, copper, and iron, for use in testing, &c. ; Two books of neutral test papers ; One dozen hard German glass test tubes ; Test tube stand for one dozen tubes ; Tall test glass, for precipitations ; Three Clark's test glasses, for testing, &c. ; Black's blowpipe ; Blowpipe lamp ; Clark's gas bottle, for making sulphuretted hydrogen* &c. ; Gas bottle, with bent glass delivery tube, for preparing Chlorine and other gases ; Platinum foil and wire ; Glass spirit lamp ; Graduated glass measure, 4 oz. ; Pipette ; Improved apparatus for making Oxygen over a spirit lamp : Cylinder, for supporting flasks, basins, &c. ; Sand bath, iron ; Six watch glasses ; Set of cork borers, in case ; Two files, one for cutting glass tubing, and the other for enlarging holes in corks, Balance and set of weights ; Nest of Hessian crucibles. Including a strong Packing Case. 2376 Blowpipe Cabinet. A complete Set of apparatus, &c., for the Mineralogist in Polished Box. Blowpipe with Platinum Jet, Forceps with Platinum Points, Platinum wire Foil and Capsule, Geological Hammer Steel, Steel Forceps and Spatula, Steel Crushing Mortar. Chisel, triangle File, Cutting Pliers, Pocket Magnifier, three Porcelain Capsules, Porcelain Slab, Glass Stirrers and Pipette, Hard Glass Tubes, Arsenic Tubes, Charcoal for Blowpipe. Blowpipe Lamp and Stand, Charcoal Supports and Tin foil. Re-agents : Carbonate of Soda, Borax, Murocosmic Salt, Bone Ash, Gypsum, Nitre -Silicia, Fluor Spar, Lead, Iron "Wire Graphite, Starch, Rock Salt, Oxalate Nickel, Oxalate Potass, Boracic Acid, Potassium Broulphate, Potassium, Cobalt Nitrate, Hydrochloric Acid. Nitrate of Silver, Magnetic Needle, Test Papers assorted, &c 550 Larger and more complete Sets fitted up to order. Ten to twenty Guineas. PURE CHEMICALS, TESTS, OR RE-AGENTS SUPPLIED IN ANY QUANTITY AT THE LOWEST MARKET PRICES. 412 NEGEETTI AND ZAMBEA, HOLBOEN VIADUCT, E.G., 2377 2378 2379 2380 ELECTRICAL, GALVANIC, MAGNETIC, ELECTRO-MAGNETIC, AND THERMO-ELECTRIC APPARATUS. FIG. 2377. FIG. 2393. FRICTIONAL ELECTRICITY. Cylinder Electrical Machines (Nairne's Model), on Mahogany Stands, with Japanned Conductors . Ditto with Brass Conductor ..... Ditto second size, 6-in. by 4-in. Ditto third size, 7 -in. by 5 -in Ditto fourth size, 8-in. by 6-in. (fig. 2377) Ditto fifth size, 10-in. by 8-in FIG. 2378. Each. a. d. 110 Each. s. d 5 10 10 2 3 5 Cylinder" Electrical Machine, with double rubbers and collecting forks, brass conductors, French polished mahogany stand (fig. 2378) 660 10 10 Cylinder Electrical Machines, with a selection of the most instructive and interesting experiments with frictional electricity, Packed in a neat case . 4 4s. 5 5 10 10 Plate Electrical Machines (Ramsden's arrangement, 1760) with Brass Conductor, mounted on polished Mahogany Frames, and finished in a superior manner. Ditto 9-inch Ditto 9-inch Ditto 12-inch Ditto 12 inch, Plate Electrical Machine with Double Receiving Forks, best make ..... Ditto 15 -inch with ditto Ditto 18-inch (fig. 2380) with ditto .... Ditto 24-inch ditto 1 12 3 3 4 10 5 10 6 10 8 8 11 11 45, CORN HILL, E.G., AND 122, REGENT STREET, W., LONDON. 413 f FIG. 2381. FIG. 2380, 2381 2382 2383 2384 2385 2386 2387 2388 2389 Plate Electrical Machine. Winter's arrangement. The Plate in this machine is mounted upon an insulating Glass axis ; this, in connection with a large wood-covered metal circle placed on top of the prime conductor, considerably increases the length of spark ; from a 15-inch plate t> to 8-inch sparks may be readily obtained (fig. 2381) Woodward's Double 24-inch Plate Electrical Machine, a very splendid and powerful instrument . Holtz' Electrical Machine, with 22-inch Vulcanite Plate Holtz Machine, mounted with 2 movable Plates . 5 10 26 20 25 Plate Electrical Machines, with a selection of Apparatus for exhibiting the most popular and interesting experiments in Frictional Electricity, Packed in a deal case, with lock and key . . 6 6s. 10 10 20 Volta's Electrophorus, for obtaining the electric spark, a very useful instrument for the Laboratory, Resin Base with Brass Plate . . . from Electrophorus, cheap arrangement, 12-inch disc of Gutta Percha, and 10-inch disc of Tin Plate with a Glass Handle ........ Electrophorus, Improved, with Vulcanite or Ebonite Base, with Brass Plate (fig. 2388) . 5-inch, 1 8s. Cannon Electrophorus, mounted with an electrical cannon, for firing mixtures of hydrogen and atmospheric air (fig. 2389) 12 6 086 9-inch, 220 2 12 6 414 NEGKETTI AND ZAMBEA, HOLBORN VIADUCT, B.C., FIG. 2390. FIG. 2391. 2390 Voss Electrical Machine is an improved form of Holtz' Machine, mounted on a polished Mahogany frame and base. This machine can be used in almost any atmospheric condition, and under favourable circumstances the length of spark obtainable from it is more than two-thirds that of the diameter of the larger Glass Plate, with an exceedingly small amount of manual labour. The excitement of the Yoss Machine is produced by holding against the G-lass Plate a flat piece of Yulcanite which has been previously electrically excited by rubbing it upon woollen cloth or cat's fur (fig. 2390) . price 4 10 2391 Piche's Electro-Static Induction Machine, is a modified arrangement of Holtz's machine. It is composed of a circular plate of Vulcanite, in front of which are placed two collecting forks in metallic connection with two brass rods mounted on jointed insulated supports; these rods are so contrived that they can be moved in any direction, or the terminal balls brought close together. On one side and at a small distance belr'nd the revolving plate is placed a flat oblong plate also of Vulcanite, termed the Induction Plate, To put this machine in action the Induction Plate is withdrawn from its groove on the base of the stand, and excited by rubbing it briskly with a cat skin or a woollen cloth (Flannel), and quickly replaced in the groove, then upon rotating the circular Yulcanite plate by the handle and multiplying wheels, it will be found that one fork or comb will collect Positive, and the other Negative Electricity. Price of Piche's Machine as fig. 2391, with 18-inch Yulcanite Plate 12 12 2391* Wimshurst's High Tension Electric Machines. An improved form of Nos. 2390 and 2391. These machines can be used in place of Induction Coils for illuminating Yacuum Tubes, Spectroscopic Experiments, &c. They are made of three sizes, including a packing case 16-inch plate, 6; 12-inch, 5; 8-inch, 2 2s. 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 415 FIG. 2394. FIG. 2392. 3392 40 . d. Armstrong's Hydro -electric Machine (fig. 2392) This apparatus consists of a very strong boiler, constructed to sustain great pressure, for evolving Electricity by the friction of water and steam against other substances. It is fitted with safety valve, water gauge, condensing tubes, jets, collecting and discharging rods, &c. The boiler is heated by a coke or charcoal fire, and supported on insulating glass legs with rolling castors. 2393 Leyden Jars (fig. 2393)- Contents . J-pint. i-pint. 1-pint. 2-pints. 4-pints. Price . 2s. 6d. 3s. 6d. 6s. 8s. 6d. 15s. 2394 Electrical Batteries, consisting of 4, 6, 9, 12, or more Leyden jars, mounted in frames or cases, with brass conducting rods and balls (fig. 2394) 2 10s. ; 3 3s. 6 6 10 10 2395 Medical Leyden Jars, mounted with Lane's Discharging Electrometer, to regulate the intensity of the shock given to a patient (fig. 2395) 12 6 18 3396 Leyden Jars, mounted, to show that the charge is not in the coatings, as those with which it is charged can be removed, and others put in their place, the glass retaining the electricity (fig. 2396) . . 16 6 FIG. 2388. FIG. 2427. FIG. 2396. FIG. 2389. 416 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., ft \ A FIG. 2397. FIGS. 2400, 2400*. FIG. 2398. x\ FIG. 2401. Each. FIG. 4201*. Each. 2397 Jointed Dischargers, with glass handles, for discharging electrical jars, batteries, &c. (fig. 2397) . 8s. 6d. 11 2398 Ditto ditto French pattern, with two glass handles (fig. 2398) 15 2399 Small Discharging Rods, not jointed . . . .03 2400 Medical Electrical Directors, with glass handles, for pa.ssing a shock through any part of the body (figs. 2400 and 2400*) 3s. 6d. 5 6 076 2401 Electrical Directors, for the Eye and Ear (figs. 2401 and 2401*) 10 6 12 6 2402 Two Jars, mounted, for explaining the Franklinian theory (fig. 2402) 14 2403 Ditto ditto, with Insulated Stand, ball and wire (fig. 2403) 140 2404 Biot's Apparatus, for illustrating the distribution of electricity on the surface of insulated conducting bodies, It consists of a sphere of copper, supported on an insulating glass rod and stand, and two thin copper hemispheres of such a size as to enclose the sphere. The covers are fitted with glass handles, so that they can be removed from or placed over the sphere, without the hands touching the metal ^fig. 2404) . . 2 15 FIG. 2395. FIG. 2405. FIG. 2404 45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 417 FIG. 2409. FIG. 2408. 2405 Metal Roller, with. Glass Handle and a roll of Tin Foil, mounted upon an Insulating Stand, to show the effect of an expansion of surface in reducing the intensity of electrictity whilst the absolute quantity remains the same (tig. 2405) 1 12 6 2406 Electrometer, Coulomb's Torsion. This instrument measures very minute quantities of electricity, and with careful manipulation will give accurate values of the attractive and repulsive force of free electricity communicated to any body of known area . . . , . . . .330 2407 Henly's Universal Discharger, with press and table, for deflagrating the metals by electricity, or exposing various substances to electrical action. 1 12 6 2408 Ditto, with Carbon Forceps, &c., adapted for Frictional or Voltaic electricity (fig. 2408) 220 FIG. 2412. FIG. 2425. FIG. 2413. FIG. 2414. FIG. 2411, 2409 Cuthbertson's Self-acting Balance or Steelyard Discharger (fig. 2409), for indicating the force or strength of the discharge from an electric battery by the position of the shifting weight on the graduated balance arm 2 15 6 2 E 418 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.C., FIG. 2411* FIG. 2418. FIG. 2417. FIG. 2420. 2410 Balance Electrometer, or Electroscope, very simple and delicate. It consists of a light metal rod suspended on a point, insulated on a glass stand. The rod is mounted with pith balls on each end, which will be attracted or repelled according to the quality of the electricity affecting it 11 2411 Bennet's Gold Leaf Electroscope (Ginger's improved form) : used for showing very minute quantities of electricity (fig. 2411). See also page 115 . . .110 1 10 2411* Cavallo's Pith Ball Electroscope 110 2412 Volta's Condensing Electroscope (fig. 2412), see page 425. 1 10 2413 Henly's Quadrant Electrometer, with graduated arc, for experiments with accumulated electricity (fig. 2413) . 2414 Cavallo's Pith Ball Electroscope, with stopcock for exhaustion (fig. 2414) 2415 De Luc's Electric Column or Pile, composed of discs of silver, zinc, and paper, mounted glass tubes with brass caps at the ends 2416 Zamboni's Electric Pile. The elements in this pile are silver, black oxide of manganese, and paper, insu- lated with sulphur : it is more energetic than De Luc's ; mounted in glass tubes, terminated with brass caps . 2417 Bohenburger's single leaf Electroscope, for ascer- taining the presence and quality of very feeble electrical currents (fig. 2417). See page 116 2418 Peltier's Electrometer (or Dr. J . Milner's, 1733) for mea- suring the tension of electricity by the deflection of a needle ; an extremely sensitive instrument (fig. 2418) 2419 Harris's Balance Beam Electrometer, for estimating in grain weights the attractive power exerted between two oppositely electrified surfaces .... 440 076 1 10 6 220 1 14 330 1 10 330 440 550 45, COENHILL, B.C., AND 122, REGENT STREET, W., LONDON. 419 c FIG. 2431. FIG. 2424. FIG. 2444. FIG. 2432. FIG. 2434. FIG. 2437. 2420 Harris's Unit Jar Electrometer, with graduated slider, for charging Leyden jars, or batteries, with known quantities of electricity (fig. 2420) .... 2421 Saussure's Electroscope, for experiments on atmospheric electricity (fig. 2411*) ....... 2422 Harris's Electro-Thermometer, for measuring the heating power of electricity 2423 Kinnersley's Electrical Thermometer, a modification of Harris's instrument for exhibiting the transient expansion of air by the passage of Electricity through it (fig. 2423, page 426) 2424 Calorometer, Hare's, or jointed insulated forceps, for conveniently supporting wires, through which it is wished to pass an electric current, to ascertain the heating power by the length of wire heated (fig. 2424) 2425 Electrical Condenser, consisting of two brass plates, one supported on a glass insulating stem, the other rest- ing upon a conducting stem jointed at the bottom (fig. 2425) 2426 Improved Electrical Condenser and Apparatus, for experiments upon disguised or paralysed electricity, arranged to connect with a gold leaf electroscope (fig. 2426) 2427 Magic Picture, or Fulminating Pane, in frame, for giving slight shocks (fig. 2427) 2428 Insulated Stools, for medical and other purposes, where it is required to insulate a body from the ground 2329 Ditto, with Mahogany top (fig. 2429) see page 415 2430 Insulated Adjusting Table Stand, with hollow Glass support, best make (fig. 2430) see page 426 Each, s. d. 7 10 1 1 s. d. 1 15 150 1 16 100 1 10 18 220 10 6 16 1 10 10 6 2s 2 420 NEGRETTI AND ZAMBBA, HOLBOEN VIADUCT, B.C., FIG. 2438. FIG. 2440. FIG. 2441. FIG. 2445. Each. s. d Each. s. c 086 16 15 066 14 2431 Names or Words, arranged upon glass, with pieces of tin foil, which may be rendered luminous in the dark by the agency of electricity (fig. 2431) . 7s. 6d. 10 6 150 2432 Star, formed of spangles of tin foil, on a flat glass (fig. 2432) from 056 2433 Bird, formed of spangles of tin foil, on a flat glass from 056 2434 Painted Glass Plane, on Stand, in different colours, with devices of tin foil, for showing the electric light (fig. 2434) 2435 Lightning Plate De Londe's is constructed of a plate of glass mounted upon a firm base; one side of the glass is entirely coated with tin foil to within a short distance of its edge, and the opposite side is covered with small spangles of tin foil placed at a short distance from each other. This form s a modified Ley den jar : when charging the plate, the electricity darts about its surface in all directions, and when discharged a brilliant display of electric light is produced 110 220 2436 Iron Chain, for illuminating a darkened room by electricity per yard 006 2437 Diamond Spotted Jars, showing a beautiful light when discharged in a dark room (fig. 2437) . . 8s. 6d. 15 1 10 2438 Egg Stand, for exhibiting eggs, &c., rendered luminous during the passage of electricity (fig. 2438) 2439 Faraday's Improved Egg-Stand, with Glass Cylinder . 2440 Image Plates, brass stand with hook, to connect to prime conductor, for pith figures, illustrating electrical attraction and repulsion (fig. 2440) .... 2441 Image Plates, with insulated glass support for the upper plate, connection being made from the prime conduc- tor, the figures are removed from the attractive influence of the cylinder (tig. 2441) .... 12 6 15 18 6 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 421 FIG. 2446. n FlG. 2447. FIG. 2450. FIG. 2451. u FlG. 2452. FlG. 2454 Each. s. d. ' Each. 8. d. 030 2442 Dancing Figures, made of elder pith, plain Is., jointed 020 2443 Pith Ball Stand, another illustration of electrical attraction and repulsion ...... 050 2444 Ditto, with ball and wire (fig. 2444) .... 080 2444* Pith Balls ....... per doz. 010 016 2445 Grotesque Carved Head, with Hair, for illustrating the principle that bodies similarly electrified repel each other (fig. 2445) ........ 2446 Electrical Figure, carved of cork, representing a swan, which, placed on the surface of a vessel of electrified water, will be attracted to any part by presenting the finger to it (fig. 2446) ...... 2447 Ditto ditto, representing Neptune, sea-horses, &c., (fig. 2447) ....... from 2448 Electrical Spider, by electrifying which, and presenting a ball, will be attracted, but repelled by a point 2449 Coloured Glass and Paper Plumes, to exhibit the repulsive action of similarly electrified bodies . 2450 Electrical Flask, with brass cap and valve for exhaus- tion, to imitate the aurora borealis (fig. 2450) . . 2451 Glass Globe, with stop-cock, sliding wire, with forceps, &c., for showing the passage of electric light through a partial vacuum or different gases (fig. 2451) . 2452 Luminous Conductor, or apparatus to exhibit the effect of a falling star, with valve for exhaustion (fig. 2452) 110 2452* Ditto with Stop Cock, large size . . . .220 330 2453 Bucket and Syphon to suspend from the prime conductor ; this experiment shows that water, which previous to being electrified only fell in drops, when electrified runs in a stream, and in a dark room is luminous 3s. 6d., 5s. 6d 040 066 046 076 010 026 056 076 12 6 220 2 12 6 422 NEGBETTI AND ZAMBEA, HOLBOKN TIADUCT, B.C., FIG. 2455. FIG. 2457. FIG. 2461. 2454 2455 2456 2457 Hand Spiral, consisting of two glass tubes with brass caps, the inside one covered in a spiral form with spangles of tin foil, showing when presented to an excited conductor, a spiral stream of electrical light (fig. 2454) 3s., 4s., 5s. 6d Set of Five Spirals, Best, with coloured tubes (fig. 2455), on mahogany pedestal, with insulated revolving balls in the centre, which, by their motion, produce a splendid succession of spiral lines of light 220 Luminous Chain Experiment, (fig. 2456) 15 Revolving Spiral, on stand. The electric fly or whirl revolves by the dis- persion of electricity from the points, presenting a very beautiful appearance in a dark room (fig. 2457) 16 6 FIG. 2468. FIG. 2464. FIG. 2465. 45, COKNHILL, E.G., AND 122, EEGENT STREET, W., LONDON. 423 FIG. 2466. FIG. 2467. FIG. 2469. Each. 2458 Gamut of Bells. This experiment consists of eight bells arranged on a stand, with an electrical fly or whirl carrying a clapper, which, in revolving, strikes each of the bells (fig. 2458) 2459 Set of two Electrical Bells. The simplest form of the experiment, one bell communicating with the prime conductor, the other with the ground, and made to ring by the alternate blows of a brass ball suspended between them by a silk cord (fig. 2459) 2460 Set of Three Bells, on brass rod, to suspend from the conductor. The action of these is the same as the preceding (fig. 2460) 2461 French Arrangement for illustrating the chiming of bells by electrical action, one bell being connected with the inner, and the other with the outer coating of a Leyden jar (fig. 2461) 2462 Electric Fly or Wheel, for producing motion by the dispersion of electricity from points (figs. 2462 & 2462*) 2463 Three ditto on one stand 2464 Franklin's Electrical Self-moving Wheel, with glass spokes, terminating with brass- balls. Placing the wheel between a charged battery and a conductor to the earth, the wheel is caused to rotate by attraction and repulsion (fig. 2464) .... 2 2465 Electrical Orrery or Planitarium, representing the motions of the sun, earth, and moon (fig. 2465) . d. 036 2 Each. s. d. 220 036 086 110 FIGS. 247 r FIG. 2473. FIG. 2472. FIG. 2471. 424 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, B.C., FIG. 2477. FIG. 2481, Each. s. d. 2466 Electrical Mill, showing rotation produced by electricity given off from the points of the vane (fig, 2466) . 2467 Electrical See -Saw, illustrating electrical attraction and repulsion (fig. 2467) 2468 Electrical Inclined Plane, the fly revolving by the dispersion of electricity from the points, and ascend- ing the incline (fig, 2469) 2469 Apparatus for explaining the theory of Thunder Clouds (figs. 2469), 2470 Harris's Thunder Cloud Apparatus, constructed of a light metal needle, balanced to turn very freely upon a vertical point con- nected with one coating of a large Leyden jar, or Electric Battery. One end of the needle is covered with light cotton wool, to represent a cloud, which can be arranged to approach either figs. 2471, or 2471*, and the discharge takes place ; a very interesting experiment ........... 2471 Thunder House (Dr. Priestley's), or Obelisk for showing the use of lightning conductors in protecting buildings (figs. 2471 and 2471*) 12 6 2472 Fire House, for illustrating the same fact (fig. 2472) . 2473 Powder House, for showing the necessity of a continuous metallic lightning conductor, which in this experiment is broken in the centre of a cup containing gunpowder. This is ignited and explodes by an electrical discharge, blowing down the house (fig. 2473) .... 2474 Sturgeon's Apparatus for igniting Gunpowder, Alcohol, JEther, &c., by electricity (fig. 2474) .... 2475 Apparatus for the ignition of Phosphorus, consisting of two brass cups, insulated upon glass supports, for holding small pieces of phosphorus ; between these is a stand for a small lamp or candle ; the passage of electricity between the cups will carry the flame towards the phosphorus, and ignite it (fig. 2475) . Each. s. d. 110 15 110 150 100 15 1 4 1 10 200 12 6 14 NEQKETTI AND ZAMBRA, HOLBOBN VIADUCT, E.G. 425 o 9 t FIG. 2474. FIG. 2475. FIG. 2476. 2476 2477 2478 2479 2480 2481 1 15 Electrical Sportsman. This popular experiment consists of a Leyden jar, and a figure carved to represent a Sportsman shooting; two wires are inserted in the jar, at the end of one some pith birds, the other is brought near the point of the gun. A chain from the prime conductor is connected with the wire communicating with the base of the jar, and as soon as the machine is put in action the birds rise, but fall as if shot immediately the jar is discharged (fig. 2476)1 6 Electrical Cannons, for firing a mixture of Hydrogen gas and Atmospheric Air by an electric spark (Kg. 2477) Electrical Pistol, for the same experiment (fig. 2478) . Apparatus and Material for charging ditto with Gas . Electrical Powder Cannon, for firing Gunpowder by charge of a Leyden Jar, similar to one figured in '' Galvanic Section " . from 16 7 4 1 1 10 11 10 6 Electric Bomb, or Mortar, of hard wood or ivory, having two wires so arranged that when a large Leyden jar or Electric Battery is discharged through them, a sudden expansion of the air in the Mortar is caused, and will expel with considerable force a small ball, of cork placed nearly air-tight in the barrel of the bomb. If a drop of JEther be placed in the chamber the result is more violent (fig. 2481) 12s. 6d. 15 2482 Eudiometrical Tube, for exploding detonating mixtures of gas by the passage of an electric current or spark passed between two platinum wires. See also " Eudiometer," page 380 10 6 2483 Volta's Condensing Electroscope (fig. 2412), invented by Yolta, is a modification of Singer's and Bennett's Gold Leaf Electroscopes. The metal wire to which the gold leaves are affixed, terminates in a flat metal plate, as seen in the wood-cut, and the instrument is supplied with a second metal plate of similar size, fitted with an insulating glass handle, the one being termed the collecting, and the other the condensing plate ; both the plates are coated with insulating shellac varnish. Particulars of the method of using Volta s Electroscopes will be found in Ganot's Physics. Price 1 10 Volta's Electroscope is sometimes mounted with Light Straws or small Pith Balls instead of Gold leaves. 426 FEGBETTI AND ZAMBBA, HOLBOBN VIADUCT, E.G., FIG. 2423. FIG. 2426. FIG. 2430. Ench. s. d. 2485 Insulating Table Stand (fig. 2430), for supporting and insulating Electrical apparatus, 14-inches adjustment 076 Ditto ditto Best make with heavy base . . , . . 10 6 2486 Faraday's Butterfly Net, with Glass handle and Insulating Stand (fig. 2486) 086 2487 Wire Gauze Cylinder (fig. 2487), on Insulating Stand, with hollow ball for exhibiting that electricity is distributed only upon the surface of conductors similar to Biot's Experiment. No. 2404, page 416 price 12 6 2488 Electrical Conductors, a set of three forms, consisting of a Sphere, Cone, and Cylinder of wood, covered with Tin Foil, and mounted upon Insulating stands (figs. 2488, 2488, 2489.) 2489 Elipsoidal Conductor, is for showing the unequal distribution of Electricity (fig. 2489) price 1 10 2490 The three Conductors can be supplied with one Insulating Stand . 18 6 Most of the Electrical Apparatus catalogued in this section will be found fully described in Noad's Lectures on Electricity, Noad's Student's Text Book, Ganot's Physics, translated by Atkinson, and Tyndall's Lessons in Electricity. FIG. 2488. FIG. 2489. FIG. 2488*. FIG. 2-486. FIG. 2487. 45, CORNHILL, E.G., AND 122, EEGENT STREET, W., LONDON. 427 2488 2489 J I 2492 2493 2494 Cylinders, of Shellac, Sealing Wax, Sulphur or Yulcanifce for illustrating Resinous excitation . . . . 2 6 6 6 Apparatus for producing Lichenburg's Figures, consisting of a flat Resin cake, a bottle of Powdered Red Lead mixed with Powdered Sulphur, a square of Muslin Gauze ; in a box . Cylindrical Glass Tubes, for exhibiting vitreous Electrical excitation . Fur Rubber, or prepared Cat's Skin, for Electrical excitation Fox Brush for ditto ditto . Cylinders, Electrical . . 3s. 6d., 4s. 6d., 066 Circular Glass Plates, for Electrical Machines, cut and polished : 12 6 016 030 10 18 2 12 Diameter Price 9-in. 6s. 12-in. 12s. 15-in. 21s. 18-in. 30s. 24-in. 66s. 2495 Circular Ebonite Plates : for Electrical Machines. Diameter 12-in. 15-in. 18-in. 24-in. 30-in. 36-in. Price . 16s, 22s. 30s. 46s. 66s. 86s. 2496 Conductors for Electrical Machines, black japanned Tin or Zinc 3s. 6d. 2497 Ditto, Brass .... from 2498 Glass Jars, for coating, ;-pts. Is., pts. Is. 6d., qts. 2s., 3 pts 2499 Glass Handles . . .Is. 6d., 2500 Gutta Percha Handles .... 2501 Glass Legs or Supports . Is. 6d., 2502 Glass Rod, for Electrical apparatus, per Ib. 2503 Brass Balls . . . 9d., Is., Is. 6d. 2504 Ditto, with Collar and Wire, for Mount- ing up Leyden Jars . . . 2s. 2505 Amalgam, per box 2506 Brass Chain, per yard .... 2507 Flexible Conducting Wire, per yard, very convenient 006 2508 Strips of Gilt and Silvered Leather, to illuminate by the electric spark, per yard 020 2509 BaUs of Ivory, Bone,Boxwood, and Ebony 010 020 2510 Brass Clamps, for fixing apparatus to table 030 046 2511 Strong Iron Clamps for Ditto . . 036 2512 Patent Copper Wire Rope, solid Copper Rod, or Flat Copper Band, Lightning Conductors, with the point and all staples, FIG. 2512. &c., complete for fixing (fig. 2512). For full description and prices, see pages 127 and 129. 5 6 6 6 7 6 3 2 3 6 1 6 2 6 2 2 6 ). 2 6 2 2 6 2 6 3 6 1 6 ESTIMATES GIVEN FOR FIXING OR REPAIRING LIGHTNING CONDUCTORS. 428 NEGBETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., VOLTAIC ELECTRICITY. FIG. 2520. FIG. 2513. FIG. 2527. YOLTAIC OE GALVANIC APPAEATUS. 2513 2514 2515 2516 2517 2518 2519 2520 Volta's Pile of 50 pair of Zinc and Copper Plates, soldered together, on a mahogany stand (fig. 2513) . Zinc and Copper Plates, circular, soldered together per doz. Pairs of Silver and Zinc Wires, soldered together, for Voltas Couronne de tasse .... per doz. Pair of Circular Zinc and Copper Plates, with Glass handles, for showing the production of electricity by contact. . . . ...... Zinc and Copper Sieves, with Glass Handle, to illustrate the Electric Action produced by sifting metal filings on a delicate Electrometer .... per pair Cruikshank's Batteries, Zinc and Copper, in mahogany troughs, for Medical purposes, 25 pairs of plates, Ditto 60 pairs of plates, 2-inch (fig. 2519) Wollaston's or Babington's Battery of ten pairs of 4-inch plates, Zinc and Copper, with divided trough (fig. 2520) ......... Each. s. d. Each. s. d. 16 180 050 080 12 6 14 220 2521 Cruikshank's, Wollaston's, or Sturgeon's Batteries, are charged with dilute Sulphuric acid in the proportion one part, by measure, strong acid, to fourteen parts Water ; or, if very strong action be required for a short time the quantity of the acid may be increased, say 1 to 10. Dr. Fyf e found the use of a solution of Sulphate of Copper in these batteries increased their action. 45, CORNHILL, E.G., AND 122, REGENT STREET,^., ^LONDON. 429 FIG. 2522. JFIG. 2531. 2522 2523 2524 2525 2526 2527 Each. s. d Each. a. d. 076 10 6 10 10 Sturgeon's Cylindrical Battery, of Copper and Zinc, in Stoneware pot (fig. 2511) a simple and cheap but very useful battery, for elementary class instruction ; for feeble but continued action solutions of either common Salt or Hydrochlorate of Ammonia are to be used ; and dilute Sulphuric Acid, one part strong acid to ten parts water, for stronger action .... Calorimotor, Wollaston's, 1 pair of 6-inch zinc and double copper plates, in a trough .... Calorimotor, Hare's, of extra large size Daniell's Sustaining Battery, consisting of a cylinder of Zinc and Copper, separated from each other by a porous earthenware tube, and excited by a solution of Salt and Water, or diluted Sulphuric acid, one part acid to ten parts Water, in contact with the zinc, and a Saturated solution of Sulphate of Copper in the other cell. Price for single cells . . 5s. 6d. 8 11 Daniell's Battery, containing six f-lb. cells of the above, in mahogany tray ....... Ditto ditto containing twelve 1-lb. cells, in mahogany tray (fig. 2527) 1 12 6 440 Daniell's Battery is the best arrangement for use where a steady and very uniform current is desired for any length of time ; much used for Electro-plating, Gilding, and Electrotyping purposes. 2528 Mullins Battery, a modification of Daniell's Cell, consists of cylinders of Zinc and Copper, separated from each other by Bladder or Porous Earthenware ; excited by a solution of common Salt and Water in contact with the Zinc and a solution of Sulphate of Copper in the other cell. Single cells . . 5s. 7 15 Larger sizes of Daniel's or Mullin's Batteries in single cells or series, to order. 430 NEGRETTI AND ZAMBRA, HOLBORff VIADUCT, E.G., FlG. 2529. Fl(J. 2534. FIG. 2530. 2529 Smee's Batteries, in round Stoneware Pots, so arranged with brass clamps that the zincs can be easily removed for cleaning and amalgamating, and replaced (fig. 2529) -pt. 5s. 6d. 1-pt. 8s. 6d. 2-pts. 11s. 6d. 3-pts. 14s. Smee's Batteries are constructed with one ;plate of thin Platinized Silver, and two plates of Amalgamated Zinc. For charging Smee's Batteries one part by measure of strong Sulphuric Acid, to 10 or 12 parts of Water, will be found sufficient for slow and gentle action ; for more powerful results, 1 part acid to 8 of water should be used. It should be noted that in making dilute sulphuric acid the strong acid should be poured into the water slowly and gradually. The superiority and convenience of this Battery over all others consists in the little trouble required to put it in action, and the great power obtained. They are not obnoxious or disagreeable during their action, hydrogen only being evolved. One Battery with a piece of platinized silver two inches square, immersed in a tumbler of dilute acid, in]connection with an electro-magnet, will support three hundred- weight. Each. Each. s. d. s. d. 2530 Smee's Batteries, in flat Glass Cells (fig. 2530) . . 12 6 15 6 Set of Six Half-pint Smee's Batteries, in round pots, and a mahogany tray ....... 1 18 6 This set is so arranged, that it can be used for quantity or intensity effects, will show all the leading facts connected with galvanism, decomposing water, deflagrating metals, &c., &c., and is well adapted for the instruction of a small class. Smee's Batteries arranged in an intensity series, and excited with exceedingly weak acid, answer well for ringing signal bells or short telegraph lines, care being taken to keep the zinc plates well amalgamated. 2531 Set of Six one-pint Smee's Batteries, in flat Stoneware cells and mahogany tray (fig. 2531) .... 330 2532 Set of Six two -pint ditto, in ditto 440 2533 Set of Six one-pint ditto, in flat cells and mahogany tray, with counterpoise weights, or ratchet wheel, for suspending the battery when not in use . . . 3 15 550 2534 Smee's Batteries, Intensity Series (fig. 2534) . 550 See also Sections Electric Light and Telegraph. Grove's Batteries, the elements consist of a double plate of amalgamated Zinc, and a single plate of Platinum ; a porous cell separates the metals ; the former being excited by Sulphuric acid and Water (1 part strong sulphuric acid to 8 parts of water), the latter by concentrated Nitric acid. This is the most powerful of all voltaic arrangements, and is the best adapted for brilliant and showy experiments in public institutions, or where a powerful current is required. The action is very uniform for some con- siderable period. A De la Rive's Battery is a modification of Grove's, the Nitric acid being on the exterior in a large glass bottle. A porous cell or tube containing the Zinc and dilute Sulphuric Acid is inserted into the bottle ; this is removed out of the glass bottle (containing the Nitric Acid, and replaced by a Glass stopper when the Battery is not in use ; by this arrangement a large quantity of Acid can be retained ready for iise without the escape of acid fumes. 45, CORffHILL, B.C., AND 122, REGENT STREET, W., LONDON". 431 FIG. 2537. FIG. 2535. Each. a. d. 2535 Grove's Battery, single cell (fig. 2535) . -. . . . . 10 2536 Set of Four Grove's Batteries, with suitable metallic connections, porous cells, and earthenware troughs, in mahogany tray . . . 2 10 2537 Set of Five Grove's Batteries, in tray (fig. 2537) . . . .330 2538 Set of Eight ditto, in mahogany tray . . . ^. .550 2539 Set of Ten ditto, in ditto 660 2540 Grove's Gas Battery, in which the active elements are Hydrogen and Oxygen gases ; set of six gas batteries mounted on a stand . . 6 10 2541 Water Battery, Crosse's, a Voltaic Combination of high intensity. Fitted up to order with any number of pairs of metallic elements, placed in glass or porcelain cells, from 200 to 2000. The apparatus is constructed with due regard to insulation, and, by means of binding-screws, the action of any number in the series may be examined with great convenience, and any cells removed without disturbing others. 2542 Bunsen's Carbon Battery (elements Zinc and Carbon) single cell, shown in section fig. 2542 10 6 2543 Bunsen's Batteries, a series of ten, arranged in a stout wood tray (fig. 2543) 550 The Carbon Batteries are excited by the same acids as Grove's arrangement (strong nitric acid and dilute sulphuric acid, 1 part strong acid to 7 or 8 of water), and will be found next to it in intensity and energy, at a much lower original cost. FIG, 2543. FiG. 2542. 432 NEGEETTI AND ZAMBRA, HOLBOEX VIADUCT, B.C., FIG. 1888. FIG. 2565. Each. a. d. 076 Each. s. d. 10 6 2 15 5 10 2544 Callan's Cast Iron or Maynooth Batteries . . 5s. 2545 Sets of Five and Ten Cast Iron Batteries, full size, in a Stout wood tray The Maynooth Battery is composed of a Cast Iron Cell, a rectangular Porous Pot, and a stout plate of Amalgamated Zinc. The porous cell is charged with Dilute Sulphuric Acid, one part strong acid to eight parts Water, and the Iron Cell with strong Nitric and Sulphuric Acids, with a Saturated Solution of Nitrate of Potash in equal parts. This also is a very powerful form of battery, adapted to exhibit all galvanic phenomena with great brilliancy, and suited for rough Manufacturing or Mining Purposes. Professor Faraday found the efficiency and steady working of Callan's Battery much improved by using equal parts of strong Nitric Acid and strong Sulphuric Acid in the Iron Cell, omitting the Solution of Nitrate of Potash. 2546 A Set of 25 Callan's or Maynooth Batteries, sufficient for producing a very effective Electric Light for private exhibition. In two strong trays 10 10 2547 Walker's Battery is similar to Smee's arrangement; but in place of the Platinized Silver (or Electro Negative Plate) slabs of Gas Graphite or Platinized Graphite are used, the other element being Amalgamated Zinc, the battery, like Smee's, being charged with Dilute Sulphuric Acid. This battery is economical and simple in use, has considerable Electro Motive force, and has been found very serviceable for Railway Telegraph work. Price for Walker's Battery, per cell, about as Smee's Batteries. The Leclanche Cell has now superseded this battery. 2548 Dr. Leeson's Battery is formed of a plate of Copper in a Porous Cell, surrounded by a plate of zinc in a stoneware jar. The Porous Cell is charged with a Solution of Bichromate of Potash, one part of Bichromate to ten parts of Water, the outer jar being charged with Dilute Sulphuric Acid. Price of Dr. Leeson's Batteries same as Daniell's. See page 429. 2549 Sulphate of Lead Battery. Price per Pint Cell . . . .050 2550 Cauterising Batteries, for Amputation, &c., supplied to order . . . . 6 6 to 10 10 See also Section, Medical Instruments The Zinc Plates of Smee's, Grove's, Callan's, Bichromate, Leclanche and Bunsen's Batteries should be examined now and then, and re-amalgamated to pre- vent local action, and it is advisable to thoroughly wash with plenty of clean water all batteries before putting away, after use. 45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 483 BICHROMATE BOTTLE BATTERY. One of the most elegant and convenient forms of galvanic battery yet intro- duced is that shown in our engraving (fig. 2551) ; it is a modification of Dr. Leeson's Bichromate Battery ; the elements are two plates of Graphite or Gas Carbon, and a stout plate of Zinc. The exciting fluid is a saturated solution of Bichromate of Potass (about 2 ounces of bichromate potass to 1 pint of water), with one part by measure of strong Sulphuric Acid to every twelve parts of bichromate solution (nearly two fluid ounces of acid to an imperial pint, or twenty ounces). This acid should be added to the bichromate slowly : when the solution is cold, it is ready for use. It will be seen from the drawing that the glass bottle-shaped cell has a long neck. This is contrived for the purpose of withdrawing the zinc element from the exciting fluid when the battery is not in use, and thus stopping all action or waste. This zinc plate is placed between the two carbon plates, and is only half their length, by a stout wire rod attached to it ; the zinc can be withdrawn from or immersed in the exciting fluid very conveniently, and rapidly sets in action any apparatus connected with it, such as an induction coil, a signal bell, or small telegraphic instrument. Its simplicity, combined with the absence of any fumes or smell, render the Bichromate Battery most useful for short action. The Bichromate Batteries may be combined either for quantity or intensity effects. 2551 Bichromate Bottle Batteries (fig. 2551). Price, each . . 1-pt. 2-pts. 4-pts. 10s. 18s. 6d. 32s. 2552 Bichromate Battery, in round Cell Quart Size (fig. 2552) - . . 16 2553 Fuller's Constant Battery, consists of a Plate of Carbon in an Earthenware Cell, and a Porous Tube in which is placed a Cylinder of Zinc, the lower part being surrounded with Mercury. This Porous Cell is filled with Dilute Sulphuric Acid, 1 part Acid to 8 of Water. The outer Cell is charged with a Solution of Bichromate of Potass with one-fourth its bulk of Sulphuric Acid. Per Cell 086 2554 The Leclanche Battery. The elements in this battery are a cylinder of Carbon, inserted into a round porous tube, closely surrounded by a mixture of small fragments of very pure Peroxide of Manganese and Coke. The top of the mixture in the porous pot is covered with wax. The porous cell and its contents are placed in a glass bottle, as seen in fig 2554, with a rod of Zinc (the Electro Positive element) ; and this glass cell is to be about half -filled with a solution of Chloro- hydrate of Ammonia (the Sal Ammoniac of commerce). The Electromotive force of the Leclanche Cell is stated by Ganottobe -j~j that of a Daniell's Cell, and its resistance about 1^ of a British Association Unit. For durability and cleanliness the Leclanche Cells are unequalled, requiring but a minimum of attention, whilst on the other hand, for cost of working they are the cheapest form of battery that is made, no local action taking place when not in actual use. They may therefore be specially recommended for all classes of intermittent work : the consump- tion of material being in direct proportion to the amount of work performed. For train signalling apparatus, and for ringing bells, these batteries have been found to answer well for long periods of time. The inventor states that the Electromotive Force is 75 per cent, greater than the Daniell Battery, whilst its resistance is 90 per cent, less : and gives the following instructions for charging, which should be carefully attended to. 2 F 434 NEailETTI AND ZAMBRA, 11OLBOEN VIADUCT, K.C., FIG. 2552. FIG. 2551. FIG. 2554. Fill the glass cell about ^ an inch high with powdered Sal Ammoniac ; put the porous cell in its place, and half fill the glass cell with water (say about 2 ounces of the crystal to 1 pint of water) pouring a little water into the porous cell at the same time through the holes in the top. The solution of Sal Ammoniac should always be strong, an excess of salt being kept in the cell. The battery will remain in working order so long as the solution is clear, and in contact with the zinc. When the solution comes turbid or milky, add Sal Ammoniac, and in a few hours the battery will be as powerful as ever. It may be placed aside for months without much deteriorating, but if for a very long period it is best to remove to remove the porous cell. Special care should be taken that the porous cell never stands more than half its height in the liquid. Price for the Leclanche Battery Cells (fig. 2554) Each No. 1, 5s. 6d. ; No. 2, 4s. ; No. 3, Extra iLiincs for above . . . each . Is. 8 006 Chloro-hydrate of Ammonia in Powder . per Ib. 016 2555 Insulated Stand, for exhibiting the combustion of Carbon, fusion of wire, &c., with the Galvanic Battery 150 2556 Insulated Stand, with Henly's Universal Discharger and Press, two pairs of forceps, &c., applicable for both Yoltaic and Frictional Electricity (see ante, page 417, fig. 2408) . . . 2 10 Each. s. d. 036 008 Each. s. d. FIG 25C3*. FIG. 2557. FIG. 2563. 45, CORNHILI., E.G., AND 122, REGENT STREET, W., LONDON. 435 FIG. 2567. FIG. 2572. FIG. 2567*. Each. s. d. 2557 Glass Globe, with Stopcock, brass caps, sliding forceps and balls, for showing Electrical Light in vacua, and decomposing gases by the ignition of Carbon points with the galvanic battery (fig. 2557, see also fig. 2451) . 2558 Lamp, Electric, with self -regulating apparatus for the carbon points 2559 Ditto ditto Duboscq's arrangement . 2560 Decomposition Apparatus, with Single Tube, for collecting the gases combined . . .7s. 6d. 15 2561 Decomposition Apparatus, with single Graduated Tube (fig. 2564) 2562 Apparatus for Decomposing Water (Volta-meter), with double tubes for collecting the Oxygen and Hydrogen gases separate, small size . . . . . . 10 6 2563 Decomposition Apparatus, Double Tubes, larger, suitable for lecture tables (figs. 2563 and 2563*) from 110 2564 Decomposition Apparatus, with Double Tubes graduated into lOths and lOOths of a cubic inch . 1 10 2565 Volta-Meter, with large Platinum Electrodes, divided by a porous diaphragm, for experiments with large and very powerful batteries (fig. 2565) .... 2566 Faraday's Apparatus, for Electrical Chemical Decompo- sitions, consisting of glass trough divided by a diaphragm (figs. 2566, 2566*) 14 6 2567 V and U Tubes for the decomposition of Neutral Salts (figs. 2567, 2567) 050 2568 Pieces of Platinum and Silver Wire soldered together alternately ; a strong voltaic current passed through causes the platinum to become red hot without heating the silver 2569 Apparatus to exhibit the increase of temperature produced by the passage of an electric current through a fine platinum wire enclosed in a glass tube, which prevents radiation, and a much greater length of wire is heated than if it be exposed without the tube 2570 Electro-Thermometer (Harris's) for measuring the Calorific effects of electricity ..... 2571 Aurora Tube for experiments with the tube exhausted of air, or charged with different gases (fig. 2571) . Each. s. d. 330 12 12 13 110 150 16 1 10 220 330 110 10 6 12 6 300 1 18 330 436 NEGRETTI AND ZAMBRA, HOLBORN YIADUCT, B.C., Each. Each. s. (1. s. d. 2572 Model Canon or Bomb, mounted on mahogany stand, with binding screws, &c., for firing Gunpowder by Galvanic Battery (fig. 2572) 110 2573 Model Apparatus for Submarine Explosions. For explaining and exhibiting the method of firing gun- powder or other explosive compounds (Torpedoes) beneath the surface of water, or at long distances, either for Engineering purposes, or for Naval and Military warfare 0156 220 2574 Rectangular Battery Cells, of hard glazed Porcelain, with porous jars, 6-in. high, G^-in. wide, 2-in. thick . 046 2575 Ditto ditto 6-in. high, 4-in. wide, 2-in. thick . 036 2576 Rectangular Battery Cells, 5-in. high, 3-in. wide, l-in. thick ....' 028 2577 Glass Battery Cells, of various dimensions . from 46 2578 Ebonite,ditto from 046 2579 Gutta Percha ditto Acid Holders, various 2580 Platinized Silver for Smee's Battery . . per oz. 12 6 2581 Platinum Foil and Wire of all thicknesses, variable. About per dram 5s. per oz. 1 15 2582 Amalgamated Zinc Plates, cut to various sizes, per Ib. 016 2583 Zinc Rods for Daniell's Batteries, each 8d., or accord- ing to weight 010 014 2584 Galvanic Conducting or Connecting Wires, in pairs, of convenient length for experimental or Medical use, insulated with Cotton or Gutta Percha, various lengths and sizes . . . ' . . from per pair 026 2585 Boxwood Charcoal, for points . . . per oz. 006 2586 Charcoal or Graphite Points, for Electric Light, per pair 010 2587 Carbon or Graphite Battery Plates. Inches 4xl 6xli 6x2 6x3 8x4 12x4 Price 9d. Is. Is. 4d. Is. 8d. 2s. 3s. 6d. 2588 Gold, Silver, Platinum, Brass, Copper, Zinc, Iron,'and Steel Wire and Foil, for combustion, small reels .006 026 2589 A Series of Six Smee's Batteries, in a tray ; apparatus for decomposing water into oxygen and hydrogen ; V tube for decomposing neutral salts, various metal wires and foils for igniting and deflagrating, and a glass trough fitted for depositing metals by the electrotype or electro-gilding process. A small useful set for the use of Schoolmasters, for instructing a class . 3 10 2590 Larger Series, suited for Lecturers . . . .550 660 The following values have been obtained for the Electro-Motive Force of the most useful battery combinations; they are the mean values of many careful determinations : Bunsen's Battery 839 Grove's 829 Smee's ' . . . . . . 210 Wollaston's 208 GANOT. 45, COENHILL, B.C., AND 122, REGENT STREET, W., LONDON. 437 ELECTRIC LIGHT. FIG. 2o% FlG. 2591. IN 1801 the distinguished chemist SIR HUMPHRY DAVY first exhibited, at the Royal Institution of London, a series of brilliant experiments with the Electric Light, by means of a Battery of 2,000 plates, each 4 inches square ; but it was not until the more permanent and powerful batteries of Daniell, Grove, and Bunsen were invented that the light became of any practical use. As an illuminating agent for optical experiment it is invaluable ; and it has been applied to Light-house service, with very considerable success, by Mr. Holmes, at Dungeness on the south-east coast of England, since June, 1862. This light is produced by a powerful Magneto -Electric Apparatus similar to one exhibited in action by Mr. Holmes at the Exhibition of that year. The Apparatus we catalogue in this section is chiefly adapted for private experi- ment and the lecture-room ; but by extending and enlarging the series of batteries an Electric Light can be supplied of sufficient intensity to illuminate a large area, for which special quotations will be given upon application giving particulars of what is required. 2591 2592 2593 2595 2594 A Set of o.Callan's Cast Iron Batteries, in stout wood tray 2595 A Set of 10 ditto ditto in tray . A Set of 5 Grove's Batteries, in strong wood tray (as fig. 2591) A Set of 10 ditto ditto in tray .... A Set of 5 Bunsen's Carbon Batteries, in stout wood tray A Set of 10 ditto ditto in tray .... Each. s. d. 3 3 6 6 2 15 5 5 2 15 5 10 438 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.C., FIG. 2571. Each. B. d. 2596 Self-acting Electric Lamp, arranged on convenient stand (as fig. 2596), with adjustments to the Carbon Points 2 10 2597 Electric Lamp, without adjustments .... 220 2598 Carbon Points or Rods from 016 2599 Parabolic Reflectors, for Electric Light, thickly plated, from each 220 2600 Insulated (Gutta Percha) Copper Wire, 8d. to Is. 4d. per yard, price variable. 2601 Glass Tubes, of large size, for exhibiting the Aurora Borealis; mounted with Stopcock and Metal terminals, for experimenting with various Gases, &c. ; on a firm base (fig. 2571) 330 2602 Electric Lantern, an improved arrangement, having two sets of Condensers. With it the direct ray as well as the Spectrum may be projected upon the same screen without moving the Lantern. A gas jet is placed inside the Lantern, and suitable adjustments are provided for keeping the Carbon Points uniform in height. Price in the most complete form (fig. 2602) 25 45 Cells of Bunsen's Batteries are required for effectively working the Electric Light, or 45 Cells of Grove's Batteries; Price for 40 Bunsen's 20; 45 Grove's, 23. For further particulars respecting Batteries, &c., see pages 428 to 432. 45, COBNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 439 FIG/ 2 603. 2603 Electric Light Apparatus (fig. 2603) consisting of a Six Cell Grove VBattery with connections and conducting wires. Electric Lamp with Carbon Points ; Parabolic Reflector having suitable adjusting and | clamping Screws, the Carbon Points being regulated by an Electric Magnet. Price for the complete Apparatus 6 10 2604 Dynamo Magneto Electric Machine (fig. 2604). This machine can be used for a variety of experi- mental purposes, as a substitute for the Yoltaic Battery : it will heat to incandescence 12 inches of Platinum wire, '01 diameter, or can be arranged to rapidly decompose water .... 28 2605 Dynamo Magneto Electric Machine, requiring ^ Horse Power ; can be driven either by Steam or Gas Engine to light five 20-Candle Power Incandescent Lamps 15 10 2606 Ditto ditto to light twenty 20-Candle Power Lamps, requiring 3 Horse-power Engines 50 Fm. 2604. The above prices do not include either Steam or Gas Engines. For the price of Steam Engines and Gas Engines see Mechanical Section at the end of the Book. Estimates for larger Dynamos and Engines supplied upon application stating the requirements. 440 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.C., FIG. 2608. Flo. 2609. FIG. 2610. ELEOTRIC-META LLURGIC AL APPARATUS. ELECTROTYPE APPARATUS IS NOW EXTENSIVELY USED FOR OBTAINING BY GALVANISM EXACT FAC-SIMILES OF ENGRAVED COPPER PLATES, WOOD ENGRAVINGS, MEDALS, PLASTER CASTS, ELECTRO GILDING AND PLATING, ETC. 2607 Eacb. s. Each. s. d. 016 026 2608 Electrotype Apparatus, consisting of earthenware jar, with porous pot, zinc and wire (fig. 2607) . Bound Glazed Stoneware Troughs, not permeable to sulphate of copper, with porous cell, zinc plate, binding screw and wire, suitable for copying medals, seals, plaster casts, &c. (fig. 2608) . . 5s. 6d. 7 6 10 6 This apparatus is most convenient and simple in its operation, and particularly adapted for those commencing to practise this interesting and useful art. 2609 Electrotype Apparatus (fig. 2609) very convenient for copying small seals, medals, &c. . . . . . 15 Electrotype Trough, square, with flat porous cell, zinc plate and binding screw, and brass bars, on which to suspend the object to be copied (fig. 2610) . 16 Electrotype Trough, as No. 2610, smaller size . 12 6 2610 2611 FIG. 2613. FIG. 2615. 45, CORNHILL, E.G., AND 122, EBGENT STREET, W., LONDON. 441 Fi. 2619. Each. s. d. Each. s. d. s. d 2612 Single Smee's Battery, with Precipitating Trough, for making a number of small medals . . from 1 10 2613 Larger ditto (fig. 2613) 220 2614 Electrotype Precipitating Trough, large sized oval shape, with brass connecting bars (fig. 2614) . 1 16 2615 Vertical Precipitating Trough, with Smee's battery, for (obtaining duplicates of large engraved Copper Plates, Maps, &c. (fig. 2615) . . . . .220 3 10 2616 Single Cell Apparatus, for Electro-gilding or Plating (fig. 2616) 10 6 FIG. 2614. FIG. 2616. 2617 Electro -Gilding and Plating Apparatus by the Battery Process, with Glass precipitating trough, and one Smee's battery ...... 2618 Electro -Gilding and Plating Apparatus, with 2 Smee's batteries ......... 2619 Ditto ditto with 3 Smee's batteries (fig. 2619) . 2620 Apparatus for coating metallic surfaces with Aluminium and Silicium from 2621 Apparatus for Nickel Plating fitted up to order. 18 6 1 10 200 10 6 442 NEGRETTl AND ZAMBRA, HOLBOKN VIADUCT, E.G., H J FIG. 2623. Each. s. d. Each. s. d. 11 2641 Is. 8d. and 2s. 5 3 Height . Price Porous Cells, Height . Width . Price . .' 2 4d!' Flat 2-in 8 a , OOiiXllSLL, K.C., AND 122, KEGENT STEEET, W., LONDON. 453 FiG. 2745. 2752 Gassiot's Revolving Star, best form .... 550 This apparatus is an adaptation of Sturgeon's Revolving Electrical Spiral. Attached to the axis of the machine is a piece of varnished wood or vulcanite, fitted at each end with metallic spring clips for holding securely the vacuum tube to be revolved. Two fine insulated wires in connection with the metal clips and terminal wires of the vacuum tube are carried down the back of the wood arm to the axis, and are in metallic connection with two binding screws on the base of the apparatus by which the induction coil is to be placed in contact. The connections having been carefully made, the tube is caused to be very rapidly revolved by the action of the large wheel on a small one placed at the axis, and the result is a beautifully iridescent star, the colours. &c., varying with the form of the tube employed. 2754 Vacuum Tubes for Medical use, illuminating the Throat, Ear, &c., various forms and prices, supplied to order. 2755 Incandescent Lamps, 2|, 5, 10, 20 C. P. . each 2756 Ditto ditto, for Microscopic use 2757 Holders, for ditto 2758 Ditto with Bracket Clip 2759 Miniature Lamps for Scarf Pins, &c. . . each 2760 Portable Accumulator, containing 3 Ebonite Cells, weight about 2 Ibs. ....... 2761 Ditto ditto with Lamp and Comb to wear in the hair 2762 Apparatus for exhibiting the Luminous Electric discharge in vacuo, (Aurora Borealis) (fig. 2762) from Carbon Points on Metal Terminals, sometimes called the Electrical Egg 330 s. 6 5 2 4 10 200 330 454 NEGRETTI AND ZAMBEA, HOLBORN VIADUCT, E.G., FIG. 2767. FIG. 2762, 2763 Glass Tube for similar experiments, fitted -with a Stop-Cock, various lengths (see page 438) . from 2764 Ditto ditto of Uranium glass . . from 2765 Eudiometer, for use with Inductorium . 2766 Uranium Glass Vessel, for showing Fluorescence from 2767 Whirling Apparatus for Gassiot's Star, for large sized Vacuum tubes (fig. 2767) 2767* Revolving Colour Disc, for use with No. 2767, exhibiting white light, and proving that the induction spark is not continuous .... Each. s. d. 220 440 076 10 6 4 12 10 6 FIG. 27 6 J. 2768 Wheatstone's Rheostat, for adjusting and regulating an electric current so as to obtain any constant degree of force ........ 2769 Wheatstone's Rheostat, for ascertaining the amount of resistance offered by various lengths of wire to a given current of electricity (fig. 2769) 2770 Wheatstone's Apparatus, for determining the Differential Resistance of various metal wires, &c. &c. 440 550 2 10 45, COBNH1LL, E.G., AND 122, REGENT STREET, W., LONDON. 2771 Conducting Wires, covered with Cotton, various lengths 2772 Ditto ditto coated with Gutta Percha .... 455 036 050 Table of relative lengths and weights of Copper Wire, covered with Cotton, as used for Electric, Galvanic, Electro-magnetic, and Telegraphic purposes : Nos. 6. 9. 12. 14. 18. 23. 32. 34. Feet 8 18 39 48 130 360 1,300 2,000 to the Ib. weight. For the price, which is variable, see pages 449 and 459, No. 2717. ELECTRO-GALVANIC MACHINES FOR ADMINISTERING MEDICAL GALVANISM. FIG. 2773. THE scientific application of Electricity to medicine has made less progress than the success which has really, in many cases, attended its use, might have been justly expected to produce. It appears, from every trial of its powers hitherto made, that, under judicious management, its application has never been known to produce consequences decidedly injurious, while in many of the most distressing disorders, it has frequently been of considerable service. These are powerful recommendations ; and when it is added that it is an external and by no means a painful remedy, and that it may be applied immediately to the affected part, without interfering with any other organ, its advantages must appear to be considerable. At the same time'^it must be remembered, that it is a remedy of such a nature, that often a long con- tinuance of its application is in many cases necessary before any decided and beneficial results can be obtained. s. d 2773 Electro -Galvanic Coil Machines for Medical use, with four binding screws, to regulate the intensity of the shock, Nos. 1 and 2 being the lowest in strength, 1 and 3 the medium, and 1 and 4 the full power of current (Coil as shown in fig. 2773) .... 1 10 2774 Electro -Galvanic Coil Machines, with Lockey's Water Regulator, a very elegant method of controlling the force of the current, but perhaps not quite so definite as the previous arrangement (fig. 2774) ... 1 10 C 456 NEGRETTI AND ZAMBRA, HOLBOEN VIADUCT, B.C., FIG. 2778. FIG. 2774. 2775 Electro -Galvanic Coil Machines, either with the Four regulating Binding Screws, or the Lockey's Water Regulator, packed in polished Mahogany case, with one of Smee's Batteries, Conducting Wires, and Shock Handles, complete, very portable and convenient for; medical practice . 330 2776 Electro -Galvanic Coil Machine, with two Smee's Batteries, in Mahogany case, &c 440 2778 Electro -Galvanic Coil Machine, larger and most improved form, with a simple and effective Lever contrivance for regulating the shock, complete, in mahogany case, with [two large Smee's Batteries, flexible Conducting Wires, Shock Handles, Directors, &c., with directions for use (fig. 2778) 660 880 2779 Larger Coils and Batteries fitted to above, for Hospital use, made to order. These instruments can be had of either Primary or Secondary arrangement or both combined in one coil. D E F 2780 Yarious forms of Directors for use with Electrical Apparatus. Full instructions sent with each apparatus, that will enable patients to use them with the greatest eas and convenience. 45, CORNHILL, E.G., AND 122, BEGENT STREET, W., LONDON. 457 Each. a. 2780* Sponge Directors for the hands (fig. c) from, per pair Ditto ditto Flat, large surface (fig. F) Shock Handles, plain tubes and wires . . . Curved and Bent Directors (or Rheophores), for the internal application of Electricity (figs. A & B) . Flat and Curved Surface Director (figs. D & E) . FIG. 2781. 2781 . Faraday's Wire Brush Directors with wood handles (fig. 2781) . . Each. a. d. 046 08 02 10 6 056 076 056 FIG. 2782. 2782~Pocket Medical Induction Coil (fig. 2782). In this apparatus the electro- motor used is Pile Marie Davy, a voltaic battery having bi-sulphate of mercury and carbon electrodes. The cell of this battery is made of vulcanite in the form of a tray about If -inch square, and by 1-inch deep ; into this tray is placed a slab of graphite, and above it a piece of zinc. Metal fittings are attached to the cell to connect the elements to the coil. To charge the battery, a small quantity of Bi-Sulphate of Mercury is placed on the Carbon, which is to be saturated with water, and then have the zinc plate placed upon it, observing that the zinc does not in any way touch the carbon. The battery will now be in action, and the vibrating contact break should be adjusted until steady vibrations are obtained. At the side of the box will be found metallic fittings, by which shock handles or directors are to be connected, and the current of electricity conveyed to any part of the person to be operated upon. The strength of the current is regulated by a brass tube, covering the bundle of iron wire in the centre of the coil. When this brass tube entirely covers the iron wire, the action of the coil is very feeble, but when it is fully drawn out, and the bundle quite uncovered, the maximum amount of power is obtained. 458 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., It is requisite frequently to clean out the battery when in constant use; this is simply done by washing in plenty of water the cell, carbon, and zinc (to remove all the yellow deposit), and then replace the elements, with a fresh charge of Bi-Sulphate of Mercury. In handling this prepar- ation great care should be taken to prevent it coming in contact with any gold or silver articles, as the mercury would amalgamate with these metals, and be very troublesome to remove ; in fact, delicate jewellery would be utterly spoilt. Various shock handles and directors and flexible wires for applying the galvanic current are supplied with each instrument. 2783 Portable Medical Induction Coil (fig. 2782) . . . . 440 2784 Cruikshank's Battery (see fig. 2519, page 428), for Medical use, where it is desirable to use the actual current without the interruption of a coil 1 12 2785 Induction Coil Apparatus, large size, similar to above, with Chloride of Silver and Zinc ; Battery, for Hospital use 6 10 2786 Galvanic Cautery Battery, improved arrangement in Box, complete with Ecraseur, having Curved and Straight ends, Platinum Wire, &c., 12 12 HINTS FOR APPLYING MEDICAL GALVANISM.* 2787 "1. Feeble powers should always be first tried; these should be gradually augmented, and the use of such finally persisted in, as, without producing any violent effects, appear to make a decided impression on the disease. " 2. Galvanism, as a remedial agent, must not be hastily given up because of its beneficial effects not immediately appearing, for these, generally speaking, require considerable time to be developed. " 3. Electricity or Galvanism should not be relied on exclusively in the treat- ment of diseases, but should rather be considered as auxiliary to other methods of cure. """: " 4. To the preceding we shall add, that in cases where the continuous current may be deemed most advisable, it would be well to use batteries composed of plates having an extended surface, there being reason to believe that the curative influence of galvanism in this form depends, not upon its intensity, but upon the quantity of it set in motion." To these principles we may add, that in all cases where it is necessary that the interrupted current should be administered, the electro-magnetic coil machine will be found much more manageable, much more portable, and equally powerful, if not more so than the galvanic battery itself ; but in cases where the continuous current is required, the battery alone should be used. Sig. Orrioli (an Italian Philosopher) recommends that before attempting to apply Electricity therapeutically, we should study the nature of the secretions produced, in order that we may be enabled to create in the secretory organ a proper electrical state for bringing about contrary effects. These secretions will be Acid, Alkaline, or Neutral. If they be acid or alkaline no difficulty will exist ; if they are neutral, we should apply to the affected part the pole of the battery opposed to that electrical state which belongs to the normal condition of this part. * G. T. Fisher's Medical Electricity. 45, CORNHILL, E.C., AND 122, EEGENT STREET, W., LONDON. 459 FIG. 2792. MAGNETO ELECTRIC MACHINES. 2788 Our wood-cut, No. 2792, exhibits the modern improved form of Magneto Machine, specially arranged for Medical Purposes. This armature is rotated by a winch handle, setting up an induced current of electricity in the armature, this current being conducted to the patient by convenient flexible wires and directors or shock handles. The strength or force of the current is regulated by the removal of the sof c iron keeper entirely from the end or poles of the magnet, or gradually bringing it closer to the magnet, the most powerful action being obtained when the keeper is entirely removed, and the lowest action when the keeper is in close contact with the magnet. 2789 Negretti and Zambia's Improved Magneto Electro Machine, a most con- venient and portable apparatus for the application of Medical Galvanism ; no acid required, the instrument always ready for use, and the strength of the currents can be regulated from the most feeble to the highest intensity. Price, in strong Pine box, with directors ... 150 2790 Ditto ditto, in Mahogany 1 10 220 2791 Ditto ditto, small pocket size, in Mahogany Box . 260 2792 Magneto Electro Machines, best finish, and Mahogany box (fig. 2792) 2 10 2793 Ditto with Double Magnet 300 2794 Ditto ditto, best finish, in Box, with drawer underneath containing 6 directors for the Face, Spine, Teeth, Ear, &c., and 1 pair of Shock Handles 3 10 2795 Ditto ditto, with external Dial Regulator . 3 15 2796 Electric Colliery Signal Bells, in Dust Proof Boxes. Price each 5-inch. 6-lnch. 7-inch. 8-inch. 75s. 80s. 96s. 120s. 2797 Pushes for ringing Colliery Signal Bells, 12s. 6d. each. 2798 Presselles, Press Buttons or Pushes, and Indicators, for use with Electric Signal Bells for household and other purposes, of various forms and patterns. See page 464. 2799 Gutta Percha Insulated Wire, suitable for Colliery work, various sizes, 9 10s. to 19 10s. per English mile. 460 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., (SI (51 METALLIC THERMOMETER'S ELECTRICAL ALARM. 2800 The engraving (fig. 2800) shows the general arrangement of the Metallic Alarm Thermometer, designed for regulating the temperature in incubating houses- hot-houses, green-houses, drying stores or rooms, hospital or prison wards, &c- They are also valuable as a fire-alarm, either in large buildings or warehouses or on board of ship, and they will notify any change of temperature taking place where the dial A is placed to almost any distance that may be desired. The construction and action of the Alarm ia as follows. At the back of the dial A is fixed a coiled metal spring, in such a manner that it is very sensitive to any changes of temperature, it being lengthened by increased heat, and shortened by cold : these movements are shown by an index in front of the dial A, which has upon it a scale graduated into degrees corresponding to a Thermometer either of Fahrenheit's, Centigrade, or Reaumur, as may be desired. On the glass cover of the dial are mounted two movable indices, in such a way that they can be turned round to any two points of the divided circle, and there fixed ; these two hands represent the highest and lowest temperature required to be notified, the central or moving hand being in connection, by means of a metallic wire, with one pole of a galvanic battery B, and the other two indices being connected by another wire to the other pole of the battery c. Now, should the temperature of the atmosphere surrounding the dial alter, the central hand will be moved either to the right or left, and the moment it touches either of the outer hands, contact will be made, and the galvanic circuit completed, causing the Bell to ring, and give notice to the watchman that the temperature of the building or vessel has undergone some alteration and requires attention. The dial A may be fixed at any distance from the Alarm Bell B, dependent only on the amount of battery power used, one battery being sufficient to work the apparatus between any two portions of an ordinary sized building. Price of Dial, Alarm Bell, and 1 Battery (tig. 2800) . .550 45, COENHILL,|E.C., AND 122, BEGENT STEEET, w., LONDON. ^ttitf^ 461 FIG. 2801. FIG. 2801*. ELECTRIC TELEGRAPH APPARATUS. 2801 Model Telegraph Instruments, consisting of two Single Needle Instruments with Signal Bells and communicators, for exhibiting and explaining telegraphic communication (figs. 2801 and 2801*). These instruments will be found useful to learners of Telegraphy, The complete Set of two Needle Instruments with Bells attached 5 10 Leclanche Batteries for working the above through short distances, Single Cells, see also page 8s. 6d. and 10s. 6d. each. Six-Cell Smee's Batteries (fig. 2803), for Telegraph use, conveniently arranged in a stout framed tray, with Ratchet Movement for immersing the elements to any desired depth in the acid according to the action required, or for entirely withdrawing them when out of use . . Price 4 10 Smee's Batteries when charged with extremely dilute acid will be found to act very well for some considerable time without much attention. For particulars of Leclanche and other Batteries, see pages 428 to 434. 2802 2803 FIG. 2804. FIG. 2806. 2804 Portable Sick Room and Invalid's Electrical Bell and Battery combined, in a mahogany case, for temporary service. Specially adapted for the use of invalids, with 30 yards of flexible Wire Cord and Presselle, &c. (fig. 2804) 440 462 XEGRETTI AND ZAMBEA, HOLBOEN VIADUCT, E.C., 2805 Electrical Indicating Signal Bell (fig. 2805). When the alarm is put into action by the electrical current a revolving disc is moved, pointing out to the observer the particular bell that has been sounded : where several bells are in use at a station this is an important addition to the instrument. Price 220 These Bells can be very economically fitted up in connection with one or more of the Leclanche or Bichromate Bottle Batteries (figs. 2551 and 2554). A simple immersion of the elements of the Bichromate Battery in the solution for a second, being sufficient to ring a bell to a considerable distance. The Leclanche has, however, been found the most useful form of battery for this work ; it being most simple and cleanly in use (no strong or corrosive acid being required), and the elements remain unimpaired for a very long period. See description, page 433. 2806 NEGRETTI AND ZAMBBA'S ELECTRIC THERMOMETER, Which will indicate, by ringing a Bell, when the Temperature in a Greenhouse falls below or rises above the point at which injury would be caused to plants, &c. ? the Thermometer being placed in the Greenhouse, and the Bell in the gardener's cottage, or at any other convenient spot. It also indicates present temperature, as, an ordinary Thermometer, and can be used as an efficient Fire Alarm in Warehouses or in Private Dwellings. Price, including Bell, Battery, Thermometer, and 50 feet of Double Connecting Wire (fig. 2806) 1 10 Extra Double Wire, 2d. per Yard. These Thermometers can be constructed to ring a bell at two or more different Temperatures, should such be required, at a slightly increased cost. ELECTRIC BELLS. 2807 Electric Bells, on Polished Mahogany Mounting, horizontal or vertical action. For general House or Telegraph use (fig. 2807). Trembling. Bell 2 in. each 10s. 3 12s. 16s. 21s. 28s. e stroke. ,ch 9s. 12s. 15s. 20s. 27s. 32s, Continuous ringing. each 10s. 6d. 12s. 15s. , 20s. 28s. 32s. Estimates given for Telegraph or Household Signal Bells, Electrical Alarm Apparatus, fittings, &c., upon receipt of particulars. 45, CORN HILL, B.C., AND 122, REGENT STREET, W., LONDON. 463 FIG. 2805. FIG. 2807. FIG. 2808. 2808 Magneto Electro Exploder, improved arrangement, in mahogany case, for firing Mines or Cannon by Electro-Magnetism; price according to the number of charges to be fired (fig. 2808) . . 12 12s. to 26 2809 Fuses, for use with the Exploder, Experimental, Mining, Blasting, Cannon and Submarine, supplied to order . . from, per dozen 5s. to 10s. 2810 Induction Coils, specially arranged for blasting purposes, where a number of charges are required to be fired simultaneously, in stout case . 13 2811 Copper Wire, insulated with Gutta Percha, for use with above, per 100 yards. Price variable, from 1 Is. For Prices of Copper Wire covered with Cotton and Silk, see ante, page 455. 2812 Vertical Action Electric Bell, (fig. 2807), either trembling or single stroke, same price as horizontal action . . . . . 2813 Electric " House " Bell, specially arranged as an efficient House or Warehouse Bell, with 3-inch loud tone G-ong, nickel plated, in polished case, or fitted with continuous ringing action for Burglar and Fire Alarm each ( 12 6 464 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, B.C. 2815 2816 2817 2818 2819 2820 2821 FIG. 2427. 2814 Plained Turned Hard Wood Pushes Each. s. d. . Is., Is. 6d., 2s. 6d. 036 FIG. 2396. FIG. 2389. Porcelain Ornamental Pushes, for indoor use, various, each 2s., 2s. 6d., to 5s. and Ornamental Brass Pushes, for external use each 5s. 6d., 6s. Complete Electric Bell Sets, consisting of Bell, Battery, Wire and Push, ready for fixing. 2| in. Bell 2 in. Push 1 Leclanche Cell 25 yds. Wire 3 3 2 Leclanch^ Cells 30 H > 3 > 40 ,, Indicators, as shown in fig. 2822, for houses or hotels, in polished mahogany cases for 6 Nos per No. 12 6 Switches, Contacts, Fire Alarms, Walnut or Mahogany, one way Switch 2-way 3s., 3-way 4s. 6d., 4-way . . . .6s. 6d. 10 6 Floor Contacts 2s., Door Triggers 030 Sash or Door Contacts, for Burglar Alarms, &c. . each 3s. and 046 6 12 10 16 1 1 DIRECTIONS FOR CONNECTING AND FIXING ELECTRIC BELLS. Fig. 1 represents a single " Circuit," in which one Bell, Push and Battery is employed. A wire is carried from the Carbon Pole of the Battery to the Push, from the Push to the Bell, and from the Bell direct to the Zinc Pole of Battery. Fig. 2 represents manner of enabling the same Bell to be rung from two distinct places. The wire from Carbon Pole is carried to each Push by making a junction, as shown in the diagram, and then carried from each Push to the Bell, as shown by the dotted lines. On pressing the Push the Bell will ring. FIG, 2. FIG. 1. 45, COENHILL, B.C., AND 122, REGENT STREET, W., LONDON. 465 FIG. 2822. 2822 Diagram fig. 2822, showing how to connect up a number of Pushes to Indicator, BeU and Battery, one Wire from Battery to Bell. One wire from each Push to the corresponding terminal on the Indicator Fra'me. One Wire from the Bell to return terminal on the Indicator. One main wire from the Battery, to which one wire from each Push is to^be connected. CONNECTION OF . CELLS LECLANCHE BATTERIES. SMEE'S BATTERIES. INSTRUCTIONS FOB CHARGING THE LECLANCHE BATTERY. 2823 Place the Sal-ammoniac sent, in the glass jar of Battery, and then add water to about three-parts fill the jar. Allow to stand for ten hours before use. When the Battery becomes weak, fresh Sal-ammoniac and water should be used. See also page 434. 2824 Clock, arranged with Electric Alarum, to ring a Bell or Bells at any distance away. Price, with superior Clock 330 Electric Bell and Battery, for use with above . . . .110 Conducting Wire covered with Gutta Percha, for use with above, specially suited for out-of-door use per 100 yards 10 6 2825 Time Clocks, for Factory, to ring automatically at various working hours. The times can be altered when required. Price of best London made Clock 10 10 12 12 Price of Bells, Connections, Wire, &c., as may be required. Estimates supplied. 466 NEGRETTI AND ZAMBRA, HOLBOEN TIADFCT, E.C., Ordinary form of A B C Telegraph, with Bell (fig. 2826). SIR C. WHEATSTONE'S PATENT ALPHABETICAL MAGNETO ELECTRIC TELEGRAPHS. NEGRETTI AND ZAMBRA, AGENTS. 2826 WHEATSTONE'S Instrument is a perfected modification of the original Alphabetic Telegraph, invented and patented by him in 1840, the first step-by-step telegraph instrument ever constructed. Any person able to read is able to manipulate this instrument. The operator has merely to touch in succession, with the fingers of one hand, the keys corre- sponding with the letters forming the message he wishes to transmit, whilst he turns the handle with the other hand. In order to receive a message the operator has only to watch the letters pointed to by the hand of the indicator. The corre- spondence can be carried on at about twenty words per minute. The electric currents which actuate this instrument are produced by the employment of a permanent magnet instead of a voltaic battery ; so that chemical preparations are not required, and the instrument is therefore ready to be put in action at any moment, at whatever distant place it may be removed to, and notwith- standing however long it may have been in disuse. In the absence of voltaic batteries and of working contacts, and in the applica- tion of finger keys, consists the essential superiority of these over all the other ABC instruments which have been hitherto introduced. Fig. 2826 shows the ordinary arrangement for use on private lines. Complete Telegraph for one Station, consisting of Communi- cator and Indicator Alarm Bell, to work with the above Telegraph .... Communicator separately Indicator separately . 21 400 14 700 (45, CORNHILL, E.G., AND 122, EEGENT ST11EET, W., LONDON. 467 FIG. 2827. 2827 Patent Magnetic Counter. This instrument has been devised for the purpose of counting and registering the periodical movements of any machine, whether rotary or reciprocating. It may be applied either near to or at any distance ; it is less cumbrous than mechanical registeis. No battery is employed, the electric currents being produced by a small armature of soft iron oscillating before the poles of a permanent magnet. The Magnetic Counters are made to count to 1,000,000 990 10,000,000 10 10 2828 2829 2830 2831 FIG. 2828. Complete Military Telegraph, in strong oak or mahogany case, with flush metal fastenings, suited for Field Service (fig. 2829) Alarm Bell, in oak or mahogany case for use with above . Complete Apparatus for the Duplex System, by which these instruments may be worked in opposite directions simultaneously through a single wire. For the Double set from Switch on Mahogany Slab 5 5 10 2n2 468 NEGEETTI AND ZAMBEA, HOLBOEN VIADUCT, E.G., FIG. 2832. PNEUMATICS, HYDRAULICS, AND HYDROSTATICS. PNEUMATIC APPARATUS, 2832 Improved Double-Barrel Air Pump, as No 2832, combined with a Third Cylinder on Tate's principle for obtaining the most perfect exhaustion possible, the large vertical cylinders being used for rapidly exhausting any receiver, and the horizontal cylinder for completing the exhaustion to the most extreme point . 17 10 Our engraving (fig. 2832) at the head of this section represents the most improved arrangement of Air Pump yet constructed. With this instrument very large receivers are rapidly exhausted in the usual manner, until the mercury in the gauge falls to -inch of the scale, when further exhaustion is obtained by using the Tate's pump placed at the side of the larger cylinders. At a temperature of 60 degrees of Fahrenheit an exhaustion as low as ^th of an inch may be produced, and when the pump is in very perfect action, and the temperature very low, greater exhaustion may be obtained. 2833 Largest Size Double-Barrel Air Pump, on strong Mahogany Stool Stand, barometer gauge and cistern, with graduated scale divided to inches and tenths, Gun Metal ground receiver plate, or ground Plate Glass, 23-inches diameter, key and lever . . . 36 45, COENHILL, E.G., AND 122, REGENT STREET, W., LONDON. 469 FIG. 2857. FIG. 2835. Pump with 2834 Large Size Double-Barrel Table [Air 11-inch plate, either of accurately-turned Gun Metal, or Ground Plate Glass, mounted on a stout Mahogany Stool Stand, with barometer gauge and graduated scale divided to inches and tenths 2835 Ditto ditto (fig. 2835), (Davenport's arrangement) with mercurial gauge, raised receiver plate, 8 inches diameter, Mahogany Mounting, brass clamp for fastening the pump to the table, and brass spanner . s. d. 25 12 12 FIG. 2843. FIG. 2838. FIG. 2844. 2836 Double-Barrel Table Air Pump, second size ditto 2837 Ditto, third size, with receiver plate, on stand, with gauge 2838 Ditto ditto, without gauge (fig. 2838) 2839 Ditto, fourth size 2840 Ditto, small size 11 10 8 10 7 10 5 4 470 NEGRETTI AND ZAMBRA, HOLBORN YIADUCT, B.C., 2841 2842 2843 2844 2845 2846 2847 FIG. 2849. FIG. 2848. Newman's Improved Single-Barrel Air Pump, for s . a. s. a. obtaining a most perfect exhaustion (Council Medal awarded, 1851) of large size, with metal valves, and Ground Glass Receiver Plate, 13 inches square, Mahogany Stool Stand . ... 40 For description of this Instrument see Catalogue of 1851 Exhibition. 150 2 10 330 076 10 6 066 12 6 Single -Barrel Air Pump, with Receiver . Ditto ditto larger (fig. 2843) Ditto ditto with inclined barrel, raised plate and stopcock (fig. 2844) Cylindrical Glass Receivers, closed at the top for single-barrel air pujips ... 3s. 6d., 5s. Glass Receivers, open at top with ground welts, as fig. 2346 ; see also Nos 2899 to 2905, page 476. Tate's Double -Action Air Pump, having 2 pistons in one cylinder, the air being drawn from the receiver in the middle of the cylinder, and expelled at the two ends. It is mounted on a strong metal clamp and screw, by which it can be firmly attached to any bench or table. The receiver plate is 7 inches diameter, carefully ground ; the cylinder is 16 inches long, with 1^-inch bore length of stroke Si-inches. The exhausting power of this pump is very great, and it has a very simple contrivance, by which it can be also used for condensing. Its compact form renders this pump one of the most handy and useful for laboratory purposes. Price, including Syphon Gauge and fittings, without the Receiver 440 45, COENHILL, B.C., AND 122, REGENT STREET, W., LONDON. 471 FlG. 2850. FIG. 2868. FIG. 2872. FIG. 2869. FIG. 2852. 2848 Tate's Double-Action Air Pump, with large cylinder, and very firm and strong metal mountings, complete (fig. 2848) . . . . 990 2849 Sprengel's Air Pump, constructed on the principle of converting the space to be [exhausted into a Torricellian Vacuum ; it may thus briefly be described : If a small hole be made in the top of a barometer tube, the mercury sinks and draws in air ; if the experiment be so arranged as to allow air to enter along with mercury, and the supply of air is limited, while that of the mercury is unlimited, the air will be carried away, and a vacuum produced. The apparatus is chiefly composed of glass tubes, and is of such a nature that it can hardly be offered for sale, but must be arranged to meet the requirements of the operator. It has been much used in preparing G-eissler's Vacuum Tubes, and will be found fully described in Ganot's Work on Physical Science. Supplied to Order. 2850 Exhausting Syringes (fig. 2850) 8 6 10 6 2851 Condensing Syringes 086 0106 2852 Condensing and Exhausting Syringes, both in one instrument (fig. 2852) 16 2853 Condensing and Exhausting Syringes, of large size . 1 10 2954 Condensing Pumps, large, with Metal Valves . .440 660 2855 Single Transferor (fig. 2855) 16 2856 Double Transferrer (fig. 2856) 220 2857 Vacuum or Pressure Gauge, small, for attaching to Pneumatic Apparatus (fig. 2857). See also Gauges, page 196) 056 076 2858 Flat Brass Plate, ground for open receivers, with collar of leather and sliding wire (fig. 2858) . . . 15 150 2859 Brass Syringe or Pocket Condenser, for producing Heat and Light by rapid compression of air within the Brass Cylinder (fig. 2859) 056 086 2860 Syringe and Lead Weight, with ground glass plate for open receiver . . . . . . . . 10 6 15 2861 Glass Globe and Stop -cock (very light), for proving the density or weight of air and gases (fig. 2861) . . 12 6 15 2862 Copper Bottle, Scale Beam and Stand, with balance weight, for weighing air (fig. 2862) .... 330 472 NEGRETTI AND ZAMBRA, HOLBOBN TIADUOT, B.C., FIG. 2881. FIG. 2874. FIG. 2882. Each. s. d. Each. s. d. 3 15 076 12 6 2863 Scale Beam and Stand, fitted with a light Glass Vessel graduated in Cubic Inches, by which a number of most instructive experiments can be exhibited, illus- trating the specific gravity or weight of various fluids and gases ..... .... 2864 Filtering Cup, with ground Brass Plate, for. showing the porosity of wood, without receiver (fig. 2864) . 2865 Fruit or Taper Stand, for supporting shrivelled fruit, &c., under the receiver of an air pump ... 036 2866 Fountain in Vacuo (fig. 2855) ..... .076 0150 2867 Tall Fountain Glasses ....... 10 6 Bladder Glass (fig. 2868) ...... 036 050 Hand Glass (fig. 2869) ....... 020 040 2870 Bell Experiment, illustrating that air is essential to sound (fig. 2870) ........ 10 6 2871 Ditto, best make, with a ratchet motion (fig. 2871) . 186 2871* Bell Experiment, fitted with electro-magnetic break for ringing the bell by a galvanic battery ... 330 2872 Madgeburg Hemispheres (fig. 2872), the invention of Otto de Guericke (1654), for illustrating the pressure of the atmosphere : Small, 16s. Second size, 18s. Third size, 30s. 2873 Torricellian Experiment, for illustrating the pressure of the atmosphere and construction of the barometer, simple form ..... 15 6 2874 Ditto ditto larger, with graduated tube, best mounting and receiver, &c. (fig. 2874) ........... 220 At pages 2 and 3 will be found a full description of Torricelli's celebrated experiment, and also the construction of Standard Barometers. 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON, 473 FIG. 2825. FIG. 2876. FIG. 2879. FIG. 2878. FlG. 2886. s. a. 2875 Student's or Laboratory Standard Barometer . 550 2876 Observatory Standard Barometers, with mounting board (fig. 2876) See also pages 4 and 5. . . 8 8 10 10 2877 Guinea and Feather Apparatus, 3 falls .... 1 10 2878 Ditto ditto 2 falls (fig. 2878) without the glass receiver 18 6 2879 Guinea and Feather Tube to demonstrate the law that In a vacuum all bodies fall with equal velocity (fig. 2879) 1 16 2880 Model, for showing the principle of the common water pump 150 2881 Model, for ditto, with glass barrel (fig. 2881), without the stand 1 12 6 2882 Model of Forcing Pump (fig. 2882), ditto . ' 2 15 2883 Models of Lifting and Forcing Pumps, mounted on mahogany stands, with water cistern . 550 2884 Model to illustrate the arrangement and construction of Manual Fire Engines 660 2885 The Baroscope, an apparatus consisting of balance beam on a stand, a ball of cork suspended at one end, and a metal weight at the other, illustrating that two bodies balanced in the atmosphere are not so in a vacuum (fig. 2885) 15 474 NEGEETTI AND ZAMBRA, HOLBORN VIADUCT, B.C.. FIG. 2870. FlG. 2893. Each. Each. 2886 Windmills or Fans, of a superior construction, with shifting vanes to show the resistance of air (fig . 2886) from 2887 Four Barometer Tubes, for showing the upward, down- ward, oblique, and lateral pressure of the atmosphere 2887* Leslie's Apparatus for Freezing Water by evaporation under an exhausted Air- Pump receiver a. 2888 2889 2890 2891 2892 2893 220 10 6 1 10 A thin film of ice may be formed by this apparatus in the warmest weather. Leslie's apparatus is the basis of many forms of Ice Producing Machines of the present day. Leslie's Experiment was first made in June, 1810, and is the converse of the experiment, No. 2859, page 471, viz., the production of heat by rapid compression. Apparatus, consisting of three glass vessels, for illus- trating the mechanical properties of air . Glass Flask, mounted with Brass Stopcock, for illus- trating the influence of diminished pressure in facilitating ebullition (fig. 2861) . Philosophical Water Hammer, (fig. 2 890), for exhibiting the force f and solidity with which water falls in a Yacuum . Water Hammer, Y shaped, closed at one end, and having a brass mounting and stop-cock at the other for exhaustion by the Air Pump (fig. 2891) BaUoons of Gold Beaters' Skin, for filling with Hydrogen Gas from 12 6 12 6 15 046 7 6 12 6 036 Apparatus for demonstrating the pressure of the atmosphere to be about ]5 Ibs. upon the square inch [of surface, an improved form of the Magde- burgh Hemispheres. A brass box, one inch square, is fitted with a ground metal cover, and also a stopcock. When exhausted of air, the cover can be connected to a steelyard, which shows that a force equal to about 15 Ibs. is required to remove the cover of the box; mounted on a convenient stand (fig. 2893) 3 10 This apparatus is so constructed that the exhausted box can be screwed into the cross bar on top of the upright pillars, and by means of the pulley and cord and a weight, it can be demonstrated that the pressure on the lid of the box is similar in both positions. 45, CORNHILL, B.C., AND 122, REGENT STREET, \V., LONDON. 475 FIG. 2t>2. FIG. 2858. FIG. 2859. FIG. 2855. FIG. 2856. 2894 Bladder Frame and Lead Weights, for illustrating the Each. Each. s. d. s. d. elasticity of the air , 12 to 16 2895 Lungs Glass, for illustrating elasticity of air (fig. 2895) 2896 Gun-Lock Experiment, for striking flint and steel in vacua ......... 2897 Breaking Squares, of thin glass, to illustrate the pres- sure and also the expansive power of air . 2898 Wire Cage, for use with above, to protect the Glass Receiver A FIG. 2871. FIG. 2846. FIG. 2890. FIG. 2891. FIG. 2864. 086 1 10 026 056 FIG. 2895. 2899 Receivers for Air Pumps, well annealed Glass, with accurately ground, welted edges 2900 Bell Shaped Close Receivers, (fig. 2900 and 2900), diameter; across the welt: 4-in. 5-in 6-in. 8-in. 10-in. 12-in. 5s. 8s. .10s. 6d. 16s. 6d. 25s. 34s. 2901 Bell Shaped Open Receivers (fig. 2901), including ground plate glass cover : Diameter 4-in. 5-in. 6-in. 8-in. 10-in. 6s. 9s. 12s. 18s. 6d. 28s. 2902 Cylindrical Shaped Receivers, Close : Diameter 4-in. 4s. 6d. 13-in. 42s. 5-in. 6-in. 8-in. 10-in. 12-in. 7s. 8s. 6d. Us. 6d. 18s. 22s. 476 NEGBETTI AND ZAMBRA, EOLBOKN VIADUCT, E.G., FIG. 2900* 6-in. 12s. 6d. 8-in. 15s. 6d. FIG. 2901. FIG. 2900. 2903 Cylindrical Shaped Receivers, Open (fig. 2846) Diameter 4-in. 5-in. 6s. 6d. 7s. 6d. 2904 Tall Cylindrical Glass Receiver, Open (fig. 2878), for Guinea and Feather experiment . . . . 16 1 10 2905 Tall Glass for Fountain Experiment . . 12s. 6d. 1 1 150 2906 Air Gun, complete with condensing syringe, bullet mould, &c., in case with lock and key. Made to order. Price 21 2907 Mariotte's Apparatus, arranged to show that under the pressure of two atmospheres air is compressed into half its ordinary volume (fig. 2907) 1 10 2908 Mariotte's Apparatus, to exhibit that air expands to twice its ordinary volume under diminished pressure, equal to half an atmosphere 150 "Boyle's Law, The law of the compressibility of gases, was discovered by Boyle and Mariotte independently (about the year 1670). In consequence, it is in England commonly called Boyle's law, and on the Continent, Mariotte's Law. This Law is as follows : The temperature remaining the same, the volume of a given quantity of gas is inversely as the pressure which it bears. Nos. 2907 and 2908 are constructed for verifying this law. "In experiments with Mariotte's Tube, as the quantity of air remains the same, its density must obviously increase as its volume diminishes, and vice versa. The law may thus be enunciated : For the same temperature the density of a gas is proportional to its pressure." Hence as Water is 770 times as heavy as Air, under a pressure of 770 atmospheres air would be as dense as water. FIG. 2907. 2909 Sets of Pneumatic Apparatus, packed in case, consisting of single or double barrel Air Pump, open and close receivers, fountain apparatus, pair of hemispheres, sliding wire and collar, syringe and lead weight, bladder, frame, and weight, filter cup and glass for mercury, hand glass and fruit stand . . 5 5s.; 10 10s. ; 21. 45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 477 FlG. 2918*. FlG. 2918. FlG. 2914. FlG. 2910. FIG. 2913. FlG. 2912. HYDROSTATICS AND HYDRAULICS. 2910 Hydrostatic Paradox. An apparatus to prove that a Each. Each. small column of water will support a much larger s. d. a. d. quantity, and also that fluids will rise and maintain the same level, whatever shape or size the channels through which they flow ; in Glass (fig. 2910) from 026 056 2911 Hydrostatic Paradox, large size (fig. 2911), in japanned metal . .440 550 FIG. 2915. FlG. 2921. FlG. 2939. FIG. 2919. 2912 Hydrometer, for testing the Specific Gravity of light or heavy fluids, various (see pages 176 to 195) (fig. 2612). 2913 Gravimeter, for ascertaining the Specific Gravity of Solids, Stone Minerals , Precious Stones, &c. (see also No, 533, page 190) (fig. 2913). 478 NEGRETTI AND ZAMBEA, HOLBOEN VIADUCT, B.C. FIG. 2935. FIG. 2936. FIG. 2938. 11 6 220 440 10 6 3 3 18 2 6 A be a. d. s. d. 2914 Boyle's Tube, for exhibiting the comparative Specific Gravity of two different liquids, or the law that the heights of columns of fluid which counterbalance each other under the ordinary atmospheric pressure are inversely proportional to the density of such fluids (fig. 2914) .... 2915 Hydrostatic Bellows, to illustrate that fluids press equally in all directions, and the pressure in proportion to the height of the vertical column of fluid (fig. 2915) 2916 Artificial Fountains, by Condensed Air, consisting of a Copper vessel, with condensing pump, and a variety of jets for fragrant waters, &c., packed in case from 2917 Extra jets for ditto, of various shapes .... 2918 Pewter, Copper and Glass Syphons, of various forms (see Chemical section) (figs. 2918, 2918*) . from 2919 Tantalus Cup, an illustration of the use of the Syphon (fig. 2919). small syphon is concealed within the figure, so that water may poured into the glass vessel until it nearly rises to the mouth, when the syphon commences to act and rapidly draws off the water 12 6 2920 Apparatus to explain the theory of Intermitting Springs 3 10 2921 Ditto ditto simple form in glass (fig.2921 ) 076 2922 The B/ope Pump of Vera, or Hydraulic Belt. This machine, the use of which has been revived within a few years, is one of the most simple and at the same time efficient of Water Elevators, and yet the most inexplicable in its action. In its ancient form it consisted of a number of hair ropes (for which a band of flannel or felt is now substituted), passing over two rollers, one at the bottom of the well and the other at the top. By means of the upper roller the band is set in very rapid motion, when the water in the well adheres to its surface in a layer, which is thicker the more rapidly the band moves, and becomes nearly half-an-inch thick when the velocity is 1,000 ft. per minute. The water follows the band to any height and is thrown off by centrifugal force in turning over the upperjroller. 2923 Model of Chain pump 2924 Persian or Bucket Wheel 2925 Model of Eccentric Pump 2926 Model of Water Pressure Engine Models of Nos. 2922 to 2924, constructed to order. 45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 479 FIG. 2927. FIG. 9240. FIG. 2934. 3 10 5 10 2 10 2927 Model of Centrifugal Pump, for raising water by means of Centrifugal force, combined with atmospheric pressure (fig. 2927) . 5 10 Appold's Pump has been most advantageously applied to drainage purposes, very large quantities of water being rapidly and easily raised by it to small heights. It has been found particularly useful for draining marshy or fen land. This pump was worked on a grand scale at the Exhibition of 1851. Model of Barker's Mill: by this machine a rotatory motion is obtained by the centrifugal force of the water employed ........ Model of Archimedes' Screw, or Water Snail, a machine for raising water to small heights requiring little power, with glass tube or worm . Model of Hero's Fountain, invented 120 years B.C. Mongolfier's Water Earn : this machine, by the momen- tum acquired from the flow of water through a pipe, forces a small column to a considerable height* . Apparatus for illustrating the laws by which fluids Spout through various adjutages . . . . 3 Apparatus for showing that more water flows from a short tube than through a simple aperture of equal diameter Apparatus for exhibiting and illustrating the Centre of Buoyancy and Meta-Centre as applied in ship-building (fig. 2934) A Series of Six Glass Tubes, of varying internal diameter, for showing capillary attraction (fig. 2935) Two Plates of Glass, arranged for showing the hyper- bolic curve produced by capillary attraction (fig. 2936) 2937 Hollow Glass Balloons and Figures, or Cartesian Divers, for ascending and descending in a tall air-tight vessel of water, as the pressure on the surface is increased or diminished . . Ditto In Glass vessel complete (fig. 2938) . Glass Model of Diving Bell, with Syringe (fig. 2939) . 2928 2929 2930 2931 2932 2933 2934 2935 2936 880 30 550 110 136 1 10 10 6 15 6 2938 2939 2 12 3 10 * Now need on alarge scale for raiting Water to small heights where water is abundant. 480 NEGEETTI AND ZAMBEA, HOLBORN VIADUCT, B.C., 2940 Working Model of Bramah's Hydrostatic Press, s. a. raising 400 Ibs., brightly finished^ with keys and breaking irons complete (fig. 2940) . . . . 12 12 2941 Model of Undershot Wheel 2942 Model of Overshot Wheel 2943 Model of Breast Wheel 2944 Model Canal Lock and Sluice Gates . . from 2945 Current Meters, for showing the Rate or Flow of Tide in a Stream or River, and the amount of gallons per hour delivered (see also page 299, No. 1190) Nos. 2941 to 2944, made to order. 18 18 4 4 4 4 4 4 10 10 660 770 HYDROMETERS, SACCHAROMETERS, GRAVIMETERS, ETC., FOR DETERMINING THE SPECIFIC GRAVITY OF FLUIDS AND SOLIDS (SEE PAGES 176 TO 195) HYDRAULIC PRESSURE GAUGES (SEE PAGES 205 TO 209). WATER PRESSURE. Pounds per Square IncTi, at Different Heights. Height in feet. 5 Pressure in Ibs. per square inch . 2-17 Height in feet. 100 Pressure in Ibs. per square inch 43-3 10 4-3 120 51-9 20 8'6 140 60-6 30 12-9 150 65-0 40 17-3 160 69-3 50 21-6 180 779 60 25-9 200 86-6 70 30-0 250 108-3 80 34-6 300 129-9 90 38'9 Each 33 feet vertical height of water equals one atmosphere, or 15 Ibs. nearly. In Sea Water sp. gr. 1'027, the pressure in descending increases at the rate of 280 Ibs. upon the square inch for every 100 fathoms, or exactly 1 ton for every 800 fathoms. ATMOSPHERIC PRESSURE. Pascal's celebrated experiment was made at Rouen in 1646. He took a tube of nearly 50 feet long, closed at one end, and having filled it with water, placed it vertical with the open end in a vessel of water, 'and found that a column of water was supported in the tube of 34 feet long, and is 13'6 times higher than the mercury. Mercury being 13 f 9 times heavier than water, the weight of this column of water was exactly equal to that of the mercury in Toricelli's experiment, and consequently it was the same force, viz., the pressure of the atmosphere, which supported the two fluids. Assuming that the tube in Pascal's experiment is equal to a square inch in sectional area, and that the height of the mercurial column is 30 inches, this column will contain 30 cubic inches ; and as a cubic inch of mercury weighs 3433-5 grains, or 0'49 of a pound, the pressure of this column on a square inch of surface will be found to be 14*7 pounds. The pressure of the atmosphere is in round numbers taken at 15 Ibs. on the square inch. The pressure upon a square foot of surface containing 144 square inches is equivalent to 2,160 Ibs., or very nearly 1 ton. The surface of a man's body of average size is equal to about 16 square feet ; the pressure therefore exerted upon this area, 37,560 Ibs., or upwards of 16 tons. Air is 813*67 times lighter than water. MODELS AND APPARATUS FOB ILLUSTRATING THE PHENOMENA OF HEAT, THE STEAM ENGINE, Ac, FIG. 2995. FIG. 2946. FIG. 2996. FIG. 3003. FIG. 2997. HEAT. " IN the study of nature two elements come into play, which belong respectively to the world of sense and to the world of thought. "We observe a fact, and seek to refer it to its laws ; we apprehend the law, and seek to make it good in fact. The one is Theory, and the other is Experiment, which when applied to the ordinary purposes of life becomes Practical Science. Nothing could illustrate more forcibly the wholesome inter-action of these two elements than the history of our present subject, viz., Heat. If the Steam Engine had not been invented, we should assuredly stand below the theoretic level which we now occupy. The achievements of heat through the steam engine have forced, with augmented emphasis, the question upon thinking minds : ' What is this agent, by means of which we can supersede the force of winds and rivers, of horses and men ? ' " Heat can produce mechanical force, and mechanical force can produce heat ; some common quality must therefore unite this agent and the ordinary forms of mechanical power. The relationship established, the generalising intellect could pass at once to the other energies of the universe, and it now perceives the principle which unites them all. Thus the triumphs of practical skill have promoted the development of philosophy. Thus by the inter-action of thought and fact, of truth conceived and truth executed, we have made our science wha,t it is the noblest growth of modern times, though as yet but partially appealed to as a source of individual and national might." Heat a Mode of Motion, by JOHN TYNDALL, LL.D., F.R.S., Prof, of Nat, Philosophy in the Royal Institution of Great Britain. 2 I 482 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, B.C., 2946 Marcet's Apparatus, for showing the Temperature and Elastic force of High Pressure Steam, and the most important facts connected with Latent Caloric (fig. 2946) price 440 Marcet's Apparatus consists of a strong iron boiler, mounted on a tripod stand, with a stout barometer tube of about 33 inches in length, and open at both ends, passing through a stuffing box on the top of the boiler to within a short distance of the bottom : attached to the tube is a scale divided into inches and tenths; on one side of this tube is mounted a very accurate thermometer, and on the opposite side is placed a stop -cock, to which can be attached tubes for conducting the steam to any vessel or apparatus for experiment. When in use, about 8 ounces of mercury are poured into the boiler, which is then half filled with water. By the application of heat the water is boiled with the stop -cock open, from which will issue steam, and the temperature indicated by the thermometer will be 212 degrees of Fahrenheit, when the barometer stands at 30 inches. Upon closing this stop-cock the pressure will be increased, and will gradually force the mercury from the bottom of the boiler up the tube, until it marks about thirty inches on the scale, the pressure being equal to one additional atmosphere (15 Ibs.), and the temperature marked by the thermometer will be 250 Fahrenheit, showing the relation between pressure and temperature in the formation of steam.* 2947 Dr. Ure's Steam Apparatus, for demonstrating the same facts as Marcet's price 440 2948 Benevides' Steam Apparatus (fig. *2948), shows a modified and larger form of Marcet's Apparatus, contrived by Professor Benevides, of Lisbon, for exhibiting in a lecture room or to a class the various properties of Steam. It consists of a strong boiler, B, and on the top of it are three stuffing boxes, b, c, and d, with fittings for a thermometer, a barometer tube, and a mercurial syphon pressure-gauge, all mounted with suitable scales. A model of Giffard's injector, G, is also adapted to the boiler. At A is a stop-cock, for connecting any piece of apparatus to be experimented with. Among many important facts to be demonstrated by this apparatus is the amount of heat] rendered latent when any given quantity of water is converted into steam and other phenomena of latent heat the laws of ebullition, the influence of pressure over the boiling point of water, the connection between temperature and the elastic force of steam, the production of motion by the elastic force of steam, &c. The action of Giffard's injector is also very prettily illustrated, a small jet of water being easily projected 12 ft. with a good pressure of steam. Fig. 2948, Price 5 10 2948* " It is proved by experiment that the quantity of heat necessary to raise one pound of water one degree "of Fahrenheit in temperature is equal to that generated by a pound weight falling from a height of 772 feet against the earth. Conversely, the amount of heat necessary to raise a pound of water one degree of temperature would, if all applied mechanically, be competent to raise a pound weight 772 feet high, or it would raise 772 pounds one foot high. The term 'foot-pound ' has been introduced to express in a convenient way the lifting of one pound to the height of a foot. Thus the quantity of heat necessary to raise, the temperature of a pound of water one degree Fahrenheit being taken as a standard, 772 foot-pounds constitute what is called the mechanical equivalent of heat. If the degrees be Centigrade, 1,390 foot-pounds constitute the equivalent." Tyndall. * See Dr. A. S. Taylor's Thermometric Table. 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 483 FIG. 2918. Each. s. d. 2949 Glass Flask, mounted with brass stop-cock, for experi- ments with heat under diminished pressure (fig. 2446, page 470) 2950 Cubical Tin Vessel, (Leslie's Cube), with stop-cock, to illustrate the expansion of water into steam by heat and contraction (or condensing) by cooling 2951 Air Thermometer, for ascertaining very small differ- ences of temperature by the expansion of air. Invented by an Italian Physician, Santorio, in the Seventeenth Century (fig. 2251) 15 2952 Leslie's Differential Thermometer (fig. 2952) . . 1 10 2953 Wollaston's Boiling Point Thermometers (see pages 92 to 94.) 2954 Tyndall's Apparatus, to demonstrate the production of Heat by friction. See also No. 2144, page 492 2955 Thermometers (fig. 2955), various, and for High Temperatures, Iron, Brass, or Copper mountings. Each. s. d. 10 6 10 6 110 220 660 (See page 1G7.) 484 NEGRETTI AND ZAMBRA, HOLBOEN VIADUCT, E.G., C C A FlG. 2956. PYEOMETEES. 2956 Pyrometer, Professor Darnell's, is perhaps the most practically useful; fig. 2956 shows its general arrangement. The indications are obtained from the difference in the expansion by heat of an iron or platinum bar and a tube of well-baked black-lead ware, in which the bar is contained. The metal bar, A, is shorter than the tube, and a short plug of earthenware, B, is placed in the mouth of the tube resting upon the iron bar, and so secured by a strap of platinum and a little wedge that it slides with difficulty in the tube. By the expansion of the metal bar the earthenware plug is pushed outwards, and remains in its new position after the contraction of the metal bar on cooling. The expansion of the metal bar thus obtained is measured off by the instrument and index, C, which traverses over a divided circular scale S before the experiment, and after the earthenware plug has been moved outwards by the expansion of the metal bar B. The degrees marked on the scale are in each instrument compared experimentally with those of the mercurial scale, and the ratio marked on the instrument, so that its degrees are convertible into those of Fahrenheit. (Philosophical Transactions, 1830 31,) In use the black- lead cylinder, P, with its metal expansion bar, A, enclosed, is placed into the metal or furnace to be tested, the length of the metal bar being noted on the divided arc, S, previous to the operation, and after its exposure to the heat to be tested. Price 550 2957 Ferguson's Pyrometer, a lecture table instrument, for demonstrating the expansion of metals by heat, the relative amount of expansion of different metals being shown upon the divided Quadrant seen in fig. 2958 Price, simple form 440 45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 485 FIG. 2958. 2958 Ferguson's Pyrometer, in its most complete form, fitted up with an Oil or Water Batli for uniformly heating the metal rods under experiment, the Temperature of the Bath being shown by a delicate Thermometer fitted to it ... Price, complete with Bath and Thermometer (fig. 2958) 5 10 2959 Wedgewood's Pyrometer: with this instrument the degree of heat is estimated by the permanent contraction of a prepared Cylinder of Pipe- Clay or Porcelain; but its indications (except for one or two special purposes) are found to be fallacious and of little practical value. Supplied to order. For Gauntletfs, Bystroin's, and Siemen's Pyrometers, see pages 203 and 204. 2960 Fire Syringe, for exhibiting the evolution of Heat by the rapid Compression of Air. This is the converse of Leslie's experiment (page 475), in which Cold is produced by the rapid rarefaction of air . . .056 086 29t>l Metal Bar and Gauge, for showing, in a simple and conclusive manner, the expansion of metals by heat (fig. 2961) 076 The Metal Bar when at the ordinary temperature of the air will fit tightly into the gauge ; but if it be warmed, the metal will be expanded, and prevent the bar from fitting into the gauge until it is again cooled. 2962 Gravesand's Metal Ball and Ring, for exhibiting the same fact , 10 6 2963 Compound Metal Bar, to exhibit in a striking manner the Expansion and Contraction of metals by heating and cooling. This bar is made of two slips of metal of differing expansibility by heat (Iron and Brass). When Cold this bar is perfectly straight, but if heated by the flame of a Spirit Lamp it becomes curved . Price, for Bar only 60 086 2964 Compound Metal Bar, with Stand, large size, for Lecture Table 15 2965 Compound Metallic Bar Thermometer, (Brequet's), in the form of a Watch 440 See also the Metallic Clinical Thermometers, Medical Section, for an adaptation of Breguet's Instrument. 486 NEGRETTI AND ZAMBRA, HOLBOKN VIADUCT, E.G., FIG. 2970. FIG. 2995. FIG. 2961. FIG. 2952. FIG. 2951. 2966 Spiral Metallic Thermometer, of larger size, see page 460, Used for Alarm purposes, &c. 2967 Hope's Apparatus for determining the Maximum density of Water, consists of a cylindrical glass jar, with an external Copper vessel for holding a mixture of Ice and Salt, and two Thermometers with projecting bulbs, with attached scales, as shewn in the engraving, fig. 2967. See Ganot- Price 14 2968 Apparatus to show that liquids expand by increase of temperature and bceome of a lighter specific gravity, consisting of a large glass tube, closed at one end, for holding water, on which floats a small hydrometer adjusted to a temperature of 60. Upon warming the water over a spirit lamp the hydrometer will sink ; but it will rise to the surface when the water cools to 60 10 6 2969 Apparatus for showing the varying Expansion of Liquids, and the construct- tion of Thermometers. It consists of five large Thermometer tubes, partly filled with Mercury, Alcohol, Ether, Oil, and Water ; arranged on a stand with tin trough. Graduated scales are fitted to each tube, by which the relative expansion of the liquids in a given time can be observed, when the trough is filled with hot water . Price for Lecture Table size 330 2970 Cryophorous, or Frost Bearer, (fig. 2970, Dr. Wollaston's), is a glass tube with large bulbs at each extremity, as fig. 1948. These bulbs and tube are nearly exhausted of air, and a small portion of water, about half filling one bulb, left in it. If the empty bulb be surrounded with a mixture of pounded ice and snow the rapid evaporation taking place from the surface of the water will cause it quickly to freeze . .046 066 2971 Apparatus for showing the Conducting power of various metals 10 6 2972 Cylinder of Wood and Brass, to show Conduction by a strip of paper 036 2973 Parabolic Reflectors, of highly polished zinc, for Experiments on Radiant Heat . . . per pair 440 550 2974 Stands for ditto with simple adjustment . per pair 140 45, CORNHILL, E.G., AND 122, EEGENT STREET, W., LONDON. 487 FlG. 2975. FIG. 2991. Each. Each. 2975 Stands for Reflectors, best make, with jointed adjust- ments (fig. 2975) per pair 2 12 6 2976 Ditto for Iron Ball, &c. 086 2977 Parabolic Conjugate Reflectors or Mirrors, 18 inches diameter, Stout Silvered Copper, mounted on adjustable Stands, with Iron Ball and Stand 10 10 2978 Leslie's Radiator, or Cube, small size .... 056 2979 Ditto ditto larger, with adjusting Stand . . 15 110 2980 Leslie's Radiator is a square tin vessel, each of the four side surfaces being different. One is left bright, one roughened, one dull white, and the other black. The vessel being filled with boiling Water the various surfaces will be found by the use of Leslie's Differential Thermometer (No. 2952) to radiate or give off varying amounts of Caloric. 2981 A Set of Three Leslie's Cubes, each having inserted a delicate Thermometer for noting the rate of cooling of the liquids in the vessels dependent upon their exterior surfaces. Price, for 3 best mounted Cubes 2 10 2982 Leslie's Pyroscope, for ascertaining the comparative radiation of various bodies 1 10 6 2983 Ditto ditto an improved arrangement (fig. 2983) as described by G-anot 330 2984 Radiation, Reflection, or Absorption of Heat Apparatus ; consisting of two flat metal discs, having one side blackened and the other bright, with small cups or shelf for holding pieces of Phosphorus. These discs being placed at equal distances from a heated Iron Ball, the Phosphorus will be inflamed on the black surface, whilst that on the bright one will remain imchanged . . . 18 (> 2985 Boutigny's Experiment for exhibiting the spheroidal condition of water when in contact with a strongly heated surface, and also the non-conducting power of vapour . ... . ." .330 2986 Silver Bottle !and Stopper, for exhibiting the sudden evolution of steam in Boutigny s experiment 220 2987 Apparatus to show the Imperfect Conducting Power of Water, consisting of a sensitive Air Thermometer, so arranged that Ether can be ignited upon the surface of water surrounding the air bulb, without producing any movement in the thermometer . .110 2988 U Shaped Glass Tubes, for illustrating Convection . . .050 2989 Faraday's Convection Apparatus, best form, on a stand, for illustrat- ing the mode of heating buildings, &c., by hot water . . . 18 2990 Tyndall's Geyser Apparatus, of large size, with Zinc Trough and Copper Corners 700 488 NEGRETTI AND ZAMBEA, HOLBOEN VIADUCT, B.C. FIG. 2967. FIG. 2983. 2991 FIG. 2993. s. d. Apparatus to exhibit the principle of Ventilation, showing an ascending current of heated air and a descending current of cool air to supply its place (2991) 12 6 Fine Wire Gauze, for experiments on Flame, demonstrating its inability to pass through a medium formed of Metal Threads, owing to their cooling or conducting power, for explaining the theory and action of Davy's Safety Lamp, 8 inches square 020 Improved Safety Lamps, Universal Clanny, with Swivel and elastic ring, to allow for expansion of the Glass (fig. 2993*) . . 17s. 6d. 1 5 Glass Apparatus, for exhibiting the evolution of latent heat by a mixture of two cold fluids. The glass vessel is partly filled with "Water, and upon its surface is floated a small light capsule, into which a little piece of dry Phosphorus is placed; now if strong Sulphuric Acid be carefully poured into the water, sufficient heat will be produced to ignite the Phosphorus 086 Bunsen's Ice Calorimeter, for experiments on Specific Heat, (fig. 2995, see Ganot) 6 15 Various other experiments illustrating the Phenomena of Heat, see Chemical Section. 2992 2993 2994 2995 FIG. 3005 e FIG. 3009. * See also page 404. 45, COENHILL, E.G., AND 122, REGENT STEEET, W., LONDON, 489 FIG. 3009*. MODEL STEAM ENGINES. 2996 Dr. Wollaston's Apparatus, showing the production of motion by the generation and condensation of steam (fig. 2996) . 10 6 15 6 2997 Glass Models of Hero's Rotatory Steam Engine (Eolipyle), mounted on stand, with Spirit Lamp (fig. 2997) 056 0106 2998 Toy Models of Branca's Engine 050 076 2999 Working Models of Hero's, De Cans', Branca's, Savory's, Papin's, Newcomen's, Hornblower's, and Cartwright's Steam Engines . made to order. 3000 Working Models of Sawing, Rolling, or Grinding Mills, Cranes, Pile Driving Engines, Steam Hammers, Pumps, &c., &c. . . made to order. 3001 Working Model of Watt's Low Pressure or Condensing Engine 21 3002 Ditto, Watt's High Pressure ditto . . . 5 5 10 10 15 15 3003 Working Model of High Pressure Oscillating Engine, with boiler and lamp attached (fig. 3003) 110150 1100 3004 Ditto ditto larger and better finished, bright metal 2 10 3005 Horizontal Steam Engines, as fig. 3005, with brass boiler, Oscillating Cylinder, steam cock, safety valve, fly wheel, on japanned stand with lamp 1 10 3006 Ditto ditto larger, and of higher finish . .220 2 10 3007 Horizontal Steam Engine, with fixed cylinder and slide valve, eccentric motion, boiler, &c., &c., on mahogany stand . .550 660 FIG. 3010. 3008 Locomotive Engine, Working Model, in cheap form, of japanned metal 220 2 10 490 NEGRETTI AND ZAMBRA, HOLBOKtf VIADUCT, B.C., 3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019 FIG. 3011. Locomotive Engines, Working Models, of superior finish and larger size, of Bright Metal (fig. 2109 and 2109*). 330 440 550 6 6 8 8 10 10 Ditto ditto Six Wheels, with Tender, as fig. 3010 . . 14 14 Working Model Locomotive Engine, of bright brass, highly finished, with japanned tender and carriage, and Circular Railway (fig. 3011). 8 10 10 10 12 12 FIG. 3018. d. s. d. Working Model of Steam Fire Engine, will throw a jet of water a considerable distance .... 15 15 Working Model of a Marine Beam Engine, with paddle-wheels, &c Working Model of Penn's Vibrating Engine. These engines, being simple and compact, are extensively employed in the Thames steam -boats . . from Model Steam-Boats, fitted with working engines and Paddle Wheels, or Screw Propeller . . 10 10 15 15 25 Model of Perkins' Steam Gun, for projecting bullets, with a strong boiler, generating steam at a pressure of 200 k lbs. per square inch ...... Painted Wooden Sectional Models of High and Low Pressure Engines and Locomotives, of various con- structions, showing the exterior of the engine, and the working of the parts, such as the cylinder, condenser, piston, valves, &c. . . . from 880 12 12 Small Sectional Working Model of Condensing Engine, made of cardboard and metal (fig. 3018) . Sectional Diagrams and Plans of Steam Engine, &c., suited for Lectures, various according to size, to order. 25 30 20 14 2 10 330 45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 491 FIG. 3021. MECHANICS AND DYNAMICS The Models, &c., detailed in this section will be found valuable aids to the teacher and student in studying the laws of motion and the science of Mechanics. Each. 3020 Model Apparatus for exhibiting and illustrating the properties of the Mechanical powers, viz., levers, simple and compound, pulleys of different kinds, wheel and axle, inclined plane, screw, wedge, capstan, &c., in mahogany and boxwood ; in case, with weights complete ......... 3021 Mechanical Powers, more highly finished, and com- plete with Brass pulleys, &c. (fig. 3021) . 3022 Sets of Levers, comprising the three orders, and the bent form ......... 3023 Ditto ditto in Brass 3024 Systems of Pulleys, Simple and Compound . 3025 Inclined Plane, with Carriage and Weights 3026 Models, to show the formation of the Screw and Nut, to illustrate the action of screws of different degrees of inclination, the endless screw and compound screws . 3027 Adhesion Plates, of Glass, with handles 3028 Inertia Apparatus, with Brass ball, mounted on a stand 3029 Apparatus for showing the impenetrability of matter . 3030 Apparatus for determining the Centre of Gravity of variously shaped bodies s. a. Each. s. 5 10 10 10 21 220 15 110 10 5 2 10 5 5 15 1 10 5 1 10 492 NEGBETTI AND ZAMBRA, HOLBOEN VIADUCT, B.C., FIG. B. FIG. A. FIG. 3044. 3031 FIG. c. s. d. Apparatus illustrating that the stability of a body depends upon the centre of gravity, see also No. 2934 3032 Double Cone and Inclined Plane, to show the descent of the centre of gravity, although the cone apparently moves upwards . . . . . . . . 10 6 s. d. 12 6 16 FIG. 3034. 3033 Apparatus for illustrating the Parallelogram of Forces, with weights, &c., of the best finish, complete . . . . .660 3034 Attwood's Machine for demonstrating the laws of falling bodies, with pendulum beating seconds, weights, &c., complete on stand, with best Clock and highly finished (fig. 3034) 25 3035 Ditto ditto simple form . . . 12 12 3036 Apparatus to show that a body takes the same time to descend the diameter or chord of a circle, whatever the length of that chord maybe 220440 3037 Apparatus to illustrate that the time required for the descent of bodies down an inclined plane is proportionate to its length 220550 3038 Apparatus to illustrate the Composition of Force % 3 3039 Apparatus to demonstrate that the time required for a falling body to reach the ground is the same, whatever be the force of projection . . . .330550 45, CORNHILL, E.G., AND 122, EEGENT STREET, W., LONDON. 493 FIG. 2694. FIG. 3049*. Each, s. d. 220 3040 Apparatus to illustrate the curve of quickest descent 3041 Ditto to show the Parabolic Curve described by a projectile 3042 Ditto to illustrate the laws of Impact collision or per- cussion, with divided arc and ivory balls (fig. 3042) 3043 Ditto to illustrate the Equilibrium of Forces, complete 3044 Whirling Table or Centrifugal Machine and Apparatus complete, for illustrating the laws of Central Forces (fig. 3044, A, B, c.) 3045 The Whirling Table only, without apparatus. This can be used for Tyndall's experiment, No. 2954, page 483, for producing Heat by Mechanical Action or friction 3046 Model to illustrate the construction and properties of an Arch 3047 Model to show the properties of crown, spur, and bevel wheels, wheel and pinion, and rack and pinion '. 3048 Model to demonstrate the properties of Steelyard and Balance 11 3049 Model of Capstan or Windlass 1 10 3049 Model, to demonstrate the principle of the Wedge- Metal Wedge and rollers in Mahogany Frame (fig. 3049*) 3050 Glass Models, for teaching Geometry and Crystallography 3051 Small Sets of Geometrical Solids and Planes 3052 Larger Sets of ditto, with sections of the Cylinder, Cone, and Sphere 3053 Professor Maxwell's Dynamical Top, for illustrating the phenomena of rotation, complete in Mahogany Box 3054 The Gyroscope, for description and price see page 495. Each. s. d. 330 220 330 660 21 660 220 660 2 2 .0 220 3 10 220 10 6 1 10 "0 6 10 494 NEGRETTI AND ZAMBRA, HQLBOEN VIADUCT, B.C , EXPERIMENTS TO ILLUSTRATE ACOUSTICS. Each. Each. s. d. s. d. 3056 Apparatus for producing Musical Sounds with a jet of Hydrogen Gas burning in a glass tube, Musical Flames 1 10 3057 Apparatus for exhibiting a Rotating Singing Flame from 4 16 6 3058 Trevyllian's Experiment, or Rocking Bar, for producing sound by the vibrations of a Heated Copper Bar upon a Cold Block of Lead ... ... 18 3059 Bell Experiment, for proving sound depends upon the presence of Air (see also page 473) . . . . 15 1 10 3060 Improved Arrangement of the Experiment, with Electro Magnetic Apparatus for setting the Bell in motion, having a glass receiver, fitted with two stopcocks, for experimenting upon the different gases 4 10 3061 Polarization of Sound, Apparatus for demonstrating, consisting of a Tuning Fork and Glass Flask . 10 6 3062 Monochord, of simple construction, with adjusting weights, for altering the tension of the vibrating string, for showing the relation and sub-division of musical sounds 6 10 3063 Brook's Apparatus, to show the relation between the tension of a chord and the time of vibration . . 2 10 3064 Apparatus for exhibiting the vibration of elastic mem- branes by sand upon their surfaces (or Chladni's Acoustic Figures) ....... 1 12 3065 Steel Spirals, for producing various musical sounds, mounted on a sounding board, with a hammer . 300 3066 Syrene, for ascertaining the number of impulses, in a given time, required to produce any particular note. This is done by a clockwork movement, arranged to record the movement of a disc of metal, perforated with a series of holes, through which a current of air is forced . 550 3067 Wheatstone's Kaleidophone, to exhibit the principle of the superposition of small vibrations .... 1 10 3068 Organ Bellows, with double riser, wind chest, and sound board, with a set of wood and metal tongued pipes, for producing musical sounds 10 10 3069 Vibration Telephone. Not Electrical. Speaks Loudly and Clearly. Simple ahd cheap. In this apparatus a well-known principle of acoustics is practically applied. It consists of a Sound Box at each end, fitted with a properly insulated and stretched Wire between them. For distances of 30 to 1000 feet it will act well. Vibration Telephone, with Electric Call arrangement. 2 Telephones, 6 Insulators, 200 feet of suitable Wire, 2 Bells, 2 Keys and 2 Batteries complete, with instructions for fixing up and use . . . 5 12 6 Telephones and Transmitters (except for Export} cannot be supplied. The various Acoustic instruments, &c., invented and used by Messrs. Savart, Wheatstone, Biot, Tyndall, Konig, Helmholtz, Lissajous, Leon, Scott, and others, in their researches connected with Sound, described in Ganot's Physics, constructed and supplied to order, by Negretti and Zambra. 45, CORNHILL, E.C., AND 122, REGENT STEEET, W., LONDON. 495 FIG. 3073. FIG. 3072. FIG. 3071. 3070 The Gyroscope, a modification of Bohnenberger's machine, introduced by M. Foucault, is an instrument arranged to illustrate the following principles : That inertia is a property of matter in motion, as well as of matter at rest. That orbital and axial motion are intimately related, and that the speed of one may affect or regulate the other. That the state of unstable equilibrium in which many bodies remain is to be explained by the fact of their rotation. That bodies in motion endeavour to maintain their original plane of rotation. That the power of resisting or overcoming the force of gravity possessed by shots fired from Armstrong's gun is due to the gyratory motion given to them by the peculiar formation of the gun. It will also illustrate the precession of the Equinox. Each. 3071 Gyroscope, the simple form, with a stand (fig 3071) 1 10 6 3072 Ditto, of the best and most complete form (as fig. 3072), in mahogany cabinet .... 3 10 All other Instruments, Models, or Apparatus required to illustrate the Sciences for Educational or Lecturing purposes, constructed to order. FOUCAULT'S EXPERIMENTS WITH THE GYROSCOPE. 3073 The following illustrated description of the Gyroscope from a paper read by M. Foucault, before the British Association, " Nouvelles Experiences sur le Mouvement de la Terre au Moyen du Gyroscope," is from the Civil Engineer and Architects' Journal. 496 NEeKBETTI AMD ZAMBRA, HOLBOBN VIADUCT, B.C. " In the accompanying engraving [of the gyroscope (fig. 3073), A is a section of the periphery of the wheel, A A, which is constructed with a very heavy rim or periphery, and a light disc, B B, forming the arms by means of which the connection is made to the axis, C C, of the wheel. This axis is hung or connected to a ring, D D, by means of gymbal journals at a a ; this axis at each end being brought to a conical point, and dipping into the conical recess made in the end of the bolts b ; which bolts being screwed, pass through the brass hoop or ring, and are secured steadily by the jam-nut, d, in the position which permits of the free revolution of the axis, C C. This ring, D D, again is hung or connected to the brass ring, E E, by means of gymbal suspensions at e e. These gymbal suspensions are constructed in the same way (with bolts and jam-nuts) as those described suspending the axis C C, of the wheel A A. Again, this ring, E E, is suspended to the upper part, F F, of the stand, by another pair of gymbals similarly to the others. The box, F F, or upper part of the stand is provided with a prong, G, or long pivot, which dips into a socket on the top of the lower part of the stand, H. The apparatus so made is thus capable of the following motions : The wheel, A A, is capable of revolution on its axis, C C, within the ring, D D the ring, D D, including the wheel A A, is capable of revolution within the ring, E E. round the gymbal suspensions, e e; the ring, E E, is again capable of revolution within the box, F F, or upper part of the stand, round the gymbal suspensions that connect it to the frame or stand ; and finally the whole apparatus is susceptible of revolution horizontally on the pivot, G, which is inserted into the socket of the stand, H." The same journal then goes on to say : " With the apparatus so constructed a variety of beautiful experiments can be performed, of which the following are the more interesting. Kemove the ring, D D, carrying the wheel, A A, from the machine, set the wheel, A A, in rapid motion, which can be done by winding a piece of twine round the axis of the wheel, A A, and while holding the ring, D D, firmly in the hand, pull the twine violently, so as to uncoil it from the axis, C C ; suspend the ring, D D, by a piece of line attached to itself, or what is better, to the projecting head of the bolt which is outside of the ring at the gymbal journal ; and so long as the velocity of the wheel, A A, exceeds a certain amount, the ring, D D, will stand horizontally, though suspended on one side, or it will remain in any position forming an angle with the horizon in which it may be placed ; and while so suspended will slowly revolve round the suspending twine as a centre of motion. Thus the revolving motion of the mass of the wheel and axis resists the action of gravity on the mass, both of the matter which is in motion and on that which is at rest. " Another experiment is as follows : Place the ring, E E, perpendicular, the ring, D D, at right angles to it ; set the wheel, A A, in rapid motion in the same way as before, and assuming that while the machine is at rest it is in exact equilibrium, suspend while it is in motion a small weight on the projecting head of the bolt, which forms the axis of the wheel, and a horizontal revolution of the whole mass round the pivot centre of the stand will take place. Suspend now a heavier weight at the other end of the axis of the wheel, and the motion will be reversed ; that is, if with the light weight the revolution took place to the right or left hand, it will, after the addition of the heavier weight at the opposite end, revolve to the left or right hand, the direction being determined by the direction in which the wheel, A A, revolves. "A third very interesting experiment is the following: When the whole machine is at rest, if a stand be slowly turned round on the table, the whole mass will turn with it, the weight of the machine causing sufficient friction on the pivot to produce this effect ; but set the wheel in rapid motion as before, and the stand may be turned either way without disturbing the upper part of the machine, or altering the absolute direction of the axis of rotation. Thus, as with the pendulum experiment, can be shown the actual revolution of the earth, seeing that as the revolution of the earth takes place, it slowly revolves round under the gyroscope, the axis of which retains the same absolute direction in space. Instead of the ring, D D, being used to carry the axis of the wheel, A A, a semi-sphere is sometimes substituted, and in this form if the cup or semi-sphere be carried in the hand, the resistance which the moving mass offers to any change in the direction of the axis of rotation opposing any horizontal or perpendicular angular motion in the axis, gives the sensation as if the inanimate matter possessed life and_will of its own." 45, COBNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 497 PHOTOMETERS FOB TESTING ILLUMINATING POWER OF COAL GAS. & s. a. 3074 Glass Tube Pressure Gauge, with 6-inch Glass Syphon, with Stopcock, ivory scale, best finish 14 . 3075 Ditto ditto large size 12-inch Scale, best mounted . . 1 10 3076 Gas Inspector's Gauge, with best fittings complete, in Leather Pocket Case (see also page 197) 220 3077 Sensitive Gas Thermometers, 5-inch Ivory Scale, with projecting bulb for taking temperatures in gas mains, in Pocket Case . 10 6 3078 Bunsen's Photometer, for comparing and measuring the illuminating power of coal gas, and for testing the comparative value of various gas-burners . . . . . . . . .330 3079 Dr. Letheby's 60-inch Photometer, mahogany standards, gas pillar, with double cock, micrometer adjustment, slide for candle, wooden shades, &c 880 3080 Evans' Standard Photometer, 100-inch scale, in polished pine case lined with black velvet, with disc frame, central adjustment, slide ventilators, velvet canopy, &c., &c. 17 17 3081 Experimental Meter, 144 cubic inches capacity, combination index, minute clock and gas index working on one dial, 5 feet hourly rate of consumption, and time circle, small circles showing 5 feet actual consumption, and 10 minutes. The minute clock with lever escapement dead beat provided with bell, which is struck every minute . . . . . . . . . . . 12 12 3032 Sight-hole Beam, or brass cross-piece pillar, with brass chains and weights, scale for weighing two candles in candle holders whilst burning, grain weights 500 to i-grain, mounted on mahogany board 500 3083 King's Pressure Gauge, to show 100th part of an inch pressure, 3 3s. 4 4 3084 Specific Gravity Apparatus, for testing the gravity of Coal or other gases, consisting of a light glass flask of one Cubic Foot capacity, mounted with a Stop-cock and also a suitable Balance and grain weights, one grain being equivalent to 1'728 cubic inches of air .330 3085 Jet or Inferential Photometer (Lowe's), for testing and comparing the illuminating power of gas . . . . . . .440 3086 Testing Gas Holder, of 2 cubic feet capacity, with copper bell, double divided scale, balance wheel or friction rollers, cycloid and weights, gun metal taps, pressure gauge, &c., &c., complete for laboratory service , . . . 21 3087 Ditto ditto of larger size, with more finely divided scales and adjustments for testing meters 40 FOR GAS PRESSURE GAUGES, GAS TESTING THERMOMETERS, GRADUATED TUBES, SPECIFIC GRAVITY FLASKS, HYDROMETERS, &C., &C., SEE PAGES 153, 167, 176, 196, 206 AND 375. 2 K 498 NKGKETTI AND ZAMBRA, HOLBOEN VIADUCT, E.G., FIG. 3088. Fm. 3089. MEDICAL, SURGICAL AND PHARMACEUTICAL INSTRUMENTS AND APPLIANCES. Each. Each. s. d. s. d. 3088 Hutchinson's Spirometer, for measuring the Yital Capacity of the Lungs (fig. 3088) . 440 3089 Ditto ditto improved, with Dial Indicator, &c. (3089) . . .' 660 880 3090 Measuring and Weighing Machine, for use with the Spirometer 660 880 The object of this instrument is to measure that volume of breath expired from the lungs which is made by the deepest expiration immediately following the deepest inspiration. It has been determined by actual experiment upon 4,400 males, that this volume (or vital capacity) increases with the stature, quite irrespective of any other measurement upon the human frame. The law is For every inch of stature from 5 ft. to 6 ft., eight additional cubic inches of air, at 60 Fahrenheit, is (in the erect position) exhaled from the healthy lungs. In Consumption this volume is diminished 33 per cent, in the first stage, and 53 per cent, in the second stage of that complaint. As a man at 5 ft. 8 in. in health breathes 230 cubic inches, and a man in the first stage of Consumption breathes 154 cubic inches, so the healthy condition of the lungs differs from the pthisical lung. All diseases of the Chest dimmish the healthy volume of expired air. For particulars see Medico- Chirurgical Trans., vol. xxix., p. 137, and Cyclopaedia of Anatomy and Physiology, Art. THORAX. 45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON, 499 FIG. 3091. FIG. 3101. 3091 Portable Medical Spirometer, Patent (fig. 3091). This instrument from its very small size will be found a very useful addition to the consulting room of the physician, and to the physiological laboratory. The measurement of the vital capacity is obtained by measuring the velocity of the expired current during the time of expiration, and the instrument is arranged so as to reduce the velocity of the current to Cubic Measure. Each Spirometer is experimentally Tested by means of a vessel filled with air immersed in water, the cubic contents of this vessel being known ; the air is made to pass through the Spirometer at a pressure of six inches of water ; the Spirometer is then regulated to show the cubic contents of the vessel. By this means it is found the error of the instrument seldom amounts to more than 2 per cent. DIRECTIONS FOR USE. Each instrument is provided with a condenser, which should be placed in a tumbler of cold water ; the tube with the mouth-piece must be fixed to the orifice of the condenser, marked " in" and the instrument to that marked " out." The hands must then be set to zero by turning the milled head, at the same time pressing the spring forward. The patient is directed to take a deep breath, and then to expire steadily through the mouth-piece for as long as possible. The index hands register the number of Cubic Inches of Air expired. The use of the condenser is to prevent the moist air entering the instrument. After repeated use it is necessary to empty the accumulated water. This is done by disconnecting the instrument and inverting the condenser. Price 4 10 Table of the Vital Capacity of the Lungs, compared in Health and in Consumption, at 60 Fahrenheit, upon 5,000 Cases (Male). HEIGHT. HEALTH. CONSUMPTION. Ft. In. Ft. In. Mean. Minimum. First Stage. Second Stage Mixed. 5 to 5 1 174 146 117 82 99 5 1 5 2 182 153 122 86 102 5 2 5 3 190 160 127 89 108 5 3 5 4 198 166 133 93 113 5 4 5 5 206 173 138 97 117 5 5 5 6 214 180 143 100 122 5 6 5 7 222 187 149 104 127 5 7 5 8 230 193 154 108 131 5 8 5 9 238 200 159 112 136 5 9 5 10 246 207 165 116 140 5 10 5 11 254 213 170 119 145 5 11 6 262 220 176 123 149 2K2 500 NEGRETTI AND ZAMBEA, HOLBORN VIADUCT, E.G. Each. JS s. d. Each. B. d. 3092 Vacuum Tubes, or Laryngoscope, for illuminating the throat 110 3093 Jordan's Ear Illuminator 1 10 3094 Toynbee's set of Silver Specula, round or oval, with handle 110 3095 Speculum Auris various forms 15 1 10 3096 Warden's Auriscope 10 6 3097 Magnifying Lenses, for examining Skin Diseases, &c., for the Hand or Pocket, various forms and prices (see pages 223 to 224). 3097* Steinheil's Pocket Magnifier with Apian atic Lenses flat field with great power each 22s. 6d., 170 250 3098 Opthalmoscope, with Lenses complete, in pocket case, the improved arrangement 150 220 3099 Liebreich's Improved Opthalmoscope, with 2 Lamp Chimneys, in mahogany case 5 10 FIG. 3100. NEGRETTI AND ZAMBRA'S IMPROVED CLINICAL THERMOMETERS. 3100 The importance of ascertaining or watching carefully the variations of temperature in disease is daily becoming more apparent. Hitherto one of the main drawbacks to the general use of the thermometer by practitioners has been the fact that sufficiently portable instruments have not been obtainable. This difficulty is now entirely overcome in the Clinical Thermometer originally devised by Dr. Aitkin, now improved by Negretti and Zambra. Each instrument is tested by a Standard Thermometer, before being issued. Its portability is the great point. The Thermometers are 3, 4, 5, or 6 inches in length, and can be conveniently carried in the pocket: with Negretti and Zambra's improvement they are Self -Registering) and may be read off at leisure. The important gain is this, that the practitioner may always carry a Thermometer with an indestructible index about with him ; and thus find that he has a valuable aid, not only at ordinary, but at many chance times. Useful charts for daily recording the main points in physical Diagnosis have also been published. For prices and descriptive details, see pages 160 and 161. Kew Certificate to a Clinical Thermometer, extra, 2s. Negretti and Zambra's Clinical Thermometers are usually divided upon their stems with Fahrenheit or Centigrade scales ; if both scales are desired upon the same instrument there will be an extra charge of 2s. 45, CORNHILL, B.C., AND 122, BEGENT STREET, W., LONDON. 501 3101 Patent Metallic Thermometers (Immisch's Patent), for Clinical and ordinary uses (fig. 3101). The chief advantages that this instrument has over those in ordinary use are its convenient shape and size like a miniature watch, the readiness with which the temperature may be read off, and its comparative freedom from liability to in injury. It is sensitive and accurate. No shaking down being required, the instrument readily accommodates itself to altered temperatures. About 30 seconds elapses before the temperature last recorded is changed. This space of time is generally admitted to be sufficient to allow the Thermometer being taken to the light and its indications noted. These Thermometers are divided to both Fahrenheit and Centigrade Scales. Pi-ice in neat Leather Case, Silver, 1 Is.; Gold, 2 10 3102 Hygrometers, for Hospital Wards, &c., 14s., 21s., fig. 3102, see also page 73. 3103 Bath Thermometers, with Dr. Forbes' specifications, in japanned Metal Cases, 5s. 6d,, 6s. 6d. (fig. 3103). 3104 Chemical, Bath and Ward Thermometers, for particulars of various sizes and prices, see pages 153 and 159, and figs. A, B, and B*, next page. 3105 Thermometers for Drying Rooms and Hot Water Apparatus, see page 167. 3106 Disinfecting Thermometers, of various forms and size, as supplied to Government hospitals and other public institutions, see page 169. 3107 Improved Dropping Bottles, for Solutions of Nitrate of Silver, Acids, or other Medical Preparations, &c., &c., (see page 192, fig. 449). These bottles made of glass, the stopper, which is carefully ground in, being formed of stout barometer tube drawn out to a point ; over the stopper and neck is fitted a glass cap, also ground so as to be air-tight. The bottle being about two-thirds filled with the fluid to be used, is held in the hand inverted (the cap having been removed, when the warmth of the hand will expand the confined air, and expel the fluid through the perforated stopper, drop by drop. These Dropping Bottles have been found very useful both for Medical, Chemical, and Photographic uses. Price Is. 6d. each, or in turned wood pocket case, 3s. 3108 LOWE'S TEST FOB SEWAGE IMPUBITT IN WATER. Mode of using the Test. Break one of the glass balls by dropping it from a height of a foot into a clean wine glass. Fill the wine glass with the water to be tested. The more dangerous kinds of impurity ammoniacal products derived from sewage if present in considerable amount, are at once detached, by the production of a yellow colour, or by a flocculent deposit, which becomes yellow or greenish after standing six hours (the glass being covered to exclude dust). Water of this description is unfit for use. If a copious white precipitate forms, or if any cloudi- ness ensues, the water should be submitted to analysis, and should in no such case be drunk without previous boiling. If the water remains perfectly clear it may be used with safety. Price, 2s. 6d. per dozen. The greatest care should be taken that the wine glass, containing the test and broken glass, be emptied after using, and thoroughly cleansed, the Test being poisonous. tfEGRETTI AXU ZAMBEA, HOLBORN VIADUCT, E.G., FIG. 3103. Eacn. s. d. Each. s. d. 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 Improved Dropping Bottles, Set of 12 in case (fig. 3109) 150 Stethometer (Dr. Quain's), for ascertaining the expansion of the chest ...... 1 10 Dentists' Mirrors, with powerful Magnifier, and hinge- joint, to make them portable . . . from 1 10 Optometer (Smee's), for testing the Vision, and arranging lenses to supply any defect ... 550 Complete Sets of Trial Sights, having 36 pairs of Convex, and 36 pairs of Spherical Lenses, 18 Convex and 18 Concave Cylindrical Lenses, 12 Prisms, 2 Black Discs, 4 Discs with small apertures, a series of Tinted Glasses, and a Graduated Adjustable Frame in which the various Trial Sights are held 1 11 10 10 2 16 by springs. Complete in Mahogany Box Eye Shades, covered with Silk, Black or Green colour . Occhiombra or Transparent Eye Shades, with case Nitrous Oxide Gas Apparatus, for Dental operations, complete with pure compressed gas, face-piece, two- way stop-cock, &c., &c Electrical, Galvanic, and Electro -Magnetic Apparatus, for Medical Use. See pages 455 and 459. Sick Room or Invalid's Telegraph and Signal Bell, see ante, page 461. 10 10 16 16 45, COENHILL, E.G., AND 122, REGENT STREET, W., LONDON. 503 FIGS. 3119. 3119 Urinometers and Apparatus connected with their use, figs. 3119, also see pages 191, 192. 3120 Galvanic Batteries, in series, either Grove's or Bunsen's, arranged for igniting a Platinum Wire of sufficient length for applying Actual Cautery, with convenient Directors (Ecraseurs) and appliances for Surgical Use, &c., &c. 8 8 to 12 12 0, and supplied to order. See also page 455. 3121 Galvanic Apparatus, for supplying a constant battery current with 30 or 50 Leclanche Cells. 1010 1313 3122 Stethoscopes. Enema Apparatus. Breast Pumps, Stomach Pumps, Injecting Apparatus. Pravaz's Hypodermic Syringe. Sphygm ograph with improve- ments. Laryngoscope and Lamps for use with ditto. Cupping Instruments. Spray Producers, G~as Inhalers, (various), Respirators. Hearing Trumpets, Voice Conductors or Conversation Tubes. Gas Table Furnaces, and Enamelled Iron Evaporating Dishes for Pharmaceutical purposes, &c. Various forms and prices^ with all recent improvements, to order. 3123 COLLECTIONS OF MINERALOGY AND GEOLOGY. MINERALS. 100 Well defined specimen Minerals, in Cabinet 200 Ditto ditto 500 Ditto ditto larger . 500 Ditto ditto larger s. 1 10 2 10 7 7 10 10 d. s. to 3 3 to 7 7 to 10 10 to 50 All with name and locality, and arranged according to Dana's Mineralogy. FOSSILS. 100 Fossils, British and Foreign 200 Ditto ditto 300 Ditto ditto 500 Ditto ditto 1000 Ditto ditto 1 10 2 10 6 6 10 10 25 to 3 10 to 7 7 to 10 10 to 30 to 60 Arranged stratigraphically with name, geological position, and locality of each specimen, KOCKS. 100 Kocks, British and foreign 1 10 to 3 10 200 Ditto ditto 2 10 to 7 7 300 Ditto ditto 6 6 to 10 10 500 Ditto ditto 10 10 to 30 According to size of Specimens. Von Gotta. All with name and locality, and arranged according to Collections for special departments of Geology and Mineralogy, Casts of rare Fossils, &c. &c MACHINERY FOR THE MANUFACTURE OF SODA WATER AND ALL OTHER KINDS OF AERATED AND ARTIF1CAL MINERAL WATERS. FiG. 3124. 3124 PATENT CONTINUOUS PROCESS SODA WATER MACHINE. This small but effective apparatus has all the good fittings requisite to render it perfect ; the Condenser takes apart ; the Agitator has an outside support ; it is fitted with a Dial Pressure Indicator, &c., and is complete in itself, requiring no extra stand or framing, being mounted on a cast-iron stand, as shown in the engraving, fig. 3124. This machine is capable of producing about 100 dozen large bottles per day. It comprises a strong Gun-metal Pump with valve box at the top ; a stout Copper globe, made to open if required, and fitted with blow-off valve, with connection for bottling machine : the Agitator driven by toothed wheels ; Solution pan, &c., mounted on framed stand ; a strong oak tub, iron bound ; Copper bell with blow-off cock at top, pipes and connections forming gasometer ; Stout Lead Generator, with tinned copper Agitator, gun-metal fittings and pipes ; syphon box and pipe for supplying acid to Generator, and all necessary requisites, including spanners to fit every bolt and nut. The whole mounted complete on cast iron frame, Price complete, ready for working, 36 Ditto for a larger size of above machine, complete with Gas apparatus, 70 and 85, to make from 600 to 1200 dozen bottles per day. Suitable Steam Engines for driving above supplied to order. Estimates given for complete sets of Mineral Water Machinery of the most recently improved construction. We advise Foreign Correspondents to utilise vacant space in the Packing Cases by having them filled with Corks, thereby saving Freight. An Illustrated Pamphlet sent with each Machine, containing full instructions for working them, and Recipes for making Soda Water and all Aerated Beverages. 45, CORNHILL, B.C., AND 122, KEGENT STREET, W., LONDON. IMPEOVED DIVING APPAKATUS. FIG. 3125*. FIG. 3125. FIG. 3125f. 3125 Improved Diving Apparatus, for the recovery of Sunken Ships, &c., Building or Repairing Bridges, Pearl fishery, Sponge Diving, or any other Submarine operations. The engraving (fig. 3125) shows the general arrangement of the Diving Apparatus when in use : A Diver equipped in Water-tight dress, Copper Helmet with Glass Eyes, Boots with leaden soles, &c., figs. B Tube for supplying Air to the Diver. c Signal or Life-line. D Attendants at Signal-line. E Three-Barrel Atmospheric Air Engine (see also fig. 3127 next page.) F Ladder- line, for use in Thick Water. G Rope Ladder for Descending and Ascending to and from the vessel. H Weight to steady^ the Ladder. I Diver stopping a Leak under the Water-line. Anchor, Guns, and Chain Cable to be slung and hoisted up to surface. By the .improvements now introduced, a Diver may remain hours under water without inconvenience. With each Apparatus there is sent a Book containing a separate illustration and description of every part of the Air-Pump, Tubes, Helmet, Dress, &c. ; so that when taken entirely apart, any person can put it together in thorough working order ; also full and detailed directions for its use, and how to keep it always in good working order, it being in every respect effective and complete. Price for Improved Diving Apparatus 140 to 230. 3126 Sub -marine Lamp (Denayrowze) large size Ditto ditto, small size . price 22 13 506 NEGKETTI AND ZAMBRA, HOLBOEN VIADUCT, E.G., 3127 Treble Barrel Air Pump (fig. 3127) for the Diving Apparatus, of sufficient power to send down a plentiful and continuous supply of air to the Diver. A Condensing Chamber. B Dial Indicator, denoting depth of water and pressure. The Diving Apparatus consists of a powerful treble-barrel air-engine (fig 3127), gun-metal cylinders, wrought-iron crank, fly-wheel and handles, spanners, tinned Copper Helmet with segment-screw;joint,lead weights, vulcanised tube, metal unions, two diving dresses, suitable warm clothing, boots, signal line, ladder-line, &c., &c., complete, in strong and secure packages. This Apparatus possesses the following advantages : 1. Should the Diver wish to raise himself without signalling the attendant, he can do so by simply placing his finger on the valve, which afterwards rights itself. 2. Without assistance he can open his own Helmet, which is so constructed that the front eye can never be lost, or become tight. 2. The Indicator always denotes the depth the Diver is at. 4. The condensing box secures a more continuous stream of air. 5. It also has a copper cooling cistern, for great depths. Directions for use, and keeping in repair, se:it ivith each Apparatus. 45, CORXIIILf,, E.G., AND 122, BEGENT STREET, W., LONDON. 07 IMPROVED ICE MAKING MACHINE, (Continuous Direct Acting.) 3128 For producing Ice of the Clearest and Purest Description, in quantities of from 2 cwt. to 20 tons per day, at the most economical rate. For description see next page. 508 NEGEETTI AND ZAMBKA, HOLBOEN VIADUCT, E.G., 3128 The Continuous Direct-Acting Ice Machine, (fig. 3128), with Vertical Engine and Air Pump, as shown in wood engraving, including Condenser, Refrigerator, Ice Chamber, and all necessary pipes and connections complete, ready for working, price 180, delivered in London. Boiler and Fittings suited for above apparatus, price 46. Stout Packing Cases about 10 extra. Special Quotations given for Larger Machines. By the evaporation of -ZEther a great degree of cold is produced, which absorbs from surrounding objects with which it is brought into contact a large amount of latent heat, causing a degree of coldness to them. Upon this principle is based the workingpf the|Ice Machine, and to fully utilize the complete cooling'power of the evaporated ^Ether the following machinery is employed, consisting of four primary parts : The ^Sther Pump, to accelerate the evaporisation of the JEther, as well as to remove the vapour when produced, is placed in connection, by means of pipes, with two chambers, named the Refrigerator and the Condenser (see Fig. ), which are made of copper, and consist of a series of tubes. The air is exhausted from these by the jEther pump, and the Refrigerator then charged with JEther, which surrounds the outside of the tubes referred to. The ./Ether pump is then set work- ing, causing the evaporation and removal of the ./Ether vapour, and cold is instantly produced, during which time a current of incongealable liquid (brine) is passed through the tubes of the refrigerator, and by the absence of heat in the Either vapour, this liquid is rapidly cooled and becomes an agent for " transmitting the cold." This is then conveyed to and circulates in the ice chamber (containing ice- moulds) filled with fresh water to be made into ice, cooling in its turn the water in these moulds. When the cooling agent has thus traversed, abstracting heat from the water to be frozen, it is returned to the refrigerator to be re -cooled by passing through the tubes, the heat again abstracted from the cooling agent, which as before is circulated round the ice-moulds, and is thus -kept moving until ice is produced therein. The ./Ether vapour drawn from the refrigerator is passed into the condenser and into a tubular chamber immersed in water ; the heated vapour then enters these tubes, and from the temperature of the water around them being much lower than that of the vapour it quickly reduces the ./Ether vapour into its liquid nature, as originally put into the refrigerator, and where it is again returned for re-evaporation. The process is exceedingly simple, and can be readily under- stood, and may be carried on using the same ^Ether and cooling agent for months without appreciable loss or deterioration. These machines will produce ice in large slabs from six inches thick and upwards, if required, but the tedious process accompanying the formation of ice beyond six inches thick is a great drawback. Large blocks also necessitate much labour in moving from the ice-box, as well as occupying considerable time in cutting up into small blocks, items which enhance the cost of production, and thus affect the profits. The great advantage of machine-made ice over the natural ice is that it is purer, harder, and equally transparent, admitting of longer and closer storage, being made in blocks, and can be made for half the value of imported ice, the cost of production varying from 5s. to 10s. per ton, according to the size of the apparatus employed, a large machine producing it at much less cost than the smaller size. 45, COBNH1LL, E.G., AND 122, REGENT STREET, W., LONDON. 509 The construction is reduced to the greatest simplicity, and requires only a few minutes to comprehend. The Boiler is made of the best Staffordshire plate-iron, its strength tested to 120 Ibs. upon the square inch, and it is complete with all the usual fittings. No foundations are necessary. The space occupied is about 6| feet long, 4 feet wide, and 5| feet high. It is sent out ready for working, with a set of stoking-irons and 6 feet of Iron chimney. The expense of working the Apparatus is the attendance of one person, and about 10 Ibs. of coal hourly or its equivalent in wood fuel. Drawings, with book of reference and instructions, are supplied with each Machine. It is advisable to have a spare set of Valves and Springs, these being the chief parts of the machinery influenced by constant wear and tear ; also duplicates of other parts liable to derangement should be separately ordered with the apparatus, when for export, the cost averaging about 12. Price of ^Ether for use with Ice Machine, per gallon, 12s. 6d., in sealed Metal Cans and cases specially prepared for export. Price of Cans holding 4 gallons of JEther, fitted with Gun Metal Screw Caps, made extra secure against leakage, 12s. each. FIG. 3132. FIG. 3130, HYDRAULIC MACHINERY. 3129 Portable Proving Pumps, for testing Boilers, Tubes, &c., with discharge Tap and Union, mounted on a strong Iron pail, complete, with Gauge to test to 200 Ibs. per square inch 770 880 3130 Hydraulic Press Pump, (Bramah Pattern, fig. 3130). This Pump is fitted with Safety and Relief Valves of the most improved construction, and has been found by experience to be most convenient and durable, and not liable to get out of order under the most severe strains . . . 25 3131 Hydraulic Press Pump of larger and stronger pattern 28 Extra for knuckle joint, sleeve and pin for working the above Hydraulic Presses by Steam Power, 3 10 3132 Hydraulic Presses, of various sizes, adapted to different purposes, with Horizontal Pump attached direct to the press. The bed of the press serving for a cistern. These Pumps, as shown in fig. 3132, are provided with relief and safety valves, &c., of the best workmanship. Price, 36 50 80. Power of these Presses 15 to 100 Tons. 510 NEGKETTI AND ZAMBEA, HOLBORN VIADUCT, E.C., GAS MOTOBS. THE NEW PATENT 5-MAN POWER VERTICAL "OTTO" GAS ENGINE, VERY SUITABLE FOR DRIVING SMALL ELECTRIC INSTALLATIONS, AMATEUR WORKSHOPS, PUMPING WATER, &C., &C. 3133 Gas Consumption. This Engine (fig. 3133), has been designed to meet the demand for a small Gas Engine that will consume G-as only at the same rate as the " Otto ; " the smallest " Otto " Engine hitherto supplied being too large for many who want power. Power. The Engine will give off one horse-power on the pulley ; but, of course, the consumption of gas is in proportion to the power required ; and if, say only one man-power is taken from the Engine, the Governor will cut off the gas to suit. This Engine is really well made. The crank is of steel, and other materials of the very best are used. All working parts are easily replaceable, and are made strictly to gauge. Unlike most small Gas Engines of other makes, it is fitted with a sensitive and patent Governor. It stands in a space of about 3ft. square by 4ft. 8in. high. Lithographed Foundation Plans, giving Sizes of Pipes, Meter, &c., are supplied, together with a Book of Instructions for Working." Each Engine is sent off erected almost complete, only the Fly-wheel and Pulley being detached. Price 45, with one set of Yalves. (Water Yessel, 20s. extra.) 3134 The 5-Man Power Vertical " Otto " Gas Engine is also constructed in com- bination with a Dynamo Electric Machine, capable of working 6 to 8 Incandescent Lamps. The Dynamo is connected to the Engine by a simple mechanical arrangement, so that when not required for lighting it can be quickly thrown out of gear, and the Engine made available for other purposes. Our engraving (fig. 3134), shows on an enlarged scale the 5-Man "Otto" Engine with the Dynamo Machine attached. Price, complete with Dynamo Electric Machine, as fig. 3134 . 75 3134* Ditto ditto, without the Dynamo 45 Estimates given for larger and more powerful Gas Engines. 45, COKXHILL, E.C., AND 122, EEGENT STIIEET, W., LONDON. 51 L The Patent 5-Man Power Vertical" Otto " Gas Engine (fig. 3133), is admirably adapted for amateui use, takes up but little floor space, Yery Silent in action. No extra Insurance charged by leading Insurance Companies. No regular attendance required beyond oiling, cleaning and starting. Great economy as compared with small Steam Engines. FIG. 3134. The 5-Man Power " Otto " Gas Engine, with Dynamo Electric Machine (fig. 3134). 512 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., NEGRETTI & ZAMBRA'S IMPROVED PORTABLE HELIOGRAPH, (fig. 3135). Instructions for use. In setting up this instrument the legs must be first set up, then the long arm (which carries sighting vane) put on and lightly clamped. The instrument can then be firmly screwed on the tripod. The centre is fitted tightly in socket of staff - head, which is of simple construction, especially designed for this Helio- graph, with the milled head for horizontal motion on the left hand when mirror is facing distant station the length of flash can be regulated by means of capstan screw on saddle piece over the lever arm. As all the important screws are capstan heads they can be tightened by the capstan pin. TO USE THE HELIOGRAPH. Sighting with Sun in front of Signaller. The usual method of directing the flash to the required point has been to look through the mirror FIG. 3135. from the back and move the sighting vane until the sighting point is exactly in line, but a simpler and very accurate way is to stand in front of but a little on one side of mirror, and looking into it bring the mirror, by means of horizontal and vertical screws, into such a position that the spot in centre of mirror cuts off the reflection of distant station; then move the sighting rod until the reflected image of sighting vane come into an exact line with the sighting vane and distant station. The flash is then thrown on to the vane (which must be firmly clamped and not shifted), and is rightly aligned when the dark shadow spot from centre of mirror is thrown on vane. The mirror must be moved up and down to the right or left until the spot falls on the vane it is then ready for use. Sighting with Sun behind the Signaller. When it is necessary to use both mirrors, place the signalling mirror facing the sun and the auxiliary mirror inclining to the distant station, stand in front of the Heliograph and looking into the mirror, so that the whole of the auxiliary mirror can be seen reflected. Move the latter horizontally or vertically until the distant station, the spot on the auxiliary mirror, and the unsilvered spot on the signalling mirror are in the same line ; the auxiliary mirror can then be firmly fixed in its socket, and the mirror clamped with the nut at the side. In signalling the left hand is kept on the milled head and the right on the signalling key, the necessary adjustments to suit the motion of the earth, and keep the shadow spot on the sighting vane, can thus be made while in the act of .signalling without interruption or delay. For prices, see page 348. (No. 1735.) 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 513 3135 Dip Circle, or Inclinometer, Kew Pattern, recently improved, with Lloyd's total force Apparatus, including verification (fig. 3135) Price 40 N.B. Price quoted for Dip Circle on page 131 is an error, should be 40 . FIG. 3135. FIG. 3136. 3136 Unifilar Magnetometer, Improved. Kew arrangement (fig. 3136), for accur- ately ascertaining the horizontal component of the earth's magnetic force and also the declination, including verification . . . 70 2L 514 NEGJ1ETTI AND ZAMBRA, HOLBORN VIADUCT, E.G. 3137 Fox's Circle or Inclinometer, as used on board of H.M.S. Challenger, and most Arctic Expeditions, for testing Terrestrial Magnetic force 38 3138 Kew Constants Computed . 220 3139 Thomson's Water Dropping Collector, supplied to order. 3140 Collecting Fuse, do. do. 3141 Portable Astatic Galvanometer, in brass case, with jewelled centres, having a resistance of about 1000 ohms, with controlling Magnet. In Sling Leather Case 5 10 3142 Thomson's Portable Electrometer, (attracted disc) fitted with Electrophorous in polished Mahogany Cabinet , 12 12 3143 Morse Ink-recording Telegraph Instrument, or Direct Ink-writer, consisting of a train of wheelwork driven by a spring. Transmitting key, galvano- scope, and commutator, &c., for terminal station correspondence mounted on polished Mahogany ...... 21 3144 Morse Ink-recording Instrument, with key, two galvanoscopes, commutator, &c., for intermediate stations, mounted as above . . . 23 3145 Phonoscope, with Reiss' interrupter, for illustrating the principle of the Telephone, and showing the effect of sonorous vibrations on electrical discharge in vacuum tubes 880 3146 Long Glass Yertical Gas Jet for Singing Flame . . . . 14 3147 Glass Tubes, 4 tuned for above, with Clip Stand . . . . 1 5 Q 3148 Piezometer, to show the compressibility of liquids and liquefaction of gases under pressure with tubes . . 11 11 O 1 3149 Cailletet's Compression Pump, for liquefaction of gases, will give a pressure of 300 atmospheres, without table or accessories 28 10 3150 Ditto ditto, for 1000 atmospheres pressure . . 48 3151 Ditto ditto, improved, producing liquefaction of 300 or 400 grammes of Carbonic Acid per hour . . 117 3152 Air and Water Compressing Pumps, for Testing Boilers Gauges, &c., &c. Supplied to Order. U53 APPARATUS FOR LIGHTING GAS in Public Buildings, specially con- structed as required. Estimates given for fitting up Electric Bells, &c., in Mansions, Hotels, Ships, &c. Also for Speaking Tubes. TELEGRAPHIC TESTING APPARATUS, &c. 154 Resistance Coils Wheatstone's Bridge Relays Lightning Protectors ondensors Switches, &c., &c., to order. 45, CORNHILL, E.G., AND 122, REGENT STKEET, W., LONDON. 551 FlG. 3135 3155 Eain Gauge, for "Water "Works, Mountain, or Tropical Service, 8 Inches diameter, with Vertical Cylinder about 6 inches above the receiving funnel to prevent splashing, and specially to collect and Measure Snow. Extra large receiving vessel holding about 48 inches of Bain-fall strongly made to resist extreme temperatures, with Graduated Glass measure reading to hundredths of an Inch. Stout Copper, (fig. 3155) including Graduated Measure 4 10 FIG. 3156 3156 Observatory Standard Barometer of the highest class and precision (fig. 3156 See also pages 1 to 11) 35 See also Meteorological Section, pages 1 to 131. 2L2 516 NEGBETTI AND ZAMKRA, HOLBORN YIADUCT, E.O. 3157 SIR WILLIAM THOMSON'S IMPROVED TIDE GAUGE, (fig. 3157; For general description, seepages 121 and 122 . . price 90 45, CORNHILL, B.C., AND 122, EEGENT STREET, W., LONDON. 517 PHOTOGRAPHIC APPARATUS- 7557. PRIZE MEDAL awarded to NEGRETTI AND Z AM BRA, , 1855. Honourable Mention, Paris. The Austrian Gold Medal. For Stereoscopic Photographic Views upon Glass. 1862. TWO PRIZE MEDALS, " For many important Inventions and Improvements. Together with accuracy and excellence in objects exhibited." FIG. 3159. FIG. 3160* FIG. 3158. NEGRETTI AND ZAMBRA'S IMPROVED SERIES OF PHOTOGRAPHIC LENSES. 3158 View Lenses (Fig. 3158) plate (4 by 3J) ..... i (6by4f) ..... . 1 (8iby6|) ..... with Rack Adjustment, plate . JJ JJ M >J JJ 2 JJ 3159 Rapid Rectilinear Lenses, for Yiews or Portraits (Fig. 3159) \ plate . jj jj jj ,, 10 by 8 plate 12 by 10 . 15 by 12 . 18 by 14 . 3160 Portrait Lenses (Fig/ 3160) Eack-work Adjustment $ plate . Instantaneous Shutters of all kinds supplied to order. P. a. 10 6 110 220 150 1 15 220 330 550 880 990 11 11 14 14 1 15 3 15 8 15 518 NEQRETTI AND ZAMBRA, HOLBOEN VIADUCT, E.G., PHOTOGRAPHIC LENSES AND PRISMS MADE BY C. A. STE1NHEIL SOEHNE, MUNICH. Sole Agents NEGRETTI AND ZAMBRA, LONDON. NOTICE. This List is a translation of Messrs. Steinheil's Catalogue. The exact equivalent focus is not guaranteed, as differences in refraction and in the thickness of the lenses have to be corrected. N. and Z. will supply any instrument of C. A. Steinheil Soehne's make, at their catalogue prices, plus the carriage expenses from factory. In order to meet the various requirements and to ensure in each special case as perfect work as possible we make lenses of different constructions. The present catalogue comprises six different classes of photographic lenses the capabilities and object of which are given in the order of their respective rapidities. Departing from the order observed in our former catalogue, the lenses are not numbered consecutively in the present one, but are divided into Series. Each series commences with No. 1 and continues upwards. To avoid errors it is necessary in ordering to quote both the No. of the Series and the No. of the lens in the present catalogue. To facilitate finding the distances of the subject and also of the focussing screen (ground plate) from the lens in reducing or enlarging, we have compiled tables which are sent with every lens. Our different Antiplanets and Aplanats are free from disturbing reflections, and thus enable their employment for all purposes in the open air and for taking strongly illuminated subjects without producing flare or light spots. They are strictly corrected for spherical errors and chemical focus, and they give evenness and correctness of lines (without distortion) combined with equality of definition over the whole of the picture. In " focussing " with these lenses it is advisable to use the largest stop, even, when it is intended to work with the smallest. We make a special point never to supply a lens which is capable of improve- ment, and for this purpose we test them all before sending them away. The scientific basis of our establishment and the precise methods employed (the same in the manufacture of astronomical and photographic lenses) enable us to produce lenses of such uniform accuracy that we are unable, even with all the means for rigorous testing at our command, to detect the slightest differences. Our photographic lenses, of which we give full description in the following pages, consist chiefly of two classes, viz. Antiplanetic and Aplanatic. 45, COKNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 519 ANTIPLANETIC LENSES. Patented in Germany (No. of Patent 16354), England and America. By means of these recent combinations, we have succeeded in correcting to a considerable extent the hitherto greatest defect in Photographic Objectives, viz., " Astigmatism," and with the consequent rapid decrease of definition from the centre to the margin of the picture. This advantage we have obtained by designing a special combination, differing widely from the usual forms. It consists of two entirely different halves, each of as great and diametrically opposed errors as possible. The foci are therefore different, and whilst the anterior lens has a shorter focus than the whole objective, that of the posterior lens is negative. The above arrangement enables us to produce an objective which, whilst retaining the qualities of a good instrument, embodies the additional advantage of having " less astigmatism," by which greater sharpness and depth are produced and distributed thereby more equally over a larger and strictly even picture, before any decrease in definition is perceptible. Illumination, too, is more evenly dis- tributed in consequence of the lenses being proportionately nearer to one another. The perfectly correct delineation produced by these " Antiplanets," renders them particularly suitable for enlargements. If small and very sharp originals are taken, and subsequently enlarged, depths are obtained, which, in larger pictures taken direct with the same amount of light would be unattainable ; for this purpose (which probably will play an im- portant part in photography), the Antiplanets are specially suitable. The same objective may be employed for direct work, and for enlargements, but in the latter case, the front lens of the Antiplanet should be turned towards the enlarged picture, and the back lens towards the object to be enlarged. This construction is designed for strictly even and correctly delineated pictures, and all tilting of the Camera should be decidedly avoided, and a movable lens used instead. Note. TheJLensesof Series I., II., III., IV.,' and VI., have "Waterhouse Diaphragms. V., have Rotating Diaphragms. 3161 SERIES No. 1. ANTIPLANETIC LENSES FOR PORTRAITS. The rapidity is the same as in the usual Portrait Objective, but there is more equality in the distribution of sharpness and illumination over the picture, and greater depth. These advantages combined render the lenses of this series specially suitable either for Portraits or for enlargements. They consist of two pairs, of which the anterior is cemented as positive, and the posterior is separated from the former, and negative. 1 No. Diameter of Front Lens. Focal Length. Size. Price. Inches. Millimet. Inches. Cent. s. d. 1 I 16 2 5 Busts Locket Size 2 17 6 2 3 76 9| 24 C-de-V's 12 15 3 S| 92 12| 32 Cabinet 23 4 5 T 6 o 1-34 23f 50 Piomenade 46 Special Quotations for Larger Sizes. 520 NEGRETTI AND ZAMBRA, HOLBOEN VIADUCT, E.G., SERIES No. II. 3162 ANTIPLANETIC LENSES FOR GROUPS. (About double the rapidity of the Aplanats in Series III.} These are for taking Portraits in a good light; also Groups, Architecture t Landscapes, etc., etc. ; they have a greater depth and larger field, with more equal definition and illumination than the lenses of Series I. The Group -Antiplanets are an improvement over our Group -Aplanats, and possess all the advantages which can be fairly expected in a good objective simultaneously and therefore render them suitable for the various uses in the open air (en-route") and in the studio. They consist of two cemented pairs placed so closely together that there is only just room for the diaphragm. No. Diameter of Front Lens. Focal Length. Inch. Millim. Inch. Centim. Price. 1 H 17 8| 9-5 4ix 3J s. d. 2 15 2 i 25 Sy-i- 14-4 From 4 x 3 to 5x4 3 10 3 i T 5 _ 33 7i 18.4 5 x 4 to 6|x 4f 4 15 4 Hi 43 24-0 6^x 4| to 8Jx 6| 600 5 l* 48 10} 27-5 8i x 6i to 10 x 8 7 10 6 64 14 JL 36-0 10 x 8 to 12 xlO 12 7 ** 78 17* 44-0 12 x 10 to 15 x 12 18 5 3163 SERIES No. III. APLANATS. These lenses are already well and favourably known for the good pictures they give and their adaptability for either Architecture, Landscape, or even for Group Work in the open air. The aperture to focus is as 1*7, angle about 60. No. Diameter of Front Lens. Focal Length. Inch. Millim. Inch. Centim. HlftAO Vft J. 1UUIAJ.C CtUUUJ-UlJJg W OLVJJ U.OCU.* i ric6. 1 4 7-0 |f 4-1 For enlarging s. d. 220 2 A 158 4 9-5 44 x 34 220 3 I 8 24-8 5| 14-2 From 4J x 3J to 5x4 300 4 1| 31-6 71 189 5 x 4 to 6^x 4f 3 15 5 * 42-9 11 27'7 6^ x 4f to 8^ x 6^ 550 6 51 9 ]4 35'9 8^ x 6^ to 10 x 8 6 15 7 2f 60-9 17- 44 10 x 8 to 12 x 10 10 5 8 2H 74-5 21 T 3 - 53-8 12 xlO to 15 x!2 15 9 88-0 25 10 63-6 .. 15 x 12 to 18 x 16 20 10 4^ 115-0 33 83'9 18 x 16 to 22 x 20 29 5 45, COENHILL, E.G., AND 122, REGENT STREET, \V., LONDON. 521 3164 SERIES No. IV. LANDSCAPE APLANATS. (Angle about 75). This class of Aplanatic Lens is specially constructed for Landscape work, but can also be advantageously used for copying ; effective aperture T V TT ; the field is even greater than in the Aplanats of Series III., so that with equal size of plate and corresponding number of Aplanat, subjects are obtained of sharp definition in the margin, which are not perceptible with lenses of Series III. No. ofoTLe r ns. 1 Focal Length. Inch. Milliin. Inch. Centim. 1 fV 5-5 2| 5-8 From 2 x I* to 3 x 2f s. d. 200 2 1 9 3 7-7 1\ x 2 to 4x3 2 10 3 -4 12 4| 12-2 3f x 3 to 6 x 4| 300 4 H 17 61 16-2 5x4 to 8x6 3 15 5 H 23 9* 24 7 x 5 to 11 x 8 550 6 We 36 .15| 39 10 x 8 to 13|xll 10 5 7 2* 54 23| 60 14 xll to 20 x!6 20 In Landscape work it is frequently desirable to take the same subject in various size pictures from the same spot, and this is only attainable by the employment of objectives of different foci. For this work we have arranged a number of objectives in "sets," for which purpose the lenses of Series IV., owing to their closeness to one another, are most suitable. All the lenses of these sets fit into the same flange by means of a bayonet hinge, and each set is provided with a combination of five diaphragms or stops. Set of four Landscape Aplanats, each of the same aperture of lens, 15-16in. (23 millimetres), but varying foci, say 9|, 12f, 15f, 19 inches (24, 30, 40, and 48 centimetres) in lock-up case; size of picture with full aperture, 6^f by 5| inches (17'5 x 13'8 centimetres), with smallest diaphragm, 11 X 7 inches (28 X 20 centimetres.) Price 20. Note. Sets of any number and class of Aplanats made to order at proportionat 6 pric es . SERIES No. Y. 3165 WIDE-ANGLE APLANATS FOR INTERIORS, ARCHITECTURE JH AND LANDSCAPES. Effective Aperture ^ ? of their foci. The proportionately short focus and the large angle (about 100) of these lenses make them particularly adapted for interior work and for very high broad objects taken from short distances. By reducing the amount of light, an increase of " Sharpness," depth and angle of field is obtained. 522 NEGRETTI AND ZAMBRA, HOLBOBN VIADUCT, B.C., Diameter of Front Lens. Focal Length. Size of Picture. No. Inches. Millim. Inches. Centim. Inches. Price. 1 7o 5-5 3f 9-6 5x5 300 2 A 7 41 12-1 7x7 300 3 TV 10-5 n 18-2 1(H * 10i 500 4 A 14-5 10f 262 12* x 12 J 7 10 I Special quotations for larger sizes. 166 SERIES No. VI. WIDE ANGLE APLANATS FOR COPYING, With a rapidity which is equal to Series V., these lenses give perfect flatness of picture and sharpness of definition, and have, at the same time, a considerable field. These qualities render them suitable for copying Maps, Charts, Pictures, Engravings, &c., &c., &c. For inverting work for the printing process, we have designed the prisms contained in Series VII. Diana, of Front Lens. TJj-i Focal Length. .Size of Picture. Pn'po Inches. Millim. Inches. Centim. Inches. s. d. 1 I 25 14| 36-5 10 X 10 900 2 1* 30 18 45-7 13iXl3J 12 10 3 itt 43 23| 60-1 17 X 17 17 5 4 2^ 63 38| 97-5 23| X 23f 40 5 m 75 48* 122-4 27 X 27| 70 6 3 T 9 a 90 56 142-3 3Hf x 33f 100 Special quotatitns for larger sizes. As a result of our experience, we beg to point out particularly the necessity of avoiding the slightest vibration during exposure with these wide angle Aplanats. The passing of a cart, the working of a press on a contiguous floor, the marching of soldiers in step, have been quite sufficient to affect that sharpness of picture which is otherwise attainable with these objectives. In taking fine even objects, it is advisable not to use too small a diaphragm, as the diffraction caused thereby veils the picture. 3167 SERIES No. VII. PRISMS. These prisms are all right angle, with silvered hypothenuse ; they are centred in their mountings, and adjustable to the lens by means of a screw in place of the front ring of latter. To obtain parellelism between the anterior side of the prism and the object, they are provided with an arrangement to turn the prism round its axis and to clamp it in any position. 45, COENHILL, E.G., AND 122, REGENT STREET, W., LONDON. 523 [No. To work with Lenses, as follows : Price. 2 3 4 5 6 7 8 9 10 11 12 Ser. III., No. 2, Ser. IV., No. 3, Ser. IV., No. 4, Ser. V., No. 1. Ser. V., No. 2, Ser. V. No. 3, and Ser. V., No. 4 Ser. IV., No. 5, and Ser. VI., No. 1 Ser. III., No. 3, and Ser. VI., No. 2 . . . . '. Ser. II., No. 2, and Ser. HI., No. 4 Ser. TV., No. 6 . . . Ser. II., No. 3, and Ser. VI., No. 3 Ser. III., No., 5, and Ser. VI., No. 4 Ser. IV., No. 7 Ser. II., No. 4, Ser. III., No. 6, and Ser. VI., No. 5 '. Ser. VI., No. 6 . Ser. III., No. 7 Ser. III., No. 8 s. d 4 15 550 5 15 750 8 15 10 10 13 15 17 5 21 5 25 15 40 5 -0 69 Each Prism is accompanied by a short description of its use, with wide angle Aplanats. SERIES No. VIII. 3168 APLANATIC FOCUSSING LENSES. These are a combination of three Lenses, so constructed that, at a considerable focal distance and large field, they produce an even, undistorted picture, achromatic, both in and outside of the axis. No. Equivalent Focus. Magnifying Power Lineal. Price. Inches. Millim. 1 2 2| If 60-9 40-6 About 83 times. About 5 times. s. d. 1 10 150 FIG. 3169. P. ZSCHOKK'S PATENT PNEUMATIC SHUTTER. FOR INSTANTANEOUS PHOTOGRAPHS. 3169 Messrs. Steinheil make these Shutters for all sizes of Lenses. Price including tube for Lenses up to 4 Inches (108 Millimetres) diameter of Lens, measured at the part on which the wooden flange M N is adjusted (see fig. 3) , . 3 12 Larger sizes supplied to order. 524 NEGBETTI AND ZAMBRA, EOLBOKN VIADUCT, E.G., EALLMEYER'S PHOTOGRAPHIC LENSES. Cash Prices of the principal Lenses, including Diaphragms. PORTRAIT LENSES. 3170 EXTRA RAPID (c) FOR CHILDREN. 2 c 2f inches diameter 41 inch focus 15 15 3c 31 6 inch ......... 26 5 3171 QUICK ACTING (B). distance. 1 B For Cards . . 2 inches diameter 12 feet . ; . 650 1 B (Long) . 21 14 feet . . . 6 15 2 B Ordinary Cards . 2f 18 feet . . . 12 16 2 B Patent . 2| 18 feet . . . 13 5 SB for Cabinets 31 18 feet . . . 20 4B 41 25 feet . . . 40 3172 ORDINARY INTENSITY (A). 1 A Patent For Cabinets, in short rooms, -diam. 2| in., distance 14 ft. . 13 2 A Patent For Cabinets up to 8 by 61, diam. 31 in., distance 20 ft. . 18 3 A Patent For Cabinets up to 9 by 7, diam. 4 in., distance 24 ft. . 27 5 4 A Patent For Imperial Portraits and 10 by 8. diam. 41 in., focus 14 in. .... 38 10 5 A Patent For Plates 15 by 12 and under, diam. 5 in., focus 18 in. . 50 6 A Patent For plates 20 by 16 and under, diam, 6 in., focus 22 in. . 60 3173 PORTRAIT AND GROUP (D). 3 D Patent Portraits 81 by 6|, Views 10 by 8, diam. 2 in., focus lOfc in 9 10 4 D Patent Portraits 10 by 8, Views 12 by 10, diam. 2 in., focus 13 in. 13 10 5 D Patent Portraits 12 by 10, Yiews 15 by 12, diam. 3 in., focus 16 in , 17 10 6 D Patent Portraits 15 by 12, Yiews 18 by 16, diam. 4 in., focus 191 in 26 10 7 D Patent Portraits 18 by 16, Yiews 22 by 20, diam 5 in., focus 24 in. 48 8 D Patent Portraits 22 by 20, Yiews 25 by 21, diam. 6 in., focus 30 in. 58 3174 STEREOSCOPIC LENSES. Patent Stereographic Lens, 4 in. focus 4 5 Ditto with rack and pinion , 4 15 No. 1, Quick acting Single Combination Landscape Lens, 41 in. focus 200 No. 2, Ditto ditto ditto, 6 in focus ... 250 Rectilinear Stereo. Lens, 2| in. focus . .... 400 45, COENHILL, E.G., AND 122, EEGENT STEEET, W., LONDON, 525 3175 VIEW LENSES. RAPID RECTILINEAR (PATENT). The best Lens for general use out of doors, and for Copying. Size of View or Landscape. Size of Group or Portrait. Equivalent Focus. Price, Eigid Setting. *5 by 4 in. 4J by 3^ in. 6 in. 4 10 8 5 5 8J 5 10 84 6* 6 5 , 11 700 10 8 8| 64 , 13 900 12 10 10 8 . 16 11 13 11 French size. 171 12 15 12 12 by 10 in 19J 15 18 16 15 12 , 24 20 22 20 18 16 , 30 27 25 21 22 20 , 33 32 3176 * To be had in. pairs for Stereoscopic Views. WIDE-ANGLE RECTILINEAR (PATENT). For Architectural Yiews in Confined Situations. No. Largest Dimensions of Plate. Back Focus. Equivalent Focus. i ' Price. *1AA 7J by 44 34 in. 4 in. 4 10 1A 84 6i 4f 6J , 5 10 1 12 10 6* , 7 , 7 10 2 15 12 74 , 84 f 10 10 3 18 16 11 , is ; 14 4 22 ., 20 14 , 154 , 20 5 25 21 17 , 9 , 30 3177 To be had in pairs for Stereoscopic Views. WIDE-ANGLE LANDSCAPE LENSES (PATENT). For Landscapes pure and simple. No. Size of Plate. Equivalent Focus. Price. 1A 5 by 4 54 in. 350 1 7* 44 7 3 15 2 84 64 84 4 10 3 10 8 10 5 10 4 12 10 12 700 5 15 12 15 8 10 5A 15 12 18 9 10 6 18 16 18 10 10 7 22 20 22 14 8 25 21 25 19 526 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., 3178 BOSS' POETEAIT AND VIEW LENSES. QUICK-ACTING C.D.V. LENSES. These Lenses give very rapid results with brilliancy and exquisite definition. To obtain the best results it is desirable to use the No. 3 when the Studio exceeds 20 feet in length. BRILLIANT DEFINITION AND GREAT RAPIDITY. Nos. . 1 2 3 Focus 4J-in. 4f-in. 6-in. Price . 5 15 6 10 11 10 3179 RAPID CABINET LENSES. These Lenses have all the sharpness and good qualities of the Portrait Lenses^ but, having a natter field, give better marginal definition. To obtain the best results it is desirable to use No. 3 when the Studio exceeds 20 feet in length. BRILLIANT DEFINITION AND GREAT RAPIDITY. Nos. . 1 2 3 Focus 6-in. 8-in. 10-in. Price . 13 17 10 19 10 3180 IMPROVED PORTRAIT LENSES. These Lenses give all the sh'arpness that can be optically obtained. They are admirably adapted for Half-lengths and Sitting Figures ; but for Full-lengths the ' Cabinet " and " Carte " series give a flatter field. Nos . 3 3A 4 6 6 Focus 10-in. 12-in. 15-in. 20-in. 24-in. Plate . 6i x 4f 8} x 6| 10 x 8 15 x 12 18 x 16 Price . 17 10 26 15 38 42 10 54 3181 UNIVERSAL LENSES. For Groups, Portraits, or Studies in the Studio, Interiors, Copying, &c, The "Universals " possess optical properties between ordinary Portrait Lenses and the Bapid Symmetricals ; but are not equal to either of these Lenses for their special work. They are, however, fair substitutes for both in cases where one Lens only is desired. Nos. . 1 2 3 4 5 Focus 8i-in. 10i-ih. 13^-in. 16-in- 20-in. Views 8} x 6* 10 X 8 12 X 10 15 X 12 18 X 16 Groups 7* x 4* 8X 6 10 X 8 12 X 10 15 X 12 Price . 7 10 900 12 10 16 10 25 Larger sizes to order. 45, COBNHILL, E.G., AND 122, REGENT STEEET, W., LONDON. 527 182 PORTABLE SYMMETRICAL LENSES. For Landscapes and Architecture. Since the introduction of Photography perhaps no lens for Landscapes and Architectural purposes has had so great a share of popularity as the Symmetricals. They are universally used by many of our most eminent photographers. This is, doubtless, attributable to their extraordinary definition and flatness of field, as well as to the exceedingly portable form in which they are constructed, the series fitting the same flange. Nos. . 1 2 3 4 5 6 7 8 9 10 Focus 3- in. 4-in. 5-in. 6-in. 7-in. 8-in. 9-in. 10 in. 12-in. 15-in. Plate 3 X 3 4x3 5x4 7ix4i 8x5 8ix6i 9x7 10x8 12 x 10 13x11 Price 3 3 5s. 3 10s. 4 5 6 8 9 9 10 3183 UNIFORM RATIO OF STOPS. INTERMEDIATE STOPS SUPPLIED IF REQUIRED. Nos. . . 1 Ratios . / 2 22-6 3 32 4 / 45-2 5 64 These Lenses are supplied accurately paired for Stereo, purposes. 3184 RAPID SYMMETRICAL LENSES. For Groups, Views, Interiors, and every kind of Outdoor Photography. The Rapid Symmetricals, being aplanatic, work with full aperture, and are, perhaps, the best and most useful Lenses an Amateur or Professional Photographer can possess for general outdoor purposes. Views 3x3 4*x3i 5x4 6x5 8x5 8-U6i 9x7 10x8 12x10 13x11 15x12 Groups Stero. 4ix3 5x4 7*x4 8x5 8*x6* 9x7 10x8 12xlC 13x11 Focus Sin. 4* in. 6 in. 74 in. 9 in. 10* in. 12 in. 14 in. 16Jin. 18 in. 20 in. Prices 3 10s. 4 4 5s. 5 5s. 5 15s. 6 10s. 7 10s. 8 10s. 10 10s. 11 10s. 14 10s. 3185 UNIFORM RATIO OF STOPS. INTERMEDIATE STOPS SUPPLIED IF REQUIRED. Nos. Ratios . *o 8 1 11-3 2 16 3 / 22-6 4 32 5 ,{, 6 64 *0 signifies the ratio of the Lenses to their foci. Ten per Cent Discount on Ross' Lenses when Remittance accompanies Order. Lenses by any other Makers supplied at their List Prices. 528 NEGRETTI AND ZAMBRA, HOLBORN YIADUCT, E.G. FIG. 3186. FIG. 3186." SLIDING BODY CAMERAS. OF ORDINARY CONSTRUCTION, FOR TAKING PORTRAITS AND VIEWS EITHER ON GLASS OR PAPER, &C. The following Prices are for Cameras only. The price and description of Lenses will be found on pages 517 to 523. s. d. 3186 Square Sliding Body Camera (fig. 3186), of Polished Mahogany, with one single back (fig. 3186*), 5 inches Square, with two loose frames, for pictures 4| by 3 inches, and 3 by 2| inches, and focusing Screen . 1 10 3187 Square Sliding Body Camera, for plates 5 by 4 inches and 4 by 3i inches 1 16 3188 Square Sliding Body Camera, for plates 6 by 5 inches, and 5 by 4 inches ; this size is suited to a single Carte de Yisite or Cabinet size Picture ... 2 10 6 3189 Square Sliding Body Camera, for plates 8i by 6| inches, 6 by 5 inches, and 5 by 4 inches 440 3190 Square Sliding Body Camera, for plates 12 by 10 inches, 10 by 8 inches, and 8.? by 6 inches .... 770 FIG. 3191* 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 529 FIG. 3191. IMPROVED MAHOGANY CAMERAS. WITH PORTABLE BELLOWS BODIES. 3191 These Cameras are made of the very best seasoned Spanish mahogany, finished in the most careful manner, and are capable of adjustment for both Portrait and Landscape Lenses. They are made with parallel bellows, folding base, swing back and double fronts, as shown in fig. 3191. The focus is obtained by means of an endless screw, or rack and pinion movement, according to size. The Price includes a focussing screen, but dark slides are extra, as given in the adjoining columns. Fig. 3191 shews the Camera. Fig. 3191* packed up for travelling. Cameras. Dark Slides. Brass Extension Brass For Plates. Price. Binding Bellows Double. Single. Binding extra. extra. extra. & s. d. S. d. 8. d. s. d. s. d. s. d. 4*by 3i 3 15 18 1 17 6 15 6 040 5 4 450 18 2 6 1 17 6 040 6 4f 4 15 1 1 10 140 120 046 8 6 600 1 2 6 13 1 7 6 146 050 8* 8* 6 15 126 13 1 10 166 050 10 8 750 1 7 6 17 6 1 15 1 10 056 10 10 7 15 176 17 6 1 18 6 1 13 6 056 12 10 880 1 12 6 220 250 1 15 6 066 12 12 990 1 12 6 220 276 1 18 6 066 15 ., 12 10 10 220 2 10 300 2 10 7 15 15 12 220 2 10 3 10 2 17 6 070 18 16 17 10 2 12 6 300 4 10 3 12 080 18 ., 18 20 10 2 12 6 300 500 400 080 24 20 28 3 10 4 10 6 10 5 10 090 24 24 31 3 10 4 10 700 600 090 These can be had with Russia leather bellows at an extra cost of from 1 to 4 according to size. Negretti and Zambra recommend the above Cameras as the best for all general purposes, but any other form can be supplied to order. 2 M 530 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, B.C., FIG. 3192. . 3192 MAHOGANY CAMERAS. SECOND QUALITY. 3192 These Cameras are made with portable bellows bodies and rack adjustments, similar to the preceding, but selected Honduras instead of Spanish mahogany is used, and the Swing Back Arrangement is charged extra, as shown below. Cameras (fig. 3912.) Dark Slides (fig. 3192*.) For Plates. Price. Swing Back extra. Double. Single. s. d. & s. d. 8. d. S. d. H by 3J 2 16 12 15 12 5 4 300 12 16 13 6 6 4f 3 12 6 15 17 6 15 8* 6} 400 18 140 18 8* 84 4 15 18 140 18 10 8 550 100 1 10 150 10 10 600 100 1 10 150 12 10 6 10 150 200 1 15 12 12 7 10 150 200 1 15 FIG. 3193. 45, COENHILL, B.C., AND 122, BEGENT STREET, W., LONDON. 531 3193 Square Trunk Rigid Camera for Operating Room (fig. 3194), Spanish Mahog- any French polished, with long-screw adjustment, enabling the operator to use lenses of different focal lengths ; and for copying, with swinging back, for bringing objects at various distances into correct focus; one single back, inner loose frames, and focusing screen : Framed and Panelled. Brass Bound. Plain. Extra. Extra. Each. Each. No. 1 for plates 12 by 10 in. . . 14 10 440 22 No. 2 18 by 16 in. .. 21 10 880 3 10 FIG. 3194, 3194 Single or Double Backs for Cameras (fig. 3194), for prices, see page 529. 3195 Sliding Body Folding Camera. Best Spanish Mahogany, French polished, with one Single Back, two loose f rames r Focussing Glass, and with vertical Sliding Front for adjustment of foreground and sky (fig. 3195). Plain. Brass Binding, (fig. 3195) (fig. 3195*) Extra. No. 1 for plates 9 by 7 in 6 10 160 No. 2 10 by 8 in . . 7 10 1 15 No. 3 12 by 10 in 10 10 1 15 No. 4 15 by 12 in 12 12 220 FIG. 3195. FIG. 3195*. The above can be had framed and panelled, or with fine screw focussing adjustment, at an additional cost. NEGRETTI AND ZAMBRA, being exclusively engaged as Photographers to the Crystal Palace Company, are enabled from great practical experience to supply such apparatus as will really be of service to a Photographer ; and -as the greater part of the articles enumerated are made under their own immediate superintend- ence, and finished with all the most recent and really serviceable improvements, they will be found to work so as to present the least possible chance of failure. All Photographic Cabinet work intended for use in Tropical Climates should be made of Spanish Mahogany, and clamped with Brass, to insure durability. 2 M 2 NEGRETTI AND ZAMBEA, HOLBORN VIADUCT, E.G., FIG. 3196. IMPROVED TOURISTS' STEREOSCOPIC CAMERAS. Each. s. d. 3196 Negretti and Zambia's Improved Tourists' Binocular Stereoscopic Bellows Body Camera with Screw adjustment to Camera for focussing; three double backs, each, for holding two prepared plates, size 6f by 3^ inches, and one single back, for wet or dry process ; focussing glass; very portable, packing into a Mahogany case ; outside dimensions 8f by 5| inches, with two of Negretti and Zambra's Compound Achromatic Lenses with Waterhouse stops, for Portraits and Views (fig. 3196) 12 12 FIG. 3197.. CARTE DE VISITS CAMERAS. 3197 Negretti and Zambra's Improved Double Lens Carte de Visite Camera, as per fig. 3197, arranged for taking two pictures on one plate 6 in. by 4f in., for Operating Room, of best Spanish mahogany, with Rack adjustment, focussing from front, Rising Front, one single back and focussing glass, with Brass Binding . 5 12 For prices of suitable Lenses for above Cameras, see pages 517 to page 527 according to length of Operating Room. 45, CORNHILL, E.G., AND 122, REGENT STREET, \V., LONDON. Fm. A. FIG. 3198. FIG. c. 3198 Solid Leather Cases and Sling Straps, for Plain, Folding, or Sliding Body Cameras, or for Lenses, (figs. 3198 A B and c) &c., &c., made to order. 3199 The Pocket or Satchel Camera, with Walking-Stick Tripod Stand, for working the Dry Plate Process (fig. 3199) 3200 3201 A Portable Pocket or Satchel Camera, of the best construc- tion, for plates 4^ by 3| inches, with three double backs, port- able Tripod Stand and View lens . . . 880 The above Camera packed in a box with the necessary chemicals for developing dry plates. De- veloping Cups and Dish, Plate Box and Printing Frame 10 10 A Portable Satchel Camera, as above, with three double backs, for plates 5 by 4 inches, portable Tripod Stand and View lens _ 10 10 FIG. 3199. 3203 The above with Chemicals, &c., for developing Dry plates, packed in Box 12 12 3202 3204 A Portable Satchel Camera, for Stereoscopic Pictures, with three double backs, and a pair of Lenses, and a portable Tripod Stand 12 12 The above, with Chemicals, &c., for developing dry plates, packed in Box ... 15 15 3205 Prepared Dry Plates, for use with the Satchel Camera 4 by 3 per dozen 2s. 6d. o 3206 Ditto ditto 5 by 4 . . . 3s. 6d. 4 6 Also see end of Photo Section for various Prepared Plates. 3207 Leather Sling Cases, for either of the above Cameras, can be had at an extra charge of 1 Is., 1 12s. 6d., and 2 2s. 534 NEGRETTI AND ZAMBRA, HOLBOBN VIADUCT, E.G., FIG. 3208. FIG. 3208*. 3208 The Improved Developing Box is constructed for working the Wet or Dry Collodion processes. To amateurs, especially, it offers many advantages over the ordinary Dark Tent, which is weighty and cumbersome. Fig. 3208 shows the box open, ready for use ; Fig. 3208* closed. The sides a a, open up and down, and are kept in their position by two braces of wood inside. The hands enter at the sleeves as shown at ft ft. Fig. 1, and the mask, c, which is of black cloth on a wire frame, is set in the door, on top, under which is a plate of white glass to keep the vapour of the collodion from the eyes, and a sliding door under the glass to shut out the light when the face is withdrawn. The bath is let through the bottom at the left hand corner. The yellow glass window is directly opposite the operator. It is provided with a zinc or other kind of tray, with waste water pipe ; also a cistern, d, of india-rubber, for water. Sufficient room will be found inside for the necessary bottles, and a plate draining box. The size of this box when closed and capable of manipulating a plate 8| by 6^ with freedom is 15 by 13 by 7. Prices according to size and arrangement of fittings, 4 10 to 6 6 3209 Patent Automatic Changing Box. By means of this apparatus a sensitised plate can be transferred from the Plate Box to the Camera with great facility, and without the possibility of its being affected by Light. Price of Box to hold Twelve prepared Plates and Dark Slide. For Plates 5 by 4 in. 6i by 4f in. 7 by 5 in. 4 4 4 10 4 16 1 For Plates 8 by 6 in. .550 10 by 8 in. . 660 12 by 10 in. . 770 Brass Binding above, for Tropical Service from 1. 3210 Leather cases for holding Changing Box and Dark Slide from 1 each extra. 3211 Micro-Photographic Camera, complete with Achromatic Lenses, for reducing pictures, &c. ... .... 10 10 3212 Enlarging, Copying, or Solar Cameras Made to Order. 45, COBNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 535 FlG. 3213. 3213 Improved Portable Dark Tent, for working the Collodion Process in tlie open country (fig. 2213). A good substitute for a dark room has long been a desideratum, and we have much pleasure in submitting the present invention to the notice of photographers generally, as combining all that can be required for the purposes of open-air work enabling them to work with as perfect ease and comfort as in their own laboratory at home. The tent consists of a strong box forming a convenient table, mounted upon a firm tripod stand. The lid of the box is hinged, and thrown back at an angle. At each corner of the lid metal rods are fitted into sockets to extend the covering over the head, having also supports at each side, as shown in the engraving (fig. 3213). In the lid is a yellow glass sliding shutter for admitting light, or if pushed back, fresh air to the interior of the tent when desired. This tent has been in practical use for some time, and is found to answer perfectly and fulfil all requirements. The outside measurement, when packed up, is 31 by 21 by 4 ; weight, with stand and covering, 251bs. Size 31 by 21 by 4 .' 66 26 by 19 by 4 55 Ditto with Water Tank fitted inside, &c., and other improvements 3 8 to 12 12 536 NEGRETTI AND ZAMBRA, HOLBORN YIADTJCT, E.G., FIG. 3223. FIG. 3227. FIG. 3218. Each. s. d. Each. CAMERA STANDS. To insure success in taking either Portraits or Views, it is absolutely essential that the Camera should be perfectly steady. Lightness with freedom from vibration are combined in the stands offered in the following list : 3214 Tripod Stand, with round metal top, and bolt screw. Double legs of Ash for small Camera (fig. 3214). 3215 Tripod Stand, with 4-inch triangular metal top (fig. 3215), with double legs and brass stretchers, bolt screw, and nut, with straps 3216 Ditto ditto very strong, with 6 -inch triangular metal top, with bolt and screw, double legs of Ash, polished and hinged with brass stretchers . 3217 Ditto ditto larger, with 8-inch triangular head for large sized Ca'Jiera, very firm .... 3218 Folding Tripod Stand, light and portable, three legs, as per figs. 3218 and 3218*, of new pattern, suitable for Stereoscopic Cameras. . . . 4-inch head 1 10 3219 Ditto ditto 5-inch head 1 12 6 3220 Ditto ditto 6 -inch head 1 16 3221 Improved Adjusting Tripod Stand, the Legs having a sliding-up and clamp adjustment for height, firm and portable 220 3222 Table Camera Stand, for Operating Boom, with adjustments for raising or depressing the Camera . 2 10 3223 Table Camera Stands, in polished oak, very strong, metal rack adjustment, with handle for raising or depressing Camera, also horizontal and vertical motion to top of stand (fig. 3223) .... 7 10 15 110 160 1 10 1 12 6 45, CORNHTLL, E.G., AND 122, REGENT STREET, W., LONDON. 537 FIG. 3214. FIG. 3224. FlG. 3225. FIG. 3215. HEAD BESTS. Each. S, s. d. Each. s. d 3224 Head Rests, of simple form, with screw to attach to back of chair (fig. 3224) 036 3225 Ditto ditto with adjustments for raising and depress- ing with screw to attach to back of chair (fig. 3225) . 056 3226 Negretti and Zambra's Universal Head Rest, with means of adjustment for every position of the sitter, for attaching to chair 1 10 3227 Universal Head or Body Rest, with heavy iron foot, and brass sliding tube, which enables it to be used either for standing or sitting posture (fig. 3227) Of various sizes for Children or Adults 2 10 0330 440 3228 Portable Stills (fig. 3228). It is found convenient to have at hand the means of obtaining Pure Water. See page 406 for Prices and sizes, &c. FIG 3231. FIG. 3230. FIG. 3228. 538 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., 3229 3230 3231 3232 3233 3234 3235 FIG. 3231. FIG. 3234*. LAMPS FOR DARK ROOM. Bunsen's Gas Burners, for boiling or distilling; Gas Jets, with flexible tube, metal chimney, and gauze wire, for burning without smoke, various forms, see ante, page 403. Lanterns furnished with Coloured Glass Shades, for use in dark room (fig. 3230) Improved form of Photographic Non-Actinic Lamp, where the yellow or ruby glass can be raised or depressed (fig. 3231) Studio Lamp with safety Spirit chamber Patent Lamp for the Magnesium Light LEVELLING STANDS, TRIANGULAR PATTERN. With adjusting screws, for levelling plates with Albumen, and Developing and Fixing Collodion Pictures (figs. 3234) : For plates up to 5 by 5 inches Ditto ditto 7 by 6 Ditto ditto 9 by 7 Ditto ditto 12 by 10 (fig. 3234*) . Filter Supports (fig. 3235), plain form .... FIG. 3235. Each. s. 046 10 6 12 6 330 030 046 056 10 6 026 FIG. 3237J. FIG. 3237-f. FIG. 3237 s FIG. 3237. 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 539 3236 COLLODION BOTTLES POURERS, AND FILTERS. The Collodion Bottles (figs. 3236 to 3237) can be used either for mixing the plain Collodion with the lodiser, or for receiving the turbid portion of Collodion when it has been poured over the plate several times ; from the shape of the bottle, it allows Jill particles to subside at the bottom, and enables the operator, after a short time, to pour away the clear Collodion within a very short distance of the deposit, without disturbing it. 3237 Collodion Bottles or Pourer : (Fig. 3237) Plain 2 oz. 4 oz. Price . ... 2s. 3s. (Fig. 3237*) Graduated 2 oz. 4 oz. Price . ... 3s. 4s. 3237* Cometless Collodion Bottle (fig. 3237f). The tube in the neck of this bottle can be removed and cleaned as frequently as used, and so particles of dry Collodion prevented from being carried on to the plate . .040 3237f Collodion Filters (fig. 3237+) . . . . 5s. 6d. 7 6 10 6 3238 Drop Bottles, Improved, for adding small quantities of Nitrate of Silver Solution to developing or other solutions (see pages 192 and 502). 6 oz. 3s. 6d. 6 oz. 4s. 6d. 3243. Fm. 3246. FIG. 3239. Each. FIG. 3249. Each. s. d. 3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 026 s. d. Developing Glasses, nest of three, for pouring develop- ing solution on to plates (fig. 3239) . , . . 040 Ditto Graduated 056 Hydrometers, for testing the Specific Gravity of Acids, Alcohol, ^Ether, &c (see pages 176 to 195 ) Argentometer, for testing strength of Silver Bath, in case Ditto with glass solution Tube in case (fig. 3243) . Dropping Tubes or Pipettes Dropping Tubes, Graduated . . . .Is. 6d. Glass Graduated Measures, accurately divided into Minims, Drachms, and Ounces ; of either Cylindrical or Conical form, see page 384. Scales and Weights see ante, pp. 396, 405, 406, 408. Filter Rings, or Supports, as on top of fig 3246, very useful for filtering small quantities without a funnel Glass Syringes, for taking up small quanties of Liquids, Glass Spirit Lamps Glass Funnels, Glass Stirring Rods, see pages 381, 390, and 391. Thermometers, Chemical and various, see pages 152 to 175. 006 010 540 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, B.C., 3251 Wedgwood Ware Funnels, ribbed inside, see page 381. 3252 Ebonite Funnels: Capacity . . 2 oz. 4 oz 8 oz. 16 oz. Price . . ls.4d. Is. 9d. 2s. 6d. 4s. 3253 Filter Paper, cut round, in packets of 100 each : Diameter . . 65 in. 7? m. 9| in. Price . . Is. Is. 4d. Is. 6d. 3254 Pneumatic Plate Holder, small, with lever ... 03 3255 Ditto ditto large, with lever (fig. 3255) . 4 3256 Cup Pattern Plate Holder 046 3257 Ditto large size 050 3258 Plate Cleaner, with screw adjustment, for cleaning plates of various sizes (fig. 3258) . . . .056 066 FIG. 3260. FIG. 3261. FIG. 3259. FIG. 3255. COLLODION DIPPING BATHS. 12 in. 2s. 3259 Thermometers for Studio or Operating Room (fig. 3259) 026 050 3260 Ditto ditto Registering (fig. 3260) . ' . . 14 110 3261 Hygrometers (fig. 3261) . . . . . . . 14 110 FIG. 3264. FIG. 3262. 45, COENHILL, E.G., AND 122, EEGENT STREET, W., LONDON. 541 3282 Nitrate of Silver Dipping Baths, of Solid Glass, with Stand and Glass Dipper (fig. 3262) : For Plates 4| by 3iin. . 4 6 For Plates 7f by 4J in. 8 6 5 by 4 in. 6 9 by 7 in. 10 6 6 by 4f in. 7 6 10 by 8 in. 15 6 by 5 in. 7 6 12 by 10 in. . 18 6 Stereoscopic 65 by 3iin. .... 6 6 3263 Water-tight Glass Baths, with Dipper, mounted in Polished Mahogany cases (fig. 3263) :- For Plates 5 by 4 in. . 1 2 6 For Plates 10 by 8 in. 2 2 64 by 4f in. 1 8 6 12 by 10 in. . 2 8 6 84 by 64 in. 1 12 15 by 12 in. . 3 13 9 by 7 in. 1 14 Stereoscopic 6f by 3^ in. 1 5 3264 Negretti and Zambra's Improved Water-tight Glass Baths (fig 3264), with accurately fitted glass cover. The top is hinged, and when the bath is in use it can be turned over, as in figure, and at once be put into its place when the bath is out of use ; a shutter is placed at bottom, lined with yellow glass, so that the bottom of bath can be examined as to its freedom from sediment ; this contrivance will be found of great use in Tropical Climates (screwed and brass bound) : For Plates 5 by 4 in. 64 by 4f in. 9 by 7 in. 10 by 8 in. Stereoscopic Size 6f by 3 1 12 2 3 2 10 3 3 For Plates 7 by 44 in. 11 by 9 in. 12 by 10 in. 15 by 12 in. 2 7 6 3 15 480 4 18 6 1 18 6 3265 Porcelain Dipping Baths : No. I 2 3 4 5 6 7 for Plates 9 Stereoscopic size Bath. Stand. Dipper. Complete. 4 by 3 in. . 2/ /8 /8 3/4 5 by 4 in. . 3/ /10 /ll 4/9 64 by4f in. . 3/6 I/ 1/2 5/8 84 by 64 in. . 4/ 1/6 1/6 7/ 9 by 7 in. . 5-6 1/8 1/8 9/ 10 by 8 in. . 8/ 2/ 1/10 12/ 12 by 10 in. . 11/6 2/6 2/ 15 by 12 in. . 23/ 3/ 3/ 29/ 6f by 3^ in. . 4/ I/' H 6/ ,'3265 Patent Ebonite Baths : Various sizes supplied to order. 542 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., FIG. 3270. FIG. 3266 3266 Porcelain Dishes, with Spoufc for Sensitizing or Albumenizing Paper and for Washing Paper Pictures (figs. 3266 and 3266*) : No. 1 For Paper 5 by 4 in. 2 Stereoscopic 6f by 3$ in. 3 For Paper 8 by 6 in. 4 5 6 7 8 9 10 11 12 13 9 by 7 in. 10 by 8 in. 11 by 9 in. . . . . 12 by 10 in. ... 13 by 11 in. 16 by 12 in. ... 16 by 13 in. ... 19 by 12 in. ... 20 by 16 in. ... 24 by 19 in. ... Porcelain Pans Shallow. 309 Porcelain Pans Deep. 11 1 1 3 1 3 1 6 1 6 1 9 1 9 2 2 6 2 9 3 3 6 4 5 6 6 7 6 7 8 6 9 10 6 15 17 6 1 1 1 5 3267 Dippers, of Fluted Glass, for Collodion Baths, in one piece, allowing the fluid to drain down from the back of the plate : Length 6 inches each . .008 8 . . 10 9 010 Length 11 inches each . .012 ,,13 ..016 16 1 10 3268 Porcelain Dippers, see No. 3265. 3269 Silver Wire Dippers, from 10s. 6d. upwards, according to size and Weight. 3270 Well Porcelain Sensitizing, Developing, or Fixing Dishes. These Dishes are very convenient for sensitizing wet or dry Collodion Plates, or for their subsequent manipulation, a very small quantity of solution being required, (fig. 3270) For Plates 10 by 8 in. 11 by 9 in. 12 by 10 in. 076 090 10 6 For Plates 6f by 3 in. .026 6| by 5 in. . 036 8$by6in. .056 9 by 7 in. .066 3271 Ebonite Trays, of various sizes, supplied to order. 3272 Moulded Glass Dishes (fig. 3266). These dishes are entirely unacted upon by the chemicals employed, and can be used without risk : Each. .026 030 Size, 7i by 3| by 1 in. 6 by 4$ by 1 in. 8 by 6 bylin. 9 by 7 by 1 in. 040 056 Size, 10 by 8 bylin. 11 by 9 by 1 in. 12$ by 10$ by 1 in. Each. 066 076 10 6 45, COENHILL, E.G., AND 122, KEGENT STREET, W., LONDON. 543 ^ 3273 FIG. 3266*. FIG. 3273 Elliott's Syphon Washing Trough, in Porcelain (fig. 3273). Very useful for operators or amateurs, as by the use of it a number of prints may be subjected to the action of a continuous stream of water for any time. When the height of the water reaches the bend of the syphon, the water from the lower part of the pan passes away through the f syphon which is then self-acting as long as the water is allowed to pass into the pan. Price 14s. 6d. 17s. 6d. 1 Is. FIG. 3274. FlG .. 3275. 3274 Plate Boxes (fig. 3275), for holding Glass Plates, in plain, well-seasoned Pine Wood : No. 1 for plates 3 by 2 in. For 12 Plates. s. d. 2 3 4 5 6 7 8 9 10 11 12 13 14 4iby 8* in. 5 by 4 in. 6by 4| in. 6fby 3iin. 6 by 5 in. 7 by 6 in. 8i by 6| in. 7fby4i in. 7iby 4iin. 9 by 7 in. 10 by 8 in. 11 by 9 in. 12 by 10 in. 2 026 032 036 036 3 8 4 4 6 039 039 046 050 060 066 079 3275 Plate Boxes 01 Mahogany, at a small advance on above prices (fig. 3275). 3276 Pine Wood Grooving, for storing Negatives, per foot 8d. 12 Grooves. 24 Grooves. 3277 Plate Draining Racks, folding . . . . 040 050 3278 Ditto ditto large size for 12 by 10 Plates 060 9 24 Plates. a. d. 029 033 036 4 4 4 4 5 4 6 4 6 5 6 7 7 9 50 Plates, s. d. 4 4 6 5 6 6 6 6 6 6 6 7 6 8 6 7 6 7 6 8 6 9 6 10 6 12 6 544 NEGUETTI AND ZAMBRA, HOLBOEN VIADUCT, E.G., 3279 4 by 3| per doz. 5 by 4 6fby 3i Stereo 65 by 4f 7by 4 74 by 5 8by 6 9 by 7 10 by 8 11 by 9 12 by 10 2| by 2 per gross 3|by 2} 4by 3| 5 by 4 62 by 4f 8iby 64 10 by 8 12 by 10 GLASS PLATES. NT PLATE. CRYSTAL POLISHED SHEET. This Glass is recommended with s. d. 2 confidence. It is almost as flat as Patent 40 w 3 Plate, and the same substance. . 3 6 Per doz. Per gross, s. d. s. d. . 4 6 4iby 3i . .10 11 . 4 9 5 by 4 . .16 17 6 . 5 6 61 by 4i . .22 26 . 8 5 6by 4J . .26 28 . 12 7iby 44 . .28 . 15 6 7^by 5 . .30 34 . 21 6 8by 6 . .46 52 . 27 6 9 by 7 . .60 70 10 by 8 .68 78 "1 12 by 10 . . 12 130 JLI SANED. BEST CROWN POLISHED. s. d. Per doz. Per gross, s. d. s. d. . . 2 2* by 2 .04 33 . . 3 6 3iby 2} . .06 53 . . 7 4? by 3 . .10 11 6 . . 11 6 5 by 4 .15 16 6 . . 21 6Jby 4| . .24 25 6 . . 40 8|by 6 . .44 52 . . 64 10 by 8 .90 87 110 12 by 10 . 13 150 3280 FILTERING PAPERS. White Filtering Paper ..... Ditto ditto extra thick, free from iron or other impurities Swedish Filter Paper ......... Papier Joseph ........ Drying Boards, stout, white, 194 by 25 in. . . . per quire Circular Filter Papers, in packets of 100 . . . per ream 6 in., per packet Is, ; 10 in. Is. 6d. ; 13 in. 2s. 6d. Each. s. d. 1 1 4 1 5 3 3 3281 PHOTOGRAPHIC PAPERS. I 'er quire s. d. 3 6 4 12 6 Per ream. s. d. 300 330 10 10 Plain Rive Paper, best quality Plain Saxe Paper, 23 by 18 Prepared Wax Negative Paper NEW SUPER- ALBUM ENIZED, RIVE AND SAXE'S PAPERS (SELECTED). Saxe's Positive Thick 070 660 Ditto ditto Medium . . . . . .070 660 Rive's Medium .066 600 Ditto Thick 066 600 The various Photographic papers of Euglish manufacture supplied to order. See next page, Formstecher's Albumenized Paper. 45, COKNHILL, E.G., AND 122, EEGENT STREET, W., LONDON. 545 FORMSTECHER'S DIAMOND ALBUMENIZED PAPER. JULIUS FORMSTECHER ^ & CHARLES SEIB. TRADE Jf MARK. SCHUTZIVLARKE OFFENBACH-ON-MAINE. NEGRETTI & ZAMBRA, HOLBORN VIADUCT, LONDON", E.G. Sole Agents for Great Britain, the Colonies, China, Japan, and South America. 3282 This Albumenized Paper possesses the advantage of giving prints of extraordinary softness and brilliancy of tone, the photograph being on the surface, and not in the body of the paper, as is the case with the ordinary quality. REDUCED PRICES. 10 Kilo Rose . . .60 per ream. Half Reams at 5 15 per ream, 10 Kilo Yiolet . . . 6 per ream. Ditto 650 Discount, 5 per cent for cash. Sample quire sent on receipt of stamps or P.O.O. for 7s. 6d. DIRECTIONS FOR USE OF FORMSTECHER'S DIAMOND ALBUMENIZED PAPER. The Sensitizing Bath. Nitrate of Silver, 1 ounce, Distilled Water, 10 ounces-. If used stronger it drains unevenly from the paper. Floating should not be less than four minutes for thin, and five minutes for thick paper, otherwise the salting will not be completely converted into Chloride of Silver or the Albumen coagulated ; and if this is not the case, the albumen partially dissolves in the subsequent washing, producing flat and spotty results. Prolonged floating has no injurious effects. The temperature of the bath ought not to be less than 66 Fah. The sensitized paper should not be allowed to curl, or the surface will crack ; it should be kept perfectly flat. The paper will tone with any of the recognised formulae, but the Chloride of Lime is recommended, which may be used a longer time than the ordinary baths, by adding additional gold as required. The prints should be washed in the usual way before toning. The Toning Bath, No. 1. Chloride of Gold, 15 Grains, Distilled Water, 10 drachms. No. 2. Chloride of Lime, half ounce ; water, 40 ounces. Take one ounce of No. 1, the same of No. 2, half a teaspoonful of chalk or whiting, and water 18 ounces ; shake well and let stand three or four days, then filter for use. When the bath is exhausted, add more of No. 1, and a little chalk to neutralize the gold. No. 2 must seldom be added, and then only in small quantities, as an excess is injurious, producing cold grey tones and a bleaching effect. The Fixing Bath. Hyposulphate of Soda, one ounce, and Water, one pint. A weak solution is recommended, the fixing being equally perfect. A stronger solution tends to blistering. It is most important that all the solutions and washing waters should be the same temperature TO"* 1 Fah. Higher or lower temperature is apt to produce blisters, which are better avoided, although of little consequence in the finished picture. One ounce of common salt to one pint of water in the first washing water is a remedy against blistering. 2 N 546 NEGRETTI AND ZAMBEA, HOLBORN VIADUCT, E.G., IMPROVED PRESSURE, REVERSING, OR PRINTING FRAMES. These frames are constructed that a uniform pressure may be obtained, thus insuring perfect contact between the positive paper and negative plate. FIG. 3283. FIG. 3284. 3283 Mahogany Each. 3284 Pressure Frames, with jointed backs for examination whilst Printing, in Oak or French Polished Mahogany, of the best kind and make (fig. 3283) : Oak Each s. No 1 size of glass 9 by 7 in 12 2 10 by 8 in 14 3 11 by 9 in 15 4 12 by 10 in ' 17 6 15 by 12 in 12 Pressure Frames, of Common kind and make, with screws or springs, and hinged backboard and glass (fig. 3284) : Size for pictures, 7 by 6 in. 9 by 7 in. 10 by 8 in. 12 by 10 in. 14 by 12 in. Price . 7s. 6d. 9s. 6d. 13s. 6d. 16s. 6d. 21s. e. 15 16 18 1 1 1 10 3284* Instantaneous Photographic Shutters of different forms, Marshall's Patent Pneumatic arrangement, the Economic Patent, the Phantom Pneumatic, White's Shutter, &c., &c., supplied to order. Prices varying from 21s., 26s., 30s. to 38s. each. A cheap Drop Shutter can be supplied at 12s. 3284f Enlarging Lanterns. Complete Enlarging Lantern, fitted with Paraffin Lamp, 5 Inch Condenser and Achromatic front Lenses, best mounting and finish 10 10 Ditto ditto 7 Inch Condenser 14 14 FIG. 3284J Improved Graphoscopes, for particulars and prices, see page 228. 45, CORNHILL, E.G., AND 122, KEGENT STREET, W., LONDON. 547 3285 Pressure Frames, in "White Wood, Common kind, with hinged backs, without Glass : For plates 4 by 3 in. 5 by 4 in. 6iby4fin. 7* by 4* in. s. d. s. d. r s. d. s. d. 16 26 For plates 8 by 5 in. . 3 46 20 30 8 by 6^ in. . 3 5 46 30 40 9 by 7 in. . 3 6 50 20 46 12 by 10 in. . 5 6 80 Stereoscopic 6f by f in., 4s. A B FIG 3286. c D 3286 Glass Cutting or Shaping Plates, with bevelled and polished edges. These plates are for placing over the positive paper prints before mounting, and are of four patterns Oval, Square, Dome, and Cushion, being held firmly on to the picture. When the best position of the picture is obtained, a sharp-pointed knife is run along the outer polished edge of the shape ; the picture is then ready to be placed on card-board. Glass Cutting or Shaping Plates (figs. A B c D, No. 3286). For Pictures 2 by 2 in. each 006 3iby2fin. 008 4iby3iin. 009 5 by 4 in. 010 For Pictures 6^ by 4f in. each 8 by 6i in. 10 by 8 in. Carte de Yisite , 3287 Cutting Knives, for using with above each 1 3288 Vignette Plates, for Portraits or Landscapes (fig. 3288) : Size Carte de Yisite 6iby 4|in. 8 by 6| in. 9 by 7 in. 10 by 8 in. ,,12 by 10 in. FIG. 3288. Double for Stereoscopic pictures, each 2s. 6d. by 2 in. . each 006 by 2f in. 009 by 3^ in. 010 by 4 in. 016 010 1 10 022 026 3 4 6 2N2 548 NEGRETTI AND ZAMBKA, HOLBOEN VIADUCT, E.G., FIG. 3302. FiG. 3290. FIG. 3300. FIG. 3301, Each. s. d. price 2s. Each. s. d. 10 6 3290 Buckle's Brushes (fig. 3290), for spreading solutions on Paper ; Glass Tube, B, Silver Wire Hook, A, which draws a piece of wool partly through the tube at C, 3290* Glass Rods, for spreading solutions on to paper, 3d., 4d., 6d., Is. 3291 Wood Clips, for suspending sheets of paper to dry, Is. 6d. per dozen. 3292 Glass Clips, 3s. per dozen. 3293 Plate Cleaning Liquid, per bottle Is. 3294 India-Rubber Finger Stalls, 6d. each. 3295 Leathers for cleansing Glass plates, from 2s. ditto. 3296 Double Zinc Dish for Waxing Paper, very convenient . 3297 Horn Forceps, for manipulating with Waxed or other Paper 3298 Boxwood Forceps, for the same purpose 3299 Silver Wire Hooks, for lifting sensitive plates from dishes, from 3300 Ebonite Forceps, without rivets (fig. 3300) 3301 Circular Spirit Level, best make, for accurately level- ling Cameras, or Glass Plates for developing (fig. 3301) 3302 Photographic Visuometer (fig. 3302) for enabling the tourist to judge of the effect of a landscape 3303 Focussing Glass, or Eye-Piece, for obtaining a perfectly sharp picture, see page 227 . . . 5s. 6d. 12 6 16 3334 Magnifying Lenses for examining Photographs, &c., of various sizes and mountings (see pages 221 and 222). 3305 Instrument to count Seconds 3305* Sabine's Photometer, a very useful Instrument for the use of Photographers .. 066 046 1 10 2 10 12 6 3306 PHOTOGRAPHIC BRUSHES. 1 and 2, Small Camel Hair Ditto, No. 3 Sables in Quills Miniature Brushes . Sables in Albata, very fine Camel Hair Dusters Round Camel Hair Brushes in Tin Stumps per dozen each 4d., per dozen 006 040 each each (Jd., each 1 3307 Camel Hair Brushes, for spreading solutions on to paper, made without metal binding : Breadth . 1| in. 2 in. 2} in. 3 in. 4 in. 5 in. Price, each Is. 6d. Is. 9d. 2s. 3d. 2s. 6d. 3s. 6d. 4s. 6d. 3308 Ditto, Thick Round, Is. and Is. 6d. each. 3309 Ditto ditto bound with Silver Wire ... .020 3310 Gold, Silver or Alumina Shells ... 6 6 3 2 6 006 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDOX. /In /*1?5ifck 549 FIG. 3311. FIG. 3312. 3311 Double Geared Rolling Machine, with Fly Wheel (fig. 3311.) Size of plate, 21 by 15 in., 10 10s. ; 24 by 18 in., 14. 3312 Amateur's Rolling Machine (fig. 3312). Size of Plate 9 by 6 in. 350 3313 Hot Rolling Machines with| Lamps and tubes ; Single Geared with Steel Plate 12 in. by 7 in 6 10 18 in. by 13 in 12 12 Ditto ditto Double Geared. 20 in. by 16 in 19 10 24 in. by 18 in . 25 3314 Eureka Burnisher can be heated with any kind of Lamp, Alcohol, Oil, or Gas. Prices 6 in. Roll . .440] Prices 14 in. Roll . .880 10 in. . . 6 6 I 20 in. . 11 3315 Albums for holding Carte de Yisite or Cabinet Sized pictures in a variety of mountings, and of sizes to contain 10, 25, 50, 80, and 100 Pictures ; price, according to number to contain and finish 3316 Backgrounds for the Operating Room, sizes suited for the room painted to order : Size 6 by 4 feet .... Price about 7 by 6 feet 050 550 1 10 2 2 3317 STOPPERED BOTTLES FOR CHEMICALS. Green Glass (narrow mouth). White Glass (narrow mouth), White Glass (wide mouth). 5 oz capacity 5d. 1 oz. 4d. 10 6d. 2 6d. 16 7d. 4 8d. 20 8d. 8 9d. 1 oz. 2 4 5d. 7d. 9d. Is. 3318 NITRATE OF SILVER. These Prices are for Cash only, which must accompany the order, as credit cannot be given. 1 oz. and under 5 ozs per oz. 3s. 6d. 5 oz. 10 ozs 3s. 3d. 10 ozs. 25 ozs 3s. Nitrate of Silver Bath, prepared for Positive or Negative process. inclusive of bottles per pint 3319* Nitrate of Silver Baths, 60 grains to the oz. of Distilled Water for sensitizing albumenized paper .... per pint 11 3319 8 550 NEGBETTI AND ZAMBEA, HOLBOBN VIADUCT, E.G., 3320 Hard Crystal Varnish for Collodion Negatives, in bottles, Is. 6d., 2s. 6d., and 4s. 6d. Per Pint, 7s. DIRECTIONS FOR USE. "Warm the plate gently by the fire, and pour on the Varnish in the same manner as the Collodion, returning the superfluous quantity to the bottle ; then hold the Varnished side to the fire for a few moments ; the Varnish n r ill, when cold, present a perfectly hard and even surface. This Varnish if diluted with Alcohol (strength 62 O. P.) in the proportion of 5 ozs. of Varnish to 3 ozs. of Alcohol, will make an excellent print varnish for preserving Photographs from fading. DIRECTIONS. Pour sufficient of the diluted Varnish into a clean dish, then immerse the print for about two minutes, remove, and when dry it is ready for mounting. A second immersion in the Varnish will give the print a better surface if required. 3320 Liquid Jet, for applying to the back of the Collodion Positives, giving great brilliancy and lustre to the pictures. This preparation is not liable to crack. Price 6d. per 4 ounce bottle ; 8 ounce ditto, Is. COLLODIONS FOR NEGATIVE AND POSITIVE PICTURES. 3321 Thomas's Negative Collodion, with Potassium lodizer, Cadmium lodizer, Bromo-Cadmium lodizer, or Bromo-Potassium lodizer. 1 pint 10s., ^-pint 5s. 3322 Thomas's Positive Collodion and lodizer,, in pints 10s., i-pints 5s., |-pints 3s. 3323 Mawson's Negative and Positive Collodion, i-pints 2s. 9d., i-pints 5s, pints 10s. 3324 Card Mounts, for mounting Stereoscopic Paper pictures, per 100, Is. 6d., 2s. 6d., and 5s. 3325 Enamelled Stereoscopic Card Mounts, per gross . . .066 3326 Card Mounts, stout, for Carte de Visite Pictures, per 1,000, 10s. 6d. 12 6 PURE CHEMICALS AND PREPARATIONS. USED IN THE PHOTOGRAPHIC PROCESSES. s. d. Peroz. 3327 Acid, Acetic, Glacial, Solid at 50 , . per lb., 2s. 003 3328 Citric, Crystals .... per lb., 3s. 004 3329 Formic 006 3330 Gallic 008 3331 Hydrochloric, Pure . . . per lb., 8d. 002 3332 Nitric, sp. gr. T450, pure . ..per lb., Is. 6d. 002 3333 Pyrogallic, pure English 040 3334 ., Succinic .......... 056 3335 Sulphuric . . . * . . . per lb. 003 3336 pure 016 3337 Tannic, pure Soluble ...... 010 3338 Alcohol per pint, 4s. and 5s. 004 3339 Absolute, sp. gr. -796 ,. . 7s. 6d. . 006 45, CORNHILL, E.G., AND 122, KEGENT STREET, W., LONDON. 551 s d. Per oz. 3340 Ammonia, sp. gr. '880 . . .per lb., Is. 6d. 002 3341 Ammonium, Bromide, free from Iodide 3s. 6d. 004 3342 Chloride, pure, free from Iron 2s. . 004 3343 ., Fluoride 009 3344 Iodide, pure 020 3345 Sulphide perlb. 050 3346 Barium, Chloride per lb., Is. 003 3347 Iodide 030 3348 Baryta, Nitrate . . . . . perlb. Is. 6d. 002 3349 Benzole per pint 020 3350 Bromine, pure 026 3351 Cadmium 040 3352 Bromide, pure Crystal 026 3353 Iodide 026 3354 Calcium, Bromide 026 3355 Iodide, pure 030 3356 Charcoal, Animal per lb. Is. 8d. 005 3357 Chloroform ,,10s. 6d. 010 3358 Collodions, various, see previous page 3359 Cotton Wool, Best . . 003 3360 Dextrine per lb., Is. 3d. 002 3361 JEther, Sulphuric, sp. gr. 720 . . 7s. 6d. 004 3362 -750 . . 8s. 6d. 006 3363 JEther, Sulphuric, Methylated Spirit, sp. gr. '720 per lb., 3s. 003 3364 Glycerine, pure distilled ... 4s. 006 3365 Gold Chloride, in 15 gr. tubes | drachm . each 026 30 i ... 046 60 1 ... 086 3366 and Soda, non-deliquescent, neutral, 15 grs. 026 3367 Gun Cotton (Pyroxyline) 026 3368 Paper 040 3369 Iodine, pure (variable) 020 3370 Chloride 056 3371 Iron, Ammonio Citrate per lb. 050 3372 Bromide 030 3373 Iron, Developer perlb. 010 3374 Saccharo Sulphate .... 016 3375 Iodide 016 3376 Proto sulphate .... per lb. 6d. 001 3377 Kaolin (China Clay), Washed . 9d. 001 3378 Lime, Bromide 036 3379 Cylinders, for Oxy-hydrogen Light, see page 363 3380 Lead, Nitrate 003* 3381 Acetate 003 3382 Magnesium Wire . . . . . . per foot 002 3383 Mercury, Distilled per lb., 3s. 6d. 003 3384 Bichloride 006 3385 Naptha, Vegetable per pint 013 3386 Platinum, Bichloride Solution . . .per dram 050 552 NEGRETTI AND ZAMBBA, HOLBORN VIADUCT, E.G., s. d. Per oz. 3387 Potash, Bichromate 006 3388 Chlorate per Ib. 026 3389 Nitrate Is. 001 3390 Potassium, Bromide, pure 010 3391 Cyanide . . . in 1 Ib. bottles, 4s. 004 3393 Fluoride 008 3394 Iodide, pure 016 3395 Plate Cleaning Solution .... per bottle 010 020 3396 Silver, Nitrate, see page 3397 Oxide, pure 090 3399 Soda, Acetate per Ib., Is. 6d. 002 4000 Hyposulphite ... 28 Ibs., 6s. 6d., per Ib. 004 4001 Phosphate ........ 002 4002 Sodium, Chloride, pure , 002 4003 Fluoride 0' 1 6 4004 Sugar of Milk 008 4005 Grape 006 4006 Tannin 010 4007 Test Paper, Blue Litmus, or Red . . . per book 002 4009 Tripoli 004 4010 Rouge, fine . . 006 4011 Rottenstone, prepared ....... 006 4012 Uranium, Nitrate per tube 030 4013 Varnish, Amber, in Chloroform 016 4014 Crystal Varnish . . . per bottle, 4s. 004 4015 Black Jet per bottle 006 010 4016 Sohnee Freres .... 019 4017 Spirit Varnish ...... per pint, 7s. 006 4018 Water, distilled, Chemically pure . . per gallon 008 4019 White Wax, free from Stearine ... per Ib. 040 These prices are subject to frequent variation. All other Chemical Tests and Re- Agents supplied to Special Order. Messrs. Negretti and Zambra in republishing their Catalogue of Cameras, Lenses, and Apparatus med in the Photographic Art, wish to state, that being exclusively Photographers at the Crystal Palace, Sydenham,for over thirty years, they are enabled from their lengthened practical experience to supply such Instruments as will really be found of service to purchasers. The larger portion of the items in the List are made under N. $ Z's. personal superintendence ; and being finished with all the most recent and useful improvements they will be found to work with the least possibility of failure. Photographic Lenses or Apparatus supplied by Negretti and Zambra to customers can be if desired tested by their Operators at the Crystal Palace, and every explanation given as to Photographic Processes and Improvements that may be from time to time introduced. INSTRUCTION IN PHOTOGRAPHY, by CAPTAIN ABNEY, Price 3s. 6d. NEGRETTI & ZAMBRA'S ILLUSTRATED GUIDE TO PHOTOGRAPHY. Austrian Gold Medal, for Photographic Stereoscopic Views on Glass. 45, CORNHILL, E.C., AND 122, REGENT STREET, W., LONDON. 553 ESTIMATES FOR SETS OF PHOTOGRAPHIC APPARATUS. s. 4020 No 1 Set, consisting of portable Bellows Folding Camera for Plates 4 in. by 3 in., with three double backs ; Compound Achromatic Lens, Portable Tripod Stand, and all necessary Chemicals and Apparatus for the Dry Plate Process. Packed in strong wooden case for travelling 10 10 No, 2 Set, similar to No 1 Set, but for plates, 5 in. by 4 in. . . 12 12 No. 3. Set, for plates 64 in. by 4f in 16 16 No. 4 Set, for plates 84 in. by 64 in 25 Leather Sling Cases for carrying Dark Slides and Lens made to order. Estimates for larger Sets furnished on application. 4021 4022 4023 4024 4025 PREPARED DRY PLATES. WRATTEN AND WAINWRIGHT'S 'LONDON" GELATINO-BROMIDE DRY PLATES. SIZE OF PLATES. PRICE PER DOZEN. ORDINARY. INSTANTANEOUS. s. d. 8. d. 4? by 3i 2 6 3 5 4 3 6 4 6 6| 3* 4 9 5 9 64 4f 5 6 6 6 44 6 6 7 6 74 5 7 8 6 8 5 7 6 9 6 84 64 10 6 12 9 , 7 11 13 6 10 , 8 14 18 11 , 9 16 21 6 12 , 10 19 26 6 15 , 12 36 45 Other sizes supplied to order. Kennett's, Swan's, Mawdsley's, and other makers' Dry plates at the advertised prices. PLATE BOXES OF EVERY DESCRIPTION. APPENDIX. WEIGHTS AND MEASURES OF THE BEITISH PHARMACOPEIA, 1867. WEIGHTS. 1 Drachm drm. 1 Pound Ib. . 480-0 Grains Troy . . 5760 60 . 20 . Avoirdupois. 437'5 Grains. 37-343 Grains 16 Ounces or 7,000 Grains. 1 oz. Troy. 1 Ib. 1 Drachm 1 Scruple Minim Fluid Drachm Fluid Ounce pint O . Gallon C MEASURES OF CAPACITY. Min. fl. drm. fl. oz. . O . C 60 Minims. 8 Fluid Drachms. 20 Fluid Ounces. 8 Pints. Seconds Pendulum. MEASURES OF LENGTH. 1 Line = -% Inch 1 Inch = T9-.~ 12 Inches = 1 Foot. 36 Inches = 3 Feet = 1 Yard. Length of Pendulum, vibrating seconds of Mean Time in the latitude of London, in a Vacuum at the level of the sea. 39-1393 inches. RELATION OF MEASURES TO WEIGHTS. 1 Minim is the measure of 0'91 Grains of Water. Fluid Drachm . . . 54'68 Fluid Ounce . 1 Ounce or 437'5 Pint . 1-25 Pounds or 8750*0 Gallon . 10 Pounds or 70,000-0 WEIGHTS AND MEASURES OF THE METRICAL SYSTEM. Milligramme = the thousandth part of one gramme, or O'OOl gramme. Centigramme = the hundredth part of one gramme, or O'Ol gramme. Decigramme = the tenth part of ditto, O'l gramme. Gramme = weight of a Cubic Centimetre of Water at 4 Centigrade TO gramme. Decagramme = ten grammes, lO'O. Hectogramme = one hundred grammes lOO'O. Kilogramme = one thousand grammes lOOO'O. MEASURES OF CAPACITY. 1 Millilitre = 1 cub, centim., or the meas. of 1 Centilitre = 10 ditto ditto, or 1 Decilitre = 100 ditto ditto, or 1 Litre = 1000 ditto ditto, or 1 gramme of water. 10 ditto ditto. 100 ditto ditto. 1000 ditto ditto, 1 kilometre. MEASURES OF LENGTH. 1 Millimetre = the thousandth part of one metre, or O'OOl. 1 Centimetre = the hundredth ditto ditto, or O'Ol metre. 1 Decimetre = the tenth ditto ditto, or O'l. 1 Metre" =the ten-millionth part of a quarter of the meridian of the earth. 45, CORNH1LL, E.G., AND 122, REGENT STREET, W., LONDON. 555 RELATION OF THE WEIGHTS OF THE BRITISH PHARMACOPCEIA TO METRICAL WEIGHTS. 1 Pound = 453-5925 Grammes. 1 Ounce = 28-3495 1 Grain = 0-0648 RELATION OF MEASURES OP CAPACITY OF THE BRITISH PHARMACOPOEIA TO THE METRICAL MEASURES. 1 Gallon = 4-543487 litres. 1 Pint = 0*567936 litres, or 567*936 cubic centimetres. 1 Fluid Ounce . . = 0-028396 litres, or 28-396 1 Fluid Drachm . . = 0-003549 litres, or 3'549 1 Fluid Minim . . = 0-000059 litres, or 0'059 RELATION OF THE METRICAL WEIGHTS TO THE WEIGHTS OF THE BRITISH PHARMACOPOEIA. 1 Milligramme = 0*015432 Grains. 1 Centigramme . . . . = 0-15432 1 Decigramme = 1-5432 1 Gramme , . = 15-432 1 Kilogramme = 2 Ibs. 3 oz., 119'8 grains, or 15432-348 RELATION OF THE METRICAL MEASURES TO THE MEASURES OF THE BRITISH PHARMACOPOEIA. 1 Millimetre = 0-03937 Inches. Centimetre = 0-39371 Decimetre = 3-93708 Metre = .39-37079 or one yard 3'7 inches Cubic Centimetre = 15 '432 grain measures. Litre = 1 pint 15 oz. 2 drachms 11 minims, or 15432-348 grain measures. COMPARATIVE TABLE OF ENGLISH AND FRENCH WEIGHTS AND MEASURES. Grains. 1 Drachm Avoirdupois . . 27'343 1 Pound Troy .... 5760 1 Ounce .... .480 1 Drachm 60 Myriagramme (10,000 grammes), 321f Troy Kilogramme (1000 grammes) 32i oz. Troy or 2-2057 Ibs. Avoirdupois. Kilometre (1000 metres) 1093'63 yards, or 0-62138 miles. Myriametre (10,000 metres) 10936-33 yards, or 6-21382 miles. or 22-057 Ibs. Avoirdupois. 1 English Inch is equal to 25'39954 Millimetres. 30 English Inches = 762 Millimetres on the Barometer Scale. OLD FRENCH LINEAL MEASURE. English Inches. 1 Douzieme, or Point = 0'0074 12 Points = 1 Ligne == 0-0888 12 Lignes = 1 Pouce = 1*065765 12 Pouces = 1 Pied = 12-7892 1 Pied = 324-7 Millimetres. Official Standard Bushel, containing the legal Weight of Aq. Destillata, at 62 F. Barometer at 30 Inches, 80 Ibs. Avoirdupois. ^ Bushel . . 40 Ibs. Avoidupois. I Gill .... 5 ozs. Avoidupois. Peck .... 20 U Gill . . . . 2* January, 1870, ascertained error of Standard Bushel in Grains 83'343. 556 NEGRETTI AND ZAMBEA, HOLBORN VIADUCT, E.G., CARAT. Diamonds and Pearls are weighed by the" Carat, which contains 4 grains ; bnt 5 Diamond grains are only equal to 4 Troy grains ; the ounce Troy containing 150 Diamond Carats. The Imperial Pound Troy, made in the year 1758, is that from which all other weights are obtained ; T V of it is the Troy ounce, V is a penny weight.'and ^ of the pennyweight is a grain, so that 5760 grains is a Pound Troy (12 Troy ounces) and 7000 such grains is a pound Avoirdupois, the grain in each case being identical. WEIGHTS AND MEASURES. 480-0 grains Troy = 1 oz. Troy. I 5760-0 grains Troy = 1 Ib. Troy. 437*5 grains Troy = 1 oz. Avoirdupois. I 7000*0 grains Troy = 1 Ib. Avoirdupois. MEASURES Millimetre = 0-03937 inch. Centimetre = 0-39371 inch. Inch = 2*5399 centimetres. OF LENGTH. Decimetre = 3-93708 inch. Metre == 39-37079 inch. | Foot = 3-0479 decimetres. MEASURES OF SURFACE. Square ifich = 6'4513 square centimetres. | Square foot = 9-2899 square decimetres. MEASURES OF CAPACITY. Cubic centimetre = 0'0610 cubic inch. I Litre, or ) 61-0270 cubic inch. Ditto, ditto = '00176 pint. Cubic Decimetre i or 1-760 pint. Cubic inch = 16-3861 cubic centimetres. I Gallon = 4*5434 litres. Milligramme = 0'0154 grains. Centigramme = 0'1543 grains. Decigramme = 1-5432 grains. Grain = 0-0647 grammes. MEASURES OF WEIGHT. Gramme = 15'4323 grains. Kilogramme = 15432'3488 grains. Troy oz. = 31 '1034 grammes. TABLE FOR REDUCING ENGLISH FEET TO FRENCH METRES, AND FRENCH METRES TO ENGLISH FEET. 1 French Metre = 3-2808992 English Feet. Metres or Feet. English Feet and Decimal Parts. French Metres and Decimal Parts. Metres or Feet. English Feet and Decimal Parts. French Metres and Decimal Parts. 1 3*281 0-305 75 246-067 22-860 5 16-404 1-524 80 262-472 24-383 10 32-809 3-048 85 278-876 25-907 15 49-213 4-572 90 295-281 27-432 20 65-618 6-096 95 311-685 28-956 25 82-022 7-620 100 328-090 30-479 30 98-427 9-144 200 656-180 60-959 35 114-831 10-668 300 984-270 91-438 40 131'236 12-192 400 1312-360 121-918 45 147-640 13-716 500 1640-450 152-397 50 164-045 15-240 600 1968-539 182-877 55 180-449 16-764 700 2296-629 213-356 60 196-854 18-288 800 2624-719 243-835 65 213-258 19-812 900 2952-809 274-315 70 229-663 21-336 1000 3280-899 304-794 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. APPROXIMATE HEIGHT DUE TO BAROMETRIC PRESSURE. 557 Inches. Feet. Inches . Feet. Inches. Feet. 31-0 24-5 6152 17-5 14349 30-9 84 24-0 6691 17-0 15707 5 425 23-5 7242 16-5 16487 30-0 857 23-0 7803 16-0 17292 29-5 1296 22-5 8378 15-5 18122 29-0 1743 22-0 8966 15-0 18979 28-5 2198 21-5 9567 14-5 19865 28-0 2661 21-0 10182 14-0 20783 27-5 3132 20-5 10812 13-5 21734 27-0 3612 20-0 11458 13-0 22720 26-5 4100 19-5 12120 12-5 23746 26-0 4598 19-0 12799 12-0 24813 25-5 5106 18-5 13496 11-6 25700 25-0 5623 18-0 14212 The English Standard of Length is the British Imperial Yard, which is the space in- cluded between two points of a certain Metal Bar when at the temperature of 60 Fahrenheit, or 15'5 Cent. A foot, which is the third part of this yard, is the unit generally employed. A Metre, the French Standard of Length, is equivalent to the ten-millionth part of the Arc of the Meridian, extending from the Equator to the Pole. " The Germans indicate inches by putting two accents after the number ; lines by putting three accents. 27" 3'" 1 85, means 27 inches 3 lines 85 hundredths of a line; more frequently they give the height in lines, and the preceding number bacomes 327"' 85." Kaemtz. LIQUID MEASURES. Cubic Inches. 277-274 34-65925 1-7329625 Imperial Gallon . . . . Pint Ounce Cubic Inch in Air, temp. 62 Fahrenheit, Barometer at 30 inches Ditto ditto in Vacuo, temp. 62 Cubic Foot, in Air, at 62, 62-3206 Ibs. avoirdupois. Litre 61-02525 Decilitre 6*10252 Grains of Dis rilled Water. 70000 or 10 Ibs. 8750 437-5 252-458 252-722 15432- 1543*2 Diameter of a Cylinder containing a Gallon at one inch in depth, 18'78933 inches. A Second of Time is the 86,400th part of a Mean Solar Day of 24 hours, and is used as the unit of Time. A Degree of the Equator is 69-1613 miles, or 365,172 feet. A Degree of the Meridian is 69-046 miles, or 364,565 feet. A League is 3 miles. A Fathom used in Sea Sounding is 2 yards, or 6 feet. A Cable's Length is 120 fathoms, or 240 yards. A Military Pace is 2 feet. The Portuguese Mile is 1-2786 English Miles. The Legua (Spain) 8,000 Vara, or 22,256 feet, or 4'2152 miles. The Swiss Meile is 26.666| Fuss, or 8.548 Yards, or 4'8568 miles. The Mil (Sweden and Norway) 6,000 Famn, or 11,690 Yards, or 6'6423 Miles. 558 NEGEETTI AND ZAMBRA, HOLBORN VIADUCT, E.C., A Russian Verst or Werst is 500 Sachines, or 3,500 English Feet, or 0*6629 Miles. A German or Saxony Post-meile is 24,000 Fuss = 7,432 English yards, or 4*277 Miles. Milan and Venice (New Decimal System of 1803). 1 Miglio = 1000 Metri, or 1,093-63 Yards, or 0-6214 Mile English. Siam. 1 Vouah = 6-306 feet English, and the Roeneng = 2,000 Vouahs, or 12,612 Feet, or 2-3886 Miles English. Argentine Vara, 34-10381 English Inches. A Knot, or Nautical Mile, 6,082 feet. An English Ordinary Mile, 5,280 feet, or 1760 yards. A Geographical Mile, 6,080 feet. 1 Cubic foot of Fresh water weighs 62-425 Ibs. = '557 cwt., or 0*028 of a ton. 1 Cubic foot of Sea water weighs 64'11 Ibs. = -572 cwt., or 0-0286 of a ton. 1 Cubic inch of water weighs 0-03612 Ibs. 1 Cubic foot of water contains 6-24 gallons. 1 Cubic foot contains 1728 Cubic inches. 1 Ton of water contains 35'9 cubic feet or approximately 1 cubic metre. 1 Foot in head gives a pressure of 0'4335 Ib. per square inch. 1 Inch of rain collected by an 8-inch circular gauge, = 29 oz. and 18 grains Weight 12-inch circular gauge, 58 oz. 36 grains. Inches of rainfall multiplied by 2323200 gives cubic feet per square mile. Ditto ditto by 14500000 gives gallons per square mile. Ditto ditto by 3630 gives cubic feet per acre. 1 Inch rainfall is approximately 100 tons 9 cwt. per acre. TABLE SHOWING THE REDUCTION OF GRAMMES INTO GRAINS. TABLE SHOWING THE REDUCTION OF CUBIC CENTIMETRES INTO MINIMS. Grammes. 1 equal to Grains. 15-432 Cubic Centimetres. Minims. 1 equal to 16*896 2 j 30-864 2 33-792 3 46-296 3 50-688 4 67-584 4 61-728 5 84-480 5 j> 77-160 f, 101-576 6 92-592 7 118-272 ?j 8 135-168 7 j> 108024 9 152-064 8 ,, 123-456 10 168-960 9 M 138-883 20 30 337-920 506-880 10 (Decagramme) 154-323 40 675-840 100 (Hectogramme) 1543-234 50 100 844-800 IfiSQ-fiOO 1000 (Kilogramme) 15432-348 1000 = 1 litre, or 1-76 pint 16896-000 The gramme is the French unit of weight. A Troy ounce is equal to 31-103 grammes. An Avoirdupois ounce = 28-356 grammes. A cubic centimetre is the unit of French liquid measure ; 1,000 cubic centimetres being equal to 1 litre, or 1-76 pint = 35 fluid ounces. A cubic centimetre of water measures nearly 17 minims : it weighs 1 gramme, or 15*4 grains. A cubic inch is equal to 16-386 cubic centimetres, a gallon = 4*543 litres. 45, CORNHILL, E.G., AND 122, REGENT STEEET, W., LONDON. 559 HORSE POWER OF STEAM ENGINES. When Steam Engines were first introduced, they were commonly applied to work pumps or mills which had been previously wrought by horses. It was therefore convenient to be able to express the performances of these machines by comparison with animal power, to which miners and others had been accustomed. When an Engine was capable of performing the same amount of work in a given time as any given number of horses, such Engine was said to be of so many horses' power. This term having been long in use, it was retained ; it only being requisite to determine upon some standard by which it could be defined. The performance of a horse of average strength working for eight hours a day was therefore selected as a standard or unit of Steam Engine power. Smeaton estimated the amount of mechanical effect which the animal could produce at 22,916 pounds raised one foot per minute. Desaguliers makes it 27,600 pounds raised through the same height. Messrs. Boulton and Watt caused experiments to be made with the power- ful horses used in London breweries, and from the result of these they assigned 33,000 pounds raised one foot per minute as the value of a horse's power ; this estimate is now generally adopted, and when an Engine is said to be of so many horses' power, it means that when in good working order, and properly managed, it is capable of overcoming a resistance, equivalent to so many times 33,000 pounds raised one foot high per minute. Thus an Engine of 10-horse power should be capable of raising 330,000 pounds one foot per minute. It being explained that one horse power expresses 33,000 pounds raised one foot high per minute. 1,980,000 pounds raised one foot high per hour, it is required to determine the quantity of water which a boiler must evaporate per hour for each horse power of the Engine which it works. The quantity Of water requisite to produce this result by evapora- tion will be found by considering that one cubic inch of water evaporated will produce a mechanical force equivalent to 2.160 pounds raised one foot high. If we divide 1,980,000 by 2,160, it will give the number of cubic inches of water that must be evaporated per hour to produce the mechanical effect expressed by 1 horse power ; the result of this division is 916, which is therefore the number of cubic inches of water per hour whose evaporation is equivalent to one horse power. In actual practice it has been customary for engineers to allow one cubic foot of water per hour for each horse power, a cubic foot being 1,728 cubic inches, or about 11 per cent more than the above estimate. Another authority gives the following : 1 square yard of heating One nominal horse power requires ( 5 gallons of water per hour ) surface. approximately . . , ( 15 pounds of coal . . . V 1 square foot of fire bar ) surface. In practice one pound of coal or coke should evaporate about five pounds of water. The nominal horse power of a cylindrical double or single flued boiler may be found approximately by the following rule : The length multiplied by the diameter, and divided by 5. Water Pressure. Height in feet. 1 5 10 15 20 25 Presure in cwt. per square foot. 55 2-78 5-57 8-36 11-14 13-93 Water Water Water Pressure. Pressure in Pressure. Pressure iu Pressure. Pressure in Height in feet. cwt. per square foot. Height in feet. cwt. per square foot. Height ' in feet. cwt. per square foot. 30 , 16-71 70 . 39- 150 83-6 35 . 195 80 . 44-5 175 97-5 40 . 22-3 90 . 50-1 200 111- 50 . 27-8 100 . 55-7 250 139- 60 . 33-4 125 . 69-6 , 300 167- 1 Atmosphere equals 14-71 Ibs. per square inch or about 15 Ibs. approximately. Ditto ditto 29 22 inches Mercury. Ditto ditto 33-9 feet Water. 560 NEGRETTI AND ZAMBRA, HOLBORN VIADUCT, E.C., HEAT DISENGAGED DURING COMBUSTION. Hydrogen Gas . Marsh Gas Olefiant Gas Oil of Turpentine Olive oil . uEther Coke . . 34462 . 13063 . 11&58 . 10852 . 9860 . 9030 . 7000 Wood, dry Wood, moist Carbonic oxide . Sulphur . Anthracite Charcoal . Coal . 4025 3100 2400 2220 8460 8080 8000 Tallow . . . 8000 Diamond . . . 7770 Absolute Alcohol . 7180 Phosphorus . . 5750 Bisulphide of Carbon 3401 Iron . . . 1576 The experiments of MM. Favre and Silbermann are the most trustworthy, as having been executed with the greatest care. They agree very closely with those of Dulong. Taking as thermal unit the heat necessary to raise the temperature of a pound of water through one degree Centigrade, the above table gives the thermal units in round numbers disengaged by a pound of each of the substances in burning in oxyen. The experiments of Dulong, of Despretz, and of Hess prove that a body in burning always produces the same quantity of heat in reaching the same degree of oxidation, whether it attains this at once or only reaches it after passing through intermediate stages. Thus a given weight of carbon gives out the same amount of heat in burning directly to carbonic acid as if it were first changed into carbonic oxide and then this burnt into carbonic acid. GANOT. Heat of a common fire -1141 ; Wind Furnace White Heat, 3300, is stated as its highest temperature. EXPANSION BY HEAT from 32 to 212 Fahrenheit : Mercury Water . Alcohol Sulphuric Acid 0'0180180 0-0433200, from 39 to 212 Q 1-1100 32 to 174 0-0600 Platinum . Flint Glass Brass 0-0008842 of the length. 0-0008117 0-0018708 , The Expansion or Contraction of Liquids heavier than Water (except Mercury) is about 1 degree (or 5 grains) for every 10 degrees of temperature above or below 60 F., varying slightly with the specific gravity of the liquid. Water boiling at ... Alcohol Mercury boils .... Sulphuric Acid A Saturated solution of Sea salt Sea Water 212 Fahrenheit. 174, variable with its Specific Gravity. 660 Q 590 218 to 226 213-2 variable. Specific Gravity of a Saturated Solution of Sea Salt is 1-208 at 60. Average Specific Gravity of Sea Water is 1'026 to 1-028. Vital Heat, 98'5 Fahrenheit. See also page 161. Heat borne by Delaroche 228 Fah. Highest temperature borne by Sir Joseph Banks and Sir Charles Blagden in a prepared heated chamber 264 Fah. ; notwithstanding the extraordinary degree of heat to which the experimenters were exposed for some considerable period, it is stated that the temperature of their bodies was not perceptibly raised. In some of the modern Turkish Baths Dry Air at a temperature varying from 250 to 300 P Fah. is said to be used for short periods of time. Captain Nares and his companions, in the Polar Expedition of 1875-76, state the lowest Temperature experienced was 62 below Zero of Fahrenheit's scale. See also page 195. Oxygen Gas, solid, at 130 Centigrade and under the pressure of 470 atmospheres. 45, CORNHILL, E.G., AND 122, BEGENT STREET, W., LONDON. Boiling-points under the pressure of an atmosphere. Centigrade. Sulphurous Acid . . . . 10 ..Ether 37 Bisulphide of Carbon ... 48 Bromine 63 Alcohol 78 Distilled Water . . . .100 Laws of Ebullition Centigrade. Turpentine 160 Q Strong Sulphuric Acid . . . 325 Mercury , 350 ,, Sulphur 44? Cadmium 860 Zinc 1042 GANOT. I. The temperature of ebullition, or lolling point, increases with the pressure. II. For a given pressure, boiling commences at a certain temperature, which varies in, different liquids, but which for equal pressures is always the same in the same liquid. III. Whatever be the temperature of the source of heat, as soon as ebullition begins the temperature of the liquid remains stationary. Thus, the boiling point of water under the ordinary atmospheric pressure being 212 F. or 100 Gen., it would not be heated beyond that point, whatever the intensity of the source of heat ; the only effect of higher temperature being to hasten the rapidity of vaporisation ; hence all the heat which passes from the source into the liquid is absorbed by the vapour disengaged. SOLIDIFICATION OF OXYGEN. At the Royal Institution, May 27th, 1886, Professor Darwar exhibited for the first time to a few friends, including the president of the Royal Society, the method he employs for the production of Solid Oxygen. The successful device employed by the Professor at the Royal Institution depends upon allowing liquid oxygen to expand into a partial vacuum, when the enormous absorption of heat which accompanies the expansion results in the production of the solid substance. Oxygen in this condition resembles snow in appear- ance, and has a temperature about 200 Centigrade below the freezing-point of water. A supply of this material will enable chemists to approach the absolute zero of temperature and to investigate many interesting changes in the physical properties of bodies under the primordial condition of the temperature of space. INSTRUCTIONS FOR FIXING OR SETTING HORIZONTAL SUN DIALS. It is most important that the plane upon which the Dial is to be fixed be truly horizontal, and the North and South line be accurately ascertained. The surface of the Dial may easily be made parallel to the horizon or level, with the aid of a good Spirit Level, by testing its surface in at least three directions across its diameter. To find the true Geographical North and South or Meridian line for the place, it is requisite to have a good Mariner's Compass, and also to know the Variation of the Compass Needle for the locality at which the Dial is to be erected. For London the present variation is Westerly 18 20' at Kew, 18 Greenwich. Now by the Compass bearings carefully mark off on the plane surface the true North and South points, and by them set the Sun Dial to correspond. This will then indicate Solar or True Time, which agrees with Mean Time (or that shown by a clock) only on four different days in the year. To find the mean time it is necessary to apply a correction called the Equation of J Time, from a table which is mostly engraved upon the best constructed Sun Dials, or upon the wooden Artificial Horizon of Terrestrial Globes. Also see below. A convenient season for setting Sun Dials by this method is about the time of the Vernal or Autumnal Equinox (March and September) when the Dial and clock very nearly agree. COMPASS VARIATIONS. From " Mechanics' Magazine? March I6tk, 1865. See p. 318. Years. Degrees. Minutes. Yearly Bate of Change. Min. 1576 11 15 E . .7 1622 6 15 E . . .11 1(557 True North . 12 1672 2 30 W . . .13 1720 13 W . . .9 1765 20 W . . .5 1819 24 41 W Max. W . 1852 22 18 W . . .4 1865 20 38 W . . .7 2o JffEGRETTI AND ZAMBEA, HOLBOKN VIADUCT, E.G., EQUATION TABLE. JAN. FEBT. MARCH. APBIL. MAY. JUNE. JULY. Ana. SEPT. OCT. NOV. DEC. M 1 Fa st 4 IFast 14 IFast 13 3 Fast 3 1 Slow 34 Slow 24 Fast 4 10 FastS 4 Slow 1 SSlowll 15Slowl5 2SlowlO 3 5 21 13 3 12 7 2 9 1 10 5 15 4 7 2. 7 12 20 14 5 9 6 6 '27 12 7 11 11 1 14 21 6 20 3 10 3 10 1324 13 7 8 8 7 11 10 15 20Fast 1 24 2 13 4 14 1127 12 9 7 10 8 15 9 20Slowl 24 2 27 1 16 5 19 15 29 11 11 6 13 9 18 8 24 2 29 3 31 18 6 27 16 13 5 16 10 21 7 21 7 15 4 19 11 25 6 24 8 17 3 22 12 28 5 27 9 19 2 27 13 31 4 30 10 21 1 24 26Fast 1 28 2 30 3 Fast means that the Clock should be faster than the Dial ; Slow, slower. For Fractional differences of Time consult the Nautical Almanack. Table of the height in feet of tlie rise of SPEING TIDES in various parts of the World. Ft. Ft. Ft. Ft. Abbey Head, England 23 Corunna, Spain . 15 Heligoland , 9i Bamsgate . 15 Aberdeen, Scotland . 12 Charlestown, U.S. 6 Hons* Kong 4f .Rio Janeiro 4 Adelaide, Australia . 6 ISf Jersey, Chan. Islands 30i Ryde Bay . 22 Aden Bav, Arabia 7 Dungeness . 21f St. John.Bay of Fundy 27 Sheerness . 16 Agnes Ft., Scilly Isles 16 Dieppe 27 Lowestoft . 61 Swansea.Mumb esL ;. 27 Air Point, E.D., Eng. 25 Demerara, Guiana 9 Lundy Island, Bristol St. Malo . 25 Akyab, Bay of Bengal 9 Eddystone Light 18 Channel . 27 3an Francisco 4f Algoa Bay, Africa 6i Fleet wood. 26| Margate 154 Sierra Leone ,8 Beachy Head 20 Flatholm Islands 37 Malaga, Spain . 3 Sarawak, Borneo 16| BridgewaterBar.EngJ 35 Folkestone 20 Melbourne, Australia 3 Singapore . 10 Bergen, Norway 4 Foreland, N. . 10 Maulmain, Bengal . 22 Shanghai . 10 Bombay . . . 12-17 Foreland, S. 18 Needles Point . 7* Sydney 4| Boulogne . 25 Formby Point . 28 New York, U.S. 5 Trinidad . 4 Boston, U.S. . 1H Gravesend, Thames m Nelson, N.Z. . 14 Table Bay . 5 Caermarthen, "Wales. 26 St. Katherine Dock 24 Philadelphia, U.S. . 6| Woolwich . 18 Chatham . m Carribbee Islands H Port Philip, Australia 4 Yokohama . 6* Cape Clear, Ireland . 9 Harwich . m Port Eoyal, Jamaica 1 Zanzibar . 10 Calais .... 19 Hastings . 24 TABLE OF DIFFERENCE OF TIME BETWEEN GREENWICH AND THE FOLLOWING PLACES. Time Faster. Time Faster. Time Slower. East of Greenwich. H. M. S. East of Greenwich. H. M. S. West of Greenwich. H. M. S. Algiers . . 12 16 Paris 10 Gibraltar . 21 28 Alexandria . 1 59 32 Pekin 7 46 Havana 5 29 25 Athens (Greece) 1 35 Rome 50 Jamaica, Kingston 574 Berlin . . 53 35 Rotterdam . 18 Lima . 5 8 24 Bombay . . 4 52 Singapore . 6 56 Liverpool . 12 Brindiai (Italy) . 1 12 Siam . 6 40 Lisbon 3*> 86 Brussels . . 19 Suez . 2 10 16 Madrid 14 Calcutta . . 5 54 Smyrna 1 49 Monte Video 3 45 Canton . . 7 33 St. Petersburg . 2 1 16 Mexico . . > 6 3620 Cairo . . 2 5 12 Venice 57 4 New Orleans 600 Cape of Good Hope 1 14 Vienna , 1 5 30 New York, Sandy Christiana . 43 Warsaw 1 24 9 Hook . 4 55 Constantinople . 1 56 Panama . 5 18 Genoa . 35 32 Time Slower. Philadelphia 5 34 Geneva . . 24 37 West of Greenwich . H. M. S. Quebec 4 44 49 Greenwich 12 o'clock" Baltimore . 5 6 27 Rio Janeiro 2 56 36 noon . . 1) Barbadoes . 3 50 28 Savannah . 5 24 21 Jeddo . . 9 20 Boston 4 44 14 Salt Lake City . 7 28 24 Madras . . 5 22 Buenos Ay res 3 53 28 San Francisco . 8 9 47 Manilla . . 848 Cape Horn 4 19 4 Sydney 10 16 Malta . . 58 Chicago 5 50 31 St. Thomas 4 19 41 Moscow . . 2 30 Cincinnati . 5 37 58 Toronto 5 17 34 Munich . " . ' 46 30 Dublin 25 Valparaiso. 4 47 Naples . . 57 4 Glasgow 17 Vera Cruz . 6 24 34 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 563 VELOCITY OF LIGHT. In 1675 and 1676 Olaf Eoemer, a Danish astronomer, first determined the velocity of Light from observations of the eclipses of Jupiter's first satellite as 192,500 miles per second Bradley, at Kew, in 1723 determined the velocity of L'ght as 191,515 miles per second. M. Foucault, by a modification of Wheatstone's revolving mirror, calculated the velocity at 185,177 miles per second. M. Fizeau, at Paris, in 1849, by experiments carried on between Suresnes and Montmartre, found the velocity to be 194,677 miles per second. More recent experiments by Foucault and Fizeau, 186,633 miles per second is stated. By another experiment, the result is given as 196,000 miles per second. The recent American determinations of the velocity of light, justly considered as of far superior precision to any others yet executed, give the following results : Michelson at Naval Academy, in 1879 299,910 km. Michelson, at Cleveland, 1882 299,853 Newcombe, at Washington, 1882, using only results supposed to be nearly free from constant errors 299,860 Newcomb, including all determinations 299,810 To these are added for comparison : Foucault, at Paris, in 1862 298,000 Cornu, at Paris, in 1874 298,500 Cornu, at Paris, in 1878 300,400 The same discussed by Listing 299,990 Young and Forbes, 1880-81 . 301,382 Prof. Newcomb's finally-concluded result is that light travels in vacua at the rate of 299,860 - 30 kilometres per second. And the probable error of thirty kilometres, small as it is, has been liberally estimated. Measures of the Velocity of Light made during the years 1881, 82, ly Professor 8. Newcomb, U.S. Navy. See "Nature," June 21th, 1886. VELOCITY OF SOUND. The velocity of Sound is 1,125' feet in a second, at a temperature of 61 Fahreheit, or 16'6 C ; therefore a distance of 50 miles would be traversed in 4 minutes. In 1823, on two hills, Kooltjesberg and Zevenboomen, near Amsterdam, accurate experiments were made to determine the velocity of sound by Moll and Van Beck. Making corrections for temperature, moisture, barometric pressure, and the action of the wind, the result of these experiments as corrected by Schroder Van der Kolk gives 1,092-78 feet as the velocity of sound per second in a dry atmosphere with the barometer reading 760 m.m., or 29-931 inches. The velocity of sound increases with increase of temperature : this amounts to nearly two feet for every degree Centigrade. For the same temperature it is independent of the density of the air, and therefore of the pressure. VELOCITY OF ELECTRICITY. " This is so great that the most rapid motion that can be produced by art appears to be actual rest when compared with it. A wheel revolving with a rapidity sufficient to render the spokes invisible, when illuminated by a flash of electricity, is seen for an instant with all its spokes distinct as if it were in a state of absolute repose ; because, however rapid the rotation may be, the light has come and already ceased before the wheel has had time to turn through a sensible space. " Let a circular piece of pasteboard be divided into three sections ; let one be painted Hue another yellow, and a third red. Cause it to rotate rapidly, it will appear white, because a sunbeam consists of a mixture of these colours, and the rapidity of the motion causes the distinction of colours to be lost to the eye ; but the instant the pasteboard is illuminated by the electric spark, it seems to stand still, and each colour appears as distinct as if the disc were at rest. 2o2 564 NEGEETTI AND ZAMBEA, HOLBOEN YIADUCT, E.G., " By a beautiful application of this principle, Wheatstone contrived an apparatus by which he demonstrated that the light of the electric discharge does not last the one-millionth part of a second of time. His plan was to view the image of a spark reflected from a plane mirror, which, by means of a train of wheels, was kept in rapid rotation on a horizontal axis. The number of revolutions performed by the mirror was ascertained to be 800 in a second, during which time the image of a stationary point would describe 1,600 circles, because from the laws of reflection the image of an object in a revolving mirror has twice the angular velocity of the latter, and the elongation of the spark through half a degree would indicate that it existSy-g-J^oth part of a second. A jar was discharged through a copper wire half a mile in length, interrupted both in the middle and also at its two extremities, so as to give three distinct sparks. The deviation of half a degree between the two extreme sparks would indicate a velocity of 567,000 miles in a second. This estimated velocity is on the supposition that the electricity passes from one end of the wire to the other ; it however, according to the two fluid theory, the two electricities travel simultaneously from the two ends of the wire, the two external sparks will keep their relative positions, the middle one alone being deflected, and the velocity measured will be only one-half that in the former case, viz., 288,000 miles in a second." There are, however, great discrepancies in the different measurements which have been recorded of the velocity of Electricity, thus : Walker (America) with Telegraph Iron wire makes it 18,780 miles per second. O'Mitchell (America) 28,524 Fizeau and Gonnelle, Copper Wire, make it . . 112,680 Iron Wire . . 62,600 * Astronomers of Greenwich and Brussels, Copper, ) 700 London and Brussels telegraph, make it . ) ' Astronomers of Greenwich and Edinburgh, Copper, I ,- /.^ London and Edinburgh telegraph, make it . j * , NOAD. LAWS OF FALLING BODIES. "The Velocity which is communicated to a "body falling freely by Gravity. Bodies falling freely near the earth's surface, have communicated to them equal additions of velocity in equal times ; and since, by the first law of motion, none of these increments of the velocity are lost, but all accumulated in the falling body, it follows that its actual amount at any time must be proportioned to the time during which the body has fallen. If, for instance, a body has fallen through ten seconds, since in each second the attraction of the earth wil 1 have communicated to it the same addition of velocity, and since all these additions of velocity will be retained in it, its actual velocity must be ten times that which it would have had after falling one second. " The velocity which gravity thus communicates to a falling body in each second of time near the earth's surface is 32 feet, so that after falling five seconds, its velocity will be five times this amount ; after ten seconds ten times this amount ; and so on. The velocity is so great, that it would never have been possible to ascertain its amount by direct observations on the fall of heavy bodies. " Could we, however, by any contrivance, neutralise the gravitating tendency of a body to any known amount ; reduce it, for instance, to one-half or one-tenth or one-hundredth of what it was ; since we should diminish the velocity communicated to it in each second pre- cisely to the same amount, we might thus render its motions so slow that they might be observed and measured, we might thus find the amount of the additional velocity actually communicated to it in each second, and this multiplied by the known number of times by which we had previously diminished the force of its gravity, would give us the velocity which that fall would communicate in each second when undiminislied . This is the object of Attmood's Machine:' (Page 492) Illustrations of Mechanics, Moseley. * Athenceum, January 14th, 1854, 45, COENHILL, E.G., AND 122, EEGENT STREET, W., LONDON. 565 OHM'S LAW. Ohm assumed the passage of the electric fluid from one section to another of the connecting wire to be due solely to the difference of electric tension between the two sections ; he further assumed the quantity of electricity transmitted to be proportional to this difference of tension, and from these fundamental assumptions he deduced the laws of the voltaic circuit. These laws may be briefly stated thus : a. The strength of the current is directly proportional to the electromotive force. I. The strength of the current is inversely proportional to the resistance. c. If the wire which unites the two poles of battery be of the same material, and of the same thickness throughout, the " electric fall " is the same throughout the wire. d. If the wire be of the same material but of different thicknesses, the " fall " is steeper on the thin wire than on the thick. The ' fall " is inversely proportional to the cross section of the wire. e. If the poles be connected by two wires of the same thickness but of different resisting powers, the "electric fall " is steeper on the more resisting wire. The "fall" is directly proportional to the specific resistances of the wires.* It has been found that when the same current is passed respectively through a short and through a long wire of the same material, its action on the magnetic needle is less in the latter case than in the former. Ohm accordingly supposed that in the latter case there was a greater resistance to the passage of the current than in the former ; and he proved that the resistance is inversely proportional to the intensity of the current. On these principles Ohm founded the celebrated law which bears his name, that The intensity of the current is equal to the electromotive force divided by the resistance. "Ci Which is expressed by the simple formula I= R Where I is the intensity of the current, E the electromotive force, and R the resistance.! ELECTRIC UNITS. The Unit of Resistance is 1 Ohm == 1 British Association Unit = 1 B. A. U. = 10 Million Units of resistance, or : 1 Siemen's Unit = 1 S.';E., the resistance of a prism of mercury, 1 metre long, and 1 square millimetre in section at C. 1 Ohm = 1-070 S.E. 1 S.E. = -935 Ohm. 1 Megohms = 1 million Ohms. The Unit of Tension is == 1 Volt = 100,000 Units of Tension. The Unit of Quantity = 1 Weber. The Unit of Charge is = 1 Microfarad = 1 Millionth part of a Farad.f t Electric Testing of Telegravh Cables. By Capt. V. Hoskisev-, Eoyal Danish Engineers. 1 Ohm = about one mile of Copper Wire, No. 16 B. W. Gauge; or 1 mile of No. 8 Iron Wire, B. W. Gauge a rough definition by a Workman. The laws of the voltaic circuit as enunciated by Ohm have been verified by Kohlrausch and others, and found to be in strict accordance with his theory. THERMOMETER SCALES. The Zero or Freezing Point of the Centigrade and of Reaumur's Scale correspond to 32o of Fahrenheit's Thermometer. The Boiling Point of the Centigrade Scale is 100 of Reaumur's Scale, 80 being equivalent to 212 of Fahrenheit. EASY RULES FOE THE CONVEKSION OF SCALES. To convert Fahrenheit degrees into Centigrade, substract 32, multiply by 5, and divide by 9. * See Tyndall's Notes on Electricity. t See Ganot's Elementary Treatise on Physics. 566 45, CORNHILL, E.G., AND 122, BEGENT STEEET, W., LONDON. To convert Centigrade into Fahrenheit, multiply by 9, divide the product by 5, and add 32. To convert Reaumur degrees into Centigrade, multiply by 5 and divide by 4. To convert Reaumur degrees into Fahrenheit, multiply by 9, divide by 4, and add 32. THERMOMETER TABLE. Comparison of Centigrade and Fahrenlmt. Cent. Fah. Cent. Fah. Cent. Fah. Cent. Fah. Cent. Fah. -17.7... 7 ... 44-6 31 ... 87-8 55 ... 131 78 ... 172-4 16 ... 3-2 8 ... 46-4 32 ... 89-6 56 ... 132-8 79 ... 174-2 15 ... 5 9 ... 48*2 33 ... 91-4 57 ... 134-6 80 ... 176 -14 ... 6-8 10 ... 50 34 ... 93-2 58 ... 136-4 81 ...177-8 -13 ... 8'6 11 ... 51-8 35 ... 95 59 ... 138-2 82 ... 179-6 -12 ... 10-4 12 ... 536 36 ... 96-8 60 ... 140 83 ... 181-4 11 ... 12-2 13 ... 55-4 37 ... 98-6 61 ... 141-8 84 ... 183-2 -10 ... 14 14 ... 57-2 38 ... 100-4 62 ... 143-6 85 ... 185 9 ... 15-8 15 ... 59 39 ... 102-2 63 ... 145-4 86 ... 186-8 - 8 ... 17.6 16 ... 60-8 40 ... 104 64 ... 147-2 87 ... 188-6 - 7 ... ]9-4 17 ... 62-6 41 ... 105-8 65 ... 149 88 ... 190-4 6 ... 21.2 18 ... 64-4 42 ... 107-6 66 ... 150-8 89 ... 192-2 5 ... 23 19 ... 66-2 43 ... 109-4 67 ... 152-6 90 ... 194 - 4 ... 24-8 20 ... 68 44 ... 111-2 68 ... 154-4 91 ... 195-8 - 3 ... 26-6 21 ... 69-8 45 ... 113 69 ... 156-2 92 ... 197-6 2 ... 28-4 22 ... 71-6 46 ... 114-8 70 ... 158 93 ... 199-4 - 1 ... 30-2 23 ... 73-4 47 ... 116-6 71 ... 159-8 .94 ... 201-2 ... 32 24 ... 75-2 48 ... 118-4 72 ... 161-6 95 ... 203 1 ... 33-8 25 ... 77 49 ... 120-2 73 ... 163-4 96 ... 204-8 2 ... 35-6 26 ... 78-8 50 ... 122 74 ... 165-2 97 ... 206-6 3 ... 37-4 27 ... 80-6 51 ... 123-8 75 ... 167 98 ... 208-4 4 ... 39-2 28 ... 82-4 52 ... 125-6 76 ... 168-8 99 ... 210-2 5 ... 41 29 ... 84-2 53 ... 127-4 77 ... 170-6 100 ... 212 6 ... 42-8 30 ... 86 54 ... 129-2 TABLE OF MEAN WINTER, MEAN SUMMER, AND ANNUAL MEAN TEMPERATURE FAHRENHEIT. Winter Sum. Annual Winter Sum. Annual Mean Mean Mean Mean Mean Mean Tempt. Tempt. Tempt. Tempt. Tempt. Tempt. London . . 39-5 63 51 Batavia . 79 81 80-5 Dublin . . 40 66-5 49 Madras . 76-5 86 82 Edinburgh 38-5 58- 47-5 Rio Janeiro 68-5 79 73-5 Paris . 38 64-5 51-5 St. Croix (Teneriffe) 64-5 77 71-5 Rome . 46-5 73- 60 Monte Video . 57-5 77-5 67 Naples . 50 75-5 62 Buenos Ayres . 52-5 73 62-5 Gibraltar . 57 73 64-5 Mexico 55-5 66-5 62 Berlin . 30 63 47-5 Algiers . 54- 74-5 64 Stockholm 26 61 42 Nangasaki 47-1 81-8 64-9 Warsaw . . 27-5 63-5 45*5 Cape of Good Hope 58-5 74 66-5 New Archangel . 33 55 44-5 New Orleans . 53 80 67 Constantinople . 40-5 73-5 57 Montreal . 17-5 69 44 Madrid . 42 74 58 Toronto . 26-5 63-8 44-4 Cairo 58-5 84-5 72-5 Penzance 44 62 52 Calcutta . 6f-5 83-5 78-5 Pekin 26 83 55 Bombay . . 74 83 79 Quito 60 60 60 Singapore . 78-5 81 80-5 Canton 55 82 70 PEOFESSOK DANIELS. INDEX The figures in this Index refer to the numbers on the margin of each page of the Catalogue, unless the page be indicated. Abney's Altimeter, 1203. Acetometer, or Acetimeter, 476. Achromatic Condenser, 943. Gillet's, 944. Lenses, Photographic, pages 517 to 527. Microscopes, pages 256 to 275. Object Lenses for Microscopes, page 268. for Telescopes, 871. Stereoscopes, page 231. ,, Telescopes, pages 242 to 255. Acidometer, 475. Baume's, 422. Acoustic Instruments, page 494. Figures, Chladdi's, 3064. Actinometer, Herschell's, 69. Marie Davy's, 72. Adapters, 1889 to 1891. Addiscombe Set of Drawing" Instruments, 1478, 1478*. Adhesion Plates, 3027. Admiralty Charts, page 327. Agricultural Barometer, page 144. Agricultural Test Chests, 2371. Air Gun, 2906. Tubes, page 375. Air Jars, page 375. Covers, glass, 2002. iAir Pump Receivers, page 476. Air Pump, Davenport's, 2835. Newman's, 2841. Smeaton's, 2841. Tate's, 2847, 2848. Sprengel's, 2849. Triple Cylinder, 2832. Vacuum and Pressure Gauge, page 207. for Diving Apparatus, page 505. Air Pumps, double barrel, page 469. single, 470. Air Meter, page 99, 100. [101 to 103. Colliery (Lowne's Patent), page Air Thermometer, Boyle's or Santorio's, 360, 2951. Air Shaft Thermometers, Registering, 371. Airy's Altitude Tables, page 133. Aitken's Clinical Thermometers, page 160. Alarm Thermometers, 357, 358. Electrical, page 460 to 465. Albumen Views and Statues for the Lantern, page 369. Albumenized Papers, pages 544, 545. Albums, 3315. Alcoholmeter, Field's Patent, page 193. Alcoholmeter, Gay Lussac's, 499. ,, Tralle's Normal, 504. Alcoholic Wine Tests, page 193. Alphabetical Telegraphs, 466. Alembics, 1908 to 1910. Alkalimeters, 1902 to 1906. Mohr's, 2278. Schuster's, 1906. Almanacs, Nautical, page 327. Alpine Aneroids, page 25. Thermometers, 71. Altimeter, 1203. Altitude Measurements by the Barometer, pages 10, 12, and 26. Altitude and Azimuth Instrument, 1107 to 1112. Altitude Aneroid Barometers, pages 23 to 25. Altitude, Quadrants of, 1452. Aluminium Field and Opera Glasses, pages 234 to 240. Telescopes, 830. Weights, 2353. Amalgamated Zinc Battery Plates, 2582. Amalgam, Electrical, 2505. American Hand Level, 1147. Ampere's Apparatus. 2684. Amplitude Compasses, 1377. Analysis of Soils, &c., apparatus for, 2371. Analyser, Spirit, Long's Patent, page 193. Analytical Weights, pages 400, 408. Anatomical Preparations, 1034. 68 KEGBETTI AND ZAMBEA, HOLBOEN YIADTJCT, E.C. Anchor Lamps, pages 322, 223. Anemometer, Land's, 138. Registering, 139. New Self-Timing, 143. Biram's, 142. Negretti and Zambra's Improved Robinson's/self-recording, 105, 106. Osier's Self-Registering,pagel07. Robinson's, page 104. Whewell's, 148. Beckley's, 150, page 109. Negretti and Zambra's, 151. Pendulum, Negretti & Zambra's Improved Prestel's, 137. Electro-Magnetic Recording, Wheatstone's and Crossley's, page 111. Pocket, 140, 142, 143. Anemograph, pages 107 to 110. Anemometer Counting Machine, 2827. Anemometer Tables, pages 97, 99, 103. Anemoscope, Halleur's, 135. Aneroid Barometers, pages 21 to 29. described, page 21. ,, in Ornamental Mountings, pages 1 50, 151. in ditto for Boats, Yachts, and Ships, page 149. Engineers', Surveyors', or Mining, page 295, 296. Mountain or Alpine, page 25. Recording, pages 27, 28. Angles, for drawing, various, 16, 27. Animalculae Cage, 986. Tubes, 999. Annular Micrometer, page 255. Anorthoscope, Wheatstone's, 754. Anvils, Miueralogical, 2025. Automatic Counting Machines, pages 200, 201, 467. Aphengoscope, 1774 Apparatus, Chemical, page 375. Apparatus, Bain's Sounding, 2682. Berzelius', 2129. Biot's, 1052. Blowpipe, for pocket, 2167*. Brooke's, 3063. Cavendish's, 2131. Clark's Arsenic, 2141. ,, for showing conducting power of various Metals, &c., 2971. conducting power of Water, 2987. ,, Convection, 2289. ,, Diving, pages 505, 506. Apparatus, Dobereiner's, 2133. ,, Donovan's, for filtering Caustic Potash, 2132. Dr. Ure's Steam, 2947. Dr. Wollaston's Steam, 2953. Arago's, 2694. 'Hittorf's Electric Spark, 21. Electrotype, page 440 to 442. , , for Electrolysis of Water, page 435. Mariotte's, 2907, 2908. Faraday's, for decomposition, 2536. for testing the illuminating power of Coal, Gas, .Photometers, &c , page 497. for determining altitude, page 92. for Dissolving Views, pages 358 to 361. &c., for Microscopes, pages 269 to 275. ,, for experiments with Ruhmkorff's Coil, pages 451 to 454. for experiments with Steam and Heat, page 481. ,, Faraday's, for exhibiting rotating wire,' 2689. for experiments of centre of gra- vity, or Buoyancy, 2934, 3031. ,, for experiments with Heat, pages 481 to 488. for explaining Mechanical Powers, page 491. for firing Gunpowder, &c., 2573. Flint and Steel, 2896. for Ghost Effect, see Lantern Manual. ., for illustrating composition of water Synthetically, 2128. for illustrating decomposition of water, 2560 to 2565. for illustrating recomposition of water, Cavendish's, 2131. for illustrating laws of falling bodies, page 492. ,, for illustrating laws of Spouting Fluids, 2932. for illustrating parallelogram of forces, 3033. ,, for illustrating mechanical properties of air, 2888. ,, for illustrating pressure of air, 2893. for illustrating the centre of Buoy- ancy, Meta-Centre, &c., in Ship- building, 2934 and 3031. ,, for making gold size cells, 1006. for making Hydrogen and Oxygen gas, page 363. 45, COKNHILL, E.G., AND 122, BEGENT STBEET, W., LONDON. )69 Apparatus for negative and positive Collodion process, or for Paper and Collo- dion processes, page 553. for showing diminished bulk, 2135. for showing Electric Light in Vacuo, 2571, 2762, pages 438, 439. for showing magnetic curves, 1798. ,, for showing philosophical candle, 2136. for showing the impenetrability of matter, 3029. for submarine explosions, 2573. for weighing air, 2861 2863. hydro-pneumatic, 2175. Leslie's, for freezing water, 2887*. patent, for Ice making, page 507. Marcet's steam, 2946. Marsh's, 2688. Oersted's, 2661. Glass Blowers' patent, page 398. Photographic, complete seta of, page, 553 Polarising, page 277. Spectrum, pages 281, 282. Soda water, page 504. ., Taylor's Dialysis, page 395. Thermo-electric, page 450. , to exhibit vibration of elastic membrane, 3064. ,, to exhibit heating effects of elec- trical currents, 2422, 2423. to explain intermitting springs, 2920, 2921. . to illustrate curve of quickest descent, 3040. to illustrate expansion and con- traction, 2961, 2963. ,, to illustrate equilibrium of forces, 3043. to illustrate laws of collision, 3042. to illustrate laws of composition of force, 3038. to illustrate parabolic curve of projectiles, 3041. to illustrate ventilation, 2991. to produce sound by Hydrogen gas, 2136, 3056. to show expansion of liquids by heat, 2969. Benevide's Steam, 2948. Hysometrical, page 92. Electrical, page 412. Microscopic, pages, 256, 275. Wollaston's boiling point, 131. Apparatus, Paraffin or Petroleum Testing, page 170. Ure's Nitrogen, 2143. Sturgeon's 2692, 6281. Specific Gravity, pages 190, 390. to illustrate the construction of induction coils, 2706. ., for showing hyperbolic curve pro- duced by capillary attraction, 2936. to illustrate capillary attraction, Inertia, 3028. [2935. to illustrate the laws of central forces, 3044. for producing musical flames, 2760. Tyndall's, for producing Heat by friction, 2954 and page 482. Nitrous Oxide, 3116. Appold's Pumps, 2927. Approximate Height due to Barometric Pressure Table, pages 3 and 480. Aquarium Thermometer, 290. Archimedes' Screw, or Water Snail, 2929. Architect's Scales, 1233, 1565. Curves, page 342. Areometers, see Hydrometers, page 176. Argand Lamp, Microscopic, page 271. Spirit Lamps, page 403. Argentometer, 511. Armstrong's Hydro-Electric Machine, 3392. Aquarium Hydrometer, 461. Beads, 525. Arithmometer or Calculating Machine, page 349. Arrows for Land Chains, 1210*. Arsenic Apparatus, Marsh's, 2139. Tubes, 1911. Tube Funnel, 1911*. Artificial Horizons, page 312. Fountains, 2916. Aspirator, Brunner's, 1931. Metal, page 72. Astatic Needles, 2651. Astronomical Slides, 1803. Telescopes, pages 247 to 255. Atmidometer or Atmometer, Dr. Babington's, 127. Atmidoscope, Babinet, made to order. Atmospheric Electricity, pages 127 to 129.. Atmospheric pressure, Table of, pages 3, 480, and 557. Attwood's Machine, 3034, 3035. Auctioneers' Glasses, 1419. Auriscope, 3096. Automatic Photostat, see Electric Light Apparatus. 570 NEQEETTI AND ZAMBRA, HOLBOEN VIADUCT, E.G. Azimuth Compasses, page 321. Bachoffner's Electrepeter, 2701. Backgrounds, 3316. Bags, Gas, 1783, 1784. Balloon Barometers, page 12. Babington's Battery, 2520. Bain's Apparatus, 2682. Balance and Cork Experiment, 2885. Balances, Assay, and Chemical, pages 396 and 406. Balloons, 2157, 2159. Balloons of Glass, page 388. Balls, Electrical, Brass, &c., 2503. Bar Compound, for expansion, 2162. Barker's Mill, model of, 2928. B ark tro meter, 477. Barlow's Rotating Star, 2696 Double ditto, 2697. Bar Magnets, 2645. large, for Ship's use, 2647. Barograph, pages 19, 21, 30. Barometer, Cassini, and Benoulli's, page 14. Moreland's, page 14. ,, Hook's, page 14. Kew pattern, 15. Cases of Glass, 9. Testing Chamber, 10. Charts and instructions for keep- ing the record, page 132. ' Tubes, 2887. Barometers, pages 136 to 151. Gun, Admiral Fitzroy's, 18. Agricultural, page 144. Altitude, pages 10 and 11. Aneroid, pages 21 to 27, and page 148. ditto, Pocket or Watch size, 23, 24, 25. Chemical, page 11. ,. Boat, 28, and page 148. Bourdon's Metallic to order. Dial or Wheel, pages 136 to 138. .. . Farmers', page 144. Fisherman's. Admiral FitzRoy's, page 143. Howson's ditto, pages 14 and 15. Fortin's, pages 5 to 7. ,, principles of, explained, pages 2, 3. Laboratory, 13, 1913. ,, Long Range, 24*. Marine, ordinary, page 145. ,. ditto, with Sympiesometer, 181. ditto, Negretti and Zambra's Board of Trade Standard, 15. ditto, Marine, page 11. ,, Miners', page 144. Barometers, Mountain, pages 10, 11. Negretti and Zambra's ditto, 11. ditto, Gay Lussac's, 13, 14. ditto ditto Standard. 14. Negretti and Zambra's Long Range, Glycerine, page 18. Negretti and Zambra's Short Tube Mountain or Balloon, 19. . Glycerine, Jordan's, pages 17, 18. Negretti and Zambra's Standard, pages 4 to 13. Pediment or Upright, pages 140 to 144. Registering, pages 19, 27. Self Compensating and with Electrical adjustment, see N. and Z.'s Meteorological Treatise. History of, and described, pages 2 and 3. Self -registering Mercurial. Negretti and Zambra's improved, 25. ditto, King's, 26. Stands, ornamental for, page 150. Standard, pages 4 to 13. Self Recording Aneroid, pages 27, 28. Surveyors' and Engineers' Altitude, page 296. Observatory Standard. 5. Student's Standard, 20. Barometer, Vernier, described, pages 6, 7. Syphon Tube, page 11. ,, Ship's and Boats', page 149. McNeild's Long Range, 23. ,, Range of Scale magnified, page 14. Scales, comparison of English and Metric, page 3. Yacht, page 149. Water, page 17. Barometrical Thermometer, page 92. Baroscope, 2885. Bars, Compound, 2963. Bars of Antimony, &c., for testing:, 2163. Barrel, Stoneware, for water, 2083. Basins, Evaporating, 1958. Conical Glass, 2150. Berlin Porcelain, 1957, 1914. Bath, Hot Air, 2334. Water, 2115. Baths, Exciting or Nitrate of Silver, 3319, Batteries, Bunsen's Carbon, 2542. Babington's, 2520. ., Callan's Cast Iron, 2546. Daniell's, 2525. Electrical, 2394. Galvanic, Cruikshank's, 2518. 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 571 Batteries, Galvanic, Floating, De la Eire's, 2686. ,, Grove's, page 431. Grove's gas, 2540. Maynooth, 2544. ., Smee's, page 430. Sturgeon's, 2522. Wollaston's, 2520. ., Walker's, 2547. Sulphate of Mercury or Pile de Marie Davy, 2782, page 457. Per-oxide of Manganese, or Le Clanche's, 2554, page 433. Dr. Leeson's, 2548. Mullin's, 2528. Bichromate Bottle, 2551. Crosse's Water, 2541. ., Fuller's, 2553. Sulphate of Lead, 2549. Batteries, in s^ts, for Electric Light, page 437. Battery Cells, 2574. Plates, Amalgamated Zinc, 2582. Beaume's Hydrometer, 421, page 177. ditto for Soap, 422. Acidometer, 422. Saccharometer, 423. Bead's, Salt Water, 525. Specific Gravity, 524. Lovi's, 524. Glasgow, 526. Beaker Glasses, 1916. Tumblers, 1917. Beale's Neutral Tint Reflector or Camera Lucida, 962. Clinical Cabinet, 545. Beam Compasses, 1243. fittings, 1547. ., Tube, 1546. Beckley's Anemometer, page 110. Thermograph and Hygrometer, page 78. Magnetograph, Kew arrangement, page 130. Beer Dip Rules, page 345. Beetle Microscopes, 694. Bellows or Blowers, 2187, 2181. ., Hydrostatic, 2915. ., Organ, 3068. Bell Experiment for Air Pump. 2870. Bells, Electrical, pages 462 to 465. Fog, 1434. Berzelius' Sulphuretted Hydrogen Apparatus, 2129. Washing Bottle, 2117. Berlin Porcelain, page 376. Bichromate Battery, 2551. Bijou Opera Glasses, 805. Binding Screws, 2623. Binks' Alkalimeter, 1902. Binnacles, page 326. Binnacle Tops, 1424. Binocular Deer Stalking Glass, page 241. Microscopes, page 264. Opera and Race Glasses, page 234. Telescopes, Negretti and Zambra's improved, page 241. Biot's Electrical Apparatus, 2404. ., Polariscope, 1052. Bird's, Dr. Golding, Inversor, 2700. Vibrating Magnet, 2695. Bisulphide of Carbon Prisms, 1087. Black Mirrors, for Artists, 715. Bladder Ferrules, 2160. Frame and Weights, 2894. Glasses, 2868. Bladders, To Order. Blasting and Mining Apparatus, page 463. Blending Jars, 450* Blind Scale Brewer's Thermometers, 280. Blowing Machines, for Oil Lamp Furnace, page 2243*. Blowpipe, Black's, Bergman's, and Berzelius', 2166, 2167*. Pepys' and Wollaston's, 2167*. Apparatus, pocket, 2187. ,, Forceps, brass, &c. 2184. Gas and Steam, 2172. Hemming's Safety Oxy -hydrogen, 2168. jets, Platinum, 2163. minerals, in boxes, 2189. Oxy-Hydrogen, 2169. ,, Rose's, or Russian spirit, 2173. self-acting Spirit, 2170. Spoons, 2186. Tilley's Water Pressure, 2175. various, pages 397 to 399. Board of Trade Barometer, 15, page 11. Board of Trade Hydrometer. (see Hydrometers.) Board of Trade Thermometer, 40. Boards, Drawing, page 1642. Pressure, 1785. ,, Preparing, To Order. Boat Compasses, page 319. Barometer, 196. Bohnenberger's Electroscope, 164. ,, Machine, page 495, 2417. Boiling Point Apparatus, page 92. Boiling Points, Table of, page 133. 572 NEGEETTI AND ZAMBEA, HOLBOEN VIADUCT, B.C., Boiling Spring Kegistering Thermometers, Negretti and Zambra's patent, pages 42 and 171. Point Thermometers, page 93. Book Stereoscope, 784*. Bordering or Colouring Pens, 1524. Botanic Microscopes, pages 223, 256. Bottle latteries, 2551. Bottles, Berzelius' Washing, 2117. ., Acid, 1920. Capped, 1921. ,, Collodion, page 538. Cubic Inch, 2101, 1951. Dropping, 1963. ditto, Improved, 547, 3109. Elastic, 2198. Gmelin's Washing, 1920. ,. Gutta Percha, 2257. Specific Gravity, 529, 2074. Gas, 1990, page 375. Stoppered, &c. f page 377. Syphon Washing, 2120. Tube, 1923. Washing, page 393. Water, 2116. Woulffe's, 2125, 2127. Copper, 2862. Bochett's Microscope Lamp, 967. Bottling Machine for Soda Water Engines, page 504. Bourdon's Pressure Gauges, ) pages 206 to Vacuum ditto, j 210. Barometers, To Order. Boutigny's Experiment, 2985. Bow Dividers, 1514, 1516, Bow Pencils, 1509. Pens, 1512. Pens, double-jointed, 1511. Boxes, dark, improved, 2889. Draining, 3277. for Plates, 3274. Stained Wood, for Apparatus, made to order. Boyle's Law, page 476. Tube, 2914. Brass Balls and Wires for Leyden Jars, 2503. Chain, 2506. Clamps, 2510. Protractors, 1606. Breaking Squares, 2897. Brewers' Rules, page 345. BreWers' Thermometers, page 158. Brine Hydrometer, 468 / Brooches and Lockets, Gold and Plated, To Order. Brook's Apparatus, 3063. Brook's Double Nose Piece, 938. Brunner's Aspirator, 1931. Brushes for Electrotype, 2636. Photographic, page 548. Buckle's, 3290. Test Tube and Bottle, 2191. Bucket and Syphon, Electrical, 2453. Buffs, Polishing, To Order. Bulb, Tube, 1930. Bulbs, Turpentine, 2110. Bung Eods, 1662. Bunsen's Gas Burner or Furnace, page 403. Bunting and Flags, Supplied To Order. Burettes, 2041. Burnier's Compass, 5 5 6 6 Burning Glasses, 1716. Cabinets, Geological, page 503. Microscopic, 1040. ,, of Minerals and Shells, page 503. ,, Stereoscopic, page 233. Cadet's or Navy Sextant, page 308. Callan's Coils, 2705. Callan's Batteries, 2544. Calcining Pots, 1945. Callipers, Bow, 1702. Hull, 1701. Proportional. 1534 to 1537. Calorimotor, Wollaston's, 2523. Hare's, 2524. Calorometer, Hare's, 2424. Camel's Hair Brushes, page 548. Camera Backs Single, Double, or Swing, page 531. 3194. Fronts, Sliding, To Order. Shutter, Instantaneous,3169, 3284*. Stands, for Operating Room, &c., page 536. Cameras, Carte de Visite. 3188, 3197. Double Lens, ditto, page 352. Enlarging or Copying, To Order. Expanding or Folding, page 531. Folding and Sliding, page 531. for Paper Processes, page 528. Garden, page 226. Sliding or Shifting body, page 528. Kinn ear's, to order. ,, Lucida, for Microscopes, 960. Beale'B, 739. Wollaston's, 735. Stand for, 737. Microscopic copying, To Order. Micro- Photographic, To Order. Obscura, 740. Photographic, pages 528 to 533. 45, CORNHILL, E.C., AND 122, REGENT STREET, W., LONDON. 573 Camera, Portrait Boom, 3193. Satchel, 3199. Stereoscopic, page 522. ., . Solar, To Order. Tourist's, page 532, Trunk, 3193. Draughtsman's, 741. Universal Studio, 3193. Improved Portable Bellows, pages 529, 530. Cannon, Electrical, 2177, 2480. Electrophorous, 2389. Cailletet's Compression Pumps, 3194 to 3151. Cannon, Galvanic, 2572. Caoutchouc Connectors, 2195. Gas Bags, 2194. in Sheets, 2193. ,, Varnish, 2197. Vulcanised Tube, 2196. Water Bags or Bottles, 2198. Capstan, model of, 3049. Capsules, Berlin Porcelain, 1929. Evaporating, Platinum, &c., 2199. ., Glass, 1928. Captain's Night Glasses, 798. Cap Glasses, 675. Carbon Galvanic Battery, Bunsen's, 2542. Carbon Points, for Electric light, 2585. Carbon Plates, Cut to Order, 2587. Card Mounts, for Stereo pictures, 3324. for Carte de Visite, 3326. Carte de Visite, 3325. for large Views, To Order. Carte de Visite Cameras, 2850. Lenses, page 517. Cartesian Divers, 2937, 2938. Cartier's Hydrometers, 498. Cases, Camera, to Order. Cases, Telescope, 826. Cast Iron Galvanic Battery, 2544. Casts of Rare Fossils, page 503. Cataract Spectacles, G24. Cathetometer, 6 and 8. Cats' Skins prepared for Electrical Experi- ment, 2491. Cattle Gauge, 1708. Cattle Plague Thermometers, 311. Cavallo's Pith Ball Electroscope, 2414. Cavendish's Apparatus, 2131. Cells, Battery, 2574. Centre Pieces, Horn, 1636. Centesimal G alactometer, 495. Centrifugal Pump, Appold's, model of, 2527. Centrillinead, 1257. Chains, Gunter's, 1200. Metre, 1210. Jhain, Platinum and Silver, for Galvanic experiments, 2568. Chain Scales, 1571. Chain, Brass Electrical, 2506. Chains, Surveying or Legnd, page 301. Standard. 1211. hanging or Dark Boxes, Photographic. 3209. Charts, Admiralty and Official, To Order. Charts, Barometer and Thermometer, page 132. Chartometer, 1281, 1282, Chauffers, 2200. Chemical Apparatus, page 375. Cabinets, page 409. Labels, 2201. Lamps, page 403. Chemicals, Photographic, page 550. Chemical Weights, pages 408, 409. Weather Glass, page 147. Tests, to Order. Thermometers, pages 407 and 408. Chlorimeters, 1902. Chinese Fireworks, page 365. Chladni's Acoustic Figures, 3064. Chloride of Calcium Tube, 1935. Chrondrometer, 1688. Chromatropes, 1815*, 1817. Chromeidoscope, 747. Chronograph, 1189. Chronometers, To Order. Chronometrical Pyrometer Thermom eter, 595 Circular Glass Plates, for Machines, 2494. Ebonite, ditto, 2495. ,, Protractors, page 340. Circumferentor, page 291. Citrometer, 480. Civil Engineers' Sets of Drawing Instruments, 1482, 1486. Clamps, Brass and Iron, 2510. Clark's Gas Bottle, 1989. Retort and Receiver. 2055. ,, Arsenic Apparatus, 2141. Claude Lorraine Glasses, 723. Clinometer or Inclinometer, page 299. Clip-nose Spectacles, page 216. Clips, Wood and Glass, page 548. Clinical Cabinet, Dr. L. Beales, 545. Clinical Thermometers, pages 160, 500. Cloth, Transfer or Tracing, 1644, 1645. Clocks, Astronomical, To Order. Clockwork Motion for Lime Holder, page 359, and 1788. Cloud Mirror, Goddard's, To Order. Coddington's Lenses, 709. Coil Machines, for Medical Galvanism, pages 455 to 459. 574 NEGEETTI AND ZAMBRA, HOLBOBN VIADUCT, E.G., Coils, Callan's Primary and Secondary, 2705. Kuhmkorff's Induction, page 451. Collecting Bottles and Tubes, 1024. Collector's Pocket Microscopes, 997. Colour Disc, Prismatic, 725. Collodion Bottles, or Pourer, 3237. ., Cometless, 3237*. Filters, 3237f. Collodion, various, Negative and Positive, page 502. Colouring Magic Lantern Slides, see Manual. Pens, 1524. Colours, Water, in Boxes, page 344. Colliery Barometer, 174.] Signal Bell, Electro, 2796. Colours for Glass Painting, 1884. Photographic, 1660. Colour Tops, 724. Combustion of Charcoal by Electricity, Stand for, 2255. ,, Furnace, 2202. Tube, 2005. Comic Slides for Magic Lanterns, shifting, page 364. Compass, Amplitude, 1377. Azimuth, 1384 to 1386. Boat, page 319, 1388. Watch Chain, page 317. ,, fitted to Telescope, To Order. Geological, page 315. Hanging or Cabin, 1380. Mariner's pocket, pages 314 to 319. ,, Masthead, various sizes and prices. 1428, page 322. Military, page 293. Kater's, 1166. Tell Tale, 1382. Liquid or Spirit, 321. 5 , Miners', page 292. Needles, 2648. Prismatic, page 293. ,, Improved, 1170*. ,, Azimuth, page 321. Eitchie's 321, 322. Symon's True North, 1363. Singer's Patent, 1341. Starlight or Moonlight, 1360. Steering, pages 320, 321. ,, Storm, 1373, 1374. ., Sun Dial, page 317, 318. Trinket, page 317. Universal Sun Dial, page 317. Watch Case, 1344. ., Gregory's Equestrian, 1361. ,, Ordnance Pattern, page 307. Snow Harris's arrangement, 1386. Compass, Sine, 2375. Hutchinson's Prismatic, 1174. ,, Surveyor's Pocket, 1184. ,, Burnier's, To Order. Compasses, Beam, Ordnance Pattern, page 307. (Trammel's) 1243. ,, plain, 1546, 1547. ,, Cutting, 1647. Drawing or Dividers, page 335. Triangular, 1531. Elliptical, 1533. Napier's Pocket, 1539. Pillar, 1541 to 1544. ,, Proportional, 1534. Tube, 1549. Tube Beam, 1546. Whole-and-half, 1545. Composition Frames, To Order. Composition and decomposition of light, apparatus to illustrate, pages 225 to 227. Compound Electro-Magnetic Apparatus,2704. Frames and Wires, 2721. ,, Magnets, 2644. Microscopes, page 256. Compound Bar, 2724, 2963. Compressormm, 988. Computing Scale, 1264. Commutator, 2699. Concave and Convex Mirrors, 713. Concave Lenses, for engravings, 727. Condensing Lenses, made To Order. Condensing Syringe, 2851. Condensing Pumps, 2954, 3149. Condenser, Hygrometer, 88. Condenser, Achromatic, 943. Electrical, 2412. for Microscopes, 940. Liebig's, 2211. Parabolic, Shadbolt's, 942. Pocket Fire Syringe, 2960. Conducting Wires, 2507, 2584, 2771. Conductor, Luminous, 2452. for Electrical Machines, 2496. Lightning, pages 127 to 129. Conducting Tube, 2196. Cone, Double, 3032. Confectioners' Hydrometers, 470. Thermometers, 351. Conical Mirrors, 734. Connecting Pieces, Ferrules, 2204. Tube, 1932, 1786. Convection Apparatus, 2989. Cooper's Pieceiver, 1946. Copper Bottle, with Balance, for weighing air, 2862. 45, CORNHILL, E.O., AND 122, EEGENT STREET, W., LONDON. Copper Bottle, improved form, 2863. Copper Disc, rotation of, 2694. Coronet or Diadem Vacuum Tubes, 2749. Concentric Stage, Natchet's, fitted to order. Copper Wire, insulated with Gutta Percha, 2719. covered with Cotton, Silk, and Gutta Perch , page 449. Copper Wire Table of relative lengths and weights, page 455. Copying or Pressure Frames, page 546. Cork Borers, 2215, 2217. Corn Balance or Chrondrometer, 1688. Cosmoramic Glasses, 730. Camera, 742. ,, Stereoscopes, 771. Crooke's Radiometer, page 276. Cosmoscope, Frith's, supplied to order. Couch or Malt House Kod, 1684, 1685. Couronne de Tass, Volta's, 2515. Comparative Table of Foreign and English Measures of Length, see Appendix. Crayon Holders, 1641. Creamometer, 485. Cream Test Tubes and Jars, page 186. Cross of Metal, for experiments on conduction of heat, 2203, 2971. Cross Sight, Surveyors', page 292. Crossley's Rain Gauge, 120. ,, Recording Anemometer, page 111. Crucibles, Berlin Porcelain, 1943. cases and covers, 1939. Hessian, 1937. jacket, 1939. London fire-clay, 1938. Platinum, &c., 2206. round, 1942. skittle shaped, 1941. Stands and Supports, 2302, 2332. Tongs, 2209. ., Wedgwood, 1940. Cruikshank's Galvanic Batteries, 2518. Cryophorous, Wollaston's, 1948. Crystal Varnish, 4014. Crystals, Polarizing, various plates of, pages 1075, 1076. Cubic Inch Bottles, 1951, 2077. Measures, 1949. Tubes, 1950. Cubical Vessel, Tin, 2978. Cubing Rule, 1703. Cup Reflector, or Lieberkuhn, 949. Current Meters, 1190. Cuthbertson's Self-acting Balance Discharger, 2409. Cntting Diamonds, 2225. Cutting or Shaping Glasses. 3286. Knives, 3287. Curtain Effect for Lantern, 1826. Curves, Ship ; 1633. Architectural, 1630. ,. Mathematical, 1629. Radii, 1631. Railway, 1632. Curves, Ebonite, 1634. Cylindrical Gas Jars, 1894. Cylinders, Electrical, for Machines, 2493. Cylinders of Lime, 1795. of Wire, Gauze, Electrical, 2487. Cylindrical Lenses, 732. Mirrors, 733. Daguerreotype Apparatus, To Order. Damp Detector, 1346. Daniell's Galvanic Batteries, 2525. Hygrometer, 85. Pyrometer, 596, 2956. Dark Box, Negretti and Zambra's Improved, page 487. Dark Lanterns, 3230. Dark Slides or Backs for Cameras, page 531. Dark Tent, page 534. Dark Wells or Stops, for Microscopes, 954*. Davy's Safety Lamp for Miners, 2264, 2993. Day and Night Telescopes, 831. Debuscope, 748. Decimal Weights, 2222. Deck Glasses and Prisms, page 322. Deck Telescopes, 839. Decomposition of Water, Apparatus for, 2560 to 2567. Deer Stalking Glasses, 828, 829. ., Binocular, page 241. Deep Sea Sounding Thermometers, Negretti and Zambra's, pages 66, 67. De Londe's Lightning Plate, 2435. Deflagrating Jars (see Gas Jars and Receivers Spoon, 2218. Deflecting Needles, 2648. De la Rive's Floating Battery, 2686. De la Rue's Electrical Discharger, 2680. De Luc's Pile, 2415. Densimeter, Gay Lussac's. 509. Rousseau's, 510. Fahrenheit's, 502. Dentists' Blowpipes, pages 397, 399. ,, Mirrors, 3111. Designs, Selenite, 10G8. Dessicating Jars, 1965. and Tubes, 1967. Detector Galvanometer, 2674. 576 NEGEETTI AND ZAMBRA, HOLBORN VIADUCT, E.G., Developing Glasses, 3239. Dishes, 3270. ., Box, page 534. Devices, Electrical, on Glass, 2431/2434. Diagonal Barometer, page 14. Print Machines, 729. Kods, Double, 1666. Diagrams illustrating Astronomy, Geography, Geology, various Steam Engines and Machines, &c., 3019, 3123. Dialysis, apparatus for, 2148, 1964, page 395. Dials, Sun, page 312. Diamond Jars, Electrical, 2437. Diamonds, writing and cutting. 2224, 2225. for Cutting Thin Glass Circles, 1005. Dial Barometer, described, page 134. to make portable, page 135. Dicas' and Allan's Hydrometers, 434. Dials, Surveyors' and Miners', page 291. Pocket Sun, page 317 and 318. Dioptric Ship Signal Lamps (Oliver's Patent)? to order. Dioramic Lantern Slides and Effects, page 366. Dipleidoscope, 1187. Dippers, Glass and Porcelain, page 542. ., Silver, 3269. Dipping Needles, 2660, 3135. Baths, page 541. Drosometer, see page 68. Directors for Medical Galvanic and Electrical Apparatus, 2400, page 456. Discharger, Cuthbertson's Steelyard, 2409. Electrical. 2397. Henley's Universal, 2407. Jointed, 2397. Dishes, Evaporating, 1958. ., Glass Exciting, 3272. Metal, 2226, 3122. Porcelain Washing, page 542. Sulphuric Acid, 2086. Berlin Ware, 1957. Gutta Percha and Ebonite, 3271. Platinum, 2231. Dish, Zinc, 3296. Dissecting Forceps, 970. Instruments, cases of 983. Knives, 979. Needles, 975. Scissors, 976. Dissolving View Apparatus, page 356. Slides, page 366. with Oxy-calcium Light, 358. Dissolving View Apparatus with Oxy- hydrogen Light, page 359, and see Manual. Distillers' Rules, page 345. Divided Tube, 1998. Dividers, page 334. Hair, 1500. Pocket, 1506. Dip Circle, Kew Pattern, 136. Dividers, Spring, 1508. Steel Spring Bow, 1512. with pen and pencil joints. 1512, 1513. Turn-in, 1506. Dividing Engine, page 31. Diving Bell, model of, 2939. Apparatus, pages 505, 507. Disinfecting Thermometers, 379*. Distilling Apparatus for Beer and Spirits, page 193. Dobereiner's Extracting Apparatus, 2133. Lamp, 2270, 2009. Donovan's Apparatus, 2132. Dotting Pens, 1525. Double Cone and Inclined Plane, 3032. Double Tube Deep Sea Thermometer, Negretti and Zambra's, pages 60 to 67. Drainage Levels, page 287. Drainers for Crystals, 1953. Draining Boxes or Racks, 2946. Draughtsman's Camera Obscura, 740. Drawing Boards, 1642 and page 307. Instruments, Regulation sets of, page 306. School sets of, 1557*. Ordnance Pattern, page 1479. ., Addiscombe or Cadet's. 1478, 1478* Woolwich, 1481. Civil Engineers', 1482. King's College, 1482. Magazine Sets, 1486. Swiss or French, 1557*. Pencils for Instruments, 1639. Pens, page 336, 338. Pins, 1637. Scales, pages 339, 343. Squares, page 342. Dropping Bottles, 1963. Tubes, 1961. Bottles, Improved, 3109, 547. Tube, Pneumatic, 547*. Dry Collodion Plates, page 553. Dry and Wet Bulb Hygrometers, pages 68 to 80. Drying Apparatus, 2220, 2333. 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 577 Du Bois Kaymond's Galvanometer, 2671. Dubosq's Spectroscope, 1081. Electric Lamp, 2559. Duchess Opera Glasses, 802. Dumas' Gas Tubes, 1999. Dumpy Levels, 286. Duckham's Patent Weighing Machine and Dynamometer, 592, page 202. Dia-Magnetic Experiment, 2703. Dialyser, A. S. Taylor's, page 395. Dynamometer, Schaeffer's, 609. Dynamo- Magneto-Electric Machines, 2604> page 439. Ear Illuminator, Jordan's, 3093. Electrical, 2754. Earth or Ground Thermometer, pages 34, 35, 42 and 43. Earth Temperatures, page 172. Ebonite or Vulcanite Goods. Baths, Forceps, Funnels, Trays, supplied to order. Curves, Scales, Rules, &c., 1634. Battery Cells, 2578. Electrical Machine, 2383. Educational Microscopes, pages 258, 259. Electrepeter, 2699. Bachoffner's, 2701. Dr. G. Bird's, 2700. Electrical Amalgam, 2505. Apparatus, pages 412 to 427. Apparatus for igniting gunpowder, &c., 2474. Batteries, 2394. Bells, pages 422 and 460. Bird, 2433. ,, Bomb or Mortar, 2481, 2572. ., Brass Balls, 2503. Bucket and Syphon, 2453' Cannon, 2477. Chain, 2506, 2436. Column, De Luc's, 2415. Condenser, 2425. Conductors, 2496. Conducting Wire, Flexible, 2507. ,. Cylinders of glass for machines* 2493. Dancing Figures, 2442. Diamond Jars, 2437. Directors, Medical. 2400. ., Discharger, Henley's, 2407. Cuthbertson's, 2409. De La Rue's, 2680. Electricity, Collection of, page 119. ,. Atmospheric, 162. Electrical Apparatus, Biot's, 2404. Dischargers, page 416. Electrical Egg Stand, 2438. Egg Stand, Faraday's, 2439. Falling Star, 2452, 2571. Figures, 2446. Flask, 2450. Fly or Wheel, 2462. Fire House, 2472. Gamut of Bells, 2458. Glass Handles, 2499. Glass Legs and Rods, 2502. Glass Tubes and Cylinders for excitation, 2490. Globe, 2451, 2557. Gutta Percha Supports, 2501. Hand Spiral, 2454. Head of Hair, 2445. Image Plates, 2440. Inclined Plane, 2468. Jars for Frankliniau Experiment, 2402. Lamp, 2596. Lamp, Duboscq's, 2558, 2559. Lightning Plates, 2435. Luminous Chain. 2436, 2456. Conductors, 2496. Powder Cannon, 2572. Machine, Cylinder, 2377. complete with apparatus, 2379. Plate, 2380 to 2384. Vulcanite Plate, 2383. Woodward's, 2382. Piche's, 2391. Ramsden's, 2380. Nairne r s, 2377. Armstrong's, 3392. Winter's, 2381. Holtz', 2383. Wimshurt's, 2391*. Voss's, 2390. Magic Picture, 2427. Mill, 2466. Names or Words, 2431. Orrery or Planitarium, 2465. Painted Glass Plane, 2434. Plates of glass, for Machines, 2494. Plates, Ebonite, for ditto, 2495. Pile, De Luc's, 2415. Zamboni's, 2416. Pistol. 2478. Pith Balls, 2444*. Pith Ball Stand, 2443. Pith Figures, 2442. . Plumes, glass and paper, 2449. Powder House, 2473. Spirals, Revolving, 2455, 2457. 2 P 578 NEGRETTI AND ZAMBRA, HOLBOEN VIADUCT, E.G., Electrical Shellac Cylinders, for excitation, 2488. Spider, 2448. Sportsman, 2476. See Saw, 2467. Star, 2432. Stools, 2429. Swan, 2446. Thunder Cloud Apparatus, 2469. Harris's, 2470. Thunder House, 2471. Wheel, Franklin's, 2464. Rubber, Fur, 2491. i> Egg, 2451. Electro- Galvanic Coil Machines, pages 455 to 458- Electro-Gilding Apparatus, Single Cell, 2616. Battery process, 2619. Electric Lantern, 2602. Light, Apparatus for, page 437. Carbon Points for, 2586 and 2598. Electro-Magnetic Apparatus, Compound, 2404. Sets of, 2720. Bell Experiment, for Air Pump, 2871. Motive Engines, page 448. Signal Bell, 2715, pages 460 to 465. Electro-Magnets, 2664. Electrometer Balance, 2409, 2410. Dr. Milner's, 168, 2418. Harris's Unit Jar, 2420. Henley's Quadrant, 2413. ,. Peltier's, 168, 2418. Electrometer, for Atmospheric Electricity, 163. Cavallo's, 166. Coulomb's Torsion, 2406. Harris's Balance Beam, 2419. Professor Thompson's Amospheric, 170. Thomson's Quadrant, 169. Volta's, 165, 2483. Electroscope, Bennett's Gold Leaf, 2411. Bohnenberger's, 164, 2417. Cavallo's Pith Ball, or Straw, 2414. Cottrell's, 7s. 6d. Saussure's, 2421. Singer's, 163. Electro-Thermometer, Harris's, 2420, 2422. Kinnersley's, 2423. Electrotype Apparatus, Single Cell, page 440. Battery Process, page 441. Electrotype Materials, page 442. Elipsographs, 1258. Eidograph, Wallace's, To Order, 1263. Elliott's Syphon Washing Trough, 3273. Elliptical Drawing Compasses, 1533. Electricity, Atmospheric, page 112. Electric Light in Vacuo, 2557, 2762, 2601. Electro-Magnetic Locomotive and Bail, 2713. Eudiometrical Tubes, page 380. Electrophorous, Volta's, 2387. Improved Vulcanite, 2388, Cannon, 2389. Eleaometer, 473, page 169. Empress Opera Glasses, 792. Engineers' Rule, 1698. Sets of Drawing Instrments, 1482 ? 1287. Engine Counter, page 201. Harding's, 591. Wheattsone's, page 467. Dividing, page 31. Engines, Steam, &c., pages 211, 481 to 490. Engravers, Magnifiers, 700. Ensigns, Flags, &c. To Order, see also 1731. Engineers' Thermometers, page 157, 167, 174. Equatorial Telescopes and Stands, page 252. ^Ethriscope, Leslie's, 62. Estimates for Sets of Meteorological Apparatus, pages 123, 124, and 125, Photographic Apparatus, page 553. . Magic Lantern and Dissolving View Apparatus, pages 350 to 374. Ettling's Gas Transferrers, 1969. Eudiometers, 1970, 1971. Evaporating Capsules, Platinum, 2199. Dishes (see Dishes and Basins). Gauge or Evaporometer, 126. Everest's Theodolite, 1114, 1118. Exploder, Magnetic, 2808. Exciting or Nitrate of Silver Bath. 3319. Exhausting Syringe, 2850. Expansion of Solids and Fluids, Table of, page 560. Extracting Apparatus, Dobereiner's, 2133. Eye Protectors, page 219. Eye Shades, 3114. Transparent, Occhiombra, 3115. Eye Glasses, page 218. Eye, model of, 745. Eye Piece, Polarising, 1063. Eye Pieces for Microscopes, page 269. Erecting, 932, 933. Eckhold's Omnimeter 1142. 45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 579 Eye Pieces for Telescopes, page 255. Micrometer, 878, 934. Orthoscopic, Kellner's, To Order. Eye Tubes, Pancratic, Dr. Kitchener's, 825. Falling Star Apparatus, 2452, 2571. Faraday's Apparatus for Decompositions, 2666. Egg Stand, 2439. Kotating Wire, 2689. with Marsh's Experiment, 2690. Brush Director, 2781. Convection Apparatus, 2989. Electrical Net, 2486. Farmer's Barometer, page 144. Ferguson's Pyrometer, 538, 2958. Ferrules, 2205. Field Glasses, page 234. Eock Crystal Lens, page 808. Field's Patent Alcoholmeter, 548, page 193. Field's Differential, or Katie-Micro Polariscope, 928. Files, 2232. Filter Boxes, 2240. Paper, 2236. Circles, 2237. Kings, 1979,3248. Filtering Cup, 2864. Filters, Stoneware, 283. Finger-stalls, India-rubber, 3294. Fishing Tubes, 1001. Fish, Magnetic, 2683. Fittings, &c., for Ships 1 Lamps, page 322. FitzRoy's Barometer, page 143. Rain Gauge, 114. Registering Thermometer, 341. Fixing Stands, page 538. Fire Syringe, 2859, 2960. Flags, Signal, 1731, and To Order. Flasks, page 380. Electrical, 2450. Graduated, 1976. mounted with Stopcock, 1975. 2861. Tube, 2103. Flat Brass Plate and Sliding Wire, 2858. Fletcher's Patent Blowpipes, To Order. Flexible Tube, Metal, 2234. Conducting Wires, 2717. Flint Glass Tubing, 2004. Flint and Steel Apparatus, 2896. Florentine Receiver, 2072. Flower Microscopes, 691. Fly, Electrical, 2462. Floating Thermometer, Aquarium, 290. Bath, page 159. Float Rod or Bung Gauge, 1676. Focussing Glasses, or Visuometer, 761, 3302 Fog Horn, 1432. Hand Bells, 1434. Signal, (Key's Patent), 1435. Forceps, Blowpipe, 2184. Boxwood, 972, 3298. Glass, 3292. Horn, 3297. Ebonite, 3300. Microscopic, page 271. Platinum, 2185, 2285. Spectroscope, 1093. three-pronged. 981. Stage, 974. Force Pump, model of, 2882. Forge, portable, 2244 to 2247*. Fossils, Casts of, page 503. Foucault's Gyroscope, page 495. described, page 495. Reflecting Telescope, 884. Fountain, Artificial, 2916. Glasses, 1905. in Vacuo, 2866, Jets, 2917. Slides, for Lantern, 1821. Folding or Book Stereoscope, 784*. Folding Dividers, 1506. Spectacles, page 211. Foot or Hand Blowers for Furnace, page 398. Fortin's Barometer, pages 5 to 7. Fox's Circle or Inclinometer, 3137. Fox Brush, Electrical, 2492. Frames, Copying or Pressure, page 546. for Photographic Pictures, Supplied to Order. Gutta Percha and Composition, Ormolu, Papier Mache, To Order. Freezing Points, Table of, see Appendix and page 169. Fritzch's Apparatus for Alkalies, 2134. Frog Plate, 990. Fruit Stand, 2865. Fiye's Lactometer, page 185. Funnels, for Gas Bottles, 1982. Ebonite, 2241*. for Retorts, 2067. Glass, page 381. Gutta Percha, 2241. with Handle, 1984. Metal, 2222. with Stopcock, 2071. Safety, 2068, 2070. Tube, 1982. Bent Tube, 2067. Separating, 2071. Wedgwood Ware, 1981. 2 P2 580 NEGEETTI AND ZAMBEA, HOLBORtf VIADUCT, E.G., Funnel, with Stopper, 1985. Furnace, Gas, or burners, page 402. Blower, 2181. Oil Lamp, To Order. various, pages 397, 401. Fusees, Abel's, page^GS. Galactoscope or Galactometer (see Lacto- meter). Galvanic Apparatus, complete sets of, 2589. Batteries, pages 428 to 434. Galvanometer, pages 444, 445. Detector, 2674. Thompson's Reflecting, 2707. Sine, 2672. Quadrant, 2676. Galvanic Coil Machines, page 455. Gamut of Bells, on stand, with Eitchie's experiment, 2679. Garden Camera Obscura, 742. Gardener's Microscopes, 692, and page 223. Thermometers, page 156, and No. 324. Gas Absorber, Liebig's, 2000. Apparatus, pages 382,383. Bags for Oxy-Hydrogen Apparatus, 1783, 1784. Caoutchouc, 2194. Blowpipes, page 397. Bottles, 1990, 1991. Bottle, Clark's, 1989. Bottle with Washing Vessel, 1989. Burners and Stands, page 403. Furnace, Bunsen's, or Burner, 2252. Holder, Pepys', 2286. Jars, pages 375, 382. Jet, Hemming's, 2168. Lamp with Condenser, 2254. Pressure Gauges, page 197. Purifier, 1781. Receivers, 1993. ,, Receivers, mounted, 1994. Retorts, 1992. Transferors, Ettling's, 1969. Tube, Dumas's, 1999. Kerr's, 2001. Tubes, graduated, 1998. Gas Generator, 1778, 1780. Burners, 2252. Lamp for Spectroscope, or Burners, Bunsen's, 1092. Gas Testing Apparatus, page 497. 5 > Glover's, page 497. Pressure Gauge, Board of Works, 571. Engines, pages 510, 511. Lighting Apparatus, 3153. Gas Jet for Singing Flames, 3146. Jars, Glass, pages 375 and 382. Gassiot's Cascade, 2752. Vacuum Tubes, 2742. Revolving Star, 2752*. Gauges, Steam Pressure, ] Bourdon's pages 206 to 210. Vacuum, Bourdon's ] Transparent Dial, 606. Gauge Tubes for Steam Boilers, page 197. Bung, 1676. Gauge, Brass, for experiments on expansion by heat, 2961. Cattle and Horse, 1707, 1708. Combined Steam Pressure and Vacuum, page 207, No. 507. Evaporating, 126, page 89. Gas Inspectors, 572. Gas Pressure, 567. Hydraulic, 608, 612. Hydraulic Pressure, Bourdon's, page 612. Rain, page 83. Rope, 1705. Snow (made To Order). Steam, pages 205 to 210. Pressure, Mercurial, 174. King's Gas Pressure, 3038. Steam Pressure, Schaffer's, page 205. Thermometric Pressure, 412, page 174. Tide, 3157, page 120. Tubes, page 197. Vacuum, Bourdon's, page 207. Vacuum, for Air Pump, 2857. Water for Boilers, 565, page 197. Gauging Rods and Rules, &c., page 345. Gauntlett's Pyrometer, page 203. Gauze Wire, 2350. Gay Lussac's Alkalimeter, 1904. Alcoholmeter. 499. Barometer, 13, 14. Densimeter, 509. Volumeter, 508. Gazogene or Soda Water Apparatus, To Order. Geissler's Vacuum Tubes, page 452. Geological Cabinets, page 503. Compass, 1342. Geometrical Solids and Planes, 3051. German Glass Combustion Tubing, 2005. Tubing, 2003. German Silver Drawing Instruments, pages 331, 332. Ghost apparatus, to 'produce, see Negretti and Zambra's Lantern Manual. 45, CORNH1LL, E.G., AND 122, REGENT STREET, W., LONDON. 581 Gilt Mats, German and American, supplied to order. Glaisher's. Tables, page 133. Rain Gauge, page 81. Thermometer Stand, page 79. Glass Battery Cells, 2577. Blowers' Lamps, 2178. Table, pages 397, 398. Cells,mounted,for Electro- Gilding. 2617. Dippers, page 542. Exciting Baths, page 541. Slabs, or Covers, 2002. Figures, or Cartesian Divers, 2937, Funnels, page 381. Globe, Electric, 2557. Globe and Stop-cock, very light, 2861. Greyed or Ground, various sizes, cut To Order. Inhalers, 2008. ,, Legs and Handles, Electrical, 2499 and 2501. Glass, Microscopic, thin, 994, 995. Models, for teaching Geometry and Crystallography, 3050. ., Paintings, Colours for, 1884. Percolator, 2040. Prisms, 717, 719. Plates, ground, for air jars, 2002. Plates, Photographic, page 544. Plates to illustrate capillary attraction, 2936. Glass Receivers' Air Pump, page 475. Opal, page 544. ., Kings and Cells, for Microscopic Mountings, 991. Eod, 2C07. Rod for Electrical Apparatus, 2502. Rods, Photographic, 2080. ,, Slides, for Microscopes, 993. Spirit Lamps, 2078. Stage Plates, 992. Stop-cocks, 2054. Syphons, pages 390, 391. Syringes, page 392. Tinted, for Photographic Rooms, To Order. Trough, for holding Microscopic Objects, 985, 1798. Tubing, 2003, 2005. Unannealed, 1060. Water Trough, 985, 1798. Glasses, Auctioneers', 1419. Bladder, 2868. Burning, 716. Glasses, Cutting or Shaping, page 547. Eye, page 218. for Focussing, 3303. for Developing, 3239. Quadrant and Sextant, page 310. Fountain, 2905. Globular Receiver, 1996. Green and Ruby, for Ship's Lamps, page 322. Hand or Folders, pages 215 to 217. Hour or Minute, page 325. Lamp, for Magic Lanterns, page Parting, 2029. [363. ,. Perspective, 813. Phillips' Test, 2043. Pouring, for Collodion, 3237. Precipitating, 2042. Reading, 682. Shooting or Cap, 675. Tea Brokers', 1418. Test, various, 2099. Time, page 325. Globes, page 328. Covers for, 1451. Quadrants of Altitude for, 1452. Glasgow Beads, 526. Gmelin's Washing Bottle, 2119. Goggles, or Eye Protectors, page 220. Gold Leaf Electroscope, Bennett's, 2411. Goniometer, Wollaston's, 753. Gorham's Kaleidoscope Colour Top, 724. Gould's Microscope, To Order. Graduated Air or Gas Jars, 1901, 1998. Flasks, 1976. Gas Tubes, 1998. Measures, 2014 to 2019. Grain Scales, 2306. Gravatt's Level, 1119. Gravimeter, Nicholson's, page 190. Gravimeter, Directions for use of, page 191. Grove's Galvanic Battery, page 431. Gas Battery, 2540. Graphite or Carbon Points, 2586. Plates cut To Order. Graphometers, 1156. Graphoscope, page 228. Ground or Earth Thermometers, page 34. tt ,, Negretti and Zambra's Improved, page 171. Guinea and Feather Apparatus, 2877. Glass for, 2904. Gun Barometer, Negretti and Zambra's, 18. Gun and Shot Rules. 1238. Gun Lock Experiment for Air Pump, 2896. Gunner's Rules, 1602. Gravesand's Ball and Ring, 2962. 582 NEGEETTI AND ZAMBEA, HOLBORN VIADUCT, E.G., Gunter's Measuring Chain, 1207. Scales, 1595, 1597. Gutta Percha Battery Cells, 2579. Bottles, 2257. Exciting Baths, page 540. Frames, for Passe Partout, To Order. Funnels, 2241. ,. Goods, Various, 2256. Gyle Tun Thermometers, 283. Gyroscope, page 495. described, pages 495, 496. Hair Dividers, 1500. Hammers, Mineralogical, 2258. ;, Water, 2112. Hand Folding Spectacles, page 215. Hand Glass for Air Pump, 2869. Handles, Electrical Glass, 2499. Hanging or Cabin Compasses, page 320. Hare's Calorometer, 25U4. Harpoon Log, Walker's, 1390. Harpoon Sounding Machine, 1393. Harris's Balance Beam Electrometer, 2419. Electro-Thermometer, 2422. ,. Electrical Machine, To Order. Unit Jar, 2420. Thunder Cloud Experiment, 2470. Hall Thermometers, page 153. Halleur's Wind Vane, 135. Harbour and Pier Head Lights, page 224. Hand Magnifiers, pages 221, 222. Hay Stack Thermometer, 355. Head of Hair, Electrical, 2445. Head Rests, page 537. Heat, Apparatus to illustrate, page 513. Hedley's Circumferenter, 1154. Helio- Pyrometer, or Solar Intensity Appa- ratus, page 60, 56. Heliograph, page 512. Heliostat, Spencer's, 1737. Hero's Steam Engine, 2997. Hemisphere, Magdeburg." 2872. Hemming's Blowpipe, Safety, 2168. Henley's Quadrant Electrometer, 2413. Universal Discharger, 2407. Hints for Applying Medical Galvanism, page 458. Hittorf's Apparatus, 21/. Horizons, Artificial, page 312. Horizon Sweeps, page 234, Fig A. Horn Centres, 1636. Forceps, 3297. Horse Eule or Gauge, 1707. Horse-shoe Magnets, 2643. Compound, 2644. Horse-shoe Magnets on foot, 2685. Horsford's Nitrogen Apparatus, 2145. Horticultural Self- RegisteringThermometers, Negretti and Zambra's, 324. Hot Air Bath, Taylor's, 2334. Air Thermometers, 368. Water ditto, 364. Blast ditto, 370. Blast Blowpipes, 2180. Hour and Half-hour Glasses, page 325. Hourly Recording Thermometers, pages 52 to 56. How's Salinometer, 521. Howson's Long Range Barometer, page 14. Human Eye, Model of, 745. Hutchinson's Spirometer, 3088. Hydraulic Pressure Gauge, page 209. Machinery, Presses and Pumps, page 509, Hydrogen Balloons, 2157. Gas Apparatus, 1990. Gas Generator, 2248. ,, Lamps, for instantaneous light, 2270. Hydrometers, page 176. Aquarium, 461. Beaume's, 421, 423, 471. Board of Trade, Marine, 462. Carrier's, 498. for Chlorine Solutions, 468. Gay Lussac's, or Alcoholmeter, 499, 509. Combined with Saccharometer, 446. for Lemon Juice or Citric Acid, 480. for Soap or Soap Ley, 472. for Syrups, 470. for Wine, 469. ., Negretti and Zambra's Improved, 557. , , Photographic or Argentometer , 511. Richter and Tralle's, 503. Scheefer's, 497. small Glass, 452, 453. Specific Gravity, 419, 420. Sikes', or Sykes', brass, 427, page 178. Sykes' Glass, 425. Sikes', described, page 178. Standard Brass, 431. Pocket, 432. Hydrometer, Fahrenheit's, 501. Nicholson's, 533. Normal Alcoholmeter, 504. Dicas's and Allan's, 434. Paraffin or Petroleum Standard, 419. 45, COENHILL, E.G., AND 122, BEGENT STEEET, W., LONDON. 583 Hydrometer, for Oils, Oleometer, 393, 473, for Vinegar, 476. Government Proof, 424. ditto, for Brine, 468. Test Jars, 512. Twaddell's, 456, 459. Universal, 465. Tables, Baker's, Comparative, 496, page 558. Negretti and Zambra's Improved Patent Strengthened Stem, page 557. Hermbstadt's Combined, 507. Wooley's, 505. Eoberts', 469. Eleaometer, 393. Hydrometers described, page 176. Hydrometer Sliding Rules, 1670 to 1672. Hydro-Pyrometer, Bystrom's, page 203. Hydroscope, 1202*. Hydro-oxygen Gas Microscope, page 282. Hydro-Pneumatic Apparatus, 2175. Hydrostatic Bellows, 2915. Paradox, 2910. Press, Bramah's model of, 2940. Hygrometers described, page 68. Hygrometer Screen, page 99. Hygrometric Tables, page 76. Hygrometer Standard, 94. Hygrometers, pages 68 to 80. Instructions for use of, page 77. Daniell's, 85. Jones's, 86. Leslie's Thermometric, 84. Masons' 91 to 93. Oat-beard, 1346. Portable, 96. Regnault's, 87 and 88. Registering, 78 and 80. Negretti and Zambra's Improved Self- Recording, page 78. Beckley's ditto, 104. ,, Saussure's, 83. Wet and Dry Bulb, pages 73, 74. Dine's, 97. Hypsometrical Apparatus, page 92. Hooker's Pocket, 133. Improved Pocket Registering, 132. Iceland Spar, 1074. Ice-making Machine, Patent, pages 507, 508. Image Plates, 2441. Improved Chronograph, 1189. Incandescent Lamps, 2755. Miniature, 2769. Inclined Plane, Electrical, 2468. Inclined Plane Model, 3025, 3049*. Inclined Plane and Double Cone, 3032. Inclinometer (see Clinometer), page 299. Indicating Signal Bell, page 460. Indicator to Eye Piece, 937. Indicator Steam Engine, and Papers for ditto, page 198. Induction Tube, with Coil of wire, 2698*. Coil, apparatus to illustrate, 2706. Coils,f or Mining or MilitaryService, page 463. Coils, Ruhmkorff's, page 451. Callan's, 2705. Inductorium, 2737. Inertia Apparatus, 3028. Inferential Photometer, Lowe's, 3085. Inhalers, glass, 2008. Injecting Syringe, 1009. Injector, Giffard's Model of, 2948. Instructions for Colouring Lantern Slides^see Negretti and Zambra's Lantern Manual). Instrument for Cutting Thin Glass, 1005. Instruments, Mathematical Drawing, pages 330 to 343. Instrument to count Seconds, 3305, 1189. Insulated Stands, for Electric and Galvanic experiments, 2430. Stool, 2428. Wire, 2717, 2811. or Isolated Thermometers, 304. Intermitting Springs, apparatus to explain, 2920. Invalid's Portable Alarm, 2804. Inversor, Dr. G. Bird's, 2700. Iron Spheres, for freezing water, 2529. Ivory Pocket Rules, page 340. James's, Col. Sir H., Square Rain Gauge, 116. Jars, Air, page 373. Deflagrating, 1993. Dessicating, 1965. for Fountain Experiment, 2905. Gas, 1993, page 375. Glass, for Coating, 2498. Leyden, 2393. Medical, 2395. with movable coatings, 2396. Lixiviating, 2012. Mixing, 2027. Johnson's Metallic Thermometer, 406. Jordan's Sunshine Recorder, 76. Kaleidophone, Wheatstone's, 3067. Kaleidoscope for Lantern, 1822. Kaleidoscopes, 746. Kater's Compass, 1166. 581 NEGRETTI AND ZAMBEA, HOLBOEN VIADUCT, E.G., Keene's Plate Box, supplied To Order. Kellner's Orthoscopic Eye Pieces, ditto. Kerr's Gas Tubes, 2001. Kew Marine Barometer, 15, page 11. King's Self-registering Barometer, 26. King's College Set of Drawing Instruments, 1482. Kingsley's Illuminator, 947. Kinnersley's Electro Thermometer, 2423. Knife, Valentine's Dissecting, 980. Labels, Chemical, 2201. Laboratory Barometer, 13. Portable, pages 409, 411. Lactometer, pages 185, 186. Dr. Hassall's, 495. Tubes, or Cream Test, 485. Ladles, 2260. Lamp, Argand, Chemical. 2261 to 2263. Spirit, 2269. Brass Spirit, 2267. Davy's Safety, 2264, 2993. Electric, 2558, page 438. for Microscopes, for mounting, &c. page 271. Gas, Bunsen's, for Blowpipe, 2266. Glass Blowers', 2178. Glasses, Oxydating, 1790. Hydrogen, Self-acting, 2270. Oil, 2261, 2263. Ships', Starboard and Port, page 323. Anchor, page 323. Submarine, 3126, page 505. Duboscq's, 2559. Miners', 2993. Lamps, Photographic, page 538. for Magnesium Light, 3233. Ships', Binnacle and various, page 326. Tricolor or Steering, 1389. with Movable Lenses, page 322. Engine Boom, &c., page 322. Ships', Masthead, page 323. Spirit, Glass, 2078. Lanterns and Lamps, Dark, 3230. for Ghost Effect, made to order (see Lantern Manual). n for Night Signals, 1736. Magic and Phantasmagoria, page 351. Paraffin, 965. Phantasmagoria, fitted with Oxy- calcium and Oxy-hydrogen Light, pages 358, 359. Phantasmagoria with Microscope, 1746. Lantern Microscope, 1752, page 352. Land Chains, page 301. Lapidary's Grinding Apparatus, To Order. Laryngoscope, 3092. Lean's Circumferenter, 1155. Leather Cases for Lenses and Cameras, To Order. for Portraits, &c., To Order. for Telescopes, and Kace Glasses, To Order. Leather, Gilt and Silvered, strips of, 2508. Leathers for cleaning, 3295. Leclanche's Battery, 2554. Lenses, Achromatic, for Microscopes, page 268. for Telescopes, page 254. Carte de Visite, page 517. Coddington, 708. Concave, 727. Compound, for Portraits, page 517. Condensing, 940, 941. Cylindrical, 732. Dallmeyer's, page 524. Magnifying, page 223. Multiplying, 722. Photographic, pages 517 to 527. Rock Crystal, page 240. Ross's, 526. Print, page 221. Sets of, to illustrate Optics, 744. Stanhope, 708. Stereoscopic Combination, page 524. ,. Voigtlander's Vienna, Supplied to Order. Pocket, various, pages 223. 224. Rectilinear Stereo, page 525. Steinheil's, page 518. Wide Angle Landscape, pages 521 to 525. Leslie's Hygrometer, 84. ./Ethrioscope, 62. Apparatus for Freezing water, 2887*. Pyroscope, 2982. Cubes, or Radiator, 2950, 2981. Differential Thermometer, 2952. Letheby's Photometer, 3079. Levelling or Developing Stands, 3234. Staves, page 302. Level Tubes, Spirit, 1144. American Universal, 1147. Staves, Papers for, 1231. Levels, Drainage, 1132 to 1136. Dumpy, or Gravatt's, 1119 to 1126. Hand, page 288. Circular, 1148. Standard, 1130. Y, 1127 to 1130. 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 585 Levels, Ordnance Pattern, 1130. Lever Sliders for Magic Lantern, 1812. Levers, model, sets of, 3022, 3023. Leyden Jars, 2393. Experimental, 2402. Jars, Medical, 2395. Lichtenburg's Figures, Apparatus for producing, 2489. Lieberkuhu or Cup Reflector, 949. Liebig's Condensers, 2211. Gas Absorber, 2000. ., Potash Apparatus, 2137. Double Neck Eetort, 2013. Life Boat Station Barometer, page 143. Light, Decomposition of, Model to explain, 718. Light, Electric, page 437. Lightning Conductors or Rods described, pages 127 to 129. Lime Cylinders and Balls, 1795. Linen and Cloth Provers, 697. Link Staff, 1236. Liquid Plate Cleaning, 3395. Jet, 4015, 3320*. Lithographic Pens, page 336. Live Box, or Animalculse Cage. 986. Lixiviating Jars, 2012. Loadstone, 2642. Locomotives, Models of, page 489. Lockets, gold and plated, To Order. Log Glasses, 1402. Massey's Patent, T. Walker's ditto Harpoon, A. Walker's Liverpool Ship, Walker's Cherub Taffrail Long's Patent Wine and Spirit Analyser, 549. Long Range Barometers, Negretti& Zam bra's, pages 14 to 20. Glycerine, page 18. McNeild's, page 16. Howson's, page 15. King , page 20. Water, page 17. Look-out Glasses, 846. Binocular, 791 to 797. Lovi's Beads, see Glasgow Beads, Lucernal Microscope, 1752. Lungs, Glass, 2895. Machines, Electrical, pages 412 to 427. Soda Water, page 504. Counting, page 200, 2827. ,, Diving, page 505.1 Ice Making, page 507. Galvanic, Magnetic and Medical, pages 412 to 466. in > f Pages dp, (324, 325, Machines, Weighing, Duckham's Patent, 592. Magazine Cases of Drawing Instruments, 1486. or Revolving Stereoscopes, 781. Magdeburg Hemispheres, 2872. Magic Lanterns, page 351. Manual, page 350. Picture, 2427. Stereoscope, page 230. Maltsters' Rules, page 346. [66, 67. Magnaghi's Deep Sea Thermometers, pages Magnesium Wire, 1797. Magnesium Lamps, 1618. Magnetic Counters, page 467. Needles, 2648. Oxide of Iron, 2642. Toys, 2683. Magneto- Electric Exploder, for Mining or Military Service, page 463. Machines, Clark's, 709. Medical, page 459. Magnetograph, Self-Recording, page 130. Magnets, page 441. Induced or Soft Iron, 2664. Natural or Loadstone, 2642. Terrestrial Rotating, 2691. Bar, 2645. Horse Shoe, 2643. on Brass Foot, 2685. Compound, 2644. Magnetometer (Sturgeon's) 2693. Magnetometer, Unifilar, Kew Pattern, pages 131, 513. Magnifiers, Pocket, Watchmakers' and Engravers', page 223. Magnifying Glasses, Mineralogical, 702, 703. or Print Lenses, 686. Barometer Range, page 14. Malt Gauging Rods, pages 345, 346. Malt Kiln do., page 346. Thermometers, 289. Rods or Sticks, 1651. Receivers, 1683. House Couch Rod, 1685. Steel Cistern ditto, 1684. Tapes, 1686. Mantel or Drawing Room Thermometer, page 156. Map Meter, or Opisometer, 1279, 1280. Maps, various, Supplied to Order. Marcet's Apparatus, 2946. Marine Vacuum Gauges, pages 196, 207. Hydrometers, pages 188, 183. Thermometers, 374, 362, 372, and page 188. Barometers, 15 to 18, page 145 Binoculars, page 237. 586 NEGEETTI AND ZAMBEA, HOLBORN VIADUCT, E.G., Marine Telescopes, page 244. Clinometer, 1438, 1439. Clinometer or Inclinometer, 1438, 1439. Marquoise Scales, 1598 to 1601. Marryat's Code of Signals, 842. Marsh's Arsenic Apparatus, 2139. Vibrating Wire, 2688. Martin's Microscopes, 891. Mash Tun Thermometers, 286. Masks, Wire, 2273*. Mason's Hygrometer, page 73. Massey's Patent Log, 1394. Sounding Machine, 1396. Mast Head Lamps and Compass, page 323, 1428, 1388. Materials, Drawing, page 343. &c., for making Uxy-hydrogen Gas, page 363. for Electrotype process, page 442. Mathematical Drawing Instruments, pages 330 to 338. Curves, 1629. Mats for portrait cases, embossed German or American, supplied To Order. Mareographe or Tide Guage, Sir W. Thom- son's, page 122, 516. Marine Maximum Thermometer, Negretti and Zambra's Patent, 59. Marriotte's Apparatus, page 476. Maximum Thermometers, see Thermometers. Maynooth Galvanic Batteries, 2544. Measurer, Dupuis', procured To Order. Measures, Comparative Tables of English and Foreign (see Appendix). French, 1217. Spanish, 1222, 1217. Cubic Inch, page 558. Graduated, pages 381, 379. Measuring and Weighing Machine, 3090. Altitudes, page 26. Instrument, Morriss', 1281, 1282. Chain, Gunter's, 1207. Standard, 1211. Tapes, page 302. Ordnance, page 302. Rods page 303. Scales, page 304. Mechanical Lantern Sliders andEfects,pages 364 to 368. Mechanical Powers, model apparatus of, pages 491 to 496. Medallions, Plaster of Paris, 2641. Medical Apparatus, &c., page 498. Electrical Directors, 2400. Galvanic Apparatus.pages 455 to 459. Medical Leyden Jars, 2395. Magneto-Electric Machines, 2788. Thermometers pages 160 to 163. Induction Coil, Portable, 2782. Electricity, its use, page 458. Melloni's Thermo-Electric Pile, 2725. Melting Tongs, 2280, 2209. Mercurial Trough, Porcelain, 2030. Iron, 2276. Meter, Experimental Gas, 3081. Meter Chains, 1210. Metal Ball and Ring, for expansion experiment, 2962. Bar, Compound, 2961. Foils and Wires, for combustion, 2353. Bar and Gauge, 2961. Metallic Barometers, Bourdon's, To Order. Thermometer, Brequet's 2965. Immisch's, 3101. Vessel for Radiation experiment, 2978. Meteorograph, Van Rysselberghe's, page 131. Meteorological Instruments, Negrettl and Zambra's Five Guinea Set, page 126. Meteorological Instruments, Negretti and Zambra's Portable Set, 123. Standard, page 1 to 132. ,. Publications, 133. Instruments, Estimates for Sets of, pages 124, 125. Meters, Current, 1190, 2945. Meter, Portable Air, 140, page 99. Metford's Scales, 1635. Metre Rules, Pocket, page 347. Mica for Lockets, &c., To Order. Microphone, see page 494. Micrometer, Annular, 879. Double Image, 878. Eye-Piece, for Microscope, 34. for Microscope Stage, 954f. on Glass, for Telescope, 1341. Position, 879. Micro-Photographs, Apparatus for, 2887. ' Spectroscope, 929. Microscopes, "Achromatic, pages 256 to 275. Beetle or Insect, 694. Binocular, 915 to 924. Botanical, 696. Cloth, 697. Compound, 887. Gould's, To Order. Martin's, 891. Collectors', Pocket, 997. Darwin's, To Order. Dissecting, 886, 892. Educational, page 258. 45, CORNH1LL, E.G., AND 122, REGENT STEEET, W., LONDON. Microscopes, Flower, 691. Gardeners', 692. Magic Lantern, 1752. Students', pages 258, 259. Oxy-hydrogen, 1096, page 282. Seed, 693. Single Botanic or Dissecting, page 256. Brewers, page 261. Microscopic Air Pump, for mounting, 1008. Cabinets, 1040. Copying Camera, made To Order. Dissecting Instruments, 983. Fishing Tubes, 1001. Forceps, 970. Glass Rings and Cells, 99). Microscopic Glass Slides, 993. Glass, thin, 993, 994. Gold Size Cells, apparatus for, 1006. Injecting Syringe, 1009. Lamps, Argand Oil, Paraffin, &c. page 271. Materials, page 273, 274. Mounting Papers, 996. Object Boxes, 1043, 1047. Mounting Lamp, 964.* Object Lenses, page 268. Objects, pages 274, 275. Section cutters, 1007. Stage Plates, 992. Tables, 1048. Test Objects, 1032. Tubes for Collecting, 1001. Camera Lucida, 960. Midshipman's Telescope, 840. Military Drawing Scales, 1589, 1594. Pocket Telescopes, page 243. Telescopes, N. and Z.'a improved, 828, 829. Reconnoitring Binocular Glasses, 796, page 236. Theodolites, page 284. Telegraph, pages 463, 467. Milner's Wire Gauge, 1723. Mineral Holder for Microscope, 973, 981. Mining Theodolite, 1149. Mineralogical Cabinets, page 503. Miner's Barometer, 175. Miners' Aneroid Barometers, 176. Compass, 1157. Dials, page 290. Lamps 2993. Miniature Cases and Frames, To Order. Minim Measures, 2018. Minute Glasses, 1405. Mirrors, Parallel, made To Order. Mirrors, Black, 715. Reflecting, 713. ,, Concave and Convex, 713. Cylindrical and Distorting, 733. Conical, 734. Multiplying, 714. Dentists', 3111. Mitscherlich's Potash Apparatus, 2138. Mixing Jars, 2027. Model Archimedes' Screw, 2929. Apparatus for Submarine Explosions, 2808. Model, Barker's Mill, 2928. Bramah's Hydrostatic Press, 2940. Breast Wheel, 2943. Canal Lock and Sluice, 2944. Model Capstan, 3049. Centrifugal Pump, Appold's, 2927. Diving Bell, 2710. Electro -Motive, 2710 to 2713. Force Pump, 2882. , Geometrical, 3050. Hero's Engine, 2997. Lifting & Force Pumps, 2881, 2882. Locomotives, page 489. Marine Steam Engines, 1313. Mongolfier's Water Ram, 2931. of various Steam Engines, pages 489 to 490. Overshot Wheel, 2942. Undershot Wheel, 2941. Perkins' Steam Gun, 3016. Railway Trains and Railroad, 3011. Sawing, rolling, and grinding mills &c., 3000. Sectional, of High and Low pres- sure Steam Engines, 3017. Steam Boats, 3015. Steelyard, 3048. Model Telegraphs and Signal Bells, 2714, 2715. of the Eye, 745. to explain formation of Screw and Nut, 3026. to illustrate properties of an Arch, 3046. Toothed Wheels, 3047. Water Pump, 2880. Fire Engine, 2884. Steam ditto, 3012. Hero's Fountain, 2930. Models to illustrate Optics, page 225. Acoustics, page 494. Models, various, to explain and illustrate the laws of Mechanics and Dynamics, page 491. 588 Mohr's Burettes, 2211, 2212. Monochord, 3062. Moon, Stereoscopic Views of, To Order. Morocco Cases and Trays supplied To Order. Mortars and Pestles, Agate, 2021. Berlin Porcelain, 2022. Glass, 2024. Iron and Brass, 2278.* Steel, 2279. Wedgwood Ware, 2023. Morse Telegraph Instruments, 3144. Mounting Apparatus, Microscopic, 984. Lamps, ditto, 964*. Mountain Barometers (see Barometers, page 11.) Muffles, 2026. Multiplying Lenses, 722. Musical Flames, Apparatus for producing, 2136. Napier Pocket Compasses, 1539. Natural Magnets, 2642. Nautical Almanacks and other books, sup- plied To Order. Instruments, page 308, Navigation Scales, 1593 to 1597. Navy Code of Signals, 843. Sextants, or Cadet's, 1292, 1293. Telescopes, page 245. Needle Holder, 1528. Needles, Stands for, 2650. Astatic, 2651. Deflecting, Oersted's experiment, 2661. Dipping, 2660. Magnetic, 2648. Negretti and Zambra's Standard Meteorological Instruments, and Improvements, pages 1 to 133. Negretti and Zambra's Military Binocular, 796, 790*, Newman's Colours and Varnishes, Photographic, page 344. Mountain Barometer, 12. ,, Tide Gauge, 174, page 120. Nicholson's Gravimeter, page 190. Nichol's Prisms, 1064, 1065. Night Compasses, 1341. Glasses, Captains', Pilots', or Military, page 798, 851. Telescopes, Inverting, 835. Nitrous Oxide Gas Apparatus, 3116. Nippers, or Cutting Pliers, 2281. Nitrate of Silver, page 549. Bath, page 3319. Nitrogen Apparatus, Ure's, 2143. Nitrogen Apparatus, Horsford's, 2145. Will and Varrentrap's, 2144. Object Glasses for Telescopes, page 254. Object Glasses for Microscopes, page 268. Objects for Microscope, page 274. Oxy-hydrogen Microscope, page 274. Occhiombra, 3115. Oersted's Apparatus, 2661. Off-set Scales for Plotting, page 339. Oil Bath, 2115. Oil for Ships' Lamps To Order. Oil Hods, 1678. Oleometer, 473, page 184. Omnimeter, Eckhold's, 1142. Opaque Microscope, 1773, page 361. Opera Glasses, Achromatic, Binocular, page 234 to 240. Bijou, 806. Single or Monocular, 806. Sydenham, 806. Tom Thumb, 806. Aluminium, page 238. Duchesse, or Empress, 805. Ornamental and Fancy mountings, 803. Oval or Elliptic, To Order. Twelve-lens, see pages 236, 237. with Adjusting Centres, 794. Opera Glass, Rock Crystal, page 808. Opisometer, 1279. Ophthalmoscope, 3098. Optical Instruments, and Spectacles, page 212. Optical Square, 1164. Optics, Models to illustrate, 744. Optometer, 3112. Ordnance Measuring Rods and Scales, page 303, Pattern set of Surveyors' and Engineers'Instruments,page307. Organic Analysis Apparatus, page 394. Organ Bellows, 3068. Ormolu Frames, To Order. Orreries, page 328. Electrical, 2465. Orthoscopic Lenses, To Order. Orometer, 1180. Osier's Anemometer and Rain Gauge, page 107. Oscillating Steam Engines, models of, 3003. Overshot Wheel, model of, 9442. Oxy-calcium Light (see Dissolving Views), page 358. Lamp, 1775. Oxygen Gas Retort, 1778, 1779. 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 589 Hanitariums, 1453. Oxygen Gas Retort, Glass, 1992. Oxy-calcium Gas Jet, 1776. Oxygen Gas Mixture, 1794. Oxy-hydrogen Gas Apparatus, page 362. ,, Burners, 1777. Oxy- Hydrogen Light (see Dissolving Views), page 319. Microscope, page 282, 1096. Ozone Box, 159. Cage, Sir James Clark's, 160. Apparatus for Testing, described, &c., page 113. Tube, Siemen's, 154. Tube, Will's 30/- Case, Lowe's, 161. Ozonometer, Moffat's, 156. Schonbien's, 158. The use of these tests now given up. Pancratic Eye Tubes, Kitchener's, 825. Pantometre, 1162. Pantoscopic Spectacles, page 214. Paper, Filter, pages 401, 544. Mounts for Microscopic Objects, 996- Photographic, page 544, 545. Papers for Station or Levelling Staves, 1231. Albumenized page 545. for Steam Indicators. Forrustecher's, page 545. Test, 2336. Tracing, 1644. Paper Weights, 1648. Paradox, Hydrostatic, 2910. Parabolic Reflectors, pages 404. 487, Paraffin or Petroleum Hydrometers, page 177. Testing Apparatus, page 170. Thermometers, 391*. Lamps for Microscope, page 271. Parallel Rules, Rolling, page 339. Parchment Paper, for use with Dialyser, 2149. Parting Glasses, 2029. Passe Partout, Supplied To Order. Stereoscopic, ditto-. Passometer or step Measure, 1188. Patent Stereoscopes, 771. Pedestal Globes, page 328. Pedometer, 1187. Pencil Bows, 150 . Pencils, small, for Drawing Instruments, 1640. Pens, Bows, 1509. Drawing Page, 336. Dotting, 1525. Road, 1526. Ruling, 1519. Pen Machine, 1646.J [137. Pendulum Anemometer, Negretli & Zambra's, Pendulum Wheel PrismaticClinometer, 1170* Pentagraphs, 1266. Pepys' Gas Holder, 2066. Pelorus, Friend's, 1429. Pitchometer, 1441. Piche's Evaporometer, 140, page 139. Pickets, 1728. Perambulators, or Road Measures, 1185. Percolator Glass, 2040. Percy's Apparatus for Alkalies, 2142. Periscopic Spectacles, 620. Perlivision Spectacles, 632. Perkin's Steam Gun, 3016. Perspectives, page 242. Phantascope, 757. Phantasmagoria Lanterns, page 351. Pese-Acide (see Baume's Hydrometer, or Ar^ometre de Baum<) Esprit ditto ditto, page 177. Sirop ditto ditte, page 177. Phenomena of Heat, page 481. Photographic Apparatus, sets of, page 553. Brushes, 3306. Cameras, pages 528 to 533. Chemicals, pages 550 to 552. Colouring Materials and Colours, page 344. Glass, page 544. Lenses, pages 517 to 527. Papers, pages 545 and 544. Slides for Magic Lanterns, &c., page 369. Statues for do., pages 369 and 370, Tents, pages 534, 535. Hydrometer, 3242. Developing Box, page 534. Photometers, for Coal Gas Testing, Bunsen's, Letheby's, Evans', King's Sabine's 3305* Wheatstone's, Lowe's, 750, page 497. Physicians' Thermometers, page 160. Pile, De Luc's, 2415. Melloni's, 2725. Zamboni's, 2416 Volta's, 2513. Pillar Compasses, page 337. Pilots' Binocular Night Glasses, page 237. Telescopes, page 244, 834. Pincettes (see Forceps). Pince-Nez, page 216. Pins, Drawing, 1637. Pipettes, pages 385, 386. Graduated 2035., Pistol, Electrical, 2478. Pith Balls, 2444*. Ball Stand, 2443. Figures, Electrical, 2442. 590 NEGRETTI AND ZAMB11A, HOLBOEN VIADUCT, B.C., Planimeter, Amslers, 1260. Integrator, Amslers, 1261. Plate Boxes, page 543. Cleaner, 3258. Cleaning Liquid, 3395. Fiaraesfor Cameras, To Order. Phonoscope, 3144. Photometer, Sabine's, 3305*. Plane Table, 1710. Piezometer, 3148. Plate Boxes, Holders, Pneumatic, page 543. Plated Lockets, supplied To Order. Platinum and Silver Chain, for Galvanic experiments, 2568. Goods, 2282 to 2285. Plates, Vignette, 3288. Platinized Silver, 2580. Plotting Scales, 1573. Pluviometers, pages 82 to 89. Pneumatic Apparatus, sets of, To Order. Plate Holders, 3254. Trough, Berlin Porcelain, 2031. Metal, 2288. Drop Tubes, 2033. Pocket Anemometer, pages 99 to 101. Alt Azimuth Instrument, 1202. Compasses, Pillar, &c., page 337. ., Condenser, 2859. Galvanic Coil, 2782. Hygrometer, 96. Hydrometers, page 453. Hypsometric Apparatus, page 94 (Dr. Hooker's). Rain Gauge, 115. Saccharometers, 452. Pocket or Portable Satchel Camera, pages 533 to 527. Pocket Dividers, 1538. Barometers, pages 23 to 26, and 29. Compasses, Mariners', page 314. Napier's, 1539. Globes, page 328. Magnifiers, page 223. Measuring Tapes, Spring, page 302. Rules, 339, and page 347. Sets of Drawing Instruments,page 334. Sextants, page 310. Spectroscopes, 1077. Telescopes, page 242. Thermometers, page 155. Polariscope, Biot's Black Mirror, 1052. Duboscq's Soleil's, 1055. for Liquids, 1055. Laurent's New Shadow Saccharometer, 1056. . Eolipile for use with above, 1058. Polaiiscope, Le Count's Mirror, To Order. Malus's, 1051. for Sugar, 1055. Oxy-hydrogen, page 282. Reflecting, 1051. Tourmaline, 1050, 1054. Woodward's Table, 1053. Field's Differential Ratio Micro, 928. Polarising Apparatus, for Microscopes, 956 to 959. Crystals and various Objects, pages 297, 280. Eye Piece, 1063. Polemiscope, 756. Polishing Buffs, Made to Order. Polyorama, 758. Polyps Trough, 985. Porous Cells, 2639. Portable Forge, page 401 and 402. Laboratories, page 409. ., Steam Engines and Boilers, page 211. Stills, page 406. Electrical Alarm, pages 460 to 465. Frames for Lantern Screens, 1793. Air Meter, for Mines, &c., page 99. Porcelain Retorts, 2051. Dipping Baths and Dishes, pages 542 and 453. Pourettes, 2041. Port Lamp, Ship's, page 323. Portrait Lenses, page 517. Show Frame, Made to Order. Position Micrometer, 879. Positive and Negative Electricity explained, page 449. Potash Apparatus, Liebig's, 2137. Mitscherlich's, 2158. Pipettes, 2037. Pouring Glasses, 3239, 3109. Bottles, 3237. Powder House, 2473. Praximoscope, 755. Precipitating Glasses, 2012, 2029. Philips's, 2099, 2027. Pressure Boards, 1785. Frames, page 546. Gauge, King's Gas, 3083. Gauges, Various, Steam, &c., See Gauges. Presselles or Pushes for Electric Bells, page 464. Priestley's Thunder House, 2471. Print Lenses, page 222. Machines, Diagonal, 729. 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 591 Prismatic Compasses, page 293. Case and Strap for ditto, 1171. Stand for ditto, 1175. Improved, or Alt- Azimuth, 1170*. Compass, Ordnance Pattern, page 307. Telescopic, 1177. Hutchinson's, 1174, Kater's, 1166. Azimuth Compass, 1377. Snow Harris's, Transparent, 1386. (Compass) Plane circular, 1166. Kitchie's Liquid, page 321, 322. Prism, Rectangular, 717. Bisulphide of Carbon, 1087. ,. Quartz. Made to Order. Prisms, Compound, 719. Deck, To Order. Prisms, Double Image, 1065. Glaas, 717, 1086. Hollow, 721. Nichol's Double Image, 1065. Prisms, Nichol's Single Image, 1064. Proportional Callipers, 1551, 1701. Compasses, 1534. Protractors, page 340, 341. Brass Circular, 1610. Ivory, 1585. Brass Semicircle, 1606. Card, 1605. Horn, 1604. Red line, Ivory, 1589. Psychrometer, page 95. Pulleys, system of, 3024. Pulse Tubes, 2044. Pumps, Air, single and double barrel, pages 468 to 471. Centrifugal, 2927. Condensing, 2852. Exhausting, 2850. Force and Lift, models of, page 472. Pump, Triple Cylinder, 3127. Condensing, for Diving Apparatus, page 506. Tate's, 2847. Sprengel's, 2849. Calletet's Compression, 3149. Pumps, Air and Water Compression, 3152. Purifier, Gas, 1781. Pyrheliometer (Pouillett's), 61. Pyrometers, pages 203, 204, 484. Pyrometer, Helio, 60. Pyroscopes, Leslie's, 2982. Quadrants, page 311. Quadrants, Metal, 1320. of Altitude, 1452. Quadrant Electrometer. 24 13. and Sextant Glasses, page 310. Quain's Stethometer, 3110. Race Glasses, Binocular, pages 233 to 240. Radii Curves, 1631. Radiator, Leslie's, 2980. Radiometer, Crooke's, page 276. Railroad and Railway Trains, Models, 3008. Eye Preservers, page 219. Regular and Railway Curves, page 343. Rain Gauges, Admiral FitzRoy's, 114. Glaisher's, 110. Howard's, 108. Pedestal, 112, 113. Symons's Improved, 94. Snowdon, 118. Storm, 121. Square (Col. Sir H. James), 116. Registering (Crossley's), 120. Pocket, 115. Osier's Registering, page 107. instructions for use of, 82. Meteorological Office, 117. Marine, 124. Water Works or Mountain, page 551. Bentley's Snow Melting, 123. ,, described, pages 81 to 89. Rain Fall, Tables of, page 81. Statistics of, page 81. Charts, page 133. Rainey's Light Modifier, 951. Ranging Poles, 1728. Reade's Condenser, 948. Reading Glasses, page 222. Receivers, page 475, 476. Cooper's Gas, 1946. Tube, 2056. V and U shape, 2063, 2064. Glass and Air Pumps, page 475. Receivers with 3 necks, 2062. Re-composition of Water, apparatus for, 2131. of Light, 718. Reconnoitring Binocular Glasses, N. ar.d Z's Improvement, page 240, 241. Telescopes, 825. Rectangular Battery Troughs, 2574. Wire Frames, 2721. Prism, 717, Reduction Tubes, 2046. Reflecting Circles, 1589, page 308. Prism, 953*. 592 NEGEETTI AND ZA3IBRA, HOLBOEN VIADUCT, E.G., Reflecting Stereoscopes, Wheatstone's, To Order. ., Telescopes, page 255. Reflector, Side Speculum, 954. Reflectors, 2973. Parabolic, 2977. Registering Thermometers (see Ther- mometers). Registering Barometers (see Barometers). Regnault's Condenser Hygrometer, 87, 88. Respiration Glass, see Lungs' ditto, 2895. Rests for the Head, page 537. Retorts, Berlin Ware, 2050. Clark's, with receiver, 2055. Earthenware, 2048. Glass, for Oxygen Gas, 2055. German Glass, page 2052. Liebig's, 2013. Lead, 2296. Platinum, To Order. Stands, page 405. Stoneware, 2049. Tube, 2055, 2053. Oxygen, Copper, 2249. Iron, 2250. Reversing or Copying Frames, page 546. Revolving or Magazine Stereoscopes, page 232. Regulation Sets of Instruments for Naval Cadets, and the Royal Engineers, page 306. Rheometer, page 454. Rheostat, Wheatstone's, 2768. Rheotome, see Contact Breaker. Rhombs of Iceland Spar, 1074. Richard's Steam Engine Indicator, page 198. Ritchie's Rotating Electro- Magnet, 2677. Road Measures or Perambulators, 1185. Road Pens, 1526. Robinson's Anemometers, page 105. Robert's Hydrometer, 469. Rock Crystal Lens Opera, Field and Race Glasses, page 240. Rods, Dipping, Steel Cistern, Gauging, Spile, &c., pages 345 to 347. Surveyor's Timber, 1703. Bung or Fat Gauge, 1676. Lightning, pages 127, 128, 129. Spile, 1668. Oil, 1678. Rupert's Drops, per dozen, 2s. 6d. Rods, Dipping, Gauging, Ullaging, Malt, Diagonal, &c., pages 345, 346. Rolling Machines, page 549. Rope Gauge, 1705. Ross's Centreing Glass, 936. Rotating Disc, Sturgeon's, 2692. Wheel, Stellar, Barlow's, 2696. Wire Apparatus, for exhibiting, 2689. Coil, 2698. Rotometer, pages 201, 202. Roof Horizon, see No. 1323. Ruhmkorff ' s Induction Coils, page 451. Rules, Brewers', Distillers', and Maltsters', page 345 to 347. Gauging, sets of, 1662. Carpenters' and Engineers', page 345. Folding Pocket, page 347. Gunners, 1602, page 348. Gun and Shot, 1238. Parallel, page 304. Reducing, 1671, 338, 339. Standard, pages, 347, 348. Ruling or Drawing Pens, page 336. Sabine's Photometer, 3305*. Saccharometer, Baume's, 422. Brass, 423. Brewers' Glass, 436 to 439. Standard, 439. Saccharometers, Glass and Metal, as supplied by N. & Z. to the Excise, pages 181, 182. Saccharometer, Combined Hydrometer, 446. Thermometer, 447. Can, for testing, 448. Jars, Glass, 438. Gilt Metal, 400 to 442. Safety Funnels, page 389. Salinometer, page 188. How's, 521. Saunder's, 522. Gamble's, 523. Trial Pots, 518. Thermometers, 517. Satchel or Pocket Camera, page 533. Salt Water Thermometer, 40, 403. Salt Water Beads or Bubbles, 525. Sand Baths, Copper, 2301. Saussure's Electroscope, 2421. Hygrometer, 83. Saturometre, 417. Scales, Bullion, 2305. Scales and Weights, Chemical (see Balances). for Counter, &c., 2303, 2304. for Photography, 3247. for Weighing Gold or Diamonds, 2302*. Drawing, various, pages 303. 307, 338 to 343. Architects', 1565. Gunter's, 1595. 45, CORNHILL, B.C., AND 122, REGENT STREET, W., LONDON. 593 Scales, Marquoise, 1598. Metford's, 1635. Military, 1594. Navigation, 1593. Ordnance Pattern, page 307. Plotting or Chain, 1571 to 1577. Schaeffer's Pressure and Vacuum Gauges, page 205. Scheeffer's Hydrometers (see Hydrometers). School Sets of Drawing Instruments, page 330, and No. 1553. Schuster's Alkalimeter, 1906. Scioptocon, page 347. Scribing Iron, 1704. Screens for Magic Lantern and Dissolving View apparatus, 1792. Superheated Steam Thermometers, 372. Sea-coast or Life Boat Station Barometer, page 143. Sea Level, 32, page 36. Sea Water, Density of, page 183. ,, Freezing point of, page 195. Temperature of, at great Depths, page 65. Pressure of, at great Depths, page 65. Sealing-wax Cylinders, Electrical, 2488. Seconds, Instrument to count, 3305. Section Cutters, 1007. for Muscular Fibre, Tissues, &c , To Order. Sectional Models of various Engines, 3018. Sections, Microscopic, page 275. Sector Scales, 1585, 1591. Seed Microscopes, 693. Selenite Designs, 1068. Plates, 1067. Self-Kecording Anemometers, pages 106 to 111. Aneroids, pages 27, 28. Sensitizing or Developing Dishes, page 542. Separating Funnels, 2071. Receiver, 2072. Set Squares, page 342. Sets of Chemical Apparatus, page 410. for Analysis of Soils, 2371. Electrical Apparatus, 2379 to 2385. Electro-Magnetic Apparatus, 2720. Galvanic Apparatus, 2589. Levers and Pulleys, page 491. Optical Models, page 225. ., Lanterns and Slides, Dissolving View Apparatus, pages 351, 352 to 374. Pneumatic Apparatus, To Order. Lenses, 744. Sets of Spring Bows, page 335. Photographic Apparatus, page 553. Drawing Instruments, pages 330 to 343. Small, 1553. Gauging Instruments, page 345. Induction Coil Apparatus, page 451. Meteorological Instruments, Estimates for, pages 124. 125. Ordnance Pattern Surveying Instruments, Rods and Scales. pages 303, 307. Sextants, pages 308, 309. Pocket, 1302, 1304. Glasses, Telescopes, and Magnifiers, page 310. Shadbolt's Parabolic Condenser, 942. Shears, Cutting, 2311. Ship Curves, 1633. Ships' Binnacles, page 326. Board of Trade Regulation Starboard and Port Lamps, page 323. Chronometers, supplied To Order. Logs, pages 324, 325. Log Dial, Admiral Bullock's, supplied To Order. Barometers, pages 136 to 146. Thermometer Screen, page 79. Shock handles, 2780. Shooting or Cap Glasses, 675. Shunts for Thomson's Galvanometer, 2708. Sick Room Telegraph, 2804. Side Reflector for Microscope, 954. Siemen's Pyrometer, page 204. Dynamo Electric Machine. page 439. Sieves, 2312. Signal Bell, Electro-Magnetic, pages 449. 4GO to 467. Fog, Key's Patent, 1435. Signals, Marryatt's code of, 842. ., Flags, 1731, and To Order. Navy, 843. Signal Station Telescopes, 854. Sine Compass or Galvanometer, 2675. Singer's Patent Compass, 1341. Single Achromatic Landscape Lenses. page 517. Opera Glasses, 806, page 239. Sike's or Syke's Hydrometers, page 178. Sixe's Thermometer described, page 164. Registering Thermometers, 326 to 336. Signal Lamps, page 323. for Heliostat, 1736. Silver Bottle, &c., 2986. Wire Hooks and Dippers, 3299. Q 2 NEGEETTI AND ZAMBKA, HOLBOKN VIADUCT, E.G., Skeleton Frames, or Passe Partout, To Order. Slides, Astronomical, 1803. Comic, moveable, 1810. Fairy and N ursery Tales, in Sets, 1802. Dioramic for Lanterns, pages 366, 367. for Magic Lanterns, page 351. Geological, 1808. Lever, 1812. Photographic, for Lantern, &c.. pages 3G9 to 372. Eackwork, Mechanical, 1818 to 1829. to exhibit Rolling and Moving waves of the sea, 1825. to illustrate Ancient and Modern History, Conchology, and Botany, To Order. ,, Manners and Customs of the Chinese, page 373. Natural History, 1807. with moveable Shipping, Railways, &c., 1811. Statues, page 369. Sliding Wire and Plate, 2858. Sling Cases for Race Glasses, &c., To Order. for Telescopes, To Order. Slide Rules, proof of Temperature, Compara- tive or Reducing, 1671, page 345. Smeaton's Air Pump, Newman's Improved, page 470. Smee's Galvanic Batteries, 2529, page 430. Optometer, 3112. Snow Gauge?, made To Order. Snow, Harris's Compass, 1386. Soda Water Apparatus, page 504. Soft Iron Magnets, 2664. Sounding Chain and Line, 1732, 1733. Sounding Machines, page 324. Sounding Thermometers, Double Tube Deep Sea, Negretti and Zambra's, page 60 to 67. Sopwith's Station Staff, 1224. Sorby's Micro-Spectroscope, 1027. Solar Radiation Thermometers, page 38. Stand, pages 39, 43. Solar Intensity Apparatus, page 43. see Jordan's Sunshine Recorder. Camera, 3212. Microscope, To Order. Spatulas, 2313. Speaking Trumpets, 1430. Specific Gravity Beads, 524, page 190. Bottles, 2074 to 2077. explained, page 176. Spectacle Cases, 681. Manual, price 6d. Spectacles, Cataract, 624. Clip-nose or folding (Pince-nez), page 216, r 217. Gold and Silver, pages 214, 215. French pattern, 678. Gold, page 214. Forsenic, page 214. Hand Folding, &c., page 218. Horse-shoe, 666. Invisible or Perlivision, 632. Patent Pantoscopic, 619. Periscopic, 620. ThWmoscopic, page 222. Shooting, Hunting or Riding, 675. Silver, 633. Steel, page 213. with Neutral Tint glasses, page 219. the Invention and History of, page 212. Spectra, various instruments for exhibiting, page 225. Spectroscopes Table, 1081 to 1085. Duboscq's, 1081. Pocket, 1077. Spectrum Apparatus, page 282. Speculum Auris, 3095. Speculum Reflectors, 954 and page 500. Spirals, Electrical, 2454. Spirometer, Hutchinson's, 3088. described, page 498. Lowne's Patent, page 499. Spoons, Blowpipe, 2186. Deflagrating, 2218. Glass, 2079. Sportsman, Electrical, 2476. Sprengal's Air Pump, 2849. Spring Bow Pens, Pencils, and Dividers, page 335. Measuring Tapes, page 302. Screw Dividers, 1508. Callipers, 1701. Springs for Steam Indicator, page 200. Specula, Toynbee's, 3094. Spile Rods, 1668, 1669. Spirit Rule, 1671. Level Circular, 1148. Level Tubes, 1144 to 1146. Analyser, Long's Patent, page 193. Lamps, Glass, 2078. Levels, page 288. or Liquid Compass, 1387, 1387*. Sponge Directors, 2780. Squares, Optical, 1164. T, 1618 page 341 and 342. Staff Officers' Glass, page 234. 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 595 Stage Micrometer for Microscope, 954f. Plates, 992. Standard Chains, page 301. Barometers, page 4 to 13. Weights, 2358. Hygrometers, 94. Level, 1130. ., Meteorological Instruments, pages 1 to 131. Ham Gauges, page 83 to 89. ., Thermometers, page 32. Measure, 1211, 1239. ., Surveying Instruments, page 283. Stands, Camera, page 536. Camera Lucida, 737. Crucible, 1939, 2208. ., Developing or Fixing, page 538. Egg, 2438. ., for Aneroid Barometers, page 150. ,, for Azimuth Compasses, 1385*. for Fruit, &c., on Air Pump, 2865. for Magnetic Needles, 2650. for Prismatic Compass, 1172. for Prismatic Azimuth ditto, 1385*. Insulated, for Galvanic or Electrical experiments, 2430, 2407, 2408. .Stands, or Support for Liebig's Condenser, 2212. Pith Ball, 2443. Retort, page 404, 405. Sextant, 1300. Telescope, page 246. Test Tubes, 2340. Thermometer, page 79. Varley's, Telescope, To Order. Standard Spectrum Scale, 1029. Stands, Equatorial Telescope, page 252. Stand. Levelling, page 538. Stand Condenser, 940. Stanhope Lenses, page 224. Star, Electrical, 2432, 2752*. Star Finder, page 254. Starboard Lamps, Ships', page 323. Starlight Compass, 1360. Statues, Photographic, for Lantern, page 369. Station Pointer, 1614. Staves, Levelling or Station, page 302. Levelling, Sopwith's, 1224. , Col. Strange's, 1228. French, 1229. Link, 1236. Steam, Apparatus to illustrate, page 481. Boats, models of, 3015. Steam Engine, Branca's, 2998. De Cau's, 2999. Indicator,Richard's,page 172. Steam Engine Indicators, pages 198, 199. Hero's, model of, 2997. Horizontal, 3005. Oscillating, 3003. Penn's, 3014. Savory's, 2999. Watt's Low Pressure, 3001. ., Watt's High ditto, 3002. Fire Engine, 3012. Steam Engines and Boilers, Portable, page 211. Steam Engine, Horse-power of, explained, page 559. Steam Gauges, pages 205 to 210. Bourdon's, pages 206 to 209. Mercurial, page 174. Schaeffer's, page 205. ,. Fittings, Taps/Whistles, Safety Valves. &c., &c., page 210. Ice Machine, page 507, 508. Pressure Thermometers, page 174. Steatite Gas Burner, Bunsen's, 1092. Steel Spirals, 3065. Measuring Tapes, 1218. Steelyard, model of, 3048. Stage Forceps, 974. Mineral Holder, 973. Steel Straight Edge, 1624. T Squares, 1622. Triangles, 1623. Steering Compasses, page 320. Steering or Telegraph Lamps, (Tricolor) 1389. Stereoscopes, Achromatic, 776. Cabinet, 780. Folding and Book, 784*. Opera Glass adjusting, 776. Patent Cosmoramic, for short sight. page 229. Patent Magic, pages 230, 231. Reflecting, Wheatstone's, To Order. Revolving or Magazine, page 232. Stereoscopic Cabinets and Boxes, page 233. Cameras, page 532. Mounts, To Order. Portrait Lenses, View Lenses, pages 517 to 527. ' Views, coloured, Crystal Palace.&c., on Glass or Paper, pages 232,233. Stethometer, Quain's, 3110. Stills, page 406. Photographic, page 537. Stirrers, glass, 2080. Stirring Rods, 2081. Still Thermometers, 361. Wine, page 193. Working Model, 2316. 2q2 596 NEGEETTI AND ZAMBRA, HOLBOEN VIADUCT, E.G. Still, Stone Ware. 2082. Stone Ware, 2083. Filters, 2084. Stool, Electrical, 2394. Stopcocks, Brass, 2'326. Glass, 2084. Gutta Percha, To Order. Iron, 2328. Storm Compasses, page 320. or Weather Glass, page 147. Straight Edges, 342. Steel, Flexible, 1625. Strophometer, Hearson's, 593. Students' Microscopes, pages 258, 259. Chemical Cabinets, page 410. Sturgeon's Battery, 2522. Magnetometer, 2693. apparatus for igniting Gunpowder, Rotating Disc, 2692. [2474. Semi-Spiral Disc., 2681. Submarine Explosive apparatus, page 463. Lamp, 3126. Suction Tube, 2088. Sugar Pan Vacuum Gauge, 563. ., Thermometer, 367, 415. Sulphuretted Hydrogen Apparatus, 2087. Sulphuric Acid Dish, 2086. Sun Dials, page 313. Globe, 1329. Universal, with Compass, 1350. with Cannon, page 314. Pocket, pages 317, 318. Sunshine Recorder, Goddard's, To Order. Campbell's, page 56. Jordan's, page 57, 59. Super-heated Steam Thermometer, 372. Surgical Instruments, page 498. Surveying Instruments, page 283. Chains, page 301. Surveyor's Cross, page 292. Measuring Rods, pages 302, 303. Scales, page 339. Dial, 1156. Barometers, pages 11, 295. Aneroid Barometers, page 296. Sulphate of Mercury Battery, 2782. Sulphur Test, Letheby's, To Order. Swan, Electric. 2446. Magnetic, 2683. Swedish Filter Paper, 2239. Syke's Hydrometers (see Hydrometers). Sympiesometers, page 146. Syphons, Glass, page 390. Metal, 2329. Negretti & Zambra's, 2094. Syphon Washing Bottle, 2120. Syrene or Siren, 3066. Syringe and Lead Weight, 2860. Condensing, 2851. Exhausting, 2850. Exhausting and Condensing, 2852. Fire, 2859, 2960. Glass, 2095. Injecting, 3122. System of Levers and Pulleys, page 491. Table, Glass Blowers', 2177. Table Globes, page 328. Taffrail Log, Walker's, 1397. Tantalus Cup, 2919. Taper Holder, 2333. Tapes, Measuring, page 301 . Malt or Gauging, 1686. Taps, Steam, Gas, or Guage, page 210. Taylor's Hot Air Bath, 2334. Tates' Air Pumps, page 470. Tachometer, to indicate revolutions per minute. Supplied To Order. Telemeter or Hydroscope, 1202*. Tea Brokers' Time Glasses, 1418. Telegraph Electro- Magnetic Models,page 449. Instruments, Wheatstone's pages 466, 467. Models and Bells, page 461. Telegraph or Steering Lamps (Tricolor), 1389. Telephone and Microphone, 3069. Telescopes, Altitude and Azimuth, page 283. Achromatic Pocket, page 243. Aluminium, 830. Astronomical, pages 247 to 252. Telescopes, Astronomical, with Silvered Glass Specula, page 255. Cases, To Order. Day and Night, 831. Deck, 839. Educational, page 250. Equatorial, page 252. Improved Transit for Determina- tion of Time, page 254. Marine, page 244. Midshipman's, 840. Military, 827. Navy, 836. Negretti and Zambra's Improved Binocular, page 241. Telegraph, 846. " MacLeod " Deer Stalking, 829. Night Erect, 832. Night Inverting, 835. Pilot, 833. Pocket, page 242. Deer Stalking, 828. 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 597 Telescopes, Travellers' Portable, Terrestrial, and Astronomical, 852. Tourists', page 243. Reconnoitreing, 827. Reflecting, for Students, 880. ., Foucault's, 884. Rifle Practice, 846, 854. ., Sea Side, on Table Stand, page 854. for Sextant, 1311. Signal Station, 854. Stands, Portable, see page 246. Target Practice, 846. Transit, page 253. with Compass, 845. Universal, page 247. Telescope Eye Pieces, page 255. Object Glasses, 244. Micrometers, 878. Tellurians, 1453. Temperature, extremes of, pages 34, 35. of the earth, page 172. Tern-plates for Rails, To Order. Tents, Portable Photographic, page 534. Terrestrial Rotating Magnet, 2691. Test Chests, Agricultural, 2371. Chemical, page 409. Toxicological, 2372. Test Glasses, 2098, 2100. Jars for Hydrometers, 450, 512. Lines, Nobert's, To Order. Mixers, 2001. Objects for Microscope, 1032. Papers, 2336. Tubes, 2102. Tube Holders, 2339. ., Tube Brushes, 2338. Stands, 2340. Theodolites, page 284. Everest's, 1114, 1118. Transit, 1102*, 1105. Underground, 1149, Thermo-Electric Apparatus, page 450. Pile, 2725. Thermometers, pages 152 to 175. Air, 360. Alarm or Valve regulating, 357, pages 460, 461. .. Alcohol, 222, see also Minimum Thermometers. ,. Bath, page 159. ,. Beehive, 235, 344. Bent Tube, page 174. Board of Trade, 40, page 33. Boiling point, 131, page 92. Botanical, page 156. Brequet's Metallic, 2965. Thermometers, Immisch's ditto, 3101. Brewers', page 157. with Blind Scales, 280. Gyle Tun, 283. [381. Standard Reference, 282, with Patent Porcelain Scales, 271*. Charts for, page 1S2. Chemical, page 159. [2965. Compound Bar Metallic, 406, Cooking or Culinary, 365. Cup Shape, Bulb, 58. Dairy or Milk, 293. ,, Comparative Standard, 39. ,, Kew Compared ditto, page 125. Confectioners', 351. Brewery yard Registering, 288. Deep Sea Sounding, pages 60 to 67, Negretti and Zambra's Double Tube, 407, page 173. Dentists', 346. Electro, Harris's, 2422. Kinnersley's, 2423. Experimental, page 137. Extremely Sensitive and Delicate, 41, 306. for Gas Testing, page 479, and To Order. for Temperature of the Earth, 43, and page 35. Gridiron Shape, 41, page 33. Hot-air, 368. Hot-blast, 370. Hot-bed, page 157. Insulated or Isolated, 304. Ivory Scale, 244. Johnson's Metallic, 406. Differential, Leslie's, 359, 2952. Improvements of, by N. & Z. page 32. Negretti and Zambra's Horticul- tural Minimum, 324. N. & Z.'s Patent Standard Maximum, 48. N. & Z.'s Patent Solar Radiation, 49. N. & Z.'s ditto in Vacuum, 50. N. & Z.'s ditto ditto, with Mercurial Test Gauge, 52. N. & Z.'s small Maximum and Minimum, 71, 377, page 51. N. & Z.'s Standard Minimum, 63. N. & Z.'s Patent Standard Mercurial Minimum, 68. [p a g e 49. N. & Z.'s Second Patent, ditto, 68*, N. & Z.'s Standard Terrestrial Radiation, 64. 598 NEGRETTI AND ZA.MBRA, HOLBORN VIADUCT, EC., Thermometers, N. & Z.'s do. do., with Link Shape bulb, 65. N. & Z.'s Vertical Solar Radiation, 54. N. & Z.'s Maximum for Mines, Boiling Springs, &c.> 57, 342*, page 171. Add or Subtract, for Milk, 490. Air Shaft, 369. Aquarium, page 159. Boiling Spring Registering, 57. Balloon, 41. ,, Chemical Manufacturers',pages 159, 350. Clinical, pages 160, 500. Cattle plague, 311. ., Disinfecting, 379*. ,, Debate, 263. Drawing room, page 153. _,, Floating, 290. Thermometer, Immisch's, 31.01. Extreme Low Range, for Refrigerating Chambers, 392. Thermometers, Ground or Earth, page 34. Gridiron Bulb, 41. Horticultural, page 164. for Hot Rollers, 378. Hall, page 153. Hay Stack, 355. ,, for recording Hourly Tempera- tures, page 52 to 56. Hydrometer, 382. Incubating, 384. Independent Standard, 38. Mantel, page 156. Malt kiln, 289. Mash tun, 286. Marine, page 173. Mortuary. 379*. ., Minimum, page 45. Mining or Pit, 342*. ' Oven, 342. . Petroleum Testing, 391*. Pocket, or portable, page 155. Pocket, Circular, 240. in Leather Cases, page 155. ., Oval, Boxwood, and Ivory, 232, 234. Phillip's Self - Registering Maximum, 314. ,, Physicians', for temperature of human body, page 160, 162. See also Clinical Thermometer. ., Pit, 342*. Porcelain mounted, 223, 271. Thermometers, Patent Atmospheric for Recording, pages 52, 53. Rutherford's Self- Registering Minimum, 318. Reference Standard, 39. Registering Maximum. various, page 162. Self-Registering, page 162 to 166. ., Sixe's Self -Registering Maxi- mum and Minimum, page!64. ., Soap-boiler's, 345. Standard, pages 32 to 50. Steam Pressure, page 174. Saccharometer, 383. Stands, page 79. Screen, for Sea use, fig. 89. Sugar boilers', 347. Super-heated Steam, 372. Surgical, pages 160, 500. Slow Action, 402. Spiral Bulb, 42. Sea Coast or FitzRoy, 341. Still, 361. Salinometer, 379, 517. Travelling, 71, 237. Upcast Shaft, 369. Vacuum pan, 367, 415. Vatting, 284. Valve Regulating, 357. Varnish Maker's, 354. Vinegar Maker's, 352. Veterinary, 311. Well, 400. Window, or Bracket, page 154. with Glass Scales, 228. on Stands, with Glass Shades and various mountings, 243 to 250. Therm ometrical Salinometer, 417. Thermometric Hygrometer, Leslie's, 84. Theodolite, Underground, 1149. Thermostat, 358, 2965. Thermo- Pressure Gauges, page 174. Thermo-Electric Apparatus, page 450. Thermoscope, Electric (See Melloni's Pile). Thermoscopic Spectacles, page 222. Thomson's Electrometers or Galvanometers, 169, 170, 2676. [page 119. Water Dropping Collector, 3139, Thunder Cloud Apparatus, 2470. House, Electrical, 2471. Tide Gauge, page 120. Sir W. Thomson's, 175, page 122. Improved, page 516. Self -Registering, page 120. 45, COENHILL, E.G., AND 122, REGENT STEEET, W., LONDON. 599 Tide Table, page 562. Tilley's Water Pressure Blowpipe, 2175. Timber Rule, 1703. Time Glasses, page 325. Time Clocks with Electric Alarm for Factories, &c., 2825. Tinted Glass, Photographic, cut To Order. Tin Vessel, with Stopcock, &c., 2950. Timber Measuring Rods, 1703. Tithonometer. Draper's, made To Order. Tobacco Pipe, brass, for Gas Experiment, 2190. Tongs, Crucible, 2209. Tops, Colour, 724. Tops, Colour, Dr. Gorham's Kaleidoscope, 725. Torricellian Experiment, 2873. Torricelli's Experiment, page 2. Tourmalines, 1066. Artificial, 1063. Toxological Test Chests, 2372. Tracing Paper, 1644. Transfer Cloth, 1645. Transferer, Single and Double, 2855, 2856. Transit Instruments, pages, 254 283. Transparent Eye Shades or Protectors, 3115. Tripod Stands, Photographic, page 526. Trammels, see Beam Compasses, page 337. Transparent Screens for Dissolving Views 1792. Transmission Instruments, or Counters, pages 200, 467. Travelling Cases and Boxes for Photographic Apparatus, To Order. Travelling Sets of Meteorological Apparatus, page 123. Travelling Sets of Photographic Apparatus, page 553. Tracer, 1528. Trays, flat Porcelain or glass, 3266, page 452. or F'rames for Photographic Portraits. To Order. Washing, 3273. Trevyllian's Experiment, 3058. Triangles, Steel, 1623. Triangular Drawing Compasses, 1531. Trinket Compasses, 316, 317. Trochiameter. page 297. Troughs, Galvanic Battery, page 436. Mercurial, 2020, 2276. Trumpets, Speaking, 1430. T Squares, page 341. Tube Bottles, 1923. ,Tube Compasses, 1546. Tube, Divided, 1949, 1993. Tubes, Air Jar, 1892. Animalculae and Fishing, 1001. a series of six, to illustrate Capillary Attraction, 2935. Berlin Porcelain, 2105. Bulb, 1930. Collecting. 999. Chloride of Calcinm, 1935. Conducting, bent, 1932. Cubic inch, 1949. Drying or Dessicating, 1967. Dropping, 1961, 1962. Dumas's Gas, 1999. Kerr's, 2001. Eudiometrical, page 380. Flasks, 2103. Graduated Gas, 1998. Induction, for Magnetizing Needles 2998*. Letter Z, 2108. Pulse, 2044. Receivers, 2056. Reduction, 2045. Retorts, 2104. sets of four, for experiments with Air, 2887. Spirit Level, page 289. Suction, 2088. Test, 2102. U, 2109, 2064, 2988, 2567. V shape, 2063. ., V, for decomposition, 2567. ,, Vacuum, page 453. Vulcanised Caoutchouc, 2348, 1786. 3-limb, 2108. Tubing, Combustion, German Glass, 1934, 2003. India Rubber, 2235. Flint Glass, 2004. Gauge, for Steam Boilers, 2006, page 197, 566. German Glass, 2003. Tumblers, Beaker, 1917. Turpentine Bulbs, 2110. Turn-in Dividers, Pocket, 1538. Twaddell's Hydrometer (see Hydrometers). Tyndall's Friction Heat Apparatus 2954, 3045. U Tubes, 2564. U Convection Tubes, 2988. Udometres (see Eain Gauges). Ullaging Rule, 1673, page 345. Unannealed Glass, 1060. 600 NEGBETTI AND ZAMBEA, HOLBORN VIADUCT, E.G., Underground Theodolite, page 290. Temperature Registering Ther- mometers, Negretti & Zambra's Patent, pages 171, 34, 35. Undershot Wheel, model of, 2941. Universal Sun Dials, pages 312 to 314. Studio Camera, 3193. Scales, Architects', Builders' Engineers', &c., pages 339 to 348. Uranium Glass Tubes and Vessels, 2766. Urea Tubes, 546. Ure's Udiometer, 1971. Nitrogen Apparatus, 2143. Ure's Steam Apparatus, 2947. Urinometers, page 191. Metal, 540. Test Paper, 541 . Urinary Cabinets, page 192. Vacuum Gauges, pages 196, 205 to 209. Gauges, Mercurial, page 196, and For Air Pump, No. 2857 A 7 acuum Tubes, G-assiot's, 2742. . ,, Carbonic Acid, 2744. for Throat, &c., 3092. Geissler's, page 452, 2745. Vacuum Tubes, with Mottoes, 2746. Diadem or Coronet, 2749. Pan Thermometers, 367, 415. Valentine's Dissecting Knife, 980. Valve Regulating Thermometers, 357. Vanes, Wind, see Anemometer, and page 96. Variation of the Mariner's Compass, pages 318, 327. Varley's Telescope Stand, made To Order. Varnish, Photographic, page 552. Varnish for Glass painting,1886. Varnish, Crystal, Negretti & Zambra's, 4014. Varnish Makers' Thermometers, 354. Varrentrap's Nitrogen Apparatus, 2144. Ventilation, apparatus to illustrate, 2991. Velocity of Electricity, page 563. Light, page 563. Sound, page 563. Wind, pages 97, 99, 103. Vernier, use of described, pages 6, 7. Veroe's Malt Gauging aud Ullage Rule. 1687. Verification of Standard Meteorological Instruments at Kew, page 125. Veterinary Thermometers, 311. Vibrating Electro-Magnet, 2695. Steam Engines, models of, 3003. Vibration Telephone, 3069. Vice for Table, 2349. Vice or Clamp for Holding Tubes or Retorts. 2332, 2339. Views, for Disolving View Apparatus, and Magic Lantern, pages 364 to 374. Albumen for ditto, page 369. for Polyorama, 758. ,. Stereoscopic, Glass and Paper, page 233. Vibrating Wires, Marsh's, 2688. Vidi's Aneroid, page 21. Videoscope, 759. Vinegar Makers' Thermometers, 352. Hydrometer, 476. Vignette Glass Plates, 3288. Vision, model to explain theory of, 745. Visuometer, 760, 3302. Vital Heat, pages 161, 560. Vital Capacity of the Lungs, Table of, page 499. Voltaic Cautery Apparatus, 3120. Piles, 2513, 278C. Voightlander, Vienna, or Orthoscopic Lenses, supplied To Order. Volta's Couronne de Tasse, Silver and Zinc wires for, 2515. Electrophorous, 2386. Eudiometer, 1970. Condensing Electroscope, 2412. Pile, 2513. Volta-meter, 2565. Volumeter, Gay Lussac's, 508. Volumeter, 2123, page 394. V Tube for decomposing neutral salts. 2567. Vulcanised India Rubber Tube, 2196. Vulcanite Electrical Machine, 2383, 2384. Cells, 2578. Electrophorous, 2388. Walker's Battery, 2547. T., Patent Harpoon Log, page 324. Telegraph Testing Apparatus, 3154, page 514. T., Patent Sounding Machine, page 324. Cherub Log, page 325. Bliss's Log, 1400. A.. Liverpool Patent Ship Log, page 324. Sounding Machine, page 324. Washing Bottles, 2117 to 2122. Dishes and Trays, page 542. Trough, Syphon, 3273. Watch-sized Aneroid Barometer, page 24. . Compass and Trinket. 1344 and page 317. Glasses, 2111. 45, CORNHILL, E.G., AND 122, REGENT STREET, W., LONDON. 601 Watchmaker's Magnifiers, 700. Watchman's Comptroller, Patent, Supplied To Order. Water Battery, 2541. Barometer, 24. Baths, 2114. Bottle, 2116. Elastic. 2198. Colours, page 344. Hammers, 2112, 2891. Pumps, models of, page 472. Ram, Mongolfier's,2931. Snail, 2929. Troughs, Glass, for Lantern, 1798. Wheels, models of, page 480. Gauges for Boilers, page 197. Pressure, Table, page 480, 559. Water-tight Exciting Baths, 3263. Waves of the Sea, moving Lantern Slide to exhibit, 1824, 1825. Waves, length of, page 67. Wealemefna, 1285. Weather Glasses, see Barometers, &c. Wedge, Gladstone's, 1089. Improved Model of, 3049.* Wedgwood's Pyrometer, 597, 2959. Weed Knife, 1023. Weighing and Measuring Machine, for use with Spirometer, 3090. Machine, Duckham's, 592. Weights, Decimal, 2222. Aluminium, 2353. Grain, Standard, 2358, 2359. French, 2360 to 2362. Troy, 2356. Paper, 1648. Well Fixing Dishes, Porcelain, 3270. Wheatstone's Anorthoscope, 754. Apparatus for determining differential resistance, 2769. Kaleidophone, 3067. Stereoscope, fig. 768. Ditto, Reflecting, To Order. Telegraph Instruments, Magneto Electric, pages 466, 467. Rheostat, 2768. Photometer, 750. Military Telegraph, page 467. Magnetic Counters, page 467. Wheel Barometers, page 136 to 138. Wheels, different forms of, 3047. Whewell's Anemometer, 148. Whirling Rings, 3044. Table, 3044. Apparatus for Gassiot Star, 2733. Whirls, Electrical, 2462. Whistles, Steam, page 210. White Light, Apparatus to show composition of, 718, 724, 725. White Cloud Illuminator, 952. Whole and Half Drawing Compasses, 1545. Will & Varrentrap's Nitrogen Apparatus, 2144. Percy's Apparatus for Alkalies, 2142. Wind Gauges, pages 96 to 111. Vanes, page 96. Windlass, Model of, 3049. Windmills for Air Pump, 2886. Wine or Liqueur Analyser or Test, page 193. Spirit Condensing Still or Alcoholic Test, page 193. ., and Spirit Dip Rule, page 345. Winter's Electrical Machine, 2381. Wire Cage for Breaking Squares, 2898. Conducting, covered with Cotton, Silk, Gutta Percha, &c , 2507, 2584, 2717, 2771, 2799, 2811. Gauge, Milner's, page 348. Gauze Cylinder, Electrical, 2487. Gauze, 2350. Gold, Silver, Platinum, Copper, Magnesium, &c., To Order. Frames, Rectangular (Thermo-elec- tric), 2721. Sliding, and Brass Plate, 2858. Rope Lightning Conductors, pages 127 to 129. Woodward's Electrical Machine, 2382. Wollaston's Cryophorous, 1948, 2970. Calorimotor, 2523. Galvanic Battery, 2520. Goniometer, 753. Steam Apparatus, 2996. ' Boiling Point Apparatus, 131. Wood Boards for preparing Paper, To Order. Clips, 972, 3291. Woolwich Set of Drawing Instruments, 1481. Woulffe's Bottles, page 394. Writing Diamonds, 2224, 1003. Wurtemburg Syphon, 2091. Yacht Signal Lamps, pages 322, 323. Compass, page 319. Aneroid Barometers, page 149. Barometers, page 145. Binnacles, pages 319, 326. Y Level, best, 1127 to 1 130. Y Shaped Keepers for Magnets, made To Order. Youth's Chemical Cabinets, page 409 2 R 602 NEGBETTI AND ZAMBRA, HOLBOEN VIADUCT, E.G., Zamboni's Electric Pile, 2116. Zanett's Hydrometers, in sets of 6 ; with these Instruments Specific Gravity is obtained by adding a cypher to the number of degrees indicated ; made To Order. Z Glass Tubes, 2108. Zinc & Copper Plates soldered together, 2514. ,. with Glass handles, 2516. Zinc Dish for Waxing Paper, 3296. Zinc Plates, Amalgamated, 2582. Zinc and Copper Sieves, 2517. Tables, Meteorological, various, page 133. Thermometric, pages 51, 169, 566. Boiling Point, pages 93, 175. Hygrometric, page 76. Eain Fall, page 81. Kelative Lengths and";Weights of Copper Wire, page 455. Water Pressure, pages 480, 559. Approximate Height due to Baro- metric Pressure, pages 3, 557. Horse Power of Steam Engines, page 559. Expansion by Heat, page 560. Various English and Foreign Weights and Measures, &c., pages 554 to- 557. Earth Temperatures, pages 34, 172. Atmospheric Pressure, page 480. Tables, Heat disengaged during combus- tion, page 560. of relative Temperatures and Pressures, page 65, 175. of relative Temperatures and Pro- portions of Salt in Marine Boilers, page 189. of Specific Gravity of Vinegar,. &c., page 184. of Oils, 474, page 184. of Velocity of the Wind, pages 97 to 101. Baker's Comparative Hydrometer. 558, page 195. Comparative Scale of values of Twaddle's Hydrometers, page 183. Vital capacity of the Lungs, p. 499\ Table of Mean Winter, Mean Summer, and Annual Mean Temperature, 566. Equation Table, 562. Spring Tide Table, 562. Table of Differences from Greenwich. Time,. 562. 35AYMAN BROTBEP.S & LKM/T, HATTON SOUSE, 113, FARRINGDON KOAI), LONDON, E.Ci- RETURN TO DESK FROM WHICH BORROWED riRCULATlON DEPARTMENT This-Book is due on the last date stamped below, or on the date to which renewed. 4kHBB^ >ooks are subject to immediate recall. jUN 2 1976 9 EEC. CIB. MW 25 7 KC.CB. SEP 976 LD21 32w 1,'75 (S3845L)4970 General Library University of California Berkeley UNIVERSITY OF CALIFORNIA LIBRARY U. C. BERKELEY LIBRARIES coumomm Bl