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Band 27.1883
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- Titelblatt Titelblatt I
- Register Index III
- Ausgabe No. 1270, January 5, 1883 1
- Ausgabe No. 1271, January 12, 1883 17
- Ausgabe No. 1272, January 19, 1883 33
- Ausgabe No. 1273, January 26, 1883 49
- Ausgabe No. 1274, February 2, 1883 65
- Ausgabe No. 1275, February 9, 1883 81
- Ausgabe No. 1276, February 16, 1883 97
- Ausgabe No. 1277, February 23, 1883 113
- Ausgabe No. 1278, March 2, 1883 129
- Ausgabe No. 1279, March 9, 1883 145
- Ausgabe No. 1280, March 16, 1883 161
- Ausgabe No. 1281, March 22, 1883 177
- Ausgabe No. 1282, March 30, 1883 193
- Ausgabe No. 1283, April 6, 1883 209
- Ausgabe No. 1284, April 13, 1883 225
- Ausgabe No. 1285, April 20, 1883 241
- Ausgabe No. 1286, April 27, 1883 257
- Ausgabe No. 1287, May 4, 1883 273
- Ausgabe No. 1288, May 11, 1883 289
- Ausgabe No. 1289, May 18, 1883 305
- Ausgabe No. 1290, May 25, 1883 321
- Ausgabe No. 1291, June 1, 1883 337
- Ausgabe No. 1292, June 8, 1883 353
- Ausgabe No. 1293, June 15, 1883 369
- Ausgabe No. 1294, June 22, 1883 385
- Ausgabe No. 1295, June 29, 1883 401
- Ausgabe No. 1296, July 6, 1883 417
- Ausgabe No. 1297, July 13, 1883 433
- Ausgabe No. 1298, July 20, 1883 449
- Ausgabe No. 1299, July 27, 1883 465
- Ausgabe No. 1300, August 3, 1883 481
- Ausgabe No. 1301, August 10, 1883 497
- Ausgabe No. 1302, August 17, 1883 513
- Ausgabe No. 1303, August 24, 1883 529
- Ausgabe No. 1304, August 31, 1883 545
- Ausgabe No. 1305, September 7, 1883 561
- Ausgabe No. 1306, September 14, 1883 577
- Ausgabe No. 1307, September 21, 1883 593
- Ausgabe No. 1308, September 28, 1883 609
- Ausgabe No. 1309, October 5, 1883 625
- Ausgabe No. 1310, October 12, 1883 641
- Ausgabe No. 1311, October 19, 1883 657
- Ausgabe No. 1312, October 26, 1883 673
- Ausgabe No. 1313, November 2, 1883 689
- Ausgabe No. 1314, November 9, 1883 705
- Ausgabe No. 1315, November 16, 1883 721
- Ausgabe No. 1316, November 23, 1883 737
- Ausgabe No. 1317, November 30, 1883 753
- Ausgabe No. 1318, December 7, 1883 769
- Ausgabe No. 1319, December 14, 1883 785
- Ausgabe No. 1320, December 21, 1883 801
- Ausgabe No. 1321, December 28, 1883 817
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SEPTEMBER 28, 1883. | THE PHOTOGRAPHIC NEWS. 615 PHOTO-LITHOGRAPHY AND PHOTO ZINCOGRAPHY. BY MAJOR J. WATERHOUSE, B.S.C., Assistant Surveyor-General of India. Chap. XIII.—Asphalt Processes—(continued). From the results of analysis Kayser gives the following as composition. Syrian Trinidad Carbon ... 80-00 ... 78-80 Hydrogen 9.00 ... 9-30 Sulphur... 10-00 ... 10 00 Nitrogen 040 ... 1-40 Ash ... 060 ... 0-50 100-00 100 00 of these five asphalts, Dr. representing their average Bechelbronn Maracaibo Barbadoes ... 86-00 ... 81 65 ... 87-04 ... 11-40 ... 9-59 ... 9-56 ... 1-40 ... 8 03 ... 2.67 ... 0-30 ... — ... — ... 0-50 ... 0-34 ... 0 24 99-60 99 61 99 51 The Syrian, Trinidad, and Maracaibo asphalts, which are hard and solid, may be considered as sulphuretted hydro carbons, and those from Bechelbronn and Barbadoes, which are viscous and softer, as solutions of sulphuretted hydro-carbons in solid or fluid hydro-carbons. By successive treatment with boiling alcohol (sp. gr. 8 35), boiling ether (sp. gr. 0-725), and chloroform, Dr. Kayser found that the Trinidad and Syrian asphalts may be separated into three components, differing in their chemical composition and photographic properties. Syrian asphaltum, powdered and treated several times with boiling spirit (sp. gr. 0-835), as long as any colour appeared, yielded, on evaporation of the spirit, 4 per cent, of a yellow oily substance, with an intensely bituminous smell; slightly soluble in cold spirit, more easily in boiling; easily soluble in ether, benzole, chloroform, and turpentine ; insoluble in solutions of caustic alkalies. By heating it, fluid decomposition products and sulphu retted hygrogen are formed, with a small residue of carbon. Analysis shows this substance to be composed of— Carbon 83-08 Hydrogen 9-95 Sulphur ... 6-97 100-00 with a formula C2H4°S. Trinidad asphaltum treated in the same way with boiling spirit yielded 5 per cent, of a similar substance of different composition, viz.— Carbon ... . 79-47 Hydrogen 9-93 Sulphur 10-95 99-35 with the formula C20H3oS. If the residue left by extracting Syrian asphalt with alcohol be treated in the same way with boiling ether (sp. g. -725), on evaporation of the ether a brownish black, resinous, brittle mass remains. It is almost odourless, and begins to melt at 65® C. (149° F.). It is insoluble in cold or hot alcohol, but soluble in the other solvents. Weak solutions of it are yellowish brown with a green fluorescence. Syrian asphalt contains 44 per cent, of it, its composi tion being— Carbon 80-33 Hydrogen 9-62 Sulphur 1004 with the formula C64H92Sa. Trinidad asphalt treated in the same way contains 57 per cent, of a similar substance, commencing to melt at 54® C. (1292° f_). its composition is— Carbon 80-70 Hydrogen 9-94 Sulphur 9:35 99-99 with the formula C23H34S. Maracaibo asphalt contains a similar substance, melting about 50® C. (122° F.), and containing 6 88 per cent of sulphur. The substance obtained by treating Barbadoes asphaltum with ether has a yellowish brown colour, melts about 40® C. (1048 F.), and contains no sulphur. The residue remaining after extraction of the parts solu ble in alcohol and ether is dissolved in chloroform, filtered, and the chloroform removed by distillation. With Syrian asphaltum there remains 52 per cent, of a resinous, very brittle, shiny-black, odourless mass, with a melting point about 156° C. (313° F.). It is easily soluble in chloroform and turpentine, with difficulty in benzole and petroleum. Weak solutions are brownish yellow, with green fluorescence. Ether precipitates it from its solution in chloroform. By heating it, fluid products, sulphuretted hydrogen, and charcoal are formed. Its composition is— Carbon 78.37 Hydrogen ... ... ... .. 8-57 Sulphur 13-06 10000 with the formula C2H*2S*. Trinidad asphaltum treated in the same way yields 38 per cent, of a substance similar to and identical in com position with the last, but melting at 150? C (302® F.). Maracaibo asphaltum also contains a component insolu ble in ether, melting at 160° C. (320° F.), and containing 11-49 percent, of sulphur. In Barbadoes asphalt, this component melts at 161“ C. (322° F., and contains 11-09 per cent, of sulphur. According to John, asphaltum treated in the same way with anydrous alcohol and ether yields 5 per cent, of a yellow resin soluble in rectified spirit and ether; by digest ing the residuum in ether, a further 70 per cent, of a brown ish black resin is obtained, which is freely soluble in the volatile oils, and is about five times its weight of mineral naphtha. The portion (25 per cent.) left undissolved by ether is very soluble in the oils of turpentine and petro leum. The proportion of the substance insoluble in ether appears to be very variable in different samples. The writer found that four specimens gave respectively 60 per cent., 55 per cent., 45 per cent., and 30 per cent. According to Dr. Kayser, the component insoluble in ethers is, as a rule, easily soluble in chloroform and turpentine, less so in benzole and petroleum. John also notes its easy solubility in turpentine. The writer has found, however, that in the case of five different samples of asphaltum of unknown origin, the residue remaining after extraction with ether lost its solubility in turpentine, although in three cases it was easily and perfectly soluble in it before extraction, and was also less soluble in other solvents. Of chloroform, benzole, turpentine, oils of lavender, rosemary, marjoram and lemon, chloroform appeared to be the only perfect solvent. In some cases the addition of ten per cent, of thymol to the turpentine greatly increased its solvent powers, some of the extracts dissolving entirely in it, others partially, but more abundantly than they did without the thymol. The solution in chloroform seemed to leave a brittle, in coherent coating, which cracks on drying. It seems, therefore, that the action of the ether and alcohol is to extract the oily and softer constituents which bind the mass together, leaving a hard, dry, pulverulent residue, much less soluble in most solvents than the asphaltum from which it was extracted..
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