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THE POPULAR SCIENCE MONTHLY. 



for 255 yards of Turkey-red cloth. "We are 

 at present acquainted, among the deriva- 

 tives from coal-tar, with about sixteen dis- 

 tinct yellow colors, about twelve oranges, 

 more than thirty reds, about fifteen blues, 

 seven greens, and nine violets ; and a num- 

 ber of browns and blacks, besides mixtures 

 of the several chemical compounds, giving 

 rise to an almost infinite number of shades 

 and tones of color. These colors are capa- 

 ble of a rough arrangement according as 

 they are originally derived from one or 

 other of the hydrocarbons contained in the 

 coal-tar. In the class called azo-colors, an 

 azo or nitrogen group replaces the hydro- 

 gen in phenols and amido-compounds. They 

 are chiefly bright scarlets, oranges, reds, 

 and yellows, with a few blues and violets. 

 Next in importance to the color industry 

 comes the still more novel discovery of the 

 synthetical production of antipyretic medi- 

 cine. The initiative in the production of 

 these compounds was given in the discovery 

 by Professor Dewar, in 1881, that quinoline, 

 their basis, is an aromatic compound ; from 

 it he obtained aniline. Kairine, the first of 

 the antipyretics in the order of discovery, 

 is manufactured from quinoline. It effects 

 a remarkable lowering of the temperature 

 of the body, which, however, is of much 

 shorter duration than that effected by qui- 

 nine ; but, with the exception of its burning 

 taste, it exerts no such evil effects as arc 

 often observed after the administration of 

 large doses of quinine. Antipyrine, the 

 second of these febrifuges, was discovered 

 in 1883. It is made from aniline and 

 accto-acetic ether. As a febrifuge, it is su- 

 perior in many respects to kairine and even 

 to quinine. It equals kairine in the cer- 

 tainty of its action, while in its duration it 

 resembles quinine. It is almost tasteless 

 and odorless, is easily soluble in cold water, 

 and takes the form of a white crystalline 

 powder. Its use in medicine is accompanied 

 by no drawback. A third artificial febri- 

 fuge is thalline, which is said to be used as 

 an antidote for yellow fever. None of 

 these substances are anti-pcriodics ; and 

 consequently they can not supplant quinine 

 in cases of ague and intermittent fevers. 

 Another group of coal-tar products com- 

 prises the artificial aromatic essences. 

 Among these are cumarine, the principle of 



"new-mown hay"; vanilline, of vanilla, 

 with its derivative vanillen, which is used 

 in preparing " essence of heliotrope " ; mir- 

 bane, a soap-perfume, and the artificial oil 

 of bitter almonds. The most remarkable of 

 all the coal-tar products is probably saccha- 

 rine, a substance which surpasses sugar in 

 sweetness. It is not a sugar, for it con- 

 tains sulphur and nitrogen, nor does it act 

 as a nutriment, but it is non-poisonous, and 

 passes out of the body unchanged. 



A Lesson in Practical Anthropology. 



Sir C. W. Wilson, in a paper read in the 

 British Association, on " The Wild Tribes of 

 the Soudan," after describing the tribes and 

 their clans, with their divisions and alliances, 

 remarked that it was interesting to observe 

 how thoroughly General Gordon had under- 

 stood the situation in that region, and at 

 once pointed out the remedy. When he left 

 England, his instructions had been to pro- 

 ceed direct to Suakin, open up communica- 

 tion with the supreme sheik of the Iladen- 

 dowas who had taken no part in the rebel- 

 lion, and isolate and crush Osman Digma by 

 raising against him the surrounding tribes, 

 whose sheiks he knew personally. There 

 can be little question that if this policy had 

 been carried out early in 1884, before 

 Sinkat fell and Baker Pasha had been de- 

 feated, it would have been successful. But, 

 unfortunately, General Gordon's plans were 

 changed and he proceeded up the Nile. Mr. 

 Hyde Clarke congratulated the section on 

 having had such a paper submitted to them, 

 and said that Sir Charles Wilson had given 

 them a useful exemplification of the value 

 of anthropological studies. They had seen 

 how incidents in the war in the Soudan had 

 turned rather on the knowledge of the men 

 than of the physical features of the country. 



Photography of the Stars. Professor 

 Edward S. Holden has given, in the " Over- 

 land Monthly," a popular account of the 

 methods and an estimate of the expecta- 

 tions of stellar photography. The photo- 

 graphic telescope requires special construc- 

 tion and arrangement of the lenses, which 

 differentiate it from ordinary telescopes. If 

 it is set fixed, the image of the star pass- 

 ing across the sensitive plate will leave a 

 "trail," which is the visible representative 



