108 



CHEMISTRY. 



discovered a more ready mode of preparation, 

 by which they obtain the article chemically 

 pure. They find, on boiling finely-powdered 

 commercial indigo with aniline, that the 

 whole of the coloring-matter dissolves, yield- 

 ing an intensely deep-blue solution, most of 

 the impurities being left behind. The solution 

 is filtered while hot, and allowed to cool grad- 

 ually. In five or six hours almost the whole 

 of the indigotin is deposited in a crystalline 

 state. A second crystallization from an ani- 

 line solution, followed by alcoholic washing, 

 purifies it perfectly. As thus prepared, indi- 

 gotin has a brilliant coppery lustre by reflected 

 light, in this respect resembling pure Prus- 

 sian blue, and rivals in appearance the indi- 

 gotin obtained by sublimation. The authors 

 have also discovered that, to some extent, 

 indigotin is soluble in hot benzol and chloro- 

 form, depositing itself as a flocculent precipi- 

 tate on the solution cooling, Alcohol and 

 ether also dissolve it at their boiling-points, 

 but in very small quantity. 



New Coloring - Substances. Pyrogallic acid 

 melted with naphthalic acid and other ingre- 

 dients (not mentioned by Prof. Baeyer, the 

 discoverer) yields a coloring-substance, which 

 he calls " gallein." This appears as a brown- 

 ish-red powder, or as metallic-green crystals. 

 On boiling these with water, zinc, and sul- 

 phuric acid, the color changes to light-reddish 

 yellow, and, after further treatment, large 

 brownish crystals fire obtained, to which the 

 name "gallin" has been given, and of which 

 ** gallein " forms a small part. Heating " gal- 

 lin"" with concentrated sulphuric acid to 200 

 Cent., its color changes to a greenish brown, 

 and, after the reaction is completed, and the 

 mass has been boiled, and the deposit washed, 

 another coloring-matter, " cerulein," appears. 

 This is soluble in hot water, and imparts an 

 indigo-blue color. "Reforcin" and "fluores- 

 cin," the latter dyeing silk and wool yellow 

 without a mordant, are other products discov- 

 ered in pyrogallic and naphthalic acids by 

 Prof. Baeyer. 



Prof. Botger has ascertained that, by dissolv- 

 ing molybclic acid in concentrated sulphuric 

 acid with heat, a colorless fluid is obtained 

 supposed to be a double acid. When a little 

 of this is heated in a porcelain crucible till it 

 throws oif vapors, and absolute alcohol is 

 added, a blue color appears, which can be 

 used to dye silk without a mordant. 



Artificial Bases. In the address of Dr. An- 

 drews, president of the Chemical Section of 

 the British Association, at its last meeting, 

 mention was made of recent triumphs in pre- 

 paring artificial bases. Picoline is one of 

 these, a base isomeric with aniline. Baeyer 

 discovered the process of its artificial manu- 

 facture, for which he has two methods. One 

 is founded on an experiment of Simpson, in 

 which a new base was obtained by heating 

 tribromallyl with an alcoholic solution of 

 ammonia. By pushing further the action of 



the heat, Baeyer succeeded in expelling the 

 whole of the bromine from Simpson's base 

 in the form of hydrobromic acid, and in 

 obtaining picoline. The same chemist haa 

 also prepared artificially collidine, another 

 base of the pyridine series. To this list of 

 remarkable synthetical discoveries, another of 

 the highest interest has lately been added by 

 Schiflf the preparation of artificial coniine. 

 He obtained it by the action of ammonia on 

 butyric aldehyde (X^HsO). The artificial base 

 has the same composition as coniine prepared 

 from hemlock. It is a liquid of an amber- 

 yellow color, having the characteristic odor, 

 and nearly all the usual reactions, of ordinary 

 coniine. Its physiological properties, so far 

 as they have been examined, agree with those 

 of coniine from hemlock, but the artificial 

 base has not yet been obtained in large quan- 

 tity nor perfectly pure. 



New Bases. Stenhouse has obtained two 

 new bases, furfuraniline and fnrfurtuluidine, 

 by the treatment of aniline furfurol. The 

 bases are nearly colorless, but form beau- 

 tifully-colored salts. By treating codeia with 

 chloride of zinc, Matthiessen and Burnside 

 have obtained apocodeia, which stands to co- 

 deia in the same relation as apomorphia to 

 morphia, an atom of water being abstracted 

 in its formation. Apocodeia is more stable 

 than apomorphia, but the action of reagents 

 upon the two bases is very similar. As regards 

 their physiological action, the -hydrocblorate 

 of apocodeia is a mild emetic, while that of 

 apomorphia is an emetic of great activity. 

 Other bases have been obtained by "Wright by 

 the action of hydrobromic acid on codeia. In 

 two of these bases, bromotetracodeia and 

 chlorotetracodeia, four molecules of codeia are 

 welded together so that they contain no less 

 than seventy-two atoms of carbon. They 

 have a bitter taste, but little physiological ac- 

 tion. 



Pyrene is the name given to a new product 

 of the distillation of coal-tar, having a higher 

 boiling-point than anthracene. It may be iso- 

 lated by combining it with picric acid, with 

 which it forms a red crystalline mass. Am- 

 monia unites with the acid and sets free the 

 pyrene in the form of colorless leaves which 

 closely resemble anthracene, are soluble in 

 alcohol, benzol, ether, and bisulphide of carbon. 

 It melts at 142 C. Nitric acid readily con- 

 verts it into nitro-couipounds. The formula 

 of pyrene is Ci 8 Hio. 



lodo- Sulphates. Prof. Zinno, of Naples, 

 obtains the little-known compound iodo-sul- 

 phuric acid from the reaction of ioduret of 

 starch and sulphuric acid. He prepares the 

 acid and its salts by the following modes: 

 1. With alkaline sulphates and iodoret of 

 starch ; 2. By dissolving some determinate 

 proportions of iodine and the solution of the 

 said sulphates ; 3. By making the iodine act 

 on the hyposulphates of alkali; 4. By the 

 action (already mentioned) of sulphuric acid 



