1867.] Chemistry. 99 



when heated forms styrol. These and other interesting results will 

 be found fully described in the ' Comptes Kendus ' for November 

 5th and 12th, 1866. 



The occurrence of homologous compounds among the products 

 of destructive distillation, has received another illustration at the 

 hands of Dr. Anderson,* who has found propionic and butyric 

 acids in the crude product of the distillation of wood. 



Mr. Skey, a chemist at the Antipodes, sends wordf that a sub- 

 stance resembling artificial tannin is produced by the action of nitric 

 acid on bituminous coal or lignite. The substance is soluble in 

 water, has a bitter taste, and is precipitated from its solution by 

 gelatin and albumen. 



Dr. E. Wagner has recently published:]: what would appear to 

 be a very satisfactory process for the determination of gallo-tannic 

 acid. It depends upon the insolubility of tannate of cinchonine. 

 The author prepares a slightly acid solution of sulphate of cin- 

 chonine, 4*523 grammes in a litre. 1 cubic centimeter of this 

 solution answers to 0*01 gramme of tannic acid. As indicator 

 the solution is coloured with acetate of rosaniline. Kosaniline 

 being also precipitated by gallo-tannic acid, a red colour is left, 

 when the reaction has ended. In applying the test the author boils 

 10 grammes of the substance in pure water, dilutes to 500 c.cs. 

 filters, and then takes 50 c.cs. to precipitate with the cinchonine 

 solution. The precipitate collects together, and it is easily seen 

 when all the tannic acid is thrown down. The calculations, and a 

 number of determinations made by the process, will be seen in the 

 paper quoted from, in which it is also mentioned that the precipi- 

 tates may be put aside and the cinchonine recovered for subse- 

 quent use. 



Frohde has lately shown§ that molybdic acid gives a sensitive 

 and characteristic reaction with morphia. He dissolves molybdic 

 acid in strong sulphuric acid, and a drop of this solution shows, 

 with the smallest amount of morphia, or its salts, a beautiful 

 violet coloration, which soon passes to blue, afterwards turns 

 dirty-green, and, lastly, leaves a nearly colourless spot. A solution 

 of molybdate of soda in sulphuric answers well for the test, which 

 is said to be more sensitive than nitric acid. 



Chloroform is subject to spontaneous alteration, which results 

 in the disengagement of phosgene gas. Although the nose will 

 generally serve to discover the presence of this gas, a delicate test 

 is useful, and Stadeler points out that bilirubin, the red colouring- 

 matter of bile, answers the purpose. When this body is brought in 



* ' Chemical News,' No. 365, p. 257. 

 t ' Chemical News,' No. 861, p. 206. 

 X 'Zeitschrift f. Analyt. Chem.,' 5, 1. 

 § • Archiv. <fc r Pharm.' Brl. 186, p. .VI. 



H 2 



