73 



glacial acetic acid, therefore, a substance was obtained appa- 

 rently pure and bomogeneous, the more soluble matter remain- 

 ing in the motber liquor. Tbe red colouring matter tbus 

 obtained crystallises in small scarlet plates, magnificently 

 brilliant in sunlight. It melts at about 192°-193° C, is soluble 

 in boiling alcohol and glacial acetic acid, but sparingly soluble 

 in tbe cold liquids, and almost completely precipitated by 

 -water. It dissolves in solutions o£ tbe caustic alkalies, forming 

 a deep violet-red solution, but is immediately precipitated from 

 these solutions by acids. Analysis shows it to possess the for- 

 mula CnHgOg, and its chemical characteristics point to its 

 bearing a somewhat similar relation to the hydrocarbon metJiyl- 

 oiapJithalene, as purpurin does to anthracene — in fact, it resem- 

 bles purpurin in some respects. On oxidation it yields acetic 

 acid and carbonic anhydride, and is probably a metJiyl-trihy- 

 droxy-Qiaplithaquinone. On reduction with a strong solution of 

 stannous chloride it yields a pale yellow crystalline substance 

 containing two atoms more hydrogen than the original. 



The second substance can be obtained from the mother 

 liquors by first precipitating with water, and then submitting 

 the precipitate to special treatment with strong (not glacial) 

 acetic acid. The quantity obtained was small, and not suf- 

 ficient to make sure of its purity ; but it crystallises quite dif- 

 ferently from its fellow, is much more soluble in all solvents 

 tried, and gives a red solution with caustic alkalies, without 

 any tinge of violet. Its melting point is nearly 30° lower — 

 about 165°. Its analysis points to the formula CnHgO^; that 

 is, it contains an atom less oxygen than the substance first des- 

 cribed, but is closely related to it. 



I hope to obtain a further supply of material next spring, 

 and to further investigate these interesting substances. 



