89 



yielding a sublimate of yellow lustrous scales and needles. 

 It is almost insoluble in boiling water, but dissolves easily 

 in concentrated sulphuric acid, even in the cold, giving a 

 cherry-red solution. It does not dissolve sensibly in caustic 

 potash lye in the cold, but on boiling a bright cherry-red 

 solution is obtained, which on cooling deposits dark red 

 crystalline masses. The solution shows no trace of absorp- 

 tion bands, but onl/ a general obscuration of the green part 

 of the spectrum, and in this respect differs widely from the 

 alkaline solutions of alizarine, which exhibit such ver}^ 

 characteristic absorption bands. The solution in concen- 

 trated sulphuric acid does, however, show an absorption 

 band on the border of the green and blue, just like a solution 

 of anthraflavic acid in the same menstruum, but far less 

 distinctly than the latter, on account of the much greater 

 obscuration of the parts of the spectrum adjacent to the 

 band. On adding alcoholic potash solution to an alcoholic 

 solution of methyl-alizarine the potassium compound is 

 deposited in dark red needles, arranged in star-shaped 

 masses. The sodium compound, prepared in the same way, 

 crystallises in small light red needles. A watery solution 

 of the potassium compound gives with chloride of barium a 

 red flocculent precipitate. The alcoholic solution of methyl- 

 alizarine gives no precipitate with acetate of lead. When 

 treated with boiling nitric acid methyl-alizarine is dissolved 

 and decomposed, and the solution on evaporation leaves a 

 white crystalline residue, probably of phthalic acid. Methyl- 

 alizarine undergoes no change when treated with strong- 

 caustic potash lye, even at the boiling temperature. It is 

 only when fusing hydrate of potash is employed that de- 

 composition takes place. If the operation be carefully con- 

 ducted there is obtained, on the addition of water to the 

 fused mass, a violet -coloured solution, which shows the 

 absorption bands of alizarine very distinctly. There is no 

 doubt, therefore, that by the more energetic action of the 



