244 
CHAS. E. SANDO 
The coloring matter was deposited from water as a mass of crystalline aggre- 
gates, as illustrated in figure i. 
The substance, crystallized from alcohol (figure 2), forms glittering 
"ferruginous"^ thin plates having a metallic luster. It is readily soluble 
in pyridine, slightly soluble in cold ethyl alcohol, methyl alcohol, acetic 
ether, ether, and acetone ; very sparingly soluble in cold water, and insoluble 
in acetic acid, toluene, benzene, carbon tetrachloride, chloroform, carbon 
disulphide, and petroleum ether. By warming, it is readily soluble in 
Fig. 2. Photomicrograph of crystals of endothine red purified from alcohol. 
alcohol, but sparingly in water, acetic ether, and acetone. When warmed 
with glycerine on a water bath a red solution results. 
Dilute alkalis dissolve it with a violet red color; the addition of dilute 
acid to this solution changes it to yellow. 
Concentrated sulphuric acid gives a "perilla purple" solution. 
Cold concentrated nitric acid has no effect on it even after standing 
24 hours, but upon gentle warming a faintly colored solution results. 
Alcoholic ferric chloride produces with very dilute solution of the pig- 
ment a greenish "raw sienna" color; with more concentrated solutions a 
"dull greenish-black" precipitate is obtained. 
Color descriptions placed in quotations indicate that they were taken from Ridgway, 
Robert, Color standards and nomenclature. Washington, D. C, 1912. 
