234 PROCEEDINGS OP THE AMERICAN ACADEMY. 



melted at 111 . He also gives analyses which agree very well indeed 

 for the body in question. 



Von Pechmann,* three years later, obtained a body by the action of 

 an excess of bromine upon benzolresorcinephthaleni, which he called 

 tribromresorviue on the ground of the melting point of 103°. He 

 gives no analysis of this body, notwithstanding the fact that Benedikt 

 had previously found its melting point to be 111°. 



Beilstein in his "Handbuch" gives only Typke's mehiug point 

 of 104°. 



All of the tribromresorcine we have made use of in this research 

 melted at 111 , the point given by Benedikt, and repeated recrystal- 

 lization from water, which seems to be preferable to all other solvents, 

 failed to raise its melting point higher. 



According to Hlasiwetz and Barth,f tribromresorcine when recrys- 

 tallized from water contains water of crystallization, which it loses at 

 100°. As the presence of water of crystallization might explain the 

 differences in the melting points given by previous observers, we 

 examined the tribromresorcine in this direction. Some of it was crys- 

 tallized from hot water and dried in the air to a constant weight. 

 This air-dried salt, which remained constant in a desiccator over cal- 

 cic chloride, was heated to 100° for ten hours, when 0.2169 gram of the 

 substance lost but 0.4 milligram in weight. Therefore tribromresorcine 

 when recrystallized from water does not contain water of crystalliza- 

 tion which it loses at 100°, as Hlasiwetz and Barth state. 



In the recrystallization of the tribromresorcine from hot water, 

 especially from boiling water, it was noticed that the crystals had 

 a light pink color, so a study of the action of boiling water upon this 

 body was taken up. One gram of the pure tribromresorcine was boiled 

 in a 500 c. c. flask, fitted with an inverted condenser, with 250 c. c. of 

 water. The greater part of the solid went into solution, and after the 

 boiling had proceeded but a very short time the liquid became pink 

 in color, which deepened into a dark red after the action had been 

 carried on for twenty-four hours. The portion of the tribromresor- 

 cine which did not go into solution melted under the boiling water, its 

 color also changing from a pink to a very dark red after the boiling 

 had been continued for some time. At the end of twenty-four hours' 

 boiling, we found that all of the tribromresorcine had not been 

 changed into the red body, for on cooling crystals of a light pink 

 color separated from the solution, which had the melting point of 



* Ber. d. ch. G., XIV. 1061. t Ann. Chem., CXXX. 357. 



