372 



REIBLING AND REYES. 



those from the hydroxide, but in this case more water is required to 

 complete the crystallization because the oxide must first hydrate and in 

 so doing absorbs about one-third of its own weight of water. 



These facts were made clear by a method which is illustrated in 

 figure 1. 



9 3 «• 



Q: 

 uj 

 k 



o 

 + 



Uj 

 k 



o 

 + 





CM 



+ 



Uj 



k 



k 

 O 



<0 



o 



Or 

 + 



ca(oh) 



CA 



CA 



ca(oh) 



CA 



Pig. 1. — Sealed tubes showing the effect of water on the formation of calcium hydroxide- 

 phenol crystals. 



Five test tubes were taken, each of which contained 0.25 gram of pure, dry 

 calcium oxide or hydroxide, 30 cubic centimeters of absolute chloroform, 1.5 gram 

 of phenol and the amount of water specified in the illustration. The tubes were 

 sealed, shaken for eight hours, and then their contents allowed to settle. Calcium 

 oxide and hydroxide have a higher specific gravity than chloroform. In tubes 1 

 and 2, where no water was present, they were not acted upon, and have settled 

 to the bottom of the liquid with their original bulk unchanged. On the other 

 hand, the crystals of calcium hydroxide-phenol are specifically much lighter than 

 chloroform. In tube 3 with two drops of water there was incomplete reaction 

 and the mixture does not show a sharp line of separation. In tubes 4 and 5 with 

 four and six drops of water respectively, the change has practically reached com- 



