172 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



Co, 



The adapter was so arranged that the current of gas came as closely 

 as possible in contact with the crucible, and so that any zinc bromide 

 which might condense in a liquid form upon the glass, and thus run 

 the risk of taking alkali from it, must return to the crucible and be 

 redistilled. The sectional drawing will give a clearer idea of the 

 arrangement. 



Two powerful Bunsen burners supplied heat from below, impinging 

 upon a porcelain dish which fitted closely to the bottom of the retort 



and protected the platinum. The 

 gases from the flame were diverted 

 by a large diaphragm of asbestos 

 board. By means of this arrange- 

 ment it is possible to sublime about 

 half a gram of zincic bromide an 

 hour ; the crystals are exceedingly 

 beautiful, and give every evidence 

 of great purity. 



Instead of being sublimed, some 

 of the pure salt was distilled in a 

 current of carbon dioxide. For this 

 purpose a medium sized tube of the 

 hardest glass was drawn out so as 

 to serve for a small retort, and this 

 was encased in a larger hard glass 

 tube, from which it was separated 

 by several pieces of platinum foil. A platinum boat, into which was 

 directed the drawn out and turned over point of the inner tube, 

 served as the receiver. Here again a diagram must assist the 

 explanation. 



Sca/e J nd/iwai size 



Scale, y nataral size 



The zinc bromide thus distilled possessed a peculiarly brilliant white 

 lustre ; in no case did the boat lose or gain the twentieth of a milli- 

 gram in weight during the distillation. 



