372 
in a platinum crucible, which fits to one extremity of a 
platinum tube, to the other extremity of which is adapted 
a small platinum receiver, (the junction between the 
latter being rendered air-tight with caoutchouc, and the 
receiver and tube being immersed in a freezing mixture of 
ice and snow,) no solid or liquid product is obtained in the 
tube or receiver; the fluoride of silver is converted into - 
cyanuret of silver; and a gas is evolved, which has a 
stronger effect upon the eyes and throat than hydrofluoric 
acid, producing sickness, headache, and vertigo. This gas 
acts strongly upon glass, reddens litmus, and burns in the 
flame of a spirit lamp with a yellowish light. It remains 
for a considerable time in the platinum vessel, showing that 
its specific gravity is greater than that of atmospheric air. 
The same gas is obtained, when a current of gaseous 
cyanogen is passed over fluoride of silver fused in the pla- 
tinum tube. 
