with Mercurie Iodide. ag 
boiling point of water, mercuric iodide becomes yellow. If, 
therefore, the new substances were mere mixtures on being 
heated to that temperature the red color previously acquired 
should disappear completely, since there could be no possible 
cause for its continuance. The mere mechanical mixture of two 
yellow substances (in the case of AgI and Hgl), or of a white 
and a yellow (in the case of AgCl and Hel), could by no pos- 
sibility produce a red one. This single argument would seem 
to be sufficient in itself. 
18 a loose one. By repeated boiling with a considera € quan- 
tity of water, most of the mercuric iodide can be dissolved out, 
