254 Proceedings of Royal Society of Edinburgh. [sess. 
boiling-point. After one or two trials I used benzyl chloride, 
C 6 H 5 CH 2 CL, having a specific gravity of 1‘1 00, and a boiling-point 
178° C. The only objection to this is its irritating vapour. It is 
well not to allow any of the fumes to get into the eyes, or somewhat 
painful smarting will result. 
