18 
Proceedings of the Poyal Society of Edinburgh. [Sess. 
(U.S. Geological Survey Bulletin , 442, 32) has suggested the use of an 
asbestos sheet with a perforated sheet of stout platinum foil in the centre. 
The silica plate has the advantage of cheapness and rigidity, and has been 
found in practice to be very useful in quantitative analysis. 
The holes were bored on a lathe by means of a copper tube of ap- 
propriate size, the cutting end being covered with carborundum and 
lubricant. Doubtless the manufacturers of silica ware would supply these 
perforated plates. 
Chemistry Department, 
University of Edinburgh. 
{Issued separately January 31 , 1912 .) 
