182 Proceedings of the Royal Society of Edinburgh. [Sess. 
approximation, then, gives no better representation of results than that 
formerly used, and the approximation 
y n {x + a) — b 
>• 
can be regarded as sufficiently good. This is only what might be expected 
from the fact that the logy, log(cc + a) curve consists of two very accurately 
linear parts meeting at a very sharply defined point. 
{Issued separately April 23 , 1913 .) 
