errata. 
Page 78. foot-note, for 82 read 75. 
by Prof ' F - H - S “ 0W ( P ublished in ‘^Transactions of 
t* ™ Academy of Science 
rf^ D X-vrr w r^^,r,°^o ground as an articie witfr simiiar 
title, abstract of which is given on page 87. 
