GRANITE. 31 for structural purposes, to observe the quantity of water they are capable of absorbing, as the influence of frost on stone is in proportion to the quantity of water it takes up, and the result determines to some extent its durability. The power of granite to resist crushing forces varies much with the character of the rock. The valuable series of experiments made by Mr. Wilkin son on the granites of Ireland, show considerable variations even amongst selected specimens. Cubes of one-inch sides having been tested by means of a lever, specially prepared by Mr. Mallet, C.E., it was found that the weight in lbs. required to crush the specimens varied from 2310 up to 13,400, the maximum being obtained from a specimen from Newry, County Down; the minimum from Bally- knockan. The granites from Killiney and Kings town afforded good results. 1 1 Prac. Geol. and Arch, of Ireland, by G. Wilkinson, M.R.I.A. (i845 )