222 Scientific Intelligence. 
t eigh 
crystalloid rocks (acid and basic magmas of Durocher) of physical 
pro Ww y assume not very different from those 
British units of heat, developable from each cubic foot of its 
material, if crushed to powder. It results from this that each cubic 
mile of the mean material of such a crust, when crushed to pow- 
der, develops sufficient heat to melt 0°876 cubic miles of ice into 
212° Fahr., or to boil off 1°124 cubic miles of water at 32° into 
steam of one atmosphere, or, taking the average melting point of 
rocky mixtures at 2,000° Fahr., to melt nearly three and a 
cubic miles of such rock, if of the same specific heat. 
Of the heat annually lost by our globe and dissipated into space, 
i pte ne 777 cubic miles of ice melted, as before stated, the 
chi 
the extreme case, and supp 
globe loses annually resulted from the transformation of the wor: 
of internal crushing of its shell, we shall find that the total volume 
of rock needed to be crushed in order to produce the requi 
amount of lost heat is perfectly insignificant as compared with the 
volume of the globe itself, or that of its shell. For, as 1:270 cubic 
miles of crushed rock develops heat equivalent to that required to 
melt one cubic mile of ice to water at 32°, and if we assume the 
volume of our globe’s solid crust to equal one-fourth of the total 
volume of the entire globe, 987 cubic miles of rock crushed 
annually would supply the whole of the heat dissipated in that 
time. But that is less than the one siaty-ive millionth of the 
volume of the crust only. 
But a very small portion of the total heat annually lost by our 
globe is sufficient to account for the whole of the volcanic energy 
of every sort, including thermal waters, manifested annually upo® 
