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Mineralogy and Geology. » TY 
And thus, the great mass of northern drift. inasmuch as no considera- 
w shai or not we suppose the read tik oyed in the tintributon 
of this mass from the centre to be waves of reanialy ik For e propo- 
equally true, whatever be the machinery employed. As no gradual or 
minute action could move the masses in question through a yard of space, 
no accumulation of such action, through any amount of time, could dis- 
tribute the masses through the great eigen which the northern drift 
hanes versed, and spread them over the vast spaces which that forma- 
The distribution of the peace drift belongs to a peri 
ises operated than those which are now in action. 
bof erhaps it may throw some light upon the subject to 
remark that a. way e of translation differs little from a “ debacle” accord- 
ing to the notions of earlier speculators. A wave of translation is a 
debacle conceived according to the more exact notions to whic 
science has led, Or rather, since a debacle was generally sna / 
vast torrent eee over the land, arising from the emergence 0 
oe ee hccatids area, or some such cause, we may say that a wave of trans- 
lation, i in such cases as we Lave considered, is a debacle travelling along 
_ the sea after it has been shot off the land. 
2. On the Slow Transmission of Heat through loosely peters Clay 
Spat Sand; by James Nasmyrn, Esq. ; communicated in a letter to Leon- 
1RD Horner, Esq., P.G.S., (Lon. Quart. Jour. Geo. Soc., res 1847,)— 
“When I lately had the pleasure to see you at the foundry, on drawing 
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w had an important bearing on several interesting geological ques- 
; tions, especially those relating to the ied of the central heat of the 
earth, 
ao your request | I have much pleasure in sending you a statement of 
pein stance in question, under the impression that it may chance to 
prove of s some - interest as an illustration of what may yet exist in re- 
apoes-an th 
yee will imidrober: was that Pr a large pbieaes pot, 
coplecdag tons of white-hot melted cast-iron—a tem 
re be quite beyeed, all thermometric certainty, but wall k 
hest intensi ee furnace dest, ma aus ee al to 
