82 1 
thit solid matter must have been 4,500 times greater than that of water, 
and more tC 200 times heavier than platinum! As to the action of 
. mt|„ tvt Oaeniard de la Tour long ago proved by experiment, that 
thfr^s^ alcohol did the same ’ exertin S a 
^sfe«aas®« 
‘r“ -a* 
more remains than for me to describe the simple means employed for d. eter- 
mXlThe specific gravity of the constituent parts of granite, and I do this 
wTa S nleLant hope^hat others will be induced to repeat my labours. To 
bottle wSX being filled up with distilled water, was weighed, and the 
weight so found deducted from 1 500 gave a res ult to ' b e used g a ^ j 
the 500 grains accu- 
rateS thl common plan of weighing in water aidngkpie^e; 
are always fissures and sometimes cavities in minerals and these : hssmes 
in fact, the greatest difficulty in the whole proceeding. 
Having read this paper, I must now once more repeat that it does net 
carry conviction to my mind. Without attempting to criticise it throughout, 
I shall briefly notice one or two of the points wherein it appears to me to be 
defective. Mr. Thompson promised us facts ; but he has only given us e 
result of a single experiment. And what does it teach us 1 Not, m my 
opinion, what he draws from it. He melts a few hundred grams o gmmte 
and lets it cool ; and he obtains something like obsidian. He tells 
fused granite cooled rapidly ; and he assumes that had it cooled more s ow y 
it would have cooled into granite, instead of obsidian. I must demur to that 
assumption. The experiment appears to me only to prove that, if the mate- 
rials of granite were ever in a state of fusion, the result would be some 
homogeneous matter like obsidian, and not granite. He thinks the resi 
would have been different if the fused granite had been more slowly cooled 
But he has not verified that by experiment. He has given us no -acts to 
prove this conclusion. I will notice another point where the reasoning doe 
