Meteorological Register. 149 
From these curious and interesting experiments, Sir George 
Knox infers, that the bitumen, being similar in smell, colour, 
and volatility, existed previously in the stones, and was not 
formed by the fire, although he admits this to be possible ; sd 
thinks the ammonia* a product, and not an educt. He i 
quires whether the conversion of obsidian into pumice dies 
not justify the arrangement of those two substances together ; 
ether volcanic fires may not have their origin in rocks o 
the floetz trap formation, since bitumen, or a volatile inflamma- 
ble oil, is combined with them all. He thinks the i gerne 
of inflammable matter in mica and slate remarkable, and th 
it is equally so that rock crystal and adularia are destitute of 
this principle. He infers from the scintillation of the powder 
of stones with nitre, that carbon may be much more exten- 
sively diffused through the mineral kingdom than has been 
imagined, and suggests that re should be a regular 
part of analysis—that ‘ Jess” ought not, of course, to be 
charged to water, as bitumen and carbon are now proved to 
be often present, and that the residuum in the retort ought to 
be examined for carbon, either by burning it off, or in some 
other way. 
ArT. XXI.—Notice of a nchaet ad ig Register for the 
years 1822, 1823, 1824, and 1825; from observations 
made by the Sy peont of the any, at the Military Posts 
of the United States. 
WE have been favoured by Dr. Lovell, surgeon general of 
the United States army, with this able and important document. 
It is the result of very numerous observations, made under 
favourable circumstances, at fixed stations, over an extent of 
country embracing nearly 20 degrees of latitude, and almost 
30 of longitude. 
The scientific world will feel much indebted to the en- 
lightened policy which dictated this course rva- 
tions, constituting the best basis for general conclusions re- 
* Are we to infer. then that nitrogen exists in these stones, or must we im- 
pute this Faieuiest of the ammonia to atmospheric air in the pores : vessels * 
DITO: 
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