162 Dr. Thomson's First Principles of Chemistry- 
the superstructure of earth composing the body ofthe mound, 
evidently showing that the dead had here been reduced to 
ashes, after the manner of several ancient nations, and that 
the mound of earth had been erected over the remains, to 
perpetuate the memory of some companion or friend. 
Mounds are generally found on level land, and near streams 
of water, thereby indicating that the dead were deposited 
near their settlements. Some mounds are oval, and others 
circular. Those vast remains of mounds, elevated squares, 
parapets, ditches, &c. on the elevated plain, within the town 
plot of Marietta, have been so often described, that I shail 
not attempt it at this time.” 
Art. XXII.—Notice of Dr. Tromson’s first principles of 
Chemistry ; and extracts from foreign letters on various 
subjects, addressed to the Editor. 
fr is not within our purpose, or present limits, to do any 
thing more than briefly mention the admirable work of Dr. 
Thomson. For more than twenty years, we have diligently 
followed this distinguished author, through al! the numerous 
editions of his systematic Chemistry, in which he has shown 
himself the vigilant and faithful historian of the science ; 
through his Annals of Philosophy, one of the best of the nu- 
merous scientific journals of this day, and through his smaller 
works, and separate memoirs, with which he has favoured the 
public ; and we have listened, with high interest, to the in- 
structions of his lecture room. But after all, predisposed, 
as we were, to expect much from a great effort of the mature 
age of such a master, our expectations have been more than 
equalled. ‘There is nothing, the offspring of the present age, 
which, so far as we are informed, surpasses this ‘* attempt 
to establish the First Principles of Chemistry by Experi- 
ment.”? The vast amount of labour performed—the patient 
and persevering repetition of tedious and often difficult pro- 
* See the descriptions and drawings, by Caleb Atwater, Esq. in the 
first Vol. ofthe Archceologia Americana, where much very interestidg 
guformation may be found.—-Editor. 
