of the Mineral Kingdom.” 197 
i am persuaded that what I have written will produce happy 
effects. The tract upon volcanoes is founded upon experimental 
science and real knowledge of natural history; and, therefore, [ 
hope, that in time, very happy consequences will result from my 
essay upon this subject; in composing which, the whole powers 
of my soul were animated and exerted in fervent desires of doing 
good. 
The dissertations concerning the balance of the waters of the 
ocean, and the accumulated mountains of ice and frozen snow, 
which mutually and reciprocally depend upon and illustrate one 
another ; concerning the peopling of America by land from the 
north-east of Asia, and its being stocked with land animals from 
Armenia, in an early age, before the mountains of frozen snow 
were greatly accumulated ;—concerning the pestilential effects 
of humid vapours arising from the slime of new-formed lands, 
from marshes and extensive woods in warm countries, and how 
to mitigate these dismal calamities, and to banish these under- 
mining enemies of the human race ;—concerning the deepening 
and improving the beds and bars of the navigable and other rivers 
of the world, and the draining and improving of marshes, new 
formed, and wood-lands, with the great and glorious conse- 
quences of such works, for the health, longevity, general happi- 
ness, and prosperity of all nations; are humbly submitted to the 
examination and censure of such candid and benevolent philoso- 
phers as make advances in useful improvements, and the pro- 
sperity and happiness of mankind the ultimate end of the exer- 
tion of their talents. 
In these dissertations they will find many valuable hints, which 
they can improve, and a great deal of matter of vast importance 
and consequence to the health and welfare of the world, very ill 
put together, and in an uncouth dress, but which they may ar- 
range, improve, and clothe in better language. 
Since writing the above, and all I proposed to advance at pre- 
sent in the following essays, I have perused a New Theory of the 
Earth, by James Hutton, M.D. F.R.S. Edinburgh, concerning 
which I beg leave to make a few remarks in this place. 
Dr. Hutton is a naturalist of eminent abilities, whose know- 
ledge in several branches of mineralogy does honour to his coun- 
try, as some of his observations in the treatise under review 
clearly evince. The’ propositions he states, with the conclusions 
he draws from them, to confirm his hypothesis in the theory of 
the earth, shall be the subject of the following observations. 
The Doctor’s general system in his theory of the earth may 
be comprised in these four propositions, 
Ist. That all our rocks and strata have been formed by sub- 
N 3 sidence 
