128 On the geological Theory supported by Mr. Smithson 
that mass of facts that justify the hypothesis, of which it may be 
supposed the author adduces the most striking: he thus con- 
tinues: “* The mighty difficulties which formerly assailed this opi- 
nion, great modern discoveries have dissipated. Acquainted now, 
that the bases of alkalies and earths are metals eminently oxi- 
dable, we are no longer embarrassed either for the pabulum of 
the inflammation, or to account for the production of it. In 
the primary trata we behold the result of combustion: in them 
we see the oxide collected on the surface of the calcined mass, 
first melted by heal, then by its increase arresting further com- 
bination, and extinguishing the fires which had generated it, and 
in fine become solid and crystallized over the metallic ball. 
Every thing tells that a large bedy of' combustible matter re- 
mains inclosed within the s/ony envelope, of which volcanic 
eruptions are partial and small ascensions. Under this point of 
view, a high interest attaches itself to vo/canoes and their 
ejections; they cease to be local phenomena; they become 
principal elements in the history of our globe ; they connect its 
resent with its former condition.” 
This surely is as new, as it is a grand system ; but what is its 
foundation? The author tells it himself in the title of his paper ; 
it is on a saline substance from Mount Vesuvius ; and he informs 
us that it was sent to him from Naples, while he was at Florence 
in May 1794, with the request of ascertaining its nature ; after 
which he thus continues: “ The general examination which I 
made of it, showed that it was what at that time was called 
vitriolated tartar, and it was in consequence mentioned as such 
in an Italian publication soon after.” 
Then he gives the following particulars concerning the man- 
ner in which that substance had been found: ‘1 was informed 
by a letter, that it had flowed out liquid from a small aperture 
in the cone of Vesuvius, which 1 apprehend to have happened 
in 1792 or 1793.” 
Thus we may judge, that the author has never observed him- 
self Mount Vesuvius, and that he knows. only by report a few of 
the phenomena of that volcano. He then proceeds to detail the 
chemical analysis which he had made of that saline substance ; 
but as he is aware that-so small and even so indirect a fact 
could not support his 7gveous system, he ventures on another 
ground, in which I shall now follow him, and afterwards return 
to volcanoes. 
“In support (he says) of the igneous origin here attributed 
to our primizive strata, 1 will observe that, not only no crystal 
imbedded in them, such as quartz, garnei, tourmaline, &c. has 
been seen inclosing drops of water, but that none of the materials 
of the strata contain water in any state.” 
The 
