38 
earthquake, by the falling in of some works at the distance of 
a quarter of a league. 
With respect to the shocks felt at Nice, the author says, that he 
had carefully compared the list published by M. Risso, with the ac- 
counts of eruptions of Vesuvius and Etna; and that though some 
of the earthquakes had preceded, by very short intervals, certain 
powerful eruptions of those volcanoes; yet, in very many 
instances, the shocks appear to have been quite independent; and 
that a considerable number of eruptions, both of Vesuvius and 
Etna, had not been felt at Nice. Hence, he infers, that, in this case, 
there may have been earthquakes due to volcanic, as well as non- 
volcanic, agents ; and that Nice, standing upon a gypsum forma- 
tion, may have felt the effects of volcanic eruptions im consequence 
of a predisposition in the undermined ground, without which they 
would not have been perceptible at the surface. 
M. Necker objects to the earthquake in Calabria, in 1783, being 
considered of true volcanic origin, because it was unaccompanied by 
any disengagement of heat, lava, smoke, acid, or sulphureous pro- 
ducts; because the surface of the ground was depressed, not ele- 
vated; because only sand and water were ejected through the fis- 
sures and circular or star-like cavities formed in the ground, and be- 
cause there was no eruption of Vesuvius or Etna. The earthquakes 
in the valley of the Mississippi, during 1812, he conceives were 
non-volcanic, in consequence of no lava having been poured forth, 
nor any acid or other vapours emitted. He alluded to a letter by 
Mr. Stanley Griswold, dated Kaskahia, Illinois, the 22nd of Dec. 
1812, which describes some of the phenomena of the earthquakes,— 
particularly the subterranean noises resembling thunder, the cracks 
formed in the ground, the issuing of ‘“‘ a something”’ like smoke, or 
warm aqueous vapour, accompanied by a great quantity of sand, 
the ejection of carbonised wood, coal, and pumice, a quantity of 
which is said to have been collected on the Mississippi, the drymg 
up of lakes, and the raising of the bed of the river. To some of 
these statements M. Necker objects. He conceives that the smoke, 
or warm aqueous vapour, which is mentioned only from the reports 
of others, and not decidedly, may have been mistaken for vapour 
produced by water striking against an immoveable obstacle. The 
occurrence of pumice, he conceives, is very doubtful; and, as it is 
mentioned by no other author, he withholds his assent till the sub- 
stance has been examined by a competent mineralogist. 
M. Necker dissents from the Cutch earthquake in June, 1819, 
being considered volcanic. ‘The elevation of the Ullah Bund, he 
conceives, was effected by the subsidence of the ground towards 
Sindree, or to a movement on a fixed axis. ‘The materials thrown 
out by the shocks were only black mud, sand, wrought iron, and 
nails, and could not therefore, he says, have been produced from 
any great depth. 
The earthquakes on the coast of Cumana, and the Caraccas, M. 
Necker considers to be non-voleanic ; and that when the number and 
