271 
PART IV.-NATURAL HISTORY. 
REVIEWS AND EXTRACTS. 
I.— Journal of Agriculture, &:c. Published Quarterly. 8vo. 
price () 5 . 
No. 14, FOR August, contains 
An interesting Article an Geology, viexeed in relation to Agricnltnre. By W. 
M‘Gillivray, A.M. 
The experienced agriculturalist may judge correctly, (says the writer) of the g-e- 
neral capabilities of a district, from a superficial inspection, and may perceive its 
adaptation to the cultivation of certain plants, or to the rearing of certain species 
of animals, in consequence of a single glance of the eyej but it is not to the 
agriciiltHralist alone that a knowledge of Geology is of importance, for it will rea¬ 
dily be perceived that as the rocks, and other materials which the exterior of the 
globe afibrds, are applicable to numerous purposes in the arts, a more correct 
knowledge of them than that derived from superficial inspection, must be of deci¬ 
ded utility ; however, the chief object of the writer, is to impress upon the mind of 
the cultivator of the ground the advantase he miofht derive from such a deg-ree of 
attention to the science in question, as might afford a correct idea of the rock 
deposites, without inducing him to run the risk of bewildering himself among the 
idle speculations to which their phenomena and relations have given rise. 
Of the agents which have produced the greatest modifications upon the surface 
of the globe, those which may first occupy our attention are Volcanoes and Earth¬ 
quakes. Volcanoes are openings in the outer layer of the globe, through which 
are emitted various substances, generally in a state of fusion or incandescence, 
together with aeriform fluids. They are usually situated on the summit of de¬ 
tached mountains, and present at their extremity, the form of a funnel, to which 
the name of Crater is given. Volcanoes are of very general distribution, although 
large portions of the globe are entirely free from them. They usually form series 
of immense extent, frequenlly running in right lines, although widely differing 
from each other. Of these great series, one of the most remarkable is that pre¬ 
sented by the chain of the Andes, which, extending from Patagonia along the 
western coast of South America, forms the isthmus by which the two great por¬ 
tions of the western world are separated, traverses Mexico, and continues its 
course northward into the rocky mountains of North America. From Patagonia 
to Mexico upwards of sixty V'olcanoes are known to exist in this range. Another 
great range of V'olcanic action commences in the Aleutian Archipelago, and ex¬ 
tends to Kanjschatka, the Kurile Isles, the Japanese and Phillipine Islands, Loo 
Choo, Celebes, and the Moluccas, where it branches off to the east and west. In 
Europe there are few active Volcanoes; Mount Etna in Sicily, Vesuvius on the 
opposite coast of Italy, Stromboli in the Lipari Islands, Ilecla, and five others in 
Iceland, are all that are known. According to D’Aubuisson, M. Ordinaire esti¬ 
mates the number of active Volcanoes at 205, of which 107 are in islands, and the 
other 98 on the continents. 
It is a remarkable circumstance, that all the V'^olcanoes which are at present in 
a state of activity are situated in the vicinity of the sea. It is also well known 
