EARTH. 
body. As scientific men were gradually 
admitted to the knowledge of the secrets of 
the earth, by the exertions of the miner, in 
the same proportion did all ideas of a chaos 
vanish, and we are now convinced, though 
their excavations are mere punctures in the 
globe, that were it possible to penetrate 
thi’ough, it would tend to prove that self- 
existing causes, originating immediately 
from the Creator, are constantly employed 
in preserving the whole from derangement, 
and what we term decay, which, in truth, 
is simply a change of form, and not annihi- 
lation. The celebrated miner. Agricola, 
was the first who recorded the internal pro- 
perties of the earth, between whose time 
and that of AVerner, some discoveries were 
made as to its structure ; Lehman formed 
the idea of primitive and secondary classes 
of mountains. Cronstadt conjectured the 
age of several mineral repositories. Ha- 
milton, Dolomieu, and Spallanzani have 
gone to very successful and satisfactory 
lengths in ascertaining the operations of 
volcanos. The nature of the materials 
which support them, and the substances 
they eject, Saussure has increased our know- 
ledge of rocks, AVilliams of the independent 
formation of coal, and Werner has profited 
by every preceding observation, and possess- 
ing a cultivated genius of his own, united 
them into a system which approaches 
nearer to the truth than the nature of the 
subject would lead us to suspect. Unfor- 
tunately the labour and expense of pene- 
trating to any great depth into the earth, 
ever has and ever must limit our know- 
ledge of the extent of strata, and its simila- 
rity in different latitudes, but from the op- 
portunities already afforded by mines, we 
are led to conclude that those lines of mat- 
ter spread through vast spaces, if not 
throughout the globe ; many theories have 
been attempted to account for their va- 
rieties and capricious elevations and de- 
pressions from a horizontal direction. Dr. 
Woodward, who deeply considered the sub- 
ject, supposes all the terrestrial masses dis- 
posed in strata to have been dissolved by the 
waters of the deluge, which subsiding the 
most pondrous, fell to the bottom, and the 
rest settled in gradations suited to their 
specific weights. This solution naturally 
disposes the strata uniformly horizontal, 
and he accounts for the breaks in the lines 
and fissures every where observable by the 
action of volcanos, earthquakes, &c. &c. 
Buffon's fancies of corners torn from the 
SUB by comets, and the earth lignilied by 
fire, barely deserve notice, and make a 
disgraceful contrast with Woodward’s in- 
genious conjectures. 'The surface of the 
earth is known by every enlightened per- 
son to be composed of a confused mass of 
vegetable, and in some slight degree of ani- 
mal substances, below which Jameson says 
There are four different kinds of structure : 
- “ The first is that which is to be observed 
in hand specimens j it is the smallest kind 
of structure, and occurs in what are termed 
mountain-rocks or stones. The second kind 
of structure, or that of mountain-masses, is 
more on the great scale, and is not to be 
observed in hand specimens, but only in 
single masses of rock. To this structure 
belongs stratification, and the seams of dis- 
tinct concretions. The third kind of struc- 
ture is that of rock formations, or those 
great masses of which the crust of the earth 
is composed. To examine this kind of 
structure, we must traverse considerable 
tracts of country. The fourth kind of struc- 
ture is that of the earth itself, which is 
formed by the junction of various forma- 
tions. To examine this structure we must 
travel through many countries.” 
Wlien in passing through long tracts of 
land we observe loose rocks, firm rocks, 
clay, sand, &c. &c. in succession, in those 
instances the strata of the earth lay almost 
perpendicular, in large masses of rocks, 
which present nearly a plain front, the in- 
clination of the strata is distinctly visible, 
and in some cases their agreement with 
otliers opposed to them demonstrate that 
they have been separated by some convul- 
sion of the earth. 
The gravity of a portion of the earth was 
calculated by Dr. Maskelyne in the years 
1774 and 1775, at the mountain Schehallien, 
and its attraction on a plummet ascertained 
on each side ; besides which, he computed 
the quantity of matter contained in it by a 
considerable number of sections in various 
directions ; and the result being afterwards 
compared with the acknowledged magni- 
tude and attraction of the earth, he found that 
the density was as 9 to 5 of common stone, 
and as 9 to 2 water; whence it was inferred 
that large quantities of metal lay concealed 
witliin it. Before this period little was 
known of the gravity or density of the earth, 
though the relative densities of that and 
others of the planets had been ascertained 
with tolerable precision. From the data 
thus acquired, the quantity of matter in the 
earth is known to be equal to the product 
of its density by its magnitude; the force 
