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la ted over them ? Immediately after thole two primary 
lets of Jr at a, we find, all over our Continents, frata form¬ 
ed of- calcareous fubftances. With thefe you do not appear 
embarrailed : you think it fo certain that they were 
formed from the relicts of fra animals, jhat you lay this 
down as a .f .cl not nece'Fary to be proved: but, fir, are 
thole pretended animal relicts the accumulated product uf 
that fucceflion of changes of fea into land, and (and into 
Jca, m which co.nfifts the peculiarity of your hyporliefis ? 
or, haye all thefe fubftances been produced in that -fea 
which has immediately preceded the prefent? I (hall 
anfwer, iff. f hat,we fee no pure calcarccvs fubftance mi¬ 
grating from our continents toward tire f a, to form there 
calcareous Jtrata finiil'ar to ours ; and that, confequ.ently, 
Inch a (uppofition would he gratuitous, zd. That the 
general idea, of a feparate migration from the land of dif¬ 
ferent unmixed materials, keeping again feparate in the 
Jca, though accumulating upon one another in diftinft 
Jlrata, is abfi lately chimerical. It would at firft appear 
lets improbable, that tl’.e whole of our calcareous Jlrata 
had been produced in the former fea: however, this alfo 
is contrary to all phenomena of that ejafs. iff. Why are 
thofe pretended rclitis of fea animals depofited in fo many 
frata, infteadof forming only one mafs ? 2d. Why 
do we find as great accumulations o f marine bodies, in frata 
not calcareous , as in the calcareous ones ? 3d. How were 
the calcareous jlrata accumulated all over the bottom of 
the former J'ea, unmixed with any other fubftance: while 
the land is fuppofed to have furnifhed, at the fame time, 
the materials of the other forts of frata accumulated over 
thofe? Thefe remarks are only general ideas, which I 
offer to your meditation; and 1 am fure, that when you 
come to examine attentively fotne of the parts of our 
continents which exhibit fucceffive and diftinCl claftes of 
Jrata, you will, yourfelf, be glad to find, in the follow¬ 
ing pages, a twilight fpread on that grand phenomenon, 
by the theory of diJJblution and precipitation , which at firft 
appeared to you fo abfurd. 
It is a very common facl, that water may depofite con¬ 
crete fubftances, which afterward it cannot dijfolve . This, 
principally, is the effect either of the emijfiqn of fome 
elafic jluid, whofe ingredients, previoufiy dfjblvcd by wa¬ 
ter, had enabled it to dijfolve the fubftances now precipi¬ 
tated ; or of water, at the time of that precipitation, dif- 
folving fome other fubftance. Thofe are operations per¬ 
formed in many ways, fpontaneoufty upon our continents, 
and artificial in our laboratories : and by analogy to thofe 
known operations, I (hall undertake to fhew, that the 
whole of our ftrata has been produced by precipitation. 
We clearly perceive in th tjucceffion of our Jlrata a variety 
of diftincl operations, nearly the fame, in every refpedt, 
all over our continents; which, in the firft place, muft 
have been performed (hiring periods diftindt from each 
other, not only in point of time, but by elfential diffe¬ 
rences in the productive caufes ; and which alfo mu ft 
have begun at a diltinCt epocha of the exiftence of our 
globe. Thefe are undoubtedly in the number of the 
moft important circumftances to be explained in a Theory 
of the Earth ; and, in the mean time, the^ point out preci¬ 
pitation, not merely as a vague caufe, but as the caufe 
which affords the cleared idea of a beginning, and is the 
moft fufceptible of modifications adequate to that variety 
of diftindl effects. We are frill, no doubt, too ignorant 
in natural hiftory and chenriftry, to form a fixed and pre- 
cife theory of thofe-operations ; but we can trace their 
out-lines; and this I fh all attempt. In this (ketch of tire 
hiftory of the earth, prior to its prefent ftate, I fix upon a 
very remote, but diftindt, epocha, from which I (hall 
come down to the complete formation of our continents. 
At that time, light did not exift : but, that fubftance 
excepted, our globe contained all the ingredients from 
which were to refult its prefent ftate, and that of its at- 
vicfphere. In the number of thofe ingredients, were the 
condiment particles of water, and another fubftance, 
which, with light, forms Jire, Ho’liquid exifled in that 
R T FT. 
ftate of the earth, becaufe fire, which is a neceffary part 
of their compofitioh, did not exift. This is a moft ma¬ 
terial point, not only in the hiftory of the earth, but in 
natural philofophy ; and, from the general principles of 
that fcience, together with indubitable facts, I have 
fhewn, (in my work, Ideesfur la Metedrofogie,) that light is 
one of the condiment parts of Jire, as certainly, as this is 
a conftituent part of water, of aqueous vapour, of aeriform 
fluids, and of numberlefs other elafic and non-clafic lub- 
ftances. To thefe propofitions I here refer; and, from 
that determined ftate, in which our globe was once, I 
propole to trace the operations which have produced our 
continents. 
First Period.— A great event changed that primor¬ 
dial ftate of the earth, which, elfc, had exifted everlast¬ 
ingly ; this was the addition of light to the confufed mafs 
of its ingredients; and the following were the immedi¬ 
ate confequenees of that addition : ift. From light, united 
to one of the ocher fubftances, fre was compofed, and the 
various effects of heat began. 2d. The moft immediate 
effedt of the exiftence of fire, was iA union with the con¬ 
ftituent particles of water: from which that univerfal li¬ 
quid was produced. 3d. From fire alfo, and front fepa¬ 
rate light, the production of all the atmofpherical fuids 
took place in determined circumftances. 4th. Water dif- 
folved fucceffivelyya variety of fubftances; being unable 
to perform fome of thofe dijfolutions by antecedent ones.- 
3th. A number of other fubftances, fome of a difficult 
fojution, fome infoluble in that firft ftate of the liquid^- 
fubiided in it, and promifeuoufiy formed the unliquefied 
part otpur globe. 6th. When foftnefs had been thus pro¬ 
duced in the mafs of our globe, it aflumed, lay gravity 
and by its rotatory-motion, the form that it now wears. 
Second Period. —An original liquid being"thus com¬ 
pofed, it began to diffpToe fome of the fubftances which, 
at firft, had fubfided; and that diJMutidn, together with 
t he emifiion of various elafic fuids, occafioned, in the 
great'eft part of the liquid, the funultaneous ^rav^zhz-, 
tions of two forts of cryftallized fubftances, of mica and of 
other powders, which, altogether, compofe granite. In 
other partsjaf the liquid, different fubftances, partaking 
of the nature of the former, were promifeuoufiy precipi¬ 
tated-, and, laflly, in fome parts, a pure quartzeouspowder. 
That firft general precipitation, and all the following ones 
of other kinds, were intermittent; becaufe of the How. 
nefs of the communication of the precipitating fubftances 
from the bottom to higher parts of the liquid, and of 
the flow nefs alfo of the emifiion of elafic fuids from its 
fnrface downward. To thofe intermifllons were owing 
diftinCt frata, formed in the courfe of each diftincl preci¬ 
pitation. A mixture of proper particles, both in fize and 
in form, precipitated together in a liquid, is an adequate 
caufe to produce the multitude of points of clofe conta£l r 
necelfary to ccnfo/idate a mafs by cokfon : and that circum- 
ftance having exifted in a high degree in thofe firft frata , 
they formed a very hard and thick crufi at the bottom of 
the liquid all over the globe. The fame caufe, but 
with different combinations, produced various degrees of 
folidiiy in mod parts of the fubfequent frata. During 
that period, the liquid emitted a great abundance of 
aqueous vapour and of other elafic fluids, which formed a 
firft atmofphere round the globe. 
Third Period. —The formation of granite and of other 
quartzeous frata, was fuccceded in the liquid, by very 
different precipitations. To this feriod belongs, efpe- 
cially, the grey rock intermixed with the {Vwcting frata 
called fchifus, which, all over our continents, appears-as 
having formed immenfe frata over the granite. At fome 
part of this period, a great effect was produced, which, 
by its repetitions in the following periods, has been the 
immediate caufe'of all the revolutions undergone by our 
frata-, and the following was its firft caufe. After the 
Jblid cruf had been produced on our globe, the loofe fub¬ 
ftances on which it was laid, having continued to (brink 
in many parts, by gravity, and by a more intimate com. 
4 ’ * biaation 
