1800.} 
rior fatellites. He difcovers, that if the 
bulk of the feventh exceeded =, of that’ 
of Saturn, its action would fenfibly dif. 
tance the orbit of the fixth from the plane 
of the rings. ‘This effect does not take 
place; C. Laplace therefore concludes 
that the bulk of the laft {atellite is below 
that fraction. The fame analyfis, applied 
to the fatellites of Uranus, fhews that the 
aétion of this new planet is fufficient to 
keep its firft-five fatellites ‘in the plane of 
its equator: it is probable, adds he, that 
this attraction is fufficient to retain the 
fixth, but if the bulk of the fifth furpaffed 
the 20,ooo0th part of that of the planet, 
then its action united to that of Uranus 
would be fufficient to retain the orbit of 
the fixth in the plane of the other orbits ; 
which is conformable to the obferyations 
of Herf{chell. » 
| \ 
NATURAL PHILOSOPHY, read by, 
C. Cuvier. 
For along time Volcanos have occafion- 
ed a great deal of trouble to natural philo- 
fophers by the difficulty of explaining their 
phenomena, and efpecially of difcovering 
the fources of that immenfe quantity of 
matter of. every kind which they vomit 
forth in their eruptions. C. Patrin has 
thrown upon this fubject fuch light as 
could only have been ftruck out by a bold 
sfhagination ; in doing which, he has had 
recourfe tall theaid that modern chemiftry 
has afforded him. He fuppofes that the 
water of the fea is perpetually drawn be- 
tween the beds of fhiftus, which com- 
monly form the bafis ef the volcanos; 
that the marine falt is there difcompofed ; 
that its acid furcharges itfelf with oxygene, 
in paffing over the oxyds of iron and man- 
ganefe; that it decompofes the fulphurs of 
iron, and even the water by means of 
carbon: that the various produéts of thefe 
decompofitions combining under other 
forms, yield the pertroleum or hydrogene 
gas, which takes fire and produces the 
moft brilliant part of the volcanic pheno- 
mena; whilft electricity, joining itfelf to 
thefe already numerous elements, forms 
there fulphur and phofphorus. He makes 
the latter of thefe fubftances perform a 
very important part; for he fuppofes the 
oxygene is fixed under an earthy appear- 
ance by it, and confequently through it 
are the volcanos enabled to furnifh that 
enormous quantity of lavas with which 
fhey inundate the furroundine country 
without exhaufting the bafis that fupports 
them. Laftly, the iron is carried along in 
the lavas by a metalliferous fluid; to which 
C. Patsin attributes the property of re- 
i National Inftitute of France, 
Ds 
taining metals in a flate of vapour, depo- 
fiting them in certain circumftances, as in 
fome meafure the acid fluoric gas retaing 
within itfelf the filiceous earth. 
C. Patrin has collected from travellers 
and the writings of natural philofophers 
who have {poken of volcanos, all the faéts 
which have appeared to {apport fome part 
of his fyitem. If this fyftem be not that 
of nature, itis thought to be, at leaft, that 
which approaches the neareft to it, 
Another queftion not lefs interefting by 
its connection with the general one con- 
cerning the point of paffage of brute fub- 
fiances into the flate of organized ones, was 
treated of by C. Ramond. 
We fometimes find the fnows which 
cover the higher hills tinged with a lively 
red; the matter that colours them burns 
with an odour refembling that which fe- 
veral vegetables yield. Sauffure, who often 
collected it on the Alps, has from the above 
property, and from the feafon when he took 
it up, viz. fummer, as alfo from the place 
where numerous vegetables were in Mower, 
been led to confider it as the farina from 
the ftamina of fome plant. : 
C, Ramond, who has alfo found it on the 
Pyrennées, having remarked that it was 
heavier than water; was led to fufpeét 
that it had a mineral origin, and he 
found in fact that it came from the decom- 
pofition of certain micas; this decompo- 
fition implies all the conditions obferyed 
by Sauffure, for C. Ramond-found thofe 
conditions were as neceflary to the Pyren- 
nées as tothe Alps. But how can a mi- 
neral fubftance thus take the chara&ter of 
an organic one? Does not this obferva- 
tion, fays C, Ramond, open a vatt field to 
the confideration of the means which na- 
~ture employs for imprinting an organic. 
form upon the molecules of inert matter, 
and for indemnifying or remunerating the 
races of the living, for the tribute-which 
diffolution pays to the dead. 
The production of native metals in the 
Interior of mines is alfo one of the objeéts 
which have drawn the attention of natura- 
lifts, and which have given birth toa mul- 
titude of fyftems, C. Gillet-Laumont 
exhibited by an experiment the manner by 
which that operation may be effected. 
He fhewed that by touching or rubbing 
with zinc or ifon the muriate of filver, i. e. 
the combination of the oxyde of filver with 
the acid of marine falt, that that precious 
metal immediately regains its purity and 
brightnefs by abandoning its acid to the 
metal touching it. Therefore the circum- 
ftances néceflary for this reduGtion, which 
. ingenuity 
