'Theotyef the Earth,— Combujlm. 87, 



to caufe them to rife on one fide, while they become immerfed on the other, until at length 

 fome great fliock may reverfe them entirely, or caufe fome new mafles to rife from the 

 bottom of the fca. This will be, it may be faid, an hypothetical notion ; but it is a notion 

 wliich flicws that dc Vinci contemplated ihe caufe of the phenomenon in a way fufficier.ly 

 agreeable to the raechanifm of gravitation. No philofopher Cncc his time has yet thought 

 of a more fatisfntflory explanation *. . 



VI. Concerning flame and air. — Where flame is produced, a current of air takes place , 

 around, -which is neceffary to preferve arid augment the flame. The ftronger the motion of 

 the air, the more brilliant the flame and the greater the heat. Fire inceiTantly deftroys the 

 air which nourifhes it ; and it would produce a vacuum, if other air did not rufli in and 

 fill it. When the air is not in a ftate proper to receive the flame, neither flame nor any tcr- 

 reftrial or aerial animal can live. No animal can live in a place where flame cannot live. 



Smoke is produced in the centre of the flame of a candle, hecaufe the air which enters 

 into the compofition of the" flame cannot penetrate to its interior part.- It- is arrelted at the 

 furface of the flame, which it condenfes ; by becoming die aliment of the flame it is tranf-, 

 formed into it, and leaves a void fpace, which is fucceifively filled by other air. 

 , ♦ I mull confcfs that the difficulties of this theory do not apjxar to be removei cither by the observations of 

 the author or his learned comir.ci.taror. I apprehend that the hypothtfis requires or affertt, that I'ome natural 

 procefs flwuld take place to raife the land above the furface of the Water, which was originallv beneatli that 

 furface ; and the alTiinied ptincijjle is, that it iliall rife becaufe lighter than an eijaalmafi of water. The rpVcific 

 giavitics of miniral fubftancts are totally repugnant to this notion of floating continents, unlefs we fuppol'ethL-m 

 to be hoUow, which is by no means rendered prob-able to the required degree. Neither do we knoyv of any fafts • 

 which (hew that the longitudes and latitudes of places ott the fevcrai contments are liable to change, as mult bft 

 the cafe if each' continent were a feparate mafs capable of librating (Jn a comparatively narrow face of I'upport, 

 as fettns to he implitd in one pr.rt cf Profcilor \'<.nturi's ani;otation. It appears however to be well afccrtaincd, 

 that the fca has formerly furmounted the level of high, aod perhaps the. higheft mountains ; and from the re-' 

 gularity of difpofition which in many inftances is obfervablc (I'hilof. Journal, I. X21.) it may be doubted 

 whether the fliock of a comet (Philof. Journal, II. 41.) and the fuppofed change 6f the earth's -axis of rota-' 

 tion are fufficient to account for its fubfecjui-nt deprcilion. I think it"is fcarccly difputable, that the whole of 

 the folid mafs of the earth is connefted together, and that the fluid portion occupies the ca\itics to which it 

 can have accefs in this folid. - If we fufipofe tl)e globe of the earth to have been formerly enveloped 'by a fea, 

 whofc furface was between two and three niiles higher than the furface of theprefcnt ocean, or even much 

 lefs elevated, the finiple enquiry will be, what has become of it ? It, cannot have affumed the elafti'c ftate ; ■ for 

 we know the medium weight of the atmofphere, which correfponds with little more than a (hell of water co- 

 vering the earth to the depth of about thirty-three feet. We are therefore led to the following objefts of in- 

 veftigation : i. Is the earth folid throughout, or does it aflford natural cavities into which the water may, in 

 the courfe of ages, have found its way ? 2. As a vtry large part of the prefent furface of the earth has been 

 thrown up by the chemical procefs of volcanic combuftion, and thefe procelfes muft have left cavities beneath 

 the furface, it may become a matter of computation to determine the folid contents of volcanic product above 

 the prefent level of the fea, in order to afcertain the quantity of depreflion the fca would have fuffered on the 

 fuppofit'ion of its having fooner or later flowed into thofe cavities. 3. If, upon careful enquiry into thefe fafts, . 

 it (hould be afcertaincd, or rendered highly probable, that the primitive fea.has in a great meafure difappeared 

 by flowing into cavities in the folid mafs of the earth, would not the globe of the moon afford an inftance in . 

 confirmation of fucK a procefs ? For the obfcure parts of that globe which were at firft thought to be feas are 

 oblervcd to be cavities, probably the beds of ancient feas. It feems likely that the component parts of the 

 moon (whatever may be thofe of the. other planets) are nearly the.iime as of the earth. Yet its atmofphere 

 as well as itsfurface indicates a great warit.if not the tdtallbfence of tvater. Has it required lefs time for the 

 lunar fea to he abforbed ? — Much more might be faid : but on an objeft wlierc fafls arc wanting, and con- 

 jeftures plentiful, too much has^pcrhaps beuVfaid iflresdy. N. 



Mufchen- 



