182 E A R T II. 
globe, of the intricate compound of the liquid called flea- 
water, and of the no lefs intricate atfemblage of elaflic 
fluids which now forms our atmofphere, I think you will 
not oppofe to it, our incapacity of producing fuch a li¬ 
quid. I have faid before, that we are too little advanced 
in general, precife, and vvell-direfted, obfervations, to 
determine exactly thofe phenomena: it will be then, par¬ 
ticularly, to eftablifh, from a number of new obferva¬ 
tions, the charadleriftic facls, from which I have drawn 
thefe out-lines. I come now to your fecond hypothefis, 
in the examination of which, new proof will occur of 
what I have hitherto {fated. 
2d. Hyp. The fame heat that has melted our folid 
Jlrata has been capable of raifing them. —According to this 
hypothefis, when our frata had been produced by a pre¬ 
tended fujion , they were raifed by the fame heat that had 
melted them. On this I mud quote your own words: 
“ There has been, you fay, p. 263, an extreme degree 
of heat below the Jlrata formed at the bottom of the tea ; 
and this is prccifely the afiion of a power required for the 
elevation of thofe healed bodies into a higher place.” In 
explanation of this, I rind only thefe few words, which 
are in the fame paragraph : “ The power of heat for ex¬ 
panding bodies, is, fo far as we know, unlimited.” Being 
deprived of more explanation from you, I muff fuppofe, 
what only can give the idea of an adequate power of that 
kind; and this would be, the hidden and copious pro¬ 
duction of fome elaflic fluid-, but, fir, if you had taken 
notice of what I have faid, refpedting that idea, in my 
Letters on the Theory of the Earth, you would not have 
renewed that ancient hypothefis. When that fuppofed 
operation took place, the (Irata which were to form our 
continents , were either in their fird date of fujion, or confo- 
lidaied by cooling. In the firfi cafe, the expanding fluid 
would have raifed an immenfe bubble, the middle of which 
would have foon burfl, by the foft matter falling down 
its fides; or if the Jlrata had been before ccnfohdated, 
they would have been broken to pieces: and in both 
cafes, the elaflic fluid having made its efcape, the raifed 
materials would have funk again. To prove that our 
continents have been raifed by the expanfion of fome fub- 
ftance below them, you fay, p. 271, “ One thing is de- 
monftrable, from the infpection of the veins and their 
contents ; this is the fucceflive irruptions of thofe fluid 
fubftances, breaking the folid bodies which they met, and 
floating thefe fragments of the broken bodies in the vein.” 
This is unintelligible to me: for you here fuppofe a very 
denfe liquid, lince it is to float fragments oi flours-, but 
fuch a tubflance cannot afford the fmalleft idea of an ex¬ 
panfion fuch as you want it: however, let us go on. “ It 
is very common, you fay, to fee three fucceflive Jeries of 
thofe operations; and all thefe may be perceived in a 
fm'all fragment of done, which a man of Jcience may exa¬ 
mine in his clq/ct often better than defcendifig the mines ...” 
But fird, if an expanded matter had broken through our 
Jlrata, would it have only filled up the fiffures ? would 
it not have rufhed out in torrents? However, no exu¬ 
berance of the fubftances of veins is found any where. On 
the other hand, you give afterwards lavas as a proof of 
thofe irruptions of melted fubflances: we ought then to find 
it in veins-, and none of them contain lava. Thus, the 
phenomenon of bur veins, which you thought fo favour¬ 
able to your hypothefis, is abfolutely againd it. You do 
not fay what is that fmall fragment offlone which is to in¬ 
form a man of fcience ; but I have defcaided into various 
mines, and there I have feen a variety of quite diderent 
fubdances laid over one another, either regularly or pro- 
mifeuoudy. Many forts of metallic ores form their didinft 
layers, between other mineral fubdances; and en¬ 
tirely different from each other are found, at but a little 
didance, in the fame ridges of mountains. Thefe, and 
many other circumdances, which you would have feen 
better in the mines, than in a fmallfragment of flone, would 
have led you to think, that if a liquidfubflance had been 
forced, from fome furnace, through our Jlrata, and had 
filled up the fiffures, it would have been an homogeneous 
fubdance, as lavas are, and not fuch a variety of diltindl 
fubdances. 
In order to determine the power exerted in your fup¬ 
pofed operation, you fay, p. 271, “ Let us confider what 
power could be required to force up, from the mod un¬ 
fathomable depth of the ocean, to the Andes or the Alps , 
a column of fluid metal or flone s: this power cannot be mrrCh 
lefs than that required to elevate the highefl land upon the 
globe.” As you allude afterwards to the columns of lava 
forced up to the top of high volcanos, I will apply to them 
your argument, for fhortnefs fake; a-nd I Avail fuppofe, 
that the principle on which you depend is, that a liquid 
column, whatever be its diameter, preffes upon its bafe, 
in proportion to its height: but, fir, if the vaults, a'gainfl 
which the liquid column preffes upwards, were to give way, 
the column would indantly fubfide ; and in the cafe you 
want to explain, the vaults againd which th c power was to 
exert itfelf were our whole continents-, which were to be 
raifed, and fo to give way. I do not think that you have 
given a fufficient degree of attention to that pretended 
analogy. You quote an example of fuch an operation; 
and, as the cafe is real, the above argument will thereby 
be exemplified. “ It mud be evident, you fay, p. 273, 
that in the cafe of the new-ifland near Santorini, had the 
expanfwe power been retained, indead of being difeharged, 
much more land might have been raifed above the level 
of the ocean.” My propofition is, that no land can be 
raifed in that manner, becaufe the expanfwe power mud 
be difeharged: and this is an indance of it; for no band 
was raifed. I have examined that event, with that of a 
new hill formed near Naples: in both, the dijeharge of the 
power was the fird and condant fymptom obferved ; and 
the blad itfelf was the caufe of the new exuberances 
formed on the furface of the ground: not by'railing a 
land, by which mud be underdood whole Jlrata, but by 
heaping up melted and broken materials. Thefe, in 
fliort, were only two volcanic cones, fimilar to all thofe 
which, in the 1 fea, form iflands and mountains on our con¬ 
tinents. s 
The common mole-hills give us a clear and precife idea of 
the mechanic operations by which fuch heaps are formed 
upon the folid ground-, thofe operations being of the fame 
general kind, from the little difregarded excrefcence made 
by the mole, up to the Etna, and to the volcanic cones of the 
Andes. A fird opening is made at the furface of the ground, 
by the power which is to perform the whole mechanic 
operation. The ground afterwards is undermined, and 
the power throws-up the loofe materials, which accumulate 
round the opening. In the formation of a mole-hill, the 
whole operation is mechanic ; the animal is, in the mean 
time, the miner and the hcaptr. In the formation of vol¬ 
canic cones, there are alfo chemical operations, by which, 
fird, a great heat is produced, that melts certain mineral 
fubdances,which I have fome reafons for fuppofing to 
lie under all the frata: at the fame time, elaflic fluids, 
efpecially fleam, are produced; and thefe form the me¬ 
chanic power. The fird effect of that power is, to bin d 
the Jlrata above. If, then, the melted matter obdrudls the 
paflage to thofe condantly forming elaflic fluids, they force 
it up through the opening, mixed with maffes of the broken 
Jlrata: whence the accumulation of thofe materials, on 
the outfide, in the uniform fhape of a cone. The condant 
rudiing out of the elaflic fluids, keeps a channel open in 
the axis of the cone, through which, from time to time, 
are forced up lavas, either compact, or frothy ; thefe 
are the pumice Jlones. At other times, when the liquid 
matter is not fufficient to fill up the channel, the b-lajl 
burds through it, and drives along, even at a great height 
above the crater, fliowers of red-hot maffes of that liquid ; 
thefe are the volcanic cinders. When thofe fbowers are 
thrown up from a great depth, part of the snelted matter 
confolidates againd the fides of the channel in its cooler 
parts. 
