ON THE THEORIES OP ELEVATION AND EARTHQUAKES. 35 
narj- metal in a state of perfect fusion. In the latter case it is conceived that 
Kfht i dimensions retains its solidity, whereas in the case of flLd 
butVnitelHlT. “ targe portion of the mass consists of small 
mobiljt) IS mamtamed by the remaining portion of the mass intervoninir in a 
of^'tateS^elaT and consisting partly 
^ internal elastic vapours, which by their ascending movement kfen the 
'» a constant state nf^ebullition, and cL to 
itrS- than that of lava, immediately after it* 
wmark the influence which this constant movement of internal gases must 
m counteracting the tendency of the upper portion of iKa^ to 
« the loss of heat. It should 
x“rh“hey‘^'*"iVdT°"^^^ 
in fh ^ ® State of ebullition the more violent in pronortion 
Thus r f. ttirough which the vapoure ultimately Lcape 
be L f / lias descended to that which would 
De liie iemperaiure offmmn of the mass if it were placed in a statu of perfect 
arf'cIjablTSTx'IfrHi^^ vapours of volcanos 
Whe/J diseiuraopd f.. violence of volcanic eruption*. 
with which solhl m by the velocity 
projSton >'ock aswell as looser materials, frequently 
tea4 their livdrnatTH^^^'’ i a'ld "'liile existing within the fluid 
which they must ham distinctly firoved by the column of lava 
Diouth of an r>l wnt d “^PP^*** overflowing from the 
how enormoii* •» f increases with its temperature, we may conceive 
ducine at fonnpr volcanic gases may liave been capable of pro- 
S “I ^hat tlie leniperatum of the 
time. ^ considerably greater than at the present 
energetic at^o^^nf Y" /orcef.—The iniracdiatc cfleots of the more 
violent exoiosioiu forces are so generally exhibited in the form of 
be led lo gimnn 1 fK '**’without due consideration of the subject, 
character of mh.?^ r ^ *cdden and explosive action constituted an essential 
an So fon*;!^ . T- "'collcetcd. however, that to produce 
intensitv mu*i ho ”i necessary. In the first place, a force of great 
a force already almost iustantancously, or the re*Utance opposing 
on which tl.p r m^tanfanoougly removed; and aecoadly, the nias.s 
beina ^ to admit of a very great velocity 
Ss communicated to it. A force liLe that in ques- 
tesistatiep t ^ '**''*^*^ Ignition of an explosive compound, and the 
buKtinTof^h^'■"yf^'‘.^P°"**'‘■■ is as suddenly n-mnved by the 
would an i.vni "'‘th steam at a high tension ; but in neither case 
p ositifl bo the reault, unless the moss acted on were small. We 
• See ScTope • On Volcanos,' p. 19. 
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