C8 



SIXTH REPORT — 183G. 



Chemical 



theory 



slated. 



the heat of springs to the action of electricity. This mighty- 

 agent is doubtless concerned in many of the changes which go 

 on in rocks, but before we attribute to it the production of that 

 steady heat which resides in certain springs, we ought to con- 

 sider, what peculiar disposition of strata would be necessary to 

 give rise to it, what evidence there is of such a disposition exist- 

 ing, and why, if it exist at all, it be not more general, and thus 

 render the occurrence of hot springs less a local phaenomenon/ 



None of these questions having been entered upon by An-' 

 glada, it would be superfluous at present to proceed to a formal 

 consideration of his hypothesis. 



Neither need I dwell upon any such hypotheses, as are founded 

 on assumptions, which either seem contrary to acknowledged 

 principles of physics, or which would be rejected by the general 

 voice of men of science as absurd and fanciful. 



Thus I shall do no more than allude to the mode, in which 

 Aristotle somewhere accounts for the high temperature of springs, 

 by supposing, that as the figure of the earth is spherical, the 

 solar rays penetrating its substance, ought to meet in the centre, 

 as in the focus of a burning glass, and thus produce there an 

 intense degree of heat. 



Neither shall I labour to refute the idea of Keferstein, that 

 thermal springs are merely the result of, what he is pleased to 

 call, the respiratory process of the earth, resting, as that opinion 

 does, upon the assumption, that the globe itself is an animated 

 body, a position, which I am loth seriously to attack, not know- 

 ing in what precise sense his language is to be interpreted. 



But there remain two theories with respect to the origin of 

 thermal springs, that seem to deserve a more attentive con- 

 sideration . 



The former of these supposes them to arise from chemical 

 processes carried on within the earth, processes, however, 

 which possess nothing, in common with those witnessed on or 

 near the surface, except the circumstance of being attended with 

 an absorption of oxygen. 



If it be further demanded of the advocates of this theory, 

 what particidar chemical processes are alluded to, they will pro- 

 bably reply*, that a competent explanation of the phaenomena 



* They ought however carefully to distinguish, between that which appears 

 to be a direct inference from observed facts, and what at the most can ad- 

 vance no higher claim, than of being a plausible conjecture. The general 

 occurrence of volcanos in the neighbourhood of the sea, and the constant 

 disengagement of aqueous vapour and of sea-salt from their interior, are 

 facts, which establish in my mind a conviction, that water finds its way to 

 the seat of the igneous operations, almost as complete, as if I were myself an 



