36G Dr Daubeny's Speculations as to the 



What may Lave been the nature of the processes which have brought 

 about the disengagement of these gases, I have discussed at full in ni}' 

 work on Volcanos,* and in other subsequent publications. At present, I 

 will only remark that, whilst the evolution of carbonic acid indicates per- 

 haps nothing more than the operation of subterranean heat, the escape of 

 atmospheric air, deprived of a portion of its oxygen, seems to imply that 

 this heat originates in internal combustion, by which oxygen is absorbed ; 

 and the disengagement of ammonia may lead us to presume that this 

 combustion is connected with the decomposition of water. 



The latter inference appears to be unavoidable, when we recollect that 

 ammonia is a compound of nitrogen and hydrogen, and that the only sub- 

 stance which can well be supposed to supply the latter element within 

 the interior of the globe is water, which we also know to be abundantly 

 present. 



Water is readily decomposed by several of those bodies which, in an 

 oxidized condition, constitute the various products of a volcanic eruption, 

 and hence it seems not illogical to consider its action upon the bases of 

 the earths and alkalies, which may still exist in the interior of the globe, 

 as the primtim mobile of such phenomena. 



What, however, I am principally anxious on the present occasion to 

 point out, is the discovery of a final cause, for the extrication of those 

 gases, which I and others, in our examination of volcanos, have so fre- 

 quently been led to remark ; as this alone renders it probable that the 

 phenomenon in question is one not of local or incidental occurrence, but 

 that it has gone on from the beginning of time, on that gigantic scale 

 which is consistent with the grandeur of those operations that have oc- 

 casioned it, and is adequate to those equally extensive uses that we have 

 ventured to assign to its agency. 



Thus much, at least, seems clear, namely, that when we attribute, — as 

 many without due reflection appear to do — the nitrogen which plants absorb 

 to the products of the decomposition of animals, whilst these very ani- 

 mals are supposed to have obtained their nitrogen from the vegetable food 

 on which they had themselves subsisted, we are reasoning in a vicious 

 circle, and can hardly help being brought to the admission, that if plants 

 are allowed to have multiplied and increased by any natural causes, they 

 must at one time have obtained their food from inorganic matter exclu- 

 sively ; and moreover, that, even at present, no increase to the common 

 stock of these elements, which is treasured up already in two organic 

 kingdoms of nature, cm take place, except it be furnished from the same 

 identical source. 



In conclusion, then, 1 may remark, that in balancing the rival preten- 

 sions of the two theories, by the aid of which it has been attempted to 

 explain the origin of volcanos, we cannot be justified in leaving out of 

 the account phenomena, which, like that of the disengagement of ammo- 

 nia, are of such general occurrence, and appear subservient to such im- 



* Description of Active and Extinct Volcano?. London, 1826. 



