Rev. 0. Fisher — On the Formation of Mountains, 261 



He found that when moist many kinds of stone expanded more than 

 when dry. For instance, for 1° F. he obtained for 



Expansion. 



Sicilian White Marble { :oS613,Ty; 



Carrara Marble \ -00000662, moist, 



l^arrara marble ( -00000363, dry. 



T> , , , , ^ ., ( -00000532, moist. 



Peterhead red aramte j -00000498; dry. 



■ At 207° F. a rod of Greenstone, 23 inches long, contracted -^-iytli 

 part of an inch by drying alone, the moisture which was allowed to 

 evaporate being solely (as I understand the account) that absorbed 

 by hanging in the room for three months. 



Mr. Adie concluded that the average expansion of stone is very 

 nearly the same as that of cast iron at ordinary temperatures. 



Keferring to Mr. Babbage's speculations, he considers that 

 " little weight can be attached to such explanations of the great 

 operations of nature ; as there may be a vast difference between the 

 effect of heat quickly communicated to the small pieces of stone on 

 which we perform our experiments, and the necessarily slow diffu- 

 sion of the heat through such a depth of strata as " Babbage 

 '•' supposed ; " viz. five miles. ^ 



But I would go farther, and inquire whether the internal heat of 

 the earth would not produce contraction, rather than expansion ; at 

 least if it was sufficiently great to introduce metamorphism or any 

 chemical change. The phenomena of jointing, of mineral veins, and 

 of such faults as head to the downthrow, all point to a tendency in 

 rocks to contract when deeply buried. And in considering Captain 

 Hutton's theory, we must recollect that it is not the newly deposited 

 matter which he supposes to expand, but the rocks upon which it is 

 thrown down, which thereby become more or less hypogene. 



It will be noticed that in this paper I have made no allusion to 

 Mr. Mallet's new theory of the derivation of volcanic action from the 

 conversion of the mechanical work of crushing the shell into heat, 

 but have continued to regard lava as an extravasation of subjacent 

 superheated rocks. I am anxiously looking for the full statement of 

 that author's reasoning upon this question. But in the mean while I 

 must say that the arguments I have at present read are not to my 

 mind conclusive, first because I think his experiments do not run 

 parallel with the facts of nature, and, secondly, because the crushing 

 of the earth's crust must go on so slowly that the heat produced 

 must be dissipated before it can have accumulated to the requisite 

 amount. Other objections occur to me, but until the paper, as read 

 before the Eoyal Society, appears in full, it would be premature to 

 mention them. I have said thus much only because, in his otherwise 

 complimentary note ^ on my paper on " The elevation of mountains, 

 with a speculation on the origin of volcanic action," he has stated, 

 that my views on the latter subject do not appear to him equally 

 valid with my notions as to elevation. 



^ Trans. Roy. Soc. Edin., vol. xiii., p. 370. 



2 See Mallet's Palmieri's Vesuvius, lutroductory Sketch, p. 65, note. 



