G. Poulett-Scrope — Source of Volcanic Heat. 343 



opinions the very reverse of those so pertinaciously fastened upon 

 me by Mr. Mallet. And were I to assert that he, " in his writings " 

 upon earthquakes, had attributed them to the oscillations of an 

 extremely thin crust over a liquid nucleus, I should not misrepre- 

 sent his views more completely than he has misrepresented mine 

 upon the source of volcanic energy. I venture, then, to put the 

 question to the scientific world, whether any reputation can be 

 sscure, if it be allowable for a writer, publishing his work from the 

 vantage-ground of the Eoyal Society's Philosophical Transactions, 

 and with the object of maintaining a theorj^ of his own, to impute 

 to another writer on the subject opinions which he has not only not 

 enunciated, but which he has in his " systematic works," as well as 

 in others, disavowed in the emphatic and conspicuous manner em- 

 ployed by me in the passages above referred to concerning the views 

 " saddled upon me " by Mr. Mallet ? And I ask, further, when the 

 imputation has been denied, is it consistent with the courtesy and 

 honourable conduct usual among gentlemen that it should be re- 

 peated again and again, when it would have been so easy to refer 

 to the work in which its incorrectness, to use no stronger word, lies 

 patent to the most cursory glance ? 



But Mr. Mallet has a peculiar way of conducting a scientific con- 

 troversy, as will be evident to all who have looked into his paper, 

 where, to take one example, in the compass of half a dozen lines 

 (p. 152), he expresses his contempt for Mr. Hopkins's " fiery lakes," 

 as he styles them, in the following choice epithets: "a lame and 

 gratuitous hypothesis," " feeble and unconvincing," " most impro- 

 bable," " erroneous and imtenable," " inherently improbable," — 

 epithets which, as in other instances that might be adduced,^ Mr. 

 Mallet seems to consider a sufficient and complete refutation of 

 the opinions he has thus denounced. True it is that Mr. Hopkins's 

 A'iews are wholly at variance with Mr. Mallet's rock-crushiug 

 derivation of volcanic heat, and therefore to be " put down." But 

 it is not unimportant to observe that the former has the siipport of 

 Professors Dana and Sterry Hunt, dynamical geologists of far higher 

 authority than Mr. Mallet.^' 



One word upon a passage in Mr. Mallet's last letter in the Geol. 

 Mag. for July, p. 332, which professes to be an argument against my 

 view of the derivation of volcanic heat from "a rise in geothermal 

 temperature produced by deposition of sediment," namely, that " no 



^ See for another example p. 133 of Reply, etc. (Geol. Mag. for March, 1874), 

 in which Mr. Mallet, after declaring that " the limits -within -which the fusing 

 temperature of rocks can be raised or lo-wered by difference of pressure are unques- 

 tionably too small to play any important part in geologic phenomena," adds ; 

 " The notion -was seized upon by Hopkins as offering some feeble support to his wild 

 hypothesis of subterranean lava-lakes." And lower, in the same page, he characterizes 

 my "notion" that water existed in the rock-matter from which lava is formed pre- 

 viously to its fusion, as " wholly untenable," and again, three lines further on, as 

 "utterly untenable" — a favourite epithet with Mr. Mallet, and employed by him, 

 here as elsewhere, in lieu of argument. 



^ See Silliman's Journal for July, 1873, p. 10, and the same work for April, 1873, 

 pp. 264-7. 



