166 PHYSICAL GEOIOGT. 



HiTTTON', Capt. F. "W". On the formation of Mountains. Geol. Mag. 

 dec. 2, vol. i. p. 22. 



A reply to the Ilev. 0. Pisher's criticisms on the author's paper in 

 vol. X. p. 166. 



Jespeksen-, M. Creeps. Geol. Mag. dec. 2, vol. i. p. 238. 



Inquires whether earthquakes, igneous ejections, and elevation of 

 mountains may not be caused by subsidences, analogous to '^ creeps," 

 caused by the removal of underground masses of rock by percolating 

 water. A. H. G. 



Mallet, Eobert. In reply to Mr. Scrope's observations on Mr. 

 Mallet's Theory of Yolcanic Energy (p. 28 of same vol.). Geol. 

 Mag. dec. 2, vol. i. pp. 127 & 189. 



Explains that he does not commit himself to any opinion about the 

 state of the earth's interior further than that it is hotter than the ex- 

 terior, and that the heat lost by radiation gives rise to mechanical work, 

 part of which is transformed into heat, which is the cause of volcanic 

 action. He believes that with a thin crust and a liquid nucleus no open 

 fissures could penetrate through the crust, and that if they did the melted 

 matter would not rise through them. He points out that there are vari- 

 ations in the rate of increase of underground temperature which cannot 

 be accounted for by conductivity alone, but which his theory ex- 

 plains. He maintains the approximate accuracy of the data on which 

 he has based his numerical calculations, and concludes by pointing out 

 that Mr. Scrope admits some degree of squeezing and crushing of rocks 

 by internal movements, which, he says, amounts to an admission of his 

 theory. The controversy is continued on pp. 332 and 478. A. H. G. 



. Additions to the paper on Yolcanic Energy &c. (Phil. Trans. 



1873, p. 147). Proc. Boy. Soc. vol. xxiii. p. 328. 



Calculations have been made, on certain allowable suppositions, as 

 to the amount the solid shell of the earth must be crushed to admit of 

 the shell following down on the more rapidly contracting nucleus. 

 The annual amount of contraction of the globe is estimated at little 

 more than 3-5 inches on the mean radius for the last 5000 years, sup- 

 posing the contraction to have been uniform during that time. . This 

 quantity is too small to be capable of having produced, during the last 

 2000 years, any sensible effect on the length of the day. A. H. G. 



. On the Mechanism of Stromboli. Proc. Eoy. Soc. vol. xxiii. 



p. 496. 



Comments on the rhythmical character of the outbursts, which has 

 not received satisfactory explanation, but may be accounted for by 

 supposing that we have in Stromboli the same succession of phenomena 

 as those of a geyser, superadded to some of those of a volcanic vent of 

 feeble but long-continued activity. The explanation could not be made 

 intelligible without a figure. A. H. G. 



MoEEis, Prof. J. Landslips and sinkings in Cheshire. Geol. Mag. 

 dec. 2, vol. i. pp. 259-261. [Notice of a Report, by J. Dickinson, 

 presented to the House of Commons 1873.] 



