161 



HARDWICKE'S SCIENCE-GOSSIP. 



includes among its members some distinguished 

 and well-known naturalists and botanists. Mr. T. 

 E. Amyot has a paper on the " Winfarthing Oak" 

 visited by the society last year, and a description of 

 which has already appeared in our columns. Mr. 

 H. G. Glasspoole contributes some biographical 

 memoirs of several Norwich botanists ; the hon. se- 

 cretary, Mr. Thomas Southwell, E.Z.S., a paper on 

 Mr. Marsham's " Indications of Spring"; the Earl 

 of Kimberley, a list of "Birds observed on the Kim- 

 berley Estate since 1871 " ; Mr. C. G. Barrett, an 

 essay on "The Wild Cattle at Chilliogbam " ; and 

 Mr. John Quinton, jun., a carefully-prepared series 

 of notes on the meteorological observations recorded 

 at Norwich during 1871. The part concludes; with 

 a lengthy and most valuable, carefully-arranged 

 list of flowering plants known to occur in Norfolk, 

 by Mr. H. D. Geldart, a well-known Norfolk bota- 

 nist. 



GEOLOGY. 



Remarks upon Mr. Mallet's Theory of Vol- 

 canic Energy. By the Rev. O. Fisher, M.A., 

 F.G.S.— Mr. Mallet's paper, read before the Royal 

 Society in 1872, was discussed by the author seriatim 

 as far as it seemed open to criticism. With respect 

 to the condition of the earth's interior, whether it 

 be rigid or not, Sir W. Thomson's arguments for 

 rigidity were referred to, and geological difficulties 

 in accepting his conclusions suggested. Mr. Mallet's 

 views regarding the formation of oceanic and con- 

 tinental areas, that they have on the whole occupied 

 nearly the same positions on the globe at all periods 

 from < he very first, were excepted to on the ground 

 that all continental areas with which we are ac- 

 quainted are formed of water-deposited rocks, and 

 that therefore those areas, must at some time have 

 been sea-bottoms ; and if these wide features have 

 not occupied the same positions which they now do 

 from the very first, Mr. Mallet's explanation fails, 

 that they were caused by unequal contraction when 

 the crust was i. first permanently formed and thin. 

 It was also shown that the theory of unequal radial 

 contraction cannot account for the difference of 

 elevation between continental and oceanic areas 

 upon reasonable assumptions. For if we consider 

 the crust to have been 100 miles thick (which 

 cannot be considered thin), and to have cooled from 

 1,000° F. to zero (a most extravagant supposition) 

 then, if the crust had contracted one-tenth more 

 beneath the oceanic area than it had done beneath 

 the continental, we should only get a depression 

 of one mile for the oceanic area, using Mr. Mallet's 

 mean coefficient of contraction. The main feature 

 of Mr. Mallet's theory was then discussed— viz., 

 that "the heat, from which terrestrial volcanic 



energy is at present derived, is produced locally 

 within the solid shell of our globe, by transforma- 

 tion of the mechanical work of compression or 

 crushing of portions of that shell, which compres- 

 sions and crushings are themselves produced by the 

 more rapid contraction by cooling of the hotter 

 material of the nucleus beneath that shell, and the 

 consequent more or less free descent of the shell 

 by gravitation, the vertical work of which is resolved 

 into tangential pressures and motion within the 

 shell." Mr. Mallet's mode of estimating the amount 

 of heat derivable from crushing a cubic foot of rock 

 was explained, and it was accepted as a postulate, 

 that the heat developed by crushing one cubic foot 

 of rock would be sufficient to fuse 010S of a cubic 

 foot of rock ; or, in other words, that it would 

 require nearly the heat developable by crushing 

 ten volumes to fuse one. Mr. Mallet considers 

 that the heat so developed may be localized. But 

 Mr. Fisher inquires why, since the work is distri- 

 buted equally with the crushing, the heat should 

 not be so also ; and since no cause can be assigned 

 why one portion of the crushed portion of rock 

 should be heated more than the rest, assumes 

 that all which is crushed must be heated equally. 

 In short, he is of opinion that if Mr. Mallet's 

 theory were true, the cubes experimented upon 

 ought to have been themselves fused. After paying 

 a just tribute of admiration to Mr. Mallet's elabo- 

 rate and highly important experiments upon the 

 fusion and subsequent contraction of slags, the 

 author remarked upon Mr. Mallet's estimate of the 

 probable contraction from cooling of the earth's 

 dimensions, showing that it had been based on 

 untenable assumptions. (The author of the paper, 

 however, holds that the contraction of the dimen- 

 sions of the globe has been greater than mere 

 cooling [will account for.) Upon the concluding 

 portions of Mr. Mallet's paper, in which he esti- 

 mates that the amount of energy afforded by the 

 crushing of the solid crust would be sufficient to 

 account for terrestrial vulcanicity, some strictures 

 were made ; but it was held that, if the maiu propo- 

 sition had not beeniproved, these calculations were 

 not of essential importance. 



"On the Occurrence of 'Eozoon Cana- 

 dense' at Cote St. Pierre."— This was the subject 

 of a paper read at a late meeting of the Geological 

 Society by Principal Dawson, of Canada. The 

 author commenced by describing the arrangement 

 and nature of the deposits containing Eozoon, at the 

 original locality of Cote St. Pierre, on the Ottawa 

 river. The Eozoal limestone is a thick band be- 

 tween the two great belts of gneiss which here form 

 the upper beds of the Lower Laurentian. Eozoon 

 is abundant only in one bed about 1 feet thick ; 

 but occasional specimens and fragments occur 

 throughout the band. The limestone contains bands 



