372 Analysis of Scientific Books. 



garnet, were produced by the " capricious play of the forces of 

 chemical affinity." i 



The theory of gneiss is, however, much more unquestionably 

 original. We must imagine, what in fact has been proved long 

 ago in the first part of the work, a general intumescence of an 

 intensely heated bed of granite, forming the original surface of 

 the globe, succeeded by a period in which the predominance was 

 acquired by the repressive force, occasioned by the condensation 

 of the waters on its surface, and the deposition of sedimental 

 strata forming the transition series. This " simply, at once," 

 explains the lamellar structure of the gneiss formation. " And 

 this structure may have been subsequently increased by the 

 friction of the different laminae against one another^ as they were 

 urged forwards in the direction of their plane surfaces towards the 

 orifice of protrusion, along with the expanding granite beneath ; 

 the laminae being elongated, and the crystals forced to arrange 

 themselves in the direction of the movement." 



Hence the author proceeds to give what he calls a " conjectural 

 rough sketch of the theory of the globe, " which, with the exception 

 of an appendix, terminates the present volume. We were not 

 wrong, then, in considering all that we have already quoted as 

 matter utterly new, since he concludes, that however imperfect 

 this theory may be, it is deduced from the views which he has 

 laid down, and is " more accordant with the general and constant 

 processes of nature than any other which the spirit of geological 

 inquiry has yet started." 



The mass of the globe, or at least its external zone to a con- 

 siderable depth, was originally of a granitic composition with a 

 very large grain. 



On reaching its actual orbit, or before, " it enjoyed a great 

 diminution" of the pressure which had previously crystallized, or 

 preserved it in a state of crystallization, at an intense tempe- 

 rature, perhaps as an integrant part of the sun. 



Part of its atmosphere was lost in its passage from the sun, on 

 the principle of a comet's tail ; and the remainder formed the 

 present atmosphere and the ocean, or the main reservoir of su- 

 perficial waters. 



The rotatory motion and the liquefaction of the surface pro- 

 duced the oblate form. And as the " process of expansion pro- 

 ceeded in depth," the original granite beds were liquefied ; " the 

 crystals being merged in the elastic vehicle produced by the va- 

 porization of the water contained between the laminae." And as 

 the superior pressure forced it out, a quantity of aqueous vapour 

 was produced on the surface of the globe, while its expansion 

 lowering its temperature, it fell back again and produced water. 



Thus there were alternations, and consequently rain, and tor* 



