Ixxii PKOCEEDINGS OP THE GEOLOGICAL SOCIETY. 



The serpentine of Baldissero in Piedmont gave the most characteristic 

 product — one, indeed, identical with that obtained from Iherzolite* ; 

 and although certain other silicates were formed, they are quite 

 subordinate to the two above-named minerals. 



Sundry authors have already pointed out this relationship ; and it 

 has been suggested that serpentine has been produced from peridote 

 rock by the addition of some silica, and of water forming a hydrate. 

 M. Daubree suggests, however, that there is no occasion to conclude 

 that such a change took place near the surface, for the serpen- 

 tine may in many cases have been protruded, after acquiring at great 

 jdepth the water which it still contains. The great readiness, too, 

 with which the melted substance was transformed into less basic 

 silicates, seems to account for the frequent association of these rocks 

 with euphotide, with greenstones, &c. 



If we now compare the fused serpentines with the meteorites, it 

 appears on experiment that when they have been melted in a lining 

 of carbon, grains of iron get separated which prove to contain nickel. 

 Moreover both old analyses and abundant observations tell us that 

 in very many and distinct regions of the earth chromium, as chromate 

 of iron, is constantly associated with serpentine, and scarcely ever 

 absent from meteorites. And although serpentine, on account of its 

 hydrated condition, seems less comparable with the meteorites than 

 peridote and Iherzolite, yet it is a curious exception that certain rare 

 .carbonaceous meteorites (those of Bokkeveld at the Cape, 1838, of 

 Kaba in Hungary, 1857, and of Orgueil) contain a hydrous silicate, 

 referred by Wohler to a variety akin to serpentine. 



Fortified by the striking analogies which arise from his laboratory 

 experiments, M. Daubree has ventured to speculate on the original 

 constitution of the crust of the earth. After recalling to us the 

 theory of Davy, that the metals of the earths and alkalies enclosed 

 in the interior of the globe may produce the phenomena of volcanos 

 by oxidation in contact with water, he refers to its application by 

 geologists to the origin of the stony crust. Our lamented friend Sir 

 Henry De la Bechef (" dont I'esprit savait embrasser toutes les 

 grandes questions de la Geologic," as Daubree truly puts it) was one 

 of the first to point out how that crust is made up in great part of 

 oxides of the metals which have the strongest avidity for oxygen, 

 viz, potassium, sodium, calcium, magnesium, and aluminium, and 

 how the very water of the ocean may be considered the result of the 

 combustion of the hj^drogen in the midst of the general oxidation. 



These hypothetical views appear to be supported by the synthe- 

 tical experiments; for we may conclude that the peridotic rocks of 

 our globe had an origin analogous to that of the similar substances of 

 the meteorites, and that in fact they are the most direct products of a 

 scorification which took place at an enormously remote epoch. 



To explain the meaning of the term scorification, we are reminded 

 that if a bath of impure iron be kept in fusion, in contact with the 



^^ The melted substance, as in the former experiments, would sometimes take 

 up other material, and especially silica, from the sides of the crucible. 

 t Eesearches in Theoretical Geology, 1834, chap. 7. 



