194 Chi EanJiqitakcs; 



Eiost ordiuary operatious of nature, and to be necessary to preserve that- 

 universal order which prevails throughout the planetary system. Although 

 according to the strict rules of science-, we are not permitted to reason, except 

 upon facts actually observed, yet to a certain extent, we may indulge in 

 conjectural speculations. These, although they often lead to error, yet 

 sometimes guide to truth. 



Granting that earthquakes may be caused by the occasional fissuring of 

 rocks in the subterranean depths, it has next to be shewn by what force 

 these fractures have been, and still are produced.. Upon this point also w^e 

 have no knowledge from direct observation. If the interior be subject to 

 an intense heat sufficient to melt the hardest rocks, then it must be in a 

 jBuid or viscid state. The facts that as we descend, the teimperature increases 

 — that wherever there are openings through the surface, melted matter oozes 

 cut, and that great elevations and depressions of land which could not well 

 occur, were the earth solid like a cannon ball, have been common in all ages, 

 seem to demonstrate that ; not only is the interior in a fluid state, but that 

 the exterior crust is of no gi-eat thickness^ Many mathematicians are of a 

 contrary opinion, but notwithstanding all manner of calculations, the facts 

 still remain. We do not believe that the myraids of short flexures to be 

 seen in the Laurentian rocks of Canada could have been produced upon the 

 surface of a planet, solid through to the centre, or even to the depth of twenty 

 miles. And if such be the structure of the interior, then any fluctuations of 

 the viscid mass within would cause movements of the exterior, elevating 

 some portions — depressing others — straining the rocky covering, and now 

 and then rending it asunder. The following passage from Sir John- 

 Herschel's writings, although not much regarded by Geologists, has always 

 appeared to us to contain within it the explanation of nearly all the pheno- 

 mena of earthquakes and volcanoes. '\^Tiile upon the subject of the consti- 

 tution of the Sun, he says : " The Sun's rays are the ultimate sources of almost 

 every motion which takes place on the surface of the earth.. By its heat are 

 produced all winds, and those distm-bances in the electric equilibrium of the 

 atmosphere which give rise to the phenomena of terrestrial magnetism. By 

 their vivifying action vegetables are elaborated from inorganic matter, and 

 become, in their turn, the support of animals and of man, and the sources of 

 those great deposits of dynamical efficiency which are laid up for human use- 

 in our coal strata. By them the waters of the sea are made to circulate in 

 vapour through the air, and irrigate the land, producing springs and rivers. 

 By them are produced all disturbance of the chemical equilibrium of th» 

 elements of nature, which, by a series of compositions and decompositions, 

 give rise to new products and originate a transfer of materials.. Even the 

 slow degradation of the solid constituents of the surface, in which its chief 

 geological changes consist, and^ their diffusion among the waters of the ocean, 

 are entirely due to the abrasion of the wind, rain and tides, which latter, 

 however, are only in part the effect of solai' influence and the alternate 

 action of the seasons ; and when we consider the immense transfer of matter 

 so produced, the increase of pressure over large spaces iu the bed of the 



