292 ANNUAL OF SCIENTIFIC DISCOVERY. 



present equilibrium would be disturbed, and material!}- modified, by such 

 chaii^-s us have, from time to time, transpired in producing the formation 

 of mountain-chains and continents, and broad oceanic- depressions. This 

 principle can be illustrated by experiments. The earth may be represented 

 by a marble or small balloon falling in a vacuum. Modify the form of 

 these, however slightly, or add particles of matter to one hemisphere or the 

 other, and a partial rotation or change of equipoise is produced, turning 

 the heaviest diameter towards the earth. If this principle holds with a 

 marble, it will hold with the moon, and with the earth, and all planetary 

 masses moving toward the great central mass. 



" The second deduction is, that the earth was many miles larger in all its 

 diameters, when organic life lirst appeared in its shallow seas; and the 

 modus ogendi of physical causes was illustrated, by which have been pro- 

 duced the profound geological revolutions that have divided the creative 

 epochs. These causes lie in the play of the primal and central forces of the 

 planet attraction and repulsion by which periodic condensation and 

 expansion are effected (see 'Central Relations of the Sun and Earth/ 

 Annual of Scientific Discovery, 18-"8, p. 301); and all geological revolutions 

 arc direct results of the locomotion of the planet (a rocky, irregular shell, 

 with a plastic nucleus) in an orbit having radii vcctorcs of unequal lengths. 

 The igneous constitution of the globe, and its contraction in consequence 

 of the radiation of heat, as first suggested by Leibnitz, is sustained; but 

 the idea of slow and gradual puckering of the surface, maintained by 

 Cordier and modern geologists, is discarded. The permanent contraction 

 of the nucleus is produced by the escape of lava and heat from fissures and 

 volcanic orifices, and by the conversion of heat into magnetism and elec- 

 tricity, during its transmission through the crust, thus originating meta- 

 morphosis and crystallization, of primitive and superimposed rocks, in its 

 diffusion and passage to the surface. These local processes, together with 

 the periodic condensations arising from cosmical laws already referred to, 

 produce atmospheric or gaseous voids between the nucleus and the mun- 

 dane arch, which present possibilities, or absolute necessities, after long 

 intervals, for general convulsions of the globe, attended by sudden engulf- 

 ments, or subsidences of vast areas of its crust. Thus have the minor and 

 greater delineations of surface now observable been brought about. When 

 these catastrophes happen to the globe, the law of gravitation, as funda- 

 mentally stated above, immediately sways the planet into new polar rela- 

 tions to the plane of the ecliptic, and universal mutations of land, sea, 

 climate, isothermals, life, and of every other terrestrial and geographical 

 condition, follow. The facts on which were based these deductions were 

 traced from small to greater at length, and the geological sequences noted, 

 whatever the processes may have been which caused condensations of the 

 nucleus. Kilanea, a pit 800 feet deep and nine miles in circumference, on 

 the slope of Manna Roa in Hawaii, is a geological fact of remarkable sig- 

 nificance. Its walls are perpendicular; and Dr. Winslow, in his personal 

 explorations, has observed the debris of the roof projecting in a line of 

 ridges, from 50 to 150 feet high, above the sea of lava by which it had been 

 swallowed up. Thingvalla, in Iceland, graphically described of late by 

 Lord Dufferin, is another remarkable instance of engulfment; appearances 

 all indicating a sudden catastrophe, an area many miles in extent being 

 partially submerged beneath the sea. Various sudden submergencies of 

 small areas, within recent epochs, for instance, that of the site of old 



