Researches in the Theory and Calculus of Operations. 335 



which thereupon take up a new arrangement, soon to be 

 changed by the accumulating effects and varying action of 

 the Sun in its movement, and by the different reactions of 

 successively encountered forces of surrounding media. 

 Every combination and change is identified with movement 

 in space, an advance from a lower to a higher region, in 

 the course of which new forms of force are encountered. 



" Nursed by warm sunbeams in primeval caves, 

 " Organic life began beneath the waves." 



Erasmus Darwin. 



Within the pristine element, water, the external forces 

 to be encountered by the growing atoms are, the still water 

 itself and air mingled therewith, the former changing in 

 density according to depth, and changing in temperature 

 m in different regions ; the permeating rays of light according 

 to the season ; the resistance opposed to floating motions 

 by the rocks and shores ; the currents and occasional waves, 

 and the molecular vibrations of the fluids, etc. The possible 

 developments in water therefore will be, the growth of scales, 

 shell, or other dermoid tegument, as protection against the 

 surrounding medium; the formation of gills, by the trans- 

 fusion of the vital air; the development of eyes, by the 

 action of the luminous force; the projection of limbs, 

 broght out by reaction against concussions on rocks, etc., 

 or of tins from the pushing of waves; the formation of ears, 

 initiated by molecular vibration occurring in the surround- 

 ing fluid. 



Raised from the aqueous to the aerial element and placed 

 upon terra firma, the changed conditions necessitate a mo- 

 dified dermoid action to meet the surrounding atmospheric 

 medium ; an enlarged capacity of lung, to entertain a greater 

 allowance of oxygen; a more delicate and elaborate de- 

 velopment of eye, called forth by the greater degree of lu- 

 ninosity, and of ear, corresponding to the livlier aerial 



