12 MATTER, LIVING FORCE AND HEAT. 



" Descending from the planetary space and firmament to 

 the surface of our earth, we find a vast variety of phenomena 

 connected with the conversion of living force and heat into 

 one another, which speak in language which cannot be mis- 

 understood of the wisdom and beneficence of the Great 

 Architect of nature. The motion of air which we call wind 

 arises chiefly from the intense heat of the torrid zone com- 

 pared with the temperature of the temperate and frigid 

 zones. Here we have an instance of heat being converted 

 into the living force of currents of air. These currents of 

 air, in their progress across the sea, lift up its waves and 

 propel the ships ; whilst in passing across the land they 

 shake the trees and disturb every blade of grass. The 

 waves by their violent motion, the ships by their passage 

 through a resisting medium, and the trees by the rubbing 

 of their branches together and the friction of their leaves 

 against themselves and the air, each and all of them generate 

 heat equivalent to the diminution of the living force of the 

 air which they occasion. The heat thus restored may again 

 contribute to raise fresh currents of air ; and thus the 

 phenomena may be repeated in endless succession and 

 variety. 



" When we consider our own animal frames, ' fearfully 

 and wonderfully made,' we observe in the motion of our 

 limbs a continual conversion of heat into living force, which 

 may be either converted back again into heat or employed 

 in producing an attraction through space, as when a man 

 ascends a mountain. Indeed the phenomena of nature, 

 whether mechanical, chemical, or vital, consist almost 

 entirely in a continual conversion of attraction through 

 space, living force, and heat into one another. Thus it is 

 that order is maintained in the universe — nothing is 



