No, 144.) 385 



the imagination, a perpetual motion, the further we get from it. 

 At the bottom lies the great equation of the equality of the forces 

 to the resistances, and the intervention of the least machinery in- 

 creases the resistances^ . 



But the surface of the earth is a great machine in perpetual 

 motion ; winds are blowing, clouds are moving and rivers are 

 running continually. It does not explain these phenomena of 

 motion, to attribute them to gravity. Gravity would settle every 

 thing in a short time and leave all things as motionless and silent 

 as the vault of the fixed stars. Gravity is only the recoil of the 

 Spring, the running down of the clock work. Gravity must be 

 disturbed before it can produce any' motion, and that disturbing 

 power is the sun. The force that a cloud exerts in rising, is a 

 force given it by the sun. The force that rain exerts in falling, 

 is a reproduction of the power that it took to raise it, and the 

 force that a river exerts as it rolls down into the sea, is but the 

 same force that was spent in wafting it in clouds, up to the tops 

 of the mountains. We must all the time keep returning to the 

 sun as a source of power. 



The motions of the earth on its axis and in its orbit must be 

 subject to the same course of reasoning. We have been taught 

 to believe, that it continued to move, because there is nothing to 

 stop it. If it were set to do any work, just so much of the velo- 

 city would be destroyed, and by just so much would the diameter 

 of its orbit be lessened and the year be shortened. This is actually 

 happening with the years of some comets; it is generally suppo- 

 sed, because they are impeded by ether. Now, it is difficult to 

 account for the tides by any chemical action of the sun; they are 

 generally attributed to mechanical influences, and it is very pro- 

 bable, that we may yet discover, that some heavenly body is de- 

 layed in its motion, by being tasked to rock our oceans. This 

 delaying force would amount to so little, when compared with the 

 momentum of a planet, that it may as yet have been unappreciable. 



Dr. Draper has shown how the chemical forces of the sun- 

 beam are expended on the green matter of the leaf, in reducing a 

 srtain and definite am( 

 [Assembly, No. 144.] 



