with reference to the Measure and Transfer' of Force. 331 



tion of this are as follows : — the motion of water moving with 

 velocity of 20 miles per second, converted into heat, would raise 

 its temperature about one million degrees ; iron about six mil- 

 lions. In about 10 feet depth of water there is as much heat 

 as in the superjacent atmosphere. The quantity of heat in a 

 cubic foot of iron is nearly the same as in a cubic foot of water. 

 Iron Y^o^^^ inch in thickness, heated six million degrees, is equi- 

 valent to 10 feet heated 500°, and 500° absolute is 40° on Eahr. 

 scale. The mean absolute temperature of the atmosphere is 

 250° when temperature at base is 40° F. 



2. Comparing the loork accomplished, or molecular square velocity 

 in globes of different radii and composed of the same kind of ho- 

 mogeneous matter, it is found to follow the ratio of the square of 

 radius. 



As an example, the earth may be compared with the sun in 

 this respect, supposing them of equal density and homogeneous. 

 If the temperature in descending the earth's radius increases 

 imiformly 1° in 50 feet, the mean temperature of its whole mass 

 would be about 100,000°. This is also nearly the mean tempera- 

 ture that would result from the work accomplished, if the matter 

 composing the earth had the specific heat of iron, the mean 

 square velocity being nearly the same as the square velocity of a 

 projectile moving in a circular orbit round the earth grazing its 

 surface. The sun's radius being about 100 times that of the earth, 

 its mean temperature would be 100,000 x 10,000, or one thou- 

 sand million degrees. The force of gravitation may thus be 

 viewed as the effective antecedent of the sun's heat. 



3. The capacity of a globe to generate force, increases in a 

 ratio that continually approaches the square of the radius of the 

 sphere within which its force of gravity is assumed to be limited, 

 and the capacity of different globes follows a ratio compounded of 

 the mass of the globe and the square of the cube root of the space 

 throughout which the action is supposed to be limited. 



4. The limiting sphere of the action of gravity being supposed 

 constant, and the size of the globe to vary, the capacity increases 

 as the surface of the globe. 



5. The capacity of different globes is the same if their force of 

 gravity is assumed to be limited within spheres that are in the in- 

 verse ratio of the globes respectively. 



§^- ... 



The force-generating faculty exists in space and is directed cen- 



tripetally. 



This is proved by the following considerations. 



The integral force-producing power of any body, however small, 



subject to the law of universal gravitation, is illimitable as space. 



Z2 



