GENERAL LAWS OF CALORIC. 13 



bodies, is directly in proportion to the amount of 

 caloric around their particles : 



2. That all molecular motions, whether centri- 

 fugal or centripetal, may be resolved into the law 



by ivhich caloric repels its own particles, and at- 

 tracts those of ponderable matter, with forces that 

 vary inversely as the squares of the distance : 



3. That the quantity of motion in the world, 

 whether mechanical, chemical, or vital, is in pro- 

 portion to the mean temperature of different lati- 

 tudes, ceteris paribus, and diminishes from the 

 equator to the poles : 



4. That the centrifugal force by which planets 

 are impelled through their orbits, is directly in pro- 

 portion to the heating power of the sun ; and like 

 gravitation, is inversely as the squares of the dis- 

 tance : 



5. That the aggregate vital energy of animals, 

 and the dev elopement of their organization, are ex- 



ment of the particles of ice, glass, quartz, and other crystals, is 

 disturbed by unequal pressure, or unequal expansion by caloric, the 

 rays of light are transmitted imperfectly : and if their symmetrical 

 structure be broken down or deranged, as when they are reduced 

 to powder, their power of transmitting light is so far destroyed, 

 that they are rendered opaque. Sir Isaac Newton supposed that 

 opacity was owing to the largeness, and transparency to the 

 smallness of the particles and intervening pores of bodies. (Optics, 

 B. ii. p. 235.) But many salts, rocks, and metals, are transparent 

 when dissolved in water and the strong acids, although their par- 

 ticles are much larger than those of common ink and many other 

 bodies which are black and opaque. 



