■±1 [Chase, 



The Limiting Constant of Gravitation. By Pliny E. Chase. 

 {Read before the American Philosophical Society, October 18, 1878.) 



Newton and Lesage both thought that gravitation might be due to some 

 action of an aether or "sethereal spirit." If such supposed action is uniform 

 it should be capable of representation by some uniform or constant value, 

 toward which planetary or gravitating motion should constantly tend. 



Faraday sought in vain to find such a value, and his want of success led 

 htm to the belief that the "correlation of forces" could not include the 

 force of gravity. It is true that a kind of constancy is observable in bodies 

 at rest, and another kind in circular orbits ; but if the distance from the 

 principal center is changed, the former varies inversely as the square of 

 the distance, the latter inversely as the square root of the distance. In- 

 asmuch as there is no known limit of possible density, there is no obvious 

 limit to the possible velocity of gravitating motion. 



My various investigations have shown that heat, actinism, kinetic laws, 

 spectral lines, t lie arrangement and masses of planets, interstellar nodes, 

 barometric fluctuations, centers of inertia, terrestrial magnetism, chemical 

 combinations, and the aggregation or dissociation of stellar systems, all 

 point to the velocity of light as a limiting constant. Weber, Kohlrausch 

 and Maxwell having found a like pointing, in the relations which exist 

 between electro-static and electro-dynamic phenomena, it seems probable 

 that the goal of Faraday's search may also have been the velocity of light, 

 and that such velocity is the fundamental basis of universal correlation. 



I have already pointed out three methods of approximation to the limit : 

 1, by the tendency towards equality in planetary revolution and in the 

 mean moment of solar inertia of rotation ; 2, by the tendency to equality 

 between mean radial oscillatory velocity and the velocity which marks the 

 limit between complete solar dissociation and incipient nucleal aggrega- 

 tion ; 3, by the tendency to uniformity in dissociative velocity at each of 

 the three principal centres of nebular condensation in the solar system. 



Against the first of these methods the objection has been urged that it 

 supposes the sun to be homogeneous. The validity of this criticism cannot 

 be determined until the problem has been subjected to a rigid mathematical 

 analysis. If such analysis should hereafter show that the objection is well 

 taken, it may be found that the sun is more homogeneous than the dense 

 planets, and sufficiently so to satisfy all the requirements of the method. 

 Draper's recent photograph of the corona indicates a diameter twice as 

 great as that of the sun. This is in exact accordance with the supposed 

 gaseous nature of the sun, and, consequently, with its homogeneity, as well 

 as with the relations which I have pointed out between Jupiter's mass and 

 position. 



Some have thought the second method faulty, because it involves a con- 

 sideration of hypothetical conditions of nebular condensation, such as are 

 inconsistent with the common notions of the nature of matter. But those 



conditions were introduced merely to indicate joint tendencies, without 

 PltOC. AMEK. PIIII.os. soc. XVIII. 102. F. P1HKTED DEC. 12, 1878. 



