Chase.] -^^4: [jan. 7. 



verifications or rectifications by means of varying pressures. * In the follow- 

 ing year I introduced tlie liypotliesis, which has since been largely devel- 

 oped by Edlund, that electricity consists simply of sethereal vibrations. f 

 In confirmation of this hypothesis, I showed that many of the phenomena 

 of terrestrial magnetism can be produced by simple mechanical vibrations, 

 resembling those of the atmospheric currents whicli arise from the com- 

 bined action of terrestrial rotation and thermal convection.:]: In connec- 

 tion with these investigations I called attention to the importance, and 

 some of the probable consequences, of radial and tangential oscillations 

 moving with the rapidity of light,% and of their bearing upon "the phe- 

 nomena of light, heat, electricity, polarity, aggregation, diffusion, meteor- 

 ological changes, seismic tremors, crystallization, stratification, chemical 

 action and general morphology. "|| 



My discovery of numerous numerical relations between gravity and mag- 

 ' netism, for which the American Philosophical Society awarded its Magel- 

 lanic medal, led me to seek, in the maximum manifestations of gravitating 

 force, the cori'elation of gravity with other forms of energy, for which Fara- 

 day** had looked confidently but in vain. The greatest gravitating force in 

 our system and, therefore, the greatest of which we have any direct and 

 positive evidence, is at Sun's surface, where material particles are subjected 

 to such oscillations as may arise from the conflicting centripetal energies of 

 solar attraction and of the resultant attraction of all other cosmical bodies. 



In applying the fundamental equation, » = ^, at Sun's surface or the lo- 



cus of maximum gravitation, I found that the equality of action and reac- 

 tion, as shown by the sum of the solar-central gravitating reactions against 

 the sum of the gravitating actions towards the centre of the solar system, 

 in the cyclically alternating thrusts and pulls of half-rotation, is repre- 

 sented by the velocity of Ught.\\ This discovery, together with the iden- 

 tification of the same velocity as a factor of electro-magnetic action, which 

 was completed and confirmed by the investigations of Thomson and Max- 

 well, brought all physical phenomena, cosmical as well as molecular, within 

 the domain of Photodynamics. 



The molecular phenomena may be readily connected witli the cosmical, 

 through the correspondence between Challis's laws of molecular action and 

 the laws of attraction and rotation. :J:| They furnish grounds for estimating 

 Sun's mass and distance by means of the explosive energj^ of hydrogen ;gg 

 for discovering some of the subordinate elements of planetary arrange- 



*Ib. ix, 28S; x, 376. 



fib. ix, 355-60. 



if lb. ix, 367-71, 425-10, 487-M5; x, 97-1 is, 1.51-66. 



gib. ix, 40=-ll. 



1 lb. ix, 439. 



**Exp. Res., 2614. 



ttProc. Am. Phil. Soc, xi, 103-7. 



++Ib.ix,. 867-71. 



?g lb. xii, 392-4. 



