contraction of the solar mass ; f4) dis- 

 sociation of compound bodies in the 

 sun's substance. 



It will be observed that there is no 

 recognition here of the two f^rms of 

 light and heat; the sun is by all of them 

 made the manufacturing place of light 

 and heat, as well as the distributing re- 

 servoir, whence the whole solar system 

 is supplied ; not with the invisible, in- 

 sensible, potential, light and heat, to be 

 developed where required, but with these 

 actual forces. 



The first hypothesis, that of "com- 

 bustion," is virtually given up by scien- 

 tists on account of its insuperable diffi- 

 culties. The fuel problem is too in- 

 tricate for the finite mind. 



The second, the so-called mechanical 

 hypothesis, is held in greatest favor by 

 scientists to-day as best accounting for 

 the phenomena ; or as being least vul- 

 nerable to objections. This hypothesis 

 pre-supposes the presence in space of 

 an incalculable supply of ' ponderable 

 masses, all roving loosely and by chance, 

 until falling under the influence of the 

 sun they are drawn thereto with such 

 momentum that the concussion gives 

 rise to inconceivable light and heat. We 

 may, however, be allowed to question 

 whether the doctrine of chance can ac- 

 count for our exact and definite supply 

 of light and heat without excess or de- 

 ficiency. But such existence of ponder- 

 able matter, away from the influence of 

 gravity, moving about in the universe, 

 and assumed to follow the attraction of 

 the nearest stellar system, can hardly be 

 credited by philosophic minds. 



It is incredible that such matter has 

 ever by any agencies escaped from the 



