INTRODUCTION. 19 



water was allowed to come in contact 

 with its surface, to wit, the union and 

 decomposition of the elements of water. 

 Owing to the immensity of the sun's 

 mass, it will readily be perceived, that 

 a very much longer time would be re- 

 quired to reduce the temperature of the 

 surface sufficiently to allow water to 

 approach it, without being decomposed. 

 Whether this process of cooling is now 

 going on at the surface of the sun, by 

 which the solar system would be event- 

 ually deprived of the light and heat 

 imparted by that luminary, or whether 

 the decomposition and recomposition 

 of water is kept in exact equilibrium 

 by the caloric emitted, by which its 

 heat would be kept up for ever, are 

 questions very difficult of solution, at 

 present. 



