394 



Transactions. — Astronomy. 



Art. LX. — The Maintenance of the Sun's Heat. By Professor 

 F. D. Brown. (Abstract of a Lecture.) 



[Read, before the Auckland Institute, 29fft July, 1885.1 



The maintenance of the sun's heat : of what possible interest 

 is this ? perhaps you will say. Nevertheless, it is recorded that, 

 centuries ago, a man was tending a flock of sheep, when he saw 

 " a flame in the midst of a bush, and the bush burned with fire 

 and was not consumed." And this man, although he lived at a 

 time and in a country where no spirit of inquiry existed, yet 

 thougbt that this was a matter of the greatest interest, for he 

 said, " I will now turn aside, and see this great sight, why the 

 bush is not burnt." Why, then, should we not turn aside for a 

 few minutes, and ask ourselves, How is it that that great blazing 

 mass, which daily lights and warms us, burns, and is not con- 

 sumed ? But it may be said that there is here a pure assumption 

 introduced, to lend a fictitious interest to the subject; that there 

 is nothing more remarkable in the existence of a vast mass of 

 matter at a white heat than at any other temperature, and that 

 the extraordinary statement that the sun is not consumed has 

 no basis in fact, or, at any rate, cannot be proved. 



The first point, therefore, for us to consider is, whether the 

 sun does behave in a manner altogether different from ordinary 

 fire, or a white-hot ball ; whether he keeps on shining longer and 

 more fiercely than a fire of his size could do. The solution of 

 this question is by no means difficult, though it involves the use 



