On the Temperature of Incandescence. 22? 



low incandescence, such as usually forms upon a slag when its 

 surface is exposed by the removal of its crust, spreading to the 

 sides of the spot and leaving in the centre a clear space ; and 

 nothing in the admission of such a film is perhaps irreconcilable 

 with ordinary penumbral phenomena. 



Undoubtedly this hypothesis should be carefully considered 

 and submitted to the test of elaborate experimental examination, 

 before it could claim acknowledgment as a theory ; but although 

 the low specific gravity of the sun still opposes its acceptance, 

 unless perhaps it may be a mean of the specific gravities of the 

 liquid sphere and its gaseous surrounding atmosphere, I con- 

 cluded with some diffidence to advance it as naturally suggested 

 by the experiments herein described. 



Should it survive the scrutiny of critical consideration, it will 

 afford us the satisfaction of at least partly solving an important 

 problem, and furnish a striking illustration of the connection of 

 small things with great, in the transition of reasoning from 

 the phenomena of a blow-pipe bead to the phenomena of the 

 sun. 



