54 FRAGMENTS OF SCIENCE. 



ous degrees of darkness and incandescence, with the 

 following results: 



Appearance . Energy of 



of spiral obscure rays 



Dark . . . . .... . 1 



Dark 6 



Faint red . . . . . . . . 10 



Dull red . . . .... . 13 



Red . . . . * . . . . 18 



Full red . . 27 



Orange 60 



Yellow . . 93 



White ... ...'.'. .122 



Here, as in the former case, the dark and bright 

 radiations reached their maximum together; as the one 

 augmented, the other augmented, until at last the en- 

 ergy of the obscure rays of the particular refrangibility 

 here chosen, became 122 times what it was at first. To 

 reach a white heat the wire has to pass through all the 

 stages of invisible radiation, but in its most brilliant 

 condition it embraces, in an intensified form, the rays 

 of all those stages. 



And thus it is with all other kinds of matter, as far 

 as they have hitherto been examined. Coke, whether 

 brought to a white heat by the electric current, or by 

 the oxyhydrogen jet, pours out invisible rays with aug- 

 mented energy, as its light is increased. The same is 

 true of lime, bricks, and other substances. It is true 

 of all metals which are capable of being heated to in- 

 candescence. It also holds good for phosphorus burn- 

 ing in oxygen. Every gush of dazzling light has asso- 

 ciated with it a gush of invisible radiant heat, which 

 far transcends the light in energy. This condition of 

 things applies to all bodies capable of being raised to a 

 white heat, either in the solid or the molten condition. 

 It would doubtless also apply to the luminous fogs 



