52 o Dr. Herschel's Experiments on the solar, and 



Table V. 



Stoppage of prismatic Heat of the Refrangibility of the Red Rays, 



and of the Invisible Rays. 





] 



led rays. 







Invisible rays. 



Bluish-white glass stops 



- 



375 



- 



- 



71 



Flint glass 



- 



*43 



- 



- 



OOO 



Crown glass 



- 



2 94 



- 



- 



182 



Coach glass 



- 



200 



- 



- 



H3 



Iceland crystal 



- 



200 



- 



- 





Calculable talc 



- 



1 33 



- 



- 



250 



Dark-red glass 



- 



692 



- 



- 



OOO 



Orange - 



- 



500 



- 



- 



273 



Yellow - 



- 



4*7 



- 



- 



200 



Pale-green 



- 



588 



- 



- 



375 



Dark-green 



■- 



786 



- 



- 



500 



Bluish-green 



- 



462 



- 



- 



800 



Pale-blue 



- 



700 



- 



- 



75o 



Dark-blue 



- 



7 1 



- 



- 



167 



Indigo 



- 



367 



- 



- 



222 



Pale-indigo 



- 



3*3 



- 



- 



250 



Purple - 



- 



444 



- 



- 



273 



Violet - 



- 



400 



- 



- 



250 



Crown glass, one side rough 



389 



- 



- 



600 



Coach glass, ditto 



- 



500 



- 



- 



500 



Crown glass, both sides rough 



47 1 



- 



- 



600 



Coach glass, ditto 



- 



833 



- 



- 



7*4 



Calcined talc 



- 



737 



- 



- 



889 



As a necessary introduction to the decisive experiment I am 

 going to analyse, I must remark, that it has been shewn in a 

 former Paper, that the prism separates invisible heat from the co- 

 loured spectrum, by throwing that which is less refrangible than 

 light to one side. But it has also been proved, that heat of the 

 same variety in refrangibility as the different colours, is likewise 

 contained in every part of the coloured spectrum. The question 

 which we are discussing at present, may therefore at once be re- 



