458 Dr. Herschel's Experiments on the solar y and 



4$tb Experiment. 



Sun. Gin. 



o' 52 52 



5 57a 53t- • -5i- *1 = ,261 



This compound stops ygg rays of heat, and 626 of light. 



/^gtb Experiment. 



Sun. Brandy. 



o' 56 56 



5 6o± 5 6^ . . . 44 == ,206 



This stops 794 rays of heat, and gg6 rays of light. 

 Other liquids have also been tried ; but the experiments hav- 

 ing been attended with circumstances that demand a further 

 investigation, they cannot now be given. 



Transmission of solar Heat through scattering Substances. 



50th Experiment. 

 I rubbed one of the pieces of crown glass, mentioned in the 

 26th experiment, on fine emery laid on a plain brass tool, to 

 make the surface of it rough, which, it is well known, will 

 occasion the transmitted light to be scattered in all directions. 

 Supposing that it would have the same effect on heat, I tried 

 the transmitting capacity of the glass, by exposing it with the 

 rough side towards the sun, over one of the transmitting holes 

 of the apparatus. 



Sun, Crown glass ; one side rubbed on emery. 



o' 67 67 



5 74 7°f • • • 7 : Si = >53 6 



The glass so prepared stops 464 scattered rays of heat, and 854 



of light. Now, as the same glass, in its polished state, trans- 



