478 Dr. Herschei/s Experiments on the solar, and 



the upper part of the transmitting glasses, to keep them in their 

 situation. 



Fire. Bluish-white glass. 



o' 66 66 



5 86 71 . . . 20 : 5 = ,250 



This glass stops 750 rays of lire-heat. By looking through it, 

 at the same place in the fire, after the screen was removed, in 

 order to cool the apparatus for the next experiment, I found that 

 this glass can hardly be said to stop any of the light of the fire. 



118th Experiment. 



Fire. Flint glass. 



o' - 67 67 



5 87 72 ... 20 : 5 = ,250 



It stops 750 rays of fire-heat. 









ngth Experiment. 









Fire. 



Crown glass, 





o' 





6 7 



67 





5 





86f 



72i. 



It 



stops 722 



rays 



of fire-heat. 





i9i:5i = .*78 



lQOth Experiment. 



Fire. Coach glass. 



o' 6 7 |- 6 7 i 



5 8<% 73.-.i9£:5i = >28S 



It stops 714 rays of fire-heat. 



121st Experiment. 



Fire. Iceland crystal. 



o' 68 68 



5 9°t 73* •• .22^:51 = , 244 



This substance stops 756 rays of fire-heat. 



