on the terrestrial Rays that occasion Heat. 461 



Crown glass; the rough side to the sun. 



Sun. 



Coach glass ; ditto. 



Crown glass ; rough on both sides. 



Coach glass ; ditto. 



o' 57i 57i 



5 6 2 i 58£...5*: J = ,146' 



These four glasses stop no more than 854 scattered rays of 

 heat, and 995 of light. 



Sjtb Experiment. 



I used now a piece of glass of an olive colour, burnt into the 

 glass, in the manner that glasses are prepared for church 

 windows, which transmits only scattered light. 



Sun. Olive-coloured glass. 



o' 69 69 



5 1H 7°£ • • • 7i : 1* = .iff* 



This glass stops 839 scattered rays of heat, and 984 of light, 



$8tb Experiment. 



Sun. Calcined tale. 



5 551 5*i • • • m : I = »*33 



This substance stops 867 scattered rays of heat, and so much 



light that the sun cannot be perceived through it.* 



59th Experiment. 



Sun. White paper 



o' 63 63 



5 68 6si . . . 5 •• 4 = ^5° 



This substance stops 850 scattered rays of heat, and 994 of 

 light. 



• See the 175th Experiment. 

 MDCCC. 3 O 



