on the terrestrial Rays that occasion Heat. 465 







66th Experiment. 



0' 





Candle. Coach glass. 



60 6of 



5 



It stops 458 



rays 



63 62 ... 3 : if = ,54> 2 

 of flame-heat. 



67^ Experiment. 



0' 



5 

 It stops 516 



rays 



Candle. Iceland crystal. 



62| 6o| . . . 3f : if = ,484 

 of flame-heat. 





- 



68^ Experiment. 



Candle. Calculable talc. 



5 61% 6bf .. .3: i£ = ,6$5 



This substance stops only 375 rays of flame-heat. 







69th Experiment. 



0' 





Candle. Very dark red glass. 



6o-| 6of 



5 63} 6lf . ..2|::i = ,364 



This glass stops 636 rays of flame-heat. 



70^6 Experiment. 



Candle. Bark red glass. 



o' 6of 6of 



5 Hi 6if...2f :if = ,474 



It stops 526 rays of flame-heat. 



