;6'2 



PHILOSOPHICAL TRANSACTIONS. 



[ANNO 1800. 



Exper. Q4. — I placed my apparatus at 5 feet from the 

 prism, and so as to cause the red-making rays to fall be 



Min. 



Red rays. Bluish-white glass. 



Therm. A. Them. B. 



tween the parallel lines in order to find what heat-mak- 75-f 754 



in°- rays would come to the thermometer along with them. 5 77-f- 764 . . . 2 : 14 = .625. 



"From this experiment it appears, that when 1000 red-making rays fall on each transmitting hole, 

 375 of them, if they also be the heat-making rays, are stopped by the bluish-white glass which covers 

 one of these holes ; or, what requires no other proof than the experiment itself, that 375 rays of heat, 

 of the same refrangibility with the red rays, are intercepted by this glass. 



Exper. 95. 



Eiper. 9$ 



Exper. 97. 



Exper. 98. 



Exper. 99 



Exper. 



Exper. 



Eiper. 



Exper. 



Exper. 



Exper. 



Exper. 



Min. 







5 

 Min. 







5 

 Min. 







5 

 Min. 







5 

 Min. 







5 

 Min. 



100. 

 5 



Min. 



101. 

 5 



Min. 



102. 

 5 



Min. 



103. 

 5 



Min. 



104. 

 5 



Min. 



105. 

 5 



Red rays. 

 75| 

 111 

 Red rays. 



7^ 

 78 



Red rays. 



541 



55-1 

 Red rays. 



7H 



78 

 Red rays. 



51| 



534 

 Red rays. 



m 



78i 

 Red rays. 



75 



77 

 Red rays 



75$ 



764 

 Red rays. 



74| 



76-f 

 Red rays. 



68| 



70\ 

 Red rays. 



69 



704 



Min. Red rays. 

 106. 694 



5 70| 



Min. Red rays. 



Exper. 



Exper. 107. 

 5 

 Min. 

 108. 

 5 

 Min. 

 Exper. 109. 

 5 

 Min. 

 Exper. 110. 

 5 

 Min. 

 Exper. ill. 

 5 



67 

 68| 



Red rays. 

 68 J 



rot 



Red rays. 



69 



71 

 Red rays. 



564 



58] 

 Red rays. 



574 



594 



Flint glass. 

 75± 

 tft,..ll 



Crown glass. 



75-1 



77i...2i: l£ = .706 

 Coach glass. 



53| 



54f . . . 14 

 Iceland crystal. 



75| 



77J... I*: 1| =-800 

 Calcinable talc. 



514 



52i . . . H : 

 Dark red glass. 



764 



77i • • • H : I = -308. 

 Orange glass. 



7H 



75f ...2: 

 Yellowglass. 

 75 



75f...l| 

 Pale green glass. 

 74i 



75... 2^:4 = .412. 

 Dark-green glass. 

 6si 



694 ... 1| : 4= .214. 

 Bluish- green glass. 



684 



69i...H: 

 Pale-blue glass. 



69| 



694. .-14 = 

 Dark-blue glass. 



674 



6*4... 1|:14= .929. 

 Indigo glass. 



6*4 



69}.. • 2: 14 = .633. 

 Pale indigo glass. 



6H 

 • 70 ... 2 : 14 = .687. 

 Purple glass. 



56 



574 •- • 24 

 Violet glass. 



57 



58i... 14 



This glass stops only 143 rays 

 of heat which are of the same 

 refrangibility with the red rays. 



This glass stops 294 rays of the same sort 

 of heat. 



1 = .800. It stops 200 rays of the same sort of heat. 



This 



substance stops 200 rays of the 

 same sort of heat. 



14 = .867. It stops 133 rays of the same sort of heat. 



This glass stops 692 rays 

 sort of heat. 



of the same 



1 = .500. It stops 500 rays of the same sort of heat. 



4 = .583. It stops 417 rays of the same sort of heat. 



It stops 588 rays of the same sort of heat 



It stops 786 rays of the same sort of heat. 



I = .538. It stops 46'2 rays of the same sort of heat. 



= .300. It stops 700 rays of the same sort of heat. 



This glass stops only 71 rays of the same 

 sort of heat. 



It stops 367 rays of the same sort of heat 



It stops 3 1 3 rays of the same sort of heat. 



1 4 = .556. It stops 444 rays of the same sort of heat. 



11 b .600. Itstops 400 rays of the sm sort of heat. 



