254 Prof. Tyndall on Recent Researches on Radiant Heat. 



I. Gases. 

 Name of gas. Deflection. 



Atmospheric air 6°. 



Oxygen 8°; 8°; 7°; 7°. 



Nitrogen, 20th July .... 6°; 5°. 



Again, 25th July 7°; 7°. 



Hydrogen 10°; 10°. 



Carbonic oxide 34°; 34°; 34°. 



Carbonic acid 37°-5; 35°; 37°*5 ; 37°. 



Nitrous oxide 57°-5 ; 57°-5 ; 57°'5 



Olefiant gas, 1 inch tension . . 43° ; 43°. 



„ 5 inches .... 62°«5 ; 62°'5. 



„ 30 inches .... 74°. 



Coal-gas, 1 inch tension . . 28°. 



5 inches .... 54°; 53°. 



30 inches . ... 74°; 74°. 



Total heat 79°'8. 



The figures separated from each other by semicolons indicate 

 the results of different experiments ; and their close agreement 

 shows the accuracy which, even in this early stage of the inquiry, 

 the experiments had attained. The above deflections represent 

 the following absorptions, at a common tension of 30 inches of 

 mercury. 



II. 

 Name of gas. Absorption. 



Atmospheric air 6 



Nitrogen 6 



Oxygen 7 



Hydrogen 10 



Carbonic oxide 34 



Carbonic acid 37 



Nitrous oxide 110 



Olefiant gas 345 



Coal-gas 345 



The vapours of the following substances were also examined 

 in the same month, at a common tension, and the annexed 

 results were obtained. 



III. Vapours. 



Name of vapour. Deflection. 



Bisulphide of carbon 16°; 17°. 



Bichloride of carbon 33°; 33°. 



Iodide of methyle 37°*5; 37°5. 



Chloroform 40°; 41°; 40°. 



Benzole 43°; 43°; 44°. 



Amylene 55°; 55°. 



