518 Prof. TyndalPs Contributions to Molecular Physics. 



Chloroform . . . 

 Chloroform 

 Bisulphide of carbon 

 Bisulphide of carbon 

 Total heat . . . 



Deflection. 



16-5 

 16-0 

 190 

 19*4 

 68-4 



And again, with an intermediate total heat,- 



Chloroform . . . 

 Chloroform . . . 

 Bisulphide of carbon 

 Bisulphide of carbon 

 Total heat . . . 



Deflection. 



10-2 

 10-0 

 12-0 

 11-8 

 60-0 



Absorption. 



8-4 

 8-2 

 97 

 9-9 

 100-0 



Absorption. 



8-4 

 8-4 

 9-8 

 97 

 100-0 



There is therefore no doubt that, while in the case of a platinum 

 spiral at all temperatures, of a luminous gas-flame, and, more 

 especially, in the case of lampblack heated to 212° Fahr. the 

 absorption of chloroform exceeds that of bisulphide of carbon, 

 for the flame of Bunsen's burner the bisulphide is the more 

 powerful absorber of the two. The absorptive energy of the 

 chloroform, as shown in Table XX., is more than three times 

 that of the bisulphide, while in Table XXV. the action of the 

 bisulphide is nearly twice that of the chloroform. We have here, 

 moreover, another instance of the reversal of formic and sulphuric 

 ether. For the luminous jet the sulphuric ether is decidedly the 

 more opake; for the flame of Bunsen's burner it is excelled'in 

 opacity by the formic. 



§ X. Radiation from the flames of hydrogen and carbonic oxide 

 through air and ot^er media. — Influence of period with refer- 

 ence to absorption. 



The main radiating bodies in the flame of a Bunsen's burner 

 are, no doubt, aqueous vapour and carbonic acid. Highly 

 heated nitrogen is also present, which may produce a sensible 

 effect : the unburnt gas, moreover, in proximity with the flame, 

 and warmed by it, may contribute to the radiation, even before 

 it unites with the atmospheric oxygen. But the main source of 

 the radiation is, no doubt, the aqueous vapour and the carbonic 

 acid. I wished to separate these two constituents, and to study 

 them separately. The radiation of aqueous vapour could be ob- 

 tained from a flame of pure hydrogen, while that of carbonic acid 

 could be obtained from an ignited jet of carbonic oxide. To me 

 the radiation from the hydrogen -flame possessed a peculiar inter- 

 est ; for, notwithstanding the high temperature of such a flame, 



