448 FRAGMENTS OF SCIENCE. 



16 ; with the blackened cube as source, the absorption 

 by chloroform is 22 per cent., while that by the iodide 

 of methyl is only 1 9. This inversion is not the result 

 of temperature merely ; for when a platinum wire, 

 heated to the temperature of boiling water, is em- 

 ployed as a source, the iodide continues to be the most 

 powerful absorber. All the experiments hitherto made 

 go to prove that from heated lampblack an emission 

 takes place which synchronises in an especial manner 

 with chloroform. For the cube at 100 C., coated 

 with lampblack, the absorption by chloroform is more 

 than three times that by bisulphide of carbon ; for the 

 radiation from the most luminous portion of a gas-flame 

 the absorption by chloroform is also considerably in 

 excess of that by bisulphide of carbon ; while, for the 

 flame of a Bunsen's burner, from which the incan- 

 descent carbon particles are removed by the free ad- 

 mixture of air, the absorption by bisulphide of carbon 

 is nearly twice that by chloroform. The removal of 

 the carbon particles more than doubles the relative 

 transparency of the chloroform. Testing, moreover, 

 the radiation from various parts of the same flame, 

 it was found that for the blue base of the flame the 

 bisulphide of carbon was most opaque, while for all 

 other parts of the flame the chloroform was most opaque. 

 For the radiation from a very small gas flame, consisting 

 of a blue base and a small white tip, the bisulphide 

 was also most opaque, and its opacity very decidedly 

 exceeded that of the chloroform when the source of 

 heat was the flame of bisulphide of carbon. Com- 

 paring the radiation from a Leslie's cube coated with 

 isinglass with that from a similar cube coated with 

 lampblack, at the common temperature of 100 C., it 

 was found that, out of eleven vapours, all but one ab- 

 sorbed the radiation from the isinglass most powerfully ; 

 the single exception was chloroform. 



