APPENDIX II. 123 



CO2 heated to different stages from 300° to 1460°, which is the tem- 

 perature ( ?) of the Bunsen flame. The latter has its maximum at 

 4.40 /I. It will be noticed in the curves that, for the amyl-acetate flame, 

 the CO2 maximum is situated at 4.36 fi, while for the Bunsen acetylene 

 and the Bunsen gas flame the maximum is sharp at 4.40 fx. This would 

 appear to indicate a lower temperature than 1460°. Plotting the values 

 of temperatures and wave-lengths, found by Paschen, it was found that 

 for the amyl-acetate lamp the maximum at 4.36 /i indicates a tempera- 

 ture of 1370° C. 



This discrepancy is no doubt due to the use of the large spectrometer, 

 which magnifies the atmospheric absorption band at 1.37 /t (Langley's 

 il/=i.4fi), and consequently lowers the emission curve of the amyl- 

 acetate lamp, which happens to come just at this point. However, this 

 still leaves a difference of 200° unaccounted for, which emphasizes the 

 lack of our knowledge of the term " temperature " as applied to such a 

 radiator. 



