170 Mr. J. N. Lockyer. On the Classification [Jan. 10, 



masking effect of the bright carbon fluting beginning at 564. The 

 radiation of manganese, and sometimes of lead, is added to that. of 

 carbon, since the first fluting (558) of manganese falls in the carbon 

 band ; the result is a new band of a different form. A further com- 

 plication, as we shall see, is added when lead, as well as manganese, 

 makes its appearance. 



The addition of the manganese radiation does not take place in all 

 comets at an equal number of days from the perihelion passage ; it 

 depends upon the perihelion distance, so that the irregularities in 

 question are not observed in all comets. 



Manganese Radiation. 



When we deal with the integration of the bright manganese 

 fluting at 558, which fades away towards the red, and the carbon 

 fluting at 564, fading towards the blue, we have as a result a band 

 brightest in the centre and fading off in both directions. If both 

 flutings are well developed there will be a single broad maximum 

 extending from 558 to 564, as shown in fig. 3. If both were rather 



Hot carbon radiation. 

 Manganese radiation. 



Integrated result. 



Great Comet 1882 (Cope- 

 land). 



3. Diagram showing the result of the integration of not carbon (517) and 

 manganese (558) radiation, compared with the Great Comet of 1882. 



feeble there would be two maxima, one at 558 and one at 564; but 

 this condition has not yet been recorded. 



In the Great Comet of 1882, when at a considerable distance from 

 the sun, on October 22nd, the perihelion passage occurring on Sep- 

 tember 17th, the broad maximum condition, as shown in fig. 3, was 

 recorded by Copeland. 



