1889.] of the various Species of Heacenly Bodies. L7o 



(X = 568). The amount of lead in the comet was probably small, and 

 the first band at 546 was evidently masked by the bright carbon 

 fluting observed on the same date. The diminution in brightness of 

 the comet as it receded from perihelion would account for the band 

 not being seen after June 25th. 



Carbon Absorption. 



There are a few cases in which we probably have to deal with 

 comparatively feeble manganese absorption, together with the 

 absorption of cool carbon masking the radiation of hot carbon. Here 

 both the hot carbon flutings are affected, instead of one as in the 

 previous cases. With regard to the 564 fluting, we have the cool 

 carbon absorption fluting at 560*7, masking the third maximum of the 

 hot carbon fluting at 554, and the manganese fluting at 558 dimming 1 

 the first maximum. The result is a band with two maxima as shown 

 fig. 7, one of these being at 564 and the other at 554 (the 



in 



Hot carbon radiation. 

 Cool carbon absorption. 

 Manganese absorption. 

 Integrated result. 

 Coggia's Comet, 1874. 



Fig. 7. Map showing the result of the integration of hot carbon radiation and the 

 absorption of cool carbon and manganese, compared with Coggia's Comet, 1874. 



third maximum of the hot carbon flutings), the latter being the 

 brighter. 



With regard to the other hot carbon fluting at 517, we have the 

 cool carbon absorption masking the first maximum, and we get the 

 apparently paradoxical result of the second maximum of the fluting 

 being brighter than the first, as shown in fig. 7. 



It is probable, too, that at this stage the outer layers of the hob 

 carbon vapour would also begin to absorb ; this would show itself in 

 the brightest least refrangible maxima. Just as the masking of D by 

 the balancing of absorption and radiation gives us the green line of 

 sodium in the absence of D in some of the condensing swarms, we 



