556 Chronicles of Science. [ Oct., 
end is the brightest, and it diminishes almost uniformly both in 
brightness and in breadth from that end uniformly to the other. 
The least refrangible band lies between D and E, and is faintest 
towards its extremities. The bands could not be resolved into 
lines. All of them were brightest in the middle of their breadth— 
an appearance due, of course, to the superior brilliancy of the comet’s 
nucleus. But the apparent diminution of the breadth of the two 
more refrangible bands must not be ascribed to any difference in 
the spectra of the coma and nucleus, since it is clearly due to the 
diminution of the comet’s light from the centre towards the cir- 
cumference. The effect of this diminution would be to render the 
edges of the fainter parts of the spectrum invisible. ‘The marginal 
portions of the coma were found to give the same spectrum; but 
when the light became very feeble Mr. Huggins imagined that 
he could trace a continuous spectrum underlying, so to speak, the 
discontinuous one. ‘The tail was too faint to exhibit any spectrum. 
But the most remarkable part of Mr. Huggins’ researches 
remains to be mentioned. He found that the spectrum of the 
comet presented so close a resemblance to diagrams he had formed 
in 1864 of the spectrum of carbon, that he was induced to make a 
more exact comparison. Dr. Miller was present while the requisite 
observations were being made, and took part in them. Our space 
will not permit us to enter as we could wish into a full account of 
the arrangements made use of by Mr. Huggins. It must suffice 
for us to state that the spectrum of carbon, as seen (in combination 
with the hydrogen spectrum) when the spark from an induction 
coil is taken through olefiant gas, was brought into direct com- 
parison with the spectrum of the comet. Mr. Huggins and 
Dr. Miller were both satisfied that within the limits of the m- 
strument’s power of indication the two spectra were coincident, 
not only in the position of their bands, but also in their general 
character and their relative brightness. The observations subse- 
quently made by Mr. Huggins confirmed this impression. The 
lines due to hydrogen were not seen in the spectrum of the comet. 
Mr. Huggins speculates with his usual acumen and caution on 
the remarkable discovery above recorded. ‘The great difficulty is 
to understand how a substance so fixed as carbon should be volatized 
when at considerable distance from the sun. In the case of a comet 
which approaches the sun very nearly, one can understand that 
effects should be produced differing wholly in character from any- 
thing we are familiar with on earth; but at the time of observation 
Winnecke’s comet was not near to the sun. However, as Mr. 
Huggins remarks, we can only regard the difficulty as one of 
degree. We are presented, in the case of the gaseous nebule, with 
instances of gas maintained permanently in a luminous state,—a 
phenomenon wholly inexplicable by any of the relations which 
