THE ECLIPSE OF LAST DECEMBER. 
139. 
impure, simply because multitudinous images of the visible 
crescent would overlap each other. But so soon as the sun’s 
crescent had become an exceedingly fine sickle the solar dark 
lines came into view, and were even more strongly marked than 
by the usual method. It was when this sickle was on the point 
of disappearing that Professor Respighi hoped to see Young’s 
bright-line spectrum. He failed, as we have said, though the 
solar spectrum became continuous immediately before the 
totality (which, after all, demonstrates as effectually the exis- 
tence of the exterior absorptive atmosphere as though the 
bright lines had been seen). At the end of totality, just as the 
sun’s limb appeared, a stratum of bright lines was seen pro- 
jected upon the solar spectrum ; but Respighi 4 could not 
determine whether they were due to a general or partial reversal 
of the spectral solar lines, or to a simple discontinuity in the 
spectrum, since they were too soon immersed in a flood of light 
which put an end to the totality.’ 
4 At the very instant of totality,’ says Professor Respighi, 
6 the field of the telescope exhibited a most astonishing spectacle. 
The chrom(at)osphere at the edge which was the last to be 
eclipsed — surmounted for a space of about 50° by two groups 
of prominences, one on the right the other on the left, of the 
point of contact, was reproduced in the four spectral lines,* 
C, D 3 , F, and Gr, with extraordinary intensity of light and the 
most surprising contrast of the brightest colours, so that the 
four spectral images could be directly compared and their 
minutest differences easily made out. In consequence of the 
achromation of the object-glass, all these images were well 
defined, and projected in certain coloured zones, with the tints 
of the chromatic images of the corona. My attention was 
mainly directed to the comparison of the forms of the pro- 
minences on the four spectral lines, and I was able to determine 
that the fundamental form, the skeleton or trunk, and the 
principal branches, were faithfully reproduced or indicated in 
the images, their extent being, however, greatest in the red, 
and diminishing successively in the other colours down to the 
line Gr, on which the trunk only was reproduced. In none of 
the prominences thus compared was I able to distinguish, in the 
yellow image D 3 , parts or branches not contained in the red 
image C.’ 
It must be pointed out, however, that some of the pheno- 
mena here described were, in all probability, merely subjective, 
and that the reliance placed by Professor Respighi in the 
particular method of discrimination he employed, does not 
seem altogether justified. The Gr image, or indigo image, 
* That is, in the colours corresponding to these lines. 
