554 
MR. J. NORMAN LOCKTER ON THE 
Respighi’s observations were made with a telescope of 4^ inches aperture with a 
large prism of small angle in front of the object glass. A negative eyepiece magni¬ 
fying 40 times and having a field view large enough to include the whole of the 
spectrum was employed. The principal results obtained by Respighi were as 
follows”':— 
“ At the very instant of totality, the field of the telescope exhibited a most 
astonishing spectacle. The chromosphere at the edge which was the last to be 
eclipsed.was reproduced in the four spectral lines C, D 3 , F, and G, with 
extraordinary intensity of light. 
“Meanwhile the coloured zones of the corona became continually more strongly 
marked, one in the red corresponding with the line C, another in the green, probably 
coinciding with the line 1474 of Kirchhoff’s scale, and a third in the blue perhaps 
coinciding with F.” 
“ The green zone surrounding the disc of the moon was the brightest, the most 
uniform and the best defined.” 
My observation! was made intermediately between the two observations of Professor 
Respighi. The observations may be thus compared 
Respighi 0 D 3 F.G-. Chromosphere and prominences at beginning of 
totality. 
Lockyer C 1474 (faint) E.G. Corona 80 secs, after beginning of totality. 
Respighi C 1474 (strong) F. Later. 
I had no object glass to collect light, but I had more prisms to disperse it, so that 
with me the rings were not so high as those observed by Respighi, because I had 
not so much light to work with; but such as they were, I saw them better, because 
the continuous spectrum was more dispersed, and the rings (the images of the corona) 
therefore did not overlap. Hence, doubtless Respighi missed the violet ring which 
I saw ; but both that and 1474 w T ere very dim, while C shone out with marvellous 
brilliancy, and D 3 was absent. 
In arranging for the eclipse of 1875 in Siam and the Nicobars, the method was 
further developed by the introduction of photography, and the first results of this 
extension were given in the report of the Eclipse Expedition of that year. They 
showed clearly that with the rapid dry plates of to-day a considerable increase of 
dispersion might be attempted. 
The object glass employed on this occasion had an aperture of 3§ inches and a focal 
length of 5 feet, while the prism had a refracting angle of 8 degrees. 
Two photographs were obtained with exposures of one and two minutes 
respectively. Both are reproduced in the Report,]; and they show only such 
* ‘ Nature,’ vol. 5, p. 237, 1872. 
f ‘Brit. Assoc. Report,’ 1872, p. 331. 
1 < Phil. Trans.,’ 1878, vol. 169, Part 1, p. 139. 
