408 
SIR XOEMAN LOCKYER AXD OTHERS 
(6.) From 20 to 52 seconds after beginning of totality. In this 23hotogTaph the 
decided chromospheric arcs seen in No. 5 are replaced by fragmentary rings repre¬ 
senting prominences and crests of the serrated parts of the chromosphere. H and K 
appear almost as complete rings, a little stronger on the eastern side. Several 
coronal rings, to which reference will be separately made later, are seen. The 
general continuous siDectrum overlapping the chromospheric and coronal rings, on 
account of the long exposure, is rather strong in this j^hotograph. 
(7.) From 58 to 69 seconds after beginning of totality. The brighter chromo¬ 
spheric arcs now appear on the western side of the sun, together with the images of 
certain prominences, and parts of coronal rings, the whole being involved in con¬ 
tinuous spectrum of moderate intensity. 
(8.) “ Instantaneous ” exposure G seconds before end of totality. Only a few of 
the brighter chromospheric arcs, on the western side of the sun, and a few promi¬ 
nences are seen in this photograph. Plate under-exposed. 
(9.) “Instantaneous” exposure, 4 seconds before end of totality. Very similar to 
No. 8, but more chromospheric arcs are visible. 
(10.) “Instantaneous” exposure probably about 2 seconds before end of totality. 
The photograph is very similar to No. 2, but the arcs are on the opposite (western) 
side. 
The spectra taken with the 20-foot prismatic camera are lOf inches long from Ha 
(vdiich appears on some of the photographs) to the strong titanium line at 3685‘34, 
and nearly 7T inches from Dg to K.' Those taken with the 6-inch 2-prism instru¬ 
ment have corresponding dimensions of about 8| inches and 5| ijiches respectivehn 
Photographs No. 2 (A), taken with the 20-foot prismatic camera, and Nos. 5, 6, and 
7 (B, C and D), taken with the 2 j^risin instrument, are reproduced in Plate 6. 
The photographs taken with the small objective gratings are very good, but show 
no features which are not seen in the larger photographs. They are chiefly of 
interest as showing 'udiat can be doiie with small and inexpensive instruments. 
Part V.— Discussiox of Besults. 
Bij Sir Noeman Lockyer, K.C.B., F.B.S. 
The Spectrum of the Chromospliere. 
Tlie spectrum of the chromosphere, as shown on the series of photographs taken 
with the prismatic cameras, greatly I'esembles that photographed in India in 1898.^' 
It is, therefore, not considered necessary to discuss at present the wave-lengths, 
intensities, and oiigins of the chromos 2 )heric arcs. 
* ‘riiil. Trans.,’ A, vol. 197, p. 151 
