MR. J. NORMAN LOCRTER ON THE 
5 50 
limb. The yellow ring was much fainter on the whole, but more uniform all round 
the sun. 
In 1883 the same instrument used in Egypt in 1832 was employed, as well as 
a G-inch achromatic telescope, and a concave Rowland grating of 5 feet focus, 
arranged for taking ring spectra in the first and second orders. 
It is stated in the report* that the photographs “possess no features of interest,” 
and neither reproductions, nor drawing, nor measurements are given. 
The prismatic camera employed in the eclipses of 1882 and 1883 was again used 
in the West Indies in 1886. Only the spectra of some prominences seem to have 
been recorded. There is no mention of rings. The hydrogen lines as well as 
K and f are noted.! 
While on the one hand the photographic results, to which reference has been 
made, certainly did not come up to the expectations raised by my observations 
of 1871, on the other, subsequent solar investigations confirmed my opinion that this 
was the best way of studying the lower parts of the sun’s atmosphere, provided an 
instrument of much greater light-grasping power could be employed. 
I determined, therefore, when arranging for the observations to be made during 
the eclipse of 1893, to renew the attack with the largest telescope and the greatest 
dispersion at my command. 
The Solar Physics Committee is now in possession of a prismatic camera of 
6 inches aperture. I decided, therefore, to employ it, all the more because the work 
on stellar spectra at Kensington had given abundant proof of its excellence. 
The object glass of this instrument, corrected for the photographic rays, was 
constructed by the Brothers Henry. The correction is such that it is unnecessary 
to incline the back of the camera, and hence some of the objections which have been 
made to the use of this form of spectroscope are overcome. The large refracting 
angle of the prism (45°) obviously increases the value of the instrument for eclipse 
work. This instrument was placed at the disposal of the Eclipse Committee, by the 
Solar Physics Committee, and w T as entrusted to Mr. Fowler, who took the photo¬ 
graphs at the African station. 
Although no other instrument of this power was available, it seemed important 
that a series of similar photographs should be attempted at another point on the line 
of totality. A spectroscope belonging to the Astrophysical Laboratory of the 
Royal College of Science was lent for the purpose by the Department of Science and 
Art, and a siderostat used in conjunction with it was lent b}^ the Royal Society. 
These instruments formed part of the equipment of the Brazilian expedition, and 
were placed in charge of Mr. Shackleton, Computer to the Solar Physics Committee. 
The following sections give, first, reports of the operations at the two stations 
contributed by Messrs. Fowler and Shackleton, in charge of the instruments at 
* 1 Phil. Trans.,’ 1889 A, vol. 180, p. 122. 
f 1 Phil. Trans.,’ 1889 A, vol. 180, p. 319. 
