120 
CAPTAIN W. DE W. ABNEY ON THE TOTAL ECLIPSE 
though sufficiently exposed, showed that n. large image could he utilised. They were not, 
however, satisfactory, owing to a multiplicity of images being formed, due to the shake 
given to the instrument by the insertion of the slides in the smaller instrument, the 
large pictures requiring considerably more exposure than these latter. In the matter 
of spectroscopic analysis of the eclipse phenomena, Mr. Lockyer devised an ingenious 
contrivance for securing impressions of the bright lines seen immediately after and 
before totality. These photographs were only partially successful, and will not be 
considered in this report. The number of instruments to be used by the two observers 
and the assistants they hoped to obtain were nine, entailing the use of 11 cameras. 
Only two equatorial mountings accompanied the expedition, and it was impossible to 
mount all these instruments on them, had it been advisable, indeed, to do so. A. 
siderostat, having a 12-inch silver-on-glass mirror, was therefore taken, four of the 
instruments being stationary, reflected light being utilised. 
The following was the disposition of the instruments :— 
On the 1st equatorial— 
A. A finder of 3|-inch aperture was attached to the above for viewing the 
eclipse. 
B. A 7-prism spectroscope, with camera attached, for obtaining photograjDhs near 
the sun’s limb immediately before and after totality. 
C. A 6-inch achromatic telescope by Cooke, of York, the eye-piece being with¬ 
drawn. Attached to it was a Eutherfurd grating of 17,200 lipes to the 
inch, to be used for obtaining spectra of the corona in the 1st and 2nd order, 
two cameras being employed. 
D. A slit spectroscope, having one prism of dense flint glass. The condenser 
throwing the image of the moon on the slit was a photographic lens by 
Dallmeyer, of 6-inch focus. 
On the 2nd equatorial were mounted— 
M. The photoheliograph for taking 4-inch pictures. 
N. The corona camera, having a lens of 4-inch aperture, and 5 ft. 6 in. focal length. 
The instruments used with the siderostat were— 
F. A photographic spectroscope to be used without a condenser, consisting of one 
prism of white flint, a collimator 4l feet long, and a lens attached to the 
camera of 3-inch aperture, and of about 9-inch focus. In this case the photo¬ 
graphic ]3late was caused to move vertically during exposure of the plate by 
means of clock-work for the registration of bright lines immediately before 
and after totality. 
G, A slit spectroscope of two prisms of the same dimensions as that used in 
Egypt in the eclipse of 1882, and described in Dr. Schuster’s and my report 
