L96 
SIR NORMAN LOCK^ER AND OTHERS ON THE 
exposure. These bands gradually disappeared as totality approached, and the 
spectrum of the chromosphere, which before showed its bright lines as short arcs at 
the cusps, then exhibits them as complete arcs broken up by the lunar irregularities. 
Later, the spectrum of the upper chromosphere appears alone, the lines being then 
relatively few in number (bottom of Plate 6). 
As the middle of totality approaches, the chromospheric arcs lose their importance, 
and the ^Ji’incipal features of the spectra then are the continuous spectrum of the 
corona and the coronal rings; at this time relatively long exposures are required to 
secure adequate photographic records. The continuous sj^ectrum is not of uniform 
intensity on account of the unequal distribution of coronal lio'ht round the limb 
(Plate 7). 
As the end of totality aj^proaches, the chromospheric arcs reappear, now in the 
part corresponding to the sun’s south-western limb, and the phenomena shown on 
Plate 6 are repeated in inverse order. It has not been thought necessary to reproduce 
the ten photographs taken at these stages. 
The prominences visible throughout the eclipse were neither large nor numerous, 
and their spectra show comparatively few lines. One, in the south-east quadrant, 
appears in all the photographs. 
The principles governing the interpretation of photogiaphs taken by the prismatic 
camera, both in and out of totality, are fully described in my report of the photo¬ 
graphs obtained in 1893.* 
Photographs taken with the ^-inch Prismatic Camera. 
The programme adopted was similar to that of the 6-inch, there being two large 
plates (16 X 6|^) for recording a series of ten snapshots at and near the times of 
second and third contacts, and nine smaller plates for exposure during totality. All 
the exposures were successfully made, but the lines in the spectrum are not very 
sharp, owing to warping of the wooden tube by the heat and the consequent disturb¬ 
ance of the focus. 
As has been previously stated, this instrument was so mounted that the arcs should 
appear symmetrical about the direction of dispersion. It is satisfactory to state that 
the photographs showed that the experiment was very successful, the arcs coming out 
exactly as calculated. Although this instrument was capable of only giving about 
half the dispersion of the 6-inch, the ojjtical parts were better adapted for recording 
the ultra-violet region of the spectrum. 
Particulars as to the photographs taken are given in the following table :— 
* ‘ Phil. Trans.,’ A, vol. 187 (1896), pp. 551-618. 
