TOTAL SOLAR ECLIPSE OF AUGUST 0, 1896. 
9 
The 6-inch Prismatic Camera. 
The 6-inch prismatic camera, intrusted to Mr. Fowler, was essentially the same 
instrument as that employed for the Eclipse of April 16th, 1893, in West Africa." 
Instead of the mounting of my 6-inch Cooke telescope, however, the equatorial head 
of a Dallmeyer photoheliograph was adapted for the occasion, this resting upon a 
wooden stand which was afterwards tilled up with concrete. The wooden tube of the 
instrument was square in section and was firmly attached to the declination axis by 
a strong iron plate. A consideration of the position angles of the points of contact 
indicated that dispersion in an east and wmst direction would better show the clii’omo- 
spheric arcs, and the prism was placed accordingly. 
In 1893, ten dark slides, each holding three dry plates, were provided. The 
experience then gained showed that narrower plates would meet all requirements, so 
five compartments were made to rejalace the three in each slide, and in this way 
fifty plates became available. 
Guided by the results obtained in 1893, the following table of exposures was drawn 
up for this instrument:— 
# 
Phil. Trans.,’ A, 1896, vol. 187, p. 559. 
VOL. OXC.—A. 
0 
