TOTAL ECLIPSE OF THE SUN, APRIL 16, 1893. 
5G9 
The diameters of the moon and sun were such that this camera gave images of 
•183 inch and ‘176 inch respectively. The length of the spectrum given by the 
combination was 2\5 inches from D 3 to K or l'G5 inches from V (H^) to K. 
The light from the sun was reflected on to the prisms from the mirror of a 12-inch 
Cooke siderostat, and to keep any extraneous light from entering the camera, a 
wooden tube was put in the place ordinarily occupied by the collimator; at the end 
of the tube was a shutter which could be closed and opened from the camera end 
with a cord, and by means of this the length of exposures was regulated. 
On the top of the wooden tube was placed a small telescope to serve as finder, it 
being directed to a portion of the mirror not utilized by the prismatic camera; the 
arrangement is shown in the accompanying figure. 
Fig. 5. 
1 
Prismatic camera used in Pirazil. 
A small hut to enclose the siderostat was erected, and, with the exception of one 
side and the front, which were made of canvas on wooden frames (so as to be easily 
moved), it was built of wood. The fall for the clock weights was made by erecting a 
sort of gallows behind the hut, over which the clock cord was directed by pulleys. 
About ten feet away to the North, the hut to hold the prismatic camera was built, 
this was also small, being only sufficiently large to hold the instrument, and 
constructed in the same way as the one described above, the observer taking his 
place outside. 
The siderostat was set down on a firm concrete base and adjusted for latitude by 
watching the image of a star or the sun with a theodolite set in a meridian line North 
MDCCCXCVI.-A. 4 D 
