C. A. Young—The Solar Eclipse. 281 
(3.) A single-prism integrating spectroscope mounted equa- 
torially, with an opera glass in front of the slit as a condenser. 
The collimator and telescope had each an aperture of two and 
a half inches, and a focal length of twenty-six anda half. The 
prism, kindly loaned for the occasion by Professor Emerson of 
Dartmouth College, had a refracting angle of forty-five degrees, 
and faces two and a quarter by two and a half inches. It was 
mounted, not at the angle of minimum deviation, but in such 
a way that by moving a lever it could be slightly rotated so as 
to throw the spectrum across the field of view. e whole 
was mounted equatorially, but without clockwork, and was 
committed to Mr. C. D. Bennett. (4.) An integrating spectro 
scope of high dispersion by Grubb. This had telescope and 
collimator of one inch aperture and twelve inches focus, with a 
train of dense sixty-degree prisms, varying in number at 
pleasure from ten to four—six were used during totality—it 
was fitted with an opera-glass condenser like the preceding. 
he dispersive power was too great, and nothing at all was 
seen with it by Mr. H. S. Smith who had it in charge. 
: red at pleasure. The three inch telescope before men- 
tioned was attached to the same stand and arranged for polari- 
zation observations during the totality, but Professor Rockw 
did not get time to use it During the totality, Professor 
Brackett also examined the coronal images as seen by looking 
With the naked eye through a direct-vision prism of considera- 
ble dispersion, 
