G. W. Hough on Cataloguing and Charting Stars. 178 
we readily make the necessary correction. The use of this ap- 
paratus in no wise interferes with our work for exact positions, 
since we have found the mean error of our observations to be 
the same-whether the stars were charted or not. 
Our work for the past year has demonstrated the practical 
utility of this apparatus. If for any purpose we desire a ma 
of the stars in a certain position of the heavens, we can mak 
one in a few minutes, which by any other method would require 
hours. In the region of the ‘milky-way, where small stars are 
very numerous, we have charted them at the rate of 480 per 
hour, and at the same time observed every star above the 14th 
magnitude. 
is easily accomplished by merely pricking through the paper, 
With a series of points which shall at once indicate the magni- 
udes, 
‘Suitable to the instrument. These minor details, of course, will 
0 arranged by the observer, as circumstances require. 
; Dudley Observatory, March 16th, 1864. 
