220 RESULTS OF OBSERVATIONS OF COMETS FABRY, BARNARD, 
observed across a single position thread of the micrometer, while 
differences of declination were obtained by means of the distance 
of York, the makers of the telescope itself. It is similar in its 
construction to that designed by Mr. Graham, and employed by 
stretched across the opposite angles of the square. These were so 
placed by the makers at my suggestion. One of these threads, 
invariably adopted as the declination thread, serves as a rea 
means for orienting the micrometer. The adjustment is effected 
equator shall travel accurately along the thread during its a 
ae or the field of view. This adjustment is “made at 
titude, so that the star’s path may not be sensibly affected 
by Reso and it is always verified at the time of the comet 
observations. It was found, however, that, o owing to errors in the 
form of the square, the differential right ascensions of objects were 
all the differential right ascensions, but no sensible error arises 
in the results for differential declination. I may add, from my 
own experience, that when a square bar-micrometer is treated in 
the way I have described, its results are superior to those derived 
from the ordinary ring. The differential measures of the comet 
are corrected where necessary for proper motion, and also for 
refraction, when it is likely to be sensible. The resulting places 
of the comet, uncorrected for parallax, are exhibited in one of the 
accompanying tables. 
Comet Barnarp. 
Two days after the discovery of Fabry’s comet Mr. Barnard, of 
Nashville, U.S., detected another faint comet near the Equator. 
After a few positions were obtained, it was found that this comet 
would also approach the earth so as to become visible, without a 
nounced Fabry’s comet to the Australian Observatories also 
brought news of this second discovery. Ample time was, there- 
fore, ‘afforded for the preparations for observation. On May 30th 
e comet came sufficiently south to be picked up in the bright 
