2 CATALOGUE OF THE MAGNITUDES OF SOUTHERN STARS. 
the present Catalogue may be regarded as an Independent revision of Dr. Gould's 
work, within the described limits. With the exception of the stars a Cams Majoris, 
a Scorpii, and 102-3 (U. A.) Ormiis, which were considered too difficult to obtain 
trustworthy observations of, it is beheved that every star has been observed within 
the limits named, to the magnitude 7.0 inclusive. Many stars, generally fainter 
companions, whose positions are given in the U. A. Catalogue, but not there 
numbered, have also been included in the general work, although no attempt has 
been made to include all such cases, as these will receive attention in a later 
work. The observations were almost wholly discontinued during the years 1S83 
and 1885, owing to injury to the eyes from the trying nature of the work. 
Method of Observation. 
The first step was to enter upon the charts of the Uranometria Aj'gcntina the 
numbers of the U. A. Catalogue. The stars were then observed in sequences, by 
Argelander's method of step-estimations ; each sequence comprising adjacent stars 
within a moderate range of magnitude. Each sequence comprised about ten stars ; 
sometimes, in case of isolated groups, only five or six ; and occasionally, where 
there were many stars In the vicinity, more than twenty. The brightest star in 
the region was first selected, then the next brighter, and so on down, other stars 
being afterwards inserted in their appropriate places. 
The various differences of brightness were estimated in steps. When all stars 
in the neighborhood which could be conveniently observed had been included, a 
new sequence was begun, and so on. In those parts of the sequence near the limit 
of 7*^.0, after all the U. A. stars had been included, any stars in the sky which 
were as bright as the fiiinter stars of the sequence were Inserted in their proper 
places. During the first year's observations, in which nearly half of the whole 
work was done, an opera-glass was exclusively used. Afterwards a field l^I ass 
was employed for the fainter 
fainter. But no change of instrument was made during any sequence j that is 
f a sequence was begun at about 5« with the opera-glass, this L^lass was used to 
sequen 
stars of 6^ -or 
the lower limit of the sequence, even if it extended to below 6^ The obscr 
-tions were consistently made with the instrument placed 
expan 
ks of lig 
htly out of foe 
method, after repeated 
appear 
mg to give the most trustworthy results, especially for colored stars. Tl.e ob 
servatious were generally made during evenings free from 
and liaze, and between G" and 12'' mean time. 
;,■. ..v^ .luiu moonliglit, cloud 
