ASTRONOMY: E. DOOLITTLE 
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Class B. — The velocity shows a definite diminution. The stars are nearly 
at their maximum distance. Measures are now needed to fix the position 
of apastron, but the angle will probably change but little. The distance should 
be measured with special care. 
2 305, (1427) ;2 1457, (5508); 02 261, (6415); and 02 288, (7049) all show a 
decided and progressive diminution of the velocity. In the last, (02 288), 
it is, in fact, uncertain whether the motion did not wholly cease about 1912, 
and the two stars begin to draw together. 
Class C. — A systematic and certain variation of the velocity, but the com- 
panion is not certainly at either periastron or at apastron. 
The most striking examples in this class are: 2 400, (1747), in which the 
velocity has been steadily increasing since discovery; 02 215, (5365), in which 
the analysis shows the maximum velocity to have been attained about 1893; 
2 1865, (6955), in which the velocity mounted quite suddenly to a value nearly 
four times the average about 1897, when the stars were closest together, and 
which has since been rapidly diminishing, and 2 2118, (7834), in which the 
maximum velocity was attained about 1895. In all of these cases the rise and 
fall of the velocity is very striking. There were also found to belong to this 
class —2 2, (21);2 535, (216l);2 1536, (5765); and2 1687, (6296). 
Class D. — The velocity apparently varies, (sometimes quite irregularly), 
and orbital motion is strongly suggested, but it is in no case entirely certain. 
But few observations are required on these pairs at this time. 
Fourteen of the 48 pairs were found to belong to this class in which, though 
orbital motion might be strongly suspected, it is, nevertheless, not yet entirely 
certain. These pairs are, — 
2 13, ( 92), 02 159, (3678), 2 1757, (6530), 
2 138, ( 830), 2 1175, (4402), 2 2315, (8548), 
02 50, (1568), 2 1338, (5030), 2 2434, (8986), 
2 460, (1952), 2 1429, (5421), 02 413, (10533), 
2 1517, (5707), 02 437, (10922). 
Class E. — No certain trace of orbital motion. A multiplication of observa- 
tions on these pairs is unnecessary. 
Fifteen pairs showed no certain trace of orbital motion : 
H 1968, ( 216), 02 92, (2445), 2 1643, (6174), 
02 18, ( 374), H 3823, (3112), 2 1883, (7013), 
02 43, (1365), 2 1104, (4098), 02 297, (7320), 
2 367, (1623), 2 1423, (5385), 2 2199, (8118), 
2 567, (2272), 02 237, (5859), 2 2574, (9570). 
Summary. — The final summary for the 48 pairs examined is as follows: 
Class A 7 Pairs, Class B 4 Pairs, Class C 8 Pairs. 
Total pairs in which orbital motion is certain 19 
Class D .... 14 Pairs, Class E .... 15 Pairs 
Total pairs in which the evidence thus far is negative 29 
