Prof. Kirkwood on the Orbits of Binary Stars. 233 
Art. XXIII.—On the Orbits of Binary Stars; by Prof. DANIEL 
KirRKWooD, Bloomington, Indiana. 
more than 6000.’ The proportion of these in which t 
oy is merely optical cannot now be determined: the num- 
er, however, in which a change of relative position had been 
detected, was, at the middle of the present century no less than 
650. In the motions of these bodies, so far as observed, we fin 
one general and striking characteristic; the orbits are much more 
elliptical than those of our planetary system. In Sir John Her- 
schel’s Table (1850) of fourteen double stars whose orbits bad 
been calculated, the eccentricity in seven cases is greater than 
that of Faye’s comet (0°5559); while in the case of A/pha 
taurt it is nearly equal to that of Halley’s.”_ We propose to in- 
quire whether this remarkable fact in regard to the sidereal or- 
bits is susceptible of explanation by the nebular hypothesis. 
na former number of this Journal’ it was stated that the 
Tue whole number of double stars hitherto observed is rather 
h the du- 
. The components being less than 82’ asunder. , 
The eccentricity of ‘he former is 0°95; that of the latter, 0°9674. 
For September, 1860, p. 165. 
