Astronomy. — “The Orbit of Bu 6832 = X 1834”. 
By W.H. van pen Bos. (Communicated by Prof. W. pe SirrEr). 
Communication from the Observatory at Leiden. 
(Communicated at the meeting of June 25, 1921). 
In the present investigation a preliminary orbit is determined of 
+1834. It is as yet scarcely possible to derive reliable orbital 
elements for this double star. 
The difference in magnitude being very small, the quadrant 
becomes doubtful about the time of periastron-passage. The same 
difficulty occurs in the well-known binaries & Scorpii and § Boötis, 
the first of which has been investigated by T. N. Trirre (Astr. 
Nachr. 1199, Bd. 50), the second independently by Airken (Publ. 
Astron. Soc. Pacific, Vol.: XXVIII N°. 165) and Hertzsprune (Astr. 
Nachr.- 4871, Bd. 203). 
In both cases however the binary character of the motion was 
certain, whereas in the case of = 1834 the assumption of uniform 
rectilinear motion has been investigated only three years ago by 
Prof. DoomrrLe (Astr. Journ. Vol. XXXII Nr. 746), though Lewis 
in his volume on the Struve-stars already pointed out the proba- 
bility of orbital motion. DoourrL« finds both curvature of the path 
and acceleration along the path. 
At present there can no longer be any doubt, that the companion 
is again in the second quadrant. In Vol. XXXI, Nr. 180 of the 
Publ. Astr. Soc. Pacific Prof. Airken gives measures of the pair, 
confirming the binary character. He says, that in the best two 
nights the following star seemed to be somewhat fainter. I noticed 
the same on a splendid night this year. But we must not have too 
much confidence in such statements. There are however more serious 
objections against the supposition, that the companion is still in the 
fourth quadrant at present. 
If we plot the position-angles and distances up to 1892 against 
the time, and derive normal places for 1830, ’40, ete. 1890 by a 
graphical adjustment, these places not only exhibit a distinct curva- 
ture and acceleration, but also show the impossibility of placing 
the recent observations in the third and fourth quadrant. Moreover, 
if we consult the measures between 1893 and 1914, we see that 
