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POPULAR SCIENCE REVIEW. 
these stars, which lie about 12^ minutes of arc from each other. He finds 
that the annual proper 
motion of each star deducible 
from the Greenwich 
observations is : — 
InR. A. 
In N. P. D. 
A 1 Ophiuchi 
. -0-029 
+ 1"*20 
A 2 Ophiuchi 
. -0*043 
. +1 *05 
30 Scorpii . 
. -0*042 
+ 1 *17 
No doubt can remain that we have here a drifting system. 
Proper Motion of Oeltzen's Argelander 17,415-6. — Mr. Lynn estimates for 
the proper motion of this ninth magnitude star 
in R. A. - 0 s -07 
in N. P. D. + 1"*20 
Memoir by Hansen on the Transit of Venus. — Dr. Hansen deals chiefly in 
this paper with the possibility of obtaining the solar parallax by simple 
measurements of the distance of Venus from the sun’s centre at the moment 
of greatest phase. In the last of three appendices he exhibits formulae “ for 
the application of photographic observations to determine the parallax. The 
formulae require (besides the distance of the centres of the sun and Venus) 
the determination of the position-angles of Venus at the two stations respec- 
tively. It is suggested that there should be at the focus of the instrument 
a wire in the plane of the declination circle to be represented in the photo- 
graph, and thus to serve as a ground-line for the measurement of the position- 
angle; ” but Dr. Hansen is unable to judge of the degree of accuracy with 
which the position- angle can be thus determined. The difficulty disappears 
when observations are made upon the plan proposed by Mr. Proctor, for by 
his method only estimates of distance between the centres of Venus and the 
sun would have to be considered. 
Nautical Almanac for 1874, and the Transit of Venus. — In the recently 
issued “ Nautical Almanac for 1874 ” the phenomena of the transit of 1874 
are calculated for nearly all the suitable observing stations. Probably the 
tables dealing with these phenomena will be regarded as disposing finally 
of any doubts which may have been entertained respecting the accuracy of 
Mr. Proctor’s statements where these differed from the statements of the 
Astronomer Royal. For example, it was somewhat confidently stated that at 
Nertchinsk — which Mr. Proctor proposed as a suitable northern station for 
applying Halley’s method — the sun would not have both at ingress and de- 
gress of Venus anything like the elevation of 10° which had been pronounced 
necessary for effective observation ; whereas Mr. Proctor asserted that at 
both internal contacts the sun would have a sufficient elevation. The 
“ Nautical Almanac ” gives for internal contact at ingress a solar elevation of 
12°, and for internal contact at egress a solar elevation of 10°. In fact, so far 
as the “Nautical Almanac” tables extend, they confirm every one of Mr. 
Proctor’s statements in all essential points — differing only as to small details 
depending on the selection of the value of Venus’s semi-diameter and the 
sun’s. 
Planets for the Quarter . — Jupiter’s distance is gradually increasing, but 
he continues to be an evening star, and not unfavourably situated for obser- 
vation during the earlier part of the quarter. Saturn will be in opposition 
