SCIENTIFIC SUMMARY. 
551 
part o£ the Alps as far as Plato, the Mare Imbrium is of a pure dark 
colour, the uniformity of tint being very remarkable, and not interrupted 
with bright patches, craters, and roughnesses, as in the other seas. 
Occultation of tlic Star Kappa Cancri on April 26. — Mr. Copeland (near 
Manchester), in observing the disappearance of this star at the moon’s 
dark limb, noticed that there was an interruption of its light. At first 
about three-fourths of its light disappeared instantly, and in the interval 
of half a second the remainer disappeared. This would seem to show 
that the star was double. The occultation of the star Alpha Scorpii, which 
is only visible as double to the most powerful instruments presenting 
the same phenomenon at occultation by the moon, Mr. Dawes has con- 
sequently examined Kappa Cancri with the hope of detecting this duplicity, 
but although seen pretty favourably and examined with magnifying powers 
of 620 and 1,000, the star seemed perfectly round. Occultations of this 
star occur on September 9 and November 30 of this year — the latter will 
be the most favourable for observation. It may be stated, however, that 
Mr. Burr observed the disappearance of this star on the same night at 
Highbury, and says that the star disappeared instantaneously. 
Sun's Parallax. — This important element — in other words, the dis- 
tance of the earth from the sun — has been lately determined by Mr. Stone, 
from a comparison of simultaneous observations of Mars and stars near 
him, made at the Greenwich and the Victoria (Australia) Observatories. 
The result gives 8,932 seconds, differing but little from the value found 
by M. Le Vender, but very considerably from that of 8,578 deduced from 
the celebrated transits of Venus of 1761 and 1769. 
Deviation in the Direction of Gravity. — The observed co-latitude of the 
Observatory of Moscow has been found to be eight seconds greater than that 
given by the geodetic survey ; and as there can be no doubt of the correct- 
ness of either, it clearly proves a local deviation. As there are no moun- 
tains in the neighbourhood, but it is a clear level country, this is the more 
extraordinary. 
Dark Ring of Saturn. — On March 26, 1863, Mr. Carpenter found a 
great increase in the brightness of the dusky ring of Saturn, which ap- 
peared to be nearly as bright as the illuminated ring. 
Glass Specula. — The Rev. Mr. Key has invented a new method of polish- 
ing the above, which from its success in the hands of amateurs promises 
excellent results. He polishes to a spherical figure first, and then modifies 
the figure of the polisher, with which, with the usual stroke and side-motion, 
he obtains the parabolic figure. By means of a 6J-incli aperture, Mr. 
With, of Hereford, has worked one which separates the components of 
the small star of Gamma Andromedse. 
Parallax of Stars. — M. Kruger has determined the parallax of two 
new stars of which M. Argelander had established the considerable proper 
motion. The first is Lalande, 21,258, for which the annual parallax has 
been found to be 0'2G0 seconds of arc. The second is Argelander’s star, 
17'415-G, for which he finds almost the same amount — viz., 0247 seconds. 
It is somewhat remarkable that both of those are stars invisible to the 
naked eye — the first being of the 8 4 and the second of the 9th magnitude. 
This would seem to show, which has already been established by 61 
