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SCIENTIFIC SUMMARY. 
QUARTERLY RETROSPECT. 
ASTRONOMY. 
D URING the long nights of the winter months, the telescopic observer 
is much busier than at other seasons of the year ; and although the 
present quarter has been far from favourable, yet a few discoveries have 
been made which are somewhat important. M. D’Arrest has inaugurated 
the erection of a large Munich refractor, at Copenhagen, by the discovery 
of the seventy-sixth individual of the group of planets revolving round 
the sun between Mars and Jupiter. His successor at the Leipzic Obser- 
vatory — M. Bruhns — has signally distinguished himself as the discoverer 
of two comets within a few hours of each other, and thus proved that this 
branch of astronomy is equally safe in his hands as in those of M. D’Arrest, 
so famous for his successful search after those bodies. In this, however, 
M. Bruhns is only following up his previous well-earned renown at the 
Berlin Observatory, where he detected many comets. By the public in 
general those discoveries are looked upon as the result of chance ; but this 
is far from being the case, the search being as systematic as any that can 
possibly take place under the circumstances. Previous to finding either a 
planet or comet, the sky has to be sounded, surveyed and triangulated with 
the greatest accuracy — variable stars and nebuke avoided, and marked 
with as great care as the rocks and breakers of the ocean — and the result 
has been that within the last ten years the maps of the smaller telescopic 
stars are far more correct than those which are visible to the naked eye. It 
would appear probable that the list of planets is now nearly full, — the per- 
fection of the star-maps does not seem to have any effect in adding to their 
number, although it is by this perfection that any loose straggler is in 
momentary danger of being detected. Of late years, those planetary 
“nuggets” have been found few and far between, contrasting strongly 
with the rich harvest gathered some years since by Mm. Hind, Gold- 
schmidt, and Gasparis. In regard to comets the case is otherwise, and we 
may always expect an average annual supply of those bodies. In con- 
sequence of cloudy weather and moonlight, neither of the new comets has 
been favourably seen in this country, so that we must defer any further 
notice of them for the present. 
Daphne . — The planet Daphne has been searched for during the last 
three or four years with great anxiety, but no tidings heard of it until the last 
few months, when Dr. Luther detected an object of the eleventh magnitude 
