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POPULAR SCIENCE REVIEW. 
and, on the part of the latter, of some little asperity; after which the 
enquiry seemed to languish till it was taken up by De Vico, but still left 
in a position hardly corresponding with our advance in the knowledge of 
most of the other planetary surfaces. There is no doubt considerable diffi- 
culty in the investigation ; and failures, even with large aud powerful 
instruments, have been numerous. No question, however, exists as to the 
occasional visibility of brighter specks, and still more frequently of dusky 
shadings, which stand on multiplied testimony ; and there is no adequate 
reason for not adopting the numerous representations given by De Vico and 
his associates at Rome, from their observations between 1839 and 1841, 
with a 6L-in. object-glass by Cauchoix, and in a sky of whose pellucid 
clearness we can form very little idea in the perturbed and agitated con- 
dition of the English atmosphere. It seems strange, however, that these 
results should never have been verified at the same observatory with the 
very superior 9^-in. Merz achromatic in the hands of so eminent an astro- 
nomer as Secchi ; nor have they, so far as we are aware, ever been continu- 
ously investigated elsewhere. It is very true that the enlarged apertures of 
the present time, however keen in definition, are baffled to a great extent 
by the intense glare of this vividly reflective globe ; but it is no less true 
that this disadvantage might be obviated by the use of a pale screen-glass, 
or by employing the hours of daylight, which indeed De Vico found alone 
suitable for his purpose. And where there are so many instances of 
the occasional detection of these spots, even with very small apertures, 
there is much encouragement for the perseverance of amateurs. 
The Recent Transit. —The reduction of the English observations is pro- 
ceeding vigorously under the superintendence of Captain Tupman. The 
amount of work involved has been marvellous. About 5,000 transits of stars 
were taken for the correction of clock and instrumental errors. The longi- 
tudes of the stations at Mauritius and Rodriguez were measured from Suez 
by Lord Lindsay with fifty chronometers ; and Mr. Burton has made more than 
6,000 microscopic measures to determine the optical distortion of the photo- 
heliographs. It is self-evident that a considerable time must elapse before 
the final result, even of the British observations, can be made known ; and 
it is not as yet decided whether a separate value shall be deduced from 
these, or whether they are to be combined with the results of all other 
nations. 
The Moon . — The investigation of the surface of our satellite, if we may 
judge by the number of published observations, makes no very rapid 
advances, and seems to be little attended to at the principal European 
observatories. Several amateurs, however, are doing good service in work- 
ing out details. Many interesting points remain to be discussed as to the 
probable mode of formation of the lunar surface ; in fact, very little has 
hitherto been done in what may be termed selenology. The materials 
are as yet not very abundant, but sufficient perhaps for a rough draught, 
which would be tested and corrected by future observation. There can be 
little reason for doubting that the key to the lunar configurations lies in the 
analogy of the eruptive processes of the earth ; but important modifications 
would necessarily be introduced by the dissimilar conditions of the two 
globes — by the great difference in the force of gravity, in atmospheric 
