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POPULAR SCIENCE REVIEW. 
regards the delineation of the nebula, I cannot make out anything. It is 
impossible for us to publish maps in this state.” We have spoken of Pro- 
fessor Airy’s examination of the subject as final ; but as a matter of fact, a 
letter from Captain Herschel reopens the very question on which the Astro- 
nomer Royal had expressed himself satisfied. “ Mr. Abbott appears to have 
got wrong,” says Captain Herschel, “ in his N. and S. points. Is it rash to 
suspect that he has also mistaken i] ? Neither does he appear to have even 
recognised the lemniscate. He speaks of 1 a dispersion of the stars ’ ; but his 
own drawing, as I now show, places most of his stars in approximately their 
right relative places. Surely all this betokens non-recognition , on his part , of 
the object he was examining , due probably to an inferior magnifying power. 
If his chart of the stars is as correct as I think, every atom of evidence of 
change in the nebula which he adduces is swept away.” 
To quote the remark with which Professor Airy opens his paper, 11 The 
subject is a very puzzling one.” 
Proposal for a Series of Surveys of the Star Depths. — Mr. Proctor, in a 
communication to the Royal Astronomical Society, indicates the necessity 
of a series of systematic surveys of the heavens, on a principle quite different 
from that on which the Herschels gauged the star depths. A series of tele- 
scopes of gradually increasing aperture should be employed to gauge every 
portion of the celestial sphere, the series of gauges for the several apertures 
being then charted isographically. His opinion of the value of such surveys 
is founded on the interesting results which are established by the isographic 
charting of all Argelander’s series of 40 full-sheet charts, showing the places 
of 324,198 stars. It would not be necessary, however, to mark in every star 
separately, with careful reference to position and size, as in the isographic 
copy of Argelander’s charts ; all that would be necessary would be to mark 
in the observed number of stars (as determined by the gauges) in the corre- 
sponding spaces in the chart. The gauge fields should not be circular, but 
square (except close by the poles), so as to leave no ungauged spaces, and to 
avoid overlaps. By taking apertures of 3, 4, 5, 6, 8, 12, and 18 inches, or 
even to 2 ft. and 4 ft., a progressive series of charts would be obtained, 
which would throw great light on the laws of stellar distribution. 
The Physical Changes of Jupiter. — Mr. Ranyard has contributed an inte- 
resting paper on this subject to the u Monthly Notices ” of the Astronomical^ 
Society. He shows that, within two years of the great sun-spot maximum 
of 1848, the white spots on the southern belt were strongly marked, and 
the equatorial region much broken up. Within a year of the next sun-spot 
minimum, Mr. De la Rue made his large and well-known drawing of 
Jupiter with a 13-inch silver speculum. “It is full of the smallest details 
in the belts, yet there are no traces to be found of Dawes’ markings, bright 
points, northern or southern eggs (sic), or equatorial port-holes.” (We take 
some exception to these terms, as thus used absolutely; though they are 
very suitable expressions for comparative description.) Drawings made by 
Piazzi Smyth in 1856 entirely endorse Mr. De la Rue. But in 1858, when 
the sun was again marked with spots, Lassell noticed a numerous group of 
white spots in the bright equatorial region of Jupiter. 11 For several 
years,” says Mr. Lassell, 11 1 failed to see any such spots upon the face of 
Jupiter at all, but last year they appeared again in the same quarter of the 
