THE SUN.

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successive envelopes or strata, further removed from its centre,which are called respectively the inner and the outer corona.These are only visible during total eclipses. At other timestheir light is not sufficient, either for spectroscopic obser-vations, or for those made with a telescope. But duringthe totality of an eclipse, very useful and interesting-information may be obtained with regard to them. It isthen easily seen that the photosphere is surrounded by a bril-liant region, the lower part of which, although more or lessirregular in its boundary, is somewhat distinctly defined, andextends to a height which does not in general exceed 300,000miles. The outer portion is much more irregular in its shape,and is frequently prolonged, especially in the neighbourhoodof the Sun’s equator, into the form of immense rays orstreamers, which under favourable circumstances may betraced to a distance of at least 10,000,000 of miles.

We have much pleasure in putting before our readers a re-production, by the Woodbury process, of a most beautiful steelengraving, published in vol. xli of the Memoirs of the RoyalAstronomical Society (commonly called the Eclipse Volume),which was compiled and edited with extraordinary care byMr. Ranyard, late Secretary of the Society . It represents thetotal eclipse of 1871, and is a copy by Mr. Wesley, the veryable Assistant Secretary of the Royal Astronomical Society , ofa drawing made from the original negatives photographedduring the eclipse in connection with Lord Lindsay’s expeditionat Baikul. We know of no view in which a more beautifuland interesting amount of detail is depicted in the Sun’ssurroundings. Nothing, however, has been inserted which wasnot visible in at least three of the negatives taken. Thegeneral effect of the original will be best obtained by holdingthe Woodbury-print between twelve and eighteen inches fromthe eye.

During an eclipse the spectroscope indicates that the lightof the corona is partly derived from solid matter, or frommatter which gives the same kind of spectrum as that whichis solid; but that it also consists to a considerable extent ofluminous gas, a large portion of which appears to arise from