THE PLANET JUPITER.

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many an observer would most certainly have called specialattention to it, if it had been as noticeable, or its colour asremarkable, before the year 1878, as since the summer of thatyear.

It is, however, very interesting to find, that various tracesof its previous existence have been recorded. For instance,the writer of this lecture has noticed, as he has mentioned inthe Observatory , vol. iii., p. 449, that some of the drawingsof the planet made in 1873, and published by Lord Rosse ,afford indications of its presence.* It is also a remarkablefact that, near to the same part of the disc, an elliptic form ofsimilar shape was frequently seen by Mr. G-ledhill and othersin 1869 and 1870.t But this was simply an outline ellipseformed by a narrow black line, the interior of which, with

Fig . LXX.—Jupiter, March 13th, 1872,

Fig . LXXI.—Jupiter, April 18th, 1872,

the exception of an occasional streak across it, was as bright asthe surrounding portions of the disc.

More recently, however, Mr. H. C. Russell, F.R.A.S., of theObservatory, Sydney , N.S.W. , has stated } that he finds, ongoing through his drawings made during the last few years?that he had frequently observed it in 1876, when it wasinvolved in the equatoreal colour-band of the planet and some-what different in shape, but not in colour, from its subsequent

* See R. A. S. Monthly Notices, vol. xxxiv.

t See Astronomical Register, vol. ix., p. 249 ; and vol. x., frontispieceand p. G8.

f See. “Recent Changes in the Surface of Jupiter,” a paper readbefore the Royal Society of N. S. Wales, December 1880, by Mr. Russell.