from The Eclectic Magazine, 1873

(page 592)

But on one occasion a very remarkable phenomenon, only (but very readily) explicable in this way, was witnessed by three practised observers—Admiral Smyth, Professor Pearson, and Sir. T. Maclear—at three different stations. Admiral Smyth thus describes what he saw:

"On Thursday, June 26, 1828, the evening being extremely fine, I was watching the swecond satellite of Jupiter as it gradually approached to transit Jupiter's disk. It appeared in contact at about half-past ten, and for some minutes remained on the edge of the disk, presenting an appearance not unlike that of the lunar mountains coming into view during the moon's first quarter, until it finally disappeared on the body of the planet. At least twelve or thirteen minutes must have elapsed, when, accidentally turning to Jupiter again, to my astonishment I perceived the same satellite outside the disk! It remained distinctly visible for at least four minutes, and then suddenly vanished!"

For our own part, we can conceive of no possible explanation of this remarkable phenomenon, unless it be admitted that the change was in the apparent outline of Jupiter. Of course, to suppose that even a cloud-layer rose or fell, in a few minutes, several thousand miles (about 8,000, if the stated times be correct), is as inadmissable as to suppose the solid crust of a globe to undergo so vast a change of level ...