Page:Popular Science Monthly Volume 22.djvu/304

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290
THE POPULAR SCIENCE MONTHLY.

waiting for clear weather again in hopes of being able to catch it on the meridian. This would put its discovery on or before September 7th. It was seen on the 8th by Mr. Finlay, an assistant in the Royal Observatory at the Cape of Good Hope; and on the 12th it was observed at Rio Janeiro, by Cruls, who telegraphed the news to Europe, announcing it (erroneously) as the expected comet of 1812 on its return. We have not yet sufficiently full accounts from the southern observatories to know whether it was lost sight of at all after its discovery, but we have the account of a most interesting and unprecedented observation made at the Cape Town Observatory, on the 17th. Mr. Gill, the director of the observatory, writes: "The comet was followed by two observers with separate instruments right up to the sun's limb, where it suddenly disappeared at 4h 50m 58s local mean time." This was about an hour and a half before its perihelion passage.

A few hours previously it had been independently discovered by Mr. Common in England, in the full blaze of sunlight, and clouds alone prevented him from making the same observation as Mr. Gill.

It is evident that the comet must have been most intensely brilliant to be visible under such circumstances. When it passed on to the sun's disk (it was between us and the sun at the time), it disappeared, being either transparent, or else practically as bright as a portion of the sun's own surface. If this comet had been in the place of the little "Tewfik" which was seen close to the sun at the time of the Egyptian eclipse last May, it would have been something to remember.

On September 18th the comet had reached a greater distance from the sun (about 3°), and had become so conspicuous that it was simultaneously rediscovered by a multitude of observers in all parts of the world, and accurate determinations of its position were made at several observatories. On the next day every one had heard of it, and people interested in astronomy thought and talked of nothing else.

On the 19th and 20th the comet was still easily seen by the naked eye. On the 21st it was visible only in places when the air was very clear, and the sky darkly blue. On the 22d a curious observation of it was made at Paris by M. Mallet, who, at the request of M. de Fonvielle, ascended for the purpose in a balloon provided by the latter, thus getting above the clouds with which the city was thickly covered. Of course, it was not possible in this manner to make any precise determination of position, but the aeronaut obtained a fine view of the celestial visitor.

For a few days after this the comet does not appear to have been observed until it had receded far enough from the sun to become visible before sunrise. Then, for a while, during the early days of October, it was a most magnificent object, with a head at first rivaling Jupiter in brightness, and a tail which, though not of unusual dimensions, never much exceeding 60,000,000 miles, was remarkably well defined, dense, and luminous. It moved slowly toward the south and