Page:The story of the comets.djvu/115

VI. the comet had attained naked-eye visibility when discovered, coupled with the further fact that this region must have been repeatedly swept over by comet-seekers to within a few days of the discovery, shows that the comet must have rather suddenly attained its conspicuous visibility. When found this object was already some five months past perihelion, and had been theoretically for several months in a far better condition for discovery. From the care and skill shown by the large number of astronomers now engaged in comet-seeking, there can be no doubt whatever but that this comet did not exist during that time with anything like one-tenth of the brightness it had at discovery.

From this, and its subsequent remarkable behaviour, several astronomers argued that the object was not a comet in the true sense of the word, and that it must be the product of some celestial accident. This idea was further strengthened when its orbit was computed, and was found to lie within the asteroid zone. This orbit differed altogether from that of the ordinary comet by being almost circular. According to the orbit the comet ought to have been easily visible at every previous opposition and should have been discovered long ago.

It seemed highly probable at least that it should be seen at its next opposition when it would be very favourably placed for observing. Though carefully searched for, no trace of the comet could be seen with the 12-inch and the 36-inch of the Lick Observatory.

From the fact that the orbit lay out among the asteroids Corrigan and Kirkwood suggested that possibly two asteroids had collided and produced the phenomenon of a comet. However much faith may be placed in this hypothesis, I think, from the peculiar phenomena witnessed during the visibility of the comet, that it does not now exist in the cometary form, and furthermore, I do not think that it will ever be seen again, though it should return to perihelion in 1899. All the circumstances connected with it rather tend to show that it was of only a temporary nature.

The announcement of the discovery of this comet was received at the Lick Observatory on November 8, 1892, and it was observed that night with the 12-inch refractor. Its appearance was absolutely different from that of any comet I had ever seen. It was a perfectly circular and clean cut disk of dense light, almost planetary in outline. There was a faint, hazy nucleus with a slight condensation some 5" south following the nucleus. With the naked eye the comet was just as bright, exactly, as the brightest part of the Great Nebula of Andromeda, near which it was visible.

At 8h 0m a careful estimate of its diameter made it 260". At 9h 40m careful micrometer measures made the north and south diameter 286".

On November 9, at 6h 5m the comet was brighter to the naked eye than the brightest part of the Andromeda nebula. At 6h 20m the measured diameter was 337" north and south, with the 12-inch telescope; there was a faint diffused glow 12' in diameter surrounding the comet symmetrically and a short, faint diffusion south following. The nucleus preceded the centre about $1⁄2$ while at the centre there was a slight condensation. With the naked eye at 8h 0m the comet looked like a small star and almost equal in brightness to ν Andromeda, and could not be distinguished from a star. At 8h 30m it was looked at with the 4-inch comet-seeker the diffused haze could be seen surrounding it with faint traces of a tail."