Biela'sX

lost comet, known to astronomers as Biela's A score of years had passed since this famous, though small, comet had been seen. In 1866, and again in the autumn of last year, astronomers had searched for it with special care, because, according to their calculations, it should have been favourably placed for observation. But not a trace of it had been detected. Then the expectation arose that as the earth was to pass, during the last week in November, through the track or wake of the comet, a meteoric display might be seen, even as had happened year after year when on November 13-14, 1866, 1867, 1868, &c., the earth passed through the track of Tempel's Comet. This anticipation was actually fulfilled, and it was readily shown that all the circumstances of the star-shower agreed with the theory that the falling stars were travelling in the path of the missing comet.

But a singular event followed. A German astronomer conceived the idea that as the comet's meteor-train had come as a star-shower from out of the north,' the meteors might be looked for as a cloud passing away towards the south. He telegraphed to an English astronomer occupying a station where the southern skies can be observed, and urged him to examine the part of the heavens directly opposite to the feet of Andromeda, whence the meteor shower had seemed to rain upon our northern regions. It was done and lo! close to the very spot pointed out there was a faint celestial cloud, resembling in all respects a small comet. It was watched, and seen to be travelling

in a course corresponding with that which the lost comet would have followed if travelling on that part of its path. In fact, the English astronomer announced definitely that he had found the comet which had been so long missing.

But it was not so. He had indeed found a nebulous cloud of light travelling in the track of the lost comet; but when enquiry came to be made by comet-calculating astronomers, it was seen that the cloud which had been seen in the south was far behind Biela's comet-millions of miles, if we count by distance, and nearly a quarter of a year, if we count by time.

Biela's comet is therefore still missing, though it cannot be said that we have seen nothing of it. Those meteoric visitants had undoubtedly once belonged to it; that cloud of light travelling southwards was unquestionably a portion of it, not a fragment recently detached (for such a fragment would not quickly be left so far behind), but a portion, which, many centuries ago, must have formed part of the long lost comet.

But how strange are the thoughts suggested by these circumstances! The history of Biela's comet had long been remarkable in cometic annals. In 1832 the comet had terrified the nations, because astronomers had announced that it would cross the earth's path.1 In 1846

The account of the terror then excited is very remarkable. The anxiety experienced in France led a Parisian Professor to beg the Academy of Sciences to refute the assertion that the comet would encounter the earth.

it divided into two separate comets, which travelled side by side with a gradually increasing distance between them, and with a singular interchange of light, now one onw the other being the brighter. In 1852 the comet returned yet again to our neighbourhood (the period in which it circles around the sun being about six years and eight months); and at that time the two companion comets could still be discerned, though the distance between them had enormously increased. Whether it returned in 1858-9 is not known, as its arrival on that occasion would have carried it to parts of the sky too close to the sun for telescopic scrutiny. In 1866, however, it should have been seen. Astronomers had become very familiar with the calculation of its motions, their predictions. according better and better at each return with the actual motions of the comet; and the path assigned to it was so placed that the comet should have been well seen. But

'Popular terrors,' he wrote (I quote from Dr. Dick's 'Sidereal Heavens '), 'are productive of serious consequences. Several members of the Academy may still remember the accidents and disorders which followed a similar threat, imprudently communicated to the Academy by M. de Lalande, in May 1773. Persons of weak minds died of fright, and women miscarried. There were not wanting people who knew too well the art of turning to their advantage the alarm inspired by the approaching comet, and places in Paradise were sold at a very high rate. The announcement of the comet in 1832 may produce similar effects, unless the authority of the Academy apply a prompt remedy; and this salutary intervention is at this moment implored by many benevolent persons.' Recently an announcement of a similar kind, relating to the arrival of a comet on August 12, 1872, was received (so far as I have been able to learn) with exemplary equanimity. Certainly no 'places in Paradise' were disposed of on this

occasion.

though carefully sought for with large and powerful telescopes, it was not then found; nor again was it seen on its return last autumn.

Let us follow the comet in imagination as it passed away from our neighbourhood in the year 1852, and try to conceive the dangers and vicissitudes to which it has been exposed, and to some one or other of which it may perchance have fallen a victim.

Biela's comet always arrived from out the north, and passed away from our neighbourhood southwards. Its course did not carry it very much nearer to the sun than our earth is; and, after passing southwards, until it was about eighty millions of miles from him, it gradually receded again, still passing farther and farther south of the general level in which the planets travel. For aught that is known, however, it may have been in this part of its course that the comet experienced the disturbances which so dissipated its substance as to render it undiscernible by terrestrial astronomers. We have reason to believe that meteoric systems are more and more densely strewn the nearer the sun is approached, that they cross and interlace in wonderfully complex fashion close by him; and it may have been in its passage through such labyrinthine meteor-systems that the comet lost its head in the most literal sense of the words. Such was the opinion of our great astronomer, the younger Herschel, who, writing in 1866, when the comet was first missed, said, 'Peradventure it has plunged into and got bewildered

among the rings of meteorolites.' All that we know of the structure of a comet's head teaches us to believe that, minute and scattered as are the meteors comprising such rings, they are quite sufficiently compact to effect the destruction of a comet impinging full upon one of their clustering aggregations.

But let us suppose that the comet escaped this danger -and, in any case, we know that what has here been spoken of as destruction is not absolute annihilation, but only the destruction of the cometic form: it passed on, let us imagine, unscathed by the meteors which crowd round the sun's neighbourhood, and, gradually increasing its distance, it bore away towards those cold regions of interplanetary space which lie beyond the orbits of the earth and Mars. Obeying the mighty reining power of the sun's attraction, the comet travelled on its oval path, sweeping far to the south of the orbit of Mars, and presently, as its distance still increased, it began to return towards the general level in which the planets travel. What strange news would that comet have to tell, if it could describe all the scenes through which it passed in this portion of its path!

Meteor-streams unknown to terrestrial astronomers travel in countless thousands in those spaces. Isolated bodies, like those aerolitic masses which fall from time to time upon the earth, are moving hither and thither on their paths round the sun. And yet more wonderful must be the scene presented by the solar system itself, and the