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As long as no outside influence interferes with the regular procession of the planets, and the astronomer cannot foresee although he may admit the possibility of such interference, we may count upon our globe remaining a genial abode, neither too hot. nor too cold, though subjected to some vicissitudes of climate; and long before the next period of high eccentricity has blasted our fair continent with the chilling breath of the glaciers, the race of man may have had its day.

POGSON'S COMET AND THE BIELAN METEORS.

By W. H. S. MONCK, DUBLIN.

The story of POGSON's discovering a comet in the year 1872 is pretty well known. KLINKERFUES, after the great shower of Nov. 27th, 1872, telegraphed to POGSON, at Madras, that BIELA'S comet had touched the earth and asked him to look out for it near Centauri. POGSON did so as soon as the weather permitted 0 and saw a comet in the direction indicated on the 2d and 3d of December. Subsequent computations, however, led astronomers to conclude that BIELA'S comet could not have touched the earth on the day in question, nor if it had done so, would it have been seen in the place where a comet was observed by POGSON.

The reason, however, why KLINKERFUES placed the comet near Centauri does not seem to be so well known. The radiant point for meteors attached to BIELA'S comet is situated at about 25°, +44°. But KLINKERFUES deduced from the paths of SI meteors observed on the 27th of November, 1872, a radiant at 26°, +37°. He seems to have concluded from this radiant that BIELA's comet had changed its course and that its new path would bring it near Centauri; and the discovery of a comet. near that star by POGSON affords some confirmation of the correctness of KLINKERFUES'S radiant. It is true, indeed, that the majority of observers in 1872 placed the radiant nearer to 25°, +44° than KLINKERFUES, but the radiant is admittedly a very diffused one and it cannot be said that KLINKERFUES stands alone in his determination of it. SWIFT, at Rochester, N. Y., placed it at 26°, +39° during the latter part of the shower and DENZA placed one extremity of the radiant (which he described as an area) at 25°, +38°. From what we know of the break-up of BIELA'S

comet there is no improbability in its having thrown off at some earlier period the comet observed by POGSON; or if they never formed parts of the same comet, the comets of POGSON and Biela may belong to the same family and may co-operate in producing the same diffused meteor-shower.

Another great display of BIELAN meteors took place in 1885. It is natural to inquire whether any meteors from KLINKERFUES'S radiant were observed on that occasion. I find on the 4th of December, 1885, Mr. DENNING deduced a radiant at 31°, +37° from a number of slow-trained meteors of the BIELAN type, and he places November 30 and December 7 under the head of "other nights of observation." Dr. KLEIBER has computed parabolic orbits for all the radiants in Mr. DENNING'S catalogue and I find that his elements for this shower agree closely with those of the BIELAN shower a few days earlier. I give these elements compared with those of the shower observed at 24°, +44° on the 27th of November in the same year. These showers are numbered 819 and 851 in Mr. DENNING's catalogue.

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The motion in both cases is direct.

If POGSON'S comet was pursuing an orbit similar to that of BIELA'S it would nearly complete three revolutions in 20 years. If it was near the node in November, 1872, it would be a considerable distance from it in November, 1885, which would account for the feebleness of the shower noted by Mr. DENNING on the 4th of December in that year. But it ought to be again near the node about the 1st of December, 1892, when we might hope to detect the comet itself as well as a renewal of the meteor-shower which led KLINKERFUES to its discovery. It should, however, be mentioned that one of Mr. DENNING'S stationary or long-enduring radiants is situated very near 31°, +37°, which renders the connection of this shower with any comet somewhat problematical.

As POGSON obtained but two observations of the comet, no orbit could of course be determined from his data. But if the comet is one of short period like that of BIELA and the meteorshowers which I have mentioned were connected with it, some of

the skilled mathematicians who belong to this society may find the data sufficient for computation. A rough determination for the guidance of comet-seekers would answer all practical purposes.

HISTORICAL NOTE RELATING TO THE SEARCH FOR THE PLANET NEPTUNE IN ENGLAND IN 1845-6.

BY EDWARD S. HOLDEN.

In 1876 I was in England for several months and one of my greatest privileges was the acquaintance and friendship of Mr. LASSELL, the celebrated astronomer, whom I frequently visited. During one of my visits to Ray Lodge I learned the following circumstances from Mrs. LASSELL and they were subsequently confirmed and explained to me by Mr. LASSELL himself.

With the innate delicacy of his character he had taken every precaution that they should not become known during the lifetime of Professor ADAMS, and I think he seldom or never alluded to them. At this time, when the great mathematician has gone from us, it seems to be right that they should be mentioned and, with the permission of the Misses LASSELL, I reproduce in what follows the brief notes I made at the time of Mr. LASSELL'S confidences, as a contribution to the history of the great discovery of ADAMS and of LE VERRIER.

It is known that in October, 1845, Professor ADAMS, then an undergraduate of Cambridge, submitted to Sir GEORGE AIRY, Astronomer Royal, the results of his computations on the perturbations of Uranus and the elements of a new planet-Neptunewhich would account for the observed disturbances in the orbit of the former. The distinguished observer, the Rev. W. R. DAWES, visited the Royal Observatory about this time, and the letters and computations of ADAMS were shown to him by AIRY. It is known that the Astronomer Royal had, very naturally, grave doubts as to the sufficiency of these researches; but it appears that DAWES was much impressed by the letters of ADAMS, and that he at once wrote to LASSELL to beg him to search for Neptune, in the region designated by ADAMS, with his powerful two-foot reflecting telescope (which was then mounted at Starfield, near Liverpool).

There is no doubt whatever if such a search had been made *See GOULD on the History of the Discovery of Neptune. Washington, 1850.

by such an observer and with such a telescope, that the planet would have been quickly found and recognized by its disc. We have but to remember that to the same telescope and observer we owe the discovery not only of the satellite of Neptune but also that of the two inner and faint satellites of Uranus.

It chanced that the letter of Mr. DAWES reached Liverpool when Mr. LASSELL was confined to his sofa by a sprained ankle, and that it was laid on his writing table near by for subsequent attention. Mr. LASSELL, also, was impressed with the importance of a search for the predicted planet and had fully resolved to make such a search.

After his recovery he sought for the letter of Mr. DAWES which gave the predicted place of the planet. The letter could not be found as it, together with some other papers, had been removed and destroyed by a too zealous maid-servant.

I think, though I am not sure, that renewed inquiry was made by LASSELL of DAWES as to the data in question. However this may have been, they were never recovered, and the mistaken zeal of the maid-servant had its full effect.

The new 'planet was never sought for by the most powerful telescope and the most skilful observer in England. The search of CHALLIS, at Cambridge, was fruitless, as is well known. The planet was finally found by GALLE and D'ARREST, at Berlin, on September 23, 1846, after the Berlin Observatory had received the letter of LE VERRIER pointing out its situation.

This was many months after the letter of DAWES to LASSELL. This incident of the history of the search for Neptune is well worthy of record, as it shows by what a narrow chance Professor ADAMS escaped the distinction of being the sole discoverer of Neptune.

It is also worthy of remark how this and other accidents have helped to forward the Science of Astronomy. England had no higher rewards and opportunities to offer than those which she has given to ADAMS. But if LE VERRIER had been deprived of his share in the discovery it is very much to be doubted whether we should now possess that long series of elegant and laborious researches which he was able to carry out by the facilities afforded him in his situation as head of the National Observatory of France.

The whole relation of Professor ADAMS to this great discovery is again called up by this incident and the elevation of

his character and the dignity of his conduct are again brought to mind.

The delicate consideration of Mr. LASSELL, who for a long lifetime kept this secret in order that no possible shade of regret should be inspired during the lifetime of Professor ADAMS, is no less honorable. It is a pleasure to be able to link in this way the name of England's great mathematical astronomer with the name of her great observer-worthy successors of NEWTON and of HERSCHEL as they were.

MOUNT HAMILTON, January 30, 1892.

NOTE: By the great kindness of a friend in England I am able to reproduce here the last picture taken of Professor ADAMS, which was made in Cambridge in September, 1891.

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