middle of July, 1826. It was most conspicuous at the beginning of October, when the head was approaching our southern horizon. The tail appeared about 15° long, and was divided into two branches. On the 6th of this month, Professor Santini saw the nucleus composed of three bright points. The period of revolution of this fine comet, is probably not less than 4000 years. It is known as the 'great comet of 1825,' several others having appeared in the same

year.

1843. The finest comet of the present century was that which made its appearance at the end of February, 1843. On the 28th of that month it was observed in full daylight near the sun, at Guadaloupe y Calvo, in Mexico; at Portland, in the United States of America; on board the East India Company's ship, Owen Glendower, off the Cape of Good Hope; and at Parma, Bologna, Genoa, and other places in Italy. It presented a most splendid appearance during the first week in March throughout the southern hemisphere, but when it became suddenly visible above the horizon in these latitudes, about the 17th of that month, its brilliancy had very much diminished: nevertheless the tail still covered an arc of the heavens of no less than 40°, and was curved towards the extremity. Undulations similar to those recorded in the trains of some of the great comets of past times were generally remarked. The suddenness of its apparition in this country added not a little to the interest which such an object was certain to excite. No accounts from more southern latitudes reached us for some days, and even astronomers were somewhat puzzled as to the nature of the

strange ray of light which, rising above the clouds or haze of the western horizon, soon after sunset, stretched over the south-west sky towards the constellation Lepus through more than 35°. The nucleus of this comet is described as small, but extremely bright, of a golden hue, of the colour of Venus, or reddish, according to different observers. On the 11th of March it exhibited a well-defined planetary disk, which, by accurate measurement, must have exceeded 4500 miles in diameter. The average length of the tail in March was about 35°, but on the evening of the 3rd a faint ray extended as far as 65° from the nucleus. At this time the train is described by an observer at Brazil as of a brilliant silver colour, but with a streak of a bright golden hue running directly into it from the head to an extent of four or five degrees. Early in the month it was divided into two branches, which subsequently united into one long narrow stream of light.

The orbit of this comet approaches closer to the sun than that of any other hitherto observed, not excepting the famous comet of 1680. According to the most trustworthy calculations, the perihelion distance was only 538,500 miles; therefore the centre of the comet would be distant from the surface of the sun's globe less than 96,000 miles!

Several comets have been mentioned as probably identical with the great one of 1843, and in particular those of 1668 and 1689, which exhibited tails of unusual length. If it were one and the same comet that appeared in 1668, 1689, and 1843, the period of revolution could differ but little from twenty-two

years. But, independently of the prima facie improbability of this short period, the evidence afforded by the history of comets in past ages is decidedly against it. Neither is the period of thirty-five years, suggested by some astronomers, more probable, for the comet of 1106 which was cited as strongly supporting this time of revolution, could not possibly have been the same as the comet of 1843, since historians agree in stating that it was observed for some time in the northern heavens, a circumstance perfectly irreconcilable with the elements of the latter body, which can only remain about three hours north of the ecliptic. Calculation shows that the paths of the comets of 1668 and 1689 might be tolerably well represented by the orbit of the comet of 1843, but equally well, in the former case, and much nearer in the latter, by numbers altogether different, so that we can come to no definite conclusion on the subject.

CHAPTER X.

ON THE EXPECTED GREAT COMET.

ONE of the grandest comets mentioned in history is that which made its appearance in the middle of the year 1264. It is recorded in terms of wonder and astonishment by nearly all the historians of the age: no one then living had seen any to be compared to it. It was at the height of its splendour in the month of August, and during the early part of September. When the head was just visible above the eastern horizon in the early morning sky, the tail stretched out past the midheaven towards the west, or was fully 100° in length. Both Chinese and European writers testify to its enormous magnitude. In China the tail was not only 100° long, but appeared curved in the form of a sabre. Its movement was from Leo, through Cancer and Gemini, into Orion. It continued visible until the beginning of October, historians generally agreeing in dating its last appearance on the 2nd of October, or 'on the night of the death of Pope Urban IV, of which event it seems to have been considered the precursor. It would lead us beyond the limits of the present work, were we to attempt to discuss the

rude accounts which have descended to us; we must, therefore, content ourselves with stating that some rough approximations to the elements have been attempted in the first instance by Mr. Dunthorne, in the middle of the last century, and subsequently by M. Pingré, the well-known French writer upon the history of comets.

In 1556, at the latter end of February, or early in March, a comet became visible in the zodiacal constellation Virgo. It was closely watched at Vienna, by Paul Fabricius, astronomer at the court of the Emperor Charles V., and we have a rudely executed map of its path amongst the stars in the Book of Prodigies, Omens, &c., published by Lycosthenes or Conrad Wolfhardt, at Nuremburg, in the year of the comet's appearance. It was not nearly so conspicuous as that of 1264, but still is described as a 'great and brilliant star.' Its course lay through Virgo and Bootes, past the pole of the heavens, into Cepheus and Cassiopea, where it was last seen about the end of the third week in April, according to European authorities, though the Chinese observers, who paid great attention to comets, did not lose sight of it till the 'second day of the fourth moon' corresponding to May 10th old style they discovered it on the 1st of March, a little below the equator, amongst the stars of Virgo.

Our countryman Dr. Halley, the second astronomer royal, calculated the elements of the comet of 1556, from the observations of Fabricius, and gave them, with many others, in his synopsis of Cometary Astronomy, which was published early in the eighteenth century.

Owing to the imperfect nature of these observations,