"Its general course was inclined 15° or 20° to the right of a vertical circle, but the angle progressively decreased, and must have been very small towards the last. When first seen, it must have been near the body of Cygnus, and thence it followed, as nearly as could be estimated in so great a surprise and so strong a moonlight, the track of the west branch of the Galaxy, between Altair and Ophiuchus. The whole duration may have been as much as 5 seconds. Its aspect was decidedly that of a liquified and inflamed mass, and the immediate impression was that of rapid descent; but as its apparent magnitude diminished so much, with little comparative change of form, it is not improbable that it was in reality moving in a course not greatly inclined to the surface of the Earth c."

If we classify the apparition of all the fireballs the dates of which are known, we find, according to Arago, that their number amounts to 813, distributed as follows:

Thus shewing that the periodicity which prevails with the aërolites also obtains with the fireballs, only in a much more marked manner.

Of the above 813 fireballs of which we possess any recorded account, 35 only gave rise to aërolites the fall of which was actually witnessed. Small though this proportion undoubtedly is, yet we cannot but consider these 2 classes of phenomena to be intimately associated. It is, however, true, that cases have been known in which aërolites have fallen, which were not preceded by any luminous exhalation: an instance occurred on Sept. 16, 1843, at the fall of the great aërolite of Kleinwenden d.

Many fireballs have been submitted to measurement as regards their size and distance; but, owing to the very sudden appearance, and in general the short visibility of these bodies, it seldom happens that the observer is able to attain to any great precision. The following results must therefore be received with caution.

Letter in the London Review, Nov. 16, 1861. d Compt. Rend., vol. xxv. p. 627.

1. As to the height at the instant of apparition.

The average velocity of 66 meteors, calculated by A. S. Herschel,

is 344 miles per second.

It is desirable to remark that the velocity of any part of the terrestrial equator due to the axial rotation of the Earth is 1526 feet per second, and that the Earth's orbital motion is 18.2 miles per second. We see, moreover, that the velocity of many of these fireballs is greater than that of any of the planets; it is also worthy of mention that the general direction of their motion is contrary to that of the Earth".

A catalogue of 854 fireballs is given in Arago's Ast. Pop., vol. iv. pp. 230-279, French ed.

CHAPTER III.

Shooting stars.-Have only recently attracted attention.-To be seen in greater or less numbers almost every night.-Tabular summary of the results of the observations of Coulvier-Gravier and Saigey, and Schmidt.-Early notices of Meteoric Showers.— Shower of 1799.—Showers of 1831, 2, and 3.—The Meteors of 1833 divided into 3 groups.-The Shower of 1866.--Table of apparitions.—Singular result.—Olmsted's theory.-Herschel's theory.-Radiant points.

SHO

HOOTING stars, although noticed in former times, have only within the last half century attracted any particular attention. This branch of the science may therefore be considered to be comparatively in its infancy. We must possess a long and carefully made series of observations before we are likely to be acquainted, with any degree of precision, with the physical nature of these objects. They were formerly considered to be merely atmospheric meteors, caused by the combustion of inflammable gases. This opinion has, however, lost much, if not all, of its force, and they are now recognised as bodies, which, although they become inflamed on coming in contact with the Earth's atmosphere, yet have their origin far beyond it.

It is now an established fact that there is no night throughout the year on which shooting stars may not be seen; and that, on an average, from 5 to 7 may be noticed on a clear night every hour. These occasional meteors may be termed sporadic, in contradistinction to those swarms which appear at certain times of year, and which are periodic. There is, moreover, an horary variation in their number, and the maximum occurs at 6 A. M., the

the

mean at midnight, and minimum at 6 P.M., as shewn by the

If we designate the numbers coming from the N., E., S., W., by those letters respectively, we find E. > 2 W., N.= S. nearly, and that E.+W. N. + S.

The following table contains the monthly mean of the hourly number of shooting stars as assigned by 3 eminent Continental observers b:

Notwithstanding the discordances in the above results, both tables agree in showing that there are more shooting stars in the a than in the 1st half of the year-a coincidence which we have already seen holds good both with aërolites and fireballs. This has also been confirmed by the observations recorded in the Chinese annals,

AMA ARAN, vol xvii. p. 1473 That Avy Aveyden asce w Atoiles plantes,

b Quoted in Arago's Pop. Ast., vol. ii. p. 505, Eng. ed.

I now come to speak of the well-known and very beautiful showers of shooting stars seen at certain seasons in such great abundance. One of the earliest notices we find in history of this phenomenon is by Theophanes the Byzantine historian, who relates that in November 472 A.D. the sky at Constantinople appeared to be on fire with flying meteors. Condé, in his history of the dominion of the Arabs, speaking of the year 902 A.D., states that in the month of October, on the night of the death of King Ibrahim-Ben-Ahmed, an immense number of falling stars were seen to spread themselves over the face of the sky like rain, and that the year in question was thenceforth called the "Year of Stars.' In some Eastern Annals of Cairo it is related that: “In this year, in the month Redjeb [August 1029] many stars passed, with a great noise, and brilliant light;" and in another passage it says: "In the year 599, on Saturday night, in the last Moharrun [Oct. 19, 1202], the stars appeared like waves upon the sky, towards the east and west; they flew about like grasshoppers, and were dispersed from left to right; this lasted till daybreak: the people were alarmed." It is also recorded that a remarkable display took place in England and France on April 4, 1095. The stars seemed "falling like a shower of rain from heaven upon the Earth," and an eyewitness, having noticed where an aërolite fell, "cast water upon it, which was raised in steam with a great noise of boiling." In the Chronicle of Rheims we read that the stars in heaven were driven like dust before the wind, and Rastel says that: "By the report of the common people in this kynge's time [William II] divers great wonders were sene: and therefore the kynge was told by divers of his familiars that God was not content with his lyvyng; but he was so wilful and proud of mind, that he regarded little their saying."

In modern times, the earliest shower of falling stars of which we have any detailed description is that of Nov. 13, 1799, visible throughout nearly the whole of North and South America: it was seen even in Greenland by the Moravian missionaries. Humboldt, then travelling with M. Bonpland, in South America,

• An interesting catalogue by Newton, will be found in Silliman's Journal, vol. xxxvii. p. 389, vol. xxxviii. p. 53, May and July, 1864.