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 been no brilliant display upon which to test its capacity. Really large meteors can be satisfactorily photographed, but small ones leave no impression on the plates.

Meteors look larger than they are, from the glare and flaming effect due to their momentary combustion. The finer meteors on entering the air only weigh a few hundred or, at most, a few thousand pounds, While the smallest shooting stars visible to the eye may probably be equal in size to coarse grains of sand, and still be large enough to evolve all the light presented by them.

 METEORA, a group of monasteries in Thessaly, in the northern side of the Peneius valley, not quite 20 m. N.E. of Trikkala, and near the village of Kalabaka (the ancient Aeginium, medieval Stagus or Stagoi). From the Cambunian chain two masses of rock are thrust southward into the plain, surmounted by isolated columns from 85 to 300 ft. high, “some like gigantic tusks, some like sugar-loaves, and some like vast stalagmites,” but all consisting of iron-grey or reddish-brown conglomerate of gneiss, mica-slate, syenite and greenstone. The monasteries stand on the summit of these pinnacles; they are accessible only by aid of rope and net worked by a windlass from the top, or by a series of almost perpendicular ladders climbing the cliff. In the case of St Stephen’s, the peak on which it is built does nor rise higher than the ground behind, from which it is separated by a deep, narrow chasm, spanned by a drawbridge. Owing to the confined area, the buildings are closely packed together; but each monastery contains beside the monks’ cells and water-cisterns, at least one church and a refectory, and some also a library. At one time they were fourteen in number, but now not more than four (the Great Monastery, Holy Trinity, St Barlaam’s and St Stephen’s) are inhabited by more than two or three monks. The present church of the Great Monastery was erected, according to Leake’s reading of the local inscription, in 1388 (Björnståhl, the Swedish traveller, had given 1371), and it is one of the largest and handsomest in Greece. A number of the manuscripts from these monasteries have now been brought to the National Library at Athens. Aeginium is described by Livy as a strong place, and is frequently mentioned during the Roman wars; and Stagus appears from time to time in Byzantine writers.

See W. M. Leake, Northern Greece (4 vols., London, 1835); Professor Kriegk in ''Zeitschr. f. allg. Erdk. (Berlin, 1858); H. F. Tozer, Researches in the Highlands of Turkey (1869); L. Heuzey and H. Daumet, Mission archéologique de Macédoine (Paris, 1876), where there is a map of the monasteries and their surroundings; Guide-Joanne; Grèce'', vol. ii. (Paris, 1891).

 METEORITE, a mass of mineral matter which has reached the earth’s surface from outer space. Observation teaches that the fall of a meteorite is often preceded by the flight of a fireball (see ) through the sky, and by one or more loud detonations. It was inferred by Chladni (1794) that the fireball and the detonations result from the quick passage of the meteorite through the earth’s atmosphere.

The fall of stones from the sky, though not credited by scientific men till the end of the 18th century, had been again and again placed on record. One of the most famous of meteorites fell in Phrygia and was worshipped there for many generations under the name of Cybele, the mother of the gods. After an oracle had declared that possession of the stone would secure to the Romans a continual increase of prosperity, it was demanded by them from King Attalus about the year 204, and taken with great ceremony to Rome. It is described by the historian as “a black stone, in the figure of a cone, circular below and ending in an apex above.” Plutarch relates the fall of a stone in Thrace about 470, during the time of Pindar, and according to Pliny the stone was still preserved in his day, 500 years afterwards. Both Diana of the Ephesians “which fell down from Jupiter,” and the image of Venus at Cyprus, appear to have been conical or pyramidal stones. One of the holiest relics of the Moslems is preserved at Mecca, built into a corner of the Kaaba; its history goes back far beyond the 7th century; the description of it given to Dr Partsch suggests that the stone had fallen from the sky. The oldest existing meteorite of which the fall is known to have been observed is that which fell at Ensisheim in Elsass on the 10th of November 1492. It was seen to strike the ground and was immediately dug out; it had penetrated to a depth of 5 ft. and was found to weigh 260 ℔. It was long suspended by a chain from the roof of the parish church, and is now kept in the Rathhaus of the town.

It was not till scientific men gave credence to the reports of the fall of heavy bodies from the sky that steps were taken for the formation of meteorite collections. The British Museum (Natural History) at South Kensington now contains specimens belonging to 566 distinct falls; of these falls 325 have been actually observed; the remaining specimens are inferred to have come from outer space, because their characters are similar to those of the masses which have been seen to fall. Of these meteorites the following twelve have fallen within the British Isles:—

Meteoritic falls are independent of thunderstorms and all other terrestrial circumstances; they occur at all hours of the day and night, and at all seasons of the year; they favour no particular latitudes. The number of stones which reach the ground from one fireball is very variable. In each of the two Yorkshire falls only one stone was found; the Guernsey County meteor yielded 30; at Toulouse, as many as 350 are estimated to have fallen; at Hessle, over 500; at Knyahinya, more than 1000; at L’Aigle, from 1000 to 2000; at both Pultusk and Mocs no fewer than 100,000 are estimated to have reached the earth’s surface. The largest single mass seen to fall is one of those which came down at Knyahinya, Hungary, in 1866, and weighed 547 ℔; but far larger masses, inferred from their characters to be meteorites, have been met with. The larger of the Cranbourne masses, now in the British Museum (Natural History), before rusting weighed tons; the largest of the masses brought by Lieut. Peary from western Greenland weighs tons. A mass found at Bacubirito in Mexico is 13 ft. long, 6 ft. wide and 5 ft. thick, and is estimated to weigh 50 tons.

From observations of the path and time of flight of the luminous meteor it is calculated that meteorites enter the earth’s atmosphere with absolute velocities ranging from 10 to 45 m. a second; but the speed of a meteorite after the whole of the resisting atmosphere has been traversed is extremely small and comparable with that of an ordinary falling body. According to Professor A. S. Herschel’s experiments, the meteorite which fell at Middlesbrough must have struck the ground with a velocity of only 412 ft. a second. In the case of the Hessle fall, several stones fell on the ice, which was only a few inches thick, and rebounded without breaking the ice or being broken themselves. The depth to which a meteorite penetrates depends on the speed, form, weight and density of the meteorite and on the nature of the ground. At Stannern a meteoric stone weighing 2 ℔ entered to a depth of only 4 in.; the large Knyahinya stone already mentioned made a hole 11 ft. deep.

The area of the earth’s surface occupied by towns and villages being comparatively small, the probability of a shower of stones falling within a town is extremely minute; the likelihood of a living creature being struck is still more remote. The first Yorkshire stone, that of Wold Cottage, struck the ground only 10 yds. from a labourer; the second, that of Middlesbrough, fell on the railroad only 40 yds. away from some platelayers at