Tho earth having now fairly entered that portion of its orbit rouad the san during which it cornos in contact the first time this year with nieteoric showers, we may look during the next few evenings for displays in the heavens of fireworks on a magnificent scale. It is true that meteors appear in their. grandest aspect and in greatest number every thirty-throe years, but this law, as determined by observation of astronomers, is not unchangeablo. The phenomena occur to a greater or less exfcent twice every year, August and November. The origin of meteors was long without receiving a satisfactory explanation, that most generally accepted being that they were caused by the existence of inflammatory gasts in tho atrnosphere. The irnis faiius, no doubt, is produced in this way, for it has been found to chango its inotion by the slight current of air preeeding a person walking towal'd it. But the immense velocity of the meteors that appear in August and November, which is aboutequalto twice thnt of the earth in its orbit, or thirtysix miles in a second, and tbe great elevation at which they become visible, the average being sixty miles, indicate clearly that they are not of terrestrial but cosmical origin - that is, they originato from the interplanetery regions, innumerable fragments of fieavenly bodies that have been shattered to piecea traversing space, and, being brought within the sphere of the earth's attraction, precipítate themsolves upon its surface. Moving with the great velocity rnentioned through the higher regions of the air they become so intenseiy heated by friction that they ignite, or are at least rendered visible, and are either converted into vapor, or, when very large, explode and descend to the earth's surface as meteoric stones or aerolites. Prof. Thomson, of the British Association, says that they are " small bodies which come into the earth's atmosphere, and the instant they touch it their surfaces are heated bevond the point of fusión or even of volatilization, and the conseqnence is that they are speedily and completely burned down and reduced to impalpable oxides." The brilliancy and color of meteore are variable; some are as bright as Venus or Júpiter. About two-thirds are white, the remainder yellow, orange or green. The problem of their origin must be regarded as the same with that of tho a3teroids, revolving around the sun between the orbs of Mars and Júpiter, and of the planets themselves. Some astronomers consider their origin precisely the same as that of the comets, which may be regarded as only meteors of vastsize. The shower of 1799 was awful and sublime beyond description. It was witnessed by Humboldt at Cumana, in South Ameriea, and is thus described : "Toward the morning of the 13 th of November, 1799, we witnessed a most extraordinary scène of shooting meteors. Thousands f bolides and falling ' stars succeeded each other duriug the four hours. Their direction was very regularly from north to south, and from the beginning of the phencmenon there was not a space in the firmament equal in extent to tliree diameters of the moon which was not filied every instant with bolides or falling stars. All the meteors left luininous traces or phosphorescent bands behind them, which lasted seven or eight soeonds." The same phenomena was seen throughout nearly the whole of North America and South America and in soine parte of Europe. The most splendid display of shooting stars on record was that of Nov. 13, 1833, and is especiallyinteresting as having ser ved to point out the periodicity ia these phenomena. Over the northern portion of the American continent the spectacle was of the most imposing grandeur, and in many parts of tho country tho population worc terror-atricken at the awfulness of the scène. The slaves of the Southern States supposed the world was on fire, and filied the air with shrieks of horror and cries for mercy. The shower of 1866 was auticipated with great interest, and in New York and other places arrangementa were made to announce the occurrence during the night of Nov. 14 by ringing the bells from the fire towers. The display, however, was not witnessed in this country, but in England was quite brilliant, as many as 8,000 meteors being counted at the öreenwich Observatory. Another shower of less extent occurred in 1867, and a record has been kept at tho Naval Observatory, Washington, of the number of shooting luminous bodies that appeared in the months of August and November in oach year since.