Miscellany.
Singular Effects of Lightning.—Sir David Brewster has published an account of the effects of lightning in Forfarshire, which is of much interest. In the summer of 1827, a hay-stack was struck by lightning. The stack was on fire, but before much of the hay was consumed the fire was extinguished by the farm servants. Upon examining the hay-stack, a circular passage was observed in the middle of it, as if it had been cut out with a sharp instrument. This circular passage extended to the bottom of the stack, and terminated in a hole in the ground. Captain Thomson, of Montrose, who had a farm in the neighborhood, examined the stack, and found in the hole a substance which he described as resembling lava. A portion of this substance was sent by Captain Thomson to Sir David's brother, Dr. Brewster, of Craig, who forwarded it to Sir David, with the preceding statement. The substance found in the hole was a mass of silex, obviously formed by the fusion of the silex in the hay. It had a highly greenish tinge, and contained burnt portions of the hay. Sir David presented the specimen to the Museum of St. Andrew's.
Ancient Glacier in the Pyrenees.—M. Charles Martens, who was present at the meeting of the British Association, read a paper on the ancient glacier of the Valley of Argelez. This glacier and its affluents descended from the crest of the Pyrenees, whose summits now reach an altitude varying from 6000 to 9000 feet. The roots of the glacier were in the cirques of Gavarnie, Troumouse, Pragnères, etc., and the glacier extended into the plain as far as the villages of Peyrouse, Loubajac, Ade, Juloz, and Arcisac-les-Angles. Along the valley, polished and striated rocks, scratched pebbles, glacial mud, moraines, and erratic boulders, are the proofs of its existence. At Argelez, the thickness of the glacier was about 2100 feet, and, at the opening of the valley at the foot of the Pic de Geer, near Lourdes, 1290 feet. Between Lourdes and the village of Ade, the railway runs across seven moraines; and the railway from Lourdes to Pau is cut, as far as the village of Peyrouse, through glacial deposits. The Lake of Lourdes is a glacial lake, barred by a moraine, and surrounded by numerous erratic boulders proceeding from the high Pyrenean mountains. Some of the boulders are of large dimensions: thus one of them, between the lake and the village of Poueyferré, is thirty feet in length, twenty-three feet in width, and eleven feet in height. This lake of Lourdes, surrounded by hills covered with briars, reminds one, in many respects, of the small lakes of Scotland.
A Burning Well.—While some artisans were engaged in making borings for an artesian well at Narbonne, France, the water rushed forth with great violence, and soon burst into flame. The flame, which arises from the combustion of carburetted hydrogen, is reddish and smoky, and does not emit a smell either of bitumen or sulphuretted hydrogen. The "sinking" for the spring was made on the left branch of the Aude, in a plain situate about two metres above the sea-level, and composed of alluvial mud. The alluvial mud extends to a depth of six metres; then follow tertiary limestones and marls, with the remains of marine shells. At the depth of seventy metres, the spring containing the inflammable gas was met with.
Comets and Meteors.—In a paper on this subject, laid before a late meeting of the Astronomical Society, Mr. G. J. Stony, Secretary to the Queen's University in Ireland, makes the following interesting observations, which tend to show, as Schiaparelli has already pointed out, that there is a very natural relationship between comets and meteors. If interstellar space, external to the solar system, be, as is most probable, peopled with innumerable meteoric bodies independent of one another, a comet while outside the solar system would in the lapse of ages collect a vast cluster of such meteorites within itself. Each meteorite which approached the comet would in general do so in a parabolic orbit; and, if it came near enough to pass through a part of the comet, this parabolic orbit would, by the resistance of the matter of the comet, be converted into an ellipse. The meteor would, therefore, return again and again, and on each occasion that it passed through the comet its orbit would be still further shortened, until at length it would fall in, and add one to whatever cluster had been brought together by the previous repetitions of this process. In this way a comet, while moving in outer space, beyond the reach of the many powerful disturbing influences which prevail within the solar system, would inevitably accumulate within itself just such a globular cluster of meteors as the November meteors must have been before they became associated with the solar system.