Page:Popular Science Monthly Volume 37.djvu/384

370 In 1818 Dr. W. G. Reynolds, in offering a theory on meteorites, says: "Dr. Blagden considers electricity as the general cause of these phenomena; Dr. Gregory and others think they depend on highly inflammable matter, as phosphorus, phosphorated hydrogen, etc., being volatilized and congregated in the upper regions of the air. Dr. Halley ascribes them to a fortuitous concourse of atoms, which the earth meets in her annual track through the ecliptic; and Sir John Pringle seems to regard them as bodies of a celestial character, revolving around centers, and intended by the Creator for wise and beneficent purposes, perhaps to our atmosphere, to free it of noxious qualities, or supply such as are salutary." Dr. Reynolds then goes on to elaborate a most complicated theory in which solid substances on the earth are changed to vapor by the sun's heat; these, rising as gases, finally give up their heat by an explosion, and the particles, having no heat to keep them apart, rush together and come down as solids.

"While the minds of the scientific men of France were in this unsettled condition, there came a report that still another shower of stones had fallen, this time in their own country, and within easy reach of Paris. To settle the matter finally, if possible, the physicist Biot, member of the French Academy, was directed by the Minister of the Interior to inquire into the event upon the spot. After a careful examination of the stones and a comparison of the statements of the villagers, Biot was convinced that—

"1. On Tuesday, April 26, 1803, about 1, there was a violent explosion in the neighborhood of L'Aigle, in the department of Orne, lasting for five or six minutes; this was heard for a distance of seventy-five miles round.

"2. Some moments before the explosion at L'Aigle, a fire-ball in quick motion was seen from several of the adjoining towns, though not from L'Aigle itself.

"3. There was absolutely no doubt that on the same day many stones fell in the neighborhood of L'Aigle.

"Biot estimated the number of the stones at two or three thousand; they fell within an ellipse of which the larger axis was 6·2 miles, and the smaller 2·5 miles; and this inequality would indicate not a single explosion but a series of them. With the exception of a few little clouds of ordinary character, the sky was quite clear.

"The exhaustive report of Biot, and the conclusive nature of his proofs, compelled the whole of the scientific world to recognize the fall of stones on the earth from outer space as an undoubted fact."

The main difficulty in forming theories at the present time is