The inexplicable phenomenon was that at the precise moment when the lightning crossed the stable, a great quantity of incandescent stones fell before a neighbouring house. "Some of these fragments, of the size of nuts," wrote the Minister of Post and Telegraphs at the Academy, "are of a not very thick material, of a greyish-white, and easily broken by the fingers, giving forth a characteristic odour of sulphur. The others, which are smaller, are exactly like coke.
"It would perhaps be useful to say here, that during this storm the thunderclaps were not preceded by the ordinary muttering, they burst quickly like the discharge of musketry, and succeeded one another at short intervals. Hail fell in abundance, and the temperature was very low."
It is only by a semblance of disbelief that one can get the peasants to tell us the stories of what they pretend to have seen of the fall of aeroliths during storms. They have christened the uranoliths "thunder-stones."
These substances have evidently no relation to uranoliths, but they prove none the less that ponderable matter may accompany the fall of lightning.
Here are two more examples—
In the month of August, 1885, a storm burst over Sotteville (Seine-Inférieure); lightning furrowed the sky, the thunder muttered, and the rain fell in torrents. Suddenly, in the Rue Pierre Corneille, several small balls, about the size of a common pea, were seen to fall; these burned on touching the ground, sending out a little violet flame. People counted more than twenty, and one of the spectators, on putting her foot on one of them, produced a fresh flame. They left no trace on the ground.
On August 25, 1880, in Paris, during a rather violent storm, in broad daylight, M. A. Trécul, of the Institute, saw a very brilliant voluminous body, yellowish-white, and rather long in shape, being apparently 35 to 40 centimetres in length, by about 25 in width, with slightly conical ends.
This body was only visible for a few seconds; it seemed to disappear and re-enter a cloud, but in departing—and this is the chief point—it dropped a little substance, which fell vertically like a heavy body under the sole influence of gravity. It left a trail of light behind it, at the edges of which could be seen sparks, or rather red globules, because their light did not flash. Near the falling substance the luminous trail was almost vertical, while in the further part it was sinuous. The small substance divided in falling, and the light went out soon after, when it was on the point of reaching the tops of the houses. When it was disappearing, and at the moment of the division, no noise was heard, although the cloud was not far away.
This fact incontestably proves the presence of ponderable matter in clouds, which is not violently projected by an explosion in the bolis, nor accompanied by a noisy electric discharge.
We are still far from understanding the interesting problem of the formation and nature of ball lightning. Instead of denying it, men of science ought to study it, because it is certainly one of the most remarkable of the curiosities of atmospheric electricity.