Part 3 (1/2)
A sailor tells us that once when he was out at sea, more than 100 kilometres from Lima, he saw a number of bright flashes, without any thunder, to the east and north-east of the horizon. The weather was perfect, and the sky absolutely serene. Now we know that storms, and the electric phenomena which they produce, are unknown upon that coast; but this immunity does not extend for more than 100 kilometres to the interior of this country, so that this lightning which was observed at sea, 100 kilometres from the sh.o.r.e, must have taken place more than 200 kilometres away.
One of our correspondents, M. Soleyre of Constantine, sent us word, in 1899, of an interesting case of lightning without thunder.
”In August,” he says, ”I noticed it in the valley of the Arve above Salambes; when I came back to Algiers I saw it again on September 16, and on October 19.
”It was not sheet lightning, but ordinary lightning concentrated in very thin lines. This lasted long, and was very near. Another thing, there was no hail. This is not very rare in Algiers.”
On September 1, 1901, I happened to be in Geneva at about 6 p.m. The weather was heavy but very fine. I noticed a good deal of lightning on the south-west of the horizon. It went on almost without interruption above the Savoy Alps. Each flash illuminated at the same time the ridge of the mountains and the fringed edge of the great sombre clouds lying low on the horizon. This lightning was silent; the noise of the thunder did not reach Geneva. The next day I learnt that a terrible storm had devastated the neighbourhood of Chambery and Aix-les-Bains.
Moreover, apart from storms, there have been other records of this lighting up of the sky being observed at great distances.
Thus, in 1803, a service of luminous communications was established on Mount Brocken in the Hartz Mountains in order to determine the differences of longitude. The combustion of 180 to 200 grammes of powder, burnt in the open air, for each of the signals, produced a light which was observed by astronomers stationed on Mount Kenlenberg, although they were 240 kilometres from Brocken, which is itself invisible from Kenlenberg.
On certain fete-days, July 14, for example, when the princ.i.p.al monuments in Paris are illuminated, at a distance of 20 and 30 kilometres we can see a sort of luminous vapour which floats above the town and reflects the lights of the boulevards, although the lights themselves are invisible from the point of observation.
Here is another example which any Parisian can verify: the captive balloon of the Aerodrome at Porte-Maillot, which soars some hundreds of yards above Paris during the spring and summer, as seen from the dark paths of the Bois de Boulogne, appears against the azure of the sky like a magnificent globe bathed in light, resembling an enormous moon. Well, this gentle, pale light is only the reflection of the lights of Paris which are invisible from the Bois de Boulogne.
The earth and all the planets which are dark in themselves, s.h.i.+ne in s.p.a.ce lighted up by the sun.
The silent lightning which flashes in the sky is only the reflection of a distant storm. Whether on account of the spherical shape of the earth or on account of the irregularities of the land, the clouds are invisible, but the effluvium which escapes from them can be seen at a great distance.
These poetic and ephemeral flames which glide through the sky, appeal to the imagination of the dreamer, and yet they are quite as terrible as the flashes which are accompanied by thunder. If the noise which accompanies these is not perceptible, it is because the sound of the thunder does not carry far, and has been lost in s.p.a.ce before reaching us.
It is the same with the silent lightning which gleams in a stormy sky.
This phenomenon is particularly frequent in the Antilles. Either the storm breaks too far from the observer, or the discharge has taken place between two beds of clouds, the lower of which intercepts the waves of sound without preventing the escape of the electric spark, and the thunder is not heard.
As a rule we imagine that lightning always descends, that it comes to us from the higher celestial regions to be lost in the common reservoir. But this is quite inaccurate. Lightning sometimes ascends.
Sometimes it descends and reascends. That is to say, after it reaches the ground, either there is no attraction there, or a stronger force draws it back to the aerial regions, and it flies back to the clouds whence it came.
As a rule we only fear the direct lightning. This is a great mistake.
There are many cases of lightning striking from a distance.
For example, at the end of May, 1866, an English coastguard was making his rounds on the coast of one of the Shetland Isles, when a flash of lightning pa.s.sed near him, striking a great rock. The unfortunate man was completely blinded, and plunged into darkness thus suddenly, he would inevitably have fallen down an abyss, if his companions, attracted by his cries, had not come to the rescue and taken him home.
Here is another case:--
On September 24, 1826, a terrible storm burst over Versailles, accompanied by a great deal of thunder and lightning. At the moment when the lightning struck Galli's farm, an old man who was in a street in Versailles, at a distance of two kilometres from the farm, suddenly felt a violent shock, accompanied by a feeling of oppression and giddiness and a semi-paralysis of the tongue and the whole of his left side. Next morning this had pa.s.sed away, but in the evening at the same time as the shock had occurred, he felt similar sensations of fainting, and it was the same to the end of the week. It would be well to remark here that at the moment of the accident, M. B---- happened to be near the wall of a house, not far from the metallic tube which conducted the rain-water into the level of the pavement.
The following phenomenon, to which we have already alluded, is no less curious:--
On July 22, 1868, at about 7 o'clock in the evening, at Gien-sur-Cure (Nievre), the thunder had been growling violently for some time, when all of a sudden the lightning struck a thatched house, which it set on fire. At the same time a woman who was in a house ten yards away, felt a shock, and saw the tiled floor rise beneath her. Her two sabots were broken on her feet, and a bottle of Holy Water with which she was blessing the house was broken in her hand, only the neck remained in her fingers. She herself suffered nothing but the shock. Nineteen of the tiles were flung in all directions.
Here is another very remarkable case of _ascending lightning_, published in the _Comptes Rendus_ of the Academie des Sciences:--
At Porto-Alegre, on June 9, 1870, at 2 a.m., during a violent storm, on the property of M. Laranja e Oliveira, at Brazil, a servant was entering the house; he was about ten yards away, when a flash of lightning illuminated it; at the same moment he felt a great tingling in the flesh of his feet, then in his legs, then all over his body, and finally in his head, on which the hair stood on end to such an extent that _he was obliged to hold his hat on_ in order to prevent its falling off. At the same time, a white flame burst from the ground about two yards in front of him, accompanied by a shower of sparks.
Terrified by such a phenomenon, which he attributed to souls from another world, he thought he was petrified to the spot; finally, he ran away. Anything metallic which he had about him at the time of this occurrence became magnetized. A key which was in his pocket remained magnetic for two days.
Thus, as well as the ordinary fulguration, in which the lightning (which we imagine descends from the clouds) acts directly on the body, and the lightning which strikes indirectly, there are other electric shocks which can be experienced by men and animals. Notable among these is the _striking from the earth_, commonly known as _choc de retour_, and which is in reality only an instance of the ascending current, or of lightning striking from a distance. We must also describe the striking _by a man who has been struck_.
The Abbe Richard, in his _Histoire de l'Air_, tells the following story:--