Chapter 7 THE EFFECTS OF LIGHTNING ON TREES AND PLANTS

Nearly two thousand years ago, Pliny wrote, "As regards products of the earth, lightning never strikes the bay tree." And this is why the Roman emperors, in fear always of the fire of heaven, crowned themselves with laurels. This belief was almost universal in ancient times, and survived for many centuries.

But every new century has proclaimed the immunity from lightning of some one member of the vegetable world, though impartial research has now established the fact that there is no such absolute privilege. If certain trees are rarely struck, that is, perhaps, due less to its species than to its size, its hygrometrical condition, and to other influences which it is still difficult to specify; for lightning, as we have seen, has capricious habits which we have not yet succeeded in explaining.

Thus the bay tree has lost its proud position in this respect, and has had to take its place amongst the ordinary run of trees, subject to the unjust anger of Jupiter. Many bay trees of some size have been seen to fall victims to the electric fluid.

The fig tree, the mulberry tree, and the peach tree have also been reputed to enjoy safety, but this also is not the case. There is an instance on record of a fig tree being struck by lightning and completely withered, and another of a mulberry-tree, eighty years old, being partly destroyed.

In our own days, the beech is believed to go uninjured. In the State of Tennessee, in the United States, the opinion is so deeply rooted that beech tree plantations are often resorted to as a refuge in times of storm. But it would be a mistake to place too much trust in them. There are records of beech trees being struck by lightning and destroyed, just like bay trees, fig trees, and the rest.

In 1835, an old beech tree was struck in the forest of Villers-Cotterets. This venerable patriarch was more than three hundred years old. Of its upper branches, which were wide and strong, four of the finest were destroyed; a fifth, stripped of its bark to a great extent, was not torn off the trunk. The trunk was split where the other four branches were torn from it. The interior of it was blackened and slightly carbonized.

On July 15, 1868, at Chéfresne, canton de Percy (Manche), an oak and an ash were struck by lightning within five minutes of each other.

On August 10, 1886, at Haute-Croix, in Brabant, an ash was struck and destroyed. On August 23, in the same year, an ash was struck also at Namur.

The box tree and the Virginian creeper used to be regarded as safeguards against lightning. The same virtue was attributed to the house-leek, a thick herbaceous plant, which grows usually upon walls and roofs, and which the Germans call Donnerblatt or Donnerbarb, Thunder-leaf or Thunder-beard.

According to some authors, again, lightning never strikes resinous trees, such as pines or firs. But this also is disproved by the facts, especially in regard to firs.

Among the many particulars I have collected of recent years, is the following list of sixty-five different kinds of trees, with the record of the number of times each species has been struck by lightning within a given period:-

54 oaks.

24 poplars.

14 elms.

11 walnut trees.

10 firs.

7 willows.

6 pine trees.

6 ash trees.

6 beech trees.

4 pear trees.

4 cherry trees.

4 chestnut trees.

3 catalpas.

2 lime trees.

2 apple trees.

1 mountain ash.

1 mulberry tree.

1 alder.

1 laburnum.

1 acacia.

1 pseudo-acacia.

1 fig tree.

1 orange tree

1 olive tree.

0 birch.

0 maple.

Height obviously accounts for a good deal. It is incontestable that, in the case of a clump of trees standing in the middle of a plain, lightning will in most cases pick out the tallest. But this is not an absolute rule. The isolation of trees, their qualities as conductors, the degree of moisture in the soil in which they are rooted, their distance from the storm clouds, the character of their foliage and of their roots-all these things are important factors.

Numerous experiments have been made with a view to ascertaining the amount of resistance offered to the electric spark by different kinds of wood. Similar pieces of beech and oak have been exposed lengthwise to the electric spark given out by one of Holtz's machines, with the result that the oak wood was pierced by the electric fluid after one or two revolutions of the machine, whereas for the beech wood a dozen or twenty were needed. Black poplar wood and willow offer a moderate resistance: a few revolutions suffice to penetrate them.

In all instances the susceptibility of the wood depends on the sap. It has been proved by analysis that the woods which contain starch with but little oil, such as the oak, poplar, willow, maple, elm, and ash, offer much less resistance to the electric current than those trees which are richer in fatty matter, as the beech tree, walnut tree, lime tree, birch tree, and so on.

These conclusions are corroborated by the case of the pine tree, the wood of which has a great quantity of oil in winter, but in summer lacks it as much as those trees which contain more starch.

Experiments have proved that in summer this wood is quite as likely to serve as a conductor as the oak; while in winter its resistance to the electric spark equals that of the beech and other trees which are rarely struck by lightning. Decayed trees are excellent conductors of electricity; those in full vigour being much more rarely struck.

In any case, it has been proved that the effects of lightning are particularly severe in the vegetable world. It has been pointed out elsewhere in this little book to what dangers those persons are exposed who take shelter beneath the trees during a thunderstorm; there are innumerable examples of the imprudence of taking refuge from the rain under thick foliage, people having been killed by a fireball-for lightning does not always take the trouble to make a selection, sparing neither the protector nor the protected.

We shall give some more instances, chosen from a considerable number of similar observations.

In 1888, ten reapers, surprised by drops of rain and distant rumbling of thunder, left their work and took refuge beneath a big walnut tree. But one of them having questioned the security of this retreat, all immediately fled in the direction of a neighbouring wood, except one young girl of fourteen years. Several who returned to advise her to follow them, saw her smilingly throw her arms round the trunk of the tree, and almost at once fall backwards, her arms extended. She was dead.

On the 22nd of August in the same year, four labourers, returning from work, were overtaken by a thunderstorm. Three of them stopped under an elm, the fourth prudently continued on his way. Well it was for him. Several minutes later, the lightning struck the tree, killing two of the labourers outright, and grievously wounding the third. The latter was found almost completely naked; his garments, burnt and tattered, were scattered round him. When he came to himself, he was in such a violent delirium that it was necessary for several men to bring the unfortunate victim to his home, where he died shortly afterwards in the most horrible agony.

About six o'clock, on the 23rd of June, seven men employed on the farm of Puy-Crouel, were working in a field of beet-root. Overcome with the heat, they went into the shade of a walnut tree. All at once, a flash of lightning illumined the sky; the seven workmen were thrown down, one of them being hurled several yards away. Three of them were able to get up and go to the farm, the others were severely burnt, and half asphyxiated. One of the victims had his back skinned the whole length of the vertebral column; the other had his face scratched, as if torn by fingernails. All had lost their memory. The walnut tree under which they had sheltered was cleft from top to bottom.

Here is another example no less terrible-

Seven children, belonging to Ahrens, were caught in a thunderstorm as they were coming home from the fields, and took shelter under a tree. The lightning killed the seven little people.

Another time, four young men taking refuge under an oak, were struck and thrown down. One of them was killed instantly, his companions were cruelly injured.

On the 10th of July, in Belgium, a woman gathering cherries was killed on a tree which attracted the fluid. A young man standing beneath it was paralyzed.

We might multiply these tragic tales; each year a number of similar cases happen. The imprudence of human beings is truly incorrigible!

Everybody, however feeble his instinct of self-preservation, should flee the vicinity of trees during a thunderstorm, and allow himself to be drenched on the road, rather than offer his life as a too generous burnt-offering to the lightning, for the oak's robust trunk, or that of the poplar, elegantly plumed with its graceful foliage, may be the altar on which the sacrifices in honour of Jupiter are made.

The wood of trees is not so good a conductor of electricity as the human body. For this reason, a person leaning against a tree receives the full discharge; at times the tree is splintered, because it did not serve as a perfect conductor.

Yet the conductive power of certain species is so remarkable, that the neighbourhood of particular trees may be regarded as a protection against lightning (this, however, without coming in contact with them!).

The tips of the branches pointing towards the clouds, and the moisture they receive, undoubtedly influence the electricity of the atmosphere; and, moreover, by means of these graceful branches, an inaudible but continual exchange is effected between the electricity of the earth and sky, thus holding the balance between two opposite charges.

Colladon asserts that poplars planted near houses may, in favourable conditions, act as lightning conductors, on account of their height and powers of conducting. He adds that it is necessary to take other circumstances regarding the situation of the dwelling into account, which are not always easy to define. Their protection of the neighbourhood is not constantly the same. For it to be effectual, the foliage should be very low, and they should be at least two metres distant from the roof and walls. Their roots, too, should be in a damp soil, and metal should not enter largely into the construction of the neighbouring houses. In these conditions, poplars may fulfil the useful functions of lightning conductors.

At times, during a storm, several trees are struck by the same flash. For instance, on May 23, 1886, in Belgium, three poplars were blasted by a single thunderbolt.

On the other hand, trees planted in lines are sometimes struck alternately. A case occurred where the lightning seemed to have taken aim and touched all the odd numbers in a row without striking the others.

Certain plantations act on the fluid with an extraordinary intensity.

At Lovenjoul, in Belgium, a wood of undergrowth and big trees, planted in marshy ground, seems to possess this singular privilege, and the agriculturists of the country declare that no storm ever passes their way without lightning falling there. In the middle of this wood one can count seven oaks, near to one another, struck by it. Not far off, a huge ash, and a little farther away two poplars, likewise blasted.

All the trees have not been struck in the same way; some are scorched or stripped of their leaves; the others have their trunks perforated, or split in different parts. Usually trees are cleft from top to bottom; in some cases the furrow is horizontal or perpendicular in the direction of the branches.

Pieces of bark or of wood are sometimes torn off lengthwise, and only adhere to the trunk in strips here and there. But that does not prove conclusively that the lightning struck upwards from the ground; it may have rebounded (?) after striking from above.

Certain effects, however, can only be explained by an ascending movement of the fluid. The following cases for example:-

"During the summer of 1787, two men were sheltering under a tree at Tancon, Beaujolais, when they were struck by lightning. One of them was killed on the spot, the other felt no ill effects other than momentary suffocation. Their horses were caught up to the top of the tree. An iron ring which bound the wooden shoe belonging to one of the men, was found hanging from a high branch of the same tree. Now, at a little distance, there was a tree which had also suffered greatly by the passage of the electric fluid. In the soil at its base a round hole was to be seen, shaped like a funnel. Directly above it the bark had been loosened and slit into slender thongs. As for the tree beneath which the men had sheltered, it also had half its bark off, and long splinters were to be seen hanging only by the upper parts. On one side of the tree the leaves were withered, on the other they were still quite green."

In this most remarkable instance the lightning had come out of the ground.

In the cleft of a willow tree blasted by lightning its roots were found.

Besides, the soil is often undulating, and thrown up around trees which have been struck.

Vegetables do not always succumb, any more than men, to these attacks. They may be lightly struck in a vital part, in which case they recover from their wounds. Very often they are merely stripped of their natural garments, in other words, of their bark and foliage. This is one of those superficial injuries to which they are most subject.

The following is an example of this kind of fulguration:-

On July 16, 1708, two oaks were struck at Brampton. The larger measured about ten feet around the base. They were both split asunder, and the bark peeled off from the summit to the soil, a length of twenty-eight feet. Completely detached from the trunk, it hung in long strips from the top.

Boussingault witnessed the destruction by lightning of a wild pear tree at Lamperlasch, near Beekelleronn. At the moment of the explosion an enormous column of vapour arose, like smoke coming out of a chimney when fresh coal has been put on the fire. The lightning flashed in all directions, great branches gave way, and when the vapour cleared off, there stood the pear tree, its trunk a dazzling white: the lightning had taken the bark completely off. Sometimes the bark is only partially stripped off one side, or left on, in more or less regular bands, either on the trunk or on the branches.

During a violent storm at Juvisy, on May 18, 1897, an elm five hundred metres distant from the Observatory was struck by lightning, which took the bark off lengthwise in a strip, four centimetres wide and five centimetres deep. This band of bark was cut clean off. There was no trace of burning.

Sometimes only the mosses and lichens are whisked off the sides of the trees, which escape with light scratches. Two great oaks which had been struck by fireballs, only bore traces of two punctures which might have been made by small shot.

Moreover, it is not uncommon to see the bark riddled with a multitude of little holes, like those made by worms.

Two men were struck by lightning near Casal Maggiore on August 15, 1791, beneath an elm tree. One of them had his elbow on the tree at the moment, and amongst other injuries were a number of little holes in the arm. There was a twist in the tree at the part where the elbow rested, and a hole penetrated the centre of it to the core of the wood. The surrounding bark looked as if it had been mite-eaten. Several scars started from this point and ascended almost perpendicularly towards the top of the trunk. There was no damage done to the branches.

Lightning cut through a chestnut tree, five metres high, on the roadside at Foulain (Haute-Marne), burning several leaves, then struck some water-pipes at a depth of a metre and a half, and finally passed into the dike through two holes a metre deep by a decimetre in diameter.

The bark is often reduced to thin splinters scattered on the soil, or hanging from the neighbouring trees, or even thrown to a considerable distance.

On June 25, a fireball fell near Jare (Landes) on a pine tree, which it shivered into a myriad slender strips, about 2 metres long, many of which were caught on the branches of pines within a distance of 15 metres. Only a stump, 2? metres in height, remained standing. At the same time three other pines, which stood 18 and 25 metres away from the first, were destroyed. The bark had been stripped off each, but only as far as the incision made for extracting the resin.

Furrows, of varying width, and running in different directions, may at times be seen on trees, some short, others reaching to the top of the tree, and occasionally to the roots. These marks show the passing of the lightning.

Sir John Clark has seen a huge oak in Cumberland, at least 60 feet high and 4 feet in diameter, from which the lightning had stripped a piece of bark, about 10 centimetres wide and 5 centimetres thick, the whole length of the trunk in a straight line.

The furrow is not always single, it may be double, and either stretch in two parallel lines or diverge.

The Chevalier de Louville observed in the park of the castle at Nevers, a tree struck at the top of the trunk by lightning which, dividing in three shafts, hollowed three furrows that might have been made by three rifle shots fired towards the roots. These three furrows followed the irregularities of the trunk, always slipping, gliding between the wood and the bark, and curiously enough the former was not burnt.

But these bands are not invariably straight either; in the above example they followed the caprices of the vegetable body. They are to be found oblique in certain cases, but more often they surround the trunk in long spirals of varying width, showing that the lightning clasped the tree in the form of a serpent of fire.

Here is an example:-

During a violent storm on July 17, 1895, a poplar was blasted on the road through the forest of Moladier, 160 metres north-west of the castle of Valliere. The tree was 25 metres high, and in full leaf from base to summit; it was struck halfway up by the discharge, and a spiral furrow 10 centimetres wide twisted round the trunk to the ground.

I noted a similar case, August 25, 1901.

Lightning struck one of the highest trees in the park at Juvisy, a magnificent ash, stripping off and destroying the bark where the electric fluid curved round and round down the full length of the trunk, which was shattered by the meteor a few metres above the roots. Enormous fragments lay all round the trunk, some hurled to such a distance that it was obvious the explosive force of the phenomenon must have been of extraordinary violence.

I was able to trace the course of the lightning to the foot of the tree, along its roots to a great depth, by a black furrow.

The tree is not dead. The ivy which clung to it is dead.

The vast and splendid forest of Saint Germain often witnesses the presence of the lightning, and the magnificent trees which adorn and beautify this charming and celebrated place are, unfortunately, too often the victims of these inopportune visitations.

Lightning has no respect for old memories. It demolished with a single flash a superb giant whose long branches, laden with perfumed leaves, had given shade to many generations. The splendid tree, which had survived the severity of several centuries, fell beneath the arrow of the pernicious fluid. Such was the fate of an oak near l'Etoile du Grand-Veneur. Struck on the top, its upper branches were violently torn off.... A spiral furrow beginning at the top ended within a metre of the ground. But, wonderful to relate, the whole mass of the tree appeared to have been twisted mightily by a force which worked with so much power that the tree could never regain its original position. The fibre, instead of growing vertically, followed the furrow made by the lightning, and became twisted like a corkscrew. There exist certain singular trees, the fibre of which grows in spiral fashion, and is called twisted wood by carpenters and cabinet-makers. Pines and firs in mountainous countries are fairly often affected in this curious fashion. One can no more account for it than one can define the cause of the curved form of some flashes of lightning. One does not know exactly if they should be attributed to their following the direction taken by the fibre, or whether, on the contrary, the tree had been struck in its infancy by a spiral flash, and, submitting to that influence, continued to grow up corkscrew fashion.

It is most probable that the fall of the thunder-ball on the trees in this manner is governed by the laws of electricity. We may even note casually that traces of similar spirals have been remarked on objects as well as on the dead bodies of those struck by lightning, thus preserving the ceraunic likeness of the mortal blow.

Other observers, besides, have declared that they saw distinctly the spiral lightning flash through the atmosphere. But these observations would need to be confirmed by photographs of indisputable accuracy. In these circumstances, as in many others, the dark room is worth a hundred human eyes!

In some cases the curved furrow turns several times. For instance, in May, 1850, Grebel saw an alder nearly twenty metres high struck by lightning on the right bank of the Elster below Zeitz. On the lower part of its trunk were two spiral bands which had carried away bark and sap-wood, leaving no trace of combustion.

The depth and width of the twist are very variable; at times the furrow is deeper in the veined parts than at the edges; again it reaches the core.

Two oaks were struck in June, 1742, in the park at Thornden. One was marked with a spiral for a length of forty feet to within a little distance of the ground. The band was five inches wide, but became narrower as it descended, and was finally no more than two inches wide. The wood was incised and even torn in places, but the branches were not hurt. The rest of the bark seemed to have been riddled by small shot.

All the injuries of which we have spoken (excoriation, stripping off the bark, furrows), are not necessarily mortal. But there are other more serious wounds from which the tree rarely recovers. We allude to deep fissures and breaks produced by lightning. When the fracture touches only a portion of the topmost part of the tree, the result of the accident is not necessarily fatal. But this is not always so.

On May 14, 1865, a poplar was split in two by lightning at Montigny-sur-Loing. One half to the full height continued standing. The other half was chopped up in small fragments and thrown to a distance of a hundred metres. These pieces, which were brought to me by M. Fouché, are so dried up and fibrous that they might be taken for hemp instead of wood.

In the majority of these cases the tree is split from top to bottom.

On July 5, 1884, in Belgium, a poplar, the biggest of a group of trees of the same species, was struck and split down its full length.

In the month of August, 1853, on the side of the road from Ville-d'Avray to Versailles, a poplar of about twenty years old was cleft from the topmost bough to its roots; one half remained in its place, the other fell on the road. A black line, about a millimetre wide, ran down the centre of the tree.

Sometimes the tree is divided into several parts by vertical fissures. For example, in 1827, near Vicence, a pear tree, three feet in diameter, was split into four parts, from the top down.

How often one has remarked great tree trunks in the forests, decayed and desolate, standing sadly, like poor headless bodies? Very often lightning has been the executioner of these trees.

In the month of May, 1867, in the forest of Fontainebleau, a magnificent oak, about two metres in circumference, was completely decapitated by lightning; its branches fell on the ground. The part of the trunk left standing was barked to the roots and splintered into fragments of varying sizes. They were scattered on the ground or hung from the branches of the surrounding trees. Several pieces of considerable size were hurled more than thirty metres away, much to the injury of the bark of the trees which they struck.

In numerous cases, the tree struck by lightning is broken in several places, and fragments of it thrown far and wide.

On July 2, 1871, at the farm of Etiefs, near Rouvres, canton of Auberive (Haute-Marne), lightning struck an Italian poplar, sixty years old, thirty metres high, and three metres round at a height of one metre from the ground, splintering off enough wood to make a heap sixty-five centimetres round, and fifty centimetres high.

An ash was struck by lightning on July 17, 1895, on the road to Clermont. This tree, ten metres high, was broken at a point 3? metres from the ground, and the crown, still hanging by a shred from the trunk, lay on the embankment. The violence of the explosion threw pieces thirty centimetres wide and 3? metres in length, into a field from twenty-five to thirty metres off.

On July 4, 1884, in Belgium, a willow was reduced to a heap of atoms on the ground. In March, 1818, at Plymouth, a fir more than a hundred feet high and forty feet in circumference, the admiration of the countryside, disappeared, literally shattered into bits. Some fragments were thrown two hundred and fifty metres away.

One of the most curious effects of lightning is to divide the interior of the tree into concentric layers, fitting them perfectly one into the other, but at the same time separating them with extraordinary precision.

Arbres roulés (thus are the trees called which are victims of this odd phenomenon), as a rule, do not show any injury on the outside. But the body, dissected by the electric fluid, soon succumbs.

An oak, twenty-five metres high, having been struck on August 25, 1818, was opened to be examined carefully, and it was stated that the concentric layers were as detached from one another as the tubes of an opera-glass.

The fireball sometimes hollows a canal through the centre of the trees from the top to the bottom, the sides of which are burnt black. The following is a curious example:-

In June, 1823, at Moisselles, lightning fell upon a great elm, and striking against an enormous knob, rebounded on to a neighbouring elm half its own height, pierced it through and through, shivering it to tatters; the trunk was burst open to the roots, it looked as if it had been bored through from one end to the other by a red-hot bullet that blackened and charred it.

Does it not seem as if the lightning plays with the lives of the trees as with man? It threatens, changes, apparently spares, returns to the charge and finally annihilates. And this sport is accompanied, at times, by inconceivable effects.

But records are still more eloquent than reflections: Nature, in her own mute speech, tells us of a thousand marvels.

Is not the following phenomenon enough to make lightning more mysterious in its fantastic and varied mode of action?

On the 19th of April, lightning struck an oak in the forest of Vibraye (Sarthe), cut this tree, measuring a metre and a half in circumference, at two-thirds of its height, pulverized the lower parts, strewed the shreds over a circuit of fifty metres, and planted the upper part exactly on the spot from which the trunk had been snatched, with all the rapidity of a flash.

Moreover, the annual concentric circles were separated by the sudden drying up of the sap so effectually, that, the strips only remained welded together where the knots made too great an obstacle to their separation.

How was the lightning able to plant in the earth, with such inconceivable rapidity, the top of the tree where the roots had been? This is something which no one can explain. It alone is capable of creating such situations.

But it has done better still! Two years later, in 1868, it took the opportunity of playing a good trick on two trees of different species, an English oak and a forest pine, which, without race jealousy, fraternized in the forest of Pont-de-Bussière (Haute-Vienne). These two trees were about ten yards apart, and were simultaneously hit by the explosive matter, and in the twinkling of an eye, their leaves were changed. The pine needles found themselves on the oak, and the leaves of the oak went to brighten the austerity of the pine with their delicate verdure. There was nothing commonplace about the metamorphosis. Accordingly all the inhabitants went in crowds to the scene of this miracle to contemplate the unusual spectacle of a pine-oak and an oak-pine.

And the unexpected happened: both trees appeared to thrive very well in these new conditions: the pine continued to be agreeably adorned with its festival foliage, whilst the oak agreed perfectly with the sombre needles of the pine.

After such marvels, my readers will not be surprised to learn that lightning sometimes shatters the living wood, or decayed wood, into a thousand morsels without setting it on fire.

For instance, a bundle of faggots lying on the hearth has been reduced to atoms by lightning, without any trace of combustion being visible.

A fireball fell on a sheaf of barley in the open field without setting it on fire, and buried itself in the ground without doing other further damage.

In certain cases the electric fluid chars wood at varying depths: the blackened layer is often very slight; sometimes, on the contrary, combustion is complete.

As for the leaves, they are unhurt as a rule. When they are attacked they shrivel up; an autumnal shade takes the place of their charming green tints; they turn brown and dry up quickly.

One of the trees in the Champs-élysées having been struck, it was proved that all round it the ground was full of little holes. In two or three places the bark was raised from beneath; the leaves were yellow and shrivelled up as parchment would be by the fire; the upper part remained green. Everything seemed to prove that the lightning came out of the ground.

At other times the same effect may be observed on the leaves, when the trunk and roots are apparently uninjured. It is not unusual to see the tree instantly stripped of its leaves as if by some mysterious power.

The lightning acts also on the roots, as we have seen in the preceding examples. They have been seen uncovered where the ground was much disturbed, torn in strips, or cleft in more or less regular pieces.

We see that lightning does not make more ado about exhaling its baleful breath on the life of plants, than on animals and men. And moreover, that it often strikes these latter with sudden death without leaving a trace of its passing, just as sometimes it strikes the trees without leaving any exterior injury. Now and then life is not completely extinguished, and little by little the tree recovers its health. Often the vitality is not changed, one sees the tree which was struck bear fruit as before the catastrophe.

Has it not been asserted that lightning may exert a benign influence on vegetation?

This was the opinion of the ancients.

A propos of this, Pliny said, "That thunder is rarely heard in winter, and that the great fertility of the soil is due to the frequency of thunder and rain in spring; for the countries where it rains often and in good earnest during the spring, as in the island of Sicily, produce many and excellent fruits."

It has been proved in our times that the ancients were right in extolling rainwater as nourishment for the products of the earth, and science has discovered the cause to be the presence of great quantities of nitrogen and ammonia in the thunder-rain and in hail. Perhaps electricity has a similar effect.

In the neighbourhood of Castres, on April 13, 1781, an old poplar was stripped of its bark in several places. Now, shortly afterwards it burst into leaf, although the neighbouring poplars were much later than it.

The ravages caused in the fields by the electric meteor to forage and vegetables are sometimes considerable. This is especially so with grass when cut, to haycocks, ricks of straw, barley, etc. We have a collection of records of men or animals who, when leaning against haystacks, were struck.

As a rule the haystack is burnt; sometimes, however, the grass is simply scattered and thrown to a distance.

In 1888, a very curious occurrence was observed at Vayres (Haute-Vienne).

The lightning struck a field of potatoes at the village of Puytreuillard; some of the stalks were burnt to cinders; but most remarkable of all, the potatoes were done to a turn, just as if they had been cooked beneath hot ashes.

A belief which was very general in ancient times and derived without doubt from a recollection of the circumstances which were said to accompany the birth of Bacchus, gave the vine the privilege of protecting the neighbourhood from the fatal effects of lightning. But this again is only a legend. The following observation proves it:-

On July 10, 1884, at Chanvres (Yonne), fifty vine-stocks were frizzled up by lightning.

It used to be supposed, too, that the electric fluid held the lily in particular respect. But here is a note which shows us that the white flower is visited by the burning flashes. During a violent thunderstorm on June 25, 1881, at Montmorin (Haute-Garonne)--But let M. Larroque, who witnessed the curious phenomenon, describe it: "In a clump of lilies in my garden," says he, "I see the highest of them surrounded by a violet glimmer, which formed an aureola round the corolla. This glimmer lasted for eight or ten seconds. As soon as it disappeared, I went close to the lily, which, to my great surprise, I found had been deprived of its pollen, while the surrounding flowers were laden with it. So the electric fluid must have scattered or carried off the pollen."

When Jupiter thunders, he still seems to dominate our world, as in the days when the graceful legends of mythology flourished.

And not only does he work above ground, but, contrary to the belief of the ancients, his influence extends beneath the soil.

A great number of men were working in the mines at Himmelsfurth on July 5, 1755. They were, as often happens, working at various points along the vein of metal, and never dreaming of the events which might take place on the surface of the ground. All at once they were conscious of several very violent shocks, given in the oddest and most extravagant fashion. Some felt the shock in their backs, while their neighbours received them on their arms or legs. They might have been shaken by a mysterious invisible hand, stretching now up from below, now from above, now from the sides of the galleries. One of the miners found himself hurled against the wall, two others, whose backs were turned, almost came to blows, each believing that his mate had thumped him.

The real culprit was the thunder, of whom they might well demand an explanation of these strange proceedings.

Here is another example which bears out the foregoing:-

On the 25th of May, the watchman on guard at the pit mouth of one of the principal mines at Freyberg, perceived an electric glimmer run along the wire rope going to the bottom of the mines, and used by the miners to exchange signals with the men employed in working the lifts. Suddenly all the pits were brilliantly lit up. At the same moment the watchman saw a clear vivid flame shoot out at the other end of the chain. On this occasion the lightning behaved with due discretion, and shone through the mine without giving any one the slightest shock.

In vain the monster Tiberius, and the infamous Caligula, sought a subterranean refuge from lightning. Their impure consciences, laden with crimes, dreaded the chastisement of heaven. By fleeing from the lightning flash, they believed themselves saved from death. Lightning dogs our footsteps, and works even when the criminals believe themselves in safety. It is conceivable that the ancients should have dreaded it as an instrument of celestial justice.

Usually lightning strikes the ground with a vertical stroke, but at times obliquely, when it traces long, horizontal lines. Often the ground may be seen turned up at the foot of trees which have been struck, the sod is torn, and stones thrown to a great distance. Sometimes, too, an excavation may be seen in the ground near the object struck, of varying breadth and height. This opening may be like a funnel or hemispherical.

In a case observed on June 6, 1883, at C?te (Haute-Sa?ne), a circular hole, having a depth of 1·20 metres, has been seen in a dyke on the declivity of the road, below a coach which was not struck.

Occasionally the hole is but the beginning of a canal, hollowed rather deeply and perpendicularly in the ground, the sides of which serve as a sheath to the fulgurite. But before treating of fulgurite tubes, which constitute the most curious phenomena in the world connected with lightning, we shall discuss certain remarkable effects observed on the surface of the ground.

Falling on solid rocks, the electric spark can break them, cut them, or pierce them in one or more places. Often instead of spoiling or cutting off pieces of the stone, it covers the surface instantaneously with a vitreous coat, having blisters of various colours. This vitrification is often to be seen on mountains.

De Saussure found rocks of schistous amphiboles covered with vitreous bubbles, like those seen on tiles where struck by lightning. Humboldt made similar observations on porphyritic rocks at Névada de Toluca, in Mexico, and Ramond, at the Sanadoire rock in Puy-de-D?me.

In these cases, the spark, on reaching the surface, melts it more or less completely over a varying extent, and this fusion, worked upon by an extraordinary heat, produces a coat having a peculiar appearance, but in which microscopical analysis finds the elements of the body it covers.

Thus the vitreous layer deposited over chalk is of chalky origin; that covering granite is of the nature of granite, etc.

This does not apply to certain deposits found on rocks, and even on trees, which have been struck by lightning, and which are of very different origin.

Whilst the former is only the stone in a fused or vitrified condition, the latter is caused by the presence of foreign bodies, some fragments of which have been detached by the ray and travel with it. This transport of solid substances by lightning has often been observed. Here are two examples of this strange phenomenon:-

On July 28, 1885, at Luchon, on the Bigorre road a passer-by saw lightning fall twenty yards away from him. Recovered from the shock, he went out of curiosity to look at the result, and saw the wall at the edge of the road, the schistous and chalky rocks, even the trees themselves, coated over with layers of brown. It was certainly a case of the lightning having effected a deposit. This latter was very curious. Lines could be traced on it with the finger-nail, it fell to powder under slight pressure, became soft with gentle rubbing, caught fire from a candle, and then gave off a resinous odour with much smoke. What is this resinous matter? That is what no one yet can say.

In the month of July, 1885, on the day following a violent thunderstorm which had struck the telegraph-office in the station of Savigny-sur-Orge, I myself picked up a little black powder off the telegraph poles, which had been left by the lightning, and which had a sulphurous smell.

The production of this ponderable matter has often been attributed to bolides, but direct observation proves beyond a doubt that the electricity carries various solid substances found on earth after a storm.

Lightning is truly the most venerable of glass-makers. Long before the most remote peoples of antiquity appeared, whose glasswares encrusted with marvellous iridescent tones by the passing of the centuries, are unearthed by scientific excavations, and displayed in national collections; long before man could have learnt to make use of the resources of nature, lightning, burrowing in the sand, there fashioned tubes of glass that hold the hues of the opal, and are called fulgurites.

The ancients seem to have known of these fulgurite tubes, but we owe the first precise description and the first specimen of these extraordinary vitrifactions to Hermann, a pastor at Massel in Silesia. His fulgurite, found in 1711, is in the Dresden Museum.

Since this discovery, fulgurites have often been sought for and found. The tubes, contracted at one end, and ending in a point, are to be seen in sandy soils.

Their diameter varies from 1 to 90 millimetres, and the thickness of their sides from half to 24 millimetres. As to the length, it sometimes exceeds 6 metres. Vitrified inside, they are covered outside with grains of sand agglutinated and apparently rounded as if they had been subjected to a beginning of fusion. The colour depends on the nature of the sand in which they have been formed. Where the sand is ferruginous the fulgurite takes a yellowish hue, but if the sand is very clean, it is almost colourless or even white. As a rule, the fulgurites penetrate the ground vertically, Nevertheless, they have been found in an oblique position. At times, also, they are sinuous, twisted, or even zigzag if they have met with pebbles of considerable size.

It is not uncommon for the fulgurite tube to divide in two or three branches, each of which gives birth to little lateral branches of 2 or 3 centimetres long, and ending in points.

There are also solid fulgurites and foliated fulgurites. The former, no doubt, had a canal originally, which has been stopped up by matter in fusion. The latter, instead of being stretched out in cylindrical form, are composed of slender layers like the leaves of a book.

The scientific museum at the Observatory of Juvisy possesses a very curious fulgurite which was offered to me some years ago by M. Bernard d'Attanoux, and found by him in Sahara. It is not a tube ending in a point. The lightning penetrating the sand, vitrified it on its passage, and branched irregularly in three principal directions. One might say it was slag formed by the juxtaposition, irregular and crumpled, of three blades of vitrified sand, which would be pressed together by leaving a narrow opening to their central vertical axis. This fulgurite, which is extremely light, measures six centimetres in length. It was found in the sand of Grand-Erg, at a depth of several centimetres. It has been found possible to produce miniature fulgurites by means of our electrical machines. By adding ordinary salt to the sand, and directing a strong current into it, complete vitrification of a tube of several millimetres is obtained.

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