Thunder and Lightning Part 16

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 succ.u.mb, 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 fireb.a.l.l.s, 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 mult.i.tude 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 pa.s.sed 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 s.h.i.+vered 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, 2-1/2 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 pa.s.sing of the lightning.

Sir John Clark has seen a huge oak in c.u.mberland, 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 ma.s.s 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 fas.h.i.+on, and is called twisted wood by carpenters and cabinet-makers. Pines and firs in mountainous countries are fairly often affected in this curious fas.h.i.+on. 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 fas.h.i.+on.

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 circ.u.mstances, 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. Fouche, 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 circ.u.mference, 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 3-1/5 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 3-1/2 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 circ.u.mference, 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 roules_ (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 succ.u.mbs.

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-gla.s.s.

The fireball sometimes hollows a ca.n.a.l 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:--