Part 16 (1/2)

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.