A tree which has been struck by lightning is naturally regarded by the savage as charged with a double or triple portion of fire; for has he not seen the mighty flash enter into the trunk with his own eyes? Hence perhaps we may explain some of the many superstitious beliefs concerning trees that have been struck by lightning. When the Thompson Indians of British Columbia wished to set fire to the houses of their enemies, they shot at them arrows which were either made from a tree that had been struck by lightning or had splinters of such wood attached to them. Wendish peasants of Saxony refuse to burn in their stoves the wood of trees that have been struck by lightning; they say that with such fuel the house would be burnt down. In like manner the Thonga of South Africa will not use such wood as fuel nor warm themselves at a fire which has been kindled with it. On the contrary, when lightning sets fire to a tree, the Winamwanga of Northern Rhodesia put out all the fires in the village and plaster the fireplaces afresh, while the head men convey the lightning-kindled fire to the chief, who prays over it. The chief then sends out the new fire to all his villages, and the villagers reward his messengers for the boon. This shows that they look upon fire kindled by lightning with reverence, and the reverence is intelligible, for they speak of thunder and lightning as God himself coming down to earth. Similarly the Maidu Indians of California believe that a Great Man created the world and all its inhabitants, and that lightning is nothing but the Great Man himself descending swiftly out of heaven and rending the trees with his flaming arms.

It is a plausible theory that the reverence which the ancient peoples of Europe paid to the oak, and the connexion which they traced between the tree and their sky-god, were derived from the much greater frequency with which the oak appears to be struck by lightning than any other tree of our European forests. This peculiarity of the tree has seemingly been established by a series of observations instituted within recent years by scientific enquirers who have no mythological theory to maintain. However we may explain it, whether by the easier passage of electricity through oak-wood than through any other timber, or in some other way, the fact itself may well have attracted the notice of our rude forefathers, who dwelt in the vast forests which then covered a large part of Europe; and they might naturally account for it in their simple religious way by supposing that the great sky-god, whom they worshipped and whose awful voice they heard in the roll of thunder, loved the oak above all the trees of the wood and often descended into it from the murky cloud in a flash of lightning, leaving a token of his presence or of his passage in the riven and blackened trunk and the blasted foliage. Such trees would thenceforth be encircled by a nimbus of glory as the visible seats of the thundering sky-god. Certain it is that, like some savages, both Greeks and Romans identified their great god of the sky and of the oak with the lightning flash which struck the ground; and they regularly enclosed such a stricken spot and treated it thereafter as sacred. It is not rash to suppose that the ancestors of the Celts and Germans in the forests of Central Europe paid a like respect for like reasons to a blasted oak.

This explanation of the Aryan reverence for the oak and of the association of the tree with the great god of the thunder and the sky, was suggested or implied long ago by Jacob Grimm, and has been in recent years powerfully reinforced by Mr. W. Warde Fowler. It appears to be simpler and more probable than the explanation which I formerly adopted, namely, that the oak was worshipped primarily for the many benefits which our rude forefathers derived from the tree, particularly for the fire which they drew by friction from its wood; and that the connexion of the oak with the sky was an after-thought based on the belief that the flash of lightning was nothing but the spark which the sky-god up aloft elicited by rubbing two pieces of oak-wood against each other, just as his savage worshipper kindled fire in the forest on earth.