Trees Struck by Lightning 203 



common, and not unfrequently the dead branch is a large 

 one and projects far towards the circumference of the tree. 

 It is well known that lightning rarely strikes the very tops 

 of trees, but usually rushes to the bole lower down, guided by 

 some branch. We have but to suppose that broken and dead 

 wood, moistened as it usually is in rain, offers a more attrac- 

 tive point and better conduction than a leafy and living bough. 

 Apart from actual demonstration, this is highly probable. If 

 the facts were proven they would go far to explain the exces- 

 sive liability of the oak. 



The subject is, however, a complicated one, and very 

 probably no single explanation will suffice for all cases. 

 Experiments which are referred to by Flammarion appear 

 to have proved that oak wood is much more easily penetrated 

 by the electric spark than is the wood of beech. In this sus- 

 ceptibility black poplar and willow share with oak, though in 

 a rather less degree. In what way this susceptibility would 

 influence the proneness to receive the lightning flash may 

 require some consideration. It may possibly be of importance 

 in reference to the splintering and killing of the tree as a 

 whole. We shall recur to the subject and invite our readers 

 to supply us with carefully observed facts. 



It is possible that in investigating the peculiarities in 

 different trees as explanatory of their liability to be struck by 

 lightning, too much attention has been given to the conduct- 

 ing power of the wood. So far from this being necessarily 

 an element of danger to the tree, it may be one of safety, 

 and at any rate it is only one amongst many contributing 

 influences which may modify the kind of damage done. 



It is to be remembered that during a thunderstorm the 

 earth and the clouds are in opposite states of electric tension, 

 and, so to speak, straining to get at each other. Although in 

 most instances the current passes downwards to the earth, it 

 no doubt sometimes passes upwards from the earth. Every 

 object on the earth's surface is at the moment charged with 

 electricity, each according to its storage capacity. Thus it 



