The Museum Gazette 



may be that the storage capacity, rather than the conductivity 

 of different trees, is the main element in determining which 

 shall be struck. 



It is necessary also to take into account the forms of the 

 leaves and direction of the twigs. Pointed structures receive 

 and give off the electric current more easily than blunt ones. 

 Thus the erect stems of fir trees and the comparatively erect 

 twigs of the oak may be more efficient than the drooping ends 

 of the leaf-covered branches of the beech. 



Our domestic animals are much more easily killed by 

 lightning than human beings. This may be because the 

 points of their hairs attract the fluid. 



In all observations on the effect of lightning on trees, care 

 should be taken to record the time of year. If the accident 

 should happen in spring, when the sap is in full descent 

 between bark and bole (in the cambium layer), the current 

 would find its easiest path in that layer. It would by its heat 

 produce steam, and thus loosen the bark or perhaps blow it 

 completely off. In such case the bole might not be shattered, 

 but simply denuded. The denudation might not involve the 

 whole circumference, and then the tree might not be killed. 

 Late in the autumn there is somewhat more risk that the fluid 

 may pass down the wood itself, since the layer under the bark 

 would be less efficiently conductive. 



Probably the instances in which the current passes down 

 under the bark are far more numerous than those in which it 

 involves the wood itself. Yet we record for the most part 

 only the latter, for the damage done in the former is often not 

 at first conspicuous. It is in the after-growth of the tree 

 that furrows reveal the fact. 



The striking of trees by lightning is probably far more 

 common than is generally supposed. A little search in almost 

 any wood will discover trees which have been fluted by tearing 

 up their bark, whilst those which have been broken or shattered 

 are very rare. It is just possible that we have more than our 

 share of lightning-struck trees at Haslemere. The sandstone 



