MODE OF STRIKING. 



659 



strikes downwards, the inducing electricity in the cloud 



having struck in another direction, another tree for instance. 



One theory of the action of lightning, that of F. Cohn, of 



Fig. 291. Elm tree struck by li 



ept., 1897. 



Breslau, is that when lightning strikes a tree the wet cambium- 

 zone conducts the electrical discharge, and the contained 



u u 2 



