Effects of Lightning on Wood. 109 



den transformation into a highly elastic vapour, of the water 

 commingled with the strata on which the foundations of a 

 dwelling-house repose, will be sufficient to uplift the entire 

 house, and transport it, as has been actually the case, to a con- 

 siderable distance. When the celebrated Watt for the first 

 time saw the enamelled hollow tubes, which lightning had pro- 

 duced in a mass of sand, he exclaimed '' See here an effect of 

 the elastic force of steam which the lightning has produced in 

 traversing the sand." At the same time, nothing appears to 

 me to indicate more clearly and directly the action of aqueous 

 vapour, than the singular tearing into shreds which wood un- 

 dergoes when it has been penetrated by lightning. 



LightniTig cleaves wood in the direction of its length into a number 

 of thin lathsy or into still smaller fragments, 



A flash of lightning struck the Abbey of St Medard de Sois- 

 sons in tlie year 1676, and the following is the description of 

 its effects, on some of the rafters of the roof, by an eye-witness : 

 " Some of them were found to the depth of three feet, divided 

 almost from top to bottom into the form of very thin laths ; 

 others of the same dimensions were divided into the form of 

 long and fine matches; and, finally, some were divided into 

 such delicate fibres that they almost resembled a worn-out 

 broom.*" Let us now proceed to green-wood, and we shall find 

 that the effects are analogous. On the 27th of June in the year 

 1756, the lightning struck at the Abbey of Val, near the island 

 Adam, a large isolated oak 52 feet high, and somewhat more 

 than four feet diameter at its base. The trunk was entirely 

 stripped of its bark. This bark was found dispersed in small 

 fragments all round the tree, to the distance of thirty and forty 

 paces. The trunk, till within about two yards of the ground, 

 was cleft longitudinally into portions almost as thin as laths. 

 The branches were still connected with the trunk, but they 

 too were deprived of every particle of bark, and had been 

 subjected to the most remarkable longitudinal slicing. The 

 trunk, branches, leaves, and bark, did not exhibit any trace 

 of comhustion, only they appeared completely dried up and 

 withered. 



