116 M. Ch. Martins on Trees Cleft by the 



The cleft trees produced by the direct action of the elec- 

 trical cloud mark out to us its line of passage above the 

 ground ; they always occupy the centre of the ravaged zone. 

 On the plateau of Malaunay, its total breadth was 220 

 metres ; in the centre they occupied a width of 89 metres. 



The cleavage presents different characters in different 

 trees. It is in oaks that it is most perfect ; the tree is divided 

 in laths which, towards the interior, are often not larger than 

 small flexible baguettes, or even common matches. The di- 

 rection of the cleavage always corresponds to that of the me- 

 dullary rays ; the tree being always broken across towards the 

 middle of the length of the cleavage, the baguettes which can 

 be detached are in general only the half of their entire length. 

 1 have separated two from the upper broken part of an oak 

 which are, the one 2'" -50, the other 2™-27 in length. The first 

 measured eight, the second five millimetres on the side. 



In beech-trees, the cleavage is coarser than in oaks ; we 

 rarely observe matches ; they are laths always two or three 

 centimetres broad, but often very long. It was in a large 

 beech 0'"-38 diameter at the base, that I observed the longest 

 cleavage ; it began at the surface of the ground, and rose 

 upwards to 7™"50 ; the tree was broken in the middle of this 

 length. Beeches were likewise the only trees, some of which, 

 four in number, remained standing after having been cleft 

 from the surface of the ground for a third or fourth of their 

 circumference, up to a height of from two to five metres. 

 These trees in every respect resembled trees struck with 

 lightning. 



The cleavage of poplars differs much from that of the trees 

 we have mentioned ; instead of being parallel, the planes of 

 cleavage are perpendicular to the rays of the tree. The 

 greatest breadth of the laths is in the direction of the layers 

 of white wood, which are separated from each other and dis- 

 jointed. Sometimes even the wood may be drawn out from 

 the white wood, as we withdraw the piston from a pump. 



In the valley of Montville, no resinous tree (pines, firs, 

 larches) was cleft. I counted twenty of them more or less 

 injured, but none were cleft, although they were in the direct 

 passage of the storm, and surrounded with others whose 



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