262 Mr Charles Tomlinson on Lightning Figures. 
duces these tree-like impressions which have excited so much 
astonishment, and led to so much false description and wei 
during the last eighty or ninety years. 
M. Poey relates twenty-four cases of lightning impressions 
on the bodies of men and animals. Of these, eight are said 
to be impressions of trees or parts of trees; two of animals, 
viz., a bird and a cow; four of crosses; three of circles or 
impressions of coins carried about the person ; two of a horse- 
shoe; one of a nail; one of a metal comb; one of a number; 
one of the words of a sentence; and one of the back of an 
arm-chair. 
M. Poey would refer the production of these figures to pho- 
tography, in which lightning is the efficient agent instead od 
the sun. 
M. Baudin (Traité de Geographie Médicale) proposes a 
new term for the branch of science which is to include these 
figures, viz., Keraunography (from xegauvos, thunder). I do 
not think it necessary to seek for new laws to explain these 
effects, but I should not place the impressions of metal and 
other objects in the same class with the tree-like figures. 
The experiments of M. Fusinieri on the transference of 
metallic particles from one conductor to another’ are calculated 
to explain many of these cases; but details of this kind have 
already been included in the ordinary treatises on electricity. 
P.S.—Since this paper was read before the British Associa- 
tion, a case has come to my knowledge which confirms my 
theory—namely, that the tree-like impressions sometimes found 
on the bodies of men and animals struck by lightning are pro- 
duced by the figures which the lightning itself assumes in 
striking the earth. Conversing on this subject with Mr Charles 
Pooley of Weston-super-Mare, he informed me that some time 
ago, on examining a tree which had been stripped of its bark 
by astroke of lightning, he found the inner surface of the bark 
to contain ramified impressions of the lightning, corresponding 
with those described in the above paper. Specimens of this 
bark were forwarded to Professor Faraday, and are now in the 
Museum of the Royal Institution of London. I hope to be 
able to describe the particulars of this case in the next number 
of this Journal. 3 
