Mr. C. Tomlinson on some Effects of Lightning. 115 



tree were described as having an exact portrait of the tree 

 impressed (or photographed, according to M. Poey) on the 

 body of the victim, whether man or beast. In 1861 I suc- 

 ceeded in transferring to a plate of glass an impress of the 

 discharge of a Leyden jar in all its minute details, consisting 

 of a main trunk (in some cases bifurcated and even trifurcated) , 

 branches, and spray. I exhibited these results before the 

 Physical Section of the British Association at Manchester in 

 1861, and the Astronomer Royal, who presided, remarked 

 that any one of my figures would pass for a tree all the world 

 over. In 1866 an account of a lightning stroke "with an 

 exact portrait of the tree on the body of the victim " appeared 

 in the ' Times.' A letter of mine in that paper on the 10th 

 of September explained how the ramified marks on the body 

 of the victim were impressed by the fiery hand of the light- 

 ning without any reference to the tree. Since that time many 

 similar cases have been recorded (in one case the tree-like 

 marks were photographed) and the correct explanation has 

 been given*. 



In some recent cases great surprise has been expressed that, 

 in a row of human beings or animals struck by lightning, the 

 first and the last were the victims, while the intermediate ones 

 escaped. Many such cases are recorded. A file of thirty- 

 two horse3 in a stable at Rambouillet was struck by lightning ; 

 the first was killed and the last severely wounded. The inter- 

 mediate thirty were only thrown down. Five children sitting 

 on the same form at school, at Knonau in Switzerland, were 

 struck ; the first and the last were killed, but the other three 

 escaped with a shock. In a line of conducting matter of 

 whatever material, the damage, if any, is where the lightning 

 enters and quits the conductor ; the intermediate bodies only 

 transmit the charge. Thus, a rod of metal acting as a con- 

 ductor may be fused at the two extremities. With more 

 imperfect conductors, such as the bodies of animals, there is a 

 greater resistance than in metal ; but any resistance in the 

 passage of the charge from one set of more or less perfect 

 conductors to another set may occasion some delay, and any 

 delay, even of a small fraction of a second, allows the heating 

 and expansive force of the lightning to accumulate and so to 

 develop its tremendous effects. 



In the cases above referred to, the individuals, whether 

 horses or children, were pretty much under the same con- 

 ditions. If, however, the conditions are not the same, the 



* Livingstone, in his ' Missionary Travels and Researches in South 

 Africa,' ltf/37, says : — " The lightning spread over the sky, forming eight 

 or ten branches at a time, in shape exactly like those of a tree." 



I 2 



