TEE FEAR OF LIGETXIXG. 



3G9 



the risk, which may here be somewhat serious, ad- 

 vantage should be taken of whatever undulations 

 of surface may exist, to keep upon the lowest 

 ground. No doubt the prostrate position would 

 in these circumstances afford greater security 

 than the erect. 



It happens not unfrequently that animals are 

 killed by lightning under a tree to which they had 

 betaken themselves for shelter. In these cases 

 the tree is struck partly in consequence of its iso- 

 lation, and partly on account of the presence of 

 the animals beneath it. Usually there are several 

 and often many of them assembled together, hud- 

 dled probably by terror into contact one with an- 

 other. The air heated by their bodies rises above 

 them laden with moisture, derived mainly from 

 their breath. Who has not noticed the cloud of 

 vapor that in the early morning and in certain 

 states of the weather hangs over a flock of sheep 

 or a herd of kine ? The column of moist air as- 

 cending through the branches of the tree toward 

 the cloud, offers, in consequence of the compar- 

 atively high conductivity of water, a favorable 

 passage for the electricity. A herd of cattle un- 

 der an isolated tree is thus exposed to a double 

 risk ; also it is evident that these animals are in 

 the open country less secure from injury than 

 human beings, who cannot affect the atmosphere 

 in a like degree. 



The danger from lightning in a dwelling-house 

 is exceedingly small. The materials used in build- 

 ing are, with the sole exception of the metals, 

 very bad conductors ; and the form of a house is 

 not that which is favorable to the reception of an 

 electric charge. Towers and spires, the latter 

 especially, possess that form ; but these structures 

 are nearly always protected by conductors affixed 

 to them. It has been suggested that chimneys 

 may, through the conductivity of their soot-lin- 

 ing, attract lightning. But as communication 

 with moist earth is interrupted below the fire- 



place, the influence of the soot in diminishing the 

 total resistance is compensated. A house around 

 the roof of which there is a system of water-pipes 

 reaching to the ground is very effectually pro- 

 tected. The timid may, however, put their fears 

 to rest by affixing a conductor to the highest 

 chimney, and taking care that the lower end be 

 carried sufficiently deep into the ground to be 

 always in moist earth. 



A consideration of the preceding facts leads to 

 the conclusion that the risk of personal injury 

 from lightning is necessarily small. The condi- 

 tions favorable to the occurrence of accidents 

 are few and of such a nature that the combina- 

 tions requisite for their fulfillment cannot often 

 take place. There are but two situations in which 

 danger is to be apprehended — namely, on the por- 

 tions of a flat district that are destitute of trees ; 

 and beneath the branches of an isolated tree 

 standing in a spot that is not dominated at a 

 short distance by higher ground. But even here 

 the danger is not necessarily certain, for thunder- 

 clouds do not by any means invariably discharge 

 to the ground. 



The infrequency of accident from lightning is 

 known alike to those who are ignorant of the laws 

 which the storm obeys, and to those who can cor- 

 rectly estimate the risk from a full understanding 

 of the circumstances and conditions under which 

 its forces are set in action. This knowledge 

 should alone go far toward showing how ex- 

 aggerated are the alarms felt by the timid. But, 

 small as is the risk, it may be made still less by 

 an observance of the precautions which have 

 been here pointed out. Attention to these will 

 give almost perfect security to the person; and 

 a knowledge of this fact, combined with the 

 ability to accurately estimate the amount of risk 

 in all circumstances, should relieve the mind of 

 painful apprehensions. 



— Chambers's Journal. 



96 



