136 Lightning in relation to Crowds 



which the slates rest, become moist, and upon the great number 

 of iron nails which are required to fasten them. 



The more that any material possessed of conducting powers 

 is accumulated, whether in volume or weight, the greater, it 

 would appear, is the danger of the lightning inflicting injury 

 in the immediate vicinity. This being once admitted, since 

 living men are excellent conductors of the fulminating mat- 

 ter, the opinion of some able natural philosophers, and of M. 

 Nollet among others, should not be rejected, that the danger 

 of being struck in a church is augmented with the number 

 of individuals who are assembled. There is also another cause 

 which may contribute to make numerous assemblies of men and 

 of animals more dangerous during a thunder-storm. It is this, 

 their perspiration cannot fail to produce an ascending column of 

 vapour ; and every one knows that moist air is a much better 

 conductor of lightning than dry air ; and the column of air must 

 in preference conduct the lightning to the source whence it ema- 

 nates. We ought not, then, to be surprised that flocks of she^j 

 are so often injured, and that a single flash not unfrequently 

 destroys as many as thirty, forty, and even fifty of the flock. 



In America, it is an opinion very generally entertained, that 

 hams filled with grain or forage are more liable to be struck 

 than other kinds of buildings. This fact should probably also 

 be referred to an ascending current of moist air, whose origin 

 may be traced to the circumstance that thfe harvest is usually 

 housed before it has become thoroughly dried. 



A single person is sometimes struck in the midst of a nu- 

 merous group, without our being able to detect anything like 

 a determinate cause for this kind of selection, without his ha- 

 ving a greater quantity of metal about his person, or his ^osi- 

 iion appearing to be less favourable than that of his neighbours. 

 I say appearing less favourable, for a cause though invisible 

 may still be very active. Thus, a piece of iron for example, 

 enclosed in thick masonry, will act not less powerfully than if it 

 were exposed. Hence, it will but seldom occur that we can 

 • affirm that the positions, of the person struck and the person 

 spared, were in every respect identical ; for the latter may have 

 been further removed than the former from some hidden mass 

 pf metal, or some stream of water, or some other conductor hid 



