PROTECTION FROM LIGHTNING. 



47 



A singular freak of lightning is that of piercing bodies with 

 several holes in opposite directions. Of several recorded in- 

 stances the following' strikingly presents this remarkable char- 

 acteristic : In 1717, lightning struck a church in Cremona, 

 breaking the iron cross on its summit, and throwing to a distance 

 the weathercock which had been placed immediately below the 

 -■.. This weathercock was made of tinned copper and covered 

 with a coat of oil paint, and " was pierced by eighteen holes;" 

 the edges of nine of these holes stood out prominently on one of 

 thu faces of the weathercock, and the edges of the other nine 

 holes were equally prominent on the other side. There were no 

 indications which led the inhabitants of Cremona to suppose that 

 the weathercock had received several strokes of lightning. It 

 were remarkable indeed that the strokes should be in pairs ; nine 

 on each side, and in essentially parallel lines, as the nearly identi- 

 cal iuclination of the projecting edges would seem to require. Is 

 there not more reason for the belief that the eighteen holes 

 pierced in the Cremona weathercock were the result of a single 

 stroke ? Other instances of bodies pierced by lightning in a 

 similar manner, largel} 7, confirm this view. As matter of fact, in 

 the case of the zigzag path of lightning, it is not always easy to 

 determine whether the stroke be downwards or upwards. There 

 are physicists who regard .the very general appearance of down- 

 ward strokes of lightning an occular illusion. With a movement 

 so rapid, and with the notion or expectation of a downward stroke 

 by which the mind is pre-occupied, it certainly would not be 

 strange if the eye, at times, were deceived. The clouds above 

 and the earth or the objects beneath, at the moment before an 

 electrical discharge, are in opposite electrical conditions, and 

 when the tension of the electric fluids (to use the ordinary mode 

 of expression,) becomes too great for the resistance presented by 

 the atmosphere, they rush together producing the spark or flash — 

 and thus the electrical equilibrum is restored. An object may, 

 therefore, receive the stroke from the earthward side, (of which 

 numerous instances are on record,) or even from both sides 

 simultaneously. 



The power of lightning to shatter into pieces the object struck, 

 and to project or transport heavy bodies, is matter of frequent 

 observation. These results can hardly be supposed to follow from 

 the mechanical shock produced by lightning, and hence the 

 hypothesis that some other force is brought into action. This 



