8i8 THE POPULAR SCIENCE MONTHLY. 



its numerous iron rain-pipes, and this intelligibly accounted for its 

 own preservation through that portion of its course ; and it was also 

 clear that the earth communication of the conductor was not ample 

 enough for the transmission of the entire discharge, as, if it had been, 

 the lower part of the conductor would have been shattered like the 

 upper part, and the rain-pipe would have remained uninjured. The 

 resistance of the earth communication of the conductor, measured 

 through the uninjured fragment, was sixty-five ohms — that is, some 

 twelve or sixteen times greater than under any circumstances it ought 

 to have been. So far, therefore, from this maligned conductor being 

 open to reproach, it had done exactly what it was scientifically bound 

 to do, and what any expert could have foretold that it would do, 

 under the circumstances which have been described. 



But the critic who sounded the note of alarm in " The English Me- 

 chanic " was also egregiously wrong in another by no means unimpor- 

 tant particular. The unfairly maligned conductor had not " proved 

 worse than useless when a thunder-storm came." As some more ap- 

 preciative commentator figuratively but not inaptly remarked at the 

 time, it had " gallantly died at its post in the efiicient performance of 

 its duty." Although the lightning-conductor was destroyed, the ex- 

 ceedingly. beautiful stone spii'e remained absolutely uninjured. It had 

 not even a scar upon its face. Tliis circumstance of the destruction 

 of a lightning-rod of too narrow capacity without injury to the build- 

 ing to which it is attached is by no means of infrequent occurrence. 

 About five mches of the top of the second conductor which Franklin 

 himself erected in Philadelphia were destroyed by a discharge, which 

 was seen to strike the rod, and which also made itself visible in a lumi- 

 nous blaze in the dry earth around its base ; and Franklin adroitly 

 claimed the incident as a proof that Nature itself had borne testimony 

 in favor of his invention. The brass-wire conductor of the war-ship 

 Jupiter was struck at sea on June 13, 1854, and the sixty brass wires 

 of which it was composed were shattered into fragments the size of a 

 pin. But no injury was done to the vessel. A large number of in- 

 stances of a kind very similar to this well-known and altogether typi- 

 cal case might be adduced did space permit. But it must not there- 

 fore be inferred that so desirable a result is in the proper order of 

 events. When a lightning-rod " dies at its post " in a successful de- 

 fense, as in the memorable Chichester case, the auspicious issue is due 

 to the accidental circumstance that no better extraneous earth contact 

 is within the striking reach of the discharge. If this were the case, 

 the lightning would certainly be diverted from the course of the con- 

 ductor into the more facile way, and, in making its devious leap into 

 the more available path, would be quite sure to leave the marks of its 

 divergent passage in some undesirable form. It is on this account, as 

 well as because of the wasteful outlay which is required to supply a 

 new rod when an old one has been destroyed, that lightning-conduct- 



