8i6 THE POPULAR SCIENCE MONTHLY. 



to do away altogether with the lightning-rod as a dangerous and su- 

 perfluous expedient, and to establish in its place a system of earth-buried 

 plates and short earth-points surrounding the building. Space does 

 not here permit an allusion to the various fallacies which are involved 

 in this heretical scheme. It will be enough for all practical purposes 

 to say that the proper answer to the dangerous heresy is an appeal to 

 the argument of facts. There are innumerable instances on record in 

 which lightning has been seen to strike lightning-conductors with a 

 luminous flash, and there are still more in which the extremity of the 

 rod bears the traces of the passage through it of lightning ; but in 

 every case, if the rod has been of due size and properly constructed and 

 fixed, the building associated with it has been entirely uninjured. The 

 truth obviously is that the question of efliciency and safety entirely 

 hangs upon the amplitude of the dimensions, the number and position 

 of the points, and the completeness of the earth contact, of conductors. 

 In any case where these are insufficient the lightning-rod is a source of 

 danger. In every case where they are ample, and where the system of 

 theii- establishment is sound, the protection is complete. It will be 

 time enough to enter upon a consideration of the merits of the retro- 

 grade course which is advocated in this ill-advised scheme when any 

 single case of failure in a lightning-conductor of satisfactory dimen- 

 sions, and of tested perfection of construction, has been established 

 before a competent jury on incontrovertible grounds. The failures 

 incident upon defective work — as all unbiased and properly trained 

 thinkers are aware — are among the weightiest of the arguments that 

 tell in favor of the employment of conductors. 



In a very large majority of the cases in which accidents have oc- 

 curred to buildings which have been furnished with lightning-conduct- 

 ors, the mischief has been actually traced by competent inquiry to 

 some easily recognized fault or deficiency of construction. A very 

 instructive illustration of the accuracy of this remark has quite recently 

 presented itself in a form which is worthy of notice. Shortly after 

 midnight, on the 26th of November, during a thunder-storm of some 

 severity, a flash of lightning struck the lightning-conductor attached 

 to the spire of Chichester Cathedral, and scattered a considerable por- 

 tion of it into fragments. A letter from " A Fellow of the Royal As- 

 tronomical Society " forthwith appeared in the " English Mechanic and 

 World of Science," drawing attention to the accident, and commenting 

 upon it in the following words : " This seems to open a very serious 

 question indeed, because, if so elaborate an affair as the Chichester con- 

 ductor proved so much worse than useless when a thunder-storm came, 

 what security have we that a similar disaster may not befall at, say, 

 the Government magazines at Purfleet or elsewhere ? " In reference 

 to the accident which called forth this note of alarm, it may be at 

 once, however, said that it belonged essentially to the class of occur- 

 rences which have been pointed at in the beginning of this paragraph. 



