Feb., 1915.] Efficacy of Lightning Rods. 44i 



The all important thing seems to be to have a continuous 

 conductor from the highest points on the building to permanently 

 moist earth beneath. The kind of material does not seem to be 

 so important as to be sure of frequent inspection, good grounds, 

 and constant care that there are no poor or broken joints, or rusted 

 and broken sections. The general opinion seems to be that the 

 rods should be fastened directly to the side of the buildings without 

 insulators and that all heavy masses of metal like hay tracks, 

 etc., should be fastened to the lightning rods. 



The Installation of Lightning Rods. — While lightning rods 

 should be carefully installed yet their erection involves no more 

 wonderful or mysterious process than building a fence or digging 

 a well. 



The statement by some lightning rod agents that no one but 

 a special scientist versed in all the laws of electricity should_ do 

 the work of putting up lightning conductors, is about as sensible 

 as to say that no one but a professor in geometry should be allowed 

 to lay brick. 



And not only that, but any professional in the lightning rod 

 business who advocates that his system is the only one that is 

 scientifically correct and reliable, while all others are worthless 

 and dangerous, invites the suspicion that he is himself a faker and 

 charlatan. 



Iron rods have some advantages over copper, but iron should 

 be used only where it will be frequently inspected and kept 

 painted. A 3-8 inch seven-strand, double galvanized iron cable 

 is recommended and may be put up by the owner himself. Copper 

 conductors should be soft drawn in the form of either tape or 

 stranded cable. The National Beard of Fire Underwriters 

 for Protection Against Lightning make definite recommendations 

 as to kind and form of rods. 



vSummary of answers from Mutual Fire Insurance Com- 

 panies, received by J. Warren vSmith, in August and Septem- 

 ber, 1914. A copy of the letter is attached. The columns are 

 numbered to agree with the questions : 



ITEMS * 1 2 3 4 5 6 7 8 f 



For 1912 92 191,009 469 756 588 154 24 14 3 31 



For 1913 121 328,565 1,174 1,089 809 252 43 33 6 31 



For5vears 51 94,797 465 600 456 155 21 11 1 34 



Misc.' t t 18,155 591 495 245 71 55 



ITEMS 9 10 11 12 



For 1912 $173,343,000 $362,009 $137,590 $8,104 



For 1913 249,883,000 572,344 198,581 4,949 



For 5 years 63,026,000 185,963 71,442 270 



Misc. t 6,771,000 159,920 48,252 



*Total number of insurance companies reporting. 

 t Percentage of buildings rodded. 



X vSummary from 5 different companies covering a term of years, Ihe 

 shortest being 13 and the longest 25 years. 



