Feb., 1915.] 
Efficacy of Lightning Rods. 
441 
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 fonn of rods. 
Summary of answers from Mutual Fire Insurance Com¬ 
panies, received by J. Warren Smith, 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 5678f 
For 1912. 92 191.009 469 756 088 154 24 14 3 31 
For 1913. 121 328,565 1,174 1,089 809 252 43 33 6 31 
For 5 vears. 51 94,797 465 660 456 155 21 11 1 34 
Misc. i J 18,155 591 495 245 71 0 0 0 55 
items 9 10 11 12 
For 1912. 8173,343.000 8362,009 8137,590 88,104 
For 1913. 249,883,000 572,344 198,581 4,949 
For 5 years. 63,026,000 185,963 71.442 270 
Misc. f. 6,771,000 159,920 48,252 0 
*Total number of insurance companies reporting, 
t Percentage of buildings rodded. 
t Summary from 5 different companies covering a term of years, the 
shortest being 13 and the longest 25 years. 
