19G STATE BOARD OF AGRICULTURE. 



had been provided for it ; no more regard, in fact, than is required to 

 enable the greater part of it to take the good conductors, and to pre- 

 vent any part of it from being able to enter a perfectly inclosed metallic 

 building. 



Even a small lateral fraction of a flash is able, however, to ignite gas 

 if there is a leak, or even to make a leak at a "compo"-pipe where it 

 is crossed by a bell wire, and then ignite it; hence, after a building has 

 been struck, careful watch should be kept for some time against the 

 danger of fire. 



The amount of protection to be allotted to any building is no doubt 

 analogous to the question of insurance generally; that is to say, the 

 amount of premium it is desired to pay may be compared with the 

 capital at stake and the risk run; and this is doubtless a matter for 

 individuals and public bodies to consider for themselves. What the 

 committee can do is to make a study of cases of damage occurring to 

 buildings which on the old lines were supposed to be protected, to 

 tabulate them as below, and to ask for carefully recorded observations; 

 they can also draw up such hints and suggestions as may be of use 

 to architects whose clients desire their buildings to be protected in a 

 more thorough but not necessarily a more expensive manner. 



These objects, and these attempts at being useful, explain the exist- 

 ence of the present report." 



Also the following rules were laid down by the Committee: 



* RULES FOR THE ERECTION OF LIGHTNING CONDUCTORS, AS ISSUED BY THE 



LIGHTNING ROD CONFERENCE IN 1882, WITH OBSERVATIONS THEREON 

 ' ,^ BY THE LIGHNTING RESEARCH COMMITTEE, 1905. 



[Note. — Paragraphs beginning with odd numbers refer to Lightning 

 Rod Rules, 18'62; those with even numbers to Lightning Research Com- 

 mittee's observations, 1905.] 



1. Points. — The point of the upper terminal should not be sharp, 

 not sharper than a cone of which the height is equal to the radius of 

 .its base. But a foot lower down a copper ring should be screwed and 

 soldered on to the upper terminal, in which ring should be fixed three 

 or four sharp copper points, each about six inches long. It is desir- 

 able that these points be so platinized, gilded, or nickel plated as to 

 resist oxidation. 



2. It is not necessary to incur the expense of platinizing, gilding, 

 or electroplating. It is desirable to have three or more points beside 

 the upper terminal, which can also be pointed; these points must not be 

 attached by screwing alone, and the rod should be solid and not tubular. 



3. Upper terminals. — The number of conductors or points to be 

 specified will depend upon the size of the building, the material of 

 which it is constructed, and the comparative height of the several' parts. 

 No general rule can be given for this, but the architect must be guided 

 by the directions given. He must, hoAvever, bear in mind that even 

 ordinary chimney stacks, when exposed, should be protected by short 

 terminals connected to the nearest rod, inasmuch as accidents often 

 occur owing to the good conducting power of the heated air and soot 

 in the chimney. 



4. This is dealt with below in suggestion 3 (page 24). 



