January, 1922. 



SCIENTIFIC AGRICULTURE 



149 



headway until many of the prominent pub- 

 lie buildings in Europe were protected. 

 Occasionally a building with rods on it 

 was damaged, and the opponents of course 

 seized upon these accidents to bolster up 

 their objections. The supporters, however, 

 studied all cases minutely in an endeavour 

 to perfect the system of protection and 

 thus avoid such occurrences. 



In America, where fine buildings were 

 less numerous, development was largely in 

 the direction of rodding rural buildings, 

 and the work was for the most part in the 

 hands of men who knew nothing about 

 electricity or the principles involved in 

 lightning protection ; hence the material 

 and installations were often inferior and 

 this led to losses which cast discredit, on 

 all rodding whether good or bad, not to 

 mention the lightning rod swindles that 

 were perpetrated. However during the last 

 twenty or twenty five years, a number of 

 lightning rod firms both in Canada and 

 the United States have been standardizing 

 the business, both as to material and 

 workmanship and thus raising the in- 

 dustry to a higher plane. In the midst of 

 this Agricultural colleges began to inves- 

 tigate the efficiency of lightning rods by 

 collecting data as to the comparative 

 damage done by lightning to rodded and 

 unrodded buildings. The Ontario Agricul- 

 tural College was fortunate in being the 

 first to obtain decisive results, and in 

 publishing its Bulletin 220, which esta- 

 blishes beyond possibility of doubt that 

 good lightning rods properly installed are 

 almost absolute protection against light- 

 ning. This conclusion was established 

 through data collected for the College by 

 the Mutual Insurance Companies. 



The method of calculating the efficiency 

 may be illustrated from data for 1912, the 

 first year for which the efficiency was 

 determined. In that year out of every 7000 

 unrodded buildings insured by the report- 

 ing companies 37 suffered damage by 

 strokes, several being burned completely, 

 and 37 claims were paid. But 7000 rodded 

 buildings insured by the same companies 

 suffered only 2 strokes, where at the same 

 ra'^e as the unrodded ones 37 would have 

 been expected. To prevent strokes or 

 damage in 35 out of an expectancy of 37 

 amounts to 94.50 percent. Since then re- 



sults have been obtained for the years 

 1913-15, showing that on the average the 



Putting points on copper finials. New Centre 

 Bloclc, Parliament Buildings, Ottawa. 



rods prevented 93.3 p. c. of all damages 

 that it was possible for them to prevent. 

 Similar results have since been calcu- 

 lated from available data in many States 

 of the American Union. Hence .just as 

 lightning rods were first invented and 

 used in America similarly the first com- 

 pilation of data establishing their effi- 

 ciency was also made on this continent. 

 Indeed we are not aware that such com- 

 pilations have even yet been made in 

 Europe. 



Although 6.7 percent of the rodded 

 buildings expected to be struck have ae- 

 tuall}^ suffered, yet the damage done has 

 not been so high, for when a rodded 

 building is struck even though the rods 

 and installation be poor the damage is 

 lighter than on an unrodded one. If yf^ 



