326 The Farmstead 



can be largely eliminated from a lightning dis- 

 charge. 



PROTECTING WOODEN ROOFS 



If a metal roof is out of the question, the 

 protection of the wooden roof must be provi- 

 ded for. Very little attention has been paid in 

 this country to the proper erection and main- 

 tenance of lightning rods. It is not sufficient 

 to put up a point in an out-of-the-way place, 

 and with a careless ground connection, and then 

 expect immunity from lightning. The lightning 

 rod will protect a wooden -roofed building if it 

 is properly installed ; and in order that this 

 simple but important piece of apparatus be 

 thoroughly understood it will now be considered 

 in detail . 



In the first place, it should be noted that 

 there are two forms of electric discharge or 

 lightning which are provided for in equipping a 

 building with lightning protection : the brush 

 discharge and the disruptive discharge. The 

 brush - form is so named because the fine 

 streamers of sparks which are emitted have 

 somewhat the appearance of a brush. This dis- 

 charge is harmless, and one of the important 

 functions of the bunch of points on the upper 

 end of the lightning rod is to quietly take from 

 the surrounding atmosphere the electricity there 



