FARM BUILDINGS. 255 



that brick or stone should take their place. They are more 

 durable, arc less exposed to fire, and they sustain a more 

 equable temperature in the extremes of the seasons. Barns 

 and, sheds cannot like houses, be conveniently made rat proof, 

 but they may be so constructed as to afford them few hiding 

 places, where they will be out of the reach of cats and terrier 

 dogs, which are always indispensable around infested prem- 

 ises. These and an occasional dose of arsenic, carefully and 

 variously disguised will keep their numbers within moderate 

 bounds. If poison be given, it would be well to shut up the 

 cats and terriers for three or four days until the object is 

 effected, or they too might partake of it. 



LIGHTNING RODS. 



In the hot, dry weather of our American summers, thun- 

 der showers are frequent and often destructive to buildings. 

 This danger is much increased for such barns as have just 

 received their annual stores of newly cut hay and grain. 

 The humid gases driven off by the heating and sweating 

 process, which immediatly follows their accumulation in 

 closely packed masses, offers a strong attraction to electri- 

 city, just at the time when it is most abundant. It is -then an 

 object of peculiar importance to the farmer to guard his build- 

 ings with properly constructed lightning rods, and they are a 

 cheap mode of insurance against fire from this cause, as the 

 expense is trifling and the security great. 



It is a principle of general application, that a rod will 

 protect an object at twice the distance of its height, above any 

 given point, in a line perpendicular to its upper termination. 

 Thus a rod attached to one side of a chimney of four feet 

 diameter, must have its upper point two feet above the chim- 

 ney to protect it. The height above the ridge must be at least 

 one half the greatest horizontal distance of the ridge from the 

 perpendicular rod. 



Materials and manner of construction. The rod may be 

 constructed of soft, round or square iron, the latter being 

 preferable, in pieces of convenient length and of not less than 

 4 o an inch in diameter. These should not be hooked into 

 each other, but attached either by screwing the ends together, 

 or forming a point and socket to be fastened by a rivet, so that 

 the rod when complete, will appear as one continuous surface 

 of equal size throughout. If a square rod be used, it will attract 

 the electricity through its entire length, if the corners be 

 notched with a single downward stroke of a sharp cold 



