LIGHTOTNG-KODS. 



The humid gases, generated by the heating and sweating 

 of the hay, which immediately follows its accumulation 

 in closely-packed masses, offers a strong attraction to elec- 

 tricity, just at the time when it is most abundant. It is an 

 object of peculiar importance to the farmer to guard his 

 buildings, at such times, with properly constructed light- 

 ning-rods ; and they are a cheap mode of insurance against 

 fire from this cause, as the expense is trifling and the security 

 great. 



As an example of the more elaborate style of rods, we 

 show in the accompanying cut the manner in which Otis' 

 Patent Lightning-Rods have been applied to the New York 

 State Arsenal. 



To construct a lightning-rod. 



Take round or square soft iron f- of an inch in diameter, 

 in pieces of convenient length ; connect the pieces by split- 

 ting one end and flattening and inserting the other, and 

 fasten with a rivet or screw, so that the rod preserves its 

 uniform thickness throughout. Or, the pieces may be con- 

 nected in a more perfect manner, although not often so con- 

 venient, by having a male screw cut* on one end of the pieces 

 and a female screw on the other, and simply screwing them 

 together as the rod is raised; care being taken that the 



