FAKMERS' mSTITUTES. 341 



couiilings." Cut a thread on both ends of the bars, and then yon can easily 

 screw them together by means of tlie gas-pipe coupling. Paint the rod, and 

 especially all the Joints, with lamp-black and oil, to prevent rusting. 



3d. Carry the lower end of your rod down to permanently moist earth. This 

 is absolutely necessary for safety. Carry it into the well if convenient (bnt not 

 into the cistern), but at any rate carry it down to earth that never dries. Fill 

 the hole in the ground around the rod with powdered charcoal, because it is a 

 a better conductor than the soil, protects the rod from rusting somewhat, and 

 is very slow to dry when once wet. 



4th. Spike or clamp your rod securely against the side of your building. All 

 efforts at insulation are useless if you have a good rod and good ground con- 

 nections. 



5th. Protect the most exposed parts of your building : the chimneys of your 

 house and tlie ventilator of your barn. Carry your rod as high as you can 

 above the highest point of your building, and still have it well supported, so 

 that the Avind will not blow it over. 



6th. Bring the rod in metallic connection with any large masses of metal in 

 your building, — with the eave-trough, gas-pipe, etc. 



COST OF SUCH A ROD. 



In estimating the cost of such a rod, I leave out of account the Avork of tlie 

 farmer in putting it up, and of the blacksmith in bending the rod and cutting 

 the screws. I make an estimate of the cost of 100 feet of such lightning rod : 



100 feet f -inch rolled iron=150 pounds at 4c. - - ^6 00 



Lightning-rod point 50 



9 gas-pipe couplings, -^-inch 50 



Paint and painting rod 50 



Total cash cost for 100 feet.. $7 50 



A much poorer quality of rod, put up by lightning-rod peddlers, would cost 

 from 835 to 875. 



The difference, or $27 50 to 867 50, is the amount which the farmer may 

 save by putting up his own rod, and having at the same time a much better rod. 

 Is this sum worth saving in these hard times? 



DISCUSSION AT ALLEG.IN. 



L. B. Phillips, Allegan. — If glass insulators are of no special benefit, why do 

 telegraph companies use them? 



Dr. Kedzie. — In one case men manufacture their own electricity, and want 

 to save it ; in the other case another party manufactures it, and men want to 

 dispose of it. 



Mr. Phillips. — I believe that gold melts at a Ioav temperature. 



Dr. Kedzie. — It melts at about 2,000°. 



Mr. Phillips. — Then if these points are plated Avith gold Avill not that melt off? 



Dr. Kedzie. — It won't melt off for the reason that the gold is in contact with 

 a good conductor. To illustrate : if you take a silk handkerchief Avitli a back 

 of metal, you can place a live coal on it Avithout burning the handkerchief. 



Dr. E. Amsden, Allegan. — If we had a tube filled with Avater Avould that not 

 make a better conductor than the ordinary lightning-rod? 



Dr. Kedzie. — If the tube Avas sufficiently large to convey aAvay the electricity 



31 



