242 STATE BOAED OF AGKICULTUEE. 



it would make no difference ; but if not sufficieutly large, and the tube should 

 become heated, you might have a boiler explosion. 



Spencer Marsh, Allegan. — Why don't lightning-rod men iise the best ma- 

 terials ? 



Dr. Kedzie. — Because they want to make money. 



Dr. Thomas. — If we deal with lightuiug in motion, can we expect that a 

 stroke will be drawn to one of these rods? 



Dr. Kedzie. — The rods do not draw the electricit}^, but simply serve to con- 

 duct the electricity from their neighborhood. It is not a necessary proof of the 

 excellence of a rod that it is struck. 



Dr. Thomas. — What distance will one of these rods protect from lightning? 



Dr. Kedzie. — It dej^ends upon the tension of the electricity. The French 

 Academy of Science has claimed that a lightning-rod point upon a building will 

 protect a circle the diameter of which is four times the height of the rod. It is 

 not an invariable rule. 



Henry Shultes. — What produces the heating effects of electricity? 



Dr. Kedzie. — Kesistance to its passage. 



Kev. John Sailor. — Is it not friction? 



Dr. Kedzie. — You can hardly call it friction. Scientists call it the conver- 

 sion of force from one form to another. 



Dr. Amsden. — Is there any objection to allowing the rod to touch the side of 

 the house? 



Dr. Kedzie. — No. The building would be better protected by spiking the rod 

 against the side of the building. 



Spencer Marsh. — What objection would there be to a horizontal rod with four 

 points ? 



Dr. Kedzie. — The four rods might accumulate more electricity than one rod 

 could carry off. 



Dr. Thomas. — If one of these rods should attract the electricity, say 50 feet, 

 would the flash go out of its course to pass down the rod? 



Dr. Kedzie. — Most naturally. 



H. D. Dewey, Allegan. — Why are forest trees so often struck by lightning? 



Dr. Kedzie. — Because they are more elevated objects ; hence more exposed. 



W. W. W^arner, Allegan. — You recommend that the rod should be spiked to 

 the building? 



Dr. Kedzie. — It is just as good as any other way, and is less expensive. I do 

 not claim that this lightning-rod I have shown you is better than any other 

 lightning-rod, but it is just as good, and as cheap as can be made. 



B. D. Pritchard, Allegan. — There has been a rod sold in this county called 

 the Hall copper-sheet rolled rod, and instead of being insulated it is spiked to 

 the building. 



Dr. Kedzie. — Its conducting power is proportional to the transverse section 

 of the rod. 



H. G. Buck, Hopkins. — Where a man has eight rods on his barn, I want to 

 know if there wouldn't be terrible pulling and hauling? 



Dr. Kedzie. — No, sir, not necessarily. The more numerous the rods the 

 better the building would be j)rotected. 



H. G. Buck. — There was a stub standing near where I reside, about 60 feet 

 high, and 2|- feet in diameter. Lightning struck it, shivering it to the roots, 

 scattering the pieces in every direction to the distance of 20 or 30 rods. I want 

 to know if such a current of electricity could be carried off by such a rod as the 

 one you have shown? 



