FAKMEKS' INSTITUTES. 255 



"Amherst College, March 11, 1876. 

 " E. C. Kedzie, M. D., Dear Sir : — Yours of the 7th iust. is just received. My opinion 

 on the subject proposed rests on the authority of such men as are named on the slip 

 accompanying- your letter. * * * For many years I have taught that the amount 

 of electricity that can be contained in a state of rest in an insulated conductor 

 depends on its extent of surface, and easily prove it by experiments; but that the 

 power to conduct electricity from one place to another (the length and material being 

 given) depends on the area of the cross section, and not on the amount of surface. 



* * * And I know of no authorities opposed to it. 



"The above answers questions 1 and 2. It follows that increasing the surface with- 

 out increasing the area of the cross section does not increase the conducting power of 

 a lightning-rod. 



"3. A tube and a solid rod being made of the same metal and having the same length 

 and diameter, the rod will conduct as much better as its cross section is greater in 

 area; or, which amounts to the same thing, as its weight per linear foot is greater. 



* * * The 'lightning-rod dealer' probably misunderstands statements made by 

 American authors. * * * 



"I have known students and 'peddlers' to jump at once to the conclusion that the 

 law would be the same in both cases, which is contrary to established facts. 



Yours truly, E. S, Snell." 



The third letter is from Ogxlcn Is. Rood, Professor of Physics in Cokimbia 



College, New York city : 



" Columbia College, March 15, 1876. 



Prof. R. C. Kedzie, Dear Sir: — I have received yours of March 7, containing three 

 questions to which you desire answers. Your first question is as follows : ' Are'Milier, 

 Faraday, De la Eive, and Deschanel correct in the positions quoted in the printed 

 slip, or is the old idea that atmospheric electricity is conveyed by mere surface action 

 the received opinion?' to which I would answer that according to my opinion and that 

 of the whole body of physicists, as far as I know it, the authorities quoted by you are 

 correct. Question 2: 'Does increased surface, as in a tube, give any increased con- 

 duction of lightning?' Xo. Question 3: ' Will a tube of any given metal aftbrd bet- 

 ter conduction than a solid bar of the same diameter?' Xo. 



" Very respectfully, 



Ogden N. Eood." 



With such indorsements of my position by Yale college, Amherst college, and 

 Columbia college, I am satisfied to rest my case. 



I am not surprised that Mr. Lanphere strikes out wildly to defend his posi- 

 tion. "When a man ''has a soft thing," selling his wares at a very large profit, 

 and when tliese special wares are chiefly in demand because of popular error on 

 a scientific point, it is natural that such a man should keenly resent the intru- 

 sion of science which destroys his lucrative monopoly. This is no new exhibi- 

 tion of human weakness. In an old and trustworthy Ijook I find the following : 

 ''And at the same time there arose no small stir alDOut that vray. For a certain 

 man named Demetrius, a silversmith, Avhich made silver shrines for Diana, 

 brought no small gain unto tlie craftsmen ; whom he called together with the 

 workmen of like occupation, and said, ' Sirs, ye know that by this craft we 

 have our wealth. * * * Not only this our craft is in danger to be set at 

 naught, but also that the temple of the great goddess Diana should be despised, 

 and her magnificence should be destroyed, whom all Asia and the world wor- 

 shippeth.' And when they heard these sayings tliey were full of wrath, and 

 cried out, saying, 'Great is Diana of the Ephesians.' " 



Human nature is much the same, whether at Ephesus or at Coldwater ! 



State Agkicultueal College, Lansing, March, 1876. 



