FAKMERS' INSTITUTES. 253 



iug to do Ts-ith its conductiug power !" At this rate, we shall need an "advisory 

 council" to reconcile Mr. L. and the authorities he quotes. My question does not 

 lose force, Ijut acquires increased significance by his admission. Tlie quotation 

 from Memoirs d' Academic is true as applied to an "insulated prime conductor," 

 but false as applied to electrical conduction from place to place, which is the 

 cnly subject under discussion. Mr. L.'s confession confirms what I said in the 

 first place, that most of the authorities he quotes are speaking of electricity at 

 red and not of electricity in motion. 



Mr. L. endeavors to strengthen his position by quotations from correspondence 

 with scientific men in our country. His quotation from Prof. Douglas seems 

 to fully sustain liis position. I Avrote to Prof. Douglas, Feb. 38, calling his 

 attention by direct quotations to the fact that he had arrayed himself against 

 such men as Faraday, Miller, Deschanel, and De la Eive, and asked him 

 which was rio-ht ? I have not received an answer. 



He also quotes from Prof. B. Silliman, Jr. If we may trust the newspaper 

 reports from Washington, it seems that ''lightning has struck" in the vicinity 

 of the Emma mine ; and when Prof. Silliman satisfactorily explains his con- 

 nection with that stupendous fraud, and his receipt of a fee of 125,000 for 

 sending a dispatch which has disgraced the American name before the whole 

 civilized world, scientific men will be more ready to receive his opinion on other 

 scientific subjects. 



In regard to the quoted reply of Prof. Henry, I frankly confess that it filled 

 mo with astonishment. The only reply I now make to his letter is that he has 

 arrayed himself in direct opposition to the great mass of scientific men in Europe 

 and America. Let me quote a few authorities to sustain this position, in addi- 

 tion to those I quoted in my former article. 



Gmelin, under the head of frictional electricity, says: "The conducting 

 power of a wire of any given metal varies directly as its transverse section and 

 inversely as the square of its length." — Vol. L, p. 310. 



Watts in his Chemical Dictionary says : "The resistance of a wire or any 

 other conductor of given length varies inversely as its transverse section." — Vol. 

 IL, p. 4G6. 



James Clerk Maxwell, professor of experimental physics in the university of 

 Cambridge, England, has written a work on electricity and magnetism in two 

 large octavo volumes, in Avhich he makes a rigid application of mathematics to 

 the problems in electricity. When speaking of electricity at rest he always 

 treats it as having tu'o dimensions (surface) ; but when speaking of conduction, 

 he treats it as having three dimensions. "In the one case it involves s2«'/ace 

 only; in the other case it involves length and area of the conductor." Thus, he 

 says : "If the conductor is to be treated not as a line but as a body, we must 

 express the force on the element of length, and the current through the com- 

 plete section, in terms of symbols denoting the force per unit of volume, and 

 the current per unit of area." — [Vol. II., p. 226.] He then goes on to say: 

 "If S represent the section of the conductor," etc. 



A Cambridge professor would not apply the calculus of three dimensions in 

 discussing the mathematics of electrical conduction, if only two dimensions (or 

 surface) were involved. This work was issued at Oxford, England, in 187'3, 

 and is standard authority. 



John Scofiern, late professor of chemistry at the Aldersgate school of medi- 

 cine in England, in his Chemistry, p. 225, has a very forcible article on the 

 outsidedness of electricity, which would delight Mr. Lanphere ; and on p. 226 



