TKANSACTIONS OF SECTION A, 595 



did not know what it was, but in being possessed of this mania he might call it 

 self-induction— he had had self-induction before his eyes and seen nothing else, and 

 consequently had not studied Professor Poynting's paper to the advantage that one 

 would expect. If he had studied Professor Poyntings paper (who shows that 

 energy passed through the dielectric and not through the conductor) he might have 

 applied that principle to his experiments and proved with equal satisfaction to 

 himself that the peculiar effects that he produced were due to something or other 

 in the dielectric. But he was not sure that he would not find on further inquiry 

 into the matter that there was something between the dielectric and the_ conductor. 

 They knew that a conductor in contact with a dielectric in contact with air was 

 subject to an electromotive force. They knew when a row of people, for instance, 

 were collected together and a spark was passed through them those who suftered 

 were the two end ones. There were several instances on record where horses had 

 been ranged in a row, and the two extreme horses had been killed and the inter- 

 mediate ones not touched. That showed that there must be some effect between 

 the surface of the terminals and the air, of which at present they were ignorant. 

 He thought that that was a point that deserved experiments. Wires could be 

 obtained coated with various dielectrics. He could supply Professor Lodge, if that 

 gentleman would continue his experiments, with any quantity of wire covered with 

 gutta-percha, with paraflin, or with any other compound that was in the market. 

 Then, again, there was nothing analogous to the transformation of energy in those 

 experiments of Professor Lodge. Let his explanation be absolutely true ; let there 

 be self-induction in those alternative currents— he could not conceive from analogy 

 of any single effect of self-induction that would cause the electromotive force 

 between those two balls to increase from 100,000 to 140,000 volts. They had to 

 account for a great increase of electromotive force. Professor Lodge indicated in 

 his paper at Section A on Friday that a spark of one inch at a distance of three 

 yards increased to (he thought) fourteen inches. There they had an increase of 

 electromotive force that would be something like an increase from 100,000 volts to 

 1,000,000 volts, and they could not account for that by any known phenomenon 

 connected with self-induction. 



Well, those points, he thought, rather tended to shake one's confidence in the 

 oscillatory character of lightning, and in the influence of self-induction in deter- 

 mining the efficacy of lightning-protectors. 



The next fallacy of Professor Lodge that he wished to touch was one where he 

 asserted that a lightning-protector protected no area whatever. If a lightning- 

 protector raised above that building did not protect an area around and about that 

 building, what earthly use was there in a lightning- protector ? Well, they knew 

 from e\'idence in the" Report of the Lightning-rod Conference that areas were 

 protected, and he had in a paper in the ' Philosophical Magazine ' worked that out 

 in a way that he thought could scarcely be controverted. Again Professor Lodge 

 asserted that extended points were needless. Well, their Report on the Conference 

 said that extended points were necessary. Of course those two opinions were 

 diametrically opposed to each other. The Conference placed their stand upon the 

 experience of the past, and Professor Lodge placed his stand upon his mathematical 

 assumptions. 



Next as to iron. Professor Lodge advocated iron now, so did he. But he 

 found on November 3, 1887, in ' Nature ' — only last November— Professor Lodge 

 sa.ys : ' A lightning-conductor should not be a round rod, but a flat strip, or a 

 strand of wires with the strands as well separated as convenient, and though I have 

 not mentioned the special eftect of iron I may as well say here that iron is about 

 90,000 times worse than copper.' 



He had said something about mathematical developments, and he thought that 

 one of the serious errors committed by those who relied on mathematical develop- 

 ments was that of hasty generalisation. 



He had always held the belief that they would sooner or later trace an electric 

 current to be a mere vibration, a mere oscillation of the molecules that composed 

 the mass of their conductors. He carried out in Dr. "Warren De La Rue's labora- 

 tory a series of the most briUiant experiments with his great battery deflagrating 



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