4*68 Cambridge Philosophical Society, 



particle, but not by the forces, which act upon it, whilst they 

 are passing to the following molecule. As regards Weber's 

 theory of induction, it is unimportant whether this assumption 

 is made or not. If it be made, and the currents in the circuit 

 be regarded generally as in accordance with the view of the 

 electro-static law, it is a matter of indifference in regard to the 

 magnitude and the direction of the force which tends to sepa- 

 rate the electricities in the element % and therefore in regard to 

 the electro- motor force, as Weber calls it, whether we start 

 from the electro-static or Weber's law. The difference which 

 might possibly occur must therefore arise from the forces 

 exerted by the electricities flowing in the other parts of the 

 system; and these forces, according to what Weber has 

 pointed out, do not contribute to this electro-motive force, in- 

 asmuch as the currents are constant, and convey equal quan- 

 tities of both electricities with the same velocity in opposite 

 directions. 



LXV. Proceedings of Learned Societies, 



CAMBRIDGE PHILOSOPHICAL SOCIETY. 



[Continued from p. 233.] 



Feb. 11, A PAPER was read by the Master of Trinity, " Criti- 

 1850. jfJL cism of Aristotle's account of Induction." 

 The passage criticised was Analyt. Prior. 1 1 . 25, and is by Aris- 

 totle illustrated by this example. Elephant, horse, mule, &c.,are long- 

 lived ; but elephant, horse, mule, &c. have no gall-bladder. If we 

 suppose that the latter proposition may be converted and put in this 

 form, " all animals which have no gall-bladder are as elephant, horse, 

 mule, &c," we may draw the conclusion that all animals which have 

 no gall-bladder are long-lived. This convertibility and generalization 

 of the second proposition are the necessary conditions for translating 

 induction into syllogism. And Aristotle really contemplated such a 

 generalizing induction. He did not contemplate what has been 

 called inductio per enumeraiionem simplicem, which is really no induc- 

 tion at all. This was shown to be so by reference to the case, often 

 used as an example of induction, of the inference of Kepler's laws 

 from the observation of the separate planets. It may be objected 

 that the reasoning in such cases is inconclusive ; and to this it is 

 replied, that induction, as reasoning, is inconclusive. It is a source 

 of truth different from reasoning ; of first truths, the bases of rea- 

 sonings, as Aristotle has remarked. 



April 15. — On the Mathematical Exposition of some Doctrines of 

 Political Economy. By the Master of Trinity. 



The object of this paper was to solve algebraically certain pro- 



