452 Prof. Williamson on the Dynamics 



or, what is the same thing, 



whence approximately 



and thence to the third order in x, y, 



which is of the form in question. 



5 Downing Terrace, Cambridge, 

 November 2, 1863. 



LXV. On the Dynamics of the Galvanic Battery. 

 By Professor A. W. Williamson*. 



IN the title given to this evening's discourse, I have used a 

 hard word — Dynamics, which suggests the study of active 

 forces, and of calculations about those forces. I thought it was 

 no more than fair to put such a hard word into the title of the 

 discourse, because the title was intended as some sort of descrip- 

 tion of the thing itself; and there is no doubt that the matter 

 which I have to bring under your consideration tonight requires 

 for its appreciation some of that sustained and careful attention 

 which is given to mathematical subjects. The conclusion, of 

 which it will be my endeavour to convince you, depends on a 

 chain of facts : each link of the chain is a very simple fact, but 

 yet, if we lose one of them, the chain is broken, and the conclu- 

 sion falls to the ground. Having given you this warning of a 

 very dry discourse, I am bound to state, in mitigation, that of 

 actual calculations we shall only need addition and subtraction. 

 I have on this table a couple of stout copper wires, one of 

 which is in contact with one pole of a Grove's battery of 100 

 cells, whilst the other wire is in contact with the other pole. 

 They are very quiet common -place looking copper wires, though 

 capable of giving signs of their pent-up energies; and if I were 

 to disconnect them from the poles of the battery, they would be 

 found just like any other copper wires ; but whilst in contact 

 with the respective poles, these wires are endowed with latent 

 energies which, according to the direction given to them, are 

 capable of producing effects the most varied and the most mar- 



* Communicated by the Author, having been delivered at the Newcastle 

 Meeting of the British Association, August 28, 1863. 



