32 Notice of Anniversary Meeting. [Nov. 18, 



the opposite side and the two ends of the box are far enough off that 

 they may be regarded as practically at an infinite distance from the 

 electrodes. 



"When c=l, the equation becomes r 2 = r^ r 2 : so that the section of 

 the cylindrical surface is a rectangular hyperbola. 



A curve determined by experiment is drawn in Plate 2. fig. 12, very 

 near to the position of this hyperbola ; but as one of the electrodes 

 was at the centre of the box, the forms of the equipotential curves will 

 be slightly changed, because of the influence of the opposite side and 

 ends of the box. 



At the vertex the two curves coincide, and, measured along the latus 

 rectum of the hyperbola, the distance between them is only 5 millims. 

 Since the distance between the battery-electrodes is one half the breadth 

 of the box, the influence of the opposite side and ends of the box will be 

 quite sufficient to account for so small a difference. Thus we see that 

 with linear electrodes there is a very satisfactory agreement between 

 theory and experiment. 



The equipotential curves for Case 10, with linear electrodes in the 

 liquid, are theoretically the same as those for Case 5, with points on a 

 sheet of tinfoil for electrodes. A comparison of the figures (Plate 1. 

 fig. 5 and Plate 2. fig. 12) which are laid down from the experimental 

 results shows how closely they agree, and may be taken to be an inde- 

 pendent proof of the accuracy of the theory of electrical distribution. 



November 18, 1875. 



Dr. J. DALTON HOOKER, C.B., President, in the Chair. 



In pursuance of the Statutes, notice of the ensuing Anniversary 

 Meeting was given from the Chair. 



Mr. Etheridge, Mr. F. Galton, Mr. Newmarch, Dr. W. Pole, and Mr. W. 

 W. Smyth, having been nominated by the President, were elected by ballot 

 Auditors of the Treasurer's Accounts on the part of the Society. 



Mr. Robert Lewis John Ellery (elected 1873), Mr. James Greikie, Dr. 

 Emanuel Klein, Prof. E. Ray Lankester, Mr. Robert Stirling Newall, and 

 the Earl of Carnarvon were admitted into the Society. 



The following extract from the Will of the late Sir Charles Wheatstone, 

 E.R.S., in a letter from Mr. Robert Sabine, one of the executors, was 

 read : — " I leave to the Royal Society of London for the Promotion of 

 Natural Knowledge the Portrait of the Hon. Robert Boyle, and all the 

 framed Portraits of scientific men now in my possession ; and I also 

 bequeath to the said Royal Society the sum of Eive Hundred Pounds, to 

 be applied to the purposes of the Wollaston Donation Eund." 



