250 Mr Sedgiuick, on a Peripatus from Natal. [Nov. 9, 



(2) On an experiment of Sir Humphry Davy's. By G. F. 0. 

 Searle, M.A., Peterhouse. 



Two copper wires are passed up through holes about 5 centi- 

 metres apart in the bottom of a flat trough, their ends being level 

 with the surface of the trough. Mercury is then poured into the 

 trough to a depth of about 4 millimetres. On sending a powerful 

 current through the mercury by means of the two wires the 

 mercury in the immediate neighbourhood of the electrodes was 

 elevated into a small cone 2 or 3 millimetres in height. 



(3) Some notes on Clark's Cells. By R T. Glazebrook, M.A., 

 Trinity College, and S. Skinner, M.A., Christ's College. 



The paper relates to the causes of the variation of electromotive 

 force of the cells. In addition to the causes indicated by Lord 

 Rayleigh the authors find that the state of amalgamation of the 

 zinc pole may cause a fall in force if the zinc does not shew a 

 bright surface. This is worked out by means of a testing cell into 

 which the faulty zincs are transplanted. The result is confirmed 

 by Swinburne's experiments on zinc rods in zinc sulphate solution. 

 To correct this fault previous amalgamation in the presence of 

 dilute sulphuric acid is recommended, or immersion of the zinc in 

 the paste. Dr Hopkinson's method of testing cells by tapping 

 was shewn. 



(4) Illustrations of a Method of Measuring Ionic Velocities. 

 By W. C. D. Whetham, B.A., Trinity College. 



(5) On Gold-Tin Alloys. By A. P. Laurie, M.A., King's 

 College. 



November 9, 1891. 



Dr Gaskell in the Chair. 



The following Communications were made to the Society : 



(1) Note on a Peripatus from Natal. By A. Sedgwick, M.A., 

 Trinity College. 



[Received November 10, 1891.] 



Last spring I received from Mr P. S. Sutherland a single 

 specimen of Peripatus, which was found by Mr J. F. Quickett in 

 the Botanic Gardens of Pietermaritzburg, Natal. The specimen 

 possessed 22 pairs of claw-bearing legs, and presented all the 

 characters of P. Moseleyi, as described in my monograph of the 

 genus. 



