381 



and <p being any function whatever. The author then details the 

 processes by which he arrives at the solution of this latter problem. 



March 17, 1836. 



Sir JOHN RENNIE, Knt., Vice-President, in the Chair. 



Major T. Seymour Burt, Bengal Engineers, was elected a Fellow 

 of the Society. 



A paper was read, " On the reciprocal attractions of positive 

 and negative electric Currents, whereby the motion of each is alter- 

 nately accelerated and retarded." By P. Cunningham, Esq., Sur- 

 geon R.N. Communicated by Alexander Copland Hutchison, Esq., 

 F.R.S. 



The author found that a square plate of copper, six inches in dia- 

 meter, placed vertically in the plane of the magnetic meridian, and 

 connected with a voltaic battery by means of wires soldered to the 

 middle of two opposite sides of the plate, exhibited magnetic polarities 

 on its two surfaces, indicative of the passage of transverse and spiral 

 electrical currents, at right angles to the straight line joining the 

 ends of the wires. The polarities were of opposite kinds on each 

 side of this middle line, in each surface ; and were reversed on the 

 other surface of the plate. The intensities of these polarities at every 

 point of the surface were greatest the greater its distance from the 

 middle line, where the plate exhibited no magnetic action. The au- 

 thor infers from this and other experiments of a similar kind, that each 

 electric current is subject, during its transverse motion, to alterna- 

 tions of acceleration and retardation, the positive current on the one 

 side of the plate and the negative on the other, by their reciprocal at- 

 tractions, progressively accelerating each other's motions, as they 

 approach, in opposite directions, the edge round which they have to 

 turn. After turning round the edge their motion will, he conceives, 

 be checked by coming in contact with the accelerated portions of the 

 opposing currents to which they respectively owed their former in- 

 crease of velocity j so that the one current will be retarded at the 

 part of the plate where the other is accelerated. To these alternate 

 accelerations and retardations of electric currents during their pro- 

 gressive motion, the author is disposed to refer the alternate dark and 

 luminous divisions in a platina wire heated by electricity, as was 

 observed by Dr. Barker. 



" Meteorological Journal kept at Allenheads, near Hexham." By 

 the Rev. William Walton. Communicated in a letter to P. M. Roget, 

 M.D., Sec. R.S. 



This Journal contains a register of the height of the barometer, 

 taken at 9 a.m. and at 3 p.m. during every day in January and 

 February 1836, with remarks on the state of the weather during a 

 few particular days. The station where the observations were made 

 is elevated 1400 feet above the level of the sea. 



