186 Mr. J. S. Townsend. 



detected for long distances. An effect was obtained at over half a 

 mile from the vibrator. 



(3) Waves along Wires. The uses of fine steel wires for examining 

 the distribution of currents along wires are explained. 



(4) Damping of Oscillations. A method of determining the damp- 

 ing of discharge circuits is investigated. The absorption of energy 

 in spark gaps is deduced, and the apparent resistance of the air break 

 to the discharge determined. 



(5) Resistances of Iron Wires. Quantitative results are given for 

 the resistance of iron wires for very rapid alternations. The value 

 of the permeability of the different specimens is deduced, and it is 

 shown to vary with the diameter of the wire and the intensity of the 

 discharge. 



(6) Absorption of Energy by Conductors. The absorption of energy 

 of iron and non-magnetic cylinders placed in solenoid through which 

 a discharge passed were determined. Iron cylinders were found to 

 absorb much more energy than copper ones of the same diameter, and 

 the permeability of the iron for the discharge is deduced. 



(7) Determination of the Period of Oscillation of Leyden Jar Dis- 

 charges. A method of accurately determining the period of oscillation 

 is based on the division of rapid alternations in a multiple circuit, one 

 arm of which is composed of a standard inductance, and the other of 

 a variable electrolytic resistance. 



The value of n, the number of oscillations per second, when the 

 currents in the branches of the multiple circuits are equal, is, under 

 certain conditions, given by 



R 



where B = resistance of electrolyte to the discharge, 

 W = value of the standard inductance. 



The value of the self-inductance and capacity of the discharge cir- 

 cuit for very rapid oscillations may also be experimentally deduced. 



" Magnetisation of Liquids." By JOHN S. TOWNSEND, M.A. 

 Dub. Communicated by Professor J. J. Thomson, F.R.S. 

 Received June 11, Read June 18, 1896. 



(Abstract.) 



The experiments on the coefficient of magnetisation of liquids were 

 made with a sensitive induction balance. Both circuits were com- 

 muted about sixteen times a second, so that very small inductances 

 could be detected by the galvanometer in the secondary circuit. The 

 principle of the method consisted in balancing the increase of the 



