On the Actio?i of a Magnet on Chemical Action. 105 



As the double salt was always partly undissolved, and as the 

 values of i for CuSO^ and for (NH 4 ),S0 4 are 098 and 2'0, 

 we have the relation 



0*49 log C Cu so 4 — log (N h 4 ) 2 so 4 =K. 



The number found is 0'438 log C Cu so 4 - 



7. In conclusion, we may notice Le Ohatelier's experiments 

 on the equilibrium between basic mercuric sulphate and sul- 

 phuric acid (Comptes rendus, xcvii. p. 1565); 



Hg 3 S0 6 4- 2H 2 S0 4 ^3HgS0 4 + 2H 2 0. 



In this case the values of i for H 2 S0 4 and HgS0 4 are 2*06 

 and 0*98, and we have 



1-4 log C H . 2 so 4 — log C Hg so4=K. 



The found value is 1*58 log Ch 2 so 4 - 



Generally speaking, therefore, such results show a very 

 satisfactory agreement. 



XIII. On an Explanation of the Action of a Magnet on 

 Chemical Action. By Henry A. Rowland and Louis 

 Bell*. 



IN the year 1881 Prof. Remsen discovered that magnetism 

 had a very remarkable action on the deposition of copper 

 from one of its solutions on an iron plate, and he published an 

 account in the American Chemical Journal for the year 1881. 

 There were two distinct phenomena then described — the deposit 

 of the copper in lines approximating to the equipotential lines 

 of the magnet, and the protection of the iron from chemical 

 action in lines around the edge of the poles. It seemed pro- 

 bable that the first effect was due to currents in the liquid pro- 

 duced by the action of the magnet on the electric currents set 

 up in the liquid by the deposited copper in contact with the 

 iron plate. The theory of the second kind of action was 

 given by one of us, the action being ascribed to the actual 

 attraction of the magnet for the iron, and not to the magnetic 

 state of the latter. It is well-known since the time of Faraday 

 that a particle of magnetic material in a magnetic field tends 

 to pass from the weaker to the stronger portions of the field ; 

 and this is expressed mathematically by stating that the force 

 acting on the particle in any direction is proportional to the 



* Communicated by the Authors, having been read at tne Munchester 

 Meeting of the British Association, September, 1887. 



