of Electric Induction and Conduction. 367 



ment of the free atoms preponderate in one direction, it seems 

 worth while to try if incipient decomposition cannot be pro- 

 duced in a solution of double tartrate of iron, or other conve- 

 vient salt, by magnetism. One might use iron electrodes, care- 

 fully depolarized, connected with a galvanometer, and arranged 

 so that either can be magnetized at pleasure. The current 

 produced, if too feeble to be directly observed, might be detected 

 by using it to charge a condenser. But a more likely way 

 would be to send a current through the solution by a very 

 small external electromotive force, first in one direction and 

 then in the other, and to measure it each time ; in one case 

 iron would have to be carried against magnetic force, in the 

 other case with it (cf. Maxwell, art. 263). If the end of a mag- 

 net were cup-shaped and were filled with a magnetolyte, I sup- 

 pose that a continuous action would go on, tending to deepen 

 the hollow, because the middle of a magnet is magnetized 

 more feebly than the external portions. 



§ 15. If we make a heterogeneous electrolyte by taking a 

 number of strata of different materials, such a composite struc- 

 ture will not be capable of internal or of residual charge as 

 a composite dielectric is ; for the buttons remain at their proper 

 distance from one another on the cord, and this distance is the 

 same for all the different substances by Faraday's law. 



It is, however, possible for a body to possess the properties 

 both of an electrolyte and of a dielectric ; e. g. warm glass *. 

 The flow of a current through such a substance would be imi- 

 tated by making the connexions between the buttons and 

 rings in fig. 5 elastic strings instead of rigid rods. Internal 

 charge &c. would then be possible — not, indeed, as in an 

 ordinary dielectric, by slipping of the buttons on the cord, but 

 by unequal slipping of the rings on the rods. It may be that 

 conduction in dielectrics is always of this electrolytic nature, 

 and not metallic, as was imagined in fig. 1, § 2, &c. 



Electrolytic Momentum. 



§ 16. The mass of oxygen carried through the liquid in one 

 direction is eight times that of the hydrogen carried in the 

 same time in the opposite direction ; hence, so long as these 

 materials are being accelerated, it seems as if a momentum 

 should be imparted to the liquid as a whole, equal to the differ- 

 ence of momenta generated in the oxygen and hydrogen in 

 the same time. The acceleration lasts only the inappreciably 

 short time during which the current is assuming its constant 

 value. Let v be the velocity imparted to a mass m of hydro- 



* See Buff (Ann. cler Chemie unci Pharm.), quoted by Maxwell, art. 271 



