Prof. Faraday on some Points of Magnetic Philosophy. 89 



N pole at the same end of the iron rod in the same position and 

 place. This would be to assume two kinds of magnetism, i. e. 

 two north fluids (or electric currents) and two south ; and the 

 northness of bismuth would differ from the northness of iron as 

 much as pole from pole. Still more, the northness of bismuth 

 and the southness of iron would be found to have exactly like 

 qualities in all points, and to differ in nothing but name ; and 

 the southness of bismuth and northness of iron would also 

 prove to be absolutely alike. What is this, in fact, but to say 

 they are the same ? and why should we not accept the confirma- 

 tion and unfailing proof that it is so, which is given to us expe- 

 rimentally by the moving wire ? (3307. 3356.) 



3312. If we employ a magnet as the originally inducing body 

 (3310.), and entertain the idea of magnetic fluids accumulated 

 at the poles, which act by their power of attracting each other, 

 but repelling their like, then the inconsistency of supposing that 

 the north fluid of a given pole can attract the north fluid of one 

 body and the south fluid of another, or that the north and south 

 fluids of the dominant magnet can attract one and the same fluid 

 in bismuth and in iron, &c, is very manifest. Or if we act by a 

 solenoid or a helix of copper wire carrying an electric current 

 instead of a magnet, and find that analogous effects are produced, 

 are we to admit at once that the electric currents in it, acting 

 upon the assumed electric circuits round the particles of matter, 

 sometimes attract them on the one side and sometimes on the 

 other ? or if such bodies as bismuth and platinum are put into 

 such a helix, are we to allow that currents in opposite directions 

 are induced in them by one and the same inducing condition ? 

 and that, too, when all the other phsenomena, and there are 

 many, point to a uniformity of action as to direction with a varia- 

 tion only in power. 



Media. 



3313. Let us now consider for a time the action of different 

 media, and the evidence they give in respect of polarity. If a 

 weak solution of protosulphate of iron*, m, be put into a selected 

 thin glass tube about an inch long, and one-third or one-fourth 

 of an inch in diameter, and sealed up hermetically (2279.), 

 and be then suspended horizontally between the magnetic poles 

 in the air, it will point axially, and behave in other respects as 

 iron ; if, instead of air between the poles, a solution of the same 

 kind as m, but a little stronger, n, be substituted, the solution in 

 the tube will point equatorially, or as bismuth. A like solution 

 somewhat weaker than /«, to be called /, enclosed in a similar 



* Let / contain 4 grains, m 8 grains, n 16 grains, and o 32 grains, of 

 crystallized protosulphate of iron in each cubic inch of water. 



