ELECTRICITY. 93 



electric current appears to have a magnetic action, in a direc- 

 tion cutting its own at right angles ; or, supposing its section 

 to be a circle, tangential to it ; if, then, we reverse the posi- 

 tion, and make the electric current form a series of tangents 

 to an imaginary cylinder, this cylinder should be a magnet. 

 This is effected in practice by coiling a wire as a helix or spiral, 

 and this, when conducting an electrical current, is to all intents 

 and purposes a magnet. A soft iron core placed within such 

 a helix has the property of concentrating its power, and then 

 we can, by connection or disconnection with the source of 

 electricity, instantly make or unmake a most powerful 

 magnet. 



We may figure to the mind electrified and magnetised 

 matter, as lines of which the extremities repel each other in a 

 definite direction ; thus, if a line A B represent a wire affected 

 by electricity, and superposed on C D, a wire affected by mag- 

 netism, the extreme points A and B will be repelled to the 

 farthest distances from the points C and D, and the line A B 

 be at right angles to the line C D ; and so, if the lines be sub- 

 divided to any extent, each will have two extremities or poles 

 repulsive of those of the other. If the line of matter affected 

 by electricity be a liquid, and consequently have entire mobi- 

 lity of particles, a continuous movement will be produced by 

 magnetisation, each particle successively tending, as it were, 

 to fly off at a tangent from the magnet : thus, place a flat dish 

 containing acidulated water on the poles of a powerful mag- 

 net, immerse the terminals of a voltaic battery in the liquid 

 just above the magnetic poles, so that the lines of electricity 

 and of magnetism coincide ; the water will now assume a 

 movement at right angles to this line, flowing continuously, as 

 if blown by an equatorial wind, which may be made east or 

 west with reference to the magnetic poles by altering the 

 direction of the electrical current : a similar effect may be 

 produced with mercury. These cases afford an additional 

 argument to those previously mentioned, of the particles of 

 matter being affected by the forces of electricity and mag- 

 netism in a way irreconcilable with the fluid or ethereal 

 hypothesis. 



The representation of transverse direction by magnetism 



