iO2 Traces of Unity in the Various 



the oxyhydrogen light, is, by raising the shutter, permitted 

 to impinge upon the plate, the needles are deflected. 

 Thus, light being the initiating force, we get chemical 

 action on the plate, electricity circulating through the 

 wires, magnetism in the coil, heat in the helix, and 

 motion in the needles." 



There are many facts which seem to connect mag- 

 netism with a particular state of matter. One of these is 

 to be found in a beautiful experiment by the author of the 

 Correlation of the Physical Forces, of which this account 

 is given, "A tube filled with the liquid in which 

 magnetic oxide of iron had been prepared, and ter- 

 minated at each end by plates of glass, is surrounded 

 by a coil of coated wire. To a spectator looking 

 through this tube a flash of light is perceptible when- 

 ever this coil is electrized, and less light is transmitted 

 when the electrical current ceases, showing a symmetri- 

 cal arrangement of the minute particles of magnetic 

 oxide while under the magnetic influence. In this 

 experiment it should be borne in mind that the particles 

 of oxide of iron are not shaped by the hand of man, as 

 would be the case with iron filings, or similar minute 

 portions of magnetic matter, but, being chemically 

 precipitated, are of the form given them by nature." 

 Another fact, scarcely less striking, is to be found in the 

 action of a magnet upon a ray of polarized light. If this 

 ray be passed through a column of water or any other 

 transparent liquid or solid which is equally incapable of 

 deflecting the plane of polarization, in a direction which 

 corresponds to the line of magnetic force the line, that 

 is, which unites the poles of the magnet the column 

 acquires, with reference to the light, the property 

 belonging to oil of turpentine and certain other bodies, 

 of rotating the plane of polarization, to the right if the 



