338 Miscellaneous Intelligence* 



3. That these modifications, somewhat analogous to those sus- 

 tained by light and heat in similar circumstances, may serve to 

 explain the difference observed between the effects produced by a 

 pile composed of a great number of plates, and those produced 

 by a pile formed of a small number. — Ann. de Chim.f xxviii. 190. 



4. Electro-Magnetic Current, — As the current of electricity, pro- 

 duced by a voltaic battery when passing through a metallic con- 

 ductor, powerfully affects a magnet, tending to make its poles 

 pass round the wire, and in this way moving considerable masses 

 of matter, it was supposed that a reaction would be exerted upon 

 the electric current capable of producing some visible effect; and 

 the expectation being, for various reasons, that the approxima- 

 tion of a pole of a powerful magnet would diminish the current 

 of electricity, the following experiment was made. The poles 

 of a battery of from 2 to 30 4-inch plates were connected by a 

 metallic wire formed in one part into a helix with numerous con- 

 volutions, whilst into the circuit, at another part, was intro- 

 duced a delicate galvanometer. The magnet was then put, in va- 

 rious positions, and to different extents, into the helix, and the 

 needle of the galvanometer noticed ; no effect, however, upon it 

 could be observed. The circuit was made very long, short, of wires 

 of different metals and different diameters down to extreme fine- 

 ness, but the results were always the same. Magnets more and less 

 powerful were used, some so strong as to bend the wire in its 

 endeavours to pass round it. Hence it appears, that however 

 powerful the action of an electric current may be upon a magnet, 

 the latter has no tendency, by reaction, to diminish or increase 

 the intensity of the former — a fact which, though of a negative 

 kind, appears to me to be of some importance. — M. F. . , 



5. Electric Powers of Oxalate of Lime. — Some oxalate of lime, 

 obtained by precipitation, when well-washed, was dried in a 

 Wedgewood's basin at a temperature approaching 300°, until so 

 dry as not to render a cold glass plate, placed over it, dim. Being 

 then stirred with a platina spatula, it in a few moments, by fric- 

 tion against the metal, became so strongly electrical, that it 

 could not be collected together, but flew about the dish whenever 

 it v/as moved, and over its sides into the sand-bath. It required 

 some little stirring before the particles of the powder were all of 

 them sufficiently electrical to produce this effect. It was found 

 to take place either in porcelain, glass, or metal basins, and with 

 porcelain, glass, or metal stirrers ; and when well excited, the 

 electrified particles were attracted on the approach of all bodies, 

 and when shaken in small quantity on to the cap of a gold leaf 

 electrometer, would make the leaves diverge 2 or 3 inches. The 

 effect was not due to temperature, for when cooled out of the 



