﻿Magnetism and Static Electricity* 301 



attract it at a greater distance than it previously did. The wire 

 was pointed. 



The writer next insulated the horseshoe-magnet, and endea- 

 voured to make evident a reduction of magnetic attractive power 

 when it was itself charged with electricity. 



Pieces of soft iron wire one and a half inch in length were 

 attached by attraction successively to one pole till the point at 

 which the magnet ceased to attract was nearly reached. Elec- 

 tricity was then passed into the magnet ; and during the charging 

 process the last piece of wire in the magnetic chain first vibrated 

 strongly, and finally fell off. When two pieces of iron wire were 

 hung side by side at the end of the chain, their divergence wasv 

 great whilst the magnet was receiving electricity ; and if the at- 

 tracting force was feeble, one or the other of the pieces dropped off. 



Another mode in which the experiment was performed was by 

 elongating either pole with a piece of soft iron two inches long 

 and held by magnetic attraction, to the end of this, again, pieces 

 of soft iron wire about one inch in length, and then partially 

 closing the magnetic circuit by a stout nail laid across the limbs 

 of the magnet : by moving the latter nearer to or further from 

 the poles the force holding the wires at the end of the elongated 

 pole could be brought within limits that enabled the feeble elec- 

 tricity employed to contend with it. Under these circumstances, 

 whenever the magnet was charged with electricity, one or more 

 wires immediately fell off. 



After repeating the experiment a few times with the same 

 wires, the same ends being attached to the same pole each time, 

 it was found that they had become to a slight extent magnetic, 

 the magnetism according in polarity with the law of magnetiza- 

 tion by contact ; so that the electricity had to overcome an ad- 

 ditional attraction, which it probably itself assisted to create, in 

 addition to that previously existing. A powerful electrical ma- 

 chine would probably enable an experimenter to demonstrate 

 these effects more fully. 



He then placed the magnet on the upper side of a glass plate, 

 the lower side of which, except for about two inches round the 

 edges, was coated with tinfoil, and had a good earth connexion, 

 and, throwing some fine iron-filings on the poles, charged the 

 system. Whilst doing this a number of filings were thrown off 

 from the poles and dispersed, the filaments of adhering particles 

 first rapidly vibrating and oscillating, each filament exercising a 

 greater degree of repulsion on its neighbour than it previously 

 did, and finally jumping off in small masses, which instantly dis- 

 sipated as soon as they got beyond the scope of the magnet's 

 greatest intensity. On making contact between the tinfoil and 

 magnet, the filaments returned to their original degree of diver- 



