202 Dr. Faraday’s Experimental Researches in Electricity. 
stood stjll.. Upon the interruption of the electric current at the 
magnet tke revulsion came on very strongly, and the block turned 
back again, passed the equatorial line, and proceeded on until it 
formed an angle of 50° or 60° on the other side; but instead of 
: Continuing to revolve in that direction as before (2315. ), it then ; 
» Teturned on its course, again passed the equatorial line, aud almost 
reached the axial position before it stood still. In fact, as a mass, 
, it vibrated .to and fro about the equatorial line. 
2688. This however is a simple result of the principles of ac- 
tion formerly developed (2329. 2336.). The revulsion is due to 
“the production of induced currents in the suspended mass during 
2 the falling of the magnetism of the electro-magnet ; and the el- 
|... fect of the action is to bring the axis of these induced currents 
ese - parallel to the axis of force in the magnetic field. Consequently, 
. if the time of the fall of magnetic force, and therefore. of the 
_/". , currents dependent thereon, be greater than the time occupied by 
the revulsion of the copper block as far as the equatorial line, any 
‘ a partes Motion of it by momentum will be counteracted by a con- 
Se an occur. before the force of the electro-magnet has ceased to fall 
poh The effect of time, both in the rising and falling 
r, has been referred to on many former occasions (2170. 
0) and as Vgty beautifully seen here. 
q° Returning to the subject of the assumed polarity of bis- 
: th, I may and ought to refer to an experiment made by Reich, 
! “wand describ ‘by Weber, * which, if I understand the instruction 
ollows: a strong horseshoe magnet is laid upon @ 
pavreri ul magnetic Beets suSpel by cocoon x 
Fe sido of it, the pole o ar, 
eae as “exactly” to counterget 
| igt,an ping a needle t td poin 
awvay pi 
es of fe ijbrseah ti J 
ar direc- 
net needfedusing it i oF a. Hay cg 
ey this is supposéd 40 ‘the om 
r the clagienatances, as at ape suc sa he 3 "* 
are away. A piece of iron in. ee of at bismuth produc 
the contrary pee of the ne eedlé. 
