372 Researches in Magnetic Electricity. 
terminations of the small wire, d, J, the terminations of the large 
_wires. 1, is a wooden strap, which, with a binding-screw, secures 
the magnet to the wooden block k&.  s is a brass strap, to hold 
firmly the poles of the magnet. e is the armature of soft iron, 
which, with the small brass pulley, is fitted firmly to the shaft. 
o, the multiplying wheel. 2, is the break-piece, which is merely 
a copper ferule dissected, and filled up with wood or ivory, as 
represented by the black spaces. é@, one of the magnet wires bent 
up, plays upon the whole portion of the ferule ; and m, one of the 
battery wires, plays upon the break-piece. "The other battery 
wire is to be connected with the mercury cup d. Adjust now the 
break-piece, n, or the copper wire, m, so that the circuit shall be 
broken at the time or immediately after the armature leaves the 
magnet, and turn the multiplying wheel «. The sparks and 
shocks thus produced, will be found far greater than when the 
circuit is broken while the armature is apprdaching. The break- 
piece is readily adjusted, so that the armature revolves of itself 
- with great rapidity ; but in this case also, the sparks and shocks* 
are at once diminished, as the source of magnetism must be cut 
off before the armature arrives at its equilibrium. With things 
thus arranged, connect the two ends of the small wire 4, c. (‘This 
wire is insulated, and entirely independent of the large wire.) 
The revolution of the armature is now suddenly stopped. The 
flowing of the secondary current after the galvanic is broken, 
keeps up or prolongs the power of the magnet so as to retain the 
armature. Asa proof of this, set the spina and break-piece so 
that the magnetic power shall be cut off, some time before the 
armature arrives at equilibrium. It revolves of course slowly. 
Connect now the ends of the small wire 8, c, and it immediately 
revolves with rapidity, the prolongation of magnetism by the 
secondary, contributing now to the motion of the bar. Here then 
the secondary becomes a new source of magnetic power. This 
instrument, when the armature is revolved mechanically, affords 
a shock from 6, c, both when the circuit is completed and broken. 
The sparks are exceedingly brilliant, and the shocks so powerful 
that they are sometimes felt by the bystanders through the floor. 
The light from charcoal points is intense. It decomposes pure 
water, and charges the Leyden jar. But its most remarkable and 
novel SUE Reese is that of giving a slight shock without breaking 
a 
“The shocks are taken from the eups 6, = 
