Description of a Magnetic Electrical Machine. 21 
To adjust the quantity armature and exhibit the spark. 
Fig. 4. A, the magnetic F1Q. 4. . “7 
battery ; D, the armature, Sw 
having two coils of insulated 
copper wire twenty yards 
each. Care must be taken 
that the spring separate from 
the break at the same time 
that the armature is vertical, | 
being then in a neutral posi- 
tion as respects the poles of 
the battery. 
To scintillate tron wire. 
Connect one end of a piece of iron wire with the square brass pil- 
lar, fig. 5, pressing the other end gently on the surface of the rotating 
armature, and brilliant scintillations will be obtained. This effect 
cannot be produced by any magnetic machine unless it be construct- 
ed similarly to E. M. Clarke’s ; the effect depending upon the wires 
being soldered to the armature ; whereas, in other armatures the wire 
is insulated throughout. 
