Bees 
ay 
252 W. A. Anthony— Electro magnetic Machine. 
wide, of very soft iron wire 3 mm. square. To prevent, as far as 
possible, the formation of induced currents in the coil itself, 
which would consume power to no purpose, the wire, while 
being wound into the coil, was drawn through a thick shellac 
varnish, which, it was thought, would to a certain extent insu- 
late the adjacent wires from each other. 
The conducting wire of the armature consists of 100 coils, 
each of 4 meters, of cotton-covered copper wire 2 mm. square. 
These coils terminate alternately on the right and left of the 
armature, and each set is connected with fifty copper strips 
which surround the axis and serve to transmit the current in 
the usual way. The two sets of coils are entirely independent 
of each other, and constitute practically two distinct arma- 
tures. The resistance of each armature as employed in the 
machine is very nearly + of an ohm. : 
he cores of the two inducing magnets are 7°5 cm. diameter, 
60 cm. long. At the middle of each is a block of cast irom 
which serves as the magnetic pole, 15 cm. wide, and embracing 
about one-third of the circumference of the armature. On 
each end of the cores is a bobbin 25 cm. long and 15 cm. 
diameter, wound with eight layers of copper wire 3°5 min. 
uare. The eight layers are not joined on the bobbins, bs 
form so many independent conductors, the terminals of whie 
are carried to a commutator on the base of the machine. The 
commutator serves to combine the wires into one continuous 
conductor having a resistance a little less than one ohm, oF 
into 4, 8 or 32 conductors in multiple are. 
The wires from the four brushes which collect the a 
from the armatures are carried to another commutator, whic 
serves to join the two armatures in series or 1n multiple eer 
with the coils of the inducing magnet in the main circuit, oF as 
ut one armature in circuit with the magnet coils, while ee 
other communicates with the terminals of the machine 
Preparations were commenced for making : corp tee aed 
to send the machine to the Centennial exhibition, and, 
preparations could not be completed in time, only a lew 
were made. rge German-silver wires were st 
measu 
rents, a tangent galyanometer was especially 
its ppatants determined. from a large number ©: 
with the copper voltameter. - iments. 
_ The tables below give some of the results of the experi. 
The observations and computations were made under oof this 
tion, principally by Mr. M. M. Garver, now a graduate 
