tion
or not.

With regard to the dynamo, the spindle is of steel, 18 feet long, with
three bearings, one being placed on either side of the driving pulley.
The diameter is 7 inches in the bearings and 10 inches in the part
within the core. This part in the original forgings was 14 inches in
diameter, and was planed longitudinally, so as to leave four
projecting ribs or radial bars on which the core disks are driven,
each disk having four key ways corresponding to these ribs. There are
about 900 of these disks, the external diameter being 20 inches and
the total length of the core 36 inches.

The armature winding consists of 128 copper bars, each 7/8 in. deep,
measured radially, by 3/8 in. wide. These bars are coupled up so as to
form thirty-two conductors only; this arrangement has been adopted to
avoid the heating from the Foucault currents, which, with 11/2 in.
conductors, would have been very considerable. The bars are coupled at
the ends of the core across a certain chord and are insulated.

The commutator is 20 inches long, and has sixty-four parts. The
current is collected by eight brushes mounted on a separate ring,
placed concentric to the commutator; and the current is led away from
these brushes by a large number of thin bands of sheet copper strapped
together into convenient groups. The field magnets are of the
horizontal double type.

As this machine is virtually a series wound machine, the magnet coils
each consist of a few turns only of forged copper bars, 11/2 in. wide by
1 in. thick, forged to fit the magnet cores.

There is no insulation other than mica wedges to keep the bars from
touching the core.

The dynamo furnishes a current of about 5,000 amperes, with an E.M.F.
of 50 to 60 volts, and three years ago was claimed to be the largest
machine, at least as regards quantity of current, in the world.

The current from the dynamos is led by copper bars to an enormous "cut
out," calculated to fuse at 8,000 amperes. This is probably one of the
largest ever designed, and consists of a framework carrying twelve
lead plates, each 31/2 in. x 1/16th in. thick. A current indicator is
inserted in the circuit consisting of a solenoid of nine turns. The
range of this indicator is such that the center circle of 360 deg.=8,000
amperes.

The electrodes consisted of a bundle of nine carbons, each 21/2 in. in
diameter, attached by casting into a head of cast iron. Each carbon
weighs 20 lb, and, when new, is a