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[THE ELECTRICIAN.]




A CURRENT METER.


We give a description of a meter we made in June, 1883. You will find
a cross section of the meter and also a printed dial we had made at
the time. We called it an ampere register, but no doubt we would give
it a better name to-day. The meter consisted of a glass tube, _c_,
both ends of which were fitted into two bent pieces of piping, D and
F, as shown. Through these bent tubes, D and F, passed the wires, a
and _b_, which were connected to the binding posts, A and B. The part
of the wire where it passed into the tubes was well insulated. At the
ends, _a'_ and _b'_, was connected the coil, R, which consisted simply
of a few turns of copper wire whose diameter was less than the leading
wires, _a_ and _b_. To the tube, D, was attached a square tube, E,
which had a little opening at the top so as to permit a small
undershot wheel, I, to revolve freely. This undershot wheel was well
pivoted and constructed very light. To the axis of this wheel was
connected another system of wheels with indicators, as shown, J. Now
the tubes, E and F, were connected to a reservoir, G. This reservoir
consisted of a square tank, in the inside of which were soldered in an
alternating manner square sheets of copper as shown in the drawing,
_g_ _g'_ _g''_ _g'''_ ... These sheets acted as diffusers. These