This galvanometer was used by
telegraph linesmen to check the viability
of the line. Although it is in a somewhat
distressed state, it is fascinating in that it is
dated 1859, which is stamped above
No 1 on the door. This would have been
covered by a missing plaque. The
decorated compass card is marked
80 - 0 - 80. Either side of this there are
two flat springs which enable the glass
cover to be slid out. There are three
brass framed apertures, one on the left
side and two on the right of the instrument.
Opening the door reveals a shelf, stamped
1223, with a space below for a battery.
The coils are enclosed in a lacquered
brass cowl, which, in some of the
photographs, has been removed.
The magnetic needle is mounted between
these two coils, an arrangement devised
about 1850 by Hermann von Helmholtz
(1821-1894), the attached pointer moving
over the paper scale.
Height of box 6.5 inches (16cms),
diameter of scale 2.7 inches (67mm).
Probably Italian, dated 1859.
The condition is reflected in the
Ticket Price, £170. Email me here.
