Technical instrument - France - 1850-1900 - an electronic recorder

an electromagnetic drum recorder, more precisely a low-current electrical recorder, used between the end of the 19th century and the first third of the 20th century.
It belongs to the family of instruments known as continuous-recorders with a galvanometer and a pen.
sometimes called chart recorders or electric chronographic recorders
The heart of the device is a sensitive galvanometer; a coil (visible in copper) responds to the passage of a current. The angular movement is transmitted to a hinged arm; this arm moves a metal nib or stylet. This stylet inscribes a trace on graph paper wound around a rotating drum.

The drum is driven by a clockwork mechanism.

This type of device was used for:

Telegraphy (measurement of line currents)

Physics Laboratories

Weather stations (electrometers, sensors)

Early Industrial Measures

Medical research (physiological currents, adapted versions)

This is clearly a scientific and technical instrument, not a domestic one.
Solid wood case (often walnut or light oak), glass-front façade. Enables reading without mechanical disturbance, protects against dust and air fluctuations.

Upper metal handle:

transport

field or laboratory instrumentation

2. Mechanics and finishes

Internal parts in:

machined brass

blued steel

copper

Fully mechanical construction, without modern electronic components.
Dating: 1890 – 1925



Case intact, with no major cracks.

The glass is present and clear.

Visibly complete mechanism
Drum and arm in place
Old paper still present (rare)
Points to monitor
Natural oxidation of metals
Lubrication of the watch movement
Galvanometer sensitivity to be checked