telegraph repeater

Date1890-1920

Inventory Number1997-1-0610

ClassificationTelegraph Relay

Subject

Maker J. H. Bunnell & Company 1878-present

Cultural Region

Place of Origin

Dimensions9.1 × 20.6 × 12.2 cm (3 9/16 × 8 1/8 × 4 13/16 in.)

Material

DescriptionTelegraph repeater mounted on a rectangular wooden base, the wooden base sitting on an additional black metal base. Two black cylinders (an electromagnet) sit in the middle of the base, connected in the back by a black metal plate. A thick coil extends from the back of this plate through to a metal knob and an adjustment dial. A u-shaped metal rod extends up from between the cylinders and has a double adjustment knob on the end. A thin piece of metal, narrow at the top and wide at the bottom, extends from the center of the u-shape to the front of the cylinders. A spring is attached to a hook on the thin metal plate and extends to an adjustment knob on the front of the base. Two binding posts sit on the front right of the base and two more on either side of the knob at the back of the base.

Signedon base: J. H. BUNNELL & CO. NY

Inscribedon base: 250 OHMS

FunctionThe telegraph repeater was used to faciliate the sending of messages over long distances.

According to George B. Prescott's History, Theory and Practice of the Electric Telegraph, available here:

"The repeater is an apparatus for the purpose of duplicating from one electric circuit to another the breaks and completions received from the transmitting station, for the purpose of renewing the power lost by the escape of the electric fluid into the earth through imperfect insulation."