telegraph repeater

Date1890-1920

Inventory Number1997-1-0615

ClassificationTelegraph Relay

Subject

Maker American

User Department of Physics, Harvard University founded 1884

Cultural Region

Dimensions8.6 × 17 × 9.2 cm (3 3/8 × 6 11/16 × 3 5/8 in.)

Material

DescriptionTelegraph repeater mounted on a rectangular wooden base, the wooden base sitting on an additional black metal base. There are two binding posts at the back of the base. In front of the posts are two metal cylinders (an electromagnet) connected in the back by a metal bar. A metal rod extends up from between the two cylinders and curves over and down, forming a u-shape. There are adjustment knobs on either side of the u-shape. A thin piece of metal, which is narrow at the top and wide at the bottom, extends from the center of the u-shape down to the front of the magnet. A spring extends from the thin piece of metal to a rod on top of a binding post at the front of the base. There is another binding post beside it and one behind it.

A blue triangle is painted on the corner of the wooden base and a "10" is carved on the metal base. The triangle means it was used in the department of physics at Harvard for didactic purposes.

Signedunsigned

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."

ProvenanceFrom the Department of Physics, Harvard University.