telegraph sounder

Date1910-1920

Inventory Number1997-1-0575

ClassificationTelegraph Receiver

Subject

Maker Western Electric Company 1869 - 1995

User Department of Physics, Harvard University founded 1884

Cultural Region

Place of Origin

Dimensions9.4 × 14 × 7.6 cm (3 11/16 × 5 1/2 × 3 in.)

Material

DescriptionTelegraph sounder, mounted on a black, rectangular metal base. At the back of the base is a strip of metal with two bolts in it, a "+" printed to the left of the strip and a "-" printed to the right. In front for the strip is the main apparatus, all of which is sitting on a brass, rectangular plate. At the back of the brass plate is a thick piece of black metal, extending up into an arch. It is bolted to a black piece of metal, which is in turn sitting on the brass plate. There is an "N" printed on one end of the bar. In front of the black arch is a smaller brass arch with an adjustment dial on top. A metal bar runs from one side of the arch to the other and through a silver metal bar. The silver metal bar extends from the arch, under a black metal plate connecting two black metal coils (an electromagnet), to the inside of a piece of brass forming the border of a rectangle. One screw with an adjustment dial on top runs through the top of the piece of brass into the metal bar, and another screw runs just through the metal bar.

Signedon metal bar: WESTERN ELECTRIC / MADE IN USA

Inscribedon base: 1050 OHMS / 7 A SOUNDER

FunctionThis instrument is used for receiving telegraphic messages from distant locations. When a current runs through the battery, it activates the magnet, which in turn exerts a force on the silver metal bar. The current is turned on and off by the operator of a signaling apparatus connected to the receiving apparatus by wires. The bar is attracted to the magnet when the current is on, and returns to its resting position when the current is off, making a sound when it hits the brass above and below it. In this manner, a Morse code message can be sounded.

ProvenanceFrom the Department of Physics, Lyman Laboratory, Harvard University.