from The Century Dictionary and Cyclopedia
- n. A telegraph in which the indications are given by the deflections of a magnetic needle whose normal position is parallel to a wire through which a current of electricity is passed at will by the operator.
Sorry, no etymologies found.
A tangent galvanometer, or a needle-telegraph instrument, for example, may be connected with Y and Z. 227.
Current reversers are used in connection with the needle-telegraph and many other instruments.