"Represents in diagram the arrangement of the battery, resistance, and galvanometer. There are two keys, K and K, , placed in the circuit whose uses will be subsequently explained for the present, the diagram will be considered as if these keys did not exist, and as if the current flowed permanently through. the circuits as is indicated by the arrow-heads." (Britannica, 1891)

Arrangement of Battery, Resistance, and Galvanometer

"Represents in diagram the arrangement of the battery, resistance, and galvanometer. There are two keys,…

A wet-cell battery composed of zinc in a copper sulfate solution.

Daniell's Battery

A wet-cell battery composed of zinc in a copper sulfate solution.

An insulator is a material that resists the flow of electric current. An insulating material has atoms with tightly bonded valence electrons. These materials are used in parts of electrical equipment, as insulation. The term is also used to refer to insulating supports that attach electric power transmission wires to utility poles. Some materials such as glass, paper, or Teflon are very good electrical insulators.

Electric Wire Insulator

An insulator is a material that resists the flow of electric current. An insulating material has atoms…

The magnet produced by an electric current is called an electro-magnet.

Electro-Magnet

The magnet produced by an electric current is called an electro-magnet.

"A magnet which owes its magnetic properties to the inductive action of an electric current." -Whitney, 1911

Electromagnet

"A magnet which owes its magnetic properties to the inductive action of an electric current." -Whitney,…

An illustration of the foster method, used to measure electric current.

Foster's Method

An illustration of the foster method, used to measure electric current.

"Astatic galvanometer, an instrument which consists of a pair of similar needles magnetized, with their poles turned opposite ways, and stiffly connected at their centers, so that both will swing together." -Whitney, 1911

Astatic Galvanometer

"Astatic galvanometer, an instrument which consists of a pair of similar needles magnetized, with their…

"The galvanometer consists of two distinct coils of wire, each having the same resistance, and having equal magnetic effects upon the needle. These coils C and C' are wound in opposite directions, as shown, and one end of each is joined to the same terminal on the frame of the galvanometer; the other ends are joined to separate terminals also situated on the frame." (Britannica, 1891)

Differential Galvanometer

"The galvanometer consists of two distinct coils of wire, each having the same resistance, and having…

An illustration of the loss of charge method.

Loss of Charge Method

An illustration of the loss of charge method.