Magnetic Pole. The earth has North and South magnetic poles. The south pole of a magnetic needle is attracted so it points to the north magnetic pole; and the north pole of the needle is attracted to point to the south magnetic pole. Magneto-generator. A permanent magnet and a revolving armature for generating a current. Maximum Voltage. The final voltage after charging. Molecule. Invisible particles made up of two or more atoms of different matter. An atom is a particle of one substance only. Morse Sounder. An electric instrument designed to make a clicking sound, when the armature is drawn down by a magnet. Motor-dynamo. A motor and a dynamo having their armatures connected together, whereby the motor is driven by the dynamo, so as to change the current into a different voltage and amperage. Motor-transformer. A motor which delivers the current like a generator. Needle. A bar magnet horizontally poised on a vertical pivot point, like the needle of a mariner's compass. Negative Amber, when rubbed, produces negative electricity. Electricity. A battery has positive as well as negative electricity. Negative Element. That plate in the solution of a battery cell which is not disintegrated. Normal. The usual, or ordinary. The average. In a current the regular force required to do the work. North Pole, The term applied to the force located near Electric. the north pole of the globe, to which a permanent magnet will point if allowed to swing freely. O. Abbreviation for Ohm. Ohm. The unit of resistance. Equal to the resistance of a column of mercury one square millimeter in cross section, and 106.24 centimeters in length. Ohm's Law. It is expressed as follows: 1. The current strength is equal to the electro-motive force divided by its resistance. 2. The electro-motive force is equal to the current strength multiplied by the resistance. 3. The resistance is equal to the electro-motive force divided by the current strength. Overload. In a motor an excess of mechanical work which causes the armature to turn too slowly and produces heat. Phase. One complete oscillation. The special form of a wave at any instant, or at any interval of time. Plate, Condenser. In a static machine it is usually a plate of glass and revoluble.