For measurement of small quantities of electrical charge. Reflecting mirror type model. The moving coil is suspended by a phosphor-bronze strip, which carries an optically true concave mirror. The coil can be raised or lowered or set to zero by an adjusting knurled knob at the top. A knob at the back is provided for clamping and releasing the coil. A link high resistance is provided to make the Galvanometer periodic, if desired. Levelling screws are provided for balancing the coil.