Galuppi, BALD ASS ARE

called BURANELLO.1706-1784. Italian composer, chiefly of operas; chapel master at St. Mark's, Venice, director of the Conservatorio degl' Incurabili, and conductor of the Imperial Opera in St. Petersburg 1765-68. IMG:content-0212.jpg:[merged small][graphic] gent galvanometer, or tangent compa , the plane of the coil is parallel with that of the meridian during the experiment, and the current strength is given by the formula C tan a ; Hr 2πη in which H is the horizontal component of the earth's magnetic force, r the mean radius of the coil, n the number of turns, and a the angle of deflection. Hr The co-efficient is called 2πη the reduction factor of the galvanometer, usually de Modified Thomson Galvanometer. 2 πη r noted by k. The galvanometer constant is denoted by or it may be defined as the strength of the magnetic field at the center of a coil due to a unit current flowing through it. If the coil be turned about a vertical axis till its plane is coincident with that of the deflected needle, C-k sin a , and the instrument is known as the sine galvanometer. If a tangent galvanometer be constructed with a short, heavy needle, and if a very brief current be pa ed through the coil, the needle will receive an impulse causing it to swing through a maximum angle a . When used thus the instrument is termed a ballistic galvanometer, and the quantity of electricity which produced 2H T a the throw a is given by the equation Q=.= sin 2, in which Tis the time of a complete oscillation of the needle and Gis the galvanometer constant. The Thomson galvanometer is a very delicate and sensitive instrument. The needle is very light and is delicately suspended in the center of a circular coil of wire. To the needle a small mirror is attached, and by watching the reflection of a beam of light upon a scale, any motion of the needle may be detected. Galvanometer Constant. See GALVANOMETER. Galvanoplasty. See ELECTROMETALLURGY.