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"Thomson's absolute electrometer is an adaptation of the attracted disc principle for absolute determinations. We give merely an indication of its different parts, referring to Thomson a paper for details." — Encyclopedia Britannica, 1893

Absolute Electrometer

"Thomson's absolute electrometer is an adaptation of the attracted disc principle for absolute determinations.…

"The gold leaves are gummed on the two sides of a flat piece of metal carried by a stout stem, which passes through the top of a glass shade and ends in a flat disc. By means of this disc we may convert the instrument into Volta's condensing electroscope." — Encyclopedia Britannica, 1893

Bennets Electroscope

"The gold leaves are gummed on the two sides of a flat piece of metal carried by a stout stem, which…

"Cavallo's electroscope embodies the double pendulum principle. It consists of two fine silver wires loaded with small pieces of cork or pith, and suspended inside a small glass cylinder. Through the cap which closes the cylinder passes the stout wire from which the pendulums are suspended. This wire ends in a thimble-shaped dome A, which comes down very nearly to the cap; the outside of the cap is part of the wire and covered with sealing wax, and the object of the dome is to keep moisture from the stem, so that the electroscope could be used in the open air even in rainy weather." — Encyclopedia Britannica, 1893

Cavallos Electroscope

"Cavallo's electroscope embodies the double pendulum principle. It consists of two fine silver wires…

"D is a needle, formed of light silver wire, suspended by a fine glass fiber, from a torsion head A. Below the needle is a piece of sheet metal NE, divided half through by a notch in the middle, and then bent in opposite directions on both sides of the notch, so that, when looked at end on, it appears like a Y." — Encyclopedia Britannica, 1893

Dellman's Electrometer

"D is a needle, formed of light silver wire, suspended by a fine glass fiber, from a torsion head A.…

"C is an insulated disc, over which is suspended another disc, hung from the arm of a balance, and connected with the earth. A weight w is put in a scale attached to the other arm of the balance. The insulated disc is connected with the internal armature B of a Leyden jar, whose outer armature is in connection with the suspended disc, Electricity is conveyed to B, and the quantity q measured by a small Lane's jar A, until the electric attraction at C is just sfficient to turn the balance." — Encyclopedia Britannica, 1893

Disc Electrometer

"C is an insulated disc, over which is suspended another disc, hung from the arm of a balance, and connected…

"Discharging Electroscope" — Encyclopedia Britannica, 1893

Electroscope

"Discharging Electroscope" — Encyclopedia Britannica, 1893

"The electrometer of Henley, sometimes called Henley's quadrant Henley electrometer, may be taken as the type of single pendulum electroscopes. It consists essentially of a pendulum A hinged to meter a verticle support C, which carries a vertical graduated semicircle B, by means of which the deviation of A from the vertical can be indicating the state of electrification of the prime conductors of electric machines. The stem is screwed into the conductor, and the divergence of the pendulum indicated roughly the charge." — Encyclopedia Britannica, 1893

Henleys Electrometer

"The electrometer of Henley, sometimes called Henley's quadrant Henley electrometer, may be taken as…

"Section of Thomson's Portable Electrometer." — Encyclopedia Britannica, 1893

Portable Electrometer

"Section of Thomson's Portable Electrometer." — Encyclopedia Britannica, 1893

"The sine electrometer of August, is a modification of the single pendulum electroscope, analogous in principle to Pouillet's sine compass. A is a pendulum suspended by two threads to secure motion in one plane; B is a ball fixd to the case, and connected with a suitable electrode." — Encyclopedia Britannica, 1893

Sine Electrometer

"The sine electrometer of August, is a modification of the single pendulum electroscope, analogous in…