pith-ball

When this is tied to the end of a silk thread, we get the pith-ball electroscope, so much talked about in nearly every text-book on physics.

How Two Boys Made Their Own Electrical Apparatus Containing Complete Directions for Making All Kinds of Simple Apparatus for the Study of Elementary Electricity

Finally, before each screen there was a pith-ball electrometer.

Scientific American Supplement, No. 384, May 12, 1883 Various

This was, however, before the discovery of the electro-magnet (about 1800), or even the Galvanic battery, and it was seriously proposed to have as many wires as there were letters; each wire to have a frictional battery for generating electricity at one end of the circuit, and a pith-ball electroscope at the other.

Steam, Steel and Electricity James W. Steele

It is based upon the simultaneous working of two pith-ball electrometers, combined with the synchronous running of two clock-work movements.

Scientific American Supplement, No. 384, May 12, 1883 Various

Henley's pith-ball electroscope was his recording instrument.

The Catholic Encyclopedia, Volume 16 [Supplement] 1840-1916 1913

A pith-ball touched by glass excited by silk repels a pith-ball touched by silk excited by metals.

The World's Greatest Books — Volume 15 — Science Various 1909

If, however, we attach a glass handle to the rod and hold it by that whilst rubbing it, the electricity cannot then escape to the earth, and the brass rod will attract the pith-ball.

The Story of Electricity John Munro 1889

Lomond, of Paris, devised a telegraph with only one wire; the signals to be read by the peculiar movements of an attracted pith-ball, and Arthur Young witnessed his plan in action, as recorded in his diary.

Heroes of the Telegraph John Munro 1889

It consisted of a prolonged trilling or fluctuating movement called _i'i_, in which the voice went up and down in a weaving manner, touching the main note that formed the framework of the melody, then springing away from it for some short interval -- a half of a step, or even some shorter interval -- like an electrified pith-ball, only to return and then spring away again and again until the impulse ceased.

Unwritten Literature of Hawaii The Sacred Songs of the Hula Nathaniel Bright Emerson 1877

They become, in truth, like the pith-ball, in its approach to the electrified cylinder, the more fiercely repelled, the nearer the contact.

The Young Maiden 1847