from The American Heritage® Dictionary of the English Language, 4th Edition
- n. An instrument used to detect the presence, sign, and in some configurations the magnitude of an electric charge by the mutual attraction or repulsion of metal foils or pith balls.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. a simple device that detects the presence of an electric charge by the mutual repulsion of metal foils or pith balls
from the GNU version of the Collaborative International Dictionary of English
- n. An instrument for detecting the presence of electricity, or changes in the electric state of bodies, or the species of electricity present, as by means of pith balls, and the like.
from The Century Dictionary and Cyclopedia
- n. An instrument for observing or detecting the existence of free electricity, and, in general, for determining its kind.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. measuring instrument that detects electric charge; two gold leaves diverge owing to repulsion of charges with like sign
It was found that, if the medium held her fingers at a distance of an inch or so from the knob of the electroscope, some form of energy, apparently _radio-active_ in character, issued from her fingers, and _gradually discharged the electroscope_.
By the side of gold leaf electroscopes we see a feather electroscope, which is fastened to its support by means of a silken thread.
The spectroscope will detect a quantity of matter four million times smaller even than this; and the electroscope is a million times still more sensitive than the spectroscope.
The leaves of the electroscope were wide apart, while the inked line on the automatically revolving drum rose steadily, indicating the continued increase of cosmic rays.
The next instant Pat beheld drum, electroscope, everything within his range of vision, swim before his eyes in a distorting heat haze, while at the same time the air about him became like the stifling breath of a furnace.
Pat looked at his electroscope, and saw that it indicated a noticeable increase in the presence of cosmic rays.
He turned to the electroscope and its revolving drum; one of the most important pieces of apparatus on board, so far as the purpose of the expedition was concerned.
He's playing an electroscope blues like a hurricane,
Despite their wide usage, instruments such as the gold leaf electroscope and the spinthariscope designed by William Crookes were not accurate and precise enough to be employed for the measurement of uranium rays.
When it turned out that one of his colleagues who had worked with radioactive substances for several months was able to discharge an electroscope by exhaling, Rutherford expressed his delight.