Editing Electrometer (section)

=== Early quadrant electrometer ===
[[File:Early Quadrant Electrometer.png|thumb|upright=0.5|Early quadrant electrometer.]]

While the term "quadrant electrometer" eventually referred to Kelvin's version, this term was first used to describe a simpler device. Its body consists of an upright stem of wood affixed to a semicircle of ivory with angle markings. A light cork ball hangs by a string from a pivot at the center of the semicircle and makes contact with the stem. When the instrument is placed upon a charged body, the stem and ball become charged and repel each other. The amount of repulsion is quantified by reading the angle between the string and the stem off the semicircle, though the measured angle is not in direct proportion to the charge.<ref>{{cite book|last=Draper|first=John William|title=A textbook on chemistry|year=1861|publisher=Harper and sons|location=New York|page=[https://archive.org/details/bub_gb_HKwS7QDh5eMC/page/n133 119]|url=https://archive.org/details/bub_gb_HKwS7QDh5eMC}}</ref> Early inventors included William Henley (1770) and [[Horace-Bénédict de Saussure]].<ref name=Baigrie>{{cite book|last=Baigrie|first=Brian |title=Electricity and magnetism: A historical perspective|year=2007|publisher=Greenwood Press|location=Westport, CT|page=33}}</ref>