Early work on electricity. Johann Winkler (1703-1770) improved the construction of the electric generator by using a leather cushion pad held against the globe by adjustable springs, rather than the palm of the hand, and made a further improvement by having the globe rotated by a cord connected to a foot treadle through an elastic rod, thereby releasing both hands. With these improvements he was able to rotate the globe of his machine as fast as 680 turns per minute and produced much brighter and stronger discharges. He also expanded earlier displays and attempted to determine the speed of the movement of electricity, concluding that no interval of time could be observed. The first part of his book describes the properties and causes of electric phenomena; the second investigates the quality of electric matter and electric fire. The essay by the German mining engineer J.S. von Waitz (1698-1777), who wrote two other essays in Dutch and one in French on the subject, won in 1744 the price at the Berlin Academy for the best dissertation on the subject of electricity.
With library stamp on half-title, ownership's inscriptions on the title-page and dedication, one plate slightly waterstained, and a few wormholes. Binding with slightly rubbed sides. Very good copy. Ad. 1: Cat. Wheeler Gift 313 b; cf: Bierens de Haan 5343 and 5344 (ed. 1745 and 1746); ad 2: cf: Bierens de Haan 5239; Poggendorff 1243.