Electrical discharge machining (debris) to be carried away and the insulating properties of the dielectric to be restored. Adding new liquid dielectric in the inter-electrode volume is commonly referred to as "flushing." Also, after a current flow, the difference of potential between the electrodes is restored to what it was before the breakdown, so that a new liquid dielectric breakdown can occur. The erosive effect of electrical discharges was first noted in 1770 by English physicist Joseph Priestley. Two Russian scientists, B. R. Lazarenko and N. I. Lazarenko, were tasked in 1943 to investigate ways of preventing the erosion of tungsten electrical contacts
Conventional electrical unit in this way, and as such, represent a significant step towards using "natural" fundamental physics for practical measurement purposes. However, the conventional electrical units are unlike other systems of natural units in that some physical constants are not set to unity but rather set to fixed numerical values that are very close (but not precisely the same) to those in the common SI system of units. Four significant steps were taken in the last half century to increase the precision and utility of measurement units. In 1967 the Thirteenth General Conference on Weights and Measures (CGPM) defined the second of