The unit of work is that which is required to overcome a resistance of a dyne over a centimetre, and is called an Erg.
In the latitude of Paris the dyne is equal to the weight of about of a gramme, and the erg is the amount of work required to raise Ti lerof a gramme vertically through one centimetre.
The unit of mechanical force in the " centimetre, gramme, second " (C.G.S.) system of units is the dyne, which is approximately equal to 1/981 part of the weight of one gramme.
A very small sphere is said then to possess a charge of one electrostatic unit of quantity, when it repels another similar and similarly electrified body with a force of one dyne, the centres being at a distance of one centimetre, provided that the spheres are in vacuo or immersed in some insulator, the dielectric constant of which is' taken as unity.
System the unit of force is called the dyne, and the unit of work or energy the erg.
Van Dyne, Our Foreign Service (Rochester, N.Y., 1909).