A decimal system of units originally devised by a committee of the French Academy, which included J. L. Lagrange and P. S. Laplace, in 1791. It was based on the metre, the gram defined in terms of the mass of a cubic centimetre of water, and the second. This centimetre-gram-second system (see c.g.s. units) later gave way for scientific work to the metre-kilogram-second system (see m.k.s. units) on which SI units are based.