Fluxion

[Fr., from Lat. fluzio, from fluere, to flow.] The act of flowing, or moving as a fluid. - The matter that flows. Fusion, as of metals. (Med.) A flow of blood or other humor toward any organ with greater force whau natural. (Math.) The analysis of infinitely small variable quantities, invented by Newton in 1665. Newton considered a curve as generated by the uniform motion of a point, and decomposed at every instant by the constant velocity of this point into two others, one parallel to the axis of the absci a, and the other parallel to the axis of the ordinates. These velocities are what he called | Fly'-catcher, n. One who catches flies. the fluxions of the co-ordinates; while the arbitrary ve- locity of the point which describes the curve is the flux- ion of the arc. Reciprocally, the arc described is called the fluent of the velocity with which it is described by the moving point; the corresponding absci is the flu- ent of the velocity estimated in the direction of the ab- sci , and the ordinate the fluent of the velocity of the point estimated in the direction of the ordinate. The same considerations may be extended to the areas bound- ed by curve lines, to surfaces and the volumes which they determine, to forces which give rise to motion in bodies, and to the effects which they produce. In fact, the theory is applicable to everything which forms the object of the mathematical or physico-mathematical sciences. The methods of integral and differential cal- culus, which are le complex and more trustworthy, have superseded the fluxions, although they are still employed in working out some problems. - See DIFFER-