POLYGON n.
ing many angles. Polygon of forces (Mech.), a polygonal figure, the sides of which, taken successively, represent, in length and direction, several forces acting simultaneously upon one point, so that the side necessary to complete the figure represents the resultant of those forces. Cf. Parallelogram of forces, under…
RADIUM n.
from a disintegration of the atom. This breaking up occurs in at least seven stages; the successive main products have been studied and are called radium emanation or exradio, radium A, radium B, radium C, etc. (The emanation is a heavy gas, the later products are solids.) These products are regarded as unstable eleme…