CHAPTER VIII. Page 136

The subject of rotatory motion continued--A ball, by having a peculiar spinning motion imparted to it, may be made to stop short, or to retrograde, though it meets not with any apparent obstacle--The rectilinear path of a spherical body influenced by its rotatory motion--Bilboquet, or cup and ball--The joint forces which enable the balancer to throw up and catch his balls on the full gallop--The hoop--The centre of percussion--The whip and peg-top--Historical notices--The power by which the top is enabled to sustain its vertical position during the act of spinning--The sleeping of the top explained--The force which enables it to rise from an oblique into a vertical position--Its gyration