. An encyclopaedia of architecture, historical, theoretical, & practical. New ed., rev., portions rewritten, and with additions by Wyatt Papworth. or THE WEDGE. 1321. The wedge is a body in the form of a halfrectangular prism, in practice usually of wood ormetal. AF or BG (fg. 559.) is the breadth ofits back, CE its height, CG, CB its sides, and itsend, GBC, is the terminating surface of two equallyinclined planes GCE, BCE. 1322. When a wedge is in equilibrio, the poweracting on the hack is to the force acting at rightangles to either side as the breadtli of the backAB (Jig. 560.) is to the le
. An encyclopaedia of architecture, historical, theoretical, & practical. New ed., rev., portions rewritten, and with additions by Wyatt Papworth. or THE WEDGE. 1321. The wedge is a body in the form of a halfrectangular prism, in practice usually of wood ormetal. AF or BG (fg. 559.) is the breadth ofits back, CE its height, CG, CB its sides, and itsend, GBC, is the terminating surface of two equallyinclined planes GCE, BCE. 1322. When a wedge is in equilibrio, the poweracting on the hack is to the force acting at rightangles to either side as the breadtli of the backAB (Jig. 560.) is to the length of the side AC orBC. For three forces which sustain each other ine(juillbrio are as the corresponding sides of a tri-angle drawn perpendicular to the directions in whichtliey act. But AB is perpendicular to the force. Chap. I. MECHANICS AND STATICS. S51 acting on tlie back to drive the wedge forward, and the sides AC, BC are perpendicularto the forces acting on them, tlu- three forces are tlierefore as A13, AC, BC. Thus, theforce on the back, its effect ])erpendiciilarly to AC, and its effect parallel to AB, are asthe three lines AB, AC, and DC, which are perpendicular to them. Hence the thinnerthe wedge the greater its effect to split any body or to overcome a resistance against thesides of the wedge. 1323. We are, however, to recollect that the resistance or the forces in question arerelative to one side only of the wedge ; for if those against both sides are to be reckoned,we can take only half the back AD, or else we must take double the line AC or DC. Intlie wedge the friction is very great, and at least equal to the force to be overcome, inas-much as it retains any position to which it is driven, whence the resistance is doubled bythe friction. But on the other hand, the wedge has considerabl
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