148 BENJ. PIKE'S, JR., DESCRIPTIVE CATALOGUE. 



a bent lever, having holes at the distance of one inch apart 

 in both arms, and supported on a brass pillar, near which is 

 placed another brass pillar, on the upper part of which 

 there is a frame with sliding pulley, that can be set at any 

 height required for supporting the cord from the arm of 

 the bent lever. 



Fig. 154. 



The Inclined Plane. (Fig. 154, as above.) This con- 

 sists of two flat pieces of mahogany, about twelve inches 

 long and five inches wide, movable on a joint at one end, 

 and having a graduated semicircular arch divided into de- 

 grees, and numbered from to 90? both ways, and having 

 a clamp, spring, and milled-head screw, to fasten it at any 

 angle desired ; at the other end of the plane is fixed a 

 pulley. A small carriage rolling on three wheels, and of a 

 size to move conveniently on the inclined plane, and weigh- 

 ing exactly four ounces, is used for showing the power gained, 

 being attached to a silk cord, which is passed over the 

 pulley, and the weight attached to the end ; if the length 

 of the inclined plane be twice its elevation, two ounces will 

 balance the carriage weighing four ounces, and the smallest 

 weight added to it will draw it up. 



The Wedge. (Fig. 155.) ^ 155 - 



This is usually formed 



of two equally inclined 



surfaces, hinged together 



at the base, and when 



open forming two inclined 



planes, and when closed, a wedge ; is usually made of 



mahogany, about eight inches long. The principal use of 



the wedge consists in its being urged by the stroke of a 



