...introduced and demonstrated the proposition, that if two forces act at right angles to each other, their action, whether successive or simultaneous, will neither...work the author has treated of the six mechanical powers,—the Lever, Wheel and Axle, Pulley, Inclined Plane, Wedge, and Screw,—and has elucidated...

...plane ; therefore, if the power act in a direction parallel to the base of the cylinder, P is to w as the distance between the threads to the circumference of the cylinder ; but the weight does not usually rest on one point of the screw, but is distributed over a considerable...

...of equilibrium is, that the power shall be to the weight as the height of the plane to its base, or as the distance between the threads to the circumference of the cylinder. The screw is usually used with a lever inserted into the top of the screw. Its length is reckoned from...