"A fixed pulley is one whose block is not movable. In this case, if the weight W be lifted by pulling down P, the other end of the cord W will evidently move the same distance upwards that P moves downwards; hence, P must equal W." — Hallock, 1905

Fixed Pulley

"A fixed pulley is one whose block is not movable. In this case, if the weight W be lifted by pulling…

"Grease the edges to make more sure of a tight joint, fit the hemispheres to each other, and exhaust the air with a pump. Close the stopcock, remove the hemispheres from the pump, attach the second handle, and, holding the hemispheres in different positions, try to pull them apart. When you are sure that the pressure that holds them together is exerted inall directions, place them under the receiver of the air pump, and exhaust the air from around them. The pressure seems to be removed, for the hemispheres fall apart of their own weight." -Avery 1895

Magdeburg Hemispheres

"Grease the edges to make more sure of a tight joint, fit the hemispheres to each other, and exhaust…

"It is worthy of note that, owing to the oblique direction in which the muscles are commonly inserted into the bones, much of their force is lost so far as producing movement is concerned. Suppose the log of wood in the diagram to be raised by pulling on the rope in the direction a; it is clear at first that the rope will act at a great disadvantage; most of the pull transmitted by it will be exerted against the pivot on which the log hinges, and only a small fraction be available for elevating the latter. But the more the log is lifted, as for example into the position indicated by the dotted lines, the more useful will be the direction of the pull, and the more of it will be spend on the log and the less lost unavailingly in merely increasing the pressure at the hinge." —Martin, 1917

Oblique Pull

"It is worthy of note that, owing to the oblique direction in which the muscles are commonly inserted…

A wrench with two serrated jaws, one adjustable, for gripping and turning pipe.

Adjustable Pipe Wrench

A wrench with two serrated jaws, one adjustable, for gripping and turning pipe.

"Diagram illustrating the disadvantage of an oblique pull." — Martin, 1917

Oblique pull

"Diagram illustrating the disadvantage of an oblique pull." — Martin, 1917

The starving dog, Curtois pulling his leash angrily after Reynard the Fox stole his pudding.

Reynard the Fox: Curtois' Complaint

The starving dog, Curtois pulling his leash angrily after Reynard the Fox stole his pudding.

"Tenacity is that property of matter by virtue of which some bodies resist a force tending to pull their particles asunder Its measure is the ratio between the breaking weight and the area of the cross section of the body broken. It varies with different substances, with the form of the body, with the temperature, and with the duration of the pull." -Avery 1895

Testing for Tenacity

"Tenacity is that property of matter by virtue of which some bodies resist a force tending to pull their…

An illustration of a unicorn pulling a cart.

Unicorns Pulling Cart

An illustration of a unicorn pulling a cart.

Any of various hand or power tools, often having fixed or adjustable jaws, used for gripping, turning, or twisting objects such as nuts, bolts, or pipes.

Pipe Wrench

Any of various hand or power tools, often having fixed or adjustable jaws, used for gripping, turning,…