A group of boys moving wooden boxes and barrels.

Boys with Boxes

A group of boys moving wooden boxes and barrels.

"A horse- or steam-power machine for digging, moving, or transporting loose gravel, sand, or soil." -Whitney, 1911

Excavator

"A horse- or steam-power machine for digging, moving, or transporting loose gravel, sand, or soil."…

Illustration showing a line that moves so that its ends constantly touch two fixed lines which are perpendicular to each other. Locus of the midpoint.

Circle Made by Ends of a Line Touching Two Fixed Lines Perpendicular to Each Other

Illustration showing a line that moves so that its ends constantly touch two fixed lines which are perpendicular…

An illustration of men in a barn moving hay with pitch forks.

Men in Barn

An illustration of men in a barn moving hay with pitch forks.