(Encyclopedia) John Henry, legendary African American famous for his strength, celebrated in ballads and tales. In the most popular version of the story, John Henry tries to outwork a steam drill…
(Encyclopedia) StavropolStavropolstäˈvrəpəl [key], city (1989 pop. 318,000), capital of Stavropol Territory, S European Russia, on the Stavropol Plateau. It has machine-tool, wool, leather, grain…
(Encyclopedia) pillbox, small, low fortification that houses machine guns and antitank weapons. Similar to a blockhouse, it is usually made of concrete, steel, logs, or filled sandbags. Pillboxes…
(Encyclopedia) Carlson, Chester Floyd, 1906–68, American inventor; b. Seattle, Wash. A patent lawyer, he invented (1938) xerography, a method of electrostatic printing. For the next two decades he…
(Encyclopedia) boring mill, machine tool used to increase the size of a hole previously made in a workpiece, usually with the purpose of obtaining a required degree of finish and accuracy in the…
(Encyclopedia) reaper, early farm machine drawn by draft animals or tractor and used to harvest grain. Its historical predecessors were the sickle and the cradle scythe, which are still used in some…
(Encyclopedia) screw, simple machine consisting essentially of a solid cylinder, usually of metal, around which an inclined plane winds spirally, either clockwise or counterclockwise. It is used to…
HOW CAN SOLIDS BE SEPARATED? HOW DOES DISTILLATION WORK? HOW ARE GASES SEPARATED? FILTRATIONFIND OUT MOREHow do we extract salt from seawater? Methods for separating a mixture depend on differences…
HARDWARESOFTWAREFIND OUT MOREA computer is an electronic machine that obeys instructions telling it how to present information in a more useful form. Its HARDWARE is the actual machine, including…
