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Evans, Oliver

(Encyclopedia)Evans, Oliver, 1755–1819, American inventor, b. near Newport, Del. He joined his brothers in a flour-milling business in Wilmington, and after studying similar earlier devices, he developed, install...

flint, mineral

(Encyclopedia)flint, variety of quartz that commonly occurs in rounded nodules and whose crystal structure is not visible to the naked eye. Flint is dark gray, smoky brown, or black in color; pale gray flint is cal...

amphictyony

(Encyclopedia)amphictyony ămfĭkˈtēōˌnē, –ŏˌnē, –ənēˌ [key], in ancient Greece, a league connected with maintaining a temple or shrine. There were a number of these, but by far the most important wa...

homogenization

(Encyclopedia)homogenization həmŏjˌənəzāˈshən [key], process in which a mixture is made uniform throughout. Generally this procedure involves reducing the size of the particles of one component of the mixtu...

electrolyte

(Encyclopedia)electrolyte ĭlĕkˈtrəlītˌ [key], electrical conductor in which current is carried by ions rather than by free electrons (as in a metal). Electrolytes include water solutions of acids, bases, or s...

harpoon

(Encyclopedia)harpoon härpo͞onˈ [key], weapon used for spearing whales and large fish. The early type was a flat triangular piece of metal with barbed edges and a socket for attaching a wooden handle, to the end...

Hasan

(Encyclopedia)Hasan häsänˈ [key], c.625–c.669; son of Ali and Fatima (daughter of Muhammad the Prophet). When Ali was killed in 661, Hasan became caliph, but he was not strong enough to withstand the threat of...

butane

(Encyclopedia)butane byo͞oˈtān [key], C4H10, gaseous alkane, a hydrocarbon that is obtained from natural gas or by refining petroleum. It can be liquefied at room temperature by compression. There are two struct...

plywood

(Encyclopedia)plywood, manufactured board composed of an odd number of thin sheets of wood glued together under pressure with grains of the successive layers at right angles. Laminated wood differs from plywood in ...

vomiting

(Encyclopedia)vomiting, ejection of food and other matter from the stomach through the mouth, often preceded by nausea. The process is initiated by stimulation of the vomiting center of the brain by nerve impulses ...