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act of God

(Encyclopedia)act of God, in law, an accident caused by the operation of extraordinary natural force. The effect of ordinary natural causes (e.g., that rain will leak through a defective roof) may be foreseen and a...

Hume, David

(Encyclopedia)Hume, David hyo͞om [key], 1711–76, Scottish philosopher and historian. Educated at Edinburgh, he lived (1734–37) in France, where he finished his first philosophical work, A Treatise of Human Nat...

goatsucker

(Encyclopedia)goatsucker, common name for nocturnal or crepuscular birds of the order Caprimulgiformes, which includes the frogmouth, the oilbird, potoos, and nightjars. Goatsuckers are medium in size and are found...

Nobel Prize

(Encyclopedia)CE5 CE6 Nobel Prize, award given for outstanding achievement in physics, chemistry, physiology or medicine, peace, or literature. The awards were established by the will of Alfred Nobel, who left...

paleomagnetism

(Encyclopedia)paleomagnetism, study of the intensity and orientation of the earth's magnetic field as preserved in the magnetic orientation of certain minerals found in rocks formed throughout geologic time. Paleom...

boiling point

(Encyclopedia)boiling point, temperature at which a substance changes its state from liquid to gas. A stricter definition of boiling point is the temperature at which the liquid and vapor (gas) phases of a substanc...

disk plow

(Encyclopedia)disk plow or disk, farm implement employing a row or rows of concave circular steel disks that cut and pitch the soil in a way somewhat similar to a moldboard plow. It can be used in many situations w...

conjunction, in astronomy

(Encyclopedia)conjunction, in astronomy, alignment of two celestial bodies as seen from the earth. Conjunction of the moon and the planets is often determined by reference to the sun. When a body is in conjunction ...

cover crop

(Encyclopedia)cover crop, green temporary crop grown to prevent or reduce erosion and to improve the soil by building up its organic content. Green-manure crops, which are specifically grown for their organic conte...

circumpolar star

(Encyclopedia)circumpolar star, star whose diurnal circle lies completely above or completely below an observer's horizon. A star whose diurnal circle lies above the horizon never sets, even though it cannot be see...