[Oxygen], a colourless, inodorous gas which constitutes one-fifth in volume of the atmosphere, and which, in combination with hydrogen, forms water. It is the most widely diffused of all the elementary bodies, and an essential support to everything possessed of life.
[Oyer and Terminer], an English Court Commission to hear and determine special causes.
[Ozone], is an allotropic form of oxygen, from which it can be developed by electricity, and into which it can be resolved by heat, present in small quantities in the atmosphere, and possessing strong oxidising properties.
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[Pache, Jean], Swiss adventurer, who became Mayor of Paris, and even Minister of War during the French Revolution, "the sleek Tartuffe that he was," is credited with the authorship of the famous revolutionary motto, Liberty, Equality, and Fraternity, or Death (1746-1823).
[Pachomius, St.], an Egyptian hermit, the founder of conventual monachism, who established the first institution of the kind at Tabenna, an island in the Nile; he also established the first nunnery under his sister (292-348). Festival, May 14.
[Pachydermata], hoofed animals with thick skins and non-ruminant, such as the elephant and the hog.
[Pacific Ocean], the largest sheet of water on the globe, occupies a third of its whole surface, as much as all the land put together. It is a wide oval in shape, lying between Australia and Asia on the W., and North and South America on the E. Except from Asia it receives no large rivers. On its American shores the Gulf of California is the only considerable indentation; the Okhotsk, Japanese, Yellow, and Chinese Seas, on the Asiatic coast, are rather wide bays shut in by islands than inland seas. Its innumerable islands are the chief feature of the Pacific Ocean. The continental islands include the Aleutian, Kurile, Japan, and Philippine Islands, and the archipelago between the Malay Peninsula and Australia; the Oceanic Islands include countless groups, volcanic and coral, chiefly in the southern hemisphere, between the Sandwich Islands and New Zealand. Commerce on the Pacific Ocean is only beginning, but will increase vastly with the extension of the United States westward, the colonisation of Australia, and the opening of Chinese and Japanese ports. San Francisco and Valparaiso on the E., Hong-Kong and Sydney on the W., are just now the chief centres of trade.
[Packhard], distinguished American entymologist and naturalist, born in Maine; his classification of insects is accepted; b. 1839.