GAZELLE
742
GENET
lessor of chemistry at the Jardin des Plantes.
One of his most important pieces of work is that in which he proves that, when gases combine with one another by volume, they do so in simple proportions. Thus two volumes of hydrogen combine with one volume of oxygen to form two volumes of water. Equally important, perhaps, is his discovery of the manner in which gases change volume or pressure when the temperature changes. For description of this, see BOYLE'S LAW.
Among his chemical investigations, perhaps his demonstrations of the nature of iodine and of hydrochloric acid are as important as any. In addition to his scientific accomplishments, he was a man of extraordinary breadth, a member of the Chamber of Deputies, widely traveled and largely acquainted with men. Gazelle. See ANTELOPE. Geary, John White, American soldier and governor of Pennsylvania, was born near
Mount Pleas-ant, Pa., Dec. 30, 1819, and died at Harris-burg, Pa., Feb. 8, 1873. Early in life he studied law, but never practiced. During the Mexican War he acted as colonel of the 2d Pennsylvania regiment, and was made first command er of the City of Mexico. In 1849 he was appointed postmaster of San Francisco, and in the following year became mayor of the city. In 1856 he was created territorial governor of Kansas. At the opening of the Civil War he raised the 28th Pennsylvania volunteers and rose to the rank of major-general. He took part in many notable engagements and was with Sherman in his march to the sea. In 1866 he became governor of Pennsylvania and held the office until his death.
Gehenna (ge-hen'd) or, in Hebrew, Valley of Hinnom, was a narrow gorge south and west of Jerusalem. Under the later Jewish kings it became a favorite place for the celebration of idolatrous rites, and when King Josiah restored the old national faith, he "defiled" the valley by covering it with human bones. After this it became the common cesspool of the city, into which its sewage was brought, to be carried off by the waters of the brook Kedron. It is also said that fires were kept constantly
GENERAL GEARY
burning here to consume the bodies of criminals, the carcasses of animals and whatever else could be burned. Among the later Jews Gehenna and Tophet came to be symbols for hell and torment.
Geijer (yi'dr), Eric Gustaf, a noted Swedish historian, was born in Wermland, Jan. 12, 1783. D'^'vting himself to the study of history, he oecame professor of that branch in the University of Upsala. He also wrote poems and political essays, and was known as a composer and musician. He died on April 23, 1847. His historical works are chiefly confined to the history of his own country.
Geikie (ge'ki), Sir Archibald, F. R. S,f director-general of the British geological survey and an eminent authority in geological science, was born at Edinburgh, Scotland, Dec.28, 1835, and educated at the high school there and Edinburgh University. In 1855 he entered the geological s u r-vey and rose to be director - general of the geological survey oi Scotland and first Murchison professor of geology and mineralogy at the University of Edinburgh. He has been president of the British Association and of the geological society, and is director-general of the geological survey of the United Kingdom. He has written largely on his special topics, and received many foreign decorations and honors. His chief books are The Story of a Boulder, Textbook of Geology; Field Geology; Class-book of Geology; The Ancient Volcanoes oj Britain; and he has written biographies ol Edward Forbes, James D. Forbes, Sir Roderick Murchison, Sir Andrew Crombie Ramsay and other eminent scientists.
Gem'mae (in plants), peculiar reproduc^ tive bodies formed mostly by certain liverworts. Each gemma is a disk-shaped mass of cells, and on being separated from, the plant it produces a new body. See HEPATIC^.
Generative Cell (in plants), a general phrase, but technically a cell which is enveloped within pollen-grains, and which gives rise more or less directly to the male cells or sperms. It is a cell which appears in connection with the very small male gametophyte which the pollen (an asexual spore) produces.
Genet (zhe no), Edmond Charles Edouard, a French diplomatist, was born at Ver-
SIR ARCHIBALD GEIKIE
