NEBULA 



4108 



NECKER 



(see JEWS; JERUSALEM). Nebuchadnezzar also 

 .carried on a siege of the Syrian city of Tyro, 

 but was forced to abandon it after thirteen 

 years. An inglorious invasion of Egypt was an- 

 other of his military exploits, but he shines in 

 history as a builder rather than as a warrior. 

 The Great Palace in the royal section of Baby- 

 lon, the famous Hanging Gardens (which see), 

 the walls encircling the city, magnificent forti- 

 fications and a great temple bore witness to his 

 devotion to the art of building (see BABYLON). 

 In Daniel IV is an account of a strange form 

 of madness that came upon him in the height 

 of his glory, whereby he was "driven from men, 

 and did eat grass as oxen." Nebuchadnezzar 

 died at the age of eighty-four, and with him 

 .1 away the splendor of the New Babylo- 

 nian Empire (see BABYLONIA, subhead History). 



NEB'ULA, a luminous, cloudy spot in the 

 heavens. Many apparent nebulae were resolved 

 into star clusters after the invention of the tele- 

 scope, but that true nebulae are cloudy masses 

 of luminous gas, and not clusters of stars, was 

 finally established by Sir William Huggins 

 (1864). About ten thousand nebulae are known, 

 but only the two brightest, those in the con- 

 stellations of Andromeda and Orion, are visible 

 to the naked eye. Nebulae vary in form, the 

 one in Andromeda being oval, that in Orion 

 very irregular, and others being ring-shaped or 

 spiral. The smaller nebulae usually are bright- 

 est in the center and approach the oval in 

 shape. Several double nebulae have been iden- 

 tified and others have been noted that vary in 

 brightness. With the perfection of the astro- 

 nomical camera many interesting photographs 

 of these luminous patches have been obtained. 



NEBULAR HYPOTHESIS, ncb'ulahr hi 

 poth ' e sis, a theory advanced by the French 

 astronomer Laplace to account for the forma- 

 tion of the universe. According to him the sun 

 and all the planets were formed of a nebula or 

 cloud of intensely-heated gas, which under the 

 action of gravitation assumed a globular form. 

 The mass gradually condensed and decreased 

 in size, while the velocity of motion increased. 

 Its whirling motion tended to flatten the globu- 

 lar mass at the poles; the continuing contrac- 

 tion then caused rings of nebulous matter to 

 become detached and be thrown off into space, 

 as in the case of the rings of Saturn or the 

 earth's moon. The matter detached eventually 

 collected into a globe, which continued to re- 

 volve around the central nebula from which it 

 was cast off, as the moon revolves around the 

 earth. 



This theory was first suggested by Sweden- 

 borg, and then by Kant, and later was elabo- 

 rated by Laplace, with whose name it is now 

 identified. He did not investigate the forma- 

 tion of the original nebula, but confined himself 

 to theories describing the evolution of the uni- 

 verse from the nebulous mass. The whole hy- 

 pothesis is based on the discovery of the rings 

 of Saturn, which are regarded as planets in the 

 process of formation. 



Planetesimal Hypothesis. The nebular hy- 

 pothesis is no longer generally accepted by scien- 

 tists. Among the more recent theories that 

 have claimed attention is the planetesimal hy- 

 pothesis of Chamberlin and Moulton (Univer- 

 sity of Chicago). They conceive the solar sys- 

 tem to have been formed from a spiral nebula 

 composed of gas, carrying innumerable solid 

 bodies called planetesimals. These bodies, mov- 

 ing around the center in varying orbits, tended 

 to gather together into planets and satellites. 

 See EARTH ; GEOLOGY, subtitle The Story of the 

 Earth. 



NECHO, ne'ko, an Egyptian king who 

 reached the throne about 610 B. c. and died in 

 594. During his reign the Jews came into con- 

 flict with the Egyptians; in the Biblical record 

 this king is referred to as Pharaoh-Nechoh. It 

 was he who killed King Josiah of Judah, who 

 placed Jehoiakim on the throne, and who ex- 

 acted a heavy tribute of Judah. Nebuchadnez- 

 zar encountered him later, and with his supe- 

 rior army overthrew the Egyptians and forced 

 them to give up the conquered territory. In 

 his home government Necho was more fortu- 

 nate. He had a canal built from the Nile to 

 the Red Sea, and he sent out a fleet to explore 

 the coast of Africa. 



NECK'ER, JACQUES (1732-1804), a French 

 statesman and minister of finance during one 

 of the most troubled periods in the history of 

 his country. He was of Swiss family, born at 

 Geneva, but in 1747 went to Paris, where he 

 later engaged in the banking business and 

 gained a large fortune. By reason of several 

 publications on financial subjects he was in 1777 

 made director-general of finances, and in this 

 office the general faith in his business ability 

 enabled him to borrow large sums which for a 

 time bettered the affairs of the country and 

 relieved him of the necessity of imposing in- 

 creased taxes. He held a distinguished social 

 position in the life of the capital, but his pub- 

 lication of a statement as to the financial con- 

 dition of France displeased the king, and in 

 1761 brought about his dismissal. 





