The thoughts that come often unsought, and, as it were, drop into the mind, are commonly the most valuable of any we have, and therefore should be secured, because they seldom return again.--=Locke.= (1632-1704.) Little Glimpses of the 19th Century. The Great Events in the History of the Last One Hundred Years, Assembled so as to Present a Nutshell Record. [_Continued from page 433._] SIXTH DECADE. 1851 Revolutionary activities continue throughout the world. President Fillmore warns American and foreign adventurers against developing plots or enterprises in this country in connection with Cuba and Mexico. Notwithstanding this, Lopez projects his second expedition against Cuba, and meets with overwhelming defeat; his trial, conviction, and execution follow. Slavery agitation becomes more and more marked; the question is not yet the existence of slavery within the States, but its admission into the Territories. The Federal enforcement of the unpopular Fugitive Slave Law produces riots in the North. Work begun upon the extensive wings of the National Capitol, the laying of the foundation stone being the occasion of one of the last great patriotic orations of Daniel Webster, Secretary of State. Webster's tilt of the preceding year with Austrian diplomats in the matter of our alleged "interference" in the struggle of Hungary for freedom had further aroused American patriotism. It had also increased sympathy for the brave people from whom success had been plucked by the intervention of Russian arms in behalf of Austria. By authority of Congress, Louis Kossuth, Hungarian patriot chief, is given an asylum on an American war vessel. He visits England and later the United States, and is received with great distinction and respect by the President and all officers of the government, acting unofficially. Founding of the Congressional Library at Washington, and of the University of Wisconsin at Madison. United States begins soundings for an Atlantic cable. The New York _Times_ and New York _Ledger_ appear. Death of J.F. Cooper, American novelist, and J.J. Audubon, American naturalist. In England, the year opens with great excitement due to the discovery of gold in Australia. The first great World's Fair is opened in London, in Hyde Park, and is a great success; exhibition building subsequently removed to Sydenham, and known as the "Crystal Palace." American yacht America wins international prize cup at the Cowes Regatta in a match around the Isle of Wight. The English colonists wage fierce warfare with Kafir and Hottentot natives in South Africa. France and England are connected by telegraphic cable. Invention of the opthalmoscope by Helmholtz. Death of Oersted, discoverer of relation between electricity and magnetism.