_The Credit Mobilier_ was a company organized for the purpose of building the Pacific Railroad. The undertaking proved a profitable one, and enormous dividends were paid. An investigation developed the startling fact that various high officers of the government had accepted presents of stock, the value of which necessarily depended largely upon their official action. _Railroad Panic._--In the autumn of 1873, Jay Cooke & Co., bankers of Philadelphia, having engaged too extensively in railroad schemes, failed. A financial crisis ensued, and hundreds of prominent firms all over the Union were involved in ruin. A settled stringency of the money market and a stagnation of business followed. _Centennial Anniversaries._--The year 1875, being the hundredth anniversary of the first year of the Revolutionary War, was marked by various centennial observances. April 19, the battles of Lexington and Concord were celebrated with patriotic pride. May 20, the citizens of Mecklenburg County, North Carolina, honored the memory of those who, at Charlotte, signed a Declaration of Independence only ten days after the capture of Ticonderoga. June 17 witnessed, at Bunker Hill, an unprecedented gathering from all parts of the country, Northern and Southern soldiers vying in devotion to the flag of the Union. _The Centennial Exhibition._--To commemorate the signing of the Declaration of Independence, an exhibition of the arts and industries of all nations was held at Philadelphia, during the summer of 1876. The beautiful grounds of Fairmount Park were the scene of this imposing display. The principal edifices were the Main Exhibition Building, the Memorial Hall, the Machinery Hall, the Horticultural and Agricultural Buildings, and the Woman's Pavilion. The first named covered an area of over twenty-six acres In addition to these structures, there were more than two hundred smaller buildings scattered over the extensive grounds. The exhibition opened May 10, and lasted six months. The average daily attendance was about 61,000 persons. [Illustration: THE UNITED STATES GOVERNMENT BUILDING AT THE CENTENNIAL EXHIBITION] [Footnote: See Barnes's Hundred Years of American Independence, a supplement to which is entirely devoted to the Centennial Exhibition.] _War with the Sioux_ (1877) [Footnote: The Black Hills which are in Dakota and Wyoming belonged to the Sioux Reservation But gold having been found there bands of miners began to prospect on the Indian domain, a bill was introduced into Congress to extinguish the Indian title to a portion of the Black Hill region and finally a new treaty as negotiated But the unwillingness of the Indians to leave the encroachments of the whites and the advent of surveyors and troops all combined to provoke hostilities]