SIBLEY, Mark Hopkins, jurist, born in Great Barrington, Massachusetts, in 1796; died in Canandaigua, New York, 8 September, 1852, received a classical education, removed to Canandaigua in 1814, studied law, was admitted to the bar, and gained a high reputation as an advocate. He was a member of the New York legislature in 1834-'5, and was elected as a Whig to congress, serving from 4 September, 1837, till 3 March, 1839. At the close of his term he was elected a state senator, and in 1846 became county judge. He was a member of a charming social circle in Canandaigua, including Francis and Gideon Granger, John Greig, and William Wood.--His cousin, Hiram, financier, born in North Adams, Massachusetts, 6 February, 1807; died in Rochester, New York, 12 July, 1888, received a common-school education. He practised the shoemaker's trade without preparatory training, and, emigrating to western New York at the age of sixteen, worked as a journeyman machinist in a manufactory of carding-machines in Lima, and mastered three other trades before he was twenty-one years old. He carried on the wool-carding business at Sparta and Mount Morris, next established a foundry and machine-shop at Mendon, and in 1843 removed to Rochester, on being elected sheriff of Monroe county. He was instrumental in obtaining from congress an appropriation in aid of Samuel F. B. Morse's experiments, and interested himself in telegraphy from the beginning. When the invention came into practical use, the business being divided between many companies, Mr. Sibley, who, with other citizens of Rochester, was interested in two of the largest--viz., the Atlantic, Lake, and Mississippi Valley and the New York, Albany, and Buffalo--conceived the plan of uniting the scattered plants and conflicting patents in the hands of a single corporation. Lines that had proved unprofitable were purchased at nominal prices, and the telegraphs that extended over parts of thirteen states were consolidated under the name of the Western Union telegraph company, of which Sibley was president for seventeen years, during which period the value of the property grew from $220, -000 to $48,000,000. He was unable to interest his associates in a line to the Pacific coast, and constructed it alone in 1861, transferring it to the company after its completion. With the other managers, he distrusted the practicability of submarine telegraphy, and entered into the project of telegraphic communication with Europe by way of Bering strait and Siberia. He visited St. Petersburg in 1864, and obtained a promise of co-operation from the Russian government. The Western Union company expended $3,000,000 in building 1,500 miles of the projected line, but abandoned the enterprise as soon as the first message was sent over the Atlantic cable. Mr. Sibley was the principal promoter of the Southern Michigan and Northern Indiana railroad. He purchased large tracts of land in Michigan, and was interested in the lumber and salt manufacturing business at Saginaw. After the civil war he engaged largely in railroad building and various industrial enterprises in the southern states, and did much to revive business activity. He has become the largest owner of improved lands in the United States, and has in recent years engaged in farming operations on a great scale. The Burr Oaks farm, of nearly 40,000 acres, in Illinois, the Howland island farm, comprising 3,500 acres, in Cayuga, New York, and many others, are mainly devoted to seed-culture. Mr. Sibley gave 8100,000 for a building to hold a public library and the collections of Rochester university, and a like sum for the establishment of the Sibley college of mechanical engineering and the mechanic arts connected with Cornell university.