Robert Bonner, an American journalist, born near Londonderry, Ireland, April 28, 1824. In 1839 he came to Hartford, Conn., where his uncle was a prosperous farmer, and entered the printing office of the Hartford "Courant" as an apprentice. Here he became a thorough printer, and laid the foundation of his subsequent fortune by extra work and rigid economy. He removed to New York in 1844, was employed upon the "Evening Mirror," and acted as correspondent of the Hartford " Courant," and of newspapers in Boston, Albany, and Washington. In 1851 he founded the "New York Ledger," by purchasing the business and establishment of the " Merchant's Ledger," a weekly commercial newspaper, which he transformed into a journal of current literature and popular fiction. His enterprise in the conduct of this paper, and especially his practice of advertising to an unprecedented extent, has given it an immense circulation, at times reaching 400,000 copies. Mr. Bonner is well known as the owner of the finest stable of. trotting horses in the United States, which he never allows to take part in public races.