Of the voyage of the little craft from New York to Hampton Roads, and of her epoch-making battle with the Merrimac we have already told. Ericsson had asked that she be named the "Monitor," as a warning to the nations of the world that a new era in naval warfare had begun, and that she was well-named no one could doubt after that momentous ninth of March, 1862. Honors were showered upon the inventor, whose great service to the nation could not be questioned. The following ten years of his life were devoted to the construction of his famous torpedo-boat, the "Destroyer," which, he believed, would annihilate any vessel afloat--the predecessor of all the torpedo-boats, past and present, which have played so important a part in naval warfare. He lived for more than twenty years in a house in Beach street, New York, where he died, in 1889. The Monitor's attack upon the Merrimac would have been ineffective but for the remarkable guns with which the little craft was armed--two eleven-inch rifled cannon, the invention of John Adolph Dahlgren. Dahlgren had been connected with the ordnance department of the navy at Washington for many years, and his inventions had revolutionized United States gunnery. Dahlgren was born at Philadelphia, where his father was Swedish consul, a position which he held until his death in 1824. The boy, from his earliest years, had been ambitious to enter the navy, and finally, at the age of seventeen, received his midshipman's warrant. In 1847, he was assigned to ordnance duty at Washington, and began that career of extraordinary energy, which lasted for sixteen years. He saw almost at once the many defects in the cannon which were at that time being manufactured, and soon offered a design of his own, which proved a vast advance over old guns. The Dahlgren gun, as it was called, was of iron, cast solid, with a thick breech adjusted to meet varying pressure strains. The invention of the rifled cannon followed, and it was this weapon which caused even the great armored Merrimac to tremble. Admiral Dahlgren's career was a distinguished one, but no service he rendered his country was more noteworthy than this. But there are triumphs of peace, as well as of war, and one of the most notable of these was won by Cyrus Hall McCormick when he invented the automatic reaper which bears his name. In 1859, it was estimated that the reaper was worth $55,000,000 a year to the United States; William H. Seward remarked that, "owing to Mr. McCormick's invention, the line of civilization moves westward thirty miles each year"; and the London Times declared, after it had been tested at the great international exhibition of 1851, that it was "worth to the farmers of England the whole cost of that exhibition." To few men is it given to confer such benefits upon mankind, and the career of this one is well worth dwelling upon.