POPULAR SCIENCE MONTHLY.
The centenary of the birth of John Ericsson was celebrated on August 1 by the unveiling of a statue in the Battery, New York City. A bronze statue by Mr. Jonathan S. Hartley had for ten years stood near the Custom House, but the sculptor wished to improve it, and at his own expense made a new statue, in which the same metal was used. By the courtesy of Mr. Hartley, we reproduce a photograph of the model as it stood in his studio. The ceremonies connected with the unveiling of the statue were elaborate, the army and navy being represented, and the Swedish-American Societies taking a prominent part. Mayor Low accepted the statue for the city and Colonel W. C. Church, author of the life of Ericsson, made an address. Both speakers naturally referred to the building of the Monitor and its destruction of the confederate ironclad Merrimac on March 9, 1862. It will be remembered that on the preceding day the Merrimac had destroyed the Cumberland and the Congress, and was about to disperse the rest of the government's wooden fleet, when the Monitor, which had been built by Ericsson in New York in one hundred days, altered the course of events and perhaps the whole result of the civil war, for if the federal government had had no fleet, European intervention would have been likely. Shortly after Ericsson came to the United States in 1839, he built the Princeton for the United States Navy, the first vessel having the propelling machinery below the water line, and this vessel set the model for all subsequent naval construction. Ericsson is consequently remembered largely in connection with the development of ships of war. to which he made the most important contributions. His other great scientific inventions, however, should not be forgotten, especially the screw propeller, which while originally designed for warships has become one of the greatest factors in steam navigation. Europe was long sceptical as to the possibility of the propeller, it being claimed that a vessel would not steer when power was applied at the stern, even after many vessels were being successfully navigated in the United States.
Ericsson began his inventions when a boy in Sweden, and at the age of twenty-two constructed a condensing flame engine of ten horse power. In 1828, when twenty-five years of age, he made the first application to navigation of the principle of condensing steam and returning water to the boiler. In 1829, when twenty-six years old, he built the steam carriage, Novelty, which competed with George Stevenson's for the Liverpool and Manchester railway prize. It surpassed all competitors, including Stevenson's Rocket, in lightness and speed, attaining the remarkable speed of thirty miles an hour. At this period and a little later he made numerous important inventions, including the tubular steam boiler with artificial draught and the caloric heat engine. He also made some important instruments for scientific work, including the self-registering deep-sea lead, a pyrometer and a hydrostatic gauge. Ericsson must be regarded as one of those who made the nineteenth century before all else an era of the applications of science.