ERSKINE, Ebenezer, clergyman, born in Ridley Park, Pennsylvania, 31 January 1821. He was graduated at Jefferson College in 1843, and at Princeton theological seminary in 1848. In 1849 he was called to the pastorate of Penn Church in Philadelphia, and was ordained by the Presbytery of Philadelphia in September of that year. He held this charge till 1851, and was then for six years pastor of the Church in Columbia, Pennsylvania He was pastor in Starling, Illinois, from 1858 till 1864, and from 1865 till 1869 edited the "Northwestern Presbyterian" in Chicago.

In 1870 he was called to the Church in Newville, Pennsylvania He was moderator of the synod of Harrisburg, and in 1878 became a director of the Princeton theological seminary. an instrument for measuring fluids by the velocity with which they pass through definite apertures; and a self registering deep sea lead, still in use by the U. S. coast survey, the principle of which was adopted in constructing the sounding apparatus used by the "Challenger" expedition. For these philosophical exhibits Ericsson was awarded the prize medal of the exhibition. Previous to 1836 Ericsson conceived the idea that was put; in practical shape when, in 1854, he presented to Emperor Napoleon III parts of a partially submerged armored vessel, with guns in a revolving shot proof cupola placed centrally on the deck. This was the first suggestion of the " Monitor," which was designed and built by him in Greenpoint, New York, in 1861, for the U. S. government, under very arbitrary conditions. When the proposition to build this vessel was accepted, the only drawing completed by the designer was a mere outline and section to illustrate the stability of the structure; but, by extraordinary energy and executive skill, calculations and working plans were made, and the "Monitor" launched, with steam machinery complete, in one hundred days from the laying of the keel.

She arrived in Hampton Roads just in time to defeat, on 9 March 1862, the Confederate ironclad "Merrimac," which, on the day preceding, had destroyed the "Cumberland" and "Congress," and was about to sink or disperse the rest of the government's wooden fleet. But for the victory of the "Monitor," the result of the war might have been changed, and European interference attempted. A fleet of monitors was then quickly built, which defeated several Confederate ironclad batteries; and Ericsson's system was taken up by European maritime powers and carried out by them on a large scale.

In 1869 he constructed for the Spanish government a fleet of thirty steam gunboats, which was intended to guard Cuba against filibustering parties. In 1881 his latest war vessel, the " Destroyer," was devised. It carries a submarine gun of sixteen inches caliber, which discharges 300 pounds of guncotton, in a 1,500pound projectile, against an ironclad's hull beneath the waterline. During many years Ericsson has devoted much time to scientific investigation, including computations of the influences that retard the earth's rotary motion. His "Sun Motor," erected at New York in 1883, develops a steady power obtained from the supply of mechanical energy stored up in the sun. This motor is intended by the designer as a contribution to applied science.

Ericsson has contributed numerous papers, on scientific, naval, and mechanical subjects, to various journals in America and Europe. In " Contributions to the Centennial Exhibition" (New York, 1876) he describes the scientific apparatus devised and employed by him in experiments which determined all important practical questions relating to radiant heat, and of numerous novel instruments by which he has demonstrated the intensity of solar energy and the temperature of the solar surface: it also contains a description of his principal engineering constructions during his residence in the United States. Many honors have been bestowed upon him. Besides receiving royal favors from Sweden, he is knight commander of royal orders in Denmark and Spain; recipient of the grand cross of naval merit from the late King Alfonso of Spain, and of a special gold medal sent by the emperor of Austria in behalf of science; has received the thanks of congress, and is a member of various scientific institutions in Europe and America. Wesleyan University gave him the degree of LL.D. in 1862. In 1867 a huge monument, quarried in one piece from the neighboring granite mines, was set up in front of his birthplace, bearing the inscription, in the Swedish language, "John Ericsson was born here, 31 July 1803." He now (1887) resides in New York City. See "Ericsson and his Inventions," "Atlantic Monthly," July 1862, and "John Ericsson," "Scribner's Monthly," April 1879o