A collected edition of his works appeared at St Petersburg in 8 volumes, 1860-1861.
DAHLBERG (DAHLBERGH), ERIK JOHANSEN, COUNT (1625-1703), Swedish soldier and engineer, was born at Stockholm. His early studies took the direction of the science of fortification, and as an engineer officer he saw service in the latter years of the Thirty Years' War, and in Poland. As adjutant-general and engineer adviser to Charles X. (Gustavus), he had a great share in the famous crossing of the frozen Belts, and at the sieges of Copenhagen and Kronborg he directed the engineers. In spite of these distinguished services, Dahlberg remained an obscure lieutenant-colonel for many years. His patriotism, however, proved superior to the tempting offers Charles II. of England made to induce him to enter the British service, though, in that age of professional soldiering, there was nothing in the offer that a man of honour could not accept. At last his talents were recognized, and in 1676 he became director-general of fortifications. In the wars of the next twenty-five years Dahlberg again rendered distinguished service, alike in attack (as at Helsingborg in 1677, and Dünamünde in 1700) and defence (as in the two sieges of Riga in 1700): and his work in repairing the fortresses of his own country, not less important, earned for him the title of the "Vauban of Sweden." He was also the founder of the Swedish engineer corps. He retired as field-marshal in 1702, and died the following year.
Erik Dahlberg was responsible for the fine collection of drawings called _Suecia antiqua et hodierna_ (Stockholm, 1660-1716; 2nd edition, 1856; 3rd edition, 1864-1865), and assisted Pufendorf in his _Histoire de Charles X Gustave_. He wrote a memoir of his life (to be found in Svenska Bibliotek, 1757) and an account of the campaigns of Charles X. (ed. Lundblad, Stockholm, 1823).
DAHLGREN, JOHN ADOLF (1809-1870), admiral in the U.S. navy, was the son of the Swedish consul at Philadelphia, Pennsylvania, and was born in that city on the 13th of November 1809. He entered the United States navy in 1826, and saw some service in the Civil War in command of the South Atlantic blockading squadron. But he was chiefly notable as a scientific officer. His knowledge of mathematics caused him to be employed on the coast survey in 1834. In 1837 his eyesight threatened to fail, he retired in 1838-1842, and in 1847 he was transferred to the ordnance department. In this post he applied himself to the improvement of the guns of the U.S. navy. He was the inventor of the smooth bore gun which bore his name, but was from its shape familiarly known as "the soda water bottle." It was used in the Civil War, and for several years afterwards in the United States navy. Dahlgren's guns were first mounted in a vessel named the "Experiment," which cruised under his command from 1857 till 1859. They were "the first practical application of results obtained by experimental determinations of pressure at different points along the bore, by Colonel Bomford's tests--that is by boring holes in the walls of the gun, through which the pressure acts upon other bodies, such as pistol balls, pistons, &c." (Cf. article by J. M. Brooke in Hamersley's _Naval Encyclopaedia_.) When the Civil War broke out, he was on ordnance duty in the Washington navy yard, and he was one of the three officers who did not resign from confederate sympathies. His rank at the time was commander, and the command could only by held by a captain. President Lincoln insisted on retaining Commander Dahlgren, and he was qualified to keep the post by special act of Congress. He became post-captain in 1862 and rear-admiral in 1863. He commanded the Washington navy yard when he died on the 12th of July 1870.