DORNIN, Thomas Aloysius, naval officer, born in Ireland about 1800 ; died in Norfolk, Virginia, 22 April 1874. He was appointed midshipman, 2 May 1815, and lieutenant in 1825. After cruising in the Pacific, he volunteered in the sloop-of-war "Vincennes," bound round the world, and returned in her in 1830. After again cruising in the Pacific, he was appointed to the command of the store ship "Relief" on the fitting out of the South sea exploring expedition. While in command of the "Shark," in the Pacific, he was commissioned commander (1841) and given charge of the sloop "Dale," which he brought home from a cruise in 1843. In 1851 he sailed in command of the "Portsmouth," and during his cruise he was ordered to charter one of the Panama steamers and endeavor to prevent the invasion of Mexican territory by William Walker's expedition. In the execution of this design he was completely successful. After discharging his steamer he visited Mazatlan, where he found forty American citizens, who had been peaceably doing business in Guaymas, closely packed in the hold of a schooner, doubly ironed, and chained to the bottom of the vessel. Captain Dornin at once demanded of the governor their immediate release, and after considerable delay that official finally complied. Dornin then sailed for Acapulco, where he learned that a Mexican warvessel had declared a blockade and driven off U. S. mail steamers. Hepursued and overhauled the vessel, and notified her commander that such proceedings were in violation of a special treaty between the United States and Nexico. The Mexican, after making a written protest, abandoned the blockade. After being commissioned as captain (1855), and while in command of the "San Jacinto," Dornin captured two slave vessels on the coast of Africa with over 1,400 slaves on board, and landed them safely in Liberia. During the civil war he was promoted to the rank of commodore on the retired list (16 July 1862), and at its close was placed in charge of the fifth lighthouse district.