WALKER, John Grimes, naval officer, born in Hillsborough, New Hampshire, 20 March, 1835. He was graduated at the United States naval academy in 1856, promoted to master, 22 January, 1858, and became lieutenant, 23 January, 1858. During the civil war he served on the Atlantic coast blockade in the steamer "Connecticut" in 1861, and was transferred to the steamer " Winona" of the Western Gulf blockading squadron in 1862. In this vessel he participated in the engagements that ended in the capture of New Orleans, with the subsequent operations against Vicksburg in 1862. He was promoted to lieutenant-commander, 16 July, 1862, and had command of the river iron-clad "Baron de Kalb" of the Mississippi squadron in 1862-'3, in which he participated in the attacks on Vicksburg and operations in Yazoo river in the winter of 1862-'3, co-operating with General William T. Sherman and the army. He participated in both attacks on Haines's Bluff, in the Yazoo river expedition against the Confederate gun-boats, in the capture of Fort Hindman and gazoo City, and in the attack on Fort Pemberton. For these services he was highly commended by Admiral Porter in his report, and also in his "Naval History of the Civil War." After he had forced a passage through Yazoo pass, he took command of the naval battery with cannon from the gun-boats in the bombardment of Vicksburg from the rear, which contributed greatly to the final surrender. After the fall of that place he had command of the naval expedition against Yazoo river in co-operation with 5,000 troops in transports. Walker led in the "De Kalb," and while engaging the batteries his vessel ran foul of a torpedo, which exploded and caused the vessel to sink almost instantly, a second torpedo exploding under her stern as she went down. He commanded the steamer " Saco" on the North Atlantic blockade in 1864, and the " Shawmut" in 1865, in which he participated in the capture of forts near Wilmington. He was promoted and advanced over others for his services during the war to the grade of commander on 25 July, 1866, served at the naval academy in 1866-'9, and commanded the frigate " Sabine" on a special cruise in 1869-'70. He was promoted to captain, 25 June, 1877, appointed chief of the bureau of navigation and office of detail, 22 October, 1881, for four years, and reappointed in 1885 for a second term. He is the senior captain on the list, and is entitled to be promoted to commodore upon the first occurrence of a vacancy.