124 NATIONAL ACADEMY OF SCIENCES 
family at Wilmington, Delaware. With restored sight, 
Lieutenant Dahlgren, in 1843, returned to active duty in the 
Navy and made a cruise of two years’ duration in the Mediter- 
ranean in the ship Cumberland. 
In 1847, being ordered to Washington on ordnance duty, 
Lieutenant Dahlgren began the studies and labors which in 
16 years placed him at the head of the Ordnance Department 
of the Navy. In 1850 he announced the principles which he had 
evolved and after many discouragements and difficulties in 
protecting his inventions, and securing recognition for his 
ordnance system, on August 13, 1856, he was given command 
of the sloop-of-war Plymouth, with which to introduce his 
new weapons of naval warfare and especially his 11-inch 
gun. After a year’s cruise, the ship returned, all objections to 
the heavy guns having been overcome, and their inventor after 
his 11 years of labor, having obtained a complete victory for 
his ordnance principles. At the outbreak of the Civil War, 
Commander Dahlgren was placed in charge of the Washington 
Navy Yard and made Chief of the Ordnance Bureau. 
In July, 1862, he took command of the South Atlantic 
Squadron and the following year he was placed in charge of the 
fleet stationed before Charleston, S. C., succeeding Admiral 
Foote. For gallant conduct he received the thanks of Congress 
and was made a rear-admiral. At the close of the war, 
Admiral Dahlgren returned to Washington and subsequently 
was placed in charge of the South Pacific Squadron. Returning 
from the cruise, he took up his duties as Chief of the Bureau of 
Ordnance at Washington, continuing in this position until his 
death, July 12, 1870. He was the author of some important 
works on gunnery, including “ Thirty-two pound Practice for 
Ranges,” ‘“‘ Naval Percussion Locks and Primers,” and “ Shells 
and Shell Guns.” During a period of 44 years he kept a journal 
which gives vivid pictures of his life and times. 
(See MaveLeIne V. DAHticREN, “ Memoir of John A. Dahlgren,” Boston, 
1882.) 
