Now You Know, October 2023, Section 1 of 2
So, Who Was John Dahlgren Anyway?
By Dr. Rob Gates

When I give a museum tour, I always start at the photograph of Admiral John A. Dahlgren. It’s not unusual to get questions like “Was he born around here?” or “When was he stationed here?” The answers to those questions are, respectively, “No” and “Never.” So, who was John Dahlgren, and why is this place named after him?
John Adolphus Bernard Dahlgren was born in Philadelphia in 1809. His parents, Bernhard and Martha Dahlgren, were well educated and on the edge – geographically and financially – of Philadelphia society, and John knew the children of the top families. His parents insisted that he be given a proper education, and he received top grades in mathematics, science, and Latin at a Quaker school.
Dahlgren’s world changed when his father died in 1824 and left the family in dire financial straits. He applied for an appointment as a midshipman in the Navy but was turned down. He worked for a time as a church secretary and decided to reapply. This time, however, he did something different and, following a pattern that he used throughout his life and career, used outside influence; in this case, that of prominent citizens of Philadelphia and family friends. Dahlgren was appointed as a midshipman in February 1826 and in April was ordered to serve on the Macedonian on a cruise to South America. That was followed by a cruise to the Mediterranean on the Ontario. So far, his career was much like that of any midshipman, but things were to take a turn. Dahlgren’s cruise was cut short by illness, and he was sent home on the Constellation. He used his three month’s leave to go to the Norfolk Navy School to study for his promotion examination. He passed and was assigned to a receiving ship in Philadelphia as a Passed Midshipman.
In June 1833, Dahlgren got sick again and took an unplanned year’s leave to recover his health. When he returned to active duty in 1834, he was assigned to the United States Geodetic Survey as an assistant to Superintendent Ferdinand Hassler. This took advantage of his skills in mathematics and science and was a turning point in his career. Hassler believed in continuing the education of his assistants, and Dahlgren received the equivalent of a graduate education in mathematics from him. He excelled in his assignments and, as his responsibilities grew, he took on additional duties as a leader of a survey team. He quickly found that his pay was half that of the civilian members of his team and campaigned for a promotion or pay increase. Both were turned down and, as before, he used influence outside of the Department of the Navy and wrote a letter to his senator, who pressured the Secretary of the Navy. He received promotion to lieutenant.
Unfortunately, the close work Dahlgren was doing damaged his eyes, and in 1837 he was sent to the naval hospital in Philadelphia for treatment. When his eyes did not improve, he requested leave to go to Paris – on full pay – for treatment. He spent six months there but, again, there was little improvement. He was offered a choice – go to sea and possibly lose his sight or on furlough at half pay. He objected to half pay on the basis that he had a service-related injury. After his proposal was rejected, he appealed to his congressman, who had the decision reversed. He was on leave until 1842.
About the Author

Dr. Robert V. Gates is vice president of the Dahlgren Heritage Foundation. He had a long and varied career at NSWC Dahlgren Division and retired after serving as the technical director of the Indian Head Division, NSWC. His various degrees attest to his commitment to lifelong learning, and he supports his community through offices and membership on various boards.