In 1825 he was appointed midshipman in the United States navy, making his first cruise in the Brandywine, on the coast of Europe and in the Mediterranean. In 1826 he made a cruise around the world in the Vincennes. In 1831 he was master of the sloop-of-war Falmouth, but was soon acting first lieutenant on the Dolphin, then transferred to the frigate Potomac, in which he returned to the United States.
At the age of 28 he published his first work, “Maury’s Navigation,” which was at once adopted as a text-book in the navy!
He was at this time selected as astronomer and offered the place of hydrographer to the exploring expedition to the South Seas, but declined.
In 1837 he was made lieutenant, and not long after met with the accident which lamed him for life.
While unable for active duty, he cultivated his mind, and by his views published in the “Southern Literary Messenger,” worked great reforms in the navy and secured a naval academy.
He first directed the observations of the flow of the Mississippi. He proposed a system which would enable the observers to give information by telegraph, as to the state of the river and its tributaries. He suggested to Congress efficacious plans for the disposition of the drowned lands on the Mississippi. He brought forward and successfully advocated a warehousing system. In 1842 he was appointed superintendent of the depot of charts and instruments at Washington. He added to his labors of astronomer the task of unraveling the winds and currents of the ocean. He instituted the system of deep sea sounding, leading directly to the establishment of telegraphic communication between the continents by cable.
The “Physical Geography of the Sea,” translated into various languages, is an enduring monument to the genius and usefulness of its author. The powers of Europe recognized the value of his services to mankind. France, Austria, Russia, Prussia, Denmark, Belgium, Portugal, Sweden, Sardinia, Holland, Bremen and the Papal States bestowed orders of knighthood and other honors.
The academies of science of Paris, Berlin, Brussels, St. Petersburg and Mexico conferred the honors of membership.
He left the Federal navy to aid his own State, when Virginia seceded, declining from a sense of duty highly honorable positions from Russia and France.
There have been few greater scientists in the world. Humboldt pronounced him “the greatest the world had ever known.”