In September, Maury had had the good fortune to be appointed “Astronomer” for the expedition with $1000 additional pay, and also as assistant to the “Hydrographer”, Lieutenant James Glynn. To prepare himself for these duties he went to Philadelphia, where in a little observatory in Rittenhouse Square he soon familiarized himself with the use of astronomical instruments. The expedition, however, still delayed to set sail, and the vexatious interference with his command so affected Captain Jones’s health as to give the Secretary of the Navy an excuse for removing him from his position. Matters had by this time come to such a pass that several officers declined the command when it was offered them; namely, Captains Shubrick, Kearny, Perry, and Gregory. Finally, in April, 1838, a junior officer, Lieutenant Charles Wilkes, though there were eighty lieutenants above his grade, was selected, and he accepted the appointment. The sloops of war _Vincennes_ and _Peacock_ and two smaller vessels were chosen instead of those originally prepared, and it became necessary to reorganize the personnel of the expedition. Maury had sympathized with Captain Jones in the unjust treatment which he had received from the Secretary of the Navy, and besides he had written that Wilkes was the only officer in the navy with whom he would not coöperate provided that he was put in command of the enterprise. He therefore asked to be detached from the expedition. Maury might possibly have had the honor of commanding the exploring expedition himself, as clearly indicated by the following letter which he wrote years afterwards: “The expedition had been taken away from the Secretary of the Navy and transferred to Poinsett, Secretary of War. I was ordered to fetch the instruments to Washington and report myself to Poinsett. He received me with open arms, took me into his bosom, and asked me to give him the names of the officers _without regard to rank_ that _I_ thought best qualified for the expedition. I afterwards had reason to suppose that he expected me to name myself and intended to put me in command of it, as really I was the most important personage in it—Hydrographer and Astronomer. But I asked myself, what right have I to draw distinctions among brother officers? So I gave him a list of the officers belonging to the expedition; myself, the youngest lieutenant in the navy, at the bottom of the list. He froze up with disgust, ordered Wilkes home, and gave him the command, and so I was the gainer, for I preserved mine integrity”.