Promotions in the Navy of the United States shall take place by Seniority or by appointment in the following proportions Viz:

Captains, Masters Commandants, and Lieutenants shall be appointed one Half by Seniority and one half by the Choice of the President who in the exercise of such Choice will be altogether influenced by considerations of the respective professional merits of the several Officers thus to be promoted.

Admirals (when the appointment of such Officers shall by Congress be deemed necessary) shall each and every of them be appointed by the Choice of the President without respect to seniority.