Letter from the Secretary of the Navy, transmitting a report of the Navy Commissioners. First, in relation to the cost of the rations of seamen, &c. 2d. On the subject of commuting the rations to officers, into money. 3d. The number of officers, of each grade, necessary for the service of the year 1821. 4th. Statement of the number of pursers at this time on the rolls, and the necessity of continuing the whole in service. 5th. On the subject of dispensing with the services of superintendents, storekeepers &c. 6th. Relating to a new organization of the marine corps; and 7th. An estimated average cost per annum of various classes of vessels of war.