All officers of the administrative departments;
All officers of artillery and engineer staffs;
The corps of geographical or topographical engineers, and
The guards.
In the second class are included all troops, of whatever arm, which belong to the active army, in infantry, cavalry, artillery, and engineers. All troops on detached service, such as recruiting, guarding posts and dépôts, escorting convoys, &c., as well as all sedentary corps, garrisons of fortified places, &c., are not regarded in this classification as composing any part of the line of the army.
Troops of the line is a term applied only to such troops as form the principal line on the battle-field, viz:—The heavy infantry and heavy cavalry. These are technically called infantry of the line, and cavalry of the line. In this sense of the term, light infantry, light cavalry or dragoons, artillery, and engineers, are not classed as troops of the line. But this distinction is now pretty much fallen into disuse, and the division of an army into Staff and Administrative departments, and four arms of service—Infantry, Cavalry, Artillery, and Engineers—is now regarded as the most convenient, from being precise and definite in its meaning.
The general staff of an army includes all general officers of the army, and such officers of lower grades as are attached to this general duty, instead of serving with troops, or on special administrative duty. The general officers are—1st, the generalissimo, or commander-in -chief; 2d, generals, or marshals, as they are called in France, or field-marshals and generals of infantry and cavalry, as they are called in England and the northern states of Europe; 3d, lieutenant-generals; 4th, generals of division, or major-generals, as they are called in England; 5th, generals of brigade, or brigadier-generals, as they are sometimes called;—colonels, majors, captains, lieutenants, ensigns, and cornets or cadets, are also either attached to the staff, or form a part of the staff corps. The titles of "adjutant-general," and of "inspector-general," are given to staff officers selected for these special services, either in the general staff or in the several corps d'armée. No special rank is attached to these offices themselves, and the grade of those who hold them is fixed by some special rule, or by their general rank in the army.
In the war of the Revolution, Washington held the rank of General, and in 1798 the rank of Lieutenant-general. In the war of 1812, the highest grade held by any of our officers was that of General of Division, or Major-general, as it was called. The highest grade in our army at the present time is called Major-general—a title that properly belongs, not to the general of an army, but to the chief of staff. Hamilton had this title when chief of Washington's staff; Berthier and Soult when chief of Napoleon's staff, the former till the close of the campaign of 1814, and the latter in the Waterloo campaign. General Jomini first greatly distinguished himself as chief of Ney's staff, and afterwards on the staff of the Emperor of Russia. Other generals have owed much of their success to the chiefs of their staff:—Pichegru to Regnier, Moreau to Dessoles, Kutusof to Toll, Barclay to Diebitsch, and Blücher to Sharnharst and Gneisenau.
The generalissimo or commander-in-chief of an army is the person designated by the law of the land to take charge of the organized military forces of the state. In this country the President, through his Secretary of War, exercises this general command. In England, Wellington acts in the capacity of commander-in-chief of all the British military forces. In France, the Minister of War, under the king, has this general direction. In other European services, some prince of the blood, or distinguished general, exercises the functions of generalissimo.
An active army in the field should be commanded by a general, or, as is done in some European countries, by a marshal. These may be regarded as of assimilated rank.