I may briefly state that the general objects of the expedition are: _First_, The reduction of New Orleans and all its approaches: then Mobile and its defenses: then Pensacola, Galveston, etc. It is probable that by the time New Orleans has been reduced it will be in the power of the government to reinforce the land forces sufficiently to accomplish all these objects; in the meantime you will please give all the assistance in your power to the army and navy commanders in your vicinity, never losing sight of the fact, that the great object to be achieved is the capture and firm retention of New Orleans. I am, etc., GEO. B. McCLELLAN, _Maj.-Gen. Com’g U. S. A._ General McClellan goes more into detail than does the President. He is considering the situation on more technical lines. Yet he does not go beyond the limits of strategy in outlining the general plan. He still conforms to the principles of letters of instruction. If we were to follow General Butler in his journey to the Gulf, we should perceive in his orders the disappearance of the strategic and the appearance of the tactical idea. Later we should discover one of his brigade commanders actually issuing a field order. Notice in the last example how, on account of its length, General McClellan has made a neat summary of the whole. Notice that in all of these letters the writers have adhered to the principles of rhetoric; and that they have given to the recipient a unified and coherent production. Why? Because the will of the commander is transmitted more quickly in that way. We have now completed the consideration of the expression which directly affects troops in the field. We have written the _field message_ which brings information to commanders and which helps them to make an estimate of a situation. We have framed the _field order_ which grows out of that estimate and which transforms the decision into action. We have viewed the _operation order_ which is no more than a field order made to fit trench warfare. We have seen _orders_ which are issued in connection with combat so as to govern the movement of trains. We have read letters of _instruction_ which are written by higher commanders in order to regulate in a general way extensive movements. All of these communications bear specifically upon the effort of troops toward success in battle—the ultimate object of all military training. In leaving this most important part of our professional work, we might take with us this one idea. We can best express ourselves in any of the communications we have studied by having all the thoughts of one kind together and the different kinds in an orderly arrangement. Whenever it is possible we should keep the paragraph sequence, (a) Enemy. (b) Own troops. (c) Plan. CHAPTER XI