for concealment on marches, which is often very important. But still further, it makes it far easier to obtain the proper planking in single lengths, the only way in which these boats should ever be constructed to secure the proper strength and tightness. Of the great advantage of this reduction in length of the wooden pontoons I have not the slightest doubt; but the main question is, are these wooden pontoons the best and most expedient for use with an army where much land transportation is required? I have no hesitation in expressing my belief that they are not the best, and I doubt not that, except where they may be needed for permanent bridges, or where they can have water transportation the greater part of the distance, the iron pontoon of somewhat near the form proposed by Mr. Francis, when strengthened in some parts and with some slight modification, will be altogether the best under all circumstances for field service. But of those now in use with us I give the preference altogether for field transportation to the canvas pontoon-boat, and of the present length, 22 feet, which appears to be sufficient.

On the march to Chancellorsville in April last three corps with their artillery passed most successfully over such a bridge, a couple of buckets only being ample for the bailing of all the boats. The pontoon itself, complete, weighs less than 700 pounds, being from two-fifths to less than two-sevenths of the wooden pontoon, and is such that while the bridge part proper remains the same, the total number of animals need not be more than two-thirds of those required for the ordinary trains; while there are no large, heavy, and unwieldly loads, as is the case with the wooden pontoons-about two-thirds of such trains. This secure greater rapidity and facility of movement. While the first cost of the canvas pontoon is less, and taking into account the repairs of wooden pontoons so constantly necessary, especially in hot climates and always after marches, I feel safe in saying it is cheaper and more durable in the long run. I am so convinced of this that I have no hesitation in recommending for future use the canvas pontoon trains for the general service of our armies, the wooden boats being retained, or constructed only for special cases where they are manifestly indispensable and will not require much land transportation.

On one subject further with reference to these pontoon trains it may be proper to express my opinion, which is most decided, that either at this point or at some other position, if there be one as suitable, which I do not think to be the case, however, all things considered, there should be a depot for recruits for the drill of pontoniers for all the armies. Such selected depot or station for drill is more important, as I do not hesitate to say, for this than for any other arm of the service, for, as it is obvious, the tactical drills of artillery, infantry, and cavalry, and even the practice of engineers in the construction of field-works, gabions, fascines, can be carried on almost anywhere, even in the very front of the enemy; but this is not the case with pontoon drills, which must be at the rear, in some selected position, away from the front or rivers (usually the dividing lines), near which the trained pontoniers should be with their equipage. I have had a full experience in relation to this point in my efforts for the drill of parts of my command at Belle Plain and elsewhere last season. After much of labor to the troops by the constant transfer of small portions of the command to those points for pontoon drill, the results were far from satisfactory, while within the first few weeks after my command reached this position the progress