habitually employed in
supervising the construction of forts or field works of a nature
more permanent than the lines need by the troops in motion, and in
repairing roads and making bridges. I had several regiments of
this kind that were most useful, but as a rule we used the
infantry, or employed parties of freedmen, who worked on the
trenches at night while the soldiers slept, and these in turn
rested by day. Habitually the repair of the railroad and its
bridges was committed to hired laborers, like the English navies,
under the supervision of Colonel W. W. Wright, a railroad-engineer,
who was in the military service at the time, and his successful
labors were frequently referred to in the official reports of the
campaign.

For the passage of rivers, each army corps had a pontoon-train with
a detachment of engineers, and, on reaching a river, the leading
infantry division was charged with the labor of putting it down.
Generally the single pontoon-train could provide for nine hundred
feet of bridge, which sufficed; but when the rivers were very wide
two such trains would be brought together, or the single train was
supplemented by a trestle-bridge, or bridges made on crib-work, out
of timber found near the place. The pontoons in general use were
skeleton frames, made with a hinge, so as to fold back and
constitute a wagon-body. In this same wagon were carried the
cotton canvas cover, the anchor and chains, and a due proportion of
the balks, cheeses, and lashings. All the troops became very
familiar with their mechanism and use, and we were rarely delayed
by reason of a river, however broad. I saw, recently, in
Aldershot, England, a very complete pontoon-train; the boats were
sheathed with wood and felt, made very light; but I think these
were more liable to chafing and damage in rough handling than were
our less expensive and rougher boats. On the whole, I would prefer
the skeleton frame and canvas cover to any style of pontoon that I
have ever seen.

In relation to guards, pickets, and vedettes, I doubt if any
discoveries or improvements were made during our war, or in any of
the modern wars in Europe. These precautions vary with the nature
of the country and the situation of each army. When advancing or
retreating in line of battle, the usual skirmish-line constitutes
the picket-line, and may have "reserves," but usually the main line
of battle constitutes the reserve; and in this connection I will
stat