ARMY ROAD AND BRIDGE BUILDERS.
“A line of black, which bends and floats
On the rising tide, like a bridge of boats.”
LONGFELLOW.
[Illustration]
If there is one class of men in this country who more than all others
should appreciate spacious and well graded highways, or ready means of
transit from one section into another, that class is the veterans of the
Union Army; for those among them who “hoofed it” from two to four years
in Rebeldom travelled more miles across country in that period than they
did on regularly constituted thoroughfares. Now through the woods, now
over the open, then crossing a swamp, or wading a river of varying depth,
here tearing away a fence obstructing the march, there filling a ditch
with rails to smooth the passage of the artillery,—in fact, “short cuts”
were so common and popular that the men endured the obstacles they often
presented with the utmost good-nature, knowing that every rood of travel
thus saved meant fewer foot-blisters and an earlier arrival in camp.
But there was a portion of the army which could not often indulge in
short cuts, which must “find a way or make it,” or have it made for them
by others; and as some time and much skill and labor were necessary in
laying out and completing such a way in an efficient manner, a body of
men was enlisted for the exclusive purpose of doing this kind of work.
Such a body was the _Engineer Corps_, often called the _Sappers and
Miners_ of the army; but so little sapping and mining was done, and that
little mainly by the fighting forces, I shall speak of this body of men
as _Engineers_—the name which, I believe, they prefer.
In the Army of the Potomac this corps was composed of the Fifteenth and
Fiftieth New York regiments of volunteers and a battalion of regulars
comprising three companies. They started out with McClellan in the
Peninsular Campaign, and from that time till the close of the war were
identified with the movements of this army. These engineers went armed as
infantry for purposes of self-defence only, for fighting was not their
legitimate business, nor was it expected of them. There were emergencies
in the history of the army when they were drawn up in line of battle.
Such was the case with a part of them at least at Antietam, Gettysburg,
and the Wilderness, but, so far as I can learn, they were never actively
engaged.
[Illustration: CORDUROYING.]
The engineers’ special duties were to make roads passable for the army
by corduroying sloughs, building trestle bridges across small streams,
laying pontoon bridges over rivers, and taking up the same, laying out
and building fortifications, and slashing. Corduroying called at times
for a large amount of labor, for Virginia mud was such a foe to rapid
transit that miles upon miles of this sort of road had to be laid to
keep ready communication between different portions of the army. Where
the ground was miry, two stringers were laid longitudinally of the road,
and on these the corduroy of logs, averaging, perhaps, four inches in
diameter, was laid, and a cover of brush was sometimes spread upon it to
prevent mules from thrusting their legs through. Where the surface was
simply muddy, no stringers were used. It should be said here that by far
the greater portion of this variety of work fell to fatigue details from
the infantry, as did much more of the labor which came within the scope
of the engineers’ duties; for the latter could not have accomplished
one-fifth of the tasks devolved upon them in time. In fact, if I
except the laying and taking-up of pontoon bridges, and the laying-out
and superintending of the building of forts, there were none of the
engineers’ duties which were not performed by the fighting force to a
large extent. I state this not in detraction of the engineers, who always
did well, but in justice to the infantry, who so often supplemented the
many and trying duties of their own department with the accomplishments
of the engineer corps. The quartermaster of the army had a large number
of wagons loaded with intrenching tools with which to supply the troops
when their services were required as engineers.
[Illustration: A TRESTLE BRIDGE, NO. 1.]
The building of trestle bridges called for much labor from the engineers
with the Army of the Potomac, for Virginia is gridironed with small
streams. These, bear in mind, the troops could ford easily, but the
heavily loaded trains must have bridges to cross on, or each ford would
soon have been choked with mired teams. Sometimes the bridges built by
the natives were still standing, but they had originally been put up
for local travel only, _not_ to endure the tramp and rack of moving
armies and their thousands of tons of _impedimenta_; wherefore the
engineers would take them in hand and strengthen them to the point of
present efficiency. So well was much of this work done that it endures
in places to-day as a monument to their thoroughness and fidelity, and a
convenience to the natives of those sections.
[Illustration: A TRESTLE BRIDGE, NO. 2.]
When a line of works was laid out through woods, much _slashing_, or
felling of trees, was necessary in its front. This was especially
necessary in front of forts and batteries. Much of this labor was done by
the engineers. The trees were felled with their tops toward the enemy,
leaving stumps about three feet high. The territory covered by these
fallen trees was called _the Slashes_, hence _Slashing_. No large body of
the enemy could safely attempt a passage through such an obstacle. It was
a strong defence for a weak line of works.
The _Gabions_, being hollow cylinders of wicker-work without bottom,
filled with earth, and placed on the earthworks; the _Fascines_, being
bundles of small sticks bound at both ends and intermediate points, to
aid in raising batteries, filling ditches, etc.; _Chevaux-de-frise_,
a piece of timber traversed with wooden spikes, used especially as a
defence against cavalry; the _Abatis_, a row of the large branches of
trees, sharpened and laid close together, points outward, with the
butts pinned to the ground; the _Fraise_, a defence of pointed sticks,
fastened into the ground at such an incline as to bring the points
breast-high;—all these were fashioned by the engineer corps, in vast
numbers, when the army was besieging Petersburg in 1864.
[Illustration: A LARGE GABION.]
[Illustration: FASCINES.]
[Illustration: CHEVAUX-DE-FRISE.]
But the crowning work of this corps, as it always seemed to me, the
department of their labor for which, I believe, they will be the longest
remembered, was that of ponton-bridge laying. The word _ponton_, or
pontoon, is borrowed from both the Spanish and French languages, which,
in turn, derive it from the parent Latin, _pons_, meaning a bridge, but
it has now come to mean a _boat_, and the men who build such bridges are
called by the French _pontoniers_. In fact, the system of ponton bridges
in use during the Rebellion was copied, I believe, almost exactly from
the French model.
The first ponton bridge which I recall in history was built by Xerxes,
nearly twenty-four hundred years ago, across the Hellespont. It was over
four thousand feet long. A violent storm broke it up, whereupon the
Persian “got square” by throwing two pairs of shackles into the sea and
ordering his men to give it three hundred strokes of a whip, while he
addressed it in imperious language. Then he ordered all those persons
who had been charged with the construction of the bridge to be beheaded.
Immediately afterwards he had two other bridges built, “one for the army
to pass over, and the other for the baggage and beasts of burden. He
appointed workmen more able and expert than the former, who went about it
in this manner. They placed three hundred and sixty vessels across, some
of them having three banks of oars and others fifty oars apiece, with
their sides turned towards the Euxine (Black) Sea; and on the side that
faced the Ægean Sea they put three hundred and fourteen. They then cast
large anchors into the water on both sides, in order to fix and secure
all these vessels against the violence of the winds and the current of
the water. On the east side they left three passages or vacant spaces,
between the vessels, that there might be room for small boats to go and
come easily, when there was occasion, to and from the Euxine Sea. After
this, upon the land on both sides, they drove large piles into the earth,
with huge rings fastened to them, to which were tied six vast cables,
which went over each of the two bridges: two of which cables were made of
hemp, and four of a sort of reeds called βιβλος, which were made use of
in those times for the making of cordage. Those that were made of hemp
must have been of an extraordinary strength and thickness since every
cubit in length weighed a talent (42 pounds). The cables, laid over the
whole extent of the vessels lengthwise, reached from one side to the
other of the sea. When this part of the work was finished, quite over the
vessels from side to side, and over the cables just described, they laid
the trunks of trees cut for that purpose, and planks again over them,
fastened and joined together to serve as a kind of floor or solid bottom;
all which they covered over with earth, and added rails or battlements on
each side that the horses and cattle might not be frightened at seeing
the sea in their passage.”
[Illustration: ABATIS.]
Compare this bridge of Xerxes with that hereinafter described, and note
the points of similarity.
One of the earliest pontons used in the Rebellion was made of
India-rubber. It was a sort of sack, shaped not unlike a torpedo, which
had to be inflated before use. When thus inflated, two of these sacks
were placed side by side, and on this buoyant foundation the bridge was
laid. Their extreme lightness was a great advantage in transportation,
but for some reason they were not used by the engineers of the Army of
the Potomac. They were used in the western army, however, somewhat.
General F. P. Blair’s division used them in the Vicksburg campaign of
1863.
[Illustration: THE FRAISE.]
Another ponton which was adopted for bridge service may be described as
a skeleton boat-frame, over which was stretched a cotton-canvas cover.
This was a great improvement over the tin or copper-covered boat-frames,
which had been thoroughly tested and condemned. It was the variety
used by Sherman’s army almost exclusively. In starting for Savannah, he
distributed his ponton trains among his four corps, giving to each about
nine hundred feet of bridge material. These pontons were suitably hinged
to form a wagon body, in which was carried the canvas cover, anchor,
chains, and a due proportion of other bridge materials. This kind of
bridge was used by the volunteer engineers of the Army of the Potomac. I
recall two such bridges.
One spanned the Rapidan at Ely’s Ford, and was crossed by the Second
Corps the night of May 3, 1864, when it entered upon the Wilderness
campaign. The other was laid across the Po River, by the Fiftieth New
York Engineers, seven days afterwards, and over this Hancock’s Veterans
crossed—those, at least, who survived the battle of that eventful
Tuesday—before nightfall.
But all of the _long_ bridges, notably those crossing the Chickahominy,
the James, the Appomattox, which now come to my mind, were supported by
_wooden_ boats of the French pattern. These were thirty-one feet long,
two feet six inches deep, five feet four inches wide at the top, and
four feet at the bottom. They tapered so little at the bows and sterns
as to be nearly rectangular, and when afloat the gunwales were about
horizontal, having little of the curve of the skiff.
[Illustration: A CANVAS PONTOON BOAT. FROM A PHOTOGRAPH.]
The floor timbers of the bridge, known as _Balks_, were twenty-five and
one-half feet long, and four and one-half inches square on the end. Five
continuous lines of these were laid on the boats two feet ten inches
apart.
The flooring of the bridge, called _chesses_, consisted of boards having
a uniform length of fourteen feet, a width of twelve inches, and a
thickness of one and a half inches.
To secure the chesses in place, _side-rails_ of about the same dimensions
as the balks were laid upon them over the outer balks, to which the rails
were fastened by cords known as _rack-lashings_.
The distance between the centres of two boats in position is called a
_bay_. The distance between the boats is thirteen feet ten inches. The
distance between the side-rails is eleven feet, this being the width of
the roadway.
[Illustration: AN ANGLE OF FORT HELL (SEDGWICK) SHOWING GABIONS,
CHEVAUX-DE-FRISE, ABATIS AND FRAISE. FROM A PHOTOGRAPH.]
An _abutment_ had to be constructed at either end of a bridge, which was
generally done by settling a heavy timber horizontally in the ground,
level with the top of the bridge, confining it there by stakes. A proper
approach was then made to this, sometimes by grading, sometimes by
corduroying, sometimes by cutting away the bank.
The boats, with all other bridge equipage, were carried upon wagons,
which together were known as the Ponton Train. Each wagon was drawn by
six mules. A single boat with its anchor and cable formed the entire load
for one team. The balks were loaded on wagons by themselves, as were also
the chesses, and the side-rails on others. This system facilitated the
work of the pontoniers. In camp, the Ponton Train was located near army
headquarters. On the march it would naturally be in rear of the army,
unless its services were soon to be made use of. If, when the column had
halted, we saw this train and its body-guard, the engineers, passing to
the front, we at once concluded that there was “one wide river to cross,”
and we might as well settle down for a while, cook some coffee, and take
a nap.
In order to get a better idea of ponton-bridge laying, let us follow
such a train to the river and note the various steps in the operation.
If the enemy is not holding the opposite bank, the wagons are driven as
near as practicable to the brink of the water, unloaded, and driven off
out of the way. To avoid confusion and expedite the work, the corps is
divided up into the abutment, boat, balk, lashing, chess, and side-rail
parties. Each man, therefore, knows just what he has to do. The abutment
party takes the initiative, by laying the abutment, and preparing the
approaches as already described. Sometimes, when the shore was quite
marshy, trestle work or a crib of logs was necessary in completing this
duty, but, as the army rarely approached a river except over a recognized
thoroughfare, such work was the exception.
While this party has been vigorously prosecuting its special labors,
the _boat party_, six in number, have got a ponton afloat, manned it,
and ridden to a point a proper distance above the line of the proposed
bridge, dropped anchor, and, paying out cable, drop down alongside the
abutment, and go ashore. The _balk party_ are on hand with five balks,
two men to each, and having placed these so that one end projects six
inches beyond the outer gunwale of the boat, they make way for the
_lashing party_, who lash them in place at proper intervals as indicated
on the gunwales. The boat is then pushed into the stream the length of
the balks, the hither ends of which are at once made fast to the abutment.
[Illustration: A WOODEN PONTOON BOAT. FROM A PHOTOGRAPH.]
The _chess party_ now step to the front and cover the balks with flooring
to within one foot of the ponton. Meanwhile the boat-party has launched
another ponton, dropped anchor in the proper place, and brought it
alongside the first: the balk party, also ready with another bay of
balks, lay them for the lashing party to make fast; the boat being then
pushed off broadside-to as before, and the free end of the balks lashed
so as to project six inches over the _shore_ gunwale of the first boat.
By this plan it may be seen that each balk and bay of balks completely
spans two pontons. This gives the bridge a firm foundation. The chess
party continue their operations, as before, to within a foot of the
second boat. And now, when the third bay of the bridge is begun, the
_side-rail_ party appears, placing their rails on the chesses over the
outside balks, to which they firmly lash them, the chesses being so
constructed that the lashings pass between them for this purpose.
The foregoing operations are repeated bay after bay till the bridge
reaches the farther shore, when the building of another abutment and
its approaches completes the main part of the work. It then remains to
scatter the roadway of the bridge with a light covering of hay, or straw,
or sand, to protect it from wear, and, perhaps, some straightening here
and tightening there may be necessary, but the work is now done, and all
of the _personnel_ and _matériel_ may cross with perfect safety. No rapid
movements are allowed, however, and man and beast must pass over at a
walk. A guard of the engineers is posted at the abutment, ordering “Route
step!” “Route step!” as the troops strike the bridge, and sentries, at
intervals, repeat the caution further along. By keeping the cadence in
crossing, the troops would subject the bridge to a much greater strain,
and settle it deeper in the water. It was shown over and over again that
nothing so tried the bridge as a column of infantry. The current idea is
that the artillery and the trains must have given it the severest test,
which was not the case.
In taking up a bridge, the order adopted was the reverse of that followed
in laying it, beginning with the end next the enemy, and carrying the
chess and balks back to the other shore by hand. The work was sometimes
accelerated by weighing all anchors, and detaching the bridge from the
further abutment, allow it to swing bodily around to the hither shore
to be dismantled. One instance is remembered when this manœuvre was
executed with exceeding despatch. It was after the army had recrossed the
Rappahannock, following the battle of Chancellorsville. So nervous were
the engineers lest the enemy should come upon them at their labors they
did not even wait to pull up anchors, but cut every cable and cast loose,
glad enough to see their flotilla on the retreat after the army, and more
delighted still not to be attacked by the enemy during the operation,—so
says one of their number.
One writer on the war speaks of the engineers as grasping “not the musket
but the _hammer_,” a misleading remark, for not a nail is driven into the
bridge at any point.
[Illustration: A PONTOON BRIDGE AT BELLE PLAIN, VA. FROM A PHOTOGRAPH.]
When the Army of the Potomac retreated from before Richmond in 1862 it
crossed the lower Chickahominy on a bridge of boats and rafts 1980 feet
long. This was constructed by three separate working parties, employed
at the same time, one engaged at each end and one in the centre. It was
the longest bridge built in the war, of which I have any knowledge,
save one, and that the bridge built across the James, below Wilcox’s
Landing, in 1864. This latter was a remarkable achievement in ponton
engineering. It was over two thousand feet long, and the channel boats
were firmly anchored in thirteen fathoms of water. The engineers began it
during the forenoon of June 14, and completed the task at midnight. It
was built under the direction of General Benham for the passage of the
wagon-trains and a part of the troops, while the rest crossed in steamers
and ferry-boats.
But ponton bridges were not always laid without opposition or
interference from the enemy. Perhaps they made the most stubborn contest
to prevent the laying of the bridges across the Rappahannock before
Fredericksburg in December, 1862.
The pontoniers had partially laid one bridge before daylight; but when
dawn appeared the enemy’s sharpshooters, who had been posted in buildings
on the opposite bank, opened so destructive a fire upon them that they
were compelled to desist, and two subsequent attempts to continue the
work, though desperately made, were likewise brought to naught by the
deadly fire of Mississippi rifles. At last three regiments, the Seventh
Michigan, and the Nineteenth and Twentieth Massachusetts, volunteered
to cross the river, and drive the enemy out of cover, which they did
most gallantly, though not without considerable loss. They crossed the
river in ponton boats, charged up the steep bank opposite, drove out, or
captured the Rebels holding the buildings, and in a short time the first
ponton bridge was completed. Others were laid near by soon after. I
think the engineers lost more men here—I mean now in actual combat—than
in all their previous and subsequent service combined.
[Illustration: POPLAR GROVE CHURCH.]
Ponton bridges were a source of great satisfaction to the soldiers. They
were perfect marvels of stability and steadiness. No swaying motion was
visible. To one passing across with a column of troops or wagons _no_
motion was discernible. It seemed as safe and secure as mother earth, and
the army walked them with the same serene confidence as if they were. I
remember one night while my company was crossing the Appomattox on the
bridge laid at Point of Rocks that D. Webster Atkinson, a cannoneer,
who stood about six feet and a quarter in boots—dear fellow, he was
afterwards mortally wounded at Hatcher’s Run,—being well-nigh asleep from
the fatigue of the all-night march we were undergoing, walked off the
bridge. Fortunately for him, he stepped—not into four or five fathoms of
water, but—a ponton. As can readily be imagined, an unexpected step down
of two feet and a half was quite an “eye-opener” to him, but, barring a
little lameness, he suffered no harm.
The engineers, as a whole, led an enjoyable life of it in the service.
Their labors were quite fatiguing while they lasted, it is true, but they
were a privileged class when compared with the infantry. But they did
well all that was required of them, and there was no finer body of men in
the service.
The winter-quarters of the engineers were, perhaps, the most unique of
any in the army. In erecting them they gave their mechanical skill full
play. Some of their officers’ quarters were marvels of rustic design. The
houses of one regiment in the winter of ’63-4 were fashioned out of the
straight cedar, which, being undressed, gave the settlement a quaint but
attractive and comfortable appearance.
Their streets were corduroyed, and they even boasted sidewalks of
similar construction. Poplar Grove Church, erected by the Fiftieth New
York Engineers, a few miles below Petersburg, in 1864, still stands, a
monument to their skill in rustic design.
[Illustration]