to be besieged, the war in
that country afforded very little practice in that branch of engineering
which is connected with the attack and defence of permanent works,
particularly sapping and mining. The only operation resembling a siege
was the investment and bombardment of Vera Cruz, and it is worthy of
remark that if General Scott had stormed that place, weak as it was, he
must have lost a large number of his men, while from his trenches and
batteries he reduced it with scarcely the sacrifice of a single life.

Nor did either party in this war make much use of field works in the
attack and defence of positions. Nevertheless, no one can read the
history of the war without appreciating the important influence which
Fort Brown had upon General Taylor's defence of the left bank of the Rio
Grande. Again if we compare our loss in other Mexican battles with that
which the Americans sustained in their attacks upon Monterey,
Churubusco, Molino del Key, and Chapultepec,--places partially secured
by field works--we shall be still more convinced of the value of
temporary fortifications for the defence of military positions, although
it was manifest that the Mexicans neither knew how to construct nor how
to defend them.

Nor was there much practice in this war in the use of military bridges,
for, with the exception of the Rio Grande, our armies had no important
rivers to cross. We must not, however, omit to note the important fact
that General Taylor was unable to take advantage of the victories of
Palo Alto and Resacade La Palma to pursue and destroy the army of
Arista, _because_ he had no pontoon equipage to enable him to follow
them across the Rio Grande. It should also be remarked that even a very
small bridge equipage would have been of very great use in crossing
other streams and ravines during the operations of this war. One of our
cavalry officers writes:--

"On our march from Matamaras to Victoria and Tampico, in 1846
and 1847, we had infinite difficulty in bridging boggy streams (there
being no suitable timber), and in crossing ravines with vertical banks;
a few ways of the Birago trestles would have saved us many days and
a vast amount of labor. In the operations in the valley of Mexico, our
movements, checked as they so often were by impassable wet ditches
and sometimes by dry ravines, would have been rendered so much more
free and rapid by the use of the Birago trestles, that our successes