ter losses to the enemy than to the troops which carry it out.

ENTRENCHMENTS.--Entrenchments have been employed in the defence from
the earliest times. The Roman walls in Britain, the Great Wall of
China, the earthworks in the Russian War of 1854-1855, in the American
Civil War of 1861-1864, in the Russo-Turkish War of 1878, and the
Russo-Japanese War of 1904-1905 are notable examples. But in no war
previous to that of 1914-1918 have they played so important a part.

One of the most famous series of entrenchments in previous wars were
those constructed in 1810 by Colonel R. Fletcher, of the Royal
Engineers, at _Torres Vedras_. These fortifications extended for 50
miles and contained 126 closed works, mounting 247 guns, and behind
these lines Wellington amassed stores and reinforcements until the
retreat of Massena enabled him to resume the initiative. In front of
these lines everything that could support the French armies had been
removed; behind them Wellington's forces were well provided in every
respect. On October 10, 1810, Massena was confronted by the
entrenchments, the existence of which had been kept a profound secret,
while their strength prevented them from being carried by assault.
Before the end of October a Portuguese spy wrote to Wellington: "Heaven
forgive me if I wrong the French in believing they have eaten my cat"
(Napier). During the night of November 14-15, Massena broke up his
camp and withdrew. But it was not the lines of Torres Vedras which won
back the Peninsula. Spain and Portugal were saved by the bold march
northwards {83} to Vittoria. "In six weeks Wellington marched, with
100,000 men, 600 miles, passed six great rivers, gained one decisive
battle, invested two fortresses, and drove 120,000 veteran French
troops from Spain" (Napier).

DEFENSIVE SYSTEMS.--"Whether it is the intention of the commander to
resume the offensive at an early date or whether it is likely that the
defensive system will be occupied for a considerable period, the
principles on which the construction of all defences should be
undertaken are the same. All defensive systems should be planned from
the outset in such a way that they can easily be adapted to the
requirements of a prolonged defence. The ground must be thoroughly
reconnoitred and should at the first be divided into a series of
tactical posts and defended localities. These posts should be
self-supporting, but should be so sited that the garrisons