night), and the kind of signals that are transmitted by mirrors. Here and there,
one finds stories about other kinds of visual signals. Thus, the Bible explains how
Joshua during the Battle of Ai waved a javelin as a sign for the ambush he had
mounted to be sprung. 6 All these methods were used on occasions, sometimes
with success, sometimes without. However, all suffered from obvious limitations
in regard to range as well as the kind of information they could transmit.
Finally, it is necessary to say something about relay systems. Such systems,
consisting of mounted messengers stationed in fixed positions and taking over
from each other, were no mystery to the Hellenistic kingdoms, the Roman
Empire, and, much later, the Mongols. 7 They are capable of transmitting infor-
mation almost as fast as rumour does—speeds of up to 200 miles per day are on
record. Unlike acoustic or optical systems, they place no limits on the kind of
information that may be transmitted (though therewillbe a problem in obtain-
ing further clarification, which the messenger who delivers the message will be
unable to provide) or any difficulty concerning reliability. Still such systems suffer
from two grave disadvantages. First, the stations of which they consist are fixed in
geographical space. They are, therefore, more useful in friendly territory than in
an enemy one. More on the defence than on the offence (when one would have to
construct a new chain of stations as one advances); more on the strategic level
than on the operational one. Second, they are enormously expensive to build and
maintain.
Perhaps even more interesting than the problem of gathering information
about the enemy is that of staying in touch with, and directing the operations
of, friendly ones. Today we are used to a situation where, picking up a hand-held
gadget, we can form near-instant communication with anyone we want almost
regardless of distance, relative geographical position, relative movement, and
topographical obstacles that may separate him from us. That, however, is a recent
development; after all, mobile phones are barely a quarter-century old. Even if we
push things as far back as we can, they will go no further than the invention of
radio during the early years of the twentieth century. For half a century or so
before radio, there was only the telegraph, an instrument that is dependent on
wire and, therefore, not nearly as mobile and nearly as flexible as radio is. This
explains why, originally, at any rate, the impact of the telegraph was only felt at
the highest levels; that is, when it was a question of establishing communications
between the capital and general headquarters in the field. As one Austrian officer
wrote in 1861, only rarely was it of any use to the tactician. 8 Before the telegraph,
there was literally nothing.
Probably, the best analysis of the possibilities and limitations of operational
warfare as it was waged under such conditions comes from the pen of an
outstanding Israeli scholar, Yuval Harari, who has analysed the English armies
during the Hundred Years War (1337–1453). 9 Since the king acted as his own
commander-in-chief in the field, we shall ignore the problem of maintaining
communications between France, the theatre of war in which he operated, and
London, from which reinforcements and, at times, money would have to come.
Instead, we shall focus on the conduct of operations inside France itself.
12 The Evolution of Operational Art