subject the enemy to direct observation, as well as bringing back prisoners for
interrogation. Barring actual treachery, the information these instruments might
provide would probably be more focused and more reliable than that derived
from ‘passive’ sources. 2 On the other hand, spies and patrols differed from
travellers and deserters in that they would have to cover the distance between
their employer and the enemy twice; once on their way out, once on their return.
In today’s networked world, all but the most unimportant information moves
at the speed of light. Delays, of course, are anything but unusual. However, they
are normally the result of inefficient procedures or congestion. Hence, they are
much more likely to ensue at the points of departure and arrival than on the way;
however long or short it may be, that way itself is literally covered in a flash. This
was not true in the pre-industrial world, when the speed at which news was
transmitted could vary tremendously in accordance with the weather, the topog-
raphy, the state of the roads, and so on. Owing to the all-but-seamless way in
which it was passed from mouth to ear, the kind of news that moved fastest of all
was rumour. Speeds of up to 250 miles per twenty-four hours are on record.
However, of all forms of information, rumour was the most problematic. Its
origins were unknown and its reliability uncertain; in Caesar’s words, very often
famafar outstripped the facts. 3 Furthermore, it only brought the kind of news
that happened to be floating around, as it were, not that which the commander
needed.
Other kinds of information moved much more slowly. To stick to the above
categories, travellers and deserters probably only made their way more or less at
the same speed as armies did, rarely exceeding twenty-five miles per day. This
meant that any enemy information they could provide a commander with would
only arrive a fairly short time before that enemy himself came into view. Of
course, small groups of military men on a special mission could move much
faster, especially if they were mounted. However, as already noted, they would
have to make their way to and fro, moving first forward and then back to the rear
so as to submit their report. As a result, the effective range at which they could
operate was limited indeed. Modern historians put it at two to seven miles,
though, here and there, longer ones are recorded. 4 Reading Caesar’sBellum
Africanumin particular, one gets the distinct impression that, very often, precise
information concerning the enemy’s whereabouts only reached him at the very
last moment. Even as the vanguard riding ahead of his army reported his
presence, the commander himself could see a cloud of dust rising on the hori-
zon. 5 In this sense, when Napoleon, asked how one fights a battle, answered that
‘on s’engage, puis on voit’ (first you engage, then you see), he came close to
summing up all previous military practices.
It is true that, from the earliest days on, some methods existed that could
transmit information faster than men travelling either on foot or on horseback
could. Some were acoustic—one thinks of tam-tams, or of the messages that men
stationed in posts established by the Persian emperors used to shout to each other
across the desert, or of the cannon shots that Napoleon used at the time of the
Battle of Marengo. Others were visual: smoke signals (by day), fire signals (by
Napoleon and the Dawn of Operational Warfare 11