Early in the present war the German field spies had their secret code
of signs, so that by drawing sketches of cattle of different colours
and sizes on gates, etc., they conveyed information to each other of
the strength and direction of different bodies of hostile troops in
the neighbourhood.

As a rule, these are residential spies, who have lived for months or
years as small tradesmen, etc., in the towns and villages now included
in the theatre of war. On the arrival of the German invaders they
have chalked on their doors, "Not to be destroyed. Good people here,"
and have done it for some of their neighbours also in order to divert
suspicion. In their capacity of naturalised inhabitants they are in
position, of course, to gain valuable tactical information for the
commanders of the troops. And their different ways of communicating it
are more than ingenious.

In some cases both spies and commanders have maps ruled off in small
squares. The watchful spy signals to his commander, "Enemy's cavalry
halted behind wood in square E15," and very soon a salvo of shells
visits this spot. A woman spy was caught signalling with an electric
flash lamp. Two different men (one of them an old one-legged
stonebreaker at the roadside) were caught with field telephones hidden
on them with wire coiled round their bodies. Shepherds with lanterns
went about on the downs at night dodging the lanterns about in various
ways which did not seem altogether necessary for finding sheep.
Wireless telegraphs were set up to look like supports to iron
chimneys.

In the South African Campaign a Dutch stationmaster acted as field
spy for the Boers for a short time. It was only a very short time. His