Under these conditions there was plentiful work for despatch riders. I
am going to try and describe it for you.

When D.H.Q. are stationary, the work of despatch riders is of two kinds.
First of all you have to find the positions of the units to which you
are sent. Often the Signal Office gives you the most exiguous
information. "The 105th Brigade is somewhere near Ciry," or "The Div.
Train is at a farm just off the Paris-Bordeaux" road. Starting out with
these explicit instructions, it is very necessary to remember that they
may be wrong and are probably misleading. That is not the fault of the
Signal Office. A Unit changes ground, say from a farm on the road to a
farm off the road. These two farms are so near each other that there is
no need to inform the Div. just at present of this change of residence.
The experienced despatch rider knows that, if he is told the 105th
Brigade is at 1904 Farm, the Brigade is probably at 1894 Farm, half a
mile away.

Again, a despatch rider is often sent out after a unit has moved and
before the message announcing the move has "come through" to the
Division.

When the Division is advancing or retiring this exploration-work is the
only work. To find a given brigade, take the place at which it was last
reported at the Signal Office and assume it was never there. Prefer the
information you get from your fellow despatch riders. Then find out the
road along which the brigade is said to be moving. If the brigade may be
in action, take a road that will bring you to the rear of the brigade.
If there are troops in front of the brigade, strike for the head of it.
It is always quicker to ride from van to rear of a brigade than from
rear to van.