"Since we have been compelled, in self-defence, to use similar methods,
it is satisfactory to be able to record, on the evidence of prisoners,
of documents captured, and of our own observation, that the enemy
has suffered heavy casualties from our gas attacks, while the means
of protection adopted by us have proved thoroughly effective."

One of the causes which leads to a lack of understanding of the chemical
weapon is the fact that the results of chemical attack are not,
like those of a huge assault, obvious to the mere visual observer.
A period of months often elapsed during the war before the immediate
effect of a gas attack was known. It was inspiring to witness
the assault of the 18th Division near Montauban on July 1st, 1916.
But few realised the part played by the preparatory gas
attacks in that and other sectors of the line, in weakening
the numerical strength and battle morale of effective reserves.
It is, therefore, of great interest to follow up a particular case
and to obtain a connected idea of the series of events associated
with some particular attack.

The early stages of the Somme battle were characterised by a
number of cloud gas attacks which served the double purpose
of a feint, and reducing the strength of available reserves.
These attacks occurred chiefly along the part of the line north
of the Somme battle zone, and they extended as far as the sea.
One of them occurred on the 30th August, 1916, at Monchy, between Arras
and Bapaume. About one thousand cylinders were discharged during
the night. The usual careful organisation preceded the attack and it
is quite likely that it shared the advantage of surprise common
to a large number of these attacks. Three German regiments were
holding the line directly in front of the British sector concerned.