Whether air or water cooled, machine guns still jammed frequently, especially in hot conditions or when used by inexperienced operators.
Consequently machine guns would often be grouped together to maintain a constant defensive position.
Estimates of their equivalent, accurate, rifle firepower varied, with some estimating a single machine gun to be worth as many as 60-100 rifles: a more consensual figure is around 80, still a high figure.
Poison gass, Although it is popularly believed that the German army was the first to use gas it was in fact initially deployed by the French. In the first month of the war, August 1914, they fired tear-gas grenades (xylyl bromide) against the Germans. Nevertheless the German army was the first to give serious study to the development of chemical weapons and the first to use it on a large scale. The debut of the first poison gas however - in this instance, chlorine - came on 22 April 1915, at the start of the Second Battle of Ypres.
At this stage of the war the famed Ypres Salient, held by the British, Canadians and French, ran for some 10 miles and bulged into German occupied territory for five miles. A combination of French territorials and Algerian troops held the line to the left, with the British and Canadians tending the centre and line to their right.
During the morning of 22 April the Germans poured a heavy bombardment around Ypres, but the line fell silent as the afternoon grew. Towards evening, at around 5 pm, the bombardment began afresh - except that sentries posted among the French and Algerian troops noticed a curious yellow-green cloud drifting slowly towards their line.
Puzzled but suspicious the French suspected that the cloud masked an advance by German infantry and ordered their men to 'stand to' - that is, to mount the trench fire step in readiness for probable attack.
The cloud did not mask an infantry attack however; at least, not yet.
