The Lewis gun was much lighter though no less effective when used properly. It was air-cooled and could therefore not be fired for as long without jamming. Its advantage was that it was light enough to be carried by its operator on an attack, although the gunner had to first lie down and set up a tripod (Fig.8). It was invaluable for holding captured trenches until heavier guns could be brought up.

Although often overshadowed by the machine gun, the artillery were in fact the real killers of the First World War. Two thirds of those dying were killed by artillery. The artillery were huge guns which fired shells at their targets - trenches, soldiers, supplies and the enemy’s artillery, which would often fire back (Figs.1 and 4). Although artillery fire was a major reason for constructing trenches, they did not actually provide much protection to the soldiers squatting in their dugouts.

Artillery was developed to allow faster, longer firing which thus caused greater devastation of targets. Shells also evolved to provide increased accuracy. By the beginning of the war, many guns could fire over thirty kilometres. This ability made them an integral part of the strategy of trench warfare, as explained in the "Tactics and strategies" section. Due to the large number of tasks the artillery had to carry out, different shells were used for different jobs. These shells came in three main varieties:

Shrapnel - This was the most deadly. Shrapnel was invented and used by Sir Henry Shrapnel in nineteenth century India. Shrapnel shells consisted of an explosive charge surrounded by hundreds of small, round iron balls. When detonated these lethal pieces flew in all directions, maiming and killing those in its path. Infantry suddenly vaporised as their bodies were blown to a thousand pieces. They were the lucky ones. Others were disembowelled or mortally wounded, only to die a horrible death as their comrades desperately rushed the injured man to a first aid post. Shrapnel was also used against barbed wire at the Somme, although here it proved less effective

High explosive - This shell was used to destroy fortifications such as the German dugouts. The Germans used them extensively at Verdun against the French forts. Soldiers lived in fear of being buried alive. The blast from the explosion was very powerful however, and many were killed by this alone.

Armour piercing - The third and final variety was originally used by the navy against warships. When tanks were introduced, armour-piercing shells proved to be the best counter-measure.

This type of artillery was perhaps the most hated of weapons, causing huge casualties. Trench mortars were first used by Cumberland’s Forces at Culloden in 1745. Although relatively primitive compared to the main artillery pieces, they were very effective. Mortar shells were fired with a high trajectory and easily slipped into trenches with shocking consequences. The high trajectory meant observant soldiers could see incoming shells, giving a few seconds to decide which way to run. Standard shells, on the other hand, were less likely to arrive in a trench but they gave no warning of their arrival.

Vast quantities of ammunition were required since gunners could fire between fifteen and twenty shots a minute. At the Somme 1.5 million shells were used. Without the help of efficient industry at home, the role of artillery in the war would have been much smaller, and the war would have been far, far harder to win.

Gas first appeared on the Western Front in January 1915 when the Germans used chlorine gas in a minor attack. Its first major use was in April 1915 at Ypres where it caused utter terror amongst the troops.

Chlorine gas was a malevolent new weapon. It was taken up to the trenches in cylinders and released when the wind was blowing towards the enemy. It formed a green cloud, which drifted with the wind. Because the gas was heavier than air, it would quickly fill any holes - trenches or even a shell hole. The gas dissolved in the lungs to form concentrated hydrochloric acid, causing irreversible damage. A British soldier wrote this of a gas attack:

Soon soldiers wanted effective counter measures to this terrifying weapon. Initially, they were left to improvise for themselves. When a chlorine gas cloud began drifting towards his soldiers, a young officer remembered that water filtered out chlorine and advised his men to urinate on their handkerchiefs and breath through them. After several attempts carbon filters and a canvas mask replaced this arrangement. Although very uncomfortable for the wearer, at last an effective counter measure had been found to combat chlorine (Fig.9). The army, ever confident that cavalry could win the war, even developed horse gas masks.