Forward observers in Cuthbert Crater, NE of Arras, April 1917. Observation posts were not always elaborate or safe. This one is at least reasonably dry for the observers and signalers of the 12th (Eastern) Division during the preparations for the battle of Arras. Source: IWM photo Q5095.

55th Siege Battery Royal Australian Garrison Artillery, Voormezeele, 15 September 1917. The 9.2″ howitzer was an excellent weapon with good range and shell power. However, it was not very mobile; the large box at the right was part of the weapon's frame that helped hold it in place. Every time the howitzer was moved it had to be emptied of around nine tons of earth, disassembled, moved, reassembled, and refilled. In 1918, the rough estimate was that these howitzers were of no use if the front moved more than 3,000 yards per day, as the time taken in moving the weapons far outweighed their time in action. These gunners, near the Ypres Salient, are presumably firing a night harassing mission. They are masked against German gas. Gas was commonly used at night because sleeping soldiers were more likely to breathe enough gas to incapacitate or kill them before they could be woken by an alarm. The British used the same logic as well.

Map 9. V Corps barrage map, Cambrai, 20 November 1917. At Cambrai the BEF fired a lifting barrage that moved straight from target to target instead of sweeping all the ground in between lines, as a creeping barrage (MAP 1) did. The smoke barrages shown here were weather-dependent, but the weather was favorable on 20 November and they were fired. However, while they were effective for their duration, that duration had been miscalculated, and German anti-tank fire became effective.

Map 10. Western Front, Allied offensives, 1918. This map shows the outlines of the Allied, including British, offensives in 1918.

Map 1. Planning map for a creeping barrage, Messines Ridge area, June 1917. This map shows the creeping barrage planned for IX Corps (see Map 4) at Messines Ridge. Maps like this would have been distributed to every field artillery brigade involved in the operation.

This shows two shells and two trajectories. "A" shows gun shrapnel, fired with high velocity and flat trajectory. These two factors cause the balls to fan out over a deep but fairly narrow area. Gun shrapnel was highly effective against men in the open, but much less effective against troops in cover or protection. "B" shows howitzer shrapnel coming down from a high trajectory. The arced trajectory limits the area covered by the balls, but also means that the balls can reach behind cover, such as a gunshield or wall. "C" shows high explosive shell penetrating cover. While clearly the most effective in these circumstances, it is also clearly less effective at covering open ground than shrapnel. Source: H. A. Bethell, Modern Artillery in the Field.

Artillery officer issuing orders based on aerial observation, near Montauban, July 1916. This wireless set had an antenna about fifty feet long, the end of which can be seen snaking upwards along the right side of the photo. Due to weight limits, aircraft could only carry transmitters (not transmitters and receivers), and to see when the battery was ready to fire the aircraft had to circle back to see what ground panels had been laid out. Source: IWM photo Q4036.

New Zealand artillerymen loading limbers with ammunition, near Albert, September 1916. Every shell that was fired in World War I was handled many times on its way to the front, requiring a tremendous amount of labor, and usually many loadings and unloadings. This is one of the last stages: loading the limbers that will go forward to the gun positions, where the shells will be unloaded close to the guns. The white crosses on the end of each round are cloth handles that were secured by light metal clips; they simply made it easier to pull the rounds out of the limbers and generally made them easier to handle. Source: IWM photo Q1249.

Map 4: 3. Hollebeke Inset

The 18-pounder was a very modern field gun in 1914, having only been adopted in 1909. The British had not produced enough to equip the Territorial Force with 18-pounders, having to rely on the outdated 15-pounders which did not have full pneumatic recoil. Key: A. Gun tube; B. Recoil guides; C. Cradle; D. Recoil spring case; E. Upper carriage; F. Trail; G. Brake arms; H. Traversing lever; I. Spade; J. Trail eye; K. Elevating screw; L. Rocking bar sight; M. Clinometer; N. Dial sight; O. Firing lever; P. Guard (prevents crewmember from catching arm); Q. Horn connecting gun and buffer; R. Gun shield.

60-pounder firing a barrage, near Moeuvres, dawn of 27 September 1918. After 1916, one of the main uses of 60-pounders was adding depth to the creeping barrage. With greater range than the 18-pounders, the 60-pounders could hit specific targets ahead of the main barrage, to suppress them, restrict the movement of German reserves, or destroy particular targets. On the right horizon a field battery is moving forward, likely to become a direct-support battery or take up an advanced position to fire a later stage of the creeping barrage, something that was possible in 1918 but would have been suicidal in 1917. Source: IWM photo Q9333.

Map 12. Western Front 1915-1916. This map shows the sites of the main battles of 1915 on the Western Front.