On 5 September the French had 465,000 75mm shells in reserve; by the 10th the reserves had slumped to 33,000. Free to choose their ground, the French gunners had good fields of fire. Employing delayed-action fuses for ricochet fire, a 75mm battery was able to sweep an area of 4 hectares, 400 metres deep, in 40 to 50 seconds. Its four guns, firing ten rounds of shrapnel a minute, discharged 10,000 balls. This was far more effective against advancing infantry than machine-guns.
