Impatience with digging, which was characteristic of the early days of the American Civil War, and which has been generally resented by all armies in the past, has now become second nature to every soldier, because its value is brought home to him by the most telling kind of lesson in experience--death. He puts earth between himself and the enemy's fire as instinctively as one holds up his hand to ward off a blow. In trench fighting all that is exposed of a man firing is his head and shoulders, which accounts for the high percentage of dead to wounded in this war. In other wars it has been as one to five; while in this war, on the western front, it has varied from as one to two and three. If the trenches are brought extremely close together then either side is safe from the other's artillery fire, because there is as much danger of hitting your own trench as the enemy's with your shells. A distance of 20 or 30 yards meant that at any time either side could start in throwing bombs or grenades by hand across that one definitely neutral country--the zone of death between the trenches. Beyond that range up to the average range, trench mortars which "lobbed" a charge of high explosive from trench to trench could be used. Thus the war of machinery became a war of explosives. Anything that could be dropped into the trench and burst might kill or wound some of the enemy, which meant debit on their side of the ledger in a war of attrition and exhaustion. The higher the angle of flight the more likely the charge actually to fall into the narrow ditch in the earth, instead of breaking its force against the wall, which accounts for the superiority of the howitzer with its high angle of flight and shorter range to the gun with its lower trajectory and longer range. Thus there can be no limitation to the amount of artillery and the quantities of explosives serviceable in this kind of warfare. No one of the armies has ever had anything like enough shells. None ever can. Five hundred guns of all ranges set back of one another from 3,000 to 20,000 yards' range to a mile could be placed, or 225,000 for the western front, and they could readily use five million shells a day in this contest of munitions and manufacturing resources. All armies had to conserve their ammunition, and in parts of the line, which were known as "quiet corners," for tactical reasons the stalemate was almost peaceful, either side holding its fire unless the other became restless. But between the trenches which had remained in the same position for many months, no living thing was visible day after day except a rabbit or a field mouse where the ground birds made their nests, and there the piping of birds joined with the song of the bullets. Except for occasional snipers' shots at the sight of anything moving on the enemy's parapet, the day wore monotonously on--when to expose the head for half a minute meant death.