"Yes; science is insatiable in its efforts to advance," said Lieutenant D'Arraing. "Here—look through this!"
He swung back the big breech-block, and Don, sighting through the long tube, saw a circular spot of brilliant daylight at the other end.
"You will notice that the inside is rifled," continued the lieutenant. "On the driving band of the projectiles are spiral grooves, which of course exactly coincide with those in the gun, and that is what gives the shell its rotation. Scientific calculations of the density of the atmosphere and pressure of the wind, and the use of trigonometry to find the range all combine to enable the gunners to fire with marvelous accuracy."
"What is your chief work—trying to put the opposing batteries out of commission?" queried Dunstan.
"By no means; though we should not miss an opportunity to do so. The main objective of the artillery, however, is to support the troops, to prepare the way for infantry charges and to prevent the enemy from bringing up supplies and reserves—in fact, to harass them in every way possible."
"This seems to be really a war of big guns," commented Don.
"Quite so!" assented the military man. He laughed. "Now, this is a two-story house. Below, and to one side, is our rest and recreation room. You may take a look if you wish."
The ambulanciers did wish, and a few moments later had clambered down a ladder to a subterranean room many feet underground. Straw was plentifully strewn about the floor, and several of the gun crew were lounging about at their ease.
"A chap doesn't have to bother much about shells in here," said Don.
"No," replied the lieutenant. "As a foundation the roof has iron girders and cement beams. Over these is about a foot of closely-packed earth. Next in order come a number of heavy logs, then earth again. And as a finishing touch there is a second series of logs and a layer of cement, topped off with another generous supply of good old terra firma."