Bursting of a shell. The gun is out of sight miles andmiles away

The present war has developed long range guns which can shoot distances undreamed of a few years ago. Most of these guns shoot at unseen targets miles and miles away. Scouting airplanes hover over the enemy's lines and, by noting the location of the bursting shells, give information to the gunners as to whether they are hitting the target. The distance to which shells can be hurled depends upon the length of the gun and the angle of firing. The longer the gun the farther it will shoot. A gun tilted to an angle of 43% degrees will carry a shell to its greatest distance. A shell never travels in a straight line but in a curve, this path being called the trajectory. If the long range gun that has been shelling Paris were fired at an angle of 45% degrees, its shells must have risen to a height of twenty-four miles, which is twenty miles higher than an airplane can rise, owing to the thin air away from the earth. A shell from a large gun leaves the muzzle at the rate of half a mile a second. The larger the diameter of the shell, the greater its speed at the muzzle of the gun, because of the greater surface for the powder gases to press against. But the larger the shell the more it will be retarded by the air. The shells may contain a high explosive, shrapnel or even poisonous gas. A high explosive shell g ives out a succession of black gas clouds. A shrapnel shell contains 250 half-inch balls of lead and is equipped with a time fuse which regulates the explosion so it will occur at a given point, scattering its leaden hail over a wide area. This shell first shows a cloud of white smoke and then a flash of flame