1. Very Pistol Cartridges. The Very pistol cartridges are made in two sizes, a 25-mm size, which is issued to the companies of infantry, and a 35-mm size, which is used by the airplanes. These Very pistols fire both signal and illuminating cartridges. 2. VB Cartridges. The VB cartridges are fired from a cylinder which is attached to the end of a rifle. This cylinder, on account of its resemblance to the old-fashioned blunderbuss (which the French call “Tromblon”) has taken the name of tromblon and now even the VB cartridges, which are fired from this cylinder, are often spoken of as Tromblons. 3. Rockets. The rockets comprise fireworks which are made in the form of cartridges attached to a wooden stick and fired from a tube or trough. They are used both for signaling and illuminating. 4. Flares. Flares are used only in the front lines to mark the position of the advanced troops when called for by an airplane. THE USES OF VARIOUS CLASSES OF FIREWORKS. It will be seen that the above classification of fireworks is an arbitrary one, made according to the method of projecting them. The same signal can be made by several different means. The means employed depend upon the type of fireworks issued to the particular unit using them and also upon the distance through which the signal must be read. Flares are not projected at all and consequently have the most limited range of visibility in any but a perpendicular direction. The 25-mm Very pistol projects its signals about 200 ft. and can be seen from the immediate vicinity. The tromblon projects its signals to a height of 300 ft. and is next in range of visibility. The rockets which project a signal at the height of 1000 ft. or over have the maximum range of visibility. The 35-mm Very pistol projects signals which are larger than those of the 25-mm pistol, but throws them a shorter distance (about 150 ft.). As its use is confined to the airplane this is not a factor in its visibility. The following are important uses that may be made of fireworks: 1. By the infantry platoon, company or battalion commander in signaling to the artillery for a barrage, or otherwise directing the fire of the artillery. 2. For signaling between the front line troops and the contact airplane in an advance. 3. Warning of enemy gas attack given by the fireworks signaler nearest to where the gas is discovered. 4. As a method of acknowledging various visual signals. 5. Occasionally, during the preparation of an attack and upon orders from the General Staff, fireworks may be used in liaison between the artillery and the artillery airplanes. Signaling by Means of Panels. The increasing use of the airplane in modern warfare has necessitated the development of reliable communication between it and the earth. This has gradually been worked out in the following methods: 1. The direct dropping of messages by the airplane. 2. The use of radio apparatus.