L.—very light. +—light. ++—normal. +++—heavy. ++++—very heavy. A white cross above these marks means that a plate has been welded on the base. These marks are also painted on the boxes. Shells fitted with cartridge cases (fixed ammunition) are not painted below the rotating bands. Special Shell. Incendiary shells.—These incendiary shells are filled with some flame-producing liquid, alumino thermic charge or incendiary cylinder composed of slow burning linstock and string strongly impregnated with saltpeter. Markings.—Green with red ogive. All shells containing black powder are more or less incendiary. Percussion shrapnel is incendiary. [Illustration: 75-mm Ammunition.] Star Shells.—For 155 howitzer. Upon bursting, they liberate eight white stars fitted with silken parachutes. The stars are projected backward through the base of the projectile at the point of burst. The parachutes open, the stars descending very slowly, illuminating the surrounding objects for about 45 sec. The best height of burst is about 300 m.; the burst interval should not be over 300. These shells are also incendiary. Markings: a blue star and an “E.” Gas shells are either toxic or tear-producing. (a) Toxic shells are numbered either 4 or 5. The liquids 4 and 5 volatize, immediately upon contact with the air. The gases are quickly diffused and easily carried by the wind. Effect.—Liquid 4 acts immediately and is felt instantly. Liquid 5, on the contrary, works more slowly and its effects are apparent only after several hours. Markings: Green with white bands, and numbers 4 or 5 on the ogive. (b) Tear shells.—These shells are numbered 11, 12 and 13. They are filled with two liquids, either mixed or separated, one liquid being tear producing, the other smoke producing. When the shell bursts, a greater part of the liquid is volatilized, the remainder being projected to the ground in small drops which volatize with variable speed. Markings: Green with numbers 11, 12 or 13 on the ogive. Tracer shell.—This shell is fitted with a time fuse which ignites the inside charge, the flames of which pass through the holes in the ogive thus tracing the trajectory. Tracer shells are used in fire for adjustment on aircraft. They are also incendiary. Markings: White with blue ogive. Letter “T” painted on body. PRECAUTIONS IN SEPARATE LOADING PROJECTILES. All projectiles must be seated accurately and carefully in loading, otherwise not only inaccurate fire will result but also premature detonations may occur. Rotating bands should be smoothed and lightly greased just before loading. In transport and in storage the bands should be protected by rope bands, straw tithes, etc., to prevent deformation. CHAPTER XIII CARE AND PRESERVATION. OILS AND CLEANING MATERIAL, TOOLS AND ACCESSORIES FOR ARTILLERY MATERIEL WITH THEIR USE.