Sore backs and galled shoulders are generally occasioned by neglect. The greatest pains will be taken in the fitting of the saddles and collars; the men must never be allowed to lounge or sit unevenly in their saddles. Every driver should keep a pair of soft leather pads, stuffed with hair, about six inches by four; the moment any tenderness is noticed in a horse's shoulder, the pressure is removed by placing these pads under the collar above and below the tender part. DESTRUCTION OF HORSES. Occasions arise rendering the destruction of horses necessary. The following instructions will enable one to arrive at a point directly over the summit of the brain, and which when fired upon will cause instantaneous death. Draw a line, _A A_, horizontally across the forehead from the upper margin of one zygomatic ridge to the other, and from its central point, _B_, measure vertically upward on the forehead 3½ to 4½ inches. The point, _D_, thus obtained is directly over the brain-cavity. [Illustration: FIG. 76.] Before firing, the horse should be induced to lower his head, which is easily accomplished by placing a little food upon the ground, the muzzle of the weapon being brought directly over the spot indicated. It is a mistake to suppose that the star, or curl, is over the brain-cavity, for it is generally below the cavity. CHAPTER VII. Organization of Artillery. Composition of Light Batteries. Equipment. Equipment and Clothing for Marches. Marches. Selection of Camps. Making Camp. Breaking Camp. Allowance of Wagons. ORGANIZATION OF ARTILLERY. Artillery troops are divided into light artillery and heavy artillery. To the light artillery belongs the service of the batteries which manœuvre with troops in the field. The light-artillery batteries include horse-batteries, in which the cannoneers are mounted on horseback; field-batteries, in which the cannoneers march by the side of their pieces, or are mounted on the ammunition-chests, axle-seats, and off horses; and mountain-batteries, in which the pieces may be transported on pack-animals. Machine-batteries are designated, according to their equipment and model of gun, as horse, field, or mountain, Gatling, Gardner, etc., batteries. The 3.2-inch gun is used in both field-and horse-batteries; the 3.6-inch gun is used in field-batteries only. A field-battery equipped with the 3.2-inch gun is called a _light field-battery_; one equipped with the 3.6-inch gun is called a _heavy field-battery_. A battalion of artillery consists of two, three, or four batteries, and is commanded by a field-officer of artillery. The heavy artillery of an army in the field consists of those batteries which serve the siege-and position-guns, and the artillery-ammunition and supply trains. The light artillery of an army corps consists of _divisional artillery_ and _corps artillery_.