Metcalfe gives: horse-artillery, 650 pounds; light field-artillery, 700 pounds; heavy field-artillery, 850 pounds; and siege-artillery, 1000 pounds; and the English Handbook contains the following table giving a rough estimate of what teams may be called upon to transport: -------------------------+---------+---------+---------+---------- |Teams of |Teams of |Teams of |Teams of |4 horses.|6 horses.|8 horses.|12 horses. -------------------------+---------+---------+---------+---------- | Cwt. | Cwt. | Cwt. | Cwt. Horse-artillery batteries|20 to 24 |33 to 36 | | Field-batteries |26 to 30 |39 to 45 |48 to 56 | Batteries of position | | | 70 | 5 tons -------------------------+---------+---------+---------+---------- [Illustration: FIG. 74. _b_, breast-strap; _c_, collar; _d_, double-tree; _s_, single-tree; _t_, trace.] Owing to their interference with each other's motions, the maximum load drawn by teams of horses increases less rapidly than does the number of horses in draught. In horse-artillery teams 6 horses is the greatest number that can be usefully employed; in the heavier field-batteries 8 horses are sometimes used, but not when it can be avoided, as it makes a cumbersome team and a large percentage of the working power of the extra pair is lost. Bad roads, insufficient food, rapid movement for short times, and forced marches require that the weights behind horses should be kept at a minimum consistent with the service required. The average weights exclusive of cannoneers of all the principal military powers are: horse-artillery--gun-carriage, 634 lbs.; caisson, 727 lbs.;[7] and field-artillery--gun-carriage, 718 lbs.; caisson, 796 lbs. GAITS FOR ARTILLERY. The =Manœuvring Gallop= is at the rate of twelve miles an hour (352 yards in a minute). This gait is used on occasions by horse-artillery, and in great emergencies for very short distances by field-artillery. The =Manœuvring Trot= or =Trot-out= is at the rate of eight miles an hour (235 yards in a minute.) The =Canter= is at the same rate, viz., eight miles an hour. The =Slow Trot= is at the rate of from six to six and one half miles an hour, and should be used by light artillery for distances of several miles when necessary to move at a faster gait than a walk. At drills and on road marches it should be considerably employed so that teams may move easily and with unnecessary fatigue when called on to cover long distances rapidly. The =Walk= is at the rate of four miles an hour (117 yards in a minute). It is the pace usually employed on the line of march for field-batteries, although they move, as does horse-artillery, at an alternate trot and walk, covering about five miles an hour. DENTITION.