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.