Here’s an section from Instructions for Field Artillery (1860). Found in the chapter on “pointing and range,” this excerpt gives tips for aiming cannons and using projectiles effectively in battlefield situations, particularly against cavalry.
These paragraphs give an example of the details found in the manual and may provide helpful background when considering artillery in Civil War combat. (Spelling, bold, and italics is original.)
Here’s the primary source text, found on pages 41-43:
PRACTICAL HINGS ON POINTING
As it is impossible to point a piece correctly without knowing the distance of the object, artillerymen should be frequently practiced in estimating distances by the eye alone, and verifying the estimate afterwards, either by pacing the distance, or by actual measurement with a tape-line or chain, until they acquire the habit of estimating them correctly.
Shells are intended to burst in the object aimed at: spherical case shot are intended to burst from fifty to seventy-five yards short of it.
Shell or spherical case firing, for long ranges, is less accurate than that of solid shot.
At high elevations a solid shot will range farther than a shell or spherical case shot of the same diameter fired with an equal charge. But at low elevations, the shell or spherical case will have a greater initial velocity, and a longer range. If, however, the charges be proportioned to the weights of the projectiles, the solid shot will in all cases have the longest range.
The velocity or range of a shot is not affected in any appreciable degree by checking the recoil of the carriage, by using a tight wad, or by different degrees of ramming.
The principle causes which disturb the true flight of the projectile may be simply stated as follows:
1st. If the wheels of the carriage are not upon the same horizontal plane, the projectile will deviate toward the lowest side of the carriage.
2nd. If the direction of the wind is across the line of fire, deviations in the flight of the projectile will be occasioned, and in proportion to the strength of the wind, the angle its direction makes with the line of fire, and the velocity of the projectile.
3rd. If the centre of gravity of the projectile be not coincident with with the centre of figure, the projectile will deviate toward the heaviest side, that is, in the same direction that the centre of gravity of the projectile, while resting in the place, lies with regard to the centre of the figure. Therefore, if the shot be placed to the piece so that its centre of gravity is to the right of the centre of the ball, the shot will deviate toward the right; and vice versa. If the centre of gravity be above the centre of figure, the range will be increased; if below, it will be diminished.
Should the enemy’s cavalry be at a distance of 1000 yards from the battery it is about to charge, it will move over the first 400 yards at a walk, approaching to a gentle trot, in about four and half minutes; it passes over the next 400 yards at a round trot in a little more than two minutes; and over the last 200 yards at a gallop, in about half a minute, the passage over the whole distance requiring about seven minutes. This estimate will generally be very near the truth, as the ground is not always even, nor easy to move over. Many losses arise from the fire of the artillery and from accidents, and the forming, and filling up of intervals create disorder; all of which contribute to retard the charge. Now a piece can throw with sufficient deliberation for pointing two solid shot or three canisters per minute. Each piece of the battery, therefore, might fire nine rounds of solid shot upon the cavalry whilst it is passing over the first 400 yards; two rounds of solid shot and three of canister whilst it is passing over the next 400 yards; and two rounds of canister whilst passing over the last 200 yards – making a total from each gun of eleven round shot and five canisters. To this add the fire of the supporting infantry.
Care should be taken not to cease firing solid shot too soon, in order to commence with canister. If the effect of the latter be very great on hard, horizontal, or smooth ground, which is without obstruction of any kind, it is less in irregular and soft ground, or on that covered with brushwood; for, if the ground be not favorable, a large portion of the canister shot is intercepted. A solid shot is true to its direction, and, in ricochet, may hit the second line if it misses the first.
Solid shot should be used from 350 yards upwards: the use of canister should begin at 350 yards, and the rapidity of the fire increase as the range diminishes. In emergencies, double charges of canister may be used at 150 or 160 yards, with a single cartridge.
Spherical case ought not, as a general rule, to be used for a less range than 500 yards; and neither spherical case or shells should be fired at rapidly advancing bodies, as for instance, cavalry charging.
The fire of spherical case and of shells on bodies of cavalry in line or column, and in position, is often very effective. To the destructive effects of the projectiles are added the confusion and disorder occasioned amongst the horses by the noise of their explosion; but neither shells or spherical case should be fired so rapidly as solid shot.
In case of necessity, solid shot may be fired from howitzers.
[End of section]
Instruction for Field Artillery, 1860, RB 107441, The Huntington Library,
San Marino, California. Link to record.