Chapter XXII: Part XIV: Miscellaneous

1. What is the velocity of sound in the air?

At the temperature of 33° the mean velocity of sound is 1100 feet in a second. It is increased or diminished _half a foot_ for each degree of temperature above or below 33°.

2. How can the distance of an object be ascertained by the report of fire-arms?

By observing the number of seconds that elapse between the flash and the report of a gun, and multiplying the number by the velocity of sound in the air.

3. What is momentum?

The force possessed by a body in motion; and is measured by the product of the mass of the body into its velocity.

4. When equal masses are in motion, what proportion do their momenta bear to their velocities?

They are proportional to their velocities.

5. When velocities are equal, what proportion do their momenta bear to their masses?

They are proportional to their masses.

6. What proportion do the momenta bear to each other when neither the masses nor velocities are equal?

They are to each other as the products of their masses into their velocities respectively.

7. What is the average weight of a horse?

About 1000 pounds.

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8. What space does a horse occupy in the ranks; in a stall; and at a picket?

In the ranks a front of 40 in., a depth of 10 feet; in a stall; from 3½ to 4½ feet front; at picket 3 feet by 9.

9. What are the comparative effects of the labor of a man, and that of a horse or mule?

Taking the useful effect of a man’s daily labor as unity, a horse can carry a load on a horizontal plane, 4.8 to 6.1 times; and a mule, 7.6 times greater than a man. Taking a man with a wheel-barrow as unity, a horse in a four-wheel wagon can draw 17.5, and in a cart 24.3; and a mule in a cart, 23.3 times greater burden.

10. What weight is an artillery horse required to draw?

Not more than 700 lbs., the weight of the carriage included.

11. What weight can a team of four horses or more, draw with useful effect?

Including the weight of carriage, 4 horses can draw 24 cwt., or 6 each; 6 horses, 30 cwt., 5 each; 8 horses, 36 cwt., 4½ each; and 12 horses, 48 cwt., or 4 each. It is usual to estimate the weight of a carriage exceeding 12 cwt. as part of the load.

12. What weights are carried by the riding, pack, and draught horses respectively?

A horse carrying a soldier and his equipments, (say 225 lbs.) travels 25 miles in a day (8 hours); a pack-horse can carry 250 to 300 lbs., 20 miles a day; and a draught-horse, 1600 lbs. 23 miles a day, weight of carriage included.

13. What are the usual paces for horses in the artillery?

Walk, trot and gallop; the last is seldom necessary.

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14. What is considered an ordinary day’s march for field artillery, and rate of motion?

An ordinary march is about 15 miles at 2½ miles per hour for 6 hours; this must depend upon the condition of the horses, state of the roads, and various other circumstances. Horses starting fresh, and resting after their work, may, on tolerable roads, perform 2 miles in half an hour; 4 miles in 1½ hours; 8 in 4, and 16 in 10 hours.

15. What is the rate of march of horse-artillery and cavalry?

Walk, 3¾ miles per hour, or 1 mile in 16 minutes; trot, 7½ per hour, or 1 mile in 8 minutes; manœuvring gallop, at the rate of 11 miles per hour, or 1 mile in 3 minutes; cavalry charge, 24 miles an hour, or at the rate of 1 mile in 2½ minutes.

16. At what rate does infantry march?

In common time, 90 steps = 70 yards in 1 minute, or 2 miles 680 yards in an hour; in quick time, 110 steps = 86 yards in 1 minute, or 2 miles 1613 yards in an hour; in double quick, 140 steps = 109 yards in 1 minute, or 3 miles 1253 yards in an hour.

17. What space does a foot soldier occupy in the ranks, and what is his average weight?

A front of 20 in., and a depth of 13 in., without the knapsack; the interval between the ranks is 13 in.; 5 men can stand in a space of 1 square yard. Average weight of men, 150 lbs. each.

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18. What is the daily allowance of water for a man?

One gallon, for all purposes.

19. What is it for a horse?

Four gallons.

20. What is the weight of a bushel of oats; or of wheat; and the weight of hay?

40 lbs., or 32.14 lbs. to the cubic foot, in case of oats; 60 lbs. to the bushel, or 48.21 lbs. to the cubic foot, in case of wheat; hay pressed in bundles, weighs 11 lbs. per cubic foot.

21. What weight does an infantry soldier carry when in marching order?

About 45 lbs. in all. His knapsack when packed weighs 24 lbs.; canteen when filled, and one day’s provisions in haversack, 5 lbs.; rifle, musket, sling, and bayonet, 10½ lbs.; belts, complete, including 20 rounds of ammunition, 6 lbs.

22. How is the area of a circle found;

Square the diameter, and multiply by .7854 for the area; or square the circumference, and multiply by .07958 for the same result.

23. How is the content of a conical frustum found?

Add into one sum, the areas of the two ends and the mean proportional between them; take one-third of that sum for the mean area, and multiply it by the perpendicular height of the frustum, for its content.

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24. How is the mean proportional found for the above?

By multiplying the areas of the two ends together and extracting the square root of their product. A more simple rule is the following: As the diameter of the large end is to that of the small end, so is area of base to mean proportional required.

25. How is the content of a spherical segment found?

From three times the diameter of the sphere, take double the height of the segment, then multiply the remainder by the square of the height, and this product by .5236; or, to three times the square of the radius of the segment’s base, add the square of its height, then multiply the sum by the height, and this product by .5236, for the content.

26. How is the capacity or content of a Gomer chamber computed?

This chamber being the frustum of a cone with a hemispherical bottom, its capacity will be found by applying the foregoing rules, viz: first find the content of the frustum, then that of the spherical segment or bottom, and add their contents into one sum for the capacity.

27. How is the content of a rectangular box ascertained?

Multiply the length by the breadth, and this product by the depth.

28. How is the capacity of a cylinder calculated?

Multiply the area of the base by the height.

29. How is the content of a barrel found?

Multiply half the sum of the areas of the two interior circles, taken at the head and bung, by the interior length; or, to the area of the head, add twice the area at the bung, multiply that sum by the length, and take one-third of the product for the content.

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30. What is meant by the term, enfilade?

Sweeping the whole extent of a work, line of troops, deck of a ship, &c., with shot or shells.

31. What does defilade mean?

The art of disposing guns, troops, or works in such a manner, that they shall be protected from a plunging-fire from adjoining heights.

32. What are the dimensions required for an earthen parapet to resist the fire of field or siege guns?

6 feet for 6-pdrs.; 14 feet for 12-pdrs.; 18 feet for 24 or 18-pdrs.; four feet of oak or brick will resist cannon shot.

33. What thickness of ice will admit the passage of infantry, cavalry, and artillery?

Ice 3 inches thick, will bear infantry marching in file; from 4½ to 6½ inches, cavalry and light artillery; and beyond that the heaviest gun carriages may pass in safety. Ice 8 inches thick will bear nearly 10 cwt. upon a square foot without danger.

34. How is the size of a rope designated?

By its circumference: thus, a two-inch rope is a rope two inches in circumference.

35. How is the strength of a hemp rope, or the weight it will support, ascertained?

Square the circumference in inches, and divide by 5, for the weight in tons, that it will bear suspended from it.

36. How can the breadth of a river be ascertained without instruments?

As follows:

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1st. The line _AB_ (the distance to be determined) is extended upon the bank to _D_, from which point, after having marked it, lay off equal distances _DC_ and _Cd_; produce _BC_ to _b_, making _Cb_ = _CB_; then extend the line _db_ until it intersects the prolongation of the line _CA_ at _a_. The distance _ab_ is equal to _AB_ or the width of the river.

2d. Lay off any convenient distance, _BC_, perpendicular to _AB_, erect a perpendicular _DC_ to _AC_, note the point _D_ where it intersects _AB_ produced; measure _BD_; then

__
_BC_²
_AB_ = —————. [3]
_BD_

[3] The 2d method was suggested to me by Captain Vogdes, 1st Artillery, U. S. Army.

37. How can the breadth of a river be ascertained by the means of the peak of a cap, or cocked hat?

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Place yourself at the edge of one bank, and lower the peak of the cap, or point of the hat till the edge cut the other bank, then steady your head, by placing your hand under your chin, and turn gently around to some level spot of ground on your own side of the river, and observe where your peak or point of your hat again meets the ground; measure this distance, which will be nearly the breadth of the river.

38. How do you ascertain the distance of an object by means of the tangent scale of a gun, the height of the object at the required distance being known?

Direct the line of metal of the gun on the top of the object; then raise the tangent slide till the top of it and notch on the muzzle are in line with the foot of the object, and note what length of scale is required; then, by similar triangles, as the length of the raised part of the tangent scale is to the length of the gun, so is the height of the distant object to the distance required.

39. What composition may be used for greasing the axle-trees of artillery carriages?

Hog’s lard softened by working it. If this cannot be procured, tallow or other grease may be used; if hard, it should be melted with fish-oil.

40. What is the simplest method of bursting open strong gates?

Suspend a bag of gunpowder containing 50 or 60 lbs., near the middle of the gate, upon a nail or gimlet, having a small piece of port-fire inserted at the bottom, and well secured with twine.

41. What is the length of a pendulum to vibrate seconds, half and quarter seconds respectively?

Seconds, 39.1 inches; half-seconds, 9.8 inches; and quarter-seconds, 2.45 inches.

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42. Give a formula for determining the length of the seconds pendulum in any latitude.

1
_l_ = ————————— [32.1803 feet - 0.0821 cos. 2 lat.]
9.8696044

43. How are the times of a single oscillation of two pendulums to each other?

As the square roots of their lengths.

44. Repeat the table of measures.

10 tenths, 1 inch.
4 inches, 1 hand.
12 inches, 1 foot.
28 inches, 1 pace.
3 feet, 1 yard.
2 yards, 1 fathom.
220 yards, 1 furlong.
1760 yards, 1 mile.

45. Repeat the table of avoirdupois weight.

47.34735 grains, 1 dram.
16 drams, 1 ounce.
16 ounces, 1 pound.
28 pounds, 1 quarter.
4 qrs. or 112 lbs. 1 cwt.
20 cwt. 1 ton.

In some of our States the ton is estimated at 2000 lbs.

46. What is the force of gravity?

It is that force of attraction exerted by the earth upon all particles of matter which tends to urge them towards its centre.

47. What is the specific gravity of a body?

The ratio of the weight of a body to that of an equal volume of some other body assumed as a standard, usually pure distilled water at a certain temperature.

48. What is the law of descent of falling bodies?

The spaces fallen through from the commencement of the descent are proportional to the squares of the times elapsed.

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49. What compositions are made use of for preserving iron cannon?

1. Black lead, pulverized, 12
Red lead, 12
Litharge, 5
Lampblack, 5
Linseed Oil, 66

Boil it gently about twenty minutes,
during which time it must be
constantly stirred.

2. Umber, ground, 3.75
Gum Shellac, pulverized, 3.75
Ivory black, 3.75
Litharge, 3.75
Linseed Oil, 78
Spirits of turpentine. 7.25

The oil must be first boiled half an hour;
the mixture is then boiled 24 hours,
poured off from the sediment,
and put in jugs, corked.

3. Coal tar (of good quality), 2 gals.
Spirits of turpentine, 1 pint.

In applying lacker, the surface of the iron must be first cleaned with a scraper and a wire brush, if necessary, and the lacker applied hot, in two thin coats, with a paint brush. It is better to do it in summer. Old lacker should be removed with a scraper, or by scouring, and not by heating the guns or balls, by which the metal is injured.

About 5 gallons of lacker are required for 100 field guns and 1000 shot; about 1 quart for a sea-coast gun. Before the lacker is applied, every particle of rust is removed from the gun, and the vent cleared out.

50. How many gallons does a cubic foot contain?

7.48 gallons.

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51. What is the weight of a gallon of distilled water?

At the maximum density (39°.83 Fahr.), the barometer being at 30 inches, it weighs 8.33888 avoirdupois pounds, or 58373 Troy grains.

52. What are the different lengths of plummets for regulating the march of infantry?

Common time, 99 steps in a minute, 17.37 inches.
Quick time, 110 “ “ 11.6 “
Double quick, 140 “ “ 7.18 “

53. How is a plummet made?

By means of a musket ball, suspended by a silk string, upon which the required lengths are marked; the length is measured from the point of suspension to the centre of the ball.

54. Explain how to embark and disembark artillery and its stores.

1. Divide the total quantity to be transported among the vessels, and place in each vessel every thing necessary for the service required at the moment of disembarkation, so that there will be no inconvenience should other vessels be delayed.

2. If a siege is to be undertaken, place in each vessel with each piece of artillery its implements, ammunition, and the carriages necessary to transport the whole or a part; the platforms, tools, instruments, and materials for constructing batteries; skids, rollers, scantling, and plank.

3. If a particular calibre of gun is necessary for any operation, do not place all of one kind in one vessel, to avoid being entirely deprived of them by any accident.

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4. Dismount the carriages, wagons, and limbers, by taking off the wheels and boxes, and, if absolutely necessary, the axle-trees. Place in the boxes the linch-pins, washers, &c., with the tools required for putting the carriage together again. Number each carriage, and mark each detached article with the number of the carriage to which it belongs.

5. The contents of each box, barrel, or bundle, should be marked distinctly upon it. The boxes should be made small for the convenience of handling, and have rope handles to lift them by.

6. Place the heaviest articles below, beginning with the shot and shells (empty), then the guns, platforms, carriages, wagons, limbers, ammunition boxes, &c.; boxes of small arms and ammunition in the dryest and least exposed part of the vessel. Articles required to be disembarked first should be put in last, or so placed that they can be readily got at.

If the disembarkation is to be performed in front of the enemy, some of the field pieces should be so placed that they can be disembarked immediately, with their carriages, implements and ammunition; also the tools and materials for throwing up temporary intrenchments on landing.

7. Some vessels should be laden solely with such powder and ammunition as may not be required for the immediate service of the pieces.

8. On a smooth, sandy beach, heavy pieces, &c., may be landed by rolling them overboard as soon as the boats ground, and hauling them up with sling-carts.

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