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 * f 
 
 COURSE OF INSTRUCTION 
 
 IN 
 
 ORDNANCE AND GUNNERY: 
 
 COMPILED FOR THE USE OF THE 
 
 CADETS 
 
 OF THE 
 
 UNITED STATES MILITARY ACADEMY. 
 
 Capt. J. G. BENTON, Oed. Dept., 
 
 LATE INSTRUCTOR OF ORDNANCE AND SCIENCE OF GUNNERY, MILITARY ACADEMY, WEST POINT, 
 PRIN. AS9T. TO TIIE CHIEF OF ORDNANCE, U. S. A. 
 
 SECOND EDITION, REVISED AND ENLARGED. 
 
 or thc 
 UNIVERSITY 
 
 ^LlfORH^y KEW YORK: 
 
 D. VAN NOSTRAND, 192 BROADWAY. 
 1862. 
 

 v 
 
 1 
 
 pK 
 
 Entered according to Act of Congress, in the year 1 862, 
 
 By D. VAN NOSTRAND, 
 
 In the Clerk's Office of the District Court of the United States for the 
 Southern District of New York. 
 
 C. A. AI.VORD, KLECTROTYPER AND PRINTER. 
 
A large portion of the matter contained in the following 
 pages, and particularly that which relates to the " Effects of 
 Gunpowder'' and the " Motion of Projectiles in fire-arms" 
 is taken from Piobert's Cours oV Artillerie. 
 
 70 
 
CONTENTS. 
 
 CHAPTER I. Page. 
 
 Gunpowder 7 
 
 CHAPTER II. 
 Projectiles 71 
 
 CHAPTER III. 
 Cannon 104 
 
 CHAPTER IV. 
 Artillery Carriages 212 
 
 CHAPTER Y. 
 Machines and Implements 248 
 
 CHAPTER YI. 
 Small-Arms 270 
 
 CHAPTER YII. 
 Ptrotechny 342 
 
 CHAPTER YIII. 
 Science of Gunnery . 382 
 
 CHAPTER IX. 
 Loading, Pointing and Discharging Fire- Arms 435 
 
 CHAPTER X. 
 Different Kinds of Fires 450 
 
 CHAPTER XL 
 Effects of Projectiles 471 
 
 CHAPTER XII. 
 Employment of Artillery 488 
 
 CHAPTER XIII. 
 
 Tables of Multipliers 505 
 
 Tables of Fire 516 
 
 APPENDIX. 525 
 
 INDEX 537 
 
ORDNANCE AND GUNNERY. 
 
 PART I. 
 
 ee £ 
 
 CHAPTER I. 
 
 GUNPOWDER. 
 
 1. General theory. Gunpowder and the compositions 
 of pyrotechny are the means used, in modern warfare, 
 to propel projectiles, explode mines, destroy ships and 
 buildings, and furnish light and signals for the opera- 
 tions of an army at night. They are simply mechanical 
 mixtures of substances which give out light, heat, and 
 gas in their combustion, or chemical union with each 
 other. 
 
 The two classes of substances generally used for these 
 purposes are the nitrates and chlorates on one hand, and 
 charcoal, sulphur, antimony, &c, on the other. The 
 former class contains a large amount of oxygen, which 
 is a strong supporter of combustion ; and the latter em- 
 braces those substances which have a powerful affinity 
 for it. 
 
 Explosion is a phenomenon arising from the sudden 
 enlargement of the volume of a body, as in the case of 
 combustion, when a solid body is rapidly converted 
 into one of vapor or gas. If this change of state be 
 
 t 
 
8 GUNPOWDER. 
 
 accompanied by the development of a large amount of 
 heat, the explosive effect will be very much increased. 
 
 Gunpowder is an explosive substance, formed by the 
 mechanical mixture of nitrate of potassa, sulphur, and 
 charcoal. 
 
 The parts performed by these ingredients in the ex- 
 plosion will be best understood by an examination of 
 the following table : 
 
 COMPOSITION OF GUNPOWDER. 
 
 AFTE] 
 
 3 carbonic acid (gas). 
 
 BEFORE COMBUSTION. AFTER COMBUSTION. 
 
 3 parts of carbon, 3 carbon, 
 
 6 oxygen, 
 1 part of nitrate of potassa, -J 1 nitrogen, 1 nitrogen (gas). 
 
 •<ii 
 
 potassium, 
 
 1 part of sulphur, 1 sulphur, 
 
 \ 1 sulphide of potassium (solid). 
 
 A gunpowder can be made of nitrate of potassa and 
 charcoal alone; but it is not so strong as when sul- 
 phur is present ; besides, the substance of the grain is 
 friable, has considerable affinity for moisture, and rapidly 
 fouls the arms in which it is used. 
 
 Theoretically, sulphur does not contribute directly to 
 the explosive force of gunpowder by furnishing materi- 
 als for gas ; but, by uniting with the potassium, it affords 
 a large amount of heat, and prevents the carbonic acid 
 from uniting with the potassa and forming a solid com- 
 pound — the carbonate of potassa. It is to the heat and 
 carbonic acid thus formed that gunpowder mainly owes 
 its explosive force. 
 
 The strength of gunpowder, or amount of work which 
 a certain quantity is capable of performing in a given 
 time, depends on the mass of the powder and the veloc- 
 ity with which its gaseous particles are evolved. 
 
 t 
 
SALTPETRE. 9 
 
 This velocity of evolution of the gaseous particles, or 
 " quickness," depends on the purity, proportion, and in- 
 corporation of the ingredients, and on the size, form, 
 and density of the grains. These will be discussed in 
 the following pages, under the heads of Materials, Fab- 
 rication, Mechanical Effects, and Chemical Properties 
 of gunpowder. 
 
 MATERIALS. 
 
 SALTPETKE. 
 
 2. Description. Saltpetre, nitre, or nitrate of potassa, 
 is composed of 53.45 of nitric acid, and 46.55 of potas- 
 sa, or KO+JSTO$. It crystallizes in colorless six-sided 
 prisms ; has a cooling, saline, and slightly bitter taste, 
 and deflagrates with more violence than any other 
 nitrate when thrown on burning charcoal. It is an- 
 hydrous ; but its crystals often contain water mechan- 
 ically confined. It is not deliquescent in common air 
 (a very important quality in an ingredient of gunpow- 
 der), but is so in an atmosphere nearly saturated with 
 moisture. It is insoluble in the oils and pure alcohol. 
 
 It is decomposed when strongly heated, and oxygen 
 is evolved at first ; finally nitrogen is given off, and per- 
 oxyde of potassium remains. When heated with com- 
 bustible materials, nitre is completely deprived of its 
 oxygen ; it is consequently much used as an oxydizing 
 agent. This is the part which it plays in gunpowder. 
 
 The solubility of nitre increases rapidly with the tem- 
 perature. 
 
 100 parts of water at 32° dissolve 13.32 of nitre. 
 " " " 64.4° " 29.00 " 
 
 " " " 113° " 74.00 " 
 
 M m u 212 o u 246.15 " 
 
10 GUNPOWDER. 
 
 Hence, a hot saturated solution, on cooling, deposits 
 the greater portion of the salt which had dissolved. 
 
 3. Sources. Nitrate of potassa, in connection with 
 more or less of the nitrates of lime and magnesia, is ob- 
 tained from several sources, among which may be enu- 
 merated calcareous caves, certain soils in warm climates, 
 artificial nitre beds, and the mortar of stables or other 
 buildings long occupied by animals, in which cases it 
 generally occurs as an efflorescence. It is also found in 
 the tobacco, sunflower, beet-root, cornstalk, and other 
 plants. 
 
 The caves occurring in certain porous limestones are 
 often found to contain large quantities of the nitrates of 
 lime, potassa, and magnesia, deposited in the loose ma- 
 terials at the bottom, efflorescing from the sides, or even 
 contained in the pores of the rock itself. Many of the 
 limestone caves in Kentucky, Virginia, Tennessee, <fcc, 
 abound in nitrates. In Madison county, Kentucky, 
 there is a cave 1,936 feet long by 40 wide, which con- 
 tains the nitrates of potassa and lime, mingled with the 
 earthy matter at the bottom. One bushel of the earth 
 yields, by double decomposition with carbonate of po- 
 tassa, from three to ten pounds of nitre. 
 
 The greater part of the nitre used in England, and 
 this country, is derived from the soil in various parts of 
 the East Indies. It occurs in the same manner in vari- 
 ous warm countries, as Egypt, Spain, &c. In the vicin- 
 ity of Monclova, Mexico, it occurs in veins, or mines, in 
 a state of great purity. 
 
 It appears to be generated spontaneously at the depth 
 where the soil retains its moisture ; and when dissolved 
 by rains, the subsequent evaporation, by capillary at- 
 
SOUKCES OF NITEE. 1L 
 
 traction, causes it to rise to the surface, where it is de- 
 posited as a crust. 
 
 To obtain nitre from this source, the earth is removed 
 to a certain depth, and treated with water, which dis- 
 solves the soluble salts. The solution is then transfer- 
 red to large reservoirs, when it soon evaporates by solar 
 heat, and deposits large crystals of nitre. This is 
 known in commerce as rough, or crude saltpetre. The 
 mother waters are rejected; but as they contain a large 
 quantity of the nitrates of lime and magnesia, they 
 might still afford some nitre if they were mixed with 
 salts of potassa. 
 
 In the north of Europe, where nitre does not occur 
 as a natural product, various artificial processes have 
 long been employed to obtain it ; and similar methods 
 were much used in France during the Revolution, when 
 that country could not be supplied from Spain and 
 other countries. The nitre-beds were mostly used. 
 
 Nitre-beds. These were made by placing loosely on 
 a floor of wood or clay, a layer, of three or four feet 
 thick, of a mixture of earth, calcareous matter — such as 
 marls, calcareous sands, mortar from stables, &c, and 
 various animal products — such as blood, urine, stable 
 manure, &c. Vegetable matter was found to be useful, 
 probably furnishing potassa. The whole was placed 
 under a shed, and occasionally moistened with addi- 
 tional quantities of blood or urine, and in about two 
 years it was fit for lixiviation. In Prussia, the materials 
 are placed in parallel walls about seven feet high, and 
 three or four feet thick, which arrangement is found to 
 be more convenient, and to occupy less space than 
 the beds. 
 
12 GUNPOWDER. NITRE. 
 
 Mortar exposed to decomposing animal matter, in 
 moist, warm places, becomes considerably charged with 
 nitrates. In consequence, the mortar in old stables is 
 often found to be rich in nitrates, and may be used to 
 obtain nitre directly, or it may be advantageously 
 mixed with the materials for nitre-beds. 
 
 The lye of nitrified substances contains nitrate of 
 potassa, but especially nitrates of lime and magnesia; 
 and also chlorides of sodium and calcium. The nitrates 
 of lime and magnesia may be converted into nitrate of 
 potassa by means of the carbonate of potassa ; but on 
 account of the increased value of this substance, the 
 process now generally adopted is as follows, viz. : first, 
 the nitrates of lime and magnesia are converted into 
 the nitrate of soda, by means of the sulphate of soda, 
 and then by the chloride of potassium, the nitrate of 
 soda is converted into the nitrate of potassa. 
 
 The nitrate of potassa thus obtained, like that ob- 
 tained from the soils of warmer climates, is called rough 
 saltpetre, and contains from 15 to 25 per cent, of foreign 
 matter, principally chlorides of sodium and potassium. 
 These are separated by the process of refining. 
 
 4. Refining. The refining of nitre is founded on its 
 rapidly-increasing solubility with elevation of tempera- 
 ture, while the solubility of the chlorides of sodium and 
 potassium is nearly uniform. (For the details of this- 
 process see Ordnance Manual.) 
 
 If, after nitre has been refined, it be desired to pre- 
 serve it for future use, it is fused in iron pots, and cast 
 into cakes weighing about seventy pounds. This method 
 has the advantage of reducing its volume, and expelling 
 the water of crystallization ; but it requires a little 
 
TEST OF PURE SALTPETRE. 
 
 more work to pulverize it afterward in making gun- 
 powder. 
 
 As the United States are in a great measure depen- 
 dent on the East Indies for this important material of 
 war, it has been the policy of the government to pur- 
 chase yearly a certain quantity of rough saltpetre, refine 
 and fuse it, and store it away in the arsenals for future 
 use. The quantity now on hand in the arsenals 
 amounts to several millions of pounds. 
 
 5. Tests. The test of rough saltpetre is founded on 
 the fact that a solution of nitrate of potassa, saturated 
 at a certain temperature, may be left in contact with an 
 additional quantity of saltpetre at the same tempera- 
 ture, without sensibly dissolving any of it ; while under 
 the same circumstances it can dissolve sea salt, and 
 many other soluble salts. 
 
 To a pound of rough saltpetre add a pint of water, 
 saturated with pure saltpetre ; stir the mixture for ten 
 minutes with a glass rod, and decant the liquor on a 
 filter; wash the saltpetre a second time in the same 
 manner, with half a pint of the saturated solution, and 
 pour the whole on the filter ; let it drain, and then dry 
 it perfectly by placing it first on a bed of some absor- 
 bent matter, such as ashes or lime, and then by evapora- 
 tion in a glass vessel over a gentle fire. The saturated 
 solution having taken up only the foreign salts, what 
 remains on the filter (allowing two per cent, for earthy 
 matter and the saltpetre left by the saturated water), 
 is the quantity of pure saltpetre contained in the pound 
 of rough. As the changes of temperature during the 
 operation may affect the quantity of pure saltpetre re- 
 maining on the filter, it is proper to perform a corre- 
 
14 GUNPOWDER. CHLOEATE OF POTASS A. 
 
 sponding operation at the same time and under the 
 same circumstances, on a like quantity of pure salt- 
 petre ; the gain or loss thus ascertained will show the 
 correction to be made in the former result. 
 
 Test of pure saltpetre. For powder, saltpetre should 
 not contain more than l-3000th of chlorides. To test 
 this, dissolve 200 grains of saltpetre in the least possi- 
 ble quantity (say 1,000 grains) of distilled water ; pour 
 on it 20 grains of the solution of nitrate of silver, 
 containing 10 grains of the nitrate to 1,033 grains of 
 water, that being the quantity required to decompose 
 200-3000ths of a grain of muriate of soda ; filter the 
 liquid and divide it into two portions ; to one portion 
 add a few drops of the solution of the nitrate of silver; 
 if it remains clear, the saltpetre does not contain more 
 than l-3000th of muriate of soda ; to the other portion 
 add a small portion of the solution of the muriate of 
 soda ; if it becomes clouded, the saltpetre contains less 
 than l-3000th. By using the test liquor in very small 
 quantities, the exact proportion of muriate of soda may 
 be ascertained. At the refinery of Paris it does not 
 exceed l-18,000th of the saltpetre; and this degree of 
 purity is attained also at the refinery of Messrs. Du- 
 pont. Saltpetre for the best sporting powder is refined 
 a second time, and contains not more than l-60,000th 
 part of chlorides. 
 
 6. Chlorate of Potassa. Other oxydizing substances, 
 such as the chlorate of potassa and nitrate of soda, may 
 be used in the manufacture of gunpowder ; but for this 
 purpose, they are inferior to the nitrate of potassa. The 
 chlorate of potassa is a substance which parts with its 
 oxygen easily, and makes a powder, which has been 
 
NATURE OF CHARCOAL. 15 
 
 found by experience, to give at least double the range 
 with the mortar eprouvette, of that made with nitrate 
 of potassa, but from its great quickness, resembles the 
 fulminates in its destructive effects on the gun. Besides, 
 it is more costly than nitrate of potassa, renders the 
 powder liable to explode by slight causes, and gives a 
 residue which rapidly corrodes iron. 
 
 Its use in the laboratory is chiefly confined to the 
 preparation of colored fires and cannon primers. 
 
 The nitrate of soda is found as an extensive deposit 
 in the soils of some portions of Peru and northern 
 Mexico. It is cheaper than nitrate of potassa, and for 
 the same weight affords a greater amount of nitric acid, 
 or oxygen. Its affinity for moisture constitutes a serious 
 objection to its use in the manufacture of a gunpowder 
 for war purposes, or one that is to be preserved for 
 any length of time. 
 
 The nitrate of soda may be used in obtaining the 
 nitrate of potassa by decomposing it with carbonate of 
 potassa — the potash of commerce. 
 
 CHARCOAL. 
 
 7. Nature of charcoal. Charcoal is the result of 
 the incomplete combustion or distillation of wood. Its 
 composition and properties vary with the nature of the 
 wood, and mode of distillation employed. 
 
 Charcoal obtained from light wood is the best for 
 gunpowder, as it is more combustible and easy to pul- 
 verize, and contains less earthy matters. 
 
 Willow and poplar are used for this purpose in the 
 United States, and the black alder in Europe. The 
 wood must be sound, and should not be more than three 
 
16 GUNPOWDER. CHARCOAL. 
 
 or four years old, and about one inch in diameter; 
 branches larger than this should be split up. It is cut 
 in the spring, when the sap runs freely, and is imnie" 
 diately stripped of its bark. The smaller branches are 
 used for fine sporting powder. 
 
 The operation of charring may be performed in pits, 
 but the method now almost universally used in making 
 charcoal for gunpowder is that of distillation. For this 
 purpose the wood is placed in an iron vessel, generally 
 of a cylindrical form, to which a cover is luted; an 
 opening with a pipe is made to conduct off the gaseous 
 products, and the wood is thus exposed to the heat of 
 a furnace. The progress of distillation is judged of by 
 the color of. the flame and smoke, and sometimes by 
 test-sticks, which are introduced through tubes prepared 
 for the purpose. 
 
 8. Properties. The charcoal thus obtained should 
 retain a certain degree of elasticity, and should have a 
 brown color, the wood not being entirely decomposed ; 
 it retains the fibrous appearance of the wood, and the 
 fracture is iridescent. As it readily absorbs l-20th 
 of its weight of moisture, which diminishes its inflam- 
 mability, it should be made only in proportion as it is 
 required for use. Wood generally contains 52 per cent, 
 of carbon, but distillation furnishes not more than 30 to 
 40 per cent, of charcoal. 
 
 The specific gravity of charcoal triturated under 
 heavy rollers, is about 1-380 ; but in sticks, as it comes 
 from the charring cylinders, it rarely exceeds .300. 
 
 The properties of charcoal vary much with the 
 temperature employed in the preparation. If wood be 
 merely heated until it ceases to give off vapor, a true 
 
ACCIDENTS. 
 
 17 
 
 charcoal is obtained ; but by raising the temperature 
 to redness or whiteness, its properties will be much 
 changed, as is shown in the following table : 
 
 1 
 
 When not heated to 
 redness. 
 
 Heated to redness Heated to whiteness. 
 
 For electricity, 
 
 " heat. 
 Combustibility. 
 
 Non-conductor. 
 Very bad conductor. 
 Easy. 
 
 Good conductor. 
 Good conductor. 
 Less easy. 
 
 Excellent conductor. 
 Excellent conductor. 
 Difficult. 
 
 If sufficient heat be applied to drive off all the vola- 
 tile matters in six hours, a black charcoal, containing 
 from 28 to 33 per cent, of carbon, will be obtained. If 
 the heat be reduced so as to prolong the distillation to 
 twelve hours, the charcoal will have a yellowish brown 
 color, and will contain from 38 to 40 per cent, of car- 
 bon. 
 
 Charcoal inflames at about 460° Fahrenheit. A 
 black coal strongly calcined takes fire quickly, but is 
 easily extinguished. A brown charcoal takes fire 
 slowly, but burns strongly and rapidly. As it is desir- 
 able to have charcoal for gunpowder very combustible, 
 it must therefore be prepared at a low temperature, and 
 must be light. In distillation, the heat is kept below 
 redness. 
 
 9. Accidents. When recently prepared charcoal is 
 pulverized and laid in heaps, it is liable to absorb oxy- 
 gen with such rapidity as to cause spontaneous combus- 
 tion. This has been the cause of serious accidents at 
 powder-mills; and hence it is important not to pul- 
 verize charcoal until it has been exposed to the air for 
 several days. In Prussian powder-mills, pulverized 
 
15 GUNPOWDER. CHAECOAL. 
 
 charcoal is kept in a fireproof room, in iron vessels, as 
 a precaution against accidents. 
 
 When charcoal has not absorbed moisture, and is 
 mixed with oxydizing substances, it may be inflamed 
 by violent shocks, or by friction. This is the principal 
 cause of the accidents which occur in the preparation 
 of explosive mixtures which contain charcoal. 
 
 10. Combustibility. For the purpose of comparing 
 the combustibility of charcoals made of different mate- 
 rials, a certain quantity of each is thoroughly mixed 
 with nitre, in the proportion of 1 part of the former to 
 5 of the latter, and driven compactly into an iron tube 
 about .25 inches in diameter; the weight and length of 
 the filled tube are taken, and the duration of the com- 
 bustion is ascertained by a pendulum or chronometer. 
 The length of composition burned in a second of time 
 is called the velocity of combustion, and is taken as the 
 measure of the combustibility of that particular kind 
 of charcoal. The amount of residue is ascertained by 
 subtracting the weight of the tube and residue after 
 burning from that of the filled tube before burning, 
 and again subtracting this difference from the weight 
 of the composition originally in the tube. The velocity 
 of combustion is independent of the diameter of the 
 tube and of the material of which it is made ; but it 
 varies slightly with the pressure used in driving the 
 composition, and very much with the degree of tritura- 
 tion of the materials. The following tables contain 
 some of the results thus obtained, viz. : 
 
COMBUSTIBILITY OF CHAKCOAL. 
 
 19 
 
 60 parts of nitre and 12 of charcoal. 
 Black Charcoals. 
 
 Velocity of com- 
 bustion. 
 
 Percentage of 
 residue. 
 
 Charcoal of Hemp, 
 
 .31 inch. 
 
 16.6 
 
 " Grape Vine, . 
 
 .26 " 
 
 27.7 
 
 Pine,. 
 
 .18 « 
 
 41.6 
 
 " Black Alder, . 
 
 .16 " 
 
 33.3 
 
 " Spindle Tree, . 
 
 .15 " 
 
 37.5 
 
 " Hazel, . 
 
 .13 " 
 
 41.6 
 
 " Chestnut, . 
 
 .14 " 
 
 50.0 
 
 " Walnut, 
 
 .11 " 
 
 45.8 
 
 Coke. 
 
 .06 " 
 
 62.5 
 
 " Sugar, . 
 Charcoal made by distilling Black 
 Alder, and conducted so as to 
 
 .04 " 
 
 66.6 
 
 give, 
 For 100 p'ts wood, 40 p'ts charcoal, 
 
 .14 inch. 
 
 39.0 
 
 " il 30 " 
 
 .16 " 
 
 37.0 
 
 25 «* 
 
 .15 " 
 
 33.3 
 
 " " 15 " 
 
 .12 " 
 
 35.0 
 
 The following table shows the influence of trituration 
 lcI proportion of ingredients : 
 
 Mixture. 
 
 Parts of 
 
 charcoal 
 
 t.» 60 of 
 
 nitre. 
 
 Charcoal made of Hemp. 
 
 Charcoal made of Pine. 
 
 6 hours 1 trituration. 
 
 4 hours' trituration. 
 
 6 hours' 
 trituration. 
 
 4 hours' 
 trituration. 
 
 Velocity. 
 
 Perct. of 
 residue. 
 
 58.0 
 45.0 
 16.6 
 13.0 
 12.0 
 11.0 
 
 Velocity. 
 
 Pr. ct of 
 residue. 
 
 Velocity. 
 
 Velocity. 
 
 1 
 
 8 
 ! 
 7 
 1 
 6" 
 1 
 5 
 JL 
 4 
 1 
 3 
 1 
 2 
 
 si- 
 io 
 
 12 
 15 
 20 
 30 
 60 
 
 .10 in. 
 
 .12 
 
 .31 
 
 .39 
 
 .56 
 
 .65 
 
 .14 
 
 .08 in. 
 .10 
 
 .17 
 
 .27 
 
 55.0 
 43.0 
 26.0 
 17.0 
 
 .09 in. 
 
 .15 
 
 .18 
 
 .35 
 
 .39 
 
 .59 
 
 .07 in. 
 
 .09 
 
 .12 
 
 .20 
 
 .27 
 
 .53 
 
20 GUNPOWDER. SULPHITE. 
 
 SULPHUR. 
 
 11. Properties. Pure sulphur is of a citron-yellow 
 color, and shining fracture ; it crackles when pressed in 
 the hand. The specific gravity of native sulphur is 
 2.033; that of sulphur refined by sublimation 1.900; 
 its specific gravity is diminished by trituration. When 
 heated, it melts at 226° into a thin, amber-colored liquid; 
 if the temperature be then raised to about 400° it be- 
 comes dark and thick; but if heated still further, up to 
 601°, its boiling point, it becomes again thin and limpid. 
 It begins to pass off in vapor at 115°, and if heated 
 rapidly, inflames at 370°. It is insoluble in water, but 
 soluble in oils and slightly so in alcohol. 
 
 Sulphur is generally found in great quantities in the 
 neighborhood of volcanoes; it may also be obtained 
 from metallic ores (pyrites) and other sources. Most 
 of that used in the United States comes from Sicily 
 through the French refineries. 
 
 Crude sulphur, as extracted by the first sublimation 
 from the ore, contains about 8 per cent, of earthy mat- 
 ter. It is purified by a second sublimation, from which 
 it is collected in the form of powder, called the flowers 
 of sulphur j or, it is melted and run into moulds, mak- 
 ing roll brimstone. It may be also refined, but not so 
 thoroughly, by being simply melted and skimmed. 
 
 Pure sulphur is entirely consumed in combustion; 
 and its purity is thus easily tested by burning about 
 100 grains in a glass vessel; the residue should not ex- 
 ceed a small fraction of a grain. 
 
MANUFACTURE 21 
 
 MANUFACTURE OF GUNPOWDER. 
 
 12. Proportions of ingredients. 
 
 Nitre. Charcoal. Sulphur 
 
 By the atomic theory, . . 74.64 13.51 11.85 
 
 (NOi+KO) + sa+ '-& 
 
 In the United States: 
 For military service, . . . 76.00 14.00 10.00 
 For blasting and mining, . 62.00 18.00 20.00 
 
 The proportions of the ingredients of the earliest 
 gunpowder known, differ but slightly from those now 
 in use; and these, it will be seen, nearly agree with 
 those called for by the theory of combining equivalents. 
 
 For the general purposes of artillery, slight varia- 
 tions in the proportions of the ingredients for powder 
 are not found to affect its strength; but for blasting or 
 mining purposes, a slower powder is found to answer 
 nearly as well as a quick one, consequently the propor- 
 tion of nitre is reduced much below that of gunpowder. 
 Blasting powder is thus made cheap; but as it leaves a 
 large amount of residuum, it cannot be advantageously 
 used in fire-arms. 
 
 13. Operations. The several operations of fabrica- 
 ting gunpowder are: 
 
 1st. Pulverizing ; which consists in reducing the 
 ingredients to finely divided dust. 
 
 2d. Incorporating; which consists in bringing the 
 particles of this dust into such intimate contact that 
 each particle of powder shall be composed of one of 
 each of the ingredients. 
 
 3d. Compressing ; which gives strength and density 
 to the substance of the powder, by converting the in* 
 
22 GUNPOWDER. MANUFACTURE. 
 
 corporated mixture into a cake which 'will not crumble 
 in transportation. 
 
 4th. Graining ; which breaks up the cake into small 
 fragments or grains, and increases the surface of com- 
 bustion. 
 
 5th. Glazing ; which hardens the surface, to protect 
 it from the action of moisture, and rounds the sharp 
 angles of the grains to prevent the formation of dust 
 in transportation. 
 
 6th. Drying; which frees the powder from the 
 moisture introduced in certain operations of the fabri- 
 cation. 
 
 7th. Dusting ; which frees it from the dust, which 
 would otherwise fill up the interstices and retard the 
 inflammation of the charge. 
 
 The proportions of the ingredients, as well as the 
 art of making gunpowder, vary in different countries, 
 and even among the different manufactories of the same 
 country. 
 
 The variations in the proportions are slight, how- 
 ever, and the differences in the modes of manufacture 
 are principally confined to the more important opera- 
 tions of pulverizing, mixing, and conrpressing the com- 
 position. For French military powder, these operations 
 are performed in the "pounding-mill," or a series of 
 mortars and pestles. In Prussia the composition is 
 pressed into cake by passing it between two heavy rol- 
 lers, by means of an endless band of cloth, which re- 
 ceives the dust from a hopper. In England these 
 operations are performed by the "rolling-barrel," "cyl- 
 inder-mill," and "press." The superior strength and 
 excellent preservative qualities of the English powder 
 
MANUFACTURE. 23 
 
 have led to the adoption of this mode of manufacture 
 in the United States. 
 
 14. Proce§§e§ of manufacture.* The buildings in 
 which the different operations are carried on are sepa- 
 rated from each other, and protected by trees or trav- 
 erses as far as practicable. 
 
 Pulverizing. The saltpetre is usually pulverized 
 sufficiently when it comes from the refinery. The char- 
 coal is placed in large cast-iron barrels with twice its 
 weight of zinc balls. The barrel has several ledges on 
 the interior, and is made to revolve from 20 to 25 times 
 in a minute. It is pulverized in 2 or 3 hours. The 
 sulphur is placed in barrels made of thick leather 
 stretched over a wooden frame, with twice its weight of 
 zinc balls from*3 to^ inches in diameter, and the barrel 
 made to revolve about 20 times per minute. It takes 
 one hour to pulverize the sulphur. 
 
 Incorporating. The ingredients having been weigh- 
 ed out in the proportions above given, the charcoal and 
 sulphur are put together in a rolling-barrel similar to 
 that in which the sulphur is pulverized, and rolled for 
 one hour. The saltpetre is then added, and rolled for 
 three hours longer. In some mills this operation is 
 omitted. It is now taken to the cylinder, or rolling- 
 mill. This consists of two cast-iron cylinders rolling 
 round a horizontal axis in a circular trough of about 4 
 feet diameter, with a cast-iron bottom. The cylinders 
 are 6 feet in diameter, 18 inches thick on the face, and 
 weigh about 8 tons each. They are followed by a 
 wooden scraper, which keeps the composition in the 
 centre of the trough. 
 
 * Vide Ordnance Manual. 
 
24 GUNPOWDER. MANUFACTURE. 
 
 A charge of 75 lbs. in some mills, and 150 lbs. in 
 others, is then spread in the trough of the rolling-mill, 
 and moistened with 2 to 3 per cent, of water, according 
 to the hygrometric state of the atmosphere. 
 
 It is rolled slowly at first, and afterward from 8 to 
 10 revolutions of the roller per minute, for 1 hour for 
 50 lbs., and 3 hours for 150 lbs. of composition. A 
 little water is added, as the process advances, if the 
 composition gets very dry — which is judged of by its 
 color. 
 
 When the materials are thoroughly incorporated, 
 the cake is of a uniform, lively, grayish, dark color. In 
 this state it is called mill-cake. 
 
 The quality of the powder depends much on the 
 thorough incorporation of the materials, and burns 
 more rapidly as this operation is more thoroughly per- 
 formed. 
 
 The mill-cake is next taken to the press-house, to be 
 pressed into a hard cake. 
 
 Pressing. The mill-cake is sprinkled with about 3 
 per cent, of water, and arranged in a series of layers 
 about 4 inches thick, separated by brass plates. A pow- 
 erful pressure is brought to bear on the layers, which 
 are subjected to the maximum pressure for about 10 to 
 15 minutes, when it is removed. Each layer is thus 
 formed into a hard cake about an inch thick. 
 
 Granulating. The cake is broken into pieces by means 
 of iron-toothed rollers revolving in opposite directions, 
 their axes being parallel and the distance between them 
 regulated as required. Fluted rollers are sometimes used. 
 The pieces are passed through a succession of rollers, 
 each series being closer together, by which the pieces 
 
MANUFACTURE. 25 
 
 are broken into others still smaller, which pass over a 
 sieve to another roller, the small grains passing through 
 the sieve into a receiver below, until the whole is re- 
 duced to the required size. The various-sized grains are 
 separated by the sieves between the different rollers. 
 
 Glazing. Several hundred pounds of the grained 
 powder, containing from 3 to 4 per cent, of water, 
 are placed in the glazing barrel, which is made to re- 
 volve from 9 to 10 times per minute, and in some 
 mills from 25 to 30 times per minute. Usually ffom 
 10 to 12 hours are required to give the required glazing. 
 In this operation the sharp angles are broken off, there- 
 by diminishing the dust produced in transportation, 
 and the surface of the grain receives a bright polish. 
 
 Drying. The powder is spread out on sheets stretch- 
 ed upon frames in a room raised to a temperature of 
 140° to 180° by steam-pipes or by a furnace. The tem- 
 perature should be raised gradually, and should not 
 exceed 180°, ventilation being kept up. 
 
 Dusting. The powder is finally sifted through fine 
 sieves, to remove all dust and fine grains. 
 
 15. Round powder. In case of emergency, and 
 when powder cannot be procured from the mills, it may 
 be made, in a simple and expeditious manner, as fol- 
 lows : Fix a powder-barrel on a shaft passing through 
 its two heads, the barrel having ledges on the inside; 
 to prevent leakage, cover it with a close canvas glued 
 on, and put the hoops over the canvas. Put into 
 the barrel 10 lbs. of sulphur in lumps, and 10 lbs. of 
 charcoal, with 60 lbs. of zinc balls or of small shot 
 (down to No. 4, 0.014 in. in diameter nearly); turn 
 it, by hand or otherwise, 30 revolutions in a minute. 
 
26 GUNPOWDER. MANUFACTURE. 
 
 To 10 lbs. of this mixture thus pulverized, add 30 lbs. 
 of nitre, and work it two hours with the balls ; water 
 the 40 lbs. of composition with 2 quarts of water, 
 mixing it equally with the hands, and granulate with 
 the graining-sieve. The grains thus made, not being 
 pressed, are too soft. To make them hard, put them 
 into a barrel having 5 or 6 ledges projecting about 
 0.4 in. inside ; give it at first 8 revolutions in a min- 
 ute, increasing gradually to 20. The compression will 
 be proportionate to the charge in the barrel, which 
 should not, however, be more than half full ; continue 
 this operation until the density is such that a cubic 
 foot of the powder shall weigh 855 oz., the mean den- 
 sity of round powder ; strike on the staves of the bar- 
 rel from time to time, to prevent the adhesion of the 
 powder. 
 
 Sift the grains and dry the powder as usual. That 
 which is too fine or too coarse is returned to the pulver- 
 izing-barrel. 
 
 This powder is round, and the grain is sufficiently 
 hard on the surface, but the interior is soft, which makes 
 it unfit for keeping, and may cause it to burn slowly. 
 This defect may be remedied by making the grains at 
 first very small, and by rolling them on a sheet or in a 
 barrel, watering them from time to time, and adding 
 pulverized composition in small proportions ; in this 
 way, the grains will be formed by successive layers ; 
 they are then separated according to size, glazed and 
 dried. 
 
 It appears from experiments that the simple incorpo- 
 ration of the materials makes a powder which gives 
 nearly as high ranges with cannon as grained powder. 
 
INSPECTION, PROOF, ETC. 
 
 The incorporated dust from the rolling-barrel may be 
 used in case of necessity. 
 
 INSPECTION, PROOF, ETC. 
 
 16. Proving instruments Before powder for the 
 military service is received from the manufacturer, it is 
 inspected and proved. For this purpose, at least 50 
 barrels are thoroughly mixed together. One barrel of 
 this is proved by firing three rounds from a musket, 
 with service-charge, if it be musket powder ; if cannon 
 or mammoth powder, from an 8-inch columbiad, with 
 10 lbs. and a solid shot of 65 lbs. weight and 7.88 inches 
 in diameter ; if it be mortar powder, from an 8-inch 
 mortar, with 1.25 lb. and a shell 7.88 inches in diameter, 
 weighing 47.5 lbs. The general character of the grain, 
 and its freedom from dust, are noted. 
 
 General Qualities. Gunpowder should be of an even- 
 sized grain, angular and irregular in form, without 
 sharp corners, and very hard. When new, it should 
 leave no trace of dust when poured on the back of the 
 hand, and when flashed in quantities of 10 grains on a 
 copper plate, it should leave no bead or foulness. It 
 should give the required initial velocity to the ball, and 
 not more than the maximum pressure on the gun, and 
 should absorb but little moisture from the air. 
 
 Size of grain. The size of the grain is tested by 
 standard sieves made of sheet brass pierced with round 
 holes. Two sieves are used for each kind of powder — 
 Nos. 1 and 2 for mortar, 3 and 4 for musket, 5 and 6 for 
 cannon powder. 
 
 Diameter of holes for mortar-powder : No. 1, 0.1 inch; 
 
28 GUNPOWDER. 
 
 No. 2, 0.07 inch. For musket-powder : No. 3, 0.06 inch; 
 No. 4, 0.035 inch. For cannon-powder: No. 5, 0.31 
 inch; No. 6, 0.27 inch. 
 
 Mortar-powder. All should pass through sieve No. 1 ; 
 none through No. 2. 
 
 Musket-potvder. All should pass through No. 3, and 
 none through No. 4. 
 
 Cannon-powder. All should pass through No. 5, and 
 none through No. 6. 
 
 Gravimetric density. Is the weight of a given meas- 
 ured quantity. It is usually expressed by the weight 
 of a cubic foot in ounces. 
 
 This cannot be relied upon for the true density when 
 accuracy is desired, as the shape of the grain may make 
 the denser powder seem the lighter. 
 
 Specific gravity. The specific gravity of gunpow- 
 der must be not less than 1.75 ; and it is important that 
 it should be determined with accuracy. Alcohol and 
 water saturated with saltpetre have been used for 
 this purpose ; but they do not furnish accurate results. 
 Mercury, only, is to be relied upon. 
 
 Mercury densimeter. This apparatus was invented 
 by Colonel Mallet, of the French army, and M. Bianchi, 
 and consists of an open vessel containing mercury, 
 a frame supporting a glass globe communicating by 
 a tube with the mercury in the open vessel, and joined 
 at top to a graduated glass tube, which communi- 
 cates by a flexible tube with an ordinary air-pump. 
 Stop-cocks are inserted in the tubes above and below 
 the glass globe, and a diaphragm of chamois-skin is 
 placed over the orifice at the bottom of the globe, 
 and one of wire-cloth over the upper orifice. 
 
29 
 
 The operation consists as follows: Fill the globe 
 with mercury to any mark of the graduated tube, by 
 means of the air-pump ; close the stop-cocks ; detach 
 the globe, full of mercury, and weigh it ; empty and 
 clean the globe; introduce into it a given weight of 
 gunpowder ; attach the globe to the tubes ; exhaust 
 the air till the mercury fills the globe and rises to 
 the same height as before; shut the stop-cocks; take 
 off the globe and weigh it as before. If we represent 
 by a the weight of the powder in the globe, by P 
 the weight of the globe full of mercury, by P' the 
 weight of the globe containing the powder and mer- 
 cury, and by D the specific gravity of the mercury. 
 
 The specific gravities of the powder and the mer- 
 cury being proportional to the weights of equal volumes 
 of these two substances, we have 
 
 aiP-P'+a: :d:B 
 
 hence ^=— — ■= 
 
 P— P'+a 
 
 A mean of two or three results will give the true 
 specific gravity. 
 
 The density of some samples of powder has been 
 brought up to 1.831. 
 
 Initial velocity. The initial velocity is determined 
 by means of the Ballistic Pendulum, or by Captain Ben- 
 ton's Electro-Ballistic Pendulum. For the method of 
 using this machine, see section 408. 
 
 The standard initial velocities of the different pow- 
 ders remain to be determined. 
 
 Strain upon the gun. This is determined by Cap- 
 tain Rodman's pressure-piston, which will be explained 
 hereafter. 
 
J 
 
 30 GUNPOWDEK. INSPECTION, ETC. 
 
 Mortar-powder should not give a greater pressure 
 than Jft/zn^ounds on the square inch. 
 
 Cannon-powder should not give a greater pressure 
 than ■-■:•;.."?? pounds on the square inch. 
 
 Inspection report. The report of inspection should 
 show the place and date of fabrication and of proof, the 
 hind of powder and its general qualities, as the number 
 of grains in 100 grs., whether hard or soft, round or an- 
 gular, of uniform or irregular size, and if free from dust 
 or not ; the initial velocities obtained in each fire ; the 
 amount of moisture absorbed ; and, finally, the height 
 of the barometer and hygrometer at the time of proof. 
 
 17. Packing. Government powder is packed in bar- 
 rels of 100 lbs. each. The barrels are made of well- 
 seasoned white oak ; and hooped with hickory or cedar 
 hoops, which should be deprived of their bark to ren- 
 der them less liable to be attacked by worms. Barrels 
 made of corrugated tin are undergoing trial, to test 
 their fitness to replace those made of wood. 
 
 Maries on tlie barrels. Each barrel is marked on 
 both heads (in white oil-colors, the head painted black) 
 w^ith the number of the barrel, the name of the manu- 
 facturer, year of fabrication, and the kind of powder, — 
 cannon, (used for heavy cannon,) mortar, (used for mor- 
 tars and field cannon,) or musket — the mean initial ve- 
 locity, and the pressure per square inch on the pressure- 
 piston. Each time the powder is proved, the initial ve- 
 locity is marked below the former proofs and the date 
 of the trial opposite it. 
 
 18. Analysis. Whatever may be the mode of proof 
 adopted, it is essential, in judging of the qualities of 
 gunpowder, to know the mode of fabrication and the 
 
ANALYSIS. 91 
 
 proportions and degree of purity of the materials. The 
 latter point may be ascertained by analysis. 
 
 In the first place, determine the quantity of water 
 that the powder contains, by subjecting it to a temper- 
 ature of 212°, in a stove or in a tube with a current of 
 warm air passing over it, until it no longer loses in 
 weight. The difference in weight, before and after dry- 
 ing, gives the amount of moisture contained in the 
 powder. 
 
 To determine the quantity of saltpetre. In a vessel 
 of tinned copper, like a common coffee-pot, dissolve 
 1,000 grains of powder, well dried before weighing, in 
 2,000 grains of distilled water, and heat it until it boils; 
 let it stand a moment, and then decant it on a piece of 
 filtering-paper, doubled exactly in the middle; repeat 
 this operation four times; at the fourth time, instead of 
 decanting, pour the whole contents of the vessel on the 
 filter; drain the filter^ and wash it several times with 
 2,000 grains of water heated in the vessel, using in all 
 these operations 10,000 grains of water. After passing 
 through the filters, this water contains in solution all 
 the saltpetre, the quantity of which is ascertained by 
 evaporating to dryness. Dry the double filter with the 
 mixture of coal and sulphur, and take the weight of 
 this composition by using the exterior filter to ascertain 
 the weight of that on which the composition remains; 
 this weight serves to verify that of the saltpetre and to 
 estimate the loss in the process. 
 
 To determine the quantity of charcoal directly. To 
 separate the sulphur from the charcoal, subject the 
 powder, either directly or after the saltpetre has been 
 dissolved out, to the action of a boiling solution of the 
 
 CTa R a * 
 ' or THE 
 
 UNIVERSITY 
 
32 GUNPOWDER.- 
 
 sulphide of potassium or sodium, which dissolves the 
 sulphur and leaves the charcoal, the weight of which 
 may be easily determined. 
 
 It is important that the sulphides of potassium and 
 sodium used in dissolving the sulphur, should contain 
 no free potassa or soda; for each of these alkalies would 
 dissolve a part of the carbon — particularly of the 
 brown coal. 
 
 The sulphide of carbon also dissolves the sulphur 
 contained in powder, and may be used to determine the 
 weight of charcoal which it contains. 
 
 The charcoal, separated from the saltpetre and sul- 
 phur, is dried with care and weighed, and should then 
 be submitted to analysis in an apparatus used for burn- 
 ing organic matters. The composition of the charcoal 
 may be judged of by comparing it with the results ob- 
 tained in the analysis of charcoal of known quality 
 used in the manufacture of powder. 
 
 To determine the quantity cf sulphur directly. Mix 
 and beat in a mortar 10 grains of dry powder, 10 of 
 subcarbonate of potash, 10 of saltpetre, and 40 of 
 chloride of sodium ; put this mixture in a vessel (cap- 
 sule) of platinum or glass, on live coals, and, when the 
 combination of the materials is completed and the mass 
 is white, dissolve it in distilled water, and saturate the 
 solution with nitric acid ; decompose the sulphate which 
 has been formed, by adding a solution of chloride of 
 barium, in which the exact proportions of the water 
 and the chloride are known. According to the atomic 
 proportions, the quantity of sulphur will be to that of 
 the chloride of barium used as 20.12 to 152.44. 
 
 19. Hygrometric qualities. The susceptibility of pow- 
 
EESTOEATION. 33 
 
 der to absorb moisture is due to the charcoal and the 
 presence of deliquescent salts, principally chloride of 
 sodium or common salt. The absorbent power may be 
 judged of by exposing 1 lb. to the air in a moist place 
 (such as a cellar which is not too damp) on a glazed 
 earthen dish, for 15 or 20 days, stirring it sometimes so 
 as to expose the surface better; the powder should be 
 previously well dried, at the heat of about 140°. Well- 
 glazed powder, made of pure material, treated in this 
 way, will not increase in weight more than 5 parts in 
 1,000, or a half of one per cent. 
 
 20. Quickness of burning. The relative quickness 
 of two different powders may be determined by burn- 
 ing a train laid in a circular or other groove which re- 
 turns into itself, one half of the groove being filled with 
 each kind of powder, and fire communicated at one of 
 the points of meeting of the two trains; the relative 
 quickness is readily deduced from observation of the 
 point at which the flames meet. 
 
 21. Restoring unserviceable powder. When the 
 quantity of water does not exceed 7 per cent., the pow- 
 der may be restored by drying ; this may be effected in 
 the magazine, if it be dry, by means of ventilation, or 
 by the use of the chloride of calcium for twenty or 
 thirty days. 
 
 Quick-lime may be used ; but the use of it is attend- 
 ed with danger; on account of the heat evolved in 
 slaking. 
 
 When powder has absorbed from 7 to 12 per cent, 
 of water, it may still be restored by drying in the sun 
 or drying-house; but it remains porous and friable, and 
 unfit for transportation : in this case it is better to work 
 
 3 
 
34 GUNPOWDER. PRESERVATION. 
 
 it over. In service, it may be worked by means of the 
 rolling-barrels, as described for making round powder. 
 When powder has been damaged with salt water, 
 or become mixed with dirt or gravel, or other foreign 
 substances which cannot be separated by sifting, or 
 when it has been under water, or otherwise too much 
 injured to be reworked, it must be melted down to ob- 
 tain the saltpetre by solution, nitration, and evaporation. 
 
 22. storage, &c. In the powder-magazines, the bar- 
 rels are generally placed on the sides, three tiers high, 
 or four tiers if necessary ; small skids should be placed 
 on the floor, and between the several tiers of barrels, 
 in order to steady them ; and chocks should be placed 
 at intervals on the lower skids, to prevent the rolling 
 of the barrels. The powder should be separated ac- 
 cording to its kind, the place and date of fabrication, 
 and the proof range. Fixed ammunition, especially for 
 cannon, should not be put in the same magazine with 
 powder in barrels, if it can be avoided. 
 
 Besides being recorded in the magazine book, each 
 parcel of powder should be inscribed on a ticket attach- 
 ed to the pile, showing the entries and the issue. 
 
 23. Pre§ervation. For the preservation of the pow- 
 der, and of the floors and lining of the magazine, it is 
 of the greatest importance to preserve unobstructed the 
 circulation of the air, under the flooring as well as above. 
 The magazine should be opened and aired in clear, dry 
 weather, when the air outside is colder than that in- 
 side the magazine ; the ventilators must be kept free ; 
 no shrubbery or trees should be allowed to grow so near 
 as to protect the building from the sun. The moisture 
 of a magazine may be absorbed by chloride of calcium, 
 
EFFECTS OF GUNPOWDER. 35 
 
 suspended in an open box under the arch, and renewed 
 from time to time ; quick-lime, as before observed, is 
 dangerous. 
 
 The sentinel or guard at a magazine, when it is open, 
 should have no fire-arms ; and every one who enters the 
 magazine should take off his shoes, or put socks over 
 them; no sword or cane, or any thing which might 
 occasion sparks, should be carried in. 
 
 24. Tran§p©rtation. Barrels of powder should not 
 be rolled for transportation ; they should be carried in 
 hand-barrows, or slings made of rope or leather. In 
 moving powder in the magazine, a cloth or carpet 
 should be spread ; all implements used there should 
 be of wood or copper ; and the barrels should never be 
 repaired in the magazine. 
 
 When it is necessary to roll the powder, for its bet- 
 ter preservation and to prevent its caking, this should 
 be done with a small quantity at a time, on boards in 
 the magazine yard. 
 
 In wagons, barrels of powder must be packed in 
 straw, secured in such a manner as not to rub against 
 each other, and the load covered with thick canvas. 
 
 EFFECTS OF GUNPOWDER* 
 
 25. History, etc. The projectile arms of the ancients, 
 such as bows, ballistas, and catapults, were operated 
 by the same motive power — that of the spring. 
 
 Although large masses were thrown from these 
 machines, the velocity imparted was feeble, as the 
 springs rapidly lost their power, from being bent ; and 
 
 * Vide Piobert's Cours d? Artillerie. 
 
36 GUNPOWDEK. ITS EFFECTS. 
 
 the introduction of gunpowder, a more certain as well 
 as powerful agent, gradually caused them to be super- 
 seded. 
 
 As before stated, the power of this agent is essen- 
 tially due to the almost instantaneous development of 
 expansive gases and heat by combustion ; and although 
 its properties were known for a long time, its use was 
 at first confined to fireworks and incendiary composi- 
 tions alone. 
 
 The advantage of using an agent capable of commu- 
 nicating great velocity to a projectile, arises not only 
 from the intensity of the shock, the possibility of dis- 
 abling a large number of men, and penetrating very re- 
 sisting objects, but from the fact that it allows of the 
 use of lighter machines, whereby the projectile can be 
 directed with greater ease and certainty against its 
 object. 
 
 Although the combustible nature of powder was 
 known in Asia from the earliest times, and its prop- 
 erties were described by Marcus Grsecus and Roger 
 Bacon, its application to projectiles seems to have been 
 a subsequent result of accident. 
 
 It is stated that about the year 1330, Berthold 
 Schwartz, a monk of Fribourg, was engaged in making 
 experiments with a mixture of saltpetre, sulphur, and 
 charcoal, such as described by Marcus Graecus, and had 
 left the mixture in a mortar, covered with a large stone, 
 when it unexpectedly caught fire and exploded, throw- 
 ing the stone to a distance with great force. The ex- 
 periment was repeated, and with such success that mili- 
 tary men saw at once that it could be applied to move 
 large projectiles. Its progress as a projectile power, 
 
DISCOVERY. 37 
 
 however, was comparatively slow, and it was only at 
 the beginning of the 16th century that it was generally 
 used for military purposes. 
 
 For a long time after its introduction, gunpowder 
 was used in the form of dust, or " mealed powder," 
 from which it derived its name ; but it was found dim- 
 cult to load small arms with gunpowder in this condi- 
 tion, on account of the moisture which sometimes collects 
 in the bore after a few discharges. To overcome this 
 difficulty, it was given a granular form, and received the 
 name of " musket powder." It was soon discovered, 
 however, that two parts of grained powder produced as 
 much effect as three parts of mealed powder ; but the 
 larger fire-arms of the day had not sufficient strength to 
 resist this increased force, and mealed powder continued 
 to be used until the close of the 16th century. 
 
 At first, the ingredients of powder were converted 
 into cake with a hand-pestle; a process which gave 
 grains of very irregular size and shape. It was after- 
 ward discovered that the quality could be much im- 
 proved by careful manipulation, without sensibly alter- 
 ing the proportions of the ingredients first established. 
 
 Any improvement in gunpowder which increases its 
 strength, also increases its injurious effects on the arms 
 in which it is used. It becomes necessary, therefore, to 
 study the form and thickness of fire-arms, and the na- 
 ture of the agent whose operations they are intended to 
 restrain and direct. 
 
 It is impossible to embrace in a single glance the de- 
 tails of a phenomenon as complicated as the explosion 
 of a charge of powder. The senses cannot detect the 
 relations which exist between the partial operations of 
 
38 GUNPOWDER. ITS EFFECTS. 
 
 a phenomenon, where they are produced with such ra- 
 pidity that they seem blended into one. In this case 
 the only sure method of investigation is to separately 
 study the different facts, and then unite them as a whole, 
 borrowing from the physical sciences a thorough knowl- 
 edge of the substances operated upon. 
 
 If the numerous circumstances which influence the 
 results of the explosion of gunpowder, and the enor- 
 mous expansive force which is developed in its limited 
 duration, prevent us from accurately determining the 
 measure of its effects, we can at least determine the 
 limits between which this measure is included ; which 
 is sufficient for artillery purposes. From the results 
 thus obtained were calculated the iron and bronze how- 
 itzers introduced to supersede those of Gribeauval's sys- 
 tem. With less thickness of metal, these pieces were 
 found to answer every requirement of service ; a fact 
 which tends to confirm the accuracy of the data from 
 which they were constructed. 
 
 26. Expio§i©n. The phenomenon of the explosion 
 of powder may be divided into three distinct parts, viz. : 
 ignition, inflammation, and combustion. 
 
 By ignition is understood the setting on fire of a 
 particular point of the charge; by inflammation, the 
 spread of the ignition from one grain to another ; and 
 by combustion, the burning of each grain from its sur- 
 face to centre. 
 
 27. ignition. Gunpowder may be ignited by the 
 electric spark, by contact with an ignited body, or by a 
 sudden heat of 572° Fahrenheit. A gradual heat de- 
 composes powder without explosion by subliming the 
 sulphur. Flame will not ignite gunpowder unless it 
 
COMBUSTION. 39 
 
 remains long enough in contact with the grains to heat 
 them to redness. Thus, the blaze from burning paper 
 may be touched to grains of powder without igniting 
 them, owing to the slight density of the name, and the 
 cooling effect of the grains. It may be ignited by fric- 
 tion, or a shock between two solid bodies, even when 
 these are not very hard. Experiments in France, in 
 1825, show that powder may be ignited by the shock 
 of copper against copper, copper against iron, lead 
 against lead, and even lead against wood ; in handling 
 gunpowder, therefore, violent shocks between all solid 
 bodies should be avoided. 
 
 The time necessary for the ignition of powder varies 
 according to circumstances. For instance, damp pow- 
 der requires a longer time for ignition than powder per- 
 fectly dry, owing to the loss of heat consequent on the 
 evaporation of the water ; a powder, the grain of which 
 has an angular shape and rough surface, will be more 
 easily ignited than one of rounded shape and smooth 
 surface ; a light powder, more easily than a dense one ; 
 and a powder made of a black charcoal, more easily than 
 one made of red, inasmuch as the latter is compelled 
 to give up its volatile ingredients before it is acted on 
 by the nitre. 
 
 28. Combu§tion. The velocity of combustion is the 
 space passed over by the surface of combustion in a 
 second of time, measured in a direction perpendicular 
 to this surface. 
 
 The diameter of the largest-size grain of cannon- 
 powder does not exceed 0.1 inch ; the time of its com- 
 bustion, therefore, is altogether too transient to be 
 ascertained by direct observation. It may be deter- 
 
40 GUNPOWDER. ITS EFFECTS. 
 
 mined by compressing the composition 
 into a tube and burning it, or by burn- 
 ing the " press-cake." In the latter case, 
 take a prism of the cake about fourteen 
 inches long and one inch square at the 
 base. Smear the sides with hogs' lard, 
 and place it on end in a shallow dish of 
 water. The object of the lard is to pre- 
 vent the spread of the flame to the sides ; 
 and the water is to prevent the lower end from being 
 ignited by burning drops of powder. Set the upper 
 end on fire, and note the time of burning of the column 
 with a stop-watch beating tenths of seconds. 
 
 In either way it will be shown that the composition, 
 if homogeneous, burns in parallel layers, and that the 
 velocity of combustion is uninfluenced by the size of 
 the column, or by the temperature and pressure of the 
 surrounding gas. 
 
 The velocity of combustion of dry French war- 
 powder is thus found to be 0.48 in., and of English 
 powder, which American powder closely resembles, it 
 is about 0.4 in. 
 
 It may be shown by direct experiment that the 
 burning of a grain of powder in a fire-arm, is progres- 
 sive, and that the size of the grain exerts a great influ- 
 ence on the velocity of the projectile, especially in short 
 arms. 
 
 For this purpose take a mortar eprouvette and load 
 it with a single fragment of powder weighing forty-six 
 grains ; fire it, and the ball will not be thrown out of 
 the bore ; divide the same weight into seven or eight 
 fragments, and it will barely be thrown out of the 
 
COMBUSTION. 41 
 
 bore ; divide it into fifteen fragments, and it will "be 
 thrown about ten feet; fifty fragments will throw it 
 about thirty feet ; and the same weight of cannon-pow- 
 der, about one hundred and seventy feet. 
 
 The progressive burning of powder is further con- 
 firmed by the fact, that burning grains are sometimes 
 projected from a gun with sufficient force to perforate 
 screens of paper, wood, and lead, at considerable dis- 
 tances. It is even found that they are set on fire in the 
 gun, and afterward extinguished in the air before they 
 are completely consumed. The large grains of powder 
 used in the fifteen-inch columbiad are thrown out burn- 
 ing, to a distance of one hundred yards. 
 
 The velocity of combustion of powder varies with 
 the nature, proportions, trituration, density, and condi- 
 tion of the ingredients. 
 
 Purity of ingredients. To secure the greatest ve- 
 locity of combustion, it is necessary that the nitre and 
 sulphur should be pure, or nearly so. This can always 
 be effected by a proper attention to the prescribed 
 modes of refining ; but with the charcoal it is different, 
 for the part which it plays in combustion depends upon 
 certain characters which are indicated by its color and 
 texture. The velocity of combustion will be greater 
 for red charcoals than those that are black and strongly 
 calcined ; and for light and friable charcoals, than those 
 that are hard and compact. It appears, in fact, to be 
 nearly proportioned to t.-e combustibility of the char- 
 coals given in the tables on page 19. 
 
 Proportions. The proportions of the ingredients 
 have a very great effect on the combustion ; by vary- 
 ing them, all velocities between and .55 inch can be 
 
42 
 
 GUNPOWDER. ITS EFFECTS. 
 
 obtained ; the latter number can scarcely be exceeded. 
 The proportions which give a maximum, appear to be 
 comprised between the two following: 
 
 Nitre, 76. Charcoal, 15. Sulphur, 9. 
 
 " 76. " 14. " 10. 
 
 As it is often useful in preparing fireworks to know 
 the proportions which will give a certain velocity of 
 combustion, a table is given of a series of proportions 
 of nitre, sulphur, and charcoal, and the corresponding 
 velocities of combustion : 
 
 Sixty parts of nitre, compounded with certain pro- 
 portions of sulphur and charcoal, gave the following 
 velocities: 
 
 Parts of 
 Sulphur. 
 
 
 
 
 Parts of Black Charcoal. 
 
 
 
 
 
 5 
 
 10 
 
 11 
 
 15 
 
 20 
 
 30 
 
 60 
 
 Inch. 
 
 Inch. 
 
 Inch. 
 
 Inch. 
 
 Inch. 
 
 Inch. 
 
 Inch. 
 
 Inch. 
 
 
 
 .0 
 
 .02 
 
 . 11 
 
 .14 
 
 .24 
 
 .34 
 
 .43 
 
 .07 
 
 5 
 
 .0 
 
 .05 
 
 .24 
 
 .30 
 
 .43 
 
 .47 
 
 . 35 
 
 .00 
 
 8 
 
 . 
 
 .06 
 
 .50 
 
 .51 
 
 .49 
 
 .41 
 
 .20 
 
 .00 
 
 15 
 
 .0 
 
 .08 
 
 .47 
 
 .49 
 
 .47 
 
 .39 
 
 . 16 
 
 .00 
 
 .0 
 
 . 11 
 
 .43 
 
 .44 
 
 .36 
 
 .35 
 
 . 14 
 
 .00 
 
 20 
 
 .0 
 
 .16 
 
 .39 
 
 .40 
 
 . 38 
 
 .30 
 
 . 10 
 
 .00 
 
 30 
 
 60 
 
 .0 
 
 .27 
 
 .34 
 
 .33 
 
 .29 
 
 . 21 
 
 .01 
 
 .00 
 
 .0 
 
 .00 
 
 00 
 
 .00 
 
 .00 
 
 . 00 
 
 .00 
 
 .oo ! 
 
 1 
 
 It will be seen that the proportions 6 — 1 — 1 are 
 among those that give the greatest amount of gas in a 
 given time, other circumstances being equal; for the 
 
TRITURATION. 
 
 43 
 
 reason, that the weight burned during this time is 
 greater, and because each unit of weight gives a greater 
 volume of gas. 
 
 Trituration. Trituration of the ingredients increases 
 the velocity of combustion ; and this increase is much 
 greater as the proportions approach those which give 
 the greatest velocity. For the results of experiments on 
 this point, see accompanying table : 
 
 11 
 
 Velocity of combustion. 
 
 Remarks. 
 
 Composition. 
 
 A. 
 
 B. 
 
 c. 
 
 Hours. 
 
 
 
 1 
 
 2 
 3 
 4 
 5 
 10 
 
 Inches. 
 
 .12 
 .31 
 .38 
 .40 
 
 .44 
 .46 
 
 .48 
 
 Inches. 
 
 Inches. 
 
 .13 
 
 .25 
 .29 
 .32 
 .34 
 .35 
 .37 
 
 .0189 
 .0192 
 .0200 
 .0204 
 .0212 
 .0216 
 .0236 
 
 Compositions dry. 
 
 Nitre-. Ch'coal. Sulphur. Composition. 
 
 A, 75.00 12.5 12.50 Gunpowder. 
 
 B, 68.00 12.0 28.00 Fuze composition. 
 
 C, 66.66 2.0 31.34 Port-fire " 
 
 The nitre was taken as it came from 
 the refinery. The sulphur and charcoal 
 had already been triturated in the roll- 
 ing-barrels. 
 
 Density. For each set of proportions, the maximum 
 velocity corresponds to a very small density. By in- 
 creasing the density, the velocity is diminished; and 
 more rapidly for quick compositions than slow ones. 
 When in the form of a dust, gunpowder composition 
 burns more slowly without compression than with it. 
 For the results of experiments on the preceding compo- 
 sitions, see the following table ; the trituration was ex- 
 tended to ten hours : 
 
44 
 
 GUNPOWDER. ITS EFFECTS. 
 
 Density. 
 
 Velocity of combustion. 
 
 Remarks. 
 
 Composition. 
 
 A. 
 
 B. 
 
 C. 
 
 0.80 
 
 .360 
 
 .310 
 
 
 The pulverized composition is simply 
 poured into a tube, and settled by 
 striking lightly on a table. 
 
 1.00 
 
 .440 
 
 .410 
 
 .0319 
 
 The composition poured in as above, 
 and compressed under a weight of 
 22 lbs. without shock. 
 
 1.20 
 
 .470 
 
 .390 
 
 .0295 
 
 Composition driven with a mallet 
 weighing 2.2 lbs., falling through a 
 height of 3.9 inches. 
 
 1.40 
 
 .480 
 
 .380 
 
 .0252 
 
 Same, save the height, which was 27 
 
 inches. 
 These densities were obtained by in- 
 
 1.60 
 
 .890 
 
 .366 
 
 .0224 
 
 
 
 
 
 creasing the number of blows with 
 
 1.80 
 
 .443 
 
 .360 
 
 .0220 
 
 the mallet for each ladleful of compo- 
 sition. 
 
 2.00 
 
 
 .340 
 
 
 The density of a composition under the 
 
 2.16 
 
 
 .330 
 
 
 same pressure, increases with the 
 trituration of the ingredients. 
 
 Moisture. By moistening the composition with pure 
 water, alcohol, or vinegar, and then drying it com- 
 pletely, the velocity of combustion is increased. With 
 pure water alone, this increase of velocity may amount 
 to 0.1 of an inch. On the contrary, the velocity is 
 diminished where oils, fatty or resinous substances, are 
 added to the composition, or when it incloses water or 
 
 other liquids. 
 
 OW' 
 
 '-v &4 * 
 
 d>.^ 
 
 Dry Powder, or one containing \ per cent, of moisture, has a velocity of 0.48 in. 
 
 „ 
 
 0.39 in. 
 0.33 in. 
 
 29. Law of formation of gaseous product*. When 
 the form and size of the grains and the velocity of com- 
 bustion are known, we can ascertain, at any given mo- 
 
FOKMATION OF GASEOUS PRODUCTS. 
 
 45 
 
 Fig. 2. 
 
 ment, the amount of powder consumed, as the velocity 
 is uniform and independent of the surface. 
 
 Spherical grain. Take a spherical grain of powder 
 of homogeneous structure, one that will completely burn 
 up in -Jq- of a second. Apply fire at any point 
 of its surface, the flame will immediately 
 envelop it, and burn away the first spheri- 
 cal layer ; if, for example, we suppose the 
 time of this partial combustion be T V of 
 the time required to burn up the entire grain, then the 
 radius of the remaining sphere will be only T 9 ^- of the 
 first ; but the volumes of spheres being to each other 
 as the cubes of their radii, the primitive sphere will be 
 to the one which remains after the burning of the first 
 layer, as 1.0 is to 0.729, the cube of .9. Subtracting the 
 second of these numbers from the first, we shall have 
 0.271, which expresses the difference of volumes of the 
 two spheres, or the amount consumed in the first T V of 
 time, compared to that of the entire grain. By making 
 similar calculations on the other layers, we shall obtain 
 the results contained in the following table : 
 
 Time of burning 
 
 0.000 
 
 .100 
 
 .200 
 
 .300 
 
 .400 
 
 .500 
 
 .600 
 
 .700 
 
 .800 
 
 .900 
 
 1.000 
 
 Decreasing radii 
 
 1.000 
 
 .900 
 
 .800 
 
 .700 
 
 .600 
 
 .500 
 
 .400 
 
 .300 
 
 .200 
 
 .100 
 
 0.000 
 
 Volumes of grain 
 
 1.000 
 
 .729 
 
 •m 
 
 .343 
 
 .216 
 
 .125 
 
 .064 
 
 .027 
 
 .008 
 
 .001 
 
 0.000 
 
 Volumes burnt 
 
 0.000 
 
 .271 
 
 .488 
 
 .657 
 
 .784 
 
 .875 
 
 .936 
 
 .973 
 
 .992 
 
 .999 
 
 1.000 
 
 Volumes burnt in each 0".10 
 
 0.000 
 
 .271 
 
 .217 
 
 .171 
 
 .127 
 
 .091 
 
 .061 
 
 .037 
 
 .019 
 
 .007 
 
 0.001 
 
 It will be seen from this, that for equal intervals of 
 time, those taken in the first period of combustion give 
 forth very much larger amounts of gas than those taken 
 in the last. If, instead of a sphere, we suppose the 
 
46 GUNPOWDER. ITS EFFECTS. 
 
 grain to be & polyhedron circumscribing a 
 
 sphere, the burning layers being parallel, 
 
 the decreasing grain will continue to be 
 
 a similar polyhedron, circumscribing a 
 
 sphere. The results given in the table 
 
 will be strictly true for this case, as well as for grains 
 
 of conical or cylindrical form, provided their bases be 
 
 equal to their heights. 
 
 General formula. A general formula may be de- 
 duced to show the amount of gas developed at any 
 instant of the combustion of a grain or charge of pow- 
 der. For this purpose take a spherical grain of powder, 
 and consider it inflamed over its entire surface. 
 
 Let t represent the time of burning, from the in- 
 stant of ignition to the moment under consideration: t', 
 the time necessary to burn from the surface to the cen- 
 tre, or total combustion: i?, the radius of the grain. 
 
 Since the combustion passes over the radius JR in 
 
 the time t', the velocity of combustion is equal -7", and 
 
 for the time t 7 it will pass over the space t— - or H— ; 
 
 t t 
 
 the radius of the decreasing sphere will therefore be 
 jg/l— — ) The volume of the grain of powder 
 
 and that of the decreasing sphere are -^nfi 8 and 
 
 o 
 
 A. / t \ 3 
 
 7r- n IPll— — )> respectively; and their difference, or 
 the quantity of powder burned, will be equal to 
 
 3 
 
GENERAL FORMULA. 47 
 
 The first factor of this expression represents the 
 primitive volume of a grain of powder, and the other 
 expresses the relation of the volume burned to the 
 primitive volume. 
 
 The same expression will answer for all the grains 
 of a charge of powder, if they are of the same size and 
 composition ; consequently, if we let A represent the 
 volume or weight of the grains composing a charge of 
 powder, the quantity remaining unburned after the time 
 
 t will be represented by Ay 1 - t ); and the quantity 
 
 burned, by A (\-(l -J J). 
 
 Although the grains of powder are not spherical, 
 their sharp angles are partially worn away by rubbing 
 against each other in glazing and in transportation; and 
 the mode of fabrication and inspection reduces the 
 variation in size within narrow limits; therefore, if 
 we examine the influence which the actual form and 
 size of the grains exercises over the phenomenon of 
 combustion of powder, we shall find that the effect 
 varies but slightly from that due to the spherical form. 
 
 Application to ordinary powder. Take a grain of ob- 
 long form, like that of a spheroid, or cylinder termi- 
 nated by two hemispheres: it will present a greater 
 surface than a spherical grain of the same weight, and 
 consequently the amount of gas formed from it in the 
 first instants of time, will be greater, and the duration 
 of the combustion will lie less. It can be shown, how- 
 ever, that so long as the size of the grains is kept with- 
 in the regulation limits, this influence will be slight. 
 To do this, take an oblong grain the cylindrical part of 
 
48 
 
 GUNPOWDEK. ITS EFFECTS. 
 
 which has a diameter of .054 in., let it be terminated 
 by two hemispheres, and have a total length of .097 
 in. (these being the minimum and maximum size of 
 a grain of French cannon-powder, respectively) ; its 
 weight will be about .07 grain, or yy? of a gramme, 
 and with a velocity of combustion of 0.48 it will take 
 0.056" to burn up completely. 
 
 French war-powder is composed of grains of different 
 weights, numbering about 310 to every gramme, or 15.4 
 grs. Troy. If, therefore, powder contain oblong grains 
 of the size stated above, there must be others still 
 smaller : if we suppose them to be in equal quantities, 
 and the larger to be ¥ fy of the unit of weight, then the 
 smaller must be equal to T | ¥ of the unit of weight ; 
 which would be equal to spheres with a radius of 0.027 
 inch. Comparing the quantities of gas developed in 
 intervals of .008", or about | of the time necessary for 
 the combustion of the smallest grains, we obtain the 
 result in the following table : — 
 
 
 Relation of the volume of powder burned, to the vol- 
 
 Kinds of grains of Powder. 
 
 ume of the grains after a time of 
 
 0".008 
 
 0".016 
 
 0".024 
 
 0".032 
 
 0".040 
 
 0".048 
 
 0".056 
 
 Elongated grains, diamr. .054 in. ; 
 
 
 
 
 
 
 
 
 length, 0.98 in.,— 210 to the 
 
 
 
 
 
 
 
 
 gramme, or 15.4 grs., 
 
 0.310 
 
 0.555 
 
 0.737 
 
 0.864 
 
 0.946 
 
 0.987 
 
 1.000 
 
 Spherical grains ol 410 to the 
 
 
 
 
 
 
 
 
 gramme, or .056 in. diameter, 
 
 0.357 
 
 0.616 
 
 0.794 
 
 0.907 
 
 0.968 
 
 0.994 
 
 0.999 
 
 Elongated and spherical grains as 
 
 
 
 
 
 
 
 
 above, in equal quantities, form- 
 
 
 
 
 
 
 
 
 ing a mixture of 310 to the 
 
 
 
 
 
 
 
 
 gramme, 
 
 0.333 
 
 0.585 
 
 0.766 
 
 0.885 
 
 0.958 
 
 0.990 
 
 0.999 
 
 Spherical grains of 310 to the 
 
 
 
 
 
 
 
 
 gramme, or 0.063 in. diameter, 
 
 0.330 
 
 0.580 
 
 0.758 
 
 0.875 
 
 0.948 
 
 0.985 
 
 0.998 
 
 Difference between mixed grains 
 
 
 
 
 
 
 
 
 and spherical grains of the same 
 
 
 
 
 
 
 
 
 mean weight, 
 
 0.003 
 
 0.005 
 
 0.008 
 
 0.010 
 
 0.010 
 
 0.005 
 
 0.001 
 
 The differences in the results do not much exceed T ± T , 
 
INFLAMMATION. 49 
 
 and may be neglected in practice ; we may accordingly 
 consider all the grains of a charge of powder as spheres 
 with radii corresponding to their mean weight. This 
 mean weight is an important element, and may be de- 
 termined by counting the number of grains in a given 
 charge, and dividing the weight of the charge by this 
 number. 
 
 In war-powder the largest portion of each grain is 
 burned in the first two-tenths of the time required to 
 consume the entire grain : as it has been shown that a 
 grain of ordinary cannon-powder requires 0.1 second 
 for its combustion, the largest portion of the grain will 
 be burned in the first T | -^ of a second. If we consider 
 the velocity of the projectile on leaving a gun, and the 
 time necessary to overcome its inertia in the first period 
 of its movement, we shall see that a very large portion 
 of each grain is burned up before the projectile leaves 
 the gun. If the size of the grain be increased, the 
 effect will be to diminish the amount of gas evolved in 
 the first instants of time, and to diminish the pressure 
 on the breech* This principle has been made use of 
 lately to increase the endurance of large cannon. 
 
 29. inflammation. When grains of powder are uni- 
 ted to form a charge,, and fire is communicated to one 
 of them, the heated and expansive gases evolved, insin- 
 uate themselves into the interstices of the charge, en- 
 velop the grains and ignite them, one after the other. 
 
 * This idea has been carried out more fully in the experiments of Captain Rodman, 
 by converting the powder into one or more cakes, which are perforated with numer- 
 ous small holes for the passage of the flame. In this way a large portion of the 
 powder is consumed on an increasing instead of a decreasing surface, and the 
 amount of gas given out in the last moments will be greater than in the first ; and 
 thus the strain on the breech of a gun may be very much diminished without pro- 
 portionately diminishing the velocity communicated to the projectile. For actual 
 results obtained with this kind of powder, see Note appended to section 109. 
 4 
 
50 GUNPOWDER. ITS EFFECTS. 
 
 This propagation of ignition is called inflammation, 
 and its velocity the velocity of inflammation. It is 
 much greater than that of combustion, and it should not 
 be confounded with it. 
 
 The velocity with which inflamed gases move in a 
 resisting tube, like a cannon, is very great. Hutton cal- 
 culated it to be from 3,000 to 5,000 feet per second ; and 
 Robins determined it by experiment to be about 7,000 
 feet per second. 
 
 But when these gases are forced to pass through the 
 interstices of powder, the resistance offered will consider- 
 ably diminish the velocity of their expansion : it is found 
 to vary with the form and size of the grains ; and may 
 be supposed to be reduced to 33 feet per second. The 
 velocity of combustion, as before stated, is only .48 inch 
 per second. 
 
 Although the velocity of inflammation of a train of 
 powder can afford but an imperfect idea of this velocity 
 in a gun, it may be interesting to study it. 
 
 The velocity of inflammation of a train of powder 
 generally varies with the size of the grains, with the 
 quantity of powder employed, and the disposition of the 
 surrounding bodies, as will be shown by the following 
 results of actual experiment. 
 
 The amount of powder in each train was about 
 .11 lb. to the linear foot, and the time corresponding to 
 the distances was one second. 
 
 On a plane surface in the open air, . 7.87 feet. 
 
 In an uncovered trough, . . . 8.13 " 
 
 In a linen tube, .... 11.38 « 
 
 In the same tube placed in the trough, 17.48 " 
 
 In the trough covered up, . 27.88 " 
 
INFLAMMATION. 51 
 
 These velocities are less than those obtained in fire- 
 arms, for the reason that the powder is not only confined 
 at the sides, but at one end, which was not the case in 
 the experiment with the covered trough, where it could 
 expand in both directions. 
 
 A velocity of more than three hundred feet can be 
 obtained by burning quick-match inclosed in a cloth 
 tube. 
 
 The size of the cross-section influences the velocity, 
 as was shown by burning a train containing .062 lb. per 
 foot in an open trough : the velocity was 5.77 feet, in- 
 stead of 7.87 feet; and in a covered trough it was 
 twenty feet, instead of 27.88. The velocity, therefore, 
 increases with the cross-section of the train. 
 
 To determine the influence of the size of the grains 
 on the velocity of inflammation, two trains were fired, 
 one, composed of fine grains, and the other of large 
 ones ; the velocity of the first was 8.2 feet, and the 
 second was 7.54. This difference was due to the greater 
 amount of gas developed by the small grains in the first 
 instants of combustion. 
 
 The nature of the charcoal exerts an influence, the 
 black being more favorable to inflammation than the 
 red. 
 
 For a specific gravity of 1.3, the velocity is 7.5 feet. 
 
 « u "16 u "79 u 
 
 Light powder is therefore found to be more, inflam- 
 mable than heavy. 
 
 If the grains be round the interstices are larger, and 
 more favorable to the passage of the flame, and the in- 
 
52 GUNPOWDER. PEODTTCTS OF COMBUSTION. 
 
 flanimation of the mass. If they be sharp and angu- 
 lar, they will close npon each other in such a way as to 
 reduce the interstices; and although the ignition of 
 such grains may be more rapid, its propagation will be 
 diminished. 
 
 It has been shown that, when powder is burned in 
 an open train, fine powder inflames more rapidly than 
 coarse ; such, however, is not the case in fire-arms, owing 
 to the diminution of the interstices. If a charge were 
 composed of mealed powder, the flame could no longer 
 find its way through interstices, and the velocity of in- 
 flammation and combustion would become the same. 
 The velocity of inflammation of powder compressed by 
 pounding is about .64 inch, while that of mealed pow- 
 der in the same condition is only .45 in. 
 
 PRODUCTS, ETC., OF COMBUSTION. 
 
 30. Nature of products Temperature and atmos- 
 pheric pressure considerably influence the products ob- 
 tained from burning gunpowder. When exposed in the 
 open air to a temperature gradually increasing to 572° 
 Fahrenheit, the sulphur sublimes, taking with it a por- 
 
 Note. — By compressing grain-powder under a hydrostatic press it may be con- 
 verted into a solid cake, and be used in loading fire-arms, in place of the ordinary 
 cartridge. No cement is required to unite the grains, as the pressure brings the 
 particles of the surface of the grains within the limits of cohesive attraction, in 
 the same way that artificial limestone is formed by compressing sand. As the 
 pressure diminishes the interstices of the grains, it also diminishes the velocity of 
 inflammation, aad the rapidity with which the charge is converted into flame. 
 
 Experiments made at "West Point, on some specimens of powder thus prepared 
 by Dr. Doremus, of New York, showed that the pressure on the surface of the 
 bore may be increased or diminished by diminishing or increasing the pressure on 
 the cakes. 
 
 The cakes were covered by a water-proof, but highly inflammable varnish, 
 which protected the powder from moisture, without apparently diminishing its 
 inflammability. 
 
NATURE OF PEODUCTS. 53 
 
 tion of the carbpn. This was shown by Saluces, who 
 passed the volatilized products through a screen of very 
 fine cloth, and found carbon deposited on it. Powder 
 may be, therefore, completely decomposed by a gradual 
 heat, without explosion; but when suddenly brought 
 in contact with an ignited body, the temperature of 
 which is at least 572° Fahrenheit, the sulphur has not 
 time to sublime before explosion takes place 
 
 The proportions for war-powder for the United 
 States service are seventy-six parts of nitre, ten of 
 sulphur, and fourteen of carbon. By the atomic theory 
 the proportions should be 74.64 nitre, 11.85 sulphur, 
 13.51 carbon. If we adopt these last proportions, the 
 formula for gunpowder becomes 
 
 (jvo 5 +xo)+s+sa 
 
 If we suppose the ingredients to be pure, and to arrange 
 themselves under the influence of heat according to 
 their strongest affinities, there will result one equivalent 
 of nitrogen, three of carbonic acid, and one of sulphide 
 of potassium, for 
 
 (JY0 5 +1T0)+S+ZC=JV+3C0 2 +SK 
 The products are, therefore, solid and gaseous. Usually, 
 powder contains a slight quantity of moisture ; the in- 
 gredients are not absolutely pure, nor are they propor- 
 tioned strictly according to their combining equivalents ; 
 it might be expected, therefore, that the actual would 
 differ from the theoretical results. 
 
 The actual gaseous products obtained by combustion 
 are, principally nitrogen and carbonic acid, sometimes 
 carbonic oxide, a little sulphuretted hydrogen, carburetted 
 hydrogen, and nitrous oxide. The solid products are, 
 sulphide of potassium, sulphate of potassa, sub-carbonate 
 
54 GUNPOWDER. PRODUCTS OF COMBUSTION. 
 
 of potassa (mingled with a little carbon), and traces of 
 sulphur. 
 
 When the sulphide of potassium comes in contact 
 with the air, it is converted into sulphate of potassa, 
 and gives rise to the white smoke which follows the ex- 
 plosion of gunpowder. A portion of the sulphide is 
 sometimes condensed on the surface of the projectile, 
 which accounts for the red appearance of shells, some- 
 times observed in mortar-firing. 
 
 The solid products are probably volatilized at the 
 moment of explosion by the high temperature which 
 accompanies the combustion ; but, coming in contact 
 with bodies of much lower temperature, they are imme- 
 diately condensed. In chambered arms, small drops of 
 sulphur may be observed condensed on the sides of the 
 bore, which show that the sulphur has been volatilized ; 
 and we know that good powder burns on paper and 
 leaves no trace. This fact, however, was most com- 
 pletely shown by the experiments of Count Rumford. 
 This celebrated observer used a small eprouvette of 
 great strength, which he partially filled with powder, 
 and hermetically closed with a heavy weight. The 
 powder was fired by heating a portion of the eprouvette 
 to redness. Whenever the force was sufficient to raise 
 the weight, the entire products escaped; when it was 
 not, a solid substance was found condensed on the sur- 
 face of the bore furthest from the source of heat. 
 
 31. Temperature. The temperature of the gaseous 
 products of fired gunpowder has been variously estima- 
 ted. Saluces determined by experiment that pure cop- 
 per, which melts at a temperature of 4,622 Fahr., was 
 not always melted by them ; while brass, the melting- 
 
DETERMINATION OF FORCE. 
 
 55 
 
 point of which is about 3,900 Fahr., was invariably 
 melted ; he was, therefore, induced to place their tem- 
 perature at about 4,300 Fahr. As metals absorb a large 
 amount of heat before melting, it is probable that the 
 temperature of fired gunpowder is actually more than 
 is here stated. 
 
 DETERMINATION OF THE FORCE OF 
 GUNPOWDER. 
 
 32. Absolute force. The absolute force of gunpow- 
 der is measured by the pressure which it exerts when 
 it exactly fills the space in which it is fired. Various 
 experiments have been made to determine mechanically 
 the absolute expansive force of fired gunpowder, but 
 with widely different results. Robins estimated it at 
 1,000 atmospheres, Hutton at 1,800, D'Antoni from 1,400 
 to 1,900, and Rumford carried it as high as 100,000 
 atmospheres.* These discrepancies arise, in a great 
 measure, from the very great difference which exists be- 
 tween the expansive force of 
 the gases in the different mo- 
 ments of combustion, and from 
 a want of coincidence in the 
 observations. 
 
 The apparatus used by 
 Rumford to determine this 
 point consisted, essentially, of 
 a small eprouvette, E, capa- 
 ble of holding exactly 25 
 grains of powder. The orifice 
 
 * RodmaiVs experiments show the absolute pressure to be at least 13,333 atmos- 
 pheres, or 200,000 lbs. to the square inch. 
 
56 GUNPOWDER. FORCE. 
 
 was closed with a heavy weight, and the powder was 
 fired by heating the stem of the eprouvette, S, with a 
 redhot cannon-ball, B. For the first trial, he filled the 
 eprouvette with 25 grains of the best quality of dry pow- 
 der, and rested upon the cover the knob, C, of a 24-pd. 
 gun, whose weight was 8,081 lbs. Notwithstanding its 
 great strength, the eprouvette was burst at the first fire 
 into two pieces ; and the 24-pdr. was raised. Rumford 
 endeavored to show from the weight thus raised, that the 
 pressure of the gases on the sides of the eprouvette was 
 greater than 10,000 atmospheres. He further attempted 
 to show, that as the tenacity of good iron is equal to 
 4,231 times the pressure of the atmosphere on the same 
 surface, and as the surface of rupture was 13 times that 
 of the bore, the force necessary to produce the rupture 
 of the eprouvette must have been 13x4,231, or 55,003 
 atmospheres. 
 
 There are circumstances attending this experiment 
 which should be taken into account, and which will 
 very materially diminish this result. They are, the 
 diminution of the tenacity of the iron, due to heating 
 the eprouvette to produce explosion, and the incorrect 
 method by which Rumford estimated the strength of a 
 hollow cylinder subjected to a strain of expansion. 
 
 33. Relation between density and force. Experi- 
 ments were continued, with a similar apparatus, to de- 
 termine the relation between the density and the expan- 
 sive force of fired gunpowder. The capacity of the 
 eprouvette was nearly 25 grains. It was fired with vari- 
 ous charges from 1 up to 18 grains; and the expansive 
 force of each discharge was determined by the smallest 
 weight necessary to close the orifice against the escape 
 
DENSITY AND FORCE. 57 
 
 of the gas. With, the results of 85 trials a table was 
 formed, from which a curve was constructed which ex- 
 presses the relation between the density and expansive 
 force of fired gunpowder, from 1 to 15 grains. By 
 analogy and calculation, this curve was continued up to 
 a charge of 24 grains ; and for the density correspond- 
 ing to this charge, the pressure was found to be 29,1 7 8 
 atmospheres. 
 
 This pressure is much greater than that developed 
 in the explosion of projectiles and mines, owing to the 
 low temperature of the surrounding surfaces, and the 
 large amount of heat which they absorb. It is the same 
 with cannon, for the most rapid firing does not raise the 
 temperature of the bore above 210 Fahr., which is much 
 below that of the eprouvette. Besides, the powder does 
 not completely fill the space in rear of the ball ; and, 
 as powder burns progressively, this space is enlarged 
 before the gases are completely developed, and conse- 
 quently their density is diminished. There is also a loss 
 of force by the escape of the gases through the windage 
 and vent. 
 
 The following equation expresses the relation found 
 to exist between the density and expansive force of 
 charges of gunpowder, from 1 to 15 grains, fired in an 
 eprouvette the capacity of which was 25 grains, or in 
 other words, for charges in which the densities vary 
 from .04 to .6 : 
 
 p= 1.841 (905dy +0M2d ; 
 
 in which p represents the pressure in atmospheres, and 
 d the density of the inflamed products. 
 
 It will be seen from this equation, that the pressure 
 
58 
 
 GUNPOWDER. FORCE. 
 
 +tA 
 
 increases more rapidly than the density, since the expo- 
 nent of the density is greater than unity. 
 
 The density of the gases is equal to the weight of the 
 powder burned divided by the space occupied by the gases. 
 By substituting this in the equation, we can determine 
 the pressure exerted at any given instant of the com- 
 bustion. 
 
 Although this relation is deduced for a particular 
 kind of powder, it may be used for all service- powders 
 and service-charges without serious error, since the actual 
 amount of gaseous products is nearly the same for all, 
 and the densities of the highest service-charges never 
 exceed 0.6* Z^<t-rf4* 
 
 34. Force of powder when inflammation is instanta- 
 neous. If the size, form, and density of the grains of a 
 charge of powder, the velocity of combustion, and the 
 
 * The accuracy of Rumford's formula has been lately verified by a series of 
 experiments made by Captain Rodman. The apparatus used by this officer con- 
 sisted of a very thick cast-iron shell, to which was attached an indenting piston for 
 determining the pressure on the inner surface, or powder cavity of the shell. 
 
 The following table shows the pressures calculated by the formula and the pres- 
 sures obtained by the experiments, for three different densities : 
 
 Density 1 Pressure by 
 tensity. Rumford's Formula. 
 
 Pressure by 
 Rodman's Experiments. 
 
 
 1,290 lbs. 
 2,900 " 
 3, 100 " 
 
 1,066 lbs. 
 2,525 " 
 3,220 " 
 
 The lesser pressure obtained by Rodman's experiments may be in a great measure 
 explained by the facts, that the shell was not heated, but fired with a friction tube, 
 and that the gas was allowed to escape through the vent. Further experiments 
 were made which show that so long as the volume of the charge bears the same 
 proportion to the space in which it is fired, the pressure on the unit of surface 
 remains the same, no matter what may bo the amount of the charge. This follows 
 also from Rumford's formula, since the value of p is not affected so long as d remains 
 the same. 
 
FOKCE. 59 
 
 space in which it is contained, are known, we can deter- 
 mine the density of the gaseous products at any partic- 
 ular moment of combustion. For this purpose, take the 
 case in which the inflammation of the whole charge is 
 considered instantaneous, and let 
 
 P be the weight of the charge, 
 
 d' the density of the composition of which the 
 
 powder is made, 
 J^the space in which the gases expand, 
 t! the time of combustion of a single grain, 
 t the time since the combustion began, 
 d the density of the gases at a given instant. 
 
 According to section 29, the weight of powder 
 
 remaining after a time, t, will be equal to P( 1 ) , 
 
 P / A 3 
 and the volume will be equal to -^(1— — J; the 
 
 weight of gaseous products evolved will be equal to 
 
 P( 1 — ( 1 ) ) ; and their density will be equal to 
 
 this quantity divided by the space V, diminished by 
 the space occupied by the powder unburnt at the end 
 of the time t. 
 
 Or, 
 
 P 
 V 
 
 fc- j 
 
 (-H)) 
 
 Let K represent the ratio of the weight of powder 
 which would fill the space V, to the weight of the 
 charge P, and D the gravimetric density, or weight 
 
60 GUNPOWDER. — FORCE. 
 
 of a unit of volume of powder, we shall have the equa- 
 tion, 
 
 and the formula for the density of the gaseous products 
 becomes, 
 
 If the charge fill the entire space V, K—\ and 
 
 -hi? 
 
 When the grains are consumed, £=£', and^=— ; and 
 
 Having determined the mean density of the gaseous 
 products at any instant of the combustion, we can de- 
 termine the pressure exerted on the enclosing surfaces 
 by means of Eumford's formula 
 
 P= 1.841 (905dy* 0M2d . 
 
 This value of P supposes that the entire charge is 
 inflamed at the same time — a supposition that is not 
 strictly correct, except for small and lightly-rammed 
 charges. When the charge is large, and well-rammed, 
 as in cannon, it is necessary to take into consideration 
 the time of inflammation. 
 
 35. Density when the inflammation is not instan- 
 taneous. In a majority of cases the preceding formulas 
 will give the relation between the density and expan- 
 
FORCE. 
 
 61 
 
 sive force of gunpowder, without sensible error; but 
 when the grains are small, and the charge is com- 
 pressed by ramming, the interstices are diminished in 
 size, and the inflammation is comparatively less rapid ; 
 besides, the size and form of the charge exert an in- 
 fluence which increases with its length. It is proposed, 
 therefore, to modify the formulas, and adapt them to 
 the most general case, by considering the inflammation 
 progressive. 
 
 Take a charge of powder, of any form whatever, and 
 consider it ignited at the point A, the 
 inflammation will reach the surface of 
 the concentric zone J3, the radius of 
 which is tv, in the time t, v being the 
 velocity of inflammation. There will be 
 portions of the charge situated within 
 this zone which the flame will not have 
 reached ; others in which the combustion 
 is completed ; and others, between these 
 two, in which the inflammation is completed, but the 
 combustion is only partially completed. See figure 7. 
 
 y v 
 
 wrm 
 
 Fig. 1. 
 
 The extent of the inflamed zones being determined 
 by the form and dimensions of the charge, exerts a great 
 influence on the development of the gases, and conse- 
 quently on their density. 
 
 If the velocities of inflammation and combustion be 
 known, the quantity of gas formed from each zone can 
 be calculated, and the question becomes one of analysis. 
 
62 GUNPOWDER. FORCE. 
 
 In this calculation, the integral limits which refer to the 
 extent of the zones are determined by the surface of the 
 charge ; and those which refer to the progress of the 
 combustion of the grains will be the point of ignition 
 and the surface of inflammation; or, if e be the time ne- 
 cessary for the flame to reach the surface of the zone, the 
 radius of which is x, the time of partial combustion of a 
 grain of this zone will be t—e, and its complete combus- 
 tion is expressed by the relation t—t'-\-Q. 
 
 For this zone the density of the gaseous products at 
 the instant of inflammation will be <fcO, and when com- 
 pletely consumed d=D. 
 
 The intermediate values may be determined by for- 
 mula (1) 
 
 7 
 d=- 
 
 
 K- <W>i 
 
 by substituting t—e for t, and supposing JT=1, should 
 the charge completely fill the space in which it is burn- 
 ed. Integrating between the determined limits, we ob- 
 tain the mean density of the gases developed. 
 
 The solution of this question, in a general sense, is 
 very difficult, and requires the aid of the differential 
 calculus. There are particular cases, however, where 
 the solution is not difficult ; for instance, where the 
 charge is of cylindrical form and is placed at the bottom 
 of the bore of a gun. 
 
 36. Calculation of the den§ity of a charge of cylin- 
 drical form. Although the charge of a gun is ignited 
 at the rear and upper portion, we may consider that all 
 portions of the circular layer at the bottom are inflamed 
 
FORCE. 63 
 
 at once, and that the inflammation spreads by parallel 
 layers throughout its extent. The space at the bottom 
 of the bore, and the escape of gas through the vent, 
 favor this supposition. 
 
 Let L represent the total length of the charge, and 
 Q' the time necessary for the inflammation to pass over 
 this length. Let us assume that e'—nt\ t' being the 
 time necessary for the combustion of a single grain of 
 the charge ; n, therefore, is the ratio of these times. 
 
 L L 
 
 The velocity of inflammation will be -7, or — ,; and 
 
 — will represent the portion of the charge inflamed in 
 nt' 
 
 the time t The length of the charge which will be 
 
 consumed (and no portion can be entirely consumed 
 
 unless t>f) will be (t—f) — } ] and the thickness of the 
 burning layer will be the difference between these two 
 
 quantities, or — ; which is constant. 
 n 
 
 If the area of a section of the charge, perpendicular 
 to its axis, be taken as the unit of surface, the volumes 
 may be represented by their lengths. Divide the 
 length of the burning portion into a number, A, of 
 smaller sections, the length of one of the smaller sec- 
 tions will be equal to — ; if A be very large, the grains 
 
 of each very small section may be considered in the 
 same stage of combustion, and the radii of the consumed 
 layers in each grain of the small sections will be 
 represented in parts of the primitive radius, as fol- 
 lows : — 
 
64 GUNPOWDEK. FOKCE. 
 
 For the 1st, 2d, 3d. . . A— 2, A— 1, A, sections. 
 A A-l A-2 _3 _2_ 1_ 
 
 A' h ' A ' " ' V A' A' 
 
 The radii of the burning grains will be, 
 
 1 2 A-3 h— 3 A-l. 
 
 "' A A' " ' "TT 1 A ' A ' 
 and the corresponding volumes of the unburnt portions 
 will be represented by. 
 
 /1V /A 8 /A-3V /A-2V /A-1V 
 
 The volumes burned will be represented by, 
 
 If D represent the gravimetric density of the pow- 
 der, the weight of each small section will be — -D, and 
 
 the weight of the gaseous products in all the sections 
 will be 
 
 LjyU l»+2 8 +3 8 +4 8 ...+(A-l) 3 ) . 
 nfi°Y~- ¥ }' 
 
 but we know in general terms that 
 
 l3 +2 3 +3 8 ...^, or2z 8 =^±iY; 
 
 therefore the sum of the weights of the gases formed 
 will be, 
 
 If we suppose h, the number of sections, to be infi- 
 nite, the above expression will reduce to 
 LD . . LD 
 
 •(i-0= 
 
 3. 
 
 •' T n 
 
FORCE. 65 
 
 The portion of the charge entirely consumed being 
 
 ^ £ t ft 
 
 equal to —jrL, its weight will be — y-ZD, and the 
 
 total weight of gaseous matter developed will be, 
 
 nt ' n nt \ 4 / 
 
 The space which they occupy is equal to the volume 
 of the inflamed portion of the charge, diminished by 
 the volume of the unburned grains at the end of the 
 
 time t ; the volume of the burning powder is — , and 
 
 n 
 
 its weight is —D. The weight of the portion burned 
 
 being equal to f- ; that which remains unburned 
 
 n 
 
 will be equal to J- , and the density of the grains 
 
 being d\ their volume will be equal to \ — - The 
 
 nd 
 
 volume into which the gases expand will consequently 
 
 be equal to 
 
 tZ«LD 
 
 nt' 4 nd' ' 
 Finally, the mean density of the gases at the instant 
 t will be, 
 
 
 tL_ i ZIJ tTB_ 
 
 nt' T nd' 4d 
 
 From this it will be seen that the density is indepen- 
 dent of the velocity of inflammation and length of the 
 charge. The formula, however, can only be applied 
 
66 GUNPOWDEE. FOECE. 
 
 from the instant t=t' to that in which t=d' — t\ that is 
 to say, so long as there exists a portion of the charge in 
 which the combustion is ceasing on its posterior surface, 
 and commencing on its anterior surface. 
 
 Without committing a serious error, we can, how- 
 ever, apply the formula when t—\t\ because, in taking 
 the sum of the cubes ()+l 8 +2 3 +3 8 +. . .+ (A-l) 3 
 from 1 to (A— l) 8 it will only be necessary to take it 
 
 //A 8 
 
 from |~J to (h— l) 3 , which makes an error equal to 
 
 seen by replacing A by - in the expression -J — ^ ' !■ . 
 
 If the section of the charge, instead of being equal 
 
 to the section of the bore of the gun, is only -=, the 
 
 gases being developed freely in a space K times greater, 
 the density D will be diminished in an inverse ratio, 
 and we shall have 
 
 K tJ D 
 
 4tKd' 
 
 37. Application to practice. Thus it will be seen 
 that the density, and consequently the expansive force 
 of fired gunpowder can be determined at each instant 
 of combustion, either in the case in which the inflamma- 
 tion is considered instantaneous, or when considered 
 progressive. 
 
 The accuracy of the formulas was verified in France 
 some years since, in the course of a series of experiments 
 
PRACTICAL RESULTS. 67 
 
 to determine the influence which the size and density 
 of grains of powder exert upon the initial velocity of a 
 projectile. 
 
 There were six different sizes of grains tried, viz. : — 
 .26 in., .21 in., .18 in., .15 in., .10 in. (cannon), .05 in. 
 (musket) ; of each size there were six different densi- 
 ties, viz. : — 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, and four different 
 modes of manufacture, making 144 varieties of powder 
 in all. The instruments used were the ballistic pendu- 
 lum, the 4-pdr. gun pendulum, the mortar eprouvette, 
 and the infantry musket. 
 
 The results of calculation and direct experiment show 
 a remarkable agreement, and may be summed up as fol- 
 lows, viz.: — 
 
 1. With the 4-pdr. gun the high densities gave 
 greater velocities when combined with the smallest 
 grains, and vice versa, the low densities gave greater 
 velocities when combined with the largest grains. The 
 grains which gave the highest velocities possessed me- 
 dium size and density, or a density of 1.5 combined 
 with a diameter of 0.18 in. 
 
 2. With the mortar eprouvette, which fired a smaller 
 charge than the 4-pdr. gun, the fine-grained powder 
 gave almost invariably greater velocities than the 
 coarse. For a grain of .1 in. (or cannon size), the low- 
 est densities gave the best results, and for a grain of .05 
 in. (or musket size), the highest densities gave the best 
 results. 
 
 3. With the infantry musket, and a still smaller 
 charge, the superiority of fine grains was more marked 
 for all densities, and particularly so for the least. 
 
 It would appear from the foregoing, that the proper 
 
68 GUNPOWDER. GUN-COTTON. 
 
 size and density of grains of powder will depend on the 
 weight of the projectile to be moved, the size of the 
 charge, and the diameter and length of the bore in 
 which it is to be burned ; or, in other words, cannon 
 powder should have a coarser grain and higher density 
 than that intended for use in small -arms. 
 
 GUN-COTTON. 
 
 38. Gun-cotton, or pyroxiie. The action of nitric acid 
 on such vegetable substances as saw-dust, linen, paper, 
 and cotton, is to render them very combustible. In 
 their natural state these substances are almost entirely 
 composed of lignine, the constituents of which are oxy- 
 gen, hydrogen, and carbon ; nitric acid furnishes nitro- 
 gen, a substance which enters into the composition of 
 nearly all explosive bodies. 
 
 Gun-cotton was discovered by Prof. Schonbein, and 
 published to the world in 1846. His method of pre- 
 paring it consists in mixing three parts of sulphuric 
 acid, sp. grav. 1.85, with one part of nitric acid, sp. gr. 
 1.45 to 1.50 ; and when the mixture cools down to be- 
 tween 50° and 60° Fahr., clean rough cotton, in an open 
 state, is immersed in it ; when soaked, the excess of acid 
 is poured off, and the cotton pressed tightly to remove 
 as much as possible of what remains. The cotton is 
 then covered over and left for half an hour, when it is 
 again pressed, and thoroughly washed in running water 
 to remove all free acid. After being partially dried by 
 pressure, it is washed in an alkaline solution made by 
 dissolving one ounce of the carbonate of potash in a 
 gallon of water. The free acid being thus expelled, it 
 
GUN-COTTON. 69 
 
 is placed in a press, the excess of alkaline solution ex- 
 pelled, and the cotton left nearly dry. It is then 
 washed in a solution of pure nitrate of potash, one 
 ounce to the gallon, and being again pressed, is dried at 
 a temperature of from 150° to 170°. 
 
 The sulphuric acid has no direct action on lignine, its 
 use in the preparation of pyroxile being to retain the 
 water abstracted from the cotton, and prevent the solu- 
 tion of the compound, which would take place, to a 
 greater or less extent, in nitric acid alone. 
 
 Cotton, in its conversion into an explosive substance, 
 increases very considerably in weight, owing to the for- 
 mation of a new and distinct chemical compound. 
 
 Gun-cotton, when properly prepared, explodes at a 
 temperature of about 380° Fahr. It will not, therefore, 
 ignite gunpowder, when loosely poured over it. 
 
 Under ordinary circumstances, the electric spark will 
 not explode it ; but if the fluid be retarded in its prog- 
 ress by being passed over the surface of a string mois- 
 tened with common water, and in contact with the cot- 
 ton, explosion will follow. 
 
 From the experiments of Major Mordecai, made at 
 Washington arsenal, in 1846, the following facts regard- 
 ing the use of this substance in the military service, 
 were ascertained: — 
 
 1. The projectile force, when used with moderate 
 charges in musket or cannon, is equal to that of about 
 twice its weight of the best gunpowder. 
 
 2. When compressed by hard ramming (as in filling 
 a fuze), it burns slowly. 
 
 3. By the absorption of moisture, its force is rapidly 
 diminished, but it is restored by drying. 
 
70 GUNPOWDEK. GUN-COTTON. 
 
 4. Its explosive force, or bursting effect, is in a high 
 degree greater than that of gunpowder. In this respect 
 the nature of gun-cotton assimilates much more to that 
 of the fulminates than to gunpowder. It is, conse- 
 quently, well adapted for many purposes in mining. 
 
 5. Gun-cotton, well prepared, leaves no perceptible 
 stain when a small quantity is burnt on white paper. 
 
 6. It evolves little or no smoke, as the principal resi- 
 due of its combustion is water and nitrous acid ; the lat- 
 ter is made sensible by its odor, and by its effects on the 
 barrel of a gun, which will soon be corroded by it, if 
 not wiped after firing. 
 
 7. In consequence of the quickness and intensity of 
 action of gun-cotton, when ignited, it cannot be used 
 with safety in our present fire-arms. An accident of 
 service, such as that of inserting two charges into a 
 musket before firing (which frequently occurs), would 
 cause the bursting of the barrel ; and it is probable that 
 the same result would be produced by regular service 
 charges, repeated a moderate number of times. 
 
 Within a few years, attempts have been made to in- 
 troduce gun-cotton into the Austrian field-artillery, as a 
 substitute for gunpowder; and for this purpose several 
 batteries of short, thick bronze guns have been prepared 
 for service. 
 
 ^ d ** 
 
PROJECTILES. 71 
 
 CHAPTER II. 
 '^tt* PROJECTILES. 
 
 39. Definition. A projectile is intended to reach and 
 strike, pass through, or destroy, a distant object; the 
 effect of a projectile varies with its form and the mate- 
 rial of which it is composed. 
 
 To destroy an object against which it is thrown, a 
 projectile should have certain hardness and tenacity; if 
 it be softer and less tenacious than the object, it will 
 spread out laterally, or break into pieces, and presenting 
 a greater surface, will meet with greater resistance, and 
 consequently penetrate less than if it had preserved its 
 primitive form. Great density is also favorable to 
 penetration, inasmuch as it gives a projectile a greater 
 mass for an equal surface. 
 
 40. Material!. Stone, lead, wrought and cast iron 
 are materials, each possessing peculiar advantages for 
 projectiles, according to the circumstances under which 
 they are fired, and the objects against which they are 
 used. 
 
 Stone. Stone projectiles were used before the inven- 
 tion of gunpowder, and very generally after it, until the 
 year 1400, when the French made them of cast iron. 
 
 The defects of stone as a material for projectiles, are 
 a want of density and tenacity, which requires it to be 
 used in large masses, and fired with comparatively small 
 charges of powder. The effect of stone balls against 
 
72 PROJECTILES. 
 
 the walls of ancient cities was very great, but against 
 modern fortifications, where the walls are sustained by 
 large masses of earth, their effect is very slight. Until 
 quite lately, bronze guns, throwing stone balls of enor- 
 mous calibre, were used by the Turks in defending the 
 passage of the Dardanelles. It is stated that when the 
 English fleet, under Admiral Duckworth, forced the 
 passage of these straits, a stone ball weighing 800 lbs. 
 struck and nearly destroyed the English admiral's ship, 
 and that one hundred men were killed and wounded 
 by it. 
 
 Lead. Lead as a material for projectiles, possesses 
 the essential quality of density ; but it is too soft to be 
 used against very resisting objects, since it is flattened 
 even against water. 
 
 From its softness and fusibility, large projectiles of 
 this material are liable to be disfigured, and partially 
 melted, by the violent shock and great heat of large 
 charges of powder. Its use is chiefly confined to small- 
 arms and case-shot, which are generally directed against 
 animate objects. These defects of lead may be correct- 
 ed, in a measure, by alloying it with tin, antimony, <fcc. 
 
 Wrought iron. When great strength and density, 
 combined, are required in a projectile, wrought iron may 
 be used, but it is generally attended with considerable 
 expense. 
 
 Cast iron. The introduction of cast iron, for large 
 projectiles, was an important step in the improvement 
 of artillery, as it unites in a greater degree than any 
 other material, the essential qualities of hardness, 
 strength, density, and cheapness ; it is exclusively used 
 for this purpose in the United States' service. 
 
CLASSIFICATION. 73 
 
 Compound. Compound projectiles are sometimes 
 made so as to combine the good and correct the bad 
 qualities of different metals. Thus, at the siege of 
 Cadiz, cast-iron shells filled with lead, forming projec- 
 tiles of great strength and density, were thrown from 
 mortars to a distance of three miles and three quarters. 
 
 For rifle-cannon, projectiles are made occasionally of 
 cast iron, and covered with a soft coating of lead, or 
 other soft metal, to obviate the serious results that 
 might arise from the wedging of the flanges in the 
 grooves of the gun. Such is the construction of Arm- 
 strong's projectile in England, and Sawyer's and others, 
 in this country. 
 
 In the rifle-cannon lately used by the French army in 
 Italy, it is stated that the flanges which projected into 
 the grooves of the bore were made of tin. 
 
 Considerable success has also been attained in uniting 
 cast iron and wrought iron, and cast iron and soft metal, 
 in such manner as to attain the strength of one metal, 
 and the softness and expansibility of the other. 
 
 41. cias§iflcation. Projectiles may be classified ac- 
 cording to their form, as spherical and oblong. 
 
 Spherical projectiles. Spherical projectiles are com- 
 monly used in smooth-bored guns, and for this purpose 
 possess certain advantages over those of an oblong 
 form : 1. They present a uniform surface to the resist- 
 ance of the air as they turn over in their flight. 2. For 
 a given weight they offer the least extent of surface to 
 the resistance of the air. 3. The centres of figure and 
 inertia coincide. 4. They touch the surface of the bore 
 at only one point; they are therefore less liable to 
 wedge in the bore, and endanger the safety of the piece. 
 
74 PROJECTILES. 
 
 5. Their rebounds on land and water being certain and 
 regular, they are well suited to rolling and ricochet 
 firing. 
 
 Oblong projectiles. The great improvements which 
 have been made within the last few years in the accu- 
 racy and range of cannon and small-arms, consist simply 
 in the use of the oblong instead of the spherical form 
 of projectile. 
 
 The superiority of the oblong form has been long 
 known, and for many years used in the sporting rifles 
 of this country; but serious obstacles have always 
 stood in the way of its general adoption into the mili- 
 tary service. 
 
 To attain accuracy of flight and increase of range with 
 an oblong projectile, it is necessary that it should move 
 through the air in the direction of its length. Though 
 experience would seem to show that the only sure 
 method of effecting this, is to give it a rapid rotary 
 motion around its long axis by the grooves of the rifle, 
 numerous trials have been, and are now being made, to 
 produce the same effect with smooth-bored arms. 
 
 Centre of gravity, <&c. One of the simplest plans 
 used for this purpose, is to place the centre of gravity, 
 or inertia, in advance of the centre of figure, or resist- 
 ance. If these points be situated in the long axis of 
 the projectile, as they should be, the forces of propul- 
 sion and resistance, which act in opposite directions, 
 will cause it to coincide with the line of flight. 
 
 This plan was tried on a hollow projectile in the time 
 of Louis XIV., by dividing the cavity into two com- 
 partments by a partition, and filling the front one with 
 bullets, and the rear one with powder ; but the flight 
 
SOLID PKOJECTILES. 75 
 
 of these projectiles was uncertain and irregular, and it 
 was observed that some of them burst in* the air, and 
 that others struck the object sidewise. 
 
 Another plan of this kind, proposed by Thiroux, is 
 to make the projectile very long, with its rear portion 
 of wood, and its point of lead or iron, somewhat after the 
 manner of an arrow ; but it does not appear that that 
 method has ever been submitted to the test of practice. 
 
 Chain-ball. To arrest the motion of rotation of an 
 oblong projectile, thrown under high angles, and with 
 a moderate velocity, it has been proposed to attach a 
 light body to its posterior portion, by means of a cord 
 or chain, which will offer a resistance to the flight of 
 the projectile, and cause it to move with its point fore- 
 most. 
 
 Nail-ball. This is a round projectile, and has an iron 
 pin projecting from it to prevent it from turning in the 
 bore of the piece. 
 
 Grooved balls. Attempts have also been made to give 
 an oblong projectile a motion of rotation around its 
 long axis, by cutting spiral grooves on its base for the 
 action of the charge, or by cutting them on the forward 
 part for the action of the air. These plans have not 
 succeeded in practice, for the reason, perhaps, that the 
 projectile naturally turns over end for end, and the air 
 and charge do not act on the grooves with sufficient 
 promptness, energy, and certainty to prevent it. 
 
 42. Solid shot. Projectiles may be further classified 
 according to their structure and mode of operation, as 
 solid, hollow and case shot. 
 
 Solid projectiles. Solid projectiles are used in guns 
 and small-arms, and produce their effect by impact 
 
76 PROJECTILES. 
 
 alone. When used in heavy guns they are known as 
 solid shot, round shot, or shot. They are made of cast 
 iron, and on account of their great strength and density, 
 and the comparatively large charges of powder with 
 which they are fired, are used when great range, accu- 
 racy, and penetration are required. They are the only 
 projectiles that can be used with effect against very 
 strong stone walls, or floating batteries covered with 
 wrought-iron plates. Solid shot for guns are classified 
 according to their weight, which, in the United States' 
 land service, is as follows, viz. : 
 
 Field service, 6 and 12 pounders. 
 
 Siege service, 12, 18, and 24 pounders. 
 
 Sea-coast service, 32 and 42 pounders. 
 
 Solid shot for columbiads are classified according to 
 the diameter of the bore, as 8 and 10 inch solid shot. 
 
 43. Bullets. The object of small-arms is to attain 
 animate objects ; their projectiles are, therefore, made 
 of lead, and are generally known as bullets. They are 
 both round and oblong ; but in consequence of the great 
 improvements that have been made of late, in adapting 
 the principle of the rifle to small-arms, the oblong ball 
 is now very generally used in all military services, the 
 round bullet being chiefly retained for use in case-shot. 
 
 Hound bullets. Round bullets are denominated by 
 the number contained in a pound ; this method is often 
 used to express the calibre of small-arms ; as, for in- 
 stance, the calibre of the old musket was 17 to the 
 pound, and the rifle was 32. In 1856, these two calibres 
 were replaced by one of 24 to the pound, that of the 
 new rifle musket. The number is sometimes prefixed 
 to the word gauge, in which case the rifle-musket would 
 
SHELLS. 77 
 
 be called a 24:-gauge gun. This mode, however, is prin- 
 cipally used to designate sporting arms. 
 
 The oblong bullet is denominated by its diameter 
 and weight ; for instance, the new rifle-musket ball has 
 a diameter of 0.58 in., and weighs 540 grains. 
 
 Oblong bullet. The oblong bullet at present used in 
 
 v~ v the United States' service, is composed 
 
 / \ of a cylinder surmounted by a conoid 
 
 / \ — the conoid being formed of the arcs 
 
 I ~~~~^p — ---._.. of three circles. The cylinder has 
 C y three grooves cut in it, in a direction 
 
 i ' \ f\ perpendicular to its axis, to hold the 
 
 Fig. 9. grease necessary for lubricating the 
 
 bore of the piece in loading, and possibly to guide the 
 bullet in its flight, after the manner of the feathers of 
 an arrow. 
 
 A conical cavity is formed in the bottom, in which 
 the gas of the charge expands, and forces the sides 
 of the bullet into the grooves or rifles of the gun. 
 From these grooves it receives a rotary motion around 
 its long axis, which prevents it from turning over in 
 its flight. 
 
 44. Sheiig. Under the head of hollow shot are includ- 
 ed shells for guns, howitzers, and mortars, and hand and 
 rampart grenades. These projectiles are all made of 
 cast iron; and for guns and field howitzers their cali- 
 bres are expressed by the weight of the equivalent 
 solid shot, as 12, 24, and 32 pound shells ; and for 
 all other howitzers and mortars, by the diameter of 
 the bore of the piece, as 8 and 10 inch shells. 
 
 Shells have less strength to resist a shock, they are 
 therefore fired with a smaller charge of powder, than 
 
78 PKOJECTILES. SHELLS. 
 
 solid shot. Their weight, and consequent mean den- 
 sity, is generally about two-thirds that of a solid shot 
 of the same size. 
 
 Shells act both by impact amd explosion, and are 
 used against animals and such inanimate objects as 
 will not cause them to break on striking. 
 
 The principal parts of a spherical shell are : 1. The 
 canity — the shape of which is similar to and concentric 
 with the exterior. The use of the cavity is to contain 
 a bursting charge of powder, if the object be merely 
 to destroy by explosion; or a bursting charge and 
 incendiary composition, if the object be to destroy 
 by explosion and combustion together. The size of 
 the cavity should be as large as possible, to produce 
 the greatest explosive effect ; but as the shell should 
 have sufficient strength to resist the shock of the dis- 
 charge, and sufficient weight to overcome the resistance 
 of the air, the size of the cavity will necessarily be sub- 
 ordinate to these conditions, which fix the thickness of 
 the metal. 2. The fuze-hole, which is used in inserting the 
 bursting charge, and to hold the fuze which communi- 
 cates fire to it. As the presence of the fuze-hole dimin- 
 ishes the effect of the bursting charge, the diameter of 
 its orifice should be as small as possible. 3. The ears 
 are two small recesses made near the fuze-holes of all 
 shells larger than a 42-pound er, for the purpose of in- 
 serting the " hooks," and lifting the shells up to the 
 bore of the piece in loading. A small hole is sometimes 
 made in the upper hemisphere of shells, for the purpose 
 of charging them after the fuze is driven ; but late im- 
 provements in the construction of the fuze allow it to be 
 dispensed with, so that the powder can now be poured 
 
OF THE 
 
 UNIVERSIl 
 
 GRENADES. 
 
 directly through the fuze-plug, and the charging can be 
 deferred until the moment of loading. 
 
 Fig. 10 represents a mortar-shell, and fig. 11 a shell 
 used in a gun or sea-coast howitzer. The mortar-shell 
 is fired with a lighter charge of powder than the gun- 
 shell, and has therefore less thickness of metal. 
 
 The fuze-hole of the gun-shell, is reinforced with 
 metal, so that the fuze will not be driven in by the force 
 of the discharge. This reinforce serves, in a measure, to 
 compensate for the metal taken out of the fuze-hole, and 
 renders the shell more concentric. 
 
 
 
 
 
 
 
 
 a'. .Fuze-hole. 
 
 b. .Reinforce. 
 
 c. .Cavity. 
 
 d. .Sides, or thick- 
 
 ness of metal. 
 e . . Ears. 
 
 Kg. 10. 
 
 Fig. 11. 
 
 45. Grenades. The hand grenade, as its name indi- 
 cates, is a projectile thrown from the hand, against 
 troops in mass. 
 
 The particular projectile used for this purpose, in 
 our service, is the 6-pounder spherical case-shot. 
 
 Rampart Grenade. Rampart grenades are intended 
 to be rolled down the rampart of a work, to protect a 
 breach against the attack of a storming column. Shells 
 of any size will answer for this purpose, and particu- 
 larly those which are unserviceable for ordinary pur- 
 poses. 
 
 Grenades are filled with a bursting charge, and are 
 
80 
 
 PROJECTILES. CASE-SHOT. 
 
 armed with a short fuze,* which is lighted by a match 
 in the hands of the grenadier immediately before it is 
 thrown. They act by the force of their explosion 
 alone. 
 
 46. Ca§e-shot. Case-shot are a collection of small pro- 
 jectiles enclosed in a case or envelope. The envelope is 
 intended to be broken in the piece by the shock of the 
 discharge, or at any point of its flight, by a charge of 
 powder, enclosed within it ; in either case, the contained 
 projectiles continue to move on after the rupture, but 
 scatter out into the form of a sheaf or cone, so as to 
 cover a large surface and attain a great number of ob- 
 jects. These projectiles can only be used with effect 
 against animate objects situated at a short distance from 
 the point of rupture. 
 
 The three principal kinds of case-shot in use are 
 grape \ canister, and spherical case-shot, or shrapnel. They 
 are adapted to all guns and howitzers 
 below those of 10- inch calibre, and re- 
 ceive their name from the pieces in 
 which they are used. 
 
 Grape-shot. A grape-shot is com- 
 posed of nine small cast-iron balls, dis- 
 posed in three layers of three balls 
 each. Formerly the balls were held 
 together by a covering of canvas and 
 network of twine; but the present 
 method is more simple and durable. 
 
 * Ketchum's hand grenade, which has lately been introduced into the American 
 service, is a small, oblong percussion shell, which explodes on striking a slightly 
 resisting object. To prevent accidents, the "plunger," or piece of metal which 
 communicates the shock to the percussion cap is not inserted in its place until the 
 moment before the grenade is thrown. 
 
CASE-SHOT. 
 
 81 
 
 The parts of a stand of grape are, two plates, #, a, see 
 Fig. 12, for the top and bottom layers; two rings, Z>, b, 
 for the intermediate layer, and a screw-bolt, <?, which 
 passes through the plates and unites the whole. A han- 
 dle is formed by passing a piece of rope-yarn through 
 two holes in the upper plate, and tying the ends into 
 knots to prevent them from pulling out. 
 
 Grape-shot are used in all except the field and moun- 
 tain services. 
 
 Canister-shot* A canister-shot for a gun contains 27 
 small cast-iron balls, arranged in four layers, the top of 
 6, and the remainder of 7 each. A canister-shot for a 
 howitzer contains 48 small iron balls, in 4 layers of 12 
 each. For the same calibre, it will be seen that the 
 balls used in canister-shot are smaller than those used 
 in grape-shot. The envelope is a 
 tin cylinder, closed at the bottom 
 by a thick cast-iron plate, and at the 
 top by one of sheet-iron. The plates 
 are kept in place by cutting the 
 edges of the cylinder into strips 
 about 0.5 inch long, and lapping 
 them over the plates. To give more 
 solidity to the mass, and prevent 
 the balls from crowding upon each 
 other when the piece is fired, the interstices are closely 
 packed with sawdust. The handle is made of wire, 
 and attached to the thin plate at the top. 
 
 Canister-shot are used in the field, mountain, siege, 
 and sea-coast services. 
 
 c 
 
 W> 
 
 
 jo 
 
 
 m 
 
 Fior 13. 
 
 * The balls for canister for bronze rifle-guns are made of lead, or enclosed in a 
 case of some soft material, to avoid injury to the surface of the bore. 
 6 
 
82 PROJECTILES. CASE-SHOT. 
 
 It is stated that canister-shot were first used in the 
 defence of Constantinople, about the middle of the 15 th 
 century. 
 
 Spherical case-shot. Though projectiles similar to 
 spherical case-shot were used in France as early as the 
 time of Louis XIV., the credit of perfecting them is 
 due to Colonel Shrapnel of the British army. They 
 were first successfully used by the English against the 
 French, in the Peninsular war. 
 
 The envelope in the spherical case-shot, is a thin cast- 
 iron shell, the weight of which, when empty, is about 
 one half that of the equivalent solid 
 shot. To prepare this shot, it is 
 first filled with round musket-balls, 
 17 to the lb., and the interstices are 
 then filled up by pouring in melted 
 sulphur or resin ; the object of which 
 Fig. 14. is to solidify the mass of bullets, and 
 
 prevent them from striking, by their inertia, against the 
 sides of the case and cracking it, when the piece is fired. 
 A hole is bored through the mass of sulphur and bullets, 
 to receive the bursting charge; and, in order not to 
 displace too many bullets, and not to scatter them too 
 far when the shot bursts, the bursting charge should 
 only be sufficient to produce rupture. 
 
 If the iron, of which the case is made, were always 
 of suitable quality, and the cavity filled with bullets 
 snugly packed in, there would be no necessity for sul- 
 phur to prevent accidents. In this case, it would not 
 be necessary to remove any of the bullets, as the burst- 
 ing charge would be disseminated through the inter- 
 stices ; and the difficulty, which now sometimes arises 
 
 Ifin^ 
 
 IP- 
 
BAK-SH0T. 83 
 
 from their adhering to fragments of the case, would be 
 entirely obviated. 
 
 To increase the effect of a small bursting charge, the 
 lower portion of the fuze-hole, b, fig. 14, is partially 
 closed, by screwing into it a disk perforated with a 
 small hole for the passage of the flame from the fuze. 
 The spherical case-shot mostly used for field service is 
 the 12-pounder; it contains about 80 bullets; its burst- 
 ing charge is 1 oz. of powder ; and it weighs when fin- 
 ished 11.75 lbs., — nearly as much as a solid shot of the 
 same calibre. 
 
 The rupture of a spherical case-shot may be made to 
 take place at any point of its flight ; and in this re- 
 spect it is superior to canister and grape-shot, which 
 begin to separate the moment they leave the piece. 
 
 47. Bar-shot. Bar-shot consist of two hemispheres, or 
 two spheres, connected together by a bar of iron ; the 
 motion of rotation which these projectiles assume in 
 flight, renders them useful in cutting the masts and 
 rigging of vessels ; but, as they are very inaccurate, 
 they are only employed at short distances. They are 
 very little used, however, at the present day. 
 
 Chain-shot only differ from bar-shot in the mode of 
 connection, which is a chain, instead of a bar. 
 
 48. Percussion bullets. Percussion bullets may be 
 made by placing a small quantity of percussion powder, 
 
 enclosed in a copper envelope, in the point 
 of an ordinary rifle-musket bullet, or by 
 casting the bullet around a small iron tube, 
 which is afterward filled with powder and 
 surmounted with a common percussion-cap. 
 ^i^^p 5 * 1 The impact of the bullet against a sub- 
 
84 PROJECTILES. RUPTURE. 
 
 stance no harder than wood is found to ignite the 
 percussion charge or cap, and produce an effective 
 explosion. 
 
 These projectiles can be used to blow up caissons, and 
 boxes containing ammunition, at very long ditsances. 
 
 49. Carcasses. Carcasses are shells which have three 
 additional holes, of the same dimensions as the fuze- 
 hole, pierced at equal distances apart in their upper 
 hemispheres, with their exterior openings tangent to 
 the great circle perpendicular to the axis of the fuze- 
 hole. The object of a carcass is to set fire to wooden 
 structures, by the flame of the burning composition 
 which issues through the holes. 
 
 CHARGE OF RUPTURE OF SHELLS. 
 
 50. Plane of rupture. Suppose the cavity of the 
 shell to be spherical, and concentric with the exterior. 
 As soon as the enclosed charge of powder is inflamed, 
 the gases developed expand into the cavity, and the 
 expansive force increases until it is sufficient to over- 
 come the tenacity of the metal, and produce rupture ; 
 which will take place in the direction of least resistance, 
 or following a surface composed of lines normals to the 
 two surfaces. 
 
 Let R be the radius of the exterior, 
 and r the radius of the interior surface ; 
 0, the common centre of the two spheres ; 
 T, the tenacity of the material of which 
 the sphere is composed ; and />, the pres- 
 Fig. 16. sure on a un it f surface to overcome the 
 tenacity of the metal. 
 
PLANE OF KUPTURE. 85 
 
 Let C be the radius of the circle of rupture on the 
 interior surface. From the known properties of gases, 
 the pressure exercised on the area of this circle to pro- 
 duce rupture is equal to the components of all the nor- 
 mal pressures acting on the spherical segment of which 
 it is the base, taken perpendicularly to the plane of this 
 circle ; therefore npC 2 is the pressure of the gases which 
 tends to break the sphere. 
 
 Under this supposition, rupture should follow the 
 surface of the frustrum of a cone of which this circle is 
 the smaller base. 
 
 The surface of this frustrum is equal to the differ- 
 ence of the surfaces of two cones whose common apex 
 is at the centre of the sphere. The base of the smaller 
 is 2 7r CJ and its slant height r ; its surface therefore is 
 equal to nCr, The surface of the larger cone, whose 
 generatrix is the radius of the exterior sphere, will be 
 
 R 2 
 
 to the smaller as R 2 is to r 2 , and therefore -nCr— 
 
 their difference, or the area of the surface of rupture 
 
 will be equal to 
 
 -«(>-') 
 
 If the pressure of the gases acted normally to the sur- 
 face of the fracture, or in the direction of the tenacity, 
 this surface multiplied by T would give the total resist- 
 ance, which should be equal to the pressure of the 
 gases ; but it acts obliquely, and to produce rupture 
 should be increased by a quantity which depends on 
 the law of increase of the resistance due to the angle 
 which the pressure makes with the normal. Although 
 we cannot measure this resistance, it must be admitted 
 
86 PROJECTILES. RUPTURE. 
 
 that the effect to overcome is greatest when the power 
 is in the direction of the normal to the surface of 
 rupture. 
 
 We shall, therefore, have the relation, 
 
 pn C 2 = TnCr(~-l\+d 
 
 y =^)+ 
 
 Or, 
 
 In this expression the value of 6 is unknown ; but it 
 is easy to be seen that it diminishes as the direction of 
 the pressure approaches the normal, and when they 
 coincide 6 becomes 0. At the same time C increases, 
 and the value of p diminishes, until C becomes equal 
 to r, its maximum value. Therefore, the section of 
 easiest rupture of a hollow sphere passes through a 
 great circle, and the pressure which is in equilibrio with 
 the tenacity of the metal, will be given by the fore- 
 going formula, by making C= r, and (5=0 ; it will then 
 become, 
 
 When the pressure is less than this value of J9, the 
 sphere will resist its charge of powder; when it is 
 greater than this value, the sphere will burst. 
 
 The density of the gaseous products of the powder 
 necessary to burst the sphere can be easily found by 
 Rumford's formula : 
 
 Atmos. 
 
 L + 0.362d 
 
 p= 1.841 (905d) v 
 but d, or the density of the gaseous products, is equal 
 
LOSS OF GAS. 87 
 
 to their weight, or the weight of the bursting charge, 
 divided by the interior space of the sphere. 
 
 j w 
 Or, " **'*' 
 
 51. Lo§s of gas by fuze-hole. This loss of force by the 
 fuze-hole may be ascertained with sufficient accuracy, 
 provided we know from actual experiment the amount 
 of the loss from the fuze-hole of any one shell. 
 
 Let H and r be the exterior and interior radii of a 
 spherical projectile ; T, the tenacity of the metal ; i y the 
 radius of the fuze-hole ; ?//, the weight of powder neces- 
 sary to burst it under the supposition that there is no 
 loss of force at the fuze-hole ; w, the weight of powder 
 that is actually required to burst it. By the preceding 
 formulas we obtain the value of w'\ lu—w is therefore 
 the amount of loss by the fuze-hole. Take another pro- 
 jectile, and let w\ represent the charge which is neces- 
 sary to burst it, under the supposition that there is no 
 loss, and w / the weight that is found by experiment 
 necessary to burst it; w, — w\ will represent the loss. 
 We are at liberty to suppose the loss from the two 
 fuze-holes is proportional to the size of the holes, and 
 the density of the gases at the moment of rupture ; we 
 shall, therefore, have this proportion, 
 
 w—w' : w / —w/ : : #d : i*d t 
 
 i , / ,\#d 
 
 or, w=w -\-{w—w. j-tttt- 
 
 From the experiments made at Metz in 1835, it was 
 shown that this mode of estimating the loss of force by 
 
88 PKOJECTILES. FABRICATION. 
 
 the fuze-hole, was sufficiently exact for practical pur- 
 poses. 
 
 FABRICATION OF PROJECTILES. 
 
 52. Materials. Shot and shells should be made of 
 gray or mottled iron, of good quality. 
 
 Spherical case-shot should be made of the best quality 
 of iron, and with peculiar care, in order that they may 
 not break in the gun. 
 
 All projectiles should be cast in sand and not in iron 
 moulds, as those from the latter are generally not spher- 
 ical in form, nor uniform in size ; they are also full of 
 cavities, and are cracked by being heated. 
 
 Sand. The sand used should be silicious, of an angu- 
 lar grain, and moderate degree of fineness. It should 
 be mixed with a sufficient quantity of clay, so that, 
 when slightly moistened, it will retain its shape when 
 pressed in the hand. 
 
 Pattern. The pattern of a spherical projectile is corn- 
 Fig. 17. to draw it from the sand when 
 the half-niould is completed. The flasks which contain 
 the mould are made of cast iron, in two equal parts 
 united at their larger bases. 
 
 Moulding. This operation is performed by placing 
 the flat side of one of the hemispheres on the moulding 
 board, and covering it with a flask. Sand is then 
 
PATTERN. 89 
 
 poured into the flask, filling up the entire space between 
 it and the hemisphere, and well rammed. The flask is 
 then turned over, the hemisphere is withdrawn, and the 
 entire surface of the sand painted with coke-wash, and 
 dried. The remaining half of the mould is formed in 
 the same way, except that a channel for the introduc- 
 tion of the melted iron is made by inserting a round 
 stick in the sand before it is rammed, and withdrawing 
 it afterward. 
 
 This channel forms a sinking head, and supplies any 
 deficiency of metal in the mould. The inner orifice of 
 the sinking head should be situated at the side of the 
 mould, in order that the surface of the sand may not be 
 broken by the falling metal. 
 
 Hollow projectiles. Thus far, the operation of mould- 
 ing and casting solid and hollow projectiles are the 
 same. The cavity of a hollow projectile is made by in- 
 serting a core of sand, which is formed around a stem 
 fastened into the lower half of the mould. The stem is 
 hollow, and perforated with small holes to allow of the 
 escape of steam and gas generated by the heat of the 
 melted metal. It is also made of iron, but that part of 
 it which comes in contact with the melted iron, and 
 forms the fuze-hole, is coated with sand. 
 
 In pouring the melted iron into the mould with the 
 ladle, care should be taken to prevent scoria and dirt 
 from entering with it ; and, for this purpose, the sur- 
 face should be skimmed with a wooden stick. 
 
 Before the iron is fairly cooled, the flasks are open- 
 ed, and the sand knocked from the castings. After this, 
 the core is broken up and knocked out, and the in- 
 terior surface cleaned by a scraper. The sinking head 
 
90 PKOJECTILES. INSPECTION. 
 
 and other excrescences are knocked off, and the surface 
 smoothed in a rolling-barrel, or with a file, or chisel, 
 if necessary. The fuze-hole is then reamed out to the 
 proper size, and the projectile is ready for inspection. 
 
 INSPECTION OF PROJECTILES. 
 
 53. Object of inspection. The principal points to be 
 observed in inspecting shot and shells are, to see that 
 they are of proper size in all their parts ; that they 
 are made of suitable metal; and that they have no 
 defects, concealed or otherwise, which will endanger 
 their use, or impair the accuracy of their fire. 
 
 As it would be impracticable to make all projectiles 
 of exact dimensions, certain variations are allowed in 
 the fabrication. See Ordnance Manual. 
 
 Inspection of shot. The instruments are one large 
 and one small gauge, and one cylinder gauge ; the cylin- 
 der gauge has the same diameter as the large gauge, it 
 is made of cast iron, and is five calibres long. There 
 are also, one hammer with a conical point, six steel 
 punches, and one searcher made of wire. 
 
 The shot should be inspected before they become 
 rusty ; after being well cleaned, each shot is placed on 
 a table and examined by the eye to see that its surface 
 is smooth, and that the metal is sound and free from 
 seams, flaws, and blisters. If cavities or small holes 
 appear on the surface, strike the point of the hammer 
 or punch into them, and ascertain their depth with the 
 searcher ; if the depth of the cavity exceed 0.2 inch, 
 the shot is rejected ; and also if it appear that an at- 
 tempt has been made to conceal such defects by filling 
 them up with nails, cement, &c. 
 
INSPECTION. 91 
 
 The shot must pass in every direction through the 
 large gauge, and not at all through the small one ; the 
 founder should endeavor to bring the shot up as near 
 as possible to the large gauge, or to the true diam- 
 eter. 
 
 After having been thus examined, the shot are pass- 
 ed through the cylinder gauge, which is placed in an in- 
 clined position, and turned from time to time, to pre- 
 vent its being worn into furrows ; shot which slide or 
 stick in the cylinder are rejected. 
 
 Shot are proved by dropping them from a height of 
 twenty feet on a block of iron, or rolling them down an 
 inclined plane of that height, against another shot at 
 the bottom of the plane. 
 
 The average weight of the shot is deduced from that 
 of three parcels of twenty to fifty each, taken indiscrim- 
 inately from the pile ; some of those which appear to 
 be the smallest should also be weighed, and they are 
 rejected if they fall short of the weight expressed by 
 •their calibre, more than one thirty -second part. They 
 almost invariably exceed that weight. 
 
 Inspection of grape and canister shot. The dimen- 
 sions are verified by means of a large and small gauge, 
 attached to the same handle. The surface of the shot 
 should be smooth, and free from seams. 
 
 Inspection of hollow projectiles. The inspecting in- 
 struments are a large and small gauge for each calibre, 
 and a cylinder gauge for shells of eight inches and 
 under. 
 
 Calipers for measuring the thickness of shells at the 
 sides. 
 
 Calipers to measure the thickness at the bottom. 
 
92 PROJECTILES. INSPECTION. 
 
 Gauges to verify the dimensions of the fuze-hole, and 
 the thickness of the metal at the fuze-hole. 
 
 A pair of hand-bellows ; a wooden plug to fit the 
 fuze-hole, and bored through to receive the nozzle of 
 the bellows. 
 
 A hammer; a searcher ; a cold chisel ; steel punches. 
 
 Inspection. The surface of the shell and its exterior 
 dimensions, are examined as in the case of shot. The 
 shell is next struck with the hammer, to judge by the 
 sound whether it is free from cracks ; the position and 
 dimensions of the ears are verified ; the thickness of the 
 metal is then measured at several points on the great 
 circle perpendicular to the axis of the fuze-hole. The 
 diameter of the fuze-hole, which should be accurately 
 reamed, is then verified, and the soundness of the metal 
 about the inside of the hole is ascertained by inserting 
 the finger. 
 
 The shell is now placed on a trivet, in a tub contain- 
 ing water deep enough to cover it nearly to the fuze- 
 hole ; the bellows and plug are inserted into the fuze- 
 hole, and the air forced into the shell ; if there be any 
 holes in the shell, the air will rise in bubbles through 
 the water. This test gives another indication of the 
 soundness of the metal, as the parts containing cavities 
 will dry more slowly than other parts. 
 
 The mean weight of shells is ascertained in the same 
 manner as that of shot. Shot and shells rejected in the 
 inspection, are marked with an X made with a cold 
 chisel — on shot near the gate, and on shells near the 
 fuze-hole. 
 
PRESEKVATION. PILING. 93 
 
 PKESERVATION AND PILING OF BALLS. 
 
 54. lackering. Projectiles should be carefully lack- 
 ered as soon as possible after they are received. When 
 it is necessary to renew the lacker, the old lacker should 
 be removed by rolling or scraping the balls, which 
 should never be heated for that purpose. 
 
 Piling. Balls should be piled according to kind and 
 calibre, under cover if practicable, in a place where there 
 is a free circulation of air ; to facilitate which, the piles 
 should be narrow if the locality permits ; the width of 
 the bottom tier may be from twelve to fourteen balls, 
 according to the calibre. 
 
 Prepare the ground for the base of the pile by rais- 
 ing it above the level of the surrounding ground, so as 
 to throw off the water ; level it, ram it well, and cover 
 it with a layer of screened sand. Make the bottom of 
 the pile with a tier of unserviceable balls, buried about 
 two-thirds of their diameter in the sand ; this base may 
 be made permanent ; clean the base well, and form the 
 pile, putting the fuze-holes of the shells downward, in 
 the intervals, and not resting on the shells below. 
 
 The base may be also made of bricks, concrete, stone, 
 or with borders and braces of iron. 
 
 55. To find the number of balls in a pile. Multiply 
 the sura of the three parallel edges by one-third of the 
 number in a triangular face. 
 
 In a square pile, one of the parallel edges contains 
 but one ball; in a /triangular pile, two of the edges 
 have but one ball in each. 
 
94 PEOJECTILES. EOCKETS. 
 
 The number of balls in a triangular face is ^ ~*~ , 
 
 n being the number in the bottom row. 
 
 The sum of the three parallel edges in a triangular 
 pile is n -\-2 ; in a square pile, 2n-\-l ; in an oblong pile, 
 3JV-\-2n—2 ; N being the length of the top row, and n 
 the width of the bottom tier; or 3m— n-\-\; m being 
 the length, and n the width of the bottom tier. 
 
 If a pile consist of two joined at right angles, calcu- 
 late the contents of one as a common pile, and the other 
 as a pile of which three parallel edges are equal. 
 
 THEORY AND CONSTRUCTION OF ROCKETS. 
 
 56. structure, A rocket is a projectile which is set in 
 motion by a force residing withjn itself; it therefore 
 performs the two-fold function of piece and projectile. 
 
 It is essentially composed of a strong case of paper or 
 wrought iron, enclosing a composition of nitre, charcoal, 
 and sulphur — the same as gunpowder, except that the 
 ingredients are proportioned for a slower rate of com- 
 bustion. If penetration and range be required, its head 
 is surmounted by a solid shot / if explosion and incen- 
 diary effect, by a shell or spherical case-shot, to which is 
 attached a fuze, which is set on fire when it is reached 
 by the flame of the burning composition. The base is 
 perforated by one or more vents for the escape of the gas 
 generated within, and sometimes with a screw-hole to 
 which a guide-stick is fastened. 
 
 The disposition of the different parts will be readily 
 understood by reference to the subjoined figure, which 
 
MOTION. 95 
 
 represents a section through the long axis of a Congreve 
 rocket. 
 
 Fig. 18. 
 
 57. uiotion. A rocket is set in motion by the reaction 
 of a rapid stream of gas escaping through its vents. If 
 it be surrounded by a resisting medium, the atmosphere 
 for instance, the particles of gas, as they issue from the 
 vent, will impinge against and set in motion certain par- 
 ticles of air, and the force expended on the inertia of 
 these particles will react and increase the propelling 
 force of the rocket. It follows, therefore, that, though 
 a rocket will move in vacuo, its propelling force will 
 be increased by the presence of a resisting medium. 
 Whether the effect will be to accelerate the rocket de- 
 pends upon the relation between the resistance which 
 the medium offers to the motion of the gas, and that 
 which it offers to the motion of the rocket. 
 
 Vent. As the rate of combustion of the composition 
 is independent of the pressure of the gas in the bore, it 
 follows, that if the size of the vent be contracted, the 
 flow of gas through it will be accelerated. The strength 
 of the case, and the friction of the gas, which increases as 
 the vent diminishes, alone limit the reduction of the 
 size of the vent. 
 
 For vents of the same size, but of different shapes, 
 that one which allows the gas to escape most freely, 
 will be most favorable to the flight of the rocket. A 
 conical form of vent, with the larger orifice next to the 
 bore, will allow the gas to escape more rapidly than 
 
96 PROJECTILES. ROCKETS. 
 
 one of cylindrical form. This may be shown by burn- 
 ing portfire composition in tubes with different-shaped 
 vents. It will be found that the sparks from a conical 
 vent will be thrown much higher than those from a 
 cylindrical vent ; the relative heights depending on the 
 slope of the sides of the conical vent. 
 
 Bwe. As the composition of a rocket burns in 
 parallel layers of uniform thickness, the amount of gas 
 generated in a given time, or the velocity of its exit 
 from the case, depends on the extent of the inflamed 
 surface. 
 
 Experience shows that to obtain the required sur- 
 face of inflammation, it is necessary to form a long 
 cavity in the mass of the composition. This cavity is 
 called the lore. In small rockets, the bore is formed by 
 driving the composition around a spindle which is after- 
 ward withdrawn ; but in the large ones, the composition 
 is driven into the case in a solid mass by a powerful 
 hydrostatic press, and then bored out with a bit. In 
 all rockets the bore should be concentric with the case ; 
 its shape should be made conical to facilitate the draw- 
 ing out of the spindle, and to diminish the strain on the 
 case near its head, by reducing the amount of surface 
 where the pressure on the unit of surface is greatest. 
 
 Nature of movement Suppose the rocket in a state 
 of rest, and the composition ignited; the flame imme- 
 diately spreads over the surface of the bore, forming 
 gas, which issues from the vent. The escape is slow in 
 the first moments, as the density of the gas is slight ; 
 but as the surface of the inflammation is large compared 
 to the size of the vent, the gas accumulates rapidly, and 
 its density is increased until the velocity of the escape 
 
GUIDING PRINCIPLE. 97 
 
 is sufficient to overcome the resistances which the 
 rocket offers to motion. These resistances are, inertia, 
 friction, the component of weight in the direction of 
 motion, and, after motion takes place, the resistance of 
 the air. 
 
 The constant pressure on the head of the bore accel- 
 erates the motion of the rocket until the resistance of 
 the air equals the propelling force ; after this, it will 
 remain constant until the burning surface is sensibly 
 diminished. When the gas ceases to flow, the rocket 
 loses its distinctive character, and becomes, so far as its 
 movement is concerned, an ordinary projectile. 
 
 The increase in the surface of combustion whereby 
 more gas is developed in the same time, and the dimi- 
 nution in the weight of the remaining composition, 
 cause the point of maximum velocity to be reached 
 with increased rapidity.. If the weight of the rocket be 
 increased, the instant of maximum velocity will be pro- 
 longed, but the amount will remain the same. A change 
 in the form of the rocket which increases the resistance 
 of the air, will have the effect to diminish the maximum 
 velocity. 
 
 The maximum velocity of French rockets, and the 
 distances at which they are attained, are given in the 
 following table : — 
 
 CALIBRE. DISTANCE. MAXM. VELOCITY. 
 
 2} inches, 134 yds. 278 yds. 
 
 3£ " 141 " 370 " 
 
 According to* the- calculations of Piobert, for small 
 rockets it takes about f- second for the gas to attain its 
 maximum velocity of 850 yds. 
 
 58. Ouiding principle. The propelling force of a 
 
 7 
 
98 PEOJECTILES. KOCKETS. 
 
 rocket changes its direction with the axis along which 
 it acts ; it follows, therefore, that without some means 
 of giving stability to this axis, the path described will 
 be very irregular, so much so, at times, as to fold upon 
 itself; and instances have been known where these pro- 
 jectiles have returned to the point whence they started. 
 
 An example of this irregular motion may be seen in 
 "serpents," a species of small rockets without guide- 
 sticks. 
 
 The two means now used to give steadiness to the 
 flight of a rocket are, rotation, as in the case of a rifle- 
 ball, and the resistance of the air, as in an arrow. 
 
 Holds system. The first is exemplified in Hale's 
 rocket, where rotation is produced around the long axis 
 by the escape of the gas through five small vents situ- 
 ated obliquely to it. In his first arrangement, the in- 
 ventor placed the small vents in the base, surrounding 
 the large central vent, so that the resultant of the tan- 
 gential forces acted around the posterior extremity of 
 the axis of rotation. In 1855, this arrangement was 
 changed by reducing the number of the small vents to 
 three, and placing them at the base of the head of the 
 rocket. The rocket thus modified, and shown in fig. 20, 
 is the one now used by the United States government for 
 war purposes * 
 
 * It is said that Mr. Hale's latest improvement consists in placing the tan- 
 gential vents in a plane passing through the centre of gravity of the rocket, 
 
 and at right angles to the 
 
 axis. This is accomplished 
 
 by dividing the case into two 
 
 distinct parts, or rockets, by 
 
 -pjg 19 a perforated partition. The 
 
 composition in the front part 
 
 furnishes the gas for rotation, and that in the rear the gas for propulsion. See 
 
 fig 19. — New Resources of Warfare, by Scoff em. 
 
HOW FIKED. 
 
 99 
 
 Fig. 20. 
 a. .Bore and vent. 
 b . . Recess in the base of the head. 
 
 c. .Tangential vent (three). 
 
 d. .Head (solid). 
 
 Congrevds system. A Congreve rocket is guided by 
 a long wooden stick attached to its base. If any cause 
 act to turn it from its proper direction, it will be op- 
 posed by resistances equal to its moment of inertia and 
 the lateral action of the air against the stick. 
 
 The effect of these resistances w r ill be increased by 
 placing the centre of gravity near the head of the 
 rocket, and by increasing the surface of the stick. 
 
 In signal rockets, where the case is made of paper, 
 the stick is attached to the side by wrapping around 
 twine; and there is but one large vent, which is in the 
 centre of the case. 
 
 In war-rockets the stick is attached to the centre of 
 the base, and the large central vent is replaced by 
 several small ones near its circumference. See fig. 18. 
 The former arrangement is not so favorable to accuracy 
 as the latt3r, inasmuch as rotation will be produced if 
 the force of propulsion and the resistance of the air do 
 not act in the same line. 
 
 59. How fired. Rockets are generally fired from tubes 
 or gutters ; but should occasion require it, they may be 
 fired directly from the ground, care being taken to 
 raise the forward end by propping it up with a stick or 
 stone. As the motion is slow in the first moments of 
 its flight, it is more liable to be deviated from its 
 
100 PROJECTILES. ROCKETS. 
 
 proper direction at this time than any other ; for this 
 reason the conducting tube should be as long as prac- 
 ticable, say from five to ten feet.* 
 
 60. Form of trajectory. Take that portion of the 
 trajectory where the velocity is uniform. The weight 
 of the rocket applied at its centre of gravity, and acting 
 in a vertical direction, and the propelling force acting in 
 the direction of its length, are two forces the oblique 
 resultant of which moves the rocket parallel to itself; 
 but the resistance of the air is oblique to this direction, 
 and acting at the centre of figure, a point situated be- 
 tween the centre of gravity and extremity of the guide- 
 stick, produces a rotation which raises the stick, and 
 thereby changes the direction in which the gas acts. 
 As these forces are constantly acting, it follows that 
 each element of the trajectory has less inclination to 
 the horizon than the element of an ordinary trajectory 
 in which the velocity is equal. 
 
 When the velocity is not uniform, the position of 
 the centre of gravity has a certain influence on the form 
 of the trajectory. To understand this, it is necessary to 
 consider that the component of the resistance of the 
 air which acts on the head of the rocket is greater than 
 that which acts on the side of the stick. It is also ne- 
 cessary to consider that the pressure of the inflamed 
 gas acts in a direction opposite to the resistance of the 
 air, that is to say, from the rear to the front, and that 
 the centre of gravity is near the rear extremity of the 
 case. 
 
 * Mr. Hale has suggested a means of using a short tube, by applying a pressure 
 to the rfccket to retain it in its place until the^ gas has acquired the requisite 
 velocity. 
 
TOEM OF TRAJECTORY. 101 
 
 At the beginning of the trajectory, when the motion 
 of the rocket is accelerated, its inertia is opposed to 
 motion, and being applied at the centre of gravity, 
 which is in rear of the vent, the point of application 
 of the moving force, it acts to prevent the rocket from 
 turning over in its flight. But when the composition 
 is consumed, the centre of gravity is thrown further to 
 the rear, and the velocity of the rocket is retarded, the 
 inertia acts in the opposite direction, and the effect will 
 be, if the centre of gravity or inertia is sufficiently far 
 to the rear, to cause it to turn over in the direction of 
 its length. 
 
 If the rocket be directed toward the earth, this 
 turning over will be counteracted by the acceleration 
 of velocity due to the weight, and the form of the 
 trajectory will be preserved. 
 
 Effect of wind. When the wind acts obliquely to 
 the plane of fire, its component perpendicular to this 
 plane, acting at the centre of figure, will cause the 
 rocket to rotate around its centre of gravity. As the 
 centre of figure is situated in rear of the centre of grav- 
 ity, the point will be thrown toward the wind, and the 
 propelling force acting always in the direction of the 
 axis, the rocket will be urged toward the direction of 
 the wind. To make an allowance for the wind, in 
 firing rockets, they should be pointed toward the op- 
 posite side from which the wind comes, or with the 
 wind instead of against it. 
 
 If the wind act in the plane of fire from front to 
 rear, it will have the effect to depress the point, and 
 with it the elements of the trajectory in the ascending 
 branch, and elevate them in the descending branch ; as 
 
102 PEO JECTILES. ROCKETS. 
 
 the latter is shorter than the former, the effect of a 
 front wind will be to diminish the range. The converse 
 will be true for a rear wind. 
 
 61. History. Rockets were used in India and China 
 for war purposes before the discovery of gunpowder; 
 some writers fix the date of their invention about the 
 close of the ninth century. Their inferior force and ac- 
 curacy limited the sphere of their operations to incen- 
 diary purposes, until the year 1804, when v Sir William 
 Congreve turned his attention to their improvement. 
 This officer substituted sheet-iron cases for those made 
 of paper, which enabled him to use a more powerful 
 composition ; he made the guide-stick shorter and 
 lighter, and removed a source of inaccuracy of flight by 
 attaching the stick to the centre of the base instead of 
 the side of the case. He states that he was enabled by 
 his improvements to increase the range of 6-pdr. rock- 
 ets from 600 to 2,000 yards. Under his direction they 
 were prepared, and used successfully at the siege of 
 Boulogne and the battle of Leipsic. At the latter 
 place they were served by a special corps. 
 
 62. Advantages. The advantages claimed for rockets 
 over cannon are, unlimited size of projectile ; portabil- 
 ity; freedom from recoil; rapidity of discharge; and 
 the terror which their noise and fiery trail produce on 
 mounted troops. 
 
 The numerous conditions to be fulfilled in their con- 
 struction in order to obtain accuracy of flight, and the 
 uncertainty of preserving the composition uninjured for 
 a length of time, are difficulties not yet entirely over- 
 come, and which have much restricted their usefulness 
 for general military purposes. 
 
KIND USED. 103 
 
 63. Kind used. The two sizes of Hale's rockets in 
 use in the American service are, the 
 
 2-inch (interior diameter of case), weighing 6 lbs. ; and 
 3-inch " " " " 16 lbs. 
 
 Under an angle of from 4° to 5° the range of these 
 rockets is from 500 to 600 yds. Under an angle of 47° 
 the range of the former is 1,760 yds. and the latter 
 2,200. 
 
 O 
 
104 
 
 CANNON. 
 
 d%( <^- 
 
 1 
 
 CHAPTER III. 
 
 HISTORY OF CANNON. 
 
 MORTAR. 
 
 64. The terms cannon and ordnance are applied to all 
 heavy fire-arms which are discharged from carriages, in 
 contradistinction to email arms, which are discharged 
 from the hand. 
 
 65. Early cannon.* The 
 shape of the first cannon used, 
 after the invention of gunpow- 
 der was conical, internally 
 and externally resembling an 
 apothecary's mortar. They 
 Fi s- 21. were called mortars, bombards 
 
 and vases, 
 
 BOMBARD. 
 
 were fired at high angles ; and, in conse- 
 quence of the slow 
 burning of the pow- 
 der of that day, and 
 the conical shape of 
 the bore, the stone 
 balls which they pro- 
 Fig. 22. jected moved with 
 very little velocity and accuracy. 
 
 Perriere. To economize the action of the powder, and 
 give a more accurate direction to the projectile, the in- 
 terior space, or bore, was afterward made nearly cylin- 
 drical, from 4 to 8 calibres long ; it was terminated at 
 
 * Vide Thiroux. 
 
ANCIENT CANNON. 
 
 105 
 
 the bottom by a very narrow and deep chamber, the 
 object of which was to increase the effect of the powder, 
 by retarding the escape of the gas before it acted on 
 the projectile. These cannon were further improved by 
 making the bores perfectly cylindrical ; and were called 
 perrieres (fig. 23), from the fact that they fired stone 
 balls. They were principally employed to breach stone 
 walls, and for this purpose were fired horizontally. 
 
 PERRIERE. 
 
 Fig. 23. 
 
 66. Con§truction of early cannon. The first bom- 
 bards were made of bars of iron, bound together by 
 hoops, after the manner of the staves of a barrel. Fig. 
 22. Afterward they were made of wrought iron, and 
 finally of cast metal. Bronze guns were used in the 
 time of King John of France. 
 
 Among the earliest cannon are found those which 
 were loaded at the breech instead of the muzzle. One 
 of the methods is shown in Hg. 24, in which A repre- 
 sents a rectangular opening formed at the breech for the 
 purpose of receiving a movable chamber, C 9 which con- 
 tained the charge, and was held in its place by a key, 
 
 Fig 24. 
 
 D. Though these pieces possessed great facility in load- 
 
106 
 
 CANNON. ANCIENT GUNS. 
 
 ing, they were abandoned for want of strength and 
 solidity. 
 
 67. Ancient guns. The introduction of cast-iron pro- 
 jectiles, which are much stronger and denser than those 
 of stone, led to the invention of a new species of can- 
 non, called cuherins, which very nearly correspond in 
 construction and appearance to the guns of the present 
 day. The great strength of these pieces and their pro- 
 jectiles, permitted the use of a large charge of powder ; 
 and their introduction proved an important step in the 
 improvement of artillery. 
 
 CULVERIN. 
 
 OSSii 
 
 •2* 
 
 
 Pig. 25. 
 
 The idea was entertained by ancient artillerists — 
 founded on the relation which cannon were erroneously 
 supposed to bear to small arms — that the range increased 
 with the length of the piece ; and in consequence, many 
 culverins were made of enormous length. A remark- 
 able piece of this description still exists at Dover, Eng- 
 land, familiarly known as Queen Anne's pocket-piece. 
 While it carries a ball weighing only 18 lbs., it is more 
 than 25 feet long. 
 
 68. Ancient mortars. From the earliest days of ar- 
 tillery there existed short, chambered pieces, which 
 projected stone balls under great angles of elevation. 
 In 1478, an attempt was made to use in these pieces, 
 hollow projectiles filled with powder, to which was at- 
 tached a burning match to set the powder on fire ; but 
 it is probable that the accidents which accompanied 
 
CALIBKE. 
 
 107 
 
 their use caused them to be abandoned for the time. 
 In 1634, however, means were devised to overcome this 
 difficulty; and, thus perfected, these pieces were intro- 
 duced into the French service as a class of cannon now 
 known as mortars. 
 
 In the reign of Louis XIV., a great variety of mor- 
 tars were used ; and some of them, called Comminges, 
 after their inventor, threw bombs weighing 550 lbs. 
 
 69. Ancient howitzers. Early attempts were also 
 made to throw hollow projectiles from " perrieres," and 
 " culverins," or guns ; but great difficulties were expe- 
 rienced in loading them ; and the accidents to which 
 they were liable, as in the case of mortars, caused them 
 to be abandoned. Subsequently, however, the Dutch 
 artillerists conceived the idea of reducing their length, 
 so that the projectile could be inserted in its place by 
 hand; and, thus improved, these cannon rapidly came 
 into use, under the name of howitzers, from the Ger- 
 man, Haubitz. 
 
 70. Calibre. The calibre of a cannon is the diameter 
 of its bore expressed in inches, or the weight of the 
 shot corresponding to it.* Each nation early adopted 
 a series of calibres, decreasing in a geometrical pro- 
 gression. The principal series were the French, or 
 32-pounder, 16-pounder, 8-pounder, 4-pounder, and 
 
 * In some services the calibre refers to the size of the bore, in others, to the 
 size of the shot. In Germany, the projectile referred to is a stone ball. 
 
 TABLE OP CALIBRES IN AMERICAN SERVICE. 
 
 6-pd. 
 
 9-pd. 
 
 12-pd. 
 
 18-pd. 
 
 24-pd. 
 
 32-pd. 
 
 42-pd. 
 
 3.67" 
 
 4.2" 
 
 4.62" 
 
 5.2" 
 
 5.82" 
 
 6.4" 
 
 7.0" 
 
108 CANNON. - "MATERIEL. SYSTEM. 
 
 2-pounder; and the German, or 48-pounder, 24-pounder, 
 1 2-pounder, 6-pounder, 3-pounder, and Impounder. 
 
 71. Devices. Down to the time of the French revo- 
 lution, bronze cannon were highly ornamented with 
 carved figures representing some fanciful design, to- 
 gether with the national coat-of-arms and cypher of the 
 reigning monarch. Each piece also bore a particular 
 name borrowed from some animal or passion ; and 
 French cannon of the ,time of Louis XVI. bore the mot- 
 toes, " Nee pluribus impar," and " Ultima ratio regum." 
 That this custom of naming cannon is not entirely ob- 
 solete, is shown by a piece of singular shape and con- 
 struction, captured in the late war with Mexico, which 
 bears the title of "El Terror del Norte Americano." 
 
 72. " Hateriei."— System. The expression, "materiel 
 of artillery" embraces all cannon, carriages, implements, 
 ammunition, &c, necessary for artillery purposes, and 
 is used in contradistinction to "personnel of artillery" 
 which refers to the officers and men. The expression, 
 " system of artillery" refers to the character and arrange- 
 ment of the materiel of artillery, as adopted by a nation 
 at any particular epoch. 
 
 In the United States' service, the term " ordnance and 
 ordnance stores," embraces not only all the materiel of 
 artillery, but the swords, small arms, and accoutrements 
 used by infantry and mounted troops. 
 
 The principal qualities to be observed in establishing 
 a system of artillery are simplicity, mobility, and power ; 
 and the improvements which have been made in artil- 
 lery in the last four hundred years have had these quali- 
 ties steadily in view. 
 
 The American systems of field and siege artillery are 
 
FIRST SYSTEM. 109 
 
 chiefly derived from those of France ; it will, therefore, 
 be useful to the pupil to study the history of the latter, 
 and compare the successive steps of improvement which 
 have brought them to their present state of perfection * 
 
 73. First system. Toward the middle of the sixteenth 
 century, the various guns of the French artillery were 
 reduced to six. The weights of the balls correspond- 
 ing to these calibres were 33|, 15|, 7|, 2£, 1^, and f- lb. 
 respectively. This range of calibres was thought to be 
 necessary, for the reason that it required guns of large 
 calibre to destroy resisting objects, while guns of small 
 calibre were necessary to keep up with the movement 
 of troops. 
 
 Each of the five principal calibres was mounted on a 
 different carriage, and the ammunition, stores, and tools 
 were carried on different store-carts. 
 
 Three kinds of powder were used, viz. : large-grain, 
 small-grain, and priming, which were carried in barrels 
 of three sizes. 
 
 The axle-trees, which were of wood, varied for the 
 different wheels, as well as for the different guns. The 
 gun-carriages were without limbers, and had only two 
 wheels, the shafts being attached to the trails, which 
 often dragged along the ground. No spare wheels were 
 used, except for pieces of large calibre ; and for facility 
 of transportation these were put on an axle-tree, so as to 
 form a carriage. 
 
 With the exception of replacing injured wheels, all 
 repairs were made on the spot, from the resources of the 
 country, and no spare articles were carried with the 
 train. There was no established charge of powder for 
 
 * Vide New System of Field Artillery, by Captain Fave. 
 
110 CANNON. DIFFERENT SYSTEMS. 
 
 the guns ; although a weight equal to that of the shot 
 was generally used. 
 
 Such was the character of the artillery which accom- 
 panied the French armies up to the middle of the seven- 
 teenth century. 
 
 74. Second system. In the reign of Louis XIV., the 
 calibres of cannon were gradually changed by the in- 
 troduction of several foreign pieces. There were 48, 
 32, 24, 16, 12, 8, and 4 pdrs. ; and those of the same 
 calibre varied in weight, length, and shape. 
 
 Uniformity existed in general in each district com- 
 manded by a lieutenant-general of artillery, but the 
 cannon of one district differed from another. Each 
 district had (for the six kinds of cannon) six carriages, 
 with different wheels, and three kinds of limbers, with 
 different wheels, making nine patterns of wheels, with- 
 out counting those for the platform wagons used to 
 transport heavy guns, the ammunition carts, the trucks, 
 and the wagons for small stores and tools. 
 
 Spare carriages were carried into the field, but those 
 of one district would not fit the guns of another. There 
 was but one kind of powder, and this was carried in 
 barrels. The charge was usually two-thirds the weight 
 of the projectile, roughly measured. Besides this, the 
 powder often varied in strength according to the dis- 
 trict from which it came. 
 
 75. Vaiiere's system. In 1732, General Valiere abol- 
 ished the 32-pdr., as being heavy and useless, and gave uni- 
 formity to the five remaining calibres. Toward the end 
 of the 18th century, mortars, or Dutch howitzers, were 
 sometimes attached to the field trains ; for the latter, a 
 small charge, and calibre of 8 inches, were adopted. 
 
gribeatjval's system. Ill 
 
 There were also light 4-pdr. guns attached to each regi- 
 ment. Up to that time an army always carried with 
 it heavy guns (24-pdrs.), and light guns (4-pdrs.), which 
 were combined in the same park. 
 
 Valiere established a system of uniformity for cannon 
 throughout France ; but such was not the case with the 
 carriages and wagons used with them. Great exactness 
 was not then sought for, and there existed as many 
 plans for constructing gun-carriages as there were ar- 
 senals of construction. The axle-trees were made of 
 wood, the limbers were very low, and the horses were 
 attached in single file. 
 
 75. Gribcauvai's sy§tem. In 1765, General Gribeauval 
 founded a new system, by separating the field from the 
 siege artillery. He diminished the charge of field-guns 
 from a half to a third the weight of the shot, but as he 
 diminished the windage of the projectile at the same 
 time, he was enabled to shorten them and render them 
 lighter, without sensibly diminishing their range. 
 
 Field artillery then consisted of 12, 8, and 4 pdr. 
 guns, to which was added a 6-inch howitzer, still retain- 
 ing a small charge, but larger in proportion than that 
 before used. For draught, the horses were disposed in 
 double files, which was much more favorable to rapid 
 gaits. Iron axle-trees, higher limbers, and travelling 
 trunnion-holes, rendered the draught easier. The 
 adoption of cartridges, elevating screws, and tangent 
 scales, increased the rapidity and regularity of the fire. 
 Stronger carriages were made for the lighter guns, and 
 the different parts of all were made with more care, and 
 strengthened with iron work. Uniformity was estab- 
 lished in all the new constructions, by compelling all 
 
112 CANNON. DIFFERENT SYSTEMS. 
 
 the arsenals to make every part of the carriages, wagons, 
 and limbers according to certain fixed dimensions. By 
 this exact correspondence of all the parts of a carriage, 
 spare parts could be carried into the field ready made, 
 to refit. Thus an equipment was obtained which could 
 be easily repaired, and could be moved with a facility 
 hitherto unknown. 
 
 In order to reduce the number of spare articles neces- 
 sary for repairs, Gribeauval gave, as far as practicable, 
 the same dimensions to those things which were of the 
 same nature. 
 
 The excellence of this system was tested in the wars 
 of the French Republic and Empire, in which it played 
 an important part. 
 
 77. stock trail §y§tem. In 1827, the system of Gri- 
 beauval was changed by introducing the 24 and 32 pdr. 
 howitzers, lengthened to correspond with the 8 and 12 
 pdr. guns, and abolishing the 4-pdr. gun and 6-inch 
 howitzer. Afterward some important improvements 
 were made in the carriages, chiefly copied from the 
 English system ; the number for all field cannon was 
 reduced to two, the wheels of the carriage and limber 
 were made of the same size ; the weight of the limber 
 was reduced, and an ammunition chest placed on it ; the 
 method of connecting the carriage and limber was sim- 
 plified, and the operations of limbering and unlimbering 
 greatly facilitated ; and the two flasks which formed the 
 trail were replaced by a single piece, called the stock, 
 which arrangement allowed the new pieces to turn in a 
 smaller space than that required by the old ones. 
 
 78. JLouis Napoleon's system. In 1850, the present 
 Emperor of the French caused a series of experiments to 
 
RECENT IMPROVEMENTS. 113 
 
 be made, at the principal artillery schools of France, to 
 test the merits of a new system of field artillery pro- 
 posed by himself. The principal idea involved in this 
 system was, to substitute a single gun of medium weight 
 and calibre, capable of firing shot and shells, for the 8 
 and 12 pdr. guns and 24 and 32 pdr. howitzers, then in 
 use. The calibre selected was the 12 pdr. 
 
 The favorable results of all these experiments, and 
 the simplicity of the system, led to the adoption of this, 
 the Napoleon gun, as it is sometimes called, into the 
 French service ; and others of similar principle were in- 
 troduced into various European services, and also into 
 our own. As this piece unites the properties of gun 
 and howitzer, it is called canon-obusier, or gun-howitzer. 
 
 79. Recent improvement*. At no time since the dis- 
 covery of gunpowder, have such important improve- 
 ments been made in fire-arms, as within the past few 
 years. These improvements may be summed up as fol- 
 lows, viz. : — 
 
 1st. Improvement in the quality of cast iron, and the 
 consequent increase in the calibre of sea-coast cannon. 
 In 1820, the heaviest gun mounted on our sea-coast bat- 
 teries, was the 24-pdr. ; at present, the heaviest is a 
 15-inch gun, carrying a shell weighing 420 lbs. with 50 
 lbs. of powder. 2d. The use of wrought iron as a ma- 
 terial for fortress carriages, and for covering ships of war. 
 3d. The extensive introduction of shells in sea-coast de- 
 fences and naval warfare ; and spherical case-shot into 
 the field-service ; and, 4th. The successful application of 
 the rifle principle to small arms and cannon. 
 8 
 
114 CANNON. CONSTRUCTION. 
 
 CONSTRUCTION, Ac, OF CANNON. 
 
 80. Definition. A cannon is a heavy machine, 
 used to set projectiles in motion by means of gunpowder. 
 Its general form is that of a tube closed at one end. 
 
 81. Clas§iflcation. All cannon may be classified, 
 according to their nature, as guns, howitzers, and mor- 
 tars ; and, according to the uses to which they are 
 applied, as field, mountain, prairie, siege, and sea-coast 
 cannon. The recent introduction of rifle-cannon into 
 the military service, requires that a further distinction 
 should be made, between rifled and smooth-bored can- 
 non. How far this change will affect the distinction 
 now made between guns and howitzers, remains to be 
 determined by future experience. 
 
 In treating of cannon, it is proposed, in the first 
 place to discuss those parts and principles common to 
 all ; and, in the second place, to consider the peculiar 
 characteristics of each class and calibre. 
 
 A. .Cascable. 
 
 B. .First reinforce. 
 
 C. .Sec'd reinforce. 
 D.. Chase. 
 
 E. .Swell of the muz- 
 zle. 
 
 F. .Trunnions. 
 
 G. .Rimbases. 
 Fig. 26. H. .Bore. 
 
 82. Womenciatnre.* The coscohle is that part of 
 the gun in rear of the base of the breech ; it is com- 
 posed generally of the following parts: the knob, the 
 neck, the fillet, 
 
 * This nomenclature refers more particularly to guns of the old pattern, large 
 numbers of which will probably remain in service for some time to come. The 
 most recent models are characterized by an entire absence of mouldings and orna- 
 ments, and the elements, in most cases, are curved instead of right lines. The 
 modifications which it is necessary to make to suit the present nomenclature to the 
 new system, will readily suggest themselves to the mind cf the pupil. 
 
NOMENCLATURE. 115 
 
 The base of the breech is a frustum of a cone, or a 
 spherical segment, in rear of the breech. 
 
 The base-ring is a projecting band of metal adjoining 
 the base of the breech, and connected with the body of 
 the gun by a concave moulding. It serves as a point 
 of support for the breech sight, and rests upon the 
 head of the elevating screw. The ring is omitted in 
 guns of recent model. 
 
 The breech is the mass of solid metal behind the 
 bottom of the bore, extending to the rear of the base-ring. 
 
 The reinforce is the thickest part of the body of the 
 piece, in front of the base-ring. If there be more than 
 one reinforce, that which is next to the base-ring is 
 called the first reinforce / the other, the second rein- 
 force. 
 
 The chase is the conical part of the piece in front 
 of the reinforce. 
 
 The astragal and fillets, in field guns, and the chase- 
 ring in other pieces, are the mouldings at the front 
 end of the chase. 
 
 The neck is the smallest part of the piece, in front 
 of the astragal or chase-ring. 
 
 The swell of the muzzle is the largest part of the 
 piece in front of the neck. It is terminated by the 
 muzzle mouldings, which, in field and siege guns, con- 
 sist of the lip and fillet. In sea-coast guns, and heavy 
 howitzers and columbiads, there is no fillet. In field 
 and siege howitzers, and in mortars, a muzzle band 
 takes the place of the swell of the muzzle. 
 
 The face of the piece is the terminating plane per- 
 pendicular to the axis of the bore. 
 
 The trunnions are cylinders, the axes of which are 
 
116 CANNON. INTERIOR FORM. 
 
 in a plane perpendicular to the axis of the bore, both 
 axes being in the same plane. 
 
 The rimbases are short cylinders, uniting the trun- 
 nions with the body of the gun. The ends of the rim- 
 bases, or the shoulders of the trunnions, are planes per- 
 pendicular to the axis of the trunnions. 
 
 The bore of the piece includes all that part bored 
 out, viz.: the cylinder, the chamber (if there be one), 
 and the conical or spherical surface connecting them. 
 
 The muzzle, or mouth of the bore is chamfered, in 
 order to prevent abrasion and facilitate loading. 
 
 The lock-piece is a block of metal at the outer open- 
 ing of the vent for the attachment of the lock. As 
 friction-tubes are now used for firing cannon in the land 
 service, this part is omitted. 
 
 The natural line of sight is a line drawn, in a vertical 
 plane through the axis of the piece, from the highest 
 point of the base-ring to the highest point of the swell of 
 the muzzle, or to the top of the sight if there be one. 
 
 The natural angle of sight is the angle which the 
 natural line of sight makes with the axis of the piece. 
 
 The dispart is the difference of the semi-diameters 
 of the base-ring and the swell of the muzzle, or muzzle- 
 band. It is, therefore, the tangent of the natural angle 
 of sight, to a radius equal to the distance from the rear 
 of the base-ring to the highest point of the swell of the 
 muzzle, the sight, or the front of the muzzle-band, as 
 the case may be. 
 
 INTERIOR FORM. 
 
 83. Division of parts. The interior of cannon may 
 be divided into three distinct parts ; 1st, the vent, or 
 
THE VENT. . 117 
 
 channel which communicates fire to the charge ; 2d, the 
 seat of ths charge, or chamber, if its diameter be differ- 
 ent from the rest of the bore ; 3d, the cylinder, or that 
 portion of the bore passed over by the projectile. 
 
 84. The vent. The size of the vent should be as small 
 as possible, in order to diminish the escape of the gas, and 
 the erosion* of the metal which results from it. All vents 
 in -the United States' service are 0.2 inch in diameter. 
 In bronze pieces which fire large charges of powder, 
 the heat of the imiamed gases would be sufficient to 
 melt the tin, and rapidly enlarge its diameter. For this 
 reason, they are bushed by screwing in a perforated 
 piece of pure wrought copper, called the vent-piece. See 
 
 fig. 27. This arrangement al- 
 lows the vent to be renewed 
 when too much enlarged by 
 continued use, or when closed 
 with a spike. 
 
 Position. The axis of the 
 Fig. 27 vent is generally situated in 
 
 a plane passing through the axis of the piece, and 
 at right angles to the trunnions. Formerly it made 
 an angle of 80° with the axis of the piece, measured 
 from the rear, but in nearly all pieces of new model it 
 is at right angles to this line. The first, or oblique 
 direction, was given to insure the pricking of the car- 
 tridge, in case it was not rammed completely home ; the 
 perpendicular position is given to prevent the body of 
 the friction-tube from being pulled out in firing. 
 
 * It is stated that the wear, by the passage of the gas through the vent of the large 
 13-in. wrought gun lately tried in England, was so great as to require rebushing 
 after every nine rounds. Field rifle-cannon with steel vent- pieces were found to 
 require rebushing after every 350 rounds ; copper vent-pieces having been found 
 to enlarge very slightly, have been adopted for all rifle guns. 
 
118 CANNON. POSITION OF VENT. 
 
 The interior orifice of the vent is placed at a distance 
 from the bottom of the chamber eqnal to a fourth of 
 its diameter, or at the junction of the sides of the cham- 
 ber with the curve of the bottom. Experiment shows 
 that this position of the vent is more favorable to the 
 full development of the force of the charge than any 
 other along its length. 
 
 Many authors have attributed the injuries which .are 
 observed to take place about the lodgment of the pro- 
 jectile, to the position of the vent at the bottom of the 
 bore, supposing that the evolution of the elastic gases 
 begins at the upper portion of the charge, and that the 
 projectile is consequently pressed down upon the lower 
 side of the bore before it is set in motion. To remedy 
 this, it was proposed to place the orifice at the centre of 
 the bottom of the bore ; and to determine the merits of 
 this proposition, special experiments were made at the 
 artillery schools of Douai, Toulouse, and Strasbourg, on 
 new guns of 24 and 16 lbs. calibre. 
 
 The first gun had the ordinary, old-fashioned vent ; 
 see fig. 27 (A) ; in the second the orifice of the vent 
 was placed at the centre of the bottom, with its axis 
 making an angle of 30° with that of the gun (i?) ; and 
 the third had its orifice at the centre of the bottom, 
 with its axis coincident with that of the gun ( C). 
 
 The several pieces were fired under the same circum- 
 stances, and the injuries noted with great care. It was 
 found that the gun with the ordinary vent had only ex- 
 perienced slight injuries, while the others became un- 
 serviceable in a few rounds; as will be seen by an 
 examination of the following table : 
 
LOSS. 
 
 119 
 
 Position of the vent. 
 
 Depth of Lodgement. 
 
 r 
 
 Strasbourg 
 24-pdr. Gun. 
 
 Toulouse 
 24-pdr. Guns. 
 
 "'■ ^ 
 Douai 
 16-pdr. Gun. 
 
 Vent in the axisJ 
 
 Vent inclined 30<»] 
 Ordinary vent 
 
 37 points after J 
 40 shots. j 
 
 34 points after j 
 60 shots. ( 
 
 23 points after 6 sh. ( 
 25 " M 30 " -j 
 
 14£ " " 6" ( 
 33 " " 30 " ] 
 
 3 " " 30 " i 
 
 8 points aft. 6 sh. 
 17 " " 30 " 
 
 24 " " 60 " 
 14 " " 30 " 
 
 25 " « 90 " 
 
 3 " u 60 " 
 
 4 " " 90 " 
 
 The most probable explanation of these results is 
 this : In guns with the ordinary vent, the gas which is 
 developed in the first moments of combustion, expands 
 freely into the space between the top of the cartridge 
 and bore ; it has therefore less tension when it passes 
 over the ball, which will have been moved before all 
 the charge is inflamed. In the two cases in which the 
 orifice is situated at the centre of the bottom, the gas 
 formed cannot develop itself in the space over the 
 charge, but it expands into the interstices of the charge 
 with a greater tension than it had in the first case, and 
 thereby accelerates the inflammation of the charge. 
 From this it follows, that the ball is not moved from its 
 place quite so soon as in the first case, but it begins to 
 move at an epoch more nearly approximating that of 
 the maximum tension of the gas of the charge ; and the 
 pressure, therefore, of the gas as it passes over the ball, 
 will be greater ; which will account for the greater 
 depth of the lodgment. 
 
 85. L-oss. Experiment also shows that the actual loss 
 of force by the escape of gas through the vent, as com- 
 pared to that of the entire charge, is inconsiderable, 
 and may be neglected in practice. 
 
\ 
 120 CANNON. SEAT OF THE CHARGE. 
 
 SEAT OF THE CHARGE. 
 
 86. Seat of the Charge. The form of that part of the 
 bore of a fire-arm which contains the powder, will have 
 an effect on the force of the charge, and the strength of 
 the piece to resist it. 
 
 The points to be considered as most likely to affect 
 the force of the powder, are, the form of the surface, 
 and its extent compared to the enclosed volume. In 
 the first place, to obtain the full force of a charge, its 
 form should be such that its inflammation will be nearly 
 completed before the gas begins to escape through the 
 windage, and the projectile is sensibly moved from its 
 place — in other words, the length of the space occupied 
 by the charge should be nearly equal to its diameter ; 
 in the second place, as the tension depends much upon 
 the heat evolved by the combustion, the absorbing sur- 
 face should be a minimum compared to the volume. 
 
 87. Heavy charges. The charges with which solid 
 projectiles are generally fired being greater than \ of 
 their weight, the cartridge occupies a space, the length 
 of which is greater than the diameter ; in cannon, there- 
 fore, which fire solid projectiles, the form of the seat of 
 the charge is simply the bore prolonged; this arrange- 
 ment, when compared with the chamber, makes the 
 absorbing surface of the metal a minimum, and reduces 
 the length of the charge so that its inflammation will 
 be as complete as possible, before the gas escapes and 
 the projectile is moved. 
 
 To give additional strength to the breech, and to 
 prevent the angle formed by the plane of the bottom 
 
LIGHT CHARGES. 121 
 
 and sides of the bore from becoming a receptacle for 
 dirt, and burning fragments of the cartridge-bag, it is 
 rounded with the arc of a circle whose radius is one- 
 fourth the diameter of the bore at this point. See fig. 
 27. Instead of being a plane bottom, it is sometimes 
 made hemispherical, tangent to the surface of the bore. 
 In all cannon of the most recent model, the bottom of 
 the bore is a semi-ellipsoid. This is thought to fulfil 
 the condition of strength more fully than the hemi- 
 sphere. 
 
 88. L-igiit charges. When a light piece is used to 
 throw a projectile of large diameter and great weight, 
 the effect of the recoil can only be diminished by em- 
 ploying a small charge of powder. 
 
 If such a charge were made into a cartridge of a 
 form to fit the bore, its length would be less than its 
 diameter, and being ignited at the top, a considerable 
 portion of the gas generated in the first instants of in- 
 flammation, would pass through the windage, and a 
 part of the force of the charge would be lost. 
 
 To obviate this defect, to give the cartridge a more 
 manageable form in loading, and to make the surface 
 a minimum, as regards the volume, the diameter of this 
 part of the bore is reduced so as to form a chamber. 
 
 The shape of the chambers of fire-arms is either 
 cylindrical, conical, or spherical. 
 
 The effect of these different forms of chambers on 
 the velocity of the projectile will be modified by the 
 size of the charge and the length of the bore. Up to 
 a charge of powder equal to \ of the weight of the 
 projectile, and a length of bore equal to 9 or 10 calibres, 
 experience shows that the presence of a chamber is ad- 
 
122 
 
 CANNON. SEAT OF THE CHARGE. 
 
 vantageous ; but beyond these, it possesses no advan- 
 tages to compensate for its inconvenience. 
 
 Cylindrical chamber. For very small charges of pow- 
 der, and short lengths of bore, 
 the cylindrical chamber gives bet- 
 ter results than the conical cham- 
 ber. This may be explained by 
 the fact, that in this chamber the 
 charge acts a longer time on the 
 projectile, inasmuch as it acts on 
 a smaller portion of its surface, and the grains of pow- 
 der are therefore more completely consumed when the 
 projectile leaves the piece. But for larger charges the 
 conical chamber is found to answer best ; which may 
 be seen from the following table taken from actual 
 firing : 
 
 Fig. 28. 
 
 MORTARS. 
 
 CHARGE. 
 
 CYLINDRICAL CHAMBER. 
 
 CONICAL CHAMBER. 
 
 10-inch. 
 
 1.10 lbs. 
 
 456 meters. 
 
 390 meters. 
 
 u 
 
 1.65 " 
 
 790 " 
 
 695 
 
 t» 
 
 2.20 " 
 
 1060 " 
 
 969 " 
 
 a 
 
 2.75 " 
 
 1290 . " 
 
 1297 
 
 M 
 
 7.00 " 
 
 
 2530 " 
 
 u 
 
 7.90 " 
 
 2530 " 
 
 2750 " 
 
 8-inch. 
 
 0.50 " 
 
 325 " 
 
 210 
 
 u 
 
 0.60 " 
 
 775 " 
 
 540 
 
 u 
 
 1.30 " 
 
 1250 
 
 1308 " 
 
 Note. — Supposed to have been fired at 45 ° elevation. 
 
 Conical chambers. For the same capacity, the coni- 
 cal chamber gives a shorter cartridge, and is therefore 
 better suited to the rapid inflammation of a large 
 charge of powder than the cylindrical chamber. It 
 
EFFECT ON STRENGTH. 
 
 123 
 
 Fig. 29. 
 
 also presents less surface of, 
 metal for the absorption of 
 heat. The particular kind of 
 chamber represented in the di- 
 agram is called a Gomer cham- 
 ber, after its inventor. Its prin- 
 cipal advantages are, that of distributing the force of 
 the charge over a large portion of the surface of the 
 projectile, thereby rendering it less liable to break, if it 
 be hollow; and that of destroying the windage when 
 the projectile is driven down to its proper place. 
 
 Spherical chamber. This chamber was formerly used 
 in mortars, but, owing to the inconveniences which 
 attend its construction and use, and its liability to 
 deterioration, it is now entirely 
 abandoned. Experiment shows 
 that when a chamber of this 
 kind is entirely filled with pow- 
 der, it gives a greater initial ve- 
 locity to the projectile than any 
 other ; and this, probably, for the reasons that its form 
 is better suited to the rapid inflammation of the charge ; 
 that it has the least surface compared to its capacity ; 
 that sensible motion does not take place so soon; and 
 that the escape of gas by windage is comparatively 
 small. 
 
 Other forms of chambers, such as the parabolical, 
 hyperbolical, <fec, have been proposed, but experiment 
 has failed to show that they possess any advantages 
 over other and more simple forms. 
 
 89. Effect on strength. No very careful experiments 
 have been made to determine, in a general way, the 
 
 Fig. 30. 
 
124 CANNON. WINDAGE. 
 
 effect of the chamber on the strength of cannon ; but 
 late experience indicates that cylindrical chambers in 
 heavy iron guns, have an injurious effect on their en- 
 durance, and they have consequently been abandoned 
 in these pieces. / 
 
 WINDAGE. 
 
 90. Definition. Windage is the space left between 
 the bore of a piece and its projectile, and is measured 
 by the difference of their diameters. The objects of 
 windage are to facilitate loading, and to diminish the 
 danger of bursting the piece ; it is rendered necessary 
 by the mechanical impossibility of making every pro- 
 jectile of the proper size and shape, by the unyielding 
 nature of the material of which large projectiles are 
 made, by the foulness which collects in the bore after 
 each discharge, and by the use of hot and strapped 
 shot. 
 
 The true windage, which is the difference between 
 the true diameters of the bore and projectile, increases 
 slightly with the size of the bore, and is greater for 
 solid shot, which are sometimes fired hot, than for 
 hollow projectiles, which are never heated. 
 
 91. L.©§s of force. The ordinary windage of smooth- 
 bored cannon, used in the United States' service, is 
 about T V of the diameter of the bore, and the loss of 
 force arising from the escape of gas through this wind- 
 age amounts to a very considerable portion of the 
 entire charge. 
 
 The amount of loss in any case depends on 
 
WINDAGE. 
 
 125 
 
 1. The degree of windage ; 
 
 2. The calibre of the gun ; 
 
 3. The length of the bore ; 
 
 4. The kind of powder ; 
 
 5. The charge of powder ; 
 
 6. The weight, or density of the ball. 
 
 It is probable that the influence which some of these 
 causes exert on the force of the charge is very slight ; 
 and that to determine the exact influence of each of 
 the others would be a very difficult if not an imprac- 
 ticable problem. 
 
 The most important question is, to determine what 
 allowance must be made for a given difference of ordi- 
 nary windage. 
 
 The pressure, or force, exerted by a charge of powder 
 on different balls at the same point of the bore of a 
 piece, will be proportioned to the surfaces, or squares 
 of their diameters. If the weight of the balls be the 
 same, the pressure will be proportional to the square 
 of the velocity communicated to the balls in a given 
 time. We, therefore, have the proportion — 
 
 D* 
 
 d 2 : 
 
 : V s : v 2 
 
 and D 2 
 
 d' 2 : 
 
 : V s : v 2 
 
 or D 
 
 d : 
 
 : V : v 
 
 and D 
 
 d' : 
 
 : V : »' 
 
 hese last two proportions we have 
 
 D : D-d : : V : V-v 
 
 D : D-d':: V: V-v' 
 
 or D—d : 
 
 D-d 
 
 ' :: V--v : V—v' 
 
 In which, D, d, and d' represent the diameters of three 
 balls, and F", v y v r their initial velocities, respectively. 
 If D equal the diameter of the bore, D— d is the wind- 
 
126 CANNON. WINDAGE. 
 
 age of the ball whose diameter is d, and D—d' is the 
 windage of the ball whose diameter is d'. If we mul- 
 tiply the extremes and means of the last proportion, and 
 divide the resulting equation by V (D— d), we shall 
 have the expression 
 
 v-v' /n , N v-v 
 
 - T -= { D-d) irw - T y 
 
 V—v 
 
 By making m= „,^ , 1 the equation becomes 
 
 V- V '=Vxm(D-d'). 
 
 This equation expresses the relation between a certain 
 windage, D— aT and the loss of velocity due to that 
 windage, or V—v'. 
 
 In a series of experiments made by Major Mordecai, 
 with the ballistic and gun pendulums, it was found that 
 m was constant for all values of D—d' that would be 
 likely to arise in service. From this it follows that V 
 —v' is proportional to D—d '; or, in other words, that 
 the loss of velocity by windage is proportional to the 
 windage. 
 
 When the charge of powder was varied, it was found 
 that the absolute loss of velocity by a given increase of 
 windage, was very nearly the same for all the charges 
 used. It follows from this tlmt the proportional loss is 
 less for the higher charges. 
 
 Both the absolute and relative loss of velocity by a 
 given difference of windage (say one-tenth of an inch) 
 increase as the calibre of the piece decreases. 
 
 From the foregoing, it may be stated, that the loss of 
 velocity by a given windage, is directly as the windage, 
 and inversely as the diameter of the bore, very nearly. 
 
LENGTH OF BORE. 127 
 
 The loss of velocity of a 24-pdr. ball by a windage 
 of ^-, and a charge of 6 lbs. of powder, is 9 per cent. 
 
 LENGTH OF BORE. 
 
 92. Ancient theory. The slow rate of burning of 
 mealed powder, which was originally used in cannon, 
 led to the belief that the longest pieces gave the great- 
 est ranges. In spite of much experience to the con- 
 trary, this belief was entertained, even after gunpowder 
 received its granular form ; and several pieces were 
 made of enormous length, with the expectation of real- 
 izing corresponding ranges. s 
 
 A culverin was cast during the reign of Charles V. 
 which was 58 calibres long, and fired a ball weighing 
 36 lbs.; but on trial, this piece was found to have 
 actually less range than an ordinary 12-pdr. gun. 
 
 The experiment of reducing its length, by successively 
 cutting it off to 50, 44, and 43 calibres, was tried, and 
 it was found that the range increased at each reduction 
 until it gained 2,000 paces. 
 
 93. What governs the length. That the length of the 
 bore has an important effect on the velocity of the 
 projectile, will be readily seen by a consideration of 
 the forces which accelerate and retard its movement in 
 the piece. 
 
 The accelerating force is due to the expansive effort 
 of the inflamed powder, which reaches its maximum 
 when the grains of the charge are completely converted 
 into vapor and gas. This event depends on the size 
 of the charge, and the size and velocity of combustion 
 of the grains. With the same accelerating force, the 
 
128 CANNON. LENGTH OF BORE. 
 
 point at which a projectile reaches its maximum velocity- 
 depends on its density, or the time necessary to over- 
 come its inertia. 
 
 The retarding forces are — 1st. The friction of the 
 projectile against the sides of the bore : this is the 
 same for all velocities, but different for different metals; 
 2d. The shocks of the projectile striking against the 
 sides of the bore : these will vary with the angle of in- 
 cidence, which depends on the windage, and the extent 
 of the injury due to the lodgment and balloting of the 
 projectile ; 3d. The resistance offered by the column of 
 air in front of the projectile : this force will increase in 
 a certain ratio to the velocity of the projectile and 
 length of the bore. 
 
 As the accelerating force of the charge increases up 
 to a certain point, after which it rapidly diminishes, as 
 the space in rear of the projectile increases, and as the 
 retarding forces are constantly opposed to its motion, it 
 follows, that there is a point where these forces are 
 equal and the projectile moves with its greatest velocity ; 
 it also follows that after the projectile passes this point, 
 its velocity decreases until it is finally brought to a state 
 of rest, which would be the case in a gun of great length. 
 
 94. Experiments to determine it. Elaborate experi- 
 ments have been made in this country and abroad, to 
 determine accurately the influence which the length of 
 the piece exercises on the velocity of its projectile. 
 
 The curves in the accompanying figure show to the 
 eye the relation existing between the different lengths 
 of the bore of a 12-pdr. gun and the corresponding 
 velocities, for charges of 2.2, 3.3, and 4.4 lbs. 
 
 The ordinates represent the lengths of the bore in 
 
CONCLUSIONS. 
 
 129 
 
 calibres, and the abscissas represent the velocities, as 
 determined by the electro-ballistic pendulum. 
 
 Length in calibres 
 ii 
 
 M 
 
 (( 
 (( 
 II 
 
 20.8 
 18.3 
 15.8 
 13.3 
 10.8 
 8.3 
 5.8 
 
 V 
 
 e 
 
 1 
 
 o 
 
 cities 
 
 1 
 
 
 
 
 
 22 lbs. 3- Jibs. 
 
 A-UIbs. 
 
 _J | 
 
 / / 
 
 / / / 1 
 
 / / y 1 
 
 s / / 
 
 
 
 
 
 s^^^ 
 
 1 
 
 Pig. 31. 
 
 An inspection of the figure shows that the velocity 
 increases with the length of the bore in a variable ratio, 
 the increase of velocity for the short lengths being much 
 greater than for the long lengths. 
 
 The experiments made by Major Mordecai, some years 
 before these, on a gun of the same calibre, show that 
 the velocity increases with the length of the bore up to 
 25 calibres ; but that the entire gain beyond 16 calibres, 
 or an addition of more than one half to the length of the 
 gun, gives an increase of only one -eighteenth to the effect 
 of a charge of 4 lbs. 
 
 95. Conclusions. It follows from the foregoing, that 
 the length of bore which corresponds to a maximum 
 velocity, depends upon the projectile, charge of powder, 
 and material of which the piece is made ; and taking 
 the calibre as the unit of measure, it is found that this 
 length is greater for small arms, which fire leaden pro- 
 jectiles, than for guns which fire solid iron shot, and 
 greater for guns than for howitzers and mortars, which 
 
 fire hollow projectiles. 
 9 
 
130 CANNON. CHAEGE. 
 
 For the same charge of powder, it may be said that 
 the initial velocity of a projectile varies, nearly, with the 
 fourth root of the length of the bore, provided the varia- 
 tion in length be small. 
 
 CHARGE. 
 
 96. Maximum charge. By increasing the charge of 
 powder of a fire-arm, the greater and (in consequence 
 of the wedging of the unburned grains among each 
 other) the more difficult will be the mass to be set in 
 motion ; the space between the front of the charge and 
 the muzzle will be diminished ; and a larger number of 
 grains will be thrown out unconsumed. It is evident, 
 therefore, that the effect of a charge of powder on a 
 projectile should not increase with the size of the 
 charge; and experiment shows that beyond a certain 
 point, an increase of charge is actually accompanied 
 with a loss of velocity. The charge corresponding to 
 this point is called the maximum charge. 
 
 The following are the results of experiments made 
 in France on a 36-pounder gun, of 16 calibres in length : 
 
 Charge, lbs., . . 36, 42, 49, 56, 70, 77. 
 
 Initial velocity, feet, 1,320, 1,170, 950, 493, 454, 191. 
 
 It will therefore be seen that an excess of charge is 
 almost as injurious to the velocity of a projectile, as an 
 excess of length of bore. 
 
 97. Effect§ on recoil. Trials made at Turin show that 
 the recoil, and consequently the strain on the gun and 
 carriage, increase in a more rapid ratio than the charges, 
 
MATERIALS. 131 
 
 viz.: 14 lbs. of powder gave a recoil of 70 inches; 15 
 lbs., 72 inches; 16 lbs., 74 inches; 18 lbs., 100 inches. 
 
 98. Effect of length of bore on maximum charge. All 
 
 experience proves that the longer a piece is, in terms of 
 its calibre, the greater will be the maximum charge in 
 proportion to the weight of the projectile. For heavy 
 cannon, 19 to 20 calibres long, the maximum charge may 
 be stated to be £ the weight of the projectile ; and for 
 light cannon of the same length, \ to -§- of this weight ; 
 the increase of range for charges above \ the weight 
 of the projectile, being very small. 
 
 99. Most §uitabie charge. A charge of \ the weight 
 of the projectile, and a bore of 18 calibres, is the most 
 favorable combination that can be made in smooth- 
 bored cannon, to obtain the greatest range with the 
 least strain to the carriage. 
 
 In the early days of artillery, when dust instead of 
 grained powder was used in cannon, the weight of 
 the charge was equal to that of the projectile ; after 
 the introduction of grained powder, it was reduced 
 to |, and in 1740 to £, this weight. 
 
 MATERIALS. 
 
 100. Requirements. Before discussing the exterior 
 form of cannon, it is necessary to study the nature 
 of the materials of which they are composed. The 
 selection of a suitable material is a very important 
 consideration in the construction of cannon, in conse- 
 quence of the great difficulty of obtaining any one 
 that possesses all the qualities required of it. 
 
132 CANNON. MATEEIALS. 
 
 The qualities necessary in cannon-metals are, strength 
 to resist the explosion of the charge, weight to overcome 
 severe recoil, and hardness to endure the bounding of 
 the projectile along the bore. 
 
 101. strength. The term strength, as applied to a 
 cannon-metal, should not be confined to tensile strength 
 alone, which expresses the ability of a substance to 
 resist rupture from extension produced by a simple 
 pressure, as a weight, but should embrace a knowledge 
 of its elasticity, ductility, and crystalline structure, which 
 affect its power to resist the enormous and oft-repeated 
 force of gunpowder — a force which resembles a blow, 
 in the rapidity of its application. 
 
 Elasticity. It has been shown by experiment, that 
 the feeblest strains produce permanent elongation or 
 compression in iron ; and the same is probably true of 
 all other materials. Perfect elasticity cannot, there- 
 fore, be found in solids, although different substances 
 possess it in different degrees. It follows that each 
 discharge, however small, must impair the strength of 
 a cannon, and an ordinary discharge, repeated a suf- 
 ficient number of times, will burst it. 
 
 In the selection of a durable cannon-metal, it is 
 necessary to know, not only the ultimate rupturing 
 force, but also the relation between lesser forces, and 
 the extension and compression produced by them, and 
 the permanent extension, or compression, which remains 
 after these forces are withdrawn, or what is technically 
 known as the " permanent set." This knowledge will 
 be useful in regulating the charge of a cannon to suit 
 the required endurance. 
 
 Ductility. Ductility is the property which a metal 
 
MATERIALS. 133 
 
 possesses of changing its form, without rupture, after it 
 has passed its elastic limit, under the operation of ex- 
 traneous forces, and, for present purposes, may be con- 
 sidered as opposed to brittleness. « 
 
 Of two metals that possess the same tensile strength 
 and elasticity, it is evident that it will require more 
 " work" to rupture the one which possesses the greatest 
 amount of ductility. 
 
 Crystalline structure. The size and arrangement of 
 the crystals of a metal, have an important influence on 
 its strength to resist a particular force. This arises from 
 the fact that the adhesion of the crystals, by the contact 
 of their faces, is less than the cohesion of the particles 
 of the crystals themselves, and that, consequently, rup- 
 ture takes place along the larger, or principal crystalline 
 faces. 
 
 A metal will be strongest, therefore, when its crystals 
 are small, and the principal faces are parallel to the 
 straining force, if it be one of extension, and perpen- 
 dicular to it, if it be one of compression. 
 
 The size of the crystals of a particular metal depends 
 on the rate of cooling of the heated mass : the most 
 rapid cooling gives the smallest crystals. Practically, 
 there is a limit to the rate of cooling of certain metals ; 
 cast iron, for instance, is supposed to change its nature 
 by losing a portion of its uncombined carbon, when 
 suddenly cooled, as in iron moulds. 
 
 The position of the principal crystalline faces of a 
 cooling solid, is found to be parallel to the direction in 
 which the heat leaves it, or in a direction perpendicular 
 to the cooling surface. 
 
 The result of this arrangement of crystals is to create 
 
134 CANNON. MATERIALS. 
 
 planes of weakness where the different systems of crys- 
 tals intersect. Figure 32 represents sections of the 
 cylinders of two hydraulic presses, used in the construc- 
 tion of the Britannia Bridge. The bottom of No. 2, 
 which was flat, gave way along the lines of weakness 
 
 A B and C D, while 
 No 1, which was hemi- 
 spherical, and present- 
 ed no lines of weak- 
 ness, resisted all the 
 Fi £- 32 - pressure applied to it. 
 
 The effect of this law on the strength of cannon seems 
 to have been first noticed by Mr. Mallet ; and its truth 
 has been confirmed in several instances by Captain Rod- 
 man, of the ordnance department, who finds that radial 
 specimens are more tenacious than those cut tangentially 
 from the same gun. 
 
 102. Effect of cooling. All solid bodies contract their 
 size in the operation of cooling. It follows, therefore, 
 that if the different parts of a body cool unequally, they 
 will contract unequally, and the body will change its 
 form, provided it be not restrained by the presence of a 
 superior force ; if it be so restrained, the contractile force 
 will diminish the adhesion of the parts by an amount 
 which depends on the rate of cooling of the different 
 parts, and the contractibility of the metal. 
 
 This is an important consideration in estimating the 
 strength and endurance of cannon, particularly those 
 made of cast iron, as will be seen by examining the form 
 of the casting and the method of cooling it. 
 
 The general form of the casting is that of a solid frus- 
 tum of a cone ; it is, therefore, cooled from the exterior, 
 
EFFECT OF COOLING. 135 
 
 which causes the thin outer layer to contract first, and 
 force the hotter and more yielding metal within, toward 
 the opening of the mould. Following this, the adjacent 
 layer cools, and tends to contract ; but the exterior layer, 
 to which it coheres, has become partially rigid, and does 
 not fully yield to the contraction of the inner layer. 
 The result is, the cohesion of the particles of the inner 
 layer is diminished by a force of extension, and that of 
 the outer layer increased by a force of compression. 
 
 As the cooling continues, this operation is repeated 
 until the whole mass is brought to a uniform tempera- 
 ture ; and the straining force is increased to an extent 
 which depends on the size and form of the mass, the 
 rapidity with which it is cooled, and the contractibility 
 of the particular metal used. 
 
 All cannon, therefore, that are cooled from the exte- 
 rior are affected by two straining forces — the outer por- 
 tion of the metal being compressed, and the interior 
 extended, in proportion to their distances from the neu- 
 tral axis, or line composed of particles which are neither 
 extended nor compressed by the cooling process. 
 
 The effect of this unequal contraction may be so great 
 as to crack the interior metal of cast-iron cannon, even 
 before it has been subjected to the force of gunpowder; 
 and chilled rollers, which are cooled very rapidly by 
 casting them in iron moulds, have been known to split 
 open longitudinally, from no other cause than the enor- 
 mous strains to which they are thus subjected. 
 
 The strain produced by the action of a central force, 
 as gunpowder acting in a cannon, is not distributed 
 equally over the thickness of metal. Barlow shows 
 that it diminishes as the square of the distance from the 
 
136 CANNON. MATERIALS. 
 
 centre increases* It follows from this, that the sides of 
 a cannon are not rent asnnder as by a simple tensile 
 force, but they are torn apart like a piece of cloth, com- 
 mencing at the surface of the bore. This is confirmed 
 by experience; for the inner portion of the fractured 
 surface of a ruptured gun, is found to be stained with 
 the smoke of the powder, while the outer portion is un- 
 touched by it. 
 
 It will thus be seen that the effect of ordinary cooling 
 is, to diminish the strength and hardness of the metal of 
 cannon at, or near, a point where the greatest strength 
 and hardness are required, i. e. y at the surface of the 
 bore. 
 
 Circumstances affecting it. The strains produced by 
 unequal cooling increase with the diameter of the cast- 
 ing, and the irregularity of its form. This explains the 
 great difficulty which is found in making large cast-iron 
 cannon proportionally as strong as small ones ; and also, 
 how it is that projections, like bands, mouldings, &c, 
 injure the strength of cannon. It also explains why 
 cannon made of " high?' 1 cast iron, or cast iron made more 
 tenacious by partial decarbonization, are not so strong 
 as cannon made of weaker iron ; for it is well known 
 that such iron contracts more than the latter in cooling, 
 and therefore produces a greater strain of extension on 
 the surface of the bore. 
 
 Rodmarfs plan. The foregoing considerations led 
 Captain Kodman to propose a plan for cooling cannon 
 from the interior, hoping thereby to reverse the strains 
 
 * From this law it can be shown that a piece with a thickness of metal equal to 
 one calibre, experiences nine times greater strain on the surface of the bore than on 
 the exterior. 
 
WEIGHT, HARDNESS, ETC. 137 
 
 produced by external cooling, and make them con- 
 tribute to the endurance rather than to the injury of 
 the piece. 
 
 The method employed is, to carry off the internal 
 heat by passing a stream of water through a hollow 
 core, inserted in the centre of the mould-cavity before 
 casting, and to surround the flask with a mass of 
 burning coals to prevent too rapid radiation from the 
 exterior. 
 
 Extensive trials have been made to test the merits of 
 this plan ; and the results show that cast-iron cannon 
 made by it are not only stronger but are less liable to 
 enlargement of the bore from continued firing. 
 
 Indications were shown, however, in these and in 
 other trials, that the strains produced by unequal cool- 
 ing are modified by time, which probably allows the 
 particles to accommodate themselves, to a certain extent, 
 to their constrained position, as in the case of a bent 
 spring or hoop. 
 
 103. Weight. When a material possesses great strength, 
 but cannot be easily wrought into a heavy mass, it is 
 customary to diminish the recoil by applying an ex- 
 traneous weight to the piece, or by some contrivance 
 for increasing the weight or friction of the carriage. 
 It is evident that these methods want that unity and 
 solidity which are necessary to great endurance in can- 
 non. 
 
 104. Hardness. Without a certain degree of hardness, 
 the shape of the bore will be rapidly altered by the ac- 
 tion of the projectile, and the accuracy and safety of the 
 piece will be destroyed. 
 
 In rifle cannon, hardness is particularly necessary, to 
 
138 CANNON. MATERIALS. 
 
 enable the spiral grooves to resist this action ; at least, 
 the surface of the bore should be relatively harder than 
 the projectile. 
 
 105. Corrosion, &c Cannon metals should be able to 
 resist the corroding action of the atmosphere, and the 
 heat and the products of combustion of the powder; 
 should be susceptible of being easily bored and turned ; 
 and should not be too costly, on account of the great 
 number and weight of cannon required for the military 
 service. 
 
 106. Kind of Metai§. The principal materials hereto- 
 fore used, in the fabrication of cannon, are bronze, steel, 
 wrought iron, and cast iron, each of which possesses its 
 peculiar advantages and disadvantages. 
 
 107. Bronze. Bronze for cannon (commonly called 
 brass), consists of 90 parts of copper and 10 of tin, al- 
 lowing a variation of one part of tin, more or less. By 
 increasing the proportion of tin, bronze becomes harder, 
 but more brittle and fusible ; by diminishing it, it be- 
 comes too soft for cannon, and at the same time loses a 
 part of its elasticity. Bronze is more fusible than cop- 
 per, much less so than tin, more sonorous, harder, and 
 less susceptible of oxidation, and much less ductile than 
 either of its constituents. Its fracture is of a yellowish 
 color, with little lustre, a coarse grain, irregular, and often 
 exhibiting spots of tin, which are of a whitish color. 
 These spots indicate defects of metal, which are sup- 
 posed to arise from a disposition of the ingredients to 
 separate, in the melted state, into two distinct alloys, or 
 chemical compounds, possessing different degrees of fus- 
 ibility. The amount of tin which the lighter-colored 
 alloy contains, never exceeds 25 per cent. 
 
KIND OF METALS. STEEL. 
 
 139 
 
 Properties. The density and tenacity of bronze, when 
 cast into the form of cannon, are found to depend npon 
 the pressure and mode of cooling. This is exhibited 
 by the mean of observations made on five guns cast at 
 the Chickopee Foundry, viz. : 
 
 Density. 
 
 Tenacity per square inch. 
 
 Breech-square. 
 
 Gun-head. 
 
 Finished Gun. 
 
 Breech-square. 
 
 Gun-head. 
 
 1 8.765 
 
 8.444 8.740 
 
 46.509 lbs. 
 
 27.415 
 
 The guns were cast in a vertical position, with the 
 breech-square at the bottom. 
 
 In consequence of the difference of fusibility of tin 
 and copper, the perfection of the alloy depends much 
 on the nature of the furnace, and the treatment of the 
 melted metal. By these means alone, the tenacity of 
 bronze has been lately carried, at the Washington Navy- 
 Yard Foundry, as high as 60,000 lbs. 
 
 Bronze is but slightly corroded by the action of the 
 gases evolved from gunpowder, or by atmospheric 
 causes; but its tin is liable to be melted away at the 
 sharp corners by the great heat generated by rapid 
 iiring. It is soft, and therefore liable to serious injury 
 by the bounding of the projectile in the bore: this 
 injury is augmented, as the force of the rebound is 
 increased by the elasticity of the metal. The price of 
 
 f bronze cannon is about 45 cents per pound. 
 108. steel. This substance possesses, in a higher de- 
 ^gree than any other, the important qualities of tenacity 
 and hardness; but the practical difficulty of making it 
 
140 CANNON. STEEL. 
 
 in masses of sufficient size, has heretofore prevented it 
 from being used in the construction of heavy cannon. 
 
 Steel is a compound of iron and carbon, in which the 
 proportion of the latter is from 5 to 1 per cent., and 
 even less, in some kinds. Steel may be distinguished 
 from iron by its fine grain ; its susceptibility of harden- 
 ing by immersing it, when hot, in cold water ; and with 
 certainty by the action of diluted nitric acid, which 
 leaves a black spot on steel, and on iron a spot which is 
 lighter colored in proportion as the iron contains less 
 carbon. 
 
 There are many varieties of steel, the principal of 
 which are : 
 
 Natural steel, which is obtained by reducing the rich 
 and pure kinds of iron ore with charcoal, and refining 
 the cast iron, so as to deprive it of a sufficient portion of 
 carbon to bring it to a malleable state. It is made 
 principally in Germany, and is used for making files 
 and other tools. 
 
 The India steel, called wootz, is said to be a natural 
 steel, containing a small portion of other metals. 
 
 Blistered steel, or steel of cementation, is prepared by 
 the direct combination of iron and carbon. For this 
 purpose, the iron in bars is put in layers alternating 
 with powdered charcoal, in a close furnace, and exposed 
 for seven or eight days to a heat of about 10° Wedge- 
 wood, and then sufikred to cool for as many days more. 
 The bars, on being taken out, are covered with blisters, 
 have acquired a brittle quality, and exhibit in the frac- 
 ture a uniform crystalline appearance. The degree of 
 carbonization is varied according to the purposes for 
 which the steel is intended, and the best qualities of 
 
KIND OF METALS. STEEL. 141 
 
 iron (Russian and Swedish) are used for the finest kinds 
 of steel. 
 
 Tilted steel is made from blistered steel moderately 
 heated and subjected to the action of a tilt-hammer, by 
 which means its tenacity and density are increased, and 
 it is thus adapted to use. 
 
 Shear steel is made from blistered or natural steel re- 
 fined by piling thin bars into fagots, which are brought 
 to a welding heat in a reverberatory furnace, and ham- 
 mered or rolled again into bars. This operation is 
 repeated several times to produce the finest kinds of 
 shear steel, which are distinguished by the names of 
 half shear, single shear, and double shear, or steel of 1 
 mark, of 2 marks, of 3 marks, &c, according to the 
 number of times it has been piled. 
 
 Cast steel is made by breaking blistered steel into 
 small pieces and melting it in close crucibles, from which 
 it is poured into iron moulds ; the ingot is then reduced 
 to a bar by hammering or rolling, as described under 
 the head of malleable iron, these operations being per- 
 formed with great care. Cast steel is the finest kind of 
 steel, and best adapted for most purposes : it is known 
 by a very fine, even, and close grain, and a silvery, homo- 
 geneous fracture ; it is very brittle, and acquires extreme 
 hardness, but it is difficult to weld without the use of a 
 flux. The other kinds of steel have a similar appear- 
 ance to cast steel, but the grain is coarser and less ho- 
 mogeneous ; they are softer and less brittle, and weld 
 more readily. A fibrous or lamellar appearance in the 
 fracture indicates an imperfect steel. A material of 
 great toughness and elasticity, as well as hardness, is 
 made by forging together steel and iron, forming the 
 
142 CANNON. STEEL. 
 
 celebrated damask-steel, which is used for sword-blades, 
 springs, etc. ; the damasked appearance is produced by 
 the action of a diluted acid, which gives a black tint to 
 the steel parts, whilst the iron remains white. 
 
 Various fancy steels, or alloys of steel with silver, 
 platinum, rhodium, and aluminum, have been made 
 with a view to imitating the Damascus steel, wootz, 
 etc., and improving the fabrication of some of the finer 
 kinds of surgical and other instruments. 
 
 Properties of steel. The best steel possesses the fol- 
 lowing characteristics : heated to redness and plunged 
 into cold water, it becomes hard enough to scratch glass 
 and to resist the best files ; the hardness is uniform 
 throughout the piece; after being tempered it is not 
 easily broken; it welds readily; it does not crack or 
 split ; it bears a very high heat, and preserves the capa- 
 bility of hardening after repeated working ; the grain 
 is fine, even, and homogeneous, and it receives a bril- 
 liant polish. Its specific gravity is 7.816, being greater 
 than that of iron. 
 
 109. Puddled §teei. If, in the operation of puddling, 
 or decarbonizing cast iron, the process be stopped at a 
 particular time, determined by indications given by the 
 metal to an experienced eye, an iron is obtained of 
 greater hardness and strength than ordinary iron, to 
 which the name of semi-steel, or puddled steel, has been 
 applied. The principal difficulty in its manufacture is 
 that of obtaining uniformity in the product, homogeneity 
 and solidity throughout the entire mass. It is much 
 improved by reheating and hammering under a heavy 
 hammer. 
 
 A tenacity of 118,000 lbs. to the square inch has been 
 
KIND OF METALS. WROUGHT IRON. 143 
 
 obtained from semi-steel made in this country in this 
 way. Field-pieces have been made of this material, but, 
 thus far, they have not been found to possess uniform 
 strength and endurance. 
 
 110. Wrought iron. This material was- among the 
 earliest employed in the construction of cannon ; but, in 
 consequence of the defects which almost invariably ac- 
 company the forging of large masses, it was superseded 
 by bronze and cast iron. Notwithstanding that most 
 authorities unite in stating that this change was con- 
 sidered, at the time, a great improvement, frequent at- 
 tempts have been made to revive the use of wrought 
 iron, and especially within the last two years, but with- 
 out success. 
 
 Tensile strength. The tensile strength of wrought 
 iron, which, under the most favorable circumstances, is 
 double that of the best cast iron, depends on the charac- 
 ter of the crystalline structure, and the manner of ap- 
 plying the tensile force ; or, in other words, wrought 
 iron offers the greatest resistance to a force of extension, 
 when the structure is fibrous and the force acts in the 
 direction of the fibres. From experiments made to de- 
 termine the elastic limits, and tensile strength with 
 reference to the direction of the fibre, Mallet makes this 
 important deduction : that for artillery purposes, the 
 ultimate strength of a fire-arm in which the explosive 
 strains are all resisted by wrought iron in the direction 
 of the fibre, is to the resistance in a transverse direction 
 as 234.80 is to 30.47, or H to 1. 
 
 But the practical difficulties of rapidly cooling large 
 masses, so as to form small crystals, and compressing 
 them by hammering, rolling, or otherwise, to develop 
 
144 CANNON. MATERIALS. 
 
 and give a particular direction to the fibre, have not 
 thus far been wholly surmounted by the most liberal 
 expenditure of money and mechanical skill.* On the 
 contrary, large masses are generally found to contain 
 such internal defects as false welds, cracks, and a spongy 
 and irregularly crystalline structure, arising from the 
 more rapid cooling of the exterior surface. 
 
 From careful trials made with the material of the 
 large wrought-iron gun which burst with such fatal 
 results on the steamer Princeton a few years ago, it 
 was ascertained that it had lost one-sixth of its original 
 strength in the process of manufacture, and the texture 
 of the fragments varied from fine granular to coarse 
 crystalline. 
 
 Hardness, &c. Wrought iron is softer than cast iron, 
 and being pure iron, is more liable to be corroded by 
 the action of the atmosphere, and products of combus- 
 tion of the powder. 
 
 Ductility. It possesses considerable ductility, or 
 extension beyond the elastic limit, as was shown by 
 experiments made on the iron used in the Prince- 
 ton's gun. A bar 0.6 inch diameter was stretched so 
 much that its diameter was reduced to 0.5 before rup- 
 ture. 
 
 111. Ca§t iron. This metal is now very generally 
 employed in the fabrication of heavy cannon for siege 
 and sea-coast purposes. It possesses the very important 
 
 * Wrought-iron cannon for field service are now being successfully made by the 
 Phoenix Iron Company, near Philadelphia. Briefly, the process consists in forming 
 a bundle of iron bars in such manner that the heat may permeate the mass, and 
 bring the different parts to the welding point at the same time, and then passing 
 it through grooved rollers until it is thoroughly welded. To give a proper direction 
 to the fibre, the inner bars are placed in a longitudinal direction, and the outer ones 
 are wrapped in a spiral direction around them. 
 
CAUSES WHICH AFFECT ITS QUALITY. TESTING. 145 
 
 qualities of tenacity, hardness, and cheapness, and with 
 proper care is not seriously affected by rust. Its prin- 
 cipal defect is an almost entire want of elasticity, in 
 consequence of which its tenacity is destroyed after a 
 certain number of applications of the straining force, 
 depending on the relation which this force bears to the 
 tensile strength of the iron itself. 
 
 Causes which affect its quality. Cast iron is a well 
 known compound of iron and carbon. The amount of 
 carbon, the state of its combination, together with the 
 ore, fuel, and fluxes, and the process of manufacture, 
 materially affect the quality of cast iron for artillery 
 purposes. 
 
 Many experiments have been made by the ordnance 
 department in the last few years, to ascertain, by chem- 
 ical and mechanical means, the precise causes which im- 
 prove or injure the quality of cast iron ; but with little 
 success. The utmost that has been accomplished, is the 
 knowledge that certain ores, treated in a certain way, 
 make cast iron suitable for cannon ; but the reasons for 
 such results are but little understood. 
 
 A slight variation in the ore — even when taken from 
 the same deposit — in the fuel, in the model of the piece, 
 or in the character of the powder, has been known to 
 produce the most disastrous results. 
 
 How tested. The fitness of a particular kind of cast 
 iron for cannon-metal, can only be determined by sub- 
 mitting it to the tests of the service ; after this is known, 
 a knowledge of certain physical properties, such as 
 tenacity, hardness, density, and color, form and size of 
 
 crystals, presented in a freshly-fractured surface, will be 
 10 
 
146 CANNON. M ATERI ALS. 
 
 useful in keeping the metal up to the required standard, 
 and securing its presence in the finished piece. 
 
 The course, recently adopted in both land and naval 
 services, is to leave the selection of the metal to the 
 private founders, and to require that one gun out of a 
 certain number shall be selected, and proved in the 
 ordinary way, and afterward fired continuously 1,000 
 service-rounds. If the result be satisfactory, it is re- 
 quired that all other guns shall be made precisely like 
 it ; and it is made the duty of officers on foundry ser- 
 vice, to see that this condition is strictly complied with. 
 
 Ores. Pig, or cast iron, is generally known by the 
 name of the blast-furnace in which it is made. The 
 ores at ^present used by the U. S. government for the 
 manufacture of cannon, are the Cloverdale in Virginia, 
 Bloomfield in Pennsylvania, and the Greenwood, near 
 West Point, N. Y. Many other ores have been tried, 
 but none have thus far been found to answer so well as 
 these. /<•<{- ^~*~? A\*** t fl^g^ 
 
 Character of pig-iron. Ores suitable for " gun-metaV 
 should be reduced in the smelting furnace, with char- 
 coal and the warm blast* Iron thus made, or pig-iron 
 should be soft, yielding easily to the file and chisel ; the 
 appearance of the fracture should be uniform, with a 
 brilliant aspect, dark gray color, and medium-sized 
 crystals. 
 
 Character of gun metal. When remelted and cast into 
 cannon, it should approach that degree of hardness 
 which resists the file and chisel, but not so hard as to be 
 bored and turned with much difficulty. Its color should 
 be a bright, lively gray ; crystals small, with acute an- 
 
 * Varying from 125° to 300°, Fahr., depending upon the ore used. 
 
GENERAL PROPERTIES OF CAST IRON. 147 
 
 gles, and sharp to the touch ; structure uniform, close, 
 and compact. 
 
 If pig-iron be too soft, coarse, and loose, its strength 
 and density may be increased by remelting it once or 
 twice, and by allowing it to remain in a state of fusion, 
 subjected to a high degree of heat. 
 
 The density of pig-iron is about 7.00 and its tenacity 
 about 16.000 pounds to the square inch. The density 
 of gun-metal, or remelted pig, is about 7.250, and its 
 tenacity about 30.000 — nearly double the former. 
 
 General properties of cast iron. There are several 
 varieties of cast iron, differing from each other by al- 
 most insensible shades ; the principal divisions are gray 
 and white, called so from the color of the fracture when 
 recent. 
 
 Gray iron is softer and less brittle than white iron ; 
 it is in a slight degree malleable and flexible ; and is 
 not sonorous ; it can be easily drilled and turned in the 
 lathe, and does not resist the file. It has a brilliant 
 fracture, of a gray, or sometimes bluish-gray color ; the 
 color is lighter as the grain becomes closer, and its hard- 
 ness increases at the same time. A medium-sized grain, 
 bright-gray color, lively aspect, fracture sharp to the 
 touch, and close, compact texture, indicate a good quali- 
 ty of iron. A grain either very large or very small, a 
 dull, earthy aspect, loose texture, dissimilar crystals 
 mixed together, indicate an inferior quality. 
 
 Gray iron melts at a lower temperature than white 
 iron, becomes more fluid, and preserves its fluidity 
 longer ; it runs smoothly ; the color of the metal is red, 
 and deeper in proportion as the heat is lower; it does 
 not stick to the ladle ; it fills the mould well ; contracts 
 
148 ' • , CANNON. MATEEIALS. 
 
 less ; and contains fewer cavities than white iron ; the 
 edges of a casting are sharp, and the surface smooth, 
 convex, and covered with carburet of iron. Gray iron 
 is the only kind suitable for making castings which 
 require great strength, such as cannon. Its tenacity 
 and specific gravity are diminished by slow cooling or 
 annealing. 
 
 White iron is very brittle and sonorous ; it resists 
 the file and the chisel, aud is susceptible of high polish ; 
 the surface of the casting is concave; the fracture pre- 
 sents a silvery appearance, generally fine-grained and 
 compact, sometimes radiating, or lamellar. Its qualities 
 are the reverse of those of gray iron ; it is therefore 
 unsuitable for ordnance purposes. Its tenacity is in- 
 creased, and its specific gravity diminished by annealing. 
 Its mean specific gravity is 7.500, while that of gray 
 iron is only 7.200. 
 
 Mottled iron is a mixture of white and gray ; it has a 
 spotted appearance — hence its name ; it flows well, and 
 with few sparks ; the casting has a plane surface, with 
 edges slightly rounded. It is suitable for making shot 
 and shells. 
 
 Besides these general divisions, the manufacturers dis- 
 tinguish more particularly the different varieties of pig- 
 metal by numbers, from 1 to 6, according to their relative 
 hardness. 
 
 The qualities of these various kinds of iron would 
 seem to depend on the proportion of carbon and the 
 state in which it is found in the metal. In the darker 
 kinds of iron, where the proportion is sometimes 7 per 
 cent, of carbon, it exists partly in the state of graphite, 
 or plumbago, which makes the iron soft. In white iron, 
 
COMBINED METALS. 149 
 
 the carbon is thoroughly combined with the metal, as in 
 steel. 
 
 Cast iron frequently retains a portion of foreign in- 
 gredients from the ore, such as earths, or oxides of other 
 metals, and sometimes sulphur and phosphorus, which 
 are all injurious to its quality. Sulphur hardens the 
 iron, and unless in very small proportions, destroys its 
 tenacity. These foreign substances, and also a portion 
 of the carbon, are separated by melting the iron in con- 
 tact with air ; and soft iron is thus rendered harder and 
 stronger. 
 
 All cast iron expands forcibly at the moment of be- 
 coming solid, and again contracts in cooling ; gray iron, 
 as before remarked, expands more, and contracts less, 
 than other iron — an important fact in considering the 
 effect of unequal cooling. 
 
 The color and texture of cast iron depend greatly on 
 the size of the casting and the rapidity of cooling : a 
 small casting, which cools quickly, is almost always 
 white ; and the surface of large castings partakes more 
 of the qualities of white metal than the interior. 
 
 112. Combined metai§. Numerous trials have been 
 made to improve the strength of cannon, by combining 
 two or more metals in such a way that the good quali- 
 ties of one shall counteract the defects of the others. 
 For instance, it has been sought to increase the hard- 
 ness of bronze cannon by casting the metal around a 
 core of cast or wrought iron; and to increase the 
 strength of cast-iron cannon by enveloping them in 
 hoops of wrought iron, " shrunk on" in the process of 
 cooling. 
 
 The principal objections, in theory, to such combina- 
 
150 CANNON. MATERIALS. 
 
 tions arise from the unequal tensile, expansile, and elas- 
 tic properties of the different metals, and the want of 
 strength and solidity in the union of the different parts. 
 
 Armstrong and Mallet. The most noted instances of 
 " built-up" cannon of the present day, are Armstrong's 
 Rifle Gun, and Mallet's Monster Mortar. The former is 
 made by wrapping strips of wrought iron spirally around 
 a tube of the same material, which constitutes the sides 
 of the bore. The strip of each layer is welded together 
 at its edges, and it runs in a crosswise direction to that 
 of the layer which precedes it. This method makes a 
 very strong but a very expensive gun. 
 
 The latter is formed of three compound wrought-iron 
 rings, or cylinders, placed one upon the other, so as to 
 constitute the chase and reinforce of the piece. The 
 breech is made by embedding the wrought-iron chamber 
 in a large mass of cast iron, and the chase and reinforce 
 are fastened to it by longitudinal rods running along 
 the outside of the piece. 
 
 The bore of this mortar was 36 inches diameter, and 
 the bursting charge of the shell was 480 lbs. of powder. 
 Although it was tried with only one-half the intended 
 charge, it proved deficient in strength. 
 
 Treadwell. Professor Treadwell, of Cambridge, Mass., 
 who has had considerable experience in the manufacture 
 of steel and wrought-iron cannon, proposes a veryj inge- 
 nious plan of making cannon of cast and wrought iron.* 
 The core of the piece is formed of a tube of cast iron, 
 
 * The Parrott rifle gun, at present extensively used in our field service, is a light 
 cast-iron gun, strengthened by shrinking a band of wrought iron around that part 
 of the gun which surrounds the seat of the charge. The pieces of this kind now in 
 use are the 10-pdr. and 20-pdr. A 30-pdr. for siege and a 100-pdr. for sea-coast 
 service have also been prepared. 
 
TO DETERMINE PRESSURE. 151 
 
 the thickness of which is about one-half of the thickness 
 of an ordinary cannon. This he considers sufficient to 
 resist the pressure of the charge on the bottom of the 
 bore. The core is then surrounded by successive layers 
 of wrought-iron hoops, each u shrunk on" with a pres- 
 sure proportional to the square of its distance from the 
 centre, in order that all may be brought to the point 
 of rupture at the same instant, if necessary. 
 
 EXTEKIOK FORM. 
 
 113. Thickness of metal. The exterior form of can- 
 non is determined by the variable thickness of the metal 
 which surrounds the bore at different points of its 
 length. In general terms, the thickness is greatest at 
 the seat of the charge, and least at or near the muzzle. 
 This arrangement is made on account of the variable 
 action of the powder and projectile along the bore, and 
 the necessity of disposing the metal in the safest and 
 most economical manner, or, in other words, to propor- 
 tion it according to the strain it is required to bear. 
 
 114. To determine the pressure by calculation. It has 
 been proposed to determine the pressure of the powder 
 at the different points of the bore, by supposing all the 
 gases evolved in the first moment of combustion, and, 
 as the space behind the projectile increased, applying 
 Mariotte's law, that the tension of gas is proportional 
 to its density, which, in turn, is inversely proportional 
 to the space passed over by the projectile. This method 
 of determining the pressure gives a very rapid taper to 
 the exterior ; and however well it may answer for cast- 
 iron cannon, is unsuitable for those made of bronze ; 
 
152 CANNON. EXTERIOR FORM. 
 
 which are found, in practice, to burst in the chase, in con- 
 sequence of the enlargement of the bore from the striking 
 of the projectile against its sides. 
 
 A more correct method of calculating the pressure is 
 to apply the principles laid down in Chap. I. 
 
 In the case of a French 12-pdr. field gun, which is 
 fired with a charge of £ the weight of the projectile, the 
 formulas show that the projectile is moved 1.9 in. when 
 the gases have reached their maximum density of 0.38, 
 water being taken as unity. 
 
 Substituting this value in Rumford's formula, it will 
 be found that the mean pressure of the charge, on the 
 surrounding surface, is 1,500 atmospheres ; and with 
 powder made by the English, or " rolling-mill" process, 
 the mean pressure is found to be as high as 2,400 atmos- 
 pheres. The pressure at other points may be deter- 
 mined in a like manner. 
 
 115. Determination of pressure by experiment. About 
 the year 1841, Colonel Bomford devised a plan for de- 
 termining the pressure at various points of the bore by 
 direct experiment. It essentially consists in boring a 
 series of small holes through the side of a gun, at right 
 angles to its axis (see fig. 33), the first hole being placed 
 at the seat of the charge, and the others at intervals of 
 one calibre. A steel ball was projected from each hole, in 
 succession, into a target or ballistic pendulum, by the 
 force of the charge acting through it ; and the pressures 
 at the various points were deduced from the velocities 
 communicated to the balls ; it was by this means that the 
 form of the columbiads was determined. This plan has 
 been lately tried in Prussia with great care and success. 
 
 Instead of the projectile, Captain Rodman uses a steel 
 
NATURE OF FORCE TO BE RESTRAINED. 
 
 153 
 
 punch which is pressed by the force of the charge into 
 a piece of soft copper. The weight necessary to make 
 an equal indentation in the same piece, is then ascer- 
 tained by the " testing machine," or machine employed 
 to determine the strength of cannon materials. This 
 instrument is known as the "pressure piston," and is 
 used in proving powder to measure the strain which is 
 exerted on the bore of the eprouvette, or gun. 
 
 The following diagram shows the results obtained by 
 this apparatus applied to a 42-pdr. gun.* 
 
 12 
 
 1U Calibers. 
 
 8 
 
 Fig. 33. 
 
 116. Nature of force to be restrained. In estima- 
 ting the effect of any force upon a yielding material to 
 which it may be applied, the rate of application, or the 
 time which elapses from the instant when the force 
 begins to act until it attains its maximum, should not 
 be neglected ; for, with equal ultimate pressures per 
 square inch of surface, that powder will be most severe 
 
 * The data from which the above diagram was constructed, were taken from 
 experiments made by Captain Rodman, to compare the effect of hollow cake-pow- 
 der, with the ordinary grained powder. 
 
 The ordinates of the curved, show the pressures on the bore at intervals of two 
 calibres, commencing at the bottom of the bore, for the grain-powder ; and those of 
 the curve B the same for " cake-powder." The gun being suspended as a pendu- 
 lum, and the recoil being equal, or nearly so, it follows that nearly the same velocity 
 
154 
 
 CANNON. EXTERIOR FORM. 
 
 upon the gun which attains this pressure in the shortest 
 period of time after ignition. The smaller the grain 
 the more rapid will be the combustion of any charge 
 of powder (other things being equal), and hence the 
 greater will be the strain on the gun in which it is 
 burned.* 
 
 117. Various kinds of strain. The strains to which all 
 fire-arms are subjected, are four in number, viz. : 
 
 1st. The tangential strain, which acts to split the 
 piece open longitudinally, and is similar in its action to 
 the force which bursts the hoops of a barrel. 
 
 2d. The longitudinal strain, which acts to pull the 
 piece apart in the direction of its length. Its action is 
 the greatest at or near the bottom of the bore, and least 
 at the muzzle, where it is nothing. 
 
 These two strains increase the volume of the metal to 
 which they are applied. 
 
 3d. A strain of compression, which acts from the axis 
 
 was communicated to the projectile by the •* cake" as by the grain powder, with 
 only about one-half the mean pressure on the length of the bore. 
 
 
 
 Caked Powder. 
 
 Grained Powder. 
 
 No. 
 
 Distance from 
 
 
 
 
 
 
 
 of 
 
 bottom of 
 
 Pressure, 
 
 
 
 
 
 Pressure, 
 
 fires 
 
 the bore. 
 
 per square inch. 
 
 Kecoil. 
 
 Eecoil. 
 
 per square inch. 
 
 3 
 
 
 
 10.989 
 
 22° 
 
 24' 
 
 22° 
 
 58' 
 
 41.289 
 
 3 
 
 2 Calibres. 
 
 26.001 
 
 24° 
 
 21' 
 
 22° 
 
 56' 
 
 57.512 
 
 3 
 
 4 
 
 12.457 
 
 22° 
 
 57' 
 
 22° 
 
 59' 
 
 14.103 
 
 3 
 
 6 
 
 8.620 
 
 25o 
 
 43' 
 
 23° 
 
 05' 
 
 10.878 
 
 3 
 
 8 
 
 5.801 
 
 24° 
 
 12' 
 
 22° 
 
 53' 
 
 10.417 
 
 3 
 
 10 
 
 4.870 
 
 21° 
 
 43' 
 
 22° 
 
 49' 
 
 7.127 
 
 3 
 
 12 
 
 4.071 
 
 22° 
 
 07' 
 
 22° 
 
 55' 
 
 8.932 
 
 3 
 
 14 " 
 
 4.071 
 
 21° 
 
 42' 
 
 22° 
 
 49' 
 
 9.007 
 
 * Eeport of Experiments, by Captain Rodman, to Colonel of Ordnance. 
 
KINDS OF STRAIN. 
 
 155 
 
 outward, to crush the truncated wedges of which a unit 
 of length of the piece may be supposed to consist, and 
 to give a cross-section the shape shown in the diagram 
 (fig. A). This strain 
 compresses the metal and 
 enlarges the bore. If the 
 metal were incompressi- 
 ble, the appearance of a 
 cross-section of the rup- 
 ture would be that of fig. B ; and no enlargement of 
 the bore would result from the crushing of the metal ; 
 and any enlargement of the bore caused by the action of 
 the tangential force, would be accompanied by an equal 
 enlargement of the exterior diameter of the piece ; and 
 hence the strain upon the metal, at the inner and outer 
 surfaces of the gun, would be inversely as the radii of 
 these surfaces, instead of inversely as their squares (as 
 in the case of a compressible material). This quality 
 would bring into action one-third more tangential re- 
 sistance than the same metal would be capable of offer- 
 ing to a central force. 
 
 4th. A transverse strain, which acts to break trans- 
 versely, by bending outward the staves of which the 
 piece may be supposed to 
 
 consist. This strain com- 
 presses the metal on the 
 inner, and extends it on 
 the outer surface. The 
 resistance which a bar of iron, supported at its extrem- 
 ities, will offer to a pressure uniformly distributed over 
 it, is directly as the square of its depth, and inversely 
 as the square of its length ; and this is the same as the 
 
156 CANNON. EXTERIOR FORM. 
 
 resistance offered by a stave of the piece when support- 
 ed at the points d and b. 
 
 If p be the pressure on a unit of surface of the bore, 
 and s the tensile strength of the metal, it can be shown 
 by analysis, that the tendency to rupture, or the pres- 
 sure on a unit of length of the bore, divided by the 
 resistance which the sides are capable of offering to 
 rupture, for a piece of one calibre thickness of metal, 
 will be as follows, viz. : 
 
 Tangential, 3E; 
 
 or, rupture will take place when three times the pres- 
 sure is greater than twice the tensile strength. 
 
 Longitudinal, £-\ 
 
 or, rupture will take place in the direction of the length 
 when the pressure is greater than twice the tensile 
 strength. 
 
 Transverse, ^2; % 
 
 7 3s' 
 
 or, rupture will take place when twice the pressure is 
 greater than three times the tensile strength. 
 
 From the above it appears, that the tendency to rup- 
 ture is greater from the action of the tangential force 
 than for any other ; and for lengths above two, or per- 
 haps three, calibres, "the tangential resistance may be 
 said to act alone, as the aid derived from the transverse 
 resistance will be but trifling, for greater lengths of 
 bore or stave; but for lengths of bore less than two 
 calibres, this resistance will be aided by both the trans- 
 verse and the longitudinal resistance. Every piece 
 should, therefore, have sufficient thickness of breech to 
 
DIVISION OF THE EXTEEIOE. 157 
 
 cause rupture to take place (if at all) along the lines, 
 b c and d e (fig. 35), instead of splitting through the 
 breech ; and after this point has been attained, any ad- 
 ditional thickness of breech adds nothing to the strength 
 of the piece. 
 
 From the foregoing, we conclude that a fire-arm is 
 strongest at or near the bottom of the bore, and that 
 its strength is diminished rapidly as the length of the 
 bore increases, to a certain point (probably not more 
 than three calibres from the bottom); after which, for 
 equal thicknesses of metal, its strength becomes sen- 
 sibly uniform. 
 
 / 118. Division of the exterior.* The exterior of a can- 
 ' l nbn is generally divided into five principal parts, viz. : 
 the breech, the 1st reinforce, the 2d reinforce, the chase, 
 and the swell of the muzzle. See fig. 26. 
 
 The breech. The breech, or thickness of metal in the 
 prolongation of the axis of the bore, should be at least 
 equal to 1-]- times the diameter of the bore. A thick- 
 ness of one diameter has been found insufficient for 
 heavy iron guns. 
 
 First reinforce. This part extends from the base-ring 
 
 * The following formula, which is used for calculating the exterior form of can- 
 non of large calibre for the land service, was deduced by Captain Rodman from a 
 series of original experiments on the strength of hollow cylinders, &c. : 
 
 C-- ^— X 
 
 S ~ (R— r) (2 r L + R (R + r) (R— r) V 
 
 V) 
 
 in which C is a constant quantity, r = interior radius, and R = exterior radius, p =*= 
 pressure of gas, 1= length of bore pressed, required to fully develop transverse 
 resistance, L= length of bore corresponding to assumed values of R, S= tensile 
 strength of metal, and 1' = length of bore subjected to maximum pressure. The 
 pressure of the gas is supposed to vary inversely as the square root of the length of 
 the bore behind the projectile. The exterior forms thus obtained are entirely made 
 up of curved lines, and a specimen of them is seen in fig. 46, which represents that 
 of the new columbiads. 
 
 UNIVERS! 
 
158 CANNON. EXTERIOR FORM. 
 
 to the seat of the ball, and is the thickest part of 
 the piece, for the reason that the pressure of the 
 powder is found, both by experiment and calculation, 
 to be greatest before the projectile is moved far from 
 its place. The shape of this reinforce was formerly 
 made slightly conical, under the impression that the 
 pressure was greater at the vent than at the seat of 
 the projectile ; but it is now made cylindrical through- 
 out. For bronze cannon, the thickness of this part 
 is approximately given by the empirical formula in 
 
 fcW3. 
 
 E=D\J x"p> w hh?h D represents the diameter of a 
 
 solid cast-iron shot suited to the bore; O the proof 
 charge ; and P the real weight of the projectile. For 
 cast-iron cannon, E should be multiplied by the coeffi 
 cient 1.17. In general terms, the thickness of a bronze 
 gun, at the seat of the charge, is a little less, and of a 
 cast-iron gun a little greater, than the diameter of the 
 bore. These dimensions exceed those determined by 
 calculation, but are necessary to enable the piece to 
 resist the shocks of the projectile, &c. 
 
 Second reinforce. This portion of the piece connects 
 the first reinforce with the chase. It is made considera- 
 bly thicker than necessary to resist the pressure of the 
 powder, in order to serve as a proper point of support for 
 the trunnions, and to compensate for certain defects of 
 metal liable to occur in the vicinity of the trunnions of 
 all cast cannon, arising from the crystalline arrange- 
 ment, and unequal cooling of the different parts. 
 
 Chase. From the extremity of the second reinforce, 
 cannon taper more or less rapidly to the vicinity of the 
 
DIVISION OF THE EXTERIOR. 159 
 
 muzzle. This part is called the chase, and constitutes 
 the largest portion of the piece in front of the trunnions. 
 The principal injury to which the chase is liable, arises 
 from the striking of the ball against the side of the 
 bore ; and the thickness of metal should be sufficient to 
 resist it. In pieces of soft iron, or bronze, the indenta- 
 tions thus made by the projectile may increase to the 
 extent of bursting the piece ; but in cast-iron cannon, 
 where they never exceed 0.02 inch, the taper of the 
 chase can be made more rapid, or, with the same weight 
 of metal, longer than in bronze guns. An example of 
 this is seen in the Dahlgren guns of the naval service. 
 
 For many years, cast-iron cannon have been made in 
 Sweden of a form nearly approaching that called for by 
 the actual pressure of the powder at different points of 
 the bore. See fig. 36. 
 
 V — = 
 
 Fig. 36. 
 
 In the construction of bronze guns, the thickness of 
 the metal at the neck, or thinnest part, is about equal 
 to -f' T of that at the first reinforce, or T 5 T JE, given in the 
 empirical formula on p. 158. 
 
 Sivell of the muzzle. Inasmuch as the metal situated 
 immediately at the muzzle, is supported, only in rear, it 
 has been usually considered necessary to increase its 
 thickness, to enable it to resist the action of the projec- 
 tile at this point. This enlargement is called the swell 
 of the muzzle. At present, the practice is to reduce the 
 
160 CANNON. EXTERIOR FORM. 
 
 diameter of the swell of tlie muzzle of all cannon, and 
 particularly that of heavy iron cannon, designed to be 
 fired through embrasures. By a late order of the war 
 department, the swell is to be hereafter omitted from 
 all sea-coast cannon. 
 
 In field and siege howitzers, the muzzle band takes 
 the place of the swell. 
 
 All projections on the surface of cannon, not abso- 
 lutely necessary for the service of the piece, are omitted 
 in cannon of late models. This omission simplifies their 
 construction, renders them easier to clean, and obviates 
 certain injurious strains that would otherwise arise from 
 unequal cooling in fabrication. 
 
 119. Trunnions. The trunnions are two cylin- 
 drical arms attached to the sides of a cannon, for the 
 purpose of supporting it on its carriage. They are 
 placed on opposite sides of the piece, with their axes in 
 the same line, and at right angles to its axis. 
 
 Size. The size of the trunnions depends on the recoil 
 of the piece, and the material of which they are made. 
 The resistance which a cylinder opposes to rupture, is 
 proportional to the cube of its diameter, or the weight 
 of a sphere of the same diameter. On the supposition 
 that the strain is proportional to the weight of the 
 charge, it is laid down as a rule that the diameter of 
 the trunnions of guns shall be equal to the diameter of 
 the bore, and the diameter of the trunnions of how- 
 itzers shall be equal to the diameter of their cham- 
 bers — the recoil being less than for guns of the same 
 calibre. 
 
 Position. The position of the trunnions, with refer- 
 ence to the axis of the bore, influences the amount of 
 
TKUNNIONS. 161 
 
 recoil, tlie endurance of the carriage, and the extent of 
 the vertical field of fire. 
 
 Fig. 37. 
 
 By reference to the figure, it will be seen that if the 
 axis of the trunnions be placed below the axis of the 
 piece, the resultant of the force of the charge, which 
 acts against the bottom of the bore, will act to turn the 
 piece around its trunnion, and cause the breech to press 
 upon the head of the elevating screw, with a force pro- 
 portioned to the length of the lever arm, or distance be- 
 tween the axes. The effect will be to press the trail on 
 the ground and check the recoil — thereby throwing an 
 additional strain on the carriage. 
 
 If the trunnions be placed above the axis of the 
 piece, rotation will take place in the opposite direction, 
 and the effects of the discharge on the carriage and re- 
 coil will be reversed. By placing the two axes in the 
 same plane, the force of the charge will be communi- 
 cated directly to the trunnions, without increasing or 
 diminishing its effect on the carriage, or recoil; this 
 position is given to them in all the cannon of the United 
 States service. 
 
 It is evident that the space between the lower side 
 of the piece and the carriage, limits the amount of ele- 
 vation or depression that can be given to the piece, and 
 that the greatest angle of fire can be attained when the 
 axis of the trunnions is situated below the axis of the 
 piece. 
 
 120. Preponderance. The unequal distribution of 
 11 
 
162 CANNON. EXTERIOR FORM. 
 
 the weight of a piece of artillery, with reference to the 
 axis of the trunnions, is called the preponderance, the 
 object of which is to give it stability in transportation 
 and firing, by producing a pressure on a third point of 
 support, generally the head of the elevating screw. In 
 all guns and howitzers, the centre of gravity is situated 
 in rear of the trunnions, and in all mortars it is situated 
 in front of them* 
 
 Formerly it was measured by the weight which it 
 was necessary to apply to the plane of the muzzle to 
 balance the piece, when suspended freely at the axis of 
 the trunnions ; but in pieces of late model it is con- 
 sidered equal to the pressure exerted on the head of 
 the elevating screw, or a third point of support. 
 
 The position of the trunnions, with reference to the 
 length of the piece, is an important consideration in 
 siege and sea-coast cannon, for by placing them further 
 to the rear, the piece can be elevated and depressed 
 more rapidly, and its penetration into the embrasure is 
 increased. 
 
 121. Rimba§es. Rimbases are two larger cylinders 
 (b £), placed concentrically around 
 the trunnions, for the purpose of 
 strengthening them at their junc- 
 tion with the piece, and by form- 
 ing shoulders, to prevent the piece 
 from moving sideways in the trun- 
 Fig ' 38 ' nion-beds. 
 
 * The mortars and eolumbiads modelled in 1861 have no preponderance, as the 
 axis of the trunnions intersects the axis of the piece at the centre of gravity. Cap- 
 tain Rodman has shown that, contrary to the generally-received opinion, cannon 
 constructed in this way are found not to sensibly change their position before the 
 projectile leaves the bore — and that the accuracy of the fire is not affected. 
 
TRUNNIONS. 163 
 
 122. Knob of the cascabie. This is a projection affixed 
 to the breech of a cannon, for the purpose of attaching 
 the sling in mounting and dismounting it from its car- 
 riage. Its axis is that of the bore prolonged. 
 
 123. Handier These are two projections (c c,fig. 38,) 
 placed over the centre of gravity of certain bronze field- 
 pieces, for manoeuvring purposes. 
 
 In the heavy sea-coast mortars, the handle is replaced 
 by a clevis attached to a projection cast on the piece. 
 
 124. Portion of the centre of gravity. Having deter- 
 mined the precise form of each part of a cannon, it be- 
 comes necessary to place the trunnions so that the breech 
 shall exert a given pressure on the head of the elevating 
 screw ; or in other words, so that the piece shall have a 
 certain preponderance. 
 
 In making the computation, it will be necessary to 
 know the position of the centre of gravity of the piece ; 
 and this may be determined from the principle, that the 
 sum of the moments of the weight of the several parts 
 is equal to the moment of the weight of the entire piece. 
 For convenience, let the plane of reference be taken 
 tangent to the knob of the cascabie, and at right angles 
 to its axis. 
 
 Let a be the volume of the breech and cascabie, 
 b u " 1st reinforce, 
 
 o " " 2d " 
 
 d u " trunnions and rimbases, 
 
 e tt " chase, 
 
 f u swell of muzzle and 
 
 mouldings, 
 g " bore, including the 
 
 chamber, 
 
164 CANNON. EXTERIOR FORM. 
 
 and a' , b\ <fcc., the distances of the centre of gravity of 
 each part from the plane of reference, respectively. 
 Let w be the weight of a unit of volume of the piece, 
 W the weight of the piece, and x the distance of its 
 centre of gravity from the plane of reference. 
 
 Taking the sum of the moments of all the parts, 
 diminishing it by the moment of the bore, and placing 
 the remainder equal to the moment of the piece, we 
 have the relation : 
 
 (aa'+bb'+cc'+dd'+ee'+ff-gg')™ 
 W 
 
 Cancelling the unit of weight in the numerator and 
 denominator of the second member of the above equa- 
 tion, the distance of the centre of gravity of any cannon, 
 from either extremity, is equal to the algebraic sum of 
 the products of the volumes of the parts by the distances 
 of their centres of gravity from that extremity, divided 
 by the volume of the metal. 
 
 The weight of the piece is supported by the elevat- 
 ing screw and trunnions. The pressure on the screw, 
 and its distance from the centre of gravity, are known ; 
 and the distance which the trunnions should be placed 
 in front of the centre of gravity, to support the re- 
 mainder of the weight, will become known from the 
 
 proportion 
 
 p : ( W—p) ::y:l 
 
 in which p represents the preponderance, I the distance 
 of the head of the elevating screw from the centre of 
 gravity, (W—p) the weight to be sustained by the 
 
WEIGHT OF CANNON. 165 
 
 trunnions, and y the distance of their axis from the 
 centre of gravity. 
 
 125. Weight of cannon. The weight of a cannon is 
 determined by the weight of the projectile, the maxi- 
 mum velocity it may be necessary to communicate to 
 it, and the extent of the recoil. 
 
 The extent of the recoil being limited by the con- 
 ditions of the service, the weight of the piece may 
 be deduced from the principle, that action and reaction 
 are equal and opposite; or, that the quantity of motion 
 expended on the piece, carriage, and friction, is equal 
 to that expended on the projectile, and the air set in 
 motion by the charge. 
 
 Let w be the weight of the projectile, 
 v its maximum velocity, 
 the weight of the charge of powder, 
 N a constant linear quantity, representing the 
 velocity communicated to the piece by a 
 unit of the charge, arising from its action 
 on the air, independent of the projectile. 
 For American powder, this has been found 
 by experiment with the gun and ballistic 
 pendulums, to be equal to 1,600 feet. 
 / the velocity lost by a unit of mass, from the 
 friction of the carriage on ordinary ground, 
 W the weight of the piece, 
 V velocity of recoil, 
 the weight of the carriage, 
 R the pressure of the trail on the ground, arising 
 
 from the recoil, 
 g the force of gravity. 
 
166 CANNON. DIFFERENT KINDS. 
 
 From the principle before enunciated, we have 
 
 g 9 g 9 
 
 or, by reduction, 
 
 w _wv+c N- CV- Cf-Bf 
 
 For field-guns, the velocity of the recoil should not 
 exceed 12 feet. 
 
 DIFFERENT KINDS OF CANNON. 
 
 126. Gun. In a technical sense, a gun is a heavy 
 cannon, intended to throw solid shot with large charges 
 of powder, for the purpose of attaining great range, ac- 
 curacy, and penetration. 
 
 It may be distinguished from other cannon by its 
 great weight and length, and by the absence of a cham- 
 ber. 
 
 The gun is suited to fire hollow as well as solid pro- 
 jectiles ; and the only limit to the charge is the strength 
 of the projectile to resist rupture in the piece. The em- 
 ployment of shells in heavy cannon, after the manner 
 of solid shot, constitutes the basis of what is known as 
 General Paixhan's System of Artillery, and not the pe- 
 culiar form of the gun, as is generally supposed. 
 
 The calibre of a gun is generally expressed in terms 
 of the weight of a solid cast-iron ball of the size of the 
 bore. 
 
 127. Howitzer. The howitzer is a cannon employed 
 to throw large projectiles with comparatively small 
 
RIFLED CANNON. 167 
 
 charges of powder. It is shorter, lighter, and more 
 cylindrical in shape than a gun of the same calibre ; 
 and it has a chamber for the reception of the powder, 
 generally of a cylindrical form. 
 
 The chief advantage of a howitzer over a gun, is, 
 that with less weight of piece, it can produce at short 
 ranges a greater effect with hollow projectiles and case 
 shot. It also affords the means of attaining an enemy 
 sheltered from the direct fire of solid shot. 
 
 The calibre of a howitzer may be expressed in terms 
 of the weight of solid shot, as in guns ; or it may be 
 expressed in terms of the diameter of the bore in 
 inches. 
 
 128. Ufortars. A mortar is a short and comparative- 
 ly light cannon, employed to throw large, hollow projec- 
 tiles, at great angles of elevation. It has a chamber, 
 generally of a conical form, and of a size suited to a 
 small charge of powder, compared to the weight of the 
 projectile. The trunnions of all mortars are attached 
 to the breach for convenience of elevation and depres- 
 sion. (See note at the bottom of page 162.) 
 
 Mortars are particularly intended to produce effect 
 by the force with which the projectiles descend upon 
 their objects, and by the force wdth which they explode. 
 They are employed chiefly against inanimate objects, 
 such as the roofs of buildings, magazines, and case- 
 mates, and the decks of ships of war. 
 
 KIFLE-CANNON. 
 
 129. Definition. A rifle is a fire-arm which has cer- 
 tain spiral grooves (or " rifles") cut into the surface of 
 
168 CANNON. RIFLED. 
 
 its bore, for the purpose of communicating a rotary 
 motion to a projectile around an axis- coincident with its 
 flight. 
 
 The object of this rotation, or rifle-motion, as it is 
 generally called, is to increase the range of a projectile, 
 by causing it to move through the air in the direction 
 of its least resistance, and to correct the cause of devia- 
 tion, by distributing it uniformly around the line of 
 flight. Rifle-motion being only a particular case of the 
 general subject of rotation of projectiles, its peculiar 
 effects will be best explained and understood, in a sub- 
 sequent chapter. 
 
 130. Rifles— how clarified. Military rifles maybe di- 
 vided into rifle-cannon and rifle-muskets, or small arms, 
 which only differ in the practical application of the rifle 
 principle. The yielding nature of lead renders the 
 application of the rifle principle of easy accomplishment 
 in the case of rifle-muskets, but such is not the case with 
 rifle-cannon, where the projectiles are made of iron. 
 
 The principal question which now occupies the atten- 
 tion of persons engaged in improving this species of 
 cannon, is to obtain the safest and surest means of caus- 
 ing the projectile to follow the spiral grooves as it 
 passes along the bore of a rifled piece. Various plans 
 have been tried to attain the proposed object, some of 
 which promise to be successful. Nearly all may be 
 ranged under the following heads, viz. : 
 
 1st. Those which have certain flanges or projections 
 on the projectile, to fit into the grooves of the gun in 
 loading. This plan affords certain means of communi- 
 cating the rifle-motion, but it has not been found a safe 
 one ; probably, from the wedging of the flanges in the 
 
RIFLED CANNON. 169 
 
 grooves. Besides, the dirt from the burning of the pow- 
 der collects in the grooves ; and as it is difficult to clean 
 them by the usual means, the projectile is liable to meet 
 with obstruction in loading. 
 
 To obviate these difficulties, the flanges are sometimes 
 made of softer metal than the body of the projectile, as 
 in the case of the French rifled field-cannon. Flanges 
 that fit the grooves loosely in loading, but which ex- 
 pand when the piece is fired, so as to fit them tightly, 
 have been tried with some success. 
 
 2d. Those cannon in which the form of the bore is a 
 twisted prism, with an elliptical or polygonal base. If 
 the metal of the projectile be unyielding, its form must 
 be similar to that of the bore. If it be an expanding 
 projectile, its form may be slightly different from that of 
 the bore. 
 
 The hexagonal bore is one of the best for communi- 
 cating the rifle-motion to a projectile, as was shown by 
 the experiments of Mr. Whitworth, in England ; but the 
 experiments made with this form of bore in this country, 
 would indicate that it is not a safe one for ordinary cast- 
 iron cannon. 
 
 The elliptical bore, as tried in the Lancaster cannon, 
 did not meet with the success anticipated for it. 
 
 3d. Those cannon in which the projectile is con- 
 structed on an expanding principle. The body of an 
 expanding projectile is generally made of cast iron; and 
 the expanding portion is a band, or cup of some softer 
 metal, as pewter, copper, wrought iron, or papier-mache, 
 &c. which enters the bore freely when the piece is loaded, 
 but which is forced into the grooves by the discharge. 
 Projectiles of this class are generally as easily loaded as 
 
170 CANNON. KIFLED. 
 
 ordinary projectiles, and if properly constructed, do not 
 overstrain the piece. 
 
 The principal objections to an expanding, or compound 
 projectile, are its want of strength to resist a charge of 
 powder, proportionately as large as that employed for 
 a simple projectile, and the danger of its breaking and 
 wedging in the bore of the piece. 
 
 The projectile adopted for the United States land ser- 
 vice was devised by Major Dyer, of the ordnance de- 
 partment, in 1857. It belongs to the ex- 
 panding class, and is composed of a cast- 
 iron body (a), and an expanding cup of 
 soft metal (V), which is formed of an alloy 
 of lead and antimony. 
 
 The cup and body are firmly united in 
 the process of casting by covering the 
 surface of contact with tin. The dis- 
 charge forces the sides of the cup into 
 Mg. 39. the grooves, and thereby compels the 
 
 projectile to take up the rifle motion. 
 
 4th. This head embraces those projectiles which are 
 inserted into the bore through an opening in the breech 
 of the piece, and receive their rotary motion by passing 
 through a bore, the diameter of which is slightly less 
 than that of the projectile. This peculiar operation, of 
 forcing the projectile into the grooves of the bore, is 
 technically called slugging, and can only be applied to 
 projectiles made, wholly or partially, of a yielding 
 metal* 
 
 The breech-loading principle secures for the projectile 
 
 * For a general description of the other more prominent projectiles used in the 
 United States, see appendix. 
 
UNIFORM GROOVE. lYl 
 
 the required rifle-motion with great certainty, and affords 
 increased facilities for loading cannon designed to be 
 fired through an embrasure ; but it is not generally con- 
 sidered a safe principle to apply to large cannon made 
 of cast iron in the usual way. 
 
 131. Form of groove. The form of a rifle groove is 
 determined by the angle which the tangent at any point 
 makes with the corresponding element of the bore. If 
 the angles be equal at all points, the groove is said to 
 be uniform. If they increase from the breech to the 
 muzzle, the grooves are called increasing, if the reverse, 
 decreasing grooves. 
 
 Twist is the term generally used by gun-makers, to 
 express the inclination of a groove at any point, and is 
 measured by the length of a cylinder corresponding to a 
 single revolution of the spiral ; this, however, does not 
 convey a correct idea of the inclination of a groove. A 
 correct measure of the inclination of a rifle groove at 
 any point, is the tangent of the angle which it makes 
 with the axis of the bore ; and this is always equal to 
 the circumference of the bore divided by the length of a 
 single revolution of the spiral, measured in the direction 
 of the axis. 
 
 132. Uniform groove. To construct the development 
 of a uniform groove, let A B be the base 
 of a rectangle, equal to the circumference 
 of the bore ; B C, the height equal to the 
 length of a single revolution of the spiral, 
 measured on the axis of the bore. The 
 diagonal A O is the development of an 
 entire revolution of the required groove. 
 
 Fig. 40. On the line A D lay off the distance 
 
172 CANNON. KIFLED. 
 
 A d, equal to the length of the bore ; at d erect a 
 perpendicular, and the line A c will be that portion 
 of the development of the groove which lies on the 
 surface of the bore. 
 
 133. Variable groove. Variable grooves are con- 
 structed by wrapping a curve around the surface of the 
 bore. The curve generally selected for this purpose, is 
 the arc of a circle. 
 
 To construct the development of an increasing groove 
 which shall be the arc of a circle : The known condi- 
 tions of construction are the length of the bore, and the 
 inclination, or twist, at the breech and at the muzzle. 
 The quantity to be determined is the radius of the gen- 
 erating circle. 
 
 Suppose the problem solved, and let B P represent 
 the element of the bore passing through the extremity 
 
 of the groove at the muz- 
 zle; P C, the tangent to 
 the groove at this point; 
 A the starting point of the 
 curve ; and A J) the tangent 
 Fig. 41. to the groove at this point. 
 
 The angle of the tangent and element at the breech, is 
 generally made zero, and is so considered in this par- 
 ticular case. The perpendiculars at A and P are radii 
 of the required circle, and their intersection, O y will be 
 its centre. 
 
 To determine the length of the radius A O, and the 
 versed sine of the arc A P: From the nature of 
 
 a circle, the angle CPB=AOP; BO= ^ 5, • 
 ' 5 ; tan. BOP' 
 
 and OP= i /BP 2 +B0 2 ; or, by substituting for BO 
 
METHOD OF CUTTING GROOVES. 173 
 
 its value, OP— \ BP 2 -\ irrrrrr* and AB— 
 
 V tan. 2 CPB 
 
 BP 2 BP 
 
 ttm. 2 CPB ttm.BOP 
 
 134. Method of cutting groove§. The practical method 
 of cutting grooves in cannon is essentially the same as 
 in small arms. It consists in moving a rod, armed with 
 a cutter, back and forth in the bore, and at the same 
 time revolving it around its axis. If the velocities of 
 translation and rotation be both uniform, the grooves 
 will have a uniform twist ; if one of the velocities be vari- 
 able, the grooves will be either increasing or decreasing, 
 depending on the relative velocities in the two directions. 
 
 135. Comparative advantages The comparative ad- 
 vantages of uniform and variable grooves, depend on 
 the means used to connect them with the projectiles. 
 If the bearing of the projectile in the grooves be long, 
 and the metal of which it is made be unyielding, it will 
 be unsafe, if not impracticable, to employ variable 
 grooves ; and if the metal be partially yielding, a portion 
 of the force of the charge will be expended in changing 
 the form of that part of the projectile which projects 
 into the grooves, as it moves along the bore. 
 
 When the portion in the grooves is so short that its 
 form will undergo but slight alteration, the increasing 
 groove may be used with advantage, as it diminishes 
 the friction of the projectile when it is first set in 
 motion, and thereby relieves the breech of the piece of 
 a portion of the enormous strain which is thrown upon 
 it. If the twist be too rapid toward the muzzle, there 
 will be danger of bursting the piece in the chase. 
 
174 CANNON. RIFLED. 
 
 It is claimed by some, that the variable groove is 
 well adapted to expanding projectiles with short bear- 
 ing surfaces ; but the uniform groove, being more sim- 
 ple in its construction, and nearly as accurate in its 
 results, is generally preferred for military fire-arms, both 
 large and small. 
 
 136. Number, width, and §hape of grooves. The 
 width of a groove depends on the diameter of the bore, 
 and the peculiar manner in which the groove receives 
 and holds the projectile. 
 
 Wide and shallow grooves are more easily filled by 
 the expanding portion of a projectile than those which 
 are narrow and deep ; and the same holds true of cir- 
 cular-shaped grooves, when compared to those of angu- 
 lar form. An increase in the number of grooves in- 
 creases the firmness with which a projectile is held, by 
 adding to the number of points which bear upon it. 
 
 It has been suggested that rifle-cannon, intended for 
 flanged projectiles, should have four grooves; as a 
 greater number increases the difficulties of loading, and 
 a lesser number does not hold the projectile with suffi- 
 cient steadiness. 
 
 For expanding projectiles, an odd number of grooves 
 is generally employed, for, as this places a groove op- 
 posite to a land, less expansion will be required to 
 fill them. The number of grooves used in the 3-inch 
 field-gun is seven, and the number used in 4i-inch siege- 
 guns is nine. The number of grooves in the 4-inch Arm- 
 strong gun isjlfty. 
 
 137. Initial velocity of rotation. Let l^be the ini- 
 tial velocity of the projectile, or space which it would 
 pass over in one second, in the direction of flight, 
 
INCLINATION OF GROOVES. 175 
 
 moving with the velocity with which it leaves the 
 piece, and I the distance passed over by the projectile 
 
 in making one revolution ; therefore, -=- will be the 
 
 number of revolutions in one second, and 27r— the 
 
 angular velocity of the projectile at the muzzle. The 
 velocity of rotation of a point on the surface is given 
 by the expression, 
 
 o V 
 I 
 
 in which r is its distance from the axis of motion, and 
 w is the angular velocity. 
 
 138. Inclination of grooves. The object of rifle- 
 grooves being to communicate an effective rotary motion 
 to a projectile throughout its flight, it remains to de- 
 termine what velocity of rotation, or inclination of 
 grooves, is necessary for different projectiles. 
 
 The velocity of rotation will depend on the form and 
 initial velocity of the projectile, the causes which re- 
 tard it, and the time of flight ; therefore, there is a par- 
 ticular inclination of grooves which is best suited to each 
 calibre, form of projectile, charge of powder, and angle 
 of fire. 
 
 It is proposed to investigate the effect of the length 
 and calibre of the projectile, on the inclination of the 
 grooves. 
 
 139. Effect of length. It has been noticed that if very 
 long projectiles be fired from the rifle-musket, they are 
 less accurate than the ordinary projectile, the length of 
 which is less than two calibres. Mr. Whitworth states 
 that he has known a bullet twice this length, turn over 
 
176 CANNON. RIFLED. 
 
 end for end, within six feet of the muzzle of the Eng- 
 lish rifle-musket, the calibre of which is nearly the same 
 as that of the American rifle-musket. 
 
 This instability undoubtedly arises from the want of 
 sufficient rotation around the long axis. What increase 
 of angular velocity must, therefore, be given to com- 
 pensate for a given increase of length of an oblong 
 projectile? 
 
 The resistance which a projectile offers to angular 
 deflection, when rotating around a principal axis, is pro- 
 portional to the moment of its quantity of motion taken 
 with reference to this axis, or 
 
 MWw, 
 M being the mass, Jo radius of gyration, and w the an- 
 gular velocity. 
 
 Let this expression represent the moment of the 
 quantity of motion around the long axis, and Tc t and w / 
 the radius of gyration, and angular velocity, around a 
 short axis, and suppose the angular velocities w and w / 
 to be such that the resistance to a deflection from the 
 axes shall be equal, we have 
 
 Mt?w=Mh 2 w„ 
 and by reduction, 
 
 W 
 
 Hence, if we determine by experiment the value of w, 
 the angular velocity necessary to give practicable sta- 
 bility of rotation, we can determine the value of w„ 
 and consequently the superior limit of the deflecting 
 forces. 
 
 Substituting the value of w / in a similar expression 
 for any other projectile, we can determine the angular 
 
EFFECT OF RESISTANCE OF THE AIR. 177 
 
 velocity, and from this the inclination of grooves neces- 
 sary to give the second projectile steadiness in flight. 
 
 The foregoing method of determining the relation 
 between the lengths of two rifle-projectiles, and the in- 
 clination of grooves necessary to give them equal stead- 
 iness of flight, is true only under the supposition that 
 they preserve throughout their range the relative an- 
 gular velocities with which they started. It is neces- 
 sary, therefore, to consider the causes which affect ro- 
 tation. 
 
 140. Effect of resistance of the air. The cause which 
 retards the rotary motion of a rifle-projectile, is the 
 friction of the air on its surface ; and its retarding effect 
 will be equal to its moment divided by the moment of 
 the projectile's quantity of motion. 
 
 Let f be the friction on a unit of surface ; » % the sur- 
 face of the projectile ; p, the distance of the resultant 
 moment of the friction from the axis of motion ; Jc, the 
 radius of gyration ; and v, the mean velocity of the pro- 
 jectile during its flight. The pressure of the air on the 
 projectile is nearly proportional to the square of its velo- 
 city : f $ v 2 will therefore represent the friction on the 
 projectile, and/ s v 2 p will be its moment. 
 
 The moment of the quantity of motion of the pro- 
 jectile is Mk 2 w, M being the mass, and w the angular 
 velocity. 
 
 The expression for the angular retardation is, there- 
 fore, 
 
 f$v 2 p 
 
 MwW' 
 
 To find the angular velocity that it is necessary to 
 give to another projectile, that it may experience the 
 
 12 
 
178 CANNON. RIFLED. 
 
 same retarding effect, place this expression equal to a 
 similar one, answering to this projectile, and we have : 
 
 fsv 2 p __fs / v 2 p / 
 
 Reducing, and recollecting that the surface is propor- 
 tional to the square, and the mass to the cube of the 
 mean diameter, we have : 
 
 v 2 p _ v 2 p, # 
 dWw~ d)c?w] 
 or, 
 
 v 2 p v 2 p. 
 
 in ' ?/; • • — * 
 
 • '" aw ' d t hy 
 
 Hence, if the angular velocity necessary for one rifle- 
 projectile be known, the angular velocity necessary for 
 another of similar form and material, but of different 
 size, may be determined by calculation. 
 
 Suppose the two projectiles to be round shot, and 
 moving with the same mean velocity, through the same 
 extent of trajectory, the proportion reduces to 
 
 But the angular velocity is inversely proportional to 
 
 the length of the twist ; it follows, therefore, that the 
 
 " length of twisf of grooves, for round shot, moving 
 
 through equal lengths of trajectory, and with equal mean 
 
 velocities, should be directly as the squares of their 
 
 diameters. 
 
 141. Po§ition of centre of gravity. The further the 
 
 centre of gravity of a projectile is in rear of the cen- 
 tre of figure, or resistance of the air, the greater will be 
 the levqr arm of the deviating force, and, consequently, 
 the greater must be the inclination of the grooves, to 
 
INCLINATION OF GKOOVES. 179 
 
 resist deviation. A conical projectile, of the same length 
 and diameter, requires a greater inclination of grooves 
 than a cylindrical projectile ; and the same will hold 
 true of other forms, as they approach one or the other of 
 these extreme cases. 
 
 142. Limit of inclination. The friction of the pro- 
 jectile as it passes along the grooves, increases with their 
 inclination ; its effect will be to diminish the range, and 
 increase the strain on the piece. It is easily to be seen 
 that the inclination may be carried so far as to break 
 the projectile, or rupture the piece. 
 
 143. Mo§t §uitabie inclination. The inclination of 
 grooves for a rifle-cannon, best suited to a given projec- 
 tile, has not yet been determined by experience ; and 
 the consequence is, that a wide diversity of " twists" is 
 employed in different services, and by different experi- 
 menters. Colonel Cavalli, in his experiments in Sweden, 
 obtained good results from twists of one turn in 12 feet, 
 and one turn in 35 feet, in a 32-pdr. gun ; and a still 
 greater variety of twists have been employed in our own 
 service. 
 
 For a projectile one and a half diameters long, and 
 6-pdr. calibre, excellent practice has been obtained with 
 a twist of 25 feet; and in a certain form of the Arm- 
 strong gun, the twist is 12 feet for a bore 4 inches in 
 diameter. 
 
 The twist of the new wrought-iron rifle-gun for field 
 service, is 10 feet, and the twist of the new siege gun 
 is 15 feet. The calibre of the former is 3 inches, and 
 the latter 4£ inches. 
 
180 CANNON. VAKIOUS USES OF. 
 
 USES TO WHICH CANNON ARE APPLIED. 
 
 Having discussed the general principles which govern 
 the construction of all cannon, it is now proposed to 
 consider the peculiarities which arise from the uses to 
 which the several kinds are applied. 
 
 144. Field-cannon. Field-cannon are intended to be 
 used in the operations of an army in the field; they 
 should, therefore, have the essential quality of mobility. 
 They are divided into light and heavy pieces. The 
 former are constructed to follow the rapid movements 
 of light troops and cavalry. The latter are employed 
 to follow the movements of heavy troops, to commence 
 an action at long distance, to defend field-works and 
 important positions on the field of battle, &c. ; hence 
 they are said to constitute " batteries of position." 
 
 The light pieces are the 6-pdr. gun and 12-pdr. how- 
 itzer. The heavy pieces are the 12-pdr. gun, 24-pdr. and 
 32-pdr. howitzers. 
 
 The detailed dimensions, &c, of all cannon for the 
 United States, land service, may be ascertained by refer- 
 ence to the Ordnance Manual ; but, in order that the 
 pupil may form a correct general idea of them, a few of 
 the most important data will be given under each head ; 
 and, to assist the memory, they will, as far as practica- 
 ble, be expressed in terms of the calibre. 
 
 Weight The weight of field-guns is about 150, and 
 howitzers, 100 times that of their projectiles. 
 
 Length of bore. As field-cannon are seldom used to 
 fire through embrasures, and as lightness is an indis- 
 pensable requisite, the length of the bore is confined 
 
FIELD CANNON. 181 
 
 to the shortest effective length for each kind and calibre. 
 For guns, it is about 16, and for howitzers, about 10 
 diameters. 
 
 Natural angle of sight The natural angle of sight 
 is 1°. 
 
 Material. In Sweden, field-cannon are made of cast 
 iron; in all other countries, of bronze. In 1840, cast- 
 iron field-cannon of American pattern, were made at one 
 of the most celebrated foundries in Sweden, brought to 
 this country, and subjected to extreme proof, by the side 
 of similar cannon made of American cast iron. The 
 result showed that American gun-iron was not inferior 
 to the Swedish; and it is the opinion of experienced 
 persons, that suitable field-cannon can be made of cast 
 iron. The small size, however, of these pieces, and the 
 absence of entire confidence in this material, have prob- 
 ably induced the proper authorities to adhere to bronze 
 as a material for all field-cannon. 
 
 Charge. The charges of powder for field service, in 
 terms of the solid shot, are, 
 
 For Guns. 
 Solid shot, shells, and spherical case, one-fifth. 
 Canister shot, one-sixth. 
 
 For Howitzers. 
 Shells and case-shot, one-twelfth. 
 
 Vertical field of fire. The vertical field of fire is 20°: 
 12° above, and 8° below the horizon. 
 
 The foregoing are some of the most important points 
 in the system of field cannon adopted in 1840 ; many 
 of the pieces of which are still in service. 
 
182 CANNON. VARIOUS USES OF. 
 
 145. The new field or Napoleon gun. In 1856 it was 
 proposed to increase the power of the light and dimin- 
 ish the weight of the heavy field-artillery, by the intro- 
 duction of a single piece of medium weight and calibre, 
 (see par. 76). 
 
 Fig. 42. 
 
 Form. The form of the new piece is shown in 
 fig. 42. It has no chamber, and should therefore be 
 classed as a gun. Its exterior is characterized by the 
 entire absence of moulding and ornament ; and in this 
 respect it may be at once distinguished from the old 
 field-cannon. The first reinforce is cylindrical ; and it 
 has no second reinforce, as the exterior tapers uniformly 
 with the chase from the extremity of the first reinforce. 
 The size of the trunnions and the distance between the 
 rimbases are the same as in the 24-pdr. howitzer, in 
 order that both pieces may be transported on the same 
 kind of carriage* 
 
 Dimensions, &c. The diameter of the bore is that of 
 a 12-pdr. The length of bore is 16 calibres. The weight 
 is 100 times the projectile, or 1,200 lbs. The charge of 
 powder is the same as for the heavy 12-pdrs. (pattern 
 of 1840), or 2^ lbs. for solid and case shot, and 2 lbs. 
 for canister shot. It has, therefore, nearly as great 
 
 * The new rifle-gun adopted for the field service is made of wrought iron, and 
 modelled after the plan of Captain Rodman. Its weight is 820 lbs., and the diam- 
 eter of the bore is 3 inches. The weight of the projectile is about 10 lbs., and the 
 charge of powder is 1 lb. The length of the bcre is 21 66 diameters. 
 
MOUNTAIN AND PRAIRIE CANNON. 183 
 
 range and accuracy as the heaviest gun of the old sys- 
 tem ; and, at the same time, the recoil and strain on the 
 carriage are not too severe. 
 
 The new gun and carriage weigh about 500 lbs. more 
 than the 6-pdr. and carriage ; still, it has been found to 
 possess sufficient mobility for the general purposes of 
 light artillery. It is proposed to retain the 12-pdr. 
 howitzer in service, to be employed in cases where great 
 celerity of movement is indispensable. 
 
 The effect of this change is to simplify the materiel of 
 field artillery, and to increase its ability to cope with 
 the rifle-musket, principally by the use of larger and 
 more powerful spherical case-shot. The principal ob- 
 jection to an increased calibrl for light field-guns, is the 
 increased weight of the ammunition, and the reduction 
 of the number of rounds that can be carried in the am- 
 munition chests. 
 
 MOUNTAIN AND PEAIEIE CANNON. 
 
 146. Mountain howitzer. Mountain artillery is de- 
 signed to operate in a country destitute of carriage-roads, 
 and inaccessible to field artillery. It must r therefore, be 
 light enough to be carried on pack-animals. 
 
 The piece used for moun- 
 tain service is a short, light 
 12-pdr. howitzer, weighing 
 Fig. 43. 220 lbs. See fig. 43. The 
 
 form of the chamber is cylindrical, and suited to a 
 charge of £ lb. of powder. The projectiles are shells 
 and case-shot. 
 
 It is discharged from a low two-wheel carriage, which 
 
184 CANNON. SIEGE AND GARRISON CANNON. 
 
 serves for transportation whenever the ground will per- 
 mit. When the piece is packed, the carriage is packed 
 on a separate animal. 
 
 The mountain howitzer is also employed for prairie 
 service, and in defending camps and frontier forts 
 against Indians, in which case it is mounted on a light 
 four-wheel carriage, called " the prairie carriage." 
 
 In the Mexican war, the mountain howitzer was found 
 useful, from the facility with which it could be carried 
 up steep ascents, and to the tops of flat-roofed houses, in 
 street-fighting. 
 
 SIEGE AND GARRISON CANNON. 
 
 Siege cannon are intended for attacking, and gar- 
 rison cannon for defending, inland fortifications and 
 the land fronts of sea-coast fortifications. 
 
 They comprise guns, howitzers, and mortars. 
 
 147. Siege guns. A siege gun is constructed to throw 
 a solid projectile with the highest practicable velocity, 
 in order to penetrate the masonry of revetments, and to 
 diminish the curvature of the projectile's flight, thereby 
 increasing its chances of hitting objects but slightly 
 raised from the ground* 
 
 Calibre. Although the 12-pdr. siege gun has been 
 found competent to breach good masonry, large calibres 
 will accomplish the object in a shorter time, and at a 
 greater distance. 
 
 The calibre, or weight, of siege guns must be limited 
 
 * The new rifle siege gun is made of cast iron, modelled after the new plan. 
 Its weight is 3,450 lbs., and the diameter of the bore is 4.5 inches. The length of 
 the bore is 26.66 diameters. The weight of the projectile is about 34 lbs., and the 
 charge varies from one-tenth to one-eighth the projectile. 
 
SIEGE MORTARS. 185 
 
 by the means of transporting them and their projectiles 
 to the scene of action. With horse-power over ordinary 
 roads, the 24-pdr. is the largest that can be employed 
 with convenience. With railroad or water communica- 
 tion, very large calibres may be brought into action, as 
 was the case at Sebastopol, where the English troops 
 used the 68-pdr. gun for breaching, and the 13-inch 
 mortar for vertical firing. 
 
 The siege guns are the 12-pdr., 18-pdr., and 24-pdr. 
 
 Charge. The usual charge of powder for breaching 
 masonry, is \ the weight of the solid shot This is the 
 greatest that can be fired without overstraining the gun 
 and its carriage ; and besides, as the resistance of the 
 air increases nearly with the square of the velocity, very 
 little additional useful effect would be produced on the 
 projectile by a greater charge. The usual charge for 
 range is J- the weight of the projectile. 
 
 Length. The mean length of bore of the three guns, 
 is 20 diameters. This length nearly secures the full 
 effect of the powder, and causes the muzzle to project 
 well into the embrasure of the battery, thereby pre- 
 venting the blast from injuring its cheeks. 
 
 Weight The mean weight is about 260 times the 
 weight of the shot. 
 
 Vertical field of fire. The construction of the car- 
 riage permits the gun to be elevated '12°, and depressed 
 4°. The natural angle of sight is 1° 30'. 
 
 Form. The form of siege guns is similar to that 
 shown in Hg. 26. 
 
 In the French service, siege cannon are made of 
 bronze ; but in most other services, including our own, 
 they are made of cast iron. 
 
186 
 
 CANNON. SIEGE AND GARRISON CANNON. 
 
 148. Siege howitzer. The siege howitzer is principally 
 employed for ricochet firing, and for the purpose of bat- 
 tering down the earth and fragments of masonry which 
 are left standing by the breaching-guns.* 
 
 Dimensions, &c. Its bore is 8 inches in diameter, and 
 nearly five diameters long, and it has a cylindrical 
 chamber capable of holding exactly 4 lbs. of powder. 
 As this piece is sometimes fired over the heads of men 
 
 in the advanced trenches, no 
 sabot or cartridge-block can be 
 placed between the shell and 
 powder ; hence, the surface join- 
 ing the chamber and bore, is 
 made spherical, to conform to the projectile. The form 
 of this piece is shown in fig. 44. 
 
 Trunnions. The size of the trunnions, and distance 
 between the rimbases, are made the same as in the 24- 
 pdr. gun, in order that it may fit the 24-pdr. carriage. 
 
 Hecess. The preponderance is regulated by remov- 
 ing a portion of the metal which surrounds the chamber. 
 The space thus left is called the recess. 
 
 149. Siege mortar*. The siege mortars comprise the 
 common mortar, the stone mortar, and the Coehorn mor- 
 
 Fig. 44. 
 
 tar. 
 
 Dimensions. The form of the common siege mortars, 
 is shown in fig. 45. There are two. sizes, 
 the 8-inch and 10-inch, called so from the 
 diameters of their bores. The length of 
 the bore is 1^ diameters, measured from the 
 Fig. 45. bottom of the projectile. The chambers 
 
 * The form of the new siege howitzer differs from the old one in having a per- 
 fectly smooth exterior. The chamber is elliptical in form. 
 
STONE-MORTAR. 187 
 
 are of the Gomer form, and capable of holding a charge 
 of powder j 7 the weight of the projectile.* 
 
 The weight of the piece is about twenty times that of 
 the shell. 
 
 Vertical field, of fire. The vertical field of fire lies 
 between 30° and 60° ; 45° is the angle at which all mor- 
 tars are usually fired, as this gives nearly the maximum 
 range for a given charge of powder. 
 
 Natural line of sight. The exterior form of siege 
 mortars is cylindrical ; consequently the natural line of 
 sight is parallel to the axis of the bore — a position of 
 great convenience in aiming. 
 
 Object. Siege mortars are used to attain those por- 
 tions of a work, by a vertical fire, which are defended 
 against the direct and ricochet fires of guns and howit- 
 zers, such as the covered way, the ditch, with its com- 
 munications, and the roofs of magazines, casemates, <fcc. 
 
 150. stone mortar. The stone mortar is employed in 
 siege operations to precipitate a large mass of small 
 stones, or hand-grenades, upon the heads of the enemy 
 in the advanced trenches, or, in like manner, to clear the 
 breach of its defenders preparatory to an assault.f 
 
 Dimensions, &c. The diameter of the bore is 16 inches, 
 and its length is about \\ times its diameter. Its cham- 
 ber is conical, and the charge of powder for 120 lbs. of 
 stones is 1^ lbs. ; and for fifteen 6-pdr. shells, it is 1 lb. 
 It is made of bronze, and mounted on a bed similar 
 to that for the 10-inch mortar. 
 
 * The form of all the mortars adopted in 1861 is shown in fig. 48. The chase is 
 cylindrical, the breech is hemispherical, and the trunnions are placed opposite to 
 the centre of gravity. The chamber is elliptical instead of the Gomer form. 
 
 f The stone mortar has been left out of the list of new cannon for the United 
 States, service, the common mortar being used instead. 
 
188 CANNON. SEA-COAST CANNON. 
 
 Spherical case-shot for mortars. It is proposed by 
 some military writers, to dispense with the stone mortar 
 in siege operations, and use, in its place, the 10-inch 
 mortar, with spherical case-shot ; as it has lately been 
 shown, in Belgium, that if a 10-inch mortar-shell be 
 filled with canister balls, 1.5 inches diameter, and be 
 exploded in its descent, about 50 feet from the ground, 
 the balls will have sufficient force to disable men. 
 
 151. Coeiiorn mortar. The Coehorn mortar, so called 
 after its inventor, General Coehorn, is a very small 
 bronze mortar, designed to throw a 24-pdr. shell to dis- 
 tances not exceeding 1,200 yards. Its weight is 164 lbs., 
 its maximum charge \ lb. powder, and it is mounted 
 on a wooden block furnished with handles, so that two 
 men can easily carry it from one part of a work to 
 another. 
 
 SEA-COAST CANNON. 
 
 152. Object. Sea-coast cannon are mounted in sea- 
 coast batteries for the defence of harbors, roadsteads, 
 &c, against vessels of war. Their efficiency depends on 
 size of calibre, combined with facility of manoeuvre, or 
 rapidity of fire. 
 
 As these cannon generally occupy permanent posi- 
 tions, the weight of the piece is not so serious an objec- 
 tion to an increase of calibre, as the weight of the pro- 
 jectile, which, if too great, renders the loading slow 
 and the fire less effective. It is found that shells of 10 
 or 11 inches diameter are quite as heavy as two men can 
 conveniently lift to the muzzle of the piece. The 8-in. 
 calibre is thought by some to combine power and rapid- 
 
PEOJECTILES. 189 
 
 ity of fire in a more favorable degree than any other ; 
 hence this calibre predominates in the present arma- 
 ment of sea-coast batteries. 
 
 153. L.arge cannon. Special cannon of very large 
 calibre are sometimes mounted in parts of a sea-coast 
 battery that command narrow and important channels. 
 The intention in such cases is, that the projectile 
 shall contain a large quantity of powder, a mine, in 
 fact, which shall destroy, by a single explosion, the ves- 
 sel against which it is directed. As the fire of such 
 large pieces is slow, and the speed of steam vessels very 
 great, it is evident that success depends on the certainty 
 with which a single shot strikes its object. 
 
 154. Projectiles. The most effective projectiles that 
 can be brought to bear on wooden ships, are shells and 
 hot-shot The destructive superiority of the former was 
 well attested in the Crimean war, and particularly in 
 the naval battle of Sinope, where the entire Turkish 
 fleet was destroyed by Russian shells, in about one 
 hour's time. 
 
 Modern mechanical skill has succeeded, to a certain 
 extent, however, in covering vessels of war with plates 
 of wrought iron, which are proof against shells, and 
 solid projectiles less than 8 inches calibre. It is said 
 that rifle-projectiles of less calibre, have power to pene- 
 trate through these coverings ; but they do not produce 
 the shattering effect of round-shot, which present a 
 larger surface, and, at short ranges, move with a higher 
 velocity. Should these mail-covered vessels come into 
 general use, it is very probable that the service of the 
 smaller sea-coast guns will eventually be dispensed with, 
 and pieces of very large calibre be substituted for them. 
 
190 CANNON. SEA-COAST CANNON. 
 
 155. Kinds of sea-coast cannon. Sea-coast cannon 
 comprise guns, columbiads, howitzers, and mortars. 
 
 The solid-shot pieces of the sea-coast service are, 
 the 32-pdr. and 42-pdr. guns, and the 8-inch, 10-inch, 
 and A 5-inch columbiads. 
 
 The form of the sea-coast guns in service, is shown in 
 fig. 26. Those to be made hereafter, will have no base- 
 ring, nor swell of muzzle. 
 
 Dimensions, dec, of the guns. The mean length of 
 bore is about 16 calibres. 
 
 The mean weight is about 200 times the solid shot. 
 
 The natural line of sight, being intercepted by the 
 reinforce, an artificial one is formed by affixing a sight 
 to the swell of the muzzle. 
 
 The charge of powder is ordinarily \ the weight of the 
 solid shot. 
 
 The projectiles employed are solid shot, shells, and 
 case-shot. 
 
 The maximum angle of elevation when mounted in 
 barbette is 11°, and in casemate it is 9°. 
 
 156. Columbiads. The columbiads are a species of 
 sea-coast cannon, which combine certain qualities of the 
 gun, howitzer, and mortar; in other words, they are 
 long, chambered pieces, capable of projecting solid shot 
 and shells, with heavy charges of powder, at high angles 
 of elevation, and are, therefore, equally suited to the 
 defence of narrow channels and distant roadsteads. 
 
 The columbiad was invented by the late Colonel 
 Bomford, and used in the war of 1812 for firing solid 
 shot. In 1844 the model was changed, by lengthening 
 the bore and increasing the weight of metal, to enable 
 
COLUMBIADS. 191 
 
 it to endure an increased charge of powder, or \ of the 
 weight of the solid shot. 
 
 Six years after this, it was discovered that the pieces 
 thus altered did not always possess the requisite length. 
 In 1858, they were degraded to the rank of shell-guns, 
 to be fired with diminished charges of powder, and 
 their places supplied with pieces of improved model. 
 The changes made in forming the new model, consisted 
 in giving greater thickness of metal in the prolongation 
 of the axis of the bore, which was done by diminishing 
 the length of the bore itself; in substituting a hemis- 
 pherical bottom to the bore, and removing the cylindri- 
 cal chamber ; in removing the swell of the muzzle and 
 base-ring ; and in rounding off the corner of the breech. 
 
 From the fact that all the trial pieces have success- 
 fully endured very severe tests, it is to be inferred that 
 the defects of the previous model arose from the pres- 
 ence of a cylindrical chamber, and a deficiency of metal 
 in the prolongation of the bore.* 
 
 Fig. 46. 
 
 * Six of the trial pieces (three 8-in. and three 10-in.), made at different foundries, 
 endured successfully upward of 1,000 service-rounds. Two 10-inch pieces (one cast 
 hollow, and the other cast solid) were fired 2,500 rounds with solid shot and 14 lbs. 
 of powder, and 1,632 rounds with 18 lbs of powder and solid shot. The only injury 
 sustained was the enlargement of the bore by the cutting action of the gas as it 
 passed over the shot. The enlargement of the bore of the solid-cast piece waa 
 much greater than in the hollow one. 
 
192 CANNON. SEA-COAST CANNON. 
 
 In 1860, the model proposed by Captain Rodman was 
 adopted for all sea-coast cannon. This model is shown 
 in fig. 46 ; it does not differ, however, in its essential 
 particulars from the model of 1858. 
 
 Dimensions. The following are the principal dimen- 
 sions, &c, of the new columbiads : 
 
 {8-inch, about 14 diameters. 
 10-inch, " 12 diameters. 
 15-inch, " 11 diameters. 
 ( 8-inch - - 8,500 lbs. 
 Weight, - - -j 10-inch - - 15,000 lbs. 
 ( 15-inch - - 50,000 lbs. 
 
 r 8-inch - ■ 10 lbs. 
 Charge, shot and shells, •< 10-inch • - 15 lbs. 
 
 ( 15-inch - - 40 lbs. 
 
 The great disparity in the diameters of the reinforce 
 and muzzle, renders it impracticable to affix an artificial 
 sight to the muzzle ; a small projection is therefore cast 
 on the upper side, between the trunnions, as a seat for 
 the front sight. 
 
 Vertical field of fire. The carriages permit the piece 
 to be depressed 5° and elevated 39°. 
 
 To facilitate pointing in so large a field of fire, a slot 
 is cut in the knob of the cascable, and a ratchet is 
 formed on the base of the breech to receive a " pawl," 
 attached to the head of the elevating screw. 
 
 If the difference of elevation be greater than the 
 length of a single notch of the ratchet, the piece is rap- 
 idly moved by a lever which passes through an opening 
 in the pawl. If the distance be less than the length of 
 a notch, the elevating screw is used. 
 
MORTAKS. 193 
 
 158. Howitzers.* A sea-coast howitzer is a cham- 
 bered piece, closely resembling a sea-coast gun in exte- 
 rior form. It is employed to throw large hollow pro- 
 jectiles with reduced charges of powder, chiefly in the 
 defence of narrow channels; 
 
 Dimensions, &c. The calibres are the 8 and 10 inch. 
 The diameter of the chamber and trunnions of the 8-inch 
 howitzer, is the same as the bore for the 32-pdr. gun, so 
 that these two pieces may fit the same kind of car- 
 riage. The 10-inch howitzer bears the same relation to 
 the 42-pdr. gun. 
 
 Mean weight, about 100 times the projectile. 
 
 Mean length of bore, about 10 calibres. 
 
 ~, /» 7 f 8-inch 8 lbs. 
 
 Charge of powder, \ w . nch ^ ^ 
 
 The howitzers, like the guns, have no naturau line of 
 sight. 
 
 The vertical field of fire is 16°: 11° above, and 5° be- 
 low the horizon. 
 
 Casemate howitzer. An iron piece similar in form to 
 the 24-pdr. field howitzer, is employed to flank the ditches 
 of permanent works, principally, with canister shot. This 
 piece is sometimes called a garrison howitzer. 
 
 154. Mortars. The sea-coast mortars 
 differ from the siege mortars in shape 
 (jig. 47) and weight. There are two cali- 
 bres, the 10 and 13 inch. Their weight 
 is about 60 times the weight of the 
 shell, and they are fired with a charge 
 equal to T V the weight of the shell. 
 
 Fig. 47. - 1 ' ° 
 
 * These pieces are now but little used. The 10-inch has been left out of the 
 revised armament of the forts altogether. 
 13 
 
194 
 
 CANNON. MANUFACTURE OF. 
 
 Length of lore for 10-inch, is 2± calibres. 
 " " 13-inch, is 2 " 
 
 159. Carronades. A carronade is a cannon, about 6 
 calibres long in the bore, and weighing about 65 times 
 the weight of the projectile. It was formerly much 
 used on ships of war and fortifications; and was de- 
 signed to throw a large projectile with small velocity, 
 for the purpose of smashing in, rather than penetrating 
 through the sides of a ship. Hence their original name 
 of " smashers." A carronade has no trunnions, but is 
 supported on its carriage by a stout bolt, which passes 
 through a loop cast on its under side. 
 
 S^Z^itt 
 
 MANUFACTURE OF CANNON. 
 
 160. Where made. Cannon for the United States' 
 service are made by private founders. The material 
 and product of the casting are under the supervision 
 of an ordnance officer, who receives the pieces only after 
 they have satisfied all the conditions imposed by the 
 regulations of the service. 
 
 The foundries for making cast-iron cannon are at 
 Coldspring, New York, South Boston, Massachusetts, 
 Pittsburgh, Pennsylvania, and Richmond and Bellona, 
 
 * The new 13-inch sea-coast mortar weighs 1*7.120 lbs., 
 and the length of the bore is about 2.7 diameters. It has 
 no preponderance — the axis of the trunnions passing 
 through the centre of gravity. The form is shown in fig. 
 48 ; a represents the handle, and b a ratchet, cast upon the 
 breech, to receive the point of a handspike for elevating 
 and depressing the piece. The weight of the projectile is 
 220 lbs., and the charge of powder is 20 lbs. 
 
 Fig. 48. 
 
MOULDING. 
 
 195 
 
 Virginia. The principal foundries for bronze cannon 
 are at South Boston and Chicopee, Massachusetts. 
 
 The manufacture of cannon is a valuable branch of 
 the work of these foundries, but the orders of the gov- 
 ernment are not sufficiently regular and extensive to 
 support them, and much other work is attended to ; but 
 the experience thereby obtained in the properties and 
 manner of treating metals, is useful in the improvement 
 of ordnance. 
 
 The several operations of manufacturing cannon are, 
 moulding, casting, cooling, and finishing. 
 
 161. Moulding. Moulding, in general terms, is the 
 process by which a cavity of the form of the gun is ob- 
 tained, by imbedding a wooden model in sand, and then 
 withdrawing it. 
 
 The wooden model is technically called 
 the u pattern /" and the sand is confined in 
 a box, which is divided into two or more 
 a parts, for convenience in withdrawing the 
 pattern. 
 
 The pattern of the piece to be cast, some- 
 what enlarged in its different dimensions, is 
 composed of several pieces of hard wood, 
 well seasoned, or, for greater durability, of 
 cast iron. The first piece of the model com- 
 prises the body of the piece from the base- 
 ring to the chase-ring; the swell of the 
 muzzle, and the sprue, or dead-head, are 
 formed of the second piece (fig. 49) ; the 
 breech, of the third ; and the trunnions, of 
 fourth and fifth pieces. See figs. 50 and 
 51. 
 
 Fig. 49. 
 

 196 CANNON. MANUFACTURE OF. 
 
 p^ The sprue, usually called "the head" is 
 
 an additional length given to the piece, for 
 
 the purpose of receiving the scoria of the 
 
 melted metal as it rises to the surface, and 
 
 furnishing the extra metal needed to feed 
 
 the shrinkage. Its weight also increases the density of 
 
 the lower portions of the piece. 
 
 The breech is slightly lengthened in 
 
 the direction of the knob of the cascable ? 
 
 to form a square projection by which the 
 
 piece can be held, when being turned and 
 Fig. 6i. bored 
 
 The best material for the mould is dry, hard, angu- 
 lar, and refractory sand, which must be moistened with 
 water in which strong clay has been stirred, to make it 
 sufficiently adhesive. When not sufficiently refractory, 
 the sand is vitrified by the high temperature of the 
 melted metal, and protuberances — not easily removed 
 — are formed on the casting. When not sufficiently 
 coarse and angular, the materials cannot be so united 
 as to preserve the form of the moulds. 
 
 The mould is formed in a case of cast- 
 iron, and termed the " box" or the "flask" 
 consisting of several pieces, each of which 
 has flanges perforated with holes for 
 
 Fig. 52. screw-bolts and nuts, to unite the parts 
 firmly. Fig. 52. 
 
 To form the mould, the pattern for the sprue and 
 muzzle, previously coated with pulverized charcoal, or 
 coke moistened with clay- water, to prevent adhesion, is 
 placed vertically on the ground, muzzle-part up, and 
 carefully surrounded by the corresponding parts of the 
 
MOULDING. 
 
 197 
 
 jacket. When properly adjusted, the sand, prepared 
 as above, is rammed around it. The model for the 
 
 Fig. 53. 
 
 body of the piece is then placed on the top of this, and 
 the corresponding parts of the jacket correctly secured 
 on, and filled in succession with the moulding composi- 
 tion. The patterns for the trunnions and rimbases are 
 bolted to the model of the piece, and when the sand is 
 rammed firmly around these, the bolts are withdrawn, 
 this part of the mould completed, and the end-plates 
 screwed on. Fig. 53. 
 
 After completing the mould for the body of the piece, 
 the model for the cascable is properly adjusted and the 
 mould completed. 
 
 Care is taken to cover each portion of the model with 
 the coke-wash mentioned above, and to sprinkle dry 
 sand upon the top of the mould in each piece of the 
 
198 CANNON. MANUFACTURE OF. 
 
 jacket, to prevent adhesion, so that the portions of the 
 mould may be separated. 
 
 In the body of the sand, a channel (b) for the intro- 
 duction of the metal, is formed in the same manner as 
 the mould cavity. It enters at the bottom of the mould, 
 to prevent the bottom from being injured by the falling 
 metal, and in an oblique direction, to give a circular 
 motion to the metal as it rises in the mould, and there- 
 by prevent the scoria from adhering to the sides. 
 
 When the mould is completed, the parts of the flask 
 are carefully taken apart, and the pieces of the model 
 withdrawn from the mould contained in them. If any 
 portions of the mould be injured in withdrawing the 
 model, they are repaired, and the interior of the mould 
 is covered with coke-wash ; after which the several parts 
 are placed in an oven to be gradually and perfectly 
 dried. When this is accomplished, the parts are car- 
 ried to a pit, where they are united and secured in a 
 vertical position, with the breech below. Any portion 
 of the sand broken off during the movements and ad- 
 justments, should be replaced, and the whole of the 
 interior covered with coke- wash. 
 
 The object of coke-wash is to prevent the sand from 
 adhering to the melted metal, which, when prepared, is 
 made to flow in at the entrance of the side-channel. As 
 the metal rises in the mould, a workman agitates it with 
 a long pine stick, to cause the scoria and other impu- 
 rities to rise to the surface, and bring them toward the 
 centre of the mould to prevent their entering the cavi- 
 ties for the trunnions. 
 
 162. Cooling. After the mould is placed properly in 
 the pit, it is usual to surround the box with sand, at 
 
BORING AND TURNING. 199 
 
 least as high as the trunnions of the gun. This is done 
 to prevent rapid cooling. With guns as heavy as 24- 
 pdrs., this sand is not removed for three days ; and as 
 the gun is heavier the time is prolonged, and is from 7 
 to 8 days for the 10-in. columbiad. At the proper time 
 this sand is removed, and the gun, still imbedded in the 
 box and sand of the mould proper, is hoisted out, and 
 the box taken off, and, when nearly cold, the gun cleaned 
 of the sand. For the method of cooling from the in- 
 terior,* see section 102. 
 
 163. Boring and turning. A cannon is bored by giv- 
 ing it a rotary motion around its axis, and causing a 
 rod armed with a cutter to press against the metal in 
 the proper direction. 
 
 The piece, supported in a rack, is carefully adjusted, 
 with its axis horizontal, and made to revolve on this 
 axis, by machinery attached to the square knob on the 
 cascable. After adjustment, the sprue-head is first to 
 be cut off. This is effected by placing a cutter opposite 
 the point at which the section is to be made, and press- 
 ing it against the metal whilst the piece is turning. 
 The head being cut off, and the cutter removed, the 
 boring is commenced by placing the boring-rod, armed 
 with the first cutter, called the piercer, in the prolon- 
 gation of the axis of the piece, and pressing it against 
 the metal. The piercer is used till it penetrates to the 
 bottom of the chamber, after which, a second cutter, or 
 reamer, is attached to the boring-rod ; and with this the 
 boring is made complete to the round part of the cham- 
 ber. The reamer is then removed, and its place sup- 
 
 * All cast-iron cannon for the land service are now required to be cast hollow, 
 and cooled from the interior, after the plan of Captain Rodman. 
 
200 CANNON. INSPECTION OF. 
 
 plied by the chamber-cutter, which gives the necessary 
 form and finish to that part of the bore. In hollow- 
 cast cannon the piercer is dispensed with. 
 
 Whilst the boring is taking place, the workman con- 
 trives to finish the turning of all the exterior of the 
 piece except the portion between the trunnions, which 
 is afterward planed off in another machine. 
 
 These operations having been completed, the piece is 
 placed in the trunnion-machine, and the trunnions are 
 turned down to the proper size. 
 
 Care is taken to make the trunnions of the same 
 diameter, and perfectly cylindrical. Their axes should 
 be in the same right line, perpendicular to the axis of 
 the piece, and intersecting it. 
 
 Boring the vent Whilst in the trunnion-lathe, the 
 axis of the piece is inclined to the horizon at the angle 
 the vent is to make with it. A drill is placed ver- 
 tically over the point where the vent is to be bored, 
 and pressed against the metal whilst a rotary motion is 
 given to it by hand or machinery. 
 
 The time required to finish a cannon, ready for in- 
 spection, depends upon its size, or from three to four 
 weeks for a 24-pdr. gun, and six weeks for an 11 -inch 
 gun. 
 
 INSPECTION OF CANNON. 
 
 164. inspecting instruments. These are used to verify 
 the dimensions of cannon, and to detect the presence 
 and measure the size of cavities in the metal. 
 
 The star-gauge is an instrument for measuring the 
 diameter of the bore at any point. 
 
 The cylinder-staff is used to measure the length of 
 
INSPECTION. 201 
 
 the bore. It is supported by a rest of a T form at the 
 muzzle, aud the extremity inserted in the gun is armed 
 with a measuring -point and guide-plate. 
 
 The cylinder gauge is a cylinder of cast iron, turned 
 to the exact or true diameter of the bore. When used, 
 it is attached to the end of the cylinder-staff. 
 
 The searcher consists of four flat springs turned up 
 at the end, and attached to a socket which is screwed 
 on to the end of the cylinder-staff. It is used to feel 
 for cavities in the surface of the bore. 
 
 The trunnion-gauge verifies the diameters of the trun- 
 nions and rimbases. 
 
 The trunnion-square is used to verify the position of 
 the trunnions with regard to the bore. 
 
 The trunnion-rule measures the distance of the trun- 
 nions from the rear of the base-ring. 
 
 Calipers, for measuring exterior diameters. 
 
 A standard-rule, for verifying other instruments. 
 
 The vent-gauges are two pointed pieces of steel wire, 
 0.005 inch greater and less than the true diameter of 
 the vent, to verify its size. 
 
 The .vent-searcher, is a hooked wire, used to detect 
 cavities in the vent. 
 
 A rammer-head, shaped to the .form of the bottom 
 of the bore, and furnished with a staff, is used to ascer- 
 tain the interior position of the vent. 
 
 A wooden rule to measure exterior lengths. 
 
 A mirror; a wax taper; bees-wax. 
 
 Hammer, sponge, and priming-wire. 
 
 Figure and letter stamps, to affix the required marks. 
 
 165. inspection. The objects of inspecting cannon 
 are to verify their dimensions, particularly those which 
 
202 CANNON. INSPECTION OF. 
 
 affect the accuracy of fire, and the relation of the piece 
 to its carriage, and to detect any defects of metal and 
 workmanship, that would be likely to impair their 
 strength and endurance. 
 
 Cannon presented for inspection and proof, are placed 
 on skids, for the convenience of turning and moving 
 them easily. They are first examined carefully on the 
 exterior, to ascertain whether there are any flaws or 
 cracks in the metal, whether they are finished as pre- 
 scribed, and to judge, as well as practicable, of the 
 quality of the metal. They must not be covered with 
 paint, lacquer, or any other composition. If it be ascer- 
 tained that an attempt has been made to conceal flaws 
 or cavities, by plugging them, the gun is rejected with- 
 out further examination. 
 
 After this preliminary examination, the inspector pro- 
 ceeds to verify the dimensions of the piece. 
 
 The interior of the bore is first examined by reflecting 
 the sun's rays into it from a mirror ; or by a lighted 
 wax-taper placed at the end of a long rod, and inserted 
 into the bore. The searcher is then introduced, and 
 pushed slowly to the bottom of the bore, and with- 
 drawn, turning it at the same time ; if one of the points 
 hangs, the position of the hole is marked on the outside 
 of the gun, by noticing its distance from the muzzle, 
 and its position in the bore ; the size and figure of the 
 cavity, are found by taking an impression of it in wax, 
 placed on the end of a hook. 
 
 The cylinder gauge, screwed on the staff, is then 
 pushed gently to the bottom of the cylindrical part of 
 the bore, and withdrawn ; it must go to the bottom, or 
 the bore is too small. 
 
INSPECTION. 203 
 
 The bore is then measured with the star-gauge. The 
 measurements should be made at intervals of \ inch in 
 the part of the bore occupied by the shot ; at intervals 
 of one inch in rear of the trunnions, and of about one 
 calibre from the trunnions to the muzzle. 
 
 The position of the trunnions, with regard to the axis 
 of the bore, and to each other, is next ascertained. 
 
 To verify the position of the axis of the trunnions, set 
 the trunnion-square on the trunnions, and see that the 
 lower edges of its branches touch them throughout their 
 whole length ; push the slide down till it touches the 
 surface of the piece, and secure it in that position by 
 the thumb-screw; turn the piece over, and apply the 
 trunnion-square to the opposite side, and if, when the 
 point of the slide touches the surface of the piece, the 
 lower edges of the branches rest on the trunnions, the 
 axis of the trunnions is in the same plane with the axis 
 of the bore ; if they do not touch the trunnions, their 
 axis is above the axis of the bore by half the space be- 
 tween ; and if the edges touch the trunnions, and the 
 point of the slide does not touch the surface of the 
 piece, their axis is below the axis of the bore. If the 
 alignment of the trunnions be accurate, the edges of the 
 trunnion-square will fit on them, when applied to dif- 
 ferent parts of their surface ; their diameter and cylin- 
 drical form, and the diameter of the rimbases, are veri- 
 fied with the trunnion-gauge. 
 
 To ascertain the length of the bore, screw the guide- 
 plate and measuringpoint on the cylinder-staff, and 
 push them to the bottom of the bore ; place a half 
 tompion in the muzzle, and rest the staff in its groove ; 
 
204 CANNON. INSPECTION OF. 
 
 apply a straight-edge to the face of the muzzle, and read 
 the length of the bore on the staff. 
 
 The exterior lengths are measured by the rule, or by 
 a profile, the accuracy of which is first verified. 
 
 The exterior diameters are measured with the cali- 
 pers and graduated rule. 
 
 The position of the interior orifice of the vent is found 
 from the mark on the rammer-head by the vent-gauge, 
 inserted in the vent while the rammer-head is held 
 against the bottom of the bore; two impressions are 
 taken. The position of the exterior orifice of the vent 
 is also verified. The vent is examined with the gauges, 
 and with the vent-searcher, to ascertain if there be any 
 cavities in it. 
 
 In mortars, the dimensions of the conical chambers 
 and the form of the breech, may be verified with pat- 
 terns made of plate-iron. After the powder-proof the 
 bore is washed and wiped clean, and the bore and 
 vent again examined, and the diameter of the bore 
 remeasured. 
 
 The results of each of the measurements and exami- 
 nations are noted on the inspection report against the 
 number of the gun. 
 
 166. Bronze cannon. That the finished bore of a 
 bronze piece may not be injured by the proof-charge, it 
 is bored out under size, from .04 to .05 inch, and, after 
 proof, reamed out to the true size. When the powder- 
 proof is finished, the bore should be cleaned and exam- 
 ined ; the vent should be stopped up with a greased 
 wooden plug, the muzzle raised, and the gun filled with 
 water, to which pressure should be applied to force it into 
 any cavities that exist ; or the water should be allowed 
 
POWDER-PKOOF. 205 
 
 to remain in the bore twenty-four hours. The bore must* 
 then be sponged dry and clean, and viewed with a mir- 
 ror or candle, to discover if any water oozes from cracks 
 or cavities, and also, if any enlargement has taken place. 
 The quantity that runs out of a crack or honey-comb 
 will indicate the extent of the defect ; and if it exceed 
 a few drops, the piece should be rejected, although the 
 measured depth of the cavity may not exceed the allow- 
 ance. 
 
 After the bore has been reamed out to its proper 
 size, its dimensions are again verified, and an examina- 
 tion of the bore and vent is made, to detect any defects 
 which may have been caused or developed by the proof. 
 
 Whitish spots show a separation of the tin from the 
 copper, and, if extensive, should condemn the piece. 
 
 A great variation from the t/rue weight, which the 
 dimensions do not account for, shows a defect in the 
 alloy. 
 
 Bronze cannon should be rejected for the following 
 sized cavities or honey-combs : 
 
 Exterior. Any hole or cavity 0.25 in. deep in front 
 of the trunnions, and 0.2 in. deep at or behind the 
 trunnions. 
 
 Interior. From the muzzle to the reinforce, any 
 cavity 0.15 deep. Any cavity from the reinforce to the 
 bottom of the bore. 
 
 In all other respects, the inspection of cast-iron and 
 bronze cannon are alike. 
 
 PROOF OF CANNON. 
 167. Powder-proof. Gunpowder for proving ordnance 
 
206 CANNON. PROOF OF. 
 
 should be of the best quality, ranging not less than 250 
 yds. by the eprouvette. The cartridge-hags are made of 
 woollen stuff or paper, the full diameter of the bore or 
 chamber. They are filled by weight, and if not filled at 
 the place where the guns are proved, each bag should 
 be enveloped in a paper cylinder and cap, marked with 
 the weight of powder and its proof-range. 
 
 The shot must be smooth, free from seams and other 
 inequalities that might injure the bore of the piece, and 
 they must be of the true diameter given in the tables. 
 
 168. iron cannon. Guns and howitzers are laid with 
 the muzzle resting on a block of wood, and the breech 
 on the ground or on a plank, giving the bore a small 
 elevation. 
 
 Mortars are mounted on strong wooden frames or 
 beds, at an elevation of 45°, supported by the trunnions. 
 
 Guns, dec. Gruns, howitzers and columbiads, are fired 
 three times, with a solid shot and a charge of powder 
 somewhat greater than the service charge. 
 
 In proving new guns, compound shot, or a cylinder 
 with hemispherical ends, of the true diameter of the 
 shot, and equal in weight to the two shot, shall be used 
 instead of them. 
 
 Should any of the guns proved at one time, fail to 
 sustain the above proof, the remainder shall be rejected, 
 if made of the same metal and treated in the same 
 manner. 
 
 Mortars are proved in the same manner as the above, 
 with the exception that shells filled with sand are used 
 in place of shot. 
 
 169. Bronze eannon are fired three times with solid 
 shot and a charge of powder one-third the weight of the 
 
INJUEIES. 207 
 
 shot. If the piece has been in service, or if it be new, 
 and its bore be of the true size, the shot should be 
 wrapped in cloth or strong paper, to save the bore as 
 much as possible from injury. 
 
 170. inspection marks.* All cannon are required to 
 be weighed, and to be marked as follows, viz. : the num- 
 ber of the gun, the initials of the inspectors name, on 
 the face of the muzzle — the numbers, in a separate series, 
 for each kind and calibre at each foundry ; the initial 
 letters of the name of the founder and the foundry, on 
 the end of the right trunnion; the year of fabrication, 
 on the end of the left trunnion ; the foundry number, 
 on the end of the right rimbase, above the trunnion; 
 the weight of the piece in pounds, on the base of the 
 breech ; the letters U. S., on the upper surface of the 
 piece, near the end of the reinforce. 
 
 The natural line of sight, when the axis of the trun- 
 nions is horizontal, should be marked on the base-ring 
 and on the swell of the muzzle, whilst the piece is in 
 the trunnion-lathe. 
 
 Cannon rejected on inspection, are marked XC, on the 
 face of the muzzle ; if condemned for erroneous dimen- 
 sions which cannot be remedied, add XD ; if by powder- 
 proof, XP ; if by water-proof, XW. 
 
 INJURIES CAUSED BY SERVICE. 
 
 171. External. The only external injury of import- 
 ance, is the bending of the trunnions of bronze cannon 
 by long firing. 
 
 * In cannon modelled in 1861, all the marks are placed on the face of the muzzle. 
 
208 CANNON. INJUKIES. 
 
 172. internal. Internal injuries arise from the sepa- 
 rate actions of the powder and the projectile. They in- 
 crease in extent with the calibre, whatever may be the 
 nature of the piece, but are modified by the material of 
 which it is made. 
 
 Injuries from the powder. The injuries from the pow- 
 der generally occur in rear of the projectile. They are, 
 
 1st. The enlargement of that portion of the bore 
 which contains the powder, arising from the compression 
 of the metal. This injury is more marked when a sabot 
 or wad is placed between the powder and projectile, 
 and is greatest in a vertical direction. 
 
 2d. Cavities, produced by the melting away of a 
 portion of the metal by the heat of combustion of the 
 charge. 
 
 3d. Cracks, arising from the tearing asunder of the 
 particles of the metal at the surface of the bore. At 
 first a crack of this kind is scarcely perceptible, but it 
 is increased by continued firing until it extends com- 
 pletely through the side of the piece. It generally com- 
 mences at the junction of the chamber with the bore, 
 as this portion is less supported than others. 
 
 4th. Furrows, produced by the erosive action of the 
 inflamed gases. This injury is most apparent where the 
 current of the gas is most rapid, or at the inner orifice 
 of the vent, and on the surface of the bore, immediately 
 over the seat of the projectile. 
 
 The wear of the vents of bronze cannon is obviated 
 by inserting a copper vent-piece (par. 84). The effect of 
 continuous firing on the vents of iron cannon is to pro- 
 duce a uniform enlargement of the inner orifice, and to 
 seriously weaken the piece. The appearance of a vent 
 
INJURIES. 209 
 
 thus enlarged, is irregular and angular, with its greatest 
 diameter in the direction of the axis of the bore. 
 
 To obviate the serious consequences that result from 
 this injury, Captain Dahlgren has placed in his naval 
 guns two vents, each a short distance from, and on op- 
 posite sides of, the vertical plane passing through the 
 axis of the piece. One of them is filled with melted 
 zinc; the other is used until it becomes so much en- 
 larged as to endanger the safety of the piece ; it is then 
 filled with zinc, and the first one is opened. 
 
 Injuries from the projectile. The injuries arising 
 from the action of the projectile occur around the pro- 
 jectile, and in front of it. They are, 
 
 1st. The lodgement. This is an indentation in the 
 lower side of the bore, produced by the pressure upon 
 the ball by the escape of the gas through the windage, 
 before the ball has moved from its seat. The elasticity 
 of the metal, and the burr, or crowding up, of the metal 
 in front of the projectile, cause it to rebound, and being 
 carried forward by the force of the charge, to strike 
 against the upper side of the bore, a short distance in 
 front of the trunnions. From this it is reflected against 
 the bottom, and re-reflected against the top of the bore, 
 and so on until it leaves the piece. 
 
 The first indentation is called the lodgement ; the 
 others, enlargements. In pieces of ordinary length, 
 there are generally three enlargements, when this injury 
 first makes its appearance, but their number is increased 
 as the lodgement is deepened and the angle of inci- 
 dence increased. Brass pieces are considered unservice- 
 able when the depth of the lodgement is .18 in., and 
 the depth of an enlargement is .16 in. 
 
 14 
 
210 CANNON. INJURIES. 
 
 The effect of this bounding motion, is to alternately 
 raise and depress the piece in its trunnion-beds, and to 
 diminish the accuracy of fire, until finally, the piece 
 becomes unfit for service. 
 
 It is principally from this injury that bronze guns 
 become unserviceable. Mortars and howitzers are not 
 much affected by it. 
 
 The principal means used to obviate this injury, are 
 to wrap the projectile with cloth or paper (as the cyl- 
 inder cap of the cartridge used with field-guns), and .to 
 shift the seat of the projectile. The latter may be done 
 by a wad, or lengthened sabot, or by reducing the diam- 
 eter and increasing the length of the cartridge. The 
 last of these methods is considered the most practical 
 as well as the most effective ; and it has the additional 
 advantage of diminishing the strain on the bore, by 
 increasing the space in which the charge expands before 
 the ball is moved. 
 
 The French bronze siege-guns, which formerly were 
 rendered unserviceable in 600 service-rounds, now en- 
 dure, by this method, 2,500 service-rounds. 
 
 2d. Scratches, or furrows made upon the surface of 
 the bore by rough projectiles, or by case-shot. This is 
 not a serious injury. 
 
 3d. Cuts, made by the fragments of projectiles which 
 break in the bore. 
 
 4th. Enlargement of the bore, arising from the com- 
 pression of the metal by the powder. 
 
 5th. Enlargement of the muzzle, arising from the 
 forcing outward of the metal by the striking of the 
 projectile against the side of the bore, as it leaves the 
 
INJURIES. 211 
 
 piece. By this action, the shape of the muzzle is elon- 
 gated in a vertical direction. 
 
 6th. Cracks on the exterior. These are formed by 
 the compression of the metal within, generally at the 
 chase, where the metal is thinnest. This portion of 
 a bronze gun is the first to give way by long firing, 
 whereas, cast-iron cannon are burst in rear of the trun- 
 nion, and the fracture passes through the vent, if it be 
 much enlarged. 
 
 Cast-iron cannon. The principal injuries to which 
 cast-iron cannon are liable are, the enlargement of the 
 vent by service, and the change in the size and form of 
 the bore, and the enlargement of cavities, by rust. 
 
 It has been seen that the strength of cast-iron cannon 
 is diminished by repeated firing ; there is a limit, there- 
 fore, beyond which they should not be used. This 
 limit has not been fixed by regulation for American 
 cannon; but it is inferred from the test standard (sec. 
 Ill), that no cast-iron piece will be called upon to en- 
 dure more than 1,000 service-rounds, except in case of 
 emergency. 
 
 The number of times which an iron piece has been 
 fired may be approximately determined by the size of 
 the bore and the vent. The first is taken by the " star- 
 gauge," and the second, by taking an impression in wax. 
 
212 ARTILLEEY CARRIAGES. 
 
 CHAPTER IV. 
 ARTILLERY CARRIAGES. 
 
 173. Classification. Artillery carriages may be di- 
 vided into two classes, viz., those employed for the 
 immediate service and transportation of cannon, as gun- 
 carriages and mortar-beds, and those -employed for the 
 transportation of ammunition, implements, and materials 
 for repairs, as caissons*, mortar-wagons, forges, and bat- 
 tery-wagons. 
 
 The points to be considered in the construction of all 
 carriages are those which relate to the draught, those 
 which refer to the load to be transported, and (in the 
 particular case of artillery carriages) those which relate 
 to the service of the piece. 
 
 Under the .first head will be considered the liorse as 
 a motive power, the harness and its mode of attachment 
 to the carriage, and the wheel, in its relation to fric- 
 tion, &c. 
 
 The horse transports his load in two distinct ways : 
 1st, as sl pack-horse ; 2d, as a draught-horse. 
 
 IT 4. Pack-horse. The load, gait, journey, forage, 
 intervals of rest, &c, of a work-horse should be so pro- 
 portioned that he will be no more fatigued one day than 
 another. 
 
 It has been determined by experience, that a pack- 
 horse, travelling at a walk, over a good road, can carry 
 
DRAUGHT-HORSE. 213 
 
 from 220 to 300 lbs., 30 miles in 10 hours ; or if lie 
 moves at a trot, 175 lbs. over the same distance. 
 
 The daily work of a pack-horse is equal to that of 
 five men, under the same circumstances. If the road be 
 hilly the advantage will be in favor of the men. 
 
 The above data suppose that the animal is regularly 
 fed on the service-ration. If he be fed on grass alone, 
 an allowance must be made for its quality and abun- 
 dance. 
 
 In some respects the mule is a superior pack-animal 
 to the horse. His peculiar build gives him, in propor- 
 tion to his weight, a greater j)ower to transport a load 
 on his back ; besides this, the mule eats less than the 
 horse, and is more sure-footed. 
 
 175. »raugiit-iior§e. The force exerted by a draught- 
 horse may be divided into two parts, viz., that which 
 overcomes the inertia and friction of the carriage and 
 sets it in motion, and that which is necessary to over- 
 come the resistances which recur along its path. The 
 first, being of momentary duration, may approximate 
 the utmost strength of the animal ; its intensity should 
 be known in order to give the necessary strength to the 
 harness. 
 
 If Q represent the mean force (in lbs.) exerted by a 
 horse, in a unit of time, in drawing a load over a road, 
 the length of which is Z, Ql represents the quantity of 
 work performed. The direction of the force is taken 
 parallel to the plane along which the load moves. If it 
 make an angle, a, with this plane, the work will be de- 
 composed into two components, Ql cos. a, which is par- 
 allel to the plane, and Ql sin. #, which is perpendicular 
 to it : the latter transfers a portion of the load from 
 
214 
 
 AETILLERY CARRIAGES. 
 
 the ground to the horse's shoulders, thereby increasing 
 his friction, and to a certain extent the power of trac- 
 tion. 
 
 Momentary effort. Careful experiments have been 
 made in France to determine the proportion of those two 
 components most favorable to the exercise of the horse's 
 power. It was found that the most suitable angle for 
 the traces of an unloaded horse, with the ground, was 
 from 10° to 12° ; and for a horse that carried his driver, 
 from 6° to 1° ; or, in other words, a draught-horse should 
 carry \ of his load on his back. 
 
 Continuous effort. The relation between the weight 
 of a loaded carriage and the force to be expended by the 
 horse to keep it in motion, depends upon so many cir- 
 cumstances that it is impossible to give a general ex- 
 pression for its determination. It can only be deter- 
 mined by direct experiment in each particular case. 
 
 NATURE OF 
 CARRIAGE. 
 
 NATURE OP ROAD. 
 
 GAIT. 
 
 VALUE OF 
 
 m 
 
 Spring carriages. 
 
 Pavement in good con- 
 dition. 
 
 Slow walk. 
 Fast walk. 
 Slow trot. 
 Fast trot. 
 
 iV 
 
 JL 
 
 36 
 
 1 
 24 
 
 1 a 
 
 All gaits. 
 
 1 
 23 
 
 Slightly sandy. 
 Very sandy. 
 
 All gaits. 
 
 1 
 
 2 2 
 
 V 
 
 1 
 
 Field artillery car- 
 riages. 
 
 Turf. 
 
 Newly ploughed up and 
 dug over. 
 
 Walk. 
 
 u 
 
 JL 
 
 2 2 
 
 rV 
 
 The foregoing table embraces the results of some ex- 
 
HARNESS. 215 
 
 periments on this point, in which m is the ratio of the 
 weight of the loaded carriage and the force of traction ; 
 whence it is seen that a carriage moving over a rough 
 or paved road, meets with a resistance which increases 
 rapidly with its velocity ; but over a smooth or sandy 
 road, the resistance to draught is independent of the 
 velocity. 
 
 The load allotted to an artillery horse is less than 
 that usually drawn by a horse of commerce, for the 
 reason that allowance must be made for bad roads, bad 
 forage, rapid movements, and forced marches. They are 
 as follows : 
 
 Light artillery horse, 700 lbs., including carriage. 
 Heavy field artillery, 850 " " u 
 
 Siege artillery, 1,000 " " " 
 
 The above is based on the rapidity of movement re- 
 quired in the different services. 
 
 An ordinary draught-horse can draw 1,600 lbs. 23 
 miles in a day. 
 
 Usually, a horse can draw 7 times as much as he can 
 carry ; hence, all material of war should be transported 
 on carriages, if practicable. 
 
 HARNESS. 
 
 176. Requirements The best method of attaching 
 horses to a carriage is that which enables each one to 
 perform a given amount of work with the least fatigue ; 
 or, in other words, no horse should be restrained by the 
 
216 ARTILLERY CARRIAGES. 
 
 efforts of another, and the direction of the traces should 
 be most favorable for draught. 
 
 Besides these conditions, artillery-harness should be 
 so constructed that it can be put on and taken off 
 promptly, by night as well as by day, in all states of 
 the weather, and in cases of danger, when the drivers 
 would be liable to lose their presence of mind. The 
 fall of one horse should not interfere with another ; and 
 a dead or wounded horse should be easily replaced, 
 whatever may be his position in the team. The ab- 
 sence of some of the horses, the unhitching or cutting 
 of some of the traces should not arrest the movement 
 of the carriage. Finally, the drivers, who are mounted 
 for the better command of their horses, should not be 
 incommoded by the pole of the carriage. 
 
 177. ]*iode§ of attachment. There are three general 
 modes of attaching horses to artillery carriages, and 
 upon the employment of any one of which depends the 
 construction of the harness. 
 
 In the first method the wheel-horse is placed between 
 two shafts, by which he guides and regulates the motion 
 of the carriage. 
 
 The horses may be arranged in single or double file. 
 The former arrangement was much in vogue in artillery 
 before the days of Gribeauval, but at present is only 
 employed in the mountain service. 
 
 This method has the merit of being well suited for 
 drawing heavy loads over smooth roads, but is not 
 adapted to rapid movements over ordinary roads, as 
 much of the tractile force is lost by the continued 
 change in the line of traction incident to long columns. 
 The force thus lost is expended in a great measure on 
 
PRESENT METHOD. 217 
 
 the shaft-horse, which, by constant fatigue, is soon ren- 
 dered unserviceable. 
 
 In the English light artillery the horses are arranged 
 in double file, 'the off wheel-horse being placed in shafts. 
 
 178. Gribeauvai'i method. In the second method, the 
 horses are arranged in double file — a wheel-horse being 
 placed on each side of the pole, which is attached to 
 the front axle-tree. 
 
 The pole is supported and kept steady by the pressure 
 of the body of the carriage on the sweep-bar, which pro- 
 jects in rear of the front axle-tree. The leading horses 
 are attached to the swing-tree, which is fastened to the 
 pole, and the wheel-horses are attached to a movable 
 splinter-bar, the centre of which is in the axis of the 
 pole. The object of making a splinter-bar movable is 
 to equalize the draught between two horses, one of 
 which works more freely than the other. 
 
 This system of attachment is used in most carriages 
 of commerce, and so far as the draught alone is con- 
 cerned, is superior to all others. It is also used in all 
 siege-carriages, and baggage- wagons of the military 
 service, except that in the former the splinter-bar is 
 fixed. 
 
 179. Pre§ent method. In field-carriages of late pat- 
 tern the siveep-bar is omitted, to facilitate attaching and 
 detaching the rear carnage in time of action ; and the 
 pole is supported by two yokes attached to the collars 
 of the horses. The wheel-horses are attached to a fixed 
 splinter-bar, which is strong and simple in its construc- 
 tion ; and the traces of the leading horses are attached 
 directly to those in the rear, giving a continuous line of 
 traction, communicating directly with the carriage. This 
 
218 
 
 ARTILLERY CARRIAGES. 
 
 method of attaching artillery-horses in line is extremely 
 simple, and at the same time it fulfils nearly all the 
 conditions requisite for artillery harness. Its principal 
 defect, however, is that, from the want of a sweep-bar 
 the weight of the carriage-pole is borne on the necks of 
 the wheel-horses, which is a serious inconvenience in 
 long marches. 
 
 How composed. Artillery harness is composed of the 
 head-gear, to guide and hold the horse ; the saddle, for 
 the transportation of the driver and his valise; the 
 draught-harness, which enables the horse to move the 
 carriage forward ; and the breeching, which enables him 
 to hold it back, stop it, or move it to the rear. 
 
 Head-gear. The head-gear is composed of the bridle, 
 by which the horse is guided, and the halter, by which 
 he is held when detached from the carriage. 
 
 Fig. 54. 
 
 Saddle. A riding-saddle (2, fig. 54) is placed on 
 each near horse, for the driver, and a valise-saddle on 
 each off horse. 
 
 Draught-harness. This is composed of a collar (1), 
 which serves as a cushion for the hames to rest upon, 
 without injuring the horse's shoulders. The hames are 
 two curved pieces of iron, which embrace the collar, and 
 
PEESEEVATION. 219 
 
 are fastened together at the top and bottom. To each 
 hame is attached a stout leather tug (5), which termi- 
 nates in an iron ring, to which the trace is attached. 
 The traces are stout leather straps, terminated at each 
 end with chains, and are used in pulling the carriage. 
 The chain at the rear extremity is used to shorten or 
 lengthen the trace at will. The forward chain plays 
 back and forth in the ring of the tug, which makes the 
 wheel-horse independent of the leading horses. The 
 pole-yoke (8) is supported by a chain attached to the 
 hame-clasp, and a ring which slides along the yoke. 
 The branches of the yoke are jointed to a collar near 
 the extremity of the pole, in such manner that they can 
 only play in a plane passing through the axis of the 
 pole. This arrangement enables the horse to keep the 
 pole steady without constraining his motion. 
 
 Breeching. The breeching is composed of the breech- 
 strap (6), breast-strap, and hip-strap (10). The breech- 
 strap and breast-strap united, completely encircle the 
 horse. They are attached to the pole-strap (7) by an 
 iron loop. The hip-strap sustains the breeching as it 
 passes around the horse's flanks. 
 
 The harness of the leading horses has no breeching ; 
 in all other respects, it is similar to that of the wheel- 
 horses. 
 
 180. Preservation, &c. A storehouse for harness 
 should be well ventilated — not too dry, but free from 
 dampness. The different articles should be arranged in 
 bundles, according to kind and class, without touching 
 the wall or each other. Harness should be examined 
 four times a year, at least. The leather parts are 
 brushed and greased with neatsfoot oil as often as con- 
 
220 ARTILLERY CARRIAGES. 
 
 dition requires ; if they have a reddish hue, add a little 
 lampblack to the oil. The hair side of the leather 
 should be wet with a sponge dipped in warm water, 
 and the oil applied before the surface is dry. The iron 
 parts which are not japanned should be covered with 
 tallow. 
 
 WHEEL. 
 
 181. Nomenclature. All artillery carriage wheels 
 are similarly constructed; they differ, however, in the 
 size and strength of certain parts, depending on the size 
 of the carriage to which they are attached. 
 
 The principal parts are (Hg. 55), the nave 
 (2), the nave-bands (3), the nave-box (1), the 
 spokes (4), the felloes (5), and the tire (6). 
 
 The nave constitutes the central portion 
 of the wheel, and distributes the pressure of 
 the axle-arm to the spokes. It is generally 
 made of a single piece of wood, and strength- 
 ened by four iron bands called the nave- 
 bands. It is also pierced with a conical hole Fig - 55 - 
 for the axle-arm ; and to diminish wear and friction, it 
 is lined with a box of brass or cast-iron, called the nave- 
 box. The spokes serve to transmit the pressure of the 
 load to the rim of the wheel. In all artillery carriages 
 there are seven felloes and fourteen spokes. The felloes 
 are the wooden segments which form the rim, and are 
 joined together at their ends by wooden pins, or 
 dowels. The tire is a strong band of iron, shrunk 
 tightly around the felloes, to hold them together, and 
 protect the rim from wearing away by contact with the 
 ground. 
 
FEICTION. 221 
 
 182. Dish. Tlie spokes are fastened to the nave and 
 felloes by means of mortices and tenons, and in a direc- 
 tion oblique to the axis of the nave. Thus situated, 
 they constitute the elements of a conical surface, which 
 is called the dish — the principal object of which is to 
 give stiffness to the wheel, and enable it to offer greater 
 resistance to the lateral vibrations of the load, in pass- 
 ing over uneven ground. 
 
 The height of the dish will therefore depend on the 
 nature of the ground ; and in artillery carriages, which 
 are required to pass over a great variety of ground, it 
 is about two inches. 
 
 The dish gives elasticity to the wheel, and increases 
 its durability ; it permits the . axle-tree to be made 
 shorter, and therefore stronger ; it relieves the linch-pin 
 of a certain amount of pressure, which it transfers to 
 the shoulder- washer — the wheel is, therefore, less liable 
 to come off in travelling ; for a given length of axle-tree, 
 it allows a greater width of carriage-body ; and finally, 
 it throws the mud clear of the carriage. 
 
 The stiffness of a carriage- wheel may be increased by 
 placing every alternate mortice in the nave nearer the 
 shoulder of the axle-tree : this gives one half of the 
 spokes a greater dish than the other half. This plan, 
 however, does not answer for artillery carriages. 
 
 183. Friction. The object of a carriage-wheel is to 
 diminish the resistance opposed to draught, by trans- 
 ferring the friction from the ground to the axle-arm. 
 
 When a carriage is at rest, the lowest element of the 
 axle-arm is supported on the bottom of the nave-box. 
 To set the carriage in motion, the friction along the 
 elements of contact, arising from the weight of the car- 
 
222 ARTILLERY CARRIAGES. 
 
 riage, must be overcome, and the axle-arm must rise in 
 the nave-box as though it were moving up an inclined 
 plane tangent to the surface of the box. When this is 
 done, the weight of the loaded axle-arm causes the 
 wheel to revolve around the point of contact with the 
 ground, and the constant repetition of these conditions 
 produces motion. 
 
 Let P be the weight resting on the element of con- 
 tact; p the weight of the wheel; Xthe force necessary 
 to produce motion ; r the radius of the box; and/ the 
 co-efficient of friction between the arm and box. When 
 the wheel is well greased, this co-efficient is about 0.180. 
 
 To determine the force acting parallel to the ground 
 which will move the wheel, we have the resultant of 
 P and JT, equal to VP 2 -\-X*, and the friction arising 
 from it, equal to fVP 2 +X 2 . The pressure on the 
 ground is P-\-p; and if the wheel slips, the friction on 
 the ground will be F(P-\-p), F being the co-efficient 
 of friction. The points of these resistances, being at 
 the distances r and R from the centre of rotation, re- 
 spectively, they will counteract each other when 
 
 rf\/P 2 ~+JP=FR(P+p). 
 
 If the wheel turns, there is no slipping on the ground, 
 and 
 
 frfP*+X'<FIl(F+p), 
 
 from which it results that 
 
 Vpi+JT _ fr p 
 R VR 2 -f 2 ^ 
 
 So long as the wheel turns, the draught is not af- 
 fected by the friction on the ground, since the value of 
 X is independent of F; but if F becomes so small 
 
ROLLING-FRICTION. 223 
 
 that frvP 2 -\-X 2 becomes equal to or greater than 
 FM{P-\-p), the wheel will no longer turn, but slide as 
 the runner of a sled. This occurs on ice, or when the 
 wheels are locked; in which case the draught is pro- 
 portional to the friction on the ground. 
 
 From the expression for the value of X we see that 
 the resistance which a wheel offers to motion, increases 
 with the radius of the axle-arm, and decreases with the 
 radius of the wheel. 
 
 When the radii are nearly equal, the wheel becomes 
 a roller — a machine much used in modifying the fric- 
 tion of fortress carriages. 
 
 184. Rolling-friction. In the theoretical expression 
 of the force necessary to move a wheel, rolling-friction 
 has been omitted, as it is very small when the wheel is 
 inelastic, and the ground is very hard. The experi- 
 ments of Coulomb show that this kind of friction does 
 not increase the draught of an artillery carriage more 
 than 2 j- lbs. 
 
 When the wheel penetrates the ground, it will expe- 
 rience the same resistance as though it were moving 
 upon an inclined plane whose inclination increases with 
 the depth of penetration; and Edge worth found, in ex- 
 periments with two-horse carriages, that the force neces- 
 sary to move a wheel is six times greater than the the- 
 oretical force. This difference arises from the compres- 
 sibility of the soil, and the flexibility of the wheel. On 
 railroads, where the wheels and track are made of iron, 
 the actual and the theoretical draught are very nearly 
 the same ; and on the best roads it is about five times 
 more than on a railroad. 
 
 The depth of the rut, or track, made by a wheel, may 
 
224 ARTILLERY CARRIAGES. 
 
 be reduced by making the felloes broader ; this increase 
 will also cause a wheel to pass more easily over rough 
 ground. Rumford found by experiment that a 7 -inch 
 felloe required one-tenth more tractile force than one of 
 12 inches breadth, on a pavement, one-twelfth on a hard 
 road, and one-seventh on a sandy road. 
 
 185. Size of wheel. The saving of tractile force arising 
 from increasing the diameter of a carriage-wheel, is lim- 
 ited by the height of the horse, for if the centre of the 
 nave be higher than his shoulders — the point at which 
 the traces are attached — the line of traction will be in- 
 clined downward, and if he be moving up hill, or on 
 level ground, the vertical component of the tractile force 
 will increase the friction of the wheel, and diminish the 
 hold of the horse upon the ground. If he be moving 
 down hill, the same cause diminishes the friction of the 
 wheels, and consequently increases the difficulty of hold- 
 ing back. 
 
 Large wheels surmount ordinary obstacles more 
 easily than small ones, and . penetrate less into yielding 
 ground. 
 
 Weight of wheel. The wheels of gun-carriages should 
 be as light as possible, to prevent the axle-tree from 
 being bent in the first instant of the recoil, before their 
 inertia is overcome. 
 
 186. Kinds. To make it practicable to replace broken 
 wheels in the field, there should be as few kinds as pos- 
 sible for each service. In the field service there are two 
 sizes, called Nos. 1 and 2 ; and in the siege service but 
 one. The No. 2 wheel is stronger than No. 1, and is 
 used on the heaviest carriages. Both wheels, however, 
 have the same height (58 inches) and the same size of 
 
GUN-CARRIAGES. 225 
 
 nave-box, that they may be interchanged if necessary. 
 The siege wheel is 60 inches in diameter. 
 
 GUN-CARKIAGES. 
 
 187. General conditions. Gun-carriages are designed 
 to transport cannon from one point to another, and to 
 support them when fired. A suitable gun-carriage, 
 therefore, should allow the piece to be easily and 
 promptly pointed in the direction of its object; it 
 should be capable of being served by the smallest num- 
 ber of men, and transported with the greatest ease ; its 
 recoil, under fire, should be restrained within suitable 
 limits; and it should have sufficient strength and sta- 
 bility to resist overturn or injury from the greatest 
 service-charge. 
 
 The injury to the carriage arising from the recoil of 
 the piece, increases with the square of the velocity of 
 the recoil, which is dependent on the relation between 
 the weight of the carriage and the weight of the piece. 
 Generally speaking, the piece should be heavier than 
 the carriage. 
 
 188. Principal parts. Artillery carriages, like the 
 cannon which they support, are classified into field, 
 mountain, prairie, -siege, and sea-coast carriages. The 
 sea-coast carriages not being required for the transporta- 
 tion of their pieces, differ materially from the others in 
 their construction. 
 
 The principal parts of all other art llery carriages (fig. 
 i)6) are, the stock (1), the cheeks (2), the axle-tree (3), 
 the wheels (4), and the elevating screw (5). 
 
 The stock. The stock is a long rectangular piece of 
 
 15 
 
226 
 
 ARTILLERY CARRIAGES. GUN-CARRIAGES. 
 
 Fig. 56. 
 
 wood, the front end of which is attached to the axle- 
 tree, while the rear end rests npon the ground when the 
 piece is fired, to form, with the wheels, the three neces- 
 sary points of support. 
 
 When the carriage is in travelling condition, the stock 
 connects the front and rear wheels, and constitutes the 
 basis of the carriage-body. It is employed as a point 
 of support for the elevating screw, and to give, with the 
 assistance of a handspike inserted in its rear end, the 
 proper direction to the piece in aiming. 
 
 The cheeks. The cheeks are two thin but strong 
 pieces of wood, attached, one to each side of the head- of 
 the stock, to sustain the trunnions of the piece. The 
 notches into which the trunnions fit are lined with iron 
 plates, called the trunnion-bed plates. 
 
 The axle-tree. The axle-tree is composed of two parts 
 — the axle-tree proper, which is made of wrought iron, 
 and the wooden body, which encases all the iron portion 
 between the wheels, in such a manner as to distribute 
 the pressure of the head of the stock and cheeks uniform- 
 ly over it, and prevent it from being bent by the shock 
 of the discharge. 
 
 The extremities of the axle-tree, or arms, are accurate- 
 ly turned to a conical shape to fit the nave-boxes. The 
 
GUN-CARRIAGES. 227 
 
 conical shape gives lightness and stiffness to the arm, 
 and facilitates putting on the wheel. The lower ele- 
 ments of the arms being horizontal, the pressure is nor- 
 mal to the surface of the arm, and there is no undue 
 tendency of the wheel to slip off. 
 
 The wheel is secured by a linch-pin ; and the ex- 
 tremities of the nave are protected from wear by two 
 rings of iron, called the linch-washer and the shoulder- 
 washer. 
 
 Nave-box. The inner surface of the nave-box is en- 
 larged about its middle portion, forming a recess, or 
 receptacle, for the lubricating material. 
 
 So long as the wheel is kept well greased, there is 
 but little difference between the friction and wear of 
 brass and cast-iron nave-boxes, but when the grease is 
 exhausted, there is a superiority in favor of brass. Cast 
 iron, however, is most generally employed, on account 
 of its cheapness. 
 
 The relation between the draught of greased and un- 
 greased wheels, is determined by experience to be, 
 
 WITH OREASE. WITHOUT GREASE. 
 
 ' " i txt„~j „_i„ a 
 
 On horizontal' ground, 
 Inclined ground, 1-24, 
 
 Irons. The remaining iron parts of a gun-carriage 
 may be divided into three classes, viz.: — 1st. Those 
 which serve to connect and strengthen the principal 
 parts, before enumerated, as the assembling-bolts, straps, 
 and bands. 2d. Those which protect the wood- work 
 from wearing away at certain points, as the trunnion- 
 plates (6), the trail-plate and shoe (7), and the wheel- 
 
 Wooden axle-trees, 
 
 65 
 
 108 
 
 Iron " 
 
 56* 
 
 61| 
 
 Wooden " 
 
 96* 
 
 162j 
 
 Iron " 
 
 95 
 
 100 
 
228 
 
 ARTILLERY CARRIAGE3.- 
 
 UN-CARRIAGES. 
 
 J* 
 
 
 guard plate (8). 3d. Those employed to fasten the im- 
 plements to the carriage. The number of the pieces of 
 the last class depends upon the character of the service 
 to which the piece belongs. In the field, mountain, and 
 prairie carriages, all the implements necessary for the 
 use of the piece are carried upon the carriage. The 
 implements of the siege-carriage are carried in store- 
 wagons. 
 
 189. Force§ acting on a gun-carriage. As the axis of 
 the bore intersects the axis of the trunnions, the entire 
 force of the charge, acting on the bottom of the bore, is 
 communicated to the carriage at the trunnion-beds. The 
 carriage being constructed symmetrically with regard to 
 the axis of the piece, we are at liberty, in the following 
 discussion, to suppose that the wheels, trunnion-beds, 
 and trail, are all situated in the same plane, and that 
 the resultant of the force of the charge is applied at the 
 point where the axis of the trunnions pierces this plane. 
 The action of the force of the charge is to move the 
 carriage along the surface of the ground (supposed to 
 be horizontal), to press the wheels and trail upon the 
 ground, and to rotate the carriage around the point of 
 contact of the trail with the ground. 
 
 Let v be the position 
 of the axis of the trun- 
 nions, and mv represent 
 the amount and direction 
 of the force of the recoil, 
 and the angle of fire. Let L be the point of contact 
 of the trail and ground, a the distance of this point frcm 
 the trunnions, a the angle which the line joining these 
 two points makes with the horizontal, G the position 
 
GUN-CARRIAGES. 229 
 
 of the centre of gravity, and p its horizontal distance 
 from the point L. 
 
 If mv be the force of the recoil, li and C the pressures 
 exerted by it upon the wheel and trail, respectively, we 
 have the relation 
 
 mv sin. d-=P-\-C. 
 
 The horizontal component acts to overcome the fric- 
 tion of the wheel and trail, and to set the carriage in 
 motion. By making f the unit of friction, and MV the 
 quantity of motion impressed on the carriage, we have 
 
 mv cos. e=f(C+B)+M V; 
 or, by substituting the value of R-\-C from the above 
 equation, and solving with reference to V, we have 
 
 tt_ mv (cos.<9 — /sin.0 V 
 ~~M~ 
 
 which is the velocity of recoil. 
 
 As the unit of friction of the wheel and trail are not 
 exactly the same, the foregoing equation will not give a 
 strictly correct value for V for field and siege carriages, 
 but it will be correct for fortress-carriages and mortar- 
 beds, which do not move on wheels, in recoil. 
 
 The force mv also acts to rotate the carriage around 
 the point L with an effect proportional to its lever arm 
 Ld, which is equal to a sin. dvL ; but sin. dvL= sin. 
 (180° — («+#),) and the moment of the force of the 
 charge, with reference to the trail, is mva sin. (180°— 
 
 This moment being equal to the moment of the weight 
 of the piece, and the moment of the quantity motion im- 
 pressed upon the carriage, or _P, we have 
 
 mva sin. (180° — a — e)= Wp+P. 
 
230 ARTILLERY CARRIAGES. LIMBER. 
 
 Wk 2 W 
 
 But JP= ; Tc being the radius of gyration of the 
 
 I/ 
 
 gun and carriage taken with reference to the trail, g the 
 force of gravity, and w the angular velocity of the gun 
 and carriage. 
 
 Substituting this value of P in the above equation, 
 and reducing, we have 
 
 i ©> 
 
 mva sin (ISO — a— e)— Wp 
 
 With this relation we can discuss, by giving different 
 values to 0, «, a, andj9, the effect of the angle of fire, 
 length of trail, position of trunnions, and centre of 
 gravity, on the stability of the carriage, or the resistance 
 which it offers to overturning by the force of the charge 
 acting at the centre of the trunnions. 
 
 LIMBER. 
 
 190. Object. Thus far a gun-carriage has been con- 
 sidered only in relation to the fire of the piece, or as a 
 ttvo- wheel carriage. To suit it to the easy and rapid 
 transportation of its load, it must be converted into a 
 four- wheel carriage, which is done by attaching it to an- 
 other two- wheel carriage called a limber. 
 
 191. Construction. The field-limber is composed 
 (see fig. 58), of an axle- 
 tree (1), a fork (2), two 
 hounds (3 3), a splinter- 
 bar (4), two foot-boards 
 (5 5), a pole (6), a pintle- 
 hook and key (7 ), twojwfe- 
 yokes(8),an&apole-pad(9). Fig. 58. 
 
 •- 
 
CONSTRUCTION. 231 
 
 A side view of this limber is also shown in fig. 59, 
 together with the manner of attaching the rear carriage 
 to the pintle-hook. 
 
 The axle-tree. The limber axle-tree is made of iron, 
 imbedded in a body of wood, as in the case of the gun- 
 carriage. 
 
 The fork. The fork constitutes the middle portion 
 of the limber, and is the portion to which the pole is 
 attached. It is formed of a single piece of wood, one 
 end of which is mortised into the axle-body, and secured 
 by the pintle-hook bolts, and the other is cut into the 
 shape of a fork, to receive the tenon of the pole. 
 
 The hounds. The hounds are two wooden rails which 
 are bolted to the axle-body and splinter-bar. They 
 serve to support the ends of the limber-chest and foot- 
 boards, and also to transmit the draught of the horses 
 to the axle-tree. The chest is secured by a stay-plate, 
 situated at the bottom of the cut in the fork, and two 
 stay-pins, which pass through holes near the rear ends 
 of the hounds. 
 
 The splinter-bar. The splinter-bar is a piece of wood 
 placed cross- wise with the pole, and is firmly secured to 
 the fork and hounds. It has four hooks, to which the 
 traces of the wheel horses are attached. 
 
 The pole. The pole, or tongue, is employed to regu- 
 late the motion, and give direction to the carriage. The 
 point of attachment of the rear carriage being near the 
 axle-tree, and there being no sweep-bar, the weight of 
 the pole is mostly supported by the collars of the rear 
 horses; it should therefore be made of strong, light 
 wood — ash is generally used for this purpose. 
 
 As the pole is liable to be broken in service, the 
 
232 ARTILLERY CARRIAGES. LIMBER. 
 
 method of attaching it to the fork should be such that 
 the fragments can be promptly removed, and a new pole 
 inserted. 
 
 The foot-hoards. The foot-boards are secured to the 
 fork and hounds in a proper position for the feet of the 
 cannoniers to rest upon, while riding upon the limber- 
 chest. 
 
 The pintle-hook. The pintle-hook is a stout iron hook 
 firmly fastened to the rear of the axle-tree, for the 
 purpose of attaching the rear carriage. This mode 
 of, attachment is simple, strong, and flexible — qualities 
 which are essential to rapid movements and great en- 
 durance. The point of the hook is perforated with a 
 hole for the pintle-key, which prevents the carriages from 
 separating while in motion. 
 
 In the old system of field-carriages, the operation of 
 limbering and unlimbering was so difficult, that a rope, 
 called a "prolonge," was used to connect the gun-car- 
 riage and limber, in action. This implement is still 
 retained, but the same necessity does not exist for 
 using it. 
 
 192. Turning. All field-carriages should admit of 
 being turned in the shortest possible space. This de- 
 pends upon the size of the front wheels, the distance 
 between the front and rear axle-trees, the position of the 
 pintle, and the thickness of the stock at the point where 
 the front wheel strikes it. Notwithstanding that the 
 front wheels are made higher in the present system of 
 field-carriages than the Gribeauval system, which pre- 
 ceded it, the carriages of the former have greater facility 
 of turning, in consequence of the diminished thickness 
 of the stock. 
 
LOCKING WHEELS. 233 
 
 193. Track. By track is understood the distance be- 
 tween the furrows formed by the wheels in the ground. 
 
 It is important that the track should be the same for 
 all carriages likely to travel the same road, in order that 
 the wheels of one carriage may follow in the furrows 
 formed by those of its predecessor, and thereby prevent a 
 loss of tractile force. The track of artillery carriages is 
 5 feet, and the extreme length of the axle-tree is 6^- 
 feet for field, and 6} feet for siege-carriages. 
 
 194. i,oad. As the forward wheels "of a carriage form 
 the ruts, they should support a smaller portion of the 
 load than the rear wheels: in field-carriag*es, the pro- 
 portion is as two to three. 
 
 195. Length of stock. The length of the stock deter- 
 mines the distance between the front and rear wheels. 
 The longer this distance is, the greater will be the space 
 required to turn the carriage in, and the greater will be 
 the effort necessary to pull the carriage over a sharp 
 elevation of the ground. 
 
 196. Wheels. All wheels of an artillery carriage 
 should be of the same height, to permit of interchange, 
 and to make the line of traction parallel to the ground. 
 
 197. Locking Wheels, The work of holding back a 
 carriage, on descending ground, devolves on the pole- 
 horses. When the descent is very steep, and the load 
 large, they are relieved of a portion of this work by 
 attaching a chain to one of the rear wheels, in such a 
 manner as to prevent it from turning, and thereby 
 changing the friction on the axle-arm to friction on the 
 ground. In field-carriages, one end of the locking-chain 
 is secured to the stock by the assembling-bolt, and the 
 other is passed around the felloe, and secured to itself 
 
234 ARTILLERY CARRIAGES. FIELD CARRIAGES. 
 
 by a key. In siege-carriages, where the load is much 
 heavier, a shoe is attached to the chain, upon which the 
 wheel rides. This prevents the tire from being worn 
 and the wheel from being strained ; at the same time, 
 the operation of locking and unlocking can be per- 
 formed without stopping the carriages. 
 
 FIELD-CARRIAGES. 
 
 198. Kind§. The carriages pertaining to the field 
 service, are the gun-carriage, the caisson, the travelling- 
 forge, and the battery -ivagon. The same limber is used 
 for all the field-carriages, with the exception of the in- 
 terior arrangement of the chest, which is adapted to the 
 kind of the carriage to which the limber is attached. 
 
 199. Gun-carriage§. Field-carriages are characterized 
 by great lightness, strength, and mobility. They are, 
 
 The 6-pdr. gun and 1 2-pdr. howitzer carriage. 
 
 The 12-pdr. gun (light) and the 1\-pdr. howitzer car. 
 riage. 
 
 The 12-pdr. gun (heavy) and the 32-pdr. howitzer 
 carriage* 
 
 These carriages are of similar construction, the only 
 difference being in the size and strength of the several 
 parts. The first is mounted on light, or No. 1 wheels, 
 and the second and third on No. 2, or heavy wheels. 
 Attached to each carriage are the following named im- 
 plements, viz., two rammers and sponges, two trail- 
 handspikes, one worm, one sponge-bucket, one tar-bucket, 
 one watering-bucket. 
 
 * The 10-pdr. Parrott and the 3-in. rifle guns are mounted on the 6-pdr. carriage, 
 and the 20-pdr. Parrott rifle-gun is mounted on the 12-pdr. (heavy) carriage. 
 
caisson. 235 
 
 200. €ais§ou. The caisson is used to transport ammu- 
 nition ; and in light field-batteries, there is one caisson to 
 each piece, in heavy batteries there are two. The am- 
 munition is contained in three chests — two mounted on 
 the body, and one on the limber. The number of rounds 
 for each chest varies with the calibre of the piece, as 
 follows, viz. : 
 
 6-pdr. gun, and 3-inch rifle-gun, . 50 
 
 12-pdr. gun, .... 32 
 
 12-pdr. howitzer, . . - .39 
 
 24-pdr. howitzer, . . . . 23 
 
 32-pdr. howitzer, . - . .15 
 
 The whole number of rounds for each piece may be 
 
 ascertained by multiplying the above numbers by four. 
 
 The caisson is composed of a body, and a limber. See 
 
 fig. 59. The body is composed of one middle and two 
 
 side rails (1), one stock (2), and one axle-tree (3). It 
 
 Fig 59. 
 
 carries two ammunition-chests (4, 5), a spare wheel (6), 
 which fits upon an iron axle-arm attached to the rear 
 end of the middle rail, one spare pole (7), fastened to 
 the under side of the stock, and a spare handspike. The 
 spare articles are needed to replace broken parts. 
 
 The caisson also carries a felling-axe, shovel, and pick- 
 axe, to remove obstructions, repair roads, &c, a tarpau- 
 
236 ARTILLERY CARRIAGES. FIELD CARRIAGES. 
 
 lin strapped on to the limber-chest, a tar-bucket, and a 
 watering-bucket. 
 
 201. Travelling-forge. The travel ling-forge is a com- 
 plete blacksmith's establishment, which accompanies 
 the battery for the purposes of making repairs and shoe- 
 ing horses. It consists of a body, upon which is con- 
 structed the bellows-house, &c, and the limber, which 
 supports the stock, in transportation. The body (see 
 fig. 60) is composed 
 of two rails (1), a 
 stock (2), and an 
 axle-tree (3). The 
 bellows-house is di- 
 vided into the bel- 
 lows-room (4), and " Fig. 60. 
 the iron-room (5). Attached to the back of the house 
 is the coal-box (6), and in front of it is the fire-place (7). 
 From the upper and front part of the bellows, an air- 
 pipe (8) proceeds in a downward direction to the air- 
 box, which is placed behind the fire-place. The vise (9) 
 is permanently attached to the stock, and the anvil, 
 when in use, is supported on a stone or log of wood, 
 and when transported is carried on the hearth of the 
 fire-place. The remaining tools are carried in the lim- 
 ber-chest. When in working order, the point of the 
 stock is supported by a prop (10). 
 
 202. Battery- wagon. The battery- wagon is employed 
 to transport the tools and materials for repairs. Among 
 the tools are those for carriage-makers, saddlers, armor- 
 ers, and laboratorians' use, scythes and sickles for cut- 
 ting forage and spare implements for the service of the 
 piece. 
 
MOUNTAIN CARRIAGE. 237 
 
 The body (1) of the battery-wagon (see fig. 61) is a 
 large rectangular box, covered with a roof of painted 
 
 Fig. 61. 
 
 canvas ; and to the back part is attached a rack (2) for 
 carrying forage. The bottom of the body is formed of 
 one middle and two side rails, resting on a stock and 
 axle-tree, as in the travelling-forge. 
 
 The tools and materials of the battery-wagon are 
 carefully packed in the manner prescribed by the Ord- 
 nance Manual, in order that no difficulty may be expe- 
 rienced in finding a particular article when wanted. 
 The smaller articles are carried in boxes properly let- 
 tered and numbered. 
 
 The travelling-forge and battery-wagon are not con- 
 fined to the service of field-batteries, but are used with 
 siege and sea-coast carriages, as occasion may require. 
 
 MOUNTAIN-CAKRIAGE. 
 
 203. Requirements, &c. The mountain-howitzer car- 
 riage should be light enough to be carried on the back 
 of a pack animal, and the axle-tree should be short 
 enough to permit it to pass through very narrow de- 
 files. 
 
 It differs in construction from the field-carriage, 
 
238 ARTILLERY CARRIAGES. PRAIRIE. 
 
 inasmuch as the stock and cheeks 
 (1) (fig. 62) are formed of the same 
 piece, by hollowing out the head of 
 the stock. The wheels are thirty- 
 's- 62 - eight inches in diameter, and the 
 axle-tree is made of wood, the arms being protected 
 from wear by skeans, or strips of iron. 
 
 The distance between the wheels is about equal to 
 their diameter. It is arranged for draught by attaching 
 a pair of shafts to the trail. The pack-saddle and its 
 harness are constructed to carry severally, the howitzer 
 and shafts, the carriage, or two ammunition chests, or it 
 enables an animal to draw the carriage, with the howit- 
 zer mounted upon it. 
 
 A portable forge accompanies each mountain battery, 
 and is so constructed that it can be enclosed in two 
 chests, and carried, with a bag of coal, upon the pack- 
 saddle. 
 
 PRAIRIE-CARRIAGE. 
 
 204. Description, &c. The prairie-carriage is designed 
 to carry the mountain-howitzer, and is similar to the 
 mountain-carriage in the form and combination of its 
 parts ; but being exclusively intended for draught, the 
 axle-tree is made of iron, the wheels are made higher, 
 and the distance between them greater than in the 
 mountain-carriage. It has a limber, and is drawn by 
 two horses abreast, as in field-carriages. The ammuni- 
 tion is packed in mountain ammunition chests, two of 
 which are carried on the limber, and the remainder in 
 a covered cart, of peculiar construction, or packed on 
 animals, as in the mountain service. 
 
SIEGE-CARRIAGES. 239 
 
 SIEGE-CAKRIAGES. 
 
 205. Kiiid§ of. The siege-carriages are 
 
 The 24rpdr. gun and 8-inch howitzer carriage. 
 
 The 18 -pdr. gun-carriage. 
 
 The 12-pdr. 
 
 The mortar-wagon. 
 
 The limber. 
 
 The mortar-bed. 
 
 206. Gun-carriage. The construction of the siege- 
 gun carriage is similar, in most -of its details, to the field- 
 gun carriage. It differs, however, in the greater strength 
 of the parts, and in the mode of attaching to the lim- 
 ber, and by the absence of the parts used for carrying 
 the implements. 
 
 The position of the trunnion-beds is such that when 
 the carriage is limbered up, the weight of the piece is 
 thrown too much on the rear wheels for convenience of 
 transportation; another set of trunnions is therefore 
 
 Fig. 63. 
 
 formed at the rear end of the cheeks, by enlarging the 
 heads of the cheek-bolts, and the piece is shifted to them 
 in transportation. They are called the " travelling trun- 
 
240 ARTILLERY CARRIAGES. SIEGE-CARRIAGES. 
 
 nions? See (1) fig. 63. The breech of the piece rests 
 in a groove formed in a block of wood, called the " bol- 
 ster 11 (2) ; and the elevating screw is disposed of by 
 reversing it in its nnt. To prevent it from unscrewing 
 by the motion of the carriage, one of the handles is 
 slipped through a leather loop attached to the under 
 side of the stock. 
 
 207. Limber. The same kind of limber is used for all 
 siege-carriages. It is composed of a fork (4), the pole 
 (5), the axle-tree (6), the pintle (7), the hounds (8), the 
 splinter-bar (9), and the friction-circle (10), one end of 
 which is only represented in the figure. 
 
 The fork constitutes the main part of this carnage, 
 and to it are attached the pintle, the pole, the splinter- 
 bar, the axle-tree, and the friction-circle. 
 
 As this carriage is not subjected to the shock of 
 firing, the axle-tree is not imbedded in wood to give it 
 stiffness, as in the gun-carriage. 
 
 The pintle is placed far enough in rear of the centre 
 of the axle-tree to enable the weight of the stock of the 
 gun-carriage to act as a counterpoise to the pole, and 
 give it steadiness when the carriage is in motion. The 
 friction-circle acts as a sweep-bar for the shoe of the trail 
 to rest upon when the limber turns around its pintle. 
 The attachment of the two carriages is secured by a 
 lashing chain and hook. 
 
 208. Mortar- wagon. The mortar- wagon is employed 
 to transport siege projectiles, mortars and their beds, and 
 spare guns. 
 
 It is composed of a limber and body. The body con- 
 sists of two middle-rails, united so as to form the stock, 
 and two side-rails. These pieces rest upon the axle-tree, 
 
PLATFORM. 241 
 
 and are strongly connected together by cross pieces of 
 wood and straps of iron. At the rear of the body is 
 placed a windlass, which aids in mounting guns and 
 mortars. Stakes are placed around the sides of the 
 body, to sustain the side and end boards which are used 
 in transporting projectiles. 
 
 209. Mortar-bed. The lightness of the mortar, and 
 the high angle under which it is fired, render it unsafe 
 to be fired from a carriage ; it is, therefore, mounted on 
 a bed, which rests directly on a platform. 
 
 The siege mortar-bed is made of a single piece of cast 
 
 iron, of a form shown in 
 fig. 64* The different 
 parts are, the cheeks (1), 
 and the front and rear 
 transoms (2, 3), shown in 
 Fi g- 64 - broken lines. To the front 
 
 transom is attached a wooden bolster, upon which rests 
 the quoin, or wedge, used in sustaining the piece at the 
 proper elevation. From the outer sides of the cheeks 
 project four pieces, called manoeuvring bolts, to which 
 handspikes are applied in moving the bed, when point- 
 ing the piece. 
 
 210. Platform. To insure accuracy of fire with heavy 
 guns and mortars, it is absolutely necessary that their 
 carriages and beds should rest upon solid and sub- 
 stantial platforms. 
 
 The platforms for siege-pieces, being transported with 
 an army, should have the greatest lightness, compatible 
 with strength to endure the shocks of long-continued 
 
 * The beds for all the new-pattern mortars are made of wrought iron — boiler 
 plate and rolled bars fastened together by screw-bolts. 
 16 
 
242 ARTILLERY CARRIAGES. — SIEGE CARRIAGES. 
 
 firing. They are composed of a certain number of pieces 
 of wood ; and in order that these pieces may be carried 
 on the backs of soldiers from the depot to the battery, 
 the weight of the heaviest piece should not exceed fifty 
 pounds. Siege-platforms consist of sleepers (1), (fig. 
 65), and deck-plank (2). The general direction of the 
 sleepers is parallel to the axis of the piece, and the 
 deck-plank at right angles to it; this disposition of 
 the parts offers the greatest 
 resistance to the recoil of the 
 carriage. The deck-planks are 
 fastened together at their 
 edges by dowels ; the outer Fig. 65 
 
 planks are secured by iron eye-pins, one at each end 
 of a sleeper. The platform is secured in its place 
 by driving stakes around the edges. 
 
 There are two principal platforms for the siege-service, 
 viz., the grim-platform, and the rawtor-platform. The 
 former is composed of twelve sleepers and thirty-six 
 deck-planks; the mortar-platform of six sleepers and 
 eighteen deck-planks. 
 
 A simple and strong mortar-platform, called the rail- 
 platform may be used where trees or timber can be 
 easily procured. This is composed of three sleepers 
 and two rails, secured by driving stakes at the angles 
 and at the rear ends of the rails. The rails are placed 
 at the proper distance apart to support the cheeks of 
 the bed. 
 
SEA-COAST CAEEIAGES. 243 
 
 SEA-COAST CARRIAGES. 
 
 211. cia§sification. Sea-coast carriages are divided 
 into barbette, casemate, and flank-defence carriages, de- 
 pending upon the part of a work in which they are 
 mounted. 
 
 212. Material. Heretofore, nearly all sea-coast car- 
 riages were made of wood ; but in consequence of the 
 great difficulty of preserving this material from decay, 
 especially when exposed to the dampness of casemates, 
 it has been determined to replace it by wrought-iron ; 
 and strong, cheap, and manageable carriages have been 
 devised and tested for this service. 
 
 The principal feature in the construction of the new 
 carriages, is a peculiar combination of boiler-plate and 
 rolled beams, which gives, with requisite lightness, great 
 strength and stiffness to the important parts. 
 
 213. Gun-carriage. All sea-coast carriages are com- 
 posed of two principal parts, viz., the gun-carriage (1), 
 and the chassis (2), (fig. 66). 
 
 \ Fig. 66. 
 
 Gun-carriage. The purpose of the gun-carriage being 
 to support the piece, it should be so constructed that 
 the piece can be elevated or depressed, in aiming ; and 
 
244 ARTILLERY CARRIAGES. SEA-COAST CARRIAGES. 
 
 run into and out of battery, in firing. The term " in 
 battery," as applied to sea-coast guns, refers to the posi- 
 tion which the piece occupies when it is ready to be* 
 fired — in casemate pieces the muzzle must be in the 
 throat of the embrasure, and in barbette-pieces, directly 
 Over the superior slope of the parapet. 
 
 The gun-carriage is composed of two cheeks, held to- 
 gether by iron straps, called transoms. 
 
 Each cheek is formed of a piece of boiler-plate, cut to 
 a triangular shape, and stiffened by ribs, made by bolt- 
 ing trough-beams to the inner sides of the cheeks. 
 Three trough-beams are placed on each cheek, in such 
 positions as will best resist the strains imposed on it. 
 These are shown by the broken lines of the figure. The 
 form of the transom-straps is shown at (3) ; the ends, 
 which are bent at right angles to the body of the strap, 
 are pierced with holes for the screw-bolts, which secure 
 them to the cheeks. 
 
 Trunnion-plates are placed on the top of the cheeks, 
 for the trunnions to rest in ; and the bottom of each 
 cheek rests upon a plate, called the shoe. The move- 
 ment of the carriage to and from battery, is regulated 
 by a pair of eccentric manosuv ring-wheels (4), which 
 are placed underneath, and a little in front of the centre 
 of the trunnions. 
 
 When it becomes necessary to check the recoil of the 
 gun-carriage, the wheels are thrown out of gear by 
 means of a handspike, and the forward part of the car- 
 riage moves on sliding-friction ; when it becomes neces- 
 sary to move it to battery, the wheels are thrown into 
 gear, and the carriage moves on rolling-friction. 
 
 Elevating-screw. The elevating-screws of sea-coast 
 
SEA-COAST CARRIAGES. 245 
 
 carriages are of two kinds. One is worked by a geared 
 nut, which is made to revolve by a bevelled spur-wheel, 
 attached to one end of a shaft at right angles to the 
 cheek. The other end of the shaft projects from the 
 right side of the carriage, and is armed with a handle 
 having four branches (5). This screw is used for low 
 angles of elevation. In pieces without preponderance, 
 a simple handspike and fulcrum are all that is required 
 to elevate and depress with facility. Elevating-screws 
 are supported by iron trough-beams, the ends of which 
 are fastened to the cheeks by screw-bolts. 
 
 Elevating -arc. The elevating-arc (8) is made of brass, 
 and attached to the upper edge of the right cheek by a 
 joint, which allows it to be folded down when not in 
 use. It is graduated, by means of a mark on the base- 
 ring, and is employed to measure the elevation of the 
 piece. It may be also used for giving direction to the 
 piece by sighting along its inner surface and the ex- 
 tremity of the rimbase. 
 
 Chassis. The chassis is the movable railway along 
 which the gun-carriage moves to and from battery. It 
 is composed of two long i shaped wrought-iron rafo 
 fastened together by transom-straps, as in the gun- 
 carriage. To retard the recoil of the piece when fired, 
 and to facilitate its motion to battery, the rails are in- 
 clined from the front to the rear, at an angle of 1 upon 
 20. 
 
 To permit the chassis to be moved horizontally, and 
 thereby to give the proper direction to the piece in 
 aiming, it is supported on traverse-wheels (6, 6), which 
 roll upon circular plates of iron, fastened to the floor of 
 the battery, called traverse-circles. 
 
246 ARTILLERY CARRIAGES. SEA-COAST CARRIAGES. 
 
 The motion of the gun-carriage is checked, in front 
 and rear, by pieces of iron, riveted to the top of the 
 rails, called hurters and counter-liurters (7, 7) ; and it is 
 prevented from slipping off sidewise, by pieces, called 
 guides, bolted to the inner sides of the cheeks. 
 
 Pintle, The pintle is the fixed centre around which 
 the chassis is traversed. It is formed of a stout piece 
 of iron, strongly secured to masonry, if the battery be a 
 fixed one, or cross-pieces of timber bolted to a platform 
 of timber which is imbedded in the ground, if it be of a 
 temporary nature. In casemate batteries, the pintle is 
 placed immediately under the throat of the embrasure, 
 and the chassis is connected with it by a stout strap of 
 iron, called the tongue. The muzzle of the piece, when 
 in battery, is situated in the throat of the embrasure — 
 a position which, taken in connection with that of the 
 pintle, gives the greatest horizontal field of fire. 
 
 In the ordinary barbette-carriage, the pintle is gener- 
 ally placed under the centre of the front transom of the 
 chassis; but in the columbiad-carriage, it is placed un- 
 der the centre of the middle transom. In the first case 
 tjje horizontal field of fire is limited to 150°; and the 
 front traverse-wheels are dispensed with. In the co- 
 lumbiad-carriage, the piece sweeps the entire horizon, 
 and the chassis is supported at a point where it is sub- 
 jected to a very great strain when the piece is fired as a 
 mortar. 
 
 The barbette-pintle can be made movable by attach- 
 ing it to a frame running upon a railway, situated along 
 the foot of the parapet. This affords the means of con- 
 centrating an increased number of pieces upon the front 
 of attack, or of protecting them from an enfilading fire, 
 
SEA-COAST CARRIAGES. 247 
 
 by removing them under the shelter of traverses. This 
 plan is employed in the Austrian service. 
 
 Prop, c&c. Props are attached to the rear extremi- 
 ties of the columbiad-barbette chassis-rails, to prevent 
 the chassis from being tipped up when the gun-carriage 
 recoils with violence against the counter-hurters ; and 
 hooks are placed along the web of the chassis-rail for 
 the attachment of the handspikes when they are not in 
 use. 
 
 214. Kinds. The different sea-coast carriages are 
 
 Barbette. 
 One for 15-inch columbiad. 
 " 10-inch " 
 
 " 8-inch 
 
 " 8-inch howitzer, 42-pdr. and 32-pdr. guns. 
 " 24-pdr. and all smaller guns. 
 
 Casemate. 
 One for 8-inch columbiad and 42-pdr. gun. 
 " 32-pdr. gun and 24-pdr. gun. 
 " 24-pdr. howitzer — flank defence. 
 
 The carriage for one calibre can be altered to fit that 
 of another, by changing the trunnion-plates and transom- 
 straps. The parts of all the carriages, as far as practica- 
 ble, are made to interchange with each other.* 
 
 * By a late arrangement, the 8 and 1 0-in. columbiads can be mounted on front 
 pintle barbette-carriages, and the 10-in. columbiad is mounted in casemate batteries. 
 
 ^/ /^ ^<^^y 
 
248 
 
 MACHINES AND IMPLEMENTS. 
 
 CHAPTER V. 
 
 MACHINES AND IMPLEMENTS 
 
 215. Object. Artillery machines are employed to 
 mount and dismount cannon from their carriages, and 
 to transport artillery material from one part of a work 
 to another. They comprise the gin, the ding-cart, the 
 casemate-truck, the hand-cart, the lifting-jack, and the 
 lever-jack. 
 
 216. Gin. A gin is a tripod formed of ash or spruce 
 poles. Two of the poles are joined together by two 
 cross-bars of wood or iron (1, 2), see fig. 67, and are 
 called the legs. The third is called 
 the pry -pole, and is used in elevating 
 the gin to its proper position. The 
 hoisting apparatus is supported by a 
 clevis which is secured by the bolt 
 which unites the legs and pry-poles ; 
 it consists of two sets of iron blocks, 
 through which is rove a rope called Fig. 67. 
 
 the fall, and which is wound around the windlass (3). 
 The windlass is worked by two handspikes which fit 
 into brass sockets, one at each extremity of the wind- 
 lass ; the operation of the handspikes is made continuous 
 by the action of the pawl of the socket on the ratchet 
 of the windlass. The piece to be raised is attached to 
 the hook of the lower block, by a stout rope called a 
 
SLING CART. 249 
 
 sling, which passes around the knob of the cascable 
 and a piece of wood projecting from the muzzle. 
 
 Kinds. There are three kinds of gins, viz. : the gar- 
 rison gin, the casemate gin, and the field and siege gin. 
 The last mainly differs from the others in the smaller 
 size and lesser strength of its parts ; the casemate gin is 
 not so tall as the garrison gin, on account of the low- 
 ness of the casemate roofs under which it is used ; in all 
 other respects the two are alike. 
 
 217. siing-cart. A sling-cart is composed of two 
 wheels of large diameter, an axle-tree, a tongue, and the 
 hoisting apparatus / and is intended to transport cannon 
 and their carriages. There are two kinds, viz. : the 
 wooden sling-cart and the iron sling-cart. 
 
 The wheels of the wooden 
 sling-cart are eight feet in 
 diameter, (figure 68.) The 
 hoisting-apparatus is a screw 
 (1), which passes vertically 
 through the wooden axle- 
 tree, and is worked by a nut 
 Fig. 68. with long handles (2). The 
 
 lower part of this screw is terminated with two hooks, 
 to which are fastened the chains and trunnion-rings (3). 
 The breech of the piece is sustained by the cascable 
 chain (4). A piece may be also raised by surrounding 
 it with a chain, fastening the chain to the hooks (5, 5), 
 and depressing the tongue, which acts as the long arm 
 of the lever. 
 
 Iron sling-cart. The iron sling-cart is smaller than 
 the wooden one, and is employed to transport cannon 
 in siege-trenches, <fcc. (figure 69.) The weight is at- 
 
250 
 
 MACHINES AND IMPLEMENTS. 
 
 Fig. 69. 
 
 tached by a chain or rope to 
 the hook (1), and is raised by- 
 pressing down the tongue (2), 
 which is made of wood. When 
 sling-carts are to be moved, they 
 are attached to the pintle of a field 
 or siege limber. 
 218. Casemate truck. The casemate truck (see fig. 70) 
 is composed of a stout frame of wood mounted on three 
 barbette traverse- wheels, and is employed to move can- 
 non and carriages through posterns and along casemate 
 galleries. 
 
 Two of the wheels are 
 placed at a, and one at h ; 
 the latter turns around a ver- 
 tical axis, when the direc- 
 tion of the truck is changed 
 by the handle (c). The rings shown in the figure are 
 for the purpose of attaching drag-ropes. 
 
 219. L.MMiig-jack. The lifting-jack is a small but 
 powerful screw, worked by a geared nut. 
 It is useful when the space for manoeuv- 
 ring is small, and the number of men is 
 limited. If the weight to be raised is 
 sufiiciently high, the lifting power is ap- 
 plied at the top (a), fig. 71; if it be low, 
 
 Fig. 70. 
 
 Fig. 71. 
 
 it is applied at the foot (5). 
 
 220. .Lever-jack. The lever-jack is another but less 
 powerful apparatus for lifting. It consists of a lever 
 of wood (a), fig. 72, resting on a bolt (c), which passes 
 through holes in two uprights (b). The height of the 
 bolt is varied by passing it through different holes in 
 
LOADING. 251 
 
 the uprights (eight in num- 
 ber), and the power of the 
 lever is regulated by a notch- 
 ed piece of cast iron screwed 
 to the under side of the lever 
 
 221. Trench cart. The trench cart is a common hand- 
 cart, employed principally in the transportation of am- 
 munition in siege-trenches. In the Crimea, trained 
 pack-mules were employed in transporting ammunition 
 and other supplies, from the depots to all parts of the 
 trenches. 
 
 IMPLEMENTS AND EQUIPMENTS. 
 
 Artillery implements and equipments are employed 
 in loading, pointing, and firing cannon, and in the ma- 
 noeuvre of artillery carriages. 
 
 222. Loading. The implements for loading cannon are, 
 
 1st. The rammer-head (1) (Jig. 73), is a short cylin- 
 drical piece of beech 
 or other tough wood, 
 F & * 3 - fixed to the end of a 
 
 long stick of ash (3), called a staff, and is employed to 
 push the charge to its place in the bore or chamber of 
 a cannon. 
 
 2d. The sponge is a woollen brush (2), attached to the 
 end of a staff, for the purpose of cleaning the interior 
 of cannon, and extinguishing any burning fragments 
 of the cartridge that may remain after firing. 
 
 In the field and mountain services, the rammer-head 
 and sponge are attached to the opposite ends of the 
 
252 MACHINES AND IMPLEMENTS. 
 
 same staff; in the siege and sea-coast services they are 
 attached to separate staves. 
 
 To protect the sponge from the weather, it should, 
 when not in use, be enclosed in a cover made of canvas 
 and painted. 
 
 3d. The ladle is a copper scoop (1), fig. 74, attached 
 
 to the end of a staff 
 for the purpose of with- 
 drawing the projectile 
 Fig. 74 of a loaded piece. La- 
 
 dles are only used for siege and sea-coast cannon, as 
 field and mountain cannon can be unloaded by raising 
 the trail of the carriage, which permits the projectile to 
 slip out by its own weight. 
 
 4th. The worm (fig. 74), is a species of double cork- 
 screw, (2), attached to a staff, and is used in field and 
 siege cannon to withdraw a cartridge. 
 
 5th. The gunner's haversack is made of leather, and 
 suspended to the side of a cannonier by a shoulder-strap. 
 It is used to carry cartridges from the ammunition-chest 
 to the piece, in loading. 
 
 6th. The pass-box is a wooden box closed with a lid, 
 and carried by a handle attached to one end. It takes 
 the place of the haversack in siege and sea-coast service, 
 where the cartridge is large. 
 
 7th. The tube-pouch is a small leather pouch attached 
 to the person of a cannonier by a waist-belt. It con- 
 tains the friction-tubes, lanyard, priming-wire, thumb- 
 stall, &c. 
 
 8th. The budge-barrel is an oak barrel covered with 
 copper hoops. To the top is attached a leather cover, 
 which is gathered with a string, after the manner of the 
 
LOADING. 253 
 
 mouth of a bag. It is employed to carry cartridges 
 from the magazine to the battery, in siege and sea-coast 
 services. 
 
 9th. The priming-wire is used to prick a hole in a 
 cartridge for the passage of the flame from the vent. It 
 is a piece of wire, pointed at one end, and the other is 
 formed into a ring which serves as a handle. 
 
 10th. The thumbstall is a buckskin cushion, attached 
 to the finger to close the vent in sponging. 
 
 11th. The fuze-setter is a brass drift for driving a 
 wooden fuze into a shell. 
 
 12th. The fuze-mallet is made of hard wood, and is 
 used in connection with the setter. 
 
 13th. The fuze-saw is a 10-inch tenon saw for cutting 
 wooden or paper fuzes to a proper length. 
 
 14th. The fuze-gimlet is a common gimlet, which 
 may be employed in place of the saw to open a com- 
 munication with the fuze composition. 
 
 15th. The fuze-auger is an instrument for regulat- 
 ing the time of burning of a fuze, by removing a cer- 
 tain portion of the composition from the exterior. For 
 this purpose it has a movable graduated scale, which 
 regulates the depth to which the augur should pene- 
 trate. 
 
 16th. The fuze-rasp is a coarse file employed in fitting 
 a fuze-plug to a shell. 
 
 17th. The fuze-plug reamer is used to enlarge the 
 cavity of a fuze-plug, after it has been driven into a pro- 
 jectile, to enable it to receive a paper fuze. 
 
 18th. The shell-plug screw is a wood screw with a 
 handle ; it is used to extract a plug from a fuze-hole. 
 
 19th. The fuze-extractor is worked by a screw, and 
 
254 MACHINES AND IMPLEMENTS. 
 
 is a more powerful instrument than the preceding ; 
 it is used for extracting wooden fuzes from loaded 
 shells. 
 
 20th. The mortar-scraper is a slender piece of iron 
 with a spoon at one end, and a scraper at the other, for 
 cleaning the chamber of a mortar. 
 
 21st. The gunner* s sleeves are made of flannel or 
 serge, and are intended to be drawn over the coat- 
 sleeves of the gunner, and prevent them from being 
 soiled while loading a mortar. 
 
 22 d. The funnel is made of copper, and is used in 
 pouring the bursting charge into a shell. 
 
 23d. The powder-measures are made of copper, of 
 cylindrical form, and of various sizes, for the purpose of 
 determining the charges of shells and cannon, by meas- 
 urement. 
 
 24th. The lanyard is a cord, one end of which has a 
 small iron hook, and the other a wooden handle. It is 
 used to explode the friction-tubes with which cannon 
 for the land service are now fired. 
 
 25th. The gunner's pincers, gimlet, and ventpunch 
 are instruments carried in the tube-pouch for removing 
 ordinary obstructions from the vent. 
 
 26th. The shell-hooks is an instrument constructed to 
 fasten into the ears of a shell, for the purpose of lifting 
 it to the muzzle of the piece. 
 
 223L Pointing. The implements for pointing are : 
 
 1st. The gunner's level (fig. 75), is an 
 
 instrument for determining the highest 
 
 points of the breech and muzzle of a cannon 
 
 when the carriage- wheels stand on uneven 
 
 Fi g . 75. ' ground. It is made of a brass plate (1), the 
 
POINTING. 
 
 255 
 
 lower edge of which is terminated by two steel points 
 (2 2) which rest upon the surface of the piece. A spirit- 
 level (3) is attached to the plate with its axis parallel to 
 the line joining the points of contact. When the level 
 is in position, the vertical slide (4) is pressed down with 
 the finger to mark the required point. 
 
 2d. The tangent-scale (fig. 76) is a brass plate, the 
 lower edge of which is cut to the curve 
 of the base-ring of the piece, and the 
 upper edge is formed into offsets which 
 correspond to differences of elevation 
 Fig. "76 f a quarter of a degree. It is used in 
 
 pointing, by placing the curved edge on the base-ring, 
 with the radius of the offset corresponding with the 
 highest point of the ring, and sighting over the centre 
 of the offset and the highest point of the swell of the 
 muzzle. . 
 
 3d. The breech sight (fig. 77), is a more accurate form 
 of the tangent scale. It consists of a vertical 
 scale (1), graduated to degrees and eighths 
 of degrees, and a curved base (2), which rests 
 upon the breech of the gun. A slide is at- 
 tached to the vertical piece, which has a small 
 hole or notch cut on its upper edge, through 
 which the aim is taken. The slide is fixed at 
 any point by a thumbscrew. 
 4th. The pendulum Kausse (jig. 78), is used to point 
 field-pieces, and at the same time to obviate the error 
 which arises when the wheels of the carriage stand on 
 uneven ground. It is composed of a scale (1), arranged 
 as a pendulum, a suspension piece (2), and a seat which 
 is screwed to the breech of the gun. A slot is cut in 
 
 Fig. 77. 
 
256 
 
 MACHINES AND IMPLEMENTS. 
 
 Fig. 78. 
 
 the suspension piece into which the scale is 
 inserted, and fastened by a pivot, which 
 allows it to vibrate in a lateral direction. 
 The scale also vibrates in a longitudinal 
 direction, as the journals of the suspension 
 piece are free to turn in the grooves cut in 
 the seat to receive them, thus assuming a 
 vertical position independently of the surface 
 of the ground on which the carriage stands. 
 In order that the line of metal which passes through the 
 centre of motion of the pendulum may be parallel to the 
 axis of the piece, a front sight (4) is screwed into the 
 swell of the muzzle, the height of which is equal to the 
 dispart of the piece. 
 
 The length of each graduation is equal to the distance 
 between the front and rear sights, multiplied by the tan- 
 gent of the corresponding angle. This rule applies in 
 graduating all breech-sights. 
 
 5th. The gunner's quadrant (fig. 79) is 
 a wooden instrument for measuring the 
 angles of elevation and depression of can- 
 non, and particularly of mortars. The 
 figure explains the nature of the instru- 
 ment and its mode of application. The 
 plumb-line and bob (1), when not in use, are carried in 
 a hole formed in the end of the long branch, and cov- 
 ered with a brass plate. 
 
 224. Manoeuvre. The principal manoeuvring imple- 
 ments are — 
 
 1st. The trail handspike (fig. 80, 1), which is made 
 of wood, and attached to the trail of a field-carriage for 
 the purpose of giving direction to the piece in aiming. 
 
 Fig. 79. 
 
MA1SXEUVRE. 
 
 257 
 
 Fig. 80. 
 
 When the carriage is 
 limbered, the hand- 
 spike is attached to 
 the cheek by means 
 of a ring and hook. 
 2d. The manoeuvring handspike (3) (fig. 80) is also 
 made of wood, but it is longer and stouter than the 
 preceding ; it is used for siege and sea-coast carriages 
 and gins. 
 
 3d. The shod handspike (2) (fig. 80) is made of 
 wood, armed with an iron point, which is turned up in 
 a way to prevent slipping on the platform. It is par- 
 ticularly useful in the service of mortars and sea-coast 
 carriages. 
 
 4th. The truck hand- 
 ike (1) (fig. 81) is made 
 of iron, and is employed 
 to work the manoeuvring: 
 Kg. si. wheels of sea-coast car- 
 
 riages, by inserting it in the holes formed in the circum- 
 ference of the wheels. 
 
 5th. The eccentric handspike (2) (jig. 81) is used to 
 throw the eccentric axis of the manoeuvring wheels of 
 sea-coast carriages into and out of gear, and for this 
 purpose it has a head, with a hexagonal hole which fits 
 upon the extremities of the eccentric axle-tree. 
 
 6th. The roller handspike (3) (fig. 81) supplies the 
 place of rear manoeuvring wheels in certain of the new 
 sea-coast gun-carriages. It is operated by inserting the 
 point of the handspike under the heel of the carriage- 
 shoe, and pressing down the long arm of the lever ; in 
 
 this way the weight of the rear portion of the carriage 
 17 
 
258 MACHINES AND IMPLEMENTS. 
 
 is thrown upon the roller (£), which moves upon the 
 rail of the chassis. 
 
 7th. The prolonge is a stout hemp rope, occasionally 
 employed in field service to connect the lunette of the 
 carriage and pintle-hook of the limber when the piece 
 is fired. It is terminated at one end with a hook, at 
 the other with a toggle, and has two intermediate rings, 
 into which the hook and toggle are fastened when 
 it is necessary to shorten the distance between the car- 
 riages. 
 
 8th. The sponge-bucket is made of sheet-iron, and is 
 attached to field-carriages; it is used for washing the 
 bore of the piece. 
 
 9th. The tar-bucket is also made of sheet-iron, and is 
 used to carry the grease for the wheels. 
 
 10th. The watering-bucket is made of sole-leather, 
 riveted at the seams, and is used to water horses. Gut- 
 ta Percha watering-buckets are sometimes used. 
 
 11th. The water-buckets are made of wood, and bound 
 with iron hoops. There are two kinds, one for the 
 travelling-forge, and the other for the service of garrison- 
 batteries. 
 
 12th. The drag-rope has a hook at one end, a loop at 
 the other, and six wooden handles placed about four 
 feet apart. It is used whenever it may be necessary to 
 employ a number of men in hauling loads, or extrica- 
 ting a carriage from a difficult part of a road. 
 
 13th. The men's-harness is similar to the drag-rope, 
 except that the rope is stouter, and the handles are re- 
 placed by leather loops which pass over the shoulders 
 of the men, to enable them to exert their strength to 
 advantage. 
 
CAREIAGES. 
 
 259 
 
 14th. The bill-hook, or hand- 
 bill (fig. 82), is used for cutting 
 twigs. 
 
 Fig. 82. 
 
 15th. The screw-jack (fig. 83) is a lifting 
 machine, composed of a screw worked by a 
 movable nut (2), supported on a cast-iron 
 stand (3). It is useful in greasing carriage- 
 wheels. 
 
 PRESERVATION AND REPAIRS. 
 
 Fig. 83. 
 
 225. Preservation. Carriages, implements, Ac., are 
 preserved in dry and airy store-houses. Each kind 
 should be piled so as to occupy the least space, and each 
 pile should be marked with the nature and number of 
 the contents, and should be convenient of access. Care 
 should be taken to place strips of board under the 
 wheels and trails of carriages, if they are stowed away 
 on a ground floor. 
 
 226. Repairs. Carriages are repaired in the field 
 from the spare parts and materials carried in the bat- 
 tery-wagons. 
 
 DESTRUCTION, ETC., OF MATERIAL. 
 
 227. carriages, &c. When it is necessary to aban- 
 don artillery material, it must be destroyed, to prevent 
 it from falling into the hands of the enemy. Caissons 
 should be blown up, or water poured over the contents. 
 Carriages should be formed into a pile, and burned ; or, 
 if it be only necessary to prevent them from being moved, 
 the spokes of the wheels and poles may be cut off with 
 
260 
 
 an axe or saw. The implements should be taken away 
 or destroyed. 
 
 228. Cannon. Cannon may be permanently or tem- 
 porarily disabled. The first is done by bursting, bend- 
 ing the chase, breaking off the trunnions, and scoring 
 the surface of the bore. 
 
 To burst an iron piece, load it with a heavy charge of 
 powder, and fill the bore with sand, or with shot, and 
 fire it at a high elevation. To bend the chase of a 
 bronze cannon, fire one piece against another, muzzle to 
 muzzle, or the muzzle of one to the chase of another, or 
 light a fire under the chase and strike on it with a 
 sledge-hammer. To break off a trunnion of an iron can- 
 non, strike on it with a heavy hammer, or fire a shotted 
 gun against it. To score the surface of the bore, 
 cause shells to burst in it, or fire broken shot from it 
 with high charges. 
 
 Cannon are temporarily disabled to prevent them 
 from being immediately used by the enemy, and when 
 they are expected to be retaken. This operation is ac- 
 complished by means of a spike. 
 
 To spike. A spike is made of hardened steel, with a 
 soft point that it may be clinched on the inside : a nail 
 without a head, or a bit of ramrod, may be used in 
 place of a regular spike. To spike a piece, drive in the 
 spike flush with the outer surface of the vent, and 
 clinch it on the inside with a rammer. To prevent 
 the spike from being blown out, wedge a shot in the 
 bottom of the bore by wrapping it with cloth or felt, 
 or by means of iron wedges, driven in with a bar of 
 iron ; wooden wedges might be easily burned out by 
 means of a charcoal fire lighted with a pair of bellows. 
 
TIMBER. 261 
 
 When a piece is likely to be retaken, a spring-spike 
 is used, having a shoulder to prevent its being too easily 
 extracted. 
 
 To unspihe. To nnspike a cannon, attempt to drive 
 the spike into the bore with a punch ; if this succeeds, 
 and the bore be obstructed, introduce powder into the 
 vent to force the obstacle out. If it do not succeed, and 
 the spike be not screwed or riveted in, and the bore be 
 not obstructed, put in a charge of powder equal to one- 
 third the weight of the shot, and ram junk- wads over it 
 with a handspike, laying on the bottom of the bore a 
 strip of wood, with a groove on the under side for a 
 strand of quick-match, by which fire is communicated to 
 the charge ; in a bronze piece, take out some of the 
 metal at the upper orifice of the vent, and pour sulphuric 
 acid into the groove before firing. If this method, sev- 
 eral times repeated, do not succeed, unscrew the vent- 
 piece, if it be a bronze cannon ; or, if an iron one, drill 
 out the spike, or drill a new vent. 
 
 To drive out a shot. To drive out a shot wedged in 
 the bore, unscrew the vent-piece, if there be one, and 
 drive in wedges so as to start the shot forward, then 
 ram it back again in order to seize the wedges with a 
 hook ; or pour powder in, and fire it, after replacing the 
 vent-piece. In the last resort bore a hole in the bottom 
 of the breech, drive out the shot, and stop the hole with 
 a screw. 
 
 MATERIALS FOE CARRIAGES, &c. 
 229. Timber. Timber and wrought iron are the 
 
262 MATERIALS FOR CARRIAGES, ETC. 
 
 principal materials used in the construction of artillery 
 carriages and machines. Of the former are: 
 
 White oak. The bark of white oak is white, the leaf 
 long, narrow, and deeply indented ; the wood is of a 
 straw-color, with a somewhat reddish tinge, tough, and 
 pliable. It is the principal timber used for ordnance 
 purposes, being employed for all kinds of artillery-car' 
 riages. 
 
 Beech. The white and red beeches are used for fuzes, 
 mallets, plane-stocks, and other tools. 
 
 Ash. White ash is straight-grained, tough, and elas- 
 tic, and is therefore suitable for light carriage-shafts ; in 
 artillery, it is chiefly used for sponge and rammer staves, 
 sometimes for handspikes, and for sabots and tool- 
 handles. 
 
 Elm. Elm is used for felloes and for small naves. 
 
 Hickory. Hickory is very tough and flexible; the 
 most suitable wood for handspikes, tool-handles, and 
 wooden axle-trees. 
 
 Black walnut. Black walnut is hard and fine-grained ; 
 it is sometimes used for naves, and the sides and ends 
 of ammunition-chests ; it is exclusively used for stocks 
 of small arms. 
 
 Poplar. White poplar, or tulip- wood, is a soft, light, 
 fine-grained wood, which grows to a great size; it is 
 used for sabots, cartridge-blocks, &c, and for the lining 
 of ammunition-chests. 
 
 Pine. White pine is used for arm-chests and packing- 
 boxes generally, and for building purposes. 
 
 Cypress. Cypress is a soft, light, straight-grained 
 wood, which grows to a very large size. On account 
 of the difficulty of procuring oak of a suitable kind in 
 
( v or THE 
 UNIVERSITY 
 
 SELECTION OF TREES. 263 
 
 the Southern States, cypress has been used for sea-coast 
 and garrison carriages. It resists better than oak the 
 alternate action of the heat and moisture to which sea- 
 coast carriages are particularly exposed in casemates; 
 but being of inferior strength, a larger scantling of 
 cypress than oak is required for the same purpose ; and 
 on account of its softness, it does not resist sufficiently 
 .the friction and shocks to which such carriages are 
 liable. 
 
 Basswood. Basswood is very light, not easily split, 
 and is an excellent material for sabots and cartridge- 
 blocks. 
 
 Dogwood. Dogwood is hard and fine-grained, suitable 
 for mal.ets, drifts, &c. 
 
 230. Selection of trees. The principal circumstances 
 which affect the quality of growing trees are soil, cli- 
 mate, and aspect. 
 
 Soil. In a moist soil, timber grows to a larger size, 
 but is less firm, and decays sooner, than in a dry, sandy 
 soil ; the best is that which grows in a dark soil, mixed 
 with stones and gravel; this remark does not apply 
 to the poplar, willow, cypress, and other light woods 
 which grow best in wet situations. 
 
 Climate. In the United States, the climate of the 
 Northern and Middle States is most favorable to the 
 growth of timber used for ordnance purposes, except 
 the cypress. 
 
 Aspect. Trees growing in the centre of a forest, or on 
 a plain, are generally straight er and freer from limbs 
 than those growing on the edge of the forest, in open 
 ground, or on the sides of hills, but the former are, 
 at the same time, less hard. The aspect most shel- 
 
264 MATERIALS FOR CARRIAGES, ETC. 
 
 tered from the prevalent winds is generally most favor- 
 able to the growth of timber. The vicinity of salt 
 water is favorable to the strength and hardness of white 
 oak. 
 
 Selection. The selection of timber trees should be 
 made before the fall of the leaf. A healthy tree is 
 indicated by the top branches being vigorous and well 
 covered w^ith leaves ; the bark is clear and smooth, and 
 of uniform color. If the top has a regular, rounded 
 form; if the bark is dull, scabby, and covered with 
 white and red spots, caused by running water or sap, 
 the tree is unsound. The decay of the topmost branch- 
 es, and the separation of the bark from the wood, are 
 infallible signs of the decline of the tree. 
 
 231. Felling. The most suitable season for felling 
 timber is that in which vegetation is at rest, whicli is 
 the case in midwinter and midsummer. Recent experi- 
 ments incline to give preference to the latter season, say 
 the month of July ; but the usual practice is to fell trees 
 for timber between the first of December and the middle 
 of March. 
 
 The tree should be allowed to attain full maturity 
 before being felled; this period, in oak timber, is gen- 
 erally at the age of seventy-five to one hundred years, 
 or upward, according to circumstances. The age of 
 hard wood is determined by the number of rings w r hich 
 may be counted in a section of a tree. 
 
 The tree should be cut as near the ground as possi- 
 ble, the lower part being the best timber; the quality 
 of the wood is, in some degree indicated by the color, 
 which should be nearly uniform in the heart- wood, a 
 little deeper toward the centre, and without sudden 
 
SEASONING AND PRESERVING TIMBER. 265 
 
 transitions. Felled timber should be immediately strip- 
 ped of its bark, and raised from the ground. 
 
 232. Defect§ of tree§. Sap. The white wood next to 
 the bark, which very soon rots, should never be used, 
 except that of hickory. There are sometimes found 
 rings of light-colored wood surrounded by good hard 
 wood; this may be called the second sap; it should 
 cause the rejection of the tree in which it occurs. 
 
 Brashtoood. This is a defect generally consequent 
 on the decline of the tree from age ; the pores of the 
 wood are open, the wood is reddish-colored, it breaks 
 short, without splinters, and the chips crumble to pieces. 
 This wood is entirely unfit for artillery carriages. 
 
 Dead-wood, &c. Wood which died before felling 
 should, generally, be rejected; so should 'knotty trees, 
 and those which are covered with tubercles or excres- 
 cences. 
 
 Cross-grained wood. Wood in which the grain as- 
 cends in a spiral form, is unfit for use in large scantlings ; 
 but if the defect is not very decided, the wood may be 
 used for naves and for some light pieces. 
 
 Splits, &o. Splits, checks, and cracks, extending to- 
 ward the centre, if deep and strongly marked, make 
 wood unfit for use, unless it is intended to be split. 
 Wind-shakes are cracks separating the concentric layers 
 of wood from each other; if the shake extends through 
 the entire circle, it is a serious defect. The centre-heart 
 is also to be rejected, except in timber of very large size, 
 which cannot, generally, be procured free from it. 
 
 233. Seasoning and preserving timber. As SOOn as 
 practicable, after the tree is felled, the sapwood should 
 be taken off, and the timber reduced, either by sawing 
 
266 MATERIALS FOE CARRIAGES, ETC. 
 
 or splitting, nearly to the dimensions required for use. 
 Pieces of thickness, or of peculiar form, such as those 
 for the bodies of gun-carriages and for chassis, are got 
 out with a saw; smaller pieces, as spokes, are split with 
 wedges. Naves should be cut to the right length, and 
 bored out, to facilitate seasoning and to prevent crack- 
 ing. Timber of large dimensions is improved by im- 
 mersion in water for some weeks, according to size, after 
 which it is less subject to warp and crack in seasoning. 
 
 Seasoning. To season or dry timber, it should be 
 piled under shelter, in such manner as to allow a free 
 circulation, but not a strong current of air, around each 
 piece. The piles should be taken down and put up 
 again at intervals, varying with the length of time the 
 timber has been cut. 
 
 The seasoning of timber requires from two to eight 
 years, according to size. Oak timber loses about one- 
 fifth of its weight in seasoning, and about one-third of 
 its weight in becoming perfectly dry. 
 
 234. Bill of timber. Timber for the ordnance depart- 
 ment is purchased in pieces of the size required to make 
 each part. A list of the pieces for a certain kind of car- 
 riage, including the contents of each piece, in board- 
 measure, is called a bill of timber. The unit of board- 
 measure is a board one foot square, and one inch thick. 
 
 235. Wrought iron. None but the best wrought iron 
 should be employed in ordnance constructions. Large 
 and peculiar-shaped pieces, as axle-trees, trunnion-plates, 
 &c, as well as those requiring great strength, are made 
 from hammered shapes, furnished by the iron manufac- 
 turer, according to prescribed patterns ; other parts are 
 made of rolled iron. Axle-trees are proved by sup- 
 
CONSTRUCTION. 267 
 
 porting them at the arms, and dropping a heavy weight 
 upon the middle of the body. 
 
 236. Construction. Timber for gun-carriages is now, 
 almost entirely, worked into shape by machinery; the 
 operations are sawing, planing, turning, mortising and 
 tenoning, dove-tailing, <fcc. 
 
 In joining together the different pieces of a carriage, 
 regard should be had to the character of the fibre of the 
 wood, and the effect of drying in changing the form of 
 the piece. If a piece be supported at both ends, as in 
 the cases of carriage-stocks, chassis-rails, &c, the great- 
 est convexity of the fibre should be placed uppermost ; 
 if in the middle, as in cases of hounds of limbers, side- 
 rails of caissons, &c, it should be placed downward. 
 
 When the pieces are to be united in pairs, as cheeks, 
 side-rails, <fcc., use such pieces as have nearly the same 
 curvature of fibre. 
 
 In drying a piece of timber, the sap-wood shrinks 
 more than the heart, and the effect will be to warp in 
 the direction of the sap ; therefore, to prevent the joint, 
 formed by the two pieces which constitute a carriage- 
 stock, from opening, the heart-wood should be placed 
 on the outside. To prevent the cheeks frorr warping 
 inward, place the heart-wood on the inside. In hounds 
 and side-rails, the heart side should be placed on the 
 outside, as this will have a tendency to tighten the 
 joints. 
 
 When pieces are to be joined, the surfaces of contact 
 and the dowels should be covered with a good coat of 
 white-lead. Bolts and bolt-holes should be well covered 
 with tallow moistened with neat's-foot oil. 
 
 The surface of holes for elevating screws and pintles 
 
2(38 MATERIALS ' FOR CARRIAGES, ETC. 
 
 should be painted. If woodwork is to be painted im- 
 mediately, it should have a priming coat of lead before 
 the irons are put on ; if not, it should receive a good 
 coat of linseed oil. 
 
 237. Painting. For service, the wood- work of car- 
 riages and machines is painted, in addition to the pri- 
 ming of lead-color, with two coats of olive paint ; the 
 iron-work, with one coat of lead, and one coat black 
 paint. Great care should be observed to protect iron 
 fortress-carriages against the corroding influence of the 
 sea-coast atmosphere ; the best means remains to be de- 
 termined by experience; at present they are covered 
 with one coat of hot linseed oil and three coats of a red- 
 dish brown paint. 
 
 238. Wlodeii, &c. The models, <fec, of all ordnance 
 "materiel" are determined by the ordnance board, 
 subject to the revision of the chief of ordnance, and 
 the final approval of the secretary of war. When a 
 model has been duly approved, copies, or drawings of 
 it, are sent to the different arsenals of construction, and 
 from these, patterns and gauges are made for the guid- 
 ance of the workmen. Patterns are generally made of 
 well-seasoned mahogany, and bound with strips of 
 brass; gauges are made of sheet iron or steel. To se- 
 cure uniformity of work at the different arsenals, it is 
 made a part of the duty of the inspector of arsenals to 
 see that the patterns correspond with the originals ; and 
 it is always the duty of the officers stationed at an arse- 
 nal, to see that the work, as it progresses, corresponds 
 with the patterns, and that none but suitable materials 
 are used. 
 
 All arsenals may be divided into two classes, viz., ar- 
 
MODELS. 269 
 
 serials of deposit and construction, and arsenals of 
 
 deposit and repairs. The arsenals of construction are 
 
 at West Troy, N. Y. ; Watertown, Mass. ; Washington, 
 
 D. C. ; Pittsburgh, Pa.; Fort Monroe, Va. ; and Fay- 
 
 etteville, N. C. 
 
 / 
 
 /r- 
 
 ./< 
 
270 SMALL- ARMS. 
 
 CHAPTER VI. 
 SMALL-ARMS. 
 
 239. History, Ancient arms consisted of three kinds: 
 1st. Hand-arms, for close conflict. 
 
 2d. Projectile arms, to attain an enemy at a distance. 
 3d. Defensive arms, to protect the body. 
 
 240. Hand-arms. Hand-arms comprised the war -club, 
 battle-axe, pike, sword, and sabre. 
 
 lstr The war -club was a stout stick, the large end of 
 which was armed with blades, or points of metal ; that 
 used by foot-soldiers was from 7 to 8 feet long, and 
 weighed from 20 to 30 pounds. It was extensively 
 used in the middle ages, and is still employed by cer- 
 tain oriental cavalry. 
 
 2d. The battle-axe was at first made of stone or bone, 
 and afterward of metal. This weapon was much used 
 by the Celts and Gauls, but principally by the Franks, 
 who hurled it with great skill and effect against an 
 enemy. 
 
 3d. The pike was generally employed both by infan- 
 try and cavalry. That for the infantry was very long, 
 as in the case of the Macedonian lance, or sarissa, the 
 length of which was about 20 feet. In some countries 
 this weapon continued to be used as late as the seven- 
 teenth century. The cavalry lance was shorter and 
 lighter than the preceding ; it is still used by certain 
 kinds of cavalry. 
 
PEOJECTILE AEMS. 27l 
 
 The Roman javelin was a short pike, about 6 -J- feet 
 long, which was thrown against the enemy. The spon- 
 toon, or half -pike, was carried by French infantry officers 
 as late as the time of Louis XV. The halberd and the 
 musket with its bayonet fixed, are pikes. 
 
 4th. Swords and sabres have usually varied in charac- 
 ter with the manner of fighting of different nations ; for 
 instance, the Gauls and Germans, who defended them- 
 selves with shields made of willow, or other light wood, 
 made use of long and flexible swords, while the Greeks 
 and Romans, who wore breastplates and helmets of 
 metal, used short and stout swords. 
 
 The knights of the middle ages carried long and 
 heavy swords, which they wielded with both hands. 
 
 241. Projectile arms. The principal projectile arms, 
 before the invention of gunpowder, were the sling, bow, 
 and crossbow. 
 
 1st. The sling was formed of a leather cap suspended 
 by two cords ; a stone was placed in the cap, a rapid 
 rotary motion was communicated by the hand, one of 
 the cords was set free, and the stone escaped in a tan- 
 gential direction, and was thrown to a distance varying 
 from 200 to 300 steps. , 
 
 • 2d. The bow was formed of a piece of highly elastic 
 wood, confined in a bent position by a strong cord at- 
 tached to its extremities ; it possessed the power of pro- 
 jecting arrows to long distances. This weapon played 
 a very important part in ancient warfare, and continued 
 to be used by civilized nations to a comparatively late 
 period. 
 
 In the middle ages, it was said, that a skilful archer 
 could fire twelve arrows in a minute, and strike a man 
 
272 SMALL-ARMS. 
 
 at a distance of 100 yards. If certain English authors 
 are to be believed, an archer who could not perform 
 this feat, was disgraced. According to their statements, 
 an arrow had sufficient force to penetrate an oak plank, 
 two inches thick, at the distance of 200 yards. 
 
 3d. The crossbow was a bow attached to a stock hav- 
 ing a channel to guide the arrow. It is said to have 
 been introduced into Europe from Asia, during the 
 Crusades, by Richard Cceur de Lion, who armed the 
 English troops with it. 
 
 At present, the use of the bow is confined to barba- 
 rous tribes alone; the skill and dexterity with which 
 it is managed by the prairie Indians of this country, 
 make it an exceedingly formidable weapon at short 
 distances.* 
 
 242. Defensive weapons. Armor, which was employed 
 to protect the most exposed part of the body, naturally 
 followed the introduction of offensive arms. At first it 
 was made of plates of wood, the skins of certain ani- 
 mals, the scales of serpents, shells of turtles, <fcc., and 
 subsequently of metallic plates, or of cloth folded in lay- 
 ers. The body was also protected in rear by movable 
 obstacles, as shields, bucklers, &c. 
 
 Among the Romans and Greeks, the infantry of the 
 line wore the helmet, the breastplate, a species of half- 
 boot protected with iron, and the buckler ; the cavalry, 
 ordinarily, wore a cuirass formed of bands of leather, 
 covered with plates of bronze. 
 
 In the time of Charlemagne, coats of mail, formed of 
 small chains, were much worn. These were followed 
 
 * Certain Circassian officers ot the Russian army carry bows and arrows to en- 
 able them in a surprise to kill the enemy's sentinels without alarming the camp. 
 
ARQUEBUSE. 273 
 
 by complete suits of metallic armor, which were worn 
 until the introduction of fire-arms. 
 
 243. Portable flre-arm§. Portable fire-arms were in- 
 vented about the middle of the fourteenth century. At; 
 first they consisted simply of a tube of iron or copper, 
 fired from a stand or support. They were loaded with 
 leaden balls, and were touched off by a lighted match 
 held in the hand. They weighed from 25 to 75 pounds, 
 and consequently two men were required to serve them. 
 The difficulty of loading these weapons, and the uncer- 
 tainty of their effects, as regards range and accuracy, 
 prevented them from coming rapidly into use, and the 
 crossbow was for a long time retained as the principal 
 projectile weapon for infantry. 
 
 Breech-loading small-arms, similar in principle to the 
 cannon described in section 66, were introduced about 
 the same time, but they were soon thrown aside for 
 want of strength and solidity. 
 
 244. Arquebuse. The difficulty of aiming hand-can- 
 non, arising from their great weight, was in a measure 
 overcome by making them shorter, and supporting them 
 on a tripod, by means of trunnions which rested in 
 forks. The breech was terminated with a handle 
 which was held in the right hand, while the match was 
 applied with the left. Thus improved, this fire-arm 
 was called the arquebuse ; it was employed in sieges, 
 and to defend important positions on the field of battle. 
 
 The next improvement in the arquebuse, was to make 
 it lighter, and enclose it in a piece of wood, called the: 
 stock, the butt of which was pressed against the left 
 shoulder, while the right hand applied the match to 
 the vent. It was still very heavy, and in aiming, the, 
 
 18 
 
274 SMALL-AKMS. 
 
 muzzle rested in the crotch of a fork placed in the 
 ground. 
 
 245. Matchlock. To give steadiness to the aim while 
 applying the match to the priming, a species of lock 
 was next devised, which consisted of a lever holding at 
 its extremity a lighted match. In firing, the lever was 
 pressed down with the finger until the lighted end of 
 the match touched the priming. This apparatus, known 
 as the serpentine, continued in use until it was replaced 
 by the wheel-lock, which was invented in Nuremburg, in 
 1517. 
 
 The wheel-lock consisted of a grooved wheel of steel, 
 which acted through a half-revolution on a piece of 
 alloy of iron and antimony, placed near a priming- 
 charge of powder. The sparks thus evolved fell upon 
 and ignited the priming-charge. 
 
 246. Pistol. The first pistol was a wheel-lock arque- 
 buse, so small that it could be held and fired from the 
 extended hand. It was invented in 1545, in Pistoia, a 
 city of Tuscany ; hence its name. 
 
 247. Pctronei. The petronel was a wheel-lock arque- 
 buse of larger calibre and lighter weight than its pre- 
 decessors. To diminish the effect of the recoil, the butt 
 of the stock was much curved, and had a broad base, 
 which was pressed against the breastplate of the 
 cuirass when the piece was fired. Two sizes of the 
 petronel were used, one for infantry and one for cavalry. 
 
 248. Musket. The musket was first introduced by 
 the Spaniards, under Charles V. The original calibre 
 of the musket was such that eight round bullets 
 weighed a pound ; the piece was, consequently, so 
 heavy that it was necessary to fire it from a forked 
 
RIFLES. 275 
 
 stick inserted in the ground. The size of the bore was 
 finally reduced to eighteen bullets to the pound ; and 
 from this arm was derived the late smooth-bored 
 musket. 
 
 249. Rifle§. It is generally stated that the rifle was 
 invented by Gaspard Zoller, of Vienna, and that it first 
 made its appearance at a target practice at Leipsic, in 
 1498. The first rifle grooves were made parallel to the 
 axis of the bore, for the purpose of diminishing the fric- 
 tion of loading forced or tightly-fitting bullets. It was 
 accidentally discovered, however, that spiral grooves 
 gave greater accuracy to the flight of the projectile, but 
 the science of the day was unable to assign a reason for 
 this superiority, and the form, number, and twist of the 
 grooves, depended on the caprice of individual gun- 
 makers. 
 
 About 1600, the rifle began to be used as a military 
 weapon for firing spherical bullets. In 1729, it was 
 found that good results could be attained by using ob- 
 long projectiles of elliptical form. The great difficulty, 
 however, of loading the rifle, which was ordinarily ac- 
 complished by the blows of a mallet on a stout iron 
 ramrod, prevented it from being generally used in. regu- 
 lar warfare. The improvements which have been made 
 in the last thirty years, principally by officers of the 
 French army, have entirely overcome this difficulty, and 
 rifles are now almost universally used in place of smooth- 
 bored arms. 
 
 The rifle has ever been a favorite weapon in this 
 country, arising, doubtless, from the peculiar circum- 
 stances which surrounded its early settlers and pioneers, 
 and on more than one occasion has it proved, in the 
 
276 SMALL-AKMS. 
 
 hands of irregular troops, a formidable weapon to its 
 enemies. Until 1855, the mass of the American infan- 
 try was armed with smooth-bored muskets, but since 
 that time it has been wholly armed with rifles. 
 
 250. Bayonet. In spite of the advantages which fire- 
 arms possessed, they, like the arms which preceded 
 them, were not suited to resist the charge of cavalry. 
 The bayonet, and firing in closed ranks, were unknown ; 
 the most skilful captains of the age, however, sought to 
 combine fire-arms with pikes, in such a manner that one 
 might afford protection to the other. The French army 
 was thus arranged in six ranks, four with muskets and 
 two with pikes; on the introduction of the bayonet, it 
 was reduced to four, and finally to three ranks. 
 
 The bayonet derived its name from Bayonne, where 
 it was first made, in 1640. At first it was formed of a 
 steel blade attached to a handle of wood, which was in- 
 serted into the bore of the barrel, except in the opera- 
 tions of loading and firing. Thirty years afterward the 
 wooden handle was replaced by a hollow socket, which 
 fitted over the muzzle of the barrel ; this change render- 
 ed the musket at all times a pike as well as a fire-arm, 
 and led to the formation of modern infantry. 
 
 £51. Flint-lock. The flint-lock was derived from the 
 wheel-lock, by substituting flint for the alloy of iron 
 and antimony, and a steel battery for the wheel. It was 
 generally introduced into the French army in 1680, and 
 continued to be used in all military services, until about 
 1842, when it gave way to the percussion-lock. 
 
 252. Loading. In proportion as fire-arms were im- 
 proved, rapidity of fire increased. In 1703, the loading 
 of the musket was performed in twenty-six times, and 
 
THRUSTING- ARMS. 277 
 
 the fire of infantry was necessarily slow. In 1744, 
 the employment of fine powder for priming was dis- 
 pensed with, and the cartridge (said to have been the 
 invention of Gustavus Adolphus) was adopted in its 
 place. 
 
 HAND-AKMS. 
 
 253. cia§§iflcation. Hand-arms are divided into three 
 classes, depending on their mode of operation. 
 
 1st. Tkrusting-arms, which act by the pojnt. 
 2d. Cutting-arms, which act by the edge. 
 3d.. Thrusting and Cutting arms, which act either 
 way. 
 
 254. General principles. The object of all hand- 
 weapons is to penetrate, directly, the person of an enemy. 
 They may be divided into three distinct parts, viz. : 1st. 
 The point, or edge, which attains the object; 2d. The 
 body, or blade, which constitutes the mass of the weap- 
 on, and transmits the force of the hand to the object; 
 and, 3d. The handle, or point of application of the 
 motive force. 
 
 The mechanical principles to which they may be re- 
 ferred, are the lever and wedge. 
 
 255. Thru§tiiig-arms. With a given force of the hand, 
 acting against a given object, the penetration of a thrust- 
 ing-weapon depends upon the power of the wedge 
 formed at its point. The effect will be modified, how- 
 ever, by the position of the axis of the wedge, for if it 
 do not coincide with the direction of the impelling 
 force, there will be a component force which acts to 
 turn the point to one side. 
 
278 SMALL- ARMS. 
 
 The blade of a thrusting- weapon should, therefore, 
 be straight, and should taper to a point. To guide it 
 easily, the centre of gravity should be found in or near 
 the handle ; this may be accomplished by grooving the 
 blade, by making the handle heavy, or by adding a 
 counterpoise to it. 
 
 Kinds. The principal thrusting-weapons are the 
 straight sword, lance, and bayonet. 
 
 The straight sword, as well as other swords, are com- 
 posed of the blade, the hilt, and the guard. 
 
 The blade (see fig. 84) is divided into the point (d), 
 the middle (c), the reinforce (b), the shoulder (a), the 
 tang, or portion which is inserted into the handle, and 
 the grooves, the number of which is equal to the num- 
 ber of faces, or, from two to four. 
 
 The length of the blade varies from 30 to 33 inches, 
 the width is from \ to \ of an inch, and the weight 1 
 to H pound. 
 
 The hilt is divided into the knob (i), and the gripe 
 (<7); the gripe is generally made of wood, covered 
 with leather or sheet brass, and wrapped with wire to 
 give it roughness, and prevent it from slipping in the 
 hand. 
 
 The guard is composed of the curved branch and 
 cross-piece (/), and the plate (e), all joined in one piece. 
 The object of the guard is to protect the hand, the plate 
 
THRUSTING-ARMS. 279 
 
 to ward off the point, and the branch, the edge of the 
 enemy's sword. 
 
 The wounds made by thrusting-swords, particularly 
 those with three or four concave sides, are very danger- 
 ous, as they close up externally and suppurate inter- 
 nally. 
 
 In experienced hands the straight sword is well 
 adapted to encounter one of its kind, but it is too weak 
 to parry the blows of a sabre. It is now but little 
 used in this country, except for ornamental purposes; 
 the sabre being preferred as a service weapon, even for 
 infantry officers. 
 
 Fig. 85. 
 
 The lance. The lance, or pike, is composed of a sharp 
 steel blade, fixed to the end of a long and slender han- 
 dle of wood. (Fig. 85). 
 
 The blade is generally from 8 to 10 inches long, and, 
 in order that it may combine stiffness with lightness, is 
 grooved after the manner of the common bayonet, leav- 
 ing three or four ridges. The base of the blade has a 
 socket, and two iron straps, for securing it to the han- 
 dle. Three small staples are sometimes fastened to the 
 handle, below the blade, for the purpose of attaching a 
 pemwn, which serves as an ornament, and to frighten 
 the enemy's horses. 
 
 The handle is made of strong, light, well-seasoned 
 wood. The lower end is protected with a tip of iron, 
 and a leather loop (c) is attached opposite the centre 
 of gravity, to enable the arm to carry and guide the 
 
280 SMALL-ARMS. 
 
 lance. The total length of a lance varies from 8^ to 11 
 feet, and the weight is about 4| lbs. 
 
 Mode of carrying. On horseback, and when not in 
 use, the lance may be carried in two ways : 1st. By 
 placing the lower end in a leather boot attached to the 
 stirrup, and passing the right arm through the leather 
 loop ; 2d. By placing the lower end in the boot, and 
 strapping the handle to the pommel of the saddle. The 
 first mode enables the horseman to take his lance with 
 him when he dismounts, and is well suited to light 
 lances. The second mode is necessary for heavy lances. 
 
 Advantages, &c. In the first shock of a cavalry 
 charge, and in the pursuit of a flying enemy, the lance 
 is a superior weapon to the sabre, as it has a greater 
 penetration, and attains its object at a greater distance ; 
 but in the hand-to-hand conflict which follows a charge, 
 the latter is superior to the former. Hence, it has been 
 customary in certain services to arm a portion of both 
 light and heavy cavalry with the lance. In the Rus- 
 sian service, the front rank of the cuirassiers, a species 
 of heavy cavalry, is armed with the lance, and the rear 
 rank with the long, straight, two-edged sabre ; and in 
 nearly every European service, the lancers constitute an 
 important part of the cavalry organization. It is also 
 a favorite weapon with the mounted Indians of this 
 country. 
 
 Bayonet. The bayonet is a pointed blade attached 
 to the end of a fire-arm, to convert it into a pike. The 
 mode of attachment should be such that the bayonet 
 will not interfere with the loading, aiming, and firing 
 of the piece ; and it should be so secure as not to be 
 disengaged in conflict. 
 
THRUSTING- ARMS. 281 
 
 The musket-bayonet is com- 
 I posed of a blade (a), (fig. 86), 
 Fig. 86. a socket (b), and a clasp (c). 
 
 The Sfefe of this bayonet is made of steel, 18 inches 
 long, and, to give it lightness and stiffness, its three 
 faces are grooved in the direction of the length. The 
 grooves are technically called flutes. (See cross-section 
 of blade.) The blade is joined to the socket by the 
 neck, which should be strong, and free from defects of 
 workmanship. 
 
 The socket is made of wrought iron, carefully bored 
 out to fit the barrel of the piece easily, and at the 
 same time closely. It is secured by a stud (brazed on 
 the barrel), which fits into a crooked channel, or groove, 
 cut in the socket, and by a movable ring called the 
 clasp. 
 
 The Sword-bayonet. Short arms, such as carbines 
 and musketoons, are sometimes furnished with bayo- 
 nets of sufficient length to enable these arms to resist a 
 charge of infantry or cavalry. 
 
 Such bayonets are gen- 
 
 erally made in the form of 
 a sword. (Fig. 87.) The 
 back of the handle has a 
 groove which fits upon a stud on the barrel, and the 
 cross-piece of the handle is perforated so as to encircle 
 the muzzle end of the barrel. The bayonet is prevented 
 from slipping off by a spring catch. 
 
 The handle is made of a solid piece of brass, with a 
 hole running through it for the tang of the blade, which 
 is secured by riveting down the point. The back of 
 the blade is turned toward the barrel, and the body is 
 
282 SMALL-ARMS. 
 
 bent outward, that neither may interfere with the hand 
 in loading. Its length is about 23 inches, and its breadth 
 1^ inches. The sword bayonet is too heavy to be car- 
 ried habitually fixed to the barrel ; ordinarily it is carried 
 as a side-arm, for which purpose it is well adapted, as 
 it has a curved cutting edge, as well as a sharp point. 
 The ordinary bayonet, when not fixed, may be used as a 
 poignard, for the personal defence of the soldier. 
 
 The bayonet contributes very much to the efficiency 
 of a military fire-arm, particularly as it enables infantry 
 to resist cavalry. Too much attention cannot be paid 
 in teaching troops the use of this arm, and inspiring 
 them with confidence in it, for it often decides the fate 
 of a battle. 
 
 256. Cutting-arms. That edge of a cutting-arm will 
 have the greatest penetration which opposes the few- 
 est points to its object; a blade with a convex edge, 
 will, therefore, have greater penetration than a straight 
 one. 
 
 The effect of a cutting-blade will be modified by the 
 manner it is applied to the surface of the object; an 
 oblique stroke, for instance, will make a deej)er cut 
 than a direct one. If the edge of the sharpest blade be 
 submitted to a microscope, it will present to the eye 
 numerous asperities, which give it the appearance of the 
 cutting edge of a saw ; it is evident, therefore, that the 
 motive force should act obliquely to the cutting edge of 
 the blade, as that enables it to rupture the layers of 
 flesh upon which it acts, in detail, and without expend- 
 ing its force upon the elasticity of several layers at 
 once, which would be the case were it to act directly 
 upon the object. 
 
CUTTING- ARMS. 283 
 
 Form of the blade. When the curvature of a blade 
 is convex on the cutting side, the part near the point 
 makes a deeper cut when it is pushed from the hand 
 that moves it, as will be the case with the blows de- 
 livered in a charge of cavalry. On the contrary, a con- 
 cave cutting-edge, like that of a sickle, acts most favor- 
 ably when it is drawn toward the person using it ; such 
 is the yataghan of the Arabs, the shape of which is that 
 of an elongated letter S. 
 
 Handling. The facility of handling a sabre, and the 
 effect of its blow, depend upon the relative positions 
 of the handle, the centre of gravity, the point of contact, 
 and the centre of percussion. 
 
 The nearer the centre of gravity is to the point of 
 contact, the more powerful will be the blow ; but the 
 difficulty of handling increases with the distance of the 
 centre of gravity from the handle. As the force of the 
 blow is the important consideration in a sabre, and 
 the facility of handling in a thrusting-sword, it is cus- 
 tomary to make the point of the blade heavier, and the 
 handle lighter, in the former than in the latter. 
 
 In certain light cavalry sabres, the centre of gravity 
 is placed about three or four inches from the handle. 
 
 In order that no part of the force be lost, the point 
 of contact should coincide with the centre of percus- 
 sion ; the position of the latter point, however, depends 
 upon the weight of the soldier's arm, if motion takes 
 place around the shoulder, and it therefore varies in 
 particular cases. 
 
 Description. The principal cutting weapon is the 
 sabre. The cutting edge is generally convex ; and the 
 degree of its curvature is the characteristic feature of 
 
284 
 
 SMALL- AKMS. 
 
 the weapon. The nomenclature of the sabre is nearly 
 the same as for the sword, the principal difference being 
 in the structure of the guard, which is made lighter or 
 heavier, as the sabre approximates the character of a 
 cutting or thrusting weapon. 
 
 There are two kinds of sabres used in the United 
 States service, viz.: the cavalry sabre, and the light- 
 artillery sabre. 
 
 Fig. 88. 
 
 The cavalry-sabre (fig. 88), being used, to a certain 
 extent, for pointing as well as cutting, has only a mod- 
 erate degree of curvature, a long blade (36 inches), and 
 a "basket-hilt" to protect the hand from the point of 
 the enemy's sword, and to carry the centre of gravity 
 toward the handle. The guard is composed of the 
 front, middle, and bach branches. The gripe is covered 
 with calfskin, and bound with wire. 
 
 Fig. 89. 
 
 The light-artillery, sabre (fig. 89), being used more 
 particularly for hand-to-hand conflicts, has a shorter (32 
 inches) and more curved blade, and a lighter handle 
 than the cavalry sabre. The guard is composed of a 
 single piece of brass, terminating in a scroll. 
 
 The blades of all sabres are grooved, to give them 
 lightness. See cross-sections of figs. 88 and 89. 
 
 257. Thrusting and cutting arms. In certain services 
 
SCABBARDS. 285 
 
 it is customary to arm the heaviest cavalry, or cui- 
 rassiers, with swords which are capable of coping with 
 the bayonet or lance. The blades are long (from 36 to 
 40 inches), light, and straight, and they have a sharp 
 point, and a single cutting edge. The hilt is heavy, and 
 of the basket form. 
 
 The only weapon of 
 the thrusting and cut- 
 ting class used in the 
 United States service Flg * 90 * 
 
 is the foot artillery sword (fig. 90), which resembles the 
 short Roman sword in its character. The blade has 
 two cutting edges, is lightened toward the handle, and 
 is 19 inches long. The guard is a simple cross-piece, 
 formed of the same piece as the handle, which is made 
 of brass. 
 
 258. Scabbards. The objects of the scabbard are to 
 carry the sword, and protect the blade from injury. 
 Scabbards are generally secured to a belt, which passes 
 over one of the shoulders, or around the waist of the 
 wearer. 
 
 For foot-troops, scabbards are made of leather, mounted 
 with metal to protect them from wear. For scabbards 
 for mounted troops, leather has not sufficient stiffness 
 and strength, and steel is used in place of it. The 
 principal objections to metal scabbards are, that they 
 are heavy, dull the edge of the blade, and make con- 
 siderable noise in striking against the equipments of the 
 horse and rider. 
 
 In certain parts of Asia, these objections are over- 
 come by making scabbards of wood, covered with leath- 
 er or raw hide. 
 
286 SMALL-ARMS. DEFENSIVE ARMOR. 
 
 DEFENSIVE ARMOR. 
 
 259. Cnirass and helmet. The defensive armor of the 
 present day consists of the cuirass and helmet — the 
 former to protect the breast and back ; and the latter, 
 the head of the wearer. 
 
 The French cuirass (fig. 91) is composed of a breast- 
 plate (a), and a back-piece (b), joined 
 together by straps. The thickness and 
 form of the breastplate are such as to 
 ward off small-arm projectiles beyond a 
 distance of forty yards; this distance 
 is assumed under the supposition that 
 Fig. 91. within it, the infantry soldier will be 
 
 too busily engaged in preparing to defend himself 
 against the cavalry soldier, with his bayonet, to fire his 
 piece. The back-piece is only made of sufficient thick- 
 ness to resist the stroke of a sword ; it is presumed this 
 will induce the wearer to present his front rather than 
 his back, when he arrives within a short distance of his 
 enemy. The middle of the breastplate is formed into 
 a ridge, and the sides slope off to reflect projectiles 
 coming from the front. The thickness at the ridge is 
 .23 in. ; from this, it tapers to the edges, where it is 
 .078 in. The back-piece is .047 in. thick, throughout, 
 and the weight of the entire cuirass is about 16.75 lbs. 
 The edges are turned up to prevent the point of a sword 
 from slipping off against the body. 
 
 The cuirass and helmet worn by the leading sapper in 
 digging a siege-trench, are thick enough in all their 
 parts to resist a bullet at the distance of 40 yards. 
 
u*^f 
 
 FABRICATION. 287 
 
 MANUFACTURE OF SWORD-BLADES, &c. 
 
 * ^ 260. Material. Sword-blades are made of double 
 shear steel, or what is better, of cast-steel. A material 
 of great toughness and elasticity, as well as hardness, is 
 made by forging together steel and iron, forming the 
 celebrated Damascus steel, which is used for sword- 
 blades, springs, &c. The damasked appearance is pro- 
 duced by the action of nitric acid and vinegar, which 
 gives a black tint to the steel parts, whilst the iron re- 
 mains white. 
 
 261. Fabrication. The operations of making sword- 
 blades are: 1st. The preparation of the skelp ; 2d. 
 Forging the blade; 3d. Tempering; 4th. Grinding; 
 5th. Retempering ; 6th. Etching ; 7th. Polishing. 
 
 The skelp. The skelp is a tapering piece of steel about 
 once and a half as thick, two-thirds as long, as the pro- 
 posed blade, and it is formed out of a rectangular bar 
 by a trip-hammer. 
 
 Forging. The first operation is to weld a piece on to 
 the large end of the skelp to form the tang. The second, 
 is to draw it out to the proper length and thickness. 
 The number of heats required depends upon the length 
 of the blade, and is generally from seven to eight. The 
 second is to stamp the grooves. The third is to give the 
 bevel to the cutting edge. This operation necessarily 
 elongates this edge, and gives a curved shape to the 
 blade, which should be regulated to suit the pattern. 
 The blade is then cut off to the right length, and the 
 tang finished. 
 
 Tempering. Forged blades are soft and flexible ; it 
 
288 SMALL- ARMS. MANUFACTURE OF SWORD-BLADES. 
 
 is necessary, therefore, to give them a certain degree of 
 hardness and elasticity. This operation is called hard- 
 ening and tempering, and requires much tact on the 
 part of the workman, in order to detect, by the eye, the 
 temperature most suitable for the quality of steel em- 
 ployed. 
 
 To harden the blade, the workman holds it in the 
 heat of a charcoal furnace, moving it back and forth to 
 heat the several parts uniformly. When its color is 
 cherry red, it is withdrawn and passed rapidly through 
 moist iron filings, to render the heat still more uniform, 
 and then plunged into cold water. It is immediately 
 withdrawn and examined, to see if it be free from the 
 coating of oxide which covers it when taken out of the 
 fire. 
 
 The blade is now very hard and brittle, and often- 
 times warped ; it is necessary, therefore, that it should 
 be partially annealed or tempered ; and, for this pur- 
 pose, it is again placed in the furnace until the surface 
 is coated with blue oxide. In this condition it is soft, 
 and in a condition to be straightened. This is quickly 
 done, and the blade is plunged into cold water, which 
 gives it the proper degree of hardness and elasticity. 
 
 Grinding. Grinding is done on grindstones which 
 revolve with great rapidity — the object being to reduce 
 all parts of the blade to the proper size. 
 
 Hetempering. The blade is partially bent and an- 
 nealed by grinding. To correct these defects it is again 
 heated to the proper color, straightened, and plunged 
 into cold water. If it have lost too much of its hard- 
 ness, and be too much bent, it should be hardened and 
 tempered as described before grinding. 
 
PKOOF OF BLADE. 289 
 
 Etching. Etching is the process of marking the blade 
 "with ornamental devices, name of maker, &c. It is 
 done by heating the blade slightly, and covering the 
 portion to be marked with a thin layer of beeswax ; the 
 design is marked on the wax with a steel point, leaving 
 the metal bare ; after this, the design is covered with 
 powdered sea-salt, and then moistened with nitric acid. 
 The acid acts only on the bare parts of the metal, leav- 
 ing them in a rough state, while the unaffected part of 
 the blade remains bright. 
 
 Polishing. The object of polishing the blade is to 
 remove the marks of the grindstones, and give it a 
 smooth finish. The polishing apparatus is a rapidly 
 revolving hard- wood wheel, and the polishing material 
 is oil and emery. Burnishing gives the deep, brilliant 
 polish peculiar to steel. The operation is the same as 
 in polishing, except that oil and emery are replaced by 
 charcoal-dust. 
 
 262. inspection of blades. The dimensions are com- 
 pared with the model, and verified by appropriate 
 gauges and patterns. 
 
 263. Proof of blade. The blade is proved : 1st. By 
 confining the point by a staple, and bending the blade 
 over a cylindrical block, the curvature of which is that 
 of a circle 35 inches diameter, the curvature of the part 
 next the tang being reduced by inserting a wedge 0.7 
 inches thick at the head, and 14 inches long ; 2d. It is 
 struck twice on each of the flat sides on a block of oak 
 wood, the curvature of which is the same as the above ; 
 3d. It is struck on the edge, and twice on the back 
 across an oak block one foot in diameter ; 4th. The 
 point is placed on the floor, and the blade bent until it 
 
 19 
 
290 SMALL- ARMS. PORTABLE FIRE-ARMS. 
 
 describes an arc having a certain versed sine. After 
 these trials, the blade is examined to see that it is free 
 from flaws, cracks, or other imperfections, and that it is 
 not set, that is to say, does not remain bent. 
 
 The scabbard is proved by letting a two-pound weight 
 fall upon it, from the height of 18 inches. The weight 
 should be only one inch square at the base ; the scab- 
 bard should not be indented. 
 
 POKTABLE FIRE-ARMS. 
 
 264. Principal parts. The essential parts of all port- 
 able fire-arms are the barrel, the lock, the stock, the sights, 
 and the mountings. The nature of the remaining parts 
 will be determined by the manner of loading and dis- 
 charging, as in muzzle-loading and breec7i-\oadmg fire- 
 arms. Portable fire-arms will be treated in the same 
 order as cannon, viz. : 1st. The general principles 
 common to the various kinds ; 2d. The peculiarities 
 arising from the uses to which they are applied ; 
 3d. The manufacture, inspection, and treatment in ser- 
 vice. 
 
 265. Barrel. The barrel is the most important part 
 of a fire-arm, its office being to concentrate the force of 
 a charge of powder on a projectile, and give it proper 
 initial velocity and direction; for these purposes, and 
 for the safety of the firer, it should be made of the best 
 materials, and with the greatest care. 
 
 Exterioi\ In determining the exterior form of a bar- 
 rel, it is not only necessary to give such thickness to the 
 different parts as will best resist the explosive effort of 
 the charge, but such as will prevent it from being bent 
 
BARBELS. 291 
 
 when used as a pike, or subjected to the rough usage of 
 the service. 
 
 Weight, to a certain extent, is necessary to give steadi- 
 ness to the barrel in aiming, and to prevent it from 
 " springing" in firing. The latter defect generally arises 
 from bad workmanship, whereby there is a greater thick- 
 ness of metal, and, consequently, less expansion, on one 
 side of the bore than the other. In certain sporting 
 rifles, where great accuracy is sought to be obtained, the 
 barrel is made to weigh from 12 to 15 lbs. ; but in the 
 military service, where it is carried by the soldier, it 
 seldom weighs more than 5 lbs. 
 
 The thickness of metal of the rifle-musket barrel at 
 the breech is 0.28 inch; from this point it gradually 
 diminishes (the exterior element being a slightly re- 
 entering curve) to the muzzle, which is 0.1 inch. 
 
 Fig. 92. 
 
 Nomenclature. The principal parts of a barrel (see 
 fig. 92) are the breech, the breech-screw (1) ; the flats (3), 
 bevels (2), and oval; the cone, and cone-seat (4); the 
 bayonet-stud and front-sights (5) ; the bore, the grooves, 
 and the lands (6). 
 
 The breech-screw is composed of the body (a), tenon 
 (b), and tang (c). The object of the breech-screw is to 
 close the bottom of the bore ; the tenon fits into a mor- 
 tise cut in the stock, and prevents the barrel from turn- 
 ing in its bed ; the tang is the part by which the breech 
 of the barrel is secured to the stock, and, for this pur- 
 
292 SMALL- ARMS. PORTABLE FIRE-ARMS. 
 
 pose, it is pierced with a hole for the tang-screw, which 
 passes through the stock, and screws into the guard- 
 plate. 
 
 The fiats are two vertical plane surfaces, situated at 
 equal distances from the axis of the bore. They serve 
 to prevent the barrel from turning in the jaws of the 
 vice when the breech-screw is taken out ; the flat, on 
 the right side of the barrel, also presents a surface of 
 contact for the lock-plate, which prevents the hammer 
 and cone from changing their relative position. 
 
 The corners of the flats are bevelled to prevent the 
 barrel from being marred, and to improve its finish. 
 
 The cone. The functions of the cone are 
 to support the percussion-cap when exploded 
 by the hammer, and to conduct the flame to 
 the vent of the piece. The parts (see Hg. 93) 
 
 Fig. 93. are the nipple ,(1), upon which the cap is 
 placed; the square (2), the part to which the wrench 
 is applied ; the shoulder (3) ; the screw-thread (4) ; and 
 the vent (5). 
 
 To increase the effect of the hammer on the cap, the 
 upper surface of the cone is diminished by chamfering 
 the corners. 
 
 The cone-seat is a projecting piece of iron welded to 
 the barrel, near the breech, for the purpose of sustaining 
 the cone. The principal parts are the female screw, the 
 vent, and the rim ; the latter prevents the flame from 
 penetrating between the lock and barrel. The position 
 of the cone-seat should be such that the vent will have 
 a direct communication with the bore. In the present 
 barrel, however, the vent makes a bend at right angles 
 with the axis of the cone, on account of the peculiar 
 
BAEEELS. 293 
 
 construction of the new self-priming lock. To prevent 
 the blow of the hammer from straining the cone, and 
 breaking it off in the cone-seat, the plane of the face of 
 the hammer should pass through the axis of motion. 
 
 Calibre. Three important points are to be considered 
 in determining the calibre of small-arms: 1st. The 
 calibre should be as small as possible, to enable the 
 soldier to carry the greatest number of cartridges; 
 with the present calibre, the number of musket-car- 
 tridges is limited to 40 ; the total weight of which is 
 about 3^ lbs. 2d. To diminish the amount of ammu- 
 nition required to supply the wants of an army, and to 
 prevent the confusion that is liable to arise from a va- 
 riety of calibres, there should not be more than two, for 
 all arms of the same service, viz., one for the musket 
 and one for the pistol. 3d. This point relates to the 
 force and accuracy of the projectile. The introduction 
 of elongated projectiles affords the means of increasing 
 the accuracy and range of fire-arms, without increasing 
 the weight of the projectile, simply by reducing the cal- 
 ibre, which diminishes the surface opposed to the air. 
 Too great reduction of calibre, however, gives a very 
 long and weak projectile ; and besides, the effect of a 
 projectile on an animate object, depends not only on 
 its penetration, but on the shock communicated by it 
 to the nervous system, or upon the surface of contact. 
 A projectile of very small calibre, having but little iner- 
 tia, does not expand well into the grooves of the bore, 
 by the action of the powder ; it is not, therefore, suited 
 to the present method of loading, at the muzzle. 
 
 The foregoing considerations led to a general reduc- 
 tion of calibre on the introduction of rifles for military 
 
294 SMALL- ARMS. PORTABLE FIRE-AEMS. 
 
 purposes. The present rifle calibre is .58 inch ; that of 
 the pistol (navy size) is .37 inch. 
 
 Length of barrel. The length of a gun-barrel is de- 
 termined by the nature of the service to which it is 
 applied, rather than by the effect which it exerts on 
 the force of the charge. It has been shown by experi- 
 ment, that the velocity of a projectile, in a smooth- 
 bored musket, increases with the length of the bore, up 
 to 108 calibres, at least ; but a musket with this length of 
 barrel, would be too heavy as a fire-arm, and too un- 
 wieldy as a pike. The length of the present musket- 
 barrel is TO calibres, or 40 inches. 
 
 Grooves. The principal cause of the deviation of a 
 projectile from its true line of flight is the rotary motion 
 which it receives in the bore of the piece, combined 
 with the resistance of the air. In a smooth-bored bar- 
 rel, variable causes conspire to produce rotation, conse- 
 quently the deviation which results from it, is variable 
 and uncertain. In addition, therefore, to giving a pro- 
 jectile the requisite initial velocity and direction, a gun- 
 barrel should be constructed to give it a certain rotary 
 motion that shall continue throughout its flight. This 
 rotary motion, for reasons stated in discussing rifle-can- 
 non, takes place around an axis coinciding with that of 
 the barrel, and is produced by spiral grooves cut on the 
 surface of the bore. 
 
 The points to be observed in constructing rifle-grooves 
 for military arms, are range, accuracy of fire, endurance, 
 and facility of loading and cleaning the bore. For ex- 
 panding projectiles, experiment shows that these points 
 are best attained by making the grooves broad and shal- 
 low, and with a moderate twist. 
 
lock. 295 
 
 The following is a description of the grooves adopted 
 by the United States government, viz. : 
 
 Number. Three. 
 
 Width, Eqnal to the lands, or one-sixth the circum- 
 ference of the bore. 
 
 Depth. Uniformly decreasing from the breech, where 
 it is .015 in., to the muzzle, where it is .005 inch. 
 
 Twist. Uniform, one turn in six feet for long or 
 musket, and one turn in four feet for § short or carbine 
 barrels. 
 
 The effect of decreasing the depth of rifle-grooves is 
 to increase the accuracy, but diminish the range. The 
 increase of accuracy, undoubtedly, arises f.om the fact 
 that the projectile is held more firmly by the grooves, 
 as it passes along the bore; while the diminution of 
 range arises from an increase of friction between the 
 projectile and the grooves. 
 
 The twist is dependent on the length, diameter, and 
 initial velocity of the projectile; in other words, it 
 should be increased in a certain proportion to the length 
 of the projectile;* and for the same weight of projectile, 
 it should be increased in a certain proportion as the 
 length of the bore is diminished. Experiment, how- 
 ever, is the surest way of determining the most suitable 
 twist for any projectile. 
 
 266. L.ocfc. The lock is the machine by which the 
 charge in the barrel is ignited. Nearly all the locks of 
 the present day belong to the percussion class, in which 
 fire is produced by the blow of a hammer upon a small 
 charge of percussion powder contained in a copper or 
 paper cap. 
 
 * See section on rifle-cannon. 
 
296 SMALL- ARMS. PORTABLE FIRE-ARMS. 
 
 The conditions to be fulfilled in the construction of 
 a military lock, are — 
 
 1st. The production of fire, and its communication 
 with the charge, should be certain, and under the per- 
 fect control of the soldier. 
 
 2d. The cap should be placed upon the cone with 
 facility, and it should not be displaced in handling the 
 piece. 
 
 3d. Fragments of the cap should not incommode per- 
 sons near by, nor should the gas generated by the explo- 
 sion of the cap corrode or injure the cone, barrel, or stock. 
 
 4th. There should be no danger of accidental ex- 
 plosions. 
 
 Nomenclature. The ordinary percussion lock is com- 
 posed (see Hg. 94) of the lock-plate (1), to which the 
 several parts are attached, 
 and by which the lock is 
 fastened to the stock; the 
 hammer (2), which strikes 
 upon the cap, and explodes 
 the composition ; the main- F te- 94 - 
 
 spring (3), which sets the hammer in motion; the tum- 
 bler (4), or axle, by which the power of the main-spring 
 is communicated to the hammer ; the sear (5), or lever, 
 the point of which fits into the notches of the tumbler, 
 and holds the hammer in the required position; the 
 notches are designated as the full-cock notch, and safety- 
 notch; the sear-spring (6), which presses the point of 
 the sear into the tumbler notch ; the bridle (omitted in 
 the figure), which is pierced with two holes for the inner 
 pivots of the sear and tumbler ; the swivel (7), which 
 joins ttie main-spring and tumbler. 
 
lock. 297 
 
 Self-priming. The foregoing constitute the essential 
 parts of an ordinary percussion-lock ; in addition to 
 these, the new service lock is supplied with Maynard's 
 self-priming apparatus.* The primer used in this ap- 
 paratus, is a long strip of paper containing about 60 
 charges of percussion-powder, distributed at uniform 
 intervals. The strip is wound up in the form of a coil, 
 and inserted in a cavity cut into the exterior surface 
 of the lock-plate, called the magazine. One end of the 
 coil protrudes through an opening in the magazine (8), 
 so that the centre of the first charge of percussion- 
 powder is directly over, but not in contact with, the top 
 of the cone. When the lock is sprung, the primer is cut 
 off by a knife-edge on the lower side of the face of 
 the hammer, carried forward and exploded on the top 
 of the cone. A feeding- finger (9), connected with the 
 tumbler, pushes out another primer, when the hammer 
 is brought to the position of " full-cock." 
 
 Other methods are used for self-priming, in some of 
 which the primer is enclosed in th cartridge itself; but 
 few are found, under all circumstances, to be as reliable 
 as the common percussion lock. 
 
 Back-action. In the back-action lock, the main-spring 
 is placed in rear of the tumbler, and the sear-spring, as 
 a separate part, is dispensed with. The mortise, which 
 forms a bed for this lock, seriously affects the strength 
 of the stock at the handle ; and, for this reason, the 
 front-action lock is generally preferred for military 
 arms. 
 
 'Accidents. If the head of the hammer be allowed to 
 
 * In 1861, the self-priming apparatus was omitted in all arms of the U. S. ser- 
 vice, as it was not found to work well in practice. 
 
298 SMALL- ARMS.- — PORTABLE FIRE-ARMS. 
 
 rest on the cap, an explosion will be liable to follow an 
 accidental blow on the hammer. 
 
 267. stock. The stock i3 the wooden part of a fire- 
 arm, to which all the parts are assembled. 
 
 Fig. 95. 
 
 The most important portions of the stock (see fig. 96) 
 are the butt (1), the handle (2), the head (3), the grease- 
 box* (4), the beds for the barrel, lock, band-springs, guard- 
 plate, butt-plate; the shoulders for the tip and bands, 
 and the rarnrod-groove. 
 
 The material of the stock should be light and strong. 
 Well-seasoned black walnut is generally used for mili- 
 tary small-arms. 
 
 The butt is intended to rest against the shoulder, and 
 support the recoil of the piece ; it should be of such 
 length and shape as will enable it to transmit the recoil 
 with the least inconvenience to the soldier. The longer 
 it is, to a certain extent, the more firmly will it be press- 
 ed against the shoulder, and the effect of the recoil will 
 be a push rather than a blow. The stock is crooked at 
 the handle, for convenience in aiming, and for the pur- 
 pose of diminishing the direct action of the recoil. 
 Changing the direction of the recoil, in this manner, 
 causes the piece to rotate around the shoulder with an 
 intensity proportional to the lever arm a b / whence it 
 follows that, if the stock be made too crooked, the butt 
 will be liable to fly up and strike the soldier's face. 
 
 268. Sights. The sights are guides by which the piece 
 
 * Omitted in 1861. 
 
SIGHTS. 299 
 
 is given the elevation and direction necessary to hit the 
 object. There are two, called front and rear sights. 
 
 The front sight is fixed ; in the rifle-musket it is 
 formed by sharpening the top of the bayonet-stud, so 
 that its edge shall present a point to the eye of the 
 marksman. The fineness of this point is regulated by 
 the length of the barrel, or distance from the eye, and 
 the size and distance of the objects generally aimed at; 
 it is made coarser in military than in sporting arms, to 
 prevent injury. 
 
 The rear sight is composed of a base, which is firmly 
 secured to the barrel at a short distance from the breech, 
 and a movable part capable of being adjusted for dif- 
 ferent elevations of the barrel. The sight originally 
 affixed to the rifle-musket had a single leaf, to which 
 was attached a slide, containing the sight notch, which 
 could be adjusted for all distances between 100 and 
 1,000 yards. By a late order of the war department, 
 this has been replaced by a sight which has three mov- 
 able leaves, turning on a common axis, and bearing 
 notches adjusted to 100, 300, and 500 yards, respect- 
 ively. 
 
 Aiming a fire-arm consists in bringing the top of the 
 front sight, and the bottom of the notch of the rear 
 sight, into the line, joining the eye and the object. A 
 sight for a military arm should satisfy the following 
 conditions, viz. : 1st. It should be easily adjusted for all 
 distances within effective range; 2d. The form of the 
 notch should permit the eye to catch the object quickly ; 
 3d. It should not be easily deranged by the accidents 
 of the service. 
 
 The globe and telescopic sights are used for very accu- 
 
300 SMALL-AEMS. PORTABLE FIRE-ARMS. 
 
 rate sporting-arms, but they are too delicate in their 
 structure, and too slow in their operation, for general 
 purposes. 
 
 In the absence of a proper rear sight, the soldier of 
 the line may be taught to point his piece by aiming 
 over the centre of the knuckle of his left thumb ; the 
 position of the thumb along the barrel determines the 
 elevation of the piece. This method is practised by 
 certain French troops of the line, for distances less than 
 400 yards. 
 
 269. Mountings The mountings comprise the butt- 
 plate, the guard-plate, the bands, springs, and tip. 
 
 The butt-plate protects the end of the stock from in- 
 jury by contact with the ground ; it is curved to fit the 
 shoulder in firing, and is secured in its place by two 
 wood-screws. 
 
 The guardplate strengthens the handle of the stock, 
 and serves as a fulcrum for the trigger. It is secured 
 by the tang-screw and two wood-screws. 
 
 The trigger is a lever used to disengage the point of 
 the sear from the notch of the tumbler, which sets the 
 lock in motion. The force required to set off the trig- 
 ger, if very great, may disturb the accuracy of the 
 aim ; if it be slight, the piece will be liable to accidental 
 discharges, as in the case of the hair-trigger used in 
 target-pieces. 
 
 The guard-bow protects the finger-piece of the trigger 
 from injury, and from accidental blows that might pro- 
 duce explosions. 
 
 The bands secure the barrel to the stock, and the 
 springs keep the bands in their places. If the piece be 
 intended to be carried upon the soldier's back, it is pro- 
 
BREECH-LOADING ARMS. 301 
 
 vided with two swivels, one of which is fastened to the 
 guard-bow, and the other to a band. 
 
 270. Ramrod. The ramrod is the long, slender piece 
 employed in muzzle-loading arms, to push the charge to 
 its proper place, and to wipe out the barrel. It is 
 carried in a groove cut into the under side of the stock, 
 and it is kept in its place by the pressure of the swell 
 against the tip of the stock. The head of the rod is 
 countersunk to fit the point of the projectile ; and the 
 point has a screw to receive the wiper and ball-screw — 
 implements that are used to clean and remove obstruc- 
 tions from the bore. 
 
 x^ 
 
 BREECH-LOADING ARMS. 
 
 271. General description. The term " breech-loading" 
 applies to those arms in which the charge is inserted into 
 the bore through an opening in the breech ; and, as far 
 as loading is concerned, the ramrod is dispensed with. 
 
 The interior of the barrel of a breech-loading arm, is 
 divided into two distinct parts, viz., the bore proper, or 
 space through which the projectile moves under the in- 
 fluence of the powder ; and the chamber in which the 
 charge is deposited. The diameter of the chamber is 
 usually made a little larger, and that of the bore a little 
 smaller, than that of the projectile ; this arrangement 
 facilitates the insertion of the charge, and causes the 
 projectile to be compressed, and held firmly by the 
 lands in its passage through the bore. As before 
 stated, this operation is called slugging the projectile. 
 The bottom of the grooves, and the surface of the cham- 
 ber, are continuous. 
 
302 SMALL-ARMS. BREECH-LOADING. 
 
 272. Closing the breech. The distinguishing feature 
 of a breech-loading arm is the method of closing the 
 breech. The systems at present used may be referred 
 to two classes — those with movable chambers, and those 
 with faced chambers. 
 
 The movable chamber is formed in a separate piece 
 from the barrel, and the joint, or opening, is necessarily 
 in front of the charge ; the fixed chamber is formed by 
 counterboring the bottom of the bore, and the opening 
 is in rear of the charge. As a general rule, the mechan- 
 ism of the fixed chambered pieces is stronger and sim- 
 pler than that of movable chambered pieces, and is, 
 therefore, to be preferred, for military purposes. 
 
 273. Escape of gas. One of the most serious defects 
 of breech-loading arms was the escape of gas through 
 the joint; this not only incommoded the soldier and his 
 comrades, but seriously interfered with the working of 
 the machinery, and the accuracy and force of the fire. 
 The great attention that has been paid to the subject 
 of breech-loading arms, in the last few years, has led to 
 an improvement which entirely removes this defect, and 
 this consists in closing the joint at the* moment of dis- 
 charge, by the action of the gas itself. This operation, 
 which is called " packing the joint," is now accomplished 
 in a variety of ways, all of which may be divided into 
 two general methods: 1st. By the use of a cartridge- 
 case of sheet-brass, India-rubber, or other material ; 2d. 
 By the use of a thin elastic ring of metal which over- 
 lies the joint. By the first method, the case is perma- 
 nently distended, and some arrangement is required to 
 remove it from the chamber. Generally speaking, the 
 case is not so much injured but that it can be safely 
 
SHARP'S SYSTEM. 
 
 303 
 
 used for several fires. In the second method, the ring, 
 
 or gas-check, is a part of the arm ; and its elasticity 
 
 causes it to return to its original form after the discharge. 
 
 274. Burn§ide'§ system. An example of the first 
 
 method is shown in 
 
 This 
 
 96) has 
 
 chamber, 
 
 by turn- 
 
 Burnside's arms 
 piece (see Hg 
 a movable 
 which opens 
 
 Fig. 96. 
 
 ing on a hinge (a). The joint (b) through which the 
 gas tends to escape is covered by the embossed portion 
 of a thin brass cartridge-case, which packs the joint, 
 and cuts off the escape of gas. The case is made coni- 
 cal, that it may be easily disengaged from the chamber 
 by the movable pin (<?), after firing. 
 
 The small end of the case has a hole for the passage 
 of the flame from the cap, which is closed with wax to 
 protect the powder from moisture. A leather wad and 
 a small quantity of grease are placed between the pow- 
 der and ball, to soften and remove the dirt from the 
 bore after each discharge. 
 
 The advantages of this class of guns are, the strength 
 and water-proof nature of the cartridges, a perfectly 
 tight joint, and entire freedom in the working of the 
 machinery. The principal disadvantage is the cost and 
 peculiarity of the cartridge. 
 
 275. Sharp's system. This 
 carbine (see fig. 97) has 
 a fixed chamber, and the 
 breech is closed by a slide 
 (a) which moves nearly at 
 rig. 97. a right-angle to the axis of 
 
304 SMALL-ARMS. BREECH-LOADING. 
 
 the barrel. Formerly there was no attempt made to 
 prevent the escape of gas through the joint, and great 
 difficulty was experienced in working the slide, after a 
 few discharges in very dry weather. By boring a re- 
 cess into the face of the slide, opposite to the chamber, 
 and inserting a tightly -fitting ring (b />) into it, in such 
 manner that the inner rim is pressed against the end of 
 the barrel at the instant of discharge, the escape of the 
 gas is prevented. 
 
 This piece is loaded by depressing the lever which 
 withdraws the slide and opens the breech. The car- 
 tridge is inserted, the bullet penetrates as far as the 
 shoulder of the chamber, leaving a portion of the paper 
 and powder projecting; this is cut off by the upward 
 motion of the slide, and the powder is exposed to the 
 action of the cap. A portion of the chamber, surround- 
 ing the bullet, is enlarged in diameter (cc) y in order 
 that the accumulation of dirt may not prevent the 
 bullet from being pushed forward to its place, and 
 thereby increasing the amount of powder cut off by 
 the slide. 
 
 1 ■ / * 
 
 
 
 I ... c d : \ ■:■ ■ ~i 
 
 h J 2 
 
 Fig. 98. 
 
 276. Maynard'§ system. The chamber (a), (see fig. 
 98) of the Maynard carbine, is fixed. The barrel is 
 hinged to the stock, and, by means of a lever, which 
 also serves as the trigger-guard, the breech is raised to 
 receive the cartridge, and lowered to close it. The car- 
 tridge-case (<?) is made of brass, or other elastic metal, 
 
maynaed's system. 305 
 
 and is cylindrical in shape. It has a flange (£) soldered 
 to the bottom, to facilitate handling, and the vent is in 
 the centre of the bottom. 
 
 The bullet (d) is solid at the base ; it is cylindrical 
 as far as it is inserted into the cartridge-case, thence 
 tapers ovoidally to the front, and terminates in a flat 
 surface perpendicular to the axis.* It has but one 
 groove in the cylindrical part, which contains the lubri- 
 cant. The diameter of the bullet is equal to that of 
 the bore, plus the depth of the grooves. In charging 
 the cartridge, the bullet is set with its axis coincident 
 with the axis of the cartridge ; it is, therefore, coinci- 
 dent with that of the bore, when the piece is loaded. 
 There being no hollow in the base of the ball, there is 
 ho unequal expansion to change the position of its axis 
 while in the gun; the bullet, therefore, leaves the gun 
 in the proper direction. The barrel may be said to act the 
 part of a die to give each bullet the same form and size. 
 
 In loading the cartridge, the bullet is not pressed 
 upon the powder — the fire from the primer entering the 
 vent more freely when the powder is loose. The vent 
 of the cartridge, which is very small, is closed by a 
 small quantity of the lubricant, which does not impede 
 the passage of the flame, as it is driven into the case by 
 the confined air in advance of the flame. 
 
 The cartridge expands from the pressure within, so 
 as to cut off all escape around it ; being elastic, and the 
 expansion being within the elastic limit, it contracts so 
 
 * By this means, it is thought that the air is deflected more effectually from the 
 sides of the projectile, and the friction which opposes rotation is diminished. It is 
 not found to detract from the range, a fact which favors the existence of Newton's 
 theoretical solid of least resistance, which is likewise terminated with a plane aur* 
 face. 
 
 20 
 
306 SMALL- ARMS. BREECH-LOADING. 
 
 sa to be easily withdrawn; and, as it is supported on 
 all sides when fired, it is not injured by use. 
 
 The only instrument required for loading the case is 
 a tube closed at one end, by a bottom shaped like the 
 front end of the bullet — as large internally as the car- 
 tridge, and weighing about two ounces. 
 
 The Maynard musket, for using the same system of 
 ammunition, is like the ordinary musket, in every par- 
 ticular except that an oblong opening is made in the 
 upper side of the barrel, extending from the front end 
 of the breech-pin 1.3 in., into which opening is fitted a 
 solid block, hinged to the left side of the barrel and 
 filling the bore, so as to be, in effect, a movable exten- 
 sion of the breech-pin. The barrel is chambered for 
 the cartridge. The hinged block is the cone-seat. By 
 turning the cone-seat over to the left, the barrel is 
 opened so that the cartridge may be inserted. By 
 turning it back again the cartridge is secured in place, 
 and the vent from the cone is brought in apposition 
 with that of the cartridge. Instead of a flange on the 
 cartridge, to facilitate handling, there projects from the 
 bottom a short arm, or a thong, which is received into 
 a notch in the side of the barrel. There being only a 
 direct backward pressure upon the cone-seat (which is 
 resisted by the breech-pin), a simple snap-bolt keeps it 
 in place. With an empty cartridge case in the chamber, 
 this forms a muzzle-loading arm for ordinary ammu- 
 nition — an advantage of importance under some cir- 
 cumstances. It is asserted that this musket can be 
 made as cheaply as the ordinary one, and it has been 
 shown that the ordinary one can be changed to this 
 system, so as to be neat in appearance, strong, and 
 
SMALL-ARM PROJECTILE. 307 
 
 simple, and at a very small cost. The opening in the 
 barrel facilitates greatly the perfect cleaning and in- 
 spection of the bore — points of much importance. 
 
 The foregoing breech-loading arms are particularly 
 referred to for the purpose of illustrating the principles 
 of the classification, and because their peculiar merits 
 have been established, and the pupil will be likely to 
 meet with them in service. 
 
 277. Advantages, &c. The advantages of breech-load- 
 ing over muzzle-loading arms are : 1st. Greater security 
 from accidents in loading ; 2d. The impossibility of get- 
 ting more than one cartridge in the piece at the same 
 time ; 3d. Greater facility of loading, under all circum- 
 stances, and particularly when the soldier is mounted, or 
 is lying upon the ground ; 4th. The security with which 
 the charge is kept in its place when the piece is carried 
 on horseback with the muzzle down. 
 
 The disadvantage of breech-loading arms is the com- 
 plicated nature of the machinery, and their consequent 
 want of strength and solidity when subjected to rough 
 usage. It cannot be denied that, in spite of this disad- 
 vantage, breech-loading arms are steadily progressing 
 in favor for the mounted service, and in some European 
 services they are used, to a certain extent, by foot troops 
 of the line. 
 
 SMALL-AKM PKOJECTILES. 
 
 278. Forcing. "Forcing," as applied to a projectile, is 
 the operation by which it is made to take hold of the 
 grooves of a rifled barrel, and follow them in its passage 
 through the bore. It may be accomplished in various 
 ways, most of which depend upon the soft and yielding 
 
308 SMALL-ARMS. PROJECTILES. 
 
 nature of lead, the material of which small-arm projec- 
 tiles are made, viz. : 
 
 1st. By the action of the ramrod. 
 
 2d. By the action of the powder. 
 
 3d. By the action of ramrod and powder combined. 
 
 4th. By the form of the bore or projectile, as in 
 breech-loading arms, <fcc. 
 
 279. By the action of the ramrod. When rifles were 
 first made, forcing was effected by making the projectile 
 a little larger than the bore, and driving it down with a 
 mallet applied to the point of the ramrod; although 
 this caused the lead to fill the grooves completely, con- 
 verting the projectile into a screw, whereof 
 the barrel was the nut ; the operation was 
 slow and laborious, and the accuracy of the 
 projectile was impaired by the consequent 
 
 Fig. 99. disfiguration. 
 
 The form of the grooves then used is shown in Hg. 99. 
 They were liable to be injured by the ramrod, and were 
 difficult to clean. 
 
 280. Patch. The foregoing plan was improved by 
 making a projectile a little smaller than the bore, and 
 wrapping it with a patch of cloth, greased, to diminish 
 friction in loading. The thickness of the cloth was 
 greater than the windage; this caused the patch to 
 press upon the projectile with so much force as to com- 
 pel it to follow the winding of the grooves without ma- 
 terially altering its shape. The patch is still used in 
 sporting rifles, and gives excellent results ; but the load- 
 ing is too slow and difficult for a military arm. 
 
 281. Deivigne'§ plan. M. Delvigne, an officer of the 
 French infantry, appears to have been the first person 
 
TIGE, OR SPINDLE. 309 
 
 who overcame the difficulty of loading rifles, thereby re- 
 moving the principal obstacle to their introduction into 
 the military service. The plan proposed by him, in 
 1827, was to make the projectile small enough to enter 
 the bore easily, and to attach it to a sabot, or block of 
 
 wood (a, fig. 100), which, when 
 in position, rested upon the 
 the shoulders of a cylindrical 
 chamber (b), formed at the bot- 
 Fig - 10 °- torn of the bore, to contain the 
 
 powder. In this position, the projectile was struck two 
 or three times with the ramrod, which expanded the 
 lead into the grooves of the barrel. To the bottom of 
 the sabot was attached a piece of greased serge, which 
 served to soften the residuum of the powder and facili- 
 tate the loading. By this plan the accuracy of the 
 round projectile was increased, but its range was di- 
 minished. 
 
 Elongated projectile. In 1742, Robins pointed out 
 the superiority of the oval, or elongated form of projec- 
 tile, and since this many attempts have been made to 
 employ it in rifled arms, especially in this country, but 
 it remained for M. Delvigne, followed by MM. Thouve- 
 nin and Minie, of the French service, to apply it suc- 
 cessfully to the military service. 
 
 The form of projectile proposed by these officers was 
 composed of a cylinder and conoid. The cylinder 
 served as the base of the projectile, and gave it stability 
 in the bore of the piece; the conoidal surface, which 
 formed the point, was well adapted to diminish the 
 effect of the air, by increasing the penetrating power of 
 the projectile. A single groove was formed around the 
 
310 SMALL-ARMS. PROJECTILES. 
 
 cylinder, to contain a greased woollen thread, in place 
 of the woollen patch of Delvigne. 
 
 It was shown by the trials which followed, that the 
 presence of this groove improved the accuracy of the 
 projectile — a fact which gave a new turn to the inves- 
 tigations, and , led to the adoption of two additional 
 grooves. The theory advanced in explanation of the 
 action of these grooves was, that they oppose a resist- 
 ance to the air, which, acting on the rear portion of the 
 projectile, tends to keep the point foremost in flight, 
 thereby rendering the resistance of the air uniform, and 
 at the same time a minimum. 
 
 The correctness of this theory may be well questioned ; 
 but that the grooves exert a beneficial effect, by dimin- 
 ishing adhesion to the surface of the bore, and by facili- 
 tating expansion, can scarcely admit of a doubt. 
 
 282. Tige, or spindle. Colonel Thouvenin proposed 
 to replace the chamber of Delvigne by a spindle of 
 iron, screwed into the centre of the breech-screw (see a, 
 
 fig. 101). This was found 
 to be an excellent point 
 
 of support for the base 
 of the elongated bullet 
 when forced by the blows 
 Fi e- 10L of the ramrod. The ex- 
 
 pansion of the lead into the grooves secured the bullet 
 in place, and protected the powder from moisture. 
 
 Considerable difficulty, however, was experienced in 
 cleaning the space around the spindle; and, like all 
 plans of forcing by the ramrod, it is subject to variation, 
 arising from the particular care and strength exercised 
 by the soldier. 
 
BY THE POWDER. 
 
 311 
 
 Fig. 102. 
 
 283. By form of projectile. This method of forcing is 
 illustrated in the Whitworth rifle. The form of the 
 bore, as in the cannon, is a twisted hexagonal prism, 
 making a complete turn in 20 inches. The projectile 
 
 (fig. 102) is made nearly of the exact form and 
 size of the bore, and is about three diameters 
 in length. To prevent disfiguration and strip- 
 ping* which are very liable to occur in bul- 
 lets of this length, fired with high velocities, 
 the lead is hardened by alloying it with tin 
 and manganese; and to obviate fouling, a 
 greased wad is placed between the powder 
 and bullet. As might be expected from the length 
 of the bullet, the amount of twist, and the extreme ac- 
 curacy with which the bullet fits the bore, the results 
 obtained with this arm are much superior to those ob- 
 tained with service-arms. 
 
 284. By the powder. It appears that the first attempt 
 to force a projectile by the action of the powder was 
 made by Mr. Greener, an English gunsmith, in 1836. 
 The plan which he tried consisted in forming a cavity 
 at the base of an oblong bullet, and partially inserting 
 in it a conical pewter wedge, which was driven in by 
 the force of the powder in such manner as to expand the 
 outer part of the bullet into the grooves of the barrel. 
 
 Some years after this, Colonel Minie pro- 
 duced a projectile constructed on the same 
 principle, but instead of a solid wedge, he 
 used a cup of sheet iron, which was inserted 
 into a conical cavity (fig. 103) at the base 
 
 Fig. 103. 
 
 * Stripping is the tearing away of the metal when the projectile passes out of 
 the bore without following the grooves. 
 
312 SMALL- ARMS. PROJECTILES. 
 
 of the bullet. The point of the ball was cut off to 
 prevent disfiguration by the flat head of the ramrod. 
 This projectile, when fired from a rifle of service calibre, 
 generally possessed great range and accuracy ; but it had 
 certain defects which prevented it from being exten- 
 sively used in military service, viz. : it was compound in 
 its structure ; the cup was sometimes forced in obliquely, 
 producing unequal expansion; and, from the large size 
 of the cavity, the top was occasionally blown off, leaving 
 the cylindrical portion adhering to the sides of the bore. 
 
 285. Present methods. Not long after the introduc- 
 tion of the .Minie bullet, it was discovered that, by giv- 
 ing a suitable size and shape to the cavity, the wedge 
 could be dispensed with. The projectile thus obtained 
 was simple in its structure, and gave better and more 
 reliable results than the one from which it was derived. 
 
 The particular form and mode of expanding bullets, 
 varies in most military services ; in general terms, how- 
 ever, all modern small-arm projectiles are cylindro-con- 
 oidal in shape, and a majority of them are forced by the 
 action of the powder. The effect of the powder may 
 be direct, as in the case where it acts in the cavity of 
 a bullet; or it may be indirect, as when it compresses 
 the bullet lengthwise, or, technically, "upsets" it. 
 
 286: United states. The bullet used in the United 
 States service, is derived from that of 
 the carabine a tige, chiefly, by making / v \ 
 a conical cavity in its base. (See ^g. I \ 
 
 104.) The shape of the first cavity [ ~~**~— .JL ^ 
 employed, was that of a frustum of e /\ \ 
 a cone; but this was found defective C/ \) 
 when used in the rifle-musket, inas- Fig. 104. 
 
313 
 
 much as it rendered the bullet too weak at the juncture 
 of the two exterior surfaces. For arms with reduced 
 charges of powder, as in the carbine and pistol, the 
 large cavity is most suitable. 
 
 A description of the musket-bullet has been given in 
 chapter II. A distinguishing feature of this bullet is, 
 that no patch of any kind is used in loading ; in nearly 
 all other modern bullets a greased patch of cloth, or 
 paper, envelops them when placed in the bore. 
 
 287. England. The British bullet (sometimes known 
 as the Pritchett bullet) has a perfectly smooth exterior, 
 (fig. 105.) A conical plug of box- wood is 
 inserted into the opening of the cavity, it is 
 said, more for the purpose of preserving the 
 form of the bullet in transportation than 
 aiding in the expansion. The diameter and 
 weight of this bullet are nearly the same as 
 in the United States bullet. Fig. 105. 
 
 288. France. Two distinct bullets are employed 
 in the French army. The first is shown in fig. 101 ; 
 it is heavy, and is intended to have great force and 
 accuracy at long distances. It is used by troops 
 armed with the carabine a tige, as the Chas- 
 seurs and Zouaves. The second bullet is 
 shown in Hg. 106 ; it is light, and without 
 much accuracy, describes a flattened trajec- 
 tory, which increases the chances of hitting 
 a line of men at the usual fighting distance, fl* 106. 
 This bullet is used by troops of the line, who are not 
 supposed to be skilful marksmen. 
 
 289. Austria. The Austrian bullet belongs to the 
 class of solid expanding projectiles. In this particular 
 
314 SMALL-ARMS. CHARGE OF POWDER. 
 
 case, expansion is effected by the crowding tip of the 
 disks, formed by cutting two deep grooves 
 around the cylinder. (Fig. 107.) A portion 
 of the Austrian rifles (those carried by the 
 non-commissioned officers, and men of the 
 third rank, who act as skirmishers) have a 
 spindle attached to the breech-screw ; the ob- 
 ject of which is, not to aid in expanding the Flg ' 107 
 bullet, but to give it an invariable position with reference 
 to the powder, and thereby secure uniformity of action. 
 
 290. Switzerland. Fig. 108 ghows the form of the 
 bullet used in the Swiss service. It is solid, and 
 is forced by a cloth patch tied around the 
 grooves. The position of the bullet with refer- 
 ence to the powder is constant ; this is deter- 
 mined by a notch on the ramrod — the notch 
 being so arranged as to leave an interval between Fig. 10a 
 the powder and the bullet. 
 
 The diameter of this bullet is much less than that of 
 any other service; and, in consequence of its lightness, 
 it is fired with a larger proportional charge of powder. 
 Within the usual range of small arms, it is said to have 
 a flatter trajectory, and greater accuracy, than any other 
 small-arm projectile ; but at extreme ranges it loses its 
 velocity very rapidly. 
 
 CHARGE OF POWDER. 
 
 291. Conditions The proper charge of powder, for 
 a small-arm, depends on the calibre, windage, length of 
 barrel, weight of the piece, and character of the projec- 
 tile. The charge of the old smooth-bored musket was 
 
QUALITIES. 315 
 
 from one-half to one-third the weight of the projectile ; 
 this was necessary to make up for the loss of force by 
 great windage, and to give the round bullet the neces- 
 sary momentum. When the elongated bullet was in- 
 troduced, it became necessary to reduce the charge to 
 prevent too severe recoil ; besides, the mass of the bullet 
 being increased, a diminished velocity sufficed to pro- 
 duce the same effect. 
 
 In the case of expanding bullets, too small a charge 
 will be insufficient to force the lead into the grooves of 
 the barrel ; at the same time, it is shown by experience 
 that, if the charge be increased beyond a certain point, 
 the bullet is liable to be disfigured by upsetting, and its 
 accuracy is diminished. TJie proper charge for elongated 
 expanding bullets varies from one-tenth to one-seventh 
 the weight of the projectile. 
 
 LUBRICANT. 
 
 292. Necessity. After a fire-arm has been discharged 
 several times, the residuum of the burnt powder collects 
 on the surface of the bore, forming a hard substance 
 which seriously obstructs loading ; and unless the 
 windage be very great, it becomes necessary to wipe 
 out the bore, or apply some lubricating substance to the 
 projectile. 
 
 293. equalities. A proper lubricating substance for 
 small-arms should be unaffected by changes of climate ; 
 i. e., it should not be melted by hot, nor rendered too 
 hard by cold, weather ; it should not corrode the projec- 
 tile, nor weaken the paper of the cartridge, even when 
 
316 DIFFERENT KINDS OF SMALL- ARMS. 
 
 kept in store (as all ammunition is liable to be) for a 
 considerable length of time. 
 
 294. Methods*. The insertion of a few drops of water, 
 or oil, in the bore, has been tried with some success, but 
 the most common lubricating substance is beeswax, or 
 beeswax and tallow, applied to the projectile, or its 
 patch. Beeswax answers well in a hot climate, and, if 
 it be free from acid, does not act on the bullet, nor the 
 patch; tallow alone lubricates the bore well in all 
 climates, but it corrodes the lead of the projectile, and, 
 in the course of time, dries away. 
 
 The proportion used in the United States service is 
 four of beeswax to one of tallow, applied by dipping 
 the bullet into the melted substance, and immediately 
 withdrawing to cool. The bullet should be previously 
 w r armed, to prevent the substance from peeling off by 
 too rapid cooling. The rifle-musket can be thus fired 
 200 times, at least, without inconvenience. 
 
 DIFFERENT KINDS OF SMALI^ARMS. 
 
 The small-arms of the United States service are the 
 rifle-musket, rifle, carbine, &n& pistol. 
 
 295. Rifle-mu§ket. The present rifle-musket was 
 adopted in 1855, with a view of combining in one piece 
 the range and accuracy of the rifle with the advantages 
 of the musket, as regards lightness, quickness of loading, 
 and facility of handling as a pike. It is, therefore, the 
 appropriate arm of troops acting on foot, and in line. 
 
 Length of barrel, . . . 40.00 in. 
 Length of arm with bayonet, . .74.00 in. 
 Weight of barrel, . . . 4.25 lbs. 
 
CARBINE. 317 
 
 Weight of arm complete, . . 9.90 lbs. 
 Weight of projectile, . . . 550.00 grs. 
 
 Weight of powder, . . . 60.00 grs. 
 
 Initial velocity, .... 960.00 feet. 
 
 The cadet-musket only differs from the foregoing in 
 the length of its barrel and bayonet — the former being 
 38 in., and the latter 16 in. It would make a suitable 
 arm for light troops. 
 
 296. Rifle. The rifle differs from the rifle-musket in 
 having a shorter and stouter barrel, a sword-bayonet, 
 in the mountings, which are made of brass instead of 
 iron, and in having its barrel browned. 
 
 Length of barrel, . . . 33.00 in. 
 Length of arm with bayonet, . . 72.00 in. 
 Weight of barrel, . . . 4.80 lbs. 
 
 Weight of arm complete, . . 13.00 lbs. 
 Charge (projectile and powder), same 
 
 as in rifle-musket. 
 Initial velocity, .... 910.00 feet. 
 
 297. Carbine. The term carbine is applied to an arm 
 used by mounted troops, and intermediate in weight 
 and length between the rifle and pistol. Both breech 
 and muzzle loading carbines are employed, but the 
 former are generally preferred. The ramrod of the 
 muzzle-loading carbine is attached to the barrel by a 
 swivel, which permits it to be handled freely, but at the 
 same time prevents it from falling to the ground. The 
 carbine is secured to the person of the soldier by a 
 sling, which hooks on to a ring, moving on a swivel- 
 bar attached to the left side of the carbine, thereby 
 affording a play to the piece in loading and firing. 
 
318 DIFFERENT KINDS OF SMALL-ARMS. 
 
 Length of barrel, . . . 21.00 in. 
 
 Weight of piece, . . . . 7.50 lbs. 
 Weight of projectile, . . . 450.00 grs. 
 
 Weight of powder, . . . 55.00 grs. 
 
 Initial velocity, .... 820.00 feet. 
 
 298. Pi§toi-cari>ine. The pistol-carbine is a muzzle- 
 loading pistol, with a false butt, which permits it to be 
 used either as a pistol or carbine. It is particularly 
 suited to the service of light artillery. 
 
 Length of barrel, . . . 12.00 in. 
 Weight complete, .... 5.00 lbs. 
 Weight of projectile, . . . 450.00 grs. 
 Weight of powder, . . . 40.00 grs. 
 
 Initial velocity, .... 603.00 feet. 
 
 299. Coit'§ pi§toi. Colt's pistol is constructed on the 
 revolving principle, and is composed of a cylinder (con- 
 taining six charges), a rifled barrel, and a handle or 
 stock. By cocking the hammer, the cylinder is made to 
 rotate around a spindle in such a way that a new charge 
 is presented to the breech of the barrel every time the 
 piece is cocked. The principal defects of revolving pis- 
 tols are, that more than one charge is liable to go off at 
 a time ; that the fragments of the cap are liable to clog 
 the cylinder ; and that there is an escape of gas through 
 the opening in front of the cylinder. 
 
 The advantage is rapidity of fire for six discharges. 
 Colt's pistol is considered a very reliable weapon, par- 
 ticularly in partisan warfare. 
 
 Length of bore (navy), . . . 9.00 in. 
 
 Weight of do 2.40 lbs. 
 
 Weight of projectile, . . 125.00 grs. 
 
SPORTING RIFLE. 319 
 
 Weight of powder, . . . 14.00 grs. 
 Initial velocity, . . . 760.00 feet. 
 
 300. Sporting rifle. American sporting rifles have 
 long enjoyed a reputation for extreme accuracy of fire. 
 This has been attained by introducing into their con- 
 struction many refinements which, though ingenious 
 and effective, are incompatible with the strength, safety, 
 and rapidity of fire of a military arm. To give stiff- 
 ness and steadiness to the barrel, it is made very heavy 
 in proportion to the charge ; to prevent the bullet from 
 being disfigured by a heavy proportional charge of 
 powder, the calibre is made as small as the range will 
 permit ; to render friction in the bore uniform, the sur- 
 face is carefully wiped after each discharge ; to prevent 
 disfiguring the corners of the muzzle, the bullet is in- 
 serted into the bore through a false muzzle ; to centre 
 the bullet properly in the bore, it is started with an in- 
 strument called the straight starter; and, finally, the 
 piece is aimed with a globe, or telescopic sight, and 
 fired with a hair-trigger. 
 
 The dimensions, &c, of a James's rifle, of this class, 
 belonging to the museum of the Academy, are as fol- 
 lows, viz.: 
 
 Length of barrel, .... 32.50 in. 
 
 Weight of do 16.50 lbs. 
 
 Calibre, 00.45 in. 
 
 Weight of bullet, . . - 217.00 grs. 
 
 Weight of powder, .... 100.00 grs. 
 
 Initial velocity, .... 1,900.00 feet. 
 
320 MANUFACTURE OF SMALL- ARMS. 
 
 MANUFACTURE OF SMALL-ARMS. 
 
 301. Where made. With the exception of swords 
 and patent-arms, all small-arms for the United States 
 army and militia are made at the national armories, 
 situated at Springfield, Mass., and Harper's Ferry,* Ya. 
 These armories are under the general charge of the 
 chief of ordnance, who, by the authority of the war 
 department, furnishes the models, and prescribes the 
 kind and quantity of work to be done ; the operations 
 are conducted by civilians. 
 
 302. How made. A principal requisite, in the manu- 
 facture of small-arms, is, that similar parts of the same 
 kind of arm, or model, shall be capable of interchange. 
 This demands a higher degree of accuracy in the work- 
 manship than can be attained by hand-labor, without 
 great cost, and the consequence is, that machinery is 
 now very generally employed in this branch of man- 
 ufacture. 
 
 303. Operation**. The principal operations of manu- 
 facturing arms are welding, swaging, boring, turning, 
 drilling, tapping, milling 1 cutting and filing, grinding, 
 case-hardening, tempering, Midi polishing. Welding and 
 swaging are performed by blacksmiths ; the other oper- 
 ations, by armorers or finishers. 
 
 304. Welding. Welding is the process of uniting 
 certain metals by means of heat and pressure. To 
 bring the heated substances into perfect contact, the 
 joining surfaces should be freed from the coating of 
 
 ♦Since the first edition of this work was published, the Harper's Ferry armory 
 has been destroyed, and is no longer used for government purposes. 
 
ROLLING BARRELS. 321 
 
 oxide which generally covers them ; and this is done by 
 applying a composition of ten parts of borax to one of 
 sal-ammoniac. 
 
 The most important welds in the musket are those 
 of the barrel, and the blade and socket of the bayonet. 
 The first was formerly done under the trip-hammer; 
 it is now better and more economically performed by 
 rollers. 
 
 305. Roiling barrels. The material from which a 
 musket-barrel is made is a flat bar of wrought iron, 14 
 inches long, 5| inches wide, and T 9 T inches thick; the 
 edges are bevelled so that they will make a perfect lap- 
 joint when united as a tube. The several processes of 
 welding are curving, welding, and straightening. 
 
 Curving. The plate is heated in a reverberatory fur- 
 nace, to a red heat, and then passed between the grooves 
 of the curving-rolls (fig. 109), to bring the bevelled edges 
 
 in contact. There are five 
 grooves, two being open 
 
 grooves, and three have 
 tongues upon the upper 
 Fig. 109. roll to bend the plate 
 
 down into the lower groove. The grooves also differ 
 in size. The first one gives the plate the shape of a 
 trough; the second and third gradually contract it, 
 without changing its form; the fourth and fifth are par- 
 allel grooves, which bring the edges of the plate in con- 
 tact. The object of so many grooves is, to bend the plate 
 gradually, and prevent it from being split open, in case 
 the iron is brittle. In this way, 450 plates can be bent 
 by one set of rolls in a day. 
 
 Welding. The plates thus bent, or " cylinders" are 
 
 21 
 
322 MANUFACTUKE OF SMALL-AEMS. 
 
 replaced in the furnace to prepare them for the weld- 
 ing-rolls. The workmen are supplied with eight steel 
 mandrels, or rods terminated at the point with an egg- 
 shaped bulb; the bulbs vary from .71 in. to .46 in. in 
 diameter. When one of the cylinders is brought to a 
 white, or welding heat, a workman thrusts the largest 
 mandrel through it, whilst it is in the furnace. He 
 then carries it to the rolls (only one of which is shown 
 in fig. 110), and placing the mandrel through the frame, 
 he introduces the end of the cylinder into the first 
 groove; the action of the rolls is to slip the cylinder 
 over the mandrel, the centre of the bulb being placed 
 
 and held in the plane 
 
 
 of the axis of the two 
 rolls. The cylinder is 
 then straightened by 
 striking it on a flat 
 iron table, and placed 
 Fi &- uo in the furnace to be 
 
 reheated. The second size mandrel is then inserted, and 
 the cylinder is passed through the second groove in the 
 rolls, which is smaller than the first, and the welding is 
 completed. 
 
 The object of the remaining grooves is, to give the 
 proper form, or taper, to the cylinder, and for this pur- 
 pose they are made of the same shape as the required 
 barrel. As each groove makes a single circuit of the 
 rolls, and as the rolls are continually in motion, it re- 
 quires some dexterity on the part of the workman to 
 insert the end of the cylinder at the right moment. 
 
 In this way the cylinder is passed, breech foremost, 
 through five of the taper grooves; it is then passed 
 
DRILLING AND TAPPING. 323 
 
 twice through the last groove, without a mandrel, to 
 make it smooth. 
 
 In passing through each taper groove, the barrel is 
 reheated (to a red heat), as the bulb of the mandrel 
 chills the interior surface. 
 
 Straightening. The welding process being completed, 
 a workman places the barrel in the straightening ma- 
 chine, which is composed of two dies, each of the length 
 and shape of the half-barrel, and which close upon each 
 other as the workman turns the barrel around its axis 
 with a pair of tongs. 
 
 In this way about 75 barrels can be finished by one 
 set of workmen in a day. 
 
 306. Swaging. Swaging is the operation by which 
 the rough iron or steel is converted into a piece of suit- 
 able size and shape for the finisher. It is done by forc- 
 ing the piece of heated metal into a die by means of a 
 heavy drop-weight ; the machine is called a drop-hammer. 
 
 307. Boring. Boring is the operation of forming the 
 bore of the barrel. The manner of performing it, and 
 the character of the tools used, depend on the metal 
 employed. If it be steel, the piece to be bored is formed 
 into a solid bar, of homogeneous texture ; if of wrought 
 iron, it is formed into a tube, some portions of which 
 are liable to be harder and more difficult to cut than 
 others. In the first case, a stationary drill is driven 
 through the piece which revolves ; in the second case, 
 the boring instrument revolves rapidly, and, at the same 
 time, is drawn through the hole left by the welding 
 mandrel. 
 
 308. Drilling and tapping. The object of drilling is 
 to form holes for the screws, rivets, &c. ; and that of 
 
324 SMALL-ARMS. MANUFACTURE OF. 
 
 tapping, is to convert the surface of the hole into a fe- 
 male screw. The former operation is performed by the 
 drill-press ; the latter by an instrument called a tap, 
 which is made of a piece of steel, of a pyramidal form, 
 and on the edges of which are segments of screw 
 threads. In all operations of cutting and drilling 
 wrought iron, it is necessary to use oil or water to pre- 
 serve the temper of the tools. In working cast iron, no 
 cooling substance is required. 
 
 309. Turning. The object of turning is to give shape 
 and smoothness to the exterior of a body, and is accom- 
 plished in a machine called a lathe. The body is gen- 
 erally made to revolve around a fixed axis, and a cut- 
 ter, which has a motion parallel to this axis, is made to 
 press against its surface ; the combination of these two 
 motions cuts away a spiral chip, and leaves a new sur- 
 face concentric with the axis. It will be easily seen 
 that if the cutter has, in addition to its motion parallel 
 to the axis of rotation, another perpendicular to it, that 
 the resulting figure will be no longer round, but irregular. 
 
 This constitutes the principle of eccentric turning, and 
 affords the means of turning an almost infinite variety 
 of shapes, simply by regulating the motion of the cutter 
 by a pattern, or model of hardened steel. In this way 
 gun-stocks, and other irregular figures, are formed by 
 machinery ; the principle has even been used in copying 
 statuary. 
 
 310. Milling. Pieces of metal which are not suited 
 to the turning-lathe, may be reduced to their proper 
 shape by milling, an operation adapted to nearly all 
 surfaces which have rio*ht-line elements. 
 
 It is performed by a revolving cutter, armed with 
 
CASE-HARDENING. 325 
 
 saw-teeth, while the piece to be cut is fastened on a 
 carriage, which moves steadily under the cutter, and 
 along a plane director. 
 
 The shape of the cut surface depends on the shape 
 of the profile of the cutter ; for instance, to dress the 
 sides of a lock-plate, a cylindrical cutter would be used ; 
 to trim the edges, a curved one. By combining differ- 
 ent shaped cutters on the same arbor, or shaft, a great 
 variety of surfaces can be formed. 
 
 311. Cutting and filing. Cutting and filing are done 
 by the hand — the former with a cold-chisel, and the 
 latter by a file. They are employed to finish such parts 
 as are not well adapted to machinery. To guide the 
 workman in giving the proper form, the piece is placed 
 in a hardened steel frame, called ajeg. 
 
 312. Qrinding and polishing. Grinding is done with 
 rapidly-revolving grindstones, and is principally con- 
 fined to finishing the bayonet, and exterior of the 
 barrel. Polishing the surface of finished parts is done 
 with emery-wheels, which revolve with great rapidity. 
 The wheels are made of wood, and the circumference 
 is covered with buff leather, to which is glued a coat- 
 ing of emery. 
 
 313. Case-hardening. Case-hardening is the conver- 
 sion of the surface of wrought iron into steel, to enable 
 it to receive a polish, or bear friction. The process con- 
 sists in heating the iron to a cherry red, in a close vessel, 
 in contact with carbonaceous matter, and then plunging 
 it into cold water. Old shoes are generally employed 
 for this purpose at the armories, although bones, hoofs, 
 soot, &c, will answer. The materials should be first 
 burnt, and then pulverized. 
 
326 SMALL- ARMS. MANUFACTURE OF. 
 
 314. Hardening and tempering steel. Hardening is 
 effected by heating the steel to a cherry red, or until 
 the scales of oxide are loosened on its surface, and 
 plunging it into a liquid, as water, oil, &c., or placing 
 it in contact with some cooling solid; the degree of 
 hardness depends on the heat, and the rapidity of 
 cooling. Steel is thus rendered so hard as to resist 
 the hardest file; and it becomes at the same time ex- 
 tremely brittle. 
 
 Tempering. In its hardest state steel is too brittle 
 for most purposes; the requisite strength and elasticity 
 are obtained by tempering, which is done by heating 
 the hardened steel to a certain degree, and juunging it 
 into cold water. 
 
 The requisite heat is usually ascertained by the color 
 which the surface of the steel presents, due to the film 
 of oxide formed on it : 
 
 At 450° Fahr., a pale j Suitable for hard instruments, 
 
 straw color. { as the faces of hammers, &c. 
 
 f Gives a spring temper, or one 
 
 At 600° Fahr., a grey- J that will bend before break- 
 
 ish blue. j ing : suitable for saws, sword- 
 
 v blades, &c. 
 
 Shades of colors between these extremes, give inter- 
 mediate degrees of hardness. If steel be heated above 
 (300°, the effect of the hardening process is destroyed. 
 The parts of small arms are tempered by dipping them 
 in oil, then heating them until the oil is burned off, 
 when they are again plunged into cold water. 
 
 315. Blueing. A blue color may be given to the 
 surface of iron and steel parts, by subjecting them to a 
 
OBJECT OF INSPECTION. 327 
 
 certain degree of heat. As soon as the proper shade 
 of blue makes its appearance, the piece is removed and 
 allowed to cool, when the color becomes fast. 
 
 316. Browning. Browning is the coating given to 
 a gun-barrel to protect it from the action of the at- 
 mosphere, and to prevent the surface from reflecting the 
 sunlight. 
 
 The process consists in forming a coat of rust, with 
 a mixture of such materials as spirits of wine, blue 
 vitriol, tincture of steel, nitric acid, &c. (see Ord. Manl.), 
 on the clean surface of the barrel, and then rubbing it 
 well with a steel scratch-card until it has a metallic lus- 
 tre. This operation is repeated about a dozen times, 
 until the coating has a deep brown color. The barrel 
 is then washed with boiling water, to dissolve away any 
 of the corroding mixture that may remain, and, when 
 cold, is covered with sperm oil. 
 
 When the browning has been worn away in places, 
 it may be entirely removed — first, by boiling in lime- 
 water, to remove the varnish or grease, and then soak- 
 ing in vinegar, which loosens the browning so that it 
 can be wiped away with a rag. 
 
 INSPECTION OF SMALL-AKMS. 
 
 317. Object. The objects of inspecting small-arms 
 are, to verify the dimensions, the workmanship, and the 
 quality of the materials of the various parts. 
 
 Inspections at the armories are made by the foremen 
 of the several departments of work, under the direc- 
 tion of the master armorer. To secure uniformity in 
 
328 SMALL- ARMS. INSPECTION OF. 
 
 all service-arms, comparative inspections are occasionally 
 made of the work from the different armories ; the parts 
 of one set are required to interchange freely with those 
 of another. Partial inspections are made at the dif- 
 ferent stages of manufacture, to prevent unnecessary 
 labor from being expended on defective pieces. Con- 
 tract-arms are inspected by an officer of the ordnance 
 department, and by sworn assistants taken from one of 
 the armories. 
 
 The following regulations for the inspection of fin- 
 ished arms, the care and preservation of arms in service, 
 &c, are taken from the Ordnance Manual. 
 
 318. Fini§iied arm. The inspector will examine the 
 finished arm on every side, to see that the parts are well 
 fitted together ; he will also verify the principal dimen- 
 sions and forms, by means of appropriate gauges and 
 patterns. 
 
 319. Barrel. The diameter of the bore should be 
 verified with the standard and limit gauges. The stand- 
 ard gauge is a cylinder of the diameter of the bore 
 (.58 in,), and the limit gauge is .0025 inch greater. 
 The former should pass freely through the bore, and the 
 latter should not enter it. The barrel should enter the 
 groove of the stock, one-half of its diameter, and should 
 bear uniformly throughout, particularly at the breech. 
 The vent should be accurate in its dimension, position, 
 and direction, and a wire should be passed through it, 
 to s'ee that it is free. The cone should be sound. The 
 shoulders of the breech-screw should fit close to the end 
 of the barrel, and it should be free from cracks or flaws 
 about the tang-screw hole. The straightness of the 
 barrel may be ascertained by turning out the breech- 
 
stocks. 329 
 
 screw, and holding the barrel up to the light, and re- 
 flecting the image of a straight-edge from the surface of 
 the bore. If the barrel be straight, the reflected image 
 will be straight in all positions of the barrel. The 
 bore should be free from hammer-marks, ring-bores, cin- 
 der-holes, flaws, cracks, &c, and the bayonet-stud and 
 sight notches, should not be cut too deep. 
 
 320. Ramrod. The temper of the ramrod may be 
 tested by springing it in four directions, with the point 
 resting on the floor. When the musket-rod is bent 
 six inches out of line, it should spring back perfectly 
 straight without setting. Its soundness may be tested 
 by striking it with a piece of metal, or by bending it 
 over the edge of a block of wood; in the first case the 
 sound emitted should be clear, and in the second case 
 the flaws or cracks will be opened. The screw on the 
 point of the rod should be properly cut ; it should bear 
 properly in its groove, neither too light, nor too loose. 
 The point should rest on the stop. 
 
 321. Bayonet. The form and dimensions of the bay- 
 onet are verified with the proper gauges ; the temper 
 is tried by resting the point against the floor, and spring- 
 ing the blade smartly in four directions — toward the 
 back, face, and two edges — grasping the butt of the 
 stock with the right hand, and the middle of the bar- 
 rel with the left. After this, inspect for cracks and 
 flaws. To test the welding of the blade to the socket, 
 strike the elbow smartly on the work-bench. 
 
 322. stock§. The wood should be straight-grained, 
 well-seasoned, and free from sap and worm-holes. The 
 effect of unseasoned wood will be to rust the lock and 
 barrel. It may be detected by the odor of a fresh cut, 
 
330 SMALL-ARMS. PACKAGE AND STORAGE OF. 
 
 or by the crumbling of a chip when pressed in the fin- 
 gers. The edges should be sharp and clear, and free 
 from splits. The dimensions, which concern the fitting 
 of the parts, should be carefully verified. 
 
 323. l.ock. All parts of the lock should be sound, 
 well filed, and of proper form and- dimensions. The 
 temper of the hardened parts should be tried with a 
 fine-cut file. See that the main and sear springs have 
 the requisite power. 
 
 Examine carefullv the action of the lock; see that 
 the movable parts are free, i.e., do not rub against other 
 parts when in motion. Snap on the cone, and see that 
 it fits its seat properly. Let the hammer down several 
 times, to judge of the working of the parts. See that 
 the interior parts are not wood-bound ; that it does not 
 go off at half-cock when the trigger is pulled hard, and 
 that it goes neither too hard nor too easy when cocked. 
 
 324. mountings The trigger should work freely, but 
 should have no lateral motion in the guard-plate. The 
 guard-plate should not be screwed up too hard, lest the 
 trigger be brought too close to the sear. The bands 
 should be close to the stock, but not so tight as to re- 
 quire much force to move them. The band-springs 
 should spring back freely when pressed down. 
 
 The sights are aligned by the flats of the barrel, which 
 are equidistant from the axis of the bore, by construc- 
 tion. The alignment can only be verified by firing at 
 a target. 
 
 « 
 
 PACKING AND STORAGE OF ARMS. 
 
 325. Boxes. Packing-boxes for muskets are made of 
 
STORAGE. 331 
 
 well-seasoned pine boards. Each box contains twenty 
 muskets, in two rows of ten each. The pieces are kept 
 from jostling and injuring each other by grooved clamps. 
 The bayonets are unfixed, and placed securely on the 
 bottom of the box, and the appendages are placed in a 
 small apartment at the end. 
 
 When the regular packing-box cannot be had, arms 
 may be packed in boxes with straw that is dry and free 
 from dust, by forming it into a rope, and wrapping it 
 around them; hay will not answer. They are then 
 placed in rows, the lower row resting on three cushions 
 of .straw placed on the bottom. The butts are kept 
 apart by wedges of straw ; and the top row is covered 
 with straw, pressed in by the cover, which is fastened 
 by two hoops. 
 
 326. storage. Arms are kept at the arsenals either in 
 the boxes in which they are received from the armories, 
 or in racks. 
 
 Each kind is kept separate, and arranged according 
 to model, the place and year of construction, and the 
 time when they were last cleaned. 
 
 New arms are kept distinct from those which have 
 been repaired. Arms of peculiar kinds, arms to be 
 repaired, and unserviceable or condemned arms, are 
 kept separate. 
 
 Limbs and spare parts, intended for repairs of arms, 
 should be kept in store by themselves, in a dry place, 
 classed according to the kind of arms, and to the model 
 and year of fabrication, and labelled accordingly. 
 
 All arms in store should be frequently examined, to 
 see that they are not rusty. Those which are rusty 
 should be immediately cleaned and oiled with sperm 
 
332 SMALL- ARMS. PRESERVATION AND CARE OF. 
 
 oil. If browned arms are affected with specks of rust, 
 they should be rubbed with linseed oil ; and if the 
 acid be not neutralized, proper authority should be 
 obtained to remove and renew the browning. Empty 
 packing-boxes, from which the arms in racks are taken, 
 should be kept, with the necessary parts, in the attics, 
 or other dry situations. Storehouses for arms should 
 be aired in clear, dry weather. 
 
 PRESERVATION AND CAEE OF ARMS IN 
 SERVICE. 
 
 327. in§truction. The officers, non-commissioned offi- 
 cers, and soldiers, should be instructed and practised in 
 the nomenclature of the arms, and the manner of dis- 
 mounting and mounting them, and the precautions and 
 care required for their preservation. 
 
 Each soldier should have a screw-driver and a wiper, 
 and each non-commissioned officer a wire tumbler-punch 
 and a spring-vice. No other implements should be 
 used in taking arms apart, or in setting them up. 
 
 In the inspection of arms, officers should attend to 
 the qualities essential to service, rather than to a bright 
 polish on the exterior. Arms should be inspected in 
 the quarters, at least once a month, with the barrel and 
 lock separated from the stock. 
 
 328. Dismounting by a soldier. The rifle-musket 
 should be dismounted in the following order, viz. : — 1st. 
 Unfix the bayonet ; 2d. Insert the tompion ; 3d. Draw 
 the ramrod ; 4th. Turn out the tang-screw ; 5th. Take 
 off the lock ; to do this, put the hammer at half-cock, 
 and partially unscrew the side-screws, then, with a slight 
 
TO CLEAN THE BARREL. 333 
 
 tap on the head of each screw with a wooden instru- 
 ment, loosen the lock from its bed in the stock ; turn 
 out the side-screws, and remove the lock with the left 
 hand ; 6th. Remove the side-screws without disturbing 
 the washers; 7th. Take off the bands in order, com- 
 mencing with the uppermost ; 8th. Take out the bar- 
 rel. In doing this, turn the musket horizontally, with 
 the barrel downward, holding it loosely, with the left 
 hand below the rear sight, and the right hand grasping 
 the stock by the handle ; tap the muzzle on the ground, 
 if necessary, to loosen the breech. If an attempt were 
 made to pull the barrel out by the muzzle, it would, in 
 case it were wood-bound, be liable to split at the head 
 of the stock. 
 
 The foregoing parts of the rifle-musket are all that 
 should usually be taken off, or dismounted by the sol- 
 dier. The breech-screw should be taken out only by an 
 armorer, and never in ordinary cleaning. The mount- 
 ings, cone, and cone-seat screw, should not be taken off, 
 nor should the lock be taken apart, except by permis- 
 sion of an officer. 
 
 329. To clean the barrel. 1st. Stop the vent with a 
 peg of soft wood, or piece of rag or soft leather pressed 
 down by the hammer ; pour a gill of water (warm, if it 
 can be had) into the muzzle ; let it stand a short time, 
 to soften the deposit of powder; put a plug of soft 
 wood into the muzzle, and shake the water up and 
 down the barrel ; pour it out, and repeat the washing 
 until the water comes out clear ; remove the peg from 
 the cone, and stand the barrel, muzzle downward, to 
 drain, for a few moments. 
 
 2d. Screw the wiper on the end of the ramrod, and 
 
334 SMALL-ARMS. PRESERVATION AND CARE OF. 
 
 put a piece of dry doth, or tow, round it, sufficient to 
 prevent it from chafing the grooves of the "barrel ; wipe 
 the barrel dry, changing the cloth two or three times. 
 
 3d. Put no oil into the vent, as it will clog the pas- 
 sage, and cause the first primer to miss fire ; but, with 
 a slightly oiled rag on the wiper, rub the bore of the 
 barrel, and the face of the breech-screw, and immedi- 
 ately insert the tompion into the muzzle. 
 
 4th. To clean the exterior of the barrel, lay it flat on 
 a bench or board, to avoid bending it. The practice of 
 supporting the barrel at each end, and rubbing it with 
 a strap, buffstiek, ramrod, or any other instrument, to 
 burnish it, is pernicious, and should be strictly forbidden. 
 
 5th. After firing, the barrel should always be washed 
 as soon as practicable ; when the water comes off clear, 
 wipe the barrel dry, and pass into it an oiled rag. Fine 
 flour of emery cloth is the best article to clean the exte- 
 rior of the barrel. 
 
 330. To clean the lock. Wipe every part with a 
 moist rag, and then a dry one ; if any part of the inte- 
 rior shows rust, put a drop of oil on the point or end of 
 a piece of soft wood dipped into flour of emery; rub 
 out the rust, and wipe the surface dry ; then rub every 
 part with a slightly oiled rag. 
 
 331. To clean the mountings. For iron and steel 
 parts, use fine emery moistened with oil, or emery cloth. 
 For brass parts, use rotten-stone moistened with vinegar 
 or water, applied with a rag, brush, or stick; oil or 
 grease should be avoided. The dirt may be removed 
 from the screw-holes by screwing a piece of soft wood 
 into them. Wipe all parts with a linen rag, and leave 
 the parts slightly oiled. 
 
lock. 335 
 
 332. Dismounting by an armorer. The parts which 
 are specially assigned to be dismounted by an experi- 
 enced armorer will be stated in their regular order, fol- 
 lowing No. 8, viz. : 
 
 9th. Unscrew cone ; 10th. Take out cone-seat screw ; 
 11th. Take out band-springs, using a wire punch ; 12 th. 
 Take out the guard-screws. Be careful that the screw- 
 driver does not slip, and mar the stock; 13th. Remove 
 the guard without injuring the wood at either end of 
 the plate ; 14th. Remove the side-screw washers with a 
 drift-punch; 15th. Remove the butt-plate; 16th. Re- 
 move the rear-sight ; 17th. Turn out the breech-screw 
 by means of a " breech-screw wrench" suited to the 
 tenon of the screw. No other wrench should ever be 
 used for this purpose, and the barrel should be held in 
 clamps, neatly fitting the breech. 
 
 333. L.ock. To take the lock apart : — 1st. Cock the 
 piece, and apply the spring-piece to the mainspring ; 
 give the thumb-screw a turn sufficient to liberate the 
 spring from the swivel and mainspring notch ; remove 
 the spring; 2d. The sear-spring screw; 3d. The sear- 
 screw and sear ; 4th. The bridle-screw and bridle ; 5th. 
 The tumbler-screw; 6th. The tumbler. This is driven 
 out with a punch, inserted in the screw-hole, which at 
 the same time liberates the hammer ; 7th. Detach the 
 mainspring swivel from the tumbler with a drift -punch; 
 8 th. Take out the feed-finger and spring ; 9th. The catch- 
 spring and screw. 
 
 As a general rule, all parts of the musket are assem- 
 bled in the inverse order in which they are dismounted. 
 Before replacing screws, oil them slightly with good 
 sperm oil (inferior oil is converted into a gum which 
 
336 SMALL- ARMS. INSPECTION OF, ETC. 
 
 clogs the operation of the parts). Screws should not be 
 turned in so hard as to make the parts bind. When a 
 lock has, from any cause, become gummed with oil and 
 dirt, it may be cleaned by boiling in soap-suds or in 
 pearlash or soda water ; heat should never be applied in 
 any other way. 
 
 334. Precautions in using. In ordering arms on 
 parade, let the butt be brought gently to the ground, 
 especially if the ground be hard. This will save the 
 mechanism of the lock from shocks, which are very in- 
 jurious to it, and which tend to loosen and mar the 
 screws, and split the woodwork. 
 
 The ramrod should not be " sprung" with unnecessary 
 force, for fear of injuring the corners of the grooves ; 
 and, in stacking arms, care should be taken not to in- 
 jure the bayonets by forcibly straining the edges against 
 each other. 
 
 No cutting, marking, or scraping the wood or iron 
 should be allowed ; and no part of the gun should be 
 touched with a file. Take every possible care to pre- 
 vent water from getting between the lock, or barrel, 
 and stock. If any should get there, dismount the gun 
 as soon as possible, clean and oil the parts as directed, 
 and see that they are perfectly dry before assembling 
 them. 
 
 INSPECTION OF ARMS IN SERVICE, &c. 
 
 335. Gauges. The inspecting instruments are the 
 standard and limit gauges of the bore and exterior of 
 the barrel, and a screw-plate with taps for the holes of 
 the lock-plate. 
 
CLASSIFICATION. 3o7 
 
 336. inspection. The following are the principal 
 points to be attended to in the inspection : 
 
 Barrel. Defects for which the barrel must be con- 
 demned as unfit for service. The large gange entering 
 the whole length of the barrel. The small or standard 
 gauge not entering, unless the diminution of the bore 
 is caused by the barrel being indented or bent, defects 
 which may be remedied. A diminution of the exterior 
 diameter at the breech, or at the muzzle, so as to enter 
 the small receiving gauges ; this diminution is 0.1 inch 
 at the breech ; 0.03 inch at the muzzle, for arms with 
 bayonets ; 0.045 inch for arms without bayonets. A 
 diminution of 0.5 in length of the barrel, splits, cross- 
 cracky an 1 other serious defects, caused either by bad 
 workmanship, or by use. 
 
 See that the bayonet-stud is not too much worn or 
 broken ; that the cone-seat is perfect, and the vent un- 
 obstructed. See that the breech-screw is tight after 
 entering five or six threads ; that the threads are sharp 
 and sound ; that the body fills the bore of the female 
 screw; that the tang is not broken or cracked at the 
 screw-hole, and that it is even with the upper surface 
 of the barrel. If it have any of these defects, replace 
 it with a new one. 
 
 Cone. See that the chamfered end is not broken or 
 bruised, and that the thread and vent are in proper 
 condition. 
 
 Bayonet. A bayonet is considered unserviceable if 
 the blade is one inch too short. See that it is sound and 
 perfect in all its parts; that it fits the barrel; and that 
 the clasp is in good order, and turns freely. 
 
 Lock. See if the fixed branches of the springs fit 
 
 22 
 
338 
 
 closely to the lock-plate, if the movable branches are 
 clear of it, and if any of the parts are wood-bound. 
 Renew the springs and the bridle of the tumbler when 
 their pivots are broken. If the sear rubs on the plate, 
 have it adjusted. The friction of the tumbler may be 
 caused by the bridle being badly pierced, in which 
 case renew the bridle. If the hammer rubs on ono 
 side, have it adjusted; if it rubs everywhere, the ar- 
 bor of the tumbler does not project sufficiently, and 
 the tumbler should be renewed. If the notches of the 
 tumbler are broken, or the edges blunt, have them 
 dressed; if the hook of the tumbler projects beyond 
 the edge of the lock-plate when the hammer is let 
 down, the tumbler should be renewed. The arbor and 
 pivot of the tumbler should fit well in their holes. Ex- 
 amine the sear closely, and have it renewed when the 
 nose is too thin, or is worn on the side next the lock- 
 plate, although it may be perfect on the exterior.- 
 
 If the hammer is not steady, the tumbler should be 
 renewed. Try the action of the hammer, to see that it 
 explodes the cap with certainty. 
 
 Renew the lock-plate when the screw-holes are too 
 much, worn to be dressed over. Renew every limb 
 that is broken or cracked, the screws which are too 
 much worn, or of which the stems are bent, or the slits 
 too much enlarged. 
 
 Mountings, See if the parts be complete and sound. 
 
 Ramrod. See if it be sound, and have a good 
 thread, and be of the proper length; otherwise re- 
 place it. 
 
 Stock. Examine carefully the bed of the loch, and the 
 holes for the band and springs. Press the thumb against 
 
DURABILITY. 339 
 
 the facings, to see if they are split at the holes for the 
 side-screws, and renew the stock if it be split at any 
 other part to an injurious extent. 
 
 337. cia§siflcation. Arms that have been in service 
 may be classified as follows : 
 
 1st. Serviceable arms, 
 
 2d. Arms requiring repairs. 
 
 3d. Irreparable arms. 
 
 Arms in the hands of the troops may be repaired 
 by replacing the defective parts by new ones, or by 
 transferring parts from other arms of the same model. 
 Every officer in charge of arms should be supplied with 
 a suitable number of spare parts for making repairs in 
 the field. 
 
 Arms are considered irreparable when both the bar- 
 rel and stock are unfit for service ; or when they require 
 extensive repairs, and the parts can be used for repairing 
 other arms. 
 
 DURABILITY AND STRENGTH OF THE 
 MUSKET-BARREL. 
 
 338. Durability. Some idea may be formed of the 
 endurance of small-arms generally, by that of the French 
 musket-barrel — the barrel being the most important 
 part of any arm. It has been shown that this barrel 
 will bear 25,000 discharges without becoming unser- 
 viceable. In time of war a musket is not fired more 
 than five hundred times a year ; with good care, there- 
 fore, it ought to last fifty years. 
 
 The principal cause of weakness in a barrel is the 
 diminution of the exterior diameter, at the breech, by 
 
340 SMALL- ARMS. STRENGTH. 
 
 wear. This diminution is limited to 0.1 inch, although 
 a barrel worn away 0.13 in. has borne the discharge of 
 two cartridges, placed one upon the other. 
 
 339. strength. Trials made at Mutzig, in 1829, with 
 arms sent there for repairs, show the following results : 
 
 1st. When a musket-barrel is charged with a single 
 cartridge placed in any part of the barrel, or with two, 
 or even three cartridges, inserted regularly, without 
 any interval between them, there is no danger; with 
 four cartridges, inserted regularly over each other, or 
 with two or three cartridges placed over each other 
 with slugged balls, there is danger only in case of some 
 defect of construction, or some deterioration in the 
 barrel ; with more than four cartridges inserted regu- 
 larly over each other, or with two, three, or four car- 
 tridges, with intervals between them, it is not safe to 
 fire. Late experiments with the rifle-musket, show that 
 any number of cartridges can be placed one upon the 
 other, and the piece be fired, without injury. In con- 
 sequence of the expansive nature of the projectile, 
 which cuts off the passage of the flame, but two charges 
 will be inflamed, and their force will be expended 
 through the vent. 
 
 2d. No danger of bursting is occasioned by leaving 
 a ball-screw in the barrel. There may, be danger from 
 a plug of wood driven tightly into the muzzle when 
 the barrel is loaded with two cartridges ; or from a cork 
 rammed into the barrel to a certain distance from the 
 charge, with another cartridge over it. 
 
 Snow, clay, and sand, accidentally introduced into 
 the barrel, are not dangerous, if they lie close to the 
 charge ; but they are so when there is a space between 
 
STRENGTH. 341 
 
 them and the charge ; in this case sand is the most dan- 
 gerous, then clay and snow. Balls or pieces of iron 
 inserted over the charge, are not attended with dan- 
 ger when placed close to it, even when their weight 
 amounts to 1} lbs. ; but there is danger from a piece of 
 iron 0.5 inch square, weighing J- lb., if placed 20 inches 
 or more from the breech. 
 
 3d. A barrel, with a defect which might have escaped 
 the inspector, bore the explosion of three cartridges, 
 regularly inserted. In these trials, barrels originally 
 0.272 inch thick at the breech did not burst when 
 loaded with two cartridges, until the thickness was 
 reduced to 0.169 inch, and with one cartridge, to 0.091 
 inch. 
 
342 PYROTECHNY. BUILDINGS, ETC. 
 
 CHAPTER VII. 
 PYROTECHNY. 
 
 340. Definition. Pyrotechny is the art of preparing 
 ammunition and fireworks for military and ornamental 
 purposes. It will be treated under the head of build- 
 ings, materials, ammunition, military fireworks, and 
 ornamental firework*. 
 
 BUILDINGS, &c. 
 
 341. How arranged. To conduct the operations of 
 a military laboratory with safety and convenience, the 
 following rooms are necessary, viz. : — 
 
 1st. Furnace-room, for operations requiring the use 
 of fire. 
 
 2d. Cartridge-room, for making all kinds of car- 
 tridges. 
 
 3d. Filling-room, for filling cartridges with powder. 
 
 4th. Composition-room, for mixing compositions. 
 
 5th. Driving-room, for driving rockets, fuzes, cfec. 
 
 6th. Packing-room, for putting up articles for trans- 
 portation. 
 
 7th. Carpenters and tinners shop. 
 
 8th. Magazine, for storing powder and ammunition. 
 
 A laboratory, like a powder-mill, should be situated 
 apart from inhabited buildings ; and, for convenience 
 of communication, the rooms, with the exception of the 
 
PRECAUTIONS. 343 
 
 farnace-room, carpenter's shop, and magazine, should be 
 situated under one roof. 
 
 342. Furnaces. A furnace is composed of a cast-iron 
 kettle, 2 feet in diameter, set in a fire-place of brick. In 
 the field, sods may replace the brick, if the latter cannot 
 be obtained. 
 
 Two kinds of furnaces are employed in a laboratory ; 
 in the first, the flame circulates around both bottom and 
 sides of the kettle ; in the second, it only comes in con- 
 tact with the bottom ; the latter is used for composi- 
 tions in which gunpowder forms a part. 
 
 343. Precautions. To prevent accidents in the oper- 
 ations of a laboratory, avoid, as much as possible, the 
 use of iron in the construction of the buildings, fixtures, 
 <fcc. ; sink the heads of iron nails, if used, and cover 
 them with putty; cover the floor with oil-cloth, or car- 
 pets, and have it frequently swept. Let the workmen 
 in the powder-room wear socks, and take them off when 
 they go out. Keep no more than the requisite quantity 
 of powder in the laboratory, and have the ammunition 
 and finished work taken to the magazine. Let powder- 
 barrels be carried in hand-barrows made with leather, 
 or with slings of rope or canvas, and the ammunition in 
 boxes. Let every thing that is to be moved be lifted, 
 not dragged or rolled on the floor. Never drive rockets, 
 port-fires, &c, in a room where there is any powder or 
 composition, except that used at the time. Never enter 
 the laboratory at night, unless it is indispensable, and 
 then use a close lantern, or wax or oil light well trim- 
 med. Allow no tobacco to be smoked, nor friction 
 matches to be carried in or around the laboratory. 
 
344 PYROTECHNY. MATERIALS. 
 
 MATERIALS. 
 
 344. Classified. Laboratory materials may be divided 
 into four classes, viz. : 
 
 1st. Those for producing light, heat, and explosion. 
 2d. Those for coloring flames, and producing brilliant 
 sparks. 
 
 3d. Those used in preparing compositions. 
 
 4th. Those used in making cartridge-bags, cases, &,c. 
 
 345. 1st. class. Nitre. For laboratory use, nitre 
 must be reduced to a fine powder, or very minute crys- 
 tals. It is best pulverized in rolling-barrels at the 
 powder-mills, but it may be pulverized by hand, in the 
 laboratory, with a rolling-barrel, or by pounding in a 
 brass mortar, or by stirring a crystallizing solution. 
 
 Chlorate of potassa. Chlorate of potassa is formed by 
 passing a current of chlorine, in excess, through lime- 
 water, and then treating the mixture with the chloride 
 of potassium, or by the carbonate or sulphate of potassa. 
 The chlorate of potassa and chloride of calcium are 
 formed — the former crystallizes, the latter remains in 
 solution. It is soluble in water, but not sensibly so in 
 alcohoL As before stated, it is a more powerful oxydiz- 
 ing agent than nitre ; and, when mixed with a combus- 
 tible body, easily explodes by shock or friction. It is 
 inflamed by simple contact with sulphuric acid, and 
 thus affords a simple means of exploding mines. 
 
 A convenient form of apparatus for this purpose, is 
 a glass vessel with two compartments, one containing 
 sulphuric acid, and the other chlorate of potassa and 
 gunpowder. It is placed near the surface of the ground, 
 
FIRST CLASS. 345 
 
 and, when broken under the feet of the enemy, the two 
 substances are brought in contact, producing fire, which 
 explodes the mine. 
 
 Charcoal. For laboratory use, charcoal may be made 
 by charring wood in an iron kettle buried in the ground. 
 It may be pulverized by rolling in a barrel with bronze 
 balls, or by beating in a leather bag with . a maul. It 
 should be kept in close barrels, in a dry place. 
 
 Sulphur. When melted sulphur is to be used, care 
 must be taken that it does not become thick, which oc- 
 curs at about 400°. It may be pulverized in a rolling- 
 barrel, or by being pounded in a mortar and sifted. 
 Roll brimstone is better for melting than flowers of sul- 
 phur. When flowers of sulphur are to be mixed with 
 chlorate of potassa, it should be washed to remove the 
 free sulphuric acid. Sulphur retards the combustion of 
 compositions to which it is added. 
 
 Antimony. Antimony, or regulus of antimony, is a 
 grayish white metal, easily reduced to a powder, and, 
 by its combustion with sulphur, produces strong light 
 and heat ; the color of the flame is a faint blue. 
 
 Sulphuret of antimony. Sulphuret of antimony is 
 mixed with inflammable substances to render them more 
 easily ignited by flame or friction. 
 
 Gunpowder. For compositions, gunpowder is pul- 
 verized, or mealed, by the rolling-barrel, or by grind- 
 ing with a muller on a mealing-table, or by beating in 
 a leather bag. The simple incorporation of the ingre- 
 dients of gunpowder does not answer the desired pur- 
 pose. 
 
 Lampblack. Lampblack is the result of the incom- 
 plete combustion of resinous substances. It is com- 
 
346 PYROTECHNY. MATERIALS. 
 
 posed of about 80 parts of carbon, and 20 of impurities. 
 It is employed to quicken the combustion of certain 
 mixtures; but, before it is used, it should be washed 
 with a hot alkaline solution, to remove all traces of em- 
 pyreurnatic oil. 
 
 346. 2d cia§s. Coloring materials. A flame is colored 
 by introducing into the composition which produces it, 
 a substance, the particles of which on being interspersed 
 through the flame, and heated to the incandescent state, 
 give it the required color. Coloring substances do not 
 generally take part in the combustion, and their pres- 
 ence, more or less, retards it ; it is for this reason that 
 chlorate of potassa, a more powerful oxydizing agent 
 than nitre, is used in lieu of it, in compositions for 
 colored fires. 
 
 Colors. There are a great variety of substances 
 which give color to flames, the principal of which are, 
 nitrate and sulphate of strontia and chloride of stron- 
 tium, for red ; the nitrate of baryta, for green ; the bi- 
 carbonate of soda, for yellow: the sulphate, carbonate, 
 and acetate of copper, for blue. Lampblack is employed 
 to give a train of rose-colored fire in the air, powdered 
 flint-glass for white flames, and oxide of zinc for blue 
 flames. 
 
 Sparks. Brilliant sparks are produced by introducing 
 into the composition, filings or thin chips of either 
 wrought iron, cast iron, steel, or copper, or by frag- 
 ments of charcoal ; the effect depends on the size of the 
 particles introduced. The particles should be freshly 
 prepared, or should have been well preserved from rust. 
 
 347. 3d Class. Preparing compositions. Turpentine 
 is the substance which exudes from the freshly-cut sur- 
 
PREPARING CARTRIDGES, ETC. 347 
 
 face of a pine tree in warm weather. The first year's 
 running is called virgin, or white turpentine j after this 
 it becomes more hard and yellow. 
 
 Spirits of turpentine. This is the essential oil ob- 
 tained by distilling native turpentine. 
 
 Rosin. This substance is sometimes called colophony, 
 and is the residuum of the distillation of turpentine. 
 
 Tar. Tar is a semi-fluid substance, obtained from the 
 heart of the pine-tree by a smothered combustion, as in 
 charcoal pits. 
 
 Pitch. Pitch is obtained by boiling tar down to the 
 requisite consistency, either by itself, or combined with 
 a portion of rosin ; it becomes solid on cooling, but is 
 softened by the heat of the hand. 
 
 Venice turpentine. Venice turpentine is obtained 
 from the larch ; but what is commonly known by that 
 name, is a compound of melted rosin and spirits of tur- 
 pentine. The foregoing substances are chiefly employed 
 in the preparation of compositions for producing light. 
 
 Alcohol, &c. Alcohol (spirits of wine), brandy, 
 whiskey, or vinegar, is used for mixing compositions in 
 which nitre enters, because this salt is but slightly sol- 
 uble in these liquids. 
 
 Gum-arabic. Gum-arabic in solution is employed to 
 give body to certain compositions. It retards combus- 
 tion ; and, as the solution is liable to spontaneous de- 
 composition, it should only be prepared as wanted. 
 
 Beeswax and mutton tallow are employed chiefly in 
 mixing compositions intended to produce heat and light. 
 
 348. 4th Class. Preparing cartridges &c. The size and 
 
 strength of laboratory paper is regulated by the use to 
 which it is applied. It is arranged in live classes, the 
 
348 PYEOTECHNY. AMMUNITION FOE SMALL- AEMS. 
 
 strongest being for cannon-cartridges, and the thinnest 
 for musket-cartridges. 
 
 Paste. Ordinary paste is made of rye flour, stirred 
 and boiled in water. 
 
 Flannel, wildbore, or serge, for cartridge-bags, should 
 be made entirely of wool or silk ; the fabric should be 
 soft, and closely woven, to prevent the powder from 
 sifting out. 
 
 Fabrics of cotton and flax are not used, because the 
 powder sifts through them, and they are more apt to 
 leave fire in the gun than woollen stuffs. 
 
 Canvas. Canvas is used for sacks, &c. ; it should be 
 strong and closely woven. 
 
 Twine, &c. Twine should be strong, smooth, and 
 well twisted. 
 
 AMMUNITION FOR SMALL-ARMS. 
 
 349. Bullets. Bullets, for the military service, are 
 made by pressure. To prepare the lead for the press, it 
 is cast into cylinders, or drawn out into a wire of a 
 diameter somewhat less than that of the bullet. A 
 piece, just sufficient to make a bullet, is then cut off, 
 and transferred by a movable arm to 
 a pair of dies (a a, fig. Ill), which 
 are firmly closed by two' movable 
 wedges (b i) ; as soon as this is done, 
 the punch (e) descends upon the 
 lead and forms the cavity at the base Fig. in. 
 
 of the bullet. To disengage the bullet, the punch rises, 
 but before it has completely cleared the cavity, the dies 
 open, and the bullet falls into its receptacle. 
 
PACKING. 
 
 349 
 
 One press is capable of making 3,000 bullets in an 
 k hour. Bullets may be also cast in moulds, and after- 
 ward swaged in a die to the proper size and shape. 
 
 350. Cartridge. After the bullet has been greased 
 (see page 315), it is made up into a cartridge along 
 with its charge of powder. The rifle-musket cartridge 
 (fig. 112) is formed of three parts; the bullet (£), the 
 cylinder («), w T hich contains the powder, and the wrap- 
 per, which unites the cylinder with the bul- 
 let. The bottom of the cylinder should be 
 perfectly tight, to prevent the powder from 
 sifting through. 
 
 To use this cartridge, tear off the fold of 
 the wrapper and pour the powder into the 
 bore, break the cartridge at the junction of 
 the bullet and powder-cylinder, force out Fig 112. 
 the bullet by pressing with the thumb and forefinger, 
 and insert it in the bore. Care should be taken to pour 
 all of the powder into the barrel. 
 
 351. Buckshot cartridge. The number of projec- 
 tiles in a buckshot cartridge is twelve, or four layers of 
 three each (fig. 113). The layers are kept in 
 position by passing one half hitch of the chok- 
 ing thread, between every two layers; the 
 thread is secured by passing two half-hitches 
 around the upper layer. For rifled arms, the 
 shot end of the cartridge should be dipped in 
 the composition used for lubricating bullets ; 
 with this precaution all leading of the grooves Fig. 
 will be avoided. Buckshot cartridges are principally 
 used in Indian warfare, and especially in night-firing. 
 
 352. Packing. Small-arm cartridges are wrapped in 
 
350 PYROTECHNY. AMMUNITION FOR SMALL- ARMS. 
 
 bundles of ten each, and packed in boxes of 1,000. The 
 date and place of fabrication are marked on the inside 
 of the cover, and the contents, on the outside of one end 
 of the packing-box. 
 
 353. Pistol cartridge. The powder-cylinder of Colt's 
 cartridge is made of combustible paper (prepared after 
 the manner of gun-cotton) ; it is attached to the base of 
 the bullet, and is inserted in the piece entire. 
 
 354. Percussion-caps. The military percussion-cap 
 is made slightly conical, to fit the cone tightly, and has 
 a rim around the open end for convenience in handling. 
 It is made of sheet copper, which is first cut into the 
 form of an equilateral cross (a, fig. 114), 
 and then transferred to a die, where it is 
 punched into the required shape (b). It is 
 charged with half a grain of powder, com- 
 posed of equal parts of nitre and fulminate 
 of mercury / the object of the nitre being 
 to retard the combustion of the composition, 
 and give density to the flame. 
 
 The composition is pressed into the cap in a dry 
 state, and covered with a drop of shellac varnish to fix 
 it in its place and protect it from moisture. With the 
 exception of varnishing, all the operations of making 
 percussion-caps are performed by a single machine, at 
 the rate of 50,000 per day. Percussion caps were in- 
 vented in the United States, in 1817. 
 
 355. uiaynard's Primer. This primer is made by 
 indenting a sheet of paper at regular intervals (a a, fig. 
 
 115), filling each indenta- 
 tion with a small charge 
 of percussion powder, and 
 
 Fig. 114. 
 
STAND OF AMMUNITION. 
 
 351 
 
 covering the whole with another sheet of paper, firmly 
 pasted on. The sheet is then cut into strips, each strip 
 containing 60 primers in a single row, and, to protect 
 it from the moisture, it is covered with a thick coat of 
 shellac varnish. 
 
 FIELD AND MOUNTAIN AMMUNITION. 
 
 356. Composition. Ammunition for the field-service 
 is composed of solid shot, shells, spherical-case shot, and 
 canister-shot; in the mountain service, the solid shot 
 are omitted. 
 
 For convenience in loading, and safety in transporta- 
 tion, cannon ammunition should be prepared in a pe- 
 culiar manner, and with great care. 
 
 357. stand of ammunition. A stand of ammunition 
 is composed of the projectile (a, fig. 116), 
 the sabot (Z>), the straps (<?), the cartridge- 
 bag (d), and the cylinder (e) and cap. 
 The preparation of the projectile itself, 
 is described in chapter II. 
 
 Sabot. The sabot is a thick, circular 
 disk of wood, to which the cartridge-bag 
 and projectile are attached. 
 
 For a spherical projectile, the sabot 
 has a spherical cavity (a, fig. 117), and a circular groove 
 
 to which the cartridge-bag is 
 tied; in the canister-sabot, 
 the spherical cavity is omit- 
 ted, and a circular offset (b) 
 is added. 
 The effects of a sabot are: — 1st. To prevent the 
 
 Fig. 116. 
 
 Fig. 117. 
 
352 PYROTECHNY. FIELD AND MOUNTAIN AMMUNITION. 
 
 formation of a lodgment in the bore. 2d. To moderate 
 the action of the powder on the projectile; and, 3d, To 
 prevent the projectile from moving from its place. In 
 consequence of the scattering of the fragments, it is 
 dangerous to use the sabot in firing over the heads of 
 one's own men. 
 
 Straps. The projectile is secured by two tin straps, 
 fastened at the ends with tacks driven into the sabot. 
 The straps cross each other at right angles ; for solid 
 shot, one strap passes through a slit in the other; for 
 hollow projectiles, both straps are fastened to a tin ring 
 which surrounds, the fuze-hole. 
 
 Cartridge-bag. The materials of which cartridge-bags 
 are made are described on page 348. A cartridge-bag 
 for the field service is made of two pieces — a rectangu- 
 lar piece for the sides, and a circular piece for the bot- 
 tom. The rectangular piece should be cut in the direc- 
 tion of the warp, to prevent the bag from stretching in 
 the direction of its diameter; the seams should be 
 sewed with woollen yarn, 12 stitches to the inch, and 
 the edges should be basted down, to prevent the pow- 
 der from sifting through. The charge is determined by 
 measurement. 
 
 Cylinder and cap. The cylinder and cap are' made of 
 stout paper. The cylinder is used to give stiffness to 
 the cartridge at the junction of the sabot and bag ; the 
 cap covers the exposed portion of the bag, and is drawn 
 off before loading, and placed over .the projectile, or 
 thrown away. The cap is made by cutting off a por- 
 tion of the cylinder, and choking one end. The car- 
 tridge-bag is attached to the projectile by tying it 
 around the grooves of the sabot with twine. 
 
CARTRIDGE-BAGS. 353 
 
 358. strapped a mm unit ion. Ammunition thus pre- 
 pared is called fixed ammunition. In the large field 
 howitzers, it is not convenient to unite the cartridge- 
 bag and projectile, on account of the difficulty of pack- 
 ing them in the ammunition chests ; the bag and pro- 
 jectile are therefore carried separately. The projectile 
 is attached to a sabot without grooves ; and, to give a 
 proper form to the cartridge-bag the mouth is closed 
 with a cartridge-Mock, which resembles a sabot; hence 
 the name strapped ammunition. 
 
 359. Packing, &c. As soon as ammunition is finished 
 it should be gauged, to see that it is of the proper cali- 
 bre; it is afterward packed in boxes containing ten 
 rounds each, with scraps of paper, or tow, well rammed 
 into the interstices. 
 
 Ammunition may be distinguished by the color of 
 the cap; for spherical-case shot, it is red; for shells, 
 black ; and for solid-shot and canister, it is the natural 
 color ot the paper. The outside of the packing-box is 
 colored red for spherical-case shot ; black for shells ; 
 olive for shot ; and, for canister, the natural color of the 
 wood ; besides this, it is marked with the number and 
 character of the contents in letters and figures. 
 
 SIEGE AND SEA-COAST AMMUNITION. 
 
 360. Cartridge-bags. On account of the great weight 
 of siege and sea-coast ammunition, the cartridge-bag and 
 projectile are carried separately. 
 
 The cartridge-bags for large charges of powder are 
 made of two pieces of woollen stuff (iig. 118), or of a 
 
 23 
 
354 PYROTECHNY. FIELD AND MOUNTAIN AMMUNITION. 
 
 Fig, 118. 
 
 paper tube, with woollen cloth bottom. 
 The former are preferred for rapid firing. 
 For sea-coast howitzers, the bag should 
 fill the chamber ; if the piece be fired 
 with a reduced charge, a cartridge-block 
 should be inserted into the bag to give 
 it proper size. For mortars the bag is 
 only used to carry the powder, and when the piece is 
 loaded, the powder is poured into the chamber ; bags of 
 any suitable size will answer for this service. For hot- 
 shot cartridges, bags are made double, by putting one 
 bag within another. Care should be taken to see 
 that the bags are free from holes. 
 
 For ricochet firing, or other occasions when very small 
 charges are required, a cartridge-bag of inferior calibre 
 may be used ; or else, after the charge is poured into the 
 bag, place it on another bag filled with hay, pressing 
 it with the hands to reduce the diameter ; after having 
 shaken this bag down, and rolled and flattened the empty 
 parts of the two bags, tie them with woollen yarn, like 
 a bundle of musket-cartridges, placing the knot on top. 
 361. strapping §heii§, &c. In the siege and sea-coast 
 services, solid shot are transported and loaded loosely, 
 but hollow projectiles are strapped 
 to sabots to prevent the fuze from 
 coming in contact with the powder 
 of the charge. The sabots are made 
 from thick plauk (jig. 119), and the 
 straps are fastened as in the field- 
 service. The fuze-hole is placed in 
 one of the angles of the straps, in 
 Fig - 119, such a manner that its axis shall 
 
wads. 355 
 
 make an angle of 45° with that of the sabot. In load- 
 ing, care should be taken to place the fuze-hole up- 
 permost. 
 
 When there are no ears on the projectile, a handle of 
 rope-yarn is attached to two loops soldered to one of 
 the straps, or it is passed through two holes bored in 
 the bottom of the sabot. 
 
 362. Filling shells. Shells are filled with cannon- 
 powder alone, or with cannon-powder and some kind 
 of incendiary composition. Before filling, the shell 
 should be inspected, to see that it is dry, clean, and free 
 from defects.* 
 
 The service bursting-charges of powder for the larger 
 shells are : — 
 
 15 -INCH. 13-INCH. 10-INCH. 8-INCH. 
 
 Mortar-shell, 7 lbs. 5 lbs. 2-J- lbs. 
 
 Columbiad-shell, . 11 lbs. " 3 lbs. 1-L lbs. 
 
 363. Wads. Junk wads having been found detri- 
 mental in ordinary firing, are only used for proving 
 cannon. 
 
 For firing hot-shot, a hay wad, soaked in water, is 
 interposed between the powder and shot. The wad is 
 made by twisting the hay into a rope, winding the rope 
 into a coil, which is driven into wooden moulds of the 
 proper size. To preserve the size and form of the wad 
 it is afterward wrapped tightly with rope-yarn. 
 
 Grommets. Grommets, or ring wads, are useful in 
 increasing the accuracy of fire, and keeping the projec- 
 tile in its place when the piece is moved or depressed. 
 
 * To find the quantity of powder which a shell will contain, multiply the cube of 
 the interior diameter of the shell in inches by 0.01744, the result is the weight 
 of powder in pounds. 
 
356 PYKOTECHNY. MILITARY EIREWOKKS. 
 
 It is made by bending a strand of rope into the form 
 of a circle, and wrapping it with rope-yarn. The size 
 of the ring is the full diameter of the bore, that it may 
 fit tightly. This wad is attached to the front of the 
 projectile with twine; or, it may be inserted after the 
 projectile, like ordinary wads. 
 
 MILITAEY FIEEWOEKS. 
 
 364. Comprise what. Military fireworks comprise 
 preparations for the service of cannon ammunition, and 
 for signal, light, incendiary, and defensive and offensive 
 purposes. 
 
 365. Compositions. The term composition is applied 
 to all mechanical mixtures which, by combustion, pro- 
 duce the effects sought to be attained in pyrotechny. If 
 these compositions be examined, it will be found that 
 many of them are derived from gunpowder, by an ad- 
 mixture of sulphur and nitre, in proportions to suit the 
 required end; a German writer has even proposed to 
 extend this method to the formation of all the principal 
 compositions, but the simplicity of the plan has never 
 been fully realized in practice. 
 
 Preparation. Compositions are prepared in a dry or 
 liquid form ; in either case it is necessary that the in- 
 gredients should be pure, and thoroughly mixed. 
 
 For dry compositions, the ingredients are pulverized 
 separately, on a m^^m^-table, with a wooden muller; 
 they are then weighed, and mixed with the hands, and 
 afterward passed three times through a wire sieve of a 
 certain fineness. When a highly oxydizing substance, 
 as the chlorate of potassa, is present, great care must be 
 
COMPOSITIONS. 357 
 
 observed in mixing, to avoid friction or blows, which 
 might lead to an explosion. When coarse charcoal, or 
 metals in grains are used, they should be added after 
 the other ingredients have been mixed and sifted. 
 
 For the liquid form. When it becomes necessary to 
 use fire to melt the ingredients, the greatest precaution 
 is necessary to prevent accidents, particularly when 
 gunpowder enters. The dry parts of the composition 
 may be, generally, mixed together first, and put by 
 degrees into the kettle, when the other ingredients 
 are fluid, stirring well all the time. When the dry 
 ingredients are very inflammable, the kettle must 
 not only be taken from the fire, but the bottom must 
 be dipped in water, to prevent the possibility of acci- 
 dents. 
 
 How disposed. To give a portable form to composi- 
 tions, they are enclosed in cases, cast in moulds, or at- 
 tached to cotton yarn, rope, &c. 
 
 • Cases. Cases are generally paper tubes, made by 
 covering one side of a sheet 
 of paper with paste, or gum- 
 arabic, wrapping it around a 
 former, and rolling it under a 
 flat surface until all the layers 
 adhere to each other (fvg. 120). The quality of the 
 paper, and the thickness of the sides of the case, should 
 depend upon the pressure of the gases evolved in the 
 burning. 
 
 Filling. To fill a case, it is first cut to the proper 
 length, and placed in a mould ; the composition is then 
 poured in, a ladleful at a time, and each ladleful is 
 packed by striking a certain number of blows on a drift 
 
 Fig. 120. 
 
358 -PYROTECITNT. MILITARY FIREWORKS. 
 
 with a mallet of a given weight. The height of each 
 ladleful of composition should be about equal to a sin- 
 gle diameter of the bore of the case. 
 
 Drifts, &c. Small drifts, receiving heavy blows, 
 should be made of steel, and 
 tipped with bronze (fig. 121) ; 
 
 large drifts may be made of Fig. 121. 
 
 wood or bronze, depending on the force of the blow. 
 In driving highly inflammable compositions, as that of 
 the rocket, care should be taken to settle the drift, so 
 as to exclude the air before striking with the mallet, as 
 the heat generated by the sudden condensation of air 
 might be sufficient to ignite the composition. 
 
 Preliminary tests of all new materials should be made 
 by burning one or more specimens of the composition, 
 and the proportions of the ingredients corrected, if 
 necessary. 
 
 Vent, &c. The length of the flame from a given com- 
 position depends on the size of the vent and the extent 
 of the burning surface. The vent is made small by 
 choking the end of the case with stout twine ; and the 
 burning surface is increased by driving the composition 
 around a spindle, which, on being withdrawn, leaves a 
 conical-shaped cavity. A vent may be also formed by 
 driving in moist plaster of Paris or clay, and boring a 
 hole in it with a gimlet. If the end of the case is to be 
 closed up entirely the boring is omitted. 
 
 366. For ammunition. The preparations for the ser- 
 vice of ammunition are slow-match, quick-match, port-fires, 
 friction-tubes, and fuzes. 
 
 367. Slow-match. Slow-match is used to preserve 
 fire. It may be made of hemp or cotton rope ; if made 
 
FRICTION-TUBE. 359 
 
 of hemp, the rope is saturated with acetate of lead, or 
 the lye of wood-ashes; if made of cotton, it is only 
 necessary that the strands be well twisted. Slow-match 
 "burns from four to five inches in an hour. 
 
 368. Quick-match. Quick-match is made of cotton 
 yarn (candle-wick) saturated with a composition of 
 mealed powder and gummed spirits ; after saturation, 
 the yarn is wound on a reel, sprinkled (dredged) with 
 mealed powder, and left to dry. 
 
 It is used to communicate fire, and "burns at the rate 
 of one yard in thirteen seconds. The rate of burning 
 may be much increased by enclosing it in a thin paper 
 tube called a leader. ' 
 
 369. Port-fires. A port-fire is a paper case containing 
 a composition, the flame of which is capable of quickly 
 igniting primers, quick-match, &c. 
 
 The composition consists of — 
 
 NITRE. 
 
 SULPHUR. 
 
 MEALED POWDER. 
 
 6 
 
 3 
 
 1 
 
 A port-fire is about 22 inches long, and burns with 
 an intense flame for ten minutes. 
 
 370. Friction-tube. The friction-tube is at present 
 the principal preparation for firing cannon ; its advan- 
 tages are portability and certainty of fire. It also affords 
 the means of firing a piece situated at a distance, and 
 does not attract the notice of the enemy's marksmen at 
 night. 
 
 It is composed of two brass tubes soldered at right 
 
360 
 
 PYROTECH1SV. MILITARY FIREWORKS. 
 
 angles (rig. 122). The upper, or short tube 
 contains a charge of friction powder, and 
 the roughed extremity of a wire loop (a) 
 (the extremity is shown by fig. Z>) ; the long 
 tube is filled with rifle powder, and is in- 
 serted in the vent of the piece. When the 
 extremity of the loop is violently pulled by 
 means of a lanyard, through its hole in the 
 long tube, sufficient heat is generated to ig- 
 nite the friction powder which surrounds it, and this 
 communicates with the grain-powder in the long tube. 
 The charge of grained powder has sufficient force to 
 pass through the longest vent, and penetrate several 
 thicknesses of cartridge-cloth. The composition of fric- 
 tion powder is: — 
 
 Fig. 122. 
 
 CHLORATE OF POTASS A. 
 
 SULPHURET OF ANTIMONY. 
 
 2 
 
 1 
 
 formed into a paste with gum- water. 
 
 371. Fuzes. Fuzes are the means used to ignite the 
 bursting-charge of a hollow projectile at any desired 
 moment of its flight ; they may be classified according 
 to their mode of operation, as percussion, concussion, 
 and time-fuzes. 
 
 Time-fuze. This fuze is composed of a case of paper, 
 wood, or metal, enclosing a column of burning compo- 
 sition, which is set on fire by the discharge of the piece, 
 and which, after burning a certain time, communicates 
 with the bursting-charge. 
 
 Its successful operation depends on the certainty of 
 
FUZES. 361 
 
 ignition, the uniformity of burning, and the facility 
 with which its flame communicates with the bursting- 
 charge. 
 
 Composition. The ingredients of all time-fuze compo- 
 sitions are the same as for gunpowder, but the propor- 
 tions are varied to suit the required rate of burning- 
 Pure mealed powder gives the quickest composition, 
 and the others are derived from it by the addition of 
 nitre and sulphur in certain quantities. 
 
 The rate of burning of a column of fuze composition 
 depends on the purity and thorough incorporation of the 
 materials, and on its density. These qualities are best 
 secured by procuring the materials from the powder, 
 mills ready mixed, and driving them with a press of 
 peculiar construction. 
 
 Three kinds of time-fuzes are employed in the United 
 States service, viz.: the mortar-fuze, the Bormann-ftize, 
 and the sea-coast fuze. 
 
 Mortar-fuze. The case of the mortar-fuze is made of 
 beech-wood, turned in a lathe to a conical shape, and 
 bored out nearly to the bottom to receive the composi- 
 tion (fig. 123). The composition is driven with 
 fifteen blows of the mallet. The bore is en- 
 larged at the top to receive a priming of mealed 
 powder moistened with alcohol. To protect the 
 priming from injury by moisture, the top of the 
 fuze is covered with a cap of water-proof paper, 
 on which is marked the rate of burning of the 
 composition. The exterior is divided into inches Fig. 123. 
 and tenths, to guide the gunner in regulating the time 
 of burning. This operation is generally performed be- 
 fore the fuze is driven into the fuze-hole of the shell, by 
 
362 
 
 PYROTECHNY. MILITARY FIREWORKS. 
 
 
 cutting it off with a saw, or boring into the composition 
 with a gimlet. 
 
 If the fuze be driven, the column of composition may 
 be shortened by taking a portion from the top with the 
 fuze-auger. 
 
 372. Bormann-fnze. This fuze is the invention of 
 an officer of the Belgian service. The case is made of 
 an alloy of tin and lead, cast in iron moulds. Its shape 
 is that of a thick, circular disk ; and a screw thread is 
 cut upon its edge, by which it is fast- 
 ened into the fuze-hole of the project- 
 ile. (See figure 124.) The upper sur- 
 face is marked with two recesses (a a), 
 and a graduated arc. The former are 
 made to receive the prongs of a screw- 
 driver ; and the latter overlies a circu- 
 lar groove, filled with mealed powder, 
 tightly pressed in and covered with 
 metal cap. The only outlet to the groove containing 
 the mealed powder is under the zero of the graduation ; 
 this outlet, or channel (<?), is filled with rifle powder, 
 and leads down to a circular recess (7>), which is filled 
 with musket powder, and covered with a perforated 
 disk of tin. To enable this fuze to resist the shock of 
 discharge, and at the same time to increase the effect of 
 a small bursting-charge, the lower portion of the fuze- 
 hole is closed with a perforated disk (e). 
 
 Before the projectile is inserted into the piece, a cut 
 is made across the graduated portion, laying bare a 
 small proportion of the mealed powder, which, 1 being ig- 
 nited by the flame of the charge, burns in both direc- 
 tions until the outlet is reached and the grain powder 
 
 Fig. 124. 
 
SEA-COAST FUZE. 363 
 
 ignited. The graduations are seconds and quarter sec- 
 onds, and the time of burning of the fuze depends on 
 the length of the column of mealed powder included 
 between the incision and outlet. If the metal covering 
 be not cut, the projectile may be fired as a solid shot 
 The Bormann-fuze is used for the field and siege ser- 
 vices, and is found to be accurate and reliable, especially 
 for spherical-case shot.* 
 
 373. Sea-coa§t fuzc.-f- The sea-coast fuze is princi- 
 pally distinguished from the mortar-fuze 
 by having a metal cap, constructed to pre- 
 vent the burning composition from being 
 extinguished when the projectile strikes 
 against water. 
 
 It is composed of a brass plug (a y fig. 
 125), which is firmly driven into the fuze- 
 hole of the projectile ; a paper-fuze (7>), in- 
 serted into the plug, with the fingers, im- Bg. 125. 
 mediately before loading the piece ; and a water-cap (<?), 
 screwed into the plug after the paper-fuze has been 
 inserted. 
 
 The water-cap is perforated with a crooked channel, 
 which is filled with mealed powder ; the mealed powder 
 communicates fire to the paper-fuze, and the angles of 
 the channel break the force of the water. 
 
 The top of the cap has a recess which is filled with a 
 priming of mealed powder, and is covered with a disk 
 
 * The time of burning of the Bormann-fuze, not being long enough for the gen- 
 eral service of rifle projectiles, the paper time-fuze (b. fig. 125) is used instead of it 
 for all of those projectiles which require the time-fuze. It is inserted into a zinc 
 plug, which is screwed into the fuze-hole of the projectile. 
 
 f This valuable fuze was invented by the late Mr. Cyrus Alger, of Boston, Mas- 
 sachusetts, in 1842. 
 
364 
 
 PYROTECHNT. MILITARY FIREWORKS. 
 
 of sheet lead to prevent accidental ignition ; before load- 
 ing, this disk is removed. The time of burning is reg- 
 ulated by the proportion of the ingredients of the 
 composition ; and this is indicated by the number of 
 seconds marked on the paper case. In firing over land, 
 the water-cap is omitted, and the brass plug may, for 
 the sake of economy, be replaced by a wooden one. 
 One advantage of this form of fuze is, that the bursting- 
 charge may be put in, or taken out, after the fuze-plug 
 has been driven. 
 
 374. Concii§§ion-fuze. A concussion-fuze is made 
 to operate by the shock of the discharge, or by the 
 shock experienced in striking the object, and is applica- 
 ble to spherical projectiles. One of the simplest, as well 
 as one of the most effective, concussion-fuzes is that in- 
 vented by Captain Splingard, of the Belgian service; 
 and for the purpose of illustrating the principle of this 
 class of fuzes, it may be proper to give an outline of its 
 construction. 
 
 It is composed of two principal parts, the wooden 
 plug, and the paper-fuze. The chief pecu- 
 liarity lies in the arrangement of the paper- 
 fuze. The case (#, Hg. 126), is made of 
 paper, rendered incombustible by a solution 
 of sulphate of ammonia and alum, and filled 
 with fuze composition (7>) of variable quick- 
 ness of burning. A long cavity is formed in 
 the lower part of the composition, by driving 
 it around a spindle, as in a rocket ; this cav- 
 ity is filled with moist plaster of Paris, and a rig. 12 6. 
 long needle is inserted in it, nearly to the bottom of the 
 plaster, forming a tube (<?) enclosed in and supported 
 
PERCUSSION-FUZE. 365 
 
 by the composition. The composition is ignited in the 
 usual way, at the top, and, as it burns away, leaves a 
 portion of the plaster tube unsupported ; when the shell 
 strikes its object, the shock breaks off the unsupported 
 part of the tube, and the flame of the composition im- 
 mediately communicates with the bursting-charge ; if 
 the tube do not break, the composition burns up, and the 
 bursting-charge is ignited, as in an ordinary time-faze. 
 The upper portion of the composition burns away quick- 
 ly, in order to leave the tube unsupported soon after 
 the projectile leaves it piece. 
 
 375. Percu§sioii-fuse. A percussion-fuse explodes by 
 the striking of some particular point of a projectile 
 against an object, as in the case of rifle-cannon projectiles. 
 One of the best and simplest forms of this kind of 
 fuze is the ordinary percussion-cap placed on a cone 
 affixed to the point of the projectile. The piece to 
 which the cone is attached may be fixed or movable ; 
 in either case, the apparatus should be covered with a 
 safety-cap to prevent the percussion-cap from taking 
 fire by the discharge of the piece. 
 
 Fig. 127 represents a fuze of the per- 
 cussion kind, in which b is a movable 
 cone-piece, bearing a musket-cap (<?) ; and 
 a is the safety-cap which covers the fuze- 
 hole. When the projectile is set in mo- 
 tion, the cone-piece, or " plunger," by its 
 inertia, presses against the shoulders of 
 Fig. m. ^ e f uze _h l e .-* w hen its motion is ar- 
 
 * The plunger is kept in its place by a paper washer, the diameter of which 
 is a little larger than that of the fuze-hole ; before loading the piece, the plunger 
 should be examined, to see that it is not clogged by the powder contained in the 
 shell. 
 
366 PYR0TECHTSY. FIREWORKS FOR SIGNALS. 
 
 rested, the inertia of the cone-piece causes the percus- 
 sion-cap to impinge against the safety-cap, which pro- 
 duces explosion. The explosion of the projectile may 
 be made to take place at any desired time, after the ex- 
 plosion of the cap, by interposing grain, or mealed pow- 
 der, between the cap and bursting-charge. 
 
 FIREWORKS FOR SIGNALS. 
 
 The preparations employed for signals are rockets and 
 blue-lights. 
 
 376. Signal rockets. The principal parts of a signal 
 rocket are the case (a), the composition (£), the pot (c), 
 the decorations (e) y and the stick (/). 
 
 Fig. 128. 
 
 Case. The case is made by rolling stout paper covered 
 on one side with paste, around a former, and at the 
 same time applying a pressure until all the layers adhere 
 to each other. The vent is formed by choking one end 
 of the case, and wrapping it with twine. When the 
 case is trimmed and dried, it is ready for driving the 
 composition. 
 
 Composition. A variety of compositions are employed 
 for signal rockets ; the best can only be determined by 
 trial, as it varies with the condition of the ingredients. 
 The following proportions are used at the West Point 
 laboratory : 
 
SIGNAL SOCKETS. 
 
 367 
 
 NITRE. 
 
 SULPHUR. 
 
 CHARCOAL. 
 
 12 
 
 2 
 
 3 
 
 to increase the length and brilliancy of the trail, add 
 steel, or cast-iron filings. 
 
 Driving. The case is placed in a copper mould which 
 has a conical spindle attached to the centre of its base, 
 to form the bore ; the composition is driven with twenty- 
 one blows of the mallet. The first and second drifts are 
 made hollow to fit over the spindle, and the third is 
 solid. The top of the case is closed by moist plaster of 
 Paris, which is one diameter thick, and perforated with 
 a hole for the passage of the flame from the burning 
 composition to the pot. The rocket is primed by insert- 
 ing a strand of quick-match into the bore, after which 
 it is coiled up, and covered with a paper cap, until re- 
 quired for use. 
 
 Pot. The pot is formed of a paper cylinder slipped 
 over, and pasted to the top of the case ; it is surmounted 
 with a paper cone, filled with tow. The object of the 
 pot is to contain the decorations which are scattered 
 through the air by the explosion which takes place 
 when the rocket reaches the summit of its trajectory ; 
 the explosion is produced by a small charge of mealed 
 powder. 
 
 Decorations. The decorations of rockets are stars, 
 serpents, marrons, gold rain, rain of fire, &c. 
 
 Stars. Stars are formed by driving the composition, 
 moistened with alcohol and gum-arabic in solution, in 
 
368 
 
 PYEOTECHNY. FIEE-WOEKS FOE SIGNALS. 
 
 port-fire moulds. It is then cut into lengths about f in., 
 and dredged with mealed powder. 
 
 White. 
 
 NITRE. 
 
 SULPHUR. 
 
 MEALED POWDER. 
 
 7 
 
 3 
 
 2 
 
 Red. 
 
 CHLOKATE OF 
 POTASSA. 
 
 SULPHUR. 
 
 LAMPBLACK. 
 
 NITRATE OF 
 STRONTIA. 
 
 7 
 
 4 
 
 1 
 
 12 
 
 Blue. 
 
 CHLORATE OF POTASSA. 
 
 SULPHUR. 
 
 1 
 
 AMMONIACAL SULPHATE 
 OF COPPER. 
 
 3 
 
 1 
 
 1 
 
 Yellow. 
 
 1 
 
 CHLORATE OF 
 POTASSA. 
 
 SULPHUR. 
 
 SULPHATE OF 
 STRONTIA. 
 
 BICARBONATE 
 OF SODA. 
 
 4 
 
 2 
 
 1 
 
 1 
 
 Serpents. The case of a serpent is similar to that 
 of a rocket, but the interior diameter is only 0.4 inch. 
 The composition is driven in, and the top is closed with 
 moist plaster of Paris. It is primed by inserting a small 
 
BLUE-LIGHT. 
 
 369 
 
 piece of quick-match through the vent ; it may be made 
 to explode by driving mealed powder over the composi- 
 tion. The composition is — 
 
 NITRE. 
 
 SULPHUR. 
 
 MEALED POWDER. 
 
 CHARCOAL. 
 
 3 
 
 3 
 
 16 
 
 1 
 2 
 
 Marrons. Marrons are small paper shells, or cubes, 
 filled with grained powder, and primed with a short 
 piece of quick-match, which is inserted in a hole punc- 
 tured in one of the corners. To increase the resistance 
 of the shell, it is wrapped with twine, and dipped in 
 hit composition. 
 
 Stick. The stick is a tapering piece of pine, about 
 nine times the length of the case, and is tied to the side 
 of the case to guide the rocket in its flight. The posi- 
 tion of the centre of gravity depends on the diameter of 
 the case ; for a 2-in. rocket it should be 2^ in. in rear of 
 the vent; and it is verified by balancing on a knife- 
 edge. The prescribed dimensions of the stick should 
 be observed, for, if the stick be too heavy, the rocket 
 will not rise to a proper height ; if it be too light, it 
 will not rise vertically. 
 
 37 7. Bine-light, A very brilliant bluish light may be 
 made of the following ingredients, viz. : 
 
 NITRE. 
 
 SULPHUR. 
 
 REALGAR. 
 
 1 
 
 MEALED POWDER. 
 
 14 
 
 3.7 
 
 1 
 
 1 
 
 The brilliancy depends on the purity and thorough 
 
 24 
 
370 
 
 PYROTECHNY. INCENDIARY FIREWORKS. 
 
 incorporation of the ingredients. The composition may 
 be driven in a paper case, and afterward cut off to suit 
 the required time of burning. Both ends of the case are 
 closed with paper caps, and primed with quick-match, 
 in order that one or both ends may be lighted at pleas- 
 ure. A light in which the composition is 1.5 inches 
 diameter can be easily distinguished at the distance of 
 15 miles. 
 
 INCENDIARY FIREWORKS. 
 
 Incendiary preparations are fire-stone, carcasses, incen- 
 diary-match, and hot shot 
 
 378. Firestone. Fire-stone is a composition that 
 burns slowly, but intensely; it is placed in a shell, 
 along with the bursting-charge, for the purpose of set- 
 ting fire to ships, buildings, &c. 
 
 Composition. It is composed of — 
 
 NITRE. 
 
 SULPHUR. 
 
 ANTIMONY. 
 
 I 
 ROSIN. 
 
 10 
 
 4 
 
 1 
 
 3 
 
 Preparation. In a furnace of the second kind, or in. 
 a kettle in the open air, melt together one part of mut- 
 ton tallow and one part of turpentine / the composition, 
 having been properly pulverized and mixed, is added to 
 the melted tallow and turpentine, in small quantities. 
 Each portion of the composition should be well stirred 
 with long wooden spatulas to prevent it from taking 
 fire, and each portion should be melted before another 
 is added. 
 
CARCASS. 371 
 
 How used. When fire-stone is to be used in shells, 
 it is cast into cylindrical moulds, made by rolling 
 rocket-paper around a former, and securing it with 
 glue. A small hole is formed in the composition by 
 placing a paper tube in the centre of each 
 mould (a, Hg. 129). When the melted 
 composition has become hard, this hole is 
 
 Fig. 129. filled with a priming of fuze composition, 
 driven as in the case of a fuze. The object of this 
 priming is to insure the ignition of the fire-stone by the 
 flame of the bursting charge. 
 
 There are two sizes of moulds, the largest for shells 
 above the 8-in., and the other for the 8-in. and all 
 below it. 
 
 379. Carcass. A carcass is a hollow cast-iron projec- 
 tile filled with burning composition, the flame of which 
 issues through four fuze-holes, to set fire to combustible 
 objects. 
 
 Composition. The composition is the same as for port- 
 fires, mixed with a small quantity of finely-chopped tow, 
 and as much white turpentine and spirits of turpentine 
 as will give it a compressible consistency. 
 
 Preparation. The composition is compactly pressed 
 into the carcass with a drift, so as to fill it entirely. 
 Sticks of wood 0.5 in. diameter are then inserted into 
 each fuze-hole, with the points touching at the centre, 
 so that when withdrawn corresponding holes shall re- 
 main in the composition. In each hole, thus formed, 
 three strands of quick-match are inserted, and held in 
 place by dry port-fire composition, which is pressed 
 around them. About three inches of the quick-match 
 hangs out when the carcass is inserted in the piece ; pre- 
 
372 PYROTECHNY. FIREWORKS EOR LIGHT. 
 
 viously to that, it is coiled up in the fuze-hole, and closed 
 with a patch of cloth dipped in melted kit. 
 
 A common shell may be loaded as a carcass by placing 
 the bursting-charge on the bottom of the cavity, and 
 covering it with carcass composition, driven in until the 
 shell is nearly full, and then inserting four or five strands 
 of quick-match, secured by driving more composition. 
 This projectile, after burning as a carcass, explodes as a 
 shell. 
 
 380. incendiary match. Incendiary match is made 
 by boiling slow-match in a saturated solution of nitre ; 
 drying it ; cutting it into pieces, and plunging it into 
 melted fire-stone. It is principally used in loaded shells. 
 
 381. Hotshot. For the purpose of setting fire to 
 wooden vessels, buildings, &c, solid shot are heated in 
 a furnace, before firing, to a red heat.* The time required 
 to heat a 42-pdr. shot to a red heat is about half an 
 hour. The precautions to be observed in loading hot 
 shot are, that the cartridge be perfectly tight, so that the 
 powder shall not scatter along the bore, and that a wad 
 of pure clay, or hay, soaked in water, be interposed be- 
 tween the cartridge and the shot. When properly 
 loaded, the shot may be allowed to cool without igniting 
 the charge. 
 
 FIREWORKS FOR LIGHT. 
 
 The preparations for producing light are fire-balls, 
 light-balls, tarred links, pitched fascines, and torches. 
 
 * In the British sea-coast service shells are used for incendiary purposes by fill- 
 ing them with molten iron drawn from a small cupola furnace. If the shell be 
 broken on striking, the hot iron is scattered about ; if it be not broken, the heat pene- 
 trates through the shell with sufficient intensity to set wood on fire. 
 
FIRE-BALL. 
 
 373 
 
 382. Fire-ball. A fire-ball is an oval-shaped canvas 
 sack, filled with combustible composition 
 (fig. 130). It is intended to be thrown 
 from a mortar to light np the works of 
 an enemy, and is loaded with a shell to 
 prevent it from being approached and ex- 
 tinguished. 
 
 Sack. The sack is made of sail-cloth, 
 cut into three oval pieces or gores, and 
 sewed together at their edges. Several thicknesses of 
 cloth may be used, if necessary. One end of the sack is 
 left open, and, after being sewed, it is turned to bring 
 the seam on the inside. 
 
 Composition. The composition for a fire-ball consists 
 of— 
 
 Fig. 130. 
 
 NITRE. 
 
 SULPHUR. 
 
 ANTIMONY. 
 
 * 
 
 8 
 
 2 
 
 1 
 
 After being pulverized, mixed, and sifted, the compo- 
 sition is moistened with one-thirtieth of its weight of 
 water, and again passed through a coarse sieve. The 
 ball is filled by pouring a layer of composition into the 
 sack, and placing the shell (fuze down) upon it ; after 
 this, the composition is well rammed around and above 
 the shell, and the sack is closed at the top. 
 
 Finishing. The bottom of the sack is protected from 
 the force of the charge by an iron cup (a), called a culot, 
 and the whole is covered and strengthened with a net- 
 work of spun-yarn, or wire, and then overlaid with a 
 composition of pitch, rosin, <fcc. * 
 
374 PYEOTECHNY. FIEEWOEKS FOE LIGHT. 
 
 A fire-ball is primed by driving into the top of the 
 composition a greased wooden pin about three inches 
 deep, and filling the hole thus formed with fuze com- 
 position, driven as in a fuze ; space is left at the top of 
 each hole for two strands of quick-match, which are 
 fastened by driving the composition upon them. The 
 fuze-hole is covered with a patch saturated with kit 
 composition, which is a mixture of rosin, beeswax, pitch, 
 and tallow. ^ 
 
 383. Light-bail. Light-balls are made in the same 
 manner as fire-balls, except that, being used to light up 
 our own works, the shell is omitted. 
 
 384. Tarred links. Tarred links are used for lighting 
 up a rampart, defile, <fcc, or for incendiary purposes. 
 They consist of coils of soft rope, placed on top of each 
 other, and loosely tied together ; the exterior diameter 
 of the coil is 6 inches, and the interior 3 inches. They 
 are immersed for about ten minutes in a composition of 
 20 parts oi pitch, and one of tallow, and then shaped under 
 water ; when dry, they are plunged in a composition of 
 equal parts of pitch and rosin, and rolled in tow or saw- 
 dust. To prevent the composition from sticking to the 
 hands, they should be previously covered with linseed 
 oil. 
 
 How used. Two links are put into a rampart grate, 
 separated by shavings. They burn one hour in calm 
 weather, and half an hour in a high wind, and are not 
 extinguished by rain. To light up a defile, the links 
 are placed about 250 feet apart; to light up a march, 
 the men who carry the grates should be placed to the 
 leeward of the column, and about 300 feet apart. 
 
 385. Pitched fascines. Fagots of vine-twigs, or other 
 
TOKCHES. 
 
 375 
 
 very combustible wood, about 20 in. long and 4 in. diam- 
 eter, tied in three places with iron wire, may be treated 
 in the same manner, and used for the same purposes as 
 links. The incendiary properties of pitched fascines 
 may be increased by dipping the ends in melted rock- 
 fire; when used for this purpose, they are placed in 
 piles intermingled with shavings, quick-match, bits of 
 port-fires, &c, in order that the whole may take fire at 
 once. 
 
 386. Torches. A torch is a ball of rope impregnated 
 with an inflammable composition, and is fastened to the 
 end of a stick, which is carried in the hand. 
 
 Preparation. Old rope, or slow-match, well beaten 
 and untwisted, is boiled in a solution of equal parts of 
 water and nitre; after it is dry, tie three or four pieces 
 (each four feet long) around the end of a pine stick, 
 about two inches diameter, and four feet long ; cover 
 the whole with a mixture of equal parts of sulphur and 
 mealed powder, moistened with brandy, and fill the 
 intervals between the cords with a paste of three parts 
 of sulphur and one of quicklime. When it is dry, 
 cover the whole with the following composition : 
 
 
 PITCH. 
 
 VENICE TURPENTINE. 
 
 TURPENTINE. 
 
 3 
 
 3 
 
 1 
 2 
 
 
 How used. Torches are lighted at the top, which is 
 cracked with a mallet; they burn from one and a quar- 
 ter to two hours. In lighting the march of a column, 
 the men who carry torches should be about 100 feet 
 apart. 
 
376 PYROTECHNY. — OFFENSIVE. ETC., FIREWORKS 
 
 OFFENSIVE AND DEFENSIVE FIEEWOKKS. 
 
 The principal preparations of this class, employed in 
 modern warfare, are bags of powder and light-barrels. 
 
 387. Bag§ of powder. Bags or cases of powder may 
 be used to blow down gates, stockades, or form breaches 
 in thin walls. The petard was formerly employed for 
 these purposes, but it 'is now generally thrown aside. 
 
 From trials made in England, it has been shown that 
 a sand-bag (covered with tar, and sanded to prevent it 
 from sticking) containing 50 lbs. of powder, has, suffi- 
 cient force to blow down a gate formed of 4-inch oak 
 scantling, and supported by posts 10 inches in diameter, 
 and 8 feet apart; and a bag containing 60 lbs. of pow- 
 der, and weighted with two or three bags of earth, has 
 sufficient force to make a large hole in a 14-inch brick 
 wall. The effect of the explosion may be much in- 
 creased by making three sides of the bag with leather, 
 and the fourth of canvas, which should rest against 
 the object. A suitable means of exploding bags of 
 powder is a time-fuze, or the ordinary safety -fuze for 
 blasting rocks. 
 
 388. JLight-harrei. A light-barrel is a common pow- 
 der-barrel pierced with numerous holes, and filled with 
 shavings that have been soaked in a composition of 
 pitch and rosin; it serves to light up a breach, or the 
 bottom of a ditch. 
 
 OENAMENTAL FIREWORKS. 
 389. Object, &c. Ornamental fireworks are employed 
 
GERBE. 377 
 
 to celebrate great events, as victories, treaties of peace, 
 funerals, <fcc. They are divided into fixed pieces, mov- 
 able pieces, decorative pieces, and preparations for com- 
 municating fire from one part of a piece to another. 
 The different effects are produced by modifying the pro- 
 portions of the ingredients of the burning composition, 
 so as to quicken or retard combustion, or by introducing 
 substances that give color and brilliancy to the flame. 
 The fixed pieces are lances, petards, gerbes, flames, &c. 
 
 390. i^ance. Lances are small paper tubes from 0.2 
 to 0.4 in. diameter, filled with a composition which emits 
 a brilliant light in burning 
 (a, fig. 131). Instead of a sin- 
 gle composition, each lance 
 may contain two or more Fig. isl 
 compositions, which, in turn, emit different-colored 
 flames. The case should be as thin as possible, in order 
 that the color of the flame of the composition may not 
 be affected by that of the paper. Lances are generally 
 employed to form figures; this is done by dipping one 
 end in glue, and sticking them in holes arranged after 
 a certain design, in a piece of wood- work. 
 
 391. Petard. Petards are small paper cartridges filled 
 with powder. One end is entirely choked, and the 
 other is left partially open for the passage of a strand 
 of quick-match, destined to set fire to the powder. 
 
 A petard is usually placed at the fixed end of a lance, 
 that the flame may terminate with an explosion (b, fig. 
 131) ; they are also used to imitate the fire of mus- 
 ketry. 
 
 392. Oerbe. Gerbes are strong paper tubes or cases, 
 filled with a burning composition. The ends are tamped 
 
378 
 
 PYKOTECHNY. MOVABLE PIECES. 
 
 with moist plaster of Paris or clay; through one, a hole 
 is bored, extending a short distance into the composi- 
 tion, that it may emit a long sheaf or gerbe of brilliant 
 sparks. 
 
 The diameter of the case is about one inch, and the 
 length depends upon the required time of burning. 
 The number of blows to each ladleful of composition 
 is ten. 
 
 Gerbes are secured to the frame of the piece with wire 
 or strong twine, and pointed in the direction that the 
 flame is to take. 
 
 Composition. 
 
 MEALED POWDER. 
 
 NITRE. 
 
 SULPHUR. 
 
 CAST-IRON FILINGS 
 MIXED WITH SULPHUR. 
 
 32 
 
 16 
 
 10 
 
 26.4 
 
 393. Flame. Flames consist of lance or star compo- 
 sition, driven into paper cases or earthen vases. The 
 diameter of the burning surface should be large, to give 
 intensity to the flame. Lance composition is driven 
 dry, and with slight pressure. Star composition should 
 be moistened, and driven with greater pressure than the 
 preceding. 
 
 MOVABLE PIECES. 
 
 The movable pieces are shy -rockets, tourbillions,saxons, 
 jets, Roman candles, paper shells, &c. 
 
 394. Sky-rocket. Sky-rockets are the same as the 
 signal-rockets before described, except that the com- 
 
JETS. 
 
 379 
 
 position is arranged to give out a more brilliant train 
 of fire. 
 
 Composition. 
 
 MEALED POWDER. 
 
 NITRE. 
 
 SULPHUR. 
 
 CAST-IRON FILINGS. 
 
 122 
 
 80 
 
 40 
 
 40 
 
 395. Tourbiiiion. The tourbillion is a case filled with 
 sky-rocket composition, and which moves with an up- 
 ward spiral motion. The spiral motion is produced by 
 six holes — two lateral holes (one on each side), for the 
 rotary motion, and four on the under side, for the up- 
 ward motion. It is steadied by two wings formed by 
 attaching a piece of a hoop to the middle of the case, 
 and at right angles to its length. 
 
 To give it a proper initial direction, a hole is made 
 through the centre of the case to fit on a vertical spin- 
 dle, which is fastened to an upright post. 
 
 396. Saxon. The saxon is the same as the tour- 
 billion, except that it is only pierced with the central 
 and two lateral holes, and has no wings. The central 
 hole is placed on a horizontal spindle, and the piece has 
 the appearance of a revolving sun. 
 
 397. Jet§. Jets are rocket-cases filled with a burning 
 composition ; they are attached to the circumference of 
 a wheel, or the end of a movable arm, to set it in 
 motion. They also produce the effect of gerbes ; and to 
 increase the circle of fire, they are inclined to the radius 
 at an angle of 20° or 30°. 
 
380 PYROTECHNY. MOVABLE PIECES. 
 
 Com/position. 
 
 MEALED POWDER. 
 
 NITRE. 
 
 SULPHUR. 
 
 CAST-IRON FILINGS. 
 
 50 
 
 36.5 
 
 15 
 
 24.6 
 
 398. Roman candle*. A Roman candle is a strong 
 paper tube containing stars, which are successively 
 thrown out by a small charge of powder placed under 
 each star. A slow-burning composition is placed over 
 each star to prevent all of them from taking fire at 
 once. 
 
 Slow Composition. 
 
 MEALED POWDER. 
 
 CHARCOAL. 
 
 2 
 
 1 
 
 399. Paper shell. This piece is a paper shell filled 
 with decorative pieces, and fired from a common mortar. 
 It contains a small bursting-charge of powder, and has 
 a fuze regulated to ignite it when the shell reaches the 
 summit of its trajectory. 
 
 The shell is made by pasting several layers of thick 
 paper over a sphere of wood, cutting the covering thus 
 formed in halves, so as to remove the sphere, joining the 
 halves again, and pasting paper over them until the 
 thickness is sufficient to resist the charge of the mortar. 
 
 400. Decorative pieces. Decorative pieces are stars, 
 serpents, marrons, &c, described under the head of 
 rockets. . 
 
 401. For communicating fire. Preparations for com- 
 
GENEKAL KEMAKK. 381 
 
 municating fire from one piece to another are quick- 
 match, leaders, port-fires, and mortar-fuzes. 
 
 The leader is a thin paper tube containing a strand 
 of quick-match, and it is united to a piece by pasting 
 pieces of paper over the joint. If the piece is to be fired 
 at once, the leader may be omitted, and strands of quick- 
 match tied together used in its place. 
 
 402. General remark. The foregoing pieces are gen- 
 erally mounted on pieces or frames of light wood, and 
 are susceptible of being combined so as to produce a 
 great variety of striking effects. 
 
 a 
 
 
382 SCIENCE OF GUNNERY. 
 
 PART II 
 
 CHAPTER VIII. 
 SCIENCE OF GUNNERY. 
 
 The science of gunnery treats of the motion of pro- 
 jectiles, and of their effects. Ballistics is that branch 
 of the science of gunnery which treats of the motion of 
 projectiles. 
 
 403. History of ballistic*. Ancient artillerists consid- 
 ered that the trajectory, or path described by a projec- 
 tile after it left its piece, was composed of three distinct 
 parts: — 1st. The violent, which approached a straight 
 line. 2d. The middle, or mixed, which was a circle. 3d. 
 The last, or natural, which was also a right line. 
 
 Tartaglia, an Italian engineer, invented the quadrant 
 for measuring elevations, which he divided into twelve 
 parts, and by which he was able to compare the ranges 
 of different cannon, fired under the same or different 
 degrees of elevation. He demonstrated that no portion 
 of the trajectory was a right line, and that the angle 
 which gave the greatest range was 45°. 
 
 Galileo. About "£$#% Galileo discovered the laws 
 which govern the fall of bodies, and from these he dem- 
 onstrated that the curve described by a projectile, 
 thrown in a direction oblique to the horizon, is a pa- 
 rabola, the axis of which is vertical. He did not con- 
 
FUNDAMENTAL QUESTIONS. 383 
 
 sider that the air offered any material resistance to the 
 motion of artillery projectiles. 
 
 Newton. About 1723, Newton demonstrated that the 
 curve described by a spherical projectile in the air, was 
 far from being a parabola; that the two branches were 
 dissimilar, and that the descending branch would be- 
 come vertical if sufficiently prolonged. While he con- 
 sidered the resistance of the air proportioned to the 
 square of the velocity, he did not conceal the fact that 
 this was but an approximation to the true relation, 
 which remained to be determined by experiment. 
 
 Robins. About 1765, Robins invented an instrument 
 for determining the initial velocity of a projectile, called 
 the ballistic pendulum, by which he was able to show 
 that the range in vacuo was much greater than in air. 
 He also discovered that the rotary motion which spher- 
 ical projectiles generally assume around their centres 
 of gravity, will cause them to deviate from their true 
 direction. 
 
 Tlutton. Hutton, who lived about the beginning of 
 the present century, improved the ballistic pendulum, 
 and applied it to determine the true law of the resist- 
 ance of the air, as exemplified in projectiles of small 
 calibre. 
 
 At Metz, in 1839 and '40, further experiments were 
 made on the resistance of the air to projectiles of large 
 size, moving with high velocities, and the law of varia- 
 tion was determined with great accuracy. 
 
 INITIAL VELOCITY. 
 
 404. Fundamental questions The subject of ballis- 
 
384 SCIENCE OF GUNNERY. INITIAL VELOCITY. 
 
 tics presents two fundamental questions : 1st. To deter- 
 mine the initial velocity of a projectile for a known 
 piece and charge of powder. 2d. Knowing the initial 
 velocity and angle of projection, to determine the range, 
 time of flight, remaining velocity, and, in fact, all the 
 circumstances of the projectile's motion. 
 
 405. Definition of velocities The velocity of a pro- 
 jectile, at any point of its flight, is the space in feet, 
 passed over in a second of time, with a continuous, uni- 
 form motion. Initial velocity is the velocity at the 
 muzzle of the piece ; remaining velocity is the velocity 
 at any point of the flight ; terminal velocity is the ve- 
 locity with which it strikes its object ; Midi final velocity 
 of descent in air, is the uniform velocity with which a 
 projectile moves, when the resistance of the air becomes 
 equal to the accelerating force of gravity. 
 
 The initial velocity of a projectile may be determined 
 by the principles of mechanics which govern the action 
 of the powder, the resistance of the projectile, &c, or by 
 direct experiment. 
 
 406. By mechanical principles The instant that 
 the charge of a fire-arm is converted into gas, it exerts 
 an expansive effort which acts to drive the projectile 
 out of the bore. If the gaseous mass be divided into 
 elementary sections perpendicular to its length, it will 
 be seen that, in their efforts to expand, each section has 
 not only to overcome its own inertia, but the inertia of 
 the piece and projectile, as well as the inertia of the sec- 
 tions which precede it. The tension of each section, 
 therefore, increases from the extremities of the charge to 
 some intermediate point where it is a maximum. The 
 pressure on all sides of the section of maximum density 
 
PRACTICAL RULE TOR INITIAL VELOCITY. 385 
 
 being equal, it will remain at rest, while all the others 
 will move in opposite directions, constantly pressing 
 against the projectile and piece, and accelerating their 
 velocities. 
 
 As the projectile moves in the bore, the space, in 
 which the gases expand is increased, while their density 
 is diminished ; it follows that the force which sets a pro- 
 jectile in motion in a fire-arm varies from several causes ; 
 1st. It varies as the space behind the projectile increases, 
 or as the velocity regarded as a function of the time ; 
 2d. It varies throughout the column of gas for the same 
 instant of time ; and 3d. It varies from the increasing 
 quantities of gas developed in the successive instants of 
 the combustion of the powder. 
 
 Piobert has made the movement of a projectile in a 
 fire-arm the subject of a very elaborate analytical inves- 
 tigation, based on the mechanical principles of the con- 
 servation of the motion of the centre of gravity, living 
 forces, and Rumford's formula for the relation between 
 the density and pressure of fired gunpowder. 
 
 Formula for initial velocity. By supposing the weight 
 of the projectile to be nothing, compared to that of the 
 piece and carriage combined, that the tension of the 
 gases is proportional to the density, that the length of 
 the bore is sufficient for the entire charge to be con- 
 verted into gas, and that the projectile has no windage, 
 the complicated equations of Piobert may be reduced to 
 
 V—X x log — ; 
 
 in which F"is the initial velocity, X a constant to be de- 
 termined by experiment, m the weight of the powder, p 
 
386 SCIENCE OF GUNNEKY. INITIAL VELOCITY. 
 
 the weight of the projectile, and M the weight of pow- 
 der (loose) which would fill the bore. 
 
 The above value of V should be diminished for the 
 loss arising from windage ; the loss of force from wind- 
 age is directly proportional to the space between the 
 bore and projectile, and inversely- as the area of the 
 bore. Hence we have 
 
 C*-B 2 
 
 in which A is a constant to be determined by experi- 
 ment, C is the radius of the bore, and H the radius of 
 the projectile. For ordinary windage this may be re- 
 placed by 
 
 in which W is the windage, and the general expression 
 for the initial velocity becomes 
 
 There are three unknown quantities in this equation ; 
 V, A, and a ; V can be determined by direct experi- 
 ment for two or more charges of powder, and projectiles, 
 giving two equations containing the remaining unknown 
 quantities x and a. According to the experiments made 
 at the Washington arsenal with the ballistic pendulum, 
 the mean values of the co-eificients X and a, for Dupont's 
 powder in guns of various calibres (from 6-pdr. to 32-pdr.) 
 are: X =3500 feet, and A = 3200 feet. 
 
 M is equal to the gravimetric density of the powder 
 (referred to pounds and inches) multiplied by the vol- 
 ume of the bore. 
 
WHAT AFFECTS INITIAL VELOCITY. 
 
 387 
 
 Example. What is the initial velocity of a 6-pdr. shot fired with 
 a service-charge ? 
 
 m=1.25 lbs. ; p=6.25 lbs. ; (7=1.83 in ; W=.09 in. ; length of 
 bore, 57.5 in.; weight of a cubic inch of powder, 0.0293 lbs. 
 
 / 1.25 17.82 .09 
 
 F = 3500 V ftai+ii- lo g-r25- 3200 r^= 1444 - ft - 
 
 The mean of 11 fires with the 6-pdr. gun pendulum at West 
 Point, in November, 1860, was 1436.5 feet. 
 
 407. Practical rule for initial velocity. For the ordi- 
 nary purposes of practice, where the weight of the 
 powder and projectile alone vary, initial velocities may 
 be considered as directly proportional to the square root 
 of the weight of powder divided by the square root of the 
 weight of the projectile ; or 
 
 V • V /. • . • . ., V V . . 
 
 V m Vm! Vp rm 
 
 When V is known for a given charge of powder p' and 
 projectile m', the value of V can be obtained for any 
 other charge of powder, p y and projectile, m, of the same 
 calibre. This law however only holds true within cer- 
 tain limits, or when the powder is completely consumed 
 before the projectile leaves the piece.* 
 
 408. What affects initial velocity. The principal 
 
 * Table of Initial Velocities with service charges. 
 
 KIND OF CANNON. 
 
 6-pdr. field, 
 
 12-pdr. " 
 
 12-pdr. " howitzer,. 
 
 24-pdr. siege-gun, 
 
 8-inch siege howitzer, , 
 32-pdr. sea-coast gun,. 
 15-inch columbiad 
 
 CHARGE 
 
 KIND OF PROJECTILE. 
 
 OF 
 
 
 
 
 POWDER. 
 
 SHOT. 
 
 SHELLS. 
 
 sph'l case. 
 
 Lbs. 
 
 Feet. 
 
 Feet. 
 
 Feet. 
 
 1.25 
 
 1439 
 
 
 1357 
 
 2.50 
 
 1486 
 
 
 1486 
 
 1.00 
 
 
 1054 
 
 953 
 
 6.00 
 
 1680 
 
 1670 
 
 
 8.00 
 
 1870 
 
 
 
 4.00 
 
 
 907 
 
 
 8.00 
 
 1640 
 
 1450 
 
 
 40.00 
 
 
 1000 
 
 
 Note. — "When the initial velocities of shot, shells, and spherical-case shot are 
 given, the weight of the charge refers to the solid shot. 
 
388 SCIENCE OF GUNNERY. INITIAL VELOCITY. 
 
 causes which influence initial velocity, are the character 
 of the piece, powder, and projectile. Most of these have 
 been considered under their appropriate heads, in treat- 
 ing of the construction of cannon ; it will only be neces- 
 sary, therefore, to recapitulate them here. They are 
 the size and position of the vent, the windage, the 
 length of the bore, the form of the chamber, the diam- 
 eter and density of the projectile, the windage of the 
 cartridge, and the form, size, density, and dryness of 
 the grains of powder, and the barometric, thermometric, 
 and hygrometric states of the atmosphere. 
 
 It has been found by late experiments that the initial 
 velocity is unaffected by the angle of fire. Theoreti- 
 cally, varying the weight of the piece should exert an 
 influence on the initial velocity ; but, in consequence of 
 the great disparity of the weight of the piece and pro- 
 jectile, this influence is inappreciable in practice. 
 
 409. Determination of initial velocity by experiment. 
 A great variety of instruments have been invented to 
 determine directly the initial velocity of a projectile, the 
 most reliable of which are the gun-pendulum, the bal- 
 listic pendulum, and the electro-ballistic machines. 
 
 In the first, the velocity of the projectile is determined 
 by suspending the piece as a pendulum, and measuring 
 the recoil impressed on it by the discharge ; the expres- 
 sion for the velocity is deduced from the fact, that the 
 quantity of motion communicated to the pendulum is 
 equal to that communicated to the projectile, charge of 
 powder, and the air. The second apparatus is a pendu- 
 lum, the bob of which is made strong and heavy, to 
 receive the impact of the projectile; and the expression 
 for the velocity of the projectile is deduced from the 
 
THE WEST POINT BALLISTIC MACHINE. 389 
 
 fact, that the quantity of motion of the projectile before 
 impact is equal to that of the pendulum and projectile 
 after impact. These machines have been carried to 
 great perfection, both in this country and France, and 
 very accurate and important results have been obtained 
 by. them; but they are very expensive, and cannot be 
 easily adapted to the various wants of the service. 
 
 The employment of electricity to determine the veloc- 
 ity of projectiles, was first suggested by Wheat stone, in 
 1840. The application depends on the very great veloc- 
 ity of electricity, which, for short distances, may be 
 considered instantaneous. The general method of apply- 
 ing this agent is by means of galvanic currents, or wires, 
 supported on target frames, placed in the path of the 
 projectile, and communicating with a delicate time- 
 keeper. The successive ruptures of the wires mark on 
 the time-keeper the instant that the projectile passes 
 each wire, and knowing the distances of the wires apart, 
 the mean velocities, or velocities at the middle points, 
 
 can be obtained by the relation, velocity = -i . 
 
 J ' J time 
 
 The various plans in use differ only in the manner 
 
 of recording and keeping the time of flight ; one of the 
 
 simplest and most common instruments employed is 
 
 the pendulum. The ballistic machine of Captain Navez, 
 
 of the Belgian service, has been tried in this* country, 
 
 but has been found too delicate and complicated for 
 
 general purposes. 
 
 * In consequence of the variable nature of the resistance of the air, this mean 
 velocity does not strictly correspond to the middle point between the targets. The 
 difference, however, is very slight, as is shown by Captain Navez in the case of a 
 6-pdr. ball moving with an initial velocity of 600 meters, over a space of 50 meters; 
 the difference between the mean velocity and the velocity which it should have at 
 the middle point, is only 0.05 meter. 
 
390 
 
 SCIENCE OF GUNNEKY. INITIAL VELOCITY. 
 
 410. The We§t Point ballistic machine. Fig. 132 
 represents the front and end views of an electro-ballistic 
 machine originally devised by the author for the use of 
 the Military Academy, and since adopted by the ord- 
 nance department, for proving powder, &c. 
 
 Fig. 132. 
 
 a is a bed-plate of metal, which supports a graduated 
 arc (#). This arc is placed in a vertical position by 
 means of thumb-screws and spirit-levels attached to it ; 
 and it is graduated into degrees and fifths, commenc- 
 ing at the lowest point of the arc, and ending at 90°. 
 
 pp' are two pendulums having a common axis of 
 motion, passing through the centre, and perpendicular 
 to the plane of the arc. The bob of the pendulum p' 
 is fixed, but that of p can be moved up and down 
 with a thumb-screw, so as to make the times of vibra- 
 tion equal. 
 
 m and m are two electro-magnets attached to the 
 horizontal limb of the arc, to hold up the pendulums 
 when they are deflected through angles of 90°. 
 
 s and <?' are pieces of soft iron attached to the pro- 
 longations of the suspension-rods, in such way as to be 
 
THE WEST POINT BALLISTIC MACHINE. 391 
 
 in contact with the lower poles of the magnets, when 
 the pendulums are deflected. 
 
 d is an apparatus to record the point at which the 
 pendulums pass each other, when they fall by the 
 breaking of the currents which excite the magnets. It 
 is attached to the prolongation of the suspension-rod p\ 
 and consists essentially of a small pin enclosed in a 
 brass tube; the end of the pin near the arc has a sharp 
 point, and the other is terminated with a head, the sur- 
 face of which is oblique to the plane of the arc. As 
 the pendulums pass each other, a blunt steel point at- 
 tached to the lower extremity of the suspension-rod p, 
 strikes against the oblique surface of the head of the 
 pin, which presses the point into a piece of paper 
 clamped to the arc, leaving a small puncture to mark 
 the point of passage. To disengage the marking-point 
 from the paper, the tube containing the pin is free to 
 revolve through an angle of 90°, around a vertical axis, 
 in which revolved position it swings clear both of the 
 paper and the pendulum p. Tolerably strong paper 
 should be used in recording, to prevent the point from 
 tearing it. 
 
 cc and c'c represent the wires which conduct the 
 two currents that excite the magnets m and m. These 
 wires terminate in four clamp-screws secured to the bed- 
 plate, for the purpose of attaching the long wires lead- 
 ing through the batteries to the targets. 
 
 Targets. The targets are two frames of wood placed 
 so as to support the wires in a position to be cut by the 
 projectile. For the purpose of obtaining the initial ve- 
 locity, the first should be placed about 20 feet from the 
 muzzle of the piece, that the flame may not break the 
 
392 SCIENCE OF GUNNERY. INITIAL VELOCITY. 
 
 current before the projectile reaches it; the position of 
 the second depends on the velocity of the projectile. 
 For cannon, it should be placed about 100 feet from the 
 first target; and for small-arm and mortar projectiles, 
 about 50 feet. The number of times that the wire 
 should cross the targets depends on the size of the pro- 
 jectile and the accuracy of its flight. 
 
 Currents and batteries. The magnets should be made 
 of the purest attainable wrought iron, in order that 
 they shall retain no magnetic force after the exciting 
 currents are broken ; and for this purpose they are best 
 made of bundles of wire. The batteries should be of 
 nearly equal power and constancy, in order that, in case 
 the magnets do retain a portion of their magnetism, the 
 remaining portion may be as uniform as possible. 
 
 Grove's or Bunsen's batteries are the best that can be 
 used for this purpose. The power of the battery is 
 regulated by the distance of the targets and the size 
 of the conducting wires. If a weak battery be used, 
 the magnetic power may be increased by increasing the 
 diameter of the wire, or by resting pieces of soft iron 
 on the upper poles of the magnet. 
 
 In experimenting with cannon, the machine should 
 be placed about 120 yards from the piece, to prevent 
 any disturbance from the discharge; at this distance 
 the record will have been made before the sound reaches 
 the machine. For this distance, three cups, in which the 
 zinc cylinders are 8 inches long and 3 inches diameter, 
 and an insulated copper wire .06" diameter, have been 
 found to answer a good purpose. 
 
 The disjunctor. The disjunctor is a small auxiliary 
 instrument for closing and breaking the currents at will. 
 
THE WEST POINT BALLISTIC MACHINE. 393 
 
 It affords the means of verifying the accuracy of the 
 pendulum machine by a succession of simultaneous rup- 
 tures of the wires; when the machine is in good condi- 
 tion, the position of the point of meeting seldom varies 
 a tenth of a degree, an error which corresponds to only 
 .000154 of a second of time. 
 
 When the currents are of equal strength,, and the 
 starting points are properly adjusted, the point of meet- 
 ing will be found opposite to the zero of the grad- 
 uated arc ; if of unequal intensity, the point will be 
 found near the zero point and on the side of the 
 stronger magnet. As this position is nearly constant for 
 the same currents, the. error of the reading can be easily 
 corrected. If the error be positive, subtract it ; if nega- 
 tive, add it. 
 
 Arrangement, &c. Figure 133 shows the working 
 arrangement of the several pieces : a represents the pen- 
 dulum; b the disjunctor; c c and & c' 
 the currents; e e' the batteries; and 
 d the position of the gun. To operate 
 them, the disjunctor is closed, the 
 pendulums are deflected, the marking- 
 pin revolved perpendicular to the arc, 
 the piece is fired, and the position of Fi s- 133 - 
 
 the puncture in the paper, with reference to the grad- 
 uated arc, noted. 
 
 To determine the time. The velocity of the electric 
 currents being considered instantaneous, and the loss of 
 power of the magnets simultaneous with the rupture of 
 the currents, it follows that each pendulum begins to 
 move at the instant that the projectile cuts the wire, 
 and that the interval of time corresponds to the differ- 
 
394 SCIENCE OE GUNNERY. INITIAL VELOCITY. 
 
 ence of the arcs described by the pendulums up to the 
 time of meeting. 
 
 Let m andm', fig. 134, represent the positions of the 
 two magnets, and let the interval between the rupture 
 be such that the centres of oscilla- 
 tion will pass each other at i. As 
 the times of vibration are equal, the 
 interval of time will correspond to 
 the arc i i\ the arc rn! i being equal Fi e- 13 ±. 
 
 to m i'. A vertical line through the centre of motion 
 bisects the arc i i . The reading therefore corresponds 
 to one-half of the required time, or time of passage of 
 the projectile between the wires. 
 
 To determine a formula for the time that it takes for 
 one of the pendulums to pass over a given arc, let I be 
 the length of the equivalent simple pendulum, v the 
 velocity of the centre of oscillation or point m\ y the 
 vertical distance passed over by this point, x the vari- 
 able angle which the line of suspension makes with the 
 horizontal, and t' the time necessary for the point m' to 
 pass over an entire circumference, the radius of which 
 is Z, with a uniform velocity v, we have, 
 
 v=V2gy. . 
 Substituting for y its value in terms of the constant 
 angle of half-oscillation and the variable angle a?, the 
 above expression becomes, 
 
 v=vl>gl cos. (90°— a) ; 
 from which we see that the velocity of the pendulum 
 increases from its highest to its lowest point, and vice 
 versa. 
 
 The time t' is equal to the circumference of the circle, 
 the radius of which is Z, divided by the velocity, v; 
 
THE WEST POINT BALLISTIC MACHINE. 395 
 
 again divide this by 360, we have the time of passing 
 over each degree, or, 
 
 t=z 2j 
 
 S60i/2gl cos.(90°— 5) • 
 
 To determine £, it is necessary to change the cylin- 
 drical arms of suspension to knife-edges, in order to de- 
 termine the time of vibration through a veiy small arc. 
 The mean of 500 vibrations will be very near the exact 
 time of a single vibration. Knowing the time of a 
 single vibration, the length of the equivalent simple 
 pendulum can be obtained by the relation l=d't"*, in 
 which t" is this time, and V is the length of the simple 
 second's pendulum at the place of observation. 
 
 At West Point Z'=:39.11448 inches. 
 " " ^=32. 17050 feet. 
 
 In this way all the constants of the expression for t 
 are known, and by assigning different values to a?, a 
 table can be formed, from which the times corresponding 
 to different arcs can be obtained by simple inspection. 
 The table in chapter XIII. is calculated for the West 
 Point machine. y 
 
 MOTION OF A PROJECTILE IN VACUO. 
 
 411. Determination of equation§ of motion. A 'pro- 
 jectile is a body thrown or impelled forward, generally 
 in the air ; and the trajectory is the line described by 
 its centre of inertia. The movement of a projectile will 
 be considered firstly in vacuo, and secondly in the air. 
 
 Let A (fig. 135) be the position of the muzzle of a 
 fire-arm, and the line A B its axis prolonged. 
 
396 SCIENCE OF GUNNERY. MOTION IN VACUO. 
 
 Fig. 135. 
 
 Let <P represent the angle which this line makes with 
 the horizontal plane, or the angle of projection. 
 
 V the initial velocity. 
 
 v the velocity at the point m. 
 
 t the time of flight to the same point. 
 
 6 the inclination of the tangent at this point. 
 
 #, y, the co-ordinates of this point. 
 
 JTthe horizontal range. 
 
 Y the greatest height of ascent. 
 
 T the whole time of flight, or for the range X. 
 
 If the projectile were only acted upon by the force of 
 the discharge, it would move in the straight line A £, 
 and after a time, t, would reach the point P ; but it is 
 constantly drawn to the earth by the force of gravity, 
 and instead of being found at the point P, it is found 
 at the point m, situated at a distance below P equal to 
 the distance which it would fall in the same time under 
 the influence of gravity, or \gt 2 , g being the velocity 
 generated by gravity in a second of time. 
 
 The distance PC is equal to x tan. <£; the distance 
 
 mCj or y, is equal to this distance diminished to ±gt 2 , or, 
 
 y=#tan. <p-\gt 2 ) 
 
 x 
 x=t l^cos. £, or t=-y • Substituting this for t in 
 
 the preceding equation, it becomes, 
 
 g x 2 
 
 y=x tan <f>- 
 
 2 F 2 cos. 2 
 
MOTION IN VACUO. 397 
 
 From the laws which govern falling bodies, F== 
 
 V'lgH, or V 2 —^gH; in which H is the height due 
 to the velocity V. Substituting this value of V 2 , the 
 
 equation becomes, 
 
 x 2 
 
 y=x tan. $—-7-7? r*~i (1) 
 
 y r 4:B cos. 2 </>' v J 
 
 which is the equation of a parabola. 
 From the same figure we obtain — 
 
 y=Vt sin. <t>-igt 2 . (2) 
 
 #= Vt cos. </>. (3) 
 
 *= ® „ . (4) 
 
 K COS. v 7 
 
 2d. To determine the vertical ascent and horizontal 
 range of the projectile, differentiate equation (1), and 
 
 place the value of -^=0; whence we obtain, 
 dx 
 
 X— 4 Hsin.<t> cos.tf>=: 2 J7 sin. 20. (5) 
 
 ^ X being the abscissa of the highest point, 
 
 Y"=^ r sin>. (6) 
 
 The first value of X shows, that the range can he ob- 
 tained with two angles of projection, provided they be 
 complements of each other ; the second value shows, that 
 the greatest range corresponds to an angle of 45°, and 
 that this range is equal to twice the height due to the ve- 
 locity ; and, also, that variations in the angle of fire 
 produce less variations in range as the angle of fire ap- 
 proaches 45°. 
 
 3d. If two projectiles be thrown under the same angle, 
 
 with different initial velocities, V and V\ the ranges 
 
 being X and X \ we have, 
 
 Y 2 V' 2 
 
 X=2#sin.20= — sin. 20, and X'— sin. 20; 
 
 9 9 
 
398 SCIENCE OF GUNNERY. MOTION IN VACUO. 
 
 and from these we nave, 
 
 V _<^ (7) 
 
 Therefore, under the same angle of fire, the ranges are 
 proportional to the squares of the velocities ; and recip- 
 rocally, the velocities are proportional to the square roots 
 
 of the ranges. 
 
 ds 
 4th. The velocity at any point is equal to -j, or 
 
 du 2 -\-dx 2 
 v*=-^—j-2 — . Substituting the values of dy and dx, 
 
 obtained by differentiating equations (2) and (3), we 
 
 have 
 
 v*= V 2 -2 Vgtsm.<t>+gH 2 . 
 
 Substitute for -2 Vgt&m.<P+gH 2 its value -2gy, de- 
 rived from equation (2), we have, 
 
 v 2 = V 2 -2gy. 
 Keplace V 2 by 2gH, and reducing, the expression be- 
 comes, 
 
 v=V2g(H-y). (8) 
 
 This shows that the velocity of a projectile, at any 
 point, depends on its height above the muzzle of the piece / 
 and that it is equal to that which is attained in falling 
 through the height (H—y). It also shows that the ve- 
 locity is least when y is greatest, or at the summit of the 
 trajectory ; and that the velocities at the two points in 
 which the trajectory cuts the horizontal plane are equal. 
 
 5th. The total time of flight may be determined by 
 substituting the value of X— 4i^sin.4>cos.<£, equation 
 (5), in equation (4), which becomes 
 
 4j£Tsin.</)_ Fsin.^ (9) 
 
MOTION IN VACUO. 399 
 
 If </>=45°, sm.cp=V% 1 and V=VgX. Calling T the 
 time of flight, we have, 
 
 ' V \q V 16.07 T 
 
 Hence the time of flight for an angle of 45° is equal 
 to the square root of the quotient of the range divided by 
 one-half of the force of gravity ; or, it is approximately 
 equal to one-fourth of the square root of the range ex- 
 pressed in feet 
 
 6th. The tangent of the angle made by a tangent 
 
 line at any point of the trajectory is equal to -X which 
 
 is obtained by differentiating equation (1) ; calling this 
 
 angle 0, we have, 
 
 x 
 
 tan.(9=tan.w> == . (10) 
 
 r 2^cos. 2 tf> v J 
 
 Substitute the value of JT=4 H sin.^ cos.0, the angle 
 of fall on horizontal ground is tan.0= — tan.0 ; that is to 
 say, the angle of fall is equal to the angle of projection, 
 measured in an opposite direction. 
 
 7th. The position of a point being given, to find the 
 initial velocity necessary to attain it, let a and b be the 
 horizontal and vertical co-ordinates of this point of the 
 curve, and e its angle of elevation. Substituting these 
 quantities in equation (1), and recollecting that tan. 
 
 e= -, we have, 
 a 
 
 a COS.e 
 
 H- 
 
 4 sin. (<£ — e)- cos.0' 
 
 or, 7=4 / ■ , a 9 c °^ . (11) 
 
 V 2 sin.(<2>— eVcos.o!) 
 
400 SCIENCE OF GUNNERY. INITIAL VELOCITY. 
 
 8th. The position of a point being given, to find the 
 angle of fire necessary to attain it. Substituting a and 
 b for x and y in equation (1), we have, 
 
 ~ 9 
 
 b=a tan.^. 
 
 4i7cos. 2 
 from which to determine </>. 
 
 Making tan.<£=a, we have, cos. 2 <£ = ; which be- 
 ing substituted in the above equation gives— 
 
 a=tan.0=:-(2^r = Li/4S' T ^4^3^y (12) 
 
 The two values of tan.^ show that the point may be 
 attained by two angles of projection; and the radical 
 shows the solution of the problem is possible when the 
 quantity under it is positive / or, 
 
 4:H 2 >4:JIb+a\ 
 
 412. Practical application of formula. The preced- 
 ing formula will only be found to answer in practice for 
 projectiles which experience slight resistance from the 
 air, or for heavy projectiles moving with low velocities, 
 as is commonly the case with those of mortars and 
 howitzers. 
 
 The following table gives the difference between the 
 observed and calculated times of flight of the French 8 
 and 10-inch mortar shells, weighing 64 and 119 lbs. 
 respectively. The initial velocities being unknown, the 
 times are calculated from the observed ranges. 
 
 The observed times are invariably greater than the 
 calculated times, as might be expected from the resist- 
 ance of the air, which retards the motion of projectiles. 
 
PRACTICAL APPLICATION OF FORMULA. 
 
 401 
 
 Kind of 
 projectiles. 
 
 ■fi.'S 
 
 "S3 o 
 
 Ranges at angles of 
 
 Times of flight. 
 
 4 
 
 5° 
 
 30° 
 
 45° 
 
 30° 
 
 Observed. 
 
 Calcu- 
 lated. 
 
 Observed. 
 
 Calcu- 
 lated. 
 
 
 Kilog. 
 
 0.234 
 
 Meters. 
 
 343 
 
 Meters. 
 
 290 
 
 Seconds. 
 
 9.8 
 
 Seconds. 
 
 8.4 
 
 Seconds. 
 
 6.8 
 
 Seconds. 
 
 5.8 
 
 8-inch. 
 
 0.351 
 0.585 
 
 629 
 1146 
 
 561 
 1011 
 
 12.9 
 16.0 
 
 11.3 
 15.3 
 
 10.0 
 12.3 
 
 8.1 
 10.9 
 
 
 0.994 
 
 1792 
 
 1690 
 
 20.8 
 
 19.2 
 
 16.9 
 
 14.1 
 
 
 0.468 
 
 457 
 
 383 
 
 11.0 
 
 9.7 
 
 7.5 
 
 6.8 
 
 
 0.693 
 
 734 
 
 637 
 
 14.0 
 
 12.2 
 
 10.0 
 
 8.7 
 
 10-inch. 
 
 1.054 
 
 1132 
 
 980 
 
 17.0 
 
 15.2 
 
 12.0 
 
 10.2 
 
 
 1.405 
 
 1555 
 
 1355 
 
 20.0 
 
 17.8 
 
 14.0 
 
 12.6 
 
 
 1.639 
 
 1757 
 
 1516 
 
 23.0 
 
 18.9 
 
 15.0 
 
 13.4 
 
 The next table shows the observed and calculated 
 ranges, for 30° elevation, and the observed ranges for 
 45° elevation, for the above projectiles, the initial veloc- 
 ities being the same for each projectile. 
 
 Kanges 
 
 of 10-inch Mortar Shells. 
 
 Ranges of 8-inch Mortar Shells. 
 
 45° 
 
 30° 
 
 45° 
 
 30° 
 
 elevation. 
 
 elevation. 
 
 elevation. 
 
 elevation. 
 
 
 
 Calcu- 
 
 
 
 
 Calcu- 
 
 
 Observed. 
 
 Observed. 
 
 lated. 
 
 Difference 
 
 Observed. 
 
 Observed. 
 
 lated. 
 
 Difference 
 
 Meters. 
 
 Meters. 
 
 Meters. 
 
 Meters. 
 
 Meters. 
 
 Meters. 
 
 Meters. 
 
 Meters. 
 
 457 
 
 383 
 
 396 
 
 + 13 
 
 343 
 
 290 
 
 298 
 
 + 8 
 
 734 
 
 637 
 
 637 
 
 
 
 629 
 
 561 
 
 545 
 
 —16 
 
 1132 
 
 980 
 
 982 
 
 + 2 
 
 1146 
 
 1011 
 
 993 
 
 —13 
 
 1555 
 
 1355 
 
 1350 
 
 — 5 i 
 
 1792 
 
 1690 
 
 1552 
 
 —138 
 
 1757 
 
 1516 
 
 1522 ■ 
 
 + 6 
 
 
 
 
 
 It appears from the foregoing tables, that the ranges 
 of mortars with different degrees of elevation, can be 
 calculated up to about 1,400 yards from equation (5), 
 
 or, 
 
 26 
 
 X=2^ r sin. 20, 
 
402 SCIENCE OF GUNNERY. RESISTANCE OF THE AIR. 
 
 and the times from equation (4), or 
 
 X 
 
 T= 
 
 T^COS. <j> 
 
 RESISTANCE OF THE AIR. 
 
 413. Importance of considering it. A body moving 
 in the air experiences a resistance which diminishes the 
 velocity with which it is animated. That the retarding 
 effect of the air, on projectiles moving with high veloc- 
 ities, is very great, is seen by comparing the actual 
 ranges of projectiles with those computed under the 
 supposition that they move in vacuo. Thus, it has been 
 shown that certain cannon-balls do not range one-eighth 
 as far in the air as they would if they did not meet 
 with this resistance to their motion; and small-arm 
 projectiles, which have but little mass, are still more 
 affected by it. 
 
 414. Law of resi§tance. Incompressible fluid. The 
 resistance experienced by a plane surface moving parallel 
 to itself through an incompressible fluid, is equal to the 
 pressure of a column of the fluid, the base of which is 
 the moving surface, and its height that due to the ve- 
 locity with which the surface is moved through the 
 
 fluid, or, from the law of falling bodies, h= • in 
 
 y 
 which h is the height, v the velocity, and g the force of 
 
 gravity. 
 
 The resistance on a given area is therefore propor- 
 tional to the square of the velocity, and the density of 
 the fluid medium. 
 
 Let d, «9J and v represent the density or weight of a 
 
LAW OF EESISTANCE. 403 
 
 unit of volume of the fluid, the area pressed upon, and 
 the velocity of the moving surface, respectively, and p the 
 resistance in terms of the unit of weight, and we have, 
 
 9=MS^ (13) 
 
 in which h is a coefficient to be determined by experi- 
 ment. 
 
 Compressible fluid. If the medium be formed of com- 
 pressible gases, as the atmosphere, the density in front 
 of the moving body will be greater than that behind it ; 
 and it will be readily seen that the body will meet with 
 a resistance which increases more rapidly than the square 
 of the velocity, in such a manner that the coefficient \ 
 or the density of the medium, d, should be increased by 
 a quantity which is a function of the velocity itself, or, 
 what is the same thing, by adding another term to the 
 resistance which shall be proportional to the cube of the 
 velocity. 
 
 In examining the table of resistances, obtained by 
 Hutton from firing a one-pound ball into a ballistic pen- 
 dulum, at different distances, and with velocities vary- 
 ing from 300 to 1,900 feet, Piobert found, that if v 2 in 
 the foregoing expression be replaced by the binomial 
 
 term, ( v 2 -\ — i, m which -—_ , the expression 
 
 would nearly satisfy the results of experiments. 
 
 hd 
 Calling A= — , and ttR* the area of the cross section 
 
 of a projectile, the general expression for the resistance 
 in air becomes, 
 
 9 =AnB>(l+f)v\ (14) 
 
\ 
 
 404 SCIENCE OF GUNNERY. RESISTANCE OF THE AIR. 
 
 In this expression, A is the resistance, in pounds, on 
 a square foot of the cross-section of a projectile moving 
 with a velocity of one foot; r is a linear quantity de- 
 pending on the velocity of the projectile. For all service 
 spherical projectiles, ^4. =.000514; and for all service 
 velocities 7*= 1427 feet. The value of A for the oblong 
 projectiles of our service remains to be determined by 
 experiment; it is stated in the French Aide-Memoire 
 that for a certain oblong bullet (presumed to be that of 
 the carabine a tige) ^.=.000342, or that the resistance 
 of the air is one-third less on the pointed than on the 
 spherical form. 
 
 The coefficient A, being a function of the density of 
 the air, its value depends on the temperature, pressure, 
 and hygrometric condition ; in the above value the 
 weight of a cubic foot of air =.075 lb., at a temperature 
 of 60° Fahr., and for a barometrical pressure of 29.5 
 inches. 
 
 If the surface of the projectile be rough or irregular, 
 the value of this coefficient will be slightly too small. 
 
 Example. — What is the pressure of the air on a 42-pdr. shot 
 moving with a velocity of 1,500 feet? 
 
 — 2 ,/ 1500\ 
 
 p=.000514 X 3.1415 x .29 X 1500 2 ( 1 + — - I =629.3 lbs 
 
 / 150o\ 
 ( 1 + l427j 
 
 415. Fall of a projectile In the air. The motion of 
 a body falling through the air, will be accelerated by 
 its weight, and retarded by the buoyant effort of the 
 air, and the resistance which the air offers to motion. 
 As the resistance of the air increases more rapidly than 
 the velocity, it follows that there is a point where the 
 retarding and accelerating forces will be equal, and that 
 beyond. this, the body will move with a uniform veloc- 
 
FALL OF A PROJECTILE IN THE AIR. 405 
 
 ity, equal to that which it had acquired down to this 
 point. 
 
 The buoyant effort of the air is equal to the weight 
 
 of the volume displaced, or P— ; in which P is the 
 
 weight and D the density of the projectile, and d the 
 density of the air. 
 
 When the projectile meets with a resistance equal to 
 its weight, we shall have, 
 
 P(l-§)=^v(l+^); (15) 
 
 in which the weight of the displaced air is transferred 
 to the first member of the equation. As the density 
 of the air is very slight compared to that of lead or 
 
 iron, the materials of which projectiles are made, ~> 
 
 may be neglected. Making this change, and substitu- 
 
 4 
 ting for P, —nil 3 1) (g having been divided out of the 
 
 o 
 
 second member, should be omitted in the first), the ex- 
 pression for the final velocity reduces to 
 
 The resistance on the entire projectile for a velocity 
 
 P 
 
 of 1 foot, is AttR 2 ; dividing this by — , or the mass, we 
 
 if 
 
 get the resistance on a unit of mass. 
 
 Calling this — , we have, 
 
 zc 
 
 1 AnB? a P 
 
 9 
 
406 
 
 SCIENCE OF GUNNERY. LOSS OF VELOCITY. 
 
 Substituting for P its value in the equation of verti- 
 cal descent, we have, 
 
 2^=* 2 (i+^); 
 
 from which we see that v depends only on c / but 
 
 2 ED 
 
 €= 
 
 3 gA 
 
 (17) 
 
 hence, the final velocity of a projectile falling through 
 the air is directly proportional to the product of the 
 diameter and density of the projectile, and inversely 
 proportional to the density of the air, which is a factor 
 of A. 
 
 
 SHOT. 
 
 SHELLS. 
 
 MUSKET 
 BULLET. 
 
 Calibre 
 
 42 
 
 24 
 
 18 
 
 12 
 
 6 
 
 13 in 
 
 10 in 
 
 8 in. 
 
 24 
 pdr. 
 
 Round, 
 69 diam. 
 
 
 Final velocity of de- 
 scent in air, in feet 
 per second 
 
 485 
 
 455 
 
 425 
 
 410 
 
 360 
 
 585 
 
 505 
 
 445 
 
 375 
 
 213 
 
 Value of c 
 
 4899 
 
 4247 
 
 3650 
 
 3370 
 
 2518 
 
 6436 
 
 4677 
 
 3570 
 
 2754 
 
 804 
 
 
 
 
 
 The value (<?) may be said to represent the relative 
 ability of a projectile to overcome the resistance of the 
 air. 
 
 LOSS OF VELOCITY BY EESISTANCE OF 
 THE AIR 
 
 416. Equation§ of motion. For the purpose of de- 
 termining the velocity which a projectile loses by the 
 resistance of the air, in moving through a certain dis- 
 tance, 00j the force of gravity may be disregarded ; in 
 which case the trajectory described will be a right line. 
 
LOSS OF VELOCITY BY THE AIR. 407 
 
 Let V be the initial velocity, and v the remaining ve- 
 locity at the end of the distance a?. 
 
 The expression for the resistance of the air is, as we 
 have seen, 
 
 But we know that the retarding force of the air is equal 
 to the mass of the projectile against which it acts, multi- 
 plied by the first differential coefficient of the velocity, 
 regarded as a function of the time, with its sign changed, 
 
 and that — is the mass of the projectile. We have, 
 therefore, 
 
 Eecollecting that jP=-7riJ 3 Z>, and that 2c= -p, the 
 
 equation reduces to, 
 
 dv_ v 2 / v\ 
 
 Integrating this equation between the limits and %, 
 which correspond to V and v, we have, 
 
 T 
 
 + V 
 To obtain a relation between the space and velocity. 
 
 we have v—-j-i ovdt— — ; substituting this in the equa- 
 tion for the intensity of the retarding force, and reduc- 
 ing, we have, 
 
 dv 
 
 A 1\ 2c, ' v. 
 
 \v-v)-T l °^--r (18) 
 
 dx=: — 2c 
 
 V 
 
 H) 
 
408 SCIENCE OF GUNNERY.— LOSS OF VELOCITY. 
 
 Integrating between the same limits as in the preced- 
 ing case, we have, 
 
 r x 
 
 1 + 
 
 2c 
 
 x=2clog. -or l+£sjflHrjfV 
 
 (19) 
 
 T 
 
 1+ V 
 
 Solving this equation with reference to v, we have, 
 
 r 
 
 v= 
 
 ('+T>*- 
 
 (20) 
 
 Substituting, in equation (18), x for its value given 
 in equation (19), we have, 
 
 t=2c ( l *\- X . (21) 
 
 The logarithms in the above equations belong to the 
 Napierian system, and are obtained by multiplying the 
 corresponding common logarithm by 2.3026:0=2.713. 
 
 Practical remarks. Equation (19) gives the space 
 passed over by a certain projectile when the velocities 
 at the commencement and end of the flight, are known. 
 
 Equation (20) gives the remaining velocity when the 
 initial velocity and the space passed over are known. 
 
 Equation (21) gives the time of flight when the ve- 
 locities at the beginning and end and the space passed 
 over, are known. 
 
 The distance at which the velocity Fls reduced to t\ 
 and the duration of the trajectory, being proportional to 
 c, are directly proportional to the product of the diame- 
 ter and density of the projectile, and inversely propor- 
 tional to the density of the air. This fact shows the 
 great advantage, in point of range, to be derived from 
 
THEORY. 409 
 
 using large projectiles over small ones, of solid projec- 
 tiles over hollow ones, of leaden projectiles over iron 
 ones, and of oblong projectiles over round ones. 
 
 FORM OF PROJECTILE. 
 
 417. Theory. When a body moves through the air, 
 the gaseous particles in front are crowded upon each 
 other until they meet with a certain resistance, after 
 which they move off laterally, and finally pass around 
 and arrange themselves in rear of the moving body. 
 It is evident that the difference of the densities, or 
 pressures, front and rear, depends on the velocity with 
 which the displaced particles rearrange themselves after 
 displacement ; and this, in turn, depends on the shape, 
 and extent of the surfaces of the moving body. The 
 best form for a projectile can only be determined by ex- 
 periment, as theory and experiment do not agree in 
 their results. 
 
 According to theory, if a plane of given area be 
 moved through the air, it meets with a resistance 
 which is proportional to the square of the sine of the 
 ans4e which its direction makes with that of motion. 
 
 The experiments of Hutton with low velocities show 
 that this is only true in cases of 0° and 90° ; that from 
 90° up to 50° or 60°, the resistance is nearly propor- 
 tional to the sine ; beyond this, it decreases a little more 
 rapidly than the sine, but not so rapidly as the square 
 of the sine : 
 
410 
 
 SCIENCE OF GUNNERY. LOSS OF VELOCITY. 
 
 For an angle of 22° it is only \ the resistance proportional to the sine. 
 
 a U 14.0 a \_ u ►< u 
 
 3 
 
 « « Qio "1 " ** M 
 
 tt U 40 « 1 M « U 
 
 * 5 
 
 « U 0° << 1 « " U 
 
 418. Experiments of Hutton and Borda. The fol- 
 lowing are the results of the experiments made by 
 Hutton and Borda, on the resistances experienced by 
 different forms of solids moving through the air with 
 velocities varying from 3 to 25 feet per second. 
 
 HUTTON 1 S EXPERIMENTS. VELOCITY, 10 FEET. 
 
 
 Kind of surface. 
 
 Experimental 
 resistance. 
 
 Theoretical 
 resistance. 
 
 
 | 
 
 
 No. 1 Hemisphere (convex 
 
 surface in front), 
 No. 2 Sphere, 
 
 No. 3 Cone, elements in- 
 clined to the axis 25° 42', 
 No. 4 Disk, 
 
 No. 5 Hemisphere (plane 
 
 surface in front), 
 No. 6 Cone (base in front), 
 
 119 
 
 124 
 
 126 
 
 285 
 
 288 
 291 
 
 144 
 144 
 
 53 
 
 288 
 
 288 
 288 
 
 
 Fig. 136. 
 
 
 BORDA. 
 
 
 Kind of surface. 
 
 Experimental 
 resistance. 
 
 Theoretical 
 resistance. 
 
 
 | 
 
 
 No. 1, Prism, with triangular 
 
 base, 
 No. 2, " M 
 
 No. 3, " semi-ellipse, 
 
 No. 4, " ogee, 
 
 100 
 52 
 
 43 
 
 39 
 
 100 
 25 
 
 50 
 
 41 
 
 
 Fig. 137. 
 
CONCLUSIONS. 411 
 
 419. Conclusions The foregoing experiments show: 
 1st. That the results of theory do not agree with those 
 of practice. 2d. That rounded and pointed solids suffer 
 less resistance from the air than those which present 
 flat surfaces of the same transverse area, but, at the 
 same time, the sharpest points do not always meet with 
 the least resistance. 3d. That where the front surfaces 
 were the same, the resistance was least with those in 
 which the posterior surfaces were the flattest. 4th. 
 That the ogeeval form, or the form of the present rifle- 
 musket bullet, experiences less resistance than any other 
 tried. 
 
 These experiments, as before remarked, were made 
 with low velocities, compared to those which ordinarily 
 actuate projectiles, and the conclusions which have been 
 drawn from them may not be strictly applicable in prac- 
 tice. Now that oblong projectiles are used in all kinds 
 of fire-arms, it is important to determine that form which 
 will be least affected by the resistance of the air. It is 
 evident that that form will be the best which, on trial, 
 is found to give the least value to A in equation (14), 
 or, what is the same thing, to give the greatest value to 
 c in equation (21).* 
 
 * The author proposes the following method of determining the value of c by the 
 electro-ballistic machine. 
 
 Establish four targets in the line of fire, in such manner that the first shall be 
 near the piece, the second shall be at a distance x from the first, the third at a 
 distance 2x from the first, and the fourth at a distance of 4x from the first ; let t, t\ 
 and t" represent the intervals of time corresponding to the distances between the 
 targets, respectively; let v be the velocity at the middle point between the first 
 and third targets, or at the distance x, and let v' be the velocity at the middle point 
 between the first and fourth targets, or at the distance 2x. 
 
 Equation (21) becomes 
 
 2c 2e X or 2^ = 2c_^_ # 
 v V r V v r 
 
412 SCIENCE OF GUNNERY. TRAJECTORY IN AIR. 
 
 TRAJECTORY IN AIR. 
 
 420. Bifflcuitie§ of the problem. In consequence of 
 the variable nature of the resistance of the air, it has 
 been found impossible to integrate the differential equa- 
 tions of the real trajectory, even under the supposition 
 that this resistance varies in as simple a ratio as the 
 square of the velocity. Several distinguished mathe- 
 maticians have obtained expressions which approximate 
 to the true results, but the expressions are generally too 
 complicated to be of much practical value. 
 
 421. Diction's method. Captain Didion, professor 
 of gunnery in the artillery school at Metz, however, 
 furnishes an approximate solution to this difficult ques- 
 tion, which may be used in practice. To do this, he 
 considers the resistance of the air equal to 
 
 Mffft+tyf; 
 
 and by assuming a mean value for the different inclina- 
 tions of the elements of the trajectory to their horizon- 
 
 ds 
 tal projections, which makes -r- constant, he is able to 
 
 2 c 
 Since ■— is the same for all the distances, we have 
 
 t—t'—~ 
 2c fit 2c 2x , r 
 
 f— r 1, or c— -jz -— 
 
 v r v r 2 
 
 From the note on page 389, we are at liberty to place v— =— and v'— ■— • substitut- 
 
 t t 
 
 ing these values in the preceding equation, reducing and changing the signs of both 
 numerator and denominator of the second member, we have 
 
 2x1 f—t+~ 
 c- 
 
 t"—2t' 
 
 "Which equation gives the value of c in terms of t, t', t", and which can be deter- 
 mined by taking the mean of several shots, with the electro-ballistic machine, at 
 the different distances, x, 2x, and 4x. 
 
413 
 
 integrate the differential equations, and place them un- 
 der the following forms : 
 
 ft fl$ 
 
 y=x tan. (j> —~ -« r B ; 
 
 * 2 V 2 cos. 2 \ 
 
 OS 
 
 Tan. d= tan.0 — a-™ tt.1; 
 
 X -r. T^COS. 1 
 
 t= «r- JJ ; v=. yt- 
 
 V cos. <$> 7 cos. e U 
 
 The same notation being preserved as in the equa- 
 tions in vacuo (page 397), it will be perceived that the 
 equations in air differ from those in vacuo, by the mul- 
 tipliers B, I, ./>, and U, respectively. 
 
 The multiplier B relates to the fall of the projectile ; 
 7, to the inclination ; Z>, to the duration ; and U, to the 
 
 velocity ; they are each functions of — and — -; in 
 
 which a is the constant relation of the arc to its projec- 
 tion, V,= 7^ cos. 0, and c and r are co-efficients of the 
 formula for the resistance of the air. (See pages 403 
 and 406.) The general expression for a particular mul- 
 tiplier, B for instance, is B( — ; - — - V 
 
 The values B, I, D, and TJ % for such values of c and 
 r as are likely to arise in service, have been computed, 
 and arranged in tabular form ; these tables, their con- 
 struction, and use, are explained in chapter XIII. 
 
 So long as the inclination of the trajectory is slight, « 
 differs but slightly from unity; for an angle of 15° it 
 does not exceed 0.01 ; and as it only enters into the 
 term which relates to the resistance of the air, the error 
 
414 SCIENCE OF GUNNERY. TRAJECTORY IN AIR. 
 
 does not exceed a pressure corresponding to 0.25 in. in 
 the height of the barometer ; it may, therefore, be re- 
 
 garded as unity, and — - reduces to -. The same with 
 
 G G 
 
 regard, to — — • or — ; as a cos. tj>, when 0=10°, 
 
 differs only about 0.01 from unity ; and this expression 
 
 y 
 
 may be reduced to — . When the angle of projection 
 
 does not exceed 3°, cos. <p differs only .001 from unity, 
 and we can everywhere replace V cos. by V. Under 
 
 COS 
 
 this angle, — — differs but slightly from unity, and we 
 
 V 
 have v= — f which is the same as if motion took place 
 
 in a horizontal plane. 
 
 All cases of the movement of projectiles which occur 
 in practice, may be divided into three distinct classes : 
 1st, When the angle of projection is slight, or does not 
 exceed 3°, as in the ordinary fire of guns, howitzers, and 
 small-arms ; 2d, When the angle of projection is greater 
 than this, but does not exceed 10° or 15°, as in ricochet 
 fire, &c. ; 3d, When the angle of projection exceeds 15°, 
 as in the fire of mortars. 
 
 422. l§t class. For small angles of projection, as in 
 guns, howitzers, and small-arms. 
 
 For slight variations of the angle of projection above 
 or below the horizon, the form of the trajectory may be 
 considered constant ; and when the object is but slightly 
 raised above, or depressed below the horizontal plane, 
 it may be considered as in this plane. 
 
 In consequence of the windage, and the balloting of 
 
FIEST CLASS. 415 
 
 the projectile which results from it, the projectile does 
 not always leave the bore in the direction of the axis. 
 The angle formed by the line of departure and the axis 
 of the piece, is called the angle of departure. For guns 
 in good condition, the vertical deviations do not exceed 
 5', and for howitzers 10'; the side deviations never ex- 
 ceed 4' 30". To obtain exact results, therefore, it is 
 necessary to correct the angle of projection for the angle 
 of departure, when the latter is known. 
 
 T- 1 T .... -, COS.0 
 
 Under the supposition that a, cos. </>, and are 
 
 each equal to unity, the equations of the trajectory in 
 air may be reduced to — 
 
 r=»***-fii*; ( 22 ) 
 
 Tan.0=tan.0-gr * /; (23) 
 
 teyD; (24) 
 
 v=^. (25) 
 
 Knowing the weight and diameter of the projectile, c 
 
 can be calculated by the formula c=~- — if it be 
 
 SgA 
 
 not found in the table which accompanies it. We 
 
 x V 
 
 know - and — , and by means of the tables can deter- 
 
 c r 
 
 mine the desired values of B, I, D, and TI. 
 
 Of the three things, the initial velocity, J 7 ", the dis- 
 tance of the object, X, and the angle of projection, </>, two 
 being known, to determine the third. 
 
 1st. To determine the angle of projection, <p. — Make 
 y=0 in equation (22), and solve it with reference to 
 
416 SCIENCE OF GUNNERY. TRAJECTORY IN AIR. 
 
 tan. $ we have, 
 
 tan. <b=l—B. 
 2 V 2 
 
 JEJxample. — Find the angle of projection necessary to throw a 
 
 12-pdr. shot 1800 feet, with an initial velocity of 1500 feet. We 
 
 x 1800 V 1500 „ 
 
 have F=1500 feet; - = ——=0.5336; — =—— = 1.054. From 
 ' c 3370 ' r 1427 
 
 32 17 1800 
 Table (l), .#=1.449; tan. </>=-——. == 1.449. = 0.01864. <j> = 
 
 Z loUO 
 
 1° 05'. 
 
 2d. To determine the initial velocity, V, make y=0, 
 in equation (22), solve it with reference to V, and mul- 
 tiply both members by -, we have. 
 
 )/~B~ t V 2 tan.0~~2* 
 
 X 
 
 Having the values of — and q, seek in table (5) for 
 
 G 
 
 X V 
 
 the value of — , the value of — , which gives that of q ; 
 c r 
 
 multiply — by 1427 and we shall have V. 
 r 
 
 Example.— Find the initial velocity of a 12-pounder shot which, 
 fired under an angle of 1° 05', has a range of 1800 feet. 
 
 1 / 16.08 x 
 
 427 y 0.0181 
 
 1800 
 
 :0.8732. 
 
 1427 V 0.01864 
 
 — = 1.05. F=1.05 x 1427=1498.35 feet. 
 r 
 
 3d. To determine the range, X. — Make y=0 in equa- 
 tion (22), obtain the value of X, and divide both mem- 
 bers of the equation by g, we have, 
 
 X-n tan.* V 2 
 — Jj— —p. 
 
 g c\g 
 
FIRST CLASS. 417 
 
 Having the initial velocity, FJ and angle of projec- 
 tion, 0, we can determine, — and p; seek in table (4), 
 
 V X 
 
 for the value of — , that of — , which gives p; having 
 y c 
 
 X 
 
 _, multiply it by <?, and we have X. 
 
 c 
 
 Example. — Find the range of a 12-pdr. ball, fired under an angle of 
 
 1° 05', with an initial velocity of 1500 feet. 
 
 V 
 c=3370; _ _=1.0511; tan. </>= 0.0 1864. 
 r 
 
 0.01864 1500 rt „„. , £ . . . ., X KO , A v co . A 
 
 Vx= . = 0.774; (from table 4), — = .5340; X— .5340 
 
 3370 16.08 v ! c 
 
 X 3370=1800 feet. 
 
 The slight discrepancies in the three preceding results, arise from 
 
 the neglected decimals. 
 
 In firing spherical case-shot, it is important not only 
 to know the time of flight, in order to regulate the fuze, 
 but it is important to know that the projectile will have 
 sufficient remaining velocity to render the impact of the 
 contained projectiles effective. 
 
 4th. The time of flight can be obtained from equa- 
 
 tion (24), or, t= -=jd). Knowing — and — , we can ob- 
 tain the corresponding value of D from table (3). 
 
 Example. — Find the time of flight of a 12-pdr. spherical case-shot 
 for a distance of 1500 yards, the initial velocity being 1500 feet. 
 
 *^f<» 1.335 J Z = 1 ^° = 1.051 J i> = 1.859. 
 c 3370 r 1427 
 
 *=1^ ) 1.859=5.58 seconds. 
 1500 
 
 5th. The remaining velocity can be obtained from 
 
 27 
 
418 SCIENCE OF GUNNERY. TRAJECTORY IN AIR. 
 
 equation (25), or, v—--. Knowing — and — , obtain 
 ± \ /•> jj c r 
 
 from table (3) the corresponding value of U. 
 
 Example — Find the remaining velocity of a 12-pdr. spherical case- 
 shot at the distance of 1500 yards, the initial velocity being 1500 feet. 
 
 *,!!??_l.a27; .t^J.051; ^=2.882; ,-**» =520 feet. 
 c 3370 r ' 2.882 
 
 This velocity is more than sufficient for a musket-bullet to disable an 
 
 animate object at the distance of 1500 yds. 
 
 423. 2<i cia§s. For angles of projection not exceed- 
 ing 10° or 15°, as in the ricochet fire of guns, howitzers, 
 and mortars. 
 
 The formulas are : 
 
 g x 
 
 y=fl? tan.*-| T ^ ? - A (26) 
 
 X 
 
 tan^tan^-^W-Z ( 27 > 
 
 *= *,* A (28) 
 
 V cos.0 v 7 
 
 •=-5=£ (29) 
 
 (Tcos.0 
 
 If the object be on a level with the piece, the solu- 
 tion of this class of problems is the same as those of 
 class 1st, when the angle is very small ; if not, it will 
 be necessary to substitute for V, V / = F^cos. </>, and after 
 having obtained V n divide it by the cos. 0, which 
 gives V. 
 
 The object being situated at the distance a from the 
 piece, and at the distance b above the horizontal plane 
 passing through the centre of the muzzle, is seen under 
 
 an angle of elevation e, for which tan.e=-. One of the 
 
SECOND CLASS. 419 
 
 two things, the initial velocity or angle of projection 
 being known, to determine the other. 
 
 1st. To determine the initial velocity, V. Substitute 
 in equation (26) the co-ordinates a and b, and V n ' solve 
 
 it with reference to V J / substitute tan. e for -, and di- 
 
 a 
 
 vide both members by r, we have, 
 V 1 / f* 
 
 VB ry tan.(/> — tan.e q ' 
 Having the value of q, seek in table (5) for the known 
 
 value of -, the value of — i corresponding to it, and mul- 
 tiplying by , we shall have V. 
 
 COS.0 
 
 Example. — Find the initial velocity of an 8-inch siege-howitzer shell, 
 which, being fired under an angle of 12°, will strike an object situated 
 1,000 feet from, and 20 feet above, the muzzle of the piece. 
 
 20 
 Tan.0=O.2125; tan.e= — —=0.0200; tan.</>— tan.e=0.1925 ; 
 
 coa.0-0.9781; i_"™ 0.2801; f -JL , /™Z?JW^ 
 c 3570 * 1427 Y .1925 
 
 V _ 0.2150. 1427 „ no . . 
 0.2023; —^ = 0.2150; V== — -— — =313 feet. 
 
 2d. To determine the angle of projection. The result 
 will be sufficiently near the truth, if we substitute, in 
 equation (26), Ffor V n or V cos. ; and solving it with 
 reference to tan. 0, we have, 
 
 tan.0=tan. e+ *L= B, 
 
 in which we substitute for B its value, corresponding 
 to _ and — , obtained from table (1). 
 
420 SCIENCE OF GUNNERY. TRAJECTORY IN AIR. 
 
 Example. — What angle of projection is necessary for an 8-inch 
 siege-howitzer shell to strike an object situated 1000 feet from, and 
 20 feet above, the muzzle ? The initial velocity being 313 feet, 
 
 a 1000 V 313 20 
 
 F=313 feet; -=-—=0.2801; -=-—— = 0.2193; tan.e= — — 
 ' c 3570 ' r 1427 1000 
 
 16.08.1000 
 
 = 0.0200; tan. 0=0.0200+ —-= 1,142 = 0.2084; 0=11° 28 . 
 
 313 2 
 
 424. 3d cia§§. Properties of trajectories under high 
 angles of projection. 
 
 As a projectile rises in the ascending branch of its 
 trajectory, its velocity is diminished by the retarding 
 effect of the air and the force of gravity : in consequence 
 of the resistance of the air alone, the velocity continues 
 to diminish to a point a little beyond the summit of 
 the trajectory, where it is a minimum ; and from this 
 point it increases, as it descends, under the influence of 
 the force of gravity, until it becomes uniform, which 
 event depends on the diameter and weight of the pro- 
 jectile and the density of the air, or, in other words, 
 upon the value of c. 
 
 The inclination of the trajectory decreases from the 
 origin to the summit, where it is nothing ; it increases 
 in the descending branch from the summit to its ter- 
 mination, and if the ground did not interpose an ob- 
 stacle, it would become vertical at an infinite distance. 
 An element of the trajectory in the descending branch 
 has a greater inclination than the corresponding element 
 of the ascending branch. 
 
 Strictly speaking, the trajectory in air is an expoten- 
 tial curve with two asymptotes; the first is the axis of 
 the piece, which is tangent to the trajectory when the 
 initial velocity is infinite ; the second is the vertical line 
 toward which the trajectory approaches as the horizon- 
 
THIED CLASS. 
 
 421 
 
 tal component of the velocity diminishes, and the effect 
 of the force of gravity increases. 
 
 The curvature of the trajectory increases in the as- 
 cending branch, to a point a little beyond the summit. 
 The point of greatest curvature is situated nearer the 
 summit than the point of minimum velocity. 
 
 In the fire of mortar shells under great angles of pro- 
 jection, and at customary distances, the trajectory may 
 be considered as an arc, in which the angle of fall is 
 slightly greater than the angle of projection. In the 
 ascending branch, the arc commences under an angle of 
 0, and terminates under an angle of ; the ratio of the 
 length of this arc to its projection, or a, is calculated 
 for all arcs from 5° to 75°, and arranged, in groups of 
 fives in the accompanying table. 
 
 The value of a is considered the same in the descend- 
 ing as in the ascending branch. 
 
 ARCS. 
 
 a 
 
 ARCS. 
 
 a 
 
 ARCS. 
 
 a 
 
 5° 
 
 1.00127 
 
 30° 
 
 1.05306 
 
 55° 
 
 1.27583 
 
 10 
 
 1.00516 
 
 35 
 
 1.07596 
 
 60 
 
 1.38017 
 
 15 
 
 1.01184 
 
 40 
 
 1.10730 
 
 65 
 
 1.53433 
 
 20 
 
 1.02*165 
 
 45 
 
 1.14777 
 
 70 
 
 1.77772 
 
 25 
 
 1.03514 
 
 50 
 
 1.20189 
 
 75 
 
 2.20349 
 
 The multipliers, B, I, D, and the divisor, U, are cal- 
 culated for the values — and -. and they are em- 
 
 c r ' J 
 
 ployed in equations (26), (27), (28), (29), as in the 
 preceding class of cases. 
 
 1st. Find the initial velocity of a mortar shell, know- 
 ing the range and angle of projection. 
 
 We know — , and by solving equation (26) as before, 
 c 
 
422 SCIENCE OF GUNNERY. TRAJECTORY IN AIR. 
 
 we have. 
 
 r r V tan.<£ * 
 
 Having determined the value of q, seek in table 
 (5) the value of — 'corresponding to it for — ; then 
 
 V C 
 
 multiply it by , and we have V. 
 
 r J J a COS.0 7 
 
 Example. — What initial velocity is necessary to project a 10-inch 
 shell 1,800 feet, under an angle of 45°? 
 
 For a 10-inch shell, cr=r4677; for 45°, a = 1.148; — = 
 
 c 
 
 1.148.1800 1.148 
 
 = 0.4418; q 
 
 4677 ' * 1427 
 
 / 16.08. 1800 „ 10 ^ ., A 
 \ / , nnnn —0.1369. By th( 
 
 y l.oooo : 
 
 aV 
 aid of table (5) we find ^^0.1490 ; and from this we get 
 
 Tr 0.1490.1427 nn m A 
 v = , , ,» „*«», = 2 62 feet. 
 1.148.0.7071 
 
 2d. To determine the angle and velocity of fall, and 
 the time of flight, knowing the initial velocity and range. 
 Let the projectile be the same as in the preceding case. 
 
 Example. — We have — =0.4418 ; and ^ = 0.1490 ; from ta- 
 ble (1) we have /= 1.291 ; from table (2), D = 1.121 ; and £7=1.272. 
 Substituting the proper values in equation (25) we have 
 
 oo 1 *1 1 800 
 
 Tan. 0= 1.0000- 262<a707i)2 . 1.280= —1.159; 6= — 49° 12'. 
 
 The negative sign indicates that the angle of fall is measured in an 
 opposite direction from the angle of projection. Making the proper 
 substitutions in equations (28) and (29), we have 
 
 1800 .1.127=10.95". v =m^== 222 feet 
 
 262.0.7071 1.272.0.6534 
 
 3d. To determine the range, knowing the initial ve- 
 locity and angle of projection. 
 
TRAJECTORY OF OBLONG PROJECTILE. 423 
 
 • 
 
 aV 
 
 We have a, and — -'; make y=o in equation (26) ; 
 solve it with reference to X, and multiply both mem- 
 bers by — - , and we have, 
 
 aX jy a V . n 
 
 — B— sm. 2w>=/?. 
 
 c gc 
 
 X V 
 
 Having found the value of c - , which for - - gives 
 
 c i 
 
 p (table 4) ; multiply it by—, and we have X. 
 
 Example. — Find the range of a 10-inch mortar shell, the angle of 
 projection of which is 45°, and the initial velocity is 262 feet. 
 
 aV. 
 
 Cos. = 0. 7071 ; the sin. 20 = 1.0000; and a— 1.148; — == 
 
 2 
 
 1.148.262.0.7071 aVi . j 1.148.262 , _^ 
 
 = 0.1490 ; p= — sin.2 = — » • „. 1.0000 = 
 
 1427 ' l gc Y 32.17.4677 
 
 0.5238 from table (4) --=0.4412 ; X= — =1798 feet. 
 
 v c ' 1.148 
 
 The slight discrepancies in these, as in the preceding 
 results, arise from the neglected decimals. 
 
 425. Comparison of true and calculated trajectories. 
 
 In consequence of considering the inclination of the tra- 
 jectory as constant in the preceding equations, the re- 
 sistance of the air is slightly underestimated in the 
 more inclined portions of the trajectory, or at the be- 
 ginning and end, and slightly overestimated in the less 
 inclined portions, or about the summit. It follows that 
 the calculated trajectory will at first rise above the true 
 one, then pass below it, and again pass above it ; the 
 calculated ranges will therefore be found slightly in 
 excess. 
 
 426. Trajectory of oblong projectile. From the law 
 
424 SCIENCE OF GUNNERY. DEVIATION OF PROJECTILES. 
 
 of inertia, a rifle projectile moves through the air with 
 its axis of rotation parallel to the axis of the bore. 
 Hence, it follows, that an oblong projectile, fired under 
 a low angle of projection, presents a greater surface to- 
 ward the earth, and less parallel to it, than a round 
 projectile of the same weight ; consequently the vertical 
 component of the resistance of the air is greater, and 
 the horizontal component less, in the first case than in 
 the second. The effect of this will be to give an oblong 
 projectile a flatter trajectory and longer range than a 
 round one. 
 
 DEVIATION OF PROJECTILES. 
 
 427. Nature and cau§e§. The path described by the 
 centre of inertia of a projectile, moving under the influ- 
 ence of gravity and the tangential resistance of the air, 
 is called the normal trajectory / and it is this trajectory 
 which has been the subject of the preceding discussions. 
 In practice, various causes are constantly at work to 
 deflect a projectile from its normal path, and it becomes 
 necessary to study the nature of these causes, and their 
 effects. 
 
 All deviating causes may be divided into two classes 
 — those which act while the projectile is in the bore of 
 the piece, and those which act after the projectile has 
 left it. The first class includes all the causes which 
 affect the initial velocity, and give rotation to the pro- 
 jectile ; the second includes the action of the air. 
 
 428. Causes which affect initial velocity. The princi- 
 pal causes which affect initial velocity are variations in 
 the weights of the powder and projectile, the manner 
 
ROTATION. 425 
 
 of loading, the temperature of the piece, and the ballot- 
 ing of the projectile along the bore. Experiments made 
 by firing siege and field projectiles into the ballistic pen- 
 dulum, show that, with care, the mean variation in the 
 initial velocity, in a series of fires, doe3 not exceed 20 feet. 
 
 A variation of 20 feet in initial velocity only produ- 
 ces a variation of £ a foot, in the vertical height of the 
 trajectory of a 12-pdr. ball, at a distance of 1,000 yards. 
 
 429. Rotation. The principal cause of the deviation 
 of a projectile is its rotation combined with the resist- 
 ance of the air. It is proposed, in the first place, to 
 show how rotation may be produced, and, in the sec- 
 ond, to show how rotation, combined with the resist- 
 ance of the air, produces deviation. 
 
 By balloting. If the projectile be spherical and ho- 
 mogeneous, rotation is produced by the bounding or 
 balloting of the ball in the bore, arising from the wind- 
 age. In this case the axis of rotation is horizontal, and 
 passes through the centre of the ball ; the direction 
 of rotation depends on the side of the projectile which 
 strikes the surface of the bore last ; if it strike on the 
 upper side, the front surface of the projectile will move 
 upward; if on the lower side, this surface will move 
 downward. 
 
 The velocity of rotation from this cause depends on 
 the windage, or depth of the indentations in the bore, 
 the charge being the same. It has been found to be, 
 for ordinary windage, about 30 feet for a 24-pdr. shell 
 fired with 2f lbs of powder. 
 
 By eccentricity. If, from the structure of the ball, 
 or from some defect of manufacture, the centre of grav- 
 ity do not coincide with the centre of figure, rotation 
 
426 SCIENCE OF GUNNERY. DEVIATION OF PROJECTILES. 
 
 generally takes place around the centre of gravity. 
 This arises from the fact that the resultant of the 
 charge acts at the centre of figure, while inertia, or re- 
 sistance to motion, acts at the centre of gravity. The 
 axis of rotation passes through the centre of gravity, 
 and is perpendicular to a plane containing the resultant 
 of the charge and the centres of figure and gravity. For 
 the same charge, the velocity of rotation is proportional 
 to the lever arm, or perpendicular, let fall from the cen- 
 tre of gravity to the resultant of the charge. 
 
 Knowing the position of the centre of gravity of the 
 ball in the bore, it is easy to foretell the direction and 
 velocity of rotation. In general terms, the front surface 
 of the projectile moves toward the side of the bore on 
 which the centre of gravity is situated, and the velocity 
 of rotation is greatest when the line joining the centres 
 of gravity and figure is perpendicular to the axis of 
 the bore. 
 
 The position of the centre of gravity of a projectile 
 is found by floating in a mercury bath ; and by an in- 
 strument called the eccentrometer. The topmost point 
 of the surface, when the projectile has settled to a state 
 of rest in the bath, marks one point at which the line 
 joining the centre of gravity and figure pierces the sur- 
 face ; the position of the centre of gravity along this 
 line is determined by the eccentrometer, which is a pe- 
 culiar kind of balance. w being the weight of the 
 projectile, and x the distance of its centre of gravity 
 from the fulcrum of the balance, and w being the weight 
 necessary to balance the projectile, and a its distance 
 from the fulcrum, we have, from the equality of the 
 moments— 
 
THE EFFECT OF KOTATION. 427 
 
 . aw 
 aw =zw%. or x=. 
 
 w 
 
 The position of the projectile on the balance being 
 known, by placing the marked point on the surface 
 nearest the fulcrum, the position of the centre of grav- 
 ity becomes known; for if b be the distance of the 
 marked point from the fulcrum, and r the radius of the 
 projectile, x—b—r is the distance between the centres 
 of gravity and figure. 
 
 430. The effect of rotation. The effect of rotation in 
 producing deviation, may be studied under three heads: 
 1st. When the projectile is spherical and concentric. 
 2d. When it is spherical and eccentric; and 3d. When 
 it is oblong. 
 
 Concentric projectiles. The simplest case is that of a 
 homogeneous spherical projectile, rotating around a ver- 
 tical axis passing through the centre of gravity. 
 
 Let A B D represent the great circle cut out of 
 the sphere perpendicular to the axis of rotation, and 
 suppose rotation to take place 
 in the direction A C B, and the 
 motion of translation in the di- 
 rection A B ; it is evident that 
 each point of the circle moves 
 in the direction A B, with a ve- Fig. iSS! 
 
 locity which is equal to the velocity of translation, plus 
 or minus the component of its velocity of rotation in 
 the direction of the axis A B, which is equal to the 
 projection of the arc over which the point moves in a 
 unit of time, on the line A B. The points <7and D 
 have the greatest velocity in the direction of this line, 
 A B, and the points A and B the least. All the points 
 
428 SCIENCE OF GUNNERY. DEVIATION OF PROJECTILES. 
 
 in the semi-circle A C B rotate in a forward direction, 
 and the components of their velocities of rotation must 
 be added to that of translation ; while the points in the 
 semicircle B D A move backward in rotation, and the 
 components of their velocities must be subtracted from 
 it. A body moving in the air draws with it a film of 
 the particles which surround it, and these particles set 
 in motion the adjacent particles, and so on from one 
 layer to another ; the number of particles set in motion 
 and their reaction on the surface of the projectile, de- 
 pend on the velocity of the moving surface; now it has 
 been shown that the surface A O B moves with a 
 greater velocity than the opposite side, the reaction, or 
 pressure upon it, must be greater than upon the latter, 
 and the projectile will be urged in the direction C D. 
 Eccentric projectiles. Let A G B D represent the 
 great circle cut out of an eccen- 
 tric projectile perpendicular to 
 the axis of rotation, and contain- 
 ing the centre of figure O, and 
 the centre of gravity O'. Sup- 
 pose the motions of rotation and 
 Fi s- 139 - translation to take place as in 
 
 the preceding case, it follows that the same cause will 
 operate in this, as in the preceding case, to deviate the 
 projectile in the direction CD; but there is another 
 and more powerful cause operating to deviate the pro- 
 jectile in the same direction, and that is, the greater 
 pressure on the side A C B arising from the greater 
 surface offered to the air in consequence of the eccen- 
 tricity. 
 
 Prof. Magnus 1 apparatus. These phenomena may be 
 
THE EFFECT OF ROTATION. 429 
 
 easily illustrated by the very simple and ingenious ap- 
 paratus devised by Prof. Magnus, of Berlin. Let C 
 (fig. 140) represent a light brass cylinder, delicately 
 susj>ended in a ring, and made to revolve rapidly 
 
 around its vertical axis, by 
 
 means of a string, after the man- 
 
 ner of a top ; let this ring be 
 
 suspended at the extremity of 
 
 a wooden lever I>\ which, in 
 
 turn, is suspended by a delicate 
 
 wire from the ceiling, so that it 
 
 may rotate freely in a horizontal direction ; let Pbea 
 
 counterpoise, and R the direction of a strong current 
 
 of air blowing upon the cylinder from a fan-blower. 
 
 It is invariably found, that the axis of the cylinder 
 will move in the opposite direction from the side which 
 is moving toward the current of air from the blower 
 (see direction of the arrows) ; but if there be no rota- 
 tion of the cylinder, the axis will remain stationary. 
 
 Conclusions. If a projectile be spherical and concen- 
 tric, rotation takes place from contact with the surface 
 of the bore around a horizontal axis, and the effect will 
 be to shorten or lengthen the range, as the motion of 
 the front surface is downward or upward. 
 
 If the projectile be eccentric, the motion of the front 
 surface is generally toward the side on which the 
 centre of gravity is situated, and the deviation takes 
 place in this direction. 
 
 The extent of the deviation for the same charge, de- 
 pends on the position of the centre of gravity; the 
 horizontal deviation being the greatest when the centres 
 of gravity and figure are in a horizontal plane, and the 
 
430 SCIENCE OF GUNNERY. DEVIATION OF PROJECTILES. 
 
 line which joins them is at right angles to the axis of 
 the piece ; the vertical deviation will be the greatest 
 when these centres are in a vertical plane, and the line 
 which joins them is at right angles to the axis of the 
 piece. If the axis of rotation coincide with the tangent 
 to the trajectory throughout the flight, all points of the 
 surface have the same velocity in the direction of the 
 motion of translation, and there will be no deviation. 
 This explains why it is that a rifle-projectile moves 
 through the air more accurately than a projectile from 
 a smooth-bored gun. 
 
 In the experiments of Major Wade with 32-pdr. field- 
 shells, made purposely eccentric, the difference of the 
 extreme lateral deviations, produced by placing the 
 centre of gravity first on one side and then on the other, 
 amounted to 100 yds., or one-fourth of the entire range. 
 
 The experiments of Captain Dahlgren with service 32- 
 pdr. balls, show the following results when the centre 
 of gravity is placed in different positions in the verti- 
 cal plane through the axis of the bore. 
 
 POSITION OF CENTRE OF QRAVITY IN VERTICAL PLANE. 
 
 90° up. 
 
 90° down. 
 
 Inward. 
 
 45° up. and in. 
 
 1415 yds. 
 
 1264 yds. 
 
 1329 yds. 
 
 1360 yds. 
 
 In accurate firing, therefore, it is important to know 
 the true position of the centre of gravity : in ricochet 
 firing over smooth water, the number of grazes may be 
 increased or diminished by placing, in loading, the cen- 
 tre of gravity above or below the centre of figure. 
 
 The first person to call attention to the deviation 
 
DEVIATION OF OBLONG PROJECTILES. 431 
 
 produced by rotation, was Kobins, who illustrated it by 
 bending a musket-barrel to the right, and firing through 
 a succession of paper screens ; the projectile was observed 
 to deviate, first to the right, in the direction in which 
 the muzzle was pointed, and then to the left, in the 
 opposite direction from the side of the projectile which 
 rotates toward the front. 
 
 431. deviation of oblong projectiles. The cause of 
 the deviation of an oblong rifle pro- 
 jectile is quite different from one of 
 spherical form. An oblong projec- 
 tile moving in the air is acted upon 
 Pig. 141. D y two rotary forces, viz. ; one which 
 
 gives it its normal rotary motion around its axis of pro- 
 gression, and another the resistance of the air, which, in 
 consequence of the deflection of the axis of progression 
 from the tangent to the trajectory by the action of grav- 
 ity, does not pass through the centre of inertia, but 
 above or below it, depending on the shape of the pro- 
 jectile. From a law of mechanics, a body thus circum- 
 stanced, will not yield fully to either of the forces that 
 thus act upon it, but its apex will move off with a 
 slow uniform motion to the right or left of the vertical 
 plane, depending on the relative direction of the two 
 rotary forces. If the action of these forces be contin- 
 ued sufficiently long, it will be seen that the axis of the 
 projectile before referred to, describes a cone around a 
 line passing through the centre of inertia and parallel 
 to the direction of the resistance of the air. 
 
 Owing to the short duration of the flight of an ordi- 
 nary projectile, it is only necessary to consider the first 
 part of this conical motion. If the projectile rotates in 
 
432 SCIENCE OF GUNNEKY. DEVIATION OF PEOJECTILES. 
 
 the direction of the hands of a watch to the eye of the 
 marksman, and the resultant of the resistance of the air 
 pass above the centre of inertia, as it does in the service 
 bullet with a conoidal point, see fig. 141, then the point 
 of the projectile will move to the right, which brings 
 the left side of the projectile obliquely in contact with 
 the current of the air. The effect of this position with 
 reference to the air, will be to generate a component 
 force that will urge the projectile to the right of the 
 plane of fire, as a vessel sailing on the wind has a mo- 
 tion to the leeward. 
 
 If the bore be grooved with a left-handed twist, the 
 deviation will be to the left of the plane of fire, as has 
 been shown by actual experiment. This peculiar devi- 
 ation was called by the French officers that first observed 
 it, " derivation" or " drift." That it is not produced by 
 the effect of the recoil on the shoulder of the marksman, 
 1 as some assert, is shown by the fact that drift increases 
 more rapidly than the distance. 
 
 The following table gives the drift at different dis- 
 tances, for the French rifle, model of 1842, with a twist 
 of 4.37 feet, and a bullet with a single groove : 
 
 Distances in 
 yards. 
 
 218 
 
 328 
 
 437 
 
 546 
 
 656 
 
 165 
 
 874 
 
 984 
 
 1093 
 
 1312 
 
 1421 
 
 Drift in feet 
 and inches. 
 
 .5" 
 
 l'.l" 
 
 1'.9" 
 
 1 
 2'.0"U'.9" 
 
 7'.6" 
 
 11'.6" 
 
 16'.1" 
 
 21'.0" 
 
 38'.4" 
 
 50'.6" 
 
 In consequence of the reduced calibre and twist, the 
 drift of our present rifle-musket projectiles is less than 
 the foregoing. The mean drift of 40 shots fired from 
 two service rifle-muskets, at a distance of 1,150 yds., in 
 
SUMMARY OF DEVIATING CAUSES. 433 
 
 a perfectly calm day, was about 18 feet; not a single 
 shot deviated to the left of the point aimed at.* 
 
 432. Effect of wind. The deviating effect of wind 
 depends on its force, and its direction with regard to 
 the plane of fire ; generally speaking, large and heavy 
 projectiles, moving with high velocities, are deviated 
 less than those of contrary character. It is difficult to 
 calculate the effect of the wind in any particular case ; 
 in making allowance for it, therefore, the gunner should 
 be guided by experience and judgment. For the same 
 projectile, velocity, and wind, the deviation varies nearly 
 as the square of the range. 
 
 433. Summary of deviating causes. The following 
 summary may be considered as embracing nearly all the 
 causes of deviation of cannon and small-arm projectiles. 
 
 1st. From the construction of the piece. These causes 
 are, wrong position of the sight ; bore not of the true 
 size; crooked barrel; too hard on the trigger; wind- 
 age ; the recoil ; and spring of the barrel. 
 
 2d. From the charge of powder. Improper weight; 
 form of grain and variable quality of the powder ; in- 
 jury from dampness; more or less ramming; sticking 
 along the bore from foulness and dampness. 
 
 3d. From the projectile. Not of the exact size, shape, 
 or weight ; disfiguration in loading, or on leaving the 
 bore; eccentricity. 
 
 4th. From the atmosphere, &c. The effect of wind ; 
 variations in the temperature, moisture, and density of 
 
 * The subject of drift has been fully exposed in a learned analytical investigation by 
 General Barnard, of the engineer corps, who shows that it is a particular case of the 
 gyroscope. It has also been explained experimentally by Professor Magnus, of Berlin, 
 a copy of whose apparatus may be found in the Museum of the United States Mili- 
 tary Academy. 
 
 28 
 
434 SCIENCE OF GUNNERY. DEVIATION OF PROJECTILES. 
 
 the air; position of the sun as regards the effect on 
 the aim; difference of level between the object and 
 piece ; and rotation of the earth. 
 
 The latter source of deviation arises, 1st. From the 
 fact that all points on the surface of the earth, not in 
 the same parallel of latitude, move with different angu- 
 lar velocities; and 2d. That when a body is thrown 
 from one point to another, it carries with it the angu- 
 lar velocity with which it started. Applying these 
 facts, it is found that a projectile will deviate to the 
 right of the object, whatever may be the direction of 
 the line of fire, and at a distance from it, depending on 
 the latitude of the place, and on the time of flight and 
 the range of the projectile. 
 
 Poisson has shown that a 12-inch shell weighing 
 200 lbs., fired under an angle of 45°, with an initial 
 velocity of 900 feet, will deviate from 15 to 20 feet to 
 the right of the object — the range being about 4,400 
 yards. 
 
USE OF PROJECTILES NOT SUITED TO THE BORE. 435 
 
 CHAPTER IX. 
 
 LOADING, POINTING, AND DISCHARGING FIRE- 
 ARMS. 
 
 434. Loading. In loading guns and howitzers, the 
 powder is carefully put up in a cartridge-bag of woollen 
 cloth, which is either attached to, or carried separate 
 from the projectile, depending on the weight of the 
 projectile. In ramming a charge, only a sufficient force 
 should be used to send it home, as the space which the 
 powder occupies affects the initial velocity. In loading 
 mortars, the powder is poured from the cartridge-bag 
 into the chamber, and levelled with the hand ; the shell 
 is then carefully lowered upon it with the hooks. 
 
 435. Precautions. After a piece has been discharged 
 the bore should be well sponged, to extinguish any 
 burning fragments of the cartridge that may remain ; 
 and to prevent the current of air from fanning any 
 burning fragments that may collect in the vent, it 
 should be kept firmly closed with a thumb-stall in the 
 operation of sponging. Experience shows that the use 
 of a wet sponge is dangerous, as it contributes to form, 
 from the fragments of the cartridge-bag, a substance 
 which retains fire. 
 
 436. Use of projectiles not suited to the bore. It may 
 be sometimes necessary to fire projectiles that are either 
 very much smaller or larger than the bore. 
 
 If it be desired to use a gun-shell, or solid shot, which 
 
436 LOADING AND POINTING FIKE-AKMS. 
 
 is much smaller than the bore, it is strapped to a stout 
 sabot which fits the bore ; if a mortar-shell, it is placed 
 in the centre of the bore by means of wedges, and the 
 surrounding space is filled up with earth. 
 
 Mortar-shells are fired from guns and howitzers, by 
 digging a hole in the ground about 20 inches deep, and 
 placing in it two pieces of stout plank inclined at an 
 angle of 45°, for the support of the breech ; the chase 
 is supported on a movable wedge, which rests on skids 
 firmly secured with platform stakes;* the charge of 
 powder is then inserted in the bore, and the projectile 
 is placed on the muzzle, and secured by passing strings 
 over it, and tying their ends to a rope, which encircles 
 the neck of the chase. 
 
 Pieces fired in this way should be elevated 40° or 
 45°; thus situated, the fuze of the 8-inch mortar-shell 
 takes fire from very small charges ; but the 10-inch fuze 
 should be primed with strands of quick-match, which 
 are allowed to hang over the sides of the shell. 
 
 POINTING. 
 
 To point or aim a fire-arm is, to give it such direction 
 and elevation that the projectile shall strike the object. 
 To do this properly, it is necessary to understand the 
 relations which exist between the line of sight, line of 
 fire, trajectory, &c. 
 
 437. I>eflnition§. The line of sight is the right line 
 containing the guiding points of the sights. The sights 
 are two pieces, A and B, on the upper surface of the 
 
 * Pieces that have been disabled by breaking off a trunnion, may be fired in 
 this manner. 
 
DEFINITIONS. 437 
 
 Fig. 142. 
 
 gun, the situation of which with regard to the axis of 
 the bore is known. The front sight is situated near the 
 muzzle, or on the right rimbase, and is generally fixed ; 
 the rear sight is placed near the breech-sight, and is 
 movable in a vertical, and sometimes in a horizontal di- 
 rection. The natural line of sight is the line of sight 
 nearest the axis of the piece ; the others are called arti- 
 ficial lines of sight. 
 
 The line of fire is the axis of the bore prolonged in 
 the direction of the muzzle, or CD. 
 
 The angle of fire is the angle included between the 
 line of fire and horizon; on account of the balloting 
 of the projectile, the angle of fire is not always equal 
 to the angle of departure, or projection. See section 
 268. 
 
 The angle of sight is the angle included between 
 the line of sight and line of fire ; angles of sight are 
 divided into natural and artificial angles of sight, cor- 
 responding to the natural and artificial lines of sight 
 which enclose them. 
 
 The plane of fire is the vertical plane containing the 
 line of fire. 
 
 The plane of sight is the vertical plane containing the 
 line of sight. 
 
 The point-blank is the point at which the line of sight 
 insersects the trajectory, or P. Strictly speaking, the 
 line of sight intersects the trajectory at two points, C 
 
438 LOADING AND POINTING FIRE-ARMS. 
 
 and P / but, in practice, the j)oint P is only considered. 
 The distance, B P, is called the point-blank distance. 
 
 The natural point-blajik corresponds to the natural 
 line of sight ; all other point-blanks are called artificial 
 point-blanks. In speaking of the point-blank of a 
 piece, the natural line of sight is supposed to be hori- 
 zontal. 
 
 In the British service, the point-blank distance is the 
 distance at which the projectile strikes the level ground 
 on which the carriage stands, the axis of the piece be- 
 ing horizontal. It is evident that this definition of 
 point-blank distance conveys a better idea of the power 
 of the piece than the former, which makes it depend on 
 the form of the piece, as well as on the charge. 
 
 As the angle of sight A C C is increased, the point- 
 blank distance is increased ; as it is diminished, the in- 
 tersections of the line of sight and trajectory approach 
 each other until they unite, when the line of sight and 
 trajectory are tangent to each other ; beyond this, the 
 point-blank is imaginaiy. 
 
 As the angle of fire increases, the force of gravity 
 acts more in opposition to the force of projection, and 
 the point-blank distance is diminished, until at 90° it 
 becomes zero. Under an angle of depression, the force 
 of gravity acts more nearly in the direction of gravity, 
 and the point-blank distance is increased, becoming in- 
 finite when the angle of depression is equal to 90° minus 
 the angle of sight. 
 
 In ordinary firing, it is not considered that the trajec- 
 tory changes its position with reference to the lines of 
 sight and fire, for angles of elevation and depression, 
 less than 15°. In aiming at an object, therefore, the 
 
POINTING GUNS AND HOWITZERS. 439 
 
 angle of elevation of which is less than 15°, aim as though 
 it were in the same horizontal plane with the piece. 
 
 For the same piece, the point-blank distance in- 
 creases with the charge of powder; for the same 
 initial velocity, a large projectile has a greater point- 
 blank distance than a small one ; a solid shot than a 
 hollow one ; an oblong projectile than a round one ; or, 
 in other words, it varies with the value of c, before re- 
 ferred to. 
 
 Range is the distance at which a projectile first 
 strikes the ground on which the carriage is situated ; 
 extreme range is the, distance to the point at which the 
 projectile is brought to a state of rest. 
 ; 438. Pointing guns and howitzers. In pointing 
 2- «* guns and howitzers under ordinary angles of elevation, 
 &*•»• the piece is first directed toward the object, and then 
 elevated to suit the distance. The accuracy of the aim 
 depends — 1st. On the fact that the object is situated in 
 the plane of sight; 2d. That the projectile moves in 
 the plane of fire, and that the planes of sight and fire 
 coincide, or are parallel and near to each other; and 
 3d. On the accuracy of the elevation. 
 
 The first of these conditions depends on the eye of 
 the gunner, and the accuracy and delicacy of the sights ; 
 the errors under this head are of but little practical im- 
 portance. 
 
 When the trunnions of the piece are horizontal, and 
 the sights are properly placed on the surface of the 
 piece, the planes of sight and fire will coincide; but 
 when the axis of the trunnions is inclined, and the 
 natural line of sight is oblique to the axis of the bore, 
 the planes are neither parallel nor coincident, and the 
 
^4 
 
 440 LOADING AND POINTING FIRE-ARMS. 
 
 aim will be incorrect. If the natural line of sight be 
 made parallel to the line of fire, by making the height 
 of the front sight equal to the dispart of the piece, the 
 planes of sight and fire will be parallel, and at a dis- 
 tance from each other equal to the radius of the breech 
 multiplied by the sine of the angle which the axletree 
 makes with the horizon. To show this, let the circle 
 A C B D represent the section of the breech of the 
 piece taken at right angles to the axis, 
 and C the projection of the natural 
 line of sight upon this plane; let A' 
 B' be the inclined position of the 
 axletree, or trunnions, C marks the 
 revolved position of the natural line 
 Fig - 143 ' of sight, and C D' the trace of the 
 
 plane of sight, which is parallel to C Z>, the trace of the 
 plane of fire. As the lines of sight and fire are paral- 
 lel in their revolved position, the planes of sight and 
 fire must also be parallel. The angle COC' = BOB\ 
 therefore CC'= OC' sin. BOB', It is easily seen that 
 with this arrangement of the front sight, the error of 
 pointing can never exceed the radius of the breech. 
 By an inspection of the figure, it will also be seen, that 
 in the revolved position of the line of sight, the eleva- 
 tion is diminished by a small quantity, which is equal 
 to the versed sine of the arc CO. 
 
 By referring to the construction of the pendulum 
 hausse, on page 255, we see that if its centre of motion 
 coincide with the point C\ and the scale coincide with 
 the line C JD', the error of aiming with an artificial 
 line of sight is practically no greater than with the 
 natural line of sight. 
 
POINTING GUNS AND HOWITZERS. 441 
 
 If the natural line of sight be not parallel to the 
 axis of the piece, the planes of sight and fire intersect 
 at a short distance from the muzzle ; hence, it follows, 
 that as the object is situated in the plane of sight, the 
 projectile will deviate from the object to the side on 
 which the lower wheel is situated, and at a distance 
 from it, which is proportional to the distance of the 
 object from the piece; to correct for this source of 
 error, the line of sight should be pointed to the side 
 of the higher wheel, and at a distance from the object, 
 which is proportional to the distance of the object 
 from the piece. 
 
 Siege and sea-coast cannon are generally fired from 
 fixed platforms, which renders the axis of the trunnions 
 horizontal ; they are, therefore, not furnished with pen- 
 dulum sights. 
 
 In case the axis of the trunnions is not horizontal, 
 and the piece has not a pendulum hausse, the highest 
 points of metal at the breech and muzzle may be de- 
 termined by the gunner's level (see page 254), and 
 marked with chalk ; the centre line of the tangent 
 scale, or breech-sight, is placed on the mark at the 
 breech, the slider is placed at the proper elevation, and 
 the aim is taken along the notch of the slider and the 
 mark on the muzzle. This method, however, does not 
 give a perfectly accurate aim. 
 
 In the absence of a breech-sight, the piece can be 
 pointed with the natural line of sight so as to strike 
 objects not situated at point-blank distance; if the 
 object be within point-blank range, as at P" (fig. 
 142), the natural line of sight should be depressed be- 
 low the object as much as the trajectory is above it ; if 
 
442 LOADING AND POINTING FIRE-ARMS. 
 
 it be beyond point-blank, as at P\ the natural line of 
 sight should be directed to a point JI, which is as much 
 above the object, as the point H\ of the trajectory, is 
 below it. 
 
 Owing to the shape and size of the reinforce of sea- 
 coast cannon, the natural line of sight is formed by 
 affixing a front sight to the muzzle, or to a projection 
 cast on the piece between the trunnions. Although 
 the latter arrangement does not give quite so long a 
 distance between the sights as is desirable, it permits 
 the use of a shorter breech-sight, and the front sight 
 does not interfere with the roof of the embrasure, when 
 the piece is fired under high elevation. 
 
 439. Pointing mortars and small-arm§. In pointing 
 small-arms and mortars, the piece is first given the ele- 
 vation, and then the direction necessary to attain the 
 object. 
 
 Pointing mortars. Mortars are generally fired from 
 behind epaulements, which screen the object from the 
 eye of the gunner. 
 
 The elevation is first given by a gunner's quadrant, 
 applied as described on page 256 ; and the direction is 
 given by moving the mortar-bed with a handspike, so as 
 to bring the line of sight into the plane of sight, which, 
 by construction, passes through the object and the cen- 
 tre of the platform. The plane of sight may be deter- 
 mined in several ways; the method prescribed is to 
 plant two stakes, one on the crest of the epaulement, and 
 the other a little in advance of the first, so that the two 
 shall be in a line with the object, and the gunner stand- 
 ing in the middle of the rear-edge of the platform ; a 
 cord is attached to the second stake, and held so as to 
 
POINTING MORTARS AND SMALL-ARMS. 443 
 
 touch the first stake ; a third stake is driven in a line 
 with the cord, in rear of the platform, and a plummet 
 is attached to this cord so as to fall a little in rear of 
 the mortar. It is evident that the cord and plummet 
 determine the required plane of sight into which the 
 line of sight of the mortar must be brought. 
 
 The usual angle of fire of mortars is 45°, which cor- 
 responds nearly with the maximum range. The advan- 
 tages of the angle of greatest range are : 1st. Economy 
 of powder; 2d. Diminished recoil, and strain on the 
 piece, bed, and platform ; 3d. More uniform ranges. 
 
 When the distance is not great, and the object is to 
 penetrate the roofs of magazines, buildings, <fcc., the 
 force of fall may be increased by firing under an angle 
 of 60°. The ranges obtained under an angle of 60° are 
 about one-tenth less than those obtained with an angle 
 of 45°. 
 
 If the object be to produce effect by the bursting of 
 the projectile, the penetration should be diminished by 
 firing under an angle of 30°. 
 
 When the object is not on a level with the piece, the 
 angle of greatest range is considered in practice to be 
 45°+|-0, or 45 — ^-0, being the angle of elevation or 
 depression of the object. Thus to attain a magazine, 
 for instance, situated' on a hill, for which 0=15°, the 
 angle of greatest range is 52|-° instead of 45°. 
 
 The angle of fire being fixed at 45° for objects on the 
 same level with the piece, the range is varied by vary- 
 ing the charge of powder. The practical rule is founded 
 on the knowledge of the amount of powder necessary 
 to diminish or increase the range 10 yards. For the 
 French 8 and 10 inch siege-mortars, this amount is 
 
444 LOADING AND POINTING FIRE-ARMS. 
 
 about 60 grains for the former, and 125 grains for the 
 latter. 
 
 A practical rule for finding the time of flight by 
 which the length of the fuze is regulated, is to take the 
 square root of the range in feet, and divide it by four ; 
 the quotient is the approximate time in seconds. 
 
 Stone-mortars are pointed in the same manner as 
 common mortars : the angle of fire for stones is from 
 60° to 75°, in order that they may have great force in 
 falling; the angle for grenades is about 33°, in order 
 that their bursting effect may not be destroyed by their 
 penetration into the earth. 
 
 440. Nigut-flring. Cannon are pointed at night by 
 means of certain marks, or measurements, on the car- 
 riage and platform, which are accurately determined 
 during the day. 
 
 In the case of guns and howitzers, the elevation 
 may be determined by marking the elevating screw 
 where it enters the nut, or by measuring the distance 
 between the head of the screw and stock. In the 
 case of mortars, the position of the quoin may be 
 determined by marking, or by nailing a cleat on the 
 bolster. 
 
 The direction of a carriage or mortar-bed is deter- 
 mined by nailing strips of boards along the platform, 
 as guides to the trail and wheels; to prevent the strips 
 from being injured by the recoil, they should be nailed 
 at a certain distance from the carriage, or bed, and the 
 space filled up with a stick of proper width, which 
 should be removed before firing. The chassis of a sea- 
 coast carriage can be secured in a particular direction 
 by firmly chocking the traverse wheels. 
 
GRADUATION OF REAR-SIGHTS. 445 
 
 440. Pointing smaii-anns. The rear-sights of small- 
 arms are graduated with elevation marks for certain 
 distances, generally every hundred yards; in aiming 
 with these, as with all other arms, it is first necessary to 
 know the distance of the object. This being known, 
 and the slider being placed opposite the mark corre- 
 sponding to this distance, the bottom of the rear-sight 
 notch, and the top of the front sight, are brought into a 
 line joining the object and the eye of the marksman. 
 The term coarse-sight is used when a considerable por- 
 tion of the front-sight is seen above the bottom of the 
 rear-sight notch; and the term fine-sight, when but a 
 small portion of it is seen. The graduation marks being 
 determined for a fine-sight, the effect of a coarse-sight is 
 to increase the true range of the projectile. 
 
 441. Graduation of rear-sigh t§. If the form of the 
 trajectory be known, the rear-sight of a fire-arm can be 
 graduated by calculation; the more accurate and reli- 
 able method, however, is by trial. Suppose it be re- 
 quired to mark the graduation for 100 yards; the slider 
 is placed as near the position of the required mark as 
 the judgment of the experimenter may indicate ; and, 
 with this elevation, the piece is carefully aimed, and 
 fired, say ten times, at a target placed on level ground, 
 at a distance of 100 yards. If the assumed position of 
 the slider be correct, the centre of impact of the ten 
 shot-holes will coincide with the point aimed at ; if it 
 be incorrect, or the centre of impact be found below 
 the point aimed at, then the position of the slider is too 
 low on the scale. Let P be the point aimed at, and P* 
 the centre of impact of the cluster of shot-holes; we 
 have, from close similarity of the triangles, A!F : FP:: 
 
446 LOADING AND POINTING ITRE-AKMS. 
 
 Fig. 144 
 
 A' A" : PP\ from which we can determine A'A r \ the 
 quantity that must be added to AA', to give the cor- 
 rect position of the graduation mark for 100 yards. If 
 the centre of impact had been above i 3 , the trial mark 
 would have been too high. Lay off the distance A A" 
 above A", on the scale, and we obtain an approximate 
 graduation for 200 yards, which should be corrected in 
 the same way as the preceding, and so on. The dis- 
 tance PP' is found by taking the algebraic sum of the 
 distances of all the shots from the point P, and dividing 
 it by the number of shots. It will be readily seen that 
 an approximate form of the trajectory may be obtained 
 by drawing a series of lines through the different grad- 
 uation marks of the rear- sight, and the top of the front- 
 sight, and laying off from the front-sight, on each line, 
 the corresponding range. The points thus determined 
 are situated in the required trajectory. 
 
 442. Distance of object. Various instruments have 
 been devised to determine the distances of objects, based 
 on the measurement of the visual angles subtended by 
 a foot or cavalry soldier, of mean height, at different 
 distances ; but these instruments are considered of little 
 practical value, especially in the excitement of action. 
 Every officer and soldier should be taught to estimate 
 distances by the eye, and in so doing much assistance is 
 derived from knowing what parts of a soldier's dress, or 
 equipments, are visible at certain distances. These data 
 vary with the power of the eye, and each soldier should 
 
TABLES OF FIRE. 447 
 
 be required, by comparison and reflection, to create a 
 standard for his own. 
 
 In firing cannon, the point at which the projectile 
 strikes the ground or bursts, can generally be observed, 
 and from it, the error of aim can be corrected in a few 
 fires ; this, however, does not hold true for small-arm 
 projectiles, which are seldom seen to strike the ground, 
 unless the soil be dusty. 
 
 In the defence of sea-coast batteries, the distances of 
 objects may be determined by their proximity to known 
 objects, as fixed buoys, or by their bearing with refer- 
 ence to prominent landmarks. Plane-tables may be 
 also used to determine the distances of objects. 
 
 The degree of accuracy with which the distance of 
 an object should be known, depends somewhat on the 
 size of the object and the inclination of the trajectory to 
 the line of sight ; if the object be large and the trajec- 
 tory vary but slightly from the line of sight, it is not 
 necessary to know the exact distance, provided the aim 
 be accurately taken. 
 
 TABLES OF FIKE. 
 
 443. Purpose. The nature and purpose of a table 
 of fire should be explained in connection with the sub- 
 ject of pointing cannon. A properly constructed table 
 of fire, for a particular piece, contains the range and 
 time of flight for each elevation, charge of powder, and 
 kind of projectile. Its purpose is to assist the artillerist 
 in attaining his object without waste of time and am- 
 munition, and also when the effect of shot cannot be 
 seen on account of the dust and smoke of the battle- 
 
448 
 
 LOADING AND POINTING FIEE-AEMS. 
 
 field. The first few shots generally produce a great 
 effect on the enemy, and it is very important that they 
 should "be directed with some knowledge of their results, 
 which, in the field, can only be attained by experience, 
 or from the data afforded by a table of fire. 
 
 The following is the form of a table of fire for guns 
 and howitzers : 
 
 KIND OF 
 ORDNANCE. 
 
 POWDER. 
 
 PROJECTILE. 
 
 ELEVATION. 
 
 RANGE. 
 
 TIME. 
 
 Lbs. 
 
 Lbs. 
 
 ' 
 
 Yards. 
 
 Sec'ds. 
 
 
 »f 
 
 29, (solid.) 
 
 5° 0' 
 
 2099 
 
 7.5 
 
 
 
 
 7° 0' 
 
 2894 
 
 9.1 
 
 
 
 
 10° 0' 
 
 3700 
 
 11.6 
 
 Armstrong gun, 
 
 
 
 12° 0' 
 
 4196 
 
 14.2 
 
 4-inch bore. 
 
 
 
 15° 0' 
 
 477G 
 
 17.1 
 
 
 
 
 20° 0' 
 
 6070 
 
 21.4 
 
 
 
 
 25° 0' 
 
 6580 
 
 25. 
 
 
 
 
 30° 0' 
 
 7555 
 
 31. 
 
 
 
 
 35° 0' 
 
 9000 
 
 
 The ranges in the foregoing table were determined 
 at West Point, in 1860, and are the mean of five shots 
 for each angle of elevation. The ranges obtained with 
 the best American muzzle-loading rifle-cannon compare 
 favorably with these. 
 
 Tables of fire, for the different service cannon, may 
 be found in the Ordnance and Artillery Manuals, and 
 the XIII. chapter of this work. 
 
 EAPIDITY OF FIKE. 
 
 444. Depends on size of piece, dec. The rapidity with 
 which cannon can be loaded and discharged depends 
 on the size of the piece, the construction of the carriage, 
 and the care required in aiming. 
 
449 
 
 Field-cannon. Field-cannon can be discharged with 
 careful aim, about twice per minute ; in case of emer- 
 gency, when closely pressed by the enemy, canister-shot 
 may be discharged four times per minute. The 12-pdr. 
 boat-howitzer of the navy, with experienced gunners, 
 can be discharged at the rate of sixteen times per minute. 
 
 Siege-cannon. Siege-guns are generally discharged 
 about twelve times per hour ; if necessary, they can be 
 discharged as rapidly as twenty times per hour. Iron 
 cannon can be fired more rapidly than bronze, as the 
 latter metal is softened by the heat, and the piece is 
 liable to bend. Siege-mortars can be conveniently fired 
 twelve times per hour, and more rapidly than this if 
 the object be large, as a city. Siege-howitzers can be 
 fired about eight times in an hour. 
 
 Sea-coast cannon. The fire of a sea-coast cannon de- 
 pends much on the ease with which its carriage can be 
 manoeuvred. The heaviest, or 15-in. gun, mounted on 
 the new iron carriage, can be loaded and fired in V 10 v ; 
 the time required in aiming depends on the angle 
 through which the chassis is to be traversed, and piece 
 elevated, or depressed ; it can be traversed through an 
 angle of 90° in 2' 20". 
 
 Small-arms. Muzzle-loading small-arms can be dis- 
 charged two or three times in a minute, and breech-load- 
 ing arms about ten times; the revolver can be dis- 
 charged much more rapidly for six shots. 
 
 This quality of a military fire-arm should be carefully 
 guarded, as it is found that soldiers are prone to dis- 
 charge their pieces in the excitement of battle without 
 taking proper aim, and ■ consequently to waste their 
 
 ammunition. 
 
 29 
 
450 DIFFERENT KINDS OF FIEES. 
 
 CHAPTER X. 
 DIFFERENT KINDS OF FIRES. 
 
 445. cia§§iflcation. Artillery fires are distinguished 
 by the manner in which the projectile strikes the ob- 
 ject — as direct, ricochet, rolling, and plunging fires ; by 
 the nature of the projectile, as solid shot, shell, shrapnel, 
 grape, and canister fires; and by the angle of ele- 
 vation, as horizontal fire, or the fire of guns and how- 
 itzers under low angles of elevation, and vertical fires, 
 or the fire of mortars, under high angles of elevation. 
 
 446. Direct nre. A fire is said to be direct when 
 the projectile hits its object before striking any inter- 
 mediate object, as the surface of the ground, or water. 
 This species of fire is employed where great penetration 
 is required, as the force of the projectile is not dimin- 
 ished by previous impact ; it is necessarily employed 
 for spherical-case shot, and for rifle-cannon projectiles, 
 which, from their form, are liable to be deflected, by 
 previously striking a resisting substance ; it is also used 
 for all field-cannon projectiles, when the nature of the 
 ground does not insure a regular rebound. 
 
 To point apiece in direct fire, bring the line of sight 
 to bear upon the object, and then elevate the piece accord- 
 ing to the distance. 
 
 447. Ricochet fire. When a projectile strikes the 
 ground, or water, under a small angle of fall, it pene- 
 trates obliquely to a certain distance, and is then re- 
 
RICOCHET FIRE. 451 
 
 fleeted at an angle greater than the angle of fall ; the 
 reason for this is, that the projectile, in forming the 
 
 furrow, loses a portion of its 
 velocity, making the distance 
 from A (fig. 145), the point at 
 Fig. 145. ' which it enters the ground, to 
 
 O, or the vertical drawn through the deepest point, 
 greater than the distance from C to D, the point where 
 it leaves the ground. 
 
 As this recurs every time the projectile strikes the 
 ground, it follows that the trajectory is made up of a 
 series of rebounds, or ricochets, each one shorter and 
 more curved than the preceding one. 
 
 The number, shaj)e, and extent of the ricochets, de- 
 pend on the nature of the surface struck, the initial 
 velocity, shape, size, and density of the projectile, and 
 on the angle of fall. 
 
 A spherical projectile ricochets well on smooth water, 
 when the angle of fall is less than 8°, but if the surface 
 of the water be rough, very little dependence can be 
 placed on the extent of the ricochet. Captain Dahlgren 
 cites a case as coming under his observation where the 
 distance between the first and second rebound was in- 
 creased from 400 to 800 yards by a strong wind ; at 
 the same time, the height of the highest point of the 
 curve was increased from a very small distance above 
 the water, to more than 50 feet, which would have ren- 
 dered it ineffective against the hull of a ship. From 
 the same causes the lateral deviations in ricochet fire 
 will be very considerable, amounting, in some cases, to 
 between 100 and 200 yards in the entire range. 
 
 In general, those projectiles which present a uniform 
 
452 DIFFERENT KINDS OF FIRES. 
 
 surface, and have the least penetrating power, are most 
 suitable for ricochet firing ; hence, large shells fired with 
 small charges are more suitable than solid shot, and 
 round projectiles more suitable than those of an oblong 
 form. The distance at which the larger size shells will 
 ricochet on water is about 3,000 yards, the axis of the 
 piece being horizontal and near the water. 
 
 Where used, &c. Ricochet fire is employed in siege 
 operations to attain the face of a work in flank, or in 
 
 Fig. 146. 
 
 reverse (see fig. 146), and on the field, or on water, 
 when the object i3 large and its distance is not accu- 
 rately known. 
 
 The character of ricochet fire i3 determined by the 
 angle of fall, or the angle included between the tan- 
 gent of the trajectory and horizon at the point of fall* 
 There are two kinds of ricochet fire — the flattened, in 
 which the angle of foil is between 2° and 4° ; and the 
 curvetted, in which the angle of fall is between 6° 
 and 15°. 
 
 The principal pieces employed in ricochet fire in 
 siege operations are the 8-inch howitzer, and the 8 and 
 10-inch common mortars; the first two may be used 
 when the angle of fall is less than 10°, and the 10-inch 
 mortar when the angle of fall is less than 15° — the 
 proper elevation being given to the mortar by raising 
 the rear portion of the bed. With these pieces, the 
 
PEACTICAL EULES FOE EICOCHET FIEE. 453 
 
 limit of ricochet is about 600 yards. Solid shot should 
 not be used in ricochet fire for any distance less than 
 200 yards, as it would then be necessary to diminish 
 its velocity so much as to destroy its percussive effect. 
 In ricochet firing against troops in the open field, the 
 'O r^ingle of fall should not exceed 3°. 
 
 7/ 448. Practical rules for ricochet Are. In enfilading 
 ^^*The face of a work, the form of the trajectory and point 
 of fall should be such that the projectile will strike the 
 surface of the terreplein the greatest number of times ; 
 the object being to destroy the men, carriages, and 
 traverses situated upon it. To do this, the projectile 
 should be made to graze the crest of the adjacent 
 parapet, and strike the terreplein as near the foot of 
 the interior slope as possible ; the distance of the crest, 
 and its height above the terreplein and battery, should 
 therefore be known. 
 
 The formulas in chapter VIII. furnish accurate means 
 for calculating the various elements of ricochet fire, but 
 they are too complicated for use in the field ; it is there- 
 fore proposed to deduce simple and practical rules for 
 this purpose. 
 
 1st. To find the angle of arrival. The angle of arri- 
 val is the angle which the tangent to the trajectory at 
 the crest of the parapet makes with the horizon. Let 
 
 A be the crest, and B the 
 point of fall (fig. 147); 
 the distance A B being 
 short, the portion of the 
 trajectory included be- 
 tween these two points 
 may be considered a right line, and the angle of fall 
 
454 DIFFEKENT KINDS OF FIEES. 
 
 and arrival will be equal. Calling a the angle of fall, 
 and erecting the perpendicular B (7, we have, 
 
 BO 
 a =ACT 
 or, the tangent of the angle of arrival is equal to the ver- 
 tical distance of the point of fall below the crest, divided 
 by the horizontal distance. 
 
 Within the limits of ricochet fire, the angles may be 
 supposed proportional to their tangents; calling the 
 tangent of 6° (which is 0.1051) 0.1, we have the follow- 
 ing proportion : 
 
 *:6.::Jg:0.1, 
 
 or, 
 
 0=60°^, 
 AC 
 
 or, the angle of arrival is equal to 60° multiplied by the 
 ratio of the horizontal and vertical distances of the point 
 of fall from the crest of the parapet. 
 
 This rule gives the angle of arrival without the aid 
 of a table of natural tangents. 
 
 2d. To find the angle of fire. The distance of the 
 parapet is always known, and the angle of elevation of 
 the crest can be determined by sighting along the long 
 branch of a gunner's quadrant, and observing the posi- 
 tion of the plummet on the arc. 
 
 In consequence of the nearness of the object, and the 
 large size and low initial velocity of the projectile, the 
 resistance of the air in this species of ricochet iire may 
 be neglected, which makes the trajectory a parabola. In 
 this case the angle of fall is equal to the angle of fire, 
 when the object is situated in the same horizontal plane 
 
PRACTICAL RULES FOR RICOCHET FIRE. 455 
 
 with the piece ; if it be not in the same horizontal plane, 
 let BAM (fig. 148), which is the angle of elevation 
 
 Fig. 148. 
 
 of the crest, be represented by e. As the angle e is 
 very small, we are at liberty to suppose C A B=A B C. 
 Through the point B draw the horizontal line B I), the 
 angle C B D is equal to the angle of arrival a; the 
 lines B D and A M being parallel, the angle A B D=e ; 
 therefore C A B — C B A=a+e, but the angle C A M 
 = A B-\-e=a-{-2e : or, the angle of fire is equal to the 
 angle of arrival increased by twice the angle of elevation 
 of the crest of the parapet. 
 
 From the erroneous suppositions made in the course 
 of the preceding demonstrations, it will be seen that 
 the rules deduced should give too great an angle of fire. 
 In practice, this angle should be somewhat greater than 
 the true angle, in consequence of the deviations, which 
 render the projectile liable to strike against the parapet, 
 and, of course, destroy its effect. 
 
 3d. To find the charge. When a projectile moves in 
 vacuo, we have seen that the distance which it falls 
 below the line of fire, in the time t, is \ gt 2 ; and for a 
 given distance, t is inversely proportional to the initial 
 velocity V; hence the distances which the same pro- 
 jectile, fired with different velocities, would fall below 
 the line of fire, in the distance A O (fig. 149), will be 
 inversely proportional to the squares of the initial veloci- 
 
456 
 
 DIFFERENT KINDS OF FIKES. 
 
 Fig. 149. 
 
 If we suppose the lines of fire of two projectiles be 
 A C and A C, and the initial velocities, V and V\ to 
 be such that they will fall the distances B O and B' Q\ 
 and that the angles subtended by these lines be propor- 
 tional to the lines themselves, we shall have 
 BAO.BAC':: V' 2 : V 2 
 
 It has been seen that the initial velocities of small 
 charges are nearly proportional to the square roots of 
 the weight of the charges. Calling the corresponding 
 charges (7 and (?, we have 
 
 B AC : B' A C : : C: C, 
 or, for the same distance of the object, the chaises should 
 be inversely proportional to the difference between the 
 angle of fire and angle of elevation of the object. 
 
 Take the case in which the objects are situated at 
 different distances, as B and B" (jig. 149), but have the 
 same angle of elevation e / and suppose we wish to 
 strike them with the same angle of fire ; what should be 
 the relation between the charges % 
 
 Substitute in the expression \gtf, the value of t, which 
 
 is —, in which D is the distance, and V the initial ve- 
 
 locity of the projectile, we have \g — -^ which shows 
 
 that the distance which a projectile falls below the line 
 of fire is directly proportional to the square of the dis- 
 tance measured on the line of fire, and inversely pro- 
 
PRACTICAL RULES FOR RICOCHET FIRE. 457 
 
 portional to the square of the velocity. But the dis- 
 tances B " C" and B C are proportional to A 0" and 
 A C, or B" and B, and, recollecting that the squares of 
 the initial velocities are proportional to the charges 
 (7 and C", we have 
 
 TV2 7)2 
 
 B" - B- •— • — 
 
 - c»' c 
 
 or, 
 
 &":Z>i: C" : C, 
 
 or, for the same difference between the angle of fire and 
 the angle of elevation of the object, the charges are pro- 
 portional to the distances. 
 
 In arriving at the foregoing rules, we have committed 
 three errors: 1st. Supposing the sides of the triangles 
 proportional to the angles. 2d. Considering the re- 
 sistance of the air nothing; and, 3d. That the initial 
 velocities are proportional to the square roots of the 
 charges. The errors resulting from these suppositions 
 are not only small in themselves, but the 2d and 3d 
 are of a nature to counteract each other. 
 
 By means of the foregoing relations suitable charges 
 can be calculated for every case of practice, when we 
 know the charge corresponding to a given distance, and 
 to a given difference between the angle of fire and the 
 angle of elevation of the object. Represent by C the 
 charge corresponding to a distance, B\ and to a differ- 
 ence, JE\ between the angle of fire and the angle of ele- 
 vation of the object; we have the charge, (7, corre- 
 sponding to the distance, B, and the difference, BJ, be- 
 tween the two angles, by means of the formula 
 
 C~ D x C ' E ' 
 
458 DIFFEKENT KINDS OF FIRES. 
 
 The factor, is a constant number for each cali- 
 bre. This number may be considered as the charge 
 corresponding to the distance of 1 yard, and to a differ- 
 ence of 1° between the angle of fire and of elevation of 
 the object. 
 
 For the French 8-inch siege howitzer, the value of 
 this factor has been found by careful experiment to be 
 0.31 oz. Making an allowance for difference of weight 
 of projectile and unit of distance, it becomes 0.28 oz. 
 for the American 8-inch siege howitzer. 
 
 Example. — Find the angle of arrival, angle of fire, and charge of 
 powder, necessary to hit, with an 8-inch howitzer shell, a point on a 
 terreplein, 12 yards behind a traverse which is 2.5 yards high and 350 
 yards from the battery — the angle of elevation of the crest being 1°, 
 and the command 6 yards. 
 
 For the angle of arrival we have 
 
 B C 60° x 2.5 
 
 ^ 60 ^ == -T2-= 12 ° 30 '- 
 
 For the angle of fire we have 
 
 0==a + 2f=12° 30-f2°==14 o 30'. 
 For the charge we have 
 
 „ D 350. 
 
 tf=^0.28oz. ==—-0.28 = 7.25 oz. 
 
 Hj » lo.O 
 
 449. Roiling fire. Rolling fire is a particular case of 
 ricochet fire, produced by placing the axis of the piece 
 parallel, or nearly so, with the ground. It is generally 
 used in field service. When the ground is favorable for 
 ricochet, the projectile, in rolling fire, has a very long 
 range, and never passes at a greater distance above the 
 ground than the muzzle of the piece; it is therefore 
 more effective than direct fire, as may be seen by in- 
 specting ^g. 150. 
 
EFFECT OF FIRE IN GENERAL. 459 
 
 Fig. 150. 
 
 To point a piece in rolling fire, direct it at the object, 
 and depress the natural line of sight so as to pierce the 
 surface of the ground about 80 yards in front of the 
 muzzle; if the piece be sighted for the pendulum 
 hausse, aim directly at the object with the lowest line of 
 sight, or with the slider fixed at the zero point of the 
 scale. 
 
 450. Plunging fire. A fire is said to be plunging when 
 the object is situated below the piece. This iire is par- 
 ticularly effective against the decks of vessels. 
 
 451. Effect of fire in general. Before proceeding to 
 describe the fires of different kinds of projectiles, it may 
 be proper to explain what is meant by accuracy of fire, 
 and to determine a suitable measure for it. It has been 
 seen that there are causes constantly at work to deviate 
 nearly every projectile from its true path. As the effect 
 of these deviating forces cannot be accurately foretold, 
 there is only a probability that the projectile will strike 
 the object against which the piece is pointed. The de- 
 gree of probability is called accuracy of fire. 
 
 For all projectiles of the same nature, the chance of 
 hitting an object increases with the velocity and weight 
 of the projectile, whereby the effects of the deviating 
 forces are diminished ; it also increases as the size of the 
 object is equal to, or greater than, the mean deviations, 
 and as the trajectory more nearly coincides with the line 
 of sight. If the size of the object be greater than the 
 extreme deviation, and the trajectory coincide with the 
 
460 
 
 DIFFERENT KINDS OF FIRES. 
 
 line of sight, the projectile will be certain to hit the 
 object at all distances. 
 
 452. Measure of deviation. For the same trajectory, 
 therefore, the mean deviation of a projectile at a given 
 distance may be taken as an indirect measure of its ac- 
 curacy at this distance. 
 
 To obtain this mean deviation, let the piece be 
 pointed at the centre of a target, stationed at the re- 
 quired distance, and fired a certain number of times — 
 say ten — and let the positions of the shot-holes, meas- 
 ured in vertical and horizontal directions, be arranged 
 in the following tabular form : 
 
 o 
 
 i 
 
 1 
 
 Distances from centre of target, in feet. 
 
 Distances from centre of impact, in feet 
 
 Vertical. 
 
 Horizontal. 
 
 Vertical. 
 
 Horizontal. 
 
 Above. 
 
 Below. 
 
 Eight. 
 
 Left. 
 
 Above. 1 Below. 
 
 Eight 
 
 Left. 
 
 1 
 
 2 
 3 
 
 3 
 
 6 
 
 1 
 
 4 
 
 2 
 
 2 
 
 4.33 ' 
 
 4.66 
 
 .33 j 
 
 2.66 
 .66 
 
 3.33 
 
 3 
 
 1 
 
 6 
 
 2 
 
 4.66 
 
 4.66 
 
 3.33 
 
 3 33 
 
 4-^3 = 1.33 
 
 4-^3 = 1.33 
 
 9.32 -^ 3 = 3.1116.66 -4-8= 2.22 
 
 The algebraic sum of the distances in each direction, 
 divided by the number of shots, gives the position of 
 the centre of impact in this direction. In the above 
 table the position of the centre of impact is found to be 
 1.33 ft. below, and 1.33 ft. to the right, of the centre 
 of the target. To obtain the mean deviation, it is 
 necessary to refer each shot-hole to the centre of impact 
 as a new origin of co-ordinates ; and this is done by 
 subtracting the tabular distance from the distance of 
 the centre of impact, if both be on the same side of the 
 
DEVIATIONS. 461 
 
 centre of the target, and adding them, if on different 
 sides. The sum of all the distances thus obtained in 
 one direction, divided by the number of shots, gives 
 the mean deviation in that direction ; which in the 
 present case is 3.11 ft. vertically, and 2.22 horizontally. 
 The foregoing affords a measure for the accuracy of 
 fire of the piece and projectile, but it does not afford a 
 measure for marksmanship, the object of which is to di- 
 rect a projectile so as to strike a given point or surface. 
 In target-practice with sporting rifles, the string, or sum 
 of the distances of a certain number of shots, from the 
 point aimed at, is taken as the measure of accuracy. 
 In military arms, marksmanship is measured by the 
 greatest number of projectiles out of a certain number, 
 placed in a target of given size, or placed within a 
 given space surrounding the centre of the target. 
 
 453. Targets. Targets for heavy cannon are made 
 of cotton cloth (or light boards) stretched over two 
 upright poles firmly secured in the ground. The size 
 varies with the distance : for 1,000 yards and upward, 
 it should be about 20 feet high and 40 feet long. 
 Targets for the field service are made of the same 
 materials, about 8 feet high, and from 30 to 40 feet 
 long. Targets for small arms, if permanent, are made 
 of cast-iron ; if portable, of a wrought-iron frame cov- 
 ered with cotton cloth. For distances less than 200 
 yards, they should be 6 feet high and 22 inches broad; 
 beyond this distance, the breadth of a target may be 
 increased by placing two or more of these targets side 
 by side. 
 
 454. Deviations. The vertical deviation of a pro- 
 jectile is generally greater than its corresponding hori- 
 
462 DIFFERENT KINDS OF FIRES. 
 
 zpntal deviation, and this difference increases with the 
 range. As objects against which military projectiles 
 are directed, present a greater extent of surface in a 
 horizontal than in a vertical direction, it "becomes ne- 
 cessary to exercise great care in the selection of the 
 proper angle of fire. If the ground or water in front 
 of the object be favorable to ricochet, the difficulty 
 will be diminished by aiming so that the projectile 
 will strike the object after one or more rebounds. 
 
 455. Solid-shot firing. Solid shot are generally used 
 for percussion and penetration, and, when heated to a 
 red heat, for the purpose of setting fire to wooden 
 vessels or buildings. From their great strength, they 
 can be fired with a large charge of powder, which 
 gives them great initial velocity, and having great 
 density, which diminishes the effect of the resistance 
 of the air, they have great range and accuracy. In 
 firing hot shot, the charge should be reduced, to pre- 
 vent too great penetration, which would exclude the 
 air and render combustion impossible. 
 
 The extreme range of field artillery is about 3,000 
 yards; it is not very effective, however, beyond 1,700 
 yards for the 6-pdr., and 2,100 yards for the 12-pdr. 
 At 600 yards the horizontal deviation of the 12-pdr. 
 is about 3 feet, and at 1,200 yards it is about 12 feet. 
 For the 6-pdr. the deviations are somewhat greater at 
 both distances. 
 
 The service of solid shot demands less skill than 
 that of shells and spherical case-shot, and they are 
 often effective when the latter are rendered non-effect- 
 ive by untimely explosion. 
 
 456. Shell-firing. The diameter and velocity of two 
 
SHELL-FIRING. 463 
 
 projectiles being the same, the retarding effect of the 
 air is inversely proportional to their weight (see page 
 406) ; hence a shell has less accuracy and range than a 
 solid shot of the same size, in the proportion of 3 to 
 2 — these numbers representing the weights of a solid 
 shot and shell, respectively. 
 
 Field s/iells. As shells act both by percussion and 
 explosion, they are particularly effective against ani- 
 mate objects, earthworks, buildings, block-houses and 
 shipping, posts and villages occupied by troops, and 
 against troops sheltered by accidents of the ground; 
 but against good masonry they have but little effect, 
 as they break on striking. Against troops, especially 
 cavalry, they possess a certain moral effect which solid 
 shot do not possess. They are used to form breaches 
 in intrenchments, in which case they act as small 
 mines. The 32-pdr. shell is the most effective field 
 projectile for this purpose; and, when fired with a 
 large charge, has a penetration of from 5 to 8 feet in 
 fresh earth. 
 
 The extreme range of field shells is from 2,500 to 
 3,000 yards. The 24 and 32-pdr. shells burst into 
 about eighteen effective fragments, some of which are 
 thrown to a distance of 600 yards. All field shells 
 have considerable lateral deviation; it is stated that 
 the 24-pdr. shell is sometimes deviated as much as 30 
 yards in 1,200. 
 
 Mountain shells. The extreme range of the moun- 
 tain howitzer is about 1,200 yards, after three or four 
 rebounds. The 12-pdr. shell employed in this service 
 bursts into twelve or fifteen fragments, some of which 
 are thrown to a distance of 300 yards. 
 
464 DIFFERENT KINDS OF FIRES. 
 
 Siege shells. The great weight of an 8-inch shell, and 
 the large quantity of powder which it contains, render 
 it a very formidable projectile against the traverses and 
 epaulements of siege works. 
 
 Sea-coast shells. In sea-coast defence, the 8, 10, and 
 15-inch shells are very destructive to vessels built of tim- 
 ber. They range from 3 to 3| miles; but the angle 
 which the trajectory makes with the line of sight at this 
 distance (about 40°) renders their fire very uncertain 
 against individual objects of the size of a ship ; but it is 
 presumed that they would have the effect to prevent a 
 blockading fleet from lying at anchor within their range, 
 as it is well known that a single 10-inch shell, striking 
 on the deck of a vessel, has sufficient force to penetrate 
 to the bottom and sink her. The 8-inch shell bursts 
 into 28 or 30 fragments; and from the experiments 
 made at Brest, some years ago, it was inferred that three 
 of four of these shells, properly timed and directed, 
 were capable of disabling a ship of war. 
 
 Mortar shells are employed to break through the 
 roofs of magazines, <fec, and to blow them up ; to de- 
 stroy the surface of the terrepleins, ditches, <fcc, by form- 
 ing deep hollows, which are produced by explosion, and 
 to interrupt the communications from one part of a work 
 to another. The great depth to which mortar shells 
 penetrate in earth, almost entirely destroys the effect 
 of their fragments ; some remain buried in the ground, 
 and the others are thrown out at too high an angle to 
 be dangerous. One of the principal objects of traverses, 
 on a terreplein, is to confine the bursting effects of shells 
 within narrow limits. Mortar shells penetrate from 
 half a yard to one yard in earth ; and the amount of 
 
SHRAPNEL FIRING. 465 
 
 earth thrown up by explosion is about one cubic yard 
 for each pound of the bursting-charge. Ordinarily, the 
 diameter of the crater at the top is two or three times 
 the depth. The 13-inch shell will often break in falling 
 on a pavement* Roofs of good masonry, little more 
 than a yard thick, are sufficient to resist the penetration 
 of mortar shells. 
 
 The effect of mortar-firing is generally in favor of the 
 besiegers, as the works of the besieged present a larger 
 and more favorable surface for the action of shells. 
 About one-fifth of the shells fall inside of a demi-lune 
 at a distance of 650 yards, and about one-third at a dis- 
 tance of 450 yards. The line of fire should be taken in 
 the direction of the greatest extent of the part to be 
 shelled. The fire of mortars at sea is veiy uncertain, 
 unless the object be very large. 
 
 Stone mortars. The charge of a stone mortar should 
 be small, to prevent the stones and grenades from being 
 too much scattered. A charge of stones is generally 
 scattered over a space varying from 30 to 50 yards 
 broad, and from 60 to 100 yards long. The dispersion 
 of grenades is somewhat less than this ; the larger por- 
 tion, however, are found within a radius of 12 or 15 
 yards. Each grenade furnishes from 12 to 15 fragments 
 in a radius of 10 or 20 yards ; some of the fragments 
 are projected to a distance of 300 yards. 
 
 45 7. Shrapnel firing. When a shrapnel or case-shot 
 
 bursts in its flight, the fragments of the case and the 
 
 contained jxrojectiles are influenced by two forces, viz., 
 
 the force of propulsion, which moves each piece in the 
 
 direction of the trajectory, and the force of rupture, 
 
 which moves it in the direction of a normal to the sur- 
 30 
 
466 DIFFERENT KINDS OF FIRES. 
 
 face of the case. The path described by each fragment 
 and projectile depends on the angle which the normal 
 makes, with the trajectory, and on the relative velocities 
 
 Fig. 151. 
 
 generated by the two forces ; and, when taken together, 
 these paths form a species of cone, called the cone of dis- 
 persion, the apex of which coincides with the point of 
 rupture, and the axis is the trajectory, prolonged. Fig. 
 151. 
 
 The velocity of a projectile diminishes from the time 
 it leaves its piece, while the velocity generated by the 
 rupturing force remains constant. It follows, therefore, 
 that the dispersion of a spherical case-shot increases with 
 the distance, while the force of impact is diminished. 
 
 The distance at which a spherical case-shot ceases to 
 be effective depends on the relation between the re- 
 maining velocity and the velocity generated by the force 
 of rupture. The improvements which have lately been 
 introduced into this species of projectile, have for their 
 objects, to increase the remaining velocity at any point 
 by increasing the propelling charge, and to diminish the 
 force of rupture, and at the same time increase the num- 
 ber of contained projectiles by diminishing the burst- 
 ing-charge. By filling the interstices of the bullets 
 with sulphur or rosin, the propelling charge of a spher- 
 ical case-shot can be made the same as that of a solid 
 shot. (See chapter II.) 
 
 It is considered that a spherical case-shot is effective 
 when a large portion of the projectiles have sufficient 
 
SHRAPNEL FIRING. 467 
 
 force to penetrate one inch of soft pine. The present 
 12-pdr. spherical case-shot, fired with a charge of 2^ 
 pounds of powder, has a remaining velocity of about 
 500 feet at a distance of 1,500 yards, which renders it 
 effective at this distance. 
 
 The principal difficulty experienced in firing a spher- 
 ical case-shot is, to burst it at the proper distance in 
 front of the object. This arises from the difficulty of 
 estimating the correct distance of the object, the rapid 
 flight of the projectile, and the .difficulty of observing 
 the effect of a shot in order that correction may be 
 made for the succeeding one, if necessary. To overcome 
 these difficulties requires skill and judgment on the 
 part of the gunner, and great accuracy and delicacy in 
 the operation of the fuze. 
 
 The proper position of the point of rupture varies 
 from 50 to 130 yards in front of, and from 15 to 20 feet 
 above, the object. 
 
 The mean number of destructive pieces from a 12-pdr. 
 spherical case-shot, which may strike a target 9 feet 
 high and 54 feet long, situated at a distance of 800 
 yards, is 30. 
 
 The effect of spherical case-shot from rifle-cannon is 
 said to extend upward of 2,000 yards. This arises 
 from the fact that an oblong projectile preserves its ve- 
 locity for a much longer distance than a round one. 
 
 The weight of a spherical case-shot is about the same 
 as a solid shot of the same size, and being fired with the 
 same charge of powder, it can be used for attaining 
 long ranges, in the absence of solid shot. For this 
 purpose the fuze should not be cut. 
 
 Spherical case-shot should not be used for a less dis- 
 
468 DIFFERENT KINDS OF FIRES. 
 
 tance than 500 yards ; although in cases of emergency 
 the faze may be cut so short that the projectile will 
 burst at the muzzle of the piece, in which case it will 
 act like grape or canister shot. 
 
 458. Grape and cani§ter firing. In grape and canis- 
 ter firing, the apex of the cone of dispersion is situated 
 in the muzzle of the piece, and the destructive effect is 
 confined to short distances. The shape of this cone is 
 the same as in spherical case-shot ; its intersection by a 
 vertical plane is circular, while that of a horizontal 
 plane, as the ground, is an oval, with its greatest diam- 
 eter in the plane of fire. The greatest number of pro- 
 jectiles are found around the axis of the cone, while the 
 extreme deviations amount to nearly one-tenth of the 
 range. 
 
 The most suitable distance for field canister-shot is 
 from 350 to 500 yards ; if the ground be hard and the 
 surface be uniform, the effect may extend as far as 800 
 yards. In cases of great emergency a double charge of 
 canister, fired with a single cartridge, may be used for 
 distances between 150 and 200 yards. 
 
 Under favorable circumstances, one- third of the whole 
 number of contained projectiles will strike the size of a 
 half-battalion-front of infantry, and one-half, the front 
 of a squadron of cavalry. 
 
 Grape and canister shot are employed in siege and 
 sea-coast operations ; in the latter, they are effective 
 against boats, and the rigging, <fcc., of vessels. Grape- 
 shot, being larger than canister-shot, are effective at 
 greater distances. 
 
 Canister-shot for the mountain service are not effec- 
 tive beyond 250 and 300 yards. 
 
SMALL-ARM FIRING. 469 
 
 459. Small-arm firing. Beyond 200 yards, the fire 
 of the smooth-bored musket becomes very uncertain 
 against individual objects, as the lateral deviations 
 often exceed four feet ; but by aiming high it may be 
 made effective against troops in mass at 400 yards. The 
 fire of the rifle-musket is effective at 1,000 yards; the 
 angle of fall, however, is so great (about 5°) that great 
 care must be exercised in determining the exact dis- 
 tance of the object. If the ground be favorable, the 
 projectile will ricochet at 1,000 yards, wjiich increases 
 the dangerous space, and therefore the chances of hit- 
 ting the object. The limit of any fire is determined by 
 the distinctness of vision ; — the limit of distinct vision 
 for a foot-soldier is about 1,100 yards ; that for a mount- 
 ed soldier is about 1,300 yards. 
 
 The effect of small-arm firing depends much on the 
 skill and self-possession of the soldier in action ; for, 
 without these qualities, the most powerful and accurate 
 arms will be of little avail. The number of cartridges 
 expended for each person disabled in previous Europe- 
 an wars has been variously stated to be from 3,000 to 
 10,000. In the late Mexican war, where an unusually 
 large proportion of the American troops were armed 
 with rifles, this number has been estimated to be from 
 300 to 400. 
 
 Where a soldier discharges his piece from the back 
 of a horse, as in the cavalry service, the effect of fire is 
 much less than in the dragoon and mounted-rifle ser- 
 vices, where he rides from point to point, but discharges 
 his piece on foot. 
 
 At short distances, and against troops in mass, two 
 or three round bullets may be employed with effect ; 
 
470 
 
 DIFFERENT KINDS OF FIEES. 
 
 the bullets should be so small that they will readily 
 drop to their place without the aid of the ramrod. 
 Buckshot have very little effect beyond 100 yards. 
 
 The following are the mean deviations of the rifle- 
 musket fired from a shoulder and rest. 
 
 DISTANCE. 
 
 VERTICAL. 
 
 HORIZONTAL. 
 
 Yards. 
 
 100 
 
 600 
 
 1000 
 
 Inches. 
 
 1.9 
 22.2 
 55.9 
 
 Inches. 
 
 1.5 
 14.6 
 25.5 
 
 s 
 
 ^(i^d^; 
 
 '^*~* V S 
 
EFFECT ON CAST-IKON. 471 
 
 CHAPTER XL 
 EFFECTS OF PROJECTILES. 
 
 460. General consi derations. A knowledge of the 
 destructive effects of projectiles on iron, wood, earth, 
 and masonry, the materials of which covering masses 
 are made, is of very great importance in a military point 
 of view. In general, these effects, and particularly that 
 of penetration, depend on the nature of the projectile, 
 its initial velocity, and the distance of the object. 
 
 461. Effect on cast-iron. When a projectile, animated 
 with a great velocity, strikes against a block of cast- 
 iron, it is partially flattened, and at the same time it 
 forms a rounded indentation in the surface of the block, 
 the depth of which increases with the velocity at the 
 moment of impact. The particles composing a cone, 
 the base of which is the surface of contact, are arrested 
 by the impact; the remaining particles of the projectile, 
 composing a ring surrounding this cone, move on, after 
 impact, by their inertia, until the ring breaks into pieces, 
 which fly off from the reflecting surface. The ring gen- 
 erally breaks into five pyramidal pieces, separated by 
 as many meridian planes; these pieces are thrown at 
 various distances, depending on the velocity of the pro- 
 jectile and the surface of impact. 
 
 A similar effect is produced upon the piece struck ; 
 that is, a cone of particles, having for its base the surface 
 of contact, is set in motion, which, acting like a wedge, 
 tends to split the mass into five pyramidal pieces. If 
 
472 EFFECTS OF PROJECTILES. 
 
 the velocity of the projectile be not sufficient to produce 
 rupture, cracks will be generally formed in the direc- 
 tions above indicated. 
 
 In certain experiments made in France, a 24-pdr. shot, 
 fired with a charge of T V, and moving with a velocity 
 of 883 feet, split, in two shots, to the depth of 40 inches, 
 a block of cast-iron 12 inches wide by 40 inches deep. 
 The fragments of the block and shot were thrown off 
 with sufficient force to produce the most destructive 
 effect. Hence, cast-iron cannot be safely used for gun- 
 carriages, or the revetments of fortifications. 
 
 462. Effect on wrought-iron. The effect produced 
 by a* projectile striking against a mass of wrought-iron 
 is similar to that produced on cast-iron ; but, in conse- 
 quence of its greater toughness, softness, and malleability, 
 the fragments are not so readily formed, the indentation 
 is deeper, and a portion of the compressed metal is thrust 
 aside, raising the edge of the indentation into a burr. 
 
 The superior toughness and cheapness of this metal 
 have suggested its application as a covering for vessels 
 of war, and numerous trials are now in progress among 
 the principal naval powers of Europe to test its suitable- 
 ness for this purpose. 
 
 The following conclusions have been drawn from the 
 trials thus far completed in England :* 
 
 1st. Thin plates of wrought-iron may serve as a pro- 
 tection against shells of any size. The plates may be 
 penetrated, but the shells are broken by the impact, 
 and therefore rendered harmless, if the woodwork be- 
 hind the plates be sufficient to arrest the fragments. 
 
 2d. The thickness of a wrought-iron plate necessary 
 
 * Vide Sir Howard Douglas, Naval Gunnery, 5th edition. 
 
EFFECT ON WROUGHT-IRON. 473 
 
 to resist heavy solid shot moving with high velocities is 
 not less than 4J> inches. 
 
 The resistance is very much increased by supporting 
 the plate in rear with a mass of stout timber, or some 
 other elastic substance. A plate of wrought-iron 6 feet 
 square and 8 inches thick, standing in an inclined posi- 
 tion against a wall, was broken up by twelve 68-pdr. 
 shots fired with a charge of 16 pounds of powder, at 
 distances of 400 and 600 yards. 
 
 3d. Rifle projectiles, having more momentum, are 
 effective at greater distances than round shot. 
 
 4th. Though iron-plated vessels have been made which 
 are capable of resisting isolated shots from heavy can- 
 non,* none have yet been made fulfilling all the condi- 
 tions of flotation, stability and manageability, which are 
 capable of resisting a simultaneous and concentrated 
 cannonade of 68-pdr. shot, or of rifle projectiles. Such 
 vessels may afford shelter for their crews for a time, and 
 may pass sea-coast batteries with comparative impunity, 
 but it would not be prudent for them to take up a posi- 
 tion near a place guarded by powerful cannon, for the 
 purpose of cannonading it, more especially if the com- 
 mand of the land-batteries gives a j)lunging fire on the 
 vessels. 
 
 The results of the numerous trials have induced the 
 English government to construct several plated vessels ; 
 one of which is to serve the double purpose of a frigate 
 
 * It remains to be determined whether vessels can bo conveniently covered with 
 sufficient thickness of iron to resist the crushing effect of the enormous projectiles 
 of the 15-inch columbiad, or in other words, is it practicable to increase the resist- 
 ance of such iron coverings to keep pace with the increase in the destructive power 
 of projectiles ? Captain Rodman claims, with a show of reason, that if the 15-inch gun 
 bo not sufficient for this purpose, much larger ones can be made, that will suffice. 
 
474 EFFECTS OF PROJECTILES. 
 
 and steam ram. The sides of this frigate are composed 
 of 20 inches of solid teak-wood, covered on the inside 
 with plates £ inch thick, of the best wrought-iron, and 
 on the outside with plates 4£ inches thick, of the same 
 material. The exterior plates are 15 feet long and 3 
 wide, and are united together by a tongue and groove 
 joint. 
 
 Late experiments at Shoeburyness show, that beyond 
 a thickness of f- of an inch, semi-steel plates do not 
 resist the impact of projectiles as well as those made of 
 good wrought-iron, but for less than this thickness, they 
 offer a much greater resistance. It was shown at the 
 same time that, whatever be the angle offered by the 
 surface of the target, the fracture made by the Arm- 
 strong projectiles was the same, although the shape 
 differed somewhat with the angle ; this, probably, was 
 the result of instantaneous concussion. 
 
 Cast and wrought iron projectiles, fired with high 
 velocities against thick wrought-iron plates, are gen- 
 erally broken by impact, while those of puddled steel 
 and homogeneous iron are not much affected by it. 
 
 463. Effect on wood. The effect of a projectile fired 
 against wood varies with the nature of the wood and 
 the direction of the penetration. If the projectile 
 strike perpendicular to the fibres, and the fibres be 
 tough and elastic, as in the case of oak, a portion of 
 them are crushed, and others are bent under the press- 
 ure of the projectile, but regain their form as soon as 
 it has passed by them. It is found that a hole, formed 
 in oak by a ball 4 inches in diameter, closes up again, 
 so as to leave an opening scarcely large enough to 
 measure the depth of penetration. The size of the 
 
EFFECT ON EARTH. 475 
 
 hole and the shattering effect increase rapidly for the 
 larger calibres. A 9-inch projectile has been found to 
 leave a hole that does not close up, and to tear away 
 large fragments from the back portion of an oak target 
 representing the side of a ship of war, the effect of 
 which, on a vessel, would have been to injure the crew 
 stationed around, or, if the hole had been situated at 
 or below the water line, to have endangered the vessel. 
 If penetration take place in the direction of the 
 fibres, the piece is almost always split, even by the 
 smallest shot, and splinters are thrown to a considera- 
 ble distance. 
 
 In consequence of the softness of white pine, nearly 
 all the fibres struck are broken, and the orifice is nearly 
 the size of the projectile ; for the same reason, the 
 effects of the projectile do not extend much beyond 
 the orifice ; pine is therefore to be preferred to oak for 
 structures that are not intended to resist cannon pro- 
 jectiles, as block-houses, <fcc. 
 
 464. Effect on earth. To determine the shape of 
 the orifice made by a projectile in a substance which 
 
 retains its form, let 
 C C\ fig. 152, repre- 
 sent a projectile pene- 
 trating the substance 
 Fi s- 152 « in the direction of 
 
 the arrow. The friction of the particles, as they move 
 over the surface of the projectile, depends on the nor- 
 mal pressure, which diminishes from the point imme- 
 diately in front to those on the extreme sides, where it 
 is nothing. For the distances A C and A C , the fric- 
 tion will be so great that the included particles will 
 
476 EFFECTS OF PROJECTILES. 
 
 not move over the surface, but they will constitute 
 the base of a cone of matter, C A. C, that will be 
 pushed forward in front of the projectile. Particles 
 situated beyond C and C will be thrown off from 
 the surface, in a tangential direction, with a velocity 
 depending on the position of the particle and the ve- 
 locity of the projectile. 
 
 Take the case of the particle adjacent to C. Let 
 D C represent the velocity of the projectile, and F C 
 the direction of the tangent; the side C E, of the 
 rectangle constructed on D CJ will represent the veloc. 
 ity impressed on the particle, in the direction at right 
 angles to the penetration. 
 
 The velocity CE varies with the velocity D E, which 
 rapidly diminishes from the moment of striking. It 
 follows, that an element of the surface of the orifice 
 formed by a projectile in a plastic substance is curved, 
 and has its convexity turned toward the projectile. 
 
 Earth possesses advantages over all other materials 
 as a covering against projectiles; it is cheap and easily 
 obtained, it offers considerable resistance to penetration, 
 and to a certain extent regains its position after dis- 
 placement. It is found by experience that a projectile 
 has very little effect on an earthen parapet, unless it 
 passes completely through it, and that injury done by 
 the enemy's artillery by day can be promptly repaired 
 at night. Wherever masonry is liable to be breached, 
 it should be masked by earthworks. 
 
 465. Penetration. The resistance which a projectile 
 encounters in penetration, arises from the cohesion and 
 inertia of the particles, and the friction of the particles 
 against the surface of the projectile. 
 
PENETEATION. 477 
 
 To obtain an expression for the penetration, we will 
 suppose that the resistance is proportional to the area 
 of the cross-section of the projectile, and independent 
 of the velocity. Let E be the penetration expressed in 
 calibres, D the density of the projectile, v its velocity 
 at the commencement of penetration, r the radius of the 
 projectile, and H the constant resistance experienced by 
 a unit of surface ; the quantity of work done in over- 
 coming the resistance is, 
 
 nr\U. 2r.fi; ^^Vi) 
 
 and the living force of the projectile is ^ ^ /v/i c 
 
 4 3 D 2 
 
 -nr 6 V . 
 
 3 9 
 
 But the living force is equal to twice the quantity of 
 work ; hence we have, 
 
 3 g 
 
 by making K= we obtain, 
 
 ZKg 
 
 U=Xv 2 D. 
 
 Take another projectile, having a velocity v', a den- 
 sity d, and a penetration e, and we have the expression, 
 e= Kv^d. Dividing the preceding expression by this, 
 member by member, and we have, 
 
 vjd 
 that is to say, the penetrations of different spherical pro- 
 jectiles into a given substance, are proportional to the 
 squares of the velocities of impact, and to the diameters* 
 and densities of the projectiles. 
 
 * The diameters of all service projectiles are given in the Ordnance Manual. 
 
478 EFFECTS OF PEOJECTILES. 
 
 Knowing, therefore, the penetration e, for a given 
 velocity and projectile, we can obtain the penetration 
 E, for another projectile and velocity. Let e represent 
 the penetration for a shot moving with a velocity of 
 1,650 feet, the expression becomes, 
 
 1650 d 
 This formula has been found by experience to give, 
 with sufficient accuracy, the penetration of projectiles in 
 hard substances, as wood, cast-iron, and masonry, for all 
 velocities up to 1,000 feet per second. The following 
 penetrations, or values of £, have been found for solid 
 shot moving with a velocity of 1,650 feet, viz. : 
 
 Cast-iron (depending on its nature), ' \ to \ 
 Lead, . . ' . . . 3j- to 3£ 
 
 Calcareous rocks (particular kind), . 2 
 Masonry of good quality, . . .4 
 
 " rubble, . . . 5 to 5| 
 
 " brick, . . .' . .8 
 
 Substituting the above values of e in the value of E, 
 we obtain the penetrations, expressed in terms of the 
 diameter of the projectile, for any velocity not exceed- 
 ing 1,000 feet. 
 
 Solid shot are broken, when fired against very hard 
 substances, with charges exceeding the following, viz. :* 
 
 Against cast-iron, . . . T ~ 
 
 lead, 1 
 
 " calcareous rock (oolitic), . } 
 
 " masonry, I 
 
 * Some shot resist these charges. 
 
PENETRATION. 479 
 
 The velocity v, is the velocity which the projectile 
 possesses at the commencement of penetration; if the 
 piece be situated at a distance, it is necessary to deter- 
 mine the remaining velocity, by making allowance for 
 the resistance of the air. Equation (20), page 408. 
 
 v 2 D 
 Wood. The formula E— e — > may be used to 
 
 1650 2 d 
 calculate penetrations in wood, for velocities which do 
 not exceed 1,000 feet, making use of the following 
 values of e for penetrations perpendicular to the fibre : 
 
 For oak of ordinary quality, . . e=.Vl\ 
 
 " elm, 16 
 
 " pine, 23 
 
 For velocities exceeding 1,000 feet, the formula just 
 employed gives results which are too large ; from this 
 it is inferred that penetration really increases less rapid- 
 ly than the square of the velocity. 
 
 Earth. In the experiments made at Metz, in 1834, 
 on various kinds of earths, it was found necessary to 
 modify this expression for penetration. Calling p the 
 weight of the powder, and m the weight of the projec- 
 tile, the expression becomes, for all charges between 4- 
 and T V, 
 
 _ lo K 1+480x £ )i> y{ l +^^ D 
 
 ■ E - e log^(l-\-4:S0x^)d~ e , 2.20683 d' 
 
 The following values of e, for a charge of |, were 
 found for different earths : 
 
 For sand mixed with gravel, . 6=sl0j- 
 
 For earth, settled, . . . Wj 
 
480 EFFECTS OF PROJECTILES. 
 
 Potter's clay, saturated with water, . 36 
 Light earth newly dug over, . . 32-^ 
 
 The penetration being given in terms of the weight 
 of the powder and projectile, the piece should be suffi- 
 ciently long to obtain the full force of the charge, or 
 from 17 to 20 calibres; or, in other words, the expres- 
 sion is only suited to field and siege guns. 
 
 In general, sand, sandy earth mixed with gravel, small 
 stones, chalk, or tufa, resist shot better than the produc- 
 tive earths, or clay, or earth that retains moisture. 
 
 Water. To obtain penetration in water, replace 
 
 480^. by 4800^-, and make e equal to 275 calibres. 
 m m 
 
 In some late experiments, it was found that the Whit- 
 worth projectile had sufficient force, at short distances, 
 to pass through 33 feet of water and then penetrate 12 
 or 14 inches of oak beams or scantling. The penetra- 
 tion of a rifle-projectile in water, depends much on the 
 direction of its axis with respect to penetration, for in- 
 stance, penetration rapidly diminishes at long distances, 
 as the axis of the projectile strikes the surface of the 
 water under a diminished angle. 
 
 466. Effect on masonry. The effect of a projectile 
 against masonry, is to form a truncated conical hole, 
 
 terminated by another of a 
 cylindrical form. (See fig. 
 153.) The material in front 
 of and around the projec- 
 ts- 153 - • tile is broken and shatter- 
 ed, and the end of the cylindrical hole even reduced to 
 powder. Pieces of the masonry are sometimes thrown 
 
BREACHING. 481 
 
 50 or 60 yards from the wall. The elasticity developed 
 by the shock, reacts upon the projectile, sometimes 
 throwing it back 150 yards, so as to be dangerous to 
 persons in a breaching battery. The exterior opening 
 varies from 4 to 5 times the diameter of the projectile, 
 and the depth, as we have seen, varies with the size and 
 density of the projectile, and its velocity. 
 
 With charges of -*-, -|, |, and |, a projectile ceases to 
 rebound from a wall of masonry when the angles, formed 
 by the line of fire and the surface of the wall, exceed 
 20°, 24°, 33°, 43°, respectively. With these angles, the 
 angle of reflection is much greater than the angle of 
 incidence, and the velocity after impact is very slight. 
 
 When a projectile strikes against a surface of oak, as 
 the side of a ship, it will not stick if the angle of inci- 
 dence be less than 15°, and if it do not penetrate to a 
 depth nearly equal to its diameter. 
 
 Solid cast-iron shot break against granite, but not 
 against freestone or brick. Shells are broken into small 
 fragments against each of these materials. 
 
 467. Breaching. Escalade being ordinarily very dif- 
 ficult, particularly when the besieged are aware of the 
 intention of the besiegers, the latter are generally com- 
 pelled to destroy a portion of the face of the work to 
 obtain an entrance. Such an opening is called a breach; 
 and to effect it with artillery, particularly in a well- 
 constructed work, where no part of the scarp-wall is 
 visible from the adjacent ground, within effective range 
 of siege-cannon, breaching-batteries are established either 
 on the crest of the covered vjay, or on the glacis. 
 
 When the walls of fortified places were very high 
 
 and not supported by terraces or ramparts, stone pro- 
 31 
 
482 EFFECTS OF PKOJECTILES. 
 
 jectiles were used. From the want of sufficient hardness 
 in these projectiles, the besiegers were forced to com- 
 mence battering at the top of the wall where the least 
 resistance was offered, and gradually to lower the shot 
 until the breach reached the wrecks already formed at 
 the base of the wall. When the style of fortification 
 was changed, this operation became very laborious, the 
 ascent was very steep, and the breach was often imprac- 
 ticable. This method was abandoned and mining sub- 
 stituted. Iron projectiles superseded stone, and then a 
 more rapid mode of effecting a practicable breach was 
 suggested and confirmed by experience. 
 
 Vauban recommended increasing the size of the hole 
 first formed, by continually firing at its sides until the 
 wall should fall ; but the ball was found to glance into 
 it, and injure but slightly the untouched portion of the 
 revetment. The best mode, however, as found by ex- 
 periment, is to cut the wall up into detached parts, by 
 making one horizontal and several vertical fissures, and 
 battering each part down separately. (Fig. 154.) 
 
 The easiest mode of making 
 
 the cut is to direct the shots 
 
 upon the same line, and form 
 
 a series of holes (Jig. 154), a 
 
 Fig. 154. little greater than a diameter 
 
 apart, and then to fire a second series of shots, directed 
 
 at the intervals between the first, and so on, until an 
 
 opening is made completely through the wall. 
 
 The first cut is made horizontally, and finished, which 
 will be known by the earth falling through it ; the ver- 
 tical cuts are then made, there being one at each end of 
 the intended breach. These cuts are commenced at the 
 
BREACHING. 483 
 
 horizontal cut, and raised until the wall, isolated from 
 its supports, sinks, overturns, and breaks into pieces, 
 which become covered by falling earth. If the earth 
 be sustained by its tenacity, loaded shells are fired into 
 it, which, acting like small mines, cause it to fall, and 
 make the breach practicable, or of easy ascent. 
 
 If the portion of the wall between the vertical cuts 
 should not be overthrown by the pressure of the earth 
 behind, it must be detached by a few volleys of solid 
 shot, fired at its centre. This will speedily bring it 
 down in a mass. The moment the wall is down, and 
 the parapet destroyed, the breach will be as perfect, 
 and the slope as easy of ascent, as it can be made by 
 the fire of the batteries. It is important to determine 
 the height of the horizontal cut above the bottom of 
 the ditch, for, if this height be not properly chosen, the 
 breach may be difficult, if not impracticable. If too 
 high, the ramp composed of the debris will be inter- 
 cepted by a portion of the wall ; if too low, the open- 
 ing will be masked by the debris, and the formation of 
 the cut impeded. The most suitable height is nearly 
 equal to the thickness of the wall where the cut is 
 established. The thickness, where not known, can be 
 deduced from the dimensions necessary to be given 
 to the wall, to resist the pressure of the earth of the 
 rampart and parapet. 
 
 The time necessary to make a breach, depends on the 
 size of the breach to be made, the material of the scarp, 
 the number of guns, &c. For a breach of 20 to 30 
 yards in length, at forty yards from the battery, 1,500 
 shot of large calibre will be required ; but when the 
 battery is at a greater distance, a greater number of 
 
484 EFFECTS OF PROJECTILES. 
 
 projectiles will be necessary, on account of the dimin- 
 ished accuracy and penetration. Thus, at 500 or 600 
 yards 9,000 to 10,000 may be needed. 
 
 Rules, The following general rules should be ob- 
 served in firing to effect a breach : — 
 
 1. Ascertain as accurately as possible the widths of 
 the ditch and covered way, the height of the scarp- 
 wall, the thickness of the parapet, the height of the 
 counterscarp, and crest of the covered way. By the 
 aid of a profile that can be constructed from this data, 
 determine the height of the horizontal cut to be made 
 in the scarp, so that the slope of the ramp shall be 45°. 
 This height should never be below a fourth of that of 
 the scarp, and, to avoid interference from the wrecks, it 
 should be nearly equal to the presumed thickness of the 
 wall at the cut. If the ditch be a wet one, commence 
 cutting at the water's edge. 
 
 2. From the number of pieces with which the bat- 
 tery is to be armed, and the length of the breach, de- 
 termine the field of fire of each piece, and the length of 
 cut that it is to make. 
 
 3. Ascertain the angle of elevation, or depression, for 
 each piece, to strike the cut, and mark it unalterably on 
 the elevating screw. 
 
 4. Direct each piece on the right or left of the part 
 to be cut, and space the shot from right to left, or 
 from left to right, at If to 1^ yards for the 24-pdr., 
 and 1 yard for the 18-pdr. Mark on the platform the 
 direction of the stock and wheels at each shot. Re- 
 turning then from left to right, or from right to left, 
 fire at the middle of the intervals left by the first shot, 
 and mark the directions as before. Continue this firing 
 
i 
 BREACHING WITH RIFLE-CANNON. 485 
 
 regularly at the most prominent points, and make the 
 cut progress equally throughout. 
 
 5. Fire at the horizontal cut until the earth falls 
 throughout the cut. 
 
 6. Determine the number of vertical cuts to be made, 
 at the rate, at most, of one to a piece, without spacing 
 more than 10 yards apart, in order that no part shall 
 be sustained by more than one counterfort. Fire as in 
 the case of the horizontal cut, commeDcing at the upper 
 line. 
 
 7. See that the extreme vertical cuts progress as 
 rapidly as the interior ones, and direct the adjoining 
 guns upon them if necessary. 
 
 8. If the wall do not fall after the cuts are made, 
 fire a few volleys at the middle of the spaces thus out- 
 lined. 
 
 9. After the fall of the wall, break down the coun- 
 terforts, and, if time or resources permit, replace the 
 guns by 8-inch howitzers, and fire upon the earth with 
 loaded shells, or fire shells from the guns. 
 
 468. Breaching with rifle-cannon. The superior 
 breaching-power of rifle-projectiles depends not only 
 on penetration, but on great accuracy of flight, whereby 
 they can be quickly concentrated on any desired point. 
 This has been satisfactorily shown by an experiment 
 lately made in England with Armstrong guns, throw- 
 ing projectiles of 40, 80, and 100 lbs. weight, respec- 
 tively. 
 
 The subject of the experiment was a Martello tower, 
 30 feet high, and 48 feet diameter; the walls were 
 from 7 feet 3 inches to 10 feet thick, of solid brick 
 masonry of good quality. The distance was 1,032 
 
486 EFFECTS OF PROJECTILES. 
 
 yards — more than twenty times the usual breaching 
 distance. 
 
 The 80-pdr. shot passed completely through the ma- 
 sonry (7 feet 3 inches), and the 40-pdr. shot and 
 100-pdr. percussion shells lodged in the brick- work, at 
 a depth of five feet. After firing 170 projectiles, a 
 small portion of which were loaded shells, the entire 
 land-side of the tower was thrown down, and the inte- 
 rior space was filled with the debris of the vaulted 
 roof, forming a pile which alone saved the opposite 
 side from destruction. 
 
 It is not presumed that the introduction of rifled siege 
 cannon will change the principles of breaching, as laid 
 down in the preceding section, but it will compel the 
 defence to strengthen his works by the various appli- 
 ances known to the engineer's art. 
 
 469. Effect of buiiet§. The penetrations of the rifle- 
 musket bullet, in a target made of pine boards, one inch 
 thick, are as follows : — 
 
 At 200 yards 11 inches. 
 
 " 600 yards 6| « 
 
 " 1,000 yards 3| a 
 
 From experiments made in Denmark, the following re- 
 lations were found, between the penetration of a bullet 
 in pine and its effects on the body of a living horse, viz. : 
 
 1st. When the force of the bullet is sufficient to pene- 
 trate .31 in, into pine, it is only sufficient to produce a 
 slight contusion of the skin. 
 
 2d. "When the force of penetration is equal to 0.63 
 in., the wound begins to be dangerous, but does not 
 always disable. 
 
EFFECT OF BULLETS. 487 
 
 3d. When the force of penetration is equal to 1.2 
 inch, the wound is very dangerous. 
 
 It will thus be seen, that the present bullet is capable 
 of producing very dangerous wounds at a much greater 
 distance than 1,000 yards. 
 
 A rope matting or mantlet, 3^ inches thick, is found 
 to resist small- arm projectiles at all distances ; it may, 
 therefore, be employed, as it was at the siege of Sebas- 
 topol, to screen the gunners of siege batteries from the 
 enemy's riflemen, 
 
 A field-cannon ball has sufficient force to disable 
 seven or eight men at a distance of 900 yards. It is 
 stated that a single cannon-ball, at the battle of Zorn- 
 dorf, disabled forty-two men — distance not given. 
 
488 EMPLOYMENT OF FIELD-AKTILLEKY. 
 
 CHAPTER XII. 
 EMPLOYMENT OF FIELD-ARTILLERY.* 
 
 470. Oreatest range. The extreme range of field-ar- 
 tillery has been stated to be about 3,000 yards ;f a some- 
 what greater range than this can be obtained by sinking 
 the trail of the carriage into the ground, thereby in- 
 creasing the elevation of the piece; but in consequence 
 of the great strain thus thrown upon the carriage, and 
 the great inaccuracy of the fire, it should be seldom re- 
 sorted to, unless it be to produce a moral effect on an 
 army in retreat, or passing a defile. If employed against 
 an enemy acting on the offensive, it would have the ef- 
 fect, from its extreme inaccuracy, to give him increased 
 confidence. 
 
 In general terms, firing at long range should only be 
 employed when the nature of the ground, or the short- 
 ness of the time, does not permit a nearer approach to 
 the object; and it should always cease when the object 
 of the fire is attained. 
 
 Effective range. The greatest effective range of field- 
 artillery varies from 1,400 to 1,800 yards. Batteries of 
 position belonging to an army acting on the defensive, 
 should open fire at a distance of 1,300 or 1,400 yards. 
 The object of this fire is not so much to arrest, as to re- 
 tard, the movement of the enemy, and compel him to 
 establish batteries to cover his approach. The distances 
 
 * Vide Decker's Instruction Pratique, &c. 
 
 f The ranges in this chapter refer to smooth-bored rather than rifled guns. The 
 principles, however, involved in it, are equally applicable to both. 
 
GREATEST RANGE. 489 
 
 should be carefully estimated, and the firing should take 
 place slowly, in order that the effect of each shot may 
 l>e observed, and the aim corrected, if necessary. 
 
 Rapid and continuous firing should commence at a 
 distance of 800 or 1,000 yards; the attacking party 
 should, at the same time, establish his batteries to cover 
 the deployment of his columns, and to enable him to 
 make the necessary preparations for attack. 
 
 At a distance of 600 or 700 yards, or point-blank 
 distance, the fire becomes very destructive; generally 
 not more than six or eight shots can be fired before one 
 of the parties will either advance or retire. As the 
 distance closes, canister-shot should replace round-shot, 
 which generally ends in producing disorder. 
 
 Against infantry. Formerly artillery could take up 
 a position about 300 or 400 yards in front of infantry 
 without serious loss; but the introduction of the rifle- 
 musket has produced a very great change in the relative 
 powers of these two arms. The experiments made at 
 the musketry-school at Hythe, show conclusively that 
 artillery cannot long maintain a position within half a 
 mile of properly instructed skirmishers, as the fire of 
 rifle-musketry at this distance is as effective as that of 
 canister at 250 or 300 yards. 
 
 Should the surface of the ground be broken, or of 
 such nature as to afford shelter to skirmishers, the pre- 
 ponderance will be still more in their favor. And should 
 the artillery not succeed in silencing the fire of the 
 skirmishers by well served case-shot, it will be obliged 
 to retire beyond the reach of the rifles, and trust to the 
 effect of round and spherical case-shot upon the enemy's 
 masses. 
 
490 EMPLOYMENT OF FIELD- ARTILLEKY. 
 
 Against cavalry. Cavalry, in charging upon an 
 enemy situated at a distance of 1,000 yards, pass over 
 the intervening space in about seven minutes. Each 
 piece may fire nine rounds of solid shot, or spherical 
 case-shot, in the first 400 yards, two solid and three 
 canister shot in the next 400 yards, and two rounds 
 of canister-shot while passing over the remaining 200 
 yards, making a total of eleven round and five canister 
 shot. Neither spherical case-shot nor shells should be 
 fired against cavalry in rapid motion ; and care should 
 be taken not to cease firing solid shot too soon in order 
 to commence firing canister. 
 
 471. Employment of different kinds of Are. The fol- 
 lowing circumstances should be known, to enable the 
 artillerist to select the most suitable fire for a particular 
 occasion: 1st. The distance of the enemy. 2d. The 
 conformation and quality of the intervening ground. 
 3d. The formation of the enemy, as far as can be seen 
 or judged of. 
 
 Direct fire. Direct fire should be employed wherever 
 the surface of the ground is uneven and the quality of 
 the soil varied, or wherever a portion fired over is 
 smooth and the remainder broken, or the soil soft and 
 light. There are other special cases where direct fire 
 should be employed : 
 
 1st. When the enemy is so situated as to conceal the 
 depth of his formation; otherwise the ground in rear 
 of his front line may be such that the ricochet will not 
 take effect ; 
 
 2d. When the enemy is about to pass a defile, and 
 the head of the column only is seen ; or when the 
 depth of the column can be seen, by being commanded 
 
EMPLOYMENT OF DIFFERENT KINDS OF FIRE. 491 
 
 or overlooked; in this case, the projectile which would 
 miss the head might strike the middle or the rear of the 
 column ; 
 
 3d. It should be employed in all sustained cannon- 
 ades, because the effect of its shots can be more easily 
 distinguished than that produced by the shots of a 
 rolling fire. The aim should be corrected by observing 
 the point of fall of the projectile; and, for this purpose, 
 it is desirable to take the mean of three shots. If a 
 rolling fire be employed under these circumstances, the 
 character of the ground and formation of the enemy 
 may be such, that the cannonade may be carried on for 
 hours without knowing what effect is produced. 
 
 To produce good results with direct fire, it is abso- 
 lutely necessary to ascertain the exact distance of the 
 enemy, which can only be done by a practised eye. 
 This circumstance will be appreciated when we con- 
 sider that, if a shot only strike the ground fifteen yards 
 in front of a target six feet high, it will pass completely 
 over it. 
 
 When the object is not on the same level with the 
 piece, the character of the fire will be determined by 
 the nature of the intervening ground. 
 
 If the surface be uniform, and have an inclination 
 to the horizon not exceeding 15°, above or below, no 
 change need be made in the kind of fire, or elevation 
 of the piece, from what they would be on horizontal 
 ground. 
 
 If the enemy be posted on a mountain, or in a valley, 
 the direct fire can only be used. As it is often difficult 
 to estimate the distance, the pieces should be aimed 
 with great precision, and the point of fall should be 
 
492 EMPLOYMENT OF FIELD-AETILLEEY. 
 
 carefully noted ; the firing should be deliberate, and it 
 should be recollected that a different height of sight is 
 necessary than when the object is on level ground. 
 
 472. Ricochet fire. Ricochet fire should never be 
 used for a less distance than 1,000 yards, even when the 
 ground is favorable; for, in order that this fire may 
 produce its greatest effect, it is necessary that the pro- 
 jectile should make two or three rebounds in front of 
 the enemy, which it rarely does at a less distance than 
 1,000 or 1,100 yards. If the ground, for 300 or 400 
 yards in front of the pieces, be soft and uneven, or if it 
 be soft and uneven for 100 or 300 yards in front of the 
 enemy, rolling fire, which is a species of ricochet fire, 
 cannot be employed with effect. 
 
 Large and deep objects, as a mass of troops, a park, 
 or a column of artillery on the march, are the most suit- 
 able objects for ricochet fire, as these objects present 
 several lines, one behind the other. 
 
 473. canister fire. The fire of canister does not 
 always produce the effect anticipated for it, for the fol- 
 lowing reasons, viz. : 
 
 1st. The object is thought to be nearer than it really 
 is, and the firing sometimes commences too soon. 
 
 2d. The danger is often thought to be more imminent 
 than it really is, and, consequently, proper care is not 
 observed in aiming. 
 
 3d. The character of the ground is not properly ap- 
 preciated ; and too much confidence is reposed in the 
 effect of the projectiles thrown over unfavorable ground. 
 
 474. Field-howitzers. The extreme range of shells 
 fired from field-howitzers has been stated to be from 
 2,500 to 3,000 yards. The deviation of shells at ex- 
 
LONG RANGES. 493 
 
 treme distances is so great that they should only be 
 employed against large objects, as cities, camps, &c. 
 
 The greatest effective range of howitzer-shells is about 
 1,500 yards ; shells should only be employed at this 
 distance in the offence, and then, rather as an exception 
 to the general rule. 
 
 The gun should always be employed when capable of 
 producing the same effect as the howitzer. 
 
 Shells act by percussion, by explosion, and by moral 
 effect ; and they should be employed in preference to 
 shot under the following circumstances, viz. : 
 
 1st. When the enemy is stationary and under cover. 
 
 2d. When the ground is much broken, or cannot be 
 seen. 
 
 3d. When troops are posted in woods. 
 
 4th. From one mountain to another. 
 
 5th. When the enemy is posted on higher or lower 
 ground. 
 
 6th. When on a road leading through a valley. 
 
 7th. For incendiary purposes. 
 
 8th. In pursuit. 
 
 9th. Whenever it is necessary to produce a moral 
 rather than a physical effect. 
 
 EMPLOYMENT OF SIEGE-CANNON. 
 
 In siege operations, the same fires are employed as 
 in the field, but under different circumstances. The 
 position of the object is generally fixed and known, 
 and there is sufficient time to consider the best means 
 of attaining it. 
 
 475. Long ranges. The greatest range of the 24-pdr. 
 
494 EMPLOYMENT OF FIELD-ARTILLERY. 
 
 siege-gun, mounted on its appropriate carriage, is about 
 3,500 yards; but the defence should not, without good 
 reason, make use of a greater distance than 950 yards, 
 or point-blank distance, for it is his duty to economize 
 his ammunition, if it cannot be replaced. 
 
 It will be proper to fire at a reconnoitring party 
 at a distance of 1,000 or 1,100 yards, to prevent a 
 nearer approach, and against strong attacking columns, 
 provided they offer sufficient surface to render the 
 chances of hitting probable. 
 
 In the attack. Firing at long ranges, on the part 
 of the besiegers, should be strictly forbidden, as it 
 would disclose to the enemy the proposed front of 
 attack, without any compensating advantage. 
 
 In the siege service, it is more important to avoid 
 useless firing than in the field, for every shot that does 
 not contribute to the progress of the attack, by weaken- 
 ing the defence, is a shot lost. 
 
 476. Enfilading and counter flre§. An enfilading fire 
 is directed along a particular portion of a work, and a 
 counter fire is directed toward it. 
 
 In tlie defence. Solid shot are used in enfilading and 
 counter fires under the following circumstances : 
 
 1st. To destroy the head of a sap, or the parapet of 
 a trench. 
 
 2d. When the enemy passes from the first to the 
 second parallel, and before he has completed the bat- 
 teries intended to dismount the artillery of the garrison. 
 
 3d. To batter vigorously the lateral works of attack 
 as soon as they are finished. 
 
 4th. To protect and support sorties. The guns placed 
 on the parapet of the place keep up a warm fire of 
 
ENFILADING AND COUNTER FIRES. 495 
 
 solid shot against the batteries of attack, and the 
 heads of saps, until they are masked by the troops 
 making the sortie. 
 
 5th. To prevent the enemy from following too closely 
 upon the heels of the party, which, having made the 
 sortie, are returning, successful or otherwise. 
 
 6th. From the guns placed on the flanks of the bas- 
 tions when the besiegers attempt to pass the ditch ; in 
 this case the fire is plunging. 
 
 7th. To drive the besiegers from any outwork that 
 they may have taken. 
 
 8th. In a cannonade, the object of which is to dis- 
 mount the besiegers' guns. 
 
 In the attach. The object of enfilading fire in the 
 attack of a place, is to rake the terrepleins of the 
 faces, curtains, &c, and to render them untenable ; for 
 this purpose the batteries should be established on the 
 prolongation of, and at right angles, or nearly so, with 
 the direction of the part to be enfiladed. As the por- 
 tion of the works to be attained is not commanded by 
 the besiegers' cannon, enfilading fire, under these cir- 
 cumstances, becomes ricochet fire, the nature and treat- 
 ment of which have already been described. 
 
 Enfilading and counter batteries are generally es- 
 tablished at 300 or 600 yards from the place, or at the 
 first and second parallels. As the object of a counter 
 battery is to silence the fire of the place by dismount- 
 ing the guns, its pieces should be directed against the 
 embrasures. 
 
 This demands great care in aiming, and great accuracy 
 of fire ; the heaviest smooth-bored or rifled guns should 
 therefore be employed for this purpose. 
 
496 EMPLOYMENT OF FIELD-ARTILLERY. 
 
 477. Firing in breach. When the besiegers have 
 approached to a suitable distance to commence the 
 breach, the opposing artillery will have been silenced; 
 but they will be subjected to flank and rear fires, 
 against which they will protect themselves by traverses. 
 Counter-batteries will also be established with the 
 breaching- batteries, the object of which will be to silence 
 the artillery bearing on the breaching-batteries, and the 
 passage of the ditch. The method of forming a breach 
 has already been described. 
 
 478. Fire of ca§e-§hot. Case-shot should be employed 
 in the defence of a work under the following circum- 
 stances, viz. : 
 
 1st. In sorties, where field-artillery can be employed. 
 
 2d. At all points liable to sudden attacks, as on 
 avenues leading toward gates, or on bridges. Pieces 
 situated on the flanks are particularly suited to this 
 fire. 
 
 3d. Against the gorge of an outwork which the enemy 
 may make a bold attempt to seize. For this purpose, 
 pieces on the curtains, or shoulder angles, should be 
 employed, taking care, at the same time, not to fire over 
 works occupied by the defence. 
 
 4th. This fire may be safely employed in the defence 
 of dry ditches, reveted with masonry. 
 
 5th. Against the batteries of the first parallel during 
 their erection, and after their position has been disclosed 
 by means of fire-balls. 
 
 6th. Against the head of a sap at night. 
 
 7th. Against the workmen engaged on the construc- 
 tion of the second parallel. 
 
 8th. Against the workmen engaged on the third par- 
 
FIRE OF THE SIEGE-HOWITZER. 497 
 
 allel, against the works leading to the covered way, and 
 against the crowning of the covered way. 
 
 9th. Against craters formed by the explosion of 
 mines, to prevent the enemy from crowning them. 
 
 10th. Against the passage of the ditch. 
 
 11th. Against the breach. 
 
 12th. All cannon on the flanks which remain mounted, 
 fire rapidly grape or canister shot at the moment of 
 assault. 
 
 In the attach The besiegers are much more restricted 
 in the use of case-shot than the besieged. It should be 
 principally employed under the following circumstances, 
 viz. : 
 
 1st. By cannon placed on the flanks of attack when- 
 ever the besieged make a sortie, and come within suita- 
 ble range. 
 
 2d. At night, against the embrasures which have 
 been cannonaded during the day with solid shot, to 
 prevent them from being repaired. 
 
 3d. Against the flanks, during the night. 
 
 4th. Against the breach during the day or night, as 
 soon as completed, to prevent the enemy from erecting 
 means for defending it. 
 
 5th. Against the besieged, if he attempt to pass out 
 through the breach, after the assault has been repelled. 
 
 479. Fire of the siege-howitzer. The siege-howitzer 
 should be employed in the defence, — 
 
 1st. Against an attacking column, when the ground 
 in front of the place affords a shelter against the fire 
 of guns. 
 
 2d. Against the works of the besiegers. Howitzers 
 32 
 
498 EMPLOYMENT OF FIELD-ARTILLERY. 
 
 are placed on the salients to blow up, with shells, the 
 works situated on the prolongations of the capitals. 
 
 3d. Against the batteries in process of construction 
 on the three parallels. 
 
 4th. Against the heads of saps ; this fire should be 
 executed with small charges. 
 
 5th. The counter approaches are armed with how- 
 itzers. 
 
 6th. Against troops opposing sorties, and especially 
 against cavalry. 
 
 7th. Against the enemy's depots, when their position 
 is known, and when they are within effective range. 
 
 8th. Against the enemy's convoys, when they can be 
 reached, and they offer sufficient surface. 
 
 In the attack. Howitzers are employed by besiegers — 
 
 1st. In a bombardment, by day and night. 
 
 2d. During all periods of the siege, when occasion 
 requires. 
 
 3d. In the half-parallels established between the 
 second and third; against the covered- ways and places 
 of arms. The fire is executed with small charges. 
 
 4th. For ricochet fire, in preference to cannon. 
 
 480. Use of fire-baii§. Fire-balls are used by the de- 
 fence — 
 
 1st. Against columns of attack. 
 
 2d. Against the opening of parallels, so soon as it is 
 ascertained that preparations are made for this purpose. 
 
 3d. Against points in the space occupied by the be- 
 siegers, where a remarkable noise may be heard, and 
 there is reason to suspect that it proceeds from prepa- 
 rations for attack. 
 
 4th. Particularly when it is thought that the be- 
 
FIRE OF MORTARS. 499 
 
 siegers are about to move forward from one parallel to 
 another. 
 
 5th. To discover the movements of the enemy after 
 he has repulsed a sortie, and to prevent him, by the fire 
 of the guns of the place, from following too closely in 
 pursuit. 
 
 In attack. As it is for the interest of the besiegers to 
 conduct their operations as silently and unobserved as 
 possible, they will seldom have occasion to use fire-balls. 
 
 481. Fire of mortars. Mortars generally perform a 
 more important part in siege operations than howitzers ; 
 there are times, even, when they play a very decided 
 part ; too much care, therefore, cannot be employed to 
 render them effective. 
 
 In the defence. Mortars are employed in the de- 
 fence — 
 
 1st. Concurrently with howitzers, when the shape of 
 the ground in front shelters the enemy from the fire 
 of the guns. 
 
 2d. Against batteries and heads of saps. 
 
 3d. Against places sheltered from the fire of flanking 
 guns. Mortars, and particularly light mortars, can be 
 suitably placed at all points, and without interfering 
 with the establishment of gun and howitzer batteries. 
 
 4th. Against the works of the besiegers generally, 
 and especially against the opening of parallels, and the 
 passage from one parallel to another. 
 
 5th. When the besiegers 7 fire has silenced the fire of 
 the guns, the fire of the mortars continues in full activi- 
 ty, not only in the body of the place, but in the demi- 
 lunes and lateral works. 
 
 6th. In covered batteries, during the entire siege, but 
 
500 EMPLOYMENT OF FIELD- AETILLERY. 
 
 particularly during or after the construction of the third 
 parallel. 
 
 7th. Light mortars should be employed in the coun- 
 ter approaches. 
 
 8th. Against the workmen who are engaged in run- 
 ning the sap up the glacis, for the purpose of crowning 
 the covered way. 
 
 9th. To prevent the construction of counter and 
 breaching batteries. 
 
 10th. To prevent the besiegers from establishing 
 themselves in the craters formed by the mines. 
 
 11th. To drive the besiegers from any exterior work 
 which they have taken. 
 
 12th. To prevent the passage of the ditch, or render 
 it difficult. 
 
 13th. To prevent the besiegers from effecting a lodg- 
 ment in the breach, by firing from the interior retrench- 
 ment. 
 
 In the attack. It is very difficult to specify all the 
 circumstances which should govern the besiegers in car- 
 rying on a bombardment, since they depend on a variety 
 of causes ; the following, however, may be enumerated : 
 
 1st. In a regular attack, mortars are the first to open 
 fire, which should be kept up night and day whenever 
 a result can be obtained. 
 
 2d. Heavy, and sometimes medium-sized, mortars, can 
 be employed to retard the enemy's works on the front 
 of attack, the armament of his batteries, the transporta- 
 tion of his cannon, and to shower shells upon the places 
 where his troops assemble, and to burn his principal 
 buildings, etc. Light mortars are rarely used for these 
 purposes, in consequence of the distance of the object 
 
MORTAR CASE-SHOT. 501 
 
 and the lightness of the shells, which have little force 
 of percussion. 
 
 3d. Mortars are employed to throw shells over the 
 entire surface of the ramparts of the front of attack ; 
 and, for this purpose, the fire should be taken in the 
 direction of their length. 
 
 4th. They are also employed against the lateral works 
 as soon as the enemy seeks to establish his guns there 
 for the purpose of retarding the works of attack. 
 
 5th. The curved or mortar fire of the second parallel 
 is as efficient as that of the first parallel, at all periods 
 of the siege. Light mortars here begin to be usefully 
 employed. 
 
 6th. Light mortars are also used with great advan- 
 tage in the half-parallels. From this period of the 
 siege, the covered- way and places of arms are showered 
 with shells. 
 
 7th. From the period of the third parallel, the ene- 
 my's flanks are plied with mortar shells, to support the 
 fire of the counter batteries. 
 
 8th. As soon as the covered-way is crowned, and sub- 
 sequently, when a lodgment in the breach shall have 
 been effected, Coehorn mortars are employed against 
 the enemy, who has withdrawn to the interior retrench- 
 ment of the bastion. 
 
 482. Mortar case-shot, &c. Stones and case-shot from 
 mortars, should be thrown by the defence as soon as the 
 besiegers pass to the construction of the third parallel, 
 and the batteries pertaining to it. This should be con- 
 tinued during the crowning of the covered-way, and 
 during the assault. 
 
 The besiegers, on the contrary, employ these projec- 
 
502 EMPLOYMENT OF SEA-COAST ARTILLERY. 
 
 tiles in all the batteries of the third parallel, and, by 
 this means, seek to drive the enemy from the covered- 
 way and places of arms, thus preparing the way for the 
 assault. 
 
 EMPLOYMENT OF SEA-COAST CANNON. 
 
 483. Nature of. Artillery plays a very important 
 part in sea-coast defence, particularly, since much of it 
 is composed of pieces of sufficient power to disable a 
 wooden vessel by a single well-directed shot. 
 
 The principal advantages which sea-coast cannon pos- 
 sess over those mounted on ship-board, arise from — 
 
 1st. The greater strength and stability of the foun- 
 dations on which they rest. Hence they are made of 
 the largest calibre, and have perfect steadiness of aim 
 in firing. 
 
 2d. The superior resistance of the covering materials 
 of land-batteries. 
 
 Hot-shot and shells are particularly effective against 
 timber, but they have very little effect on earth, or good 
 masonry. 
 
 3d. Less extent of vulnerable surface. The vulner- 
 able surface of a casemate battery comprises that of the 
 embrasures ; that of a barbette battery is composed of 
 those portions of the guns, carriages, and men which are 
 seen above the crest of the parapet — forming, altogether, 
 a narrow belt, not much exceeding two feet in width ; 
 whereas, the entire surface of a vessel, above the water- 
 line, is liable to be seriously injured by projectiles. 
 
 4th. Superior height, or command over the surface of 
 the water. The crest of a land-battery is, at least, 45 
 feet above the surface of the water ; this superiority of 
 
Of THE 
 
 UNIVERSITY 
 
 position gives not only a greater range to the artillery, 
 but it gives it a destructive plunging fire on the decks 
 of the opposing vessels, and, at the same time, places 
 the battery beyond the reach of ricochet fire. 
 
 5th. Greater vertical and horizontal fields of fire. 
 This advantage not only gives greater range to the pro- 
 jectile, but permits the same number of pieces to be 
 brought to bear on a greater number of points. 
 
 484. Armament. The armament of sea-coast bat- 
 teries depends on their importance, and on the depth 
 and width of the channel to be defended. 
 
 The present sea-coast armament comprises the 32 and 
 42 pounder guns for throwing solid shot, hot-shot, shells, 
 and case-shot ; the 8-inch sea-coast howitzer for throw- 
 ing shells and case-shot ; the 8, 10, and 15-inch colum- 
 biads for throwing shot and shells; and the 24-pounder 
 howitzer for throwing single or double shotted canister, 
 in the defence of ditches ; in addition to these, every 
 sea-coast battery should be provided with a certain num- 
 ber of field-pieces, principally howitzers, to prevent a 
 landing, or to act, in close engagements, against the rig- 
 ging and boats of vessels. 
 
 Every battery should be provided with permanent 
 or portable furnaces for heating shot. One hour and 
 a quarter is required to heat up a furnace and bring 
 the shot to a red heat, or half an hour to heat the shot 
 if the furnace has been previously heated. 
 
 Hot shot are better suited for protracted than for 
 short engagements. 
 
 485. Fires. Direct, ricochet, and plunging fires are 
 principally employed in sea-coast defence. 
 
 Direct fire should be used when the surface of the 
 
504 EMPLOYMENT OF SEA-COAST ARTILLERY. 
 
 water is rough, and the accuracy of the rebound cannot 
 be depended upon. The accuracy of sea-coast fire is 
 generally greater than that of the field or siege service, 
 for the reasons, that, the distance of the object, though 
 moving, can be readily and accurately determined by 
 its relation to known objects, the effect of shot can be 
 more easily observed on water than on land, and the 
 size of the object is large, and its appearance, generally, 
 well defined. 
 
 In aiming at a vessel with direct fire, the piece should 
 be pointed at the water-line ; for, if the projectile strike 
 the water, it will either penetrate the hull below the 
 water-line, or rebound and strike above it. 
 
 The range of effective direct fire does not much exceed 
 one mile and a quarter; the extreme range of sea-coast 
 mortars is about two and a half miles ; that of the co- 
 lumbiads, about three and a quarter miles, and the heavy 
 rifle-guns about five miles. 
 
 486. Ricochet-fire. The accuracy of ricochet -fire 
 depends on the surface of the water; under favorable 
 circumstances, the larger sea-coast shells have a range of 
 about 3,000 yards in rolling fire ; their penetrating force, 
 however, is very much diminished toward the extrem- 
 ity of this range. 
 
 The fire of mortars, from ship-board, is very uncer- 
 tain, if the surface of the water be much disturbed. 
 This was shown at the bombardment of Fort McHenry 
 by the British, in the War of 1812, and at the bom- 
 bardment of San Juan d'Ulloa by the French. In the 
 latter case, out of 302 shells that were fired at a dis- 
 tance of 2,200 yards, six only struck the fort, while others 
 fell 1,200 yards beyond it. 
 
 r 
 
TABLE ONE. 505 
 
 CHAPTER XIII. 
 TABLES OF MULTIPLIERS. 
 
 B, I, D, V, &c. 
 
 487. Explanation. It would exceed the limits of this 
 work to enter into a discussion of the formulas from 
 which the values of the multipliers used in the equa- 
 tions of motion in air (page 412) are calculated; it will 
 be sufficient to explain how these tables are used in 
 practice. 
 
 The pupil will find this subject, as well as all others 
 relating to Ballistics, ably and fully treated in Didion's 
 Traite de Balistique. 
 
 488. Table 1. Multiplier B. The decimals are car- 
 ried out to three places, which is sufficient for ordinary 
 
 purposes. The values of — are given in the first hori- 
 zontal line, the value of — ' in the first vertical col- 
 
 r 
 
 umn, and the values of the corresponding multipliers 
 are set opposite to them. 
 
 To find the multiplier B for two intermediate values 
 
 of-- and — ' not given in the tables, we seek, in the 
 c r 
 
 absence of the proper numbers, the corresponding values 
 
 of the nearest tabular numbers. We add to these, parts 
 
 proportional to the differences, as though each part were 
 
 to be considered separately. 
 
506 TABLES OF MULTIPLIERS. 
 
 x V 
 
 Example. — Find the value of B for _=0.5755, and ——1.1219, 
 
 c r 
 
 i. e. B (0.5755; 1.1219). Starting with 0.55 in the first horizontal 
 
 column, and 1.10 in the first vertical column, we find -5=1.479; the 
 
 difference between this and the next number of the horizontal line is 
 
 0.054 ; the difference between the same and the next number of the 
 
 vertical column is 0.013. The difference between 0.5755 and 0.55 is 
 
 0.0255, and between 1.1219 and 1.10 is 0.0219. The value of 
 
 B (0.5755; 1.1219)=1.479-f Q - 0255 0.054 + 0,0219 0.013 — 1.479 + 
 v J 0.05 0.05 
 
 0.027 + 0.006 = 1.512. 
 
 Or, for greater convenience, the foregoing may be placed in the fol- 
 lowing form, the differences being written as whole numbers : 
 
 .#(0.5755; 1.1219) — 1.512 
 ^(0.55; 1.10) =1.479 
 
 s« • • - - 
 
 219 
 
 ™13 . . = 6 
 500 
 
 Multiplier, I. The values of /are given in the same 
 table as those of JB; except that it is necessary to com- 
 mence in the lower horizontal line, and subtract from 
 
 V I V\ 
 them the product of — j 1-) i J, by the corresponding 
 
 number of the line called " correction." 
 
 Example.— To find the value of 7(0.5755; 1.1219), take - = 
 
 c 
 
 0.545, which is less than the proposed number by 0.305, and which 
 
 V 
 
 differs by 0.035 from the next number in the table; — '= 1.10 is the 
 * r 
 
 nearest number to 1.1219 in the first vertical column; for these two 
 numbers we have 7=1.771. This number differs from the adjoining 
 horizontal and vertical numbers in the table by 0.066 and 0.022, re- 
 spectively. The value sought is 1.830, as is thus shown: 
 
TABLE FOUK. 507 
 
 7(0.5755; 1.1219)= 1.830 
 
 I (0.545; 1.10) =1.771 
 305 
 
 •66 = 58 
 
 350 
 219 
 
 ^o5 22 = 10 
 
 —1.1219.2.1219.4= —9 
 
 Table 3. Values of U and D. This table is calcula- 
 
 CO 
 
 ted for differences of 0.10 in case of — > in the upper line, 
 
 C 
 
 and for differences of .05 in case of — % For U, the 
 
 x 
 values of - are found in the upper horizontal line, and 
 
 c 
 
 for D, in the lower line. 
 
 Example.— Find the values of U (0.5755 ; 1.1219) and D (0.5755; 
 1.1219). 
 
 D (0.5755; 1.1219) = 1.336 
 D (0.393; 110) = 1.221 
 
 1825 
 
 1920 119 = - 113 
 
 219 
 
 ^00 5 " - 002 
 
 U (0.5755; 1.1219) = !. 707 
 U (0.50; 1.10) = 1.597 
 755 
 
 Toob 138 = - 104 
 
 219 • 
 
 --14 - .006 
 
 We have [7=1.707, and Z> = 1.336. 
 
 Table 4. Values of - B for the calculation of Ranges. 
 
 This table skives the value oi-B for values of - and — '-, 
 & G c r 
 
 for differences of 0.05 and 0.05 ; the unknown quantity 
 
 t • x - V, i <& T* 
 to be determined is - wnen — - and -.#=/>, are given. 
 
 Arrange the calculations as in the preceding cases. 
 Only one of the proportional parts is unknown, and this 
 is determined by the condition, that if it be added to 
 the other proportional part, and to the number in the 
 table, the sum is equal to the required number. 
 
508 TABLES OF MULTIPLIEES. 
 
 V x x 
 
 Examples. — Having ~ =1.1219 and -B, or ^>=0.8729, find -. 
 
 t .'V k 
 
 Starting with —=1.10, and following the horizontal line, we come 
 
 upon 0.8135, the nearest approach to the proposed number, 0.8729. Find 
 
 * x 
 
 the corresponding value of — which is 0.55; the unknown value of — 
 
 surpasses 0.55 by a certain quantity which we shall call A ; following 
 the previous arrangement of the calculation, and observing that the 
 differences of 0.8135 with the adjacent horizontal and vertical tabular 
 numbers are 0.1065 and 0.0071, respectively, and representing by p the 
 result, we have — 
 
 ^(0.55 + A; 1.1219)= 0.8720 
 
 /? (0.55 ; 1.10 ) = 0.8135 
 
 A 
 
 :1065 — .0559 
 
 0.05 
 0.02] 
 
 71 = .0035 
 
 0.0500 
 
 559 
 We have A=— — 0.05 =0.0263 
 
 1065 
 
 - =0.55 + 0.0263 =0.5763 
 
 c 
 
 The proportional part 559 is equal to 8729 — (8135+35Y 
 
 L 
 
 Table 5. Values of r for initial velocities. 
 
 7S 
 
 This table gives the quotient arising from dividing 
 
 V x V 
 
 — ■ by VB f° r values of - and — - ; the quantity to be 
 
 . V 
 
 determined is — -. The method is the same as in the 
 r 
 
 preceding table ; if the value of the quotient q dimin- 
 ishes as - increases, the sign of the difference should be 
 
 G 
 
 changed. 
 
 V, 
 
 Example.— Having - =0.5755, and? = r = 0.9110, find YL 
 c </B~ r ' 
 
TABLES. % 509 
 
 x 
 The vertical column nearest to -=0.5755 is that which corresponds 
 
 to 0.55 ; the number in this column nearest to 0.9110 is 0.9045, which 
 corresponds to 1.10, and the difference between this and the required 
 number is 0.0065 ; the differences with the neighboring numbers to the 
 right and above, are — 0.0162 and 0.0370, respectively. We therefore 
 have, 
 
 #(0.5755; 1.10+A) = 0.9110 
 
 q (0.55; 1.10) =0.9045 
 
 147 
 or A=— -0.05 =0.0199 
 
 V 
 
 and —^=1.10+0.0199 = 1.1199 
 
 r 
 
 The proportional part 147 is equal to 9110 — (9045 — 82), giving 
 
 V 
 
 A = 0.0199, which, added to 1.10 gives — '=1.1199. 
 
510 TABLES. 
 
 Table 1. — Values of B and L 
 
 ,1 - 
 
 B | c 
 
 0.00 
 
 0.05 
 
 0.10 
 
 0.15 
 
 0.20 
 
 0.25 
 
 0.80 
 
 0.85 
 
 0.40 
 
 0.45 
 
 0.50 
 
 
 0.00 
 
 1.000 
 
 1.017 
 
 1 .034 
 
 1.052 
 
 1.070 
 
 1.089 
 
 1.10* 
 
 1.128 
 
 1.148 
 
 1.169 
 
 1.190 
 
 
 0.05 
 
 1.000 
 
 1.018 
 
 1.036 
 
 1.055 
 
 1.074 
 
 1 .098 
 
 1.114 
 
 1.134 
 
 1.156 
 
 1.177 
 
 1.200 
 
 
 0.10 
 
 1.000 
 
 1.019 
 
 1.038 
 
 1.057 
 
 1.077 
 
 1.098 
 
 1.119 
 
 1.141 
 
 1.163 
 
 1.1-6 
 
 1.210 
 
 
 0.15 
 
 1.000 
 
 1.020 
 
 1.039 
 
 1.060 
 
 1.081 
 
 1.103 
 
 1.125 
 
 1.148 
 
 1.171 
 
 1.195 
 
 1 .220 
 
 
 0.20 
 
 1.000 
 
 1.020 
 
 1.041 
 
 1.063 
 
 1.085 
 
 1.107 
 
 1.130 
 
 1.154 
 
 1.179 
 
 1.205 
 
 1.231 
 
 
 0.25 
 
 1.000 
 
 1.021 
 
 1.043 
 
 1.065 
 
 1.088 
 
 1.112 
 
 1.136 
 
 1.161 
 
 1.1871 1-21' 
 
 1.241 
 
 
 0.80 
 
 1.000 
 
 1.022 
 
 1.045 
 
 1.068 
 
 1.0^2 
 
 1.117 
 
 1.142 
 
 1.168 
 
 1.195 
 
 1.223 
 
 1 .252 
 
 
 0.8* 
 
 1.000 
 
 1.023 
 
 1.046 
 
 1.071 
 
 1.096 
 
 1.121 
 
 1.148 
 
 1.175 
 
 1.203 
 
 1.282 
 
 1.262 
 
 
 0.40 
 
 1.000 
 
 1.024 
 
 1.048 
 
 1.078 
 
 1.099 
 
 1.126 
 
 1.1*8 
 
 1.182 
 
 1.2H 
 
 1.241 
 
 1.273 
 
 
 0.45 
 
 1.000 
 
 1.025 
 
 l.o.-.o 
 
 1.076 
 
 1.108 
 
 1.181 
 
 1.159 
 
 1.189 
 
 1.219 
 
 1.251 
 
 1.288 
 
 
 0.50 
 
 1.000 
 
 1.025 
 
 1.058 
 
 1.0. 9 
 
 1.107 
 
 1.185 
 
 1.165 
 
 1.196 
 
 1.227 
 
 1 .260 
 
 1.294 
 
 
 0.55 
 
 1.000 
 
 1.026 
 
 1.058 
 
 1.0*2 
 
 1.110 
 
 1.140 
 
 1.171 
 
 1.203 
 
 1.235 
 
 1.269 
 
 1.805 
 
 U'l . 
 
 0.60 
 
 1.000 
 
 1.027 
 
 1.055 
 
 1 084 
 
 1.114 
 
 1.146 
 
 1.176 
 
 1.209 
 
 1.244 
 
 1.2.9 
 
 1.315 
 
 th- 
 
 0.C5 
 
 1 .000 
 
 1.028 
 
 1.057 
 
 1 C87 
 
 1.118 
 
 1.149 
 
 1.182 
 
 1 .216 
 
 1.25* 
 
 1.288 
 
 1.826 
 
 I 
 
 0.70 
 
 1 .000 
 
 1.029 
 
 1.059 
 
 1.090 
 
 1.122 
 
 1.1M 
 
 1.188 
 
 1.224 
 
 1.260 
 
 1.298 
 
 1.887 
 
 0.75 
 
 1.000 
 
 1.080 
 
 1.060 
 
 1.092 
 
 1.125 
 
 1.159 
 
 1.194 
 
 1.281 
 
 1.268 
 
 1.30S 
 
 1.348 
 
 £ 
 
 0.80 
 
 1 .000 
 
 1.031 
 
 1.062 
 
 1 095 
 
 1.129 
 
 1.164 
 
 1.200 
 
 1.23S 
 
 1.277 
 
 1.817 
 
 1.859 
 
 
 0.85 
 
 1.000 
 
 1 .031 
 
 1.064 
 
 1.098 
 
 1.133 
 
 1.169 
 
 1.206 
 
 1.V45 
 
 1.285 
 
 1.827 
 
 1.870 
 
 
 90 
 
 1.000 
 
 1 .082 
 
 1.066 
 
 1.101 
 
 1.137 
 
 1.173 
 
 1.212 
 
 1.252 
 
 l.kM 
 
 1.387 
 
 1.3S2 
 
 
 0.95 
 
 1.000 
 
 1.038 
 
 1.067 
 
 1.108 
 
 1.140 
 
 1.178 
 
 121- 
 
 1.259 
 
 1.302 
 
 1.846 1.893 
 
 
 1.00 
 
 1.000 
 
 1.034 
 
 1.069 
 
 1.106 
 
 1.144 
 
 1.183 
 
 1.221 
 
 1.266 
 
 1.310 
 
 1.356 
 
 1.404 
 
 
 1.05 
 
 1.000 
 
 1.035 
 
 1.071 
 
 1.109 
 
 1.148 
 
 1.188 
 
 1.230 
 
 1 273 
 
 1.319 
 
 1.366 
 
 1.415 
 
 
 1.10 
 
 1 000 
 
 1.086 
 
 1.073 
 
 1.112 
 
 1.151 
 
 1.198 
 
 1.236 
 
 1.2-1 
 
 1.32S 
 
 1.376 
 
 1.427 
 
 
 1.15 
 
 1.000 
 
 1.037 
 
 1.075 
 
 1.114 
 
 1.155 
 
 1.198 
 
 1 .242 
 
 1.2S> 
 
 1.836 
 
 1 386 
 
 1 .488 
 
 
 1.9 • 
 
 1.000 
 
 1.087 
 
 1.076 
 
 1.117 
 
 1.159 
 
 1 .203 
 
 1.24S 
 
 1.295 
 
 1 .345 
 
 1.396 
 
 1.450 
 
 . 
 
 1.25 
 
 1.000 
 
 1.038 
 
 1.078 
 
 1.120 
 
 1.163 
 
 1.207 
 
 1.254 
 
 1 .303 
 
 1.353 
 
 1.406 
 
 1.461 
 
 For 1 a? 
 
 
 
 
 
 
 
 
 
 
 
 7 1 7 
 
 0.000 
 
 0.033 
 
 0.067 
 
 0.101 
 
 0.134 
 
 0.168 
 
 0.202 
 
 0.236 
 
 0.270 
 
 0.804: 0.388 
 0.001J 0.001 
 
 1 
 rorrtction 
 
 0.000 
 
 0.000 
 
 0.000 
 
 0.000 
 
 0.000 
 
 0.000 
 
 0.000 
 
 0.001 
 
 0.001 
 
 Fo- 
 B 
 
 ■ 
 
 
 
 0.50 
 
 0.55 
 
 0.60 j 0.65 
 
 0.70 
 
 0.75 
 
 0.80 
 
 0.85 
 
 0.90 
 
 0.95 
 
 1.00 
 
 
 I 0.00 
 
 1.190 
 
 1.212 
 
 1.234 
 
 1.257 
 
 1.2*1 
 
 1.805 
 
 1 .330 
 
 1.855 
 
 1.882 
 
 1 .409 
 
 1 .487 
 
 
 0.05 
 
 1.200 
 
 1.223 
 
 1.V47 
 
 1.271 
 
 1.296 
 
 1 .322 
 
 1.84S 
 
 1.875 
 
 1.40 
 
 1.43' 
 
 1.461 
 
 
 0.10 
 
 1.210 
 
 1.284 
 
 1.259 1.285 
 
 1.81' 
 
 l.«89 
 
 1.866 
 
 1 .395 
 
 1 .425 
 
 1 .455 
 
 1.486 
 
 
 0.15 
 
 1.220 
 
 1.246 
 
 1.272! 1/99 
 
 1.827 
 
 1.85« 
 
 1.885 
 
 1.415 
 
 1.447 
 
 1.479 
 
 1.512 
 
 
 0.20 
 
 1 .-281 
 
 1 .25S 
 
 1.2-5 1.814 
 
 1.348 
 
 1 .378 
 
 1.404 
 
 1.436 
 
 1.469 
 
 1.503 
 
 l.ftw 
 
 
 0.25 
 
 1.241 
 
 1.269 
 
 1.298! 1.828 
 
 1 .359 
 
 1 .3!i0 
 
 1.428 
 
 1.457 
 
 1.491 
 
 1.6*1 
 
 1.563 
 
 
 0.80 
 
 1.252 
 
 1.281 
 
 1.811 1.348 
 
 1 .875 
 
 1.408 
 
 1.442 
 
 1.477 
 
 1.514 
 
 1.551 
 
 1.590 
 
 
 0.85 
 
 1.262 
 
 1.293 
 
 1.8.-5 1.357 
 
 1 .391 
 
 1.425 
 
 1.461 
 
 1.499 
 
 1.586 
 
 1.5 6 
 
 1 616 
 
 
 0.40 
 
 1.278 
 
 1.805 
 
 1.833 1.872 
 
 1 .407 
 
 1.448 
 
 1.48 
 
 1.520 
 
 1.559 
 
 1.601 
 
 1.643 
 
 
 0.45 
 
 1.2-3 
 
 1.317 
 
 l.*51 1.8-7 
 
 1.428 
 
 1.461 
 
 1.500 
 
 1.541 
 
 1 .5S8 
 
 1.626 
 
 1.610 
 
 
 0.50 
 
 1.294 
 
 1.829 
 
 1.365 1.402 
 
 1.440 
 
 1.479 
 
 1.520 
 
 i .563 
 
 l.fOt 
 
 1.651 
 
 1.697 
 
 ^k 
 
 ,•0.55 
 
 1 .805 
 
 1.841 
 
 1.878 1.417 
 
 1 .457 
 
 1.498 
 
 1.540 
 
 1.584 
 
 1 630 
 
 1.677 
 
 1.725 
 
 a 1 
 
 0.60 
 
 1.815 
 
 1 .353 
 
 1.8921 1.432 
 
 1 .473 
 
 1.516 
 
 1 .560 
 
 l.i-OB 
 
 1.654 
 
 1.70 
 
 1.753 
 
 u 
 
 0.65 
 
 1 .826 
 
 1 .865 
 
 1.406 1.447 
 
 1.490 
 
 1.585 
 
 1.581 
 
 1.629 
 
 1.678 
 
 1.729 
 
 1.781 
 
 o 
 
 0.70 
 
 1 .387 
 
 1.378 
 
 1.4201 1.468 
 
 1.507 
 
 1 553 
 
 1.601 
 
 1.651 
 
 1.70; 
 
 1.755 
 
 1.810 
 
 
 0.75 
 
 1.34- 
 
 1. 90 
 
 1.433| 1.478 
 
 1.524 
 
 1.572 
 
 1.622 
 
 1.674 
 
 1.7*7 
 
 1.7-2 
 
 1.839 
 
 
 0.80 
 
 1.859 
 
 1.403 
 
 1.4471 1.494 
 
 1.542 
 
 1.591 
 
 1.643 
 
 1.696 
 
 1.751 
 
 1.809 
 
 1.868 
 
 
 0.85 
 
 1.870 
 
 1.415 
 
 1.462 
 
 1.509 
 
 1.559 
 
 1.610 
 
 1.664 
 
 1.719 
 
 1.776 
 
 1 >30 
 
 1.897 
 
 
 90 
 
 1.88 
 
 1 .428 
 
 1.476 
 
 1.525 
 
 1.577 
 
 1 630 
 
 1 6-5 
 
 1.748 
 
 1.802 
 
 1.86< 
 
 1.927 
 
 
 0.95 
 
 1.898 
 
 1.440 
 
 1 .490 
 
 1.541 
 
 1.594 
 
 1.649 
 
 1.706 
 
 1.766 
 
 1.8*1 
 
 1.691 
 
 1.957 
 
 
 1.00 
 
 1.404 
 
 1 .453 
 
 1.504 
 
 1.557 
 
 1.6'2 
 
 1.669 
 
 1.728 
 
 1.7S9 
 
 1.853 
 
 1.919 
 
 1.9-7 
 
 
 1.05 
 
 1 .415 
 
 1.466 
 
 1 .5.9 
 
 1 .574 
 
 1.630 
 
 1.6S8 
 
 1.749 
 
 1.813 
 
 1.879 
 
 1.941 
 
 2.017 
 
 
 ' 1.10 
 
 1.427 
 
 1.479 
 
 1.5=8 
 
 1.590 
 
 1.64H 
 
 1.708 
 
 1.771 
 
 1.881 
 
 1.905 
 
 1.975 
 
 2.048 
 
 
 1.15 
 
 1.488 
 
 1.49^ 
 
 1.548 
 
 1.606 
 
 1.666 
 
 1.728 
 
 1.798 
 
 1.R61 
 
 1.981 
 
 9.004 
 
 2 079 
 
 
 1.20 
 
 1.450 
 
 1 505 
 
 1.563 
 
 1.623 
 
 1.684 
 
 1.749 
 
 1.816 
 
 1 .8S6 
 
 1.958 
 
 8.088 
 
 ¥.111 
 
 
 1.25 
 
 1.461 
 
 1.5IS 
 
 1 578 
 
 1 .639 
 
 1.703 
 
 1.769 
 
 1.838 
 
 1.910 
 
 l.s-65 
 
 2.06.' 
 
 2.142 
 
 For 
 
 0) 
 
 c 
 
 0.83s 
 
 0.372 
 
 407 
 
 0.441 
 
 0.476 
 
 0.511 
 
 0.545 
 
 0.5S0 
 
 0.615 
 
 0.650 
 
 0.685 
 
 Correct 
 
 on 
 
 0.001 
 
 0.002 
 
 0.002 
 
 0.002 
 
 0.003 
 
 0.003 
 
 0.004 
 
 0.004 
 
 0.005 
 
 0.005 
 
 0.006 
 
TABLES. 
 
 511 
 
 Values of B and I. — (Continued?) 
 
 For 
 B 
 
 
 1.00 
 
 ! 1.05 
 
 1.10 
 
 1.15 
 
 1.20 
 
 | 1.25 
 
 1.80 1.85 J 1.40 
 
 ! 
 
 l 
 1.45 ! 1.50 
 
 
 r o.oo 
 
 1.437 
 
 1.465 
 
 1.494 
 
 1.525 
 
 1.556 
 
 1.588 1 .621 1 1.654 
 
 1.689 
 
 1.725: 1.762 
 
 
 0.05 
 
 1.461 
 
 1.492 
 
 1.523 
 
 1.555 
 
 1 1.588 
 
 1.6221 1.657 1.698 
 
 1.730 1.768! 1.808 
 
 
 0.10 
 
 1.486 
 
 1.519 
 
 1.552 
 
 ; 1.586 
 
 ! 1.621 
 
 1.657| 1.6941 1.782 
 
 1.772 
 
 1.812! 1.854 
 
 
 0.15 
 
 1.512 
 
 1.546 
 
 1.581 
 
 1 1.620 
 
 | 1.654 
 
 1.6921 1.782! 1.772 
 
 1.814 
 
 1.857 1.902 
 
 
 0.20 
 
 1.53S 
 
 1.573 
 
 1.610 
 
 1.649 
 
 ' 1.688 
 
 1.T2S 1.770! 1.818 
 
 1.857 
 
 1.908 1950 
 
 
 0.25 
 
 1.56* 
 
 1.601 
 
 1.610 
 
 1.681 
 
 1.722 
 
 1 1.765 1.809| 1.854 
 
 1.901 
 
 1.949! 1.999 
 
 
 0.80 
 
 1.5 
 
 1.629 
 
 1.670 
 
 1.713 
 
 1.757 
 
 1 .802 
 
 1.848 1.896 
 
 1.945 
 
 1.996 
 
 2.049 
 
 
 0.35 
 
 1.M6 
 
 1.658 
 
 1.701 
 
 1.746 
 
 1.792 
 
 1.889 
 
 1.888 1.988 
 
 1.990 
 
 2.044 
 
 2.100 
 
 
 0.40 
 
 1.643 
 
 1.6»7 
 
 1.732 
 
 1.779 
 
 1.827 
 
 1.877 
 
 1.928 1.981 
 
 2.036 
 
 [ 2.098 
 
 2.151 
 
 
 0.45 
 
 1.670 
 
 1.716 
 
 1.763 
 
 1.812 
 
 1.868 
 
 1 .915 
 
 1.969; 2.025 
 
 2.083 
 
 1 2.142 
 
 2.203 
 
 „. 
 
 0.50 
 
 1.'97 
 
 1.745 
 
 1.795 
 
 1.846 
 
 1 899 
 
 1.954 
 
 2.01l! 2.069 
 
 2.129 
 
 2.192 2.256 
 
 M* 
 
 0.55 
 
 1.725 
 
 1.775! 1.827 
 
 1.881 
 
 1.936 
 
 1.998 
 
 2.0 3 2.114 
 
 2.177 
 
 2.242J 2.810 
 
 e 1 
 
 0.60 
 
 1.7.-3 
 
 1.805 1.859 
 
 1.915 
 
 1.973 
 
 2.033 
 
 2.095 2.159 
 
 2.225 
 
 2.293! 2.364 
 
 J- 
 
 0.65 
 
 1.781 
 
 1.836 1.682 
 
 1.950 
 
 2.011 
 
 2.073 
 
 2.138! 2.205 
 
 2.274 
 
 2.345! 2.419 
 
 1 
 
 0.70 
 
 1.810 
 
 1.866! 1.925 
 
 1.986 
 
 2.049 
 
 2.114 
 
 2.182: 2.251 
 
 2.323 
 
 2.398 2.475 
 
 0.75 
 
 1.899 
 
 1.8971 1.958 
 
 2.022 
 
 2.085 
 
 2.155 
 
 2.226 2.29S 
 
 2.373 
 
 2.451 
 
 2.582 
 
 
 0.-0 
 
 1.868 
 
 1.929 ; 1.99; 
 
 2.058 
 
 2.12^ 
 
 2.197 
 
 2.270! 2.846 
 
 2.424 
 
 2.505 
 
 2.589 
 
 
 0.85 
 
 1.897 
 
 1.9 ! 2.026 
 
 2.095 
 
 2.166 
 
 2.239 
 
 2.315^ 2.394 
 
 2.475 
 
 2.560 
 
 2.648 
 
 
 0.90 
 
 1 .927 
 
 [.992 2.061 
 
 2.132 
 
 2.206 
 
 2.2821 2.361! 2.448 
 
 2.527 
 
 2.616 
 
 2.707 
 
 
 0.95 
 
 1.957 
 
 2.1(25 2.096 
 
 2.169 
 
 2.246 
 
 2.325 
 
 2.407 2.492 
 
 2.580 
 
 2.672 
 
 2.766 
 
 
 1.00 
 
 1.987 
 
 2.057| 2.131 
 
 2.207 
 
 2.287 
 
 2.369 
 
 2.454! 2.542 
 
 2.633 
 
 2.726 
 
 2.627 
 
 
 1.05 
 
 2.017 
 
 2.090 2.167 
 
 2.246 
 
 2.32S 
 
 2.413 
 
 2.501] 2.593 
 
 2.687 
 
 2.786 
 
 2.688 
 
 
 1.10 
 
 2. 046 
 
 2.127 
 
 2.203 
 
 2.284 
 
 2.370 
 
 2.458 
 
 2.549! 2.644 
 
 2.742 
 
 2.844 
 
 2.950 
 
 
 1.15 
 
 2.079 
 
 2.157 
 
 2.240 
 
 2.323 
 
 2.412 
 
 2.503 
 
 2.5971 2.695 
 
 2.797 
 
 2.903 
 
 3.018 
 
 
 1.20 
 
 2.111 
 
 2.191 
 
 2.276 
 
 2.863 
 
 2.454 
 
 2.548 
 
 2 646; 2.746 
 
 2.853 
 
 2.963 
 
 8.076 
 
 
 1.25 
 
 2.142 
 
 2.225 
 
 2.313 
 
 2.403 
 
 2.49: 
 
 2.594 
 
 2.696! 2.801 
 
 2.909 
 
 3.028 
 
 8.141 
 
 For 
 I 
 
 X 
 
 c 
 
 0.685 
 
 0.721 
 
 0.756 
 
 0.791 
 
 0.827 
 
 0.863 
 
 0.899 0.934 
 
 0.970 
 
 1.006 
 
 1.043 
 
 Correcti 
 
 r>n ... 
 
 0.006 
 
 0.007 
 
 0.007 
 
 0.00* 
 
 0.009 
 
 0.010 
 
 0.011! 0.015 
 
 0.013 
 
 0.014 
 
 0.015 
 
 For 
 B 
 
 X 
 
 c 
 
 1.50 1.55 
 
 1.60 
 
 1.65 
 
 1.70 
 
 1.75 
 
 1.80 
 
 1.85 
 
 1.90 
 
 1 
 1.95 2.00 
 
 
 0.00 
 
 1.762 1.799 
 
 1.838 
 
 1.878 
 
 1.920 
 
 1.962 
 
 2.00'. 1 2.051 
 
 2.097 
 
 2.145! 2.194 
 
 
 0.05 
 
 t.80" 1.848 
 
 1.890 
 
 1.988 
 
 1.977 
 
 2.022 
 
 2.069 2.117 
 
 2.167 
 
 2.218! 2.271 
 
 
 0.10 
 
 1.654 1.897 
 
 1.942 
 
 1.98- 
 
 2.035 
 
 2.0v 
 
 2.i:-8 
 
 2.165 
 
 2.23> 
 
 2.293! 2.5-49 
 
 
 0.15 
 
 1.902 1.94- 
 
 1.995 
 
 2.044 
 
 2.094 
 
 2.145 
 
 2.199 
 
 2.254 
 
 2."10j 2.*69| 2.429 
 
 
 0.20 
 
 1.950 1.999 
 
 2.049 
 
 2.101 
 
 2.154 
 
 2.209 
 
 2.265 
 
 2.*24 
 
 2.384 2.44i>! 2.511 
 
 
 0.25 
 
 1.999 2.051 
 
 2.104 
 
 2.158 
 
 2.215 
 
 2.27« 
 
 2.833 
 
 2.395 
 
 2.459 
 
 2.525, 2..' 94 
 
 
 0.30 
 
 2.049 2.103 
 
 2.159 
 
 2.217 
 
 2.277 
 
 2.899 
 
 2.402 
 
 2.468 
 
 2.536 
 
 2. '06 2. 676 
 
 
 0.85 
 
 2.100 2.157 
 
 2.216 
 
 2.277 
 
 2.840 
 
 2.405 
 
 2.473 
 
 2.542 
 
 2.614 
 
 2.688 2.7»5 
 
 
 0.40 
 
 2.151 2.211 
 
 2.274 
 
 2.339 
 
 2.405 
 
 2.473 
 
 2.544 
 
 2.617 
 
 2.693 
 
 2.771; 2.652 
 
 
 0.45 
 
 2.203 2.267 
 
 2.8 2 
 
 2.400 
 
 2.470 
 
 2.542 
 
 2.*17 
 
 2.694 
 
 2.774 
 
 2.857! 2.942 
 
 ^U 
 
 0.50 
 
 2.256 2.328 
 
 2.391 
 
 2. 463 
 
 2.536 
 
 2.«lv 
 
 2.691 
 
 2.772 
 
 2., -56 
 
 2.9481 3.083 
 
 0.55 
 
 2.310; 2.3-0 
 
 2.452 
 
 2.526' 
 
 2.604 
 
 2.6*3 
 
 2.766 
 
 2.851 
 
 2.940 
 
 8.081! 8.126 
 
 e 1 
 
 0.60 
 
 2.: 64 2.437 
 
 2.518 
 
 2.i 591 
 
 2.672 
 
 2.75' 
 
 2.842 
 
 2.932 
 
 3.025 
 
 8.121! 3.220 
 
 «- 
 
 0.65 
 
 2.419 2.4'6 
 
 2.575 
 
 2.657 
 
 2.742 
 
 2.629 
 
 2.920 
 
 3.014 
 
 8.111 
 
 x.212 3.816 
 
 o 
 
 0.70 
 
 2.475 2.555 
 
 2.f38 
 
 2.723 
 
 2.812 
 
 2.904 
 
 2.999! 8.097 
 
 3.199 
 
 8.804 8.413 
 
 0.75 
 
 2.682 2.615 
 
 2.702 
 
 2.791 
 
 2.8-4 
 
 2.979 
 
 *. 079 8.181 
 
 8.288 
 
 3.398 6.512 
 
 
 0>0 
 
 2.589 2.676 
 
 2.7'6 
 
 2.860 
 
 2.956 
 
 3.056 
 
 8.160 
 
 8.267 
 
 8.379 
 
 3.494 3.613 
 
 
 0.85 
 
 2. 64S| 2.738 
 
 2.832 
 
 2.929 
 
 8.080 
 
 3.134 
 
 3.242 
 
 8.:54 
 
 8.471 
 
 8.591; 8.715 
 
 
 0.90 
 
 2.707 2.801 
 
 2>98 
 
 8.000 
 
 8.105 
 
 3.218 
 
 8.826 
 
 8.443 
 
 8.564 
 
 3.689! 8.819 
 
 
 0.95 
 
 2.766J 2 864 
 
 2.966 
 
 3.07l| 
 
 3.180 
 
 8.2«'8 
 
 8.411 
 
 8.582 
 
 8.659 
 
 3.790' 3.925 
 
 
 1.00 
 
 2.627 2.928 
 
 3.034 
 
 8.144 
 
 3.257 
 
 8.875 
 
 8.497 
 
 8.623 
 
 8.755 
 
 8.891 
 
 4.082 
 
 
 1.05 
 
 2.88-1 2.998 
 
 H.103 
 
 8.217 
 
 8>85 
 
 3.457 
 
 8.584 
 
 8.716 
 
 8.652 
 
 8.994 
 
 4.141 
 
 
 1.10 
 
 2.950 8.059 
 
 8.173 
 
 8.291 
 
 8.414 
 
 8.541 
 
 *.fi73 
 
 3.809 
 
 3.951 
 
 4.099 
 
 4.251 
 
 
 1.15 
 
 8.013: 3.126 
 
 3.244 
 
 8.8<;7 
 
 8.494 
 
 8. '25 
 
 8.762 
 
 3.904 
 
 4.052 
 
 4.205 
 
 4.P63 
 
 
 1.20 
 
 8.076: 3.194 
 
 8.816 
 
 8.443 
 
 8.575 
 
 8.711 
 
 3.858 
 
 4.000 
 
 4.158 
 
 4.812 
 
 4.477 
 
 . 
 
 1.25 
 
 3.141 3.262 
 
 3.389 
 1.115 
 
 3.520J 
 
 8.657 
 
 8.798 
 
 8.945 
 
 4.098 
 
 4.257 
 
 4.421 
 
 4.592 
 
 1 or 
 
 1 
 
 1 x 
 1 « 
 
 | 
 1.048 1.079 
 
 1.151 
 
 1.188 
 
 1.225 
 
 1.261 
 
 1.298 
 
 1.385 
 
 1.372 
 
 1.409 
 
 Correcti 
 
 • 
 
 on 
 
 0.015 0.017 
 
 0.018 
 
 0.019 
 
 0.021 
 
 0.022 
 
 0.024J 0.025! 0.027 
 
 0.029! 0.081 
 
512 
 
 TABLES. 
 
 Table 3. — Values of U for velocities and D for 
 
 times. 
 
 For 
 U 
 
 X 
 
 e 
 
 j 0.00 
 
 0.10 
 
 0.20 
 
 0.30 : 0.40 
 
 0.50 ! 0.60 
 
 : 0.70 
 
 0.80 ! 0.90 
 
 1.00 
 
 
 0.00 
 
 1.000 
 
 1.051 
 
 1.105 
 
 1.188 1.221 
 
 1.884 1.850 
 
 1.41S 
 
 1.4' 2 1.568 
 
 1.649 
 
 
 0.05 
 
 1.000 
 
 1.054 
 
 1.110 
 
 1.170 1.238 
 
 1.298 1.867 
 
 1.44C 
 
 1.516 1 597 
 
 1.6S1 
 
 
 0.10 
 
 1.000 
 
 1 .056 
 
 1.116! 1.178' 1.244 
 
 1.312 1.88B 
 
 1.461 
 
 1.641 1.625 1.714 
 
 
 0.15 
 
 1.000 
 
 1.068 
 
 1 .121 1 1.1861 1.255 l.:-27i 1.402 
 
 1 ASi 
 
 1.566! 1.654 1.746 
 
 
 0.20 
 
 1.000 
 
 1.062 
 
 1.1261 1.194 1.2' 6 1.341 1.481 
 
 1 509 
 
 1.590! 1.682 1.779 
 
 
 0.25 
 
 1.000 
 
 LOW 
 
 1.132 1.202! 1.277 
 
 1.865 1.4:37 
 
 1 524 
 
 1.61C 
 
 1.71! 
 
 1.811 
 
 
 0.30 
 
 1.000 
 
 1.007 
 
 1.1*7. 
 
 1.210. 1.88") 
 
 l.xeO, 1.455] 1 64E 
 
 l.<39 
 
 1.7 1 
 
 1.843 
 
 
 0.85 
 
 1.000 
 
 1.069 
 
 1.142 
 
 1.219 1.2'.<9 
 
 1.3S3! J .472 1 564 
 
 1.664 
 
 1.767 
 
 1.876 
 
 
 0.40 
 
 1.000 
 
 1.072 
 
 1.147 
 
 1.227, 1.810 
 
 l.»98| 1.490 
 
 1.58. 
 
 1.689 
 
 1 ,79i 
 
 1.90S 
 
 
 0.45 
 
 1.000 
 
 1.074 
 
 1.153 
 
 1.285! 1.821 
 
 1.412 1.507 
 
 1.608 
 
 1.718 
 
 1.824 
 
 1.941 
 
 H- 
 
 0.50 
 
 1.001) 
 
 1.077 
 
 1.158 
 
 1.248 1.889 1.426! 1.525 
 
 1.629 
 
 1.738 
 
 1.858 1.973 
 
 0.55 
 
 1.000 
 
 1.080 
 
 1.163 
 
 1 .251) 1.848 1.4401 1.542 
 
 1.650 
 
 1 .7*9 
 
 1. 881 2.006 
 
 a 1 
 
 0.60 
 
 1.000 
 
 1.0S2 
 
 1.168 
 
 1.269 1.354; 1.454 1.5*0 
 
 1.'71 
 
 1.787 
 
 1.909 2.088 
 
 1 
 
 0.65 
 
 1.000 
 
 1.035 
 
 1.174 
 
 1.867 1.865 1.469 1.577 
 
 1.6 2 
 
 1.612 
 
 l.«8S 2.070 
 
 0.70 
 
 1.000 
 
 1.0S7 
 
 1.179 
 
 1.876 1.376 1.488 1.596 
 
 1.712 
 
 1.836 
 
 1.966 2.103 
 
 0.75 
 
 1.000 
 
 1.0' 
 
 1.184 
 
 1.288! 1.388! 1.497 1.618 
 
 1.7-3 
 
 L.S6J 
 
 1.995 2.185 
 
 
 0.80 
 
 1.000 
 
 1.092 
 
 1.189 
 
 1 .291i 1 ,899j 1.511 1.680 
 
 1 . 7M 
 
 1.886 
 
 2.028 2.1 68 
 
 
 0.85 
 
 1.000 
 
 1.090 
 
 1.196 
 
 1.2991 1.410! 1.525 1.647 
 
 1.775 
 
 l.'lO 
 
 2.051 2.200 
 
 
 0.90 
 
 1.000 
 
 1.097 
 
 1.200 
 
 1.808 1.421! 1.540 1.666 
 
 1.796 
 
 
 2.080 2.283 
 
 
 0.95 
 
 1.000 
 
 1.100 
 
 1.205! 1.P16I 1.432| 1.554 1.682 
 1.210 1.824! 1.443! 1.583! 1.700 
 
 1.817 
 
 1 .969 
 
 2. His 2.265 
 
 
 1.00 
 
 1.000 
 
 1.103 
 
 1/8S 
 
 1.984 
 
 2.187 2.29T 
 
 
 1.05 
 
 1.000 
 
 1.105 
 
 1.216 1.882 L.464 
 
 1.662 1.717 
 
 1.859 
 
 2.00S 
 
 2.165 2.'80 
 
 
 1.10 
 
 1.000 
 
 1.108 
 
 1.221! 1.340 1.468 
 
 1.591 1.785 
 
 1.880 
 
 2.088 
 
 2.194 
 
 2.862 
 
 
 1.15 
 
 1.000 
 
 1.110 
 
 1.226' 1.34s 1.4T6 
 
 1.611 
 
 1.752 
 
 1.901 
 
 2.067 
 
 2.222 
 
 2.8H5 
 
 
 1.20 
 
 1.000 
 
 1 .113 
 
 1.281 
 
 1.868 1.487 
 
 1.625 
 
 1.770 
 
 1.922 
 
 2.0S2 
 
 2.250 
 
 2.427 
 
 
 1.25 
 
 1.000 
 
 1.115 
 
 1.237 
 
 1.864 1.498 
 
 1.629 
 
 1.787 
 
 1.948 
 
 2.107 
 
 2.279 
 
 2.460 
 
 For 
 
 X 
 
 
 
 
 
 
 
 
 
 
 
 
 2> 
 
 c 
 
 0.000 
 
 0.198 
 
 0.398 
 
 0.5S5 
 
 0.775 
 
 0.962 
 
 1.146 
 
 1.827 
 
 1.506 
 
 1.6S3 
 
 1.858 
 
 For 
 U 
 
 X 
 
 c 
 
 1.00 
 
 1.10 
 
 1.20 
 
 1.30 
 
 1.40 
 
 1.50 
 
 1.60 
 
 1.70 
 
 1.80 1 1.90 
 
 2.00 ' 
 
 < 
 
 0.00 
 
 1.649 
 
 1.7*3 
 
 1.822 1.916 2.014' 2.117 
 
 2.226! 2.340 
 
 2.460 2.586 2.718 
 
 
 0.05 
 
 1.681 
 
 1.770 
 
 1.888 1.961 2.064 2.173 
 
 2.287! 2.407 
 
 2.533! 2 665 2.804 
 
 
 0.10 
 
 1.714 
 
 1 807 
 
 1.904! 2.007 2.115 2.229 
 
 2.348! 2.474 
 
 2.606! 2.744 2 890 
 
 
 0.15 
 
 1.746 
 
 1.S43 
 
 1.945J 2.053 2.166; 2.2.85 2.409! 2.541 
 
 2.679 2.S24 2.976 
 
 
 0.20 
 
 1.779 
 
 1.880 
 
 1.987 2.099 2.217J 2.840 2.471 1 2.608 
 
 2.752 2.908 8.068 
 
 
 0.25 
 
 1.811 
 
 1 917 
 
 2.028| 2.144 2.267! 2.896 
 
 2.582 2.675 
 
 2.825 2.982 3.148 
 
 
 0.*0 
 
 1.843 
 
 1.958 
 
 2.069! 2.190 2.31S 8.451 
 
 2.593 2.742 
 
 2 S98 8.061 8.284 
 
 
 0.35 
 
 1,876 
 
 1.990 
 
 '2.110 2.236 2.369, 2.508 
 
 2.655 2.809 
 
 2 971 3.141 ! 3.320 
 
 
 0.40 
 
 1.90S 
 
 2.027! 
 
 2.15l! 2.282 2.419 2.564 
 
 2.716| 2.876 
 
 8.048 8.220 3.406 
 
 
 0.45 
 
 1.941 
 
 2.063! 
 
 2.192; 2.328 2.470 2.620 
 
 2.777 2 943 
 
 8.1161 8.299, 3.492 
 
 ^ . 
 
 0.50 
 
 1.973 
 
 2.100 
 
 2.233; 2.373! 2.5*11 2.676 
 
 2.838 8.010 
 
 8.189 3.379, 3.577 
 
 M* 
 
 0.55 
 
 2.006 
 
 2.187 
 
 2.274 
 
 2.419 2.571; 2.731 
 
 2.800 3.077 
 
 8.262 8.458 3.663 
 
 3 1 
 
 0.60 
 
 2.038 
 
 2.173 
 
 2.315 
 
 2.465 2.622! 2.787 
 
 2.961 3.143 
 
 3.385! 3.537| 3.749 
 
 fe 
 
 0.65 
 
 2.070 
 
 2.210| 
 
 2.357 
 
 2.511 2.673' 2.848 3.022! 3.210 
 
 3.40SJ 8.616 8.886 
 
 1 
 
 0.70 
 
 2.108 
 
 2 247! 
 
 2.398 
 
 2.556 2.723 2.899 8.0*8. 8.877 
 
 3.481 3.696 3 921 
 
 0.75 
 
 2.135 
 
 2.283 
 
 2.439; 2.602 2.774' 2.955 
 
 8.145! 3.344 
 
 8 554 8.775 4.007 
 
 
 0.80 
 
 2.168 
 
 2.320 1 
 
 2.480 
 
 2.648 8.825 3.011 
 
 3.206 3.411 
 
 8.627 8.854 4.093 
 
 
 0.85 
 
 2.200 
 
 2.357 
 
 2.521 
 
 2.694; 2.875 3.066 
 
 8.267! 3. 478 
 
 8.700 8.933 4.179 
 
 
 0.90 
 
 2.233 
 
 2.393 
 
 2.562 
 
 2.740 2.926 3.122 
 
 3.8291 3.545 
 
 8.778 4.013 
 
 4.265 
 
 
 0.95 
 
 2.265 
 
 2.430! 
 
 2.603 
 
 8.786 2.977 3.178 
 
 8.890 3.612 
 
 3. 846 4.092 
 
 4.351 
 
 
 1.00 
 
 2.297 
 
 2.467: 
 
 2.644 
 
 2.831 3.028 3.234 
 
 3.451 3.679 
 
 8.919 4.171 
 
 4.437 
 
 
 1.05 
 
 2.380 
 
 2 503 
 
 2.686 
 
 2.677 3.078 3.290i 8.512 3.746 
 
 3.992' 4.251 4.588 
 
 
 1.10 
 
 2.862 
 
 2.540 
 
 2 726 
 
 2.988 3.129 3.346! 3.574 3.813 
 
 4.065 4.330; 4.608 
 
 
 1.15 
 
 2.395 
 
 2 577 
 
 2.768 
 
 2. 968 3.180 3.402 1 3.635 3.8S0 
 
 4.1: J 8' 4.409| 4.694 
 
 
 1.20 
 
 2.427 
 
 2.613 
 
 2.809 
 
 3.014 8.230 3.4571 3.696 3.947 
 
 4.2111 4.4^9, 4.780 
 
 . 
 
 1.25 
 
 2.460 
 
 2.660 
 
 2>50 
 
 3.060j 3.281; 3.513| 8.75S 4.014 
 
 4.284 4.568! 4.866 
 
 r or 
 D 
 
 X 
 
 c 
 
 1.886 
 
 i 
 2.080 
 
 2.199 
 
 i I ! 
 
 2.369 2.535 2.701 2.864 3.026 
 
 1 1 
 
 3.186 3.344 ; 8.501 
 
TABLES. 
 
 513 
 
 Table 4. — Values of -B for ranges. 
 
 z. I 0.00 
 
 c ! 
 
 0.00 
 0.05 
 0.10 
 0.15 
 0.20 
 0.25 
 0.30 
 0.35 
 0.40 
 0.45 
 0.50 
 0.55 
 0.60 
 0.65 
 0.70 
 0.75 
 0.80 
 0.85 
 0.90 
 0.95 
 1.00 
 1.05 
 1.10 
 1.15 
 1.20 
 1.25 
 
 0.05 
 
 0.10 
 
 0.15 
 
 0.000 
 0.000 
 0.000 
 0.000 
 0.000 
 0.000 
 0.0000 
 0.000 
 0.000 
 0.000 
 0.000 
 0.000 
 0.000 
 0.000 
 0.000 
 0.000 
 0.000 
 0.000 
 0.000 
 0.000 
 0.000 
 0.000 
 0.000 
 0.000 
 0.000 
 0.000 
 
 0508 
 
 0509 
 .0509 0. 
 .0510 0. 
 .05100. 
 .05110. 
 .0511 0. 
 .0511 0. 
 .0512 
 .0512 0. 
 .0513 0. 
 .0513 0. 
 .05140. 
 .0514 0. 
 .0514 0. 
 .0515 0. 
 .0515 0. 
 .0516 0. 
 .0516 0. 
 .0517 0. 
 .0517 0. 
 .0517 0. 
 .0518 0. 
 .0518 0. 
 .0519 0. 
 .0519 0. 
 
 1034 0. 
 1036 0. 
 
 1038 0. 
 
 1039 0. 
 1041 0. 
 1043 0. 
 10450. 
 1046 0. 
 1048 0. 
 1050 0. 
 
 1052 0. 
 
 1053 0. 
 1055 0. 
 1057 0. 
 
 1059 0. 
 
 1060 0. 
 10620. 
 1064 0. 
 
 1066 0. 
 
 1067 0. 
 1069 0. 
 1071 0. 
 1073 0. 
 
 1075 0. 
 
 1076 0. 
 1078 0. 
 
 0.25 
 
 1578 0. 
 15S2 0. 
 1586 0. 
 1590 0. 
 1594 0. 
 1598 0. 
 1602 0. 
 1006 0. 
 1610 0. 
 1614 0. 
 1018 0. 
 1622 0. 
 1626 0. 
 1630,0. 
 1634 0. 
 16380. 
 16430. 
 1647 0. 
 1651 0. 
 1655 0. 
 1659 0. 
 1663 0. 
 1667 0. 
 1671 0. 
 1676 0. 
 16S0 0. 
 
 2140 
 2148 ! 
 2155 !0 
 
 2162 
 21690 
 2177J0 
 2184j0 
 2191:0 
 2199 
 220610 
 2213 
 2221 
 2228 JO. 
 2286 
 2243 
 
 0.35 
 
 0.40 
 
 2250 
 
 2258 
 
 2265 
 
 2273 
 
 2280 
 
 2288 
 
 2295 
 
 2303 
 
 231010 
 
 231810 
 
 232610 
 
 2722 
 2784 
 2745 
 2757 
 2768 10 
 278010 
 2791 
 2803 ;0 
 2815,0 
 282610 
 233S0 
 2850,0 
 2862 
 287410 
 2886! 0, 
 2897 ! 
 2909 ;0, 
 29910, 
 2933 
 29460, 
 2958|0. 
 2970 0. 
 29S2.0. 
 299410. 
 3006! 0. 
 301910. 
 
 3324 
 33410 
 3357 
 3374 
 3391 
 3408 
 3425 
 3443 
 3460 
 3477 
 3494 
 3512 
 3529 
 3547 
 3564 
 808210 
 3600 0, 
 36170 
 3635 0. 
 3653 0. 
 36710, 
 86890. 
 3707 0. 
 3725 0, 
 3743 0, 
 3761,0, 
 
 3947 
 8970 
 3993 
 40170 
 4040 
 4064 
 4088 
 4112 
 4136 
 41600 
 41840 
 4209 
 4233 
 4257 
 4282 
 4307 
 4332 0, 
 4356 
 4381 0. 
 4407 0, 
 4432 0. 
 4457 0, 
 4482 0, 
 4508 0. 
 4533 0, 
 4559 0, 
 
 0.45 
 
 4591 
 4622 
 4654.0 
 4685 
 47160 
 4748 
 4780 
 4812 0. 
 48440. 
 4877 ;0. 
 4909 0. 
 4942 0, 
 4974 0. 
 5007 !0. 
 5040 0. 
 5074 0. 
 5107 0. 
 5140,0. 
 5174 0. 
 5208 0. 
 5242 0. 
 5276 0. 
 53100. 
 5344 0. 
 5379 0. 
 5414|0. 
 
 0.50 
 
 5258 0. 
 0. 
 9 0. 
 .5379:0. 
 .54200. 
 .5461 0. 
 .55030. 
 .5544J0. 
 .558610. 
 .56280. 
 .567010. 
 .57120. 
 .575510. 
 .57970. 
 .584110. 
 .5S84|0. 
 .5927J0. 
 .5971;0. 
 
 .6015:0. 
 
 .60590. 
 .6103 0. 
 .6147 0. 
 .61920. 
 .62370. 
 62S2 0. 
 6327J0. 
 
 5949 
 6000 
 6051 
 6102 
 6154 
 6206 
 6258 
 
 6416 
 6470 
 6523 
 6577 
 6682 
 6686 
 6741 
 
 7020 
 7076 
 7133 
 7191 
 
 7248 
 
 33 
 
514 
 
 TABLES. 
 
 Table 5.- 
 
 V 
 
 -Values of r 
 B 
 
 for initial velocities. 
 
 0.00 I 0.05 
 
 0.10 | 0.15 I 0.2J 0.25 
 
 0.80 
 
 0.35 
 
 0.40 
 
 0.45 
 
 0.50 
 
 0.05 
 0.10 
 0.15 
 0.20 
 0.25 
 0.80 
 0.85 
 0.40 
 0.45 
 0.50 
 0.55 
 0.60 
 0.65 
 0.70 
 75 
 0.80 
 85 
 0.90 
 0.95 
 1.00 
 1.05 
 1.10 
 1.15 
 1.20 
 1.25 
 
 0.0000 
 0.0000 
 0.0000 
 0.0000 
 0.0000 
 0.0000' 
 0.0000 
 0.0000 
 0.0000 
 ii. iii mo 
 0.0000 
 0.0000, 
 0.0000 
 0.0000 
 0.0000 
 0.0000 
 0.0000 
 0.0000 
 (t. Ill II 10 
 
 0.0000 
 0.0000 
 0.0000 
 0.0000 
 0.0000 
 0.0000 
 
 0. 
 
 .04956 
 
 .09908 
 
 .14857 
 
 .19800 
 
 .24739 
 
 .29675 
 
 0.3461 
 
 0.3953 
 
 0.4446 
 
 0.4933 
 
 0.5429 
 
 0.5920 
 
 0.6411 
 
 0.6901 
 
 0.7391 
 
 0.78S0 
 
 0.8370 
 
 0.8857 
 
 0.9347 
 
 0.9884 
 
 1.0322 
 
 1.0809 
 
 1.1295 
 
 1.1781 
 
 1.2267 
 
 0. 
 
 .04913 
 
 .09816 
 
 .14713 
 
 .19601 
 
 .24430 
 
 .29351 
 
 0.3422 
 
 0.3907 
 
 0.4392 
 
 0.4876 
 
 0.08SI 
 
 0.5841 
 
 0.6323 
 
 0.6803 
 
 0.7283 
 
 0.7762 
 
 0.8241 
 
 0.8717 
 
 0.9195 
 
 0.9671 
 
 1.0145 
 
 1.0620 
 
 1.1094 
 
 1.1566 
 
 1.2033 
 
 0. 
 
 .04869 
 .09725 
 .14569 
 .19402 
 .24221 
 .29029 
 0.8888 
 0.3361 
 0.4333 
 0.4815 
 0.5289 
 0.5762 
 0.8988 
 0.6706 
 0.7176 
 • .7645 
 0.8113 
 0.8579 
 0.9045 
 O.9509 
 0.9971 
 1.0434 
 1.0395 
 1.1354 
 1.1813 
 
 0. 
 .04825 
 
 .14426 
 .19204 
 .98968 
 .28710 
 0.3344 
 0.3315 
 '.4235 
 0.4754 
 0.5220 
 0.5635 
 0.6148J 
 0.6610 
 0.7071! 
 0.753" 
 0.7937 
 0.S443 
 0.8397 
 '•.9349 
 0.9801 
 1.0251 
 1.0700 
 1.1146 
 1.1592 
 
 0. 
 
 .04782 
 
 .09543 
 
 .14284 
 
 .19')"7 
 
 .23703 
 
 .23392 
 
 o.33o6 
 
 0.3770 
 
 0.4232 
 
 0.4693 
 
 0.5152 
 
 0.5608; 
 
 0.6063 
 
 0.6516 
 
 0.6967 
 
 0.7416 
 
 0.7363 
 
 0.8309 
 
 0.8752 
 
 0.9194 
 
 0.9634 
 
 1.0072 
 
 I.11SO8 
 
 1.0942 
 
 1.1375 
 
 i. 04738 .04695 
 .09452 .09362 
 .14143 .14001 
 .18311 .13614 
 .23454 .98900 
 23075 .27759 
 0.8987 .3229 
 0.3725 0.3650 
 0.4180 0.4198 
 0.4633 0.4573 
 0.5084 0.5016 
 0.5532 J 0.5456 
 0.5978 0.5894 
 0.6422 1.6329 
 0.6864 0.6761 
 0.7303 0.7191 
 0.7741 0.7619 
 0.8176 0.8044 
 0.8609 jo. 8467 
 0.9U40 0.8887 
 0.9469 0.9305 
 0.9895 0.9720 
 1. 0881 > II. 0184 i 
 1.0741 1.0543 
 1.1162 1.1952 
 
 0. 
 
 .04651 
 .09271 
 .13860 
 .13418 
 .99949 
 .27444 
 0.3191 
 0.8035 
 0.4O75 
 .4513 
 0.4948 
 '.5380 
 1.6810 
 0.6236 
 0.6659 
 0.7080 
 .7498 
 0.7913 
 0.8327 
 0.8780 
 0.9148 
 0.9547 
 0.9! 149 
 1.0848 
 1.0745 
 
 .04564 
 ,'9<91 
 .13778 
 .18023 
 .22440 
 .26818 
 0.8116 
 3546 
 0.8973 
 0.4396 
 I.4S15 
 0.5231 
 0.5645 
 0.6053 
 0.6459 
 0.6862 
 0.7261 
 0.7784; 0.7657 
 0.81880.8051 
 0.8587 0.8489 
 .8984 0.8826 
 O.9377 0.921O 
 0.97680.9590 
 1.0156 0.9967 
 1.0541 l.« 841 
 
 .09181 
 .18719 
 .15223 
 .22692 
 .27180 
 0.3153 
 O.3590 
 0.4024 
 0.4454 
 0.4881 
 0.5305 
 -.5727 
 0.6144 
 0.6558 
 0.6971 
 0.7379 
 
 0.50 
 
 I 0.55 
 
 0.60 
 
 0.05 
 0.10 
 0.15 
 0.20 
 0.25 
 0.30 
 0.35 
 0.40 
 0.45 
 
 0.65 
 0.70 
 0.75 
 0.80 
 0.S5 
 90 
 0.-3. 
 l.i'O 
 1.05 
 1.10 
 
 1.15 
 1.20 
 1.25 
 
 ;o. 0. 
 
 1 .04564 .04521 
 1 .09091 .09001 
 j. 13778 .13438 
 .18 '28 .17835 
 I .22440 .22190 
 1. 26818 '. 26507 
 !". 3116 0.8078 
 ! 1. 3546 0.85 >2 
 ;".8973 0.3922 
 10.4396 0.4338 
 JO 4815 0.4750: 
 10.5231 0.5158' 
 0.5645 0.5563 
 io. 6053 0.5964 
 i 0.6459 0.6361 
 i 0.6362 0.6755, 
 10.7261 0.7145 
 0.7657 m. 7532 
 0.8051 .7916 
 0.8439 0.8295 
 0.8326 .8671 
 0.921-0.9 45 
 0.9590 0.9415 
 0.9967 0.9781 
 i 1.0341 1.0145 
 I 1 
 
 0. 
 
 .04478 
 
 .08911 
 
 .13299 
 
 .17643 
 
 .21942 
 
 0.65 
 
 0.3041 
 0.8458 
 0.3871 
 
 0.4280 
 0.4835 
 O.50S6 
 0.54S3 
 0.5875 
 0.8264 
 0.6650 
 0.7031 
 0.7409 
 0.7783 
 0.8153 
 0.8520 
 0.8883 
 0.9243 
 0.9599 
 0.9953 
 
 0. 
 
 .('4435 
 .08821 
 .18160 
 .17451 
 .21694 
 .25S90 
 0.8 04 
 '.8415 
 0.8821 
 0.4223 
 0.4621 
 0.5014 
 • ».5403 
 0.5788 1 
 0.6169 
 0.6546 
 0.6919 
 0.7288 
 0.7652 
 0.8014 
 0.8871 
 0.8725 
 ".9 75 
 0.9421 
 0.9764 
 
 0.70 I 0.75 
 
 04392 
 .08732 
 .18 21 
 .17259 
 .21448 
 .25583 
 0.2963 
 0.3372 
 ".8772 
 0.4167 
 0.4557 
 '.4943 
 0.5325 
 
 .57 2 
 0.6"75 
 -.6443 
 0.6308 
 0.7168 
 0.7524 
 '.7876 
 0.8225 
 0.8570 
 O.8909 
 0.9246 
 0.9579 
 
 0. 
 
 .04349 
 
 .08644 
 
 .128&3 
 
 .17069 
 
 .21203 
 
 .25235 
 
 0.2932 
 
 0.3*30 
 
 0.8723 
 
 0.4111 
 
 0.4494 
 
 0.4873 
 
 0.5247 
 
 0.5616 
 
 0.59S1 
 
 0.6342 
 
 0.6698 
 
 0.7 00 
 
 0.739S 
 
 ".7741 
 
 0.8081 
 
 0.8417 
 
 0.8747 
 
 0.9075 
 
 0.9398 
 
 0.89 
 
 0.S5 I 0.90 
 
 0.95 
 
 0. 
 
 .04263 
 
 .08466 
 
 ,12608 
 
 .16091 
 
 .20715 
 
 .94892 
 
 0.2S59 
 
 0. 
 
 .04306 
 .08555 
 .12746 
 .16880 
 .20958 
 .24983 
 |0.2S95, .. 
 '0.32S7 0.8946 
 I ".8674 1 0.3625 
 '0.4055 O.4000 
 0.44890.4870 
 0.4804 0.4735 
 '0.5170 0.5093 
 0.5532 0.5448 
 I ".5889 0.5793 
 0.0242 0.6143 
 0.6588 0.6432 
 10. 6934J 0.6819 
 o.7273!o.7149 
 I 0.7608 ".7476 
 0.7939 0.7798 
 0.8265". 8116 
 0.85880.8430 
 0.8906 0.8739 
 0.9990 0.9046 
 
 0. 0. 
 .04221 .04178 
 .08878 .08289 
 .12471 .12334 
 .16503 .16315 
 .20478 .20233 
 .24888 .94087 
 0.9894|0.9788 
 0.8203 0.3162 
 0.3577 0.8529 
 ".89450.8891 
 0.4308 0.4247 
 0.4666 0.4598 
 0.5018 0.4944 
 0.6865.0.6284 
 .5708 0.6619 
 0.6045 0.5949 
 0.68770.6278 
 0.6706 0.6594 
 0.702S 0.6909 
 0.7341 0.7219 
 0.7660 0.7525 
 
 0.2753 
 0.3121 
 0.34S2 
 0.3833 
 0.4187 
 0.4531 
 0.4870 
 0.5203 
 0.5531 
 0.5854 
 0.6171 
 0.6484 
 0.6792 
 0.7094 
 .7393 
 0.7970 0.7897 0.7688 
 0.8275 0.81 24; 0.7975 
 0.8576 8416 0.8260 
 0.S873 0.8705 0.8540 
 
 1.00 
 
 .04136 
 
 .08202 
 .12198 
 .16128 
 ,19994 
 
TABLE FOR BALLISTIC MACHINE. 
 
 515 
 
 Table of Times, calculated for the West Point Ballistic 
 Machine. 
 
 2*1 
 
 L ngth of simple pendulum, 5.769 in.; and ; =0.001509' 
 
 360y2gl 
 
 
 Time of 
 
 
 
 Time of 
 
 1 
 
 Degrees. 
 
 passage for 
 each degree. 
 
 Sum of Times. 
 
 Degrees 
 
 passage for 
 1 each degree. 
 
 Sum of Times. 
 
 1 
 
 .00151 
 
 ' 
 
 26 
 
 .01)159 
 
 .03987 
 
 2 
 
 .00151 
 
 .00302 
 
 27 
 
 .00159 
 
 .04146 
 
 3 
 
 .00151 
 
 .00453 
 
 28 
 
 .00160 
 
 .04306 
 
 4 
 
 .00151 
 
 .00604 
 
 29 
 
 .00161 
 
 .04467 
 
 5 
 
 .00151 
 
 .00755 
 
 30 
 
 .00162 
 
 .04629 
 
 6 
 
 .00151 
 
 .00906 
 
 31 
 
 .00163 
 
 .04792 
 
 7 
 
 .00151 
 
 .01057 
 
 32 
 
 .00163 
 
 .04955 
 
 8 
 
 .00151 
 
 .01208 
 
 33 
 
 .00164 
 
 .05119 
 
 9 
 
 .00151 
 
 .01359 
 
 34 
 
 .00165 
 
 .05284 
 
 10 
 
 .00152 
 
 .01511 
 
 35 
 
 .00166 
 
 .05450 
 
 11 
 
 .00152 
 
 .01663 
 
 36 
 
 .00167 
 
 .05617 
 
 12 
 
 .00152 
 
 .01815 
 
 37 
 
 .00168 
 
 .05785 
 
 13 
 
 .00152 
 
 .01967 
 
 38 
 
 .00170 
 
 .05955 
 
 14 
 
 .00153 
 
 .02120 
 
 39 
 
 .00171 
 
 .06126 
 
 15 
 
 .00153 
 
 .02273 
 
 40 
 
 .00172 
 
 .06298 
 
 16 
 
 .00153 
 
 .02426 
 
 41 
 
 .00173 
 
 .06471 
 
 17 
 
 .00154 
 
 .02580 
 
 42 
 
 .00175 
 
 .06646 
 
 18 
 
 .00154 
 
 .02734 
 
 43 
 
 .00176 
 
 .06822 
 
 19 
 
 .00155 
 
 .02889 
 
 44 
 
 .00178 
 
 .07000 
 
 20 
 
 .00155 
 
 . 03044 
 
 45 
 
 .00179 
 
 .07179 
 
 21 
 
 .00156 
 
 .03200 
 
 46 
 
 .00181 
 
 .07360 
 
 22 
 
 .00156 
 
 .03356 
 
 47 
 
 .00182 
 
 .07542 
 
 23 
 
 .00157 
 
 .03513 
 
 48 
 
 .00184 
 
 .07726 
 
 24 
 
 .00157 
 
 .03670 
 
 49 
 
 .00186 
 
 .07912 
 
 25 
 
 .00158 
 
 .03828 
 
 50 
 
 .00188 
 
 .08100 
 
 Example. — What is the velocity of a projectile when the time of 
 its passage between two targets, 100 feet apart, corresponds to 20.5 
 degrees of the graduated arc ? 
 
 Time of 20 D : 
 Add for 0.5° 
 
 Time of 20° .5 
 
 0.03044 
 0.00077 
 
 0.03121 
 2 
 
 Log. of 100 = 2.000000 
 Log. 0.06242 ~ 2.795324 
 
 Log. 1602. = 3.204676 
 
 Double arc s 0.06242 
 
 Velocity ss 1602. feet. 
 
516 
 
 TABLES OF FIRE. 
 
 4 
 
 TABLES OF FIRE 
 
 RANGES. 
 
 The range of a shot or shell is the first graze of the ball on horizontal ground, 
 the piece being mounted on its appropriate carriage. 
 
 The range of a spherical case-shot is the distance at which the shot bursts 
 near the ground, in the time given ; thus showing the elevation and the length 
 of fuse required for certain distances. 
 
 Kind of Ordnance. 
 
 Powder. 
 
 Ball. 
 
 Eleva- 
 tion. 
 
 Range. 
 
 Remarks. 
 
 
 Lbs. 
 
 
 o / 
 
 Yards. 
 
 
 6-PDR. FIELD GUN. 
 
 1.25 
 
 Shot. 
 
 
 
 1 
 
 2 
 3 
 4 
 5 
 
 318 
 674 
 
 867 
 1138 
 1256 
 1523 
 
 
 
 1.25 
 
 Sph. case 
 
 1 
 
 600 
 
 Time, 2 seconds. 
 
 
 
 shot. 
 
 1 45 
 
 700 
 
 <• H » 
 
 
 
 
 2 
 
 800 
 
 i, 3 u 
 
 
 
 
 2 45 
 
 900 
 
 , H , 
 
 
 
 
 3 
 
 1000 
 
 u 3f , 
 
 
 
 
 3 15 
 
 1100 
 
 " 4 . « 
 
 
 
 
 4 
 
 1200 
 
 u 5 
 
 12-PDR. FIELD GUN, 
 
 2.5 
 
 Shot. 
 
 
 
 347 
 
 
 Model 1841. 
 
 
 « 
 
 1 
 
 1 30 
 2 
 3 
 
 4 
 5 
 
 662 
 
 785 
 
 909 
 
 1269 
 
 1455 
 
 1663 
 
 
 
 2.5 
 
 Sph. case 
 
 1 
 
 6U0 
 
 Time, If seconds. 
 
 
 
 shot. 
 
 1 45 
 
 700 
 
 " 2i " 
 
 
 
 
 2 
 
 800 
 
 « 21 u 
 
 
 
 
 2 15 
 
 900 
 
 u 3 
 
 
 
 
 2 30 
 
 1000 
 
 M H U 
 
 
 
 
 3 
 
 1100 
 
 « 4 
 
 
 • 
 
 
 3 30 
 
 1200 
 
 " 4^ « 
 
TABLES OF FIRE. 
 Ranges — Continued. 
 
 517 
 
 Kind ov Ordnance. 
 
 Powder. 
 
 Ball. 
 
 Eleva- 
 tion. 
 
 Eange. Eemarks. 
 
 
 Lbs. 
 
 
 c / 
 
 Yards. 
 
 
 12-PDR FIELD GUN, 
 
 2.5 
 
 Shot. 
 
 
 
 325 
 
 
 Model 1857. 
 
 
 i. 
 
 1 
 2 
 3 
 4 
 
 620 
 
 875 
 1200 
 1320 
 
 
 
 
 ii 
 
 5 
 
 1680 
 
 1 
 
 
 
 2.5 
 
 Sph. case 
 
 30 
 
 II 
 300 Time, 1 second. 
 
 
 
 shot. 
 
 1 
 
 575 ' 
 
 " 1| « 
 
 
 
 " 
 
 1 30 
 
 633 
 
 " 2| " 
 
 
 
 ii 
 
 2 
 
 730 
 
 it 3 ii 
 
 
 
 " 
 
 3 
 
 960 1 " 4 " 
 
 
 
 M 
 
 3 30 
 
 1080 1 " 4f " 
 
 
 
 " 
 
 3 45 
 
 1135 
 
 II 5 M 
 
 
 2.0 
 
 Shell. 
 
 
 
 300 
 
 u £ U 
 
 
 
 " 
 
 30 
 
 425 
 
 „ ^ u 
 
 
 
 ii 
 
 1 
 
 616 
 
 u !| ii 
 
 
 
 u 
 
 1 30 
 
 700 
 
 ii ^ ii 
 
 
 
 " 
 
 2 
 
 787 
 
 '• 2f « 
 
 
 
 " 
 
 2 30 
 
 925 ! 
 
 " 3i " 
 
 
 
 " 
 
 3 
 
 1080 
 
 M 4 II 
 
 
 
 II 
 
 3 45 
 
 1300 
 
 ii jj ii 
 
 12-PDR. FIELD HOW- 
 
 1.0 
 
 Shell. 
 
 
 
 195 
 
 
 ITZER. 
 
 
 II 
 
 1 
 o 
 
 3 
 
 4 
 5 
 
 539 
 640 
 847 
 975 
 1072 
 
 
 
 0.75 
 
 Sph. case 
 
 2 15 
 
 485 
 
 Time, 2 seconds. 
 
 
 
 shot. 
 
 3 15 
 
 715 
 
 i. 3 
 
 
 
 it 
 
 3 45 
 
 1050 
 
 « 4 
 
 12-PDR. MOUNTAIN 
 
 0.5 
 
 Shell. 
 
 
 
 170 
 
 
 HOWITZER. 
 
 
 ii 
 
 1 
 2 
 
 300 
 392 
 
 
 
 
 " 
 
 2 30 
 
 500 
 
 Time, 2 seconds. 
 
 
 
 II 
 
 3 
 
 637 
 
 
 
 
 " 
 
 4 
 
 785 
 
 ii 3 i| 
 
 
 
 II 
 
 5 
 
 1005 
 
 
 
 0.5 
 
 Sph. case 
 
 
 
 150 
 
 
 
 
 shot. 
 
 2 30 
 
 450 
 
 Time, 2 seconds. 
 
518 
 
 TABLES OF FIRE. 
 Ranges — Continued. 
 
 Kind of Ordnance. 
 
 Powder. 
 
 Ball. 
 
 Eleva- 
 tion. 
 
 Eange. 
 
 Remarks. 
 
 
 Lbs. 
 
 
 o / 
 
 Yards. 
 
 
 12-PDR. MOUNTAIN 
 
 0.5 
 
 Sph. case 
 
 3 
 
 500 
 
 
 howitzer — Con- 
 
 
 shot. 
 
 4 
 
 700 
 
 Time, 2£- seconds. 
 
 tinued. 
 
 
 
 4 30 
 
 800 
 
 ii 3 ii 
 
 24-PDR. FIELD HOW- 
 
 2.0 
 
 Shell. 
 
 
 
 295 
 
 
 ITZER. 
 
 
 it 
 
 1 
 
 516 
 
 
 
 
 u 
 
 2 
 3 
 
 193 
 976 
 
 
 
 
 u 
 
 4 
 
 1272 
 
 
 
 
 u 
 
 5 
 
 1322 
 
 
 
 2.5 
 
 Sph. case 
 
 1 30 
 
 600 
 
 Time, 2 seconds. 
 
 
 
 shot. 
 
 2 
 
 700 
 
 ,1 2i u 
 
 
 
 M 
 
 2 30 
 
 800 
 
 II 3 £ M 
 
 
 » 
 
 M 
 
 2 45 
 
 900 
 
 " 3* " 
 
 
 
 (( 
 
 3 15 
 
 1000 
 
 u 4 
 
 
 
 H 
 
 3 45 
 
 1100 
 
 „ 4 ^ N 
 
 
 
 (( 
 
 3 50 
 
 1200 
 
 M 4| u 
 
 32-PDR. FIELD HOW- 
 
 2.5 
 
 Shell. 
 
 
 
 290 
 
 
 ITZER. 
 
 
 II 
 
 1 
 
 53 L 
 
 
 
 
 M 
 
 2 
 
 779 
 
 
 
 
 <t 
 
 3 
 
 1029 
 
 
 
 
 M 
 
 4 
 
 1203 
 
 
 
 
 M 
 
 5 
 
 1504 
 
 
 
 3.25 
 
 Sph. case 
 
 1 30 
 
 600 
 
 Time, 2 seconds. 
 
 
 
 shot. 
 
 2 
 
 700 
 
 m 2i " 
 
 
 
 m 
 
 2 15 
 
 800 
 
 u 3 
 
 
 
 M 
 
 2 45 
 
 900 
 
 " 3£ " 
 
 
 
 " 
 
 3 
 
 1000 
 
 II 3 j M 
 
 
 
 (( 
 
 3 35 
 
 1100 
 
 « 4± " 
 
 
 
 (( 
 
 3 45 
 
 1200 
 
 u 4 | u 
 
 18-PDR. SIEGE AND 
 
 4.5 
 
 Shot. 
 
 1 
 
 641 
 
 
 GARRISON GUN. 
 
 
 " 
 
 2 
 
 950 
 
 
 On barbette carriage. 
 
 
 u 
 
 u 
 
 3 
 
 4 
 5 
 
 1256 
 1450 
 1592 
 
 
 24-PDR. SIEGE AND 
 
 6.0 
 
 Shot. 
 
 
 
 412 
 
 
 GARRISON GUN. 
 
 
 ii 
 
 1 
 
 842 
 
 
 On siege carriage. 
 
 
 « 
 
 1 30 
 
 953 
 
 
 
 
 H 
 
 2 
 
 1147 
 
 
 
 
 11 
 U 
 
 3 
 
 4 
 
 1417 
 1666 
 
 
 
 
 ii 
 
 5 
 
 1901 
 
 
TABLES OF FIRE. 
 Ranges — Continued. 
 
 519 
 
 Kind of Okdnance. 
 
 Powder. 
 
 Ball. 
 
 Eleva- 
 tion. 
 
 Range. 
 
 Remarks. 
 
 
 Lbs. 
 
 
 o / 
 
 Yards. 
 
 
 32-PDR. SEA-COAST 
 
 6.0 
 
 Shot. 
 
 1 45 
 
 900 
 
 
 GUN. 
 
 8.0 
 
 
 1 
 
 713 
 
 
 On barbette carriage. 
 
 
 
 1 30 
 
 1 35 
 
 2 
 
 3 
 
 4 
 
 5 
 
 800 
 900 
 1100 
 1433 
 1684 
 1922 
 
 
 42-PDR, SEA-COAST 
 
 10.5 
 
 Shot. 
 
 1 
 
 775 
 
 
 GUN. 
 
 
 u 
 
 2 
 
 1010 
 
 
 On barbette carriage. 
 
 
 u 
 
 3 
 
 4 
 5 
 
 1300 
 1600 
 1955 
 
 
 8-INCH SIEGE HOW- 
 
 4.0 
 
 Shell, 
 
 
 
 251 
 
 
 ITZER. 
 
 
 45 lbs. 
 
 1 
 
 435 
 
 
 On siege carriage. 
 
 
 
 2 
 3 
 4 
 5 
 12 30 
 
 618 
 
 720 
 
 992 
 
 1241 
 
 2280 
 
 
 8-INCH SEA-COAST 
 
 4.0 
 
 Shell, 
 
 1 
 
 405 
 
 
 HOWITZER, 
 
 
 45 lbs. 
 
 2 
 
 652 
 
 
 On barbette carriage. 
 
 
 
 3 
 4 
 5 
 
 875 
 1110 
 1300 
 
 
 
 6.0 
 
 
 1 
 2 
 3 
 4 
 5 
 
 572 
 
 828 
 
 947 
 
 1168 
 
 1463 
 
 
 
 8.0 
 
 
 1 
 2 
 3 
 4 
 5 
 
 646 
 
 909 
 
 1190 
 
 1532 
 
 1800 
 
 
 10-INCH SEA-COAST 
 
 12.0 
 
 Shell, 
 
 1 
 
 580 
 
 
 HOWITZER. 
 
 
 90 lbs. 
 
 2 
 
 891 
 
 Time, 3 seconds. 
 
 On barbette carriage. 
 
 
 M 
 
 3 
 3 30 
 
 1185 
 1300 
 
 " 4 " 
 
 
 
 ti 
 
 4 
 
 1426 
 
 M - 5i u 
 
 
 
 II 
 
 5 
 
 1650 
 
 u 6 
 
520 
 
 TABLES OF FIRE. 
 
 Ranges — Continued. 
 
 Kind of Ordnance. 
 
 Fowder. 
 
 Ball. 
 
 Eleva- 
 tion. 
 
 Range. 
 
 Remarks. 
 
 
 Lbs. 
 
 
 o ' 
 
 Yards. 
 
 
 8-IN. COLUMBIAD.* 
 
 10.U 
 
 Shell, 
 
 1 
 
 081 
 
 Time, 1.88 seconds. 
 
 
 
 50 lbs. 
 
 2 
 
 1108 
 
 " 3.58 " 
 
 
 
 " , 
 
 3 
 
 1400 
 
 " 4.30 
 
 
 
 " 
 
 4 
 
 1649 
 
 " 5.41 
 
 
 
 u 
 
 5 
 
 1733 
 
 " 6.25 
 
 
 
 u 
 
 G 
 
 1994 
 
 " 7.56 
 
 
 
 " 
 
 7 
 
 2061 
 
 " 7.96 
 
 
 
 M 
 
 8 
 
 2250 
 
 " 9.12 
 
 
 
 ii 
 
 9 
 
 2454 
 
 '• 10.16 
 
 
 
 it 
 
 10 
 
 2664 
 
 " 10.91 
 
 
 
 " 
 
 11 
 
 2718 
 
 " 11.3 
 
 
 
 u 
 
 12 
 
 2908 
 
 " 13.0 
 
 i 
 
 
 " 
 
 13 
 
 3060 
 
 " 14.08 
 
 
 
 " 
 
 14 
 
 312:5 
 
 " 14.25 
 
 
 
 " 
 
 15 
 
 3138 
 
 " 16.0 
 
 
 
 " 
 
 20 
 
 3330 
 
 " 18.40 
 
 
 
 ii 
 
 25 
 
 3474 
 
 " 20.0 
 
 
 
 " 
 
 30 
 
 3873 
 
 " 25.0 
 
 
 
 Shot. 
 
 5 
 
 1697 
 
 " 6.20 
 
 
 
 " 
 
 15 
 
 3224 
 
 " 14.19 
 
 10-IN. COLUMBIAD.* 
 
 15.0 
 
 Shell, 
 
 3 
 
 1068 
 
 Time, 3.20 seconds. 
 
 
 
 100 lbs. 
 
 5 
 
 1525 
 
 " 5.64 
 
 
 
 
 < 
 
 8 
 
 -2238 
 
 " 8.10 
 
 
 
 
 1 
 
 10 
 
 2720 
 
 " 10.98 " 
 
 
 
 
 ' 
 
 12 
 
 2847 
 
 " 11.73 " 
 
 
 
 
 ' 
 
 20 
 
 3842 
 
 " 18.92 
 
 
 
 
 4 
 
 30 
 
 4836 
 
 " 27.50 
 
 
 
 SI 
 
 ot, 
 
 15 
 
 3281 
 
 " 14.32 
 
 
 
 125 
 
 lbs. 
 
 30 
 
 5 1 63 
 
 " 27.08 
 
 
 18.0 
 
 
 i 
 
 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 8 
 
 10 
 
 15 
 
 20 
 
 25 
 
 30 
 
 35 
 
 394 
 752 
 1002 
 1230 
 1570 
 1814 
 2037 
 2519 
 "27 77 
 3525 
 4020 
 4304 
 4761 
 5433 
 
 Axis of p-un 1 1 Let 
 above the water. 
 
 Shot ceased to ricochet 
 on water. 
 
 
 20.0 
 
 " 
 
 39 15 
 
 5654 
 
 
 
 12.0 
 
 Shell, 
 
 1 
 
 800 
 
 
 
 
 100 lbs. 
 
 ii 
 
 2 
 3 
 
 1012 
 1184 
 
 
 * Axis of gun 6 fret above the horizontal plane. 
 
TABLES OF FIRE. 
 Ranges — Continued. 
 
 521 
 
 Kind of Ordnance. 
 
 Powder. 
 
 Bull. 
 
 Eleva- 
 tion. 
 
 . 1 
 
 Eange. 
 
 ! 
 
 Iicmarks. 
 
 
 Lbs. 
 
 
 
 
 Yards. 
 
 
 10-IN. COLUMBIAD 
 
 12.0 
 
 Shell, 
 
 4 
 
 1443 
 
 
 Continued. 
 
 
 100 lbs. 
 
 5 
 
 1604 
 
 
 
 18.0 
 
 u 
 M 
 
 tl 
 
 
 1 
 2 
 3 
 4 
 
 448 
 
 747 
 
 1100 
 
 1239 
 
 1611 
 
 
 
 
 (( 
 
 H 
 
 5 
 6 
 8 
 10 
 15 
 20 
 25 
 30 
 
 1865 
 2209 
 2489 
 2848 
 3200 
 3885 
 4150 
 4651 
 
 , 
 
 
 
 
 35 
 
 4828 
 
 Time of flight, 35 sec. 
 
 15-1N. COLUMBIAD. 
 
 40.0 
 
 Shell, 
 
 
 
 273 
 
 
 
 
 302 lbs. 
 
 1 
 2 
 
 484 
 
 812 
 
 
 
 
 M 
 
 3 
 
 1136 
 
 
 
 
 II 
 
 4 
 5 
 
 1310 
 1618 
 
 
 
 
 II 
 
 G 
 
 7 
 
 1760 i 
 1948 
 
 
 
 
 315 lbs. 
 
 8 
 
 2194 
 
 
 
 
 " 
 
 9 
 
 2236 
 
 Time, 8.87 seconds. 
 
 
 
 " 
 
 10 
 
 2425 
 
 " 10.00 
 
 
 
 
 " 
 
 12 
 
 2831 
 
 " 12.07 
 
 
 
 
 
 15 
 
 3078 
 
 " 13.72 
 
 
 
 
 " 
 
 20 
 
 3838 
 
 •' 17.82 
 
 
 
 
 u * 
 
 tl 
 
 25 
 28 
 30 
 
 4528 
 4821 
 5018 
 
 ' : 22.03 
 - 24.18 
 " 26.71 
 
 
 
 45.0 
 
 " 
 
 25 
 
 4595 
 
 •' 23.20 
 
 
 
 50.0 
 
 II 
 
 25 
 
 4680 
 
 " 23.29 " 
 
 10-INCH SEA-COAST 
 
 
 Shell, 
 
 
 
 i 
 
 MORTAR. 
 
 10.0. 
 
 98 lbs. 
 
 45 
 
 4250 
 
 Time, 36 seconds. 
 
 10-INCH SIEGE MOB- 
 
 1.0 
 
 Shell, 
 
 45 
 
 300 
 
 Time, 6£ seconds. 
 
 TAR. 
 
 1.5 
 
 90 lbs. 
 
 45 
 
 700 
 
 ii 12 
 
 
 2.0 
 
 « 
 
 45 
 
 1000 
 
 ,i 14 
 
 
 2.5 
 
 " 
 
 45 
 
 1300 
 
 <i 16 
 
 
 3.0 
 
 " 
 
 45 
 
 1600 
 
 u ]8 
 
 
 3.5 
 
 " 
 
 45 
 
 1800 
 
 ii 10 ii 
 
 
 4.0 
 
 
 45 
 
 2100 
 
 ii 21 ti 
 
 
522 
 
 TABLES OF FIRE. 
 Ranges — Continued. 
 
 Kind of Ordnance. 
 
 Powder. 
 
 Ball. 
 
 Eleva- 
 tion. 
 
 Range. 
 
 Remarks, 
 
 
 Lbs. oz. 
 
 
 
 
 Yards. 
 
 
 8-IXCH SIEGE MORTAR. 
 
 10 
 
 Shell, 
 
 45 
 
 500 
 
 Time, 10 seconds. 
 
 
 13 
 
 46 lbs. 
 
 45 
 
 600 
 
 ii n 
 
 
 1 
 
 " 
 
 45 
 
 750 
 
 " 12J u 
 
 
 1 2 
 
 u 
 
 45 
 
 900 
 
 .i 13 u 
 
 
 1 3 
 
 " 
 
 45 
 
 1000 
 
 " 13* " 
 
 
 1 4 
 
 " 
 
 45 
 
 1100 
 
 u 14 
 
 
 1 6 
 
 
 45 
 
 1200 
 
 " 14* " 
 
 
 Oz. 
 
 
 
 
 
 24-PDR. COEHORN 
 
 0.5 
 
 Shell, 
 
 45 
 
 25 
 
 
 MORTAB. 
 
 1.0 
 
 17 lbs. 
 
 45 
 
 68 
 
 
 
 1.5 
 
 u 
 
 45 
 
 104 
 
 
 
 1.75 
 
 u 
 
 45 
 
 143 
 
 
 
 2.0 
 
 u 
 
 45 
 
 165 
 
 
 
 2.75 
 
 M 
 
 45 
 
 260 
 
 
 
 4.0 
 
 « 
 
 45 
 
 422 
 
 
 
 6.0 
 
 (( 
 
 45 
 
 900 
 
 
 
 8.0 
 
 M 
 
 45 
 
 1200 
 
 
 
 Lbs. 
 
 
 
 
 
 10-PDR. PARROTT 
 
 1.0 
 
 Shot, 
 
 
 
 380 
 
 Time, 1£ second. 
 
 and 
 
 
 10 lbs. 
 
 1 
 
 645 
 
 II J£ H 
 
 3 -INCH RIFLE GUN. 
 
 
 ii 
 
 2 
 
 1000 
 
 H 2 | II 
 
 
 
 u 
 
 3 
 
 1300 
 
 ii 4 
 
 
 
 u 
 
 4 
 
 1525 
 
 .. 4f 1. 
 
 
 
 ii 
 
 5 
 
 1835 
 
 1. 6 
 
 
 
 u 
 
 6 
 
 2100 
 
 " Ii " 
 
 
 
 il 
 
 7 
 
 2325 
 
 u 8 
 
 
 
 (i 
 
 10 
 
 2900 
 
 ii n 
 
 
 
 (( 
 
 12 
 
 3270 
 
 41 13 
 
 
 
 II 
 
 15 
 
 3820 
 
 " 15* " 
 
 
 
 II 
 
 20 
 
 5000 
 
 II 19 | u 
 
 
 
 ii 
 
 25 
 
 5600 
 
 " 23* M 
 
 
 
 ii 
 
 30 
 
 5900 
 
 " 27* " 
 
 
 
 u 
 
 35 
 
 6200 
 
 " 31* u 
 
 20-PDR. PARROTT. 
 
 2.0 
 
 20 lbs. 
 
 5 
 
 2200 
 
 
 
 
 i< 
 
 10 
 
 3500 
 
 
 
 
 u 
 
 15 
 
 4400 
 
 
 100-PDR. PARROTT. 
 
 10.0 
 
 100 lbs. 
 
 10 
 
 3555 
 
 
 
 
 jti 
 
 15 
 
 4940 
 
 
 
 
 ii 
 
 20 
 
 5301 
 
 
 
 
 84 lbs. 
 
 10 
 
 3897 
 
 
 
 
 u 
 
 15 
 
 5301 
 
 
 
 
 ii 
 
 20 
 
 6300 
 
 
TABLES OF FIRE. 523 
 
 Ranges with Sea-coast 13-inch Mortars, $6° elevation. 
 
 Charge. 
 
 Mean time of 
 night. 
 
 Least range. 
 
 Greatest range. 
 
 Mean range. 
 
 Lbs. 
 
 Seconds. 
 
 Yards. 
 
 Yards. 
 
 Yards. 
 
 4 
 
 8 
 
 840 
 
 877 
 
 869 
 
 6 
 
 9.5 
 
 1209 
 
 1317 
 
 1263 
 
 8 
 
 11.66 
 
 1653 
 
 1840 
 
 1744 
 
 10 
 
 12.50 
 
 2010 
 
 2128 
 
 2066 
 
 12 
 
 14.25 
 
 2369 
 
 2688 
 
 2528 
 
 14 
 
 15.25 
 
 2664 
 
 2780 
 
 2722 
 
 Ranges 
 
 with 13-inch Mortars, at 45° elevation. 
 
 13-inch Mortar. 
 
 Powder. 
 
 Shell. 
 
 Elevation. 
 
 Range. 
 
 
 Lbs. 
 20 
 
 Lbs. 
 200 
 
 45° 
 
 Yards. 
 4325 
 
 Ranges with 13-inch Mortars, at 45° elevation. 
 
 Charge. 
 
 Flight 
 
 Fuze. 
 
 Range. 
 
 
 Lbs. oz. 
 
 Seconds. 
 
 Inches. lOths. 
 
 Yards. 
 
 
 7 
 
 21.4 
 
 4 2* 
 
 2190 
 
 
 7 8 
 
 22.4 
 
 4 4 
 
 2346 
 
 
 8 
 
 23.2 
 
 4 6 
 
 2480 
 
 
 8 8 
 
 23.8 
 
 4 I* 
 
 2600 
 
 
 9 
 
 24.4 
 
 4 8f 
 
 2734 
 
 
 9 8 
 
 24.9 
 
 4 9f 
 
 2853 
 
 
 10 
 
 25.4 
 
 5 1 
 
 2958 
 
 
 10 8 
 
 25.9 
 
 5 1£ 
 
 3026 
 
 
 11 
 
 26.3 
 
 5 2± 
 
 3150 
 
 
 11 8 
 
 26.7 
 
 5 H 
 
 3246 
 
 
 12 
 
 27.0 
 
 5 4 
 
 3327 
 
 
 12 8 
 
 27.4 
 
 5 4£ 
 
 3404 
 
 
 13 
 
 27.7 
 
 5 H 
 
 3470 
 
 
 13 8 
 
 28.0 
 
 5 6 
 
 3552 
 
 
 14 
 
 28.3 
 
 5 6£ 
 
 3617 
 
 
 14 8 
 
 28.5 
 
 5 7 
 
 3681 
 
 
 15 
 
 29.0 
 
 5 8 
 
 3739 
 
 
 15 8 
 
 29.1 
 
 5 8± 
 
 3797 
 
 
 16 
 
 29.2 
 
 5 8£ 
 
 3849 
 
 
 16 8 
 
 29.4 
 
 5 8£ 
 
 3901 
 
 
 17 
 
 29.6 
 
 5 9 
 
 3949 
 
 
 17 8 
 
 29.8 
 
 5 H 
 
 3997 
 
 
 18 
 
 29.8 
 
 5 9£ 
 
 4040 
 
 
 18 8 
 
 30.0 
 
 6 
 
 4085 
 
 
 19 
 
 30.2 
 
 6 0* 
 
 4123 
 
 
 19 8 
 
 30.3 
 
 6 0£ 
 
 4160 
 
 
 20 
 
 30.5 
 
 6 1 
 
 4200 
 
 
APPENDIX 
 
APPENDIX 
 
 ARMSTRONG GUN. 
 
 1. Description of piece. The following: description of the Arm- 
 strong gun is principally gathered from Sir Howard Douglas's Naval 
 Gunnery and the Official Manual of Artillery Exercises. Although 
 wanting in some of the details, it is more complete and correct than 
 that given in the preceding pages. 
 
 Body of the piece. The body of the piece is made up by welding 
 together several wrought-iron tubes ; each tube is from two to three 
 feet long, and is formed by twisting a square bar of iron around a 
 mandrill, and welding the edges together. Thus far the piece resem- 
 bles the barrel of a fowling-piece. To strengthen the barrel at and in 
 rear of the trunnions, it is enveloped with two additional thicknesses, 
 or tubes. The outer tube, like the inner one, consists of spiral coils ; 
 but the intermediate tube is formed of an iron slab, bent into a cir- 
 cular shape and welded at the edges. The reason for this distinction 
 is, that the intermediate layer has chiefly to sustain the pressure on 
 the bottom of the bore, while the other layers are formed to resist the 
 tangential strain. 
 
 Fig. 155. 
 Breech. The breech, is closed with a vent-piece (6), fig. 155, 
 which is slipped with the hand into a slot cut in the breech of the 
 piece, and held in its place by a breech-screw (a), which supports it 
 from behind. 
 
528 
 
 APPENDIX. 
 
 This screw is made in the form of a tube, so that its hollow forms a 
 part of the bore prolonged, when the vent-piece is withdrawn. The 
 object of this hollow is to allow the charge to be passed into the 
 chamber. 
 
 Bore. The bore of the field-gun, which is represented in the draw- 
 ing, is three inches in diameter, and it is rifled with thirty-four narrow 
 grooves. Twist, one turn in 9 feet. 
 
 The diameter of the chamber is one-eighth of an inch larger than 
 that of the bore. 
 
 Vent. The vent is formed in the breech-piece in order that, when 
 it becomes enlarged, it may be easily replaced. For this purpose, 
 spare breech-pieces are carried with each battery. The diameter of the 
 vent is \ inch, and it is primed by filling it with a small paper car- 
 tridge of fine powder, which is ignited by an ordinary friction-tube. 
 
 It is not stated whether the gas is allowed to escape through the 
 joint; but it was shown in the experiments made at West Point, that 
 the escape can be easily prevented by a gas-check of soft metal (/). 
 
 Projectile. Only one kind of projectile is used for field-guns, and 
 that is so constructed that it may operate as a shot, shell, or case-shot, 
 at pleasure. 
 
 It consists — see figure 156 — of a very thin cast-iron shell (^4 A), 
 enclosing forty-two segment-shaped pieces of cast 
 iron (B B), built up so as to form a cylindrical 
 cavity in the centre (D), which contains the burst- 
 ing-charge and the concussion-fuze. The exterior 
 of the shell is thinly coated with lead (C (7), which 
 is applied by placing the shell in a mould and pour- 
 ing it in a melted state. The lead is also allowed to 
 percolate among the segments, so as to fill up the 
 interstices, the central cavity being kept open by the 
 insertion of a steel core. 
 
 In this state the projectile is so compact that it 
 may be fired through six feet of hard timber without 
 injury ; while its resistance to a bursting-charge is so 
 small, that less than one ounce of powder is required 
 to burst it. When the projectile is to be fired as a 
 shot, it requires no preparation ; but the expediency 
 of using it otherwise than as a shell is much doubted. 
 
ARMSTRONG GUN. 529 
 
 To make it available as a shell, the bursting-tube, the concussion and 
 time fuzes, are all to be inserted ; the bursting-tube entering first, and 
 the time-fuze being screwed in at the apex. If then the time-fuze be 
 correctly adjusted, the shell will burst when it reaches within a few yards 
 of the object ; or, failing to do so, it will burst by the concussion-fuze 
 when it strikes the object, or grazes the ground near it. If it be required 
 to act as a canister-shot upon an enemy close to the gun, the regulator 
 of the time-fuze must be turned to the zero of the scale, and then the 
 shell will burst on leaving the gun. 
 
 The explosion of one of these shells in a closed chamber, where the 
 pieces could be collected, resulted in the following number of frag- 
 ments : — 
 
 106 pieces of cast iron; 90 pieces of lead, and 12 pieces of fuze, 
 &c. ; making in all 217 pieces. 
 
 Fuzes. The time and concussion fuzes may act together or sepa- 
 rately. 
 
 The body of the time-fuze is made of pewter, and the composition is 
 arranged in a circular trough, as in the Bormann fuze. As the shell 
 fits accurately into the chamber, there is no passage of the flame by 
 which the fuze can be ignited ; this defect, however, is obviated by 
 attaching a small striker to the fuze, which breaks from its fastenings 
 by its inertia, when the piece is fired, and impinges against and explodes 
 a small charge of percussion-powder. 
 
 The flame from the percussion powder acts, through a small channel, 
 upon any desired point of the circular column, simply by turning the 
 piece in which the channel is formed, so that the orifice shall rest upon 
 the point of ignition. 
 
 The concussion-fuze is made on the same principle as the concussion 
 arrangement of the time-fuze. A striker, with a point to the front, is 
 secured in a tube by a wire fastening, which is broken on firing the 
 gun ; the striker, being liberated, recedes through a small space, and 
 rests at the bottom of the tube, but as soon as the shell meets with any 
 check in motion, the striker runs forward and pierces the percussion- 
 powder in front, by which means the bursting-charge is ignited. 
 
 Loading. The piece is loaded by placing the projectile (e), with the 
 
 greased wad (d) and cartridge (c), in the hollow of the breech-screw, 
 
 and pushing them, separately or collectively, by a rammer, into the 
 
 bore. 
 
 34 
 
530 APPENDIX. 
 
 The vent-piece is then dropped into its place, and secured by a half- 
 turn of the screw-handle Qi). 
 
 In the early guns, it was necessary that the portion of the bore which 
 was occupied by the shot should be perfectly clean, otherwise the shot 
 would not always enter its place. It was necessary, therefore, to use a 
 wet sponge ; but, in the new guns now issued for service, a slight alter- 
 ation in the bore permits a greased wad to be employed with perfect 
 success, as a substitute for the sponge. The gun can now be fired with 
 great rapidity, and apparently for any length of time, without being 
 sponged at all. 
 
 The cartridge is made of serge, shaped to fit the chamber easily. The 
 powder for these guns is slower than that generally used in service ; it 
 contains a smaller proportion of nitre, and is worked one hour instead 
 of three. Although this powder is better suited to the Armstrong guns, 
 giving much greater regularity of range and deflection, yet the service- 
 powder may be used whenever necessary. The charge is one-eighth of 
 the weight of the projectile. 
 
 Range and deflection. The velocity of the Armstrong projectile 
 diminishes very little with the range ; consequently the range will be 
 nearly as the time of flight. The velocity averages about 950 feet per 
 second. 
 
 Up to 500 yards, one minute of elevation may be assumed to give 
 10 yards range. 
 
 From 500 to 1,000 yards, one minute of elevation gives 1 yards 
 range. 
 
 From 1,000 to 3,000 yards, one minute gives 6 yards; at distances 
 above 3,000 yards, one minute gives 5 yards. 
 
 The Armstrong guns always throw to the right, increasing with the 
 range ; this is termed a constant deflection (drift?), and must be allowed 
 for ; and for this purpose the rear sight is susceptible of a lateral mo- 
 tion or adjustment. 
 
 Eight degrees of elevation give a range of about 3,000 yards. 
 Carriage. In connection with the elevating apparatus, the field- 
 carriages have a means for giving a slight transverse motion to the piece 
 in pointing. 
 
 The ship and sea-coast carriages have a self-acting arrangement for 
 returning the piece to battery after recoil. 
 
FIFTEEN-INCH COLUMBIAD. 531 
 
 15-INCH COLUMBIAD. 
 
 2. Description, &c. The principal difficulties heretofore ex- 
 perienced in the manufacture of very large cast-iron cannon were, the 
 injurious strains produced by cooling the castings from the exterior 
 and the enormous pressures arising from large charges of powder com- 
 posed of the ordinary-sized grains. 
 
 Captain Rodman, of the ordnance department, who had been en- 
 gaged for many years in making experiments with a view of solving 
 these difficulties, arrived at the conclusion that they could be entirely 
 overcome : 1st. By cooling the casting from the interior by means of a 
 current of cold water flowing through a hollow core ; and, 2d. By the 
 use of very large-grained powder, or by hollow-cake powder, both of 
 which kinds burn more progressively than that usually employed. Ac- 
 cordingly, this officer was induced to submit to the war department 
 the plan of a cast-iron cannon of much greater dimensions and power 
 than any heretofore tried. The plan was approved, and the piece was 
 made at the Fort Pitt Foundry, Pittsburgh, Pa., under the immediate 
 supervision of its projector. 
 
 De cription. The form of the piece, which is evidently a great im- 
 provement on that of the old columbiads, is shown in the accompany- 
 ing figure. 
 
 Fig. 157. 
 
 The principal dimensions, &c, are as follows, viz. : 
 
 Diameter of bore, 15 inches. 
 
 Length of bore, including elliptical chamber, 165 " 
 Weight of rough casting, . . . 78,000 lbs. 
 
 Weight of finished piece, . 49,090 " 
 
 Diameter of shell, . . . . 14-9 inches. 
 
532 
 
 APPENDIX. 
 
 Weight of shell . . . . 320 lbs. 
 
 Bursting-charge . . . . . 17 " 
 
 Charge of piece (large-grain .6 in. diam.), . 40 " 
 " " (cake-powder), . . . 50 " 
 
 The mean velocity in passing over the first 885 feet from the gun, as 
 determined by the fall of the projectile, is, for the grain-powder, 1,328 
 feet, and, for the cake-powder, 1,282 feet. 
 
 Ranges, &c. The ranges, time of flight, elevations, &c, are as fol- 
 lows : — 
 
 POWDER. 
 
 Elevation. 
 
 Range. 
 Yards. 
 
 Time of 
 flight. 
 
 Seconds. 
 
 
 Kind. 
 
 Weight, 
 lbs. 
 
 Cake 
 Grain (.6) 
 
 M 
 M 
 U 
 U 
 « 
 M 
 U 
 u 
 if 
 
 40 
 u 
 
 u 
 
 35 
 
 M 
 
 u 
 
 40 
 
 M 
 M 
 
 a 
 
 M 
 
 (( 
 M 
 
 
 
 a 
 U 
 
 6° 
 
 M 
 
 u 
 
 10° 
 u 
 
 u 
 
 28° 35' 
 
 M 
 
 258 
 276 
 293 
 1,973 
 1,970 
 1,979 
 2,700 
 2,210 
 2,754 
 2,760 
 5,435 
 5,062 
 5,730 
 
 7". 
 
 6".75 
 
 7 // . 
 11".48 
 11".30 
 10". 80 
 ll /r .06 
 24 ,, .82 
 25". 
 27". 
 
 V. A.. J 
 
 Over water. At target. 
 
 The axis of the piece was 13f feet above the water. 
 
 Deviation. The mean range, at 6° elevation, of ten shots, was 1,936 
 yards ; and the mean lateral deviation, 2.2 yards. The lateral devia- 
 tion for 28° 35', as observed with a telescope attached to one of the 
 trunnions, was very slight. 
 
 Pressure. The pressure on the surface of the bore, as indicated by 
 Captain Rodman's internal pressure pings, was about one-half less for 
 the cake than the grain powder ; at the same time the pressure of the 
 charge of cake-powder was only about one-fourth of that on the bore of 
 the 10-inch columbiad with its proper charge of service-powder. The 
 comparative pressures are determined by the lengths of the indentations 
 
EXPEKIMENTS WITH POWDER. 533 
 
 made in copper ; the absolute pressure in pounds is not given in the 
 report from which this information is derived. 
 
 Endurance. After five hundred rounds, the bore and vent were 
 carefully examined and measured ; the enlargement of the former was 
 inappreciable, while that of the latter was very uniform, and less than 
 is usual in large cast-iron cannon. The projector infers from these facts, 
 that the piece will bear 1,000 rounds without material injury. 
 
 Manoeuvre. The piece was fired from an iron carriage of the new 
 pattern (page 243), and was manoeuvred with great facility by a small 
 force of men. 
 
 During the trials, it was manned with one sergeant and six negroes, 
 and the times of loading, &c, were as follows, viz. : 
 
 The times of loading, 1' 15", 1', and 1' 3". 
 
 Time occupied in traversing 90°, 2' 20", and in turning back 45°, 1'. 
 
 Times of loading, including the depression of the piece from 28° 
 35', sponging, loading, and elevating again to 28° 35', were 4' and 
 3' 10". 
 
 EXPERIMENTS WITH GUNPOWDER. 
 
 3. Object. In the sumWr of 1860, the chief of ordnance directed 
 a series of experiments to be made at Fort Monroe and West Point, to 
 ascertain the effect of increasing the size of the grains of cannon- 
 powder. 
 
 The object of the experiments at Fort Monroe was to determine the 
 pressure, initial velocity, and range, of various kinds of powder in the 
 larger service-cannon ; while those at West Point were to determine 
 the same points with reference to the 6-pdr. gun-pendulum, the results 
 of which are applicable to field-cannon. 
 
 Description of powders. The powders tested were of two kinds of 
 manufacture (Hazard's and Dupont's), and ten different sizes of grains, 
 as follows : 
 
 No. 1, 2 grains of powder weighed 100 grains Troy. 
 " 2, 4 
 
 " 3, 8 
 
 " 4, 16 
 * 5, 32 
 '• 6, 64 
 " 7, 128 
 
 It 
 
 It 
 
 it 
 
 it 
 
 it 
 
 tt 
 
 it 
 
 it 
 
 it 
 
 U 
 
 n 
 
 M 
 
 14 
 
 it 
 
 U 
 
 it 
 
 it 
 
 it 
 
534 APPENDIX. 
 
 No. 8, 250 grains of powder weighed 100 pounds Troy. 
 u 9) 500 u m u « « 
 
 " 10, 1000 " " " " " 
 
 The size of the service-grain is about 1,500 grains to the 100 grains 
 Troy. The mean specific gravity of Dupont's powder was about 1.710 ; 
 that of Hazard's, about 1,550, as taken with a densimetre a mercure. 
 
 Experiments. The instruments employed in the West Point ex- 
 periments were : — 
 
 Rodman's indenting apparatus, to determine the pressure on the 
 bottom of the bore. 
 
 A 6-pdr. gun-pendulum, to determine the initial velocity impressed 
 upon the projectile. 
 
 An electro-ballistic machine (Navez's), to determine the time of pas- 
 sage of the ball over a certain distance in front of the pendulum. 
 
 And a plane table, to obtain the range of the projectile over water. 
 
 The position of the diameter passing through the centre of gravity 
 of the ball was determined by floating in a bath of mercury, and it was 
 secured in the axis of the bore by means of a grommet wad. 
 
 Table of the mean results of three fires with each specimen of 
 powder. Charge, \\ lb. 
 
 
 HAZARD'S. 
 
 
 DUPONT'S. 
 
 
 4a 
 
 C3 *S 
 
 Initial Velocity. 
 
 
 a J3 
 
 Initial Velocity. 
 
 
 Q 
 
 i 
 
 a 
 
 Cm 
 
 
 
 ft © 
 
 el 
 
 3 m 
 
 Feet. 
 
 •E 
 
 g 
 
 o .5 
 
 Feet. 
 
 CS 
 
 | 
 
 a a 
 
 be 3 
 
 li 
 
 •w> 3 
 
 o X 
 
 © 3 
 
 Ec"s 
 
 © 3 
 
 
 <J2 © 
 
 PQ© 
 
 « ft 
 
 a 
 
 ■ 
 
 8 2 
 
 ^ a 
 ^ ft 
 
 11 
 
 
 1 
 
 11,277 
 
 1319 
 
 1233 
 
 281 
 
 2,846 
 
 786 
 
 798 
 
 223 
 
 2 
 
 9,170 
 
 1319 
 
 1253 
 
 283 
 
 4,250 
 
 1056 
 
 1036 
 
 231 
 
 3 
 
 8.047 
 
 1303 
 
 1322 
 
 256 
 
 5,213 
 
 1077 
 
 1093 
 
 237 
 
 4 
 
 15,860 
 
 1333 
 
 1330 
 
 289 . 
 
 8,503 
 
 1207 
 
 1193 
 
 274 
 
 5 
 
 34,423 
 
 1446 
 
 1532 
 
 265 1 
 
 8,180 
 
 1224 
 
 1203 
 
 272 
 
 6 
 
 47,477 
 
 1468 
 
 1521 
 
 299 
 
 8,246 
 
 1238 
 
 1218 
 
 243 
 
 7 
 
 55.530 
 
 1473 
 
 1455 
 
 28S ; 
 
 13,953 
 
 1295 
 
 1326 
 
 258 
 
 8 
 
 54,140 
 
 1476 
 
 1474 
 
 313 
 
 22,730 
 
 1345 
 
 1345 
 
 268 
 
 9 
 
 59,04G 
 
 1436 
 
 1502 
 
 259 ! 
 
 41,130 
 
 1462 
 
 1463 
 
 289 
 
 10 
 
 64,310 
 
 1500 
 
 1505 
 
 302 
 
 40,163 
 
 1426 
 
 1414 
 
 293 
 
 Mean 
 
 35,928 
 
 1415 
 
 1413 
 
 283 
 
 15,522 
 
 1212 1209 
 
 2*59 
 
RIFLE-PROJECTILES. 535 
 
 4. Conclusions 1st. The pressures, initial velocities, and ranges 
 of Hazard's powders, were greater than Dupont's, in the following 
 ratios : 
 
 Pressures, 2.36 
 
 Initial velocities — 
 
 By gun-pendulum, . . . 1.16 
 
 By electric machine, . . 1.1 7 
 
 Range, 1.11 
 
 2d. In both kinds of powders, the pressures, initial velocities, and 
 ranges increase, while the size of the grain diminishes; the increase of 
 pressure, however, is much more rapid than the increase of initial ve- 
 locity and range". 
 
 3d. In mixed charges (results not given), the pressures were least 
 in those which had the greatest proportion of large grains ; the differ- 
 ence in range, however, was very slight. 
 
 4th. The velocities and ranges obtained with service-charges of 
 fine, medium, and coarse grain powders, in an 18-pounder siege-gun, 
 were nearly alike. The pressure-plug was not applied, as the trials 
 of these powders in the heavy guns were to be made at Fort Monroe. 
 
 The velocities obtained by the gun-pendulum are more uniform than 
 those obtained by the electric machine, although the mean results are 
 very nearly the same. The excess of the latter over the former, in 
 many instances, may have arisen from placing the wire across the muz- 
 zle of the pendulum-gun (in which case it was broken by the flame 
 before the ball reached it), and by giving too great a value to the con- 
 stant N, in the formula for the velocity by the gun-pendulum. 
 
 RIFLE-PROJECTILES. 
 
 5. Different systems. The rifle-projectiles used 
 in the United States, service belong to the expand- 
 ing class. The following are among the most prom- 
 inent used in the land service, viz. : 
 
 ParrotCs. Parrott's projectile is composed of a cast- 
 iron body (a) and a brass ring (6) cast into a rabate at 
 the base of the body (see fig. 158.) 
 
 The gas insinuates itself under the ring, forcing it 
 Pig 158. outward into the rifles of the bore. In the smaller 
 projectiles it is necessary to open the ring slightly for the entrance 
 
536 
 
 APPENDIX. 
 
 Fig. 159. 
 
 of the gas. Some of the projectiles used in Parrott's guns have a 
 wrought-iron expanding cup attached to the base, constituting a 
 modification of the Reed projectile. 
 
 The iron cups do not possess any advantage over 
 the brass rings. 
 
 SchenkWs. Schenkle's projectile is shown in fig. 
 159. It is composed of a cast-iron body (a), the pos- 
 terior portion of which terminates in a cone. The 
 expanding portion is a papier mache wad (b). which 
 being forced forward on to the cone, is expanded 
 into the rifling of the bore. On issuing from the 
 bore the wad is blown to pieces, leaving the pro 
 jectile entirely unincumbered in its flight through 
 the air. 
 
 Hotchkiss. Hotchkiss' projectile is composed of 
 three parts, the body (a), the expanding ring of soft 
 metal (6), and the cap (c), see fig. 160. The action, 
 of the charge is to crowd the cap against the soft 
 metal, thereby expanding it into the rifling of the 
 bore. 
 
 Sawyer. Sawyer's projectile has six rectangular 
 flanges, corresponding to the grooves of the bore, 
 and therefore belongs to the flanged class. To soften 
 the contact of the projectile with the surface of the 
 Fig. 160. bore, the entire surface of the projectile is covered 
 
 with a soft metal coating cast on. The soft metal at the bottom is 
 made thicker than at the sides to admit of being 
 expanded into the grooves, and thereby closing the 
 windage. 
 
 James. The expanding part of James's projectile 
 consists of a hollow (c), fig. 161, formed in the 
 base of the projectile ; and eight openings (6), which 
 extend from this hollow to the surface, for the pas- 
 sage of the gas, which presses against and expands 
 into the grooves of the bore, an envelope or patch 
 (e), composed of paper, canvas, and lead, a repre- 
 Fig. 161. sents the body of the projectile, which, in this case, 
 
 is a solid shot ; and d is a partition between two of the openings, 
 
INDEX 
 
 Absolute force of gunpowder, 55. 
 
 Accidents, from the spontaneous combus- 
 tion of charcoal, 17 ; with percussion 
 locks, 297. 
 
 Aiming a fire-arm, 299. 
 
 Air, effect of the resistance of, on a rifle 
 projectile, 177 ; resistance of the, 40 i ; 
 fall of a projectile in the, 404 ; trajec- 
 tory in the, 412-424. 
 
 Alcohol in pyrotechny, 347. 
 
 Ammunition for small-arms, 348 ; for 
 field and mountain cannon, 351; for 
 siege and sea-coast cannon, 353 ; prep- 
 arations for the service of, 358. 
 
 Analysis of gunpowder, 30. 
 
 Ancient arms, 270. 
 
 Ancient guns. 106. 
 
 Ancient howitzers, 107. 
 
 Ancient mortars, 106. 
 
 Ancient theory respecting length of can- 
 non, 127. 
 
 Angle of arrival, in ricochet fire, 453. 
 
 Angle of fire, definition of, 437 ; in rico- 
 chet firing, 455. 
 
 Angle of sight, definition of, 437. 
 
 Antimony in pyrotechny, 345. 
 
 Appendix, 525. 
 
 Armament of sea-coast batteries, 503. 
 
 Armor, ancient, 272. 
 
 Armor, defensive, 286. 
 
 Armorer, dismounting of fire-arms by an, 
 335. 
 
 Armories of the United States, where sit- 
 uated, 320. 
 
 Arms, package and storage of, 330 ; pres- 
 ervation and care of, when in service, 
 332. 
 
 Arms in service, inspection of, 336. 
 
 Armstrong's rifle-gun, how constructed, 
 150; experiments made with, in breech- 
 ing, 485; description of, 527. 
 
 Arquebuse, history and description of 
 the, 273. 
 
 Arsenals, how classified, 268. 
 
 Artillery, materiel of, 108 ; system of, 
 108 ; first system of, in the 16th cen- 
 tury, 109; second system of, in the 
 reign of Louis XIV., 110; Valiere's 
 system of, 110; G-ribeauval's system 
 of, 111; Louis Napoleon's system of, 
 112; stock trail system of, 112; im- 
 portant recent improvements in, 113 ; 
 General Paix nan's system of, 166 ; im- 
 plements and machines for, 248. 
 
 Artillery carriages, classification of, 212; 
 preservation and repairs of, 259; how 
 to destroy, 259 ; materials for, 261- 
 266 : construction of, 267 ; painting 
 of, 268. 
 
 Artillery harness, 215, 218. 
 
 Artillery wheel, 220. 
 
 Astragal of field guns, 115. 
 
 Attachment of artillery harness, 216- 
 217. 
 
 Austrian army bullet, 313. 
 
 Axle-tree of the artillery carriage, 226; 
 of the field limber, 231. 
 
 Back-action lock, 297. 
 
 Bags of powder, explosive force of, 376. 
 
 Ballistic machine at West Point, 390, 
 
 395; table of times calculated for, 515. 
 Ballistic machine of Captain Navez, 389. 
 Ballistic pendulum, 383, 388. 
 Ballistics, history of, 382. 
 Balloting in the bore a cause of rotation, 
 
 425. 
 Bands of portable fire-arms, 300. 
 Barbette sea-coast carriages, 247. 
 Barrel of portable fire-arms, 290; length 
 
 of, 316-319; inspection of, 328. 
 Barrel of the rifle-musket, how cleaned, 
 
 333. 
 Bar-shot, description of, 83. 
 Base of the breech of cannon, 115. 
 Base-ring of cannon, 115. 
 
538 
 
 INDEX. 
 
 Battery-wagon, how employed, 236 ; de- 
 scription of, 237. 
 
 Battle-axe, ancient, 270. 
 
 Bayonet, origin and history of the, 276; 
 description of, 280 ; inspection of, 329 ; 
 when unserviceable, 337. 
 
 Beeswax and tallow, a lubricant for fire- 
 arms, 316; in pyrotechnv, 347. 
 
 Bill-hook, 259. 
 
 Bill of timber, 266. 
 
 Blistered steel, how made, 140. 
 
 Blue color, how produced on the surface 
 of iron and steel, 326. 
 
 Blue-light, ingredients for, 369. 
 
 Bombard, early cannon, 104; how con- 
 structed, 105. 
 
 Bomford, Colonel, plan of, for determin- 
 ing pressure of the charge in cannon, 
 152; columbiad invented by, 190. 
 
 Borda, experiments of, in relation to the 
 forms of projectiles, 4 1 0. 
 
 Bore, influence of length of, on velocity 
 of projectile, 127 ; effect of length of, 
 on maximum charge, 131 ; length of, 
 in field cannon, 180; use of projectiles 
 not suited to, 435. 
 
 Bore of Armstrong gun, 528. 
 
 Bore of cannon, 116; inspection of, 201 ; 
 enlargement of, 208, 210. 
 
 Bore of fire-arms, length of, 127. 
 
 Bore of rockets, 96. 
 
 Boring cannon, 199; vent of cannon, 200; 
 musket- barrels, 323. 
 
 Bormann fuze, description, 362. 
 
 Bow, the ancient, 271. 
 
 Breach, firing in, 496. 
 
 Breaching walls of fortifications, 481 ; 
 with rifle-cannon, 485. 
 
 Breech of Armstrong gun, 527. 
 
 Breech of cannon, 115; best form of, for 
 strength, 120 ; thickness of, 157. 
 
 Breeching of artillery horses, 219. 
 
 Breech-loading arms, 301 ; advantages 
 of, 307. 
 
 Breech -loading cannon, early, 105; pro- 
 jectiles for, 170. 
 
 Breech-sight, how used, 255. 
 
 Breech-screw of portable fire-arms, 291. 
 
 British service bullet, 313. 
 
 Bronze as a material for cannon, 138 ; 
 density and tenacity of, 139. 
 
 Bronze cannon, copper vent-pieces made 
 for, 117 ; injured by the melting of the 
 tin, 139; inspection of, 204; defects 
 in, 205; how proved, 206; liable to 
 injury from lodgement. 210. 
 
 Browning musk -t-barrels, 327. 
 
 Buckshot cartridge. 349. 
 
 Budge-barrel, for carrying cartridges, 252. 
 
 Buildings for pyrotechny, how arranged, 
 342. 
 
 " Built-up " cannon, noted instances of, 
 150. 
 
 Bullets for small-arms, 76 ; present form 
 of expanding, 312 ; in use in the Unit- 
 ed States and Europe, 312, 314; elon- 
 gated, proper charge of powder for, 
 315; how made, 348; effects of, 486. 
 
 Burnside's system of " packing the joint" 
 of breech-loading arms, 303. 
 
 Butt of a musket, length and shape cf, 
 298. 
 
 Butt-plate of portable fire-arms, 300. 
 
 Cadet-musket, description of, 317. 
 
 Caisson, description of the, 235 ; how to 
 destroy, 259. 
 
 Cake powder made by compression of 
 grain powder, 52; compared with grain 
 powder, 154. 
 
 Calibre of cannon, 107 ; of siege guns, 
 184; of portable fire-arms, 293. 
 
 Calibres in the American service (note), 
 107. 
 
 Canister fire, 468 ; of field artillery, 492. 
 
 Canister-shot, description of, 81. ' 
 
 Cannon, shape of the first, 104; early, 
 construction of, 105; calibre of, 107; 
 devices on, 108; construction of, 114; 
 interior form of, 116; influence of length 
 of bore of, on velocity of projectile, 127; 
 materials best adapted for the construc- 
 tion of, 131, 132 ; strength of, how af- 
 fected by cooling, 134; course of the 
 fracture of, in bursting, 136 ; materials 
 principally used in the fabrication of, 
 138; thickness of the metal of, 151; 
 exterior form of, 151 ; nature of force 
 to be restrained by, 153 ; various kinds 
 of strain upon, 154 ; nomenclature of 
 the exterior of, 157; peculiar form of, 
 made in Sweden, 159; position of the 
 centre of gravity of, 163 ; weight of, 
 how determined, 165 ; different kinds 
 of, 166 ; rifled, 167 ; uses to which ap- 
 plied, 180; mountain and prairie, 183; 
 for sea-coast batteries, 188 ; where 
 made, 194 ; proof of, 205 ; bronze, how 
 proved, 206 ; inspection marks on, 207 ; 
 how marked when rejected, 207 ; inju- 
 ries to, caused by service, 207 ; how 
 disabled, 260. 
 
 Cannon-balls, preservation and piling of, 
 93. 
 
 Carbine, description of, 317. 
 
 Carcass, description of. 84 ; composition 
 and preparation of, 371. 
 
 Carriage of Armstrong gun, 530. 
 
 Carriages, artillery 212; materials for, 
 261-266. 
 
 Carronades, description of, 194. 
 
 Cartridge-bags, how made, 352, 353. 
 
INDEX. 
 
 539 
 
 Cartridge of the rifle-musket, 349. 
 
 Cartridge with buckshot, 349. 
 
 Cartridges, materials for preparing, 348 ; 
 for small-arms, how packed, 349 ; num- 
 ber expended in European wars, 469. 
 
 Cascable of cannon, parts of the, 114; 
 knob of the, 163. 
 
 Case-hardening, the process of, 325. 
 
 Casemate carriages, 247. 
 
 Casemate howitzer, 193. 
 
 Casern ite truck, for moving cannon, 250. 
 
 Case of a signal rocket, 366. 
 
 Cases for fireworks, how made, 357. 
 
 Case-shot, description of, 80 ; fabrication 
 of spherical, 88 ; when to be fired in 
 defence or attack of a work, 496. 
 
 Cast-iron, projectiles of, 72; effect of 
 cooling on the strength of cannon made 
 of, 134; better adapted for large than 
 small cannon, 136; advantages and dis- 
 advantages of, as a material for can- 
 non, 145; causes which affect the qual- 
 ity of, 145 ; how tested for cannon met- 
 al, 145; general properties of, 147 ; te- 
 nacity of, injured by the presence of 
 sulphur, 149 ; endurance of, 211 ; in- 
 juries to cannon made of, 211; effect 
 of projectiles on, 471. 
 
 Cast-steelj how made, and characteristics 
 of, 141. 
 
 Cavalry, effect of field artillery against, 
 490. 
 
 Cavalry sabre, description of, 284. 
 
 Cavities in cannon, how produced, 208. 
 
 Centre of gravity of projectiles, 74; effect 
 of the position of, 178. 
 
 Centre of gravity of cannon, position of, 
 163. 
 
 Chain-ball, proposed to be attached to 
 projectiles, 75. 
 
 Chain-shot, 83. 
 
 Chambers of fire-arms, 121-123. 
 
 Charcoal, 15; properties of, 16; quality 
 of, affected by temperature in manufac- 
 ture, 16; spontaneous combustion of, 
 1 7 ; combustibility of various kinds of, 
 18, 19 ; influence of trituration on the 
 combustibility of, 19; quantity of, in 
 gunpowder, 31; pulverized, used in 
 the process of casting cannon, 196 ; in 
 pyrotechny, 345. 
 
 Charge, force of, influenced by the form 
 of its seat, 120; influence of windage 
 on the force of, 125; maximum, 130; 
 the most suitable for smooth-bored 
 cannon, 131 ; proportion of, to weight 
 of projectile, 131; effect of length of 
 bore on maximum, 131; to determine 
 the pressure of, by calculation, 151; to 
 determine the pressure of, by experi- 
 ment, 152 ; for field guns and howit- 
 
 zers, 181; for siege guns, 185; for 
 proving cannon, 206 ; in ricochet fire, 
 to find, 455. 
 
 Charge of rupture of shells, 84. 
 
 Chase of cannon, 115 ; thickness of, 158. 
 
 Chassis for sea-coast gun-carriages, 245. 
 
 Chassis-rails, props of, 247. 
 
 Cheeks of artillery carriages, 226. 
 
 Chlorate of potassa, used in the manufac- 
 ture of gunpowder, 14 ; in pyrotechny, 
 344. 
 
 Classification of cannon, 114; of artillery 
 carriages, 212 ; of arms in service, 339; 
 of fires, 450. 
 
 Closing the breech of breech-loading arms, 
 302. 
 
 Coehorn mortar, description of, 188 ; 
 range of, 522. 
 
 Coke- wash, use of, in the process of cast- 
 ing cannon, 198. 
 
 Coloring materials in pyrotechny, 346. 
 
 Colt's pistol, description of, 318. 
 
 Columbiads, history and description of, 
 190; improved model of, adopted in 
 1860, 191 ; dimensions of the improved, 
 192 ; large, and iron-plated vessels 
 (note), 473; ranges of, 520; the 15- 
 inch, description of, 531. 
 
 Columbiad-shell, bursting-charge of, 355. 
 
 Combined metals, as materials for cannon, 
 149. 
 
 Combustibility of various kinds of char- 
 coal, 18, 19. 
 
 Combustion of gunpowder, velocity of, 
 39 ; nature of the products of, 52 ; gas- 
 eous products resulting from, 53. 
 
 Compositions for military fireworks, 356; 
 for signal rockets, 366. 
 
 Compound projectiles, 73. 
 
 Compressible fluid, resistance of, 403. 
 
 Compression, strain by, upon cannon, 
 154. 
 
 Concave cutting-edge, action of, 283. 
 
 Concentric projectiles, effect of rotation 
 on, 427. 
 
 Concussion fuze, description of, 364. 
 
 Cone of portable fire-arms, 292 ; defects 
 in, 337. 
 
 Congreve rocket, how guided, 99. 
 
 Congreve, Sir William, improvements 
 made by, in the construction of rock- 
 ets, 102. 
 
 Conical chambers of fire-arms, 122. 
 
 Construction of artillery carriages, 267. 
 
 Construction of early cannon, 105. 
 
 Construction of cannon, 114. 
 
 Construction of rockets, 94. 
 
 Continuous effort exerted by draught- 
 horses, 214. 
 
 Convex cutting-edge, action of. 283. 
 
 Cooling effect of, on the strength of can- 
 
540 
 
 INDEX. 
 
 non, 134 ; unequal, effects of in cannon 
 modified by time, 137 ; influence of, on 
 the color and texture of cast-iron, 149. 
 
 Cooling cannon, 136, 198. 
 
 Corrosion, cannon metal should be able 
 to resist, 138. 
 
 Counter and enfilading fires with siege 
 cannon, 494. 
 
 Cracks in cannon, how produced, 208 ; 
 on the exterior, 211. 
 
 Crossbow, the ancient, 272. 
 
 Cuirass and helmet, description of, 286. 
 
 Curving plates for musket-barrels, 321. 
 
 Cuts in cannon, 210. 
 
 Cutting- arms, 282. 
 
 Cutting and filing in the manufacture of 
 small arms, 325. 
 
 Culverins, 106; very long one cast du- 
 ring the reign of Charles V., 127. 
 
 Cylinder and cap in ammunition, 352. 
 
 Cylinder-gauge, 201. 
 
 Cylinder-staff, 200 
 
 Cylindrical chambers, for fire-arms, 122 ; 
 injurious effect of* on heavy cannon, 
 123. 
 
 Dahlgren, Captain, two vents placed by, 
 in his naval guns, 209 ; experiments 
 of, in relation to deviation, 430. 
 
 Damascus steel, how made, 287. 
 
 Damask steel, appearance of, how pro- 
 duced, 142. 
 
 Dardanelles, defence of, by means of 
 stone projectiles, 72. 
 
 Decorations of signal rockets, 367. 
 
 Defects in parts of fire-arms, 337-339. 
 
 Defects of timber trees, 265. 
 
 Defensive armor, 286. 
 
 Defensive weapons, ancient, 272. 
 
 Definition of velocities of projectiles, 384. 
 
 Deflection of the Armstrong gun, 530. 
 
 Delvigne's improvements in loading rifles, 
 309. 
 
 Density of a charge of gunpowder of cy- 
 lindrical form, 62. 
 
 Density of gases developed in the com- 
 bustion of gunpowder, 58. 
 
 Density of gunpowder, influence of, on 
 the velocity of combustion, 43 ; in re- 
 lation to force, 56. 
 
 Derivation, or drift, causes of, 432. 
 
 Destruction of artillery, 259. 
 
 Determination of equations of motion. 
 395-400. 
 
 Deviation, 294. 424 ; conclusion respect- 
 ing the causes of, 429 ; of oblong pro- 
 jectiles, 431 ; effect of wind in produc- 
 ing, 433; summary of the causes of, 
 433; measure of, 460; vertical and 
 horizontal, 461; with the 15-inch co- 
 lumbiad, 532. 
 
 Devices on old cannon, 108. 
 
 Didion, Captain, on trajectory in the air, 
 412. 
 
 Different kinds of cannon, 166; small- 
 arms, 316: fires, 450. 
 
 Dimensions of siege mortars, 186; of the 
 siege howitzer, 186. 
 
 Direct fire, when used, 450. 
 
 Direct fire of field artillery, 490. 
 
 Disabling cannon, 260. 
 
 Discharging fire-arms, 435. 
 
 Dish of the artillery-carriage wheel, 221. 
 
 Dismounting arms by a soldier, 332 ; by 
 an armorer, 335. 
 
 Dispart of cannon, 116. 
 
 Distance of objects, how estimated, 446. 
 
 Distillation, charcoal made by, 16. 
 
 Drag-rope, 258. 
 
 Draught-harness of the artillery horse, 
 218. 
 
 Draught-horses, force exerted by, 213 ; 
 table relating to the force of, 214; or- 
 , dinary load per day for, 215. 
 
 Drift, or derivation, causes of, 432. 
 
 Drifts, for use in making fireworks, 358. 
 
 Drilling and tapping of musket-barrels, 
 323. 
 
 Driving the composition of rockets, 367. 
 
 Dry compositions for fireworks, 356. 
 
 Drying gunpowder, 25. 
 
 Ductility, a desirable quality in cannon 
 metal, 133. 
 
 Ductility of wrought iron, 144. 
 
 Dupont's gunpowder compared with Haz- 
 ard's, 534. 
 
 Durability of the musket-barrel, 339. 
 
 Dyer, Major, projectiles devised by, 170. 
 
 Early cannon, shape of, 1 04 ; construction 
 of, 105. 
 
 Earth, effect of projectiles on, 475; pen- 
 etrations of projectiles into, 479. 
 
 Eccentric handspike for sea-coast car- 
 riages, 257. 
 
 Eccentric projectiles, effect of rotation on, 
 427. 
 
 Eccentric turning, 324. 
 
 Eccentricity in projectiles a cause of ro- 
 tation, 425. 
 
 Eccentrometer, uses of the, 426. 
 
 Effective range of field artillery, 488. 
 
 Effect of fire in general, 459. 
 
 Effects of gunpowder, 35; projectiles, 471. 
 
 Elasticity of material for cannon, 132. 
 
 Elasticity, absence of, in cast-iron can- 
 non, 145. 
 
 Electro-ballistic machines, 389. 
 
 Electro-ballistic machine at West Point, 
 390-395. 
 
 Elevating arc of the sea-coast carriage, 
 245. 
 
INDEX. 
 
 541 
 
 Elevating-screw of the sea-coast carriage, 
 244. 
 
 Elongated bullets, proper charge of pow- 
 der for, 315. 
 
 Elongated projectile, advantages of, point- 
 ed out by Robins, 309. 
 
 Employment of field artillery, 488 ; siege 
 cannon, 493 ; sea-coast cannon, 502. 
 
 Endurance of cast-iron cannon, 211 ; of 
 the 15-inch columbiad, 533. 
 
 Enfilading and counter fires with siege 
 cannon. 494. 
 
 Enlargement of bore, how produced, 208. 
 
 Equations of motion, 406-409 ; determi- 
 nation of, 395-400. 
 
 Equipments and implements for artillery, 
 251. 
 
 Escape of gas from breech-loading arms, 
 302. 
 
 Etching on a sword-blade, 289. 
 
 Expanding bullets, present form of, 312. 
 
 Expanding projectiles, 169. 
 
 Experiments with gunpowder, 533. 
 
 Explosion of gunpowder, phenomenon of, 
 38. 
 
 Explosive force of gun-cotton, 70. 
 
 Exterior of cannon, 151 ; nomenclature 
 of 157. 
 
 Fabrication of projectiles, 88 ; of sword- 
 blades, 287. 
 
 Face of cannon, 115. 
 
 Fascines, pitched, for incendiary purposes, 
 374. 
 
 Fall of a projectile in the air, 404, 422. 
 
 Felling timber for artillery purposes, 264. 
 
 Field ammunition, 351. 
 
 Field artillery, range of, 462 ; employ- 
 ment of, 488. 
 
 Field cannon, how classified, 180; weight 
 of, 180; length of bore of, 180; charges 
 of, 181; material for, 181; the Napo- 
 leon, 182; rapidity of fire of, 449. 
 
 Field carriages, turning of, 232 ; charac- 
 teristics of, 234 ; varieties of, 234. 
 
 Field guns, ranges of, 516. 
 
 Field howitzers, range of shells fired 
 from, 492 ; ranges of, 517, 518. 
 
 Field limber, construction of the, 230. 
 
 Field rifle-gun, Rodman's (note), 182. 
 
 Field shells, uses and range of, 463 ; un- 
 der what circumstances to be used, 
 493. 
 
 Fillets of field guns, 115. 
 
 Filling shells, 355. 
 
 Fire-arms, important recent improve- 
 ments in, 113 ; shape of the chambers 
 of, 121 ; length of bore of, 127 ; max- 
 imum charge of, 130 ; recoil of, 130 ; 
 strongest near the bottom of the bore, 
 157 ; various modes of rifling, 168 ; 
 
 portable, 273, 290 ; loading, pointing, 
 and discharging, 435. 
 
 Fire-ball, for lighting up enemy's works, 
 373; use of, in attack or defence, 498. 
 
 Fire, preparations for communicating, 
 380. 
 
 Fire, tables of, 447 ; rapidity of, 448. 
 
 Fire in general, effect of, 459. 
 
 Fire of case-shot, in attack or defence, 
 496 ; of the siege howitzer, 497 ; of 
 mortars, 499. 
 
 Fire-stone, description, preparation and 
 use of, 370, 371. 
 
 Fireworks, proportions of nitre, charcoal, 
 and sulphur for, 42 ; mililary, 356 ; for 
 signals, 366; incendiary, 370; for light, 
 372-375; ornamental, 376; offensive 
 and defensive, 376. 
 
 Firing at night, 444. 
 
 Firing in breach, 496. 
 
 Firing to effect a breach, rules for, 484. 
 
 First reinforce, thickness of, 157. 
 
 Fixed ammunition, 353. 
 
 Flame in ornamental fireworks, 378. 
 
 Flats of portable fire-arms, 292. 
 
 Flight of projectiles, to determine time 
 of, 422. 
 
 Flint-lock, when introduced and discard- 
 ed, 276. 
 
 Foot artillery sword, 285. 
 
 Foot-boards of the field-limber, 232. 
 
 Force, loss of, from windage, 124 ; nature 
 of, to be restrained by cannon, 153. 
 
 Force of draught-horses, table relating to, 
 214. 
 
 Force of gunpowder, 55 ; relation be- 
 tween, and density, 56 ; when inflam- 
 mation is instantaneous, 58 ; when in- 
 flammation is not instantaneous, 60; 
 when inflammation is instantaneous or 
 progressive, 66. 
 
 Forces acting on a gun-carriage, 228. 
 
 "Forcing" projectiles into rifle-barrels, 
 307 
 
 Forge, travelling, description of, 236. 
 
 Forging a sword-blade, 287. 
 
 Fork of the field limber, 231. 
 
 Form of a table of fire, 448. 
 
 Form of cannon, 151. 
 
 Form of projectile, theory in relation to, 
 409 ; results of experiments in relation 
 to, 411. 
 
 Form of siege guns, 185. 
 
 Formula for initial velocity, 385. 
 
 French army bullets, 313. 
 
 French musket-barrel, durability of, 339. 
 
 Friction, the object of a carriage-wheel 
 to diminish, 221. 
 
 Friction-powder, composition of, 360. 
 
 Friction-tube for firing cannon, 359. 
 
 Front sight of portable fire-arms, 299. 
 
542 
 
 INDEX. 
 
 Funnel, for loading shells, 254. 
 Furnaces in laboratories, 343. 
 Furrows in cannon, how produced, 208. 
 Fuze instruments, 253. 
 Fuzes of the Armstrong projectile, 529. 
 Fuzes, percussion, concussion, and time, 
 360-366. 
 
 Galileo on the path of projectiles, 382. 
 
 Garrison and siege cannon, 184. 
 
 Gas, law of formation of, in the combus- 
 tion of gunpowder, 44, 46; table of 
 quantities of, developed from various 
 grains of , gunpowder, 48; loss of, by 
 the fuze-hole of a shell, 87 ; escape of, 
 from breech-loading arms, 302. 
 
 Gases developed in the combustion of 
 gunpowder, density of, 58. 
 
 Gauges for inspecting fire-arms, 336. 
 
 Gerbe, in ornamental fireworks, 377. 
 
 Gin, an instrument for raising cannon, 
 248. 
 
 Glazing gunpowder, 25. 
 
 Globe and telescopic sights of fire-arms, 
 299. 
 
 Gomer chamber of fire-arms, advantages 
 of, 123. 
 
 Graduation of rear-sights, 445. 
 
 Grain of various kinds of gunpowder, 27 ; 
 results of experiments on six sizes of, 
 67. 
 
 Grained powder and caked powder, 1 54. 
 
 Granulating gunpowder, 24. 
 
 Grape and canister, inspection of, 91. 
 
 Grape and canister firing, 468. 
 
 Grape-shot, how composed, 80. 
 
 Gray iron, characteristics of, 147. 
 
 Greener's rifle projectile, 311. 
 
 Grenades, 79. 
 
 Gribeauval's system of artillery, 111; his 
 method of attaching artillery horses, 
 217. 
 
 Grinding a sword-blade, 288; small-arms, 
 325. 
 
 Grommets or ring-wads, 355. 
 
 Grooved balls, 75. 
 
 Grooves, form of, in rifled fire-arms, 171 ; 
 comparative advantages of variable 
 and uniform, in rifled fire-arms, 173; 
 method of cutting, in cannon, 173; 
 number, width, and shape of, in can- 
 non, 174; inclination of, in rifled fire- 
 arms, 175, 179 ; objects to be attained 
 by, in rifles, 294 ; kind adopted by the 
 United States government, 295 ; rota- 
 tion produced by, in gun-barrels, 294. 
 
 Guard-bow of portable fire-arms, 300. 
 
 Guard-plate of portable fire-arms, 300. 
 
 Gum-arabic in pyrotechny, 347. 
 
 Gun-carriages, classification of, 225 ; im- 
 portant requisites of, 225 ; forces act- 
 
 ing on, 228 ; construction of, 234; sea- 
 coast, 243. 
 
 Gun-cotton, how prepared, 68 ; projectile 
 force of, 69 ; explosive force of, 70. 
 
 Gun metal, character of, 146 ; density 
 and tenacity of, 147. 
 
 Gun-pendulum, for determining veloci- 
 ties, 388. 
 
 Gun-platform, how constructed, 242. 
 
 Gunner, implements carried by, 254. 
 
 Gunnery, science of, 382. 
 
 Gunpowder, general theory of, 7 ; com- 
 position of, 8; manufacture of, 21, 23; 
 pressing and granulating, 24 ; simple 
 method of manufacturing, 25; glazing, 
 drying, and dusting, 25; general qual- 
 ities of good, 27 ; inspection and proof 
 of, 27; size of grain of various kinds 
 of, 27; specific gravity of, 28; mercu- 
 ry densimeter for, 28 ; initial velocity 
 of, 29; how packed, 30; inspection re- 
 port as to the qualities of, 30 ; quanti- 
 ty of charcoal in, 31 ; quantity of salt- 
 petre in, 31; hygrometric qualities of, 
 32 ; quantity of sulphur in, 32 ; quick- 
 ness of burning of, 33 ; unserviceable, 
 how restored, 33 ; storage and preser- 
 vation of, 34; history of, 35; transpor- 
 tation of, 35 ; effects of, 35 ; phenom- 
 enon of explosion of, 38 : ignition of, 
 38; combustion of, progressive, 40; 
 influence of purity and proportions of 
 ingredients on combustion, 41; influ- 
 ence of density of, on velocity of com- 
 bustion. 43 ; effects of trituration of in- 
 gredients, 43 ; velocity of combustion 
 of, increased by moistening and sub- 
 sequent drying, 44 ; law of formation 
 of gaseous products from, 44 ; combus- 
 tion of a spherical grain of, 45 ; com- 
 bustion of a polyhedral grain of, 46; 
 combustion of a grain of ordinary, 47 ; 
 inflammation of. 49 ; influence of the 
 size of the grain of, on combustion, 49 ; 
 velocity of inflammation of, diminished 
 by compression (note) 52 ; products of 
 the combustion of, 52 ; gaseous prod- 
 ucts resulting from the combustion of, 
 53 ; for war purposes, proportions of, 
 53; temperature of the gaseous pro- 
 ducts of, 54 ; determination of the force 
 of, 55 ; relation between the density 
 and force of, 56 ; density of the gases 
 developed in the combustion of, 58; 
 force of, when inflammation is instanta- 
 neous, 58 ; force of, when inflammation 
 is not instantaneous, 60 ; density of a 
 cylindrical charge of, 62 ; expansive 
 force of instantaneous or progressive 
 inflammation of, 66 ; results on veloci- 
 ty, of various densities of, 67 ; for prov- 
 
ITOEX. 
 
 543 
 
 ing cannon, 205 ; injuries to cannon 
 from, 203 ; in pyrotechny, 345 ; exper- 
 iments with, 533. 
 Guns, ancient, 106; distinguishing char- 
 acteristics of, 166; how proved, 206; 
 how pointed, 439; for sea-coast ser- 
 vice, 190; trajectory of projectiles of, 
 414-418. 
 
 Halberd, 271. 
 
 Hale's rocket, 98. 
 
 Hand-arms, ancient, 270; classification 
 of, 277 ; general principles of, 277. 
 
 Hand-grenade, 79; description of Ketch- 
 urn's (note), 80. 
 
 Handles of bronze field-pieces, 163. 
 
 Handling the sabre, 283. 
 
 Hardening and tempering steel, 326. 
 
 Hardness a necessary quality in cannon 
 metal, 137. 
 
 Hardness of wrought iron, 144. 
 
 Harness for artillery horses, 215. 
 
 Haversack, gunner's, for carrying cart- 
 ridges, 252. 
 
 Hazard's gunpowder compared with Du- 
 pont's, 534. 
 
 Head-gear of artillery horses, 218. 
 
 Heavy charges for cannon, 120. 
 
 Helmet and cuirass, description of, 286. 
 
 History of gunpowder, 35 ; of rockets, 
 102; of cannon, 104; of small-arms, 
 270; of ballistics, 382. 
 
 Hollow projectiles, cavities of, how made, 
 89; inspection of, 91, 92. 
 
 Hollow-shot, various denominations, 77. 
 
 Hotchkiss' rifle-projectile, 536. 
 
 Hot-shot, hay wads used for, 355 ; how 
 prepared and used, 372. 
 
 Hounds of the field limber, 231. 
 
 Howitzers, ancient, 107 ; characteristics 
 and uses of the, 166; for mountain 
 service, 183; for siege purposes, 186; 
 weight of, 180; for sea-coast service, 
 193; how proved, 206; how pointed, 
 439; trajectory of projectiles of, 414- 
 418 ; mountain, range of, 463. 
 
 Howitzer carriages, construction of, 234. 
 
 Hutton on the paths of projectiles. 383 ; 
 experiments of, in relation to the forms 
 of projectiles, 410. 
 
 Hygro metric qualities of gunpowder, 32. 
 
 Ignition of gunpowder, 38. 
 
 Implements and equipments for artillery, 
 251. 
 
 Incendiary fireworks, 370. 
 
 Incendiary match, how made, 372. 
 
 Inclination of grooves in rifled fire-arms, 
 175; limit of, 179. 
 
 Inclination most suitable for grooves in- 
 rifled fire-arms, 179. 
 
 Incompressible fluid, resistance of, 402. 
 
 Incorporating ingredients of gunpowder. 
 23. 
 
 Infantry, effect of field artillery against, 
 489. 
 
 Inflammation of gunpowder, 49 ; circum- 
 stances influencing the velocity of, 50; 
 force developed by instantaneous, 58 ; 
 force developed by, when not instan- 
 taneous, 60. 
 
 Ingredients of gunpowder, 21. 
 
 Initial velocity, of gunpowder, 29 ; of 
 projectile from rifled fire-arms, 174 
 with American small-arms, 316-319 
 of projectiles, 384; causes affecting, 
 387 ; formula for, 385 ; practical rule 
 for, 387 ; determination of, by experi- 
 ment, 388 ; of a mortar-shell, to find, 
 421 ; causes which affect, 424. 
 
 Initial velocities, table of, with service 
 charges, 387 ; tables of values for, 508, 
 514. 
 
 Injuries to cannon, caused by service, 
 207 ; from the projectile, 209. 
 
 Inspection of gunpowder, 27 ; of projec- 
 tiles, 90; of cannon, 200, 201; of 
 bronze cannon, 204 ; of sword-blades, 
 289; of small-arms, 327; of arms in 
 service, 336. 
 
 Inspection marks on cannon, 207. 
 
 Inspection report as to the qualities of 
 gunpowder, 30. 
 
 Instruments for the inspection of hollow 
 projectiles, 91 ; for the inspection of 
 cannon, 200. 
 
 Interchange of parts in similar arms, 
 320, 339. 
 
 Interior form of cannon, 116. 
 
 Iron cannon, how proved, 206. 
 
 Iron ores used by the United States 
 government for the manufacture of 
 cannon, 146. 
 
 Iron parts of a gun-carriage, 227. 
 
 Iron-plated ships, the smaller sea-coast 
 guns useless against, 189 ; effects of 
 projectiles on, 472. 
 
 Iron sling-cart, for moving cannon, 249. 
 
 Irreparable arms, 339. 
 
 James' rifle, dimensions of, 319 ; projec- 
 tile for, 536 
 Javelin, Roman, 271. 
 Jets, in movable fireworks, 379. 
 
 Knob of the cascable, 163. 
 
 Laboratory, military, how it should be 
 situated, 342 ; precautions to be used 
 in, 343. 
 
 Lackering projectiles, 93. 
 
 Ladle, for withdrawing projectiles, 252. 
 
544 
 
 INDEX. 
 
 Lampblack in pyrotechny, 346. 
 Lance, description of the, 279; advan- 
 tages of the use of the, 280 ; mode of 
 carrying on horseback, 280. 
 Lance, Macedonian, 270. 
 
 Lance, in ornamental fireworks, 377. 
 
 Land-batteries, advantages of, 502. 
 
 Large cannon for sea-coast batteries, 189. 
 
 Law of resistance, 402. 
 
 Lead, projectiles of, 72. 
 
 Length of barrel, of portable fire-arms, 
 294 ; influence of, on velocity of pro- 
 jectile, 294. 
 
 Length of bore, of fire-arms, influence 
 of, on velocity of projectile, 127 ; 
 effect of, on maximum charge, 131 ; 
 experiments to determine the influ- 
 ence of, 128 ; of field cannon, 180 ; of 
 siege guns, 185. 
 
 Length of projectiles, effect of, 175. 
 
 Length of stock of field carriages, 233. 
 
 Level, gunner's, description of, 254. 
 
 Lever-jack, 250. 
 
 Lifting-jack, 250. 
 
 Light-artillery sabre, description of, 284. 
 
 Light-balls, 374. 
 
 Light-barrel, how constructed, 376. 
 
 Light charges for cannon, 121. 
 
 Limber, object of the, 230 ; for siege 
 carriages, 240. 
 
 Limbering, difficulty of the old system 
 of, 232. 
 
 Line of fire, definition of, 437. 
 
 Line of sight, definition of, 436. 
 
 Liquid compositions for fireworks, 356. 
 
 Load of pack-horses, 213; of artillery 
 horses, 215; of field carriages, 233. 
 
 Loading Armstrong gun, 529. 
 
 Loading cannon, implements for, 251. 
 
 Loading fire-arms, 435; improvements 
 in, 276. 
 
 Loading rifles, various modes of, 307. 
 
 Lock of a portable fire-arm, 295 ; con- 
 ditions to be fulfilled in the construc- 
 tion of, 296 ; inspection of, 330 ; de- 
 fects in, 338. 
 
 Lock of a rifle-musket, how cleaned, 334 ; 
 how taken apart, 335. 
 
 Locking wheels of artillery carriages, 
 233. 
 
 Lodgement, injury to cannon caused by, 
 209 ; means used to prevent, 210. 
 
 Longitudinal strain upon cannon, 154. 
 
 Long ranges of siege cannon, 493. 
 
 Loss of velocity by resistance of the air, 
 406. 
 
 Louis Napoleon's system of artillery, 
 112. 
 
 Lubricant for fire-arms, 315. 
 
 Macedonian lance, 270. 
 
 Machines and implements for artillery, 
 248. 
 
 Magnus, Prof, apparatus devised by, 
 428. 
 
 Mallet's monster mortar, how construct- 
 ed, 150. 
 
 Manoeuvre of artillery carriages, imple- 
 ments for, 256 ; of the 15-inch colum- 
 biad, 533. 
 
 Manoeuvring handspike for sea-coast 
 carriages, 257. 
 
 Manufacture of cannon, 194; of small- 
 arms, 320; of sword-blades, 287. 
 
 Marks, inspection, on cannon, 207. 
 
 Marrons in signal rockets, 369. 
 
 Martello tower, rapid destruction of one 
 with rifle projectiles, 485. 
 
 Masonry, effect of projectiles on, 480. 
 
 Matchlock, description of the, 274. 
 
 Materials for the fabrication of cannon, 
 138 ; for field cannon, 181 ; for sea- 
 coast carriages, 243 ; for artillery car- 
 riages, 261-266; for pyrotechny, 344- 
 348. 
 
 Materiel of artillery, 108. 
 
 Maximum charge of fire-arms, 130. 
 
 Maynard musket, description of, 306. 
 
 Maynard's primer, how made, 350. 
 
 Maynard's self-priming percussion lock, 
 297. 
 
 Maynard's system of " packing the joint" 
 of breech-loading arms, 304. 
 
 "Mealed powder," 37 ; in pyrotechny, 
 345. 
 
 Measure of deviation, 460. 
 
 Measures, for charges of powder, 254. 
 
 Mechanical principles determining initial 
 velocities, 384. 
 
 Men's harness, 258. 
 
 Mercury densimeter for gunpowder, 28. 
 
 Metal for cannon, qualities desirable in, 
 132 ; the various kinds used, 138. 
 
 Military fireworks, 356. 
 
 Mill-cake, pressing, 24. 
 
 Milling, in the manufacture of small-arms, 
 324. 
 
 Minie, form of projectile proposed by, 
 309; his rifle projectile, 311. 
 
 Model, wooden, for moulding cannon, 
 195. 
 
 Models for ordnance materiel, 268. 
 
 Molten iron used for incendiary purposes 
 {note), 372. 
 
 Momentary effort exerted by draught- 
 horses, 214. 
 
 Mordecai. Major, results of experiments 
 of, with gun-cotton, 69 ; experiments 
 of, on the influence of length of bore, 
 129. 
 
 Mortar, nitre obtained from, 12. 
 
 Mortar, a term applied to early cannon, 
 
INDEX. 
 
 545 
 
 104 ; ancient, 1 06 ; characteristics and 
 uses of, 16 7-; for siege purposes, 186; 
 form of, adopted in 1861, 187 ; spheri- 
 cal case-shot, for, 188 ; how proved, 
 206 ; inspection of, 204 ; how pointed, 
 442 ; fire of, in attack or defence, 499 ; 
 case-shot fire of, in attack or defence, 
 501 ; uncertainty of the fire of, from 
 shipboard, 504. 
 
 Mortar-fuze, description of the, 361. 
 
 Mortar-platform, how constructed, 242. 
 
 Mortar-scraper, 254. 
 
 Mortar-shells, 79 ; bursting-charge of, 
 355 ; table of times of flight of, 401 ; 
 table of ranges of, 401 ; to find the 
 initial velocity of, 42 i ; how fired, 436 ; 
 fire of, 464. 
 
 Mortar-wagon for siege purposes, 240. 
 
 Motion, equations of, 406, 409. 
 
 Motion of rockets, 95, 96 ; of a projectile 
 in vacuo, 395. 
 
 Mottled iron, characteristics of, 148. 
 
 Mould for casting cannon, how formed, 
 196. 
 
 Moulding cannon, process of, 195. 
 
 Mountain ammunition, 351. 
 
 Mountain cannon, 183. 
 
 Mountain howitzer, 183 ; ranges of, 517. 
 
 Mountain howitzer carriage, requisites 
 of, 237 ; description of, 238. 
 
 Mountain shells, range of, 463. 
 
 Mountings of portable fire-arms, 300 ; 
 inspection of, 330. 
 
 Mountings of rifle-musket, how cleaned, 
 334. 
 
 Movable pieces of fireworks, 378. 
 
 Mules as pack-animals, 213. 
 
 Multipliers, tables of, 505. 
 
 Musket, introduced by Charles V, 274; 
 description of Maynard's, 306 ; boxes 
 for packing, 330. 
 
 Musket-barrels, how made, 321 ; how 
 browned, 327 ; defects in, 337 ; dur- 
 ability of, 339 ; strength of, 340. 
 
 Mutzig, trials made at, as to the strength 
 . of musket-barrels, 340. 
 
 Muzzle of cannon, 116; enlargement of, 
 210. 
 
 Nail-ball, 75. 
 
 Napoleon field-gun, description of, 182 ; 
 advantages and disadvantages of, 183. 
 
 Natural angle of sight, 116, 181; of siege- 
 mortars, 187. 
 
 Natural line of sight on cannon, how 
 marked, 207. 
 
 Natural point-blank, definition of, 438. 
 
 Natural steel, 140. 
 
 Nave-box of the artillery carriage, 227. 
 
 Navez, Captain, ballistic machine of, 389. 
 
 Neck of cannon, 115. 
 35 
 
 Newton on the path of projectiles, 382. 
 
 Night-firing, 444. 
 
 Nitrate of soda, 15. 
 
 Nitre, preservation of, 12 ; refining of, 
 12 ; for laboratory use, 344. 
 
 Nitre-beds, how made, 11. 
 
 Nomenclature of artillery carriages, 225; 
 of cannon of old pattern, 114 ; of artil- 
 lery carriage- wheels, 220 ; of portable 
 fire-arms, 291 ; of a percussion lock, 
 296. 
 
 Oak, effect of projectiles on, 474, 481. 
 
 Objects, distance of, how estimated, 446. 
 
 Oblong bullet, description of, used in the 
 United States service, 77. 
 
 Oblong projectiles, superiority of, 74; 
 trajectory of, 423 ; deviation of, 431. 
 
 Offensive and defensive fireworks, 376. 
 
 Ordnance and ordnance stores, what con- 
 stitute, 108. 
 
 Ores of iron, used for the manufacture of 
 cannon, 146. 
 
 Ornamental fireworks, 376. 
 
 Pack-horse, work of, to be regulated, 212. 
 Packing gunpowder, 30 ; arms, 330 ; 
 
 small-arm cartridges, 349. 
 "Packing the joint" of breech-loading 
 
 arms, 302. 
 Painting artillery carriages, 268. 
 Paper, laboratory, classes of, 347. 
 Paper shells, how made, 380. 
 Parrott rifle-gun, how constructed (note), 
 
 150 ; how mounted (note), 234 ; ranges 
 
 of, 522. 
 Parrott's rifle projectile, 535. 
 Pass-box, for carrying cartridges, 252. 
 Patch, mode of using with rifles, 308. 
 Pattern for moulding cannon, 195. 
 Pendulum hausse, how used, 255. 
 Penetration of projectiles, 476; of the 
 
 rifle-musket bullet, 486. 
 Percussion bullets, how made, 83. 
 Percussion caps, description of, 350. 
 Percussion fuze, description of, 365. 
 Percussion lock, nomenclature of, 296. 
 Perriere, an early form of cannon, 105. 
 Petard, explosive, thrown aside, 376. 
 ■Petard, in ornamental fireworks, 377. 
 Petronel, description of the, 274. 
 Pig-iron, character of, 146 ; density and 
 
 tenacity of, 147. 
 Pike, the ancient, 270. 
 Piling of cannon-balls, 93. 
 Pintle, the centre of the chassis of sea- 
 coast gun-carriages, 246. 
 Pintle-hook of the field-limber, 232. 
 Pistol, when and where invented, 274. 
 Pistol-carbine, description of, 318. 
 Pistol cartridge, how made, 350. 
 
546 
 
 INDEX. 
 
 Pitch in pyrotechny, 347. 
 
 Pitched fascines, for incendiary purposes, 
 374. 
 
 Plane of fire, definition of, 437. 
 
 Plane of rupture of shells, 84. 
 
 Plane of sight, definition of, 437. 
 
 Platforms of siege pieces, how construct- 
 ed, 241. 
 
 Plunging-fire, 459. 
 
 Point-blank, definition of, 437. 
 
 Pointing fire-arms, 435. 
 
 Pointing guns, implements for, 254. 
 
 Pointing small-arms, 445. 
 
 Pole of the field-limber, 231. 
 
 Polishing a sword-blade, 289 ; small- 
 arms, 325. 
 
 Poplar, charcoal for gunpowder made 
 from, 15. 
 
 Portable fire-arms, 290 ; early history of, 
 273 ; calibre of, 293. 
 
 Port-fires, composition of, 359. 
 
 Position of the centre of gravity of pro- 
 jectiles, 178. 
 
 Pot of signal-rockets, 367. 
 
 Potassa, chlorate of, used in the manu- 
 facture of gunpowder, 14; in pyro- 
 techny, 344. 
 
 Powder, proper charge of, for elongated 
 bullets, 314; see Gunpowder. 
 
 Powder, round, 25. 
 
 Powder-proof of cannon, 205. 
 
 Practical rule for initial velocity, 387. 
 
 Prairie artillery carriage, description of, 
 238. 
 
 Prairie-cannon, 183. 
 
 Precaution in using fire-arms, 336; against 
 accidents in pyrotechny, 343 ; in load- 
 ing cannon, 435. 
 
 Preponderance of cannon, 161 ; mortars 
 and columbiads now made without 
 (note), 162; of the siege-howitzer, 186. 
 
 Preservation of gunpowder. 34 ; of can- 
 non-balls, 93 ; of artillery harness, 219; 
 of artillery carriages, 259 ; of timber, 
 265 ; of arms in service, 332. 
 
 Pressure in the bore of the 15-inch col- 
 umbiad, 532. 
 
 Priming-wire, for pricking cartridges, 
 253. 
 
 Pritchett bullet, how made, 313. 
 
 Projectile arms, ancient, 271. 
 
 Projectile force of gun-cotton, 69. 
 
 Projectiles, materials of, 71 ; advantages 
 of spherical, 73 ; centre of gravity of, 
 74 ; oblong, superiority of the form of, 
 74 ; solid, for what purposes adapted, 
 75 ; fabrication of, 88 ; hollow, cavi- 
 ties of, how made, 89 ; inspection of, 
 90 ; maximum velocity of, on what de- 
 pendent, 129; proportion of, to weight 
 of charge, 131 ; with flanges, for rifles, 
 
 168; constructed on an expanding 
 principle, 169; effect of length of, 175; 
 influence of the resistance of the air 
 upon, 177; effect of the position of the 
 centre of gravity of, 178; shells and 
 hot-shot the best for sea-coast bat- 
 teries, 189; injuries to cannon from, 
 209 ; for small-arms, 307 ; of the Whit- 
 worth rifle, 311 ; initial velocity of, 
 383 ; fall of, in the air, 404 ; theory in 
 relation to the form of, 409 ; oblong, 
 trajectory of, 423 ; deviation of, 424 ; 
 concentric, effect of rotation on, 427 ; 
 eccentric, effect of rotation on, 427 ; 
 oblong, deviation of, 431 ; smaller 
 than the bore, how used, 435 ; effects 
 of, 471 ; of the Armstrong gun, 528. 
 
 Projections, omitted on the surface of 
 cannon of late construction, 160. 
 
 Prolonge, a stout hempen rope, 258. 
 
 Proof of gunpowder, 27 ; of cannon, 205 ; 
 of sword-blades, 289 ; of scabbard, 
 290. 
 
 Properties of bronze, 139; of steel, 142. 
 
 Props of chassis rails, 247. 
 
 Puddled steel, how obtained, 142. 
 
 Pulverizing charcoal, 23. 
 
 Pyrotechny, definition of, 342 ; buildings 
 for, 342 ; precautions against accidents 
 in, 343 ; materials for, 344-348. 
 
 Pyroxile, or gun-cotton, 68. 
 
 Quadrant, gunner's, 256. 
 Queen Anne's pocket-piece, 106. 
 Quick-match, description of, 359. 
 
 Rail platform, how constructed, 242. 
 
 Rammer-head used in the inspection of 
 cannon, 201. 
 
 Rammer-head for loading cannon, 251 
 
 Rampart grenade, 79. 
 
 Ramrods of portable fire-arms, 301 ; in- 
 spection of, 329. 
 
 Range, to determine, 422 ; definition of, 
 439. 
 
 Range of field artillery, 462, 463, 488 ; 
 of siege-cannon, 493 ; of the Arm- 
 strong projectile, 530 ; of artillery, 
 516-523. 
 
 Ranges, table of values for calculation of, 
 507, 513. 
 
 Ranges of mortar-shells, table of, 401. 
 
 Ranges obtained with Captain Rodman's 
 15-inch columbiad, 532. 
 
 Rapidity of fire, 448. 
 
 Rear-sight of portable fire-arms, 299 ; 
 aiming without, 300. 
 
 Rear-sights, graduation of, 445. 
 
 Recoil, increase of, greater than increase 
 of charge, 130 ; diminished by appli- 
 cation of weights, 137. 
 
INDEX. 
 
 547 
 
 Reinforce of cannon, 115. 
 
 Rejected cannon, how marked, 207. 
 
 Repairs of artillery carriages, 259. 
 
 Resistance of the air, 402 ; effect of, on 
 a rifle-projectile, 177 ; loss of velocity 
 by, 406. 
 
 Retempering a sword-blade, 288. 
 
 Ricochet fire, 450 ; when used, 452 ; 
 practical rules for, 453 ; of field artil- 
 lery, 492 ; of sea-coast batteries, 504. 
 
 Ricochet firing, cartridge bag for, 354. 
 
 Rifle-cannon, hardness of metal neces- 
 sary to, 137 ; definition of, 167 ; 
 breaching with, 485. 
 
 Rifled fire-arms, form of groove of, 171 ; 
 variable groove of, 172; limit of incli- 
 nation of grooves in, 179. 
 
 Rifle-grooves, points to be observed in 
 constructing, 294. 
 
 Rifle-guns, ranges of, 522. 
 
 Rifle-musket, description of the, 316; how 
 dismounted, 332 ; trials of strength of, 
 340 ; cartridge, 349 ; bullet, penetra- 
 tions of, 486. 
 
 Rifle-projectiles, different systems of, 535. 
 
 Rifle siege-gun, description of (note), 184. 
 
 Rifles, how classified, 168; invention and 
 history of the, 275 ; original mode of 
 loading, 308; as distinguished from 
 the rifle-musket, 317 ; American sport- 
 ing, 319. 
 
 Rimbases of cannon, 116 ; description of, 
 162. 
 
 Robins, elongated projectiles proposed 
 by, 309 ; on the path of projectiles, 
 383 ; deviation by rotation discovered 
 by, 431. 
 
 Rockets, theory and construction of, 94 ; 
 motion of, 95 ; origin of movement in, 
 96; guidiug principle of, 97; Hale's 
 system for guiding, 98; Congreve's sys- 
 tem for guiding, 99 ; how fired, 99 ; 
 signal and war, 99 ; form of trajectory 
 of, 100 ; effect of wind on the trajec- 
 tory of, 101 ; history of, 102 ; advan- 
 tages claimed for, over cannon, 102 ; 
 kinds used in the United States ser- 
 vice, 103; signal, principal parts of, 
 366. 
 
 Rodman, Captain, experiments of, with 
 cake-powder (note), 49 ; experiments 
 of, in relation to the density of gases 
 (note), 58 ; plan of, for cooling cannon 
 from the interior, 136 ; plan of, for de- 
 termining the force of the charge in 
 fire-arms, 152 ; experiments of, on the 
 force of cake and grained powder (note), 
 153 ; his formula for calculating the 
 exterior form of large cannon (note), 
 157 ; great improvements of, in cast- 
 ing large guns, 531. 
 
 Roller handspike, for new sea-coast car- 
 riages, 257. 
 
 Rolling fire, 458. 
 
 Rolling friction, 223. 
 
 Rolling musket-barrels, 321. 
 
 Roman candles, how made, 380. 
 
 Rope matting impenetrable to small-arm 
 projectiles, 487. 
 
 Rosin in pyrotechny, 347. 
 
 Rotation, initial velocity of, in rifle-pro- 
 jectiles, 174; a principal cause of de- 
 viation of projectiles, 425 ; effect of, 
 in producing deviation, 427; of the 
 earth, influence of, in producing devia- 
 tion, 434. 
 
 Round bullets, denomination of, 76. 
 
 Round powder, how made, 25. 
 
 Rules for firing to effect a breach, 484. 
 
 Rules for ricochet fire, 453. 
 
 Rumford, Count, experiments of, on the 
 combustion of gunpowder, 54 ; eprou- 
 vette used by, for determining the 
 force of gunpowder, 55. 
 
 Rupture of cannon, tendency to, greatest 
 from tangential force, 156. 
 
 Rupture of shells, 84. 
 
 Sabot, description of the, 351. 
 
 Sabre, the ancient, 271; best construc- 
 tion of for handling, 283 ; description 
 of, 284. 
 
 Saddle of the artillery horse, 218. 
 
 Saltpetre, description of, 9 ; whence ob- 
 tained, 10; test of rough, 13; test of 
 pure, 14 ; quantity of, in gunpowder, 
 31. 
 
 Sand, the best kind for moulding cannon, 
 196. 
 
 Sarissa, or Macedonian lance, 270. 
 
 Sawyer's rifle-projectile, 536. 
 
 Saxon, in movable fireworks, 379. 
 
 Scabbard, uses and material of the, 285 ; 
 proof of, 290. 
 
 Schenck's rifle-projectile, 536. 
 
 Schonbein, Prof., gun-cotton discovered 
 by, 68. 
 
 Schwartz, Berthold, explosive properties 
 of gunpowder discovered by, 36. 
 
 Science of gunnery, 382. 
 
 Scratches in cannon, 210. 
 
 Screw-jack, used in greasing carriage 
 wheels, 259. 
 
 Sea-coast ammunition, 353. 
 
 Sea-coast cannon, 188 ; various kinds of, 
 190 ; rapidity of fire of, 449 ; employ- 
 ment of, 502. 
 
 Sea-coast carriages, classification of, 243 ; 
 various kinds of, 247. 
 
 Sea-coast defence, fires advantageous in, 
 503. 
 
 Sea-coast fuze, description of, 363. 
 
548 
 
 INDEX. 
 
 Sea-coast gun-carriages, 243. 
 
 Sea-coast guns, ranges of, 519. 
 
 Sea-coast howitzers, description of, 193 ; 
 ranges of, 519. 
 
 Sea-coast howitzer shell, 79. 
 
 Sea-coast mortars, description of, 193; 
 the new (note), 194; range of, 521; 
 ranges with the 13-inch, 523. 
 
 Sea-coast shells, range and force of, 464. 
 
 Searcher, 201. 
 
 Seasoning and preserving timber, 265. 
 
 Seat of the charge of cannon, 120. 
 
 Second reinforce, thickness of, 158. 
 
 Self-priming percussion-lock, Maynard's, 
 297. 
 
 Serpents, in fireworks, how composed, 
 368. 
 
 Sharp's system of " packing the joint" of 
 breech-loading arms, 303. 
 
 Shear-steel, various kinds of, 141. 
 
 Shell-hooks, 254. 
 
 Shell-plug screw, 253. 
 
 Shells, material and denomination of, 77; 
 spherical, description of, 78; charge 
 of rupture of, 84 ; loss of gas by the 
 the fuze-holes of, 87 ; strapped to 
 sabots, 354; service bursting-charges 
 of, 355 ; loaded as carcasses. 372 ; 
 paper, how made, 380 ; French mor- 
 tar, table of times of flight of, 401 ; 
 force and range of, 463. 
 
 Shod handspike, for mortars, 257. 
 
 Shot, inspection of, 90 ; for proving can- 
 non, 206 ; wedged in cannon, how 
 drawn out, 261. 
 
 Shrapnel, Colonel, spherical case-shot 
 perfected by, 82. 
 
 Shrapnel firing, 465. 
 
 Siege and sea-coast ammunition, 353. 
 
 Siege-cannon, 184; rapidity of fire of, 
 449 ; employment of, 493. 
 
 Siege-carriages, various kinds of, 239. 
 
 Siege gun-carriage, construction of, 239. 
 
 Siege-guns, characteristics of, 184; 
 ranges of, 518. 
 
 Siege-howitzer, description of, 186 ; fire 
 of, in attack or defence, 497 ; ranges 
 of, 519. 
 
 Siege-mortars, description of, 186; bed, 
 how constructed, 241 ; ranges of, 521. 
 
 Siege-shells, uses of, 464. 
 
 Sights of portable fire-arms, 298. 
 
 Signal-rockets, 99 ; principal parts of, 
 366. 
 
 Signals, fireworks for, 366 
 
 Sinope, destruction of the Turkish fleet 
 at, by Russian shells, 189. 
 
 Skelp of a sword-blade, 287. 
 
 Sky-rockets, 378. 
 
 Sleeves, gunner's, 254 
 
 Sling, the ancient, 271. 
 
 Sling-carts, wooden and iron, 249 
 
 Slow-match, description of, 358. 
 
 Small-arm firing, 469. 
 
 Small-arm projectiles, 307. 
 
 Small-arms, classification of, 268 ; charge 
 of powder for, 314; different kinds of, 
 316 ; manufacture of, 320 ; inspection 
 of, 327; ammunition for, 348; trajec- 
 tory of projectiles of, 414, 418 ; rapidi- 
 ty of fire of, 449 ; how pointed, 445. 
 
 Soda, nitrate of, 15. 
 
 Solid-shot, classification of, 75 ; penetra- 
 tions of, 478 ; when broken, 478, 481 
 
 Solid-shot firing, 462. 
 
 Solubility of nitre, 9. 
 
 Sparks in fireworks, how produced, 346. 
 
 Spherical case-shot, description of, 82 ; 
 fabrication of, 88; for mortars, 188; 
 late improvements in, 466 ; effect of, 
 from rifle-cannon, 467. 
 
 Spherical chamber of fire-arms, 123. 
 
 Spherical projectiles, advantages of, 73 
 
 Spherical shells, description of, 78. 
 
 Spiking cannon, process of, 260. 
 
 Spirits of turpentine in pyrotechny, 347 
 
 Splinter-bar of the field-limber, 231. 
 
 Sponge, for cleaning out cannon, 251. 
 
 Sponge-bucket, for washing bore of can- 
 non, 258. 
 
 Spontoon, or half-pike, 271. 
 
 Sporting rifle, American, 319 
 
 Springfield, Mass., United States armory 
 at, 320. 
 
 Sprue, used in casting cannon, 196. 
 
 Stand of ammunition, how composed, 
 351. 
 
 Star-gauge, 200. 
 
 Stars of signal rockets, 367 
 
 Steamer Princeton, why the large wrought 
 iron gun burst on, 144. 
 
 Steel as a material for cannon. 139; 
 characteristics of, 140; properties of, 
 142 ; Damascus, how made, 287 ; how 
 hardened and tempered, 326. 
 
 Steel plates and iron, comparative resist- 
 ance of, to projectiles, 474. 
 
 Stick of signal-rockets, 369. 
 
 Stock of an artillery carriage, 225. 
 
 Stock of portable fire-arms, 298; defects 
 in, 338; inspection of, 329. 
 
 Stock trail system of artillery, 112. 
 
 Stone mortar, uses and dimensions of. 
 187; charge of, 465. 
 
 Stone projectiles, 71. 
 
 Storage of gunpowder, 34; arms, 331. 
 
 Storehouse for artillery harness, 219. 
 
 Straightening plates of musket-barrels, 
 321. 
 
 Straight sword, parts of, 278. 
 
 Strain upon cannon, various kinds of, 
 154. 
 
INDEX. 
 
 549 
 
 Strapped ammunition, 353. 
 
 Strapping shells described, 354. 
 
 Straps of a stand of ammunition, 352. 
 
 Strength of cannon, effect of form of 
 chamber on, 124. 
 
 Strength of material of cannon, 132, 134. 
 
 Strength of musket-barrels, 340. 
 
 Strength of wrought iron, 143. 
 
 Structure of rockets, 94. 
 
 Sulphur, purification of, 20 ; properties 
 of, 20 ; quantity of. in gunpowder, 32 ; 
 the tenacity of cast-iron destroyed by, 
 149 ; in pyrotechny, 345. 
 
 Sulphuret of antimony in pyrotechny, 
 345. 
 
 System of artillery, 108. 
 
 Swaging, in the process of making mus- 
 ket-barrels, 323. 
 
 Sweden, peculiar form of cast-iron can- 
 non cast in, 159. 
 
 Swell of the muzzle of cannon, 115; 
 thickness of, 159. 
 
 Swiss service bullet, 314. 
 
 Sword, the ancient, 271. 
 
 Sword, the straight, parts of, 278. 
 
 Sword-bayonet, description and uses of 
 the, 281. 
 
 Sword-blades, manufacture of, 287. 
 
 Table of initial velocities with service- 
 charges, 387. 
 
 Tables of fire, 51 G; purpose of, 447. 
 
 Tables of multipliers, 505. 
 
 Tangential strain upon cannon, 154. 
 
 Tangent-scale, how used in pointing 
 guns, 255. 
 
 Tar in pyrotechny. 347. 
 
 Tar-bucket, for carrying grease, 258. 
 
 Targets, construction of. 461. 
 
 Tarred-links, how made and used, 374. 
 
 Tartaglia on the path of projectiles, 382. 
 
 Telescopic sights of fire-arms, 299. 
 
 Temperature, importance of, in the manu- 
 facture of charcoal, 17. 
 
 Temperature of the gaseous products of 
 gunpowder, 54. 
 
 Tempering steel, 326. 
 
 Tempering sword-blades, 287. 
 
 Tenacity of bronze, 139. 
 
 Tenacity of puddled steel, 142. 
 
 Theory and construction of rockets, 94. 
 
 Thickness of the metal of cannon, 151. 
 
 Thouvenin, form of projectile proposed 
 by, 309. 
 
 Thrusting arms, 277, 284. 
 
 Thumbstall, for closing vent, 253. 
 
 Tige, or spindle, of Colonel Thouvenin, 
 310. 
 
 Tilted steel, 141. 
 
 Timber, for artillery carriages, 261-266; 
 seasoning and preserving, 265. 
 
 Time-fuze, description of, 360. 
 
 Times, table of, for West Point ballistic 
 machine, 515. 
 
 Tin, bronze cannon injured by the melt- 
 ing of the, 139. 
 
 Torches, preparation and use of, 375. 
 
 Tourbillion, description of the, 379. 
 
 Track of field carriages, 233. 
 
 Trail handspike for field carriages, 256. 
 
 Trajectory of rockets, 100 ; of projectiles, 
 ancient theory respecting, 382 ; in the 
 air, 412-424; under high angles of 
 projection, 420; of oblong projectiles, 
 423 ; true and calculated, 423. 
 
 Transportation of gunpowder, 35. 
 
 Transverse strain upon cannon, 155. 
 
 Travelling-forge, description of, 236. 
 
 Treadwell, Prof., plan of, for combining 
 wrought-iron and cast-iron in cannon, 
 150. 
 
 Trees, selection of, for timber for artil- 
 lery purposes, 263 ; defects of timber, 
 265. 
 
 Trench cart, for use in trenches, 251. 
 
 Trigger of portable fire-arms, 300. 
 
 Trituration, influence of, on the combus- 
 tibility of charcoal, 19; effect of, on 
 the ingredients of gunpowder, 43. 
 
 Trunnion-gauge, 201. 
 
 Trunnion- rule, 201. 
 
 Trunnion-square, 201. 
 
 Trunnions of cannon, 115; description of, 
 160 ; influence of position of, on recoil, 
 160; size of, dependent on recoil, 160; 
 importance of position of, on siege and 
 sea-coast cannon, 162 ; verification of 
 the axis of, 203. 
 
 Trunnions of the siege-howitzer, 186. 
 
 Truck for moving cannon in casemates, 
 250. 
 
 Truck handspike, for sea-coast carriages, 
 257. 
 
 Tube-pouch, worn by a cannonier, 252. 
 
 Turning cannon, 199; musket-barrels, 
 324. 
 
 Turning of field-carriages, 232. 
 
 Turpentine in pyrotechny, 346. 
 
 Twist, the inclination of a rifle-groove, 
 171. 
 
 Uniform groove in rifled fire-arms, 171. 
 United States service bullet, 312. 
 Unspiking cannon, process of, 261. 
 Uses to which cannon are applied, 180. 
 
 Valiere's system of artillery, 110. 
 Values, tables of, 510-514. 
 Variable groove in rifled fire-arms, 172. 
 Vauban's method of breaching walls, 482. 
 Velocities and times, tables of values of, 
 129, 512. 
 
550 
 
 INDEX. 
 
 Velocity, initial, of projectiles, 383 ; maxi- 
 mum of, dependent on what, 129 ; loss 
 of, by resistance of the air, 406 ; causes 
 affecting, 424. 
 
 Velocity of combustion of gunpowder, 39. 
 
 Venice turpentine in pyrotechny, 347. 
 
 Vent, small loss of force by the escape 
 of gas through, 119 ; table illustrating 
 influence of position of, 119. 
 
 Vent of Armstrong gun, 528. 
 
 Vent of cannon, position of, 117; size 
 of, 117; how bored 200; inspection 
 of, .204; wear of, how obviated, 208. 
 
 Vent of fireworks, 358. 
 
 Vent of rockets, 95. 
 
 Vent-gauges, 201. 
 
 Vent-piece, copper, adopted for rifle-guns 
 (note), 117. 
 
 Vent-searcher, 201. 
 
 Vertical field of fire of field-guns, 181 ; 
 of siege-guns, 185 ; of siege-mortars, 
 187 ; of the new columbiad, 192. 
 
 Wade, Major, experiments of, with eccen- 
 tric shells, 430. 
 
 "Wads (junk, hay and ring), how used, 
 355. 
 
 "Wagon, battery, 236. 
 
 "War-club, ancient, 270. 
 
 "War-powder, proportions of ingredients 
 of, in the United States service, 53. 
 
 War-rockets, 99. 
 
 "Water, penetration of projectiles into, 
 480. 
 
 "Watering bucket, artillery, 258. 
 
 "Weapons, ancient defensive, 272. 
 
 "Weight, recoil diminished by, 137. 
 
 Weight of American small-arms, 316- 
 319. 
 
 "Weight of barrel of portable fire-arms, 
 291. 
 
 "Weight of cannon, how determined, 165. 
 
 Weight of field-guns and howitzers, 180. 
 
 Weight of projectile and powder of 
 American small-arms, 316-319. 
 
 Weight of siege-guns, 185. 
 
 Welding, description of the process of, 
 321. 
 
 "Welding plates for musket-barrels, 321. 
 
 "West Point ballistic machine, 390-395; 
 table of times calculated for, 515. 
 
 Wheels of artillery carriages, names of 
 parts of, 220; objects of, 221; influ- 
 ence of size of, 224; greased and un- 
 greased, 227; should be of the same 
 height, 233. 
 
 "Wheels of gun-carriages, weight of, 224; 
 should be few kinds of, 224. 
 
 White iron, characteristics of, 14 8. 
 
 White pine, effect of projectiles on, 475. 
 
 Whitworth rifle, method of loading, 311. 
 
 Willow, charcoal for gunpowder made 
 from, 15. 
 
 Wind, deviation caused by, 433 ; effect 
 of, on the trajectory of rockets, 101. 
 
 Windage, loss offeree from, 124. 
 
 Wood, effect of projectiles on, 474 ; pene- 
 trations of projectiles into, 479. 
 
 Wootz, a natural steel from India, 140. 
 
 Worm, for withdrawing cartridges, 252. 
 
 Wounds made by thrusting-swords, 279. 
 
 Wrought-iron, projectiles of, 72; as a 
 material for cannon, 143 ; for artillery 
 carriages, 266; effect of projectiles on, 
 472. 
 
 Wrought-iron cannon made by the Phoe- 
 nix Iron Co. (note), 144. 
 
 Yataghan of the Arabs, 283. 
 
 Zorndorf, effect of a field-cannon ball at 
 the battle of, 487. 
 
Ti 
 

 
 
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