NOTES ON ARTILLERY: ROBINS, HUTTON, CHESNEY, MORDECAI, DAHLGREEN, II ' JACOB, GREENER, GIBBON AND BENTON. BT W. LEROY BROUN, M. A., Lieutenant Artillery, Virginia Volunteers. mOHMOND: PUBLISHED BY WEST & JOHNSTON, 145 MAIN STREET. 1862. %^> NOTES ON ARTILLERY. » NOTES ON ARTILLERY: FROM ROBINS, BUTTON, CHESNEY, MORDECAI, DAHLGREEN, JACOB, GREENER, GIBBON AND BENTON. BY W. LEROY BROUN, M.A., Lieutonant Artillerj Virginia Voluateers. RICHMOND: PUBLISHED BY WEST & JOHNSTON, 145 MAIN STREET 1862. •l! Entered according to act of Congress, in the year 1862, ^ By west & JOHNSTON, In the Clerk's Office of the District Court of the Confederate States for the Eastern District of Virginia. CHAS. H. WYNNE, PEINTBB, PREFACE The writer, having had access to several interesting works on the subject of artillery that are now very difficult to obtain, has con- cluded to publish these ^' Notes," hurriedly written, as they have been, in a few spare days. He does so with the hope that they may interest and instruct his fellow-comrades in arms, especially those who have lately enteced this arm of the service, and may in some remote degree aid the great cause so dear to his heart. He has had access to and used the information derived from the following works : Artillerist's Manual^ by Lieut. Gibbon, U. S. A. Ordnance and Gunnery, by Capt. J. G. Benton, U. S. M. A. Shells and Shell Guns, by Com. J. A. Dahlgreen, U. S. N. Rifles and Rifle Practice, by C. M. Wilcox, U. S. A. Notes on Sea Coast Defence, by Maj. J. G. Barnard, U. S. A. The Science of Gunnery, by William Greener, of .London. Observation^ on Fire Arms, by Col. Chesney, Royal Artillery. Military Commission to Europe, by Maj. Mordecai, U. S. A. Treatise on Fire Arms, by Lieut. Simons, Bengal Artillery. Rifle Practice, by Col. Jacob, Bombay Artillery. He has also made use bf information derived from the writings of Kobins and Hutton. 4Ji52?3 CONTENTS I. PAOB Ancient and Moderd Arms *. 9 11. Gunpowder.... » ; 18 III. The Smooth Bore and the Howitzer — the Cause of their Deviations.., 18 IV. The Rifle Cannon— "Drift" of the Ball and its Cause 28 V. Resistance of the Air 40 VI. Pnzes 46 VII. Sighting Guns — How to Make Sights 48 VIII. Classes of Projectiles — Classification ,of Fires — When each should be used .•. 54 IX. Miscellaneous Memoranda — Care of Horsed — To guard against the enemy's fire — Penetration of Shot— Iron Clad Vessels 68 X. Tables of Ranges and Elevations 62 4pc:p^^o NOTES ON ARTILLERY ANCIENT AND MODERN ARMS. • The common sling, no doubt, constituted the first kind of Artillery, which was followed by the bow and arrow, and this latter weapon was improved in succeeding ages by the bal- lista and catapulta, &c. The ballista of the ancients hurled stones from 2 to 300 pounds weight, or even, it is said, 500 pounds, about 100 yards, and the catapulta projected arrows and iron bolts twice that distance. These machines were in use more than a thousand years before the Christian era, when Uzziah had engines in Jerusalem ^* invented by cunning men, to be upon the towers and upon the bulwarks, to shoot arrows and great stones withal." (2 Chron. xxvi. 15.) Gunpowder became generally known in Europe in 1320 j and about this time it was first used in Europe to projeot founded stones from short conical guns, made in the shape of an apothecary's mortar. These were succeeded by FerriereSy made longer and cylindrical of bars of iron bound together by hoops, with a chamber for the powder. The introduction 10 NOTES ON ARTILLERY. of the cast iron, instea^ of the stone projectiles, caused the rejection of the Perrieres for the Culverijis, a gun somewhat like that used at present, of cast metal, only much longer bore, and generally ornamented in the exterior with various devices. There is one now at Dover, England, 25 feet long, which throws a projectile of 18 pounds, called " Queen Anne's Pocket Piece." « While it is generally admitted that the use of artillery be- came common in Europe in the fourteenth century, we should not fail to mention, that the Chinese claim to have been familiar with gunpowder and fire arms long before the Christian era, and it is said that the Moors used artillery against Sara- gossa in 1118, and that a Culverin of 4 pounds calibre was made bj* them in 1132. In a catalogue prepared in 1381, of ordnance at Bologna, there is mention made of a copper gun which carried a ball of 361 pounds' weight, and of three iron ones which carried square* projectiles. In the repository at Woolwich, there is a gun marked, *' Henry VI. 1426," with a movable breech ; thus showing that breech-loading cannon are of the very earliest construction. Divers calibres were early made. Charles VIII. of France restricted his artillery to six different calibres; and, when invading Italy (1494), carried in his train 1,000 hacquebuttes, or hand guns, weighing about 50 pounds each. These were fixed with a rest or stand. Shortly afterwards, a lighter gun was made, called an arque- huse. In 1521, the Spaniards gained a victory over the French by the employment of 2,000 arquebusiers and 800 musketeers, " who now appeared for the first time discharging bullets of two ounces weight." We thus see that cannon had* been in use two hundred years before the introduction of the musket. • All the various systems of calibres that were first intro- ANCIENT AND MODERN ARMS. 11 duced in Europe were finally reduced to the French or Ger- man system, or to a combination of them. The French sys- tem consisted of calibres of 32, '16, 8 and 4 pounds. The* German consisted of 48, 24, 12, 6, 3 and IJ pounds. A system of uniformity in the construction of guns was only introduced in France, in 1732, by Valiere, who caused a prescribed standard to be adopted. But, in 1765, Gribeauval effected the most important changes in artillery. He dimin- ished the charge of powder from one-half to one-third the weight of the ball, and thereby made the gun much lighter ; he disposed the horses in double file, having been previously arranged in single ; he introduced iron axle-tree^ cartridge instead of loose powder, elevating screws and tangent scales, •and compelled all the arsenals to make the work according to fixed dimensions. Afterwards, he reduced all field carriages to two, making the wheels of the limber and of the carriage the same. In 1850, the Emperor Louis Napoleon proposed and caused to be adopted in the French service only one calibre for field service a 12 pounder howitzer-gun, to be used with solid shot, to supply the place of the 8 and 12 pounder guns and of the 24 and 32 pounder howitzers. All the field batteries in the French service in the Crimean war consisted of these Napoleon guns, as they were called, each drawn by eight horses. In 1856, it was proposed to retain in service in the old United States only one calibre for field service, very simi- lar to the new Napoleonic gun. The piece was to be brass, of 12 pounder calibre, 16 calibres long, weight 1,200 pounds ; charge of powder 2i pounds, stme as in the old iron 12 pounder. The weight of this gun and carriage would be only 600 pounds more than the 6 pounder field piece with its car- riage. To give great mobility to a portion of the battery, it J2 NOTES ON ARTILLERY. was proposed to retain in the service the light 12 pounder howitzer. . We thus see how gradual the improvements in artillery have been. It was many years before field artillery was separated from siege and garrison ; and, even in 1830, a gun of 24 pounder calibre was the heaviest mounted on the sea-coast batteries of the United States, where now we find 10 inch columbiads, casting a ball of 130 pounds weight, with a charge of 16 pounds powder. GUNPOWDER. IS ♦ II. GUNPOWDER. The Chinese claim to have been familiar with gunpowder long anterior to the Christian era. We know not how much credit to give to their historic records, as they also claim to have recorded astronomical observations of phenomena that occurred thousands of years prior to the period assigned for the creation of the earth in the Mosaic cosmogony. By some it is supposed that the use of gunpowder was introduced into Europe by the Saracens. Roger Bacon, in his Treatise de Nullitate Magise, Oxford, 12 J 6, gives the component parts of gunpowder; but it only became generally known through- out Europe in 1320, through the exertions of Bartholdus Schwartz. Gunpowder is composed of nitrate of potassa, charcoal and sulphur, combined in proportions slightly varying in different countries, intimately mixed and granulated. The following table gives the proportions required by the atomic theory and those used by different nations : 14 NOTES ON ARTILLERY. TABLE OF COMPOSITION OF DIFFERENT GUNPOWDERS. • ■ Nitre. Charcoal. Sulphur. Atomic theory would require 74.64 1357 11.85 United States Military, . 76 14 10 • United States blasting and mining, 62 18 •20 English, . . . 75 .15 10 French national. 75 12.5 12.5 French sporting, 78 ,. 12 10 Prussia, 75 13.5 11.5 Russia, . 73.78 13.59 12.63 Austria, 72 • 17 16 Spain, . 76.47 10.87 12.75 Sweden, 76 15 9 Chinese, 75 14.4 9.9 The explosive power of gunpowder is due to the rapid con- version of the solid constituents into Jieated gases. Carbonic oxide, carbonic acid, sulphurous acid and nitrogen are iinme- diatelj set free, leaving a residuum of sulphuret of potassium. It is calculated that, without a change of temperature, the gases developed would occupy a space nearly one thousand times greater than powder in, the solid form. But at the in- stant of change from soli-d to a gaseous condition, we know great heat is developed thereby, causing the gases to occupy a much larger volume, and increasing vastly the explosive power of fixed gunpowder. This "explosive power" is diiferently estimated by different experimenters, depending on the heat which they assume to be generated at the time of explosion. Robins, who neglected entirely to consider the heat gene- rated, estimated the explosive force of gunpowder at 1,000 atmospheres ; Hutton estimated the force at 2,050 atmos- pheres; Dr. Gregory at 2,250 j Gay Lussac at 2,137; and GUNPOWDER. 15 Piobert estimated the force at as much as 7,500 atmospheres. The great difference due to these estimates is due to the fact, that it is impossible to estimate accurately the amount of heat generated at the instant. of explosion. * The solid matter of powder is not instantaneously/ converted into gases. It requires an interval of time, no matter how short, to produce entire combustion, and the time required for the same weight of powder depends on the size of the grain. The larger the grain, the longer is the time occupied in com- bustion. Hence, in rifles and sporting guns very fine grain powder is used ; while for guns of heavy calibre large grain powder is required. Were the powder in a 12 pounder gun instantaneously/ converted into gas, it would necessarily burst the gun. Time is required to overcome the inertia of rest of the ball. And as inertia is proportioned to the mass, the tirpe reqaired for the combustion of powder to safely project a ball from any gun is proportioned to the weight of the ball; hence, the larger the ball, the larger the grain of powder that is used. * . It is said, that fn the large Federal gun which projects a .ball of 400 pounds, the grains of the powder used are larger than chestnuts. The conversion of a portion of the charge produces suflii- cient force to impart motion to the ball, and its velocity con- tinues to increase until all of the charge has been converted into a propellant gas. By increasing the length of the bore too much, friction of the ball against the bore is Increased, and its initial velocity thereby diminished. By increasing the charge of powder, a portion of it is expelled from the ^un before it is converted into gas, and thereby the velocity of the ball diminished by adding the weight of the unconsumed powder to the weight of the ball to the projectile. 16 . NOTES ON ARTILLERY. From many careful experiments, Dr. Hutton by induction inferred the following laws : 1. The velocity varies as the square root of the charge. 2. The velocity of the projectile increases to a certain in- crease of charge ; beyond that, it diminishes. 3. The velocity of the ball increases in a somewhat less ratio than the square roots of the lengths of the bore, ^and somewhat greater than the cube roots. 4. The range increases nearly as the square root of the velocity ; hence, the range is nearly as the fifth root of the length. Hence we see, by increasing the length, a very slight in- crease of range is obtained. For field service, one-fifth of the weight of the projectile is usied for a charge for solid shot, spherical case and shell from guns ; for canister, one sixth of its weight ; and for shell ^nd case shot from howitzers, one-twelfth. The French at one time used chlorate of potash in the manufacture of gunpowder ; but it was soon abandoned, owing to its instantaneous explosion, as no piece of ordnance could rfesist its effects. In field service, the cartridges should be well packed in their chests, with cotton or tow, to prevent their rubbing or jolting against the sides of the chest, as thereby, in their transportation, some of the grains of each cbarge would be liable to be ground to dust, and its efficiency much diminished. They should not be packed so tight as to interfere with a hasty removal from the chest should ^occasion require. The friction primers should be carefully packed in a small parper or tin box with cotton, and tied so as not to come loose in traveling, and placed in the tray separate from the powder. Of course, a dozen or so should be kept in the tube pouch GUNPOWDER. 17 ready for immediate use. No broken cartridge or loose pow- der should be permitted in the chest, as it is an established fact that powder can be made to explode by the impact of a hard substance, and a few grains being between two balls brought powerfully together by a sudden jar might produce a serious explosion. The ammunition chests should be opened and the cartridges carefully aired and sunned on every dry day succeeding damp weather. 18 NOTES ON ARTILLERY. III. THE SMOOTH BORE AND THE HOWITZER— THE • CAUSE OF THEIR DEVIATIONS. Military writers assert that explosive hollow projectiles were used from 1521 to 1580, but it is doubted if the modern bomb was understood at that period. The present howitzer is an invention of the Dutch artillerists, and derives its name from the German Hauhitz. * The distinctive characteristic of the howitzer is that it has a chamber for the reception of the cart- ridge. The object of the chamber is to hold the small cartridge in position, that the whole explosive force may be exerted against the centre of the ball. Without it the small cartridge in the large bore would be displaced. It is also much shorter than other cannon of the same calibre, and being used with charges of only one-twelfth the weight of the solid ball, it is made much lighter, not requiring a great thickness of metal to resist the effects of explosion. From the gun we fire solid shot, spherical case, shell or canister ; but from the howitzer it is not usual to fire solid shot, as with the small charge of powder used, on account of limited amount of metal at the breech, but little initial velocity would be given the ball. The metal required to cast a 12 pounder gun put in the form of a howitzer, enables us to project a 24 pound shell. As shells are effective by their e^-plosion and not by their velocity, it is no^ required that they should have an initial velocity as great as that given to solid shot. In the United States the proportions between the weight of THE SMOOTH BORE AND THE HOWITZER. 19 the b*all and the gun are, in the 12 pounder, 299 to 1 ; in the 42 pounder, 201 to 1 ; in the 10 and 12 inch columbiads, 137 to 1. In brass guns the proportion is 147 to 1. Senderos places the tenacity or cohesive force of wrought iron at 4234 atmospheres, of bronze at 3872, and of cast iron at 1358 atmospheres; while Navier places the cohesive force of wrought iron at 4164| atmospheres, of bronze at 2475, and cast iron at 1307. We thus see that wrought iron is the strongest material for. guns, bronze next, and cast iron the weakest. From the diffi- culty of constructing wrought iron guns that material has not yet been successfully used. Bronze guns, composed of ten parts tin to one hundred of copper, are made much lighter than iron ones, on account of their greater tenacity, and hence that material is used for field pieces when it can be obtained. This is the only advantage that bronze guns have over iron ones, that of being lighter; while for long use and rapid 'firing, iron guns are superior to bronze, as we shall presently see. The difference between the diameter of the ball and the bore of the gun, called windage, varies from nine-hundredths to sixteen-hundredths of an inch. On account of this, when the ball rests in the bore in front of the charge, there is a space in the upper part of the bore above the ball equal to the wind- age. When the charge is fired the propellant gas escapes largely by this unoccupied space above the ball, and wedges it down against the bottom of the bore with great power, causing it to form an indentation called a had. When the gas acting behind the ball moves it forward, it does not move in the direc- tion of the axis of the piece, but, on account of the obstacle of its bed, it rises upward and strikes the upper part of the bore, producing a burr, called a lodgment ; and again is thrown down, producing another lodgment^ forming thus two or 20 NOTES ON ARTILLERY. three ricochets in the bore before it issjjes from the muzzle. A bronze gun, being softer than the cast iron projectile, would, by repeated firing, have permanent lodgments made in its bore, which would seriously interfere with its accuracy of fire, and in time destroy the utility t)f the gun. When a gun is thus injured, its usefulness is in a manner restored by lengthening the sahot, causing the ball to assume a new hed. A bronze gun "will not bear rapid firing, since when the metal becomes €nuch heated, it is soft and the gun is apt to droop at the muzzle. Cast iron guns are not injured by lodgments on account of their hardness, nor are they seriously affected by rapid firing. At the siege of Badajos the firing continued for 104 hours, and the number of rounds that each gun fired averaged 1,249. At the siege of Sebastian each gun averaged 350 rounds in 15J hours. " The guns were of iron, and none were rendered unser- viceable, though three times the number of brass guns would not have been equal to such long and rapid firing." Experiments have shown that the power of a gun to resist explosion increases with the length of time that it is allowed to remain after cast before it is used. While guns cast but a few days have burst on a few fires, those cast for thirty years have resisted the shock of more than 2,000 rounds. These deviations, which no accuracy of aim can wholly over- come, are due to two causes: (1) windage or difference between the diameter of the ball and the bore of the gun ; and, (2) the excentricity of the centre of gravity of the ball or shell. These causes do not act separately, but the deviation is gen- arally the resultant of the two. Numerous experiments were made in France, as recorded in the Encyclopoedia Britannica, to observe the deviation of the projectile from the axis of the bore, by placing a screen 30 yards in front of the muzzle. The result of the experiments demonstrated that the devi- THE SATOOTH BORE AND THE HOWITZER, 21 ation arising from the two causes, though not always, is, gen- erally, an elevation. The average deviation amounted to 3 J min- utes in guns, and to lOJ minutes in howitzers — one-fourth of the shot from the guns having an elevation of more than 8J minutes, and a depression below the axis of IJ minutes. In howitzers one-fourth had an elevation of more than 15J min- utes, and one-fourth 5} minutes above the axis ; the remaining shots passing within these limits. In a horizontal direction half of the shots deviated from the axis more than 4J minutes to the right or left. The author of the article "Artillery," in the new American Encyclopoedia, says the effective range of field guns is not over 1,500 yards, at which distance one shot out of six or eight might be expected to hit the mark. The decisive ranges in "which alone cannon can contribute to the issue of a battle are for round shot and shell, between COO and 1,100 yards, and at these ranges the probability of striking the object is not very great. It is reckoned, that at 700 yards, about 50 per cent. ; at 900 yards, about 35 per (ffent ; and at 1,100 yards, about 25 per cent., out of the" shots fired from a 6 pounder will hit a target representing the front of a battalion in column of attack, (31 yards long by 2 yards high). In 1850 experiments in France with 8 and 12 pounders gave the following results against a target, 30 metres by 3 metres, representing a troop of cavalry : Distance in metres, . ^ . 500 600 700 800 900 Per cent, of 12 pounder hits, 64 54 43 37 32 Per cent, of 8 pounder hits. 67 44 40 28 28 22 NOTES ON ARTILLERY. This table shows the superiority of a 12 pounder over a 6 pounder for all distances over 550 yards. • From th^se experiments we would infer, that even if the centre of gravity of the projectile coincided perfectly with the centre of magnitude, still there would be considerable.deviation, depending upon the angle which the projectile would make with the axis of the piece. But the main cause of the deviation is due to the excentricity of fhe projectile, which is measured by the distance between the centre of magnitude and the centre of gravity. Owing to the nature of the .material of which projectiles are made, it is almost impossible to avoid excen- tricity ; consequently, if we suppose the resultant of the propellant gas to act on the centre of form, and not on the centre of gravity, by a simple principle of mechanics it follows, that the ball will have both rotary and pro- gressive motion, and the rotation will be around the centre of gravity. This rotation may be further modified by friction against the interior of the bore. Hence we may safely assert, that every round projectife fired from a smooth bore gun rotates around some axis. If this axh of rotation is not coincident with the line of fire, the projectile will be deviated from its straight course by the inequality of the resistance of the air on the sides of the revolving projectile. Suppose the axis of rotation of the ball is perpendicular to the line of fire, and the ball revolves from right to left, it is obvious that the resistance of the air on the right hemisphere of the ball is due to the velocity of progression added to that of rotation, while the resistance experienced by the left half is due to the velocity of progression diminished by that of rotation. Hence, under* the circumstances, the right half would have a greater resistance acting upon it than the left. The resultant of this excess of resistance would tend "constantly to push the ball to the left, THE SMOOTH BORE AND THE HOV/ITZER. 23 and thereby cause deviation from the line of sight in that direction. In 1737 Mr. Robins, in his numerous experiments, observed these irregular deviations, and' assigned these deflections "to the oblique action of the resisting medium on the surface of the ball, arising from its rotary movement." In 1771 Robins' conclusions received a remarkable verifica- cation. A screen was placed 32 feet from the muzzle, and a ball which pierced the screen five-sixths of an inch to the right of the prolongation of the axis, at a range of 3,765 yards, deviated 230 yards to the left, and another which pierced the screen one inch to the left, at a range of 4,072 yards, deviated 230 yards to the right. These anomalies can be explained only by the rotary movement. As late as 1838 the subject of the excentricity of the deviations caused thereby was not generally understood, as is admitted by General Paixhans. This igno- rance of an importan-t subject, which had been explained one hundred years before, is by no means complimentary to artil- lerists. We take the liberty of quoting upon this interesting subject from Dahlgreen's Shells and Shell Guns : " The doctrine," he says, *' commonly received and con- firmed by experiment, in relation to excentricity and its conse- quences upon the trajector}^ of cannon balls, may be briefly summed thus : When the centre of gravity does not coincide with the centre of the sphere, a revolving motion is created around the centre of gravity, the direction of which depends on the position that the centre of gravity has to the centre of the sphere. This rotation during the flight of the projectile occasions a greater resistance on one side of the hemisphere, which is in front, tli.an on the^other; because on the former the progressive and rotatory motions concur, and on the other , 24 NOTES ON ARTILLERY. they are in opposition. Hence, the projectile is made to in- cline from its direct course by the greater pressure which it sustains on one side ; and the aberration thus produced will be in the prolongation of the plane passing through the axis of the bore and centre of gravity, and will occur on the same side of the trajectory as the centre of gravity occupies with respect to the axis of the bore. " So that if the centre of gravity be in the vertical plane, the deflection from the normal trajectory will be vertical and upwards, or downwards, accordingly as the centre of gravity is in the upper or lower hemisphere. If above, the range will be increased ; if below, decreased ; by the very conditions of the case, and without lateral deviation. " If the centre of gravity lie in the horizontal plane, the deflection will be entirely lateral and right or left as the centre of gravity may lie. If the centre of gravity occupy some position between the vertical and horizontal planes, as it commonly does, then the aberration will be partly vertical and partly lateral. It doe« not appear that the location of the centre of gravity in the anterior or posterior hemisphere, materially effects its operation ; except that there is a slight increase of range where the centre of gravity is in the poste- rior hemisphere and in the axis of the bore." Dahlgreen found, that by placing this centre of gravity of an excentric ball 90° up, the range was increased nearly 200 yards. We will conclude the notes on this subject by mentioning some facts in regard to the ordnance of the siege of Sevasto- pol, taken from the report of Major Mordecai, of the Ord- nance Department. At the siege of Savastopd no cannon of extraordinary . calibre or range, no breech-loading guns, no rifled cannon, THE SMOOTH BORE AND THE HOWITZER. 25 (except the Lancaster gun,) were put to the test of actual service. Before the impromptu fortifications of Sevastopol the allies placed in battery, at various times during the siege, more than 2,000 pieces of heavy ordnance, besides the hun- dreds of field pieces with which the troops were armed. The first siege train with which the French army presented itself before the place consisted of sixty pieces of the calibres usually employed in such operations, 16 and 24 pounder guns, 8 inch howitzers, and 8 and 10 inch mortars. These being soon found insufficient, were followed by other trains, amount- ing to 250 pieces. Many guns of heavier calibre were drawn from the fleet ; but the armament which, at last, appears to have been most efficient in rendering the works untenable was a train of mortars, of which the French alone had 120 thirteen inch, the same number of ten inch, and about 100 eight inch. 'Add to these the English siege train of more than 900 pieces, consisting chiefly of 68 pounder and 32 pounder guns ; 13 inch, 10 inch and 8 inch mortars ; a considerable quantity of which were in battery at the close of the siege, and some idea may be formed of the storm of shot and shell which was poured upon the works during the bombardment of three days preceding the last assault. " The appearance of the ground within the Malakoff" and Redan bastions, after the retreat of the Russians, showed the impossibility of serving the guns of the palace during the bombardment. It was scarcely possible to plant a foot on a spot on the terreplain of those works which tvas not marked hy a cannon hall, or hy the explosion of a shell, and the de- fenders could only remain there under cover of their bomb- proof shelters, which, although mostly constructed rudely of timber fascines and earth, seemed to have generally resisted the fire of the besiegers,'' • 26 NOTES ON ARTILLERY. How very culpable lia\^e been those who have had charge of the construction of our fortifications 1 At Sevastopol, while under a fire and during the operation of the siege, the Russian engineer had "bomb-proof shelters of timber fascines •and earth" constructed in the fortifications, which afforded a safe protection against a storm of shot, and shell from 2,000 can- non during three days. While our engineers with months before them, and no enemy in sight, have been content to build open pens, which have surrendered after a brief struggle of a few hours. Let our generals in command see to it that our engineers have work done with no enemy to molest, at least as well as Totleben had constructed under the galling fire of the allies. " The number of pieces of ordnance burst at Sevastopol was small in proportion to the whole number used. But it was stated, that about two-thirds of the ordnance used in the siege was considered unserviceable at its termination. Many of the guns had been rebouched ; some of them two or three times ; some bouchings of wrought iron were tried, but did not last long. The French siege trains were supplied with 1,500 to 2,000 rounds a piece*; their batteries fired during the siege about 1,250,000 rounds of all kinds, and at the close there remained fi«om 800 to 900 rounds of ammunition for each piece. The field batteries were supplied with 1,000 rounds for each piece." Of all the guns used by the British only twelve burst. Three of these were Lancaster guns. In the report it .is stated, that the 32 pounder guns fired on an average 1,500 rounds each. Captain Kennedy, of the Royal Navy, says in his report : "The 68 pounders landed from the * Terrible' were con- stantly in use, and I slfould say the least number of rounds THE SMOOTH BORE AND THE HOWITZER. 27 fired from any one of them was 3,000 ; some of them went up to 4,000. They were fired with the 16 pounder charge, and frequently very rapidly." The allies found in Sevastopol about 4,000 pieces of ord- nance of all kinds ; but the number of unserviceable pieces was tivice the number in battery ! Showing that the guns had been several times renewed. The Russian gunners were pro- tected from sharp-shooters with the rifle by a mantlet, made of rope, to cover the embrasures. A field-cannon ball will disable seven or eight m^ at a dis- tance of 900 yards. It is said, that at the battle of Zorn- dorfi*, a single ball disabled forty-two men. 28 NOTES ON ARTILLERY. IV. THE RIFLE CANNON— " DRIFT " OF THE BALL, AND ITS CAUSE. It is stated that rifles have been in use since 1600. The principle of the rifle was clearly stated by Robins in 1737, viz : 'that as the deviation of the ball was caused by the un- equal pressure of the air, produced by its revolution, this cause of deviation would be wholly destroyed by causing the ball to revolve around an axis coincident with the line of flight. The motion of rotation being at right angles to that of progression in no measure influences the resistance of the air. The ball is caused to revolve on this axis by "rifling" the bore, or cutting in it the threads of a female screw. The spherical ball was used with the rifle for many years, and this with the diSiculty of loading, (the ball necessarily having to fit tight to take the threads,) prevented its adoption by troops in the field. In 1829, Delvigne proposed to remove the difficulty of load- ing, by flattening a smaller ball on the edge of the chamber with a blow from the ramrod. Thouvenin afterwards proposed to use a small stem projecting from the breech plug into the bore, around which the ball was to be flattened by the ram- mer. Delvigne afterwards made the base of the ball flat; hence the conical or elongated ball. • THE RIFLE CANNON. 29 Minie afterwards made the stem of Thouvenin in the form of a cone and fixed it in the ball, instead of the breech of the gun. This culot^ by the propellant gas, (having less inertia) was thrown forward into the ball and expanded it to fill the bore. Afterwards it was discovered that the gas acting in the hollow cavity of the ball expanded it without the culot of iron. Hence we have the present " cylindro-conoidal ball." W. Greener, of London, claims priority in the discovery of what is now called the "Minie ball." About thirty years ago Cavalli S. WahrendofF constructed breech loading rifle cannon, which eventually failed. Later, Lancaster introduced his rifle cannon of elliptical bore. It was like a smooth bore with its section an ellipse instead .of a circle; having the major axis of the ellipse at the muzzle at right angles to the major axis at the breech. Great results were anticipated of the Lancaster guns. They were tried at the siege of Sevastopol, and utterly failed to realize the expectations previously entertained. Several of them burst on account of the wedging of the shot in the bore, when the elliptical shot were abandoned and they were fired with spherical. The principle of the expansion of the Minie ball was, imme- diately after its application to small arms, applied to rifle can- non. For a while there seemed a difficulty in attaching the hollow cup of soft metal at the base to the metal of the ball. This difficulty is now overcome, and the elongated ball is fired from rifle cannon of the largest bore. It has been found by fastening an inverted copper saucer at the hasp of the ball the windage is destroyed and the* rotary motion given. In the examination of the smooth bore, we found there were two principal causes of deviation in the ball, windage and the excentricity of the ball causing a revolution around some other 5U NOTES ON ARTILLERY. axis than that coincident with the normal trajectory. Both of these causes of deviation are entirely eliminated in the rifle cannon. ' * By the action of the gas on the soft metal at the base of the ball, it is expanded to fill up entirely the bore, and thereby cuts off all escape of a gaseous fluid. Hence the ball is pro- jected with very great velocity, as all the propellant gas acts on it, and, moreover, its elasticity is much increased by thus confining it and allowing none to escape. The soft metal is thus pressed into the grooves, and as the ball moves forward it acquires a rotatory motion around an axis coincident with the axis of the bore. Hence the deviations to which the smooth bore is liable are entirely obviated in the rifle cannon, inas- much as the expansion of the cup cuts off the escape of gas, and thereby prevents lodgments in the bore. -The ball is made cylindro-conoidal, having thereby nearly twice the weight of a sphere of same calibre, and meets with much less resistance Crom the air. Considerably less powder is required to give a larger ball much greater range, with far greater accuracy, than can be done with a smooth bore. ' -* » While it is true that a ball from a rifle cannon is not liable to the enormous and irregular deviations of a smooth bore, yet it is found bj- practice to be subject to another deviation peculiar to itself. It is found that the ball will not continue to move in a vertical plane, but will depart from it towards the right, if the ball is revolving from left to right, or in the direction of the hands of a watch held before you. If the revolution of the ball is in the contrary direction, the departure will be towards the left. This deviation of the rifle ball is technically called the ''drift'' of the ball, and it is said the ball "drifts" in the direction in which it revolves. The "drift" only takes place with the elongated ball, and the amount of deviation seems to THE RIFLE CANNON. 31 depend on the range. The French rifle guns used in the Italian war were provided with a graduated lateral slide, by means of which the eflfect of this deviation was corrected. If the drift was towards the right, it became necessary to point the rifle towards the left of the object, which was done by sighting at the object over one of the graduations to the left of the vertical tangent right. Sufficient number of experiments have not yet been made with our guns to determine the amount of deviation corres- ponding to each range, and without these experiments we do not know how to graduate this lateral sight. The Armstrong gun is a breech lo-ading rifle cannon of small calibre, with a bore made of twisted steel. It is said to have remarkable range and accuracy ; that it may confidently be relied on placing shot after shot in a target 6 feet square at a distance of 3,000 yards. The "drift" of the gun is always towards the right, in the direction of its revolution. Colonel Jacob, in his "Rifle Practice, London, 1858," denies that the deviation of the ball is always towards the right, and that it is generally so, he attributes to the fact that the rifle is fired from the right shoulder. He argues that the breech of the rifle resting against the right shoulder, by the force of recoil, does not tend to move backwards in the prolongation of its axis, but tends to revolve around the centre of gravity of the mass of the hodj and rifle, which throws the muzzle of the rifle slightly towards the right before ut. mond Enquirer, and<-^i>w.A/t! Examiner. 12.— De VERE. A story of HiLLiARD, of Alabama. Address orders to itia. A new and revised edition, with plates, I^E WAR; composed from authentic mate- ■iry movemouts, incidents, romances, and ex- 's Administration to the period of publication, .'f political events since the foundation of the By B. M. DeWitt, former Editor of the Rich- - A. Pollard, Associate Editor of the Richmond ana i' at:;^icians. 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