Ktljaca. SJein ^ork BERNARD ALBERT SINN COLLECTION NAVAL HISTORY AND BIOGRAPHY THE GIFT OF BERNARD A. SINN,'97 1919 Cornell University Library VF145 .W25 1861 instruction in naval ordnance 3 1924 030 896 868 olin Cornell University Library The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924030896868 ELEMENTARY INSTKUCTIOi\ IN" NAVAL ORDNANCE AND GUN]^ERY. BY JAMES H. WARD, OOMMANDEE, L'. S. N., AUTHOR OP "naval TACTICS," AND " STEAM FOR THE MILLION.' NEW EDITION, KEVISED AND ENLARGED. NEW YORK : D. VAN NOSTRAND, 192 BROADWAY. LONDON: TRUBNER & COMPANY. :si.£iCCe.LXI. \' ]Cntered, according to Act vf Congress, in the year 1S61, liy JAMES H. WARD, in the Clerk's Otiice of the District Court of the United States for tho SoutheLJi District of New Yoi-k. JOHN F. TROW, PRINTER, STEREOTYPER, AND ELECTROTVPER, ■Ifi, iR &. 50 Greeoe Street, New York, TABLE OF CONTENTS. P A E T I. SECTION I. PAGE Definitions. — Historical Review of Ancient Artillery, and Ancient Modes of Engagement in Maritime Actions. — Engines of War used in the Middle Ages. — Discovery of Gunpowder, and Invention of Cannon. — Steps in the History of Cannon. — Armaments used at Lepanto ; in the Spanish Armada ; in the Early British Navy ; in the British and Combined Fleets at Trafalgar. — Armaments Going out of and Coming into Use, and the Popular Reasoning, ... 1 SECTION II. Matter and Motion. ^Inertia of Matter. — Weight. — Specific Gravity, or Density. — Rehition of Can^'C and Effect. — Action and Reaction. — Mo- mentum, or Quantity of Motion. — Parabolic Theory of Projectiles. — Atmospheric Resistance. — Effects of Atmospheric Resistance upon Balls of Different Diameters, Densities, and Velocities, . 14 SECTION III. Recapitulation. — Velocity of Balls, Initial and Remaining. — Experiments with the Ballistic Pendulum. — The Effect of Weight in Guns on their Recoil, and on the Ranges of Shot. — The Celebrated Sutton Heath Practice. — Pvelative Accuracy of Different Calibered Guns at Distant Ranges. — Relative Penetration of Shot of Different Diameters. — The Nature of Battery Determined by Reasoning from the Foregoing Con- siderations, and Introduced, as most Proper for Different Classes of Vessels, 2.5 SECTION IV. Construction, Proof, Inspection, and Preservation of Guns. — Construction and Equipment of Gun Carriages, ....... -tO IV CONTENl-H. PAGE SECTION V. Gunpowder, its Fabrication, and the Tbeory of its Explosion. — Proportion- ing Cliarges of Powder for Guns of Different Weights, as Compared with their Shot. — Charge for Double-Shotted Long Guns, and for the 8-inch Paixhan. — Flannel Cylinders. — Filling Powder. — Reduced Charges, . 67 SECTION VI. roasting Shot. — Windage. — Eccentricity of Shot. — Effects of Eoughuess of Surface and Eccentricity on the Accuracy of a Shot's Flight. — Inspec- tion and Preservation of Shot. — Wads. ... . . 83 SECTION VII. Implements used in Serving Guns. — Loading Guns, Sponging and Attending Vent. — Loading with Cartridge and Ramming Home. — The Use of AVads in Shotted Guns. — Double-Shotting Guns. — Loading with Round and Grape. — Penetration of Shot. — Penetration from Carronades.- — Firing with Damaged Powder. — Ranges of Guns of Different Calibres and Weights, at Point Blane, and at Different Angles of Elevation. — Ricochet Firing. — Shells, . . 9Y SECTION VIII. Pointing and Sighting Guns. — Target Practice, . . . . .111 P A E T II. SECTION L Metal for Guns. — Iron. — Smelting. — Rationale of the Process of Smelting. — Wrought-iron and Steel. — Puddled Steel, . .128 SECTION II. Moulding Guns, etc. — <"'aEt)ng and Working the Iron, . . , 137 SECTION IIL Rifles and Rifled Cannon, . .... 143 SECTION IV. Mounting and Equipping Guns. — Training Guns. — Elevations. — Distribu- tion of Displacement. — Securing Guns. — Graduating Decks. — Ports 15.'5 SECTION V. Quartering and Stationing Men. — Stowage of Powder. — Drowning Jlaf^a- zines. — Shell Rooms, . . . . ^ ^ j^-j SECTION VL Iron and Steel-clad Ships, ...... 189 SECTION VIL Conclusion, •••••-...... lifjo PEEFACE. This book is not the result of much reading in French works, for that is what the Author has done but little, believing it, when excessive, to damage by promoting servility of thought, more than it benefits in other respects ; nor a result of much special experiment- ing, for want of opportunity, means, or leisure. It is rather the product of, 1st, a good primary training at the Vermont Military Academy, where lectures on Military subjects, especially Gunnery, were copious and frequent, — which, for the Naval career, was an inestimable advantasre, because more familiar knowledge is talked into youths than they can acquire in any other way. Study and recita- tions alone, without oral instruction, arc insufficient. The elemen- tary knowledge and familiarity thus early acquired, opened a way to the 2d source from whence the book is derived, viz., conversations with the most eminent Military and Naval officers; there is no use enumerating them ; living books they are, and read with great advan- tage by those who can. The 3d and most prolific source, is profes- sional experience of the most varied and laborious character, in the ordinary course of almost constant service, nearly ten years of "which have been passed as 1st Lieutenant in every class of vessel, or as Commander, at sea ; positions which force observation, compel con- stant quick thought and action, and induce a large degree of the administrative intuition necessary for military or naval command. The service affords many good writers. Few of them, hov,-- ever — and more's the pity — give that talent to the benefit of the profession proper. They seem generally to prefer some other spe- cialty, as rendering a better return in eclat, or perhaps in home comforts. This again begets naturally a distaste for the sea, — at least for its drudgery, which, however irksome, is not unprofitable schooling. Hence it has got at last to be considered, that writing, and a proclivity for the sea and the naval profession proper, are VI PREFACE. incompatible, — don't run together ; and that vice versa, he who writes must, as a consequent necessity, be '' no sailor " — a phrase which, as used, implies more than it expresses. Now although this may be the rule, there are exceptions, in proof of which the Author could adduce some practical examples, amongst others (even at the risk of bad taste) himself, his service, his books, and his ships, one of which was pointed to, by a most accomplished Captain belonging to the Spit- Head Fleet assembled for the Queen's review after the Crimean war, as a model of order^ cleanliness, tone, discipline, high training and efficiency, which even British officers might study with profit. Nor need he be backward to cite his present Command, which is of a kind having its own peculiar difficulties, calling for such sufficient sway over men in large bodies as restrains them under the temptations special to a Receiving Ship : — a talent to be culti- vated, a science to be studied ; for on it, anywhere, harmonious discipline and true military strength largely depend. The Author calls upon the young men of the navy to resist, and upon public sentiment no longer to encourage the too com- mon if not general divorce of intellectual cleverness from the prac- tical accomplishments of the trained, prompt, bold and confident seaman ; and to believe that no one can ever become such, and strengthen himself and his character to the requisite standard, who eschews the labor and drudgery of the profession, seeks only dainty service, and monopolizes, through political or other unworthy, de- moralizing, almost dishonorable influences, what is significantly termed the "fat," leaving the '■lean" to those more truly high- minded but less pretentious officers who accept all orders, shirk no duty, not even the onerous responsibilities of a 1st Lieutenancy, and best preserve true self-respect by rather suffering than prac- tising that injustice which avoids a fair share of the common bur- then, casting it upon others, yet never misses a pay-day, nor fails to claim promotion, which is the legitimate reward only of entire and generous devotion to the country's best naval interests, irrespective of self There is hope in the present, that all this is undergoing radical and thorough cure ; and further, that Government will adopt the rule which has made Commanders and Captains in the British Navy what they are — tried men, who were ineligible to position except after success as 1st Lieutenant, or professional distinction of some sort. Keceitixg Ship Xoeth Carolixa, ) N"ev Tohk, MaT, 1861. ) MYAL ORDMNCE AID GUNNERY. PART L SECTION I. DEFINITIONS. — HISTOEICAL EEVIEW OF ANCIENT AETILLEET, AND ANCIENT MODES OE ENGAGEMENT IN MAEITIME ACTIONS. — ENGINES OF WAH USED IN THE MIDDLE AGES. — DISCOVERY OF GUNPOWDEE, AND INVEN- TION OF CANNON. STEPS IN THE HISTORY OF CANNON. ARMAMENTS TJSED AT LEPANTO ; IN THE SPANISH ARMADA ; IN THE EARLY BRITISH navy; IN THE BRITISH AND COMBINED FLEETS AT TRAFALGAR. — ARMAMENTS GOING OUT OF AND COMING INTO USE, AND THE l^OPULAR REASONING. Naval ordnance embraces the battery, or that which is intended for the battery, of a ship. Ordnance equipment and stores, are whatever is used to mount, handle, or serve such battery. Field-pieces, boat-guns, and musketry, are not strictly classed as ordnance, though they form an im- portant part of the armament. Naval gunnery means the use of the battery afloat in battle ; also the practice with it, and drill of the personnel at it, as a preparation for battle. In preparing a ship, and disciplining the crew for service, fitness of battery, skill in its use, and preser- vation of the military stores, are regarded as objects of 2 UISTORICAL EE\IEW OF AlfCIE^'T WARFARE. paramount importauee ; for although in other respects well provided, clean, and neatly rigged, and with an active crew, if the battery be imperfect in its construc- tion, condition, or appointments, or if, through care- lessness or false estimate of its importance the instruc- tion and extivi-se are either of them neglected, so that her gunnery is ineffective, the ship ^YSi imperfectly fulfil the chief pm-poses of her employment, be at best but an expensive jDageant, and prove really as harm- less as a gi'eat scarecrow. In opening the instruction proposed, it may not be uninteresting, or ^^ithout its use in exciting a spirit of inquiry, to notice briefly the ancient modes of sea- fighting, give some account of the artillery employed by the Greeks and Komans, and during the middle ages until the discovery of gunpowder, and trace the invention and improvements in cannon, from their ear- liest use, thi'ough intervening maritime wars, to the present time. The Greeks, and subsequently the Romans, and other ancients, fought in galleys propelled by oars, which were arranged in banks, one, two, and some- times three deep. Their contests were principally de- cided by boarding, and depended much on j)ersonal prowess as well as numbers. The galleys were con- structed with heavy iron beaks, to destroy an oppo- nent by piercing or crushing her sides. It was cus- tomary, however, to use a species of artillery. The Greeks threw, by means of a machine, a composition known as Greek fire, which is represented to have been unextinguishable, and vdth which they destroyed an enemy whilst at a distance. The Romans used the ratcqndta, for thromng darts and javelins. This cata- pulta was a machine acting upon the elastic principle of the bow : tested hides being drawn to their utmost INVENTION OF GUNPOWDER. 3 tension, and then sprung, communicating liigli veloci- ties. Sometimes suffocating mixtures, in earthen jars, were thrown upon an enemy's decks to stifle and blind the crew ; and venomous reptiles were thrown in the same way to produce terror and dismay.* The catwpulta was the light artillery of the an- cients ; and as such, fitted for use on theix light ves- sels. Their heavy artillery was the halista^ too heav)- for use afloat. In the middle ages, especially during the crusades, various other means of annoying a distant enemy from vessels were devised. The English galleys used wind- mills, which, turning rapidly, threw, hy centrifugal force, heavy stones, combustible balls, and other mis- siles. There are enumerated in the books twelve differ- ent machines for throwing missiles, which had come into use in the eleventh and twelfth centuries; but their forms, constraction, and manner of use, are en- tirely lost to history. In 1320,' gunpowder was invented by Friar Schwartz, a Grerman. There is reason to believe that an English monk, Roger Bacon, was acquainted with its properties in the preceding century. But the Ger- man fi-iar (the monastic institution-s possessing in those days nearly all the science extant), engaged with a composition of saltpetre and charcoal, accident- ally fired it, which threw a stone to a great distance. This circumstance suggested the use of the composition in war, as an agent for projecting heavy bodies from cannon. The earliest uses of this new description of artil- * "Will not some one describe popularly the great naval battles fought anciently under oars, as significant guides in devising a system for fleets to be fought under a kindred means of propulsion — steam ? 1 4 FIRST COXSTEITCTIOIir OF GUNS. lery ai-e noticed as having occurred at Cressy, by tlie Black Prince, in 1346, on land; and at sea, in 1350, in an action between tlie jMoorish King of Seville and the King of Tunis; and again by the Venetians in 1380. On this last occasion, it is remarkable that na- tions generally exclaimed against its use, as imfair in war. It Avas not then foreseen, as has since proved the case, that gunpowder would render war, especially in naval battles, less sanguinary. Anciently, the ob- ject in sea engagements was to board, and in hand-to- hand combats destroy life. But the chief effort now in fighting ships with guns, is to cripple or destroy the ship ; which accomplished, men are compelled by necessity to surrender. The first guns in use were constructed "with bars of Avi'ought-iron, hoojDed together by iron rings, and threw leaden balls. The nest step in gun-making produced brass ordnance of enormous calibre, throw- ing stone balls of a weight equal, in some instances, to 1,200 pounds. Louis XI. had a celebrated gun of this calil^re ; and Mahomet II. breached the walls of Constantinople, at the siege of that city in 1449, with a gun and balls of this description. Next, both WTOught-iron and brass-cast guns came into use, of a much reduced size, throwing cast-ii"on balls. These wrought-iron guns were made by weldino- bars together, which were formed to a perfectly cylin- drical shell, and this was hooped A^dth several strong iron rings. There have been recovered, not long since, from the " Mary Rose," an English vessel of war, sunk by a French fleet on the coast of England in 1545, two guns ; one of wrought iron, constructed as just de- scribed, and the other of brass, cast. This brass gun contained an iron ball. DISCOVEEY OF THE POLARITY OF TILE JSTEEDLE. 5 Until SO late, however, as tlie year 1558, when cast-iron guns were introduced, more than two hun- dred years after the discovery of gunpowder, cannon do not appear to have been so securely made, as not to produce, by their liability to burst, as much appre- hension amongst those who served them as among the enemy ; and until that time, had not entirely super- seded the ancient artillery. Some time late in the thirteenth, or early in the fourteenth century, the polarity of the needle was dis- covered ; but precisely when, by whom, in what coim- try, or under what circumstances, is not known. The Portuguese had, by aid of it, ventured largely on the ocean ; but its first great effects were developed in the voyage of Columbus, which resulted in the discovery of the western world, in 1492. The Portuguese had, six years earlier, coasted the whole western shore of Africa, and doubled the Cape of Good Hope ; and six years later, 1498, the same people discovered the pas- sage to India. The ocean, which had been a barrier between nations, now, through these discoveries, and by aid of the compass, became the most convenient highway of communication. The Venetians in the Mediterranean, the Portuguese in the east, and Span- iards in the west, held possession, and attempted each a monopoly of the commerce of those regions. Na- tions contended for and against this monopoly. Mari- time wars, in consequence, assumed an imjDortance they had never before held. Commerce afforded the means of prosecuting these wars, and gujijjoivder ren- dered them formidable and destructive. The first great naval combat growing out of this new state of things, was fought at Lepanto between the Turks and Venetians in 1577. The vessels on both sides were mostly galleys, armed with light 6 THE SPANISH ABMADA. cannon. But tlie Venetians liad six ships, showing througli port-holes thi'ee long heavy guns on each side. These ships withstood the whole Turkish force, and contributed mainly to the result of that bloody day. This is probably the first notable instance on record of the decisive effect of smaller numbers of heavy ord- nance over larger numbers of smaller calibre. In the year 1588, Philip II. of Sj)ain astonished the world with the celebrated "Armada," which threat- ened the coast of England, but was defeated, and finally wrecked or otherwise destroyed in the British seas. That fleet consisted of 132 vessels, with an ag- gregate tonnage of 63,120; carried 3,1G5 guns, and 30,000 people, including mariners and soldiers. The largest of these vessels measured 1,550 tons, carried 50 guns and 422 persons. Another of them, of 1,200 tons, carried 50 guns and 360 persons ; which last was about the prevailing proportion of tonnage, guns, and men, through the fleet. The English force opposed, consisted of 175 ships, of 29,740 tons, and 14,500 men. The size of the Eng- lish ships, and the nature of the armament of both fleets, may be inferred from what follows : The " Grace de Dieu," a famous British ship, built by Henry VIII. in 1520, measured 1,000 tons, carried a battery of 103 ii'on pieces and 19 brass pieces, and a personnel of 349 soldiers, 300 mariners, and 50 gun- ners; total, 700. Of her armament, it is remarked, "that though appearing to mount 122 guns, she had in reality only 34 worthy to be called cannon, the rest being made up of falconettes, serpentines, and rabi- nettes, carrying from 1 to 3-pound balls." This ship must have been in the fleet opposed to the Armada, and may be taken as a specimen of British batteries. ANCIENT ARMAMENT OP VESSELS. 7 The " Royal Prince," another famous vessel, Luilt in 1610, twenty years after the Armada was destroyed, was of 1,500 tons burthen, about the size of the largest Spanish ships, and carried 55 guns; which is what Spanish ships of her size carried. It may, therefore, be inferred that her battery, in its nature and weight, corresponded with that of the Spanish ships. Of the 55 pieces carried by the "Prince," 2 were "cannon petronel," or 24-pounders; 6 were " demi-can- non," medium 32-pounders ; 12 were " culverins," or 18-pounders, (which were nine feet long, with 177 pounds metal to the pound of shot ;) 18 were " demi- culverins," or 9-pounders; 13 were "sakers," or 5- pounders, 6 feet long, with upwards of 200 pounds metal to 1 of shot ; and 4 were " port-pieces," probably swivels. These guns were disposed : on the lower gun- deck two 24-pounders, six medium 32-pounders, and twelve 18-pounders ; on the upper gun-deck the bat- tery was entirely of 9-pounders ; and the quarter-deck and forecastle were armed with 5-pounders, and the brood of pop-guns that in those days swelled the nominal armament of ships. In 1637, Charles I. built the " Sovereign of the Seas," more famous than any ship which had preceded, and unequalled by any afloat in her time. She mount- ed, on three gun-decks, 86 guns. On the lower deck were 30 long 24-pdrs. and medium 32-pdrs. ; on her middle deck thirty 12-pdrs. and 9-pdrs. ; on the upper deck " other lighter ordnance ;" and on her quarter- deck, forecastle, and elsewhere, " numbers of murdering peecesy This shows an increase of the size of ships and number of guns since the preceding reign ; but it may be remarked that the increase is principally in " lighter ordnance," and " other murdering peeces ; " so that, according to our modern estimation, which will 8 FIKST USE OF THE MOETAK ABTD KETCH. be shown, little addition was made to real and sub- stantial efficiency. It may here be remarked, in tbe cliain of improve- ment in naval ordnance, that the mortar was first used afloat in 1679, at the French attack on Algiers. It was then discharged from a bomb-ketch, precisely as at the present time. The ketch-rig was invented then, and is continued without change. In the severe and obstinately protracted contests between Blake and Van Tromp in Cromwell's time, it does not appear that the ships or batteries differed in any material degree from those contemporaneous in construction with the "Sovereign of the Seas." In- deed, with a single exception, that ship remained at the time of the British revolution, a whole reign after Cromwell's death, the most formidable ship, both in size and battery, in the British navy. And this, if the Dutch ships were similarly armed, explains why those ships fought a battle that was protracted through three days ; for, as will hereafter be seen, there were few guns, in either fleet, capable of penetrating a heavy ship's side, and sinking her, even at close quarters. Armed as ships now are, and with tolerable gunnery, one or the other, or both parties, must be destroyed in a few hours at most. No marked alteration in the batteries of ships ap- pears to have occurred, down to the destruction of the French and Spanish maritime power, at Trafalgar in 1806. Carronades, of small weight and great calibre, had taken the place, in many cases, of the 9 and 12- pounder long guns ; and in consequence, a nearer ap- proach to uniformity of calibre had obtained in the batteries of ships. How far this is true, will appear by stating the batteries of the " Santissima Trinidada," the hea^'iest COMPAEISON OF FOREIGN FLEETS. 9 sMp of tie combined fleet ; and of the " Victory," and otters of the British fleet. The " Santissima Trinidada " was built in Havana in 1769. She then mounted 126 guns ; viz., on the lower gun-deck, 30 long 36-pdrs. ; on the second deck, 32 long 18-pcljs. ; on the third deck, 32 long 12-pdrs. ; and on the spar-deck, thirty-two 8-pdrs. At Trafal- gar she is said, in the British accounts, to have had 140 guns, which number must have included swivels and cohorns, mounted for the occasion. The Spanish seventy-fours, in that action, had 58 long 24-pdrs. on the gun-decks ; on the spar-deck 10 iron 36-pdr. carronades, and 4 long 8-pdrs. ; and on the poop, 6 iron 24-pdr. carronades ; total, 78 guns, and a formidable battery. The French and Spanish ships had cohorns mounted in the tops; and one or two fleld-pieces, with carriage and apparatus complete, were movable on the spar-deck. " Victory," the English flag-ship on board which Lord Nelson fell, mounted on her three gun-decks 90 long 32, 24, and 12-pdi's., on the quarter-deck and fore- castle 10 long 12-pdrs., and two 68-pdr. carronades. The British second-rates, in that action, had, for new and strong ships, 24-pdrs. on the lower decks, and for old and weaker ships, 18-pclrs. The British ship " Tamerlane," the best armed for her rate in the fleet, had 56 long 32-pdrs., and 30 long 18-pdrs. on the gun- decks, and on the spar-deck twelve 32-pdr. can-onades and 4 long 18 s. At a single broadside, the weight of metal thrown by The " Santissima" was 1,190 pounds.* " "Victory" " 1,180 " * The " Wabash " and her class throw nearly 1,700 pounds at a broad- side. 10 HISTORY OF NAVAi OEDNAJSTOE. The United States sMp Delaware throws a weight of 1,814 pounds. It will be seen, in the progress of the course, that nearly every shot from this ship, had she been in that action, would have penetrated the sides of every ship there; whereas, not much more than half the shot thrown by the ships actually there, could penetrate, even at the most moderate distances. In thus briefly tracing the history of Ordnance, it appears that early fabricators, adopting an idea of the ancients in favor of missiles of the most ponderous practicable dimensions, constructed guns of mammoth proportions to contain those missiles. It was soon found, however, that those guns were too heavy for transportation or manoeuvring, and their shot too heavy for handling with that facility essential to rapid firing. Both guns and shot were therefore reduced in calibre and dimensions ; and for the shot, a denser ma- terial, iron, was introduced. Iron shot first came in use about the year 1490. Leaden shot, still more dense than iron, were, as has been remarked, employed at an earlier date ; but that substance proved too soft, as well as too costly. In reducing the calibre of guns, the world proceed- ed from one extreme to another, and until within twenty years regarded the 18-pdr. as that which af- forded the happy mean, between too light a gun on the one hand for effect, and too great weight on the other for convenient manoeuvring of gun or rapid ma- nipulation of shot. Accordingly, the long 18-pdr. came into general use as the favorite battering-piece. The next higher calibre was occasionally used on the lower decks of heavy ships, whose antagonists commonly had thick sides, requiring shot of greater penetration than the 18-pdr. But for the upper decks of ships, this favorite gun LNTEODUCTION OF THE CAEEONADE. 11 was found too heavy ; besides occupying, owing to its lengtli, too mucli room. Its weight straiaed the upper works, and injured the stability. Nine-pounders were therefore substituted on these decks. But that calibre did not give momentum, or weight of blow enough, for effect. This suggested the carronade, of great calibre and light weight, invented by General Mellville,* and introduced in 1790. A 32-pdr. carronade and car- riage weighs but little if any more than a long 9-pdr. and carriage. No weight was added, therefore, by substituting the 32-pdr. carronade for the long 9-pdr., but much was gained in effect, especially at short ranges. For when the percussive force of a 9-pound shot at its highest velocity from a long gun is only 14,000 pounds, that of a 32-pound shot from a caiTon- ade is 25,000 pounds, or nearly double. What the carronade lacked in accuracy, in consequence of its re- duced charge and length, was thought to be compen- sated by the greater niceness of its bore and the re- duced windage of its shot ; for the art of boring guns was formerly so imperfect, that a long gun could not be bored to admit safely the reduced windage admissi- ble in a shorter carronade. This distinction between the bores of can-onades and long guns, has not ceased to exist until within a few years ; and when existing, was not universally known. But although the principle of light guns having high calibres is good, and is still adhered to for upper batteries of large ships, and for small single-decked ships, it is generally questioned whether the reduction of weight in a carronade has not been carried too far. This question is more especially raised in regard to that gun as a battery for single-decked ships, or as an * More properly deduced from his invention of a 68-pouiider, Tvitli the make and proportions of a carronade. 1 2 , THE UNITED STATES AND BRITISH AEM AMENTS. entire battery for any sLip ; because, if engaged with an enemy having guns of greater range, altliougli in number of guns and all other respects inferior, it may be in his jDower to take a distant jDosition, and cut up an antagonist with impunity. This happened during the war with England, especially to sloops armed with that paltry piece, the 18-pounder can'onade. That gun and nearly all carronades under the calibre of 32- pdi's., have, therefore, gone into general disuse. Retaining the principle of the can-onade, the prac- tice under it is kept Avithin more moderate limits ; and light guns are cast noAV with an increased proportion of metal as compared with the shot. The carronade has about 60 or YO pounds of metal for every j)Ound in the shot ; few guns are now cast with less than 100 pounds of metal to one pound of shot. This increase of metal admits of heavier charges, which give in- creased range of shot, and still more increased accu- racy, so that no vessel can take an effective position^ and be herself ^^'holly out of harm's way. The exjoerience of our war with Great Britain taught another lesson, which, strange to say, many people are still blind to.* That lesson was, that if the long 1 8-pdr. be a " happy medium," the then prevail- ing phrase, the long 24:-2)dr., with which our frigates were armed, was still happier ; for the " United States" and other frigates, owing in a measure to this differ- ence in calibre, cut up their antagonists most dread- fully, without themselves receiving corresponding dam- age. Profiting by this lesson, both we and the British * This, like many other assertions in the text, was eminently true when the first edition of this hook appeared, A. D. 1845 ; hut is less so of course now, under the interest excited hy that edition, and the knowl- edge it conveyed, followed hy other hooks produced at home, and the perusal of others from ahroad. AKGTJMElNrTS DST EELATION TO OEDNANCE. 13 now prefer the long 32-pdr., and some even the 42-pdi"., granting the superior momentum, range, and accuracy of the heavier calibre; and granting also that the ma- nipulating point is not exceeded in shot of those weights. Of course, if the former number of guns be re- tained, ships of increased capacity are required to carry the heavier battery, and the consequent increase of men, provisions, and shot. But supposing the ca- pacity of the vessel to remain the same, it is now thought better to have wide quarters, and carry a less number of large guns, than a greater number of small guns. There is, of course, a practical limit in this mat- ter, though it is not exactly determined. The 32-pdr. commands the most general preference, but there are strenuous advocates for the ■4:2-pdr. And some persons would carry the reduction of number and increase in size of guns, to a still more extraordinary extent. At all events, a higher calibre of gun is coming into use, with as much metal as is consistent with the capacity and stability of ships, and the strength of such crews as they can berth and pro\T[sion ; for these are elements which must be consulted in adapting bat- teries to ships, or ships to batteries.* In what precedes, is stated only some of the popu- lar arguments in relation to the adaptation of ordnance to ships. But there are known and fixed laws govern- ing, and arising from, the motions of projectiles ; and it is by an investigation of these laws, and their appli- cations in the construction and use of guns, that the most certain and effective results are reached.f * No single-decked ship can terth 300 men with the decent comfort necessary to health. t The author's purpose is to prepare and publish in an Appendix, a table of the calibres, weights, lengths, and other features of the guns (now obsolete and passed into history) which were used in the first quar- ter of this century, and with which the great battles of the sea since 1794 were fouffht. 14 ESTEETIA. SECTION II. MATTER AND MOTION. INEETIA OF MATTEE.— WEIGHT. SPECIFIC GRAV- ITY, OE DENSITY. — RELATION OF CAUSE AND EFFECT. ACTION AND KEACTION. — MOMENTUM, OE QUANTITY OF MOTION. — PARABOLIC THEOEY OF PEOJECTILES. — ATMOSPHEEIO RESISTANCE. — EFFECTS OF ATMOS- PHERIC RESISTANCE UPON BALLS OF DIFFEEENT DIAMETEES, DENSITIES, AND VELOCITIES. All material substances are composed of what is teclmically termed matter, whicli lias certain inherent properties. For the convenience of the student, the essential properties of matter and the laws of motion are here briefly reviewed, before proceeding to the immediate consideration of the subject under discus- sion. TKEHTIA. If matter be at rest, it will remain at rest until set in motion by the application of an external force. And if matter be in motion, it will continue in the same uniform motion, forever, in a right line, unless some force be exerted either to retard, or stop, or accelerate the body, or to change its direction. It is this disposition, if at rest to remain at rest, or if in motion to continue in motion with a uniform ve- locity and direction, which is the inertia, or vis inertia of matter. The term indicates the passiveness of mat- ter ; its disposition passively to obey, and continue in obedience, to the last force impressed. It follows, therefore, that the more matter a body possesses, the greater its inertia, and the greater the force necessary to overcome that inertia, and to produce either motion or rest. WEIGHT GEAVITT. 15 A common error restricts tte meaning of inertia to tlie disposition of bodies at rest to remain at rest ; but, as above stated, it is equally the disposition of bodies in motion to continue in motion. WEIGHT. GEAVITY. The weight of a body is its tendency to descend in a straight line towards the centre of the earth. This tendency is the result of the mutual attraction of the matter composing the earth and the matter composing the body ; but it is usual to conceive it as produced by the attractive force of the earth only, and to call this force gravity. The body moves towards the centre, not because of any virtue residing at the centre, but because that direction is the resultant of the attractions of all the particles composing the earth. The terms gravity and weight ought not to be, though they usually are, confounded. Gravity is the force applied to each particle of a body ; weight is the product of the gravity of a single particle by the number of particles. The force of gravity is the same for all bodies; the weights of different bodies are proportional to the quantities of matter which they contain. The force of gravity is inversely proportional to the square of the distance from, the centre of tJie earth. Hence, a body at one hundred miles above the surface will have less gravity than a body at the surface, but may have more weight in consequence of containing much more matter. Gravity acts upon bodies constantly., and acts equally whether they be in motion or at rest. The moment a body ceases to be supported by a force 16 SPECIFIC GEAVIXy, OR DENSITY. (lii-ectly opposed to gravity, (as a ball leaving the muz- zle of a gun,) the body will fall, and will continue to fall, ^Hth an accelerated velocity, until stopped or checked by an opposing force. SPECIFIC GEAVITT, OE DENSITY. The weights of bodies, as has been before said, are as their quantities of matter, without reference to the bulk in which it is disposed. If bodies have much matter in small bulk, as lead or gold, they are said, in common language, to be very heavy. If they have the same matter, or the same weight, in a larger bulk, as cork and other light woods, they are said to be very light. In the language of philosophy, these bod- ies have greater and less comparative specific gravities^ or densities. Greater and less density are the terms most commonly used to express the comparative spe- cific gra^dties of bodies, because it is evident that quality depends upon the relative compactness of the matter they contain. A bale of cotton, before put in the press, although larger, contains no more matter or weight than after it comes from the press, much re- duced in bulk. The pressed bale has increased specific gravity, or density; having the same matter in less bulk. A stone ball, or an iron shell, has less density than an iron solid shot, which has less density than a leaden ball ; because, in both cases, there is less matter in the same bulk. RELATION OF CAUSE AND EFFECT. In nature, every effect is the result of a cause, which, though perhaps not apparent, still exists, and may be found by investigation. Like causes vdll pro- actiojst and KEAcnosr. lY duce like effects, and varying causes will produce cor- respondingly varying effects. In gunnery, effects are constantly varying, when to appearance causes remain tlie same. But close observation and reason generally detect the causes, which, whether detected or not, of course exist, though their nature may be doubtful, and give rise to many theories. AOTTON ABTD KEACTION. Action and reaction are eqaal and in opposite di- rections. This is an unvarying law, very commonly lost sight of, but most important in its effects. A per- son pushing another is an illustration. Both may fall, provided the two be of equal weight ; and provided each be braced by his position of standing equally Avith the other. If a light person push a heavy one, the former, having least inertia to be overcome, will appear to yield most by reaction ; whilst the latter, haAong most inertia, may not perceptibly move. The converse of this is also true, that if a heavy person push a light one, the latter, having least inertia, will most readily move off, and with greatest velocity. A parallel case to this is the action and reaction of a gun and shot, as will be shown hereafter when treating of velocities of shot and recoil of guns. MOMENTUM, OR QUANTITY OF MOTION. As previously stated, bodies at rest will remain so unless a force be applied to produce motion ; and like causes produce like effects. The same force applied will, therefore, cause the same motion in a heavy body as in a light body. The apparent difference is this : the light body will receive a more rapid motion, and 18 PAEABOLIC THEORY OF PROJECTILES. the heavy body a slower motion. But the motion, or quantity of motion, or momentum (terms synonymous in philosophy) of the bodies will be the same. This momentiun is compounded of velocity and weight. Multiply these two elements, and whether a body be heavy and move slow, or light and move fast, the product is the momentum. Thus a 12-pound ball, with a velocity of 1,600 feet, moves with a force or momentum represented by 12x1,600=19,200 ; and a 24-pound ball, with a velocity of 800 feet, moves with a momentum represented by 24x800=19,200. The inotion of the two balls is precisely the same. The terms momsntum and inertia, applied to bod- ies in motion, must not be confounded. One is the force with which bodies move ; the other is their dis- position to continue in motion. PARABOLIC THEORY OF PROJECTILES. The place and track of a projectile in free space, may be accurately determined upon the same princi- ple that the track of a vessel is traced, a process like laying off the departure and latitude at unifoi-m pe- riods, and drawing a line through the points thus es- tablished. If a gun be placed at a, several feet above a hori- zontal plane Z» c at the earth's surface, and pointed at d, a shot from the gun, impelled by a charge of pow- der, takes motion as a projectile in the direction a d; and unless operated upon by some other force, will continue to move in that direction, through equal spaces in equal times, forever ; and at the end of the first second of time, will be found at 1", at the end of the second equal space of time at 2", at the end of the third second at 3", and so on. But the pro- PARABOLIC THEOEY OF PEOJECTILES. 19 jectile, immediately on leaving tlie gun, ceases to be supported, and is drawn by gravity towards the earth witli an accelerated ve- locity. Tlie projectile, in its flight, will fall to the plane h c, in precise- ly the same time that a similar body would reach that plane, if let fall perpendicularly from a to b. Bodies fall through about sixteen feet in the first second of time; and falling through longer times, the spaces are as the squares of the times. At the end, therefore, of the first second of time, a shot from the gun at a is at ^,16 feet below the plane a d ; at the end of the second equal time, the shot is at F^ 64 feet below; and at the end of the third sec- ond, at G, 144 feet be- low the plane ad ; and the curve di-awn through these points, is the track or trajectory described by the shot. Because the ordinates F 1", F 2", and G 3", c are as the squares of c 2 9x16=144 ft. 20 PARABOLIC THEORY OF PROJECTILES. their respective times, and "because these times are as the intercepted spaces a 1", a 2", and a 3", (Hutton's conic sections, theorem 8th, of the parahola,) the curve a, E, F, G, is a parabola. All the properties of this curve being known, from them it was supposed easy to calculate the flights and ranges of shot with cer- tainty. This, as applied to gunnery, is termed the para- bolic theory, and by it, early mathematicians calcu- lated the results which they believed ought to take place in artillery practice. But practice, with veloci- ties beyond 300 feet per second, disagreed most widely with this theory; which disagreement the philoso- phers long persisted in attributing to unskilfalness on the part of artillerists. So uniform a discrep- ancy, however, finally taught that some cause existed as an element which, in the calculations, had been overlooked. This element proved to be aPmospheric resistance^ acting as a constantly retarding force in op- position to the projecting force, and destroying that hypothesis in the theory which assumes equal spaces to be passed over in equal times ; for the ball, moving slower and slower in consequence of this resistance, the times of passing the equal spaces must be continu- ally increasing. The real curve described by the pro- jectile departs, therefore, more rapidly than the pa- rabola from the tangent line a d in the figure, and its range is, in consequence, very much reduced. Indeed, the smaller balls, projected with high velocities, in which case the difference between theory and practice is most observable, do not range a twentieth part the distance they would but for this atmospheric resist- ance. With large bodies especially, and velocities not exceeding 300 feet per second, the parabolic theory ATMOSPHERIC RESISTANCE. 21 and practice quite nearly agree. A stone thrown from the hand, or a stream of water from a fire-engine pipe, may describe nearly a parabola, because in both these cases the velocities are considerably below 300 feet per second. ATMOSPHERIC RESISTANCE. When a ball or other solid body is at rest, the atmosphere, pressing like all fluids equally in every direction, acts upon the ball before and behind alike. The ball is ia equilibrio ; the force on one side bal- ances that on the other. But if it moves with high velocity through the air, impinging upon the particles in front, these particles react and produce resistance. The air condenses also in front, and rarefies, or forms nearly a vacuum, behind ; so that, being pressed back from before by an increased force which is not bal- anced from behind, the eqiTilibrium of pressure is de- stroyed, and the ball yields, in a retarded velocity, to this constant opposition. If the ball moves with low velocity, air flows in behind to fill the opening nearly as fast as it forms, the equilibrium of pressure is nearly preserved, and consequently little or no retardation is experienced. But as the velocity increases, the space behind be- comes more and more imperfectly filled by the return- ing fluid ; until, when the velocity exceeds 1,600 feet per second, being the velocity with which air flows into a vacuum, the opening forms faster than it can be fllled ; nearly or quite a vacuum occurs in rear of the ball ; no part of the pressure before is balanced by a pressure behind, and the utmost retarding force of the atmosphere is exerted. Sixteen hundred feet per sec- ond is, therefore, the maximum velocity which it is 22 ATMOSPHEEIC RESISTANCE. ever considered expedient to give a cannon ball ; for if, tlirougli great projectile force, a liiglier velocity be given, it is immediatey reduced to that by the enor- mous accumulated resistance of the atmosphere acting on its front. The tiieasure of atmospheric resistance, is the differ- ence between the pressure before and the pressure be- hind the ball. Rules, drawn from the parabolic theory for deter- mining the velocity and range of cannon balls, are ex- ploded, or are useless, except to demonstrate the amount of atmospheric resistance. As will hereafter be shown, velocities and ranges are obtained by ex- periments vdth balls of different diameters and densi- ties, projected with various proportional charges of powder. EFFECT OF ATMOSPHEEIC EESISTANCE UPON BALLS OF DIFFERENT BIA3IETEES, DENSITIES, AND VELOCITIES. By the parabolic theory, large and small, heavy and light balls, when projected with equal velocities and elevations, have equal ranges ; and when projected with different velocities, the ranges are directly as the velocities. In practice, however, this is not the case ; and ex- periments prove, 1st, that large balls have greater range than small balls of the same density and same initial velocity; 2d, that heavy or dense balls (as solid iron shot) have greater range than those less dense (as shells or stone balls), projected with equal velocity and elevation ; and 3d, that if balls of equal diameter and density be projected -with different velocities, those with low velocity will range farthest in propor- tion to the velocity. ATMOSPKEPvIC PvESISTANCE. 23 As it is atmospheric resistance alone wMcli occa- sions this difference, it follows : 1st. That this resistance acts with greater effect in retarding small balls than it does in retarding large ones. 2d. That it acts with greater effect in retarding balls of little density than it does in retarding those of great density. 3d. That it acts with greater proportional effect in retarding balls with high velocity than it does in retarding those with low velocity. The theory of atmospheric resistance accords pre- cisely with these phenomena, and explains them most satisfactorily. 1st. The effective resistance to small balls is greater than to large, because the absolute resistances they both meet, being upon the surfaces, are (velocities being equal) as the extent of those surfaces, which are as the squares of the diameters of the balls ; and their forces to overcome resistance are as their weights, which are as the cvhes of the diameters. Therefore, as cannon balls increase in diameter, their force to overcome atmospheric resistance increases faster than the resistance itself increases, and the large ball is less retarded than the small one. Examples in squaring and cubing a few trial num- bers, will illustrate the more rapid increase of the cubes than the squares. Take, for instance, two balls, one of 3, the other of 6 inches diameter. These cor- respond nearly with 3-pdr. and 24-pdr. shot. The re- sistances to these shot are as the squares of 3 and 6, that is, as 9 to 36, or 1 to 4. Their forces to overcome these resistances are as their weights, or as 3 to 24, or 1 to 8 ; also as the cubes of the diameter 27 to 216, which is likewise as 1 to 8. In other words, the larger 2-i ATMOSPHBEIC EESISTANCE. of these balls meets a resistance four times greater than tte smaller, but has eight times the power to overcome the resistance, and consequently is retarded in its flight but half as much as the smaller ball. 2d. Dense balls are less retarded than light balls of equal diameter, because, suj'faces being equal, resist- ances are also equal ; but the overcoming force being as the weights, the heaviest ball is least retarded. 3d. Balls of low velocity are retarded less than those of high velocity, because, oAving to the less rare- fied air in rear of the slow ball, the diiference of pres- sure before and behind, which is the measure of re- sistance, becomes less. And from these it follows : 1st. That large balls will outrange small balls of equal density, projected with the same velocity and elevation ; for being less retarded, they go farther. But that large balls, projected with very low veloci- ties, will not outrange, and may even fall short of, small balls projected with high velocities. 2d. That dense balls will outrange those less dense of equal diameter and projected under like circum- stances ; for, having more force to overcome the same resistance, they must go further. But that dense balls, projected with very low velocities, will not outrange, and may even fall short of, lighter balls projected vn\h high velocities. 3d. That when balls of equal density and diame- ter are projected with equal elevation and unequal velocities, the ball having highest velocity will outrange that having lowest velocity, but a^tII not outrange it to an extent proportioned to the difference of velocity ; for, resistance to high velocity being greater than that to low, its constant tendency is to equalize the veloci- ties ; so that, although in the beginning of its flight EECAPITULATION". "Jb the ball having high velocity gains fast on that having low, the gain is continually less and less, and in the end the velocities of the two may be nearly alike. All the difference in their ranges depends, therefore, upon what one has gained on the other in the first part of the flight. These are fundamental principles, on which all cor- rect practice in gunnery is based. They should be carefully studied, familiarly understood, and indelibly fixed in the mind. They have been tested over and over by Dr. Hutton, and since him by the most distin- guished officers in the English and French services, as well as by the most scientific of our own ; and any declarations of practice or experience that may be made, are not true, if discordant with these principles. When, therefore, as sometimes happens, results appar- ently at variance with them are obtained, it is certain that some error is committed, or some element over- looked. SECTION III. EEOAPITULATION. VELOCITY OF BALLS, INITIAL AND EEMAINING. — EXPERI- MENTS WITH THE BALLISTIC PENDITLirM. — THE EFFECT OF WEIGHT IN GUNS ON THEIK KECOIL, AND ON THE EANGE8 OF SHOT. — THE CELE- BKATED SUTTON HEATH PKACTIOE. EBLATIVE AOOUEACT OF DIFFEE- BNT CALIBEED GUNS AT DISTANT EANGES. EELATIVE PENETEATION OF SHOT OF DIFFBEENT DIAMETBES. — THE NATUEE OF BATTEET DE- TEEMINED BY EEASONING FEOM THE FOREGOING 0ON8IDEEATIONS, AND INTEODUOED, AS MOST PEOPEE FOR DIFFBEENT CLASSES OF VESSELS. In the preceding section, an attempt has been made to show : 1st. That a large solid shot should, and does, out- range a smaller shot of equal density, projected with similar velocity and elevation ; and that this result is 26 EECAPITrLATION. due to the less effective retardation which the large shot experiences from atmospheric resistance. 2d. That a solid shot should, and does, outrange a hollow shot or shell projected under like circum- stances; aad that this result is also due to the less effective retardation which the solid shot experiences from atmospheric resistance. 3d. That if balls of equal weight and diameter be projected with different velocities, those projected with the highest velocity will range farthest ; but that this increase of range Avill not be as great as the difference in velocity itself would indicate. This is due to the greater proportional retardation which the ball haviag higher velocity experiences from atmospheric resist- ance : the partial vacuum occasioned behind the ball by the flight of the rapid shot, being less readily filled by the returning fluid. 4th. That by the parabolic theory, which disre- gards atmospheric resistance, these differences in the ranges of large and small, heavy and light balls, ought not to exist ; and that, by this theory, increased ve- locity should give proportionably increased range. 5th. That up to about 300 feet per second of ve- locity, atmospheric resistance is so small, that the para- bolic theory may, in practice, be taken as nearly true. But that in the case of cannon balls, which are never intended to be thrown with an initial velocity much less than 800 feet per second, the parabolic theory does not apply, and is useless, except to demonstrate the amount of atmospheric resistance. If this attempt to render the foregoing funda- mental princi]3les clearly apparent has been successful, much is accomplished towards a correct ujiderstanding of the phenomena exhibited in the practice of gun- nery. VELOCITY OF BALLS, INITLAX AKD KEMALNXNG. 27 VELOCITIES OF BALLS. The velocity of a ball is tlie rapidity of its flight, and is measured by the rate per second at which it moves. Thus, if a ball be said to have 1,600 feet per second velocity, it is not meant that the ball actually passes through 1,600 feet in the second ; but at a given instant, moves with a rate which, if continued, would produce that result. But for atmospheric resistance, a ball moving at the rate of 1,600 feet per second would, as has been shown, actually pass through 1,600 feet in that second. Moving, however, as it does, against enonnous opposi- tion, the velocity which might at the beginning of a second have been at the rate of 1,600 feet, at the end of that second may be reduced to 1,000 feet, and con- sequently the ball have, in the second, moved through a much less space than 1,600 feet. Initial velocity, is the rate per second at which a ball moves at the beginning of its flight, immediatel}' on leaving the muzzle of a gun, or as near to the muzzle as the velocity can be ascertained — usually about 40 feet. Memaiiiing velocity, is the rate with which a ball moves at any specified point in its flight, after having been subjected to the retarding force of atmospheric resistance. Striking velocity, is that with which the ball strikes an object. The velocities of cannon balls cannot be deduced directly by mathematical calculation ; but experiment has ascertained the initial velocities due to certain proportional charges of powder, and the remaining velocities at dijSferent distances. And from these a 28 BALLISTIC PENDULUM. formula has been constructed, loy wliiclt botli initial and remaining velocities may be approximately calcu- lated. EXPERIMENTS WITH THE BALLISTIC PENDULUM. The first accurate and systematic experiments in gunner}', for determining velocities, were undertaken by Mr. Robins, in England, in the year 1Y40. These were repeated and greatly amplified by Dr. Hutton, in the years intervening between 1Y85 and 1*795. Both Mr. Robins and Dr. Hutton adopted the same means for determining effects and ascertaining results. Their instrument of determination was the ballistic pendulum, invented by Mr. Robins, and modified by ' Dr. Hutton and subsequent experimenters. The pen- dulum consisted of an enormous block of wood, sus- pended by iron rods of considerable length. A gun, loaded, j)laced with its muzzle a few feet (not over 40) from the block, and pointed at its centre, is discharged. The ball strikes and penetrates the pendulum block, and remaining buried there, communicates its momen- tum to the block. If, then, the momentum which the block takes can be measured, that of the shot when it struck the block is also known. And, since the mo- mentum is the product of the weight and velocity, the velocity of the ball will be found by dividing the mo- mentum by the known weight of the ball. To determine the momentum of the pendulum is a simple process, and is easily explained in principle, though requiring much nicety in practice. The weight of the pendulum block is known, to Avhich is added the weight of the shot which pene- trates it, and thus the aggregate weight is ascertained. It only remains, then, to get the velocity with which BALLISTIC PENDULUM. 29 the pendulum is set in motion, in order, by multiply- ing that velocity into its weight, to get its whole mo- mentum. In the following diagram, let a be the centre of oscillation of a pendulum, and b the centre of suspen- sion. When a ball strikes the pendidum block, giving it motion, a moves up the arc a c to c, the degrees of which are indicated by the pointer v' moving up to the point v", and marking its extent of movement on a graduated arc v' v". In order to reach c, a starts with the same velocity that, if let fall from c through the arc c a, it would have acquired on reaching the point a ; which velocity is the same that would have been acquired by the block if let fall freely through the perpendicular space d a, the versed sine of a c or half the arc of vibration. (Propositions 27, 28, and 29, Hutton's Mechanics.) The proportion of the space d aio the radius h a, is known from the table of natural sines ; but to know the length of 6? a in feet, it is first necessary to know the length in feet of the ra- dius ha ; or the distance of «, the centre of oscillation, from 5, the centre of sus- pension. This radius is obtained from the experi- ment itself, thus : when the pendulum is set in motion by the shot's blow, count the number of its vibrations in a minute of time. The lengths of pen- dulums are inversely as the squares of the niunber of vibrations they make 30 BALUSTIO PENDULUM, in a given time. (Corol. 2d, Prop. 29, Hutton's Me- chaDics.)* A pendulum vibrating 60 times in a minute is known by experiment to be 39| incbes long : therefore, n being tbe number of vibrations counted 39|X60' in a minute, we nave n^ : 60 : : 39-i- : b a= -2 — incbes. Tbis fourtb proportional, reduced to feet by- dividing by 12, gives for the value of the radius h a 11*737.5 the expression j"' fe^t, from which d a will be found by multiplying by the tabular (decimal) versed sine of the arc a c. The velocities acquired by falling bodies are as the square roots of the spaces through which they fall, (Scholium, Prop. 6, Hutton's Mechanics,) and they are known to fall through IGyV feet in one second of time, and in falling through that space, to acquire a velocity equal to the rate of 32-1- feet per second. Therefore, say, as \/\Q^^ : 32-i- : : \/~da to a fourth proportional, which is the velocity communicated to the pendulum by the shot. Multiply this velocity by the weight of the pendu- lum, and divide the product by the weight of the shot, and the quotient is the velocity the shot had in feet per second, when it struck the pendulum.f A method early in use, and sometimes practised now for determining, not the actual velocity, but the space passed through by a ball in a given time, say , one second, after leaving the muzzle of a gun, is, to place the axis of the gun horizontally 16 feet above the level of the ground over which it is intended to * All the references to Hutton are to the New York edition, edited by Mr. Adrian. t The student may find it convenient to have the precepts of the text condensed into a single formula, prepared for the author hy Prof. Chan- WEIGHT AKD EECOIL. 31 fire. A ball falls througli 16 feet in a second. It fol- lows, therefore, that if tlie ball bas left tbe muzzle iu tbe axis of tbe bore, wben it first grazes tbe ground it is one second from tbe gun ; and tbe space, measured from tbe gun to tbe graze, is tbat wbicb tbe ball bas passed tbrougb in a second. The liability of the shot to deflect upwards or downwards from the muzzle, and the irregular resistance of the atmosphere, destroy the accuracy of this method of determination. THE EFFECT OF WEIGHT EST GTJNS OK THEIR EECOIL. Since action and reaction are equal and in opposite directions, tbe charge of powder is reacted upon by tbe shot ; and this reaction of tbe shot upon the pow- der is conveyed, tbrougb tbe medium of that fluid, to the gun, causing tbe gun to recoil from the shot with a momentum nearly equal to tbat which tbe shot bas received from tbe powder. In general, all tbe momen- venet, then of the Naval School, Philadelphia, since become one of the most distinguished mathematicians of America. For this convenience, then, let V represent the velocity of the hall. A " " arc, described by the pendulum. n " " number of vibrations in one minute. w " " the weight of the ball. W " " weight of the pendulum. Then combining the several steps of the process, and reducing all the constants to a single number, we shall find V= — i— X X V (versm. A.) w n Wlience the velocity of the ball may be directly determined when W, w, n, and A are given by the experiment. Ummple.— Given Tr=600 lb., w=3 lb., m=30, A=20° log. versin., 20°=8.78037. log. 868.98=2.93901 ;r-l-w^_603_ ^g_^ log. v/ (versin. 20°)=9.39018 icXn 3X30 ^ ^ ^ log. 6.7=0.82607 F=1430fe6t. log. F=8.15526 32 WEIGHT AND RECOIL. turn the sliot has in one direction, the gun takes in an opposite direction. This is what is termed recoil of the gun. The weight and velocity of the ball being known, their product is its momentum ; which is also the momentum of the gun's recoil. Divide the mo- mentum of recoil by the weight of gun, and the quo- tient is the velocity of recoil. The charge of powder and weight of ball, which are the causes of recoil, re- maining the same, the effect, or momentum of recoil, also remains the same.* But as the weight of gun, or the divisor diminishes, the quotient, or velocity of re- coil increases. And this explains why light guns, that is guns light in proportion to their weight of ball, recoil more rapidly and violently, or as it is termed are more vicious than guns heavy in propor- tion to their weight of ball. Thus, suppose that a ten-pound charge of powder will give to a 32-pdr. ball 1,600 feet initial velocity per second. The whole mo- mentum of the ball then is 32xl,600=:51,200, which is also the momentum of recoil. The initial velocity of recoil is the momentum of recoil, 51,200, divided by the weight of gun. If this weight be 6,400 pounds, the quotient is 8 feet per second initial velocity of re- coil. But if the gun from which the discharge takes place be lighter, say 4,800 pounds, then the divisor being less, the quotient or velocity of recoil will be greater, and in this case reach nearly 11 feet per second, unless the charge is reduced. EFFECT OF WEIGHT EST GUNS OW THE RANGES OF SHOT. The velocity of a ball depends upon the quantity and strength of powder by which it is projected, and * There is some recoil with no shot placed in the gun. This is from the column of air, which affords a considerable resistance. WEIGHT AlfD EANGE. 33 has no direct relation to the weight of gun. A high proportional charge of powder will produce high velocity and range; and Avill produce this effect, whether from a light or from a heavy gun. But if this velocity of shot be produced from a light gun, its velocity in recoil may hecome so great that no breech- ing can confine the extent of recoil within the limited space afforded by a ship's deck. Hence it is, that light guns must, to keep their recoil within manageable limits, have light charges of powder ; which light charges, and not the weight of guns, is the direct cause of the reduced range of shot fired from guns light in proportion to their shot. It was supposed, that the quick recoil of light guns had the effect to decrease the range of shot fired from them; and that heavy guns, which recoil less, would, with the same charge of powder, give greater range. To test this point, Dr. Hutton, by direction of the British government, instituted a set of experiments in 1795. He slung a light gun in chains, so that it might have free recoil. Firing this gun, he accurately noted velocity and range ; also the recoil in arc. He then successively increased the weight of the gun, by lashing to it bars of iron ; and again firing successively with the same charge, noted the recoil and range at each discharge. Finally, he secm'ed the gun so that it could have no recoil. By these experiments Dr. Hut- ton determined, that as the weight of gun increases, the quickness and extent of recoil decrease ; but that decreased extent, or absolutely no recoil, has no effect on the velocity and range of shot. There has been on this subject, extensively existing in the navy, a popular error, so firmly rooted as to 34 SUTl-ON HEATH PRACTICE. yield -^vitli reluctance even to so Mgli authority as that of Dr. Hutton.* THE CELEBRATED St^TTON HEATH PRACTICE. "With a single exception, all the practice which has ever been habitually regarded as authoritative, con- fu-ms the theories and principles here laid down in re- spect to the greater range of heavy shot of high cali- bre, and the range and recoil of light guns. The exception alluded to is the practice at Sutton Heath, conducted by Major Elliot in 1810, and de- scribed in Sir Howard Dousrlas' earliest editions of naval gunnery. In that practice. Major Elliot used a long 24-pdr. of 9 feet 6 inches ; a long 18-pdr. of the same length ; and a light 24-pdr. of 6 feet 6 inches. He found the long 18-pdr. to have the greatest range, which then misled Sir Howard and many other distinguished minds, and is believed to have been the basis of the continued prejudice until lately existing in favor of 18-pdr. long guns.. To that prejudice the English now attribute the loss of the naval battles of the last war, in cases where British 18-pdrs. were opposed to Amer- ican 24-pdrs.f * It is a question, whether the irregular directions of recoil occasioned hy roughness of the platform or unequal obstruction of the trucks, affect the accuracy of firing. Dr. Hutton shows hy calculation, that a long gun recoils hut -i of an inch before the shot is free from the muzzle, and there- fore concludes that irregular recoil produces no effect upon accuracy. But Captain Simmons unequivocally pronounces a contrary opinion as the result of experiments made to test the question. With rifled cannon a rough platform is said to affect results materially. t We adopted the idea of a high-caUbred gun from the French, who were early impressed with its superiority. We also gave to guns gen- erally greater proportional weight — and this was especially the case with carronades — than the English gave to their guns of similar kind. Hence our breeching stood better ; and we hear less of carronades flying round and " looking their crews in the face." CALIBEE AND ACCUKACY. 35 Captain Simmons, in his excellent work, has ex- posed the discrepancies of the Sutton Heath practice, its incompatibility with established laws, and conse- quent error of results. EELATIVE ACCTJBACY OP DIFFEEENT CALIBEED GUNS AT DISTANT EANGES. From experiments made in Europe, a law of accu- racy of firing, or chances of hitting ^t distant ranges Avith guns of different calibre, has been deduced. The law is stated thus : at a thousand yards distant, the probabilities of hitting a given o1)ject are as the squares of the diameters of the balls, supposing all to be of equal density, and fired with equal proportional charges. By this law, different calibred guns should, in a given number of discharges, strike an object at 1,000 yards in the following proportions, viz. : the 42- pdr. 11 times ; the 32-pdr. 9 times ; the 24-pdr. Yi times; and the 18-pdr. 6 times. By another series of experiments continued through nine years at Strasbourg and Metz, from 1816 to 1825, it appears that the probabilities of hitting with guns of different calibre at 1,000 yards are in a ratio still more favorable to the high calibre than results from the law just stated. EELATIVE PENETEATIONS OF SHOT OE THE SAJIE DEN- SITY AND DIFEEEENT DIAMETEES. On the subject of penetration. Captain Simmons justly remarks that it is of paramount importance, and deserving of particular notice. He says, the penetrations of shot are not propor- tional to their momenta, or quantities of motion, which 3 36 PENETRATION. are as the cubes of the diameters ; but density and ve- locity being equal, the penetrations are directly as the diameters. And he further observes, that in the ser- vice of artillery in the field, range and accuracy are in general the only circumstances requiring attention; for, if the shot be sent home with precision, its mo- mentum must be ample against men and horses un- covered ; hitting, not penetrating, being there the con- sideration of consequence. Far different is the case, however, in naval warfare. A shot may, by passing in at a port or between the timbers of a ship, produce great effect, although its velocity may be low ; but commonly speaking, shot, to be effective against a ship, must have power to break through her sides at their thickest and most solid parts. In a subsequent division of the subject, it will be shown what striking velocity shot of different weights must have to perforate sides of different thicknesses. It is sufficient now to restate the general law of pene- tration to be, that shot of different diameters, density and striking velocity being equal, penetrate in similar materials to depths which are directly as the diam- eters. THE NATURE OF BATTEET, FOE DIPEEEENT CLASSES OF VESSELS. It follows from the foregoing considerations, that the qualities of great importance in a ship's battery, viz., range, accuracy, and penetration, are possessed in the highest degree by that battery which is composed of guns of the highest calibre, and having greatest weight in proportion to the weight of their projectile. But in adapting batteries to ships, or ships to bat- teries, there are practical limits to be observed, which BATTEELES FOR SHIPS. 37 restrict botli the calibre, the weight, and tlie nmnber of guns. The calibre is restricted by the impossibility of rapidly handling shot greater in weight than from 32 to 64 pounds, for loading broadside guns mounted in port-holes.* The 32-pdr. is the more common limit, the 42-pdr. has strenuous advocates, and the 64-pdi'. has come into some use. And in steamers, where rapidity of loading is of less consequence than delib- erate firing, and accuracy at considerable ranges, the 10-inch shell, weighing upwards of 100 pounds, and even the 11 -inch shell, have been introduced. The total weight of a battery is restricted by the stability of the ship and her capacity to carry that weight, and the water, provisions, and crew, which must generally bear a constant proportion to the weight of battery. The number of guns in a battery depends upon the weight which shall be given to each gun ; and the question is, whether the total weight shall be put in a large number of small guns, or in a small number of large guns. And Avhen the weight of gun is deter- mined, the next question is, what calibre of gun shall the metal be formed to ? For example, if it be deter- mined to divide the weight, so as to give each gun in a battery about 60 cwt. of metal, the question may * The shell for a 9-inch broadside gun weighs, when loaded, fused, and the sabot strapped on, about 73 pounds. That giiii seems to be growing in popular favor, although at first regarded doubtfully. Will it bear solid shot for battering forts ? Apparently it ought, with a reduced charge of powder. Such solid shot would weigh by calculation about 89 pounds. Thus, a 42-ponnd shot being 7 inches, the statement in propor- tion is, as 7^ : to 9^ : : 42 : 89. Divide the square of the gun's weight (9,000 lbs.) by 120,000 times the weight of the shot, (89 lbs.,) and the quotient is 1\ lbs., or the appropriate weight of the charge of powder, will exceed -jL the shot, say 2 lbs. less than the prescribed charge when loaded with the 73-lb. shell. The carronade charge was -Jj the shot. 38 BATTERIES FOE SHIPS. be, shall that amount be formed to a long 32-pdr., Avbicli is about 200 times heavier than its shot, or to an 8-inch 64-pdr. gun, which is about 100 times heavier than its solid ball? or, as another example, if it be determined to give each gun about 4,800 pounds weight, whether that weight shall be in a long 24-pdr. gun, which is 200 times heavier than its shot, or in a medium 32-pdr., which is 150 times heavier. For broadside fighting at very close action, the distribution of weight into guns 100 times heavier than their shot is thought most effective, provided there be room in the broadside for the number of guns such a distribution would produce, without crowding. On the other hand, for distant and espe- cially accurate firing at chasing or manoeuvring ranges, the distribution is most advantageously made in guns 200 times heavier than their shot; because, as has been shown, such guns bear heavier charges of pow- der, and give more velocity and consequent accuracy at a distance. Perhaps the gun 140 or 150 times heavier than its shot, or its shell if a shell-gim, is a judicious mean, combining, in the most advantageous degree, efficiency in close action, and accuracy at the greatest broadside fighting distances ; though in all such batteries there are usually two or more guns on each side of equal or greater calibre, of the heavier proportions, for pur- poses of deliberate accurate shooting at long range. This medium gun, if of high calibre, with 150 pounds of metal to the pound of shot, gives velocity and penetration enough for accuracy and execution at dis- tances in which ordinary aim can be depended on, and is therefore heavy enough for those distances. Beyond 600 or 800, perhaps 1,000 or 1,200 yards, it is regarded by experienced commanders as unwise to fire hi^oad- BATTERIES FOR SHIPS. 39 sides and throw away sliot. If vessels continue be- yond that distance and do not close, it is presumed they are either raanoeuvring with some object in view, or that one chases the other. For these chasing or manoeuvring ranges, it is supposed better marksmen, nicer adjustment of sights, and cooler and more delib- erate aim are introduced, requiring the heavier long gun of corresponding accuracy. This heavy gun of about 200 to 1, called usually the double-fortified gun, when employed for distant firing much exceeds in accuracy, but not so much in range, the medium gun of a similar calibre. The stUl lighter gun, however, with but a little over 100 pounds of metal to 1 of shot, is inferior in both respects, not only to long guns of the same calibre, but, especially in point of accuracy, to heavy long guns of a calibre somewhat lower — elevations being equal. The carronade, which is only about 60 or 70 times heavier than its shot, is too light for either range, ac- curacy, or great penetration, and is therefore fast going out of use. The 10-inch guns cast for the heavy steam- ers, have about the proportion of metal which the car- ronade has, and they are more effective than the car- ronade, only because of the greater weight and diame- ter of their projectile.* In accordance with this reasoning, foreign nations have, in many cases, substituted the medium gun of the next higher calibre for the long gun of the same weight formerly carried ; that is, many of the old 24- pdr. fiigates now carry medium 32-pdrs. of the same weight ; and it has been questioned whether, upon like principles, our own 32-pdr. frigates would not be ren- dered more effective by reaming up their 32-pdr. long * This 10-incli gun is obsolete. Tlie new one now in ijse is heavier, being, like the 9-inch, about 120 pour^ds heavier than its shell projectile. 40 CONSTBTJCTION OF GUNS. guns, constituting them medium 42-pdrs., and placing four or six long ^"l-pdr-s. in the same battery. Carronades of the calibre of 32-pdrs., which formed the batteries of small sloops, have been replaced by a gun of the same calibre having more metal and length. The large class sloops are armed with the medium 32-pdr., and four 55-cwt. 8-inch guns carried amid- ships. Steamers have hitherto been armed chiefly with the 8-inch shell-gun of only 63 cwt. This latter gun gives way to the 9-inch in broadside, and to the 64-pdr. solid shot double-fortified 8-inch gun, or the new 10 or the 11 -inch, for pivots. SECTION IV. OONSTKTJOTION, PEOOF, nSTSPECTION, AND PEESEEVATION OF GIINS. — OON- STEUCTION AKD EQUIPMENT OF OU^ OAEEIAGES. NOMENCLATUEE. Iw describing a subject like the present, technicalities, or conventional terms, necessarily arise. They consti- tute what is termed nomenclature ; a clear understand- ing of which, as an elementary step, is altogether in- dispensable. The extreme length of a gun {.see figure, p. 41) is af, measured from a, at the rear of the cascable, along the axis of the bore to/, at the face of the muzzle. The length of a gun is h /, measured from the rear f the base-ring ^, along the axis of the bore, (or a line parallel to the axis,) to the face of the muzzle/. The length of lore is h f measured from the bottom of the bore h, to the face of the muzzle. o: CONSTRTJCnON OF GUNS. 41 c ? The preponderance of a gun, is tliat weight wMcli, liiiiig at the inii2;zle, will balance the breech, when the trunnions rest on knife-edge sus- pensions. Breech preponderance^ or pre- ponderance measured at the breech, is the weight of the breech over that of the muzzle, as determined by steel yards when the trunnions rest on knife-edges. The dispart of a gun, is half the difference of the breech and muzzle diameters. Calibre of a gun, is the di- ameter of its bore expressed in inches. Ordinarily, however, the weight of the solid shot thrown by a gun is used to ex- press its calibre ; as a gun of the calibre of 32, 42, or 64, which measure respectively 6.4, 7, and 7.9 inches in diameter. The whole gun, in its ex- ternal aspect, is divided into five parts : 1st. The cascahle h a, meas- ured back from the rear of the base-ring b. This space is sub- divided into the base of breech 1, the nech 2, and the hnob 3, of the cascable. 2d. The first reinforce h c, is measured from 5, the rear of the base-ring, to the line c, which is at the end of the 42 CONSTRUCTION OF GUNS. cylinder, or at tlie small diameter of tlie first cone. In all old guns the first reinforce was conical in form ; in the new guns it is cylindrical. In this part is placed the venPpatcli v ; also the vent-field 4, which is a zone about the gun at that part, equal in width to the length of the vent-patch. 3d. The second reinforce c d, which is measured from the fore end of the first reinforce to the small diameter of the second cone. In this part are placed the trunnions t, and their rimbases. 4th. The cliase d «, which is measured from the fore end of the second reinforce (/, to the rear of the muzzle-ring e. 5th. The muzzle ef. In this is included the swell, or tulip of the muzzle.* CONSTRUCTION OF GUNS. In designing a gun for construction, the weight of metal it is to contain, and its calibre, are supposed prescribed by considerations hitherto discussed. The remaining question is, how shall this metal be disposed with a due reference to length of gun, thickness of parts, and position of trunnions, so as to secure at once the greatest degree of strength and efiiciency ? Manifestly, the thicknesses of metal at the breech and first reinforce must be sufficient to resist the ex- plosive eifort of the powder, which is greatest where the body of the charge ignites. Usually, the thickness at this part is equal to about one calibre. In the heaviest guns it frequently exceeds a calibre from a tenth to a fifth ; in lighter guns is sometimes a little * The Ordnance Regulations, Ed. 1860, Diagram F, succeeding page 162, give the nomenclature more minutely. The text, however, has the main features of a gun essential to be known. CONSTRUCTION OF GUNS. 43 below a calibre ; and in carronades about -f- of a cal- ibre. But tbe thickness, whatever it be at that part, is, when fixed upon, the unit from which the decrease towards the muzzle is estimated. The extent of this decrease at dififerent distances from the breech has been proportionally determined by experiments, which show the force to be resisted or confined at the different parts of a gun. Thus : by perforating a gun in several places, from the exterior to the bore, at right angles with it, and screwing a pistol-barrel containing a steel ball, first into one, then into another of these perforations, then loading the gun with powder and shot, and discharging it with the pistol-barrel successively at the different perforations, the relative velocities with which the steel pistol-ball is forced out at these different positions, indicate the force exerted there to burst the gun ; and consequently the relative strength of metal necessary in the various points to resist explosion.* The results of these experiments are relatively as follows in decimal parts : At one calibre in rear of the centre of the shot, . . .9758 At the centre of the shot, 1. At 1 calibre in front of the shot, 8149 2 calibres, " " 6767 3 " '• " " 6163 5 " " " " 5291 7 " " " " 4393 9 " " " " 3988 11 " " " " 3667 15 " " " " 2858 These decimals show the relative strength necessary at different parts to resist explosion. | * This method of determining the force exerted by a charge of powder with a ball, upon the gun at various parts along the bore, was the inven- tion of the late Colonel Bomford, a highly distinguished officer, long at the head of the ordnance corps of the army. t The Dahlgren gun is a judicious exaggeration of these proportions, 44 CONSTKUCTIOK OF GUNS. After aiTanging the thickness of metal with, regard to sufficient strengtli of parts, length of gun is desirable only as far as about 18 or 20 calibres ; because expe- rience proves that 18 calibres in length will burn the highest service charges used with shot in long guns, and less length the charges for medium guns ; also that a short caiTonade will burn the appropriate charge for that gun. If a double-fortified long gun were much shorter than 18 calibres, some of its charge might be blown out unbumed ; and so of the medium gun if reduced in length much below 16 calibres. The bore then must have length enough for this purpose of burning the whole charge ; beyond that, length is of compara- tively no consequence as regards range, for it increases only in proportion to the 5th root of the length; so that doubling the length gives but \ increase of range. On the other hand, the labor of running a gun out to battery after reloading, increases with the length of the gun. Therefore, make the gun, if the quantity of metal permit, long enough to burn the charge, and project sufficiently from the port ; but no longer. For this latter reason, viz., sufficiency of projection, guns of small calibre are usually cast longer and conse- quently heavier, in proportion, than guns of higher calibre. The long guns in service are in length from 16 calibres in the 42, to 20 calibres in the 18-pdr. — ^the guns of small calibre being nearly as long as those of large, (and consequently longer in proportion,) for the sake of equal projection beyond the port. Medium fasMoning tlie gun on the principle that, if it burst anywhere it shall he at some out-board rather than in-board part. On this principle, the rein- force at the seat of the charge is strengthened at the expense of the chase and muzzle, the metal being taken from the latter parts and added to the former. This question is, however, more elaborately treated in Part II., to which the reader is referred. CONSTEtrCTIOIf OF GUKS. 45 guns are 16 calibres and under, and carronades are 8 or 9 calibres in length. The thickness of metal through from the bottom of the bore, in the line of the axis of the gun, is of su- perior consequence ; for if a gun be weak there, strength in other parts will not save it from explosion. That thickness, measured from the bottom of the bore to the rear of the base-ring, is equal to or greater than the thickness given to the metal at the seat of the shot. To this is added whatever strength arises fi^om the form of the base of breech. Although the charge of a medium gun is less than that of a long gun, there is not a proportional decrease in the thickness of metal in the parts about the breech, because the quantity of powder actually igniting at that particular spot, (as will be shown under the head of loading guns,) may be nearly the same in a medium and in a long gun. In the former, less of the smaller charge ignites along the bore ; and in the latter, more of the large charge ignites along the bore ; for which reason increased length, as has been shown, is allowed to the latter, PKEPONDEEAKCE. TETHSnSTIONS. The regulation preponderance of trunnion guns is usually 2V ^^6 weight of the gun; preponderance being considered as that weight Avhich, if hung at the muzzle, will just balance the breech. The actual amount of preponderance depends evi- dently upon the relative positions of the centre of gravity of a gun and the axis of its trunnions. If the axis of the trunnions coincides with the centre of gravity, there will be no preponderance, and the muz- zle and breech -will balance exactly. And the farther 46 CONSTRUCTION OF GUNS. the trunnions are placed before the centre of gravity, the more heavily will the breech preponderate. Having then drafted the gun in reference to its length, thickness of parts, and bore, the centre of gravity must next be determined, which is done as follows : Divide the gun into as many parts as it has distinct figures. Determine the centre of gravity of each part, its weight, and the distance of its centre of gravity from the face of the muzzle. Multiply the weight of each part by the distance of its centre of gravity from the face of the muzzle ; add together the products ; divide their sum by the sum of the weights, and the quotient is the distance of the centre of gravity of the gun fi-om the face of the muzzle. To place the axis of the trunnions so as to give the gun the regulation preponderance of J-^- its weight, divide the space between the centre of gravity and face of the muzzle into 21 parts, and draw the axis of the trunnions at the distance of one of those parts before the centre of gravity, and twenty of them from the face of the muzzle. Then, upon the principle of the lever, f in the figure being the fulcrum, or position 1C23. of the trunnions ; c the centre of gravity of the gun, or the weight ; m the point of application of the bal- ancing power, or face of the muzzle ; and/ m equalling 20 times of; ^V P^^^^^ of c's weight, hung at m, will bal- ance c ; or -jV part the whole weight of the gun, hung at the miizzle, will balance the whole gun. Whether c m, in the figure, be considered an in- flexible bar resting on the fulcrum/, with the whole weight of the gun hung from c ; or c be the actual centre of gravity of the gun,/ the trunnions, and m CONSTEtrCTION OF GUNS. 4Y the muzzle ; it is the same thing in effect ; for in either case, G represents the whole weight of the gun, which is regarded as concentrated at the centre of gravitj^ Usually, tninnions are cast in diameter and length equal to a calibre ; and they must be placed with their axis precisely at right angles with that of the bore. Formerly, their axis was set below the centre of the gun ; and when so placed, the guns were said to be quarter huvg. The object was to give a clear, unob- structed side sight. The disadvantage proved to be, that guns so hung racked their carriages. The prac- tice, therefore, is generally discontinued, and guns are now cast centre hung / that is, have the axis of their trunnions passing through the axis of the bore. BOEE. The gun having been shaped or modelled on the principles described, a wooden pattern is made and moulded, and the gun cast in a solid mass without any space left at the centre. When taken from the flask in which it is cast, the gun goes into the boring- mill to be bored and to be turned off on some of the exterior parts. In the mill, the gun has no progressive motion, but continually revolves on its axis. The boring-bit, set in the axis of the gun produced, and having a sharp tool on the extremity, is uniformly pressed up to the gun, forming the bore with great exactness. Heavy double-fortified guns are always bored without chambers, and have, consequently, an equal diameter of bore throughout the whole length. The full diameter at the bottom of the bore* is necessar}' * By bottom of the bore is meant the extremity against which the powder is rammed in loading. The terra is also applied improperly to designate the under side of the bore when the vent is np. 48 CONSTKUCTION OF GUNS. to contain tlie full charge of a teavy gun, (| tlie weight of ball,) wHcli charge would otherwise be dispropor- tionately long. Besides, chambers are objectionable where they can as well be dispensed with, because they are made to contain just the fall charge; and when reduces are used, unless peculiar pains be taken, the shot, which lies only against the mouth of the chamber, may not reach the powder ; in which case, a vacant space would exist between the powder and ball. Chambers are not so easily sponged, either ; and unless the rammers are carefully made to fit, they sometimes wedge into the slope which connects the bore and chamber, occasioning considerable labor and delay to di'aw the rammer. But light guns usually have chambers ; the object of which is to give a greater thickaess of metal than obviously can be given if the full diameter of bore be carried through the whole length. Another object is to give a better proportion of length and diameter to the cylinder of a light charge of powder; for if its diameter were toO great as compared with its length, it Avould be as likely to roll as to slide home, and con- sequently as likely to reach its place with the tied end up as with the side up. The charge, for example, of a 42-pdr. carronade, 3 J pounds, put up in a globular form, would have a diameter of 6 inches. Seven inches is the diameter of the bore. Therefore, if that gun were not chambered, but the full diameter of the bore car- ried to the bottom, its charge would have equal length and diameter, and often go home with the mouth up. Another, and by many regarded as a chief reason, why the bores of guns should be chambered, is that by concentrating the whole action of the charge more nearly upon the centre of the shot, the force is sup- posed more effective in producing velocity. Some ex- CONSTRTJCTIOlir OF GUNS. 43 periments have certainly favored this idea ; and yet in England and France chambered guns are not generally approved except as shell-guns, in which lesser charges are used. The French equivalent for them are styled canons-obusiers. When the bore of a gun is chambered, there are three parts, which have each a distinct designation, viz., the cylinder^ the slope, and the chamber. The cylinder is the largest and long part of the bore ; the slope is the contraction which unites the cylinder and chamber ; and the chamber is the part, of reduced size, at the bottom, for containing the charge of powder. Its capacity must be sufficient to contain a full service charge. If the diameter be small, the length must be greater ; and the reverse. In service, the 8- inch guns have a diameter of chamber equal to that of the bore of a 32-pdr. gun; the chambers of the 32-pdr. guns have the same diameter as the bore of a 24-pdr. The chambers just described are of the French form, and mostly used also in our service. The Eng- lish use a form of chamber given to their light guns by General Millar, which is the old French " Gomer" chamber. It is a frustrum of a cone, from the point where the contraction commences to the bottom of the bore. Fig. 1 is a French and American chamber; a is d. the chamber, h the slope, and d the cylinder of the bore. 50 CONSTEUOTION OF QUNS. Fig. 2 is tLe " Gomer" or Englisli General Millar chamber. The bottoms of bores, whether chambered or not, are various in shape. Some are hemispherical ; but usually they are planes, with the corners cut off by curves struck to a radius equal to J the diameter at that part. COWCEWTEICITY. It is of the highest consequence, that the axis of the bore should coincide with the axis of the gun. To render this certain, whilst the gun remains fixed in the mill upon the centres on which it is bored, either the whole exterior of the gun is turned off, or only the j)rominent points on the two extremities, viz., the base-ring and the muzzle. If these are turned, it ren- ders the bore concentric with the prominent extremi- ties by which the sights are adjusted. But for this exact concentricity, the sights on a gun would never indicate the direction of the axis of the bore, and con- sequently would be of no real service in j)ointing guns accurately. It may be well here to speak of reamed-up gnns, of which mention has before been made. For exam- ple, if it be desired to make, from a long 24-pdr. gun, a medium chambered 32-pdr., the gun is put in the mill and the bore enlarged as far as the part intended to be left as a chamber. The point of diificulty in this operation, not always overcome, is, to get the gun in the lathe upon the same centres it was originally bored on, so that the gun, the cylinder of the bore, and the chamber shall be all concentric. In this re- spect some reamed guns have been carelessly treated — which, though, is not now of much consequence, for the old guns, instead of being reamed up, are broken up. CONSTRUCTION OF GUNS. 51 VHNT-PATCH OE LOCK-PIECE, AND VENT-HOLE. The vent-patcli on the gun at the top, is cast for the purpose of securing the lock. It is also a reinforce of metal to compensate for that taken out in boring the vent, which is drilled in the centre-line of this piece, sometimes at an angle of 70° with the axis of the bore for the sake of convenience in using the priming-wire, and sometimes vertically with the axis that the percussion-hammer may strike the wafer more fairly, or the friction-primer not come out when the string or wire is drawn. At the upper extremity, the vent is by regulation -^-^■■^ of an inch diameter, and tapers to -^\ at its lower orifice. Its junction with the bore is near, though not at, the bottom. The object is, to enter it so low that a reduced charge can never be wholly below it ; and again so far from the bottom of the bore that if a charge be not entirely home, it will not fail to ignite from the wafer, quill, or other priming. Some other reasons obtaining are as follows : Dr. Hutton made experiments, the results of which went to show that the popular notion respecting the more rapid ignition of a charge if the vent enter at its middle, is erroneous ; and that, whether the charge be ignited at either extremity, or in the middle, there is no perceptible difference in the ignition. Subsequently, however, to Dr. Hutton's experi- ments, others supposed more accurate were instituted at the French schools, which proved that both he and Count Rumford, who had arrived at similar conclu- sions, were in error ; and that the popular sentiment was in a measure correct. The error of those gentle- men arose from the fact, that their experiments were made with charges of powder extremely small as com- pared with the shot projected. 52 QUALITY OF lEON. The Frencli experiments with full charges of ^ the weight of ball, gave results as follows : When the vent entered \ the calibre from the bottom of the charge, it was found to give higher velocity to the ball than when entering at any other point. And when the vent entered at |- the length of the cartridge from its bottom, the greatest recoil of gun took place. Those experiments went further, and showed, 1st, that when the vent-hole was made through the casca- ble in a line with the axis of the bore, the instantane- ousness of ignition was so increased as to produce effects similar in violence to those which, it will here- after be shown, arise from the explosion, in a gun, of a charge of detonating powder, viz., to score the gun, break the shot, or give to it error of flight ; 2d, that when the vent was set at an angle of 30° with the bore, efi^ects, the same in kind, but not in degree, were produced ; and 3d, that when the vent was set at right angles with the axis of the bore, the parts of the charge ignited in succession, giving to the shot acceler- ated velocity, which produced no injury to the gun, and was favorable to the accuracy of the shot's flight. QUALITY AND WOKKING OF THE IKON FOR GUWS. The iron for casting guns must have been separated from the earthy matter with which it is found com- bined in the mines, smelted, by means of charcoal, or mineral coal perfectly free from sulphur ; for the effect of sulphur on iron is to harden it and impair its tenacity. Bituminous or anthracite coals entirely without this or some other deleterious quality, are of rare occxurence ; consequently, gun iron is mostly charcoal iron. "When smelted in the blast furnace, it is drawn off into moulds in the form of pigs. QUALITY or ERON. 53 That iron, the recent fracture of which presents a gray appearance, with coarse grain, and not much lus- tre, is reckoned most suitable for making guns, because fotmd by experience to possess greatest tenacity, though deficient in hardness ; and that with a small, white, shining grain, the contrary. In Sweden, guns are cast of iron drawn directly from the smelting furnace, without having gone into pigs. In other countries it is usual to cast from the first melting of the pigs. Recent interesting experi- ments go, however, to show, that iron from some, if not all of our mines, is improved in the qualities de- sirable for guns, viz., density, hardness, and tenacity, by being melted a third time, or the second time from the pigs. It is also a question much argued, whether, in. casting guns, the metal should, as soon as it is thor- oughly melted, be immediately run into the cannon- moulds ; or whether it should be longer retained in the furnace and exposed to a continued heat for several hours before drawn into the moulds. Recent experi- ments favor the idea of continuing the heat, or, as the phrase at the furnaces is, " working the iron higher." These questions are of most important interest, and along with others concerning the qualities of iron, what circumstances they arise from, whether of the ore, the smelting, or the working, and the rationale ; also the figure, moulding, casting, and cooling of the gun, will be found discussed somewhat elaborately in Part II. of this book. Beyond that, the reader is re- ferred to the Ordnance Report of the army, quarto, H. C. Baird, PMladelphia, I860.* * This, and all other military and naval publications, whether by in- dividuals or by the Government, it is useful to know, are readily obtained from an enterprising house in New York, which makes this branch a specialty — D. Van Nostrand, 192 Broadway. — Author. 54 INSPECTION AND PKOOF. INSPECTION AND PROOF OF GtJNg. When a gun has been taken from the boring-mill, trimmed off, and the trunnions and rimbases turned, it is placed with the trunnions resting on knife-edge sus- pensions for the purpose of determining the exact pre- ponderance. So placed, the weight which, hung at the muzzle, will balance the breech, is the true inspec- tion prepondeixince. A long 32-pdr. gun weighs about 6,800 pounds ; its required preponderance of -g-V, is 340 pounds. Upon inspection, therefore, when the gun is suspended by the trunnions, 340 pounds hung at the muzzle ought just to balance the breech. As, however, another method, that of weighing the breech Avith steel-yards, is often resorted to for obtain- ing preponderance ; and as of late there is a question raised as to what true preponderance is, to prevent mistakes, ordnance officers adopt the precaution of marking on the drawings the calculated preponderance at the breech corresponding with the regulation pre- ponderance at the muzzle. If the breech be weighed by steel-yards, they give the inspection preponderance at the hreecTi. And if the breech be balanced by a weight hung at the muzzle, that weight is the inspection preponderance at the muzzle. If, in the preponderance column of the proof table forms, the regulation preponderance entered is the muzzle preponderance, then the inspection preponder- ance determined and entered is presumed to be the muzzle preponderance ; for, otherwise, a large devia- tion from the regulations will appear, when in reality none may exist : the apparent variation arising from the fact, that the regulation preponderance is calculated rNSPECnON AJSTD PROOF. 55 from tlie muzzle, aBcl the inspection preponderance determined at the breech. When the former is ^V? 'the latter will commonly be, in the old-fashioned guns, about yV the weight of gun, owing to the difference in length before and behind the trunnions, these lengths being in about the proportions of 20 to 14. A simple diagram will render this apparent : Thus, if in the figures 1 and 2,/ be the fulcrum or Fig. 1. 9 f Fig. 2. axis of trunnions, c the centre of gravity of the gun, representing its whole weight there concentrated, m the muzzle, and h the breech; in Fig. 1, c/is to/m as 1 to 20 ; therefore, 1 pound at m balances 20 pounds at c. In figure 2,/ c is to/ 5 as 1 to 14. Therefore, 1 pound at h will sustain but 14 poimds at c; and the preponderance determined at the muzzle m. Fig. 1, •sviU be i-a ; and when determined at the breech J, Fig. 2, it will be Vt- Preponderance at the muzzle evidently does not indicate the weight in the breech to be overcome when depressing a gun. Preponderance at the breech does indicate this weight. Why muzzle preponderance should have been originally adopted as the technical signification, is nowhere explained. The presumed reason is, that it expresses the readiness with which the muzzle yields downwards to a blow from a shot upon the under side of the bore at the muzzle. It is this blow that, in firing, often occasions the muzzle to fall, and the breech to rise, and fall again with violence on 66 INSPECTION AND PKOOF. the quoin. If, in sucli case, the muzzle does not yield to the shot's blow, the shot wUl deflect upwards, and quit the muzzle at an elevation. On the other hand, if the muzzle yields, the shot will not rise. Like a person jumping from a platform which yields to the spring ; and again from a platform which is firmly se- cured and does not yield. Hence, guns having the greatest preponderance, or most difficult movement on the trunnions, may most frequently throw their shot at greater angles of elevation. Guns are next subjected to a most minute exam- ination for such defects as, in the casting or otherwise, the eye or instniments can discover. The external measurements are made, such as length, length of parts, diameters, length and diameter of trunnions, in all which there must be a very close conformity with the drawings furnished. The length of the bore is also measured, and the depth and forms of the slope and chamber in chambered guns. The form of the cham- ber and slope may be found with accuracy by taking an impression with oiled wax. By far the nicest part of inspection, however, is to get the exact diameter of the Iwre at points not more than a calibre apart throughout its whole length. To accomplish this, three instruments are used : the cylin- der-gauge, the calibre-gauge, and the calibre-plate. The cylinder-gauge is a perfectly-turned cylinder, of the exact prescribed diameter of the bore, and a calibre in length. If the bore be so small that this gauge will not pass through the whole length to the bottom, the gun is at once rejected, as in this respect defective. The calibre-plate is a circular plate of the minimum diameter of the bore, with a movable piece attached, and so contrived that it shows the excess of diameter INSPECTION AKD PROOF. 57 in the bore at any part, from 0.01 incli, to 0.04 inch, wHch. is the greatest excess allowed. The calibre-gauge is a trapezoidal plate of iron, made to measure the diameter at the muzzle. The bore is next searched for cavities ; first with the eye, aided by a lighted candle, put on a staflP and introduced, or by throwing into the bore a reflection of the bright sun Avith a looking-glass ; and second by an instrument called a seai'cher, which has steel points that press outwards by springs, and when pushed in or out, or turned in the bpre, will, if there be honey- combs, catch in them, and indicate their existence. Any cavity whatever within the gun causes its re- jection. A cavity on the exterior, exceeding J of an inch in depth, will also cause the gun to be rejected. Yet offi- cers often XLsed unreflectingly to permit guns cut much deeper than that, to fit on locks and sights. Such things, formerly not uncommon, are now looked on as surprising. It vnll hardly be credited, that guns were chiselled to fit the locks, and not the locks to fit guns ! Firing with excessive charges is then resorted to, for the purpose of testing the strength of a gun. The amount of this test is prescribed by the government upon the general principle, that the proof shall be great enough on the one hand to show in the gun un- doubted strength to sustain service charges; and on the other hand, not be so great as to strain a gun and render it by proof unfit for service. The gauge of shot used in proof is not to be forgotten or neglected. To avoid the hazard of injury to guns by proof, in some of the European services it is a practice to select indiscriminately, from a series, a certain number, and burst them. If those selected burst only by enor- mously excessive charges, it is taken as evidence of 58 LNSPECTION AND PKOOF. strength in the remainder of the series. This plan is generally regarded with partiality ; for, after all, prov- ing a gun proves little else than that it did not burst by the proof charge, not but that it may, at the next time of firing, burst with a much reduced charge ; and if the proof has been at all excessive, who may say that the gian has not been essentially weakened by it? Other tests of strength are resorted to ; hydrostatic pressure is one. It, as well as that of powder, may be excessive. When carried, as in some cases it has, to 9,000 pounds on a square inch, water was forced through the pores of the iron of a 24-pdr. Its princi- pal practical utility, when moderately applied, is to discover flaws in the casting, which the searcher put in the bore does not detect, for there will be a contin- ued oozing from them after the rest has become dry. Another is to cast a bar two inches square, and try its transverse strength. Another, to cut a plug from the face of the muzzle, and try its tensile strength by a machine which nips strongly the two ends and pulls them directly asunder ; and still a third, which tests the torsion, by both pulling and twisting at the same time. The sjjecific gravity of these fragments is also tested. So uniform is the relation between these and the powder test, that they have been regarded as safe guides in assisting to judge the reliability of guns for service, without risking injury by an excessive and conclusive powder-proof to every gun. It may be well here to observe, that the lifetime of a gun is set down at about 1,000 discharges. After having been fired with shot that number of times, a gun is commonly regarded as unfit for further use. A nut cracks only after several blows from a hammer ; and church-bells fracture sometimes after a hundred years or more of use, and without any increase of blow. PEESEEVATION OF GIUSTS. 59 So it is also with guns. In them, the cohesion of the metal is undoubtedly weakened, though it may be in an inconceivably small degree, by each discharge, either by the direct strain, or, as it is commonly said, by the effect of vibration upon the crystalline structure of the cast iron. iLiEKS ON Ginsrs. Guns that pass inspection, are marked with their weight, date of construction, foundry M'here cast, and initials of the responsible proving officer. Guns re- jected, bear marks to that effect prescribed by the Bureau. PEESEEVATION OF GUNS. When received and not required for immediate ser- vice, guns are placed for preservation in parks, on skids, with the muzzle lowest, and the vent-hole either up or on the side. The vent is plugged with a piece of greased hard wood. If the vent be placed down- wards, the dampness from condensation and from the ground soon rots the plug out. The muzzles are left open ; that is, the tompions are not put in. This is because dampness will collect in a gun by condensa- tion "when the gun is cooler than the air within, pre- cisely as dampness collects on the surface of a pitcher of cool water. And it will collect in the gun whether the tompion be in or out. But -^dth the tompion in, it cannot dry ; with the tompion out, the dampness dries, escaping by evaporation into the air. Or, if the tompion is in, it has a score cut for drainage. Formerly, too little attention was paid in the ser- vice to the preservation of guns, especially on board ships placed in ordinary. The vents were probably 60 MOUNTING GUNS. more neglected than otlier parts. By regulation, as has been seen, no vent over 0.25 inch is received ; and yet it was not uncommon to find guns, but a few years in service, with vents enlarged very much beyond that dimension. When quill tubes and matches were used for priming and firing guns, the only evil of enlarged vents was the escape of the force of powder from them, reducing by so much that which acts to project the shot. But since the introduction of percussion-wafers, or friction-primers, the additional evil is, that they will not explode uniformly and cei'tainly. 1^0 w, the organization of a Bureau of Ordnance, and under it a system operating throughout the ser- vice, with the supervision of officers at each station appointed exclusively to ordnance duties, has changed all this from culpable neglect of armaments and stores, to the most efiicient and praiseworthy care and ar- rangement. Guns are lacquered for preservation, both in the bore and on the exterior. It is said that the foulness produced by firing, is the best preventive against rust, and that this fact accounts for the little injury from rust which bores receive Avhen in ser^dce and occasion- ally discharged. It was once a practice to " scale " a ship's guns at certain intervals, probably with some such idea. MOUNTING GUNS IN SHIPS' POETS. The lower guns of a ship are usually carried from 6. to 9 feet from the water. This establishes nearly the centre of the port-hole. Ports are commonly 3 feet high and 3 J feet wide. The gun-deck is usually laid from 20 to 24 inches below the bottom of the port ; the space between the water-way and inner port-sill being termed the " spurketing." GUK CAKKIA&ES. 61 In mounting gnns, tte rule is to place tlie centre of the trunnions in a horizontal plane wMcli is lialf a calibre below tlie centre of tbe port. Consequently, tbe gun carriage must be Idgh. enough, to sustain a gun in that position. The object of giving more space in the port above than below the gun, is that it may have, as it requires, more elevation than depression. This size of port and position of gun admit about 11° of elevation, and 7" of depression vrith the plane of the deck. "When, therefore, the ship heels Y degrees, a weather-gun may be placed level with the horizon, and a lee-gun may be elevated 4 degrees Avith the ho- rizon, &G. It is only, however, in chasing and hard carrying, that ships heel so much, or more than 4 or 5 degrees. NOMENCLATURE AND PEOPORTIONS OP THE CAEEIAGE. The names of the parts of a carriage are, beginning with the lowest, the axletrees, arms of axletrees, fore and hind trucks (not forward and after, which is con- fusing), brackets, transom, breast-piece, bed, quoin, bed-bolt, transom-bolt, cap-square, joint-bolt, trunnion- holes, steps of the brackets, and side-tackle and train- tackle bolts. The arms of the axletrees are two calibres in length, and one in diameter. The trucks are a calibre in thickness; the fore- trucks when of oak are three calibres in diameter, the hind two and a half If the trucks were made smaller in proportion to the axletree, they would not turn easily, and perhaps not at all. On the other hand, if they were larger in proportion to the axletree, they would turn more easily, which would occasion the gun to recoil with 62 GUN CAKEIAGES. greater violence on tlie breeching. Tlie proportion here given is a compromise, an'ived at after long ex- perience, between mo\ing so hard as to occasion the gun to be got out with great difficulty, and moving so easy as to occasion the breechings to suffer.* The brackets are a calibre in thickness, and of a height corresponding with the height of the port from the deck. The transom is a calibre in thickness, and as broad as the sj^ace bet^veen the fore axletree and the gun Avill permit. The transom is indispensable, as adding greatly to the strength of a carriage. The breast-piece slides and spikes into a mortice in the brackets in front of the transom ; the height of its position in the carriage equals the height of the port- sill. The object of the breast-piece is not to give strength to the carriage, but to afford a point by which it may strike and rest firmly against the ship's side. Its width is such as to preserve the fore-trucks of the carriage at some distance from the water-ways when the gun is out to port, in order that in training, the trucks may not present an obstruction by taking soon against the water-ways. Formerly, when ships' sides tumbled home considerably more than now, all car- riages had but about 4 inches projection of the breast- piece beyond the ends of the brackets. But in wall- sided English and French ships, a breast-piece with nearly or quite 12 inches projection is used. In our own service, however, the 4-inch projection is retained, which interferes very much in the new wall-sided ships * More recently lignum vitse trucks are introduced. It is not easy to get wood thick enough, though, to make them larger than 15 inches. Hence all are uniformly of that size, fore and hind. These trucks neither rot nor shrink. They are thought to facilitate extreme training, because of their easier lateral slide. GUN CARRIAGES. 63 witli tlie ease and extent of training, and may there- fore in tliem be regarded as objectionable.* Standing in the middle of the present port, guns train nearl}' 25 degrees \vith the beam ; and when standing in one side of the port, they train more than ',)0 degrees before the muzzle " woods ;" and mth the long gun it is possible imder extreme ou'cumstances with great labor to attain 38 degrees. Incredible storli's are related of the time in which it is possible to discharge a gun trained at 38 degrees, reload, train it sharp the other ^vay, and fire. The bed and quoin are arranged to produce all the elevation and depression the port admits ; and to pre- \'ent the quoin receding under the shock of fire, it is furnished with an iron projection on the bottom, which catches in the holes of a rack secured to the bed. The bed is kept in its place by a hook which takes hold of the bed-bolt. The transom and bed-bolts hold the lirackets firmly in place ; the latter supports the fore end of the bed. The trunnion-holes, in which the trunnions rest, are cut Avith their centimes distant t-wo calibres fi-om the fore ends of the brackets. The cap-square joint-bolts, and the side-tackle bolts, pass \-erticnllv through the brackets and axletrees, and b}' being scre\\'ed up underneath the axletrees, secure them strongly to the brackets ; the screw and nut being preferable to the I'lvet, because, owing to shrinkage in the wood, carriages often neecl tightening up ; and for convenience of storage they are some- times put away in pieces. The " steps of the caiTiage'' are the oftsets in the brackets. By them the breech is pried up with hand- * This is the popularly-received view ; but in Pnrt II. it is contro- verted, which see for this, and more on graduating decks and training. 64 GUST CAREIAGES. spikes, in elevating or depressing. Dispensing with these "steps" is an error sometimes committed by those who attempt improvements. ANALYSIS OF THE CAEKIAGE. The four-truck gun-carriage in common use now on board ship, has continued in its present form and pro- portions, without material alteration, for nearly 300 years. It is, however, acknowledged to have great defects, which have caused many attempts to improve it. But no new carriage has yet recommended itself so far as to be adopted wholly as a substitute, though the Marsilly has in part. The good points about that old carriage which have caused it to be adhered to through so long time and so much service, are 1st, strength ; 2d, simplicity;* 3d, stability ; 4th, transportation from port to port, or from side to side, for use ; 5th, capability, in case of parting a breeching, of being brought up to port again for reeving a new one without difficulty or delay. These points are all absolutely indispensable. The objectionable features of the carriage are, 1st, it is, in recoil, under a gun, very hard on the breech- ing ; 2d, it requires great force to get it out to bat- tery, but if it be made to move out easier on the trucks, it will recoil more violently on the breeching, and vice versa, so that it is difficult to remedy one of these evils without increasing the other ; 3d, it gets out of the centre of the port, and in a sea way or * By simplicity of construction is meant the absence of any complica- tion which is liable to derangement, and which, if deranged, will produce disability, or which, in the hands of careless or unskilful people, or people excited in the heat of action, could, by mismanagement or forgetfulness, produce disaster. GUN CAKEIAGES. 65 under mucli heel of the ship, is with difficulty and delay brought back to its proper central position again ; 4th, it trains slowly and unsteadily, through a limited sweep, and cannot be fired instantly when the sight is on with the object of aim, but notice must be given, and a moment's delay experienced, for the crew to get clear of recoil, in which moment the ranging, yawing, or rolling of the ship, may throw the sight off the object; 5th, when the ship has much heel, it is difficult to take in the slack of the train-tackle, as the lee-gun recoils, fast enough to catch and hold it in sufficiently far for loading, in which case the delay and labor of getting it in is considerable ; 6th, the manage- ment of the side-tackles of weather-guns, under great heel, or in a sea way, is an objectionable difficulty ; 'Tth, when trained it recoils with an unequal strain upon the two legs of the breeching and their bolts ; and 8th, when a lee-gun runs out violently, the effect is to open the water-way seams, and start the shot from its seat. The spread of the trucks gives more stability than is required against the pitching motion of a ship when the gun stands in its port, yet not more than is re- quired under the rolling motion when the gun is se- cured fore and aft, or under transportation. But there is a lack of stability under roll of the ship, which comes from the proximity of the two vertical planes, those of the fore axletree and of the centre of gravity of the gun and carriage, which centre of gravity is about an inch back of the trunnion-holes. An examination of the various inventions proposed in England, France, and the United States for mount- ing ships' broadside guns, will disclose the fact, that in every endeavor to remedy the defects of the old car- riage, a sacrifice has been made of some one or more 66 GEAR. of its five good and indispensable points enumerated in tlie foregoing analysis. But wlienever a carriage is produced whicli roitigates or avoids the objection- able features specified, witliout any sacrifice of the good points, it ought, and it is reasonable to suppose in time will supersede the one now in use. The Marsilly carriage eases the recoil, but at the expense of the decks. It runs out easily by aid of the roller-handspike when it is used. By not using it with a ^ee-gun, the shock against the ship's side is re- lieved. It is a decided improvement. GEAR TO CARRIAGES AND GUNS. Of this not much need be said. Carriages require tackles to govern all the motions to which they are liable, or which it may be desired to give them. The side-tackles, by being hooked to bolts midway be- tween the ports in the ship's side, perform the offices both of running out and training. They govern the fore and aft motion, and one of the thwart-ship mo- tions. The other thwart-ship motion is governed by the train-tackle. It may be remarked, that the falls and blocks of all these tackles should be kept pliable, and free from friction. A stout serviceable breeching is all-important. It is usual to cast on the cascable of guns now, instead of the neck and knob, a " shark's mouth," in which to snatch a breeching ; and in the carriage's side, there is a, crotch instead of a ring-bolt to receive the breeching Also in the ship's side there are shackle instead of ring-bolts. By means of these new arrangements, a breeching when shifted has not to be unclinched and unrove as formerly was the case, but is unshackled at GUNPOWDEE. 67 the ends and taken out of the crotclies and shark's mouth, and replaced by another breeching, in some seconds of time. It is said, that one part of a gun's crew can shift a breeching whilst the other part is loading the gun. This is a matter of most serious consequence, and one very much attended to by those nations with whom we are likely to come in col- lision. In respect to these arrangements, it is right to say, that they require extraordinary attention to prevent the shackle and other pins becoming rusted in place, as they will do unless all of them, including the linch- pins, are moved every day, and cleaned often. SECTION V. GTTNPOWDEE, ITS FABEICATION, AND THE THEOET OF ITS EXPLOSION. — PEOPOETIOXING CHAEGES OF POWDEE FOE GUNS OF DIFFEEENT WEIGHTS, AS COMPARED WITn TIIEIE SHOT. — CHAEGE FOE DOtTELE- 8H0TTED LONG GUNS, AND FOE THE 8-INOH PAIXHAN. ^FLANNEL OTLINDEES. FILLING POWDER.— EEDUCED CHAEGES. GtlNTOWDEE. GtTNPOWDEE is composed of three substances : nitre (saltpetre), carbon (as wood charcoal), and sulphur. These substances, when well mixed by mechanical means, form a compound which is both explosive and propelling. There are substances, such as the fulminate of mercury, commonly called detonating powder, which are explosive in a much higher degree than gunpow- der, and yet are much less propelling. The theory of explosion is, that the explosive substance changes its form under ignition from the solid to the gaseous ; in 5 68 GUNPOWDER. wHcL. latter state it occupies a space many thousand times greater tliau when solid. This change of form, in fulminating or detonating powder, is more rapid and 8udden than it is in gunpowder ; but the gas formed does not expand through so large a space. In the bore of a shotted gun, fulminating powders expand rapidly and violently, and also through space enough to burst the gun, or indent the l:)oro, or break the shot ; but not through space enough to give high ve- locity to a ball. This has been proved by experiments made at Woolwich.^ — (^See note^ p. 127.) With gunpowder when firmed, the change from the solid to the fluid form, although instantaneous, is not simultaneous. The particles ignite in a succession which is almost inconceivably rapid ; but the whole charge in a gun is not burned until the shot has nearly or quite reached the muzzle. Consequently, the whole force of explosion is not concentrated on one portion of the bore, but is divided throughout its whole length, and the ball is propelled along it with a ve- locity which is constantly accelerating, and which reaches its highest point at or near the muzzle. The proportion of the ingredients found by experi- ment to make the best gunpowder, is 75 parts in weight of nitre, 15 of carbon, and 10 of sulphur. Nitre and carbon are the essential ingredients to pro- duce explosion ; sulphur is added to facilitate ignition and give firmness and consistency to the grains, which otherwise would crumble by handling or by transpor- tation. ^ These materials are separately purified by removing the foreign substances which they may contain. For example, the saltpetre of commerce holds mixed with it, common salt, lime, magnesia, and other minerals which absorb moisture, and by their presence add to eU^TOWDEE. 69 tlie weight and decrease tlie strength of powder. Pure nitre does not absorb moisture. That ingredient should, therefore, be rendered entirely pure, because moisture occasions the powder to cake, and destroys its ser\'ice strength. All powder does cake, however, from moisture, not- withstanding the purity of the nitre it may contain, and charcoal is then the ingredient which, owing to its po- rousness, and its consequent avidity as an absorbent, takes up and holds this moisture. But that coal which is made from the lighter and firmer woods, as dogwood and willow, is least porous, and is therefore preferred for the manufacture of gunpowder. If properly manufactured with pure nitre, and with charcoal prepared from the selected woods, and not exceeding in quantity the established proportions, powder is capable of absorbing but one per cent, of its weight of water. But if the carbon exceed the es- tablished allowance by more than 3 or 4 per cent., the moisture which the powder can absorb perceptibly in- creases, with a consequent increase of the evils arising from absorption. The plain distinction between the two substances, charcoal and nitre, in their relations to moisture and dampness, may be thus stated : Charcoal absorbs even moisture, and gives it off again with great facility; is alternately moist, or wet, and dry without melting or dissolving, in which respect it resembles sponge ; but, unlike the sponge, under moisture it becomes in some degree adhesive, sticky, which causes it to dry caked in lumps, something as clay does. Mtre, though «ot susceptible to mere moisture in the air, therefore not strictly deliquescent, will yet dissolve under damp- ness, and separate from the charcoal with which it is mechanically united in the gunpowder. So it may. 70 GUJJPOWBEK. by leecliing or lixiviation, be wholly washed from the mass of powder. Charcoal for powder, if not sxifficiently burned, does not ignite quickly ; or if burned too much, it becomes hard and resists rapid ignition. It is important, there- fore, that coal for this j)urpose should be thoroughly and yet not too much burned. In fal)ricating gunpowder, the materials are stirred together dry in tubs. The mixture is then wetted slightly, and placed in masses of 40 or 50 pounds at a time, on stone slabs under cylinders of stone weighing several tons, and rolled (the process of stirring and mixing still going on), until the even and close me- chanical incorporation of the parts is regarded as com- plete. This done, the gunpowder is essentially made ; and in this state is termed mill-cake pmoder. When new, and dried by artificial means, mill-cake powder is strong ; but it will in that state rapidly absorb moisture from the natural atmosphere, and as rapidly deteriorate. To prevent this, the powder is pressed, granulated, and glazed. Pressing it, by increasing its density, decreases its porousness and consequent power of absorption; granulating, breaks it into particles to facilitate ignition; and glazing, is an additional guard against the absorption of moisture. When the powder has been thus pressed under several tons weight, and its density or specific gravity increased to the desired extent, it is termed ^re"tional windage of ^V the dia'meter of the hore. Now, and since 1840, new shot for the navy have a 6 84 WINDAGE OF SHOT. fixed windage of from yV to f^ of an inch, for all calibres. Shot are cast with, less diameter than tLe bores they are intended for : 1st, to allow for want of sphe- ricity ; 2d, to allow for the formation of rust on the shot and in the bore ; and 3d, to allow for the expan- sion of shot, which at a white heat is -^l. the diameter. With the reduced windage of yV of an inch, shot of a higher calibre than ■42-pdrs., mil not, when at a white heat, enter the bore. Thus, the highest diame- ter of a 42-pound ball when cool is 6.90 inches, and when at a white heat, 6.998. The diameter of a 42- pdr. bore is 7.018 inches. Consequently, a 42-pdr. hot shot has only .02-inch windage. The shot of an 8-inch gun is, when cool, 7.90 inches diameter ; at a white heat it is 8.013 inches diameter, or .013 greater than the diameter of its bore. The figure represents a shot in the bore of a gun, and the crescent-shaped space between the two circles indicates the windage-ring, as that space in a gun is termed. If this ring l^e large, much of the force of the inflamed j)ow- der will escape past the ball and be of no service. To avoid this escape is one of the advantages of reduced wind- age. The area of the wind- age-ring, is determined b}' sub- tracting the area of the shot's section from the area of the section of the bore. Simmonds says, " It is quite clear, whether wind- age be regulated in proportion to the diameter of the shot, or at a fixed limit, that the windage or space by which the elastic fluid escapes, will be greater as the WESTDAGE OF SHOT. 85 calibre increases ;" and " A larger gun, wlien alike charged, will discharge its sliot witli less velocity than the smaller gun ; its regulated charge is alike, but its efficient charge is less." The windage-ring is greater as the calibre increases, but is not greater in proportion to the charge of pow- der. To show this, take for example two bores, the 42-pdr. which for convenience suppose to have a diam- eter of 7 inches, and an 18-pdr. with a diameter of 5 inches. Suppose their shot to be respectively 6 inches and 4 inches diameter, having each a fixed windage of one inch. Deducting areas of the sections, the windage-ring of the 42-pdr. •\^-ill be 10.21 square inches, and the windage-ring of the 18-pdr. will be 7.07 square inches, or nearly in the proportion of the diam- eters of the two bores.* But the weights of the shot, and consequently their charges of powder, are as the * The precise relation of windage to bore worked out mathematically by Professor Chauvenet, is as follows : Put the diameter of bore = D, and the diameter of ball = d, and the windage which is supposed the same for all calibres = W = D — d. Then the area (A) of the windage-ring is expressed by A = (D^ — (1=) X .7854 = (D + d) (D — d) X .7854 or A = (D -f d) W X .7854 (1) Tn this expression, the only variable quantity is D + d. Hence, the windage being constant, (lie area of the windage-ring is proportional to the sum of the diameters of the bore and the ball, or nearly proportional to the diameter of the bore. If D', d', A', represent the diameter of the bore, &c., of another gun, we have, in the same manner, A' = (D' + d') W X .7854. (2) The difference between (1) and (2), gives for the increase of the wind- age-ring, A' — A = CD' — D + d'— d) W X .7854. ' But since the windage is constant D' — d' = W = D — d, by trans- position D' — D — d' — d, and consequently D' — D -)- d' — d = 2 (D' — D) ; hence, A' — A = 3 (D' — D) W X .7854, in which the only variable quantity is D' — D, the increase in diameter of the bore. Hence, the windage being constant, the increase in the a/rea 86 WINDAGE OF SHOT. cubes of tlie diameters; hence the proportion of the charge which escapes in tlie windage-ring is onuch less in large than in small calibres ; the reverse of wliat Simmonds states, and the reverse of opinions generally entertained. Besides the escape and loss of fluid through the windage-ring, another and greater disadvantage arising from large windage is, that it occasions inaccuracy in the flight of shot; for, instead of moving along the bore in a line parallel with its axis, and leaving the gun in the same line produced which is the direction of aim, the shot, if it have great windage, will deflect from the bottom to the top of the bore as in the fig- ure, or from side to side (termed balloting), and may leave the muzzle with a direction upwards, or down- of tlie windage-ring is proportional to the increase in the diameter of the iore. Hence again, A_2'W B D ' A and the fraction ~- represents the proportion of the charge which es- 2 W capes hy the windage-ring, and the equivalent fraction varies in- versely as D. Tlierefore, the fraction expressing the portion of the charge which escapes throvgh the windage-ring varies inversely as the diameter of the tore ; which justifies the conclusion of the author stated in the text. Thus, if \ of the charge is lost in a 5-inch gun, only Jj- is lost in the 10-inch gun, and consequently, when the regulated charge is alike, the efficient charge of the large gun is greater than that of the small gun. ECCENTKICITy OF SHOT. 87 wards, or lateral, which is altogether uncertain, de- pending upon the point iu the muzzle on which the shot last impinged, and therefore necessarily interferes very much with the accui-acy of firing. Shot of large windage, owing to their greater dis- position to deflect, and the greater force with which they are deflected, indent the bores of guns much more than shot of small windage ; and are always pro- jected with much less accuracy. A gun loaded with a shot of the least admissible windage on the one hand, or with an excessively large windage on the other, is less strained than it is by a shot of only moderately large windage. Thus the small windage of y'^- of an inch gives less strain than -i\, for although the latter permits greatest escape of fluid, it acts, in escaping over the ball, something as a powerful wedge between tops of the bore and shot, to force down the latter upon the gun. Accordingly, shot with a windage of about y\ are always found to indent the bores most at the seat of the shot, which indentation is the measure of strain to which the gun has at that part been subjected. With either less or more ^vindage than -^-^, the evidence of strain becomes less, and the balls ballot less. On this principle, it is supposed that rifled-cannon are least strained by their tight-fitting shot, wholly without wedge as they are, and causing therefore no indentations in the bore, or other signs of damage. Hence a rifle-cannon charge of powder may, it is thought, safely be in excess of the proportions for smooth bores. EccENTEiorrr of shot. In casting shot, short weight often arises from large cavities, formed within the sphere by confined 88 CAUSES OF DEVIATION. air. These cavities also cause shot to have eccentricity^ or deviation of the centre of gravity from the centre of the balL Thus, in the figure which is the supposed section of a shot, if c be the centre, and d d be cavities in the casting, the centre of gravity will be at some point e, on one side of the centre c. Eccentricity of shot, whatever the cause, is of very general occurrence ; so much so that nearly every shot that is met with has what is termed preponderance ; that is, one particular section of it will be found to preponder- ate over every other section, if the shot itself be floated in a bucket of quicksilver. If no preponderance be detected by this simple and accurate mode of balancing a shot, no appreciable eccentricity can exist ; on the contrary, the shot is then considered as concentric. The degree of promptness, the com- parative quickness of motion, with which an eccentric shot, floated as above, assumes the position due to its preponderance, is regarded as the relative measure of that preponderance. If it assume that position with a certain degree of celerity, its eccentricity ov prepon- derance must necessarily be considerable; otherwise inconsiderable. EFFECTS OF EOUGHlSrESS OF SUEFACE AND ECCENTEICITT ON THE ACCURACY OF A SHOt's FLIGHT. Interesting experiments with targets and screens, show, that generally, shot deviate in a curve, both to the right and to the left of the direction of aim, even in the course of the same flight, which accounts for in- CAUSES OF DEVIATION. 89 accuracy of firing, even where aim is careful and delib- erate, and wiien other circumstances are favorable to accuracy. A satisfactory explanation of tlie causes wHcli operate to produce these deviations, is as follows : Suppose h in the figure, a cannon-ball, projected with high velocity fi'om r towards o. Suppose the ball, on leaving the muzzle, to have impinged upon the left side and taken up a rotary motion ffom right to left on the axis ^ ia a vertical plane. The deflection of the ball from the left side of the muzzle will cause it to deviate at first to the right towards d; and that deviation will be increased by the friction of the atmosphere upon the surface of the ball. The rougher the surface, the greater will be the friction and consequent deviation arising from friction. Thus, to suppose an extreme case of friction, let it be such as would be produced by projections on the sur- face of the ball like paddles, at p and , exceeds in velocity the left side which has a motion of rotation in opposi- tion to that of the shot's progression. The left side, having least velocity, meets also least resistance ; and consequently the shot, inclining in the direction of least resistance, tends in its flight to the left, as towards «, and deviates on that side of the line of aim. If the ball, on leaving the muzzle, impinges on the CAUSES OF DEVIATION. 91 opposite side, taMng up a rotation from left to right, tlie curve will be tte reverse of that described : and if the shot be eccentric, both these causes of deviation will greatly increase ; for, the centre of gravity is the centre of motion, and the more on one side of a shot that centre is, the more unequal -will be the velocities, and consequent resistances, on the opposite surfaces. The greater the windage of shot, the greater the deflection and revolution to which the shot is liable, and consequently the greater the deviations produced by these causes. Again, if the axis of rotation, produced by the ball's rolling along the bottom of the bore and imping- ing last upon the bottom of the muzzle, be horizontal and at right angles with the line of flight, the effects will be as follows : Suppose i a ball projected towards c, and leaving the muzzle of the gun as just stated with a revolution on the horizontal axis h I, which is at right angles with the line of flight. If the ball be perfectly concentric, it will have no deviation. But if the side h be hea^d- est, the side I will take highest initial velocity, and in- cline the ball to the right in the first part of its flight. But h will hold highest remaining velocity, inclining the ball in the latter part of its flight to the left, and occasion it to strike to the left of the object of aim c. The reasoning in this case may not be so conclusive as 92 CAUSES Oi' DEVIATION. that in tlie one preceding, and tlie deviation would seem in some measure to depend on the superior den- sity of the ail' beneath the shot, produced by its falling motion. As it is impossible to know on which axis the ball will revolve, or how it may be deflected from the muz- zle, no allowance in aim for deviations can be made, but sight must be taken directly at the object. In cases where the wind blows across the line of fire, some allowance in pointing may be made for its effects. When the axis of revolution makes no angle with the line of flight, but coincides with it as in a rifle-ball, there is no deviation except that which may arise from the superior density of air beneath a falling body. The coincidence of tlie axis with the flight, rarely happens with shot thrown from a cannon, or from any other smooth-bored fire-arm, but is produced al- ways by the rifle-bore, and is the cause of the noted accuracy of rifle-shooting. From the foregoing considerations it follows, that the smoother the surfaces of balls, and the less their windage and eccentricity, other things being equal, the greater their accui'acy. And when desiring to fire with unusual deliberation and accuracy, it is proj^er to select shot of least windage, least eccentrieit}', and smoothest surface ; and experiments made in Europe show that the preponderating or heaviest side of the shot (if it be known) should be put next to the charge. It follows also, that when a ball is deflected from the line of aim by a blow on one side at the muzzle, the less the charge of powder, the greater will be the resultant angle of deviation produced by the blow ; and, that since the deviations produced hj fi-iction of the atmosphere are in proportion to the times in which that friction operates, the ball which accomplishes a INSPECTION OF SHOT. 93 certain range in a given time has but half the angle of deviation that another ball will have if accomplish- ing the same space in double the time. Hence, high charges, and high velocities, are essential to accuracy, especially in distant firing; and this constitutes the chief advantage of long guns, which bear, and burn, heavier charges ; and accounts for the greater accuracy of larger and denser balls, which, besides being less readily influenced by the deviating causes, retain their velocities longer, and consequently accomplish their distances in less spaces of time. INSPECTION OF SHOT. Shot, says the " Ordnance Manual," should be in- spected 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 the metal is sound, and free from seams, flaws, and blis- ters. If cavities or small holes appear on the surface, strike the point of the hammer into them, and ascer- tain their depth with the searcher. If the depth of cavity exceed 0.2 inch, the shot is rejected; and also if it appear that an attempt has been made to conceal such defects by filling up the holes with nails, ce- ment, &c. The shot must pass in eveiy direction thi'ough the large gauge-ring, which is -^-^ of an inch smaller than the bore, but must not pass through the small gauge- ring, which is -\ of an inch smaller than the bore. Shot are then rolled through the cylinder-guage, which is a cast-iron cylinder, of a diameter equal to that of the large gauge-ring, and 5 calibres long. This is set at an inclination of about two inches between the two ends, and supported on blocks of wood in such a 94 PBESEEVATION OF SHOT. manner as to he easily turned from time to time, to prevent its being worn in furrows. The last proof of shot is to drop them from a height of 20 feet on a Hock of iron, or roll them down an inclined plane of that height against other shot at the bottom of the plane. This tests tenacity. The average weight of shot, is deduced from that of three parcels of 30 or 60 each, taken indiscriminately from a pile. Some of those which appear to be the smallest may be separately weighed, and they are re- jected if they fall short more than one thirty-second part, of the weight expressed by their calibres. Shot almost invariably exceed that weight. PKESEKVATION OF SHOT. Balls should be carefully lacquered soon after they are received from the foundry. When relacquered, if old shot which have before been in hand, scrape off the old lacquer, but the balls should not be heated to do this, says the " Ordnance Manual." Pile the balls, under cover if possible, or where there is a free circulation of air. And pile upon a hard-made dry foundation, which is best if made from unserviceable shot. It is in shot-lockers, however, at sea, that shot are most injured by rust, because the moisture which con- denses on the shot, the sweat as it is called, cannot there dry off as it does when they are on racks placed in positions subject to circulation of air. A method of protecting shot formerly in favor was to coat them very thinly with zinc. The action of iron and zinc was thought to be galvanic, and change the pole of the iron. It is very doubtful, however, if the effect was any thing else than a covering of zinc, which WADS. 95 had &st to be eaten tlirougli by oxidation before access was obtained to the iron. The practice is dis- continued. Whilst the rust is upon the shot its size is in- creased ; but when the rust is removed the shot be- comes reduced in size ; its windage is consequently increased, and its surface is rendered extremely rovigh — both of which cause, as has been shown, great loss of accuracy. Whilst shot had an original windage of ^V the hore^ increased by rust scaled off in many cases to nearly half an inch, there was never danger of such an accumulation of rust as would cause them to jam in the bores of guns. So far then as apprehension from that source was concerned, they might be neglected with impunity. But with shot cast having only 0.1- inch windage, if neglected as formerly the accumula- tion of rust mil render their entrance in the bore ex- ceedingly uncertain. Hence the absolute necessity on board ship of putting shot in dry lockers or racks, and inspecting and cleaning them often. Beside, the new shot are adapted to produce great accuracy both on account of their small windage and smoothness; and these advantages ought not to be sacrificed by neglect and carelessness, and need not be, if a tithe of the pains sometimes thrown away on bright work be de- voted to the shot. WADS. There are two kinds of wads in common use : the junk-wad, and the grommet-wad. The junk-wad is made from junk, driven hard, by blows with a mall, in a wooden cylinder of the proper diameter prepared for that purpose. Hard as the junk-wad is, it may be compressed, under ordinary 96 WADS. screw-power in an iron C34inder. hy the force of one man, into oue-lialf the thickness it is formed to under the malL These -wads are hard enough for small-cali- hred guns ; but if for very heavy shot, and to be used Ijehind the shot, it is suggested that they should be made harder by applying screw-pressure in their prep- aration. A Avad intended simply to put over a shot and keep it in place, had perhaps better be soft. The rope-grommet or the selvagee-wad cut, is in- tended only to be put over shot ; and is said to pro- mote accuracy by preventing deflections of the shot in the bore. When rammed home, it almost invaria- bly takes its proper position around the shot, trans- verse!}- with the bore, however carelessly thrown into the bore. The grommet-wads or the selvagees may be always kept at the guns, and consequently always at hand when clearing for action. They do not rot, nor swell so as not to enter the bore, as happens with junk- wads Avhen kept at the guns and frequently wet. An ad- vantage in action which the grommet have over the junk-wads, is, that they neither form a pile for pow- der-boys to stumble over if put in rear of the battery ; nor if j)ut next the shij^'s side will they scatter and kill people when struck hj an enemy's shot, as cer- tainly must be the case with cheeses or nets of hard wads ex]3osed between the guns' ci-ew and an enemy. The formation, selection, adaptation to peculiar uses, and care of wads, is a subject worthy of more thought and attention than is usually conceded. A wad between the 230w HELLS. IMPLEMEJSrrS. Tlie implements used in serving guns are tLe ram- mer, the sponge, tlie worm, the ladle, boring-bit and priming-wire. The rammer-head is made from ash, beech, maple or other tough wood. In diameter, it is -J- less than the bore, to admit of easy entrance, and allow for swelling when wet. Its length is equal to the diam- eter of bore. The staff is regulated in length by the length of bore. For chambered guns, the rammer is tapered a little at the extremity, so that even a re- duced charge may be assuredly rammed home. The wooden sponge-head is of elm or ash, one inch smaller than the calilire, and commonly eight inches long. For a chambered gun, however, the sponge- head must evidently be made of an additional length ; and of a shape adapted to the slope and chamber, as well as to the cylinder of the bore. The wooden sponge-heads were sometimes covered with lamb-skins, dressed in alum, with the wool on. Now, by regulation, in making new sponges a fabric is substituted for the lamb-skin covers. Sometimes with canvas, having -R'oollen yarn thrumbs woven in full and thick, Avhich, trimmed down, makes a sponge said to wear longer than the lamb-skin and not to in- 98 LOADING GUNS. jure so much from dampness or moth. Sometimes again it is a brush. Sponges in the naval service all have a worm in the extremity, the object of which is to take out frag- ments of the burned cylinder that may be left and ac- cumulate in the bottom of the bore after several dis- charges. Army sponges are not so made. When the sponges are not fitted with worms attached, the sepa- rate worm must be entered after a few discharges. The ladle is of copper. Its use is to extract the shot ; also to remove loose powder scattered from a torn cylinder. Priming-wires are of iron, hardened so as not to bend too easily, and yet not so much hardened as to become brittle and readily break. Boring-bits are tempered to a still higher degree. But if they are too hard, they are liable to break off in the vent, and no drill can cut them out. This has been known to occur, and to render a gun unservice- able for some months. On the other hand, if a boring- bit is too soft it will not effect the purpose for which it is intended, that of removing obstructions from the vent. It is better to err on the safe side, and have a boring-bit too soft than too hard. LOADING GUNS, SPONGING, AND ATTENDING VENT. A gun having been dischai-ged, the first operation in reloading, is to " stop vent and sponge." The object of sponging is threefold : 1st, to remove any fragments of cylinders that may remain in the bore ; 2d, to extinguish any remaining fire ; and 3d, to clean the bore and prevent too great an accumulation of paste. The first object is attained by pushing the sponge LOADING GUNS. 99 ao-ainst the bottom of the bore, and turning it from left to right through at least one entire revolution ; the second is produced by stopping the vent, and briskly drawing the sponge, which operation exhausts the air and extinguishes fire, drawing also the remain- ing fragments ; and the third is effected in the process of accomplishing the other two. In the operation of sponging, there are two ques- tions, concerning which artillerists differ. One is, shall the vent be closed on entering the sponge as well as on drawing it ? The other is, shall the sponge be wet, either for the extinguishment of fire, or for cooling the gun ? In relation to the first question, the arguments jyro and con are briefly these : If the vent be open whilst entering the sponge, a current of air is produced through the vent-hole, which current may fan up any spark of fire remaining in the gun, and drive fragments into the vent. This last has occuri'ed, from the cause men- tioned, or from some other, and prevented the entrance of the priming- wire. On the other hand it is argued, that if the vent be stopped whilst entering the sponge, the air, having no escape except Avith diflaculty past the sponge, becomes compressed ; which compression promotes combustion, upon the same principle that exhaustion checks or destroys it. Il^aval authorities usually are found to favor closing the vent from the commencement of the operation of sponging. This corresponds with the usual proper order, " stop vent and sponge." The sentiment amongst the scientific gentlemen of the army ordnance corps, seems to be the reverse, and favorable to leaving the vent open. In regard to the second question, the Ordnance 7 100 LOADING GTJNS. Board in an official paper unhesitatingly condemns the practice of wetting the sponge, because its eflect is to make a paste of powder in the gun, Avhich paste, burn- ing like a squib, is liable to hold fire beyond the power of the sponge to extinguish. In some English books, occasionally wetting the sponge is recommended as an expedient to cool the gun. A moist sponge is favored by the new naval ordnance I'egulations. LOADING WITH CAETEIDGE, AND BAMMING HOME. When the gun has been well sponged, put in the cartridge to the muzzle, with seam down, or on the sides, and tie out ; so as to avoid pricking, or having to ignite, throu2:h more than one thickness of flannel. Enter the rammer upon the cartridge, and push — not drive — it nearly to the bottom of the bore ; then give two or three smart successive blows to insure its being sent home. There is not unfrequently, even with careful officers, and otherwise well-trained crews, a want of attention in this matter ; for the rammer- ]nan often gives the cartridge a blow with the rammer- head when just within the muzzle, Avhich stretches the ilannel, increases the diameter of the cylinder, and causes it to tighten very much in the bore. Then, it can be got home only by blows, which may probably burst the cylinder and spill the powder along the bore. The cartridge is judged to be home, by feeling it through the vent Avith the priming-wire. If the cartridge be not sent entirely home, the priming-tulje or percussion-wafer may fail to ignite it, and consequently, by missing fire, time must be lost, and possibly a most decisive shot. But if a charge not rammed home does ignite, a still worse consequence may follow, namely, explosion LOADING GUJSrS. 101 of the gun. A vacant space exists wHcli the fluid must occupy before it can act to propel the ball: hence the fluid begins to act upon the ball with an ac- cumulated force, and the result is similar to that which follows the use of fulminating powder (see page 68). The same must evidently occur if the shot is not home, a vacant space existing between the powder and shot. Heavy bodies, from a state of rest, reach high ve- locities through successive increments of motion, al- though those increments may be rapid, and take place in portions of time almost inconceivably small. The greater the force applied, or the more sudden, or con- centrated, or accumulated, its action, the more rapid must be the increments produced, and the greater the strength of parts necessary to resist the corresponding reaction. A familiar illustration of this principle is seen in the effort often made to start a heavily-laden wagon by the sudden movement of a poweiful team ; the result of which is rupture to the harness or other gear, unless it be of great strength. But if this same force be applied to produce motion through more gradual increments, the highest velocity may be ob- tained without strain or signs of violence. So also, if a shot in a gun be moved from a state of rest to one of high ^'eloeity, through comparatively moderate increments of motion, the same law holds, and no injury is experienced. But if the shot be moved by a force so preat, or so accumulated, or act- ing so suddenly, as to produce more rapid increments, the reaction upon the gun ^^■^\\ be proportionally great or sudden, and endanger its explosion. Dr. Hutton, Braddock, and others attest, that a whole charge of powder in a gun does not burn simul- taneously, as is proved by the fact that many grains are often blown from the muzzle unburnt. It is prob- 102 LOADING GUNS. able the ignition is successive ; the charge exploding as it were portion by portion, until the whole becomes inflamed. When the space in a gun below the ball is entirely fiUed with powder, the first portion that burns acts upon the shot and starts it from its seat ; the second portion gives an additional increment ; the third portion still another increment, and so on ; each successive portion communicating accelerated velocity until the shot reaches the muzzle of the gun ; by which time all or nearly all the powder is burned, and the highest velocity due to the charge has been commu- nicated to the ball, through increments so gradual as to produce no appreciable strain, or at any rate signs of violence. If, however, the shot or the charge should not be rammed entirely home, and several inches of vacant space should be left below the shot, a considerable portion of the charge will have been burned before the fluid has filled the space sufficiently to move the shot. Hence the shot, instead of being moved by the com- paratively gentle force of successively igniting por- tions, will ])e overtaken, in a state of complete rest, by the accumulated force of several portions ; and as it cannot, under these circumstances, yield rapidly enough to the accumulated force of the immensely expansive fluid, it of necessity makes a vent for itself by tearing asunder the gun. THE USE or WADS IN SHOTTED GUNS. From what precedes, it is manifest that all vacant space below the shot should be prevented by ramming it and the charge close home. This is indicated by the jar given to the prindng-wire when inserted in the DOUBLE-SHOTTING. 103 charge, and the charge or shot receives a blow from the rammer. When guns are loaded to remain so while cniising at sea, it is usual to put a hard wad between the shot and the charge. But in action, it takes time, is of no service, and is therefore not practised. It is possible that a soft wad, or one not very hard, placed in rear of a large shot, by being subject to compression under the action of the charge and re- sistance of the shot before the latter has taken up any motion, is, to the extent of that compression, equiva- lent to a vacant space, and so far dangerous to the gun. A wad, either of hard junk, or of the grommet form, is put over a shot to keej) it in place under the motion of a vessel. Manifestly if the shot were liable to roll away from the charge, the gun would be endan- gered, precisely as if the shot were not originally rammed home. DOUBLE-SHOTTESTG. When it is intended to double-shot a gun, it should be loaded with a reduced charge. Guns are forbidden to be double-shotted without express orders from the quarter-deck. There is high authority for the practice of putting a wad between the two shot, which it is thought prevents their striking and breaking. Al- though this is undoubtedly correct reasoning in respect to smaller shot, it may be questioned Avhether a wad between the heaviest descriptions of shot, may not, to the extent of compression to which the wad is liable from the great force applied and resistance opposed, operate as a vacant space, and thus peiTuit the rear shot to take up motion, and strike the other in a state 104 BOUND AND GKAPE. of rest, whicli, reacting, may cause the gun to burst ; whereas, if the two shot were placed together, they might move off together as one. The Ordnance Regulations, ]d. 50, forbid a wad be- tween two shot or over grape. Two shot may be used at considerable distances against boats or troops uncovered ; but they have no accm-acy, nor penetration enough to pass through a heavy ship's side beyond 300 or 400 yards ; and not even at that distance, unless the shot are as heavy as 32-pdrs., and fired from long guns. EOUND AND GEAPB, In loading with round-shot and grape, it appears at first sight most natural to put the round in first, and grape last. Ordnance regulations discourage, with- out forbidding the use of round and grape together in the same charge. In respect to the use of grape, the books afford little information. It is known, however, that several of our older captains, from experience in the last war, consider grape as next to useless except against boats or to sweep exposed decks. PENETEATION OF SHOT. The comparative penetration of heavy and light shot, when fired with different proportional charges, may be illustrated by stating the results of practice with 18 and 32-pdr. balls. The penetration of inter- mediate calibres, is easily deduced from these data, aided by the table of penetrations appended. A 32-pdr. shot, to penetrate 30 inches of oak, equal to the thickness of a seventy-four's side, requires a re- PEITETKATION OF SHOT. 105 maining velocity of 1,090 feet per second. TMs ve- locity it will have, if fired with a charge of •i- at 1,000 yards distant, i 850 " i 500 " To penetrate a frigate's side, which is estimated to be 20 inches thick, a 32-pdr. ball must have a striking velocity of 850 feet per second; which velocity the shot will have, if projected with a charge of |-, at the distance of 1,200 yards. An 18-pdr. shot, to penetrate a seventy-four's side requires a remaining velocity of 1,200 feet. This ve- locity the shot will have, if fired with a charge of ■L at 600 yards. i " 450 " i " 400 " Against frigates' sides, an 18-pound ball to pene- trate requires a remaining velocity of about 900 feet. And this it will have with a charge of -i- at 900 yards i " 850 " ■1- " 800 " Knowing, therefore, the gun's calibre, and the charge of powder it can bear, it is easy to know also the extreme distance at which either a seventy-four or frigate can be sunk, if at all. PEISTETEATIONS OF SHOT FROM OAEEONADES. The striking velocity of a 3 2 -pound shot necessary to penetrate a seventy-four's side being 1,090 feet, and that necessary against a frigate's side being 850 feet, and the initial velocity of a ball from a carronade 106 DAMAGED POWDER. never exceeding 850 feet,* it would appear to follow, that a shot from a carronade of the 32-pdr. calibre can never penetrate a seventy-four's side, nor a frigate's side at any considerable distance. All caiTonades of calibres below 32-pdrs., it would appear, must certainly want penetrating force. These facts, in relation to penetration, are drawn from authorities. The infer- ences are volunteered ; but are apparently inevitable from the facts. The published practice tables still remain much more full and satisfactory in respect to ranges than penetration. Indeed, if the new Ordnance Regulations contain any information whatever on the subject, it has escaped notice.f FIEESTG WITH DAMAGED POWDEE. Owing DO damaged powder, which arose chiefly from exposure in damp magazines, in many of the actions of the last war shot had not the penetration due to their weight and charges as stated above, and consequently did not penetrate, but stuck in the sides of opposing vessels. This was the case in the action between Sir James Yeo and Commodore Chauncey, in which British shot did not penetrate ; between the Chesapeake and Shannon, in which the shot of both did not penetrate ; and in the action where the Argus * See rule, page 78, for calculating velocities of shot due to given charges of powder, -which, for the carronade in question, was ~ the / 3 P weight of ball, or 2.66 lbs. By the formula, V = 1,600 V — =800 feet per second. t The author begs indulgence to expi-ess a sentiment common in the service, viz., that on this and many such subjects it is now in the dark about, it needs light. And further, that to bury in mysterious archives other valuable kindred data obtained at great expense, is more monkisi and mediseval, than in accordance with the spirit and usual practice of the " nineteenth century," especially the latter part of it ' EANG-ES OF GUNS. 107 was lost, Ler sliot not penetrating. Ttese facts are mentioned with a view to impress tlie necessity of carefully preserving powder dry. To effect this, maga- zines are now provided with copper tanks in which the powder is carried. RANGES OF GUNS OF DIFFEEENT CAXLBBE AND WEIGHT, AT POINT-BLANC, AND AT DIFFERENT ANGLES OF ELEVATION. There is no term in gunnery so variously under- stood as that oi point-hlanc. Its true definition, as used hy the Americans and English is, that j)oint at which a shot, fired from a level gun loaded with its full service charge, crosses in its flight the horizontal plane on which the trucks of the gun stand. The dis- tance of that point from a gun, is the " point-blanc range" of such gun. In fig. 1, ^:> is the point-blanc as understood by us. This definition makes point-blanc to depend on the charge of powder, or the same thing, velocity of shot. The French point-blanc, is that point ir, in fig. 2, where a shot in its flight intersects a second time the line of metal prolonged. The shot does not rise in crossing the first time at a as is generally supposed, but the line of metal descends faster than the shot at fii'st gravitates ; but in crossing the second time at ,r, the shot falls faster than the line of metal sight descends. This definition makes the point-blanc to depend partly on velocity of shot and partly on shape of the gun. Sometimes point-blanc is defined to be the distance at which a shot will strike the water-line of a ship, and then depends on height of the deck from the water. 108 EANGES OF GUNS. > The comparison will be continued between tlie 32 and 18-pdrs. in respect to range, as it lias been made in respect to penetration. The tables of ranges will show more fully those of other varieties of guns. The point- blanc range of the long 32-pdr. is 400 yards ; that of the 18-pdr. is 2Y5 yards. At 2 degrees of el- evation the 32-pdr. throws 1,200 yards; the 18-pdr. only 900 yards. At 10 degrees of elevation, all that a ship's ports admit of, the 32-pdr. throws its shot to the dis- tance of 3,000 yards ; the 18-pdr. to 2,500 yards. The lighter medium guns with less charges of powder have less point-blanc range ; and to produce similar ran- dom ranges, they require greater elevations. Guns also of lighter cali- bre, having less point-blanc range, require greater eleva- tions to produce similar ran- dom ranges : tlie random^ or random range, being any range beyond point-blanc. RICOCHET FIRING. Kicochet firing from a gun that is level or not ele- EICOCHET FIRING. 109 vated more tlian 2 degrees, and placed near tlie level of tlie water (the nearer the better), may be resorted to with advantage in a smooth sea, and will under such circumstances give a greater range than can be obtained by any possible elevation admitted by a ship's ports. But ricochet shot will not retain pene- trating velocities at such great distances as shot fired with an elevation, evidently because of the force lost when they strike the water. When balls in ricocheting rebound with a less angle than Y degrees, their penetrating power is lost. At the end of their flight, they do not rise at any angle, but literally roll on the water, and are then of service only against boats and small craft. If then the water be smooth, and mere range be the object as in the case of acting against troops or craft, ricochet firing will be j^erhaps the most effective. But if penetration at the greatest distance be the ob- ject, it is best accomplished by resorting to all the elevation of the piece that circumstances will permit ; Avhicli, as before remarked, in a ship's j)orts when on an even keel is usually not more than 10 or 12 de- grees. Ricochet shot, when their velocities become low and they rise but little from the water, deflect from the line of aim at large angles. Ricochet shot deviate from the line of aim more than shot flying wholly in air, because the opposite surfaces of the shot are ex- posed to the friction of mediums, air and water, having greatly different densities. In a sea-wa}', especially in firing to windward against the steep sides of waves, ricochet shot bury in the water and soon lose their velocities. 110 SHELLS. SHELLS. Sliells may be fired from guns of any calibre or weight. There are in service, shells for 18, 24, 32, and 42-pdrs., as well as for the 8, 9, 10, and 11-inch shell-guns. The diameter and windage of shells are precisely those of shot for guns of corresponding calibres. The "weights of shells, lea^'ing out fractions, are for 18-pdr. guns, 12 lbs., for 24-pdrs., 16 lbs., for 32-pdrs., 25 lbs., for 42-pdrs., 35 lbs., for 8-inch guns, 50 lbs., for the 9-ineh, 10 lbs., for 10-inch guns, 97 lbs., and for fl- inch, 130 lbs. The thickness of shells is various, from 0.8 of an inch for the 18-pdr., to 1.8 inch for the 10- inch shell. The fuze-holes are .6 of an inch. The metal about the fuze-hole is reinforced to support the fuze more firmly, and to compensate for that taken out by the fuze-hole in order to preserve concentricity. Shells have another hole, very small, for the purpose of filling them with powder after the fuze has been placed. To prepare a shell for service, it is first bouched to screw in the metal fuze, then strapped to the sabot, which is a block of Avood turned in a lathe to a diam- eter a little less than that of the shell, and also made tapering to correspond with the slope in the chambered gun. The fuze is screwed in, the powder filled, the patch pasted on, and the shell is ready for service. The bursting charges of poAAxler for shells are, the 32-pdr., -9 lbs., 8-inch, 1-85 lbs., 9-inch, 3 lbs., 10-inch, 4 lbs, and 11-inch, 6 lbs. The Ordnance Regulations are very full and ex- plicit on the subject of shells, to which the reader is referred. Of the shells on board ship, a small number are POnSTTIKG AND SIGHTING GUNS. Ill kept fazed with 5-second fazes, and filled ready for immediate use; a portion are kept fazed, some with 10 or 1 5-second fazes, but not filled ; and others are kept neither fazed nor filled, as a reserve to be pre- pared when necessary. Shells have neither range nor accuracy in distant firing with low charges ; and when with wooden fuzes as formerly, would not bear high charges without bursting in the gun. Whether this was because the force of powder broke the shell, or split the faze, or drove the shell with such velocity against the air that it forced in the burning fuze, is not known. Re- cent experiments induce a belief that all these causes operated. Hence thicker shells, and metal fuzes screwed into the shell, are now used, admitting of heavier projectile charges for long ranges. But where shells are intended for short ranges only, as they are to bury in, not perforate a ship's side, they require only low velocities. To prevent the extinguishment of fazes by water in ricochet firing, they are fitted with a means of con- traction to the exterior escape of flame, which repels the water, preventing its access to the seat of ignition in the tube of the fuze. SECTION VIII. POINTING AND SIGHTING GTTNS, PoiNTmG a gun, is giving a desired direction to the axis of its bore. This may require two motions of the gun : one in a vertical plane, on the trunnions as a centre ; the other in a horizontal plane, by means of 112 SIGHTING GUJSrS. the crows and side-tacMes. These two motions will be distinguished, the first as giving direction in eleva- tion, the second as giving direction in lateral aim, or simply in aim. In order to obtain any accuracy of pointing either in aim or in elevation, some means must be attached to a gun, by which the direction of the axis of the bore may be known. The line of metal top-sight is highly deceptive as regards direction in elevation, and the line of metal side-sight is highly deceptive as re- gards direction in aim. When by the line of metal top-sight a gun is apparently level, its axis is in reality elevated. And this deception is greatest, in guns having greatest dispart. But the tojD-line of metal sight gives accuracy of direction in aim, provided there be marks placed on the top of the gun in a line where a plane perpendicu- lar to the axis of the trunnions, and passing through the axis of the bore, cuts the surface of the gun. A sight secured to the gun in this line, and laid parallel with the axis of the bore, will give the direction of the axis both in aim and in elevation. The short dis- part-sight which was ordinarily placed on guns, ex- tending from the base-ring to a point between the trunnions, is constructed on this principle. DISPAET-SIGHTS. In fitting a dispart-sight, therefore, it will require two adjustments ; one to bring it into a plane perpen- dicular to the axis of the trunnions and passing through the axis of the gun ; the other to make it par- allel with the axis of the bore. Unless the points where the plane perpendicular to the axis of the tninnions cuts tlie muzzle and base- SIGHTI^'G GUNS. 113 ring, be marked before tlie gun is put afloat, there will be great difficulty, or impossibility, in sighting the gun correctly on board ship. These points are then first to be determined whilst the gun is on shore ; and it is done thus : Let the figure 1 be the section, at the trunnions, of a gun placed on skids in the plane g Ji ; and ah c d, a rectangular frame, or trunnion-square, having the two legs a b and d c equal, set over the gun, with one leg resting on each arm of the trunnions. Then 5 c is levelled (a spirit level being placed upon it), by driv- ing the wedges e oy f\ and since h c and i Tc are par- allel, * Tc will also be level. Kg. 1. In figure 2, let ah che a. section at the base-ring, of the same gun (having the trunnions level), and d e f & square and plumb-bob, set on the base-ring ah g; as d e'ls made horizontal, where it is tangent to the base-ring, as at c, there the vertical plane, at right angles with the axis of the trunnions, and in the axis of the bore, will cut the base-ring ; and there the sight- mark on the base-ring must be placed. On the base-ring immediately in rear of the vent- patch, the founders generally make a mark from which SIGHTING Gtnsrs. 115 they adjust tlie axis of the trunnions. Of course this mark ought to be the same as that found by the pro- cess described, and when not effaced by rust will serve as a verification. The place for the mark on the muzzle is detei'- mined in the same manner ; and a line joining these two marks shows where the plane perpendicular to the axis of the trunnions cuts the gun, and is the line along which the dispart-sight must be secured. The other adjustment of the dispart is more simple, and may be made on board ship. In figure 3, let a b he the centre line of a bat- ten, having parallel sides, and driven tight in the muzzle of a gun. This centre line will then coincide with the axis of the bore, and that axis produced. Measure, with large calipers, the diameter of the gun at df the muzzle, and at e cj the base-ring. Half the difference of these diameters is the dispart. On an- other batten, secured to the first at right angles, lay off i c, equal to the dispart plus the height of the vent- patch h above the base-ring. The line A e, joining h and c, is that to which A Js, the top of the dispart-sight h h I, must be made to coincide ; because h c is parallel to a b, the axis of the bore. As a verification, measure m n, which should be found equal to b c. So long as from the relative positions of a gun, and the object aimed at, the eye placed at a, fig. 3, and looking along the dispart-sight, can see the object on the line A Ti prolonged, the dispart may be a perfect sight, and nothing better be wanted, or attainable. But when, as in fig. 4, a gun is pointed at an ele- vation to reach a distant object o' in the horizontal plane, if the eye at e look along the dispart-sight e l\ the object o' cannot be seen. To see it, the eye must be raised to ?/, so that u Js is a horizontal line. As 116 SIGHTING GUNS. the object d is at a great distance compared with h t, it may be considered as lying in the visual line uh o produced. But to preserve accuracy of sight, it is necessary that the eye, when at ?/, should be in the vertical plane of the axis ; for if to the right, or to the left of this plane, the line of sight, taken over the dis- part-piece h, will be at an angle with the axis of the boi'e, and consequently the direction of aim will be erroneous. To assist the judgment in preserving the eye in this plane, a tangent slide-sight is generally used. The slide-piece of this sight has a notch in the top, and moves up in a vertical groove. When the slide is down, the notch is at e, and a line from e to h (the top of the dispart-piece secured to the gun and equal in height to h I, the thick end of the dispart-sight in iig. 3) is a dispart-line, corresponding exactly Avith the top of a dispart-sight. And when the gun is elevated, and it is necessary to raise the eye to u> in order to see the object o', if the notch of the slide be also raised to u, the eye placed in that notch, is certainly in the vertical plane, and the direction of aim is perfectly true. There is another, and no less important advantage which attaches to the tangent sight. If the object o' be 2,000 yards distant, l)y the table of ranges 5 de- grees of elevation with the horizon may be necessary to reach that object. The tangent sight enables one to know when, by the roll of the vessel, the gun is brought to this elevation with the horizon, and indi- cates the precise moment for firing. If, in fig. 4, the axis of the gun be supposed ele- vated to 5 degrees, and the gun and object o' be in the same horizontal plane (the object being so far distant that it may be regarded as lying in the line of sight SIGHTING GUNS. 117 uh produced), p equals the angle of elevation, and equals also the angle uh e; therefore uh eia taken as the angle of elevation, and in the present instance is equal to 5 degrees. But e w, being perpendicular to e \ is tangent of the angle eh u, or the angle of elevation, to the radius 6 h. Whenever, therefore, by sliding up the piece, e ti is made equal in length to this tangent of 5 degrees, and by the roll of the vessel, or movement of the quoin, the points u and h are brought in a line "s^dth (?', it follovs^s that the gun is then mathematically cer- tain to be at an elevation of 5 degrees with the hori- zon ; and that if such an elevation will reach 2,000 yards, the object o', at that distance, must in theory be reached. And similar results will tahe place at lesser angles, for lesser distances, according as e u \s made in length to correspond with the tangents of lesser angles. In practice, then, knowing the distance of an ob- ject, and the elevations necessary to reach it, if the tangent-slide be graduated for degrees, set the slide so high as to correspond to the number of degrees of elevation for that distance ; and when, by the roll, the three points, the notch in the tangent-sight, the top of dispart, and the object are in one line, fire, and the gunner Avill at least be more likely to strike the object, than if he depended entirely upon the judgment, with- out any instrument by Avhich to guide or aid it.* The graduations on this sight are determined thus : The natural tangent of one degree, with a radius of one foot, is .01745 of a foot. Consequently, the tan- gent of one degree with a radius of 3 feet is .01745 * As now mounted, gnns cannot be " fired flying.'' Hence much of the advantage really belonging to the tangent-sight is lost. This loss, es- pecially in quick rolling steamers, must be cured by an improved carriage. 118 SIGHTING GUNS. multiplied by 3, or .05235 of a foot ; and in the same manner for any other radius. Although not strictly correct, the tangent of two degrees is taken to be twice that of one degree, tan- gent of three degrees, three times the tangent of one degree, and so on as high as 10 degrees. It is more common, however, to graduate tangent- sights for the ranges in yards corresponding to degrees of elevation for different calibres and weights of guns. Manifestly, graduations for distances vary on sights intended for guns of different calibres and weights ; and graduations for degrees vary with the lengths of guns, because the lengths of radii then differ. Gradu- ations for distances vary also according to charges used in the same gun. For example : suppose, in the long gun, the dis- tance from the tangent-sight to the dispart-piece be four feet. Then the tangent of 10 degrees with that radius, found in the manner shown, is .6980 of a foot in length. This length, laid off on the scale, may be marked as 10 degrees ; and if the graduation is for distances, mark 3,000 yards for full charges, or 2,500 yards for the reduce. All three of these graduations, 10 degrees, 3,000 yards, and 2,500 yards, may be placed against the same mark, but on different sides. Usually, however, the graduations are only for dis- tances, it being considered useless and confusing to mark the corresponding degrees. If tangents are to be fitted for another gun, lighter, and of less length, the radius being less, the tangents will also be in length less for degrees, but proportion- ably greater for distances ; because guns fired with less charges require greater elevations. It is no valid argument against tangent-sights, to say, that they are of no use when the enemy is ob- POINTING GUNS. 119 scured by smoke, for this is as true of the dispart as of the tangent-sight. A prominent advantage of the tangent-sight, is, that it puts the battery measurably under control of one dii'ecting intelligence, the commander, on the quarter-declv. He, from his elevated position, and un- obscured vision, as well as on account of his superior judgment in estimating distance, can better determine that of an enemy than those can, who are beclouded on a smoky main-deck in the heat of action, and have such an imperfect view of the enemy as barely to know his direction. If the commander judge the enemy at a particular distance, say 800 yards, and orders the tangent-sights set for that distance, seamen fii'ing when they barely discern that the enemy and the sights are in a line, will be ordinarily sure of striking him. And so if the commander observes his shot to overreach, or fall short, he can, by means of the tangent-sights, order the battery set at a less or greater elevation to suit the case. And if heavy broadside guns were mounted on chassis or slide-carriages, working around fixed pivot- bolts, on circles graduated for concentration of fire at an average distance of broadside fighting, say 600 yards, the commander, by observing the degree of training necessary with the gun under his own imme- diate eye on the quarter-deck, and knowing also that when one gun set at a given graduation bears, every other gun set at a corresponding graduation must also bear, might be able to control the whole battery, in aim as well as in elevation. Hitherto in marine engagements, for want of some arrangement by which to place the fire of a battery under control of a skilful head, not one shot in thirty has taken effect on an enemy's hull, even in some 120 POINTING GUNS. actions noted for tteir close and destructive character. For example, in the action between the United States and the Macedonian, but 95 of the States^ shot sti'uclc the Macedonian's hull, and but 5 of her shot struck the States' hull, and no damage was done to her aloft. Yet it is fair to suppose that those ships fired each 50 broadsides, or together 2,500 balls. In the battle of Navarino, fought at anchor in smooth water and at exceedingly short ranges, the Albion seventy-four alone fired away 52 tons of shot equal to 98 broadsides single-shotted, or nearly 4,000 balls, and }'et did not sink a ship. The Genoa seventy- four, in that action, lay 3i hours with her broadside sprung upon her antagonist, so near that the whites of the Turks' eyes Avere visible, and fired away 7,000 pounds of powder with shot in proportion, and neither sunk nor destroyed her antagonist. So say the au- thorities. Such results, though common hitherto in naval combats, cannot but strike the general mind as re- markable. Yet they are the natural consequences of the imperfect or total want of control on the part of a commander over his battery whilst in action ; and of the crowded, obscured, and confused state of things which, in battle, exists on the gun-decks of a vessel. On those decks, let any one figure to himself the rap- idly successive discharges of 15 or more broadside guns; the thick smoke thus produced; the crowded action of 200 or 300 men who compose the crews of those guns ; the deafening noise, rushing to and fro of powder-boys, boarders, and others ; the penetration of enemy's shot, scattering of splinters, and explosion of shells ; and he 'will cease to wonder, that, uncontrolled as these guns have hitherto been by any mind free from such confusing influence upon the senses, by far poiNTLNG- Gxnsrs. 121 the greatest part of the shot have been fired at ran- dom, and utterly thrown away. If it were possible always to close with an enemy, and decide actions by yard-arm contests, tangent-sights, and other appliances conducive to accuracy of fire, would be of less consequence.* But such possibility, especially in fleet fighting, more particularly imder sail, does not always exist. The weathermost vessel or fleet may keep its wind, and approaching warily, reaping all the advantages of superior equipment or gunnery, in the end close, only to complete an enemy's destruction. And if the weather-line be determined to close at the commencement of an engagement, it is the lee-line which fights at a disadvantage, unless its batteries and their equipments be adapted to damage the enemy at a distance during his approach. For, if the weather- line coming down fresh, and but little injured, doubles upon the lee-line, thus bringing the whole weather against half of the lee fleet, its fate is very much influ- enced by that manoeuvre. But with well-adapted batteries, equipped so that commanders in the lee fleet can concentrate their broad- sides upon the van ships of approaching columns, and fire at elevations governed by their own estimates of the distances, the scale of advantage would probably be reversed, and preponderate in favor of the leeward line ; unless indeed the attacking columns can come down rapidly before a fresh wind. With the light wind and consequent delay which Lord Nelson experienced at Trafalgar in closing with * The fault most common and to be most carefully guarded against in rapid firing in close action, is that of firing too high. This fault arises from the deception occasioned by the dispart of the piece ; and is most likely to occur in firing with medium guns, which being short have greater dispart. 122 POINTING GUNS. the combined fleet to leewai'd, Lad that fleet been })etter jjrepared in battery, ecj^uipment, and practice, and been managed by seamen skilled in jjerceiving and improving the advantages of their position, the results of the day might at least have been less decisive. At Lake Erie, it was the light wind which delayed Commodore Perry's approach to the British line to leeward, and enabled them, with their long guns, to gi\e for a time a doubtful aspect to the battle of the 10th of September. So also on Lake Champlain a few destructive shots thrown by the American commander, while the British fleet was approaching with a breeze which had nearly failed it, materially contributed to the results of that day.* * Seeing, then, that although gallant men may prefer and determine upon close action, where preeminence in careful equipment of battery, and superiority in gunnery are in a measure lost, it is often difficult or impossible to accomplish such a design ; and since the lee-line must experience a disadvantage unless it can receive an enemy with an effective distant fire, it is manifestly unwise in any nation to treat with con- tempt the modern refinements in equipment conducive to accuracy in distant firing, while other nations are perfecting their gunnery by all the aids which science aflfords.f * These battles, and many others, will be found critically and fully discussed by the author in his " Manual of Faval Tactics," D. Appleton & Co., New York, 1859. t "With the introduction of steam, all this may change ; and whilst the received theory is that steamers need batteries peculiarly adapted for fighting at long balls, it may turn out in practice, that inasmuch as their closing and grappling power is greater, the inclination, natural in combat- ants, to close will not be wanting, and therefore close action be more common between steamers than It has been with sailing ships. EEITNEMENTS IN EQUIPJtEKTS. 123 The argument, that because we did well witliout these refinements in the last war, Ave can do well without them in another, is absurd. AVith equal pro- priety might the Indian, who had conquered another tribe whilst that tribe fought like his own with the bow and arroAv, boast that with the same weapon he could again succeed against the same enemy, armed with weapons derived from the arts of civilization. The savage in strength, activity, bravery, and powers of endurance, equals the white man: yet he is, with all these gifts, impotent in war against the white, aided as the latter is, in a superior degree, by the de- velopments of science applied to the arts of war. And what is true of savage and civilized people, is true also of two ci^T-lized nations, when either derives from superior knowledge or applications of the arts, an odds against the other.* The contempt for " science," once entertained, may be traced to the fact, that in the great maritime wars Frenchmen, with all their science, were driven from the ocean by practical Englishmen. But the French marine Avas in those days less scientific than now, and was not at all skdled in practical seamanship — in fact, little else than a body of landsmen put afloat ; and it is not a matter of Avonder that their science AA'as un- available. NoAV, hoAveA'er, the French are admitted to be superior seamen, and to afford incontestable proof that superior knowledge, and familiar practice, do combine most advantageously in the same individuals. The difficulty vrith France, as the Prince de JoiavUle showed in his celebrated pamphlet, lies not in a lack of present efficiency, but in the Avant of maritime re- * These remarks, first published in the edition of 1845, were then eminently appropriate, and it is believed effected much good. They are as true, though fortunately not now so necessary as then. 124 REFINEMENT IN EQUIPMENTS. sources to supply the loss that would be occasioned in a single battle. Three successive and eminently disas- trous campaigns, those of Moscow^ Leipsig, and Paris, failed to exhaust the military resources of France ; yet the loss she would experience, even in gaining a single naval victory, would render her powerless to meet the fleets which the vast naval resources of England could forthwith equip. Without the aid of art and science, France as a maritime power is nothing ; with it she is highly respectable, and if natural resources were super- added, she might contend for supremacy on the sea as well as on land. In dwelling thus upon the importance of bringing to naval equipment and practice in gunnery, all the aids which science can bestow, reference is had to what was a prevailing prejudice now happily fading from the service. But, if the great object for which the country maintains a large establishment in time of peace be constantly kept in view, namel}', that of preparation for war Avith the maritime powers of Eu- rope; and if the inevitable tendency of things to a collision be considerately watched, officers will regard no preparation as complete, so long as in any degree inferior, or not superior, to that of any other nation. Whether or not the war complement of creios be constantly maintained in time of peace is of little mo- ment ; for in case of sudden war, short crews are easily recruited from commerce laid up at home, or sold abroad. But defective batteries cannot be amended at all abi'oad, or easily at home ; and defective equip- ments, for want of knowledge to produce them, or if produced to use them, would not likely become sud- denly available. It is, therefore, of the utmost conse- quence, that a perfect battery, completely and refinedly equipped, should be provided in every vessel ; and PEACnCE SHIPS. 125 that tLe use of these equipments should be rendered familiar by continued instruction and practice ; because these are what, if neglected in peace, cannot be readily supplied in the event of sudden war. TAEOET PRACTICE. The student who has carefully gone through with the compendium of principles, contained in the fore- going pages, is prepared, and he is recommended, to continue his investigations, by perusing authors who treat the subject, in divisions, more elaborately. And this course is recommended with a view to beneficial practical results; for mthout the knowledge which will be obtained b}^ this iuvestigation, an officer is not in the highest degree prepared to control the construc- tion, adaptation, or equipment of a battery, or to use it with full effect either in service or on practice ground. One who knows principles, knows the causes, independent of pointing, which produce inaccurate firing, and knows also which of those causes are under control. By controlling and modifying them, a good deal of the uncertainty attendant upon firing with great guns may be obviated. In smooth water, or on shore, the aiming of great guns is a deliberate mechanical process, requiring only a knowledge of the distance of the object, and the ele- vation given in the practice tables as necessary to reach that distance ; for if the gun is steady, and the sights fine and properly adjusted to the gun, when the object is seen through the sights, as the visual ray in a uniform medium is always a straight line, the direc- tion of aim must be perfect. But to form expert Tnor rine gunners, it is necessary to train the nerves, the eye, and all the faculties concerned, to catch a quick 126 PEACTICE SHIPS. sigLt, under a motion such as a ship has at sea, and to fii'e at the instant when by this motion the gun is pointed so as to strike the object. For this purpose, practice schools are in Europe established afloat. As it is not always convenient to station " practice ships " where there is sufficient undulation of the waves to produce this motion naturally, an artificial platform motion is obtained, which veiy closely resembles the motion of a ship at sea. This motion, and the method of producing it, are often seen in the miniature ships attached to mantel clocks. On the platform, there is a gun mounted, which is provided with a tangent- sight, and a percussion-lock, but is not loaded. At this gun seamen are trained, under the direction of in- telligent officers. The tangent-sight is set to corre- spond with the distance of the object. Then, to prac- tise the seaman who is under training, the imitative motion is given to the platform. At the moment his eye catches the sights precisely in the direction of the object, he pulls his lock-string, and explodes the wafer ; and at the instant it is heard, the wheels are set, so as to preserve and continue the j^recise direction of aim as it existed at the moment of explosion, for the delib- erate inspection of the instructing officer. The eifect of such training, added to the science applied in the perfection and ec^uipment of batteries, must inevitably pi'oduce a certainty and destructive- ness in marine gunnery hitherto unknown, and which may overwhelm with surprise and dismay, those who ^vill not heed what is, in this respect, being accom- plished by their neighbors. Target practice at sea would be more common but for the great and troublesome preparation it is usually made to involve, such as rigging and fitting out an elaborately-prepared target, Avhich it is felt must also PEACTICE SHIPS. 12 Y be recovered at tlie conclusion of the practice; but what is worse, as this trouble is greatest in rough weather, the very time when practice is most valuable, it becomes least frequent. If, therefore, a tight beet- barrel, or several of them be kept ready, ballasted at one end with sand enough, secured there in a bag, to keep the other end always up, and a flag placed to fly from that end, such a barrel could be thrown over- board in a sea-way, and after practice at it, be left, without the delay and trouble of recovery, because of no value. True, such a target would be often invisible in the trough of a sea, biit a very prominent object on the crest of a wave. If, in the service, any one fault or neglect is greater than another, it undoubtedly is the utter want of fa- miliarity with the care and management of guns cast adrift for exercise, or for fighting, in a sea-way. Note to page 68. The detonating powers spoken of in page 68 are usnally the fulminate of mercury, a salt which results from a union of fulminic acid with the oxide of mercury. AH the fulminates, as well those" of gold and silver as of mercury, readily and violently explode under percussion or friction, in which re- spects the two former are most remarkable, that of gold going off, as is said, almost under the scratch of a feather. Hence the preference for mer- cury, also because cheaper, and because the oxide of it is most easily produced. The name fulminate comes from the Latin fulmen, which signifies lightning. PART n. SECTION I. METAL FOB GTWS. — IKON. — SKELTING. — KATIOXALE OP THE PEOCESS OF SMELTING. — WEOUGHT-IEON AND STEEL. PUDDLED STEEL. — CONOLTJSIOK. The material used for the construction of ships' guns is cast-iron. Boat-guns might also be of cast-ii'cjn. if they ■were not intended besides for field use, where the extent of the recoil possible admits the advantage:'::? use of a liofhter g-un, such as can be made from 1:>rcirLze. which, though a softer metal than cast-iron, is toucher, less easily rent asunder, and if overstrained, always gives warning by an alteration in shape, or by a longitu- dinal external opening.* In these respects, bronze has the advantage over cast-iron ; but its cost, if nothing else, would render it impossible for heavy batteries, being worth 30 cents per pound, whilst cast-ii'on guns cost fi'om 6 to 9 cents only, according to weight ; the larger guns, as the 11-inch, costing highest per pound. A bronze gun only fifty times hea^-ier than its pro- jectile, bears a charge of about -^j ; whereas a cast-iron gun sevent"\' times heavier than its shot, has a charge of only about ^. This is because of the greater toughness of the bronze. And if the carriage would bear it, the charge of the bronze gun might be even higher, or the gun proportionally lighter. * See note, p. 208. IRON. 129 Wrought-iron is sometimes used in tlie construction of guns, wHcli metal is tough because fibrous ; whilst cast-iron, being granular, more readily fractures. A wrought-iroi] gun, if of good material and perfect weld throughout, is vastly stronger than a cast-iron gun of similar proportional weight — stronger even than a bronze gtin. But both the material and the weld are of necessity uncertain, and the comparative cost very great. Nothing is gained on board ship by a piece lighter than is made with cast-iron, because all the weight taken from the gun must be there added to the car- riage as an increase of strength required to control and sustain the increased velocity and shock of recoil, which is always greatest with the lightest guns, the charge of powder being undiminished. If, then, the weight must be on board ship either in the gun or in the equipment, it had, of the two, best be in the gun, where it serves also the purpose of strength ; unless indeed the extra weight of equipment serves also the purpose of facilitating the gun's manoeuvre. Usually, however, the charge on shipboard diminishes with the proportional weight of gun ; and the carriage reduces also in weight, though not so much as the gun does. Thus a carriage for the heavy 32-pdr. weighs 1,200 pounds, and that of the lightest truck-carriage gun of that calibre (33 cwt.) weighs full 1,000. IBON. Iron is the most difiused and most abundant, as it is the most useful of metals, and is found in nearly all geological formations. When it combines ^^dth the earths in a proportion exceeding 20 per cent., they are ranked as iron ores. In England, it combines princi- 130 SMELTING. pally as a carho7iate, in this country as an oxide of iron. There, it occurs in tlie coal regions ; but here it does not. Nor are iron ores of good quality, those which are free from pernicious mixtures, such as sul- phur, arsenic, (fee, here found even conveniently near to the coal formations. And in England, the few ores found away from the coal beds are " hematites," a spe- cies of oxides, and are those there used for casting cannon. It is natural, thg,t ores found near the bituminous coal-beds, which are all more or less sulphurous and pervaded by the sulphuretts of iron, should partake somewhat of that quality, also incline to be carbonates. So it is natural that calcareous ores should also incline to be carbonates, more than those ores found in sili- cious or aluminous formations. SMELTING. The metallic iron is extracted from the ore, by a process called " smelting." 1st. As a preparatory step, the ore is roasted, to volatilize the arsenic or the sulphur, to dry out mois- ture, and to burn away the carbonic acid of the car- bonates when present, just as in a lime-kiln, reducing the carbonate to an oxide. But the oxide so produced, never comes up in quality to the natural oxide as quarried from the mine. Roasting renders the ore also in some degree friable, and the lumps more easily reduced by the pounding mill, as they must be, to the size of a nut or less. 2d. The fuel is prepared. It consists of wood- charcoal, or of anthracite coal, both which are nearly pure carbon; or of raw bituminous pit coal; or of coke, which is bitumin6us pit coal charred, as wood SMELTING. 131 is, by driving off the bitumen and other volatile parts, leaving only its carbon as coke. 3d. A quantity of the carbonate of lime, either oys- ter-shells or limestone, is provided for use as a " flux." 4th. A strong brick furnace is constructed, from 30 to 50 feet high, egg-shaped, with the point up, lined with fire-brick, open at the top for feeding, and with a receptacle at bottom to catch the molten material of the ore as it flows ; for the ore all melts, the eaiiihy and metallic portions both, and flows down together. 5th. The furnace is " charged," at the top, by throwing in kindling, then coals or coke, whichever of them is to be used as fael, then ore and flux min- gled. By repeatedly alternating a further supply of fuel, ore, and flux, in this order, the furnace becomes filled up to the top — " charged." The furnace being thus charged, the fire is kindled at the bottom, and combustion of the fael is promoted by a strong " blast," kept up with a steam-engine or water-power ; but the mass of the charge does not get into a regular perfect heat under several days. This blast is usually cold (with cold aii'), though sometimes it is hot (with heated air), for charcoal and coke- charged furnaces. It is thought to be generally, if not alwavs, a hot blast when anthracite coal is the fuel used. Perhaps it is so also mth raw bituminous coal. And other things being equal, the cold-blast charcoal iron will rank first in quality, the hot-blast charcoal iron second, the anthracite iron third, then the coke, and last the pit-coal iron ; which last is both cheap to produce, and inferior in quality. For casting guns, the best grade of coal-blast charcoal iron is that always selected.* * Founders do often, if not always, warm up the blast (even when they style it cold) to about the temperature which will melt lead — say 500 or 600 de!?"ees. 9 132 RATIONALE 01^ THE PROCESS OF SMELTESTG. RATIONALE OF THE PROCESS OF SMELTING-. The first action of tlie fire of a smelting furnace, after it gets into fall blast, is to drive off the carbonic acid of the limestone flux, precisely as occurs in a lime- kiln. Then the lime which remains in the furnace, by mingling with the rock or earth of the ore, causes the fusion of both ; when but for this union of the earth of the ore and the lime, neither of them would fuse, only vitrify as clinker. The carbon of the fuel unites with the oxide of the ore, forming carbonic acid gas, which escapes, leaving the pure iron. Another portion of the carbon then unites with the pure iron, forming a carburett of iron, termed also a carhide, which is a fusible substance, whereas the simple iron, or its oxide, will not fuse. Only the carburett, popularly called carbonized iron, is fusible. Both the earth and the iron of the ore being thus separated from each other, and each newly combined, the earth with the flux, and the iron with the carbon, in their new states both gradually continue to melt away, and flow together, through the aperture in the bottom of the furnace, into the receptacle below, where the molten iron subsides, being heaviest, and the mol- ten earth, termed " slag," which is easily distinguish- able by its color, floats at top, and as it accumulates, oA^erfows through the waste holes left open high up in the sides of the receptacle. When the iron is per- ceived to have accumulated so that it has risen to the Avaste holes and begins to overflow through them, the receptacle is tapped at the bottom, and the iron draAvn into rude sand pig moulds, where it cools as pig iron. When the pigs have become cold and are broken, those of them which show a fracture, fine-grained and white, are known by that sign to be hard and brittle, EATIONALE OF THE PEOCESS OF SlIELTING. 133 or " high iron ;" and it is so, because containing com- paratively a lesser proportion of carbon, which again arises maialy perhaps trom a lesser proportion of coals in the charge. Those pigs which, on the other hand, display a dark coarse-grained fracture, having perhaps an excess of carbon in an uncombined state as " graphite," are inferior in quality, because the metal is soft and weak. But such of the pigs as show a coarse-grained dull gray fracture, are of the iron which best unites that degree of hardness and tenacity requisite for guns, being for that use the best-propor- tioned union of the carbon.* The two inferior qualities of iron noticed, the one white from deficiency of carbon, and the other dark from an excess of it, are so as already remarked, owing to a disproportion in some of the materials with which the furnace is charged, or of the blast ; and it is to be observed, that the ore of each locality requires its own peculiar treatment, both in the blast and the charge ; and furthermore, that this treatment varies even with the state of the atmosphere, and condition of the weather, so that proportions which at one time and season of the year are correct, are not so at another. Workmen, by observation, learn to detect very soon from appearances what is wrong, and to apply the remedy which will produce white or gray iron at pleasui'e. The proportions with Avhich furnaces are charged may be set down as averaging in weight, two of fuel, two of roasted ore, one or less of flux, and the metal resulting as less than half of the roasted ore. * Though ranked lower in quality, high iron is best for many purposes. It is especially in request for malleable castings, because it anneals well. Annealing is only roasting out the carbon from the cast-iron ; and the white iron anneals best and easiest, because it has less carbon to be ex- tracted. 134 WROUGIIT-IRON AND STEEL. WEOUGHT-IRON AND STEEL. Wrought-iron, is cast-iron (a carburett) reduced to the pure metallic state by burning and working out all the carbon and remaining oxygen. The process which effects this is termed " puddling," and consists in stirring the molten ii-on, collected in sand pools or puddles, whilst it is cooling in them ; which operation brings the carbon of the iron, and the remaining oxy- gen of the iron, into union for combustion of the car- bon. Continued stirring, further exposes the remain- ing carbon in the iron, to a union with the oxygen of the atmosphere, for further consumption, as carbon in any state or condition is consumed when united, under heat, with oxygen, and converted to a carbon acid, or to a carbonic oxide. Whilst the carbon is thus burning out, the iron by cooling thickens to a certain consistency, in which state it is gathered into balls, called " puddle-balls," of convenient size for management. These " balls" are next placed under a trip-hammer, then in the rolling- mill, and by hammering, reheating, and rolling, they have the slag and other earthy impurities worked out, the product being pure metallic bar and rod-iron. In this pure metallic state it is malleable, and will forge, or burn, but will not melt. It is to be remarked, that by rolling, the iron be- comes fibrous, with a grain which lays in the direction of the roll ; and in forging the iron to any particular use, the direction of its grain is always taken into account, and retained in a position longitudinal to the work. , Steely is the product of a recombination of the me- tallic iron with a minute proportion of carbon, which though is more intimately and evenly diffused in steel, PUDDLED STEEL. ♦ 135 ttan it is in cast-iron. Ttis reunion of tlie iron and carbon is effected by a process termed " cementation," whicli is simply haking carbon into the iron. Imbed bar iron in pulverized charcoal ; cement it, thus im- bedded, in a crucible to exclude air ; then expose the crucible and its contents to a high heat, and as the carbon cannot consume for want of air, it becomes red-hot, and burns or hahes itself into the iron.* This makes " bar-steel," called also in some conditions blis- tered steel, which is a metal that forges, and is more ductile than bar-iron. But because of the carbon the bar-steel contains, it will also melt. When it has been melted and run into ingots, it is called " cast-steel," a metal which also forges, and from which the finest cutlery is fashioned. Eefined steel, therefore, which has about one per cent, of carbon, is a metal that both forges and melts. Cast-iron, with 5 per cent, of carbon, only melts. And wrought-iron, having no carbon, only forges. The steel appears to have carbon enough to render it fusible, but not enough to prevent its forging. PUDDLED STEEL. It follows from the foregoing, as cast-iron has 5 per cent, of carbon, steel 1 per cent, and wrought-iron none, that at the period of the puddling process when all but 1 per cent, of the carbon is worked out, the metal io I'eally steel. Hence it is commonly said, that all wrought-ii'on has once been steel. And if in the puddling process, at the period when it is steel, the * In tlie foot note, page 133, it is said malleable castings are bv an- nealing or roasting out carbon. The text speaks of bar steel as iron^ith carbon 'baked in. Eoasting, implies escape and free circulation; baking, confinement and no circulation. 136 PUDDLED STEEL. furtlier escape or consumption of carbon be arrest- ed, by piling on ashes or excluding the air in any other way, the puddle balls will cool as puddled steel. When reheated, the balls will roll into plates, and though not so readily melted as the cemented steel, will yet fuse, but under a much higher heat than cast- iron requires. Puddled steel is comparatively a cheap, coarse article, and appropriately mentioned in this work be- cause of the proposed use of the metal for plating ships. Refined steel, made by the process of cementa- tion, could not be produced in sufficient quantities for this purpose. The Bessemer method of burning carbon out of cast-iron to make it steel, is to inject air to the molten iron, which produces a blue flame at the surface as evidence of the consuming carbon. This metal is afterwards gathered into balls, but requires little stir- ring, only enough to bring its consistency down to the handling state. CONCLUSION. Apart from the quality of the ore, whether a hema- tite, an ordinary oxide, or a carbonate ; and apart from the impurities the ore may contain, as sulphur, arsenic, etc. ; the characteristics of iron, as used in the arts, seem to depend upon its non-combination, or upon the proportions and mode of its combination with carbon. This, indeed, together mth its thorough separation from slag, seems a key to the whole mystery of iron, and to be the principle on which all the phenomena observed, when working it in its various states, are ex- jjlainable. And if it be really as it seems, then this one established principle, laying at the foundation of the subject, although expressed in a few lines, is better MOULDING GUNS, ETC. , 137 than a quarto volume of insulated facts, many of them when unexplained appearing contradictory, therefore confusing and perplexing, darkening rather than en- lightening. Facts are good for nothing, or but for little, except as they conduce to a theory; which theory, when once well established, is simple of com- prehension, easily remembered, and serves in lieu of a cumbrous confusing mass of facts. SECTIOE^ II. MOtlLDING GUNS, ETC. CASTING AND WOEKING THE lEON. MOULDING GUNS, ETC. The moulding earth is a loam, sand and clay, in such proportions, natural or artificial, as contain clay enough to give consistency and cohesiveness to the mould and prevent its crumbling, yet not such an excess of clay as will cause the mould to shrink and crack when hardened, as it has to be by baking. The pattern is of hard wood. For guns not heavier than 24-pdr. (and often for those heavier) it is in two pieces, as divided by a plane cutting the axis of the gun and axis of the trunnions. Or if a breeching-ring is to be cast on the cascable, the plane of division cuts at right angles with the trunnions, so that the half- pattern will withdraw from the sand of the moulds. These half-patterns are moulded each in an iron flask, which flask, with the sand and pattern it contains, is not too heavy for handling with the aid of purchases and cranes. With this style of pattern and moulding, 138 MOULDING GUNS, ETC. strengthening and ornamental bead-rings may be cast on tlie guns. But for the heavy guns now becoming common, a half-pattern is too heavy for handling. Consequently the division is into a greater number of parts, sometimes six, made by cutting transversely in- stead of longitudinally, and some of these parts may be again subdivided lengthwise. Thus the muzzle part is a separate piece, and if it has a ring on it, so that, if moulded as one, it will not draw out from the sand in a cylindrical flask, the pattern must be subdi- vided in direction of the axis and made into half-pat- terns. The chace is another -part, and that, when moulded in a cylindrical flask, will withdraw fi'om the sand by its larger extremity. The trunnions are two other parts of the pattern, the reinforce another, and the base of breech still another. These several parts are capable of being handled and moved with ease, and when baked hard are put together so as to form one mould, which is then set upright in a large deep pit, with the breech end down, and surrounded by well-packed sand to fill the pit entirely. Usually (and always until of late) guns are mould- ed to be cast solid, with no core at the centre to form a bore in the casting. But to obviate an evil, supposed to result from the irregular cooling of large masses of metal from the molten state as run into heavy cannon- moulds, successful experiments in moulding with a core have been made. The Ordnance Report, p. 194 (quarto edition, H. C. Baird, Philadelphia, 1856), re- marks, that " the endurance of guns cast hollow, greatly surpassed those cast solid, in every case, where both were cast in pairs, at the same time, and of the same materials ; the difference in one case being more than twenty to one, and in the aggregate of all, more than eleven to one." It farther remarks, " that the actual CASTING Airo WORKING TEEE IRON. 139 strength of tlie iron in eacii gun of a j)air as shown by the testing machine remains the same," and infers, that this diiference in strength of guns can be attributed only to the diiference in cooling of a solid and a hollow casting, the hollow being that Avhich exhibits most endm-ance under proof charges. CASTING AND WORKING THE IRON. The mould being complete, the iron flask contain- ing it is set vertically, muzzle up, in a pit of sand' (the mould being supposed made for a solid casting), of such body, and under such circumstances, as will en- sure the slowest possible natural rate of cooling, in order that the strain, due to unequal contraction of the outer and inner parts in cooling, shall be reduced to a minimum. The Eeport says, that the strain pro- duced by this unequal cooling " is believed to be ex- erted in a direction tending to assist the central force of a charge in bursting the gun." The "cooling centre" does not, however, always, nor indeed often, correspond in heavy castings with the centre of the mass, owing to the unequal tempera- ture existing in different parts of the pit, and some- times because the mould has not been set in the centre but towards one side of the pit, whence one side cools quicker than the opj)osite. This cooling centre is important, because the metal at it is weakest ; and, if it is in the centre of the cast- ing, is that cut out by the borer. Otherwise, the borer evidently will take out strong metal and leave the weaker. The metal selected, being pigs which show a gray fracture, is piled in an " air famace," where it melts under a flame thrown upon it from wood or bitumin- 140 CASTING AND WOK KING THE IKON. ous coal, by a natural draft.* When melted, how soou to dra-w the metal off into the moulds, is a ques- tion about which founders differ. Some say, keep it under heat several hours, five or six. The Ordnance Report (p. 16), after much experimenting, says: "The results appear to establish satisfactorily the fact, that a prolonged exposure of liquid iron to an intense heat, does augment the cohesive power of the iron, and that this power increases as the times of exposure, up to some (not well ascertained) limit ; and that, if extended beyond that limit, the strength of the iron is thereby diminished." The details of the experiment in ques- tion showed, that up to three hours' continuance in fusion exposed to high heat, the metal increased in strength ; but that the gun cast after three and a half hours of fusion, gave decided evidence of weakness. Reasoning on the subject, the conclusion woiJd seem to be, that the longer iron is subjected to heat, the more its carbon should become diminished, reduc- ing it to a closer-grained, whiter, or "higher" (see page 133) and harder iron. And it appears that iron made high by this process, whilst it has the quality of hardness equally with that high from the smelting furnace, has not its brittleness. Yet, like all high iron, it has the disadvantage of contracting most as it cools ; which disposition to contract, lessens the value of the high iron for large castings, more than it is increased by continuance of the heat, and the gain in strength that continuance is supposed to produce. The Ord- nance Report states (p. 198), " that a reduction of strain in the casting, is of more practical value than an increased strength in the iron ; " and " that, in order to diminish the strain of contraction in larger guns, * An air furnace is one with a natural draft ; a " cupola " acts under a blast. CASTING AND WOEKESra THE IKON. 141 cast solid, we should use tlie softer and less tenacious qualities of iron." Ought it not to have added a cau- tion against rendering this softer iron high, by sub- jecting it too long, or too frequently, in a state of fu- sion, to the action of flame, and thus " burning out its carbon," as the founders express it ? For the more the iron is worked under the action of fire, either by remelting the pigs, or by continuing the flame upon the metal when in a state of fusion, the higher ought it on reasonable grounds to become, because the more wUl its carbon dissipate, and the more intimately Avill that which remains become blended Avith the iron ; in short, the more sieeUike will the iron become.* But be all this as it may, navy guns of the highest calibre, even to 11-inch guns weighing 16,000 poimds, are cast solid, with extraordinary thickness of metal at the breech, and yet none have ever burst in service, nor are they known to have exhibited deficienc}' of strength under proof; whereas the heavy columbiad, a coiresponding gun of the army, has given different results, although cast with ample thickness of parts, and from metal proven to be of the greatest tenacity by specimens subjected to the testing-machine. This difference of strength, as exhibited by different guns of equally high calibre under proof, may be, probably is, due to the superior external form of the navy guns, given to them by Commander Dahlgren. Tlie principles on which the Dahlgren gun is fash- ioned, accord with those discussed in Mr. Mallet's * These views are in accordance with experiments as given in page 22 of the " Ordnance Report," where tlie ratio of increase in strength hy continuing the iron in fusion four and a half hours, is from 1,000 to 1,600, and the ratio of increase in strength from a first to a third fusion, p. 28, precisely the same, from 1,000 to 1,600. That is to say, hoth operations in effect simply serve to reduce and blend the carbon — make in fact the Bessemer steel. See page 136, Section 1, Part II. of this book. 142 CASTING AWD WORKING XIIE lEON. work "On tlie Constraction of Artilleiy." Great praise is due to Commander D. for tlie researcli and ino-euuit}' lie displays in tliis acliievement ; and more T)'et for Ms lioldness and perseverance in successfully coml3ating tlie prejudices of the service against his form of gun, abhorrent to the eyes of all old officers, accustomed as they are to the ancient pattern ; and the praise ^\'ill be more generally accorded as the prin- ciple of his construction becomes more generally kn(.)wn. This princij)le in brief is, that in the outline of a heav)- gun there should be neither an angle, short curve, ri'inforce-band, moulding, ornamental or other- Avdse, nor any other excrescence, but the whole cast as smooth and as rounded as possible. And the prin- ciple is based on a law of congelation, whether of ^\'ater forming ice, or of molten iron to a solid, that such solid is of a crystalline structure, in which the rystals form with their lengthwise direction perpen- dicular to the surface, or surfaces, of the solidifying mass. These lines of crystallization -would, therefore, in the cylindrical parts of a gun, correspond precisely mth the radii of a cross section. But A\hen the cylin- drical part unites with a conical part by an angle, it is evident that lines drawn perpendicular to the tAvo exterior surfaces which form the angle, must meet ; and where these perpendiculars do meet, there is formed a line of irregularity and imperfection in the crystallization, knoA^ai and designated as a " plane of weakness" in the iron. But if, instead of the external angle where the cylinder and cone join, a curve be substituted, the plane of weakness is very much miti- gated, if not entirely removed. By comparing the Dahlgren gun with the shell-guns and others which preceded it, the substitution of the curves in the for- mer for the angles in the latter will be apparent. See c EIFLES AND EIFLED CANNON. 143 Lieutenant Gibbon's " Artillerist's Manual," Van Nos- trand, New York (p. 88). Short guns are cast by pouring metal into the top of the mould, for the fall of the first flow upon the bottom of the mould is not suflSlcient to endanger the mould. It is though destructive to the mould of the present long heavy guns. Hence the syphon method of casting is practised ; that is, the metal is introduced to the mould by an aperture at bottom, and rises from below. And the entrance of the metal to the mould is at an angle which gives a rotary motion to the liquid, the effect being to produce a depression in the centre, and a gravitation to it of the cinder or other earthy impurities which flow in with the metal, and cooling there, are bored out when the gun is placed in the boring-mill. SECTION III. EIFLES AND El F L E D A KN O If . Briefly, the principles of rifle-shooting, and the attain- ment of the accuracy which belongs to it at consider- able distances, with 1)ullets of various shapes, may be summed up as follows : 1st. An elongated projectile, the only shape now used for rifles in military service, derives its accuracy from the absence of all windage, and from its motion of rotation during flight, being always on its long diameter as an axis, which continues uniformly either in the direction of the axis of the gun, therefore tan- gent to the curve of flight only at the moment of leaving the muzzle, or else maintains itself in a posi- tion coincident with the trajectory or curve of flight, 144 RIFLES AND EIFLED CANNON. going end foremost, at all points between the gun and the object first liit. If the projectile is formed with its centre of gravity fixed at or behind the centre of the mass, it will, unless artificial arrangements are placed so as to produce a change, fly with its axis continuing in direction of the bore, therefore not tangent to the curve of flight except at the muzzle. But if, on the contrary, the weight of the projectile is placed towards its forward end, so that such forward end will drop as the curve of flight or trajectory drops ; or if the hind end of the ball is ragged, or ringed, or otherwise so shaped as to cause that end to drag through the air, like the feathers of an arrow : for either reason, the projectile will fly point foremost. And if the projectile makes a circular hole in the target, it is proof that the rifle motion is kept up, also that the projectile is correctly formed ; for striking point foremost wherever the target is placed, whether near or far off, proves the flight to be always point foremost. 2d. The rifle-projectile receives in the discharge two motions, one of progression (some call it the mo- tion of translation), the other of rotation. The motion of progi'ession is derived solely from the charge of powder, and is great or small, in proportion to the charge. Relatively, the motion of rotation does not depend on the strength of the charge, but on the more or less rapid twist or turn given to the rifle-grooves in the gun-barrel, or cannon-bore. 3d. "Whilst a twist of one-quarter in a small-arm barrel of 30 inches gives to a round ball as much ac- curacy at 100 yards as a greater or quicker twist, for longer ranges a greater twist is needed, because it is friction of the air which constantly resists and reduces the motion of rotation ; and in order that it may con- PvIFKEB AND EEFLED CANNON. 145 tinue througlioiit a long range, a quicker initial rota- tion, therefore a quicker twist is needed, even for a ball, and mucli more for an elongated skot, wkick, having more friction surface, experiences greater fric- tion from the air. 4tk. Tke tendency of an elongated projectile, v?^hen fired, to turn over and fly sideways, is very great, and is prevented only by tke motion of rotation on its longer axis. It is necessary, therefore, in order to keep the elongated shot end foremost, to give and to continue that motion of rotation at a higher rate than a ball requires. Hence, for this reason also, the elongated projectile needs a quicker twist. 5th. Accordingly, whilst the old-fashioned military rifled small-arm for a round ball had a twist equal to a turn of once in 120 iaches, the new British Enfield and the Lancaster have a turn in 78 inches, our own regulatioQ rifle a turn in 72 inches (the length of bar- rel being 40 inches), the popular arm a turn in 30 inches. Major Jacob's rifle a tm-n in 24 inches, and Whitworth's a turn in 20 inches. 6th. The greater the twist, the more the force of the charge is expended in giving the rotary motion, and consequently the less in giving the progressive motion to the bullet. Hence the twist is so contrived in judiciously-rifled pieces, as to give what rotation is necessary to meet the conditions required, but no more. A farther evil of too great twist is, that a leaden ball is apt to " strip," as it is tenned ; that is, break or tear out of the grooves, by which both its pro- gressive and rotary motions are very much impaired. 7th. With very heavy shot, such as cannon-projec- tiles, where the inertia to be overcome in producing ro- tation is considerable, an " increasing twist," one which is very small at the beginning and increases gradually 146 KIFLES AND RIFLED CANNON. as it approaches the muzzle, is employed, by whicli great rotation is produced without the danger of stripping. But with small-arm pieces, the twist is generally if not always a " uniform twist." 8th. The fact, that a high rotary motion on the long axis of an elongated projectile fired from a rifle- gun, -will preserve that axis in the line of flight, when but for the rotation this axis itself would turn over, is well established. It is likened to the upright posi- tion of the axis of a top preserved by the spinning motion of the toy, but only whilst the spinning con- tinues. So a wagon- wheel will stand up a long while if rolling, but falls so soon as the rotation ceases. It may be difficult to find a satisfactory explanation for one as for the other. Nevertheless the fact exists, which is all that concerns the present discussion, and the three are of kindred causes. Breech-loaders were the first rifles used, and intro- duced early in the sixteenth century. But in the then existing state of the arts, it was found impossible to make a tight, unless it was also a permanent, breech. Hence muzzle-loading came exclusively into use for rifles, as well as for other fire-arms. The ball, to fit the groove, had to be patched and pushed home with great difiiculty and delay ; an evil which prevented its general introduction as a military arm. In recent contests of the French with the Arabs of Algeria, who attacked with pieces of superior range, it was found necessary to adopt for general use a weapon also of both range and accuracy superior to the common musket, and at the same time capable of rapid reloading. This necessity has resulted in the so-called Minie rifle, of a length and appearance much like the old musket, but somewhat lighter, with a little less bore, grooved, and throwing an elongated bullet. RIFLES AND EIFLED CA'NNON. 147 The Minie principle is, that the bullet shall ram home to its seat against the powder, not loosely but easily, yet a snug fit ; and when discharged shall so tighten in the bore by spreading or expanding, as to sink in the rifle-grooves, and take from them a motion of rotation. The principle is, therefore, carried out mainly by the form of the bullet, by which it is loose or tight as required, to load, or in discharge. But the present simplified Minie bullet has not been reached except by a succession of steps, each an improvement upon the other. At first, a round ball, by several blows with the ramrod, was flattened and spread into the grooves. But this pulverized the powder, and by increasing the transverse diameter of the ball occasioned it to present both a flattened and an enlarged surface for resistance of the air. IS'ext, to protect the powder from pulverization, a chamber for the powder was made, the chamber hav- ing abrupt shoulders against which a wooden saiot was driven, to rest on the shoulders and cover the chamber, and the ball was flattened by the ramrod against the sabot. Then, the carbine " a tige" (with a stem) was in- troduced. It consisted simply of a rifled musket- barrel, having a short steel pin projecting up from the breech-plug. Around this pin, the powder of the charge was poured loosely ; and against the point of it, an elongated bullet was driven by a saucer-headed ramrod, the blows of which caused the pin to enter the base of the bullet, and spread or wedge it open into the rifle-grooves. The fifth step was an improvement upon this, by constructing the bullet with a " culot," a steel wedge, in its large end, which wedge, entered in the base of a bullet, and driven up into it by the initial force of 10 148 RIFLES AND EIFLED CANNON. discliarge, forced open the base of the bullet, to fill tlie grooves, l^efore starting it from its seat. This steel culot was found, however, to fall out from the bullet in its flight, and having less range than the bullet, to occasion damage, especially when fixing at an enemy- over the heads of intervening troops. Which caused the sixth step, viz., to substitute a wooden for a steel culot. The seventh, and so far the last improvement, sim- plified the bullet to its present form at the base, which is that of a hollow or cup, in which the action of the powder on its first inflammation, before the projectile starts from its seat, produces the effect of the culot ; that is, spreads the base of the bullet into the grooves, giving them full effect in producing the spiral motion of the projectile. The grooved rings seen around the base of the bullet, form drags by which to keep it point foremost, in the line of the trajectory, and serve also to hold the tallow which lubricates and facilitates the entrance of the ball in loading, as well as its exit in discharge. The foregoing review of rifled small-arms, has been a necessary introduction to an understanding of rifled cannon ; because the steps in their construction are somewhat similar, beginning with breech-loaders, and culminating, as they have or appear destined to, in a gun, treated and used very much as the old musket of the military service was, when rifled and used with the last form of improvement in the Minie ball. In- deed, every form of rifled cannon thus far used, or which it appears possible to devise, is but an enlarge- ment of one form or another of the rifled small-arm, which is, or has been, in use, whether breech-loading as Sir William Armstrong's, or the muzzle-loading as General James' rifled cannon. KIFLES AND KLFLED CANNON. 149 EIFLED CANNON. For the two kinds, breecli-loading and nmzzle-load- ing, the shot are in both cases of iron, furnished with bands, or other parts, of softer material to take in the rifle grooves of the gun. It is indispensable, posi- tively unavoidable, either that the shot shall fit a chamber larger than the bore, and therefore load at the breech ; or else, load at the muzzle, go home to its seat loosely, and when fired, expand, under the action of the charge, into the grooves. This book assumes, that a breech-loading cannon to command the settled confidence of military men, never has, and never will be made, at least in considerable numbers for general service ; and that therefore the expansive principle is the one which must, can, and will, be successfully adopted. Popular favor now sustains the Armstrong breech-loading cannon. In time, it will sink to a level corresponding with its true merit. The twist of a small-ami rifle piece is, as has been said, at about the rate of a turn in say VO or 80 inches, or half a turn in a 40-inch baiTel, and it is a uniform twist — the same at all parts of the bore. But for a cannon projectile, of great inertia, an inertia to be over- come by the sudden exertion of a considerable force, the soft material which bands or jackets the projectile, would probably sWip oif before the shot could pos- sibly turn enough to correspond with any considerable initial twist in the groove. Therefore for cannon, it is considered necessary, and usually the practice, to begin with a very small twist, and increase it gradually, if not uniformly, towards the muzzle. General James rifles on this principle, and varies both the initial tvsdst, and the extent and rate of increase, according to the length of the gun and weight of projectile ; for evi- 150 BIFLES AND RIFLED CANNON. dently no fixed rule for all lengtlis and weights can hold good ; nor can the most judicious variations, or a rule for them, be determined, except hj numerous patiently and expensively continued experiments. There are several sorts of compound expanding can- non projectiles, for muzzle-loading pieces. Three are prominent : 1st, that which opens the rim of a wrought- iron cup into the rifle grooves, by action of the charge against the plane bottom of the cup, driving its supe- rior concavity up, and opening it against the inferior convexity of the rear of the projectile. This is Reed's shot. A second kind, has several copper rings, forming, with a circular iron plate behind them, a portion of the cylindrical part of the projectile. The powder, in discharge, acts on the circular plate, which is forced up against the copper rings, crushing and spreading them into the grooves. This is Cochrane's. A third, is General James', the distinguishing feat- ure of which is, that the inflamed powder acts in the hollow of a cup, formed on the rear of the projectile by means of sheet-tin, lead, and tallowed canvas, which, being yielding materials, are easily spread into the grooves, precisely as the cup of a Minie bullet is spread. The greased canvas presses when spread di- rectly against the bore, and facilitates the movement of this projectile, precisely as the Minie bullet is facili- tated by the tallow held in its rings. General James' appears to be the only cannon projectile possessing this important quality of lubrication, which is of most essential consequence both for loading and in dis- charge. In considering these several muzzle-loading projec- tiles in order to arrive at their relative merits, the points of comparison are : 1st, ease yet tightness in KIFLES AND RUaED CANNON. 151 loading, whicli arise from a union of yielding and lu- bricating materials ; 2d, such degree of ductility in the material used for expansion into the grooves, as will not cat or otherwise damage them, yet is of sufficient rigidity for holding to the grooves when spread into them. In all these qualities of ductility, rigidity, and lubrication, General James' combinations appear pre- ferable, though it is just to say this opinion is not universal, but warmly controverted. One other consideration is of great importance in estimating the relative merits of different compound projectiles, viz., the deteriorating effects of galvanic action, going on for a length of time amongst the com- ponent metals. Long observation in service can alone determine any such question with certainty, but it is not difficult to form a tolei'ably correct judgment from the relative apparent exposures to oxidation ; for ex- clude air and moisture, and the galvanic action ceases. In this respect, therefore, that projectile may safely be judged best, which to appearance most effectually by its composition and construction excludes air and moisture whilst exposed in store, or in the lockers of a ship. Any iron projectile for a rifled cannon, must un- dergo preparation of some sort, whether for a muzzle or for a breech-loading piece. The mere difference in expense of preparation for one kind over another, can- not be very great. It is the fact of preparation of any sort being necessary, which constitutes the evil ; for any preparation is liable to fail from some one of the nu- merous causes possible. But worse than all, is the greater possibility, or even probability, of the supply of prepared projectiles than of round-shot failing, be- cause considerations of economy will always tend to reduce the supply of prepared shot, but not balls, to a 152 EIFLES AND KIFLED CANNON. minimum ; and because, for half a century, balls haVe been accumulating little by little at all points, until their abundance everywhere is assured. If, therefore, any system of rifled ordnance or style of groove is superior to another for use "with round- shot, without impairing its fitness for use again with rifled projectiles, and if such style of rifling a smooth bore does not unfit it in any way for firing with round- shot, that system or style, it is reasonable to say, ought to have preference, other qualities being equal, or not essentially inferior. Artillerists contend that a rifled gun, loaded with a proper projectile, having a not too rigid material to be expanded or otherwise forced into the grooves, strains a gun less, with a given charge of powder, than a I'ound-shot does, notwithstanding the latter has, while the former has not, a windage. The claim is, that the smaller the windage, up to a certain point, the less the strain ; and that as the windage increases the strain also increases, until it becomes considerable, when the escape of powder is so great as to decrease strain. And the theory of it is, that the powder acts as a wedge between the top of the shot and the upper side of the bore over the seat of the shot, crowd- ing it down upon the under side of the bore, and causing it to bound and rebound, or "ballot," with great damage and strain upon the gun. As the wind- age increases, this action or balloting also increases in force, until after the opening for the escape of powder has caused a sufiicient vent, when the strain again de- creases. Thus, for example, it is supposed that the strain with j\ of an inch windage is greater than vnth jL.^ and it greater than none as in a rifled projectile. But that at ^V, the strain becomes reduced, and from that goes on reducing. On this principle it is, that EEFLES AND EIFXED CANNON. 153 when James rifles a 42-pdr. service gun of 7-incli calibre, charges it with 8 pounds of powder and an elongated projectile weighing 80 pounds, any number of discharges has not developed strain upon the gun or given any sign whatever that it is overcharged. It has been urged as an objection, that as all his expanding preparation, composed of lead and sheet-tin, flies from the shot on leaving the muzzle, it will scat- ter and produce damage as the culot of the small-arm bullet did. But this objection applies as a rule to all prepared shot, whether for miizzle or for breech-loading cannon, and is about an equivalent for a similar incon- venience arising from use of a sabot or hard wad, being one of the complaints against the Armstrong guns in China, when fired over the heads of troops. It is said, however, the Napoleon gun is an exception, and free from this objection, and caused no similar complaint at Solferino. — {See note^ p. 209.) As General James' may therefore (leaving out the Napoleon gun, for want of information) be considered the most prominent, if not the best of all muzzle- loading rifle cannon and projectiles, and in effect simply the Minie principle practised on an enlarged scale ; so is Sir William Armstrong's rifled cannon the most prominent of all breech-loaders, and in principle precisely like a breech-loading small arm, in which the chamber is larger than the bore, and the projectile, fitted with leaden bands that force into the grooves, obtains from them its rifle motion. Granting, what it is believed may be most justly claimed, that an expanding projectile fits the grooves as well as one forced into them from a chamber larger than the bore, a breech-loading cannon offers no ad- vantage, but on the contrary many disadvantages, as compared with a muzzle-loading piece. It, the breech- 154 BIFLES AND Kli'LED CANNON. loader, is less expeditious, for it requires more time to handle a heavy movable cannon breech-piece than to I'am home a charge at the muzzle. It is weaker, be- cause of the metal taken from the breech in continuing the bore through ; and is far more costly, because it must l^e of wrought-ii'on to give compensating strength against this cause of weakness. The muzzle-loader, on the contraiy, is strong enough if of cast-iron ; and any ordinary service gun may be rifled, yet serve also for balls should the quantity of rifled projectiles fail. Yet because the rifled projectile is inferior to the ball for ricochet firing, in range, accuracy, and pene- tration, and because in a cannonade at sea there is no certainty of avoiding the rebound from water without a worse certainty of wasting balls in the air, it be- comes doubtful if rifled cannon will ever come in use for broadside batteries in ships, however a gun or two for accuracy in the distance may be of service. The quality of range in the rifle projectile results from the increased weight of an elongated as compared with a round-shot of equal diameter, and consequent power to overcome resistance, without an increase of resistance, but on the contrary with an actual decrease, owing to the pointed shape by which it more easily cleaves its way through the ah. By reducing diam- eter and increasing the elongation, the weight of pro- jectile and charge of powder remaining constant, the range is increased, but the damage done decreases. In some cases this principle, as with the Whitworth rifle, has been carried so far as that the shot has taken the form of a bolt, and been sent to a distance of nearly 10,000 yards or 5^ miles. The uniformity of range and accuracy of direct firing are very gi'eat. A 12-pound field gun of 8 cwt., charged with 1 lb. 8 oz., at 5° elevation, threw 1,900 MOUNTING AND EQUIPPINa GUNS. 155 yards and upwards in twelve fires, varying but 40 yards in distance, witli an average deviation of but 3 feet from a line, As a rule, deduced fi'om Cap- tain Noble's experiments, the probable variations of rifle practice are in range only i- of wliat they are in smooth bore practice, and in deviations only ■^\. The author has witnessed extraordinarj' accuracy with an 80-lb. projectile, and 8 lbs. of powder, from a 42-pdr. bore, 2,000 yards distant , at which the pene- tration considerably exceeded 30 inches when the firing was direct. But after a grazing and rebounding, the shot struck the target sideways, buried about half their diameter in it, and fell back on the sand. SECTIOX IV. MOTJNTING AND EQITIPPIIfG OCXS. — TEAIXING OTT^s'S. ELEVATORS. — DISTEI- BTJTIOX OF DISPLACEMENT. — -SECUEING RUNS. — GEADTJATIXG DECKS. POETS. Next to the material for guns and their form and pro- portions, nothing relating to them exceeds in impor- tance the manner in which they are mounted, for on it depend the rapidity and accui-acy of their use. To place them on two parallel skids laid square to the breastwork for discharge only when the object of fire passes directly before them, as the Turks do or did in theii" forts, is one "^v^ay of mounting. Placing the gan on chassis can-iages to traverse with ease and rapidity through a sweep of 60 degrees, 30 each way, as is done in European forts, is another wa}^ Ships' Ijroadside guns are now mounted with facilities for manceuvring as far inferior to the European, as they are superior to the Turkish method in forts. 15G MOUNTING AND EQUIPPING GUNS. A ship, because of her own motion in turning, added to the motion of the object of aim, requires greater, whereas she has far less facilities for training guns than any fort ; an absurdity loudly calling for correction. So whilst a fort needs a pivot-bolt to pre- serve the central position of a gun in its embrasure far less than a ship, the fort has the pivot whilst the ship has not ; another absurdity needing, at least, ameliora- tion. And this amelioration would long ago have been applied, but for the fact, that hitherto a chassis or slide for broadside guns has not been admissible afloat, in consequence, 1st, of the room occupied on deck, which, unlike the terre-plein of a rampart, is of restricted width, and has other purposes than simply and solely to fight guns ; 2d, the objectionable weight of the chassis ; and 3d, the circumstance, that hitherto no ship's chassis or slide has combined with the car- riage so as to give simplicity of construction, along yf'itk facility and stability in transporting it. The present pivoted 10 and 11-inch carriages weigh enormously, and are exceedingly cumbrous. Their refinements and complications it may justly be feared are too great, too liable to derangement from enemies' shot, or from ignorance, carelessness, or forget- fiilness in the crews. The person selected for his marked intelligence, and well drilled to perform a par- ticular duty requiring great care and coolness, may be expected through habit to forget and neglect nothing belonging to his part. But in a hot fight, such person is as liable to be killed or wounded as any other. It is in a contingency of this kind that simplicity of con- strugtion exhibits its advantages. The pivot carriage in question has arrangements, but no facility for transportation, because they are foreign to its construction, are to be hunted up, fitted MOUNTING AND EQUIPPING GUNS. 157 and applied for use in an emergency, and again re- moved before the gun can be fired in its new place. Indeed, it is doubtful if these transporting arrange- ments are practicable or of any use in battle. They have, however, the merit of stability in this operation of removal from aft to forward and the reverse, when lateral stability is most tried by the deep-rolling mo- tion of a ship. Other chassis carriages which have been attempted in broadside, either have no means whatever of trans- portation, or having them are without facility, or are so narrow that their stability is insufficient under or- diuary, much less under deep roll. It is to pro-^ade against the effect of rolling that so great spread of the trucks, and the stability it causes, is given to the ship's common broadside truck-carriage. Much less stability answers against the mere pitching motion. Hence any slide-carriage which is got up at the expense of stability in the transportation, or which destroys ability to continue the gun's use in case the slide fails ; or which is complicated in construction, re- quiring more care to keep it in order, or more nicety in its management during the heat and confusion of battle than can be confidently relied upon from sea- men, may not be expected to receive continued favor in the naval service. Since the movement of ships by steam renders them not only independent, but also defiant of winds, be- yond a doubt the vessels of future contending fleets will become very much mingled, causing both bat- teries of the several vessels to be engaged simulta- neously as often as one battery alone. Hence the ne- cessity of so mounting the guns that the half crews may work their respective guns on both sides as rap- idly as the whole can one side, becomes more than 158 MOUNTING AND EQUIPPING GUNS. ever important. To devise a plan whicli will meet tMs new necessity, is less difficult than to surmount tlie barriers of j)rejudiee which beset the question and oppose improvement in gun carriages, whilst all sorts of innovations other than it ai'e countenanced, however incongruous some of them are; as, for example, nar- rower ships and longer guns, both which continually grow and conspire to produce great evils. There is, however, a show at least of reason in the pertinacity with which the service adheres to its an- cient carriage, precisely now of the pattern and pro- portions which prevailed in the days of Blake and Van Tromp. Its excellencies are palpable, indispu- table, and indispensable. ^Nevertheless, its defects are as palpable. They may, and they can be, every one of them, removed, wholly got rid of, and that too with- out the cost or the loss of a single good quality. The prejudice against all attempts at improvement have, it must be admitted, other solid ground in the absurdi- ties, not to say abortions, which those attempts have hitherto produced. For example : stability is a great and valuable fea- ture in the old pattern, a stability as before remai'ked not needed under the pitching motion of the ship, the only motion tending to overset a gun whilst standing in its port, but very much needed in transportation from port to port, or for securing when occasion re- quires in a fore and aft position and liable to be cap- sized by a deep roll. This needed stability the old carriage has, and it arises from the great spread given to the fore trucks, made fully equal to that of the hind trucks. When thus spread alike, the two pairs of trucks " track"- — one runs directly behind the other. Some one abroad took up the idea that reducino- the spread of the fore trucks increased the extent and MOinSTTING AND EQUIPPING GUNS. 159 facility of training, when forthwitli all our broadside truck-carriages are made in the same way to lose their stability. It turns out, however, that this loss of sta- bility results in no gain to the training, but in another serious defect, viz., greater weakness of the axle-tree at the shoulder, always its weakest part, but now made more than ever so because the dumb truck-bolts, and cap-square bolt, and their holes, are brought closer to this weak shoulder, or it to them, thus centering at one spot all these causes of weakness, which before were scattered.* Again, a Frenchman suspected that the breast-piece of a gun carriage was intended primarily to help train a gun by keeping the trucks off the water-ways, when he ought to have known that the sole purpose of the breast-piece is to save the wear of the trucks against the water-ways, and to form for the carriage a point of support as high from the decks as possible, placed so high to resist the tendency which all guns have to tip up behind when the ship rolls 10 degrees deep, and the lower half-ports are down. The fact is, that so far from a wider breast-piece than 4 inches giving greater, it materially reduces the train ; and the 18- inch breast-piece and port-piece combined, now given to the 9-inch guns (See Ord. Keg., Ed. 1860, p. 52), reduce the train a full half point each way. If figures do not show this, practice will, to any one who tries it. A British general ofi&cer, a soldier, altered the light 32-pdr. sea carriage for trunnion guns, putting into the carriage all the weight taken from the gun, when if left in the gun it would have served for strength as well as to check recoil. A seaman would have known the impossibility of taking weight out of a ship's gun, * These remarks apply only to the fore axle. The hind one, owing to the small weight it bears, is of but small account in any way. 160 MOUNTING AND EQUIPPING GUNS. without either putting it into the carriage, or reducing the charge of powder and with it the range of the shot. But the General christened his caniage the " Hardy Carriage," after Admiral Sir Thomas Hardy, who had nothing else to do with it than to stand its godfather. Hence it took people's fancy for a while, but was soon discarded on account of its weight, complication, lia- bility to become deranged, or to be rendered useless by swelling, shrinking, and warping of the wood, rust of the iron, &c., and because requiring more nice at- tention and care in the adjustment than is compatible with the confusion and hurry of battle, or with the in- telligence of seamen.* Officers have wasted years of time and quantities of money in tinkering away at this " Hardy Carnage," reproducing it every now and then in a slightly modi- fied form, but with a new name, though caiTying along the burden of its original inherent defects, which are destined surely and finally to crush it, and the system on which it is constructed.f * As an example : the lee and weatlier-guns require different degrees of compression, differing according to the degree of heel. Is it possible for any one, however cool or judicious, to work the "eccentric" always just right, or be certain he may not sometimes altogether forget to put it down ? The consequences of derangement by neglect, or even unskilful- ness, may be fatal to a gun's further use in a given action. (Major Anderson bad one of his few guns in Fort Sumpter dismounted from this very cause.) Hence the author has from the beginning opposed all compressor carriages. He believes them an abomination, and abhors the very idea of eccentricity as applicable to guns, shot, carriages, and to men in their relations with ordnance or gunnery. Compression applied to a 11-inch gun weighing, it and the carriage together, 9 tons ! the carriage already bound to the slide by this weight of 9 tons, would seem sufficient compression of itself, without further in- crease by clamp and screw power. (See note, p. 207.) t So far certainly, neither the service gives, nor inventors receive, encouragement to continue attempts at improving the broadside carriage, for hitherto such attempts have been attended with as little success as those aiming at the perpetual motion. But an improved carriage is yet MOTTNTING AND EQUIPPING GUNS. 161 All these absurdities in the various attempts at improvement have begotten the prejudice in question. But the service ought to take notice that the authors of them are soldier^, mechanics, or others having but little familiarity with or love for the sea. It is certain that a seaman, thoroughly practised in his profession, versed also in mechanics, ought, without seeking in- struction from abroad or from landsmen, to produce a carriage which shall possess all the acknowledged good and indispensable points of the old one, fre.e likewise from every one of its defects, and do it at the expense of but little weight and no room. It is natural nevertheless to conclude, considering the long wars the old carriage has passed through, when every inducement existed in the strongest form for rival nations to seek advantage in some new facility, such as might arise from change of equipment or of exercise, that every improvement in either, of which it is capable, should have been introduced. Undoubt- edly to a very great extent this is true, and it may turn out that many things, now regarded as better- ments, when brought to the test of war will fail. And whilst awaiting such new test, it is well to keep alive and hold in view the lessons of the war, and dis- card now, what at least would have been scouted then, whether of construction, equipment, or practice. possible on principles best illustrated by a simile. Thus, suppose a per- son bound on a journey, and a saddle-horse offered as a facility, but upon condition that the traveller should, -whilst accepting the horse's, relinquish his own legs, assuming that possible. Naturally, he would not incline to cxcliange the slower but more reliable, for the faster but less reliable, means of movement. But take the latter in conjunction with the former as a reserve in case of break-down, and the combination presents great advantage. So take the more reliable old carriage, pure and simple, in conjunction with a few primitive appliances not very liable to failure, yet good whilst they do endure, and the ground on which to build up an im- provement which will stand the test of experience, seems assured. 162 MOUNTING AND EQUIPPING GUNS. In the war, for example, a wholesome beam to ships was appreciated, as compatible with long breech- ings, and a muzzle for loading a good foot within the port ; which, 1st, eased recoil by its extent ; 2d, eased and hastened loading ; 3d, saved loaders from exposure to musketry, or to fall overboard if wound- ed ; and last, though most important, it saved them from deafness, or worse injury, when a neighboring gun trained sharp towards them happened to be dis- charged whilst they were sponging, loading, or ram- ming. This necessity for long breechings was one lesson of the war, now forgotten. First, for convenience in exercise it is common now to run a gun in as little as possible to barely reach the muzzle, and for that pur^ pose to get the longest-armed loaders to be found. This saves labor, both of running in and out, and, it cannot be denied, is a very enticing sort of economy. I^ext, long breechings come to be considered useless, because not used ; and then broad ships naturally be- come regarded as absurd, because narrow ships are both faster and more weatherly. In the war, short quick- working ships rendered the strong compact formation of fleets possible. Long- ships, fine lines, speed in sailing, and kindred qualities, are those only which shine out in a long peace, capti- vate the public fancy, and are lauded by progressive gentlemen, but find little favor Avith veterans. These are illustrations as relating to construction and equipment. A single circumstance will serve a similar purpose as regards practice. It is well known that guns are rarely exercised, and target or other firing practised, excejpt in smooth weather, and under easy sail, because then least troublesome; and target practice is of the two most rare. Indeed, it may be MOUNTING AND EQUIPPING GUNS. 163 said officers never risk throwing away their shot aimed to hit a target in rough weather, yet weather such as they certainly would be obliged to engage in during war, for which peace practice is but preparation. Hence they know but little as to how guns in such circumstances will behave. When a lee-gun is exercised under considerable heel or roll (8 or 10 degrees of inclination in a ship will tip the gun when nothing holds to prevent), officers get the gun in by the train-tackle, choke the luff, and observe that it does not tip up behind and throw the muzzle to the deck. But they do not as surely see that the train-tackle which drags the gun in and holds it, also hangs and is what prevents its tip. They are told that when the President fought her lee- battery against the Endymion, it was impossible to take in the slack of the train-tackle to catch the gun in at the extent of the recoil, and hence " hook-ropes " and other single cordage were used, with turns taken through the ring-bolts, around stanchions, tfec, and if actually firing shotted guns in a sea-way, instead of exercising only with tackles, the same effects would be experienced. Officers are instructed in the use of a French " chocking-quoin," to catch and hold the lee-gun in, irrespective of the train-tackle. The true test of this arrangement is, a lee battery fired, not merely exer- cised, in such a sea as the Wasp and Frolic fought in, or under such a heel as the President took in her run- ning fight with the British chasing squadron. In both instances it is apprehended the muzzle might, under some conditions of the moment, go to the deck before the train-tackle slack could be gathered in ; though it is by no means certain this is not an evil less than that of the gun's return to port, from which it must be 164 MOUNTING AND EQUIPPING GUNS, hauled iu, against the ship's inclination, for reloading. Under many conditions of the moment the gun might not tip, and if it did, the damage of it might be less hurtful than the delay occasioned by a return to tlie port. Alone, without the train-tackle, the chocking- . quoin would probably fail when tested by a battle like the President's or the Wasp's. In conjunction with the train-tackle, used as auxiliary to it, the chock- ing-quoin may be expected to prove a very useful and advantageous appliance. It is apprehended, however, that those who advocate it, probably those who pro- posed it, may have done so in view of superseding the train-tackle except for exercise, using the chocking- quoins as a sustitute.* The Marsilly Carriage is undoubtedly superior to every other form of truck-carriage. It trains more readily by the facilities it affords for the roller-hand- spike. In recoil, more weight is thrown on the hind dumb-trucks than is due simply to the weight bearing on them when at rest. Hence the friction they produce under the enhanced force of recoil, serves to check the recoil, though it must be admitted that this advantage is produced at the cost of damage to the decks, es- pecially if they be of soft pine and not of oak or hard yellow pine. In running guns mounted on this car- riage out to battery, if to windward or on an even •* In a late visit to the Naval Scliool — a wonderfully developed institn- tion, considering how recently founded, beautifully arranged, and admi- rably regulated — witnessing practice at the battery, the antlior was struck with the circumstance, that midshipmen unhooked the train-tackle before firing, and rehooked it afterwards. Better keep them to the practices of the sea. It is easier to establish right than to correct wrong habits and practice in exercise. And not a bad idea to give them inclined, like weather and lee, as well as level platforms to exercise on ; perhaps a single adjustable platform. One might be arranged to fire a light gun from, when under a motion corresponding with a ship's roll. As it is, their practice will hardly make marine gunners. TRAINING GUNS. 165 keel, the roller-liandspike is used to assist. But in running out to leeward with much heel, the handspike is omitted, and the friction of the dumb-trucks so fax- checks the movement, that it results with a small and harmless blow or shock on the side. But whether on this or any other form of truck- carriage, the 9-inch gun, the heaviest used in broad- side, weighing, it and the carriage together, upwards of five tons, is too heavy for a pine deck of any kind, white or yellow, which splinters, not so much after all by friction of the hind dumb-trucks, as by the crushing weight upon the fore-trucks, and the small point of contact with the deck which they afford to sustain the enormous weight. It may probably turn out, that all guns of greater weight than the 42, if not of the 32- pdr., will need to be used on a slide of some descrip- tion, and this too without reference to the ease of working them, but solely to the destructive effects of so great weight of decks unprotected by metal plates, which may be placed beneath slides at their points of contact with the deck. TEAINING GUNS. The extent of train depends upon two things — the width of port, and the length of gun. A gun like the old 32-pdr. of the war, weighing 61 cwt., and 122 inches extreme length, when standing in its port of •42 inches width, on a carriage having a breast-piece of 4 inches, projects 33 inches from the ship's side if pointed directly abeam. This length of gun and width of port exactly correspond. More length of one or width of the other would not alone favor an increased extent of train. Both together will. And although shorter carriage guns usually have this same width of 166 TRAINING GUNS. port, it is wider than necessary for the extreme train of a short piece, but facilitates and increases ordinary train : extreme train being that which may be given to a gun when in one side of the port, and ordinary that given when in the centre. This common old style long 32-pdr. gun, which measures 5 feet 6 inches from the centre of the trun- nions to the face of the muzzle, when mounted on the truck-carriage and standing in the middle of a port 42 inches wide, has an ordinary train of 2 points forward or abaft the beam. When rowsed sufficiently forward or abaft the centre of the port, it is possible to train the gun full 38° forward or aft without wooding the muzzle, or bringing it within the outside of the port. The breast-piece then forsakes the side altogether, and becomes therefore of no account, whether narrow or wide. If, with this length of gun, the port were wider, it would not increase this possible train, but there would then be no necessity for rowsing the gun so far aside from the middle of the port. This possible extent of training, 38°, may be reached equally as well on a truck as on a slide-carriage, notwithstanding all that has ignorantly been written about the difference of training to be obtained on one more than on the other. In point of fact, neither has the advantage in extent of training over the other. The real and only difference is, that whilst extreme training is a most awkward and difficult operation on trucks, it is easy and quick on a slide. Moreover, for the long 32-pdr. in question there is no possible gain in "widening the present 42-inch port for a slide, although, as remarked, extreme train would be more easily got on trucks with a wider port. Indeed, if the port were just twice its present width, the extreme train on trucks would be got with the gun standing in the centre of it, and the TEABSTLNG GUMS. 167 extreme train and the ordinary trains would then be aliko* The present 9-inch, the longest as well as the heav- iest broadside gun now or ever in use, a foot longer than the old long 32-pdr. of the war, and showing all this extra length from the trunnions out, is capable of being trained, whether on trucks or on a slide, full 50° forward or abaft the beam, if mounted in a port 62 inches wide, or 20 inches wider than the present port, and will not when so trained bring its muzzle at all within the outside of the port, because that length of gun and width of port ai'e relatively adapted. But with the present port, the 9-inch gun is, like the 32- pdr., capable of only 38° extreme training, at which it will wood against the side of the port, although its muzzle will then be well without the ship's side, and show the gun that much longer than is necessary for the port. All this is true of that gun also -whether mounted on a slide or on trucks, ^vl■itel•s to the con- trary notwithstanding. The real difference is, as with the 32-pdr., that on trucks the extreme train of 38° is obtained only by great and exhausting labor, and loss of time, whereas on a pivoted slide it is got as easily and almost as readily as the ordinary train. Its ordi- nary train, on a slide, is 35°, but on tmcks with a regulation breast-piece of 18 inches, it is less than 20°.f * It lias been said that a slide carriage is deficient in projection as compared with the truck. This is an error, for with equal train tliere is equal projection— the train being called equal when two contiguous guns with wlii'ch the test is made, are brought to bear on the same object, and tlie projection then measured. t This 9-inch gun has no more length of bore than the old 32-pdr., though its extreme length is one foot greater. The foot in extra length, all of it being in the muzzle, would.cause it to project a foot more from the port, when pointed abeam, than the 32-pdr., which has a projection of 33 inches. Consequently the 9-inch would have a foot more recoil tlian the 32-pdr., and will need a ship of two feet more beam— one 168 ELEVATOKS. These remarks and those elsewhere made are not intended to favor wider ports ; although, whether so intended or not, they do favor, as all other scrutiny will and must favor the pivoting of broadside guns, provided it can be done without sacrificing room or facilities for transportation. These considerations are apart from the increased facilities which a slide offers for fighting both sides Avith the half crews of each gun, even with the present restricted allowance of men. This discussion makes no account of channels and chain-plates. They have no business in the way of batteries, and if constructors put them there, officers should discharge a gun when pointed at the enemy, being sure that the shot will make a path for itself by sweeping away all illegitimate obstruction ELEVATORS. A ship's gun elevator needs to be, 1st, solid and stable ; that is, not liable to crush, or to fly out, or even recede, under a discharge. In this respect the old quoin is defective. 2d. It requires readiness of adjustment, and certainty, in which respects also the old quoin is defective, because it cannot be adjusted to any required elevation except by a series of rough un- certain approximations, as any one may discern b}' trials with it. 3d. The elevator ought to be so out of the way, as the old quoin is when under the gun inside the carriage, as to be free from much liability to damage ; but if damaged, it should be cajDable of ready removal and replacement, as the old quoin is, for each battery. It would also involve more labor and time in run- ning out to battery, vpere it not tbat the port-sweep ordered (p. 52 Ord. Reg.), which is a foot wide, reduces both this labor and the projection to an equality with the 32-pdr. ELEVATOBS. 16[) involving no disability nor mucli delay. 4tli. It should be capable of rapid adjustment, in order to preserve the level of the gun when the inclination of the deck changes rapidly, as when the ship luffs, tacks, or bears up suddenly and quickly. The French prefer as an elevator the vertical screw, in which preference we follow them. The English on the contrary adhere to the quoin, because they con- sider the screw deficient in rapidity and stability, as also liable to injury by bending, or by bruising the thread, either of which might, it is conceivable, amount to total disability of the gun, such as should result from nothing short of bursting or dismounting it. Every elevator should be viewed in the light of this enumeration, and judged accordingly. In discussing this subject, it is quite common to argue that the rolling of a ship sufficiently adjusts the elevation. This is in part true. But the heel of a ship in action may reach or exceed the average of 5 degrees. If under that heel a lee battery is levelled with the hoiizon, and makes an angle of 5° with the plane of the deck, then when the ship tacks and the deck takes an 0]3posite inclination of 5°, this batterj', now brought to windward, -will, if quoins remain un- altered, point at an elevation of 10° with the horizon, which is more than any ordinary amount of rolling would adjust for firing level, at an enemy moderately distant. The case is also similar but not quite so bad, when a ship, by the mnd with her guns levelled, bears up and runs before the wind on an even keel. This reasoning relates to sailing vessels. How the matter will stand with screw steamers ; whether theii' excessive rolling, at war with all accuracy, may not be sufficient to adjust the level provided the guns are set parallel to the decks, is a question to be decided 170 DISTRIBUTION OF DISPLACEMENT. by experience of tliose who have sailed (as the author has not), or who do sail in screw ships. DISTKIBUTION OF DISPLACEMENT. There is a growing tendency to overload ships, not only with a heavier description of guns, but by adding as many of them as there is room for. Each gun and its opposite added to a frigate's bat- tery, involves much weight in addition to that of the guns themselves, for they are useless without men, their clothing, provisions, and water, also powder and projectiles to the extent of at least one hundred rounds, fifty for each broadside. Taken up in detail, these items weigh severally as follows : Assuming that a ship will have an average of 100 days' provisions and water, and the consumption per day caused by each man to be about 12 pounds (8 of water and 4 of food), the 15 persons, including pow- der-boy, allowed to serve the single 32-pdr. and its op- posite added, will have put on board the ship for them, 20,000 pounds of wood water and provisions alone. The men themselves will weigh 2,500 pounds, their clothing and bedding 1,000 pounds, and the two guns (that added and its opposite) with theii- carriages, 16,000 pounds. Sum up all these items of weight, and the aggregate which the addition of a single 32-pdr. gun to the broadside of a ship causes, will be found to exceed twenty tons ! Sir Howard Douglass is of the opinion, that British ships are overladen with batteries. Many persons entertain similar opinions respecting our own practice. It arises possibly from neglect to consider, that each gun added involves a much greater weight, as is shown, than that of the gun itself The evil grows of course with the weight of guns. DISTRIBUTION OF DISPLACEMENT. 171 being somewliat greater witli a 9-incli than. witL a 32-pdr. The displacement of a frigate, such for example as the Congress, when loaded is 2,522 tons. This meas- ures exactly the aggregate weight of her hull, spars, rigging, sails, tackle of all sorts, ballast, tanks, pro- visions, water, stores, battery, equipment, and " ship's company," which latter term, being the equivalent of personnel, properly embraces all the people attached and on board, crew and officers, though most commonly applied to crew alone. As launched, her hull had a draft of 15 feet 6 inches ; when loaded for sea, the draft is 22 feet. And the 2,522 tons of displace- ment, may in general terms be divided up as follows : that of the hull, 1,470 tons ; spars, boats, rigging, sails, and tackle, 228 tons; ballast, tanks, provisions, water, and ship's stores, 514 tons; battery and its equipments, together with ammunition of all sorts, and ordnance stores, 260 tons ; officers and crew, with their personal effects, 50 tons. The Congress' measurement, as recorded in the Navy Eegister, is 1,86Y tons.* This shows her to * This is presumed to be " Government," or which is supposed the same, " Custom House " or " Registered Tonnage," and is calculated by the following Eule : Measure the ship's length, on the spar deck, from the fore side of the stem to the after side of the stern post ; from this length deduct § of the breadth (measured from outside to outside of the frame, not including the planks) ; multiply the remainder by the whole breadth (measured as be- fore), and that product by half the breadth. Divide this last product by 95, and the quotient is the Government Tonnage. The above rule is for double-decked ships, and assumes the depth to be equal to half the breadth, however far that may in reality be from the fact. For single-decked ships, the rule is the same, except that the actually measured depth is that used in the calculation. " Carpenter's Tonnage " is length, breadth, and depth multiplied, and the product divided by 95. It is usually a small percentage greater than the other. 172 SECURING GUNS. carry, including her hull's weight, 700 tons more than she measures, and that the larger part of the actual displacement, even of this entirely wooden ship, is taken up by the hull alone. Nothing is clearer, than that as the weight of hull increases, every other weight, including battery and its dependencies, must decrease. This leads most naturally to the considera- tion of " iron-clad," " iron-plated," " armor," " coat of mail," or " cuirass ships" (as they are variously styled), coming in use by England and France, the hulls of which, in consequence of the iron covering they carry, a material eight times heavier than wood, are so weighty as to take up a large share of the displace- ment, lea\'ing comparatively little for battery, etc. In a future section this question of iron ships will be duly considered. SECUEING GUNS. In securing guns for sea, it is important, not only to be sure they cannot break away if the ship be tlu'own on her beam ends (and who can tell that lack of "such security may not have caused the loss of men- of-war foundered at sea and never heard from ?), but also that a circulation of air beneath the carriage should be, to some extent at least, provided for. To effect this last purpose, usually a single block of wood is placed beneath the hind axle. It is worth remark- ing, that this block, when placed under the middle of the axle-tree, has been found to belly it up, and when placed on one side to warp and twist the carriage. A pair of blocks is therefore advisable. In heavy weather, sometimes guns on board ship are housed in, the purpose of which is threefold : 1st, it divides the weight of battery between the futtock- GEADUATTNG DECKS. 173 frame and the keel, instead of remaining, as it does when secured out, on the frame alone ; 2d, it greatly relieves pressure outwards upon the frame ; and 3d, it brings the centre of oscillation of each battery, star- board and port, near to the centre of vibration* Any one can see, that the actual movement in a vertical arc, made by a ship's battery when secured out, is through a considerable space in a short time, a few seconds; and that this velocity, multiplied by the weight, that is the momentum (see p. 17), then be- comes veiy great. It is evidently to be resisted (see inertia, p. 14), reduced, and finally stopped, by a cor- responding stress on the futtock-frame, which stress is not received vertically, but at an angle outwards tend- ing to open the ship and the water-way seams. All this is remedied by reducing the arc of vibration, which is done by housing the battery in. GEADUATING DECKS. If the people below on the gun-decks of a ship could always see an enemy at near firing ranges, when obscurity fr-om smoke is greater than in distant firing, graduation of decks with the beam would be of minor consequence, for each captain of a gun would find a sufficient guide for his aim in the object itself But the object, obscured by smoke of close action, is invis- ible a large portion of the time except to the com- mander on the highest deck, and frequently to him also. The hulls of ships are to him oftener invisible than the mastheads. Seeing then the object as the commander does when oftentimes no one else can, if he knows how a gun under his eye angles with the * Refer to page 29, where the distinction is seen between the centre of motion 6, and the centre of oscillation as, of the Figure. 174 GBADUATING DECKS. beam wlieii pointing at the object, he knows likewise how to order every other gun set to obtain the same aim ; and the order can be obeyed with precision, if only the decks at all the ports are graduated, especially when caution has been used to graduate for a concen- tration at some moderate distance, say 600 yards. Therefore to determine, when a gun is aimed, what its angle of aim with the beam is ; or know, if directed to be laid at any given angle, when it is so laid, decks, at each port having a chassis or slide-carriage, may be graduated to points and fractions of points. Now, if an order issues to train to a given angle with the beam, its execution is but guess-work, depending upon the unaided judgment of division officers — more fre- quently on that of captains of guns. With slides and graduated decks however, the direction of aim as re- lates to the beam is a sure thing, not calling the judg- ment at all into exercise. It is probable that no scheme for concentration of fire can ever be success- fully carried out, until all broadside guns shall be mounted on pivoted slides. The process of graduation for the decks is simple, easily explained, and readily put in practice. With a radius of 7 feet 4 inches or about that, strike a semi- circular arc, the centre being under the port centre and at the water-ways. The beams overhead, or the forward or after ends of the hatchways, or their cross- bars, are guides by which to strike a beam-line from the centre aforementioned ; and where this beam-line cuts the arc, drive a composition scupper nail in the deck, as the zero or " right abeam" mark. With this radius of 1 feet 4 inches, 18 inches is the cord of one point, or its equal ll^ degrees. Therefore, take 18 inches in a pair of large carpenter's compasses, and lay off on the arc one, two, three, and four points each POETS. 1*75 way from zero. Mark these points witli as many big- headed composition nails. Then, a pivoted gun-slide no longer than Yi feet, set with its rear at any one of these graduations, will have its gun laid to angle that number of points with the beam. A truck-carriage, when laid in a direction parallel to any radius of the graduated arc, angles, approximately at least with the beam as such parallel radius does. POETS. The author has for years striven for pivoted broad- side guns, and the narrow ports which pivoted guns admit, as well in a ship as in a fort, where the throat of an embrasure is never over 21 inches though a ship's port is usually 42 inches. A narrow port was formerly important as a protection against grape only ; now, it is more important because of the long-range accurate rifle, substituted for the smooth-bore musket. The new British iron ship " Warrior," is said to be fitted with permanent pivoted broadside guns, and permanently narrow ports of 21 inches on her main- deck. To this as a permanency, two objections it is conceived will arise. One is, that a pivoted gun as a fixture, not convertible at pleasure for use on a truck- carriage, will prove injudicious in a broadside main battery, which ought not to depend on any one thing, as a fighting-bolt, or any other one piece of machinery, such as, if deranged, disables the gun or throws it completely out of action ; and a convertible carriage needs a convertible port — that is, one which is narrow when the pivoted slide, and wide when the truck-car- riage is used. A second objection to permanently narrow ports may be, that the ancient wide port is necessary, at 176 PORTS. least at times, as in calms or when before the wind, or head to it in steamers, to clear a gun-deck below from suffocating and blinding smoke. With a wind, and that across the ship, the wide port is not necessary as an egress for smoke. To obtain, therefore, a convertible port, wide for the use of a truck-carriage and the escape of smoke, or narrow for a pivoted carriage, and affording protection to loaders and others about a gun from Minie bullets, a shutter 10 inches wide on each side of the port, hinged in the vertical plane of the pivot, is proposed, of a material which if hit by a heavy projectile and knocked inboard, will occasion no especial damage amongst the people. A series of experiments shows that a Minie ball will perforate any practicable thickness of india rubber, hair, cotton, wool, or oakum in bags, but cannot be driven into a sand-bag more than 8 inches, however near. So it will, at a short range, perforate 2 inches of oak. But firing from 50 yards at an oak board one inch thick, faced with an inch or even half an inch of sand, the sand being placed between the board and a covering of canvas, the Minie bullet will not penetrate the oak, but will turn in the sand, strike the wood sideways, and rebound from it with such force as not even to remain in the sand, but fall to the ground or water. So light a shutter as this, hinged in a port, may afford important shelter. It will not need to be opened for training whilst a gun remains pivoted, but will when the gun is used on trucks. A third objection to permanently narrow ports will appear in an emergency, such as when, owing to stress of weather, it is necessary to launch a gun over- board, which must be done through the port, or when for any reason it becomes necessary to get guns out or QUAKTERING AND STATIONING MEN. 177 in tlirougli the ports. The full width, of port, 42 inches, and more in fact, is needed for the trunnions of a 9-inch gun, and the heavy 32-pdr. has not much width to spare. SECTION V. QUAETEEING AND STATIONi:SG MEN. — STOWAGE OF POWDEE. DEOWOTXG MAGAZINES.— SHELL ROOMS. Before quartering a crew at their fighting stations, as is well provided for in the Ordnance Regulations, on a general plan set forth many years ago in the first edition of this work, now long out of print, the watch hill is first to be framed and filled, because it is the basis of the quarter as it is of all other ships' station bills. The preliminary step towards filling it is, selec- tion of the petty ofiicers, particularly the boatswain's mates, quarter-masters, quarter-gunners, captains of tops, and coxswains. The selection is much facili- tated by the system of honorable discharges, and will be more so when the practice prevails of issuing them only on consultation by commanders with the lieuten- ants of a ship, who come much more frequently and intimately in such connection of duty with the crew as afibrds ground for correct judgment of their merits ; and when such honorable discharges are granted only for positive qualities, never for the mere negative merit of simple good behavior. A venial ofifence, such as is to be looked for occa- sionally and viewed charitably in the seaman, if he be active, forward, and prompt, especially in emergencies, will not weigh against him in the question of dis- charge, nor mere inoffensiveness in favor of one who is 178 QUARTERING AND STATIONING MEN. unequal to his duties or backward in performing them. Although a landsman or person of inferior rating might properly get a good discharge and yet possess no surpassing merit, it is hardly possible that a seaman or petty officer can justly command one, unless worthy a continuance in that or a higher position when reen- listed.* In the gradations of petty officers, a leading top- man, young, active, energetic, of commanding personal qualities such as give him moral force with his com- rades, becomes a second captain, then first captain of a top. From amongst those who have served a couple of cruises with marked credit in this capacity, the best boatswain's mates are selected, who need to have had their capabilities for leading and controlling men, with a due mixture of good temper and spirit, the suaviter and fortiter, not only tested, but cultivated by such experience as captains of tops get. Becoming older, they settle naturally and appropriately into the rate of quarter-master, which calls for sobriety, judgment, general reliability, and watchfulness ; or that of quar- ter-gunner, Avhich requires steadiness, with a taste for the minute and constant vigilance which the care of a battery and its multitudinous equipments involve, as well as a certain necessary degree of practical knowl- edge and experience in that peculiar line ; or captain of the forecastle, whose very title is suggestive of * The author, on discharging a sloop-of- war's crew at the expiration of a cruise at sea, adopted a plan on the principles here explained. He required each of the five lieutenants to mark "honorahle" or "ordinary," against the name of every enlisted person in his watch bill (being a sailing ship), giving his own independent judgment as formed by observation, without consultation at the time with any other person. Three out of the five, and one of the three the first lieutenant favoring, the honorable discharge was sure, otherwise not, but then depended on the commander's scrutiny — subject of course in all cases to his disapproval, for reasons sufficient to himself. QUAKTEEING AND STATIONINa MEN. 179 Neptune himself, changing only his symbol of sov- ereignty from a " trident " to the " marlinspike." The various rates thus fiEed, the difficulties of the quarter bill are smoothed, and the whole process of distributing the men rendered simple, easy, and uni- form for the whole service in every class of vessel, by aid of the new Ordnance Regulations just issued, which will be found to make the most of the limited number of men allowed as the complement of ships, and to divide the force at quarters between the pow- der division, the guns' crews, master's division on deck in sailing ships, and the engineer's department in steamers, by an ari-angement bearing marks of long, deliberate, and careful consideration, and presenting the whole subject in a well-digested shape, freed from the incongruities and inconsistencies not unusual in similar works. Doubtless for good and sufficient reasons, which however are not explained, the ancient plan of taking a half of every gun's crew from each watch, so that when going to quarters in the night, the watch on deck would afford a half-crew for each gun to clear away every one of that side on which an enemy might be discovered, whilst the watch below, composed of the other half guns' crews, would be getting up the hammocks, supposing the watches " to turn in and out with each other," is changed, and a new plan substi- tuted, which takes all the odd guns' crews from the starboard watch, and all the even guns' crews from the port watch. Therefore, although it is provided that on assembling at quarters for action, both watches being on deck, the starboard watch shall " cast loose and provide" the starboard guns, first part the odd and second part the even guns, and the port watch the port guns, first part the even and second part the 12 180 QUAETEEING AND STATIONING MEN. odd, it is presumed witli one watch only on deck the guns on that side towards the enemy would be those cast loose, even although the port crews might be called upon to prepare the starboard battery, or the starboard crews the port battery, and that in such an emergency the first part of the port crews would always take care of the even guns on whichever side, and the first part of the starboard crews take care always of the odd guns. It might, however, be best to define this by special shij) regulations, in the ab- sence of a general rule, which, if it exists, has escaped notice. Another new arrangement, which is a marked change, and apparently an improvement on the former plan prescribed for fighting both batteries of a ship at once, is introduced by the new regulations. Formerly, for example, Nos. 1 and 2 guns (and coiTesponding pairs) starboard were served by the first part of crew No. 1 and second part of No. 2, which half-crews inter- changed, a portion of them, from gun to gun, although never on ordinary occasions accustomed to drill or receive instruction together. As members of guns' crews they were strangers to each other, and not there- fore so fit to act together in battle, as if used to do so in the drill carried on preparatory for battle. Under the new system substituted, the whole crews of No. 1 and all odd guns, are made to serve guns Nos. 1 and 2 starboard, and corresjDonding j)airs of the starboard battery ; that is, the odd guns starboard and the even guns next abaft ; the captains, loaders, spongers, train-tackle, and shot-men of the first parts standing fast or serving exclusively at the odd guns, and of the second parts at the even guns, whilst the rest interchange to aid in running them out alter- nately. And the whole crew of No. 2 serves both No. QUAKTEKING AND STATIONING MEN. 181 2 and No. 1, and so with other corresponding pairs port side. That is, the even crews serve the even port guns and the odd gun next forward, the captains, loaders, and spongers, train-tackle, and shot-men of the first parts standing fast or serving at the even, and of the second part at the odd guns, whilst the remain- der alternate. The powder-boys, by this plan, go with their crews. By the former one they were per- plexed as to which guns they ought to serve, each boy seeing part of his crew at one gun and part at another. The port watch is put to serve the port battery, and the starboard watch the starboard battery in the new system; and the even crews are taken from the port and the odd from the starboard watch. Every even crew knows that it serves its own gun on the port side and the one next forward ; and every odd crew knows it serves its own gun starboard and the next gun aft ; and the powder-boys can thus cal- culate easily which are the guns to be served by them, besides knowing they are right by observation. When there is an odd gun in the battery, or an odd gun in a division, or an odd number of 8-inch guns in the waist of a ship armed principally with 32-pdrs., or when a gun and its opposite are served exclusively by marines, an inconvenience arises in working both sides by this, as well as by any other plan, and the inconvenience is aggravated when a launch or hatchway intervenes between a gun and its opposite, to be served by one powder-boy, or by one shot-man with shells. There is this evil which, however, might result from the new plan. By Art. 156, p. 38, Ord. Eeg., at inspection-quarters the crews are directed to see all equipments in order and in place, without specifying. Presuming that No. 1 gun's crew looks out for No. I's 182 QUAKTEELNG AND STATIONING MEN. equipments and opposite, and No. 2's crew for No. 2's equipments and opposite, it would result that, for ex- ample, the second part of crew No. 1, which had at in- spection looked after gun No. 1 port side, and when called upon to cast loose, as required by Art. 157, would attend gun No. 2 starboard, which gun had been looked after at inspection by the second part of crew No. 2, might find that gun deficient through the negligence of others than themselves who would suffer from it. It may certainly be best to complete the change of system, so that those who are to clear away a gun, should be those also appointed to look after its preparations and constant readiness in all respects for action. These suggestions are thrown out in no spirit of unfriendly criticism, and it may be that the subject /■s met in the Regulations, but has been overlooked. Stating, therefore, more fully the question which the foregoing suggestion involves, may it not be best, that the parts of crews appointed by Regulations to cast loose certain guns for action, should likewise be required at inspection-quarters to look after the equip- ments of those same guns ? Experience will conclusively demonstrate one thing connected with working one or both sides, A'iz., that as guns are now mounted, the number of discharges in a given time, "with a given battery manned as per regulations, will be as the men employed, not as the number of guns, whether the men work one side alone, or both sides at once. And if working both sides, it will amount to the same thing as regards the number of discharges in a given time, whether every alternate whole crew stands fast at one gun to load and fire it, so that only every alternate gun of a battery is fired, or whether every gun is served by the half-crews alter- nating as per regulations. By either method, a gun QUARTERING AND STATIONING MEN. 183 on one side, or one of a pair on eacli side, or every alternate gun of eacli side should discharge a shot once in 75 seconds of time. The subordinate places at the guns are filled by selections made on principles such as were pointed out in the appendix of the first edition of this work, but now well and lucidly explained in the Ordnance Regu- lations, Ed. 1860, p. 18, therefore here omitted, be- cause it is no part of the present plan in publishing this edition to reprint any thing from the Ordnance Regulations, inasmuch as that useful work is supposed and ought to be in possession of every naval officer, young or old. The selections for hoarders^ piTcemen^ sail-trimmers^ firemen^ pumpmen^ with the principles on which made, and the manner of exercise, are stated in pp. 20, 21, and 90 of that book. It will be observed in the Regulations, and is known to be universal in the service, that first board- ers, pikemen,